Merge pull request #382 from xushiwei/q

patch reflect: Append/Index; Int fix

_demo/reflect/reflect.go

@@ -0,0 +1,13 @@
+package main
+
+import "reflect"
+
+func main() {
+	tyIntSlice := reflect.SliceOf(reflect.TypeOf(0))
+	v := reflect.Zero(tyIntSlice)
+	v = reflect.Append(v, reflect.ValueOf(1), reflect.ValueOf(2), reflect.ValueOf(3))
+	for i, n := 0, v.Len(); i < n; i++ {
+		item := v.Index(i)
+		println(item.Int())
+	}
+}

internal/abi/type.go

@@ -440,21 +440,21 @@ func (t *Type) Len() int {
 // Elem returns the element type for t if t is an array, channel, map, pointer, or slice, otherwise nil.
 func (t *Type) Elem() *Type {
 	switch t.Kind() {
-	case Array:
-		tt := (*ArrayType)(unsafe.Pointer(t))
-		return tt.Elem
-	case Chan:
-		tt := (*ChanType)(unsafe.Pointer(t))
-		return tt.Elem
-	case Map:
-		tt := (*MapType)(unsafe.Pointer(t))
-		return tt.Elem
 	case Pointer:
 		tt := (*PtrType)(unsafe.Pointer(t))
 		return tt.Elem
 	case Slice:
 		tt := (*SliceType)(unsafe.Pointer(t))
 		return tt.Elem
+	case Map:
+		tt := (*MapType)(unsafe.Pointer(t))
+		return tt.Elem
+	case Array:
+		tt := (*ArrayType)(unsafe.Pointer(t))
+		return tt.Elem
+	case Chan:
+		tt := (*ChanType)(unsafe.Pointer(t))
+		return tt.Elem
 	}
 	return nil
 }

internal/lib/reflect/makefunc.go

@@ -0,0 +1,182 @@
+// Copyright 2012 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// MakeFunc implementation.
+
+package reflect
+
+/*
+import (
+	"unsafe"
+)
+
+// makeFuncImpl is the closure value implementing the function
+// returned by MakeFunc.
+// The first three words of this type must be kept in sync with
+// methodValue and runtime.reflectMethodValue.
+// Any changes should be reflected in all three.
+type makeFuncImpl struct {
+	makeFuncCtxt
+	ftyp *funcType
+	fn   func([]Value) []Value
+}
+
+// MakeFunc returns a new function of the given Type
+// that wraps the function fn. When called, that new function
+// does the following:
+//
+//   - converts its arguments to a slice of Values.
+//   - runs results := fn(args).
+//   - returns the results as a slice of Values, one per formal result.
+//
+// The implementation fn can assume that the argument Value slice
+// has the number and type of arguments given by typ.
+// If typ describes a variadic function, the final Value is itself
+// a slice representing the variadic arguments, as in the
+// body of a variadic function. The result Value slice returned by fn
+// must have the number and type of results given by typ.
+//
+// The Value.Call method allows the caller to invoke a typed function
+// in terms of Values; in contrast, MakeFunc allows the caller to implement
+// a typed function in terms of Values.
+//
+// The Examples section of the documentation includes an illustration
+// of how to use MakeFunc to build a swap function for different types.
+func MakeFunc(typ Type, fn func(args []Value) (results []Value)) Value {
+	if typ.Kind() != Func {
+		panic("reflect: call of MakeFunc with non-Func type")
+	}
+
+	t := typ.common()
+	ftyp := (*funcType)(unsafe.Pointer(t))
+
+	code := abi.FuncPCABI0(makeFuncStub)
+
+	// makeFuncImpl contains a stack map for use by the runtime
+	_, _, abid := funcLayout(ftyp, nil)
+
+	impl := &makeFuncImpl{
+		makeFuncCtxt: makeFuncCtxt{
+			fn:      code,
+			stack:   abid.stackPtrs,
+			argLen:  abid.stackCallArgsSize,
+			regPtrs: abid.inRegPtrs,
+		},
+		ftyp: ftyp,
+		fn:   fn,
+	}
+
+	return Value{t, unsafe.Pointer(impl), flag(Func)}
+}
+
+// makeFuncStub is an assembly function that is the code half of
+// the function returned from MakeFunc. It expects a *callReflectFunc
+// as its context register, and its job is to invoke callReflect(ctxt, frame)
+// where ctxt is the context register and frame is a pointer to the first
+// word in the passed-in argument frame.
+func makeFuncStub()
+
+// The first 3 words of this type must be kept in sync with
+// makeFuncImpl and runtime.reflectMethodValue.
+// Any changes should be reflected in all three.
+type methodValue struct {
+	makeFuncCtxt
+	method int
+	rcvr   Value
+}
+*/
+
+// makeMethodValue converts v from the rcvr+method index representation
+// of a method value to an actual method func value, which is
+// basically the receiver value with a special bit set, into a true
+// func value - a value holding an actual func. The output is
+// semantically equivalent to the input as far as the user of package
+// reflect can tell, but the true func representation can be handled
+// by code like Convert and Interface and Assign.
+func makeMethodValue(op string, v Value) Value {
+	/*
+		if v.flag&flagMethod == 0 {
+			panic("reflect: internal error: invalid use of makeMethodValue")
+		}
+
+		// Ignoring the flagMethod bit, v describes the receiver, not the method type.
+		fl := v.flag & (flagRO | flagAddr | flagIndir)
+		fl |= flag(v.typ().Kind())
+		rcvr := Value{v.typ(), v.ptr, fl}
+
+		// v.Type returns the actual type of the method value.
+		ftyp := (*funcType)(unsafe.Pointer(v.Type().(*rtype)))
+
+		code := methodValueCallCodePtr()
+
+		// methodValue contains a stack map for use by the runtime
+		_, _, abid := funcLayout(ftyp, nil)
+		fv := &methodValue{
+			makeFuncCtxt: makeFuncCtxt{
+				fn:      code,
+				stack:   abid.stackPtrs,
+				argLen:  abid.stackCallArgsSize,
+				regPtrs: abid.inRegPtrs,
+			},
+			method: int(v.flag) >> flagMethodShift,
+			rcvr:   rcvr,
+		}
+
+		// Cause panic if method is not appropriate.
+		// The panic would still happen during the call if we omit this,
+		// but we want Interface() and other operations to fail early.
+		methodReceiver(op, fv.rcvr, fv.method)
+
+		return Value{ftyp.Common(), unsafe.Pointer(fv), v.flag&flagRO | flag(Func)}
+	*/
+	panic("todo")
+}
+
+/*
+func methodValueCallCodePtr() uintptr {
+	return abi.FuncPCABI0(methodValueCall)
+}
+
+// methodValueCall is an assembly function that is the code half of
+// the function returned from makeMethodValue. It expects a *methodValue
+// as its context register, and its job is to invoke callMethod(ctxt, frame)
+// where ctxt is the context register and frame is a pointer to the first
+// word in the passed-in argument frame.
+func methodValueCall()
+
+// This structure must be kept in sync with runtime.reflectMethodValue.
+// Any changes should be reflected in all both.
+type makeFuncCtxt struct {
+	fn      uintptr
+	stack   *bitVector // ptrmap for both stack args and results
+	argLen  uintptr    // just args
+	regPtrs abi.IntArgRegBitmap
+}
+
+// moveMakeFuncArgPtrs uses ctxt.regPtrs to copy integer pointer arguments
+// in args.Ints to args.Ptrs where the GC can see them.
+//
+// This is similar to what reflectcallmove does in the runtime, except
+// that happens on the return path, whereas this happens on the call path.
+//
+// nosplit because pointers are being held in uintptr slots in args, so
+// having our stack scanned now could lead to accidentally freeing
+// memory.
+//
+//go:nosplit
+func moveMakeFuncArgPtrs(ctxt *makeFuncCtxt, args *abi.RegArgs) {
+	for i, arg := range args.Ints {
+		// Avoid write barriers! Because our write barrier enqueues what
+		// was there before, we might enqueue garbage.
+		if ctxt.regPtrs.Get(i) {
+			*(*uintptr)(unsafe.Pointer(&args.Ptrs[i])) = arg
+		} else {
+			// We *must* zero this space ourselves because it's defined in
+			// assembly code and the GC will scan these pointers. Otherwise,
+			// there will be garbage here.
+			*(*uintptr)(unsafe.Pointer(&args.Ptrs[i])) = 0
+		}
+	}
+}
+*/

