Files
moxa/interp/value.go
Marc Vertes 7d8fdbc1fc interp: fix closure in a struct field
Functions in a struct fields are always wrapped (as potentially
used by the runtime), so generate a function wrapper also for
closure when assigned to a struct field.

When such a function is called from the interpreter, ensure that
interface arguments are also wrapped so method and receiver resolution
can be performed.

Fixes partially #1043.
2021-03-11 15:26:04 +01:00

602 lines
16 KiB
Go

package interp
import (
"go/constant"
"reflect"
)
const (
notInFrame = -1 // value of node.findex for literal values (not in frame)
globalFrame = -1 // value of node.level for global symbols
)
func valueGenerator(n *node, i int) func(*frame) reflect.Value {
switch n.level {
case globalFrame:
return func(f *frame) reflect.Value { return valueOf(f.root.data, i) }
case 0:
return func(f *frame) reflect.Value { return valueOf(f.data, i) }
case 1:
return func(f *frame) reflect.Value { return valueOf(f.anc.data, i) }
case 2:
return func(f *frame) reflect.Value { return valueOf(f.anc.anc.data, i) }
default:
return func(f *frame) reflect.Value {
for level := n.level; level > 0; level-- {
f = f.anc
}
return valueOf(f.data, i)
}
}
}
// valueOf safely recovers the ith element of data. This is necessary
// because a cancellation prior to any evaluation result may leave
// the frame's data empty.
func valueOf(data []reflect.Value, i int) reflect.Value {
if i < len(data) {
return data[i]
}
return reflect.Value{}
}
func genValueBinMethodOnInterface(n *node, defaultGen func(*frame) reflect.Value) func(*frame) reflect.Value {
if n == nil || n.child == nil || n.child[0] == nil ||
n.child[0].child == nil || n.child[0].child[0] == nil {
return defaultGen
}
c0 := n.child[0]
if c0.child[1] == nil || c0.child[1].ident == "" {
return defaultGen
}
value0 := genValue(c0.child[0])
return func(f *frame) reflect.Value {
v := value0(f)
var nod *node
for v.IsValid() {
// Traverse interface indirections to find out concrete type.
vi, ok := v.Interface().(valueInterface)
if !ok {
break
}
v = vi.value
nod = vi.node
}
if nod == nil {
return defaultGen(f)
}
typ := nod.typ
if typ.node != nil || typ.cat != valueT {
return defaultGen(f)
}
meth, _ := typ.rtype.MethodByName(c0.child[1].ident)
return meth.Func
}
}
func genValueRecvIndirect(n *node) func(*frame) reflect.Value {
v := genValueRecv(n)
return func(f *frame) reflect.Value { return v(f).Elem() }
}
func genValueRecv(n *node) func(*frame) reflect.Value {
v := genValue(n.recv.node)
fi := n.recv.index
if len(fi) == 0 {
return v
}
return func(f *frame) reflect.Value {
r := v(f)
if r.Kind() == reflect.Ptr {
r = r.Elem()
}
return r.FieldByIndex(fi)
}
}
func genValueBinRecv(n *node, recv *receiver) func(*frame) reflect.Value {
value := genValue(n)
binValue := genValue(recv.node)
v := func(f *frame) reflect.Value {
if def, ok := value(f).Interface().(*node); ok {
if def != nil && def.recv != nil && def.recv.val.IsValid() {
return def.recv.val
}
}
ival, _ := binValue(f).Interface().(valueInterface)
return ival.value
}
fi := recv.index
if len(fi) == 0 {
return v
}
return func(f *frame) reflect.Value {
r := v(f)
if r.Kind() == reflect.Ptr {
r = r.Elem()
}
return r.FieldByIndex(fi)
}
}
func genValueRecvInterfacePtr(n *node) func(*frame) reflect.Value {
v := genValue(n.recv.node)
fi := n.recv.index
return func(f *frame) reflect.Value {
r := v(f)
r = r.Elem().Elem()
if len(fi) == 0 {
return r
}
if r.Kind() == reflect.Ptr {
r = r.Elem()
}
return r.FieldByIndex(fi)
}
}
func genValueAsFunctionWrapper(n *node) func(*frame) reflect.Value {
value := genValue(n)
typ := n.typ.TypeOf()
return func(f *frame) reflect.Value {
v := value(f)
if v.IsNil() {
return reflect.New(typ).Elem()
}
return genFunctionWrapper(v.Interface().(*node))(f)
}
}
func genValueAs(n *node, t reflect.Type) func(*frame) reflect.Value {
v := genValue(n)
return func(f *frame) reflect.Value {
return v(f).Convert(t)
}
}
