// Number of roots of various root types. Set by gcMarkRootPrepare.
	//
	// nStackRoots == len(stackRoots), but we have nStackRoots for
	// consistency.
	nDataRoots, nBSSRoots, nSpanRoots, nStackRoots int

	// Base indexes of each root type. Set by gcMarkRootPrepare.
	baseData, baseBSS, baseSpans, baseStacks, baseEnd uint32

	// stackRoots is a snapshot of all of the Gs that existed