RUBY_VM_VALID_CONTROL_FRAME_P 1457 eval.c             while (RUBY_VM_VALID_CONTROL_FRAME_P(cfp, end_cfp)) {
RUBY_VM_VALID_CONTROL_FRAME_P  981 vm_core.h        (!RUBY_VM_VALID_CONTROL_FRAME_P((cfp), RUBY_VM_END_CONTROL_FRAME(th)))