}

// ConvIfaceTypeWord asserts that n is conversion to interface type,
// and returns an expression that yields the *runtime._type or
// *runtime.itab value necessary for implementing the conversion.
//
//   - *runtime._type for the destination type, for I2I conversions
//   - *runtime.itab, for T2I conversions
//   - *runtime._type for the source type, for T2E conversions
func ConvIfaceTypeWord(pos src.XPos, n *ir.ConvExpr) ir.Node {

	ptrType := v.Block.Func.Config.Types.BytePtr

	itab := v.Block.NewValue0(v.Pos, OpPhi, uintptrType)
	data := v.Block.NewValue0(v.Pos, OpPhi, ptrType)
	for _, a := range v.Args {
		itab.AddArg(a.Block.NewValue1(v.Pos, OpITab, uintptrType, a))
		data.AddArg(a.Block.NewValue1(v.Pos, OpIData, ptrType, a))
	}
	v.reset(OpIMake)
	v.AddArg(itab)
	v.AddArg(data)
}

func decomposeUser(f *Func) {

				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)

func decodetypeGcprogShlib(ctxt *Link, data []byte) uint64 {
	return decodeInuxi(ctxt.Arch, data[2*int32(ctxt.Arch.PtrSize)+8+1*int32(ctxt.Arch.PtrSize):], ctxt.Arch.PtrSize)
}

// decodeItabType returns the itab.Type field from an itab.
func decodeItabType(ldr *loader.Loader, arch *sys.Arch, symIdx loader.Sym) loader.Sym {
	relocs := ldr.Relocs(symIdx)
	return decodeRelocSym(ldr, symIdx, &relocs, int32(abi.ITabTypeOff(arch.PtrSize)))

		var itab *ir.AddrExpr
		if typ.IsEmptyInterface() {
			itab = reflectdata.TypePtrAt(base.Pos, val.Type())
		} else {
			itab = reflectdata.ITabAddrAt(base.Pos, val.Type(), typ)
		}

		// Create a copy of l to modify while we emit data.

		// Emit itab, advance offset.
		staticdata.InitAddr(l, loff, itab.X.(*ir.LinksymOffsetExpr).Linksym)

		// Emit data.

	//   c. at least one is a gcshape type.
	// For assignable but different non-empty interface types,
	// we want to recompute the itab. Recomputing the itab ensures
	// that itabs are unique (thus an interface with a compile-time
	// type I has an itab with interface type I).
	if types.Identical(src.Underlying(), dst.Underlying()) {
		if src.IsEmptyInterface() {
			// Conversion between two empty interfaces

# fields to python attributes in gdb.py isn't complete: you can't test
# for presence other than by trapping.


def is_iface(val):
	try:
		return str(val['tab'].type) == "struct runtime.itab *" and str(val['data'].type) == "void *"
	except gdb.error:
		pass


def is_eface(val):
	try:
		return str(val['_type'].type) == "struct runtime._type *" and str(val['data'].type) == "void *"

// walkDynamicDotType walks an ODYNAMICDOTTYPE or ODYNAMICDOTTYPE2 node.
func walkDynamicDotType(n *ir.DynamicTypeAssertExpr, init *ir.Nodes) ir.Node {
	n.X = walkExpr(n.X, init)
	n.RType = walkExpr(n.RType, init)
	n.ITab = walkExpr(n.ITab, init)
	// Convert to non-dynamic if we can.
	if n.RType != nil && n.RType.Op() == ir.OADDR {
		addr := n.RType.(*ir.AddrExpr)
		if addr.X.Op() == ir.OLINKSYMOFFSET {

	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: