// Copyright (c) 2012-2020 Ugorji Nwoke. All rights reserved.
// Use of this source code is governed by a MIT license found in the LICENSE file.
//go:build !safe && !codec.safe && !appengine && go1.9
// +build !safe,!codec.safe,!appengine,go1.9
// minimum of go 1.9 is needed, as that is the minimum for all features and linked functions we need
// - typedmemclr was introduced in go 1.8
// - mapassign_fastXXX was introduced in go 1.9
// etc
package codec
import (
"reflect"
_ "runtime" // needed for go linkname(s)
"sync/atomic"
"time"
"unsafe"
)
// This file has unsafe variants of some helper functions.
// MARKER: See helper_unsafe.go for the usage documentation.
// There are a number of helper_*unsafe*.go files.
//
// - helper_unsafe
// unsafe variants of dependent functions
// - helper_unsafe_compiler_gc (gc)
// unsafe variants of dependent functions which cannot be shared with gollvm or gccgo
// - helper_not_unsafe_not_gc (gccgo/gollvm or safe)
// safe variants of functions in helper_unsafe_compiler_gc
// - helper_not_unsafe (safe)
// safe variants of functions in helper_unsafe
// - helper_unsafe_compiler_not_gc (gccgo, gollvm)
// unsafe variants of functions/variables which non-standard compilers need
//
// This way, we can judiciously use build tags to include the right set of files
// for any compiler, and make it run optimally in unsafe mode.
//
// As of March 2021, we cannot differentiate whether running with gccgo or gollvm
// using a build constraint, as both satisfy 'gccgo' build tag.
// Consequently, we must use the lowest common denominator to support both.
// For reflect.Value code, we decided to do the following:
// - if we know the kind, we can elide conditional checks for
// - SetXXX (Int, Uint, String, Bool, etc)
// - SetLen
//
// We can also optimize
// - IsNil
// MARKER: Some functions here will not be hit during code coverage runs due to optimizations, e.g.
// - rvCopySlice: decode calls it if rvGrowSlice didn't set the new slice into the pointer to the orig slice.
// however, helper_unsafe sets it, so there's no need to call rvCopySlice later
// - rvSlice: same as above
// - rvGetArray4Bytes: only called within kArray for []byte, but that is now handled
// within the fast-path directly
const safeMode = false
// helperUnsafeDirectAssignMapEntry says that we should not copy the pointer in the map
// to another value during mapRange/iteration and mapGet calls, but directly assign it.
//
// The only callers of mapRange/iteration is encode.
// Here, we just walk through the values and encode them
//
// The only caller of mapGet is decode.
// Here, it does a Get if the underlying value is a pointer, and decodes into that.
//
// For both users, we are very careful NOT to modify or keep the pointers around.
// Consequently, it is ok for take advantage of the performance that the map is not modified
// during an iteration and we can just "peek" at the internal value" in the map and use it.
const helperUnsafeDirectAssignMapEntry = true
// MARKER: keep in sync with GO_ROOT/src/reflect/value.go
const (
unsafeFlagStickyRO = 1 << 5
unsafeFlagEmbedRO = 1 << 6
unsafeFlagIndir = 1 << 7
unsafeFlagAddr = 1 << 8
unsafeFlagRO = unsafeFlagStickyRO | unsafeFlagEmbedRO
// unsafeFlagKindMask = (1 << 5) - 1 // 5 bits for 27 kinds (up to 31)
// unsafeTypeKindDirectIface = 1 << 5
)
// transientSizeMax below is used in TransientAddr as the backing storage.
//
// Must be >= 16 as the maximum size is a complex128 (or string on 64-bit machines).
const transientSizeMax = 64
// should struct/array support internal strings and slices?
const transientValueHasStringSlice = false
type unsafeString struct {
Data unsafe.Pointer
Len int
}
type unsafeSlice struct {
Data unsafe.Pointer
Len int
Cap int
}
type unsafeIntf struct {
typ unsafe.Pointer
ptr unsafe.Pointer
}
type unsafeReflectValue struct {
unsafeIntf
flag uintptr
}
// keep in sync with stdlib runtime/type.go
type unsafeRuntimeType struct {
size uintptr
// ... many other fields here
}
// unsafeZeroAddr and unsafeZeroSlice points to a read-only block of memory
// used for setting a zero value for most types or creating a read-only
// zero value for a given type.
var (
unsafeZeroAddr = unsafe.Pointer(&unsafeZeroArr[0])
unsafeZeroSlice = unsafeSlice{unsafeZeroAddr, 0, 0}
)
// We use a scratch memory and an unsafeSlice for transient values:
//
// unsafeSlice is used for standalone strings and slices (outside an array or struct).
// scratch memory is used for other kinds, based on contract below:
// - numbers, bool are always transient
// - structs and arrays are transient iff they have no pointers i.e.
// no string, slice, chan, func, interface, map, etc only numbers and bools.
// - slices and strings are transient (using the unsafeSlice)
type unsafePerTypeElem struct {
arr [transientSizeMax]byte // for bool, number, struct, array kinds
slice unsafeSlice // for string and slice kinds
}
func (x *unsafePerTypeElem) addrFor(k reflect.Kind) unsafe.Pointer {
if k == reflect.String || k == reflect.Slice {
x.slice = unsafeSlice{} // memclr
return unsafe.Pointer(&x.slice)
}
x.arr = [transientSizeMax]byte{} // memclr
return unsafe.Pointer(&x.arr)
}
type perType struct {
elems [2]unsafePerTypeElem
}
type decPerType struct {
perType
}
type encPerType struct{}
// TransientAddrK is used for getting a *transient* value to be decoded into,
// which will right away be used for something else.
//
// See notes in helper.go about "Transient values during decoding"
func (x *perType) TransientAddrK(t reflect.Type, k reflect.Kind) reflect.Value {
return rvZeroAddrTransientAnyK(t, k, x.elems[0].addrFor(k))
}
func (x *perType) TransientAddr2K(t reflect.Type, k reflect.Kind) reflect.Value {
return rvZeroAddrTransientAnyK(t, k, x.elems[1].addrFor(k))
}
func (encPerType) AddressableRO(v reflect.Value) reflect.Value {
return rvAddressableReadonly(v)
}
// stringView returns a view of the []byte as a string.