func genValue(n *node) func(*frame) reflect.Value {
switch n.kind {
case basicLit:
convertConstantValue(n)
v := n.rval
if !v.IsValid() {
v = reflect.New(interf).Elem()
}
return func(f *frame) reflect.Value { return v }
case funcDecl:
var v reflect.Value
if w, ok := n.val.(reflect.Value); ok {
v = w
} else {
v = reflect.ValueOf(n.val)
}
return func(f *frame) reflect.Value { return v }
default:
if n.rval.IsValid() {
convertConstantValue(n)
v := n.rval
return func(f *frame) reflect.Value { return v }
}
if n.sym != nil {
i := n.sym.index
if i < 0 {
return genValue(n.sym.node)
}
if n.sym.global {
return func(f *frame) reflect.Value { return f.root.data[i] }
}
return valueGenerator(n, i)
}
if n.findex == notInFrame {
var v reflect.Value
if w, ok := n.val.(reflect.Value); ok {
v = w
} else {
v = reflect.ValueOf(n.val)
}
return func(f *frame) reflect.Value { return v }
}
return valueGenerator(n, n.findex)
}
}
func genValueArray(n *node) func(*frame) reflect.Value {
value := genValue(n)
// dereference array pointer, to support array operations on array pointer
if n.typ.TypeOf().Kind() == reflect.Ptr {
return func(f *frame) reflect.Value {
return value(f).Elem()
}
}
return value
}
func genValueRangeArray(n *node) func(*frame) reflect.Value {
value := genValue(n)
switch {
case n.typ.TypeOf().Kind() == reflect.Ptr:
// dereference array pointer, to support array operations on array pointer
return func(f *frame) reflect.Value {
return value(f).Elem()
}
case n.typ.val != nil && n.typ.val.cat == interfaceT:
if len(n.typ.val.field) > 0 {
return func(f *frame) reflect.Value {
val := value(f)
v := []valueInterface{}
for i := 0; i < val.Len(); i++ {
switch av := val.Index(i).Interface().(type) {
case []valueInterface:
v = append(v, av...)
case valueInterface:
v = append(v, av)
default:
panic(n.cfgErrorf("invalid type %v", val.Index(i).Type()))
}
}
return reflect.ValueOf(v)
}
}
// empty interface, do not wrap.
fallthrough
default:
return func(f *frame) reflect.Value {
// This is necessary to prevent changes in the returned
// reflect.Value being reflected back to the value used
// for the range expression.
return reflect.ValueOf(value(f).Interface())
}
}
}
func genValueInterfaceArray(n *node) func(*frame) reflect.Value {
value := genValue(n)
return func(f *frame) reflect.Value {
vi := value(f).Interface().([]valueInterface)
v := reflect.MakeSlice(reflect.TypeOf([]interface{}{}), len(vi), len(vi))
for i, vv := range vi {
v.Index(i).Set(vv.value)
}
return v
}
}
func genValueInterface(n *node) func(*frame) reflect.Value {
value := genValue(n)
return func(f *frame) reflect.Value {
v := value(f)
nod := n
for v.IsValid() {
// traverse interface indirections to find out concrete type
vi, ok := v.Interface().(valueInterface)
if !ok {
break
}
v = vi.value
nod = vi.node
}
// empty interface, do not wrap.
if nod.typ.cat == interfaceT && len(nod.typ.field) == 0 {
return v
}
return reflect.ValueOf(valueInterface{nod, v})
}
}
func zeroInterfaceValue() reflect.Value {
n := &node{kind: basicLit, typ: &itype{cat: nilT, untyped: true}}
v := reflect.New(interf).Elem()
return reflect.ValueOf(valueInterface{n, v})
}
func wantEmptyInterface(n *node) bool {
return n.typ.cat == interfaceT && len(n.typ.field) == 0 ||
n.anc.action == aAssign && n.anc.typ.cat == interfaceT && len(n.anc.typ.field) == 0 ||
n.anc.kind == returnStmt && n.anc.val.(*node).typ.ret[0].cat == interfaceT && len(n.anc.val.(*node).typ.ret[0].field) == 0
}
func genValueOutput(n *node, t reflect.Type) func(*frame) reflect.Value {
value := genValue(n)
switch {
case n.anc.action == aAssign && n.anc.typ.cat == interfaceT:
if len(n.anc.typ.field) == 0 {
// empty interface, do not wrap
return value
}
fallthrough
case n.anc.kind == returnStmt && n.anc.val.(*node).typ.ret[0].cat == interfaceT:
if len(n.anc.val.(*node).typ.ret[0].field) == 0 {
// empty interface, do not wrap
return value
}
// The result of the builtin has to be returned as an interface type.
