517 lines
13 KiB
Go
517 lines
13 KiB
Go
// Copyright 2014 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package runtime
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import (
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"internal/cpu"
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"internal/goarch"
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"unsafe"
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)
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// For gccgo, use go:linkname to export compiler-called functions.
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//
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//go:linkname memhash0
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//go:linkname memhash8
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//go:linkname memhash16
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//go:linkname memhash32
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//go:linkname memhash64
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//go:linkname memhash128
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//go:linkname strhash
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//go:linkname f32hash
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//go:linkname f64hash
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//go:linkname c64hash
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//go:linkname c128hash
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//go:linkname interhash
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//go:linkname nilinterhash
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//go:linkname memequal0
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//go:linkname memequal8
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//go:linkname memequal16
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//go:linkname memequal32
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//go:linkname memequal64
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//go:linkname memequal128
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//go:linkname strequal
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//go:linkname f32equal
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//go:linkname f64equal
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//go:linkname c64equal
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//go:linkname c128equal
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//go:linkname interequal
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//go:linkname nilinterequal
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//go:linkname efaceeq
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//go:linkname ifaceeq
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//go:linkname ifacevaleq
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//go:linkname ifaceefaceeq
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//go:linkname efacevaleq
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//go:linkname cmpstring
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//
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// Temporary to be called from C code.
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//go:linkname alginit
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const (
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c0 = uintptr((8-goarch.PtrSize)/4*2860486313 + (goarch.PtrSize-4)/4*33054211828000289)
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c1 = uintptr((8-goarch.PtrSize)/4*3267000013 + (goarch.PtrSize-4)/4*23344194077549503)
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)
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func memhash0(p unsafe.Pointer, h uintptr) uintptr {
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return h
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}
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func memhash8(p unsafe.Pointer, h uintptr) uintptr {
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return memhash(p, h, 1)
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}
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func memhash16(p unsafe.Pointer, h uintptr) uintptr {
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return memhash(p, h, 2)
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}
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func memhash128(p unsafe.Pointer, h uintptr) uintptr {
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return memhash(p, h, 16)
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}
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// runtime variable to check if the processor we're running on
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// actually supports the instructions used by the AES-based
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// hash implementation.
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var useAeshash bool
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// in C code
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func aeshashbody(p unsafe.Pointer, h, s uintptr, sched []byte) uintptr
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func aeshash(p unsafe.Pointer, h, s uintptr) uintptr {
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return aeshashbody(p, h, s, aeskeysched[:])
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}
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func aeshashstr(p unsafe.Pointer, h uintptr) uintptr {
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ps := (*stringStruct)(p)
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return aeshashbody(unsafe.Pointer(ps.str), h, uintptr(ps.len), aeskeysched[:])
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}
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func strhash(a unsafe.Pointer, h uintptr) uintptr {
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x := (*stringStruct)(a)
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return memhash(x.str, h, uintptr(x.len))
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}
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// NOTE: Because NaN != NaN, a map can contain any
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// number of (mostly useless) entries keyed with NaNs.
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// To avoid long hash chains, we assign a random number
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// as the hash value for a NaN.
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func f32hash(p unsafe.Pointer, h uintptr) uintptr {
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f := *(*float32)(p)
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switch {
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case f == 0:
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return c1 * (c0 ^ h) // +0, -0
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case f != f:
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return c1 * (c0 ^ h ^ uintptr(fastrand())) // any kind of NaN
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default:
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return memhash(p, h, 4)
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}
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}
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func f64hash(p unsafe.Pointer, h uintptr) uintptr {
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f := *(*float64)(p)
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switch {
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case f == 0:
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return c1 * (c0 ^ h) // +0, -0
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case f != f:
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return c1 * (c0 ^ h ^ uintptr(fastrand())) // any kind of NaN
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default:
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return memhash(p, h, 8)
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}
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}
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func c64hash(p unsafe.Pointer, h uintptr) uintptr {
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x := (*[2]float32)(p)
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return f32hash(unsafe.Pointer(&x[1]), f32hash(unsafe.Pointer(&x[0]), h))
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}
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func c128hash(p unsafe.Pointer, h uintptr) uintptr {
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x := (*[2]float64)(p)
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return f64hash(unsafe.Pointer(&x[1]), f64hash(unsafe.Pointer(&x[0]), h))
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}
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func interhash(p unsafe.Pointer, h uintptr) uintptr {
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a := (*iface)(p)
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tab := a.tab
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if tab == nil {
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return h
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}
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t := *(**_type)(tab)
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if t.equal == nil {
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// Check hashability here. We could do this check inside
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// typehash, but we want to report the topmost type in
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// the error text (e.g. in a struct with a field of slice type
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// we want to report the struct, not the slice).