// In unsafe mode, it doesn't incur allocation and copying caused by conversion.
// In regular safe mode, it is an allocation and copy.
func stringView(v []byte) string {
return *(*string)(unsafe.Pointer(&v))
}
// bytesView returns a view of the string as a []byte.
// In unsafe mode, it doesn't incur allocation and copying caused by conversion.
// In regular safe mode, it is an allocation and copy.
func bytesView(v string) (b []byte) {
sx := (*unsafeString)(unsafe.Pointer(&v))
bx := (*unsafeSlice)(unsafe.Pointer(&b))
bx.Data, bx.Len, bx.Cap = sx.Data, sx.Len, sx.Len
return
}
func byteSliceSameData(v1 []byte, v2 []byte) bool {
return (*unsafeSlice)(unsafe.Pointer(&v1)).Data == (*unsafeSlice)(unsafe.Pointer(&v2)).Data
}
// MARKER: okBytesN functions will copy N bytes into the top slots of the return array.
// These functions expect that the bounds are valid, and have been checked before this is called.
// copy(...) does a number of checks which are unnecessary in this situation when in bounds.
func okBytes3(b []byte) (v [4]byte) {
*(*[3]byte)(unsafe.Pointer(&v[1])) = *((*[3]byte)(((*unsafeSlice)(unsafe.Pointer(&b))).Data))
return
}
func okBytes4(b []byte) [4]byte {
return *((*[4]byte)(((*unsafeSlice)(unsafe.Pointer(&b))).Data))
}
func okBytes8(b []byte) [8]byte {
return *((*[8]byte)(((*unsafeSlice)(unsafe.Pointer(&b))).Data))
}
// isNil says whether the value v is nil.
// This applies to references like map/ptr/unsafepointer/chan/func,
// and non-reference values like interface/slice.
func isNil(v interface{}) (rv reflect.Value, isnil bool) {
var ui = (*unsafeIntf)(unsafe.Pointer(&v))
isnil = ui.ptr == nil
if !isnil {
rv, isnil = unsafeIsNilIntfOrSlice(ui, v)
}
return
}
func unsafeIsNilIntfOrSlice(ui *unsafeIntf, v interface{}) (rv reflect.Value, isnil bool) {
rv = reflect.ValueOf(v) // reflect.ValueOf is currently not inline'able - so call it directly
tk := rv.Kind()
isnil = (tk == reflect.Interface || tk == reflect.Slice) && *(*unsafe.Pointer)(ui.ptr) == nil
return
}
// return the pointer for a reference (map/chan/func/pointer/unsafe.Pointer).
// true references (map, func, chan, ptr - NOT slice) may be double-referenced? as flagIndir
//
// Assumes that v is a reference (map/func/chan/ptr/func)
func rvRefPtr(v *unsafeReflectValue) unsafe.Pointer {
if v.flag&unsafeFlagIndir != 0 {
return *(*unsafe.Pointer)(v.ptr)
}
return v.ptr
}
func eq4i(i0, i1 interface{}) bool {
v0 := (*unsafeIntf)(unsafe.Pointer(&i0))
v1 := (*unsafeIntf)(unsafe.Pointer(&i1))
return v0.typ == v1.typ && v0.ptr == v1.ptr
}
func rv4iptr(i interface{}) (v reflect.Value) {
// Main advantage here is that it is inlined, nothing escapes to heap, i is never nil
uv := (*unsafeReflectValue)(unsafe.Pointer(&v))
uv.unsafeIntf = *(*unsafeIntf)(unsafe.Pointer(&i))
uv.flag = uintptr(rkindPtr)
return
}
func rv4istr(i interface{}) (v reflect.Value) {
// Main advantage here is that it is inlined, nothing escapes to heap, i is never nil
uv := (*unsafeReflectValue)(unsafe.Pointer(&v))
uv.unsafeIntf = *(*unsafeIntf)(unsafe.Pointer(&i))
uv.flag = uintptr(rkindString) | unsafeFlagIndir
return
}
func rv2i(rv reflect.Value) (i interface{}) {
// We tap into implememtation details from
// the source go stdlib reflect/value.go, and trims the implementation.
//
// e.g.
// - a map/ptr is a reference, thus flagIndir is not set on it
// - an int/slice is not a reference, thus flagIndir is set on it
urv := (*unsafeReflectValue)(unsafe.Pointer(&rv))
if refBitset.isset(byte(rv.Kind())) && urv.flag&unsafeFlagIndir != 0 {
urv.ptr = *(*unsafe.Pointer)(urv.ptr)
}
return *(*interface{})(unsafe.Pointer(&urv.unsafeIntf))
}
func rvAddr(rv reflect.Value, ptrType reflect.Type) reflect.Value {
urv := (*unsafeReflectValue)(unsafe.Pointer(&rv))
urv.flag = (urv.flag & unsafeFlagRO) | uintptr(reflect.Ptr)
urv.typ = ((*unsafeIntf)(unsafe.Pointer(&ptrType))).ptr
return rv
}
func rvIsNil(rv reflect.Value) bool {
urv := (*unsafeReflectValue)(unsafe.Pointer(&rv))
if urv.flag&unsafeFlagIndir != 0 {
return *(*unsafe.Pointer)(urv.ptr) == nil
}
return urv.ptr == nil
}
func rvSetSliceLen(rv reflect.Value, length int) {
urv := (*unsafeReflectValue)(unsafe.Pointer(&rv))
(*unsafeString)(urv.ptr).Len = length
}
func rvZeroAddrK(t reflect.Type, k reflect.Kind) (rv reflect.Value) {
urv := (*unsafeReflectValue)(unsafe.Pointer(&rv))
urv.typ = ((*unsafeIntf)(unsafe.Pointer(&t))).ptr
urv.flag = uintptr(k) | unsafeFlagIndir | unsafeFlagAddr
urv.ptr = unsafeNew(urv.typ)
return
}
func rvZeroAddrTransientAnyK(t reflect.Type, k reflect.Kind, addr unsafe.Pointer) (rv reflect.Value) {
urv := (*unsafeReflectValue)(unsafe.Pointer(&rv))
urv.typ = ((*unsafeIntf)(unsafe.Pointer(&t))).ptr
urv.flag = uintptr(k) | unsafeFlagIndir | unsafeFlagAddr
urv.ptr = addr
return
}
func rvZeroK(t reflect.Type, k reflect.Kind) (rv reflect.Value) {
urv := (*unsafeReflectValue)(unsafe.Pointer(&rv))
urv.typ = ((*unsafeIntf)(unsafe.Pointer(&t))).ptr
if refBitset.isset(byte(k)) {
urv.flag = uintptr(k)
} else if rtsize2(urv.typ) <= uintptr(len(unsafeZeroArr)) {
urv.flag = uintptr(k) | unsafeFlagIndir
urv.ptr = unsafeZeroAddr
} else { // meaning struct or array
urv.flag = uintptr(k) | unsafeFlagIndir | unsafeFlagAddr
urv.ptr = unsafeNew(urv.typ)
}
return
}
// rvConvert will convert a value to a different type directly,
// ensuring that they still point to the same underlying value.
