PREPARE_GC        279 src/mark-compact.cc   ASSERT(state_ == PREPARE_GC);
PREPARE_GC        684 src/mark-compact.cc   state_ = PREPARE_GC;
PREPARE_GC       2360 src/mark-compact.cc   ASSERT(state_ == PREPARE_GC);
PREPARE_GC        483 src/mark-compact.h   bool in_use() { return state_ > PREPARE_GC; }