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panic(errorString("hash of unhashable type " + t.string()))
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}
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if isDirectIface(t) {
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return c1 * typehash(t, unsafe.Pointer(&a.data), h^c0)
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} else {
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return c1 * typehash(t, a.data, h^c0)
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}
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}
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func nilinterhash(p unsafe.Pointer, h uintptr) uintptr {
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a := (*eface)(p)
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t := a._type
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if t == nil {
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return h
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}
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if t.equal == nil {
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// See comment in interhash above.
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panic(errorString("hash of unhashable type " + t.string()))
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}
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if isDirectIface(t) {
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return c1 * typehash(t, unsafe.Pointer(&a.data), h^c0)
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} else {
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return c1 * typehash(t, a.data, h^c0)
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}
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}
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// typehash computes the hash of the object of type t at address p.
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// h is the seed.
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// This function is seldom used. Most maps use for hashing either
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// fixed functions (e.g. f32hash) or compiler-generated functions
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// (e.g. for a type like struct { x, y string }). This implementation
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// is slower but more general and is used for hashing interface types
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// (called from interhash or nilinterhash, above) or for hashing in
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// maps generated by reflect.MapOf (reflect_typehash, below).
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// Note: this function must match the compiler generated
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// functions exactly. See issue 37716.
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func typehash(t *_type, p unsafe.Pointer, h uintptr) uintptr {
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if t.tflag&tflagRegularMemory != 0 {
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// Handle ptr sizes specially, see issue 37086.
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switch t.size {
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case 4:
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return memhash32(p, h)
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case 8:
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return memhash64(p, h)
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default:
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return memhash(p, h, t.size)
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}
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}
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switch t.kind & kindMask {
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case kindFloat32:
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return f32hash(p, h)
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case kindFloat64:
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return f64hash(p, h)
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case kindComplex64:
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return c64hash(p, h)
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case kindComplex128:
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return c128hash(p, h)
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case kindString:
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return strhash(p, h)
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case kindInterface:
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i := (*interfacetype)(unsafe.Pointer(t))
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if len(i.methods) == 0 {
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return nilinterhash(p, h)
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}
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return interhash(p, h)
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case kindArray:
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a := (*arraytype)(unsafe.Pointer(t))
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for i := uintptr(0); i < a.len; i++ {
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h = typehash(a.elem, add(p, i*a.elem.size), h)
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}
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return h
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case kindStruct:
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s := (*structtype)(unsafe.Pointer(t))
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for _, f := range s.fields {
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if f.name != nil && *f.name == "_" {
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continue
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}
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h = typehash(f.typ, add(p, f.offset()), h)
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}
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return h
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default:
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// Should never happen, as typehash should only be called
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// with comparable types.