func rvConvert(v reflect.Value, t reflect.Type) reflect.Value {
uv := (*unsafeReflectValue)(unsafe.Pointer(&v))
uv.typ = ((*unsafeIntf)(unsafe.Pointer(&t))).ptr
return v
}
// rvAddressableReadonly returns an addressable reflect.Value.
//
// Use it within encode calls, when you just want to "read" the underlying ptr
// without modifying the value.
//
// Note that it cannot be used for r/w use, as those non-addressable values
// may have been stored in read-only memory, and trying to write the pointer
// may cause a segfault.
func rvAddressableReadonly(v reflect.Value) reflect.Value {
// hack to make an addressable value out of a non-addressable one.
// Assume folks calling it are passing a value that can be addressable, but isn't.
// This assumes that the flagIndir is already set on it.
// so we just set the flagAddr bit on the flag (and do not set the flagIndir).
uv := (*unsafeReflectValue)(unsafe.Pointer(&v))
uv.flag = uv.flag | unsafeFlagAddr // | unsafeFlagIndir
return v
}
func rtsize2(rt unsafe.Pointer) uintptr {
return ((*unsafeRuntimeType)(rt)).size
}
func rt2id(rt reflect.Type) uintptr {
return uintptr(((*unsafeIntf)(unsafe.Pointer(&rt))).ptr)
}
func i2rtid(i interface{}) uintptr {
return uintptr(((*unsafeIntf)(unsafe.Pointer(&i))).typ)
}
// --------------------------
func unsafeCmpZero(ptr unsafe.Pointer, size int) bool {
var s1 = unsafeString{ptr, size}
var s2 = unsafeString{unsafeZeroAddr, size}
if size > len(unsafeZeroArr) {
arr := make([]byte, size)
s2.Data = unsafe.Pointer(&arr[0])
}
return *(*string)(unsafe.Pointer(&s1)) == *(*string)(unsafe.Pointer(&s2)) // memcmp
}
func isEmptyValue(v reflect.Value, tinfos *TypeInfos, recursive bool) bool {
urv := (*unsafeReflectValue)(unsafe.Pointer(&v))
if urv.flag == 0 {
return true
}
if recursive {
return isEmptyValueFallbackRecur(urv, v, tinfos)
}
return unsafeCmpZero(urv.ptr, int(rtsize2(urv.typ)))
}
func isEmptyValueFallbackRecur(urv *unsafeReflectValue, v reflect.Value, tinfos *TypeInfos) bool {
const recursive = true
switch v.Kind() {
case reflect.Invalid:
return true
case reflect.String:
return (*unsafeString)(urv.ptr).Len == 0
case reflect.Slice:
return (*unsafeSlice)(urv.ptr).Len == 0
case reflect.Bool:
return !*(*bool)(urv.ptr)
case reflect.Int:
return *(*int)(urv.ptr) == 0
case reflect.Int8:
return *(*int8)(urv.ptr) == 0
case reflect.Int16:
return *(*int16)(urv.ptr) == 0
case reflect.Int32:
return *(*int32)(urv.ptr) == 0
case reflect.Int64:
return *(*int64)(urv.ptr) == 0
case reflect.Uint:
return *(*uint)(urv.ptr) == 0
case reflect.Uint8:
return *(*uint8)(urv.ptr) == 0
case reflect.Uint16:
return *(*uint16)(urv.ptr) == 0
case reflect.Uint32:
return *(*uint32)(urv.ptr) == 0
case reflect.Uint64:
return *(*uint64)(urv.ptr) == 0
case reflect.Uintptr:
return *(*uintptr)(urv.ptr) == 0
case reflect.Float32:
return *(*float32)(urv.ptr) == 0
case reflect.Float64:
return *(*float64)(urv.ptr) == 0
case reflect.Complex64:
return unsafeCmpZero(urv.ptr, 8)
case reflect.Complex128:
return unsafeCmpZero(urv.ptr, 16)
case reflect.Struct:
// return isEmptyStruct(v, tinfos, recursive)
if tinfos == nil {
tinfos = defTypeInfos
}
ti := tinfos.find(uintptr(urv.typ))
if ti == nil {
ti = tinfos.load(rvType(v))
}
return unsafeCmpZero(urv.ptr, int(ti.size))
case reflect.Interface, reflect.Ptr:
// isnil := urv.ptr == nil // (not sufficient, as a pointer value encodes the type)
isnil := urv.ptr == nil || *(*unsafe.Pointer)(urv.ptr) == nil
if recursive && !isnil {
return isEmptyValue(v.Elem(), tinfos, recursive)
}
return isnil
case reflect.UnsafePointer:
return urv.ptr == nil || *(*unsafe.Pointer)(urv.ptr) == nil
case reflect.Chan:
return urv.ptr == nil || len_chan(rvRefPtr(urv)) == 0
case reflect.Map:
return urv.ptr == nil || len_map(rvRefPtr(urv)) == 0
case reflect.Array:
return v.Len() == 0
}
return false
}
// --------------------------
type structFieldInfos struct {
c unsafe.Pointer // source
s unsafe.Pointer // sorted
length int
}
func (x *structFieldInfos) load(source, sorted []*structFieldInfo) {
s := (*unsafeSlice)(unsafe.Pointer(&sorted))
x.s = s.Data
x.length = s.Len
s = (*unsafeSlice)(unsafe.Pointer(&source))
x.c = s.Data
}
func (x *structFieldInfos) sorted() (v []*structFieldInfo) {
*(*unsafeSlice)(unsafe.Pointer(&v)) = unsafeSlice{x.s, x.length, x.length}
// s := (*unsafeSlice)(unsafe.Pointer(&v))
// s.Data = x.sorted0
// s.Len = x.length
// s.Cap = s.Len
return
}
func (x *structFieldInfos) source() (v []*structFieldInfo) {
*(*unsafeSlice)(unsafe.Pointer(&v)) = unsafeSlice{x.c, x.length, x.length}
return
}
// atomicXXX is expected to be 2 words (for symmetry with atomic.Value)
//
// Note that we do not atomically load/store length and data pointer separately,
// as this could lead to some races. Instead, we atomically load/store cappedSlice.
