package runtime

import (
	"runtime/internal/atomic"
	"runtime/internal/sys"
	"unsafe"
)

const (
	fixedRootFinalizers = iota
	fixedRootFreeGStacks
	fixedRootCount

	rootBlockBytes = 256 << 10

	maxObletBytes = 128 << 10

	drainCheckThreshold = 100000

	pagesPerSpanRoot = 512
)

func gcMarkRootPrepare() {
	assertWorldStopped()

	work.nFlushCacheRoots = 0

	nBlocks := func(bytes uintptr) int {
		return int(divRoundUp(bytes, rootBlockBytes))
	}

	work.nDataRoots = 0
	work.nBSSRoots = 0

	for _, datap := range activeModules() {
		nDataRoots := nBlocks(datap.edata - datap.data)
		if nDataRoots > work.nDataRoots {
			work.nDataRoots = nDataRoots
		}
	}

	for _, datap := range activeModules() {
		nBSSRoots := nBlocks(datap.ebss - datap.bss)
		if nBSSRoots > work.nBSSRoots {
			work.nBSSRoots = nBSSRoots
		}
	}

	mheap_.markArenas = mheap_.allArenas[:len(mheap_.allArenas):len(mheap_.allArenas)]
	work.nSpanRoots = len(mheap_.markArenas) * (pagesPerArena / pagesPerSpanRoot)

	work.nStackRoots = int(atomic.Loaduintptr(&allglen))

	work.markrootNext = 0
	work.markrootJobs = uint32(fixedRootCount + work.nFlushCacheRoots + work.nDataRoots + work.nBSSRoots + work.nSpanRoots + work.nStackRoots)
}

func gcMarkRootCheck() {
	if work.markrootNext < work.markrootJobs {
		print(work.markrootNext, " of ", work.markrootJobs, " markroot jobs done\n")
		throw("left over markroot jobs")
	}

	var gp *g
	for i := 0; i < work.nStackRoots; i++ {
		gp = allgs[i]
		if !gp.gcscandone {
			goto fail
		}
	}
	unlock(&allglock)
	return

fail:
	println("gp", gp, "goid", gp.goid,
		"status", readgstatus(gp),
		"gcscandone", gp.gcscandone)
	throw("scan missed a g")
}

var oneptrmask = [...]uint8{1}

	baseFlushCache := uint32(fixedRootCount)
	baseData := baseFlushCache + uint32(work.nFlushCacheRoots)
	baseBSS := baseData + uint32(work.nDataRoots)
	baseSpans := baseBSS + uint32(work.nBSSRoots)
	baseStacks := baseSpans + uint32(work.nSpanRoots)
	end := baseStacks + uint32(work.nStackRoots)

	switch {
	case baseFlushCache <= i && i < baseData:
		flushmcache(int(i - baseFlushCache))

	case baseData <= i && i < baseBSS:
		for _, datap := range activeModules() {
			markrootBlock(datap.data, datap.edata-datap.data, datap.gcdatamask.bytedata, gcw, int(i-baseData))
		}

	case baseBSS <= i && i < baseSpans:
		for _, datap := range activeModules() {
			markrootBlock(datap.bss, datap.ebss-datap.bss, datap.gcbssmask.bytedata, gcw, int(i-baseBSS))
		}

	case i == fixedRootFinalizers:
		for fb := allfin; fb != nil; fb = fb.alllink {
			cnt := uintptr(atomic.Load(&fb.cnt))
			scanblock(uintptr(unsafe.Pointer(&fb.fin[0])), cnt*unsafe.Sizeof(fb.fin[0]), &finptrmask[0], gcw, nil)
		}

		systemstack(markrootFreeGStacks)

		markrootSpans(gcw, int(i-baseSpans))

		var gp *g
		if baseStacks <= i && i < end {
			gp = allgs[i-baseStacks]
		} else {
			throw("markroot: bad index")
		}

		status := readgstatus(gp) // We are not in a scan state
		if (status == _Gwaiting || status == _Gsyscall) && gp.waitsince == 0 {
			gp.waitsince = work.tstart
		}