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panic(errorString("hash of unhashable type " + t.string()))
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}
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}
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//go:linkname reflect_typehash reflect.typehash
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func reflect_typehash(t *_type, p unsafe.Pointer, h uintptr) uintptr {
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return typehash(t, p, h)
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}
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func memequal0(p, q unsafe.Pointer) bool {
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return true
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}
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func memequal8(p, q unsafe.Pointer) bool {
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return *(*int8)(p) == *(*int8)(q)
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}
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func memequal16(p, q unsafe.Pointer) bool {
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return *(*int16)(p) == *(*int16)(q)
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}
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func memequal32(p, q unsafe.Pointer) bool {
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return *(*int32)(p) == *(*int32)(q)
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}
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func memequal64(p, q unsafe.Pointer) bool {
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return *(*int64)(p) == *(*int64)(q)
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}
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func memequal128(p, q unsafe.Pointer) bool {
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return *(*[2]int64)(p) == *(*[2]int64)(q)
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}
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func f32equal(p, q unsafe.Pointer) bool {
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return *(*float32)(p) == *(*float32)(q)
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}
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func f64equal(p, q unsafe.Pointer) bool {
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return *(*float64)(p) == *(*float64)(q)
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}
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func c64equal(p, q unsafe.Pointer) bool {
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return *(*complex64)(p) == *(*complex64)(q)
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}
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func c128equal(p, q unsafe.Pointer) bool {
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return *(*complex128)(p) == *(*complex128)(q)
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}
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func strequal(p, q unsafe.Pointer) bool {
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return *(*string)(p) == *(*string)(q)
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}
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func interequal(p, q unsafe.Pointer) bool {
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return ifaceeq(*(*iface)(p), *(*iface)(q))
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}
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func nilinterequal(p, q unsafe.Pointer) bool {
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return efaceeq(*(*eface)(p), *(*eface)(q))
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}
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func efaceeq(x, y eface) bool {
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t := x._type
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if !eqtype(t, y._type) {
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return false
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}
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if t == nil {
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return true
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}
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eq := t.equal
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if eq == nil {
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panic(errorString("comparing uncomparable type " + t.string()))
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}
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if isDirectIface(t) {
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return x.data == y.data
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}
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return eq(x.data, y.data)
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}
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func ifaceeq(x, y iface) bool {
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xtab := x.tab
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if xtab == nil && y.tab == nil {
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return true
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}
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if xtab == nil || y.tab == nil {
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return false
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}
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t := *(**_type)(xtab)
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if !eqtype(t, *(**_type)(y.tab)) {
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return false
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}
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eq := t.equal
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if eq == nil {
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panic(errorString("comparing uncomparable type " + t.string()))
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}
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if isDirectIface(t) {
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// Direct interface types are ptr, chan, map, func, and single-element structs/arrays thereof.
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// Maps and funcs are not comparable, so they can't reach here.
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// Ptrs, chans, and single-element items can be compared directly using ==.
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return x.data == y.data
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}
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return eq(x.data, y.data)
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}
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func ifacevaleq(x iface, t *_type, p unsafe.Pointer) bool {
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if x.tab == nil {
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return false
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}
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xt := *(**_type)(x.tab)
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if !eqtype(xt, t) {
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return false
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}
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eq := t.equal
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if eq == nil {
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panic(errorString("comparing uncomparable type " + t.string()))
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}
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if isDirectIface(t) {
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return x.data == p
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}
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return eq(x.data, p)
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}
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func ifaceefaceeq(x iface, y eface) bool {
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if x.tab == nil && y._type == nil {
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return true
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}
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if x.tab == nil || y._type == nil {
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return false
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}
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xt := *(**_type)(x.tab)
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if !eqtype(xt, y._type) {
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return false
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}
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eq := xt.equal
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if eq == nil {
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panic(errorString("comparing uncomparable type " + xt.string()))
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}
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if isDirectIface(xt) {
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return x.data == y.data
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}
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return eq(x.data, y.data)
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}
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func efacevaleq(x eface, t *_type, p unsafe.Pointer) bool {
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if x._type == nil {
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return false
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}
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if !eqtype(x._type, t) {
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return false
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}
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eq := t.equal
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if eq == nil {
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panic(errorString("comparing uncomparable type " + t.string()))
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}
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if isDirectIface(t) {
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// See comment in efaceeq.
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return x.data == p
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}
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return eq(x.data, p)
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}
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func cmpstring(x, y string) int {
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a := stringStructOf(&x)
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b := stringStructOf(&y)
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l := a.len
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if l > b.len {
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l = b.len
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}
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i := memcmp(unsafe.Pointer(a.str), unsafe.Pointer(b.str), uintptr(l))
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if i != 0 {
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return int(i)
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}
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if a.len < b.len {
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return -1
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} else if a.len > b.len {
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return 1
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}
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return 0
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}
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// For the unsafe.Pointer type descriptor in libgo/runtime/go-unsafe-pointer.c.
