diff options
Diffstat (limited to 'libgo/go/reflect/value.go')
| -rw-r--r-- | libgo/go/reflect/value.go | 593 |
1 files changed, 181 insertions, 412 deletions
diff --git a/libgo/go/reflect/value.go b/libgo/go/reflect/value.go index c36e9954427..09210b37b70 100644 --- a/libgo/go/reflect/value.go +++ b/libgo/go/reflect/value.go @@ -7,40 +7,12 @@ package reflect import ( "math" "runtime" - "strconv" "unsafe" ) -const bigEndian = false // can be smarter if we find a big-endian machine const ptrSize = unsafe.Sizeof((*byte)(nil)) const cannotSet = "cannot set value obtained from unexported struct field" -// TODO: This will have to go away when -// the new gc goes in. -func memmove(adst, asrc unsafe.Pointer, n uintptr) { - dst := uintptr(adst) - src := uintptr(asrc) - switch { - case src < dst && src+n > dst: - // byte copy backward - // careful: i is unsigned - for i := n; i > 0; { - i-- - *(*byte)(unsafe.Pointer(dst + i)) = *(*byte)(unsafe.Pointer(src + i)) - } - case (n|src|dst)&(ptrSize-1) != 0: - // byte copy forward - for i := uintptr(0); i < n; i++ { - *(*byte)(unsafe.Pointer(dst + i)) = *(*byte)(unsafe.Pointer(src + i)) - } - default: - // word copy forward - for i := uintptr(0); i < n; i += ptrSize { - *(*uintptr)(unsafe.Pointer(dst + i)) = *(*uintptr)(unsafe.Pointer(src + i)) - } - } -} - // Value is the reflection interface to a Go value. // // Not all methods apply to all kinds of values. Restrictions, @@ -64,16 +36,8 @@ type Value struct { // Pointer-valued data or, if flagIndir is set, pointer to data. // Valid when either flagIndir is set or typ.pointers() is true. - // Gccgo always uses this field. 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. - // Gccgo never uses this field. - // scalar uintptr - // flag holds metadata about the value. // The lowest bits are flag bits: // - flagRO: obtained via unexported field, so read-only @@ -84,7 +48,7 @@ type Value struct { // This repeats typ.Kind() except for method values. // The remaining 23+ bits give a method number for method values. // If flag.kind() != Func, code can assume that flagMethod is unset. - // If typ.size > ptrSize, code can assume that flagIndir is set. + // If ifaceIndir(typ), code can assume that flagIndir is set. flag // A method value represents a curried method invocation @@ -97,19 +61,18 @@ type Value struct { type flag uintptr const ( - flagRO flag = 1 << iota - flagIndir - flagAddr - flagMethod - flagMethodFn // gccgo: first fn parameter is always pointer - flagKindShift = iota flagKindWidth = 5 // there are 27 kinds flagKindMask flag = 1<<flagKindWidth - 1 - flagMethodShift = flagKindShift + flagKindWidth + flagRO flag = 1 << 5 + flagIndir flag = 1 << 6 + flagAddr flag = 1 << 7 + flagMethod flag = 1 << 8 + flagMethodFn flag = 1 << 9 // gccgo: first fn parameter is always pointer + flagMethodShift = 10 ) func (f flag) kind() Kind { - return Kind((f >> flagKindShift) & flagKindMask) + return Kind(f & flagKindMask) } // pointer returns the underlying pointer represented by v. @@ -131,11 +94,11 @@ func packEface(v Value) interface{} { e := (*emptyInterface)(unsafe.Pointer(&i)) // First, fill in the data portion of the interface. switch { - case v.Kind() != Ptr && v.Kind() != UnsafePointer: - // Value is indirect, and so is the interface we're making. + case ifaceIndir(t): if v.flag&flagIndir == 0 { - panic("reflect: missing flagIndir") + panic("bad indir") } + // 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 @@ -144,23 +107,14 @@ func packEface(v Value) interface{} { memmove(c, ptr, t.size) ptr = c } - e.word = iword(ptr) + e.word = 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)) - } + e.word = *(*unsafe.Pointer)(v.ptr) default: // Value is direct, and so is the interface. - if t.pointers() { - e.word = iword(v.ptr) - } else { - // e.word = iword(v.scalar) - panic("reflect: missing flagIndir") - } + e.word = v.ptr } // Now, fill in the type portion. We're very careful here not // to have any operation between the e.word and e.typ assignments @@ -178,8 +132,8 @@ func unpackEface(i interface{}) Value { if t == nil { return Value{} } - f := flag(t.Kind()) << flagKindShift - if t.Kind() != Ptr && t.Kind() != UnsafePointer { + f := flag(t.Kind()) + if ifaceIndir(t) { f |= flagIndir } return Value{t, unsafe.Pointer(e.word), f} @@ -211,78 +165,10 @@ func methodName() string { return f.Name() } -// An iword is the word that would be stored in an -// interface to represent a given value v. Specifically, if v is -// bigger than a pointer, its word is a pointer to v's data. -// Otherwise, its