			userG := getg().m.curg
			selfScan := gp == userG && readgstatus(userG) == _Grunning
			if selfScan {
				casgstatus(userG, _Grunning, _Gwaiting)
				userG.waitreason = waitReasonGarbageCollectionScan
			}

			stopped := suspendG(gp)
			if stopped.dead {
				gp.gcscandone = true
				return
			}
			if gp.gcscandone {
				throw("g already scanned")
			}
			scanstack(gp, gcw)
			gp.gcscandone = true
			resumeG(stopped)

			if selfScan {
				casgstatus(userG, _Gwaiting, _Grunning)
			}
		})
	}
}

func markrootBlock(b0, n0 uintptr, ptrmask0 *uint8, gcw *gcWork, shard int) {

		throw("rootBlockBytes must be a multiple of 8*ptrSize")
	}

	off := uintptr(shard) * rootBlockBytes
	if off >= n0 {
		return
	}
	b := b0 + off
	ptrmask := (*uint8)(add(unsafe.Pointer(ptrmask0), uintptr(shard)*(rootBlockBytes/(8*sys.PtrSize))))
	n := uintptr(rootBlockBytes)
	if off+n > n0 {
		n = n0 - off
	}

	scanblock(b, n, ptrmask, gcw, nil)
}

	lock(&sched.gFree.lock)
	list := sched.gFree.stack
	sched.gFree.stack = gList{}
	unlock(&sched.gFree.lock)
	if list.empty() {
		return
	}

	q := gQueue{list.head, list.head}
	for gp := list.head.ptr(); gp != nil; gp = gp.schedlink.ptr() {
		stackfree(gp.stack)
		gp.stack.lo = 0

		q.tail.set(gp)
	}

	lock(&sched.gFree.lock)
	sched.gFree.noStack.pushAll(q)
	unlock(&sched.gFree.lock)
}

	sg := mheap_.sweepgen

	ai := mheap_.markArenas[shard/(pagesPerArena/pagesPerSpanRoot)]
	ha := mheap_.arenas[ai.l1()][ai.l2()]
	arenaPage := uint(uintptr(shard) * pagesPerSpanRoot % pagesPerArena)

	specialsbits := ha.pageSpecials[arenaPage/8:]
	specialsbits = specialsbits[:pagesPerSpanRoot/8]

		specials := atomic.Load8(&specialsbits[i])
		if specials == 0 {
			continue
		}
		for j := uint(0); j < 8; j++ {
			if specials&(1<<j) == 0 {
				continue

			s := ha.spans[arenaPage+uint(i)*8+j]

			if state := s.state.get(); state != mSpanInUse {
				print("s.state = ", state, "\n")
				throw("non in-use span found with specials bit set")

				print("sweep ", s.sweepgen, " ", sg, "\n")
				throw("gc: unswept span")
			}

			lock(&s.speciallock)
			for sp := s.specials; sp != nil; sp = sp.next {
				if sp.kind != _KindSpecialFinalizer {
					continue

				p := s.base() + uintptr(spf.special.offset)/s.elemsize*s.elemsize

				scanobject(p, gcw)

				scanblock(uintptr(unsafe.Pointer(&spf.fn)), sys.PtrSize, &oneptrmask[0], gcw, nil)
			}
			unlock(&s.speciallock)
		}
	}
}

	if getg() == gp.m.g0 {
		return
	}
	if mp := getg().m; mp.locks > 0 || mp.preemptoff != "" {
		return
	}

	traced := false

	assistWorkPerByte := float64frombits(atomic.Load64(&gcController.assistWorkPerByte))
	assistBytesPerWork := float64frombits(atomic.Load64(&gcController.assistBytesPerWork))
	debtBytes := -gp.gcAssistBytes
	scanWork := int64(assistWorkPerByte * float64(debtBytes))
	if scanWork < gcOverAssistWork {
		scanWork = gcOverAssistWork
		debtBytes = int64(assistBytesPerWork * float64(scanWork))
	}