internal/lib/reflect/type.go

@@ -726,6 +726,17 @@ func (t *rtype) IsVariadic() bool {
 	panic("todo")
 }
 
+// add returns p+x.
+//
+// The whySafe string is ignored, so that the function still inlines
+// as efficiently as p+x, but all call sites should use the string to
+// record why the addition is safe, which is to say why the addition
+// does not cause x to advance to the very end of p's allocation
+// and therefore point incorrectly at the next block in memory.
+func add(p unsafe.Pointer, x uintptr, whySafe string) unsafe.Pointer {
+	return unsafe.Pointer(uintptr(p) + x)
+}
+
 // A StructField describes a single field in a struct.
 type StructField struct {
 	// Name is the field name.
@@ -837,13 +848,13 @@ func TypeOf(i any) Type {
 	return toType((*abi.Type)(unsafe.Pointer(eface.typ)))
 }
 
-/* TODO(xsw):
 // rtypeOf directly extracts the *rtype of the provided value.
 func rtypeOf(i any) *abi.Type {
 	eface := *(*emptyInterface)(unsafe.Pointer(&i))
 	return eface.typ
 }
 
+/* TODO(xsw):
 // ptrMap is the cache for PointerTo.
 var ptrMap sync.Map // map[*rtype]*ptrType
 */
@@ -959,6 +970,241 @@ func (t *rtype) Comparable() bool {
 	return t.t.Equal != nil
 }
 