//
// Note: with atomic.(Load|Store)Pointer, we MUST work with an unsafe.Pointer directly.
// ----------------------
type atomicTypeInfoSlice struct {
v unsafe.Pointer // *[]rtid2ti
}
func (x *atomicTypeInfoSlice) load() (s []rtid2ti) {
x2 := atomic.LoadPointer(&x.v)
if x2 != nil {
s = *(*[]rtid2ti)(x2)
}
return
}
func (x *atomicTypeInfoSlice) store(p []rtid2ti) {
atomic.StorePointer(&x.v, unsafe.Pointer(&p))
}
// MARKER: in safe mode, atomicXXX are atomic.Value, which contains an interface{}.
// This is 2 words.
// consider padding atomicXXX here with a uintptr, so they fit into 2 words also.
// --------------------------
type atomicRtidFnSlice struct {
v unsafe.Pointer // *[]codecRtidFn
}
func (x *atomicRtidFnSlice) load() (s []codecRtidFn) {
x2 := atomic.LoadPointer(&x.v)
if x2 != nil {
s = *(*[]codecRtidFn)(x2)
}
return
}
func (x *atomicRtidFnSlice) store(p []codecRtidFn) {
atomic.StorePointer(&x.v, unsafe.Pointer(&p))
}
// --------------------------
type atomicClsErr struct {
v unsafe.Pointer // *clsErr
}
func (x *atomicClsErr) load() (e clsErr) {
x2 := (*clsErr)(atomic.LoadPointer(&x.v))
if x2 != nil {
e = *x2
}
return
}
func (x *atomicClsErr) store(p clsErr) {
atomic.StorePointer(&x.v, unsafe.Pointer(&p))
}
// --------------------------
// to create a reflect.Value for each member field of fauxUnion,
// we first create a global fauxUnion, and create reflect.Value
// for them all.
// This way, we have the flags and type in the reflect.Value.
// Then, when a reflect.Value is called, we just copy it,
// update the ptr to the fauxUnion's, and return it.
type unsafeDecNakedWrapper struct {
fauxUnion
ru, ri, rf, rl, rs, rb, rt reflect.Value // mapping to the primitives above
}
func (n *unsafeDecNakedWrapper) init() {
n.ru = rv4iptr(&n.u).Elem()
n.ri = rv4iptr(&n.i).Elem()
n.rf = rv4iptr(&n.f).Elem()
n.rl = rv4iptr(&n.l).Elem()
n.rs = rv4iptr(&n.s).Elem()
n.rt = rv4iptr(&n.t).Elem()
n.rb = rv4iptr(&n.b).Elem()
// n.rr[] = reflect.ValueOf(&n.)
}
var defUnsafeDecNakedWrapper unsafeDecNakedWrapper
func init() {
defUnsafeDecNakedWrapper.init()
}
func (n *fauxUnion) ru() (v reflect.Value) {
v = defUnsafeDecNakedWrapper.ru
((*unsafeReflectValue)(unsafe.Pointer(&v))).ptr = unsafe.Pointer(&n.u)
return
}
func (n *fauxUnion) ri() (v reflect.Value) {
v = defUnsafeDecNakedWrapper.ri
((*unsafeReflectValue)(unsafe.Pointer(&v))).ptr = unsafe.Pointer(&n.i)
return
}
func (n *fauxUnion) rf() (v reflect.Value) {
v = defUnsafeDecNakedWrapper.rf
((*unsafeReflectValue)(unsafe.Pointer(&v))).ptr = unsafe.Pointer(&n.f)
return
}
func (n *fauxUnion) rl() (v reflect.Value) {
v = defUnsafeDecNakedWrapper.rl
((*unsafeReflectValue)(unsafe.Pointer(&v))).ptr = unsafe.Pointer(&n.l)
return
}
func (n *fauxUnion) rs() (v reflect.Value) {
v = defUnsafeDecNakedWrapper.rs
((*unsafeReflectValue)(unsafe.Pointer(&v))).ptr = unsafe.Pointer(&n.s)
return
}
func (n *fauxUnion) rt() (v reflect.Value) {
v = defUnsafeDecNakedWrapper.rt
((*unsafeReflectValue)(unsafe.Pointer(&v))).ptr = unsafe.Pointer(&n.t)
return
}
func (n *fauxUnion) rb() (v reflect.Value) {
v = defUnsafeDecNakedWrapper.rb
((*unsafeReflectValue)(unsafe.Pointer(&v))).ptr = unsafe.Pointer(&n.b)
return
}
// --------------------------
func rvSetBytes(rv reflect.Value, v []byte) {
urv := (*unsafeReflectValue)(unsafe.Pointer(&rv))
*(*[]byte)(urv.ptr) = v
}
func rvSetString(rv reflect.Value, v string) {
urv := (*unsafeReflectValue)(unsafe.Pointer(&rv))
*(*string)(urv.ptr) = v
}
func rvSetBool(rv reflect.Value, v bool) {
urv := (*unsafeReflectValue)(unsafe.Pointer(&rv))
*(*bool)(urv.ptr) = v
}
func rvSetTime(rv reflect.Value, v time.Time) {
urv := (*unsafeReflectValue)(unsafe.Pointer(&rv))
*(*time.Time)(urv.ptr) = v
}
func rvSetFloat32(rv reflect.Value, v float32) {
urv := (*unsafeReflectValue)(unsafe.Pointer(&rv))
*(*float32)(urv.ptr) = v
}
func rvSetFloat64(rv reflect.Value, v float64) {
urv := (*unsafeReflectValue)(unsafe.Pointer(&rv))
*(*float64)(urv.ptr) = v