	bgScanCredit := atomic.Loadint64(&gcController.bgScanCredit)
	stolen := int64(0)
	if bgScanCredit > 0 {
		if bgScanCredit < scanWork {
			stolen = bgScanCredit
			gp.gcAssistBytes += 1 + int64(assistBytesPerWork*float64(stolen))
		} else {
			stolen = scanWork
			gp.gcAssistBytes += debtBytes
		}
		atomic.Xaddint64(&gcController.bgScanCredit, -stolen)

		scanWork -= stolen

			if traced {
				traceGCMarkAssistDone()
			}
			return
		}
	}

	if trace.enabled && !traced {
		traced = true
		traceGCMarkAssistStart()
	}

	systemstack(func() {

	})

	completed := gp.param != nil
	gp.param = nil
	if completed {
		gcMarkDone()
	}

		if gp.preempt {
			Gosched()
			goto retry
		}

		if !gcParkAssist() {
			goto retry
		}

	}
	if traced {
		traceGCMarkAssistDone()
	}
}

	gp.param = nil

		gp.gcAssistBytes = 0
		return

	startTime := nanotime()

	decnwait := atomic.Xadd(&work.nwait, -1)
	if decnwait == work.nproc {
		println("runtime: work.nwait =", decnwait, "work.nproc=", work.nproc)
		throw("nwait > work.nprocs")
	}

	casgstatus(gp, _Grunning, _Gwaiting)
	gp.waitreason = waitReasonGCAssistMarking

	gcw := &getg().m.p.ptr().gcw
	workDone := gcDrainN(gcw, scanWork)

	casgstatus(gp, _Gwaiting, _Grunning)

	assistBytesPerWork := float64frombits(atomic.Load64(&gcController.assistBytesPerWork))
	gp.gcAssistBytes += 1 + int64(assistBytesPerWork*float64(workDone))

	incnwait := atomic.Xadd(&work.nwait, +1)
	if incnwait > work.nproc {
		println("runtime: work.nwait=", incnwait,
			"work.nproc=", work.nproc)
		throw("work.nwait > work.nproc")
	}

		gp.param = unsafe.Pointer(gp)
	}
	duration := nanotime() - startTime
	_p_ := gp.m.p.ptr()
	_p_.gcAssistTime += duration
	if _p_.gcAssistTime > gcAssistTimeSlack {
		atomic.Xaddint64(&gcController.assistTime, _p_.gcAssistTime)
		_p_.gcAssistTime = 0
	}
}

func gcWakeAllAssists() {
	lock(&work.assistQueue.lock)
	list := work.assistQueue.q.popList()
	injectglist(&list)
	unlock(&work.assistQueue.lock)
}

func gcParkAssist() bool {

	if atomic.Load(&gcBlackenEnabled) == 0 {
		unlock(&work.assistQueue.lock)
		return true
	}

	gp := getg()
	oldList := work.assistQueue.q
	work.assistQueue.q.pushBack(gp)

	if atomic.Loadint64(&gcController.bgScanCredit) > 0 {
		work.assistQueue.q = oldList
		if oldList.tail != 0 {
			oldList.tail.ptr().schedlink.set(nil)
		}
		unlock(&work.assistQueue.lock)
		return false

	goparkunlock(&work.assistQueue.lock, waitReasonGCAssistWait, traceEvGoBlockGC, 2)
	return true
}

func gcFlushBgCredit(scanWork int64) {

		atomic.Xaddint64(&gcController.bgScanCredit, scanWork)
		return
	}

	assistBytesPerWork := float64frombits(atomic.Load64(&gcController.assistBytesPerWork))
	scanBytes := int64(float64(scanWork) * assistBytesPerWork)

	lock(&work.assistQueue.lock)
	for !work.assistQueue.q.empty() && scanBytes > 0 {

			scanBytes += gp.gcAssistBytes

			ready(gp, 0, false)

			gp.gcAssistBytes += scanBytes

			work.assistQueue.q.pushBack(gp)
			break
		}
	}

		assistWorkPerByte := float64frombits(atomic.Load64(&gcController.assistWorkPerByte))
		scanWork = int64(float64(scanBytes) * assistWorkPerByte)
		atomic.Xaddint64(&gcController.bgScanCredit, scanWork)
	}
	unlock(&work.assistQueue.lock)
}

