// typ holds the type of the value represented by a Value.
typ *rtype
- // val holds the 1-word representation of the value.
- // If flag's flagIndir bit is set, then val is a pointer to the data.
- // Otherwise val is a word holding the actual data.
- // When the data is smaller than a word, it begins at
- // the first byte (in the memory address sense) of val.
- // We use unsafe.Pointer so that the garbage collector
- // knows that val could be a pointer.
- val unsafe.Pointer
+ // Pointer-valued data or, if flagIndir is set, pointer to data.
+ // Valid when either flagIndir is set or typ.pointers() is true.
+ ptr unsafe.Pointer
+
+ // Non-pointer-valued data. When the data is smaller
+ // than a word, it begins at the first byte (in the memory
+ // address sense) of this field.
+ // Valid when flagIndir is not set and typ.pointers() is false.
+ scalar uintptr
// flag holds metadata about the value.
// The lowest bits are flag bits:
return Kind((f >> flagKindShift) & flagKindMask)
}
+// pointer returns the underlying pointer represented by v.
+// v.Kind() must be Ptr, Map, Chan, Func, or UnsafePointer
+func (v Value) pointer() unsafe.Pointer {
+ if v.typ.size != ptrSize || !v.typ.pointers() {
+ panic("can't call pointer on a non-pointer Value")
+ }
+ if v.flag&flagIndir != 0 {
+ return *(*unsafe.Pointer)(v.ptr)
+ }
+ return v.ptr
+}
+
+// packEface converts v to the empty interface.
+func packEface(v Value) interface{} {
+ t := v.typ
+ var i interface{}
+ e := (*emptyInterface)(unsafe.Pointer(&i))
+ // First, fill in the data portion of the interface.
+ switch {
+ case t.size > ptrSize:
+ // Value is indirect, and so is the interface we're making.
+ ptr := v.ptr
+ if v.flag&flagAddr != 0 {
+ // 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)
+ ptr = c
+ }
+ e.word = iword(ptr)
+ case v.flag&flagIndir != 0:
+ // Value is indirect, but interface is direct. We need
+ // to load the data at v.ptr into the interface data word.
+ if t.pointers() {
+ e.word = iword(*(*unsafe.Pointer)(v.ptr))
+ } else {
+ e.word = iword(loadScalar(v.ptr, t.size))
+ }
+ default:
+ // Value is direct, and so is the interface.
+ if t.pointers() {
+ e.word = iword(v.ptr)
+ } else {
+ e.word = iword(v.scalar)
+ }
+ }
+ // Now, fill in the type portion. We're very careful here not
+ // to have any operation between the e.word and e.typ assignments
+ // that would let the garbage collector observe the partially-built
+ // interface value.
+ e.typ = t
+ return i
+}
+
+// unpackEface converts the empty interface i to a Value.
+func unpackEface(i interface{}) Value {
+ e := (*emptyInterface)(unsafe.Pointer(&i))
+ // NOTE: don't read e.word until we know whether it is really a pointer or not.
+ t := e.typ
+ if t == nil {
+ return Value{}
+ }
+ f := flag(t.Kind()) << flagKindShift
+ if t.size > ptrSize {
+ return Value{t, unsafe.Pointer(e.word), 0, f | flagIndir}
+ }
+ if t.pointers() {
+ return Value{t, unsafe.Pointer(e.word), 0, f}
+ }
+ return Value{t, nil, uintptr(e.word), f}
+}
+
// A ValueError occurs when a Value method is invoked on
// a Value that does not support it. Such cases are documented
// in the description of each method.
// unsafe.Pointer to represent it, so that if iword appears
// in a struct, the garbage collector knows that might be
// a pointer.
+// TODO: get rid of all occurrences of iword (except in the interface decls below?)
+// We want to get rid of the "feature" that an unsafe.Pointer is sometimes a pointer
+// and sometimes a uintptr.
type iword unsafe.Pointer
+// Get an iword that represents this value.
+// TODO: this function goes away at some point
func (v Value) iword() iword {
- if v.flag&flagIndir != 0 && v.typ.size <= ptrSize {
+ t := v.typ
+ if t == nil {
+ return iword(nil)
+ }
+ if v.flag&flagIndir != 0 {
+ if v.typ.size > ptrSize {
+ return iword(v.ptr)
+ }
// Have indirect but want direct word.
- return loadIword(v.val, v.typ.size)
+ if t.pointers() {
+ return iword(*(*unsafe.Pointer)(v.ptr))
+ }
+ return iword(loadScalar(v.ptr, v.typ.size))
+ }
+ if t.pointers() {
+ return iword(v.ptr)
}
- return iword(v.val)
+ return iword(v.scalar)
}
-// loadIword loads n bytes at p from memory into an iword.
-func loadIword(p unsafe.Pointer, n uintptr) iword {
+// Build a Value from a type/iword pair, plus any extra flags.
+// TODO: this function goes away at some point
+func fromIword(t *rtype, w iword, fl flag) Value {
+ fl |= flag(t.Kind()) << flagKindShift
+ if t.size > ptrSize {
+ return Value{t, unsafe.Pointer(w), 0, fl | flagIndir}
+ } else if t.pointers() {
+ return Value{t, unsafe.Pointer(w), 0, fl}
+ } else {
+ return Value{t, nil, uintptr(w), fl}
+ }
+}
+
+// loadScalar loads n bytes at p from memory into a uintptr
+// that forms the second word of an interface. The data
+// must be non-pointer in nature.
+func loadScalar(p unsafe.Pointer, n uintptr) uintptr {
// Run the copy ourselves instead of calling memmove
// to avoid moving w to the heap.
- var w iword
+ var w uintptr
switch n {
default:
- panic("reflect: internal error: loadIword of " + strconv.Itoa(int(n)) + "-byte value")
+ panic("reflect: internal error: loadScalar of " + strconv.Itoa(int(n)) + "-byte value")
case 0:
case 1:
*(*uint8)(unsafe.Pointer(&w)) = *(*uint8)(p)
return w
}
-// storeIword stores n bytes from w into p.
-func storeIword(p unsafe.Pointer, w iword, n uintptr) {
+// storeScalar stores n bytes from w into p.