+// implements reports whether the type V implements the interface type T.
+func implements(T, V *abi.Type) bool {
+	if T.Kind() != abi.Interface {
+		return false
+	}
+	t := (*interfaceType)(unsafe.Pointer(T))
+	if len(t.Methods) == 0 {
+		return true
+	}
+
+	/*
+		// The same algorithm applies in both cases, but the
+		// method tables for an interface type and a concrete type
+		// are different, so the code is duplicated.
+		// In both cases the algorithm is a linear scan over the two
+		// lists - T's methods and V's methods - simultaneously.
+		// Since method tables are stored in a unique sorted order
+		// (alphabetical, with no duplicate method names), the scan
+		// through V's methods must hit a match for each of T's
+		// methods along the way, or else V does not implement T.
+		// This lets us run the scan in overall linear time instead of
+		// the quadratic time  a naive search would require.
+		// See also ../runtime/iface.go.
+		if V.Kind() == abi.Interface {
+			v := (*interfaceType)(unsafe.Pointer(V))
+			i := 0
+			for j := 0; j < len(v.Methods); j++ {
+				tm := &t.Methods[i]
+				tmName := t.nameOff(tm.Name)
+				vm := &v.Methods[j]
+				vmName := nameOffFor(V, vm.Name)
+				if vmName.Name() == tmName.Name() && typeOffFor(V, vm.Typ) == t.typeOff(tm.Typ) {
+					if !tmName.IsExported() {
+						tmPkgPath := pkgPath(tmName)
+						if tmPkgPath == "" {
+							tmPkgPath = t.PkgPath.Name()
+						}
+						vmPkgPath := pkgPath(vmName)
+						if vmPkgPath == "" {
+							vmPkgPath = v.PkgPath.Name()
+						}
+						if tmPkgPath != vmPkgPath {
+							continue
+						}
+					}
+					if i++; i >= len(t.Methods) {
+						return true
+					}
+				}
+			}
+			return false
+		}
+
+		v := V.Uncommon()
+		if v == nil {
+			return false
+		}
+		i := 0
+		vmethods := v.Methods()
+		for j := 0; j < int(v.Mcount); j++ {
+			tm := &t.Methods[i]
+			tmName := t.nameOff(tm.Name)
+			vm := vmethods[j]
+			vmName := nameOffFor(V, vm.Name)
+			if vmName.Name() == tmName.Name() && typeOffFor(V, vm.Mtyp) == t.typeOff(tm.Typ) {
+				if !tmName.IsExported() {
+					tmPkgPath := pkgPath(tmName)
+					if tmPkgPath == "" {
+						tmPkgPath = t.PkgPath.Name()
+					}
+					vmPkgPath := pkgPath(vmName)
+					if vmPkgPath == "" {
+						vmPkgPath = nameOffFor(V, v.PkgPath).Name()
+					}
+					if tmPkgPath != vmPkgPath {
+						continue
+					}
+				}
+				if i++; i >= len(t.Methods) {
+					return true
+				}
+			}
+		}
+		return false
+	*/
+	panic("todo")
+}
+
+// specialChannelAssignability reports whether a value x of channel type V
+// can be directly assigned (using memmove) to another channel type T.
+// https://golang.org/doc/go_spec.html#Assignability
+// T and V must be both of Chan kind.
+func specialChannelAssignability(T, V *abi.Type) bool {
+	/*
+		// Special case:
+		// x is a bidirectional channel value, T is a channel type,
+		// x's type V and T have identical element types,
+		// and at least one of V or T is not a defined type.
+		return V.ChanDir() == abi.BothDir && (nameFor(T) == "" || nameFor(V) == "") && haveIdenticalType(T.Elem(), V.Elem(), true)
+	*/
+	panic("todo")
+}
+
+// directlyAssignable reports whether a value x of type V can be directly
+// assigned (using memmove) to a value of type T.
+// https://golang.org/doc/go_spec.html#Assignability
+// Ignoring the interface rules (implemented elsewhere)
+// and the ideal constant rules (no ideal constants at run time).
+func directlyAssignable(T, V *abi.Type) bool {
+	// x's type V is identical to T?
+	if T == V {
+		return true
+	}
+
+	// Otherwise at least one of T and V must not be defined
+	// and they must have the same kind.
+	if T.HasName() && V.HasName() || T.Kind() != V.Kind() {
+		return false
+	}
+
+	if T.Kind() == abi.Chan && specialChannelAssignability(T, V) {
+		return true
+	}
+
+	// x's type T and V must have identical underlying types.
+	return haveIdenticalUnderlyingType(T, V, true)
+}
+
+func haveIdenticalType(T, V *abi.Type, cmpTags bool) bool {
+	if cmpTags {
+		return T == V
+	}
+
+	if nameFor(T) != nameFor(V) || T.Kind() != V.Kind() || pkgPathFor(T) != pkgPathFor(V) {
+		return false
+	}
+
+	return haveIdenticalUnderlyingType(T, V, false)
+}
+
+func haveIdenticalUnderlyingType(T, V *abi.Type, cmpTags bool) bool {
+	if T == V {
+		return true
+	}
+
+	kind := Kind(T.Kind())
+	if kind != Kind(V.Kind()) {
+		return false
+	}
+
+	// Non-composite types of equal kind have same underlying type
+	// (the predefined instance of the type).
+	if Bool <= kind && kind <= Complex128 || kind == String || kind == UnsafePointer {
+		return true
+	}
+
+	/*
+		// Composite types.
+		switch kind {
+		case Array:
+			return T.Len() == V.Len() && haveIdenticalType(T.Elem(), V.Elem(), cmpTags)
+
+		case Chan:
+			return V.ChanDir() == T.ChanDir() && haveIdenticalType(T.Elem(), V.Elem(), cmpTags)
+
+		case Func:
+			t := (*funcType)(unsafe.Pointer(T))
+			v := (*funcType)(unsafe.Pointer(V))
+			if t.OutCount != v.OutCount || t.InCount != v.InCount {
+				return false
+			}
+			for i := 0; i < t.NumIn(); i++ {
+				if !haveIdenticalType(t.In(i), v.In(i), cmpTags) {
+					return false
+				}
+			}
+			for i := 0; i < t.NumOut(); i++ {
+				if !haveIdenticalType(t.Out(i), v.Out(i), cmpTags) {
+					return false
+				}
+			}
+			return true
+
+		case Interface:
+			t := (*interfaceType)(unsafe.Pointer(T))
+			v := (*interfaceType)(unsafe.Pointer(V))
+			if len(t.Methods) == 0 && len(v.Methods) == 0 {
+				return true
+			}
+			// Might have the same methods but still
+			// need a run time conversion.
+			return false
+
+		case Map:
+			return haveIdenticalType(T.Key(), V.Key(), cmpTags) && haveIdenticalType(T.Elem(), V.Elem(), cmpTags)
+
+		case Pointer, Slice:
+			return haveIdenticalType(T.Elem(), V.Elem(), cmpTags)
+
+		case Struct:
+			t := (*structType)(unsafe.Pointer(T))
+			v := (*structType)(unsafe.Pointer(V))
+			if len(t.Fields) != len(v.Fields) {
+				return false
+			}
+			if t.PkgPath.Name() != v.PkgPath.Name() {
+				return false
+			}
+			for i := range t.Fields {
+				tf := &t.Fields[i]
+				vf := &v.Fields[i]
+				if tf.Name.Name() != vf.Name.Name() {
+					return false
+				}
+				if !haveIdenticalType(tf.Typ, vf.Typ, cmpTags) {
+					return false
+				}
+				if cmpTags && tf.Name.Tag() != vf.Name.Tag() {
+					return false
+				}
+				if tf.Offset != vf.Offset {
+					return false
+				}
+				if tf.Embedded() != vf.Embedded() {
+					return false
+				}
+			}
+			return true
+		}
+
+		return false
+	*/
+	panic("todo")
+}
+
 // SliceOf returns the slice type with element type t.
 // For example, if t represents int, SliceOf(t) represents []int.
 func SliceOf(t Type) Type {