func scanstack(gp *g, gcw *gcWork) {
	if readgstatus(gp)&_Gscan == 0 {
		print("runtime:scanstack: gp=", gp, ", goid=", gp.goid, ", gp->atomicstatus=", hex(readgstatus(gp)), "\n")
		throw("scanstack - bad status")
	}

	switch readgstatus(gp) &^ _Gscan {
	default:
		print("runtime: gp=", gp, ", goid=", gp.goid, ", gp->atomicstatus=", readgstatus(gp), "\n")
		throw("mark - bad status")
	case _Gdead:
		return
	case _Grunning:
		print("runtime: gp=", gp, ", goid=", gp.goid, ", gp->atomicstatus=", readgstatus(gp), "\n")
		throw("scanstack: goroutine not stopped")

	}

	if gp == getg() {
		throw("can't scan our own stack")
	}

		shrinkstack(gp)

		gp.preemptShrink = true
	}

	var state stackScanState
	state.stack = gp.stack

	if stackTraceDebug {
		println("stack trace goroutine", gp.goid)
	}

	if debugScanConservative && gp.asyncSafePoint {
		print("scanning async preempted goroutine ", gp.goid, " stack [", hex(gp.stack.lo), ",", hex(gp.stack.hi), ")\n")
	}

	if gp.sched.ctxt != nil {
		scanblock(uintptr(unsafe.Pointer(&gp.sched.ctxt)), sys.PtrSize, &oneptrmask[0], gcw, &state)
	}

	scanframe := func(frame *stkframe, unused unsafe.Pointer) bool {
		scanframeworker(frame, &state, gcw)
		return true
	}
	gentraceback(^uintptr(0), ^uintptr(0), 0, gp, 0, nil, 0x7fffffff, scanframe, nil, 0)

	tracebackdefers(gp, scanframe, nil)

	for d := gp._defer; d != nil; d = d.link {

			scanblock(uintptr(unsafe.Pointer(&d.fn)), sys.PtrSize, &oneptrmask[0], gcw, &state)
		}

			scanblock(uintptr(unsafe.Pointer(&d.link)), sys.PtrSize, &oneptrmask[0], gcw, &state)

		if d.heap {
			scanblock(uintptr(unsafe.Pointer(&d)), sys.PtrSize, &oneptrmask[0], gcw, &state)
		}
	}

		state.putPtr(uintptr(unsafe.Pointer(gp._panic)), false)
	}

	state.buildIndex()
	for {
		p, conservative := state.getPtr()
		if p == 0 {
			break
		}
		obj := state.findObject(p)
		if obj == nil {
			continue
		}
		t := obj.typ

			continue
		}
		obj.setType(nil) // Don't scan it again.
		if stackTraceDebug {
			printlock()
			print("  live stkobj at", hex(state.stack.lo+uintptr(obj.off)), "of type", t.string())
			if conservative {
				print(" (conservative)")
			}
			println()
			printunlock()
		}
		gcdata := t.gcdata
		var s *mspan

			s = materializeGCProg(t.ptrdata, gcdata)
			gcdata = (*byte)(unsafe.Pointer(s.startAddr))
		}

		b := state.stack.lo + uintptr(obj.off)
		if conservative {
			scanConservative(b, t.ptrdata, gcdata, gcw, &state)
		} else {
			scanblock(b, t.ptrdata, gcdata, gcw, &state)
		}

		if s != nil {
			dematerializeGCProg(s)
		}
	}

	for state.head != nil {
		x := state.head
		state.head = x.next
		if stackTraceDebug {
			for i := 0; i < x.nobj; i++ {
				obj := &x.obj[i]
				if obj.typ == nil { // reachable
					continue
				}