+func storeScalar(p unsafe.Pointer, w uintptr, n uintptr) {
// Run the copy ourselves instead of calling memmove
// to avoid moving w to the heap.
switch n {
default:
- panic("reflect: internal error: storeIword of " + strconv.Itoa(int(n)) + "-byte value")
+ panic("reflect: internal error: storeScalar of " + strconv.Itoa(int(n)) + "-byte value")
case 0:
case 1:
*(*uint8)(p) = *(*uint8)(unsafe.Pointer(&w))
if v.flag&flagAddr == 0 {
panic("reflect.Value.Addr of unaddressable value")
}
- return Value{v.typ.ptrTo(), v.val, (v.flag & flagRO) | flag(Ptr)<<flagKindShift}
+ return Value{v.typ.ptrTo(), v.ptr, 0, (v.flag & flagRO) | flag(Ptr)<<flagKindShift}
}
// Bool returns v's underlying value.
func (v Value) Bool() bool {
v.mustBe(Bool)
if v.flag&flagIndir != 0 {
- return *(*bool)(v.val)
+ return *(*bool)(v.ptr)
}
- return *(*bool)(unsafe.Pointer(&v.val))
+ return *(*bool)(unsafe.Pointer(&v.scalar))
}
// Bytes returns v's underlying value.
panic("reflect.Value.Bytes of non-byte slice")
}
// Slice is always bigger than a word; assume flagIndir.
- return *(*[]byte)(v.val)
+ return *(*[]byte)(v.ptr)
}
// runes returns v's underlying value.
panic("reflect.Value.Bytes of non-rune slice")
}
// Slice is always bigger than a word; assume flagIndir.
- return *(*[]rune)(v.val)
+ return *(*[]rune)(v.ptr)
}
// CanAddr returns true if the value's address can be obtained with Addr.
if v.flag&flagMethod != 0 {
t, fn, rcvr = methodReceiver(op, v, int(v.flag)>>flagMethodShift)
} else if v.flag&flagIndir != 0 {
- fn = *(*unsafe.Pointer)(v.val)
+ fn = *(*unsafe.Pointer)(v.ptr)
} else {
- fn = v.val
+ fn = v.ptr
}
if fn == nil {
n := targ.size
addr := unsafe.Pointer(uintptr(ptr) + off)
v = v.assignTo("reflect.Value.Call", targ, (*interface{})(addr))
- if v.flag&flagIndir == 0 {
- storeIword(addr, iword(v.val), n)
+ if v.flag&flagIndir != 0 {
+ memmove(addr, v.ptr, n)
+ } else if targ.pointers() {
+ *(*unsafe.Pointer)(addr) = v.ptr
} else {
- memmove(addr, v.val, n)
+ storeScalar(addr, v.scalar, n)
}
off += n
}
a := uintptr(tv.Align())
off = (off + a - 1) &^ (a - 1)
fl := flagIndir | flag(tv.Kind())<<flagKindShift
- ret[i] = Value{tv.common(), unsafe.Pointer(uintptr(ptr) + off), fl}
+ ret[i] = Value{tv.common(), unsafe.Pointer(uintptr(ptr) + off), 0, fl}
off += tv.Size()
}
for _, arg := range ftyp.in {
typ := arg
off += -off & uintptr(typ.align-1)
- v := Value{typ, nil, flag(typ.Kind()) << flagKindShift}
- if typ.size <= ptrSize {
- // value fits in word.
- v.val = unsafe.Pointer(loadIword(unsafe.Pointer(uintptr(ptr)+off), typ.size))
- } else {
+ addr := unsafe.Pointer(uintptr(ptr) + off)
+ v := Value{typ, nil, 0, flag(typ.Kind()) << flagKindShift}
+ if typ.size > ptrSize {
// value does not fit in word.
// Must make a copy, because f might keep a reference to it,
// and we cannot let f keep a reference to the stack frame
// after this function returns, not even a read-only reference.
- v.val = unsafe_New(typ)
- memmove(v.val, unsafe.Pointer(uintptr(ptr)+off), typ.size)
+ v.ptr = unsafe_New(typ)
+ memmove(v.ptr, addr, typ.size)
v.flag |= flagIndir
+ } else if typ.pointers() {
+ v.ptr = *(*unsafe.Pointer)(addr)
+ } else {
+ v.scalar = loadScalar(addr, typ.size)
}
in = append(in, v)
off += typ.size
}
off += -off & uintptr(typ.align-1)
addr := unsafe.Pointer(uintptr(ptr) + off)
- if v.flag&flagIndir == 0 {
- storeIword(addr, iword(v.val), typ.size)
+ if v.flag&flagIndir != 0 {
+ memmove(addr, v.ptr, typ.size)
+ } else if typ.pointers() {
+ *(*unsafe.Pointer)(addr) = v.ptr
} else {
- memmove(addr, v.val, typ.size)
+ storeScalar(addr, v.scalar, typ.size)
}
off += typ.size
}
panic("reflect: " + op + " of unexported method")
}
t = m.typ
- iface := (*nonEmptyInterface)(v.val)
+ iface := (*nonEmptyInterface)(v.ptr)
if iface.itab == nil {
panic("reflect: " + op + " of method on nil interface value")
}
case Array:
return v.typ.Len()
case Chan:
- return int(chancap(v.iword()))
+ return int(chancap(v.pointer()))
case Slice:
// Slice is always bigger than a word; assume flagIndir.
- return (*SliceHeader)(v.val).Cap
+ return (*sliceHeader)(v.ptr).Cap
}
panic(&ValueError{"reflect.Value.Cap", k})
}
func (v Value) Close() {
v.mustBe(Chan)
v.mustBeExported()
- chanclose(v.iword())
+ chanclose(v.pointer())
}
// Complex returns v's underlying value, as a complex128.
switch k {
case Complex64:
if v.flag&flagIndir != 0 {
- return complex128(*(*complex64)(v.val))
+ return complex128(*(*complex64)(v.ptr))
}
- return complex128(*(*complex64)(unsafe.Pointer(&v.val)))
+ return complex128(*(*complex64)(unsafe.Pointer(&v.scalar)))
case Complex128:
// complex128 is always bigger than a word; assume flagIndir.
