MALLOC, mspanSpecial < gcBitsArenas;

# Memory profiling
MPROF < profInsert, profBlock, profMemActive;
profMemActive < profMemFuture;

# Stack allocation and copying
gcBitsArenas,
  netpollInit,
  profBlock,
  profInsert,
  profMemFuture,
  spanSetSpine,
  fin,
  root
# Anything that can grow the stack can acquire STACKGROW.
# (Most higher layers imply STACKGROW, like MALLOC.)