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func pointerhash(p unsafe.Pointer, h uintptr) uintptr {
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return memhash(p, h, unsafe.Sizeof(unsafe.Pointer))
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}
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func pointerequal(p, q unsafe.Pointer) bool {
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return *(*unsafe.Pointer)(p) == *(*unsafe.Pointer)(q)
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}
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// Force the creation of function descriptors for equality and hash
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// functions. These will be referenced directly by the compiler.
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var _ = memhash
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var _ = memhash0
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var _ = memhash8
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var _ = memhash16
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var _ = memhash32
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var _ = memhash64
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var _ = memhash128
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var _ = strhash
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var _ = f32hash
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var _ = f64hash
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var _ = c64hash
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var _ = c128hash
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var _ = interhash
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var _ = nilinterhash
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var _ = memequal0
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var _ = memequal8
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var _ = memequal16
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var _ = memequal32
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var _ = memequal64
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var _ = memequal128
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var _ = f32equal
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var _ = f64equal
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var _ = c64equal
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var _ = c128equal
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var _ = strequal
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var _ = interequal
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var _ = nilinterequal
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var _ = pointerhash
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var _ = pointerequal
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// Testing adapters for hash quality tests (see hash_test.go)
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func stringHash(s string, seed uintptr) uintptr {
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return strhash(noescape(unsafe.Pointer(&s)), seed)
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}
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func bytesHash(b []byte, seed uintptr) uintptr {
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s := (*slice)(unsafe.Pointer(&b))
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return memhash(s.array, seed, uintptr(s.len))
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}
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func int32Hash(i uint32, seed uintptr) uintptr {
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return memhash32(noescape(unsafe.Pointer(&i)), seed)
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}
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func int64Hash(i uint64, seed uintptr) uintptr {
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return memhash64(noescape(unsafe.Pointer(&i)), seed)
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}
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func efaceHash(i any, seed uintptr) uintptr {
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return nilinterhash(noescape(unsafe.Pointer(&i)), seed)
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}
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func ifaceHash(i interface {
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F()
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}, seed uintptr) uintptr {
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return interhash(noescape(unsafe.Pointer(&i)), seed)
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}
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const hashRandomBytes = goarch.PtrSize / 4 * 64
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// used in asm_{386,amd64,arm64}.s to seed the hash function
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var aeskeysched [hashRandomBytes]byte
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// used in hash{32,64}.go to seed the hash function
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var hashkey [4]uintptr
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func alginit() {
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// Install AES hash algorithms if the instructions needed are present.
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if (GOARCH == "386" || GOARCH == "amd64") &&
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support_aes &&
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cpu.X86.HasAES && // AESENC
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cpu.X86.HasSSSE3 && // PSHUFB
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cpu.X86.HasSSE41 { // PINSR{D,Q}
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initAlgAES()
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return
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}
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if GOARCH == "arm64" && cpu.ARM64.HasAES {
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initAlgAES()
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return
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}
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getRandomData((*[len(hashkey) * goarch.PtrSize]byte)(unsafe.Pointer(&hashkey))[:])
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hashkey[0] |= 1 // make sure these numbers are odd
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hashkey[1] |= 1
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hashkey[2] |= 1
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hashkey[3] |= 1
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}
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func initAlgAES() {
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useAeshash = true
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// Initialize with random data so hash collisions will be hard to engineer.
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getRandomData(aeskeysched[:])
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}
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// Note: These routines perform the read with a native endianness.
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func readUnaligned32(p unsafe.Pointer) uint32 {
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q := (*[4]byte)(p)
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if goarch.BigEndian {
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return uint32(q[3]) | uint32(q[2])<<8 | uint32(q[1])<<16 | uint32(q[0])<<24
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}
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return uint32(q[0]) | uint32(q[1])<<8 | uint32(q[2])<<16 | uint32(q[3])<<24
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}
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func readUnaligned64(p unsafe.Pointer) uint64 {
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q := (*[8]byte)(p)
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if goarch.BigEndian {
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return uint64(q[7]) | uint64(q[6])<<8 | uint64(q[5])<<16 | uint64(q[4])<<24 |
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uint64(q[3])<<32 | uint64(q[2])<<40 | uint64(q[1])<<48 | uint64(q[0])<<56
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}
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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
|
|
}
|