{name: "disablethp", value: &debug.disablethp},
	{name: "dontfreezetheworld", value: &debug.dontfreezetheworld},
	{name: "efence", value: &debug.efence},
	{name: "gccheckmark", value: &debug.gccheckmark},
	{name: "gcpacertrace", value: &debug.gcpacertrace},
	{name: "gcshrinkstackoff", value: &debug.gcshrinkstackoff},
	{name: "gcstoptheworld", value: &debug.gcstoptheworld},

	state and thus may hide problems.

	efence: setting efence=1 causes the allocator to run in a mode
	where each object is allocated on a unique page and addresses are
	never recycled.

	gccheckmark: setting gccheckmark=1 enables verification of the
	garbage collector's concurrent mark phase by performing a
	second mark pass while the world is stopped.  If the second
	pass finds a reachable object that was not found by concurrent

		// non-system stack to pick up the new addresses
		// before continuing.
	})

	var stwSwept bool
	systemstack(func() {
		work.heap2 = work.bytesMarked
		if debug.gccheckmark > 0 {
			// Run a full non-parallel, stop-the-world
			// mark using checkmark bits, to check that we
			// didn't forget to mark anything during the
			// concurrent mark process.
			startCheckmarks()
			gcResetMarkState()

// GC checkmarks
//
// In a concurrent garbage collector, one worries about failing to mark
// a live object due to mutations without write barriers or bugs in the
// collector implementation. As a sanity check, the GC has a 'checkmark'
// mode that retraverses the object graph with the world stopped, to make
// sure that everything that should be marked is marked.

package runtime

import (
	"internal/goarch"
	"internal/runtime/atomic"

	// Reads are done atomically to find spans containing specials
	// during marking.
	pageSpecials [pagesPerArena / 8]uint8

	// checkmarks stores the debug.gccheckmark state. It is only
	// used if debug.gccheckmark > 0.
	checkmarks *checkmarksMap

	// zeroedBase marks the first byte of the first page in this
	// arena which hasn't been used yet and is therefore already

	}
	mbits := span.markBitsForIndex(objIndex)

	if useCheckmark {
		if setCheckmark(obj, base, off, mbits) {
			// Already marked.
			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))

	ptrs := pp.wbBuf.buf[:n]

	// Poison the buffer to make extra sure nothing is enqueued
	// while we're processing the buffer.
	pp.wbBuf.next = 0

	if useCheckmark {
		// Slow path for checkmark mode.
		for _, ptr := range ptrs {
			shade(ptr)
		}
		pp.wbBuf.reset()
		return
	}

	// Mark all of the pointers in the buffer and record only the

// 115    40          DEMOTED cmd/compile/internal/abi.(*ABIParamAssignment).Offset     expand_calls.go:1679:14|6       panicPathAdj
// 76     -5n         PROMOTED runtime.persistentalloc   mcheckmark.go:48:45|3   inLoopAdj
// 201    0           --- PGO  unicode.DecodeRuneInString        utf8.go:312:30|1
// 7      -5          --- PGO  internal/abi.Name.DataChecked     type.go:625:22|0        inLoopAdj
//

	"·":                       "\u00b7",
	"𝔠":                             "\U0001d520",
	"ч":                            "\u0447",
	"✓":                           "\u2713",
	"✓":                       "\u2713",
	"χ":                             "\u03c7",
	"○":                             "\u25cb",
	"⧃":                            "\u29c3",

		"centerdot;":                       '\U000000B7',
		"cfr;":                             '\U0001D520',
		"chcy;":                            '\U00000447',
		"check;":                           '\U00002713',
		"checkmark;":                       '\U00002713',
		"chi;":                             '\U000003C7',
		"cir;":                             '\U000025CB',
		"cirE;":                            '\U000029C3',