- return *(*complex128)(v.val)
+ return *(*complex128)(v.ptr)
}
panic(&ValueError{"reflect.Value.Complex", k})
}
k := v.kind()
switch k {
case Interface:
- var (
- typ *rtype
- val unsafe.Pointer
- )
+ var eface interface{}
if v.typ.NumMethod() == 0 {
- eface := (*emptyInterface)(v.val)
- if eface.typ == nil {
- // nil interface value
- return Value{}
- }
- typ = eface.typ
- val = unsafe.Pointer(eface.word)
+ eface = *(*interface{})(v.ptr)
} else {
- iface := (*nonEmptyInterface)(v.val)
- if iface.itab == nil {
- // nil interface value
- return Value{}
- }
- typ = iface.itab.typ
- val = unsafe.Pointer(iface.word)
+ eface = (interface{})(*(*interface {
+ M()
+ })(v.ptr))
}
- fl := v.flag & flagRO
- fl |= flag(typ.Kind()) << flagKindShift
- if typ.size > ptrSize {
- fl |= flagIndir
- }
- return Value{typ, val, fl}
-
+ x := unpackEface(eface)
+ x.flag |= v.flag & flagRO
+ return x
case Ptr:
- val := v.val
+ ptr := v.ptr
if v.flag&flagIndir != 0 {
- val = *(*unsafe.Pointer)(val)
+ ptr = *(*unsafe.Pointer)(ptr)
}
// The returned value's address is v's value.
- if val == nil {
+ if ptr == nil {
return Value{}
}
tt := (*ptrType)(unsafe.Pointer(v.typ))
typ := tt.elem
fl := v.flag&flagRO | flagIndir | flagAddr
fl |= flag(typ.Kind() << flagKindShift)
- return Value{typ, val, fl}
+ return Value{typ, ptr, 0, fl}
}
panic(&ValueError{"reflect.Value.Elem", k})
}
}
fl |= flag(typ.Kind()) << flagKindShift
- var val unsafe.Pointer
+ var ptr unsafe.Pointer
+ var scalar uintptr
switch {
case fl&flagIndir != 0:
// Indirect. Just bump pointer.
- val = unsafe.Pointer(uintptr(v.val) + field.offset)
+ ptr = unsafe.Pointer(uintptr(v.ptr) + field.offset)
+ case typ.pointers():
+ if field.offset != 0 {
+ panic("field access of ptr value isn't at offset 0")
+ }
+ ptr = v.ptr
case bigEndian:
- // Direct. Discard leading bytes.
- val = unsafe.Pointer(uintptr(v.val) << (field.offset * 8))
+ // Must be scalar. Discard leading bytes.
+ scalar = v.scalar << (field.offset * 8)
default:
- // Direct. Discard leading bytes.
- val = unsafe.Pointer(uintptr(v.val) >> (field.offset * 8))
+ // Must be scalar. Discard leading bytes.
+ scalar = v.scalar >> (field.offset * 8)
}
- return Value{typ, val, fl}
+ return Value{typ, ptr, scalar, fl}
}
// FieldByIndex returns the nested field corresponding to index.
switch k {
case Float32:
if v.flag&flagIndir != 0 {
- return float64(*(*float32)(v.val))
+ return float64(*(*float32)(v.ptr))
}
- return float64(*(*float32)(unsafe.Pointer(&v.val)))
+ return float64(*(*float32)(unsafe.Pointer(&v.scalar)))
case Float64:
if v.flag&flagIndir != 0 {
- return *(*float64)(v.val)
+ return *(*float64)(v.ptr)
}
- return *(*float64)(unsafe.Pointer(&v.val))
+ return *(*float64)(unsafe.Pointer(&v.scalar))
}
panic(&ValueError{"reflect.Value.Float", k})
}
offset := uintptr(i) * typ.size
var val unsafe.Pointer
+ var scalar uintptr
switch {
case fl&flagIndir != 0:
// Indirect. Just bump pointer.
- val = unsafe.Pointer(uintptr(v.val) + offset)
+ val = unsafe.Pointer(uintptr(v.ptr) + offset)
+ case typ.pointers():
+ if offset != 0 {
+ panic("can't Index(i) with i!=0 on ptrLike value")
+ }
+ val = v.ptr
case bigEndian:
// Direct. Discard leading bytes.
- val = unsafe.Pointer(uintptr(v.val) << (offset * 8))
+ scalar = v.scalar << (offset * 8)
default:
// Direct. Discard leading bytes.
- val = unsafe.Pointer(uintptr(v.val) >> (offset * 8))
+ scalar = v.scalar >> (offset * 8)
}
- return Value{typ, val, fl}
+ return Value{typ, val, scalar, fl}
case Slice:
// Element flag same as Elem of Ptr.
// Addressable, indirect, possibly read-only.
fl := flagAddr | flagIndir | v.flag&flagRO
- s := (*SliceHeader)(v.val)
+ s := (*sliceHeader)(v.ptr)
if i < 0 || i >= s.Len {
panic("reflect: slice index out of range")
}
tt := (*sliceType)(unsafe.Pointer(v.typ))
typ := tt.elem
fl |= flag(typ.Kind()) << flagKindShift
- val := unsafe.Pointer(s.Data + uintptr(i)*typ.size)
- return Value{typ, val, fl}
+ val := unsafe.Pointer(uintptr(s.Data) + uintptr(i)*typ.size)
+ return Value{typ, val, 0, fl}
case String:
fl := v.flag&flagRO | flag(Uint8<<flagKindShift)
- s := (*StringHeader)(v.val)
+ s := (*stringHeader)(v.ptr)
if i < 0 || i >= s.Len {
panic("reflect: string index out of range")
}
- val := *(*byte)(unsafe.Pointer(s.Data + uintptr(i)))
- return Value{uint8Type, unsafe.Pointer(uintptr(val)), fl}
+ b := uintptr(0)
+ *(*byte)(unsafe.Pointer(&b)) = *(*byte)(unsafe.Pointer(uintptr(s.Data) + uintptr(i)))
+ return Value{uint8Type, nil, b, fl}
}
panic(&ValueError{"reflect.Value.Index", k})
}
k := v.kind()
var p unsafe.Pointer
if v.flag&flagIndir != 0 {
- p = v.val
+ p = v.ptr
} else {
- // The escape analysis is good enough that &v.val
+ // The escape analysis is good enough that &v.scalar
// does not trigger a heap allocation.