internal/lib/reflect/unsafeheader.go

@@ -2,11 +2,6 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// Package unsafeheader contains header declarations for the Go runtime's slice
-// and string implementations.
-//
-// This package allows packages that cannot import "reflect" to use types that
-// are tested to be equivalent to reflect.SliceHeader and reflect.StringHeader.
 package reflect
 
 import (

internal/lib/reflect/value.go

@@ -193,6 +193,28 @@ func (e *ValueError) Error() string {
 	return "reflect: call of " + e.Method + " on " + e.Kind.String() + " Value"
 }
 
+// valueMethodName returns the name of the exported calling method on Value.
+func valueMethodName() string {
+	/* TODO(xsw):
+	var pc [5]uintptr
+	n := runtime.Callers(1, pc[:])
+	frames := runtime.CallersFrames(pc[:n])
+	var frame runtime.Frame
+	for more := true; more; {
+		const prefix = "reflect.Value."
+		frame, more = frames.Next()
+		name := frame.Function
+		if len(name) > len(prefix) && name[:len(prefix)] == prefix {
+			methodName := name[len(prefix):]
+			if len(methodName) > 0 && 'A' <= methodName[0] && methodName[0] <= 'Z' {
+				return name
+			}
+		}
+	}
+	*/
+	return "unknown method"
+}
+
 // emptyInterface is the header for an interface{} value.
 type emptyInterface struct {
 	typ  *abi.Type
@@ -212,6 +234,125 @@ type nonEmptyInterface struct {
 	word unsafe.Pointer
 }
 
+// mustBe panics if f's kind is not expected.
+// Making this a method on flag instead of on Value
+// (and embedding flag in Value) means that we can write
+// the very clear v.mustBe(Bool) and have it compile into
+// v.flag.mustBe(Bool), which will only bother to copy the
+// single important word for the receiver.
+func (f flag) mustBe(expected Kind) {
+	// TODO(mvdan): use f.kind() again once mid-stack inlining gets better
+	if Kind(f&flagKindMask) != expected {
+		panic(&ValueError{valueMethodName(), f.kind()})
+	}
+}
+
+// mustBeExported panics if f records that the value was obtained using
+// an unexported field.
+func (f flag) mustBeExported() {
+	if f == 0 || f&flagRO != 0 {
+		f.mustBeExportedSlow()
+	}
+}
+
+func (f flag) mustBeExportedSlow() {
+	if f == 0 {
+		panic(&ValueError{valueMethodName(), Invalid})
+	}
+	if f&flagRO != 0 {
+		panic("reflect: " + valueMethodName() + " using value obtained using unexported field")
+	}
+}
+
+// mustBeAssignable panics if f records that the value is not assignable,
+// which is to say that either it was obtained using an unexported field
+// or it is not addressable.
+func (f flag) mustBeAssignable() {
+	if f&flagRO != 0 || f&flagAddr == 0 {
+		f.mustBeAssignableSlow()
+	}
+}
+
+func (f flag) mustBeAssignableSlow() {
+	if f == 0 {
+		panic(&ValueError{valueMethodName(), Invalid})
+	}
+	// Assignable if addressable and not read-only.
+	if f&flagRO != 0 {
+		panic("reflect: " + valueMethodName() + " using value obtained using unexported field")
+	}
+	if f&flagAddr == 0 {
+		panic("reflect: " + valueMethodName() + " using unaddressable value")
+	}
+}
+
+// Addr returns a pointer value representing the address of v.
+// It panics if CanAddr() returns false.
+// Addr is typically used to obtain a pointer to a struct field
+// or slice element in order to call a method that requires a
+// pointer receiver.
+func (v Value) Addr() Value {
+	if v.flag&flagAddr == 0 {
+		panic("reflect.Value.Addr of unaddressable value")
+	}
+	// Preserve flagRO instead of using v.flag.ro() so that
+	// v.Addr().Elem() is equivalent to v (#32772)
+	fl := v.flag & flagRO
+	return Value{ptrTo(v.typ()), v.ptr, fl | flag(Pointer)}
+}
+
+// Bool returns v's underlying value.
+// It panics if v's kind is not Bool.
+func (v Value) Bool() bool {
+	// panicNotBool is split out to keep Bool inlineable.
+	if v.kind() != Bool {
+		v.panicNotBool()
+	}
+	return *(*bool)(v.ptr)
+}
+
+func (v Value) panicNotBool() {
+	v.mustBe(Bool)
+}
+
+var bytesType = rtypeOf(([]byte)(nil))
+
+// Bytes returns v's underlying value.
+// It panics if v's underlying value is not a slice of bytes or
+// an addressable array of bytes.
+func (v Value) Bytes() []byte {
+	// bytesSlow is split out to keep Bytes inlineable for unnamed []byte.
+	if v.typ_ == bytesType { // ok to use v.typ_ directly as comparison doesn't cause escape
+		return *(*[]byte)(v.ptr)
+	}
+	return v.bytesSlow()
+}
+
+func (v Value) bytesSlow() []byte {
+	/*
+		switch v.kind() {
+		case Slice:
+			if v.typ().Elem().Kind() != abi.Uint8 {
+				panic("reflect.Value.Bytes of non-byte slice")
+			}
+			// Slice is always bigger than a word; assume flagIndir.
+			return *(*[]byte)(v.ptr)
+		case Array:
+			if v.typ().Elem().Kind() != abi.Uint8 {
+				panic("reflect.Value.Bytes of non-byte array")
+			}
+			if !v.CanAddr() {
+				panic("reflect.Value.Bytes of unaddressable byte array")
+			}
+			p := (*byte)(v.ptr)
+			n := int((*arrayType)(unsafe.Pointer(v.typ())).Len)
+			return unsafe.Slice(p, n)
+		}
+		panic(&ValueError{"reflect.Value.Bytes", v.kind()})
+	*/
+	panic("todo")
+}
+
 // CanFloat reports whether Float can be used without panicking.
 func (v Value) CanFloat() bool {
 	switch v.kind() {
@@ -235,14 +376,34 @@ func (v Value) Float() float64 {
 	panic(&ValueError{"reflect.Value.Float", v.kind()})
 }
 
