forked from toolshed/abra
127 lines
3.6 KiB
Go
127 lines
3.6 KiB
Go
// Copyright 2024 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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//go:build race
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package impl
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// When running under race detector, we add a presence map of bytes, that we can access
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// in the hook functions so that we trigger the race detection whenever we have concurrent
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// Read-Writes or Write-Writes. The race detector does not otherwise detect invalid concurrent
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// access to lazy fields as all updates of bitmaps and pointers are done using atomic operations.
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type RaceDetectHookData struct {
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shadowPresence *[]byte
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}
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// Hooks for presence bitmap operations that allocate, read and write the shadowPresence
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// using non-atomic operations.
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func (data *RaceDetectHookData) raceDetectHookAlloc(size presenceSize) {
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sp := make([]byte, size)
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atomicStoreShadowPresence(&data.shadowPresence, &sp)
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}
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func (p presence) raceDetectHookPresent(num uint32) {
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data := p.toRaceDetectData()
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if data == nil {
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return
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}
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sp := atomicLoadShadowPresence(&data.shadowPresence)
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if sp != nil {
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_ = (*sp)[num]
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}
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}
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func (p presence) raceDetectHookSetPresent(num uint32, size presenceSize) {
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data := p.toRaceDetectData()
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if data == nil {
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return
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}
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sp := atomicLoadShadowPresence(&data.shadowPresence)
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if sp == nil {
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data.raceDetectHookAlloc(size)
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sp = atomicLoadShadowPresence(&data.shadowPresence)
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}
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(*sp)[num] = 1
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}
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func (p presence) raceDetectHookClearPresent(num uint32) {
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data := p.toRaceDetectData()
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if data == nil {
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return
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}
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sp := atomicLoadShadowPresence(&data.shadowPresence)
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if sp != nil {
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(*sp)[num] = 0
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}
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}
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// raceDetectHookAllocAndCopy allocates a new shadowPresence slice at lazy and copies
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// shadowPresence bytes from src to lazy.
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func (p presence) raceDetectHookAllocAndCopy(q presence) {
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sData := q.toRaceDetectData()
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dData := p.toRaceDetectData()
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if sData == nil {
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return
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}
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srcSp := atomicLoadShadowPresence(&sData.shadowPresence)
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if srcSp == nil {
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atomicStoreShadowPresence(&dData.shadowPresence, nil)
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return
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}
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n := len(*srcSp)
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dSlice := make([]byte, n)
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atomicStoreShadowPresence(&dData.shadowPresence, &dSlice)
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for i := 0; i < n; i++ {
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dSlice[i] = (*srcSp)[i]
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}
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}
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// raceDetectHookPresent is called by the generated file interface
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// (*proto.internalFuncs) Present to optionally read an unprotected
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// shadow bitmap when race detection is enabled. In regular code it is
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// a noop.
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func raceDetectHookPresent(field *uint32, num uint32) {
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data := findPointerToRaceDetectData(field, num)
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if data == nil {
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return
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}
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sp := atomicLoadShadowPresence(&data.shadowPresence)
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if sp != nil {
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_ = (*sp)[num]
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}
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}
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// raceDetectHookSetPresent is called by the generated file interface
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// (*proto.internalFuncs) SetPresent to optionally write an unprotected
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// shadow bitmap when race detection is enabled. In regular code it is
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// a noop.
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func raceDetectHookSetPresent(field *uint32, num uint32, size presenceSize) {
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data := findPointerToRaceDetectData(field, num)
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if data == nil {
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return
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}
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sp := atomicLoadShadowPresence(&data.shadowPresence)
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if sp == nil {
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data.raceDetectHookAlloc(size)
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sp = atomicLoadShadowPresence(&data.shadowPresence)
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}
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(*sp)[num] = 1
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}
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// raceDetectHookClearPresent is called by the generated file interface
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// (*proto.internalFuncs) ClearPresent to optionally write an unprotected
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// shadow bitmap when race detection is enabled. In regular code it is
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// a noop.
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func raceDetectHookClearPresent(field *uint32, num uint32) {
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data := findPointerToRaceDetectData(field, num)
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if data == nil {
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return
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}
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sp := atomicLoadShadowPresence(&data.shadowPresence)
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if sp != nil {
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(*sp)[num] = 0
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}
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}
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