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Diffstat (limited to 'libgo/go/reflect/value.go')
-rw-r--r--libgo/go/reflect/value.go114
1 files changed, 73 insertions, 41 deletions
diff --git a/libgo/go/reflect/value.go b/libgo/go/reflect/value.go
index 7cc4f7f8bfd..a924d8639a2 100644
--- a/libgo/go/reflect/value.go
+++ b/libgo/go/reflect/value.go
@@ -10,7 +10,7 @@ import (
"unsafe"
)
-const ptrSize = unsafe.Sizeof((*byte)(nil))
+const ptrSize = 4 << (^uintptr(0) >> 63) // unsafe.Sizeof(uintptr(0)) but an ideal const
const cannotSet = "cannot set value obtained from unexported struct field"
// Value is the reflection interface to a Go value.
@@ -30,6 +30,10 @@ const cannotSet = "cannot set value obtained from unexported struct field"
// A Value can be used concurrently by multiple goroutines provided that
// the underlying Go value can be used concurrently for the equivalent
// direct operations.
+//
+// Using == on two Values does not compare the underlying values
+// they represent, but rather the contents of the Value structs.
+// To compare two Values, compare the results of the Interface method.
type Value struct {
// typ holds the type of the value represented by a Value.
typ *rtype
@@ -104,7 +108,7 @@ func packEface(v Value) interface{} {
// TODO: pass safe boolean from valueInterface so
// we don't need to copy if safe==true?
c := unsafe_New(t)
- memmove(c, ptr, t.size)
+ typedmemmove(t, c, ptr)
ptr = c
}
e.word = ptr
@@ -173,7 +177,7 @@ type emptyInterface struct {
// nonEmptyInterface is the header for a interface value with methods.
type nonEmptyInterface struct {
- // see ../runtime/iface.c:/Itab
+ // see ../runtime/iface.go:/Itab
itab *struct {
typ *rtype // dynamic concrete type
fun [100000]unsafe.Pointer // method table
@@ -261,7 +265,7 @@ func (v Value) runes() []rune {
return *(*[]rune)(v.ptr)
}
-// CanAddr returns true if the value's address can be obtained with Addr.
+// CanAddr reports whether the value's address can be obtained with Addr.
// Such values are called addressable. A value is addressable if it is
// an element of a slice, an element of an addressable array,
// a field of an addressable struct, or the result of dereferencing a pointer.
@@ -270,11 +274,11 @@ func (v Value) CanAddr() bool {
return v.flag&flagAddr != 0
}
-// CanSet returns true if the value of v can be changed.
+// CanSet reports whether the value of v can be changed.
// A Value can be changed only if it is addressable and was not
// obtained by the use of unexported struct fields.
// If CanSet returns false, calling Set or any type-specific
-// setter (e.g., SetBool, SetInt64) will panic.
+// setter (e.g., SetBool, SetInt) will panic.
func (v Value) CanSet() bool {
return v.flag&(flagAddr|flagRO) == flagAddr
}
@@ -295,8 +299,8 @@ func (v Value) Call(in []Value) []Value {
// CallSlice calls the variadic function v with the input arguments in,
// assigning the slice in[len(in)-1] to v's final variadic argument.
-// For example, if len(in) == 3, v.Call(in) represents the Go call v(in[0], in[1], in[2]...).
-// Call panics if v's Kind is not Func or if v is not variadic.
+// For example, if len(in) == 3, v.CallSlice(in) represents the Go call v(in[0], in[1], in[2]...).
+// CallSlice panics if v's Kind is not Func or if v is not variadic.
// It returns the output results as Values.
// As in Go, each input argument must be assignable to the
// type of the function's corresponding input parameter.
@@ -622,7 +626,7 @@ func (v Value) Field(i int) Value {
// Either flagIndir is set and v.ptr points at struct,
// or flagIndir is not set and v.ptr is the actual struct data.
// In the former case, we want v.ptr + offset.
- // In the latter case, we must be have field.offset = 0,
+ // In the latter case, we must have field.offset = 0,
// so v.ptr + field.offset is still okay.
ptr := unsafe.Pointer(uintptr(v.ptr) + field.offset)
return Value{typ, ptr, fl}
@@ -716,7 +720,7 @@ func (v Value) Index(i int) Value {
}
tt := (*sliceType)(unsafe.Pointer(v.typ))
typ := tt.elem
- val := unsafe.Pointer(uintptr(s.Data) + uintptr(i)*typ.size)
+ val := arrayAt(s.Data, i, typ.size)
fl := flagAddr | flagIndir | v.flag&flagRO | flag(typ.Kind())
return Value{typ, val, fl}
@@ -725,7 +729,7 @@ func (v Value) Index(i int) Value {
if uint(i) >= uint(s.Len) {
panic("reflect: string index out of range")
}
- p := unsafe.Pointer(uintptr(s.Data) + uintptr(i))
+ p := arrayAt(s.Data, i, 1)
fl := v.flag&flagRO | flag(Uint8) | flagIndir
return Value{uint8Type, p, fl}
}
@@ -752,7 +756,7 @@ func (v Value) Int() int64 {
panic(&ValueError{"reflect.Value.Int", v.kind()})
}
-// CanInterface returns true if Interface can be used without panicking.
