free_list_head_  1444 src/hydrogen.cc           lists_[current].next = free_list_head_;
free_list_head_  1445 src/hydrogen.cc           free_list_head_ = current;
free_list_head_  1465 src/hydrogen.cc           lists_[head].next = free_list_head_;
free_list_head_  1466 src/hydrogen.cc           free_list_head_ = head;
free_list_head_  1497 src/hydrogen.cc   if (free_list_head_ == kNil) {
free_list_head_  1522 src/hydrogen.cc           lists_[current].next = free_list_head_;
free_list_head_  1523 src/hydrogen.cc           free_list_head_ = current;
free_list_head_  1553 src/hydrogen.cc     lists_[i].next = free_list_head_;
free_list_head_  1554 src/hydrogen.cc     free_list_head_ = i;
free_list_head_  1570 src/hydrogen.cc     if (free_list_head_ == kNil) {
free_list_head_  1573 src/hydrogen.cc     int new_element_pos = free_list_head_;
free_list_head_  1575 src/hydrogen.cc     free_list_head_ = lists_[free_list_head_].next;
free_list_head_  1232 src/hydrogen.h         free_list_head_(kNil) {
free_list_head_  1278 src/hydrogen.h   int free_list_head_;  // Unused elements in lists_ are on the free list.