- p = unsafe.Pointer(&v.val)
+ p = unsafe.Pointer(&v.scalar)
}
switch k {
case Int:
v = makeMethodValue("Interface", v)
}
- k := v.kind()
- if k == Interface {
+ if v.kind() == Interface {
// Special case: return the element inside the interface.
// Empty interface has one layout, all interfaces with
// methods have a second layout.
if v.NumMethod() == 0 {
- return *(*interface{})(v.val)
+ return *(*interface{})(v.ptr)
}
return *(*interface {
M()
- })(v.val)
- }
-
- // Non-interface value.
- var eface emptyInterface
- eface.typ = v.typ
- eface.word = v.iword()
-
- // Don't need to allocate if v is not addressable or fits in one word.
- if v.flag&flagAddr != 0 && v.typ.size > ptrSize {
- // eface.word is a pointer to the actual data,
- // which might be changed. We need to return
- // a pointer to unchanging data, so make a copy.
- ptr := unsafe_New(v.typ)
- memmove(ptr, unsafe.Pointer(eface.word), v.typ.size)
- eface.word = iword(ptr)
+ })(v.ptr)
}
- return *(*interface{})(unsafe.Pointer(&eface))
+ // TODO: pass safe to packEface so we don't need to copy if safe==true?
+ return packEface(v)
}
// InterfaceData returns the interface v's value as a uintptr pair.
// It panics if v's Kind is not Interface.
func (v Value) InterfaceData() [2]uintptr {
+ // TODO: deprecate this
v.mustBe(Interface)
// We treat this as a read operation, so we allow
// it even for unexported data, because the caller
// has to import "unsafe" to turn it into something
// that can be abused.
// Interface value is always bigger than a word; assume flagIndir.
- return *(*[2]uintptr)(v.val)
+ return *(*[2]uintptr)(v.ptr)
}
// IsNil returns true if v is a nil value.
if v.flag&flagMethod != 0 {
return false
}
- ptr := v.val
+ ptr := v.ptr
if v.flag&flagIndir != 0 {
ptr = *(*unsafe.Pointer)(ptr)
}
case Interface, Slice:
// Both interface and slice are nil if first word is 0.
// Both are always bigger than a word; assume flagIndir.
- return *(*unsafe.Pointer)(v.val) == nil
+ return *(*unsafe.Pointer)(v.ptr) == nil
}
panic(&ValueError{"reflect.Value.IsNil", k})
}
tt := (*arrayType)(unsafe.Pointer(v.typ))
return int(tt.len)
case Chan:
- return chanlen(v.iword())
+ return chanlen(v.pointer())
case Map:
- return maplen(v.iword())
+ return maplen(v.pointer())
case Slice:
// Slice is bigger than a word; assume flagIndir.
- return (*SliceHeader)(v.val).Len
+ return (*sliceHeader)(v.ptr).Len
case String:
// String is bigger than a word; assume flagIndir.
- return (*StringHeader)(v.val).Len
+ return (*stringHeader)(v.ptr).Len
}
panic(&ValueError{"reflect.Value.Len", k})
}
// of unexported fields.
key = key.assignTo("reflect.Value.MapIndex", tt.key, nil)
- word, ok := mapaccess(v.typ, v.iword(), key.iword())
- if !ok {
+ var k unsafe.Pointer
+ if key.flag&flagIndir != 0 {
+ k = key.ptr
+ } else if key.typ.pointers() {
+ k = unsafe.Pointer(&key.ptr)
+ } else {
+ k = unsafe.Pointer(&key.scalar)
+ }
+ e := mapaccess(v.typ, v.pointer(), k)
+ if e == nil {
return Value{}
}
typ := tt.elem
fl := (v.flag | key.flag) & flagRO
+ fl |= flag(typ.Kind()) << flagKindShift
if typ.size > ptrSize {
- fl |= flagIndir
+ // Copy result so future changes to the map
+ // won't change the underlying value.
+ c := unsafe_New(typ)
+ memmove(c, e, typ.size)
+ return Value{typ, c, 0, fl | flagIndir}
+ } else if typ.pointers() {
+ return Value{typ, *(*unsafe.Pointer)(e), 0, fl}
+ } else {
+ return Value{typ, nil, loadScalar(e, typ.size), fl}
}
- fl |= flag(typ.Kind()) << flagKindShift
- return Value{typ, unsafe.Pointer(word), fl}
}
// MapKeys returns a slice containing all the keys present in the map,
tt := (*mapType)(unsafe.Pointer(v.typ))
keyType := tt.key
- fl := v.flag & flagRO
- fl |= flag(keyType.Kind()) << flagKindShift
- if keyType.size > ptrSize {
- fl |= flagIndir
- }
+ fl := v.flag&flagRO | flag(keyType.Kind())<<flagKindShift
- m := v.iword()
+ m := v.pointer()
mlen := int(0)
if m != nil {
mlen = maplen(m)
a := make([]Value, mlen)
var i int
for i = 0; i < len(a); i++ {
- keyWord, ok := mapiterkey(it)
- if !ok {
+ key := mapiterkey(it)
+ if key == nil {
+ // Someone deleted an entry from the map since we
+ // called maplen above. It's a data race, but nothing
+ // we can do about it.
break
}
- a[i] = Value{keyType, unsafe.Pointer(keyWord), fl}
+ if keyType.size > ptrSize {
+ // Copy result so future changes to the map
+ // won't change the underlying value.
+ c := unsafe_New(keyType)
+ memmove(c, key, keyType.size)
+ a[i] = Value{keyType, c, 0, fl | flagIndir}
+ } else if keyType.pointers() {
+ a[i] = Value{keyType, *(*unsafe.Pointer)(key), 0, fl}
+ } else {
+ a[i] = Value{keyType, nil, loadScalar(key, keyType.size), fl}
+ }
mapiternext(it)
}
return a[:i]
fl := v.flag & (flagRO | flagIndir)
fl |= flag(Func) << flagKindShift
fl |= flag(i)<<flagMethodShift | flagMethod
- return Value{v.typ, v.val, fl}
+ return Value{v.typ, v.ptr, v.scalar, fl}
}
// NumMethod returns the number of methods in the value's method set.