word holds the data stored -// in its leading bytes (so is not a pointer). -// This type is very dangerous for the garbage collector because -// it must be treated conservatively. We try to never expose it -// to the GC here so that GC remains precise. -type iword unsafe.Pointer - -// 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 uintptr - switch n { - default: - panic("reflect: internal error: loadScalar of " + strconv.Itoa(int(n)) + "-byte value") - case 0: - case 1: - *(*uint8)(unsafe.Pointer(&w)) = *(*uint8)(p) - case 2: - *(*uint16)(unsafe.Pointer(&w)) = *(*uint16)(p) - case 3: - *(*[3]byte)(unsafe.Pointer(&w)) = *(*[3]byte)(p) - case 4: - *(*uint32)(unsafe.Pointer(&w)) = *(*uint32)(p) - case 5: - *(*[5]byte)(unsafe.Pointer(&w)) = *(*[5]byte)(p) - case 6: - *(*[6]byte)(unsafe.Pointer(&w)) = *(*[6]byte)(p) - case 7: - *(*[7]byte)(unsafe.Pointer(&w)) = *(*[7]byte)(p) - case 8: - *(*uint64)(unsafe.Pointer(&w)) = *(*uint64)(p) - } - return w -} - -// 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: storeScalar of " + strconv.Itoa(int(n)) + "-byte value") - case 0: - case 1: - *(*uint8)(p) = *(*uint8)(unsafe.Pointer(&w)) - case 2: - *(*uint16)(p) = *(*uint16)(unsafe.Pointer(&w)) - case 3: - *(*[3]byte)(p) = *(*[3]byte)(unsafe.Pointer(&w)) - case 4: - *(*uint32)(p) = *(*uint32)(unsafe.Pointer(&w)) - case 5: - *(*[5]byte)(p) = *(*[5]byte)(unsafe.Pointer(&w)) - case 6: - *(*[6]byte)(p) = *(*[6]byte)(unsafe.Pointer(&w)) - case 7: - *(*[7]byte)(p) = *(*[7]byte)(unsafe.Pointer(&w)) - case 8: - *(*uint64)(p) = *(*uint64)(unsafe.Pointer(&w)) - } -} - // emptyInterface is the header for an interface{} value. type emptyInterface struct { typ *rtype - word iword + word unsafe.Pointer } // nonEmptyInterface is the header for a interface value with methods. @@ -292,7 +178,7 @@ type nonEmptyInterface struct { typ *rtype // dynamic concrete type fun [100000]unsafe.Pointer // method table } - word iword + word unsafe.Pointer } // mustBe panics if f's kind is not expected. @@ -302,9 +188,8 @@ type nonEmptyInterface struct { // v.flag.mustBe(Bool), which will only bother to copy the // single important word for the receiver. func (f flag) mustBe(expected Kind) { - k := f.kind() - if k != expected { - panic(&ValueError{methodName(), k}) + if f.kind() != expected { + panic(&ValueError{methodName(), f.kind()}) } } @@ -344,18 +229,14 @@ func (v Value) Addr() Value { if v.flag&flagAddr == 0 { panic("reflect.Value.Addr of unaddressable value") } - return Value{v.typ.ptrTo(), v.ptr /* 0, */, (v.flag & flagRO) | flag(Ptr)<<flagKindShift} + return Value{v.typ.ptrTo(), v.ptr, (v.flag & flagRO) | flag(Ptr)} } // Bool returns v's underlying value. // It panics if v's kind is not Bool. func (v Value) Bool() bool { v.mustBe(Bool) - if v.flag&flagIndir != 0 { - return *(*bool)(v.ptr) - } - // return *(*bool)(unsafe.Pointer(&v.scalar)) - panic("reflect: missing flagIndir") + return *(*bool)(v.ptr) } // Bytes returns v's underlying value. @@ -594,7 +475,7 @@ func methodReceiver(op string, v Value, methodIndex int) (rcvrtype, t *rtype, fn i := methodIndex if v.typ.Kind() == Interface { tt := (*interfaceType)(unsafe.Pointer(v.typ)) - if i < 0 || i >= len(tt.methods) { + if uint(i) >= uint(len(tt.methods)) { panic("reflect: internal error: invalid method index") } m := &tt.methods[i] @@ -611,7 +492,7 @@ func methodReceiver(op string, v Value, methodIndex int) (rcvrtype, t *rtype, fn } else { rcvrtype = v.typ ut := v.typ.uncommon() - if ut == nil || i < 0 || i >= len(ut.methods) { + if ut == nil || uint(i) >= uint(len(ut.methods)) { panic("reflect: internal error: invalid method index") } m := &ut.methods[i] @@ -634,19 +515,10 @@ func storeRcvr(v Value, p unsafe.Pointer) { // the interface data word becomes the receiver word iface := (*nonEmptyInterface)(v.ptr) *(*unsafe.Pointer)(p) = unsafe.Pointer(iface.word) - } else if v.flag&flagIndir != 0 { - if t.size > ptrSize { - *(*unsafe.Pointer)(p) = v.ptr - } else if t.pointers() { - *(*unsafe.Pointer)(p) = *(*unsafe.Pointer)(v.ptr) - } else { - *(*uintptr)(p) = loadScalar(v.ptr, t.size) - } - } else if t.pointers() { - *(*unsafe.Pointer)(p) = v.ptr + } else if v.flag&flagIndir != 0 && !ifaceIndir(t) { + *(*unsafe.Pointer)(p) = *(*unsafe.Pointer)(v.ptr) } else { - // *(*uintptr)(p) = v.scalar - panic("reflect: missing flagIndir") + *(*unsafe.Pointer)(p) = v.ptr } } @@ -679,7 +551,7 @@ func (v Value) Cap() int { // Slice is always bigger than a word; assume flagIndir. return (*sliceHeader)(v.ptr).Cap } - panic(&ValueError{"reflect.Value.Cap", k}) + panic(&ValueError{"reflect.Value.Cap", v.kind()}) } // Close