-// TODO(xsw):
+var uint8Type = rtypeOf(uint8(0))
-// var uint8Type = rtypeOf(uint8(0))
 
 // Index returns v's i'th element.
 // It panics if v's Kind is not Array, Slice, or String or i is out of range.
 func (v Value) Index(i int) Value {
-	/*
 	switch v.kind() {
+	case Slice:
+		// Element flag same as Elem of Pointer.
+		// Addressable, indirect, possibly read-only.
+		s := (*unsafeheaderSlice)(v.ptr)
+		if uint(i) >= uint(s.Len) {
+			panic("reflect: slice index out of range")
+		}
+		tt := (*sliceType)(unsafe.Pointer(v.typ()))
+		typ := tt.Elem
+		val := arrayAt(s.Data, i, typ.Size(), "i < s.Len")
+		fl := flagAddr | flagIndir | v.flag.ro() | flag(typ.Kind())
+		return Value{typ, val, fl}
+
+	case String:
+		s := (*unsafeheaderString)(v.ptr)
+		if uint(i) >= uint(s.Len) {
+			panic("reflect: string index out of range")
+		}
+		p := arrayAt(s.Data, i, 1, "i < s.Len")
+		fl := v.flag.ro() | flag(Uint8) | flagIndir
+		return Value{uint8Type, p, fl}
+
 	case Array:
 		tt := (*arrayType)(unsafe.Pointer(v.typ()))
 		if uint(i) >= uint(tt.Len) {
@@ -259,32 +420,8 @@ func (v Value) Index(i int) Value {
 		val := add(v.ptr, offset, "same as &v[i], i < tt.len")
 		fl := v.flag&(flagIndir|flagAddr) | v.flag.ro() | flag(typ.Kind()) // bits same as overall array
 		return Value{typ, val, fl}
-
-		case Slice:
-			// Element flag same as Elem of Pointer.
-			// Addressable, indirect, possibly read-only.
-			s := (*unsafeheader.Slice)(v.ptr)
-			if uint(i) >= uint(s.Len) {
-				panic("reflect: slice index out of range")
-			}
-			tt := (*sliceType)(unsafe.Pointer(v.typ()))
-			typ := tt.Elem
-			val := arrayAt(s.Data, i, typ.Size(), "i < s.Len")
-			fl := flagAddr | flagIndir | v.flag.ro() | flag(typ.Kind())
-			return Value{typ, val, fl}
-
-		case String:
-			s := (*unsafeheader.String)(v.ptr)
-			if uint(i) >= uint(s.Len) {
-				panic("reflect: string index out of range")
-			}
-			p := arrayAt(s.Data, i, 1, "i < s.Len")
-			fl := v.flag.ro() | flag(Uint8) | flagIndir
-			return Value{uint8Type, p, fl}
 	}
 	panic(&ValueError{"reflect.Value.Index", v.kind()})
-	*/
-	panic("todo")
 }
 
 // CanInt reports whether Int can be used without panicking.
@@ -300,23 +437,34 @@ func (v Value) CanInt() bool {
 // Int returns v's underlying value, as an int64.
 // It panics if v's Kind is not Int, Int8, Int16, Int32, or Int64.
 func (v Value) Int() int64 {
-	k := v.kind()
+	f := v.flag
+	k := f.kind()
 	p := v.ptr
+	if f&flagAddr != 0 {
 		switch k {
 		case Int:
-		return int64(uintptr(p))
+			return int64(*(*int)(p))
 		case Int8:
-		return int64(uintptr(p))
+			return int64(*(*int8)(p))
 		case Int16:
-		return int64(uintptr(p))
+			return int64(*(*int16)(p))
 		case Int32:
-		return int64(uintptr(p))
+			return int64(*(*int32)(p))
 		case Int64:
-		if unsafe.Sizeof(uintptr(0)) == 8 {
+			return *(*int64)(p)
+		}
+	} else if unsafe.Sizeof(uintptr(0)) == 8 {
+		if k >= Int && k <= Int64 {
 			return int64(uintptr(p))
 		}
+	} else {
+		if k >= Int && k <= Int32 {
+			return int64(uintptr(p))
+		}
+		if k == Int64 {
 			return *(*int64)(p)
 		}
+	}
 	panic(&ValueError{"reflect.Value.Int", v.kind()})
 }
 