// code pointer, but not necessarily enough to identify a
// single function uniquely. The only guarantee is that the
// result is zero if and only if v is a nil func Value.
+//
+// If v's Kind is Slice, the returned pointer is to the first
+// element of the slice. If the slice is nil the returned value
+// is 0. If the slice is empty but non-nil the return value is non-zero.
func (v Value) Pointer() uintptr {
+ // TODO: deprecate
k := v.kind()
switch k {
case Chan, Map, Ptr, UnsafePointer:
- p := v.val
- if v.flag&flagIndir != 0 {
- p = *(*unsafe.Pointer)(p)
- }
- return uintptr(p)
+ return uintptr(v.pointer())
case Func:
if v.flag&flagMethod != 0 {
// As the doc comment says, the returned pointer is an
f := methodValueCall
return **(**uintptr)(unsafe.Pointer(&f))
}
- p := v.val
- if v.flag&flagIndir != 0 {
- p = *(*unsafe.Pointer)(p)
- }
+ p := v.pointer()
// Non-nil func value points at data block.
// First word of data block is actual code.
if p != nil {
return uintptr(p)
case Slice:
- return (*SliceHeader)(v.val).Data
+ return (*SliceHeader)(v.ptr).Data
}
panic(&ValueError{"reflect.Value.Pointer", k})
}
if ChanDir(tt.dir)&RecvDir == 0 {
panic("reflect: recv on send-only channel")
}
- word, selected, ok := chanrecv(v.typ, v.iword(), nb)
+ word, selected, ok := chanrecv(v.typ, v.pointer(), nb)
if selected {
- typ := tt.elem
- fl := flag(typ.Kind()) << flagKindShift
- if typ.size > ptrSize {
- fl |= flagIndir
- }
- val = Value{typ, unsafe.Pointer(word), fl}
+ val = fromIword(tt.elem, word, 0)
}
return
}
}
x.mustBeExported()
x = x.assignTo("reflect.Value.Send", tt.elem, nil)
- return chansend(v.typ, v.iword(), x.iword(), nb)
+ return chansend(v.typ, v.pointer(), x.iword(), nb)
}
// Set assigns x to the value v.
x.mustBeExported() // do not let unexported x leak
var target *interface{}
if v.kind() == Interface {
- target = (*interface{})(v.val)
+ target = (*interface{})(v.ptr)
}
x = x.assignTo("reflect.Set", v.typ, target)
if x.flag&flagIndir != 0 {
- memmove(v.val, x.val, v.typ.size)
+ memmove(v.ptr, x.ptr, v.typ.size)
+ } else if x.typ.pointers() {
+ *(*unsafe.Pointer)(v.ptr) = x.ptr
} else {
- storeIword(v.val, iword(x.val), v.typ.size)
+ memmove(v.ptr, unsafe.Pointer(&x.scalar), v.typ.size)
}
}
func (v Value) SetBool(x bool) {
v.mustBeAssignable()
v.mustBe(Bool)
- *(*bool)(v.val) = x
+ *(*bool)(v.ptr) = x
}
// SetBytes sets v's underlying value.
if v.typ.Elem().Kind() != Uint8 {
panic("reflect.Value.SetBytes of non-byte slice")
}
- *(*[]byte)(v.val) = x
+ *(*[]byte)(v.ptr) = x
}
// setRunes sets v's underlying value.
if v.typ.Elem().Kind() != Int32 {
panic("reflect.Value.setRunes of non-rune slice")
}
- *(*[]rune)(v.val) = x
+ *(*[]rune)(v.ptr) = x
}
// SetComplex sets v's underlying value to x.
default:
panic(&ValueError{"reflect.Value.SetComplex", k})
case Complex64:
- *(*complex64)(v.val) = complex64(x)
+ *(*complex64)(v.ptr) = complex64(x)
case Complex128:
- *(*complex128)(v.val) = x
+ *(*complex128)(v.ptr) = x
}
}
default:
panic(&ValueError{"reflect.Value.SetFloat", k})
case Float32:
- *(*float32)(v.val) = float32(x)
+ *(*float32)(v.ptr) = float32(x)
case Float64:
- *(*float64)(v.val) = x
+ *(*float64)(v.ptr) = x
}
}
default:
panic(&ValueError{"reflect.Value.SetInt", k})
case Int:
- *(*int)(v.val) = int(x)
+ *(*int)(v.ptr) = int(x)
case Int8:
- *(*int8)(v.val) = int8(x)
+ *(*int8)(v.ptr) = int8(x)
case Int16:
- *(*int16)(v.val) = int16(x)
+ *(*int16)(v.ptr) = int16(x)
case Int32:
- *(*int32)(v.val) = int32(x)
+ *(*int32)(v.ptr) = int32(x)
case Int64:
- *(*int64)(v.val) = x
+ *(*int64)(v.ptr) = x
}
}
func (v Value) SetLen(n int) {
v.mustBeAssignable()
v.mustBe(Slice)
- s := (*SliceHeader)(v.val)
+ s := (*sliceHeader)(v.ptr)
if n < 0 || n > int(s.Cap) {
panic("reflect: slice length out of range in SetLen")
}
func (v Value) SetCap(n int) {
v.mustBeAssignable()
v.mustBe(Slice)
- s := (*SliceHeader)(v.val)
+ s := (*sliceHeader)(v.ptr)
if n < int(s.Len) || n > int(s.Cap) {
panic("reflect: slice capacity out of range in SetCap")
}
key.mustBeExported()
tt := (*mapType)(unsafe.Pointer(v.typ))
key = key.assignTo("reflect.Value.SetMapIndex", tt.key, nil)
- if val.typ != nil {
- val.mustBeExported()
- val = val.assignTo("reflect.Value.SetMapIndex", tt.elem, nil)
+ var k unsafe.Pointer
+ if key.flag&flagIndir != 0 {
+ k = key.ptr
+ } else if key.typ.pointers() {
+ k = unsafe.Pointer(&key.ptr)
+ } else {
+ k = unsafe.Pointer(&key.scalar)
+ }
+ if val.typ == nil {
+ mapdelete(v.typ, v.pointer(), k)
+ return
+ }
+ val.mustBeExported()
+ val = val.assignTo("reflect.Value.SetMapIndex", tt.elem, nil)
+ var e unsafe.Pointer
+ if val.flag&flagIndir != 0 {
+ e = val.ptr
+ } else if val.typ.pointers() {
+ e = unsafe.Pointer(&val.ptr)
+ } else {
+ e = unsafe.Pointer(&val.scalar)
}
- mapassign(v.typ, v.iword(), key.iword(), val.iword(), val.typ != nil)
+ mapassign(v.typ, v.pointer(), k, e)
}
// SetUint sets v's underlying value to x.