closes the channel v. @@ -696,16 +568,11 @@ func (v Value) Complex() complex128 { k := v.kind() switch k { case Complex64: - if v.flag&flagIndir != 0 { - return complex128(*(*complex64)(v.ptr)) - } - // return complex128(*(*complex64)(unsafe.Pointer(&v.scalar))) - panic("reflect: missing flagIndir") + return complex128(*(*complex64)(v.ptr)) case Complex128: - // complex128 is always bigger than a word; assume flagIndir. return *(*complex128)(v.ptr) } - panic(&ValueError{"reflect.Value.Complex", k}) + panic(&ValueError{"reflect.Value.Complex", v.kind()}) } // Elem returns the value that the interface v contains @@ -725,7 +592,9 @@ func (v Value) Elem() Value { })(v.ptr)) } x := unpackEface(eface) - x.flag |= v.flag & flagRO + if x.flag != 0 { + x.flag |= v.flag & flagRO + } return x case Ptr: ptr := v.ptr @@ -739,58 +608,46 @@ func (v Value) Elem() Value { tt := (*ptrType)(unsafe.Pointer(v.typ)) typ := tt.elem fl := v.flag&flagRO | flagIndir | flagAddr - fl |= flag(typ.Kind() << flagKindShift) - return Value{typ, ptr /* 0, */, fl} + fl |= flag(typ.Kind()) + return Value{typ, ptr, fl} } - panic(&ValueError{"reflect.Value.Elem", k}) + panic(&ValueError{"reflect.Value.Elem", v.kind()}) } // Field returns the i'th field of the struct v. // It panics if v's Kind is not Struct or i is out of range. func (v Value) Field(i int) Value { - v.mustBe(Struct) + if v.kind() != Struct { + panic(&ValueError{"reflect.Value.Field", v.kind()}) + } tt := (*structType)(unsafe.Pointer(v.typ)) - if i < 0 || i >= len(tt.fields) { + if uint(i) >= uint(len(tt.fields)) { panic("reflect: Field index out of range") } field := &tt.fields[i] typ := field.typ // Inherit permission bits from v. - fl := v.flag & (flagRO | flagIndir | flagAddr) + fl := v.flag&(flagRO|flagIndir|flagAddr) | flag(typ.Kind()) // Using an unexported field forces flagRO. if field.pkgPath != nil { fl |= flagRO } - fl |= flag(typ.Kind()) << flagKindShift - - var ptr unsafe.Pointer - // var scalar uintptr - switch { - case fl&flagIndir != 0: - // Indirect. Just bump pointer. - 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: - // Must be scalar. Discard leading bytes. - // scalar = v.scalar << (field.offset * 8) - panic("reflect: missing flagIndir") - default: - // Must be scalar. Discard leading bytes. - // scalar = v.scalar >> (field.offset * 8) - panic("reflect: missing flagIndir") - } - - return Value{typ, ptr /* scalar, */, fl} + // 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, + // so v.ptr + field.offset is still okay. + ptr := unsafe.Pointer(uintptr(v.ptr) + field.offset) + return Value{typ, ptr, fl} } // FieldByIndex returns the nested field corresponding to index. // It panics if v's Kind is not struct. func (v Value) FieldByIndex(index []int) Value { + if len(index) == 1 { + return v.Field(index[0]) + } v.mustBe(Struct) for i, x := range index { if i > 0 { @@ -822,7 +679,6 @@ func (v Value) FieldByName(name string) Value { // It panics if v's Kind is not struct. // It returns the zero Value if no field was found. func (v Value) FieldByNameFunc(match func(string) bool) Value { - v.mustBe(Struct) if f, ok := v.typ.FieldByNameFunc(match); ok { return v.FieldByIndex(f.Index) } @@ -835,19 +691,11 @@ func (v Value) Float() float64 { k := v.kind() switch k { case Float32: - if v.flag&flagIndir != 0 { - return float64(*(*float32)(v.ptr)) - } - // return float64(*(*float32)(unsafe.Pointer(&v.scalar))) - panic("reflect: missing flagIndir") + return float64(*(*float32)(v.ptr)) case Float64: - if v.flag&flagIndir != 0 { - return *(*float64)(v.ptr) - } - // return *(*float64)(unsafe.Pointer(&v.scalar)) - panic("reflect: missing flagIndir") + return *(*float64)(v.ptr) } - panic(&ValueError{"reflect.Value.Float", k}) + panic(&ValueError{"reflect.Value.Float", v.kind()}) } var uint8Type = TypeOf(uint8(0)).(*rtype) @@ -855,82 +703,54 @@ var uint8Type = TypeOf(uint8(0)).