| // 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) |
| ) |
| |
| 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) |
| } |
| |
| // runtime variable to check if the processor we're running on |
| // actually supports the instructions used by the AES-based |
| // hash implementation. |
| var useAeshash bool |
| |
| // in asm_*.s |
| func memhash(p unsafe.Pointer, h, s uintptr) uintptr |
| func memhash32(p unsafe.Pointer, h uintptr) uintptr |
| func memhash64(p unsafe.Pointer, h uintptr) uintptr |
| func strhash(p unsafe.Pointer, h uintptr) uintptr |
| |
| func strhashFallback(a unsafe.Pointer, h uintptr) uintptr { |
| x := (*stringStruct)(a) |
| return memhashFallback(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 |
| if t.equal == nil { |
| // Check hashability here. We could do this check inside |
| // typehash, but we want to report the topmost type in |
| // the error text (e.g. in a struct with a field of slice type |
| // we want to report the struct, not the slice). |
| panic(errorString("hash of unhashable type " + t.string())) |
| } |
| if isDirectIface(t) { |
| return c1 * typehash(t, unsafe.Pointer(&a.data), h^c0) |
| } else { |
| return c1 * typehash(t, a.data, h^c0) |
| } |
| } |
| |
| func nilinterhash(p unsafe.Pointer, h uintptr) uintptr { |
| a := (*eface)(p) |
| t := a._type |
| if t == nil { |
| return h |
| } |
| if t.equal == nil { |
| // See comment in interhash above. |
| panic(errorString("hash of unhashable type " + t.string())) |
| } |
| if isDirectIface(t) { |
| return c1 * typehash(t, unsafe.Pointer(&a.data), h^c0) |
| } else { |
| return c1 * typehash(t, a.data, h^c0) |
| } |
| } |
| |
| // typehash computes the hash of the object of type t at address p. |
| // h is the seed. |
| // This function is seldom used. Most maps use for hashing either |
| // fixed functions (e.g. f32hash) or compiler-generated functions |
| // (e.g. for a type like struct { x, y string }). This implementation |
| // is slower but more general and is used for hashing interface types |
| // (called from interhash or nilinterhash, above) or for hashing in |
| // maps generated by reflect.MapOf (reflect_typehash, below). |
| // Note: this function must match the compiler generated |
| // functions exactly. See issue 37716. |
| func typehash(t *_type, p unsafe.Pointer, h uintptr) uintptr { |
| if t.tflag&tflagRegularMemory != 0 { |
| // Handle ptr sizes specially, see issue 37086. |
| switch t.size { |
| case 4: |
| return memhash32(p, h) |
| case 8: |
| return memhash64(p, h) |
| default: |
| return memhash(p, h, t.size) |
| } |
| } |
| switch t.kind & kindMask { |
| case kindFloat32: |
| return f32hash(p, h) |
| case kindFloat64: |
| return f64hash(p, h) |
| case kindComplex64: |
| return c64hash(p, h) |
| case kindComplex128: |
| return c128hash(p, h) |
| case kindString: |
| return strhash(p, h) |
| case kindInterface: |
| i := (*interfacetype)(unsafe.Pointer(t)) |
| if i.isEmpty() { |
| return nilinterhash(p, h) |
| } |
| return interhash(p, h) |
| case kindArray: |
| a := (*arraytype)(unsafe.Pointer(t)) |
| for i := uintptr(0); i < a.len; i++ { |
| h = typehash(a.elem, add(p, i*a.elem.size), h) |
| } |
| return h |
| case kindStruct: |
| s := (*structtype)(unsafe.Pointer(t)) |
| memStart := uintptr(0) |
| memEnd := uintptr(0) |
| for _, f := range s.fields { |
| if memEnd > memStart && (f.name.isBlank() || f.offset() != memEnd || f.typ.tflag&tflagRegularMemory == 0) { |
| // flush any pending regular memory hashing |
| h = memhash(add(p, memStart), h, memEnd-memStart) |
| memStart = memEnd |
| } |
| if f.name.isBlank() { |
| continue |
| } |
| if f.typ.tflag&tflagRegularMemory == 0 { |
| h = typehash(f.typ, add(p, f.offset()), h) |
| continue |
| } |
| if memStart == memEnd { |
| memStart = f.offset() |
| } |
| memEnd = f.offset() + f.typ.size |
| } |
| if memEnd > memStart { |
| h = memhash(add(p, memStart), h, memEnd-memStart) |
| } |
| return h |
| default: |
| // Should never happen, as typehash should only be called |
| // with comparable types. |
| panic(errorString("hash of unhashable type " + t.string())) |
| } |
| } |
| |
| //go:linkname reflect_typehash reflect.typehash |
| func reflect_typehash(t *_type, p unsafe.Pointer, h uintptr) uintptr { |
| return typehash(t, p, h) |
| } |
| |
| 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.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.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 strhash(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 memhash32(noescape(unsafe.Pointer(&i)), seed) |
| } |
| |
| func int64Hash(i uint64, seed uintptr) uintptr { |
| return memhash64(noescape(unsafe.Pointer(&i)), seed) |
| } |
| |
| func efaceHash(i interface{}, seed uintptr) uintptr { |
| return nilinterhash(noescape(unsafe.Pointer(&i)), seed) |
| } |
| |
| func ifaceHash(i interface { |
| F() |
| }, seed uintptr) uintptr { |
| return interhash(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") && |
| 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() { |
| useAeshash = true |
| // Initialize with random data so hash collisions will be hard to engineer. |
| getRandomData(aeskeysched[:]) |
| } |
| |
| // Note: These routines perform the read with a 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 |
| } |
