mu   mutex
	span mSpanList
}

// Global pool of large stack spans.
var stackLarge struct {
	lock mutex
	free [heapAddrBits - pageShift]mSpanList // free lists by log_2(s.npages)
}

func stackinit() {
	if _StackCacheSize&_PageMask != 0 {
		throw("cache size must be a multiple of page size")
	}
	for i := range stackpool {
		stackpool[i].item.span.init()
		lockInit(&stackpool[i].item.mu, lockRankStackpool)

// is a nil defer.

package main

func stackit(n int) {
	if n == 0 {
		return
	}
	stackit(n - 1)
}

func main() {
	defer func() {
		// catch & ignore panic from nil defer below
		err := recover()
		if err == nil {
			panic("defer of nil func didn't panic")
		}
	}()
	defer ((func())(nil))()
	stackit(1000)

            "lineWidth": 1,
            "pointSize": 5,
            "scaleDistribution": {
              "type": "linear"
            },
            "showPoints": "never",
            "spanNulls": false,
            "stacking": {
              "group": "A",
              "mode": "none"
            },
            "thresholdsStyle": {
              "mode": "off"
            }
          },
          "mappings": [],

            "lineWidth": 1,
            "pointSize": 5,
            "scaleDistribution": {
              "type": "linear"
            },
            "showPoints": "never",
            "spanNulls": false,
            "stacking": {
              "group": "A",
              "mode": "none"
            },
            "thresholdsStyle": {
              "mode": "off"
            }
          },
          "mappings": [],

            "pointSize": 5,
            "scaleDistribution": {
              "type": "linear"
            },
            "showPoints": "never",
            "spanNulls": false,
            "stacking": {
              "group": "A",
              "mode": "none"
            },
            "thresholdsStyle": {
              "mode": "off"
            }
          },
          "mappings": [],

            "lineWidth": 1,
            "pointSize": 5,
            "scaleDistribution": {
              "type": "linear"
            },
            "showPoints": "never",
            "spanNulls": false,
            "stacking": {
              "group": "A",
              "mode": "none"
            },
            "thresholdsStyle": {
              "mode": "off"
            }
          },
          "links": [],

            "pointSize": 5,
            "scaleDistribution": {
              "type": "linear"
            },
            "showPoints": "never",
            "spanNulls": false,
            "stacking": {
              "group": "A",
              "mode": "none"
            },
            "thresholdsStyle": {
              "mode": "off"
            }
          },
          "mappings": [],

            "pointSize": 5,
            "scaleDistribution": {
              "type": "linear"
            },
            "showPoints": "never",
            "spanNulls": true,
            "stacking": {
              "group": "A",
              "mode": "none"
            },
            "thresholdsStyle": {
              "mode": "off"
            }
          },
          "mappings": [],

            "pointSize": 5,
            "scaleDistribution": {
              "type": "linear"
            },
            "showPoints": "never",
            "spanNulls": false,
            "stacking": {
              "group": "A",
              "mode": "none"
            },
            "thresholdsStyle": {
              "mode": "off"
            }
          },
          "links": [],

	type stackEnt struct {
		path   string
		start  int
		offset int
		prev   *stackEnt
	}

	noPath := &stackEnt{"", 0, 0, nil}
	tos := noPath

pathloop:
	for _, s := range o.Paths {
		val := int(s.Value)
		switch {
		case val > aline:
			break pathloop

		case val == 1:
			// Start a new stack
			tos = &stackEnt{s.Name, val, 0, noPath}