internal: use bytes.Clone

Change-Id: Ia96ddd520a7bd2fd53bff55315c6fac04ae96a2f
Reviewed-on: https://go-review.googlesource.com/c/go/+/435282
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Auto-Submit: Dmitri Shuralyov <dmitshur@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Run-TryBot: Dmitri Shuralyov <dmitshur@golang.org>

src/internal/coverage/encodemeta/encode.go

@@ -9,6 +9,7 @@ package encodemeta
 // instrumentation is turned on.
 
 import (
+	"bytes"
 	"crypto/md5"
 	"encoding/binary"
 	"fmt"
@@ -82,8 +83,7 @@ func (b *CoverageMetaDataBuilder) AddFunc(f coverage.FuncDesc) uint {
 		lit = 1
 	}
 	b.tmp = uleb128.AppendUleb128(b.tmp, lit)
-	fd.encoded = make([]byte, len(b.tmp))
+	fd.encoded = bytes.Clone(b.tmp)
-	copy(fd.encoded, b.tmp)
 	rv := uint(len(b.funcs))
 	b.funcs = append(b.funcs, fd)
 	return rv

src/internal/fuzz/fuzz.go

@@ -8,6 +8,7 @@
 package fuzz
 
 import (
+	"bytes"
 	"context"
 	"crypto/sha256"
 	"errors"
@@ -775,8 +776,7 @@ func (c *coordinator) peekInput() (fuzzInput, bool) {
 		warmup:  c.warmupRun(),
 	}
 	if c.coverageMask != nil {
-		input.coverageData = make([]byte, len(c.coverageMask))
+		input.coverageData = bytes.Clone(c.coverageMask)
-		copy(input.coverageData, c.coverageMask)
 	}
 	if input.warmup {
 		// No fuzzing will occur, but it should count toward the limit set by

src/internal/fuzz/mem.go

@@ -5,6 +5,7 @@
 package fuzz
 
 import (
+	"bytes"
 	"fmt"
 	"os"
 	"unsafe"
@@ -102,9 +103,7 @@ func (m *sharedMem) valueRef() []byte {
 // valueCopy returns a copy of the value stored in shared memory.
 func (m *sharedMem) valueCopy() []byte {
 	ref := m.valueRef()
-	b := make([]byte, len(ref))
+	return bytes.Clone(ref)
-	copy(b, ref)
-	return b
 }
 
 // setValue copies the data in b into the shared memory buffer and sets