default:
panic(&ValueError{"reflect.Value.SetUint", k})
case Uint:
- *(*uint)(v.val) = uint(x)
+ *(*uint)(v.ptr) = uint(x)
case Uint8:
- *(*uint8)(v.val) = uint8(x)
+ *(*uint8)(v.ptr) = uint8(x)
case Uint16:
- *(*uint16)(v.val) = uint16(x)
+ *(*uint16)(v.ptr) = uint16(x)
case Uint32:
- *(*uint32)(v.val) = uint32(x)
+ *(*uint32)(v.ptr) = uint32(x)
case Uint64:
- *(*uint64)(v.val) = x
+ *(*uint64)(v.ptr) = x
case Uintptr:
- *(*uintptr)(v.val) = uintptr(x)
+ *(*uintptr)(v.ptr) = uintptr(x)
}
}
func (v Value) SetPointer(x unsafe.Pointer) {
v.mustBeAssignable()
v.mustBe(UnsafePointer)
- *(*unsafe.Pointer)(v.val) = x
+ *(*unsafe.Pointer)(v.ptr) = x
}
// SetString sets v's underlying value to x.
func (v Value) SetString(x string) {
v.mustBeAssignable()
v.mustBe(String)
- *(*string)(v.val) = x
+ *(*string)(v.ptr) = x
}
// Slice returns v[i:j].
tt := (*arrayType)(unsafe.Pointer(v.typ))
cap = int(tt.len)
typ = (*sliceType)(unsafe.Pointer(tt.slice))
- base = v.val
+ base = v.ptr
case Slice:
typ = (*sliceType)(unsafe.Pointer(v.typ))
- s := (*SliceHeader)(v.val)
+ s := (*sliceHeader)(v.ptr)
base = unsafe.Pointer(s.Data)
cap = s.Cap
case String:
- s := (*StringHeader)(v.val)
+ s := (*stringHeader)(v.ptr)
if i < 0 || j < i || j > s.Len {
panic("reflect.Value.Slice: string slice index out of bounds")
}
- var x string
- val := (*StringHeader)(unsafe.Pointer(&x))
- val.Data = s.Data + uintptr(i)
- val.Len = j - i
- return Value{v.typ, unsafe.Pointer(&x), v.flag}
+ t := stringHeader{unsafe.Pointer(uintptr(s.Data) + uintptr(i)), j - i}
+ return Value{v.typ, unsafe.Pointer(&t), 0, v.flag}
}
if i < 0 || j < i || j > cap {
// Declare slice so that gc can see the base pointer in it.
var x []unsafe.Pointer
- // Reinterpret as *SliceHeader to edit.
- s := (*SliceHeader)(unsafe.Pointer(&x))
- s.Data = uintptr(base) + uintptr(i)*typ.elem.Size()
+ // Reinterpret as *sliceHeader to edit.
+ s := (*sliceHeader)(unsafe.Pointer(&x))
+ s.Data = unsafe.Pointer(uintptr(base) + uintptr(i)*typ.elem.Size())
s.Len = j - i
s.Cap = cap - i
fl := v.flag&flagRO | flagIndir | flag(Slice)<<flagKindShift
- return Value{typ.common(), unsafe.Pointer(&x), fl}
+ return Value{typ.common(), unsafe.Pointer(&x), 0, fl}
}
// Slice3 is the 3-index form of the slice operation: it returns v[i:j:k].
tt := (*arrayType)(unsafe.Pointer(v.typ))
cap = int(tt.len)
typ = (*sliceType)(unsafe.Pointer(tt.slice))
- base = v.val
+ base = v.ptr
case Slice:
typ = (*sliceType)(unsafe.Pointer(v.typ))
- s := (*SliceHeader)(v.val)
- base = unsafe.Pointer(s.Data)
+ s := (*sliceHeader)(v.ptr)
+ base = s.Data
cap = s.Cap
}
// can see the base pointer in it.
var x []unsafe.Pointer
- // Reinterpret as *SliceHeader to edit.
- s := (*SliceHeader)(unsafe.Pointer(&x))
- s.Data = uintptr(base) + uintptr(i)*typ.elem.Size()
+ // Reinterpret as *sliceHeader to edit.
+ s := (*sliceHeader)(unsafe.Pointer(&x))
+ s.Data = unsafe.Pointer(uintptr(base) + uintptr(i)*typ.elem.Size())
s.Len = j - i
s.Cap = k - i
fl := v.flag&flagRO | flagIndir | flag(Slice)<<flagKindShift
- return Value{typ.common(), unsafe.Pointer(&x), fl}
+ return Value{typ.common(), unsafe.Pointer(&x), 0, fl}
}
// String returns the string v's underlying value, as a string.
case Invalid:
return "<invalid Value>"
case String:
- return *(*string)(v.val)
+ return *(*string)(v.ptr)
}
// If you call String on a reflect.Value of other type, it's better to
// print something than to panic. Useful in debugging.
k := v.kind()
var p unsafe.Pointer
if v.flag&flagIndir != 0 {
- p = v.val
+ p = v.ptr
} else {
- // The escape analysis is good enough that &v.val
+ // The escape analysis is good enough that &v.scalar
// does not trigger a heap allocation.
- p = unsafe.Pointer(&v.val)
+ p = unsafe.Pointer(&v.scalar)
}
switch k {
case Uint:
// It is for advanced clients that also import the "unsafe" package.
// It panics if v is not addressable.
func (v Value) UnsafeAddr() uintptr {
+ // TODO: deprecate
if v.typ == nil {
panic(&ValueError{"reflect.Value.UnsafeAddr", Invalid})
}
if v.flag&flagAddr == 0 {
panic("reflect.Value.UnsafeAddr of unaddressable value")
}
- return uintptr(v.val)
+ return uintptr(v.ptr)
}
// StringHeader is the runtime representation of a string.
