func initReflect(i *interpreter) {
	i.reflectPackage = &ssa.Package{
		Prog:    i.prog,
		Pkg:     reflectTypesPackage,
		Members: make(map[string]ssa.Member),
	}

	// Clobber the type-checker's notion of reflect.Value's
	// underlying type so that it more closely matches the fake one
	// (at least in the number of fields---we lie about the type of
	// the rtype field).
	//
	// We must ensure that calls to (ssa.Value).Type() return the
	// fake type so that correct "shape" is used when allocating
	// variables, making zero values, loading, and storing.
	//
	// TODO(adonovan): obviously this is a hack.  We need a cleaner
	// way to fake the reflect package (almost---DeepEqual is fine).
	// One approach would be not to even load its source code, but
	// provide fake source files.  This would guarantee that no bad
	// information leaks into other packages.
	if r := i.prog.ImportedPackage("reflect"); r != nil {
		rV := r.Pkg.Scope().Lookup("Value").Type().(*types.Named)

		// delete bodies of the old methods
		mset := i.prog.MethodSets.MethodSet(rV)
		for j := 0; j < mset.Len(); j++ {
			i.prog.MethodValue(mset.At(j)).Blocks = nil
		}

		tEface := types.NewInterface(nil, nil).Complete()
		rV.SetUnderlying(types.NewStruct([]*types.Var{
			types.NewField(token.NoPos, r.Pkg, "t", tEface, false), // a lie
			types.NewField(token.NoPos, r.Pkg, "v", tEface, false),
		}, nil))
	}

	i.rtypeMethods = methodSet{
		"Bits":      newMethod(i.reflectPackage, rtypeType, "Bits"),
		"Elem":      newMethod(i.reflectPackage, rtypeType, "Elem"),
		"Field":     newMethod(i.reflectPackage, rtypeType, "Field"),
		"In":        newMethod(i.reflectPackage, rtypeType, "In"),
		"Kind":      newMethod(i.reflectPackage, rtypeType, "Kind"),
		"NumField":  newMethod(i.reflectPackage, rtypeType, "NumField"),
		"NumIn":     newMethod(i.reflectPackage, rtypeType, "NumIn"),
		"NumMethod": newMethod(i.reflectPackage, rtypeType, "NumMethod"),
		"NumOut":    newMethod(i.reflectPackage, rtypeType, "NumOut"),
		"Out":       newMethod(i.reflectPackage, rtypeType, "Out"),
		"Size":      newMethod(i.reflectPackage, rtypeType, "Size"),
		"String":    newMethod(i.reflectPackage, rtypeType, "String"),
	}
	i.errorMethods = methodSet{
		"Error": newMethod(i.reflectPackage, errorType, "Error"),
	}
}

func optimalSize(str *types.Struct, sizes *gcSizes) int64 {
	nf := str.NumFields()
	fields := make([]*types.Var, nf)
	alignofs := make([]int64, nf)
	sizeofs := make([]int64, nf)
	for i := 0; i < nf; i++ {
		fields[i] = str.Field(i)
		ft := fields[i].Type()
		alignofs[i] = sizes.Alignof(ft)
		sizeofs[i] = sizes.Sizeof(ft)
	}
	sort.Sort(&byAlignAndSize{fields, alignofs, sizeofs})
	return sizes.Sizeof(types.NewStruct(fields, nil))
}

// StructType = "struct" "{" { Field } "}" .
func (p *parser) parseStructType(pkg *types.Package) types.Type {
	p.expectKeyword("struct")

	var fields []*types.Var
	var tags []string

	p.expect('{')
	for p.tok != '}' && p.tok != scanner.EOF {
		field, tag := p.parseField(pkg)
		p.expect(';')
		fields = append(fields, field)
		tags = append(tags, tag)
	}
	p.expect('}')

	return types.NewStruct(fields, tags)
}

// StructType = "struct" "{" [ FieldList ] "}" .
// FieldList  = Field { ";" Field } .
//
func (p *parser) parseStructType(parent *types.Package) types.Type {
	var fields []*types.Var
	var tags []string

	p.expectKeyword("struct")
	p.expect('{')
	for i := 0; p.tok != '}' && p.tok != scanner.EOF; i++ {
		if i > 0 {
			p.expect(';')
		}
		fld, tag := p.parseField(parent)
		if tag != "" && tags == nil {
			tags = make([]string, i)
		}
		if tags != nil {
			tags = append(tags, tag)
		}
		fields = append(fields, fld)
	}
	p.expect('}')

	return types.NewStruct(fields, tags)
}

// parent is the package which declared the type; parent == nil means
// the package currently imported. The parent package is needed for
// exported struct fields and interface methods which don't contain
// explicit package information in the export data.
func (p *importer) typ(parent *types.Package) types.Type {
	// if the type was seen before, i is its index (>= 0)
	i := p.tagOrIndex()
	if i >= 0 {
		return p.typList[i]
	}

