},
	EvGCBegin: event.Spec{
		Name:         "GCBegin",
		Args:         []string{"dt", "gc_seq", "stack"},
		IsTimedEvent: true,
		StackIDs:     []int{2},
	},
	EvGCEnd: event.Spec{
		Name:         "GCEnd",
		Args:         []string{"dt", "gc_seq"},
		StartEv:      EvGCBegin,
		IsTimedEvent: true,
	},
	EvGCSweepActive: event.Spec{
		Name:         "GCSweepActive",
		Args:         []string{"dt", "p"},

		// This is not the right GC cycle.
		return curCtx, false, nil
	}
	if o.gcState == gcNotRunning {
		return curCtx, false, fmt.Errorf("encountered GCEnd when GC was not in progress")
	}
	if o.gcState == gcUndetermined {
		return curCtx, false, fmt.Errorf("encountered GCEnd when GC was in an undetermined state")
	}
	o.gcSeq = seq
	o.gcState = gcNotRunning
	if err := validateCtx(curCtx, event.UserGoReqs); err != nil {

	// N.B. Only one GC can be running at a time, so this is naturally
	// serialized by the caller.
	trace.seqGC++
}

// GCDone traces a GCEnd event.
//
// Must be emitted by an actively running goroutine on an active P. This restriction can be changed
// easily and only depends on where it's currently called.
func (tl traceLocker) GCDone() {

GoStart dt=7 g=24 g_seq=13
GoLabel dt=1 label_string=2
STWBegin dt=4128 kind_string=23 stack=37
GoUnblock dt=64 g=25 g_seq=8 stack=38
HeapAlloc dt=25 heapalloc_value=16970376
GoUnblock dt=24 g=3 g_seq=5 stack=39
GCEnd dt=6 gc_seq=6
HeapGoal dt=7 heapgoal_value=34360936
ProcsChange dt=46 procs_value=8 stack=40
STWEnd dt=49
GoBlock dt=756 reason_string=15 stack=27
GoStart dt=10 g=3 g_seq=6

	gcsToEmit := []struct {
		symName string
		symKind sym.SymKind
		gcEnd   int64
	}{
		{"runtime.gcdata", sym.SDATA, dataGcEnd},
		{"runtime.gcbss", sym.SBSS, bssGcEnd},
	}
	for _, g := range gcsToEmit {
		var gc GCProg
		gc.Init(ctxt, g.symName)
		for _, s := range state.data[g.symKind] {
			gc.AddSym(s)
		}
		gc.End(g.gcEnd)
	}

	/* pointer-free bss */

GoUnblock dt=6 g=100 g_seq=6 stack=22
GoUnblock dt=29 g=86 g_seq=6 stack=23
HeapAlloc dt=53 heapalloc_value=103773088
GoStatus dt=10 g=3 m=18446744073709551615 gstatus=4
GoUnblock dt=7 g=3 g_seq=1 stack=24
GCEnd dt=3 gc_seq=5
HeapGoal dt=6 heapgoal_value=207987496
ProcsChange dt=45 procs_value=48 stack=25
STWEnd dt=399
GoUnblock dt=5992 g=130 g_seq=6 stack=26
GCMarkAssistEnd dt=9