// Wrap it in a valueInterface and return the dereferenced value.
return func(f *frame) reflect.Value {
d := value(f)
v := reflect.New(t).Elem()
d.Set(reflect.ValueOf(valueInterface{n, v}))
return v
}
}
return value
}
func valueInterfaceValue(v reflect.Value) reflect.Value {
for {
vv, ok := v.Interface().(valueInterface)
if !ok {
break
}
v = vv.value
}
return v
}
func genValueInterfaceValue(n *node) func(*frame) reflect.Value {
value := genValue(n)
return func(f *frame) reflect.Value {
v := value(f)
if v.Interface().(valueInterface).node == nil {
// Uninitialized interface value, set it to a correct zero value.
v.Set(zeroInterfaceValue())
v = value(f)
}
return valueInterfaceValue(v)
}
}
func genValueNode(n *node) func(*frame) reflect.Value {
value := genValue(n)
return func(f *frame) reflect.Value {
return reflect.ValueOf(&node{rval: value(f)})
}
}
func genValueRecursiveInterface(n *node, t reflect.Type) func(*frame) reflect.Value {
value := genValue(n)
return func(f *frame) reflect.Value {
vv := value(f)
v := reflect.New(t).Elem()
toRecursive(v, vv)
return v
}
}
func toRecursive(dest, src reflect.Value) {
if !src.IsValid() {
return
}
switch dest.Kind() {
case reflect.Map:
v := reflect.MakeMapWithSize(dest.Type(), src.Len())
for _, kv := range src.MapKeys() {
vv := reflect.New(dest.Type().Elem()).Elem()
toRecursive(vv, src.MapIndex(kv))
vv.SetMapIndex(kv, vv)
}
dest.Set(v)
case reflect.Slice:
l := src.Len()
v := reflect.MakeSlice(dest.Type(), l, l)
for i := 0; i < l; i++ {
toRecursive(v.Index(i), src.Index(i))
}
dest.Set(v)
case reflect.Ptr:
v := reflect.New(dest.Type().Elem()).Elem()
s := src
if s.Elem().Kind() != reflect.Struct { // In the case of *interface{}, we want *struct{}
s = s.Elem()
}
toRecursive(v, s)
dest.Set(v.Addr())
default:
dest.Set(src)
}
}
func genValueRecursiveInterfacePtrValue(n *node) func(*frame) reflect.Value {
value := genValue(n)
return func(f *frame) reflect.Value {
v := value(f)
if v.IsZero() {
return v
}
return v.Elem().Elem()
}
}
func vInt(v reflect.Value) (i int64) {
if c := vConstantValue(v); c != nil {
i, _ = constant.Int64Val(constant.ToInt(c))
return i
}
switch v.Type().Kind() {
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
i = v.Int()
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
i = int64(v.Uint())
case reflect.Float32, reflect.Float64:
i = int64(v.Float())
case reflect.Complex64, reflect.Complex128:
i = int64(real(v.Complex()))
}
return
}
func vUint(v reflect.Value) (i uint64) {
if c := vConstantValue(v); c != nil {
i, _ = constant.Uint64Val(constant.ToInt(c))
return i
}
switch v.Type().Kind() {
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
i = uint64(v.Int())
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
i = v.Uint()
case reflect.Float32, reflect.Float64:
i = uint64(v.Float())
case reflect.Complex64, reflect.Complex128:
i = uint64(real(v.Complex()))
}
return
}
func vComplex(v reflect.Value) (c complex128) {
if c := vConstantValue(v); c != nil {
c = constant.ToComplex(c)
rel, _ := constant.Float64Val(constant.Real(c))
img, _ := constant.Float64Val(constant.Imag(c))
return complex(rel, img)
}
switch v.Type().Kind() {
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
c = complex(float64(v.Int()), 0)
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
c = complex(float64(v.Uint()), 0)
case reflect.Float32, reflect.Float64:
c = complex(v.Float(), 0)
case reflect.Complex64, reflect.Complex128:
c = v.Complex()
}
return
}
func vFloat(v reflect.Value) (i float64) {
if c := vConstantValue(v); c != nil {
i, _ = constant.Float64Val(constant.ToFloat(c))
return i
}
switch v.Type().Kind() {
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
i = float64(v.Int())