(*rtype) // 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 { - k := v.kind() - switch k { + switch v.kind() { case Array: tt := (*arrayType)(unsafe.Pointer(v.typ)) - if i < 0 || i > int(tt.len) { + if uint(i) >= uint(tt.len) { panic("reflect: array index out of range") } typ := tt.elem - fl := v.flag & (flagRO | flagIndir | flagAddr) // bits same as overall array - fl |= flag(typ.Kind()) << flagKindShift offset := uintptr(i) * typ.size - var val unsafe.Pointer - switch { - case fl&flagIndir != 0: - // Indirect. Just bump pointer. - 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. - // scalar = v.scalar << (offset * 8) - panic("reflect: missing flagIndir") - default: - // Direct. Discard leading bytes. - // scalar = v.scalar >> (offset * 8) - panic("reflect: missing flagIndir") - } - return Value{typ, val /* scalar, */, fl} + // Either flagIndir is set and v.ptr points at array, + // or flagIndir is not set and v.ptr is the actual array data. + // In the former case, we want v.ptr + offset. + // In the latter case, we must be doing Index(0), so offset = 0, + // so v.ptr + offset is still okay. + val := unsafe.Pointer(uintptr(v.ptr) + offset) + fl := v.flag&(flagRO|flagIndir|flagAddr) | flag(typ.Kind()) // bits same as overall array + return Value{typ, val, fl} case Slice: // Element flag same as Elem of Ptr. // Addressable, indirect, possibly read-only. - fl := flagAddr | flagIndir | v.flag&flagRO s := (*sliceHeader)(v.ptr) - if i < 0 || i >= s.Len { + if uint(i) >= uint(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(uintptr(s.Data) + uintptr(i)*typ.size) - return Value{typ, val /* 0, */, fl} + fl := flagAddr | flagIndir | v.flag&flagRO | flag(typ.Kind()) + return Value{typ, val, fl} case String: - fl := v.flag&flagRO | flag(Uint8<<flagKindShift) | flagIndir - s := (*StringHeader)(v.ptr) - if i < 0 || i >= s.Len { + s := (*stringHeader)(v.ptr) + if uint(i) >= uint(s.Len) { panic("reflect: string index out of range") } - b := uintptr(0) - *(*byte)(unsafe.Pointer(&b)) = *(*byte)(unsafe.Pointer(uintptr(s.Data) + uintptr(i))) - return Value{uint8Type, unsafe.Pointer(&b) /* 0, */, fl | flagIndir} + p := unsafe.Pointer(uintptr(s.Data) + uintptr(i)) + fl := v.flag&flagRO | flag(Uint8) | flagIndir + return Value{uint8Type, p, fl} } - panic(&ValueError{"reflect.Value.Index", k}) + panic(&ValueError{"reflect.Value.Index", v.kind()}) } // 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() - var p unsafe.Pointer - if v.flag&flagIndir != 0 { - p = v.ptr - } else { - // The escape analysis is good enough that &v.scalar - // does not trigger a heap allocation. - // p = unsafe.Pointer(&v.scalar) - switch k { - case Int, Int8, Int16, Int32, Int64: - panic("reflect: missing flagIndir") - } - } + p := v.ptr switch k { case Int: return int64(*(*int)(p)) @@ -943,7 +763,7 @@ func (v Value) Int() int64 { case Int64: return int64(*(*int64)(p)) } - panic(&ValueError{"reflect.Value.Int", k}) + panic(&ValueError{"reflect.Value.Int", v.kind()}) } // CanInterface returns true if Interface can be used without panicking. @@ -1040,7 +860,7 @@ func (v Value) IsNil() bool { // Both are always bigger than a word; assume flagIndir. return *(*unsafe.Pointer)(v.ptr) == nil } - panic(&ValueError{"reflect.Value.IsNil", k}) + panic(&ValueError{"reflect.Value.IsNil", v.kind()}) } // IsValid returns true if v represents a value. @@ -1077,7 +897,7 @@ func (v Value) Len() int { // String is bigger than a word; assume flagIndir. return (*stringHeader)(v.ptr).Len } - panic(&ValueError{"reflect.Value.Len", k}) + panic(&ValueError{"reflect.Value.Len", v.kind()}) } // MapIndex returns the value associated with key in the map v. @@ -1100,11 +920,8 @@ func (v Value) MapIndex(key Value) Value { 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) - panic("reflect: missing flagIndir") + k = unsafe.Pointer(&key.ptr) } e := mapaccess(v.typ, v.pointer(), k) if e == nil { @@ -1112,17 +929,15 @@ func (v Value) MapIndex(key Value) Value { } typ := tt.elem fl := (v.flag | key.flag) & flagRO - fl |= flag(typ.Kind()) << flagKindShift - if typ.Kind() != Ptr && typ.Kind() != UnsafePointer { + fl |= flag(typ.Kind()) + if ifaceIndir(typ) { // 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} + return Value{typ, c, fl | flagIndir} } else { - panic("reflect: can't happen") + return Value{typ, *(*unsafe.Pointer)(e), fl} } } @@ -1135,10 +950,7 @@ func (v Value) MapKeys() []Value { tt := (*mapType)(unsafe.Pointer(v.typ)) keyType := tt.key - fl := v.flag&flagRO | flag(keyType.Kind())<<flagKindShift - if keyType.Kind() != Ptr && keyType.Kind() != UnsafePointer { - fl |= flagIndir - } + fl := v.flag&flagRO | flag(keyType.Kind()) m := v.pointer() mlen := int(0) @@ -1156,16 +968,14 @@ func (v Value) MapKeys() []Value { // we can do about it. break } - if keyType.Kind() != Ptr && keyType.Kind() != UnsafePointer { + if ifaceIndir(keyType) { // 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} + a[i] = Value{keyType, c, fl | flagIndir} } else { - panic("reflect: can't happen") + a[i] = Value{keyType, *(*unsafe.Pointer)(key), fl} } mapiternext(it) } @@ -1180,16 +990,16 @@ func (v Value) Method(i int) Value { if v.typ == nil { panic(&ValueError{"reflect.Value.Method", Invalid}) } - if v.flag&flagMethod != 0 || i < 0 || i >= v.typ.NumMethod() { + if v.flag&flagMethod != 0 || uint(i) >= uint(v.typ.NumMethod()) { panic("reflect: Method index out of range") } if v.typ.Kind() == Interface && v.IsNil() { panic("reflect: Method on nil interface value") } fl := v.flag & (flagRO | flagIndir) - fl |= flag(Func) << flagKindShift + fl |= flag(Func) fl |= flag(i)<<flagMethodShift | flagMethod - return Value{v.typ, v.ptr /* v.scalar, */, fl} + return Value{v.typ, v.ptr, fl} } // NumMethod returns the number of methods in the value's method set. @@ -1240,7 +1050,7 @@ func (v Value) OverflowComplex(x complex128) bool { case Complex128: return false } - panic(&ValueError{"reflect.Value.OverflowComplex", k}) + panic(&ValueError{"reflect.Value.OverflowComplex", v.kind()}) } // OverflowFloat returns true if the float64 x cannot be represented by v's type. @@ -1253,7 +1063,7 @@ func (v Value) OverflowFloat(x float64) bool { case Float64: return false } - panic(&ValueError{"reflect.Value.OverflowFloat", k}) + panic(&ValueError{"reflect.Value.OverflowFloat", v.kind()}) } func overflowFloat32(x float64) bool { @@ -1273,7 +1083,7 @@ func (v Value) OverflowInt(x int64) bool { trunc := (x << (64 - bitSize)) >> (64 - bitSize) return x != trunc } - panic(&ValueError{"reflect.Value.OverflowInt", k}) + panic(&ValueError{"reflect.Value.OverflowInt", v.kind()}) } // OverflowUint returns true if the uint64 x cannot be represented by v's type. @@ -1286,7 +1096,7 @@ func (v Value) OverflowUint(x uint64) bool { trunc := (x << (64 - bitSize)) >> (64 - bitSize) return x != trunc } - panic(&ValueError{"reflect.Value.OverflowUint", k}) + panic(&ValueError{"reflect.Value.OverflowUint", v.kind()}) } // Pointer returns v's value as a uintptr. @@ -1331,7 +1141,7 @@ func (v Value) Pointer() uintptr { case Slice: return (*SliceHeader)(v.ptr).Data } - panic(&ValueError{"reflect.Value.Pointer", k}) + panic(&ValueError{"reflect.Value.Pointer", v.kind()}) } // Recv receives and returns a value from the channel v. @@ -1353,9 +1163,9 @@ func (v Value) recv(nb bool) (val Value, ok bool) { panic("reflect: recv on send-only channel") } t := tt.elem - val = Value{t, nil /* 0, */, flag(t.Kind()) << flagKindShift} + val = Value{t, nil, flag(t.Kind())} var p unsafe.Pointer - if t.Kind() != Ptr && t.Kind() != UnsafePointer { + if ifaceIndir(t) { p = unsafe_New(t) val.ptr = p val.flag |= flagIndir @@ -1390,11 +1200,8 @@ func (v Value) send(x Value, nb bool) (selected bool) { var p unsafe.Pointer if x.flag&flagIndir != 0 { p = x.ptr - } else if x.typ.pointers() { - p = unsafe.Pointer(&x.ptr) } else { - // p = unsafe.Pointer(&x.scalar) - panic("reflect: missing flagIndir") + p = unsafe.Pointer(&x.ptr) } return chansend(v.typ, v.pointer(), p, nb) } @@ -1412,11 +1219,8 @@ 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) - } else if x.typ.pointers() { - *(*unsafe.Pointer)(v.ptr) = x.ptr } else { - // memmove(v.ptr, unsafe.Pointer(&x.scalar), v.typ.size) - panic("reflect: missing flagIndir") + *(*unsafe.Pointer)(v.ptr) = x.ptr } } @@ -1456,7 +1260,7 @@ func (v Value) SetComplex(x complex128) { v.mustBeAssignable() switch k := v.kind(); k { default: - panic(&ValueError{"reflect.Value.SetComplex", k}) + panic(&ValueError{"reflect.Value.SetComplex", v.kind()}) case Complex64: *(*complex64)(v.ptr) = complex64(x) case Complex128: @@ -1470,7 +1274,7 @@ func (v Value) SetFloat(x float64) { v.mustBeAssignable() switch k := v.kind(); k { default: - panic(&ValueError{"reflect.Value.SetFloat", k}) + panic(&ValueError{"reflect.Value.SetFloat", v.kind()}) case Float32: *(*float32)(v.ptr) = float32(x) case Float64: @@ -1484,7 +1288,7 @@ func (v Value) SetInt(x int64) { v.mustBeAssignable() switch k := v.kind(); k { default: - panic(&ValueError{"reflect.Value.SetInt", k}) + panic(&ValueError{"reflect.Value.SetInt", v.kind()}) case Int: *(*int)(v.ptr) = int(x) case Int8: @@ -1505,7 +1309,7 @@ func (v Value) SetLen(n int) { v.mustBeAssignable() v.mustBe(Slice) s := (*sliceHeader)(v.ptr) - if n < 0 || n > int(s.Cap) { + if uint(n) > uint(s.Cap) { panic("reflect: slice length out of range in SetLen") } s.Len = n @@ -1539,11 +1343,8 @@ func (v Value) SetMapIndex(key, val Value) { 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) - panic("reflect: missing flagIndir") + k = unsafe.Pointer(&key.ptr) } if val.typ == nil { mapdelete(v.typ, v.pointer(), k) @@ -1554,11 +1355,8 @@ func (v Value) SetMapIndex(key, val Value) { 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) - panic("reflect: missing flagIndir") + e = unsafe.Pointer(&val.ptr) } mapassign(v.typ, v.pointer(), k, e) } @@ -1569,7 +1367,7 @@ func (v Value) SetUint(x uint64) { v.mustBeAssignable() switch k := v.kind(); k { default: - panic(&ValueError{"reflect.Value.SetUint", k}) + panic(&ValueError{"reflect.Value.SetUint", v.kind()}) case Uint: *(*uint)(v.ptr) = uint(x) case Uint8: @@ -1612,7 +1410,7 @@ func (v Value) Slice(i, j int) Value { ) switch kind := v.kind(); kind { default: - panic(&ValueError{"reflect.Value.Slice", kind}) + panic(&ValueError{"reflect.Value.Slice", v.kind()}) case Array: if v.flag&flagAddr == 0 { @@ -1635,7 +1433,7 @@ func (v Value) Slice(i, j int) Value { panic("reflect.Value.Slice: string slice index out of bounds") } t := stringHeader{unsafe.Pointer(uintptr(s.Data) + uintptr(i)), j - i} - return Value{v.typ, unsafe.Pointer(&t) /* 0, */, v.flag} + return Value{v.typ, unsafe.Pointer(&t), v.flag} } if i < 0 || j < i || j > cap { @@ -1647,12 +1445,17 @@ func (v Value) Slice(i, j int) Value { // 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 + if cap-i > 0 { + s.Data = unsafe.Pointer(uintptr(base) + uintptr(i)*typ.elem.Size()) + } else { + // do not advance pointer, to avoid pointing beyond end of slice + s.Data = base + } - fl := v.flag&flagRO | flagIndir | flag(Slice)<<flagKindShift - return Value{typ.common(), unsafe.Pointer(&x) /* 0, */, fl} + fl := v.flag&flagRO | flagIndir | flag(Slice) + return Value{typ.common(), unsafe.Pointer(&x), fl} } // Slice3 is the 3-index form of the slice operation: it returns v[i:j:k]. @@ -1666,7 +1469,7 @@ func (v Value) Slice3(i, j, k int) Value { ) switch kind := v.kind(); kind { default: - panic(&ValueError{"reflect.Value.Slice3", kind}) + panic(&ValueError{"reflect.Value.Slice3", v.kind()}) case Array: if v.flag&flagAddr == 0 { @@ -1694,12 +1497,17 @@ func (v Value) Slice3(i, j, k int) Value { // 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 + if k-i > 0 { + s.Data = unsafe.Pointer(uintptr(base) + uintptr(i)*typ.elem.Size()) + } else { + // do not advance pointer, to avoid pointing beyond end of slice + s.Data = base + } - fl := v.flag&flagRO | flagIndir | flag(Slice)<<flagKindShift - return Value{typ.common(), unsafe.Pointer(&x) /* 0, */, fl} + fl := v.flag&flagRO | flagIndir | flag(Slice) + return Value{typ.common(), unsafe.Pointer(&x), fl} } // String returns the string v's underlying value, as a string. @@ -1715,7 +1523,7 @@ func (v Value) String() string { } // If you call String on a reflect.Value of other type, it's better to // print something than to panic. Useful in debugging. - return "<" + v.typ.String() + " Value>" + return "<" + v.Type().String() + " Value>" } // TryRecv attempts to receive a value from the channel v but will not block. @@ -1756,7 +1564,7 @@ func (v Value) Type() Type { if v.typ.Kind() == Interface { // Method on interface. tt := (*interfaceType)(unsafe.Pointer(v.typ)) - if i < 0 || i >= len(tt.methods) { + if uint(i) >= uint(len(tt.methods)) { panic("reflect: internal error: invalid method index") } m := &tt.methods[i] @@ -1764,7 +1572,7 @@ func (v Value) Type() Type { } // Method on concrete type. ut := v.typ.uncommon() - if ut == nil || i < 0 || i >= len(ut.methods) { + if ut == nil || uint(i) >= uint(len(ut.methods)) { panic("reflect: internal error: invalid method index") } m := &ut.methods[i] @@ -1775,18 +1583,7 @@ func (v Value) Type() Type { // It panics if v's Kind is not Uint, Uintptr, Uint8, Uint16, Uint32, or Uint64. func (v Value) Uint() uint64 { k := v.kind() - var p unsafe.Pointer - if v.flag&flagIndir != 0 { - p = v.ptr - } else { - // The escape analysis is good enough that &v.scalar - // does not trigger a heap allocation. - // p = unsafe.Pointer(&v.scalar) - switch k { - case Uint, Uint8, Uint16, Uint32, Uint64, Uintptr: - panic("reflect: missing flagIndir") - } - } + p := v.ptr switch k { case Uint: return uint64(*(*uint)(p)) @@ -1801,7 +1598,7 @@ func (v Value) Uint() uint64 { case Uintptr: return uint64(*(*uintptr)(p)) } - panic(&ValueError{"reflect.Value.Uint", k}) + panic(&ValueError{"reflect.Value.Uint", v.kind()}) } // UnsafeAddr returns a pointer to v's data. @@ -1940,17 +1737,6 @@ func Copy(dst, src Value) int { n = sn } - // 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)) - } - return n - } - // Copy via memmove. var da, sa unsafe.Pointer if dk == Array { @@ -1958,7 +1744,9 @@ func Copy(dst, src Value) int { } else { da = (*sliceHeader)(dst.ptr).Data } - if sk == Array { + if src.flag&flagIndir == 0 { + sa = unsafe.Pointer(&src.ptr) + } else if sk == Array { sa = src.ptr } else { sa = (*sliceHeader)(src.ptr).Data @@ -1968,7 +1756,7 @@ func Copy(dst, src Value) int { } // A runtimeSelect is a single case passed to rselect. -// This must match ../runtime/chan.c:/runtimeSelect +// This must match ../runtime/select.go:/runtimeSelect type runtimeSelect struct { dir uintptr // 0, SendDir, or RecvDir typ *rtype // channel type @@ -1986,7 +1774,7 @@ func rselect([]runtimeSelect) (chosen int, recvOK bool) // A SelectDir describes the communication direction of a select case. type SelectDir int -// NOTE: These values must match ../runtime/chan.c:/SelectDir. +// NOTE: These values must match ../runtime/select.go:/selectDir. const ( _ SelectDir = iota @@ -2071,11 +1859,8 @@ func Select(cases []SelectCase) (chosen int, recv Value, recvOK bool) { v = v.assignTo("reflect.Select", tt.elem, nil) if v.flag&flagIndir != 0 { rc.val = v.ptr - } else if v.typ.pointers() { - rc.val = unsafe.Pointer(&v.ptr) } else { - // rc.val = unsafe.Pointer(&v.scalar) - panic("reflect: missing flagIndir") + rc.val = unsafe.Pointer(&v.ptr) } case SelectRecv: @@ -2103,11 +1888,11 @@ func Select(cases []SelectCase) (chosen int, recv Value, recvOK bool) { tt := (*chanType)(unsafe.Pointer(runcases[chosen].typ)) t := tt.elem p := runcases[chosen].val - fl := flag(t.Kind()) << flagKindShift - if t.Kind() != Ptr && t.Kind() != UnsafePointer { - recv = Value{t, p /* 0, */, fl | flagIndir} + fl := flag(t.Kind()) + if ifaceIndir(t) { + recv = Value{t, p, fl | flagIndir} } else { - recv = Value{t, *(*unsafe.Pointer)(p) /* 0, */, fl} + recv = Value{t, *(*unsafe.Pointer)(p), fl} } } return chosen, recv, recvOK @@ -2138,7 +1923,7 @@ func MakeSlice(typ Type, len, cap int) Value { } s := sliceHeader{unsafe_NewArray(typ.Elem().(*rtype), cap), len, cap} - return Value{typ.common(), unsafe.Pointer(&s) /* 0, */, flagIndir | flag(Slice)<<flagKindShift} + return Value{typ.common(), unsafe.Pointer(&s), flagIndir | flag(Slice)} } // MakeChan creates a new channel with the specified type and buffer size. @@ -2153,7 +1938,7 @@ func MakeChan(typ Type, buffer int) Value { panic("reflect.MakeChan: unidirectional channel type") } ch := makechan(typ.(*rtype), uint64(buffer)) - return Value{typ.common(), unsafe.Pointer(&ch) /* 0, */, flagIndir | (flag(Chan) << flagKindShift)} + return Value{typ.common(), unsafe.Pointer(&ch), flag(Chan) | flagIndir} } // MakeMap creates a new map of the specified type. @@ -2162,7 +1947,7 @@ func MakeMap(typ Type) Value { panic("reflect.MakeMap of non-map type") } m := makemap(typ.(*rtype)) - return Value{typ.common(), unsafe.Pointer(&m) /* 0, */, flagIndir | (flag(Map) << flagKindShift)} + return Value{typ.common(), unsafe.Pointer(&m), flag(Map) | flagIndir} } // Indirect returns the value that v points to. @@ -2202,11 +1987,11 @@ func Zero(typ Type) Value { panic("reflect: Zero(nil)") } t := typ.common() - fl := flag(t.Kind()) << flagKindShift - if t.Kind() == Ptr || t.Kind() == UnsafePointer { - return Value{t, nil /* 0, */, fl} + fl := flag(t.Kind()) + if ifaceIndir(t) { + return Value{t, unsafe_New(typ.(*rtype)), fl | flagIndir} } - return Value{t, unsafe_New(typ.(*rtype)) /* 0, */, fl | flagIndir} + return Value{t, nil, fl} } // New returns a Value representing a pointer to a new zero value @@ -2216,15 +2001,15 @@ func New(typ Type) Value { panic("reflect: New(nil)") } ptr := unsafe_New(typ.(*rtype)) - fl := flag(Ptr) << flagKindShift - return Value{typ.common().ptrTo(), ptr /* 0, */, fl} + fl := flag(Ptr) + return Value{typ.common().ptrTo(), ptr, 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 /* 0, */, fl} + fl := flag(Ptr) + return Value{typ.common().ptrTo(), p, fl} } // assignTo returns a value v that can be assigned directly to typ. @@ -2241,8 +2026,8 @@ func (v Value) assignTo(context string, dst *rtype, target unsafe.Pointer) Value // Same memory layout, so no harm done. v.typ = dst fl := v.flag & (flagRO | flagAddr | flagIndir) - fl |= flag(dst.Kind()) << flagKindShift - return Value{dst, v.ptr /* v.scalar, */, fl} + fl |= flag(dst.Kind()) + return Value{dst, v.ptr, fl} case implements(dst, v.typ): if target == nil { @@ -2254,7 +2039,7 @@ func (v Value) assignTo(context string, dst *rtype, target unsafe.Pointer) Value } else { ifaceE2I(dst, x, target) } - return Value{dst, target /* 0, */, flagIndir | flag(Interface)<<flagKindShift} + return Value{dst, target, flagIndir | flag(Interface)} } // Failed. @@ -2362,86 +2147,66 @@ func convertOp(dst, src *rtype) func(Value, Type) Value { // where t is a signed or unsigned int type. func makeInt(f flag, bits