@@ -594,6 +742,107 @@ func (v Value) lenNonSlice() int {
 	panic("todo")
 }
 
+// Set assigns x to the value v.
+// It panics if CanSet returns false.
+// As in Go, x's value must be assignable to v's type and
+// must not be derived from an unexported field.
+func (v Value) Set(x Value) {
+	v.mustBeAssignable()
+	x.mustBeExported() // do not let unexported x leak
+	var target unsafe.Pointer
+	if v.kind() == Interface {
+		target = v.ptr
+	}
+	x = x.assignTo("reflect.Set", v.typ(), target)
+	if x.flag&flagIndir != 0 {
+		if x.ptr == unsafe.Pointer(&runtime.ZeroVal[0]) {
+			typedmemclr(v.typ(), v.ptr)
+		} else {
+			typedmemmove(v.typ(), v.ptr, x.ptr)
+		}
+	} else {
+		*(*unsafe.Pointer)(v.ptr) = x.ptr
+	}
+}
+
+// SetBool sets v's underlying value.
+// It panics if v's Kind is not Bool or if CanSet() is false.
+func (v Value) SetBool(x bool) {
+	v.mustBeAssignable()
+	v.mustBe(Bool)
+	*(*bool)(v.ptr) = x
+}
+
+// SetBytes sets v's underlying value.
+// It panics if v's underlying value is not a slice of bytes.
+func (v Value) SetBytes(x []byte) {
+	v.mustBeAssignable()
+	v.mustBe(Slice)
+	if toRType(v.typ()).Elem().Kind() != Uint8 { // TODO add Elem method, fix mustBe(Slice) to return slice.
+		panic("reflect.Value.SetBytes of non-byte slice")
+	}
+	*(*[]byte)(v.ptr) = x
+}
+
+// setRunes sets v's underlying value.
+// It panics if v's underlying value is not a slice of runes (int32s).
+func (v Value) setRunes(x []rune) {
+	v.mustBeAssignable()
+	v.mustBe(Slice)
+	if v.typ().Elem().Kind() != abi.Int32 {
+		panic("reflect.Value.setRunes of non-rune slice")
+	}
+	*(*[]rune)(v.ptr) = x
+}
+
+// SetComplex sets v's underlying value to x.
+// It panics if v's Kind is not Complex64 or Complex128, or if CanSet() is false.
+func (v Value) SetComplex(x complex128) {
+	v.mustBeAssignable()
+	switch k := v.kind(); k {
+	default:
+		panic(&ValueError{"reflect.Value.SetComplex", v.kind()})
+	case Complex64:
+		*(*complex64)(v.ptr) = complex64(x)
+	case Complex128:
+		*(*complex128)(v.ptr) = x
+	}
+}
+
+// SetFloat sets v's underlying value to x.
+// It panics if v's Kind is not Float32 or Float64, or if CanSet() is false.
+func (v Value) SetFloat(x float64) {
+	v.mustBeAssignable()
+	switch k := v.kind(); k {
+	default:
+		panic(&ValueError{"reflect.Value.SetFloat", v.kind()})
+	case Float32:
+		*(*float32)(v.ptr) = float32(x)
+	case Float64:
+		*(*float64)(v.ptr) = x
+	}
+}
+
+// SetInt sets v's underlying value to x.
+// It panics if v's Kind is not Int, Int8, Int16, Int32, or Int64, or if CanSet() is false.
+func (v Value) SetInt(x int64) {
+	v.mustBeAssignable()
+	switch k := v.kind(); k {
+	default:
+		panic(&ValueError{"reflect.Value.SetInt", v.kind()})
+	case Int:
+		*(*int)(v.ptr) = int(x)
+	case Int8:
+		*(*int8)(v.ptr) = int8(x)
+	case Int16:
+		*(*int16)(v.ptr) = int16(x)
+	case Int32:
+		*(*int32)(v.ptr) = int32(x)
+	case Int64:
+		*(*int64)(v.ptr) = x
+	}
+}
+
 //go:linkname unsafe_New github.com/goplus/llgo/internal/runtime.New
 func unsafe_New(*abi.Type) unsafe.Pointer
 
