From: Michael Anthony Knyszek Date: Fri, 24 Sep 2021 16:01:03 +0000 (+0000) Subject: runtime/internal/atomic: add atomic types for all functions X-Git-Tag: go1.18beta1~823 X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=3ec8d4b5ed5db74f84f8d493e4160e97481e436d;p=gostls13.git runtime/internal/atomic: add atomic types for all functions Change-Id: I74f365316484feb819c31c77fbffd78fadfe32a9 Reviewed-on: https://go-review.googlesource.com/c/go/+/356169 Trust: Michael Knyszek Run-TryBot: Michael Knyszek TryBot-Result: Go Bot Reviewed-by: Austin Clements Reviewed-by: Michael Pratt --- diff --git a/src/runtime/internal/atomic/doc.go b/src/runtime/internal/atomic/doc.go new file mode 100644 index 0000000000..08e6b6ce0b --- /dev/null +++ b/src/runtime/internal/atomic/doc.go @@ -0,0 +1,18 @@ +// Copyright 2021 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 atomic provides atomic operations, independent of sync/atomic, +to the runtime. + +On most platforms, the compiler is aware of the functions defined +in this package, and they're replaced with platform-specific intrinsics. +On other platforms, generic implementations are made available. + +Unless otherwise noted, operations defined in this package are sequentially +consistent across threads with respect to the values they manipulate. More +specifically, operations that happen in a specific order on one thread, +will always be observed to happen in exactly that order by another thread. +*/ +package atomic diff --git a/src/runtime/internal/atomic/types.go b/src/runtime/internal/atomic/types.go new file mode 100644 index 0000000000..1a240d7c91 --- /dev/null +++ b/src/runtime/internal/atomic/types.go @@ -0,0 +1,395 @@ +// Copyright 2021 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 atomic + +import "unsafe" + +// Int32 is an atomically accessed int32 value. +// +// An Int32 must not be copied. +type Int32 struct { + noCopy noCopy + value int32 +} + +// Load accesses and returns the value atomically. +func (i *Int32) Load() int32 { + return Loadint32(&i.value) +} + +// Store updates the value atomically. +func (i *Int32) Store(value int32) { + Storeint32(&i.value, value) +} + +// CompareAndSwap atomically compares i's value with old, +// and if they're equal, swaps i's value with new. +// +// Returns true if the operation succeeded. +func (i *Int32) CompareAndSwap(old, new int32) bool { + return Casint32(&i.value, old, new) +} + +// Swap replaces i's value with new, returning +// i's value before the replacement. +func (i *Int32) Swap(new int32) int32 { + return Xchgint32(&i.value, new) +} + +// Add adds delta to i atomically, returning +// the new updated value. +// +// This operation wraps around in the usual +// two's-complement way. +func (i *Int32) Add(delta int32) int32 { + return Xaddint32(&i.value, delta) +} + +// Int64 is an atomically accessed int64 value. +// +// An Int64 must not be copied. +type Int64 struct { + noCopy noCopy + value int64 +} + +// Load accesses and returns the value atomically. +func (i *Int64) Load() int64 { + return Loadint64(&i.value) +} + +// Store updates the value atomically. +func (i *Int64) Store(value int64) { + Storeint64(&i.value, value) +} + +// CompareAndSwap atomically compares i's value with old, +// and if they're equal, swaps i's value with new. +// +// Returns true if the operation succeeded. +func (i *Int64) CompareAndSwap(old, new int64) bool { + return Casint64(&i.value, old, new) +} + +// Swap replaces i's value with new, returning +// i's value before the replacement. +func (i *Int64) Swap(new int64) int64 { + return Xchgint64(&i.value, new) +} + +// Add adds delta to i atomically, returning +// the new updated value. +// +// This operation wraps around in the usual +// two's-complement way. +func (i *Int64) Add(delta int64) int64 { + return Xaddint64(&i.value, delta) +} + +// Uint8 is an atomically accessed uint8 value. +// +// A Uint8 must not be copied. +type Uint8 struct { + noCopy noCopy + value uint8 +} + +// Load accesses and returns the value atomically. +func (u *Uint8) Load() uint8 { + return Load8(&u.value) +} + +// Store updates the value atomically. +func (u *Uint8) Store(value uint8) { + Store8(&u.value, value) +} + +// And takes value and performs a bit-wise +// "and" operation with the value of u, storing +// the result into u. +// +// The full process is performed atomically. +func (u *Uint8) And(value uint8) { + And8(&u.value, value) +} + +// Or takes value and performs a bit-wise +// "or" operation with the value of u, storing +// the result into u. +// +// The full process is performed atomically. +func (u *Uint8) Or(value uint8) { + Or8(&u.value, value) +} + +// Uint32 is an atomically