}
func rvSetComplex64(rv reflect.Value, v complex64) {
urv := (*unsafeReflectValue)(unsafe.Pointer(&rv))
*(*complex64)(urv.ptr) = v
}
func rvSetComplex128(rv reflect.Value, v complex128) {
urv := (*unsafeReflectValue)(unsafe.Pointer(&rv))
*(*complex128)(urv.ptr) = v
}
func rvSetInt(rv reflect.Value, v int) {
urv := (*unsafeReflectValue)(unsafe.Pointer(&rv))
*(*int)(urv.ptr) = v
}
func rvSetInt8(rv reflect.Value, v int8) {
urv := (*unsafeReflectValue)(unsafe.Pointer(&rv))
*(*int8)(urv.ptr) = v
}
func rvSetInt16(rv reflect.Value, v int16) {
urv := (*unsafeReflectValue)(unsafe.Pointer(&rv))
*(*int16)(urv.ptr) = v
}
func rvSetInt32(rv reflect.Value, v int32) {
urv := (*unsafeReflectValue)(unsafe.Pointer(&rv))
*(*int32)(urv.ptr) = v
}
func rvSetInt64(rv reflect.Value, v int64) {
urv := (*unsafeReflectValue)(unsafe.Pointer(&rv))
*(*int64)(urv.ptr) = v
}
func rvSetUint(rv reflect.Value, v uint) {
urv := (*unsafeReflectValue)(unsafe.Pointer(&rv))
*(*uint)(urv.ptr) = v
}
func rvSetUintptr(rv reflect.Value, v uintptr) {
urv := (*unsafeReflectValue)(unsafe.Pointer(&rv))
*(*uintptr)(urv.ptr) = v
}
func rvSetUint8(rv reflect.Value, v uint8) {
urv := (*unsafeReflectValue)(unsafe.Pointer(&rv))
*(*uint8)(urv.ptr) = v
}
func rvSetUint16(rv reflect.Value, v uint16) {
urv := (*unsafeReflectValue)(unsafe.Pointer(&rv))
*(*uint16)(urv.ptr) = v
}
func rvSetUint32(rv reflect.Value, v uint32) {
urv := (*unsafeReflectValue)(unsafe.Pointer(&rv))
*(*uint32)(urv.ptr) = v
}
func rvSetUint64(rv reflect.Value, v uint64) {
urv := (*unsafeReflectValue)(unsafe.Pointer(&rv))
*(*uint64)(urv.ptr) = v
}
// ----------------
// rvSetZero is rv.Set(reflect.Zero(rv.Type()) for all kinds (including reflect.Interface).
func rvSetZero(rv reflect.Value) {
rvSetDirectZero(rv)
}
func rvSetIntf(rv reflect.Value, v reflect.Value) {
rv.Set(v)
}
// rvSetDirect is rv.Set for all kinds except reflect.Interface.
//
// Callers MUST not pass a value of kind reflect.Interface, as it may cause unexpected segfaults.
func rvSetDirect(rv reflect.Value, v reflect.Value) {
// MARKER: rv.Set for kind reflect.Interface may do a separate allocation if a scalar value.
// The book-keeping is onerous, so we just do the simple ones where a memmove is sufficient.
urv := (*unsafeReflectValue)(unsafe.Pointer(&rv))
uv := (*unsafeReflectValue)(unsafe.Pointer(&v))
if uv.flag&unsafeFlagIndir == 0 {
*(*unsafe.Pointer)(urv.ptr) = uv.ptr
} else if uv.ptr == unsafeZeroAddr {
if urv.ptr != unsafeZeroAddr {
typedmemclr(urv.typ, urv.ptr)
}
} else {
typedmemmove(urv.typ, urv.ptr, uv.ptr)
}
}
// rvSetDirectZero is rv.Set(reflect.Zero(rv.Type()) for all kinds except reflect.Interface.
func rvSetDirectZero(rv reflect.Value) {
urv := (*unsafeReflectValue)(unsafe.Pointer(&rv))
if urv.ptr != unsafeZeroAddr {
typedmemclr(urv.typ, urv.ptr)
}
}
// rvMakeSlice updates the slice to point to a new array.
// It copies data from old slice to new slice.
// It returns set=true iff it updates it, else it just returns a new slice pointing to a newly made array.
func rvMakeSlice(rv reflect.Value, ti *typeInfo, xlen, xcap int) (_ reflect.Value, set bool) {
urv := (*unsafeReflectValue)(unsafe.Pointer(&rv))
ux := (*unsafeSlice)(urv.ptr)
t := ((*unsafeIntf)(unsafe.Pointer(&ti.elem))).ptr
s := unsafeSlice{newarray(t, xcap), xlen, xcap}
if ux.Len > 0 {
typedslicecopy(t, s, *ux)
}
*ux = s
return rv, true
}
// rvSlice returns a sub-slice of the slice given new lenth,
// without modifying passed in value.
// It is typically called when we know that SetLen(...) cannot be done.
func rvSlice(rv reflect.Value, length int) reflect.Value {
urv := (*unsafeReflectValue)(unsafe.Pointer(&rv))
var x []struct{}
ux := (*unsafeSlice)(unsafe.Pointer(&x))
*ux = *(*unsafeSlice)(urv.ptr)
ux.Len = length
urv.ptr = unsafe.Pointer(ux)
return rv
}
// rcGrowSlice updates the slice to point to a new array with the cap incremented, and len set to the new cap value.
// It copies data from old slice to new slice.
