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// Copyright 2014 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package runtime
import (
"internal/cpu"
"runtime/internal/sys"
"unsafe"
)
const (
c0 = uintptr((8-sys.PtrSize)/4*2860486313 + (sys.PtrSize-4)/4*33054211828000289)
c1 = uintptr((8-sys.PtrSize)/4*3267000013 + (sys.PtrSize-4)/4*23344194077549503)
)
// type algorithms - known to compiler
const (
alg_NOEQ = iota
alg_MEM0
alg_MEM8
alg_MEM16
alg_MEM32
alg_MEM64
alg_MEM128
alg_STRING
alg_INTER
alg_NILINTER
alg_FLOAT32
alg_FLOAT64
alg_CPLX64
alg_CPLX128
alg_max
)
// typeAlg is also copied/used in reflect/type.go.
// keep them in sync.
type typeAlg struct {
// function for hashing objects of this type
// (ptr to object, seed) -> hash
hash func(unsafe.Pointer, uintptr) uintptr
// function for comparing objects of this type
// (ptr to object A, ptr to object B) -> ==?
equal func(unsafe.Pointer, unsafe.Pointer) bool
}
func memhash0(p unsafe.Pointer, h uintptr) uintptr {
return h
}
func memhash8(p unsafe.Pointer, h uintptr) uintptr {
return memhash(p, h, 1)
}
func memhash16(p unsafe.Pointer, h uintptr) uintptr {
return memhash(p, h, 2)
}
func memhash128(p unsafe.Pointer, h uintptr) uintptr {
return memhash(p, h, 16)
}
//go:nosplit
func memhash_varlen(p unsafe.Pointer, h uintptr) uintptr {
ptr := getclosureptr()
size := *(*uintptr)(unsafe.Pointer(ptr + unsafe.Sizeof(h)))
return memhash(p, h, size)
}
var algarray = [alg_max]typeAlg{
alg_NOEQ: {nil, nil},
alg_MEM0: {memhash0, memequal0},
alg_MEM8: {memhash8, memequal8},
alg_MEM16: {memhash16, memequal16},
alg_MEM32: {memhash32, memequal32},
alg_MEM64: {memhash64, memequal64},
alg_MEM128: {memhash128, memequal128},
alg_STRING: {strhash, strequal},
alg_INTER: {interhash, interequal},
alg_NILINTER: {nilinterhash, nilinterequal},
alg_FLOAT32: {f32hash, f32equal},
alg_FLOAT64: {f64hash, f64equal},
alg_CPLX64: {c64hash, c64equal},
alg_CPLX128: {c128hash, c128equal},
}
var useAeshash bool
// in asm_*.s
func aeshash(p unsafe.Pointer, h, s uintptr) uintptr
func aeshash32(p unsafe.Pointer, h uintptr) uintptr
func aeshash64(p unsafe.Pointer, h uintptr) uintptr
func aeshashstr(p unsafe.Pointer, h uintptr) uintptr
func strhash(a unsafe.Pointer, h uintptr) uintptr {
x := (*stringStruct)(a)
return memhash(x.str, h, uintptr(x.len))
}
// NOTE: Because NaN != NaN, a map can contain any
// number of (mostly useless) entries keyed with NaNs.
// To avoid long hash chains, we assign a random number
// as the hash value for a NaN.
func f32hash(p unsafe.Pointer, h uintptr) uintptr {
f := *(*float32)(p)
switch {
case f == 0:
return c1 * (c0 ^ h) // +0, -0
case f != f:
return c1 * (c0 ^ h ^ uintptr(fastrand())) // any kind of NaN
default:
return memhash(p, h, 4)
}
}
func f64hash(p unsafe.Pointer, h uintptr) uintptr {
f := *(*float64)(p)
switch {
case f == 0:
return c1 * (c0 ^ h) // +0, -0
case f != f:
return c1 * (c0 ^ h ^ uintptr(fastrand())) // any kind of NaN
default:
return memhash(p, h, 8)
}
}
func c64hash(p unsafe.Pointer, h uintptr) uintptr {
x := (*[2]float32)(p)
return f32hash(unsafe.Pointer(&x[1]), f32hash(unsafe.Pointer(&x[0]), h))
}
func c128hash(p unsafe.Pointer, h uintptr) uintptr {
x := (*[2]float64)(p)
return f64hash(unsafe.Pointer(&x[1]), f64hash(unsafe.Pointer(&x[0]), h))
}
func interhash(p unsafe.Pointer, h uintptr) uintptr {
a := (*iface)(p)
tab := a.tab
if tab == nil {
return h
}
t := tab._type
fn := t.alg.hash
if fn == nil {
panic(errorString("hash of unhashable type " + t.string()))
}
if isDirectIface(t) {
return c1 * fn(unsafe.Pointer(&a.data), h^c0)
} else {
return c1 * fn(a.data, h^c0)
}
}
func nilinterhash(p unsafe.Pointer, h uintptr) uintptr {
a := (*eface)(p)
t := a._type
if t == nil {
return h
}
fn := t.alg.hash
if fn == nil {
panic(errorString("hash of unhashable type " + t.string()))
}
if isDirectIface(t) {
return c1 * fn(unsafe.Pointer(&a.data), h^c0)
} else {
return c1 * fn(a.data, h^c0)
}
}
func memequal0(p, q unsafe.Pointer) bool {
return true
}
func memequal8(p, q unsafe.Pointer) bool {
return *(*int8)(p) == *(*int8)(q)
}
func memequal16(p, q unsafe.Pointer) bool {
return *(*int16)(p) == *(*int16)(q)
}
func memequal32(p, q unsafe.Pointer) bool {
return *(*int32)(p) == *(*int32)(q)
}
func memequal64(p, q unsafe.Pointer) bool {
return *(*int64)(p) == *(*int64)(q)
}
func memequal128(p, q unsafe.Pointer) bool {
return *(*[2]int64)(p) == *(*[2]int64)(q)
}
func f32equal(p, q unsafe.Pointer) bool {
return *(*float32)(p) == *(*float32)(q)
}
func f64equal(p, q unsafe.Pointer) bool {
return *(*float64)(p) == *(*float64)(q)
}
func c64equal(p, q unsafe.Pointer) bool {
return *(*complex64)(p) == *(*complex64)(q)
}
func c128equal(p, q unsafe.Pointer) bool {
return *(*complex128)(p) == *(*complex128)(q)
}
func strequal(p, q unsafe.Pointer) bool {
return *(*string)(p) == *(*string)(q)
}
func interequal(p, q unsafe.Pointer) bool {
x := *(*iface)(p)
y := *(*iface)(q)
return x.tab == y.tab && ifaceeq(x.tab, x.data, y.data)
}
func nilinterequal(p, q unsafe.Pointer) bool {
x := *(*eface)(p)
y := *(*eface)(q)
return x._type == y._type && efaceeq(x._type, x.data, y.data)
}
func efaceeq(t *_type, x, y unsafe.Pointer) bool {
if t == nil {
return true
}
eq := t.alg.equal
if eq == nil {
panic(errorString("comparing uncomparable type " + t.string()))
}
if isDirectIface(t) {
// Direct interface types are ptr, chan, map, func, and single-element structs/arrays thereof.
