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2c98915ac7
When GODEBUG=fuzzdebug=1, log additional debug level information about what the fuzzer is doing. This provides useful information for investigating the operation and performance of the fuzzing engine, and is necessary for profiling new fuzzing strategies. Change-Id: Ic3e24e7a128781377e62785767a218811c3c2030 Reviewed-on: https://go-review.googlesource.com/c/go/+/324972 Trust: Roland Shoemaker <roland@golang.org> Trust: Katie Hockman <katie@golang.org> Run-TryBot: Roland Shoemaker <roland@golang.org> TryBot-Result: Go Bot <gobot@golang.org> Reviewed-by: Katie Hockman <katie@golang.org>
63 lines
1.6 KiB
Go
63 lines
1.6 KiB
Go
// Copyright 2021 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 fuzz
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import (
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"internal/unsafeheader"
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"unsafe"
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)
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// coverage returns a []byte containing unique 8-bit counters for each edge of
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// the instrumented source code. This coverage data will only be generated if
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// `-d=libfuzzer` is set at build time. This can be used to understand the code
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// coverage of a test execution.
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func coverage() []byte {
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addr := unsafe.Pointer(&_counters)
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size := uintptr(unsafe.Pointer(&_ecounters)) - uintptr(addr)
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var res []byte
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*(*unsafeheader.Slice)(unsafe.Pointer(&res)) = unsafeheader.Slice{
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Data: addr,
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Len: int(size),
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Cap: int(size),
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}
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return res
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}
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// ResetCovereage sets all of the counters for each edge of the instrumented
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// source code to 0.
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func ResetCoverage() {
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cov := coverage()
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for i := range cov {
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cov[i] = 0
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}
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}
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// SnapshotCoverage copies the current counter values into coverageSnapshot,
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// preserving them for later inspection.
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func SnapshotCoverage() {
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cov := coverage()
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if coverageSnapshot == nil {
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coverageSnapshot = make([]byte, len(cov))
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}
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copy(coverageSnapshot, cov)
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}
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func countEdges(cov []byte) int {
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n := 0
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for _, c := range cov {
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if c > 0 {
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n++
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}
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}
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return n
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}
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var coverageSnapshot []byte
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// _counters and _ecounters mark the start and end, respectively, of where
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// the 8-bit coverage counters reside in memory. They're known to cmd/link,
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// which specially assigns their addresses for this purpose.
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var _counters, _ecounters [0]byte
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