+// CanInterface reports whether Interface can be used without panicking.
func (v Value) CanInterface() bool {
if v.flag == 0 {
panic(&ValueError{"reflect.Value.CanInterface", Invalid})
@@ -849,7 +853,7 @@ func (v Value) IsNil() bool {
panic(&ValueError{"reflect.Value.IsNil", v.kind()})
}
-// IsValid returns true if v represents a value.
+// IsValid reports whether v represents a value.
// It returns false if v is the zero Value.
// If IsValid returns false, all other methods except String panic.
// Most functions and methods never return an invalid value.
@@ -920,7 +924,7 @@ func (v Value) MapIndex(key Value) Value {
// Copy result so future changes to the map
// won't change the underlying value.
c := unsafe_New(typ)
- memmove(c, e, typ.size)
+ typedmemmove(typ, c, e)
return Value{typ, c, fl | flagIndir}
} else {
return Value{typ, *(*unsafe.Pointer)(e), fl}
@@ -958,7 +962,7 @@ func (v Value) MapKeys() []Value {
// Copy result so future changes to the map
// won't change the underlying value.
c := unsafe_New(keyType)
- memmove(c, key, keyType.size)
+ typedmemmove(keyType, c, key)
a[i] = Value{keyType, c, fl | flagIndir}
} else {
a[i] = Value{keyType, *(*unsafe.Pointer)(key), fl}
@@ -1026,7 +1030,7 @@ func (v Value) NumField() int {
return len(tt.fields)
}
-// OverflowComplex returns true if the complex128 x cannot be represented by v's type.
+// OverflowComplex reports whether the complex128 x cannot be represented by v's type.
// It panics if v's Kind is not Complex64 or Complex128.
func (v Value) OverflowComplex(x complex128) bool {
k := v.kind()
@@ -1039,7 +1043,7 @@ func (v Value) OverflowComplex(x complex128) bool {
panic(&ValueError{"reflect.Value.OverflowComplex", v.kind()})
}
-// OverflowFloat returns true if the float64 x cannot be represented by v's type.
+// OverflowFloat reports whether the float64 x cannot be represented by v's type.
// It panics if v's Kind is not Float32 or Float64.
func (v Value) OverflowFloat(x float64) bool {
k := v.kind()
@@ -1059,7 +1063,7 @@ func overflowFloat32(x float64) bool {
return math.MaxFloat32 < x && x <= math.MaxFloat64
}
-// OverflowInt returns true if the int64 x cannot be represented by v's type.
+// OverflowInt reports whether the int64 x cannot be represented by v's type.
// It panics if v's Kind is not Int, Int8, int16, Int32, or Int64.
func (v Value) OverflowInt(x int64) bool {
k := v.kind()
@@ -1072,7 +1076,7 @@ func (v Value) OverflowInt(x int64) bool {
panic(&ValueError{"reflect.Value.OverflowInt", v.kind()})
}
-// OverflowUint returns true if the uint64 x cannot be represented by v's type.
+// OverflowUint reports whether the uint64 x cannot be represented by v's type.
// It panics if v's Kind is not Uint, Uintptr, Uint8, Uint16, Uint32, or Uint64.
func (v Value) OverflowUint(x uint64) bool {
k := v.kind()
@@ -1194,7 +1198,7 @@ func (v Value) Set(x Value) {
}
x = x.assignTo("reflect.Set", v.typ, target)
if x.flag&flagIndir != 0 {
- memmove(v.ptr, x.ptr, v.typ.size)
+ typedmemmove(v.typ, v.ptr, x.ptr)
} else {
*(*unsafe.Pointer)(v.ptr) = x.ptr
}
@@ -1408,7 +1412,7 @@ func (v Value) Slice(i, j int) Value {
if i < 0 || j < i || j > s.Len {
panic("reflect.Value.Slice: string slice index out of bounds")
}
- t := stringHeader{unsafe.Pointer(uintptr(s.Data) + uintptr(i)), j - i}
+ t := stringHeader{arrayAt(s.Data, i, 1), j - i}
return Value{v.typ, unsafe.Pointer(&t), v.flag}
}
@@ -1424,7 +1428,7 @@ func (v Value) Slice(i, j int) Value {
s.Len = j - i
s.Cap = cap - i
if cap-i > 0 {
- s.Data = unsafe.Pointer(uintptr(base) + uintptr(i)*typ.elem.Size())
+ s.Data = arrayAt(base, i, typ.elem.Size())
} else {
// do not advance pointer, to avoid pointing beyond end of slice
s.Data = base
@@ -1476,7 +1480,7 @@ func (v Value) Slice3(i, j, k int) Value {
s.Len = j - i
s.Cap = k - i
if k-i > 0 {
- s.Data = unsafe.Pointer(uintptr(base) + uintptr(i)*typ.elem.Size())
+ s.Data = arrayAt(base, i, typ.elem.Size())
} else {
// do not advance pointer, to avoid pointing beyond end of slice
s.Data = base
@@ -1490,6 +1494,8 @@ func (v Value) Slice3(i, j, k int) Value {
// String is a special case because of Go's String method convention.