			}
		}
		x.nobj = 0
		putempty((*workbuf)(unsafe.Pointer(x)))
	}
	if state.buf != nil || state.cbuf != nil || state.freeBuf != nil {
		throw("remaining pointer buffers")
	}
}

func scanframeworker(frame *stkframe, state *stackScanState, gcw *gcWork) {
	if _DebugGC > 1 && frame.continpc != 0 {
		print("scanframe ", funcname(frame.fn), "\n")
	}

	isAsyncPreempt := frame.fn.valid() && frame.fn.funcID == funcID_asyncPreempt
	isDebugCall := frame.fn.valid() && frame.fn.funcID == funcID_debugCallV1
	if state.conservative || isAsyncPreempt || isDebugCall {
		if debugScanConservative {
			println("conservatively scanning function", funcname(frame.fn), "at PC", hex(frame.continpc))
		}

		if frame.varp != 0 {
			size := frame.varp - frame.sp
			if size > 0 {
				scanConservative(frame.sp, size, nil, gcw, state)
			}
		}

			scanConservative(frame.argp, frame.arglen, nil, gcw, state)
		}

			state.conservative = true

			state.conservative = false
		}
		return
	}

	locals, args, objs := getStackMap(frame, &state.cache, false)

	if locals.n > 0 {
		size := uintptr(locals.n) * sys.PtrSize
		scanblock(frame.varp-size, size, locals.bytedata, gcw, state)
	}

	if args.n > 0 {
		scanblock(frame.argp, uintptr(args.n)*sys.PtrSize, args.bytedata, gcw, state)
	}

		for _, obj := range objs {
			off := obj.off
			base := frame.varp // locals base pointer
			if off >= 0 {
				base = frame.argp // arguments and return values base pointer
			}
			ptr := base + uintptr(off)

				continue
			}
			if stackTraceDebug {
				println("stkobj at", hex(ptr), "of type", obj.typ.string())
			}
			state.addObject(ptr, obj.typ)
		}
	}
}

type gcDrainFlags int

const (
	gcDrainUntilPreempt gcDrainFlags = 1 << iota
	gcDrainFlushBgCredit
	gcDrainIdle
	gcDrainFractional
)

func gcDrain(gcw *gcWork, flags gcDrainFlags) {
	if !writeBarrier.needed {
		throw("gcDrain phase incorrect")
	}

	gp := getg().m.curg
	preemptible := flags&gcDrainUntilPreempt != 0
	flushBgCredit := flags&gcDrainFlushBgCredit != 0
	idle := flags&gcDrainIdle != 0

	initScanWork := gcw.scanWork

	checkWork := int64(1<<63 - 1)
	var check func() bool
	if flags&(gcDrainIdle|gcDrainFractional) != 0 {
		checkWork = initScanWork + drainCheckThreshold
		if idle {
			check = pollWork
		} else if flags&gcDrainFractional != 0 {
			check = pollFractionalWorkerExit
		}
	}

		for !(gp.preempt && (preemptible || atomic.Load(&sched.gcwaiting) != 0)) {
			job := atomic.Xadd(&work.markrootNext, +1) - 1
			if job >= work.markrootJobs {
				break
			}
			markroot(gcw, job)
			if check != nil && check() {
				goto done
			}
		}
	}

		if work.full == 0 {
			gcw.balance()
		}

		b := gcw.tryGetFast()
		if b == 0 {
			b = gcw.tryGet()

				wbBufFlush(nil, 0)
				b = gcw.tryGet()
			}
		}

			break
		}
		scanobject(b, gcw)

		if gcw.scanWork >= gcCreditSlack {
			atomic.Xaddint64(&gcController.scanWork, gcw.scanWork)
			if flushBgCredit {
				gcFlushBgCredit(gcw.scanWork - initScanWork)
				initScanWork = 0
			}
			checkWork -= gcw.scanWork
			gcw.scanWork = 0

			if checkWork <= 0 {
				checkWork += drainCheckThreshold
				if check != nil && check() {
					break
				}
			}
		}
	}

	if gcw.scanWork > 0 {
		atomic.Xaddint64(&gcController.scanWork, gcw.scanWork)
		if flushBgCredit {
			gcFlushBgCredit(gcw.scanWork - initScanWork)
		}
		gcw.scanWork = 0
	}
}