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
i = float64(v.Uint())
case reflect.Float32, reflect.Float64:
i = v.Float()
case reflect.Complex64, reflect.Complex128:
i = real(v.Complex())
}
return
}
func vString(v reflect.Value) (s string) {
if c := vConstantValue(v); c != nil {
s = constant.StringVal(c)
return s
}
return v.String()
}
func vConstantValue(v reflect.Value) (c constant.Value) {
if v.Type().Implements(constVal) {
c = v.Interface().(constant.Value)
}
return
}
func genValueInt(n *node) func(*frame) (reflect.Value, int64) {
value := genValue(n)
switch n.typ.TypeOf().Kind() {
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
return func(f *frame) (reflect.Value, int64) { v := value(f); return v, v.Int() }
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
return func(f *frame) (reflect.Value, int64) { v := value(f); return v, int64(v.Uint()) }
case reflect.Float32, reflect.Float64:
return func(f *frame) (reflect.Value, int64) { v := value(f); return v, int64(v.Float()) }
case reflect.Complex64, reflect.Complex128:
if n.typ.untyped && n.rval.IsValid() && imag(n.rval.Complex()) == 0 {
return func(f *frame) (reflect.Value, int64) { v := value(f); return v, int64(real(v.Complex())) }
}
}
return nil
}
func genValueUint(n *node) func(*frame) (reflect.Value, uint64) {
value := genValue(n)
switch n.typ.TypeOf().Kind() {
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
return func(f *frame) (reflect.Value, uint64) { v := value(f); return v, uint64(v.Int()) }
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
return func(f *frame) (reflect.Value, uint64) { v := value(f); return v, v.Uint() }
case reflect.Float32, reflect.Float64:
return func(f *frame) (reflect.Value, uint64) { v := value(f); return v, uint64(v.Float()) }
case reflect.Complex64, reflect.Complex128:
if n.typ.untyped && n.rval.IsValid() && imag(n.rval.Complex()) == 0 {
return func(f *frame) (reflect.Value, uint64) { v := value(f); return v, uint64(real(v.Complex())) }
}
}
return nil
}
func genValueFloat(n *node) func(*frame) (reflect.Value, float64) {
value := genValue(n)
switch n.typ.TypeOf().Kind() {
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
return func(f *frame) (reflect.Value, float64) { v := value(f); return v, float64(v.Int()) }
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
return func(f *frame) (reflect.Value, float64) { v := value(f); return v, float64(v.Uint()) }
case reflect.Float32, reflect.Float64:
return func(f *frame) (reflect.Value, float64) { v := value(f); return v, v.Float() }
case reflect.Complex64, reflect.Complex128:
if n.typ.untyped && n.rval.IsValid() && imag(n.rval.Complex()) == 0 {
return func(f *frame) (reflect.Value, float64) { v := value(f); return v, real(v.Complex()) }
}
}
return nil
}
func genValueComplex(n *node) func(*frame) reflect.Value {
vc := genComplex(n)
return func(f *frame) reflect.Value { return reflect.ValueOf(vc(f)) }
}
func genComplex(n *node) func(*frame) complex128 {
value := genValue(n)
switch n.typ.TypeOf().Kind() {
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
return func(f *frame) complex128 { return complex(float64(value(f).Int()), 0) }
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
return func(f *frame) complex128 { return complex(float64(value(f).Uint()), 0) }
case reflect.Float32, reflect.Float64:
return func(f *frame) complex128 { return complex(value(f).Float(), 0) }
case reflect.Complex64, reflect.Complex128:
return func(f *frame) complex128 { return value(f).Complex() }
}
return nil
}
func genValueString(n *node) func(*frame) (reflect.Value, string) {
value := genValue(n)
return func(f *frame) (reflect.Value, string) { v := value(f); return v, v.String() }
}