@@ -610,6 +859,94 @@ func ValueOf(i any) Value {
 	return unpackEface(i)
 }
 
+// arrayAt returns the i-th element of p,
+// an array whose elements are eltSize bytes wide.
+// The array pointed at by p must have at least i+1 elements:
+// it is invalid (but impossible to check here) to pass i >= len,
+// because then the result will point outside the array.
+// whySafe must explain why i < len. (Passing "i < len" is fine;
+// the benefit is to surface this assumption at the call site.)
+func arrayAt(p unsafe.Pointer, i int, eltSize uintptr, whySafe string) unsafe.Pointer {
+	return add(p, uintptr(i)*eltSize, "i < len")
+}
+
+// Grow increases the slice's capacity, if necessary, to guarantee space for
+// another n elements. After Grow(n), at least n elements can be appended
+// to the slice without another allocation.
+//
+// It panics if v's Kind is not a Slice or if n is negative or too large to
+// allocate the memory.
+func (v Value) Grow(n int) {
+	v.mustBeAssignable()
+	v.mustBe(Slice)
+	v.grow(n)
+}
+
+// grow is identical to Grow but does not check for assignability.
+func (v Value) grow(n int) {
+	p := (*unsafeheaderSlice)(v.ptr)
+	oldLen := p.Len
+	switch {
+	case n < 0:
+		panic("reflect.Value.Grow: negative len")
+	case oldLen+n < 0:
+		panic("reflect.Value.Grow: slice overflow")
+	case oldLen+n > p.Cap:
+		t := v.typ().Elem()
+		*p = growslice(*p, n, int(t.Size_))
+		p.Len = oldLen // set oldLen back
+	}
+}
+
+// extendSlice extends a slice by n elements.
+//
+// Unlike Value.grow, which modifies the slice in place and
+// does not change the length of the slice in place,
+// extendSlice returns a new slice value with the length
+// incremented by the number of specified elements.
+func (v Value) extendSlice(n int) Value {
+	v.mustBeExported()
+	v.mustBe(Slice)
+
+	// Shallow copy the slice header to avoid mutating the source slice.
+	sh := *(*unsafeheaderSlice)(v.ptr)
+	s := &sh
+	v.ptr = unsafe.Pointer(s)
+	v.flag = flagIndir | flag(Slice) // equivalent flag to MakeSlice
+
+	v.grow(n) // fine to treat as assignable since we allocate a new slice header
+	s.Len += n
+	return v
+}
+
+// Append appends the values x to a slice s and returns the resulting slice.
+// As in Go, each x's value must be assignable to the slice's element type.
+func Append(s Value, x ...Value) Value {
+	s.mustBe(Slice)
+	n := s.Len()
+	s = s.extendSlice(len(x))
+	for i, v := range x {
+		s.Index(n + i).Set(v)
+	}
+	return s
+}
+
+// AppendSlice appends a slice t to a slice s and returns the resulting slice.
+// The slices s and t must have the same element type.
+func AppendSlice(s, t Value) Value {
+	/*
+		s.mustBe(Slice)
+		t.mustBe(Slice)
+		typesMustMatch("reflect.AppendSlice", s.Type().Elem(), t.Type().Elem())
+		ns := s.Len()
+		nt := t.Len()
+		s = s.extendSlice(nt)
+		Copy(s.Slice(ns, ns+nt), t)
+		return s
+	*/
+	panic("todo")
+}
+
 // Zero returns a Value representing the zero value for the specified type.
 // The result is different from the zero value of the Value struct,
 // which represents no value at all.
@@ -637,6 +974,79 @@ func Zero(typ Type) Value {
 // must match declarations in runtime/map.go.
 const maxZero = runtime.MaxZero
 
+// New returns a Value representing a pointer to a new zero value
+// for the specified type. That is, the returned Value's Type is PointerTo(typ).
+func New(typ Type) Value {
+	/*
+		if typ == nil {
+			panic("reflect: New(nil)")
+		}
+		t := &typ.(*rtype).t
+		pt := ptrTo(t)
+		if ifaceIndir(pt) {
+			// This is a pointer to a not-in-heap type.
+			panic("reflect: New of type that may not be allocated in heap (possibly undefined cgo C type)")
+		}
+		ptr := unsafe_New(t)
+		fl := flag(Pointer)
+		return Value{pt, ptr, fl}
+	*/
+	panic("todo")
+}
+
+// NewAt returns a Value representing a pointer to a value of the
+// specified type, using p as that pointer.
+func NewAt(typ Type, p unsafe.Pointer) Value {
+	fl := flag(Pointer)
+	t := typ.(*rtype)
+	return Value{t.ptrTo(), p, fl}
+}
+
+// assignTo returns a value v that can be assigned directly to dst.
+// It panics if v is not assignable to dst.
+// For a conversion to an interface type, target, if not nil,
+// is a suggested scratch space to use.
+// target must be initialized memory (or nil).
+func (v Value) assignTo(context string, dst *abi.Type, target unsafe.Pointer) Value {
+	if v.flag&flagMethod != 0 {
+		v = makeMethodValue(context, v)
+	}
+
+	switch {
+	case directlyAssignable(dst, v.typ()):
+		// Overwrite type so that they match.
+		// Same memory layout, so no harm done.
+		fl := v.flag&(flagAddr|flagIndir) | v.flag.ro()
+		fl |= flag(dst.Kind())
+		return Value{dst, v.ptr, fl}
+
+	case implements(dst, v.typ()):
+		if v.Kind() == Interface && v.IsNil() {
+			// A nil ReadWriter passed to nil Reader is OK,
+			// but using ifaceE2I below will panic.
+			// Avoid the panic by returning a nil dst (e.g., Reader) explicitly.
+			return Value{dst, nil, flag(Interface)}
+		}
+		/* TODO(xsw):
+		x := valueInterface(v, false)
+		if target == nil {
+			target = unsafe_New(dst)
+		}
+		if dst.NumMethod() == 0 {
+			*(*any)(target) = x
+		} else {
+			ifaceE2I(dst, x, target)
+		}
+		return Value{dst, target, flagIndir | flag(Interface)}
+		*/
+	}
+
+	// Failed.
+	// TODO(xsw):
+	// panic(context + ": value of type " + stringFor(v.typ()) + " is not assignable to type " + stringFor(dst))
+	panic("todo")
+}
+
 // memmove copies size bytes to dst from src. No write barriers are used.
 //
 //go:linkname memmove C.memmove
@@ -647,12 +1057,12 @@ func memmove(dst, src unsafe.Pointer, size uintptr)
 //go:linkname typedmemmove github.com/goplus/llgo/internal/runtime.Typedmemmove
 func typedmemmove(t *abi.Type, dst, src unsafe.Pointer)
 
-/* TODO(xsw):
 // typedmemclr zeros the value at ptr of type t.
 //
-//go:noescape
+//go:linkname typedmemclr github.com/goplus/llgo/internal/runtime.Typedmemclr
 func typedmemclr(t *abi.Type, ptr unsafe.Pointer)
 