// Maps and funcs are not comparable, so they can't reach here.
// Ptrs, chans, and single-element items can be compared directly using ==.
return x == y
}
return eq(x, y)
}
func ifaceeq(tab *itab, x, y unsafe.Pointer) bool {
if tab == nil {
return true
}
t := tab._type
eq := t.alg.equal
if eq == nil {
panic(errorString("comparing uncomparable type " + t.string()))
}
if isDirectIface(t) {
// See comment in efaceeq.
return x == y
}
return eq(x, y)
}
// Testing adapters for hash quality tests (see hash_test.go)
func stringHash(s string, seed uintptr) uintptr {
return algarray[alg_STRING].hash(noescape(unsafe.Pointer(&s)), seed)
}
func bytesHash(b []byte, seed uintptr) uintptr {
s := (*slice)(unsafe.Pointer(&b))
return memhash(s.array, seed, uintptr(s.len))
}
func int32Hash(i uint32, seed uintptr) uintptr {
return algarray[alg_MEM32].hash(noescape(unsafe.Pointer(&i)), seed)
}
func int64Hash(i uint64, seed uintptr) uintptr {
return algarray[alg_MEM64].hash(noescape(unsafe.Pointer(&i)), seed)
}
func efaceHash(i interface{}, seed uintptr) uintptr {
return algarray[alg_NILINTER].hash(noescape(unsafe.Pointer(&i)), seed)
}
func ifaceHash(i interface {
F()
}, seed uintptr) uintptr {
return algarray[alg_INTER].hash(noescape(unsafe.Pointer(&i)), seed)
}
const hashRandomBytes = sys.PtrSize / 4 * 64
// used in asm_{386,amd64,arm64}.s to seed the hash function
var aeskeysched [hashRandomBytes]byte
// used in hash{32,64}.go to seed the hash function
var hashkey [4]uintptr
func alginit() {
// Install AES hash algorithms if the instructions needed are present.
if (GOARCH == "386" || GOARCH == "amd64") &&
GOOS != "nacl" &&
cpu.X86.HasAES && // AESENC
cpu.X86.HasSSSE3 && // PSHUFB
cpu.X86.HasSSE41 { // PINSR{D,Q}
initAlgAES()
return
}
if GOARCH == "arm64" && cpu.ARM64.HasAES {
initAlgAES()
return
}
getRandomData((*[len(hashkey) * sys.PtrSize]byte)(unsafe.Pointer(&hashkey))[:])
hashkey[0] |= 1 // make sure these numbers are odd
hashkey[1] |= 1
hashkey[2] |= 1
hashkey[3] |= 1
}
func initAlgAES() {
if GOOS == "aix" {
// runtime.algarray is immutable on AIX: see cmd/link/internal/ld/xcoff.go
return
}
useAeshash = true
algarray[alg_MEM32].hash = aeshash32
algarray[alg_MEM64].hash = aeshash64
algarray[alg_STRING].hash = aeshashstr
// Initialize with random data so hash collisions will be hard to engineer.
getRandomData(aeskeysched[:])
}
// Note: These routines perform the read with an native endianness.
func readUnaligned32(p unsafe.Pointer) uint32 {
q := (*[4]byte)(p)
if sys.BigEndian {
return uint32(q[3]) | uint32(q[2])<<8 | uint32(q[1])<<16 | uint32(q[0])<<24
}
return uint32(q[0]) | uint32(q[1])<<8 | uint32(q[2])<<16 | uint32(q[3])<<24
}
func readUnaligned64(p unsafe.Pointer) uint64 {
q := (*[8]byte)(p)
if sys.BigEndian {
return uint64(q[7]) | uint64(q[6])<<8 | uint64(q[5])<<16 | uint64(q[4])<<24 |
uint64(q[3])<<32 | uint64(q[2])<<40 | uint64(q[1])<<48 | uint64(q[0])<<56
}
return uint64(q[0]) | uint64(q[1])<<8 | uint64(q[2])<<16 | uint64(q[3])<<24 | uint64(q[4])<<32 | uint64(q[5])<<40 | uint64(q[6])<<48 | uint64(q[7])<<56
}
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