// Unlike the other getters, it does not panic if v's Kind is not String.
// Instead, it returns a string of the form "<T value>" where T is v's type.
+// The fmt package treats Values specially. It does not call their String
+// method implicitly but instead prints the concrete values they hold.
func (v Value) String() string {
switch k := v.kind(); k {
case Invalid:
@@ -1515,7 +1521,7 @@ func (v Value) TryRecv() (x Value, ok bool) {
// TrySend attempts to send x on the channel v but will not block.
// It panics if v's Kind is not Chan.
-// It returns true if the value was sent, false otherwise.
+// It reports whether the value was sent.
// As in Go, x's value must be assignable to the channel's element type.
func (v Value) TrySend(x Value) bool {
v.mustBe(Chan)
@@ -1633,6 +1639,12 @@ func typesMustMatch(what string, t1, t2 Type) {
}
}
+// arrayAt returns the i-th element of p, a C-array whose elements are
+// eltSize wide (in bytes).
+func arrayAt(p unsafe.Pointer, i int, eltSize uintptr) unsafe.Pointer {
+ return unsafe.Pointer(uintptr(p) + uintptr(i)*eltSize)
+}
+
// grow grows the slice s so that it can hold extra more values, allocating
// more capacity if needed. It also returns the old and new slice lengths.
func grow(s Value, extra int) (Value, int, int) {
@@ -1708,27 +1720,23 @@ func Copy(dst, src Value) int {
se := src.typ.Elem()
typesMustMatch("reflect.Copy", de, se)
- n := dst.Len()
- if sn := src.Len(); n > sn {
- n = sn
- }
-
- // Copy via memmove.
- var da, sa unsafe.Pointer
+ var ds, ss sliceHeader
if dk == Array {
- da = dst.ptr
+ ds.Data = dst.ptr
+ ds.Len = dst.Len()
+ ds.Cap = ds.Len
} else {
- da = (*sliceHeader)(dst.ptr).Data
+ ds = *(*sliceHeader)(dst.ptr)
}
- if src.flag&flagIndir == 0 {
- sa = unsafe.Pointer(&src.ptr)
- } else if sk == Array {
- sa = src.ptr
+ if sk == Array {
+ ss.Data = src.ptr
+ ss.Len = src.Len()
+ ss.Cap = ss.Len
} else {
- sa = (*sliceHeader)(src.ptr).Data
+ ss = *(*sliceHeader)(src.ptr)
}
- memmove(da, sa, uintptr(n)*de.Size())
- return n
+
+ return typedslicecopy(de.common(), ds, ss)
}
// A runtimeSelect is a single case passed to rselect.
@@ -2269,7 +2277,7 @@ func cvtDirect(v Value, typ Type) Value {
if f&flagAddr != 0 {
// indirect, mutable word - make a copy
c := unsafe_New(t)
- memmove(c, ptr, t.size)
+ typedmemmove(t, c, ptr)
ptr = c
f &^= flagAddr
}
@@ -2311,17 +2319,41 @@ func chansend(t *rtype, ch unsafe.Pointer, val unsafe.Pointer, nb bool) bool
func makechan(typ *rtype, size uint64) (ch unsafe.Pointer)
func makemap(t *rtype) (m unsafe.Pointer)
+
+//go:noescape
func mapaccess(t *rtype, m unsafe.Pointer, key unsafe.Pointer) (val unsafe.Pointer)
+
func mapassign(t *rtype, m unsafe.Pointer, key, val unsafe.Pointer)
+
+//go:noescape
func mapdelete(t *rtype, m unsafe.Pointer, key unsafe.Pointer)
+
+// m escapes into the return value, but the caller of mapiterinit
+// doesn't let the return value escape.
+//go:noescape
func mapiterinit(t *rtype, m unsafe.Pointer) unsafe.Pointer
+
+//go:noescape
func mapiterkey(it unsafe.Pointer) (key unsafe.Pointer)
+
+//go:noescape
func mapiternext(it unsafe.Pointer)
+
+//go:noescape
func maplen(m unsafe.Pointer) int
func call(typ *rtype, fnaddr unsafe.Pointer, isInterface bool, isMethod bool, params *unsafe.Pointer, results *unsafe.Pointer)
func ifaceE2I(t *rtype, src interface{}, dst unsafe.Pointer)
+// typedmemmove copies a value of type t to dst from src.
+//go:noescape
+func typedmemmove(t *rtype, dst, src unsafe.Pointer)
+
+// typedslicecopy copies a slice of elemType values from src to dst,
+// returning the number of elements copied.
+//go:noescape
+func typedslicecopy(elemType *rtype, dst, src sliceHeader) int
+
//go:noescape
//extern memmove
func memmove(adst, asrc unsafe.Pointer, n uintptr)
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