This file is indexed.

/usr/share/go-1.8/test/nowritebarrier.go is in golang-1.8-src 1.8.3-2ubuntu1.

This file is owned by root:root, with mode 0o644.

The actual contents of the file can be viewed below.

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
// errorcheck -+

// Copyright 2016 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.

// Test go:nowritebarrier and related directives.

package p

type t struct {
	f *t
}

var x t
var y *t

//go:nowritebarrier
func a1() {
	x.f = y // ERROR "write barrier prohibited"
	a2()    // no error
}

//go:noinline
func a2() {
	x.f = y
}

//go:nowritebarrierrec
func b1() {
	b2()
}

//go:noinline
func b2() {
	x.f = y // ERROR "write barrier prohibited by caller"
}

// Test recursive cycles through nowritebarrierrec and yeswritebarrierrec.

//go:nowritebarrierrec
func c1() {
	c2()
}

//go:yeswritebarrierrec
func c2() {
	c3()
}

func c3() {
	x.f = y
	c4()
}

//go:nowritebarrierrec
func c4() {
	c2()
}

//go:nowritebarrierrec
func d1() {
	d2()
}

func d2() {
	d3()
}

func d3() {
	x.f = y // ERROR "write barrier prohibited by caller"
	d4()
}

//go:yeswritebarrierrec
func d4() {
	d2()
}