func gcDrainN(gcw *gcWork, scanWork int64) int64 {
	if !writeBarrier.needed {
		throw("gcDrainN phase incorrect")
	}

	workFlushed := -gcw.scanWork

	gp := getg().m.curg

		if work.full == 0 {
			gcw.balance()
		}

		b := gcw.tryGetFast()
		if b == 0 {
			b = gcw.tryGet()

				wbBufFlush(nil, 0)
				b = gcw.tryGet()
			}
		}

			if work.markrootNext < work.markrootJobs {
				job := atomic.Xadd(&work.markrootNext, +1) - 1
				if job < work.markrootJobs {
					markroot(gcw, job)
					continue
				}

			break
		}
		scanobject(b, gcw)

		if gcw.scanWork >= gcCreditSlack {
			atomic.Xaddint64(&gcController.scanWork, gcw.scanWork)
			workFlushed += gcw.scanWork
			gcw.scanWork = 0
		}
	}

	return workFlushed + gcw.scanWork
}

	b := b0
	n := n0

		bits := uint32(*addb(ptrmask, i/(sys.PtrSize*8)))
		if bits == 0 {
			i += sys.PtrSize * 8
			continue
		}
		for j := 0; j < 8 && i < n; j++ {

				p := *(*uintptr)(unsafe.Pointer(b + i))
				if p != 0 {
					if obj, span, objIndex := findObject(p, b, i); obj != 0 {
						greyobject(obj, b, i, span, gcw, objIndex)
					} else if stk != nil && p >= stk.stack.lo && p < stk.stack.hi {
						stk.putPtr(p, false)
					}
				}
			}
			bits >>= 1
			i += sys.PtrSize
		}
	}
}

	hbits := heapBitsForAddr(b)
	s := spanOfUnchecked(b)
	n := s.elemsize
	if n == 0 {
		throw("scanobject n == 0")
	}

				gcw.bytesMarked += uint64(n)
				return
			}

			for oblet := b + maxObletBytes; oblet < s.base()+s.elemsize; oblet += maxObletBytes {
				if !gcw.putFast(oblet) {
					gcw.put(oblet)
				}
			}
		}

		n = s.base() + s.elemsize - b
		if n > maxObletBytes {
			n = maxObletBytes
		}
	}

	var i uintptr

			hbits = hbits.next()

		bits := hbits.bits()
		if bits&bitScan == 0 {
			break // no more pointers in this object
		}
		if bits&bitPointer == 0 {
			continue // not a pointer
		}

		obj := *(*uintptr)(unsafe.Pointer(b + i))

			if obj, span, objIndex := findObject(obj, b, i); obj != 0 {
				greyobject(obj, b, i, span, gcw, objIndex)
			}
		}
	}
	gcw.bytesMarked += uint64(n)
	gcw.scanWork += int64(i)
}

func scanConservative(b, n uintptr, ptrmask *uint8, gcw *gcWork, state *stackScanState) {
	if debugScanConservative {
		printlock()
		print("conservatively scanning [", hex(b), ",", hex(b+n), ")\n")
		hexdumpWords(b, b+n, func(p uintptr) byte {
			if ptrmask != nil {
				word := (p - b) / sys.PtrSize
				bits := *addb(ptrmask, word/8)
				if (bits>>(word%8))&1 == 0 {
					return '$'
				}
			}

			val := *(*uintptr)(unsafe.Pointer(p))
			if state != nil && state.stack.lo <= val && val < state.stack.hi {
				return '@'
			}

			span := spanOfHeap(val)
			if span == nil {
				return ' '
			}
			idx := span.objIndex(val)
			if span.isFree(idx) {
				return ' '
			}
			return '*'
		})
		printunlock()
	}

	for i := uintptr(0); i < n; i += sys.PtrSize {
		if ptrmask != nil {
			word := i / sys.PtrSize
			bits := *addb(ptrmask, word/8)