Len int
}
+// stringHeader is a safe version of StringHeader used within this package.
+type stringHeader struct {
+ Data unsafe.Pointer
+ Len int
+}
+
// SliceHeader is the runtime representation of a slice.
// It cannot be used safely or portably and its representation may
// change in a later release.
Cap int
}
+// sliceHeader is a safe version of SliceHeader used within this package.
+type sliceHeader struct {
+ Data unsafe.Pointer
+ Len int
+ Cap int
+}
+
func typesMustMatch(what string, t1, t2 Type) {
if t1 != t2 {
panic(what + ": " + t1.String() + " != " + t2.String())
// If sk is an in-line array, cannot take its address.
// Instead, copy element by element.
+ // TODO: memmove would be ok for this (sa = unsafe.Pointer(&v.scalar))
+ // if we teach the compiler that ptrs don't escape from memmove.
if src.flag&flagIndir == 0 {
for i := 0; i < n; i++ {
dst.Index(i).Set(src.Index(i))
// Copy via memmove.
var da, sa unsafe.Pointer
if dk == Array {
- da = dst.val
+ da = dst.ptr
} else {
- da = unsafe.Pointer((*SliceHeader)(dst.val).Data)
+ da = (*sliceHeader)(dst.ptr).Data
}
if sk == Array {
- sa = src.val
+ sa = src.ptr
} else {
- sa = unsafe.Pointer((*SliceHeader)(src.val).Data)
+ sa = (*sliceHeader)(src.ptr).Data
}
memmove(da, sa, uintptr(n)*de.Size())
return n
chosen, word, recvOK := rselect(runcases)
if runcases[chosen].dir == uintptr(SelectRecv) {
tt := (*chanType)(unsafe.Pointer(runcases[chosen].typ))
- typ := tt.elem
- fl := flag(typ.Kind()) << flagKindShift
- if typ.size > ptrSize {
- fl |= flagIndir
- }
- recv = Value{typ, unsafe.Pointer(word), fl}
+ recv = fromIword(tt.elem, word, 0)
}
return chosen, recv, recvOK
}
panic("reflect.MakeSlice: len > cap")
}
- // Declare slice so that gc can see the base pointer in it.
- var x []unsafe.Pointer
-
- // Reinterpret as *SliceHeader to edit.
- s := (*SliceHeader)(unsafe.Pointer(&x))
- s.Data = uintptr(unsafe_NewArray(typ.Elem().(*rtype), cap))
- s.Len = len
- s.Cap = cap
-
- return Value{typ.common(), unsafe.Pointer(&x), flagIndir | flag(Slice)<<flagKindShift}
+ s := sliceHeader{unsafe_NewArray(typ.Elem().(*rtype), cap), len, cap}
+ return Value{typ.common(), unsafe.Pointer(&s), 0, flagIndir | flag(Slice)<<flagKindShift}
}
// MakeChan creates a new channel with the specified type and buffer size.
panic("reflect.MakeChan: unidirectional channel type")
}
ch := makechan(typ.(*rtype), uint64(buffer))
- return Value{typ.common(), unsafe.Pointer(ch), flag(Chan) << flagKindShift}
+ return Value{typ.common(), ch, 0, flag(Chan) << flagKindShift}
}
// MakeMap creates a new map of the specified type.
panic("reflect.MakeMap of non-map type")
}
m := makemap(typ.(*rtype))
- return Value{typ.common(), unsafe.Pointer(m), flag(Map) << flagKindShift}
+ return Value{typ.common(), m, 0, flag(Map) << flagKindShift}
}
// Indirect returns the value that v points to.
}
// TODO(rsc): Eliminate this terrible hack.
- // In the call to packValue, eface.typ doesn't escape,
- // and eface.word is an integer. So it looks like
- // i (= eface) doesn't escape. But really it does,
- // because eface.word is actually a pointer.
+ // In the call to unpackEface, i.typ doesn't escape,
+ // and i.word is an integer. So it looks like
+ // i doesn't escape. But really it does,
+ // because i.word is actually a pointer.
escapes(i)
- // For an interface value with the noAddr bit set,
- // the representation is identical to an empty interface.
- eface := *(*emptyInterface)(unsafe.Pointer(&i))
- typ := eface.typ
- fl := flag(typ.Kind()) << flagKindShift
- if typ.size > ptrSize {
- fl |= flagIndir
- }
- return Value{typ, unsafe.Pointer(eface.word), fl}
+ return unpackEface(i)
}
// Zero returns a Value representing the zero value for the specified type.
t := typ.common()
fl := flag(t.Kind()) << flagKindShift
if t.size <= ptrSize {
- return Value{t, nil, fl}
+ return Value{t, nil, 0, fl}
}
- return Value{t, unsafe_New(typ.(*rtype)), fl | flagIndir}
+ return Value{t, unsafe_New(typ.(*rtype)), 0, fl | flagIndir}
}
// New returns a Value representing a pointer to a new zero value
}
ptr := unsafe_New(typ.(*rtype))
fl := flag(Ptr) << flagKindShift
- return Value{typ.common().ptrTo(), ptr, fl}
+ return Value{typ.common().ptrTo(), ptr, 0, fl}
}
// 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(Ptr) << flagKindShift
- return Value{typ.common().ptrTo(), p, fl}
+ return Value{typ.common().ptrTo(), p, 0, fl}
}
// assignTo returns a value v that can be assigned directly to typ.
v.typ = dst
fl := v.flag & (flagRO | flagAddr | flagIndir)
fl |= flag(dst.Kind()) << flagKindShift
- return Value{dst, v.val, fl}
+ return Value{dst, v.ptr, v.scalar, fl}
case implements(dst, v.typ):
if target == nil {
} else {
ifaceE2I(dst, x, unsafe.Pointer(target))
}
- return Value{dst, unsafe.Pointer(target), flagIndir | flag(Interface)<<flagKindShift}
+ return Value{dst, unsafe.Pointer(target), 0, flagIndir | flag(Interface)<<flagKindShift}
}
// Failed.