+/* TODO(xsw):
 // typedmemclrpartial is like typedmemclr but assumes that
 // dst points off bytes into the value and only clears size bytes.
 //
@@ -675,7 +1085,7 @@ func typedarrayclear(elemType *abi.Type, ptr unsafe.Pointer, len int)
 func typehash(t *abi.Type, p unsafe.Pointer, h uintptr) uintptr
 
 func verifyNotInHeapPtr(p uintptr) bool
-
-//go:noescape
-func growslice(t *abi.Type, old unsafeheaderSlice, num int) unsafeheaderSlice
 */
+
+//go:linkname growslice github.com/goplus/llgo/internal/runtime.GrowSlice
+func growslice(src unsafeheaderSlice, num, etSize int) unsafeheaderSlice

internal/runtime/mbarrier.go

@@ -286,6 +286,7 @@ func reflect_typedslicecopy(elemType *_type, dst, src slice) int {
 	}
 	return typedslicecopy(elemType, dst.array, dst.len, src.array, src.len)
 }
+*/
 
 // typedmemclr clears the typed memory at ptr with type typ. The
 // memory at ptr must already be initialized (and hence in type-safe
@@ -296,20 +297,11 @@ func reflect_typedslicecopy(elemType *_type, dst, src slice) int {
 // call memclrHasPointers.
 //
 // TODO: A "go:nosplitrec" annotation would be perfect for this.
-//
+func Typedmemclr(typ *Type, ptr unsafe.Pointer) {
-//go:nosplit
+	c.Memset(ptr, 0, typ.Size_)
-func typedmemclr(typ *_type, ptr unsafe.Pointer) {
-	if writeBarrier.needed && typ.PtrBytes != 0 {
-		bulkBarrierPreWrite(uintptr(ptr), 0, typ.PtrBytes)
-	}
-	memclrNoHeapPointers(ptr, typ.Size_)
-}
-
-//go:linkname reflect_typedmemclr reflect.typedmemclr
-func reflect_typedmemclr(typ *_type, ptr unsafe.Pointer) {
-	typedmemclr(typ, ptr)
 }
 
+/*
 //go:linkname reflect_typedmemclrpartial reflect.typedmemclrpartial
 func reflect_typedmemclrpartial(typ *_type, ptr unsafe.Pointer, off, size uintptr) {
 	if writeBarrier.needed && typ.PtrBytes != 0 {

internal/runtime/slice.go

@@ -1,40 +0,0 @@
-// Copyright 2009 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package runtime
-
-// nextslicecap computes the next appropriate slice length.
-func nextslicecap(newLen, oldCap int) int {
-	newcap := oldCap
-	doublecap := newcap + newcap
-	if newLen > doublecap {
-		return newLen
-	}
-
-	const threshold = 256
-	if oldCap < threshold {
-		return doublecap
-	}
-	for {
-		// Transition from growing 2x for small slices
-		// to growing 1.25x for large slices. This formula
-		// gives a smooth-ish transition between the two.
-		newcap += (newcap + 3*threshold) >> 2
-
-		// We need to check `newcap >= newLen` and whether `newcap` overflowed.
-		// newLen is guaranteed to be larger than zero, hence
-		// when newcap overflows then `uint(newcap) > uint(newLen)`.
-		// This allows to check for both with the same comparison.
-		if uint(newcap) >= uint(newLen) {
-			break
-		}
-	}
-
-	// Set newcap to the requested cap when
-	// the newcap calculation overflowed.
-	if newcap <= 0 {
-		return newLen
-	}
-	return newcap
-}

internal/runtime/z_slice.go

@@ -51,7 +51,15 @@ func SliceAppend(src Slice, data unsafe.Pointer, num, etSize int) Slice {
 		return src
 	}
 	oldLen := src.len
-	newLen := src.len + num
+	src = GrowSlice(src, num, etSize)
+	c.Memcpy(c.Advance(src.data, oldLen*etSize), data, uintptr(num*etSize))
+	return src
+}
+
+// GrowSlice grows slice and returns the grown slice.
+func GrowSlice(src Slice, num, etSize int) Slice {
+	oldLen := src.len
+	newLen := oldLen + num
 	if newLen > src.cap {
 		newCap := nextslicecap(newLen, src.cap)
 		p := AllocZ(uintptr(newCap * etSize))
@@ -62,10 +70,44 @@ func SliceAppend(src Slice, data unsafe.Pointer, num, etSize int) Slice {
 		src.cap = newCap
 	}
 	src.len = newLen
-	c.Memcpy(c.Advance(src.data, oldLen*etSize), data, uintptr(num*etSize))
 	return src
 }
 
+// nextslicecap computes the next appropriate slice length.
+func nextslicecap(newLen, oldCap int) int {
+	newcap := oldCap
+	doublecap := newcap + newcap
+	if newLen > doublecap {
+		return newLen
+	}
+
+	const threshold = 256
+	if oldCap < threshold {
+		return doublecap
+	}
+	for {
+		// Transition from growing 2x for small slices
+		// to growing 1.25x for large slices. This formula
+		// gives a smooth-ish transition between the two.
+		newcap += (newcap + 3*threshold) >> 2
+
+		// We need to check `newcap >= newLen` and whether `newcap` overflowed.
+		// newLen is guaranteed to be larger than zero, hence
+		// when newcap overflows then `uint(newcap) > uint(newLen)`.
+		// This allows to check for both with the same comparison.
+		if uint(newcap) >= uint(newLen) {
+			break
+		}
+	}
+
+	// Set newcap to the requested cap when
+	// the newcap calculation overflowed.
+	if newcap <= 0 {
+		return newLen
+	}
+	return newcap
+}
+
 // SliceCopy copy data to slice and returns a slice.
 func SliceCopy(dst Slice, data unsafe.Pointer, num int, etSize int) int {
 	n := dst.len