				if i%(sys.PtrSize*8) != 0 {
					throw("misaligned mask")
				}
				i += sys.PtrSize*8 - sys.PtrSize
				continue
			}
			if (bits>>(word%8))&1 == 0 {
				continue
			}
		}

		val := *(*uintptr)(unsafe.Pointer(b + i))

			state.putPtr(val, true)
			continue
		}

		span := spanOfHeap(val)
		if span == nil {
			continue
		}

		idx := span.objIndex(val)
		if span.isFree(idx) {
			continue
		}

		obj := span.base() + idx*span.elemsize
		greyobject(obj, b, i, span, gcw, idx)
	}
}

func shade(b uintptr) {
	if obj, span, objIndex := findObject(b, 0, 0); obj != 0 {
		gcw := &getg().m.p.ptr().gcw
		greyobject(obj, 0, 0, span, gcw, objIndex)
	}
}

	if obj&(sys.PtrSize-1) != 0 {
		throw("greyobject: obj not pointer-aligned")
	}
	mbits := span.markBitsForIndex(objIndex)

	if useCheckmark {

			return
		}
	} else {
		if debug.gccheckmark > 0 && span.isFree(objIndex) {
			print("runtime: marking free object ", hex(obj), " found at *(", hex(base), "+", hex(off), ")\n")
			gcDumpObject("base", base, off)
			gcDumpObject("obj", obj, ^uintptr(0))
			getg().m.traceback = 2
			throw("marking free object")
		}

		if mbits.isMarked() {
			return
		}
		mbits.setMarked()

		arena, pageIdx, pageMask := pageIndexOf(span.base())
		if arena.pageMarks[pageIdx]&pageMask == 0 {
			atomic.Or8(&arena.pageMarks[pageIdx], pageMask)
		}

		if span.spanclass.noscan() {
			gcw.bytesMarked += uint64(span.elemsize)
			return
		}
	}

	if !gcw.putFast(obj) {
		gcw.put(obj)
	}
}

func gcDumpObject(label string, obj, off uintptr) {
	s := spanOf(obj)
	print(label, "=", hex(obj))
	if s == nil {
		print(" s=nil\n")
		return
	}
	print(" s.base()=", hex(s.base()), " s.limit=", hex(s.limit), " s.spanclass=", s.spanclass, " s.elemsize=", s.elemsize, " s.state=")
	if state := s.state.get(); 0 <= state && int(state) < len(mSpanStateNames) {
		print(mSpanStateNames[state], "\n")
	} else {
		print("unknown(", state, ")\n")
	}

	skipped := false
	size := s.elemsize

		size = off + sys.PtrSize
	}

		if !(i < 128*sys.PtrSize || off-16*sys.PtrSize < i && i < off+16*sys.PtrSize) {
			skipped = true
			continue
		}
		if skipped {
			print(" ...\n")
			skipped = false
		}
		print(" *(", label, "+", i, ") = ", hex(*(*uintptr)(unsafe.Pointer(obj + i))))
		if i == off {
			print(" <==")
		}
		print("\n")
	}
	if skipped {
		print(" ...\n")
	}
}

func gcmarknewobject(span *mspan, obj, size, scanSize uintptr) {
	if useCheckmark { // The world should be stopped so this should not happen.
		throw("gcmarknewobject called while doing checkmark")
	}

	objIndex := span.objIndex(obj)
	span.markBitsForIndex(objIndex).setMarked()

	arena, pageIdx, pageMask := pageIndexOf(span.base())
	if arena.pageMarks[pageIdx]&pageMask == 0 {
		atomic.Or8(&arena.pageMarks[pageIdx], pageMask)
	}

	gcw := &getg().m.p.ptr().gcw
	gcw.bytesMarked += uint64(size)
	gcw.scanWork += int64(scanSize)
}

func gcMarkTinyAllocs() {
	assertWorldStopped()

	for _, p := range allp {
		c := p.mcache
		if c == nil || c.tiny == 0 {
			continue
		}
		_, span, objIndex := findObject(c.tiny, 0, 0)
		gcw := &p.gcw
		greyobject(c.tiny, 0, 0, span, gcw, objIndex)
	}