// Assume ptrSize >= 4, so this must be uint64.
ptr := unsafe_New(typ)
*(*uint64)(unsafe.Pointer(ptr)) = bits
- return Value{typ, ptr, f | flagIndir | flag(typ.Kind())<<flagKindShift}
+ return Value{typ, ptr, 0, f | flagIndir | flag(typ.Kind())<<flagKindShift}
}
- var w iword
+ var s uintptr
switch typ.size {
case 1:
- *(*uint8)(unsafe.Pointer(&w)) = uint8(bits)
+ *(*uint8)(unsafe.Pointer(&s)) = uint8(bits)
case 2:
- *(*uint16)(unsafe.Pointer(&w)) = uint16(bits)
+ *(*uint16)(unsafe.Pointer(&s)) = uint16(bits)
case 4:
- *(*uint32)(unsafe.Pointer(&w)) = uint32(bits)
+ *(*uint32)(unsafe.Pointer(&s)) = uint32(bits)
case 8:
- *(*uint64)(unsafe.Pointer(&w)) = uint64(bits)
+ *(*uint64)(unsafe.Pointer(&s)) = uint64(bits)
}
- return Value{typ, unsafe.Pointer(w), f | flag(typ.Kind())<<flagKindShift}
+ return Value{typ, nil, s, f | flag(typ.Kind())<<flagKindShift}
}
// makeFloat returns a Value of type t equal to v (possibly truncated to float32),
// Assume ptrSize >= 4, so this must be float64.
ptr := unsafe_New(typ)
*(*float64)(unsafe.Pointer(ptr)) = v
- return Value{typ, ptr, f | flagIndir | flag(typ.Kind())<<flagKindShift}
+ return Value{typ, ptr, 0, f | flagIndir | flag(typ.Kind())<<flagKindShift}
}
- var w iword
+ var s uintptr
switch typ.size {
case 4:
- *(*float32)(unsafe.Pointer(&w)) = float32(v)
+ *(*float32)(unsafe.Pointer(&s)) = float32(v)
case 8:
- *(*float64)(unsafe.Pointer(&w)) = v
+ *(*float64)(unsafe.Pointer(&s)) = v
}
- return Value{typ, unsafe.Pointer(w), f | flag(typ.Kind())<<flagKindShift}
+ return Value{typ, nil, s, f | flag(typ.Kind())<<flagKindShift}
}
// makeComplex returns a Value of type t equal to v (possibly truncated to complex64),
case 16:
*(*complex128)(unsafe.Pointer(ptr)) = v
}
- return Value{typ, ptr, f | flagIndir | flag(typ.Kind())<<flagKindShift}
+ return Value{typ, ptr, 0, f | flagIndir | flag(typ.Kind())<<flagKindShift}
}
// Assume ptrSize <= 8 so this must be complex64.
- var w iword
- *(*complex64)(unsafe.Pointer(&w)) = complex64(v)
- return Value{typ, unsafe.Pointer(w), f | flag(typ.Kind())<<flagKindShift}
+ var s uintptr
+ *(*complex64)(unsafe.Pointer(&s)) = complex64(v)
+ return Value{typ, nil, s, f | flag(typ.Kind())<<flagKindShift}
}
func makeString(f flag, v string, t Type) Value {
func cvtDirect(v Value, typ Type) Value {
f := v.flag
t := typ.common()
- val := v.val
+ ptr := v.ptr
if f&flagAddr != 0 {
// indirect, mutable word - make a copy
- ptr := unsafe_New(t)
- memmove(ptr, val, t.size)
- val = ptr
+ c := unsafe_New(t)
+ memmove(c, ptr, t.size)
+ ptr = c
f &^= flagAddr
}
- return Value{t, val, v.flag&flagRO | f}
+ return Value{t, ptr, v.scalar, v.flag&flagRO | f} // v.flag&flagRO|f == f?
}
// convertOp: concrete -> interface
} else {
ifaceE2I(typ.(*rtype), x, unsafe.Pointer(target))
}
- return Value{typ.common(), unsafe.Pointer(target), v.flag&flagRO | flagIndir | flag(Interface)<<flagKindShift}
+ return Value{typ.common(), unsafe.Pointer(target), 0, v.flag&flagRO | flagIndir | flag(Interface)<<flagKindShift}
}
// convertOp: interface -> interface
}
// implemented in ../pkg/runtime
-func chancap(ch iword) int
-func chanclose(ch iword)
-func chanlen(ch iword) int
-func chanrecv(t *rtype, ch iword, nb bool) (val iword, selected, received bool)
-func chansend(t *rtype, ch iword, val iword, nb bool) bool
-
-func makechan(typ *rtype, size uint64) (ch iword)
-func makemap(t *rtype) (m iword)
-func mapaccess(t *rtype, m iword, key iword) (val iword, ok bool)
-func mapassign(t *rtype, m iword, key, val iword, ok bool)
-func mapiterinit(t *rtype, m iword) *byte
-func mapiterkey(it *byte) (key iword, ok bool)
-func mapiternext(it *byte)
-func maplen(m iword) int
+func chancap(ch unsafe.Pointer) int
+func chanclose(ch unsafe.Pointer)
+func chanlen(ch unsafe.Pointer) int
+func chanrecv(t *rtype, ch unsafe.Pointer, nb bool) (val iword, selected, received bool)
+func chansend(t *rtype, ch unsafe.Pointer, val iword, nb bool) bool
+
+func makechan(typ *rtype, size uint64) (ch unsafe.Pointer)
+func makemap(t *rtype) (m unsafe.Pointer)
+func mapaccess(t *rtype, m unsafe.Pointer, key unsafe.Pointer) (val unsafe.Pointer)
+func mapassign(t *rtype, m unsafe.Pointer, key, val unsafe.Pointer)
+func mapdelete(t *rtype, m unsafe.Pointer, key unsafe.Pointer)
+func mapiterinit(t *rtype, m unsafe.Pointer) unsafe.Pointer
+func mapiterkey(it unsafe.Pointer) (key unsafe.Pointer)
+func mapiternext(it unsafe.Pointer)
+func maplen(m unsafe.Pointer) int
func call(fn, arg unsafe.Pointer, n uint32)
func ifaceE2I(t *rtype, src interface{}, dst unsafe.Pointer)