goto walkloop
			}
		}
	}
}

// A shadowRange encodes a set of byte offsets [lo():hi()] from
// a given pointer that will be written to later in the block.
// A zero shadowRange encodes an empty shadowed range (and so
// does a -1 shadowRange, which is what sparsemap.get returns
// on a failed lookup).
type shadowRange int32

func (sr shadowRange) lo() int64 {
	return int64(sr & 0xffff)
}