accessed uint32 value. +// +// A Uint32 must not be copied. +type Uint32 struct { + noCopy noCopy + value uint32 +} + +// Load accesses and returns the value atomically. +func (u *Uint32) Load() uint32 { + return Load(&u.value) +} + +// LoadAcquire is a partially unsynchronized version +// of Load that relaxes ordering constraints. Other threads +// may observe operations that precede this operation to +// occur after it, but no operation that occurs after it +// on this thread can be observed to occur before it. +// +// WARNING: Use sparingly and with great care. +func (u *Uint32) LoadAcquire() uint32 { + return LoadAcq(&u.value) +} + +// Store updates the value atomically. +func (u *Uint32) Store(value uint32) { + Store(&u.value, value) +} + +// StoreRelease is a partially unsynchronized version +// of Store that relaxes ordering constraints. Other threads +// may observe operations that occur after this operation to +// precede it, but no operation that precedes it +// on this thread can be observed to occur after it. +// +// WARNING: Use sparingly and with great care. +func (u *Uint32) StoreRelease(value uint32) { + StoreRel(&u.value, value) +} + +// CompareAndSwap atomically compares u's value with old, +// and if they're equal, swaps u's value with new. +// +// Returns true if the operation succeeded. +func (u *Uint32) CompareAndSwap(old, new uint32) bool { + return Cas(&u.value, old, new) +} + +// CompareAndSwapRelease is a partially unsynchronized version +// of Cas that relaxes ordering constraints. Other threads +// may observe operations that occur after this operation to +// precede it, but no operation that precedes it +// on this thread can be observed to occur after it. +// +// Returns true if the operation succeeded. +// +// WARNING: Use sparingly and with great care. +func (u *Uint32) CompareAndSwapRelease(old, new uint32) bool { + return CasRel(&u.value, old, new) +} + +// Swap replaces u's value with new, returning +// u's value before the replacement. +func (u *Uint32) Swap(value uint32) uint32 { + return Xchg(&u.value, value) +} + +// And takes value and performs a bit-wise +// "and" operation with the value of u, storing +// the result into u. +// +// The full process is performed atomically. +func (u *Uint32) And(value uint32) { + And(&u.value, value) +} + +// Or takes value and performs a bit-wise +// "or" operation with the value of u, storing +// the result into u. +// +// The full process is performed atomically. +func (u *Uint32) Or(value uint32) { + Or(&u.value, value) +} + +// Add adds delta to u atomically, returning +// the new updated value. +// +// This operation wraps around in the usual +// two's-complement way. +func (u *Uint32) Add(delta int32) uint32 { + return Xadd(&u.value, delta) +} + +// Uint64 is an atomically accessed uint64 value. +// +// A Uint64 must not be copied. +type Uint64 struct { + noCopy noCopy + value uint64 +} + +// Load accesses and returns the value atomically. +func (u *Uint64) Load() uint64 { + return Load64(&u.value) +} + +// Store updates the value atomically. +func (u *Uint64) Store(value uint64) { + Store64(&u.value, value) +} + +// CompareAndSwap atomically compares u's value with old, +// and if they're equal, swaps u's value with new. +// +// Returns true if the operation succeeded. +func (u *Uint64) CompareAndSwap(old, new uint64) bool { + return Cas64(&u.value, old, new) +} + +// Swap replaces u's value with new, returning +// u's value before the replacement. +func (u *Uint64) Swap(value uint64) uint64 { + return Xchg64(&u.value, value) +} + +// Add adds delta to u atomically, returning +// the new updated value. +// +// This operation wraps around in the usual +// two's-complement way. +func (u *Uint64) Add(delta int64) uint64 { + return Xadd64(&u.value, delta) +} + +// Uintptr is an atomically accessed uintptr value. +// +// A Uintptr must not be copied. +type Uintptr struct { + noCopy noCopy + value uintptr +} + +// Load accesses and returns the value atomically. +func (u *Uintptr) Load() uintptr { + return Loaduintptr(&u.value) +} + +// LoadAcquire is a partially unsynchronized version +// of Load that relaxes ordering constraints. Other threads +// may observe operations that precede this operation to +// occur after it, but no operation that occurs after it +// on this thread can be observed to occur before it. +// +// WARNING: Use sparingly and with great care. +func (u *Uintptr) LoadAcquire() uintptr { + return LoadAcquintptr(&u.value) +} + +// Store updates the value atomically. +func (u *Uintptr) Store(value uintptr) { + Storeuintptr(&u.value, value) +} + +// StoreRelease is a partially unsynchronized version +// of Store that relaxes