uint64, t Type) Value { typ := t.common() - if typ.size > ptrSize { - // Assume ptrSize >= 4, so this must be uint64. - ptr := unsafe_New(typ) - *(*uint64)(unsafe.Pointer(ptr)) = bits - return Value{typ, ptr /* 0, */, f | flagIndir | flag(typ.Kind())<<flagKindShift} - } - var s uintptr + ptr := unsafe_New(typ) switch typ.size { case 1: - *(*uint8)(unsafe.Pointer(&s)) = uint8(bits) + *(*uint8)(unsafe.Pointer(ptr)) = uint8(bits) case 2: - *(*uint16)(unsafe.Pointer(&s)) = uint16(bits) + *(*uint16)(unsafe.Pointer(ptr)) = uint16(bits) case 4: - *(*uint32)(unsafe.Pointer(&s)) = uint32(bits) + *(*uint32)(unsafe.Pointer(ptr)) = uint32(bits) case 8: - *(*uint64)(unsafe.Pointer(&s)) = uint64(bits) + *(*uint64)(unsafe.Pointer(ptr)) = bits } - return Value{typ, unsafe.Pointer(&s) /* 0, */, f | flagIndir | flag(typ.Kind())<<flagKindShift} + return Value{typ, ptr, f | flagIndir | flag(typ.Kind())} } // makeFloat returns a Value of type t equal to v (possibly truncated to float32), // where t is a float32 or float64 type. func makeFloat(f flag, v float64, t Type) Value { typ := t.common() - if typ.size > ptrSize { - // Assume ptrSize >= 4, so this must be float64. - ptr := unsafe_New(typ) - *(*float64)(unsafe.Pointer(ptr)) = v - return Value{typ, ptr /* 0, */, f | flagIndir | flag(typ.Kind())<<flagKindShift} - } - - var s uintptr + ptr := unsafe_New(typ) switch typ.size { case 4: - *(*float32)(unsafe.Pointer(&s)) = float32(v) + *(*float32)(unsafe.Pointer(ptr)) = float32(v) case 8: - *(*float64)(unsafe.Pointer(&s)) = v + *(*float64)(unsafe.Pointer(ptr)) = v } - return Value{typ, unsafe.Pointer(&s) /* 0, */, f | flagIndir | flag(typ.Kind())<<flagKindShift} + return Value{typ, ptr, f | flagIndir | flag(typ.Kind())} } // makeComplex returns a Value of type t equal to v (possibly truncated to complex64), // where t is a complex64 or complex128 type. func makeComplex(f flag, v complex128, t Type) Value { typ := t.common() - if typ.size > ptrSize { - ptr := unsafe_New(typ) - switch typ.size { - case 8: - *(*complex64)(unsafe.Pointer(ptr)) = complex64(v) - case 16: - *(*complex128)(unsafe.Pointer(ptr)) = v - } - return Value{typ, ptr /* 0, */, f | flagIndir | flag(typ.Kind())<<flagKindShift} + ptr := unsafe_New(typ) + switch typ.size { + case 8: + *(*complex64)(unsafe.Pointer(ptr)) = complex64(v) + case 16: + *(*complex128)(unsafe.Pointer(ptr)) = v } - - // Assume ptrSize <= 8 so this must be complex64. - var s uintptr - *(*complex64)(unsafe.Pointer(&s)) = complex64(v) - return Value{typ, unsafe.Pointer(&s) /* 0, */, f | flagIndir | flag(typ.Kind())<<flagKindShift} + return Value{typ, ptr, f | flagIndir | flag(typ.Kind())} } func makeString(f flag, v string, t Type) Value { ret := New(t).Elem() ret.SetString(v) - ret.flag = ret.flag&^flagAddr | f | flagIndir + ret.flag = ret.flag&^flagAddr | f return ret } func makeBytes(f flag, v []byte, t Type) Value { ret := New(t).Elem() ret.SetBytes(v) - ret.flag = ret.flag&^flagAddr | f | flagIndir + ret.flag = ret.flag&^flagAddr | f return ret } func makeRunes(f flag, v []rune, t Type) Value { ret := New(t).Elem() ret.setRunes(v) - ret.flag = ret.flag&^flagAddr | f | flagIndir + ret.flag = ret.flag&^flagAddr | f return ret } @@ -2532,7 +2297,7 @@ func cvtDirect(v Value, typ Type) Value { ptr = c f &^= flagAddr } - return Value{t, ptr /* v.scalar, */, v.flag&flagRO | f} // v.flag&flagRO|f == f? + return Value{t, ptr, v.flag&flagRO | f} // v.flag&flagRO|f == f? } // convertOp: concrete -> interface @@ -2544,7 +2309,7 @@ func cvtT2I(v Value, typ Type) Value { } else { ifaceE2I(typ.(*rtype), x, target) } - return Value{typ.common(), target /* 0, */, v.flag&flagRO | flagIndir | flag(Interface)<<flagKindShift} + return Value{typ.common(), target, v.flag&flagRO | flagIndir | flag(Interface)} } // convertOp: interface -> interface @@ -2557,7 +2322,7 @@ func cvtI2I(v Value, typ Type) Value { return cvtT2I(v.Elem(), typ) } -// implemented in ../pkg/runtime +// implemented in ../runtime func chancap(ch unsafe.Pointer) int func chanclose(ch unsafe.Pointer) func chanlen(ch unsafe.Pointer) int @@ -2577,10 +2342,14 @@ 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(typ *rtype, fnaddr unsafe.Pointer, isInterface bool, isMethod bool, params *unsafe.Pointer, results *unsafe.Pointer) + func ifaceE2I(t *rtype, src interface{}, dst unsafe.Pointer) +//go:noescape +//extern memmove +func memmove(adst, asrc unsafe.Pointer, n uintptr) + // Dummy annotation marking that the value x escapes, // for use in cases where the reflect code is so clever that // the compiler cannot follow. |