	// otherwise, i is the type tag (< 0)
	switch i {
	case namedTag:
		// read type object
		name := p.string()
		parent = p.pkg()
		scope := parent.Scope()
		obj := scope.Lookup(name)

		// if the object doesn't exist yet, create and insert it
		if obj == nil {
			obj = types.NewTypeName(token.NoPos, parent, name, nil)
			scope.Insert(obj)
		}

		if _, ok := obj.(*types.TypeName); !ok {
			panic(fmt.Sprintf("pkg = %s, name = %s => %s", parent, name, obj))
		}

		// associate new named type with obj if it doesn't exist yet
		t0 := types.NewNamed(obj.(*types.TypeName), nil, nil)

		// but record the existing type, if any
		t := obj.Type().(*types.Named)
		p.record(t)

		// read underlying type
		t0.SetUnderlying(p.typ(parent))

		// interfaces don't have associated methods
		if _, ok := t0.Underlying().(*types.Interface); ok {
			return t
		}

		// read associated methods
		for i := p.int(); i > 0; i-- {
			name := p.string()
			recv, _ := p.paramList() // TODO(gri) do we need a full param list for the receiver?
			params, isddd := p.paramList()
			result, _ := p.paramList()
			p.int() // read and discard index of inlined function body
			sig := types.NewSignature(recv.At(0), params, result, isddd)
			t0.AddMethod(types.NewFunc(token.NoPos, parent, name, sig))
		}

		return t

	case arrayTag:
		t := new(types.Array)
		p.record(t)

		n := p.int64()
		*t = *types.NewArray(p.typ(parent), n)
		return t

	case sliceTag:
		t := new(types.Slice)
		p.record(t)

		*t = *types.NewSlice(p.typ(parent))
		return t

	case dddTag:
		t := new(dddSlice)
		p.record(t)

		t.elem = p.typ(parent)
		return t

	case structTag:
		t := new(types.Struct)
		p.record(t)

		n := p.int()
		fields := make([]*types.Var, n)
		tags := make([]string, n)
		for i := range fields {
			fields[i] = p.field(parent)
			tags[i] = p.string()
		}
		*t = *types.NewStruct(fields, tags)
		return t

	case pointerTag:
		t := new(types.Pointer)
		p.record(t)

		*t = *types.NewPointer(p.typ(parent))
		return t
//.........这里部分代码省略.........

func (p *importer) typ() types.Type {
	// if the type was seen before, i is its index (>= 0)
	i := p.int()
	if i >= 0 {
		return p.typList[i]
	}

	// otherwise, i is the type tag (< 0)
	switch i {
	case arrayTag:
		t := new(types.Array)
		p.record(t)

		n := p.int64()
		*t = *types.NewArray(p.typ(), n)
		return t

	case sliceTag:
		t := new(types.Slice)
		p.record(t)

		*t = *types.NewSlice(p.typ())
		return t

	case structTag:
		t := new(types.Struct)
		p.record(t)

		n := p.int()
		fields := make([]*types.Var, n)
		tags := make([]string, n)
		for i := range fields {
			fields[i] = p.field()
			tags[i] = p.string()
		}
		*t = *types.NewStruct(fields, tags)
		return t

	case pointerTag:
		t := new(types.Pointer)
		p.record(t)

		*t = *types.NewPointer(p.typ())
		return t

	case signatureTag:
		t := new(types.Signature)
		p.record(t)

		*t = *p.signature()
		return t

	case interfaceTag:
		// Create a dummy entry in the type list. This is safe because we
		// cannot expect the interface type to appear in a cycle, as any
		// such cycle must contain a named type which would have been
		// first defined earlier.
		n := len(p.typList)
		p.record(nil)

		// read embedded interfaces
		embeddeds := make([]*types.Named, p.int())
		for i := range embeddeds {
			embeddeds[i] = p.typ().(*types.Named)
		}

		// read methods
		methods := make([]*types.Func, p.int())
		for i := range methods {
			pkg, name := p.qualifiedName()
			methods[i] = types.NewFunc(token.NoPos, pkg, name, p.typ().(*types.Signature))
		}

		t := types.NewInterface(methods, embeddeds)
		p.typList[n] = t
		return t

	case mapTag:
		t := new(types.Map)
		p.record(t)

		*t = *types.NewMap(p.typ(), p.typ())
		return t

	case chanTag:
		t := new(types.Chan)
		p.record(t)

		*t = *types.NewChan(types.ChanDir(p.int()), p.typ())
		return t

	case namedTag:
		// read type object
		name := p.string()
		pkg := p.pkg()
		scope := pkg.Scope()
		obj := scope.Lookup(name)

		// if the object doesn't exist yet, create and insert it
		if obj == nil {
//.........这里部分代码省略.........