ordering constraints. Other threads +// may observe operations that occur after this operation to +// precede it, but no operation that precedes it +// on this thread can be observed to occur after it. +// +// WARNING: Use sparingly and with great care. +func (u *Uintptr) StoreRelease(value uintptr) { + StoreReluintptr(&u.value, value) +} + +// CompareAndSwap atomically compares u's value with old, +// and if they're equal, swaps u's value with new. +// +// Returns true if the operation succeeded. +func (u *Uintptr) CompareAndSwap(old, new uintptr) bool { + return Casuintptr(&u.value, old, new) +} + +// Swap replaces u's value with new, returning +// u's value before the replacement. +func (u *Uintptr) Swap(value uintptr) uintptr { + return Xchguintptr(&u.value, value) +} + +// Add adds delta to u atomically, returning +// the new updated value. +// +// This operation wraps around in the usual +// two's-complement way. +func (u *Uintptr) Add(delta uintptr) uintptr { + return Xadduintptr(&u.value, delta) +} + +// Float64 is an atomically accessed float64 value. +// +// A Float64 must not be copied. +type Float64 struct { + u Uint64 +} + +// Load accesses and returns the value atomically. +func (f *Float64) Load() float64 { + r := f.u.Load() + return *(*float64)(unsafe.Pointer(&r)) +} + +// Store updates the value atomically. +func (f *Float64) Store(value float64) { + f.u.Store(*(*uint64)(unsafe.Pointer(&value))) +} + +// UnsafePointer is an atomically accessed unsafe.Pointer value. +// +// Note that because of the atomicity guarantees, stores to values +// of this type never trigger a write barrier, and the relevant +// methods are suffixed with "NoWB" to indicate that explicitly. +// As a result, this type should be used carefully, and sparingly, +// mostly with values that do not live in the Go heap anyway. +// +// An UnsafePointer must not be copied. +type UnsafePointer struct { + noCopy noCopy + value unsafe.Pointer +} + +// Load accesses and returns the value atomically. +func (u *UnsafePointer) Load() unsafe.Pointer { + return Loadp(unsafe.Pointer(&u.value)) +} + +// StoreNoWB updates the value atomically. +// +// WARNING: As the name implies this operation does *not* +// perform a write barrier on value, and so this operation may +// hide pointers from the GC. Use with care and sparingly. +// It is safe to use with values not found in the Go heap. +func (u *UnsafePointer) StoreNoWB(value unsafe.Pointer) { + StorepNoWB(unsafe.Pointer(&u.value), value) +} + +// CompareAndSwapNoWB atomically (with respect to other methods) +// compares u's value with old, and if they're equal, +// swaps u's value with new. +// +// Returns true if the operation succeeded. +// +// WARNING: As the name implies this operation does *not* +// perform a write barrier on value, and so this operation may +// hide pointers from the GC. Use with care and sparingly. +// It is safe to use with values not found in the Go heap. +func (u *UnsafePointer) CompareAndSwapNoWB(old, new unsafe.Pointer) bool { + return Casp1(&u.value, old, new) +} + +// noCopy may be embedded into structs which must not be copied +// after the first use. +// +// See https://golang.org/issues/8005#issuecomment-190753527 +// for details. +type noCopy struct{} + +// Lock is a no-op used by -copylocks checker from `go vet`. +func (*noCopy) Lock() {} +func (*noCopy) Unlock() {} diff --git a/src/runtime/internal/atomic/types_64bit.go b/src/runtime/internal/atomic/types_64bit.go new file mode 100644 index 0000000000..9e5ed68419 --- /dev/null +++ b/src/runtime/internal/atomic/types_64bit.go @@ -0,0 +1,30 @@ +// Copyright 2021 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. + +//go:build amd64 || arm64 || mips64 || mips64le || ppc64 || ppc64le || riscv64 || s390x || wasm +// +build amd64 arm64 mips64 mips64le ppc64 ppc64le riscv64 s390x wasm + +package atomic + +// LoadAcquire is a partially unsynchronized version +// of Load that relaxes ordering constraints. Other threads +// may observe operations that precede this operation to +// occur after it, but no operation that occurs after it +// on this thread can be observed to occur before it. +// +// WARNING: Use sparingly and with great care. +func (u *Uint64) LoadAcquire() uint64 { + return LoadAcq64(&u.value) +} + +// StoreRelease is a partially unsynchronized version +// of Store that relaxes ordering constraints. Other threads +// may observe operations that occur after this operation to +// precede it, but no operation that precedes it +// on this thread can be observed to occur after it. +// +// WARNING: Use sparingly and with great care. +func (u *Uint64) StoreRelease(value uint64) { + StoreRel64(&u.value, value) +}