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-rw-r--r--src/runtime/alg.go370
1 files changed, 370 insertions, 0 deletions
diff --git a/src/runtime/alg.go b/src/runtime/alg.go
new file mode 100644
index 0000000..1b3bf11
--- /dev/null
+++ b/src/runtime/alg.go
@@ -0,0 +1,370 @@
+// 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 len(i.mhdr) == 0 {
+ 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
+}