// It returns set=true iff it updates it, else it just returns a new slice pointing to a newly made array.
func rvGrowSlice(rv reflect.Value, ti *typeInfo, cap, incr int) (v reflect.Value, newcap int, set bool) {
urv := (*unsafeReflectValue)(unsafe.Pointer(&rv))
ux := (*unsafeSlice)(urv.ptr)
t := ((*unsafeIntf)(unsafe.Pointer(&ti.elem))).ptr
*ux = unsafeGrowslice(t, *ux, cap, incr)
ux.Len = ux.Cap
return rv, ux.Cap, true
}
// ------------
func rvSliceIndex(rv reflect.Value, i int, ti *typeInfo) (v reflect.Value) {
urv := (*unsafeReflectValue)(unsafe.Pointer(&rv))
uv := (*unsafeReflectValue)(unsafe.Pointer(&v))
uv.ptr = unsafe.Pointer(uintptr(((*unsafeSlice)(urv.ptr)).Data) + uintptr(int(ti.elemsize)*i))
uv.typ = ((*unsafeIntf)(unsafe.Pointer(&ti.elem))).ptr
uv.flag = uintptr(ti.elemkind) | unsafeFlagIndir | unsafeFlagAddr
return
}
func rvSliceZeroCap(t reflect.Type) (v reflect.Value) {
urv := (*unsafeReflectValue)(unsafe.Pointer(&v))
urv.typ = ((*unsafeIntf)(unsafe.Pointer(&t))).ptr
urv.flag = uintptr(reflect.Slice) | unsafeFlagIndir
urv.ptr = unsafe.Pointer(&unsafeZeroSlice)
return
}
func rvLenSlice(rv reflect.Value) int {
urv := (*unsafeReflectValue)(unsafe.Pointer(&rv))
return (*unsafeSlice)(urv.ptr).Len
}
func rvCapSlice(rv reflect.Value) int {
urv := (*unsafeReflectValue)(unsafe.Pointer(&rv))
return (*unsafeSlice)(urv.ptr).Cap
}
func rvArrayIndex(rv reflect.Value, i int, ti *typeInfo) (v reflect.Value) {
urv := (*unsafeReflectValue)(unsafe.Pointer(&rv))
uv := (*unsafeReflectValue)(unsafe.Pointer(&v))
uv.ptr = unsafe.Pointer(uintptr(urv.ptr) + uintptr(int(ti.elemsize)*i))
uv.typ = ((*unsafeIntf)(unsafe.Pointer(&ti.elem))).ptr
uv.flag = uintptr(ti.elemkind) | unsafeFlagIndir | unsafeFlagAddr
return
}
// if scratch is nil, then return a writable view (assuming canAddr=true)
func rvGetArrayBytes(rv reflect.Value, scratch []byte) (bs []byte) {
urv := (*unsafeReflectValue)(unsafe.Pointer(&rv))
bx := (*unsafeSlice)(unsafe.Pointer(&bs))
bx.Data = urv.ptr
bx.Len = rv.Len()
bx.Cap = bx.Len
return
}
func rvGetArray4Slice(rv reflect.Value) (v reflect.Value) {
// It is possible that this slice is based off an array with a larger
// len that we want (where array len == slice cap).
// However, it is ok to create an array type that is a subset of the full
// e.g. full slice is based off a *[16]byte, but we can create a *[4]byte
// off of it. That is ok.
//
// Consequently, we use rvLenSlice, not rvCapSlice.
t := reflectArrayOf(rvLenSlice(rv), rvType(rv).Elem())
// v = rvZeroAddrK(t, reflect.Array)
uv := (*unsafeReflectValue)(unsafe.Pointer(&v))
uv.flag = uintptr(reflect.Array) | unsafeFlagIndir | unsafeFlagAddr
uv.typ = ((*unsafeIntf)(unsafe.Pointer(&t))).ptr
urv := (*unsafeReflectValue)(unsafe.Pointer(&rv))
uv.ptr = *(*unsafe.Pointer)(urv.ptr) // slice rv has a ptr to the slice.
return
}
func rvGetSlice4Array(rv reflect.Value, v interface{}) {
// v is a pointer to a slice to be populated
uv := (*unsafeIntf)(unsafe.Pointer(&v))
urv := (*unsafeReflectValue)(unsafe.Pointer(&rv))
s := (*unsafeSlice)(uv.ptr)
s.Data = urv.ptr
s.Len = rv.Len()
s.Cap = s.Len
}
func rvCopySlice(dest, src reflect.Value, elemType reflect.Type) {
typedslicecopy((*unsafeIntf)(unsafe.Pointer(&elemType)).ptr,
*(*unsafeSlice)((*unsafeReflectValue)(unsafe.Pointer(&dest)).ptr),
*(*unsafeSlice)((*unsafeReflectValue)(unsafe.Pointer(&src)).ptr))
}
// ------------
func rvGetBool(rv reflect.Value) bool {
v := (*unsafeReflectValue)(unsafe.Pointer(&rv))
return *(*bool)(v.ptr)
}
func rvGetBytes(rv reflect.Value) []byte {
v := (*unsafeReflectValue)(unsafe.Pointer(&rv))
return *(*[]byte)(v.ptr)
}
func rvGetTime(rv reflect.Value) time.Time {
v := (*unsafeReflectValue)(unsafe.Pointer(&rv))
return *(*time.Time)(v.ptr)
}
func rvGetString(rv reflect.Value) string {
v := (*unsafeReflectValue)(unsafe.Pointer(&rv))
return *(*string)(v.ptr)
}
func rvGetFloat64(rv reflect.Value) float64 {
v := (*unsafeReflectValue)(unsafe.Pointer(&rv))
return *(*float64)(v.ptr)
}
func rvGetFloat32(rv reflect.Value) float32 {
v := (*unsafeReflectValue)(unsafe.Pointer(&rv))
return *(*float32)(v.ptr)
}
func rvGetComplex64(rv reflect.Value) complex64 {
v := (*unsafeReflectValue)(unsafe.Pointer(&rv))
return *(*complex64)(v.ptr)
}
func rvGetComplex128(rv reflect.Value) complex128 {
v := (*unsafeReflectValue)(unsafe.Pointer(&rv))
return *(*complex128)(v.ptr)
}
func rvGetInt(rv reflect.Value) int {
v := (*unsafeReflectValue)(unsafe.Pointer(&rv))
return *(*int)(v.ptr)
}
func rvGetInt8(rv reflect.Value) int8 {
v := (*unsafeReflectValue)(unsafe.Pointer(&rv))
return *(*int8)(v.ptr)
}
func rvGetInt16(rv reflect.Value) int16 {
v := (*unsafeReflectValue)(unsafe.Pointer(&rv))
return *(*int16)(v.ptr)
}
func rvGetInt32(rv reflect.Value) int32 {
v := (*unsafeReflectValue)(unsafe.Pointer(&rv))
return *(*int32)(v.ptr)
}
func rvGetInt64(rv reflect.Value) int64 {
v := (*unsafeReflectValue)(unsafe.Pointer(&rv))
return *(*int64)(v.ptr)
}
func rvGetUint(rv reflect.Value) uint {
v := (*unsafeReflectValue)(unsafe.Pointer(&rv))
return *(*uint)(v.ptr)
}
func rvGetUint8(rv reflect.Value) uint8 {
v := (*unsafeReflectValue)(unsafe.Pointer(&rv))
return *(*uint8)(v.ptr)
}
func rvGetUint16(rv reflect.Value) uint16 {
v := (*unsafeReflectValue)(unsafe.Pointer(&rv))
return *(*uint16)(v.ptr)
}
func rvGetUint32(rv reflect.Value) uint32 {
v := (*unsafeReflectValue)(unsafe.Pointer(&rv))
return *(*uint32)(v.ptr)
}
func rvGetUint64(rv reflect.Value) uint64 {
v := (*unsafeReflectValue)(unsafe.Pointer(&rv))
return *(*uint64)(v.ptr)
}
func rvGetUintptr(rv reflect.Value) uintptr {
v := (*unsafeReflectValue)(unsafe.Pointer(&rv))
return *(*uintptr)(v.ptr)
}
func rvLenMap(rv reflect.Value) int {
// maplen is not inlined, because as of go1.16beta, go:linkname's are not inlined.
