}
	t.add(m)
}

// add adds the given itab to itab table t.
// itabLock must be held.
func (t *itabTableType) add(m *itab) {
	// See comment in find about the probe sequence.
	// Insert new itab in the first empty spot in the probe sequence.
	mask := t.size - 1
	h := itabHashFunc(m.Inter, m.Type) & mask
	for i := uintptr(1); ; i++ {
		p := (**itab)(add(unsafe.Pointer(&t.entries), h*goarch.PtrSize))
		m2 := *p

package abi

import "unsafe"

// The first word of every non-empty interface type contains an *ITab.
// It records the underlying concrete type (Type), the interface type it
// is implementing (Inter), and some ancillary information.
//
// allocated in non-garbage-collected memory
type ITab struct {
	Inter *InterfaceType
	Type  *Type
	Hash  uint32     // copy of Type.Hash. Used for type switches.

var V int = 1

var HasMask []string = []string{"hi"}

type HasProg struct {
	array [1024]*byte
}

type Dep struct {
	X int
}

func (d *Dep) Method() int {
	// This code below causes various go.itab.* symbols to be generated in
	// the shared library. Similar code in ../exe/exe.go results in
	// exercising https://golang.org/issues/17594
	reflect.TypeOf(os.Stdout).Elem()
	return 10
}

func F() int {

				rs := r.Sym()
				if d.ldr.IsItab(rs) {
					// This relocation can also point at an itab, in which case it
					// means "the Type field of that itab".
					rs = decodeItabType(d.ldr, d.ctxt.Arch, rs)
				}
				if !d.ldr.IsGoType(rs) && !d.ctxt.linkShared {
					panic(fmt.Sprintf("R_USEIFACE in %s references %s which is not a type or itab", d.ldr.SymName(symIdx), d.ldr.SymName(rs)))
				}
				if !d.ldr.AttrUsedInIface(rs) {

			s.startBlock(bOk)
			// nonempty -> empty
			// Need to load type from itab
			off := s.newValue1I(ssa.OpOffPtr, byteptr, rttype.ITab.OffsetOf("Type"), itab)
			s.vars[typVar] = s.load(byteptr, off)
			s.endBlock()

			// itab is nil, might as well use that as the nil result.
			s.startBlock(bFail)
			s.vars[typVar] = itab
			s.endBlock()

			// Merge point.
			bEnd := s.f.NewBlock(ssa.BlockPlain)

	case fint.Kind_&abi.KindMask == abi.Interface:
		ityp := (*interfacetype)(unsafe.Pointer(fint))
		if len(ityp.Methods) == 0 {
			// ok - satisfies empty interface
			goto okarg
		}
		if itab := assertE2I2(ityp, efaceOf(&obj)._type); itab != nil {
			goto okarg
		}
	}
	throw("runtime.SetFinalizer: cannot pass " + toRType(etyp).string() + " to finalizer " + toRType(ftyp).string())
okarg:

	lockRankSudog:           "sudog",
	lockRankTimers:          "timers",
	lockRankTimer:           "timer",
	lockRankNetpollInit:     "netpollInit",
	lockRankRoot:            "root",
	lockRankItab:            "itab",
	lockRankReflectOffs:     "reflectOffs",
	lockRankUserArenaState:  "userArenaState",
	lockRankTraceBuf:        "traceBuf",
	lockRankTraceStrings:    "traceStrings",
	lockRankFin:             "fin",

# Channels
NONE < notifyList;
hchan, notifyList < sudog;

hchan, pollDesc, wakeableSleep < timers;
timers, timerSend < timer < netpollInit;

# Semaphores
NONE < root;

# Itabs
NONE
< itab
< reflectOffs;

# User arena state
NONE < userArenaState;

# Tracing without a P uses a global trace buffer.
scavenge
# Above TRACEGLOBAL can emit a trace event without a P.
< TRACEGLOBAL

func panicnildottype(want *byte)
func typeAssert(s *byte, typ *byte) *byte

// interface switches
func interfaceSwitch(s *byte, t *byte) (int, *byte)

// interface equality. Type/itab pointers are already known to be equal, so
// we only need to pass one.
func ifaceeq(tab *uintptr, x, y unsafe.Pointer) (ret bool)
func efaceeq(typ *uintptr, x, y unsafe.Pointer) (ret bool)

	goCmd(t, "build", "-buildmode=plugin", "./iface_b")
	goCmd(t, "build", "-o", "iface.exe", "./iface")
	run(t, "./iface.exe")
}

func TestIssue18676(t *testing.T) {
	// make sure we don't add the same itab twice.
	// The buggy code hangs forever, so use a timeout to check for that.
	globalSkip(t)
	goCmd(t, "build", "-buildmode=plugin", "-o", "plugin.so", "./issue18676/plugin.go")