// thus, faster to call rv.Len() directly.
//
// MARKER: review after https://github.com/golang/go/issues/20019 fixed.
// return rv.Len()
return len_map(rvRefPtr((*unsafeReflectValue)(unsafe.Pointer(&rv))))
}
// Note: it is hard to find len(...) of an array type,
// as that is a field in the arrayType representing the array, and hard to introspect.
//
// func rvLenArray(rv reflect.Value) int { return rv.Len() }
// ------------ map range and map indexing ----------
// regular calls to map via reflection: MapKeys, MapIndex, MapRange/MapIter etc
// will always allocate for each map key or value.
//
// It is more performant to provide a value that the map entry is set into,
// and that elides the allocation.
// go 1.4+ has runtime/hashmap.go or runtime/map.go which has a
// hIter struct with the first 2 values being key and value
// of the current iteration.
//
// This *hIter is passed to mapiterinit, mapiternext, mapiterkey, mapiterelem.
// We bypass the reflect wrapper functions and just use the *hIter directly.
//
// Though *hIter has many fields, we only care about the first 2.
//
// We directly embed this in unsafeMapIter below
//
// hiter is typically about 12 words, but we just fill up unsafeMapIter to 32 words,
// so it fills multiple cache lines and can give some extra space to accomodate small growth.
type unsafeMapIter struct {
mtyp, mptr unsafe.Pointer
k, v reflect.Value
kisref bool
visref bool
mapvalues bool
done bool
started bool
_ [3]byte // padding
it struct {
key unsafe.Pointer
value unsafe.Pointer
_ [20]uintptr // padding for other fields (to make up 32 words for enclosing struct)
}
}
func (t *unsafeMapIter) Next() (r bool) {
if t == nil || t.done {
return
}
if t.started {
mapiternext((unsafe.Pointer)(&t.it))
} else {
t.started = true
}
t.done = t.it.key == nil
if t.done {
return
}
if helperUnsafeDirectAssignMapEntry || t.kisref {
(*unsafeReflectValue)(unsafe.Pointer(&t.k)).ptr = t.it.key
} else {
k := (*unsafeReflectValue)(unsafe.Pointer(&t.k))
typedmemmove(k.typ, k.ptr, t.it.key)
}
if t.mapvalues {
if helperUnsafeDirectAssignMapEntry || t.visref {
(*unsafeReflectValue)(unsafe.Pointer(&t.v)).ptr = t.it.value
} else {
v := (*unsafeReflectValue)(unsafe.Pointer(&t.v))
typedmemmove(v.typ, v.ptr, t.it.value)
}
}
return true
}
func (t *unsafeMapIter) Key() (r reflect.Value) {
return t.k
}
func (t *unsafeMapIter) Value() (r reflect.Value) {
return t.v
}
func (t *unsafeMapIter) Done() {}
type mapIter struct {
unsafeMapIter
}
func mapRange(t *mapIter, m, k, v reflect.Value, mapvalues bool) {
if rvIsNil(m) {
t.done = true
return
}
t.done = false
t.started = false
t.mapvalues = mapvalues
// var urv *unsafeReflectValue
urv := (*unsafeReflectValue)(unsafe.Pointer(&m))
t.mtyp = urv.typ
t.mptr = rvRefPtr(urv)
// t.it = (*unsafeMapHashIter)(reflect_mapiterinit(t.mtyp, t.mptr))
mapiterinit(t.mtyp, t.mptr, unsafe.Pointer(&t.it))
t.k = k
t.kisref = refBitset.isset(byte(k.Kind()))
if mapvalues {
t.v = v
t.visref = refBitset.isset(byte(v.Kind()))
} else {
t.v = reflect.Value{}
}
}
// unsafeMapKVPtr returns the pointer if flagIndir, else it returns a pointer to the pointer.
// It is needed as maps always keep a reference to the underlying value.
func unsafeMapKVPtr(urv *unsafeReflectValue) unsafe.Pointer {
if urv.flag&unsafeFlagIndir == 0 {
return unsafe.Pointer(&urv.ptr)
}
return urv.ptr
}
// func mapDelete(m, k reflect.Value) {
// var urv = (*unsafeReflectValue)(unsafe.Pointer(&k))
// var kptr = unsafeMapKVPtr(urv)
// urv = (*unsafeReflectValue)(unsafe.Pointer(&m))
// mapdelete(urv.typ, rv2ptr(urv), kptr)
// }
// return an addressable reflect value that can be used in mapRange and mapGet operations.
//
// all calls to mapGet or mapRange will call here to get an addressable reflect.Value.
func mapAddrLoopvarRV(t reflect.Type, k reflect.Kind) (rv reflect.Value) {
// return rvZeroAddrK(t, k)
urv := (*unsafeReflectValue)(unsafe.Pointer(&rv))
urv.flag = uintptr(k) | unsafeFlagIndir | unsafeFlagAddr
urv.typ = ((*unsafeIntf)(unsafe.Pointer(&t))).ptr
// since we always set the ptr when helperUnsafeDirectAssignMapEntry=true,
// we should only allocate if it is not true
if !helperUnsafeDirectAssignMapEntry {
urv.ptr = unsafeNew(urv.typ)
}
return
}
// ---------- ENCODER optimized ---------------
func (e *Encoder) jsondriver() *jsonEncDriver {
return (*jsonEncDriver)((*unsafeIntf)(unsafe.Pointer(&e.e)).ptr)
}
func (d *Decoder) zerocopystate() bool {
return d.decByteState == decByteStateZerocopy && d.h.ZeroCopy
}
func (d *Decoder) stringZC(v []byte) (s string) {
if d.zerocopystate() {
return stringView(v)
}
return d.string(v)
}
func (d *Decoder) mapKeyString(callFnRvk *bool, kstrbs, kstr2bs *[]byte) string {
if !d.zerocopystate() {
*callFnRvk = true
if d.decByteState == decByteStateReuseBuf {
*kstrbs = append((*kstrbs)[:0], (*kstr2bs)...)
*kstr2bs = *kstrbs
}
}
return stringView(*kstr2bs)
}
// ---------- DECODER optimized ---------------
func (d *Decoder) checkBreak() bool {
// MARKER: jsonDecDriver.CheckBreak() costs over 80, and this isn't inlined.
// Consequently, there's no benefit in incurring the cost of this
// wrapping function checkBreak.
//
// It is faster to just call the interface method directly.
// if d.js {
// return d.jsondriver().CheckBreak()
// }
// if d.cbor {
// return d.cbordriver().CheckBreak()
// }
return d.d.CheckBreak()
}
func (d *Decoder) jsondriver() *jsonDecDriver {
return (*jsonDecDriver)((*unsafeIntf)(unsafe.Pointer(&d.d)).ptr)
}
// ---------- structFieldInfo optimized ---------------
func (n *structFieldInfoPathNode) rvField(v reflect.Value) (rv reflect.Value) {
// we already know this is exported, and maybe embedded (based on what si says)
uv := (*unsafeReflectValue)(unsafe.Pointer(&v))
urv := (*unsafeReflectValue)(unsafe.Pointer(&rv))
// clear flagEmbedRO if necessary, and inherit permission bits from v
urv.flag = uv.flag&(unsafeFlagStickyRO|unsafeFlagIndir|unsafeFlagAddr) | uintptr(n.kind)
urv.typ = ((*unsafeIntf)(unsafe.Pointer(&n.typ))).ptr
urv.ptr = unsafe.Pointer(uintptr(uv.ptr) + uintptr(n.offset))
return
}
// runtime chan and map are designed such that the first field is the count.
// len builtin uses this to get the length of a chan/map easily.
// leverage this knowledge, since maplen and chanlen functions from runtime package
// are go:linkname'd here, and thus not inlined as of go1.16beta
func len_map_chan(m unsafe.Pointer) int {
if m == nil {
return 0
}
return *((*int)(m))
}
func len_map(m unsafe.Pointer) int {
// return maplen(m)
return len_map_chan(m)
}
func len_chan(m unsafe.Pointer) int {
// return chanlen(m)
return len_map_chan(m)
}
func unsafeNew(typ unsafe.Pointer) unsafe.Pointer {
return mallocgc(rtsize2(typ), typ, true)
}
// ---------- go linknames (LINKED to runtime/reflect) ---------------
// MARKER: always check that these linknames match subsequent versions of go
//
// Note that as of Jan 2021 (go 1.16 release), go:linkname(s) are not inlined
// outside of the standard library use (e.g. within sync, reflect, etc).
// If these link'ed functions were normally inlined, calling them here would
// not necessarily give a performance boost, due to function overhead.
//
// However, it seems most of these functions are not inlined anyway,
// as only maplen, chanlen and mapaccess are small enough to get inlined.
//
// We checked this by going into $GOROOT/src/runtime and running:
// $ go build -tags codec.notfastpath -gcflags "-m=2"
// reflect.{unsafe_New, unsafe_NewArray} are not supported in gollvm,
// failing with "error: undefined reference" error.
// however, runtime.{mallocgc, newarray} are supported, so use that instead.
//go:linkname mallocgc runtime.mallocgc
//go:noescape
func mallocgc(size uintptr, typ unsafe.Pointer, needzero bool) unsafe.Pointer
//go:linkname newarray runtime.newarray
//go:noescape
func newarray(typ unsafe.Pointer, n int) unsafe.Pointer
//go:linkname mapiterinit runtime.mapiterinit
//go:noescape
func mapiterinit(typ unsafe.Pointer, m unsafe.Pointer, it unsafe.Pointer)
//go:linkname mapiternext runtime.mapiternext
//go:noescape
func mapiternext(it unsafe.Pointer) (key unsafe.Pointer)
//go:linkname mapdelete runtime.mapdelete
//go:noescape
func mapdelete(typ unsafe.Pointer, m unsafe.Pointer, key unsafe.Pointer)
//go:linkname mapassign runtime.mapassign
//go:noescape
func mapassign(typ unsafe.Pointer, m unsafe.Pointer, key unsafe.Pointer) unsafe.Pointer
//go:linkname mapaccess2 runtime.mapaccess2
//go:noescape
func mapaccess2(typ unsafe.Pointer, m unsafe.Pointer, key unsafe.Pointer) (val unsafe.Pointer, ok bool)
// reflect.typed{memmove, memclr, slicecopy} will handle checking if the type has pointers or not,
// and if a writeBarrier is needed, before delegating to the right method in the runtime.
//
// This is why we use the functions in reflect, and not the ones in runtime directly.
// Calling runtime.XXX here will lead to memory issues.
//go:linkname typedslicecopy reflect.typedslicecopy
//go:noescape
func typedslicecopy(elemType unsafe.Pointer, dst, src unsafeSlice) int
//go:linkname typedmemmove reflect.typedmemmove
//go:noescape
func typedmemmove(typ unsafe.Pointer, dst, src unsafe.Pointer)
//go:linkname typedmemclr reflect.typedmemclr
//go:noescape
func typedmemclr(typ unsafe.Pointer, dst unsafe.Pointer)