codekingpro/portable-devtools

1// errorcheck -0 -l -d=wb2 3// Copyright 2015 The Go Authors. All rights reserved.4// Use of this source code is governed by a BSD-style5// license that can be found in the LICENSE file.6 7// Test where write barriers are and are not emitted.8 9package p10 11import "unsafe"12 13func f(x **byte, y *byte) {14	*x = y // no barrier (dead store)15 16	z := y // no barrier17	*x = z // ERROR "write barrier"18}19 20func f1(x *[]byte, y []byte) {21	*x = y // no barrier (dead store)22 23	z := y // no barrier24	*x = z // ERROR "write barrier"25}26 27func f1a(x *[]byte, y *[]byte) {28	*x = *y // ERROR "write barrier"29 30	z := *y // no barrier31	*x = z  // ERROR "write barrier"32}33 34func f2(x *interface{}, y interface{}) {35	*x = y // no barrier (dead store)36 37	z := y // no barrier38	*x = z // ERROR "write barrier"39}40 41func f2a(x *interface{}, y *interface{}) {42	*x = *y // no barrier (dead store)43 44	z := y // no barrier45	*x = z // ERROR "write barrier"46}47 48func f3(x *string, y string) {49	*x = y // no barrier (dead store)50 51	z := y // no barrier52	*x = z // ERROR "write barrier"53}54 55func f3a(x *string, y *string) {56	*x = *y // ERROR "write barrier"57 58	z := *y // no barrier59	*x = z  // ERROR "write barrier"60}61 62func f4(x *[2]string, y [2]string) {63	*x = y // ERROR "write barrier"64 65	z := y // no barrier66	*x = z // ERROR "write barrier"67}68 69func f4a(x *[2]string, y *[2]string) {70	*x = *y // ERROR "write barrier"71 72	z := *y // no barrier73	*x = z  // ERROR "write barrier"74}75 76type T struct {77	X *int78	Y int79	M map[int]int80}81 82func f5(t, u *T) {83	t.X = &u.Y // ERROR "write barrier"84}85 86func f6(t *T) {87	t.M = map[int]int{1: 2} // ERROR "write barrier"88}89 90func f7(x, y *int) []*int {91	var z [3]*int92	i := 093	z[i] = x // ERROR "write barrier"94	i++95	z[i] = y // ERROR "write barrier"96	i++97	return z[:i]98}99 100func f9(x *interface{}, v *byte) {101	*x = v // ERROR "write barrier"102}103 104func f10(x *byte, f func(interface{})) {105	f(x)106}107 108func f11(x *unsafe.Pointer, y unsafe.Pointer) {109	*x = unsafe.Pointer(uintptr(y) + 1) // ERROR "write barrier"110}111 112func f12(x []*int, y *int) []*int {113	// write barrier for storing y in x's underlying array114	x = append(x, y) // ERROR "write barrier"115	return x116}117 118func f12a(x []int, y int) []int {119	// y not a pointer, so no write barriers in this function120	x = append(x, y)121	return x122}123 124func f13(x []int, y *[]int) {125	*y = append(x, 1) // ERROR "write barrier"126}127 128func f14(y *[]int) {129	*y = append(*y, 1) // ERROR "write barrier"130}131 132type T1 struct {133	X *int134}135 136func f15(x []T1, y T1) []T1 {137	return append(x, y) // ERROR "write barrier"138}139 140type T8 struct {141	X [8]*int142}143 144func f16(x []T8, y T8) []T8 {145	return append(x, y) // ERROR "write barrier"146}147 148func t1(i interface{}) **int {149	// From issue 14306, make sure we have write barriers in a type switch150	// where the assigned variable escapes.151	switch x := i.(type) {152	case *int: // ERROR "write barrier"153		return &x154	}155	switch y := i.(type) {156	case **int: // no write barrier here157		return y158	}159	return nil160}161 162type T17 struct {163	f func(*T17)164}165 166func f17(x *T17) {167	// Originally from golang.org/issue/13901, but the hybrid168	// barrier requires both to have barriers.169	x.f = f17                      // ERROR "write barrier"170	x.f = func(y *T17) { *y = *x } // ERROR "write barrier"171}172 173type T18 struct {174	a []int175	s string176}177 178func f18(p *T18, x *[]int) {179	p.a = p.a[:5]    // no barrier180	*x = (*x)[0:5]   // no barrier181	p.a = p.a[3:5]   // ERROR "write barrier"182	p.a = p.a[1:2:3] // ERROR "write barrier"183	p.s = p.s[8:9]   // ERROR "write barrier"184	*x = (*x)[3:5]   // ERROR "write barrier"185}186 187func f19(x, y *int, i int) int {188	// Constructing a temporary slice on the stack should not189	// require any write barriers. See issue 14263.190	a := []*int{x, y} // no barrier191	return *a[i]192}193 194func f20(x, y *int, i int) []*int {195	// ... but if that temporary slice escapes, then the196	// write barriers are necessary.197	a := []*int{x, y} // ERROR "write barrier"198	return a199}200 201var x21 *int202var y21 struct {203	x *int204}205var z21 int206 207// f21x: Global -> heap pointer updates must have write barriers.208func f21a(x *int) {209	x21 = x   // ERROR "write barrier"210	y21.x = x // ERROR "write barrier"211}212 213func f21b(x *int) {214	x21 = &z21   // ERROR "write barrier"215	y21.x = &z21 // ERROR "write barrier"216}217 218func f21c(x *int) {219	y21 = struct{ x *int }{x} // ERROR "write barrier"220}221 222func f22(x *int) (y *int) {223	// pointer write on stack should have no write barrier.224	// this is a case that the frontend failed to eliminate.225	p := &y226	*p = x // no barrier227	return228}229 230type T23 struct {231	p *int232	a int233}234 235var t23 T23236var i23 int237 238// f23x: zeroing global needs write barrier for the hybrid barrier.239func f23a() {240	t23 = T23{} // ERROR "write barrier"241}242 243func f23b() {244	// also test partial assignments245	t23 = T23{a: 1} // ERROR "write barrier"246}247 248func f23c() {249	t23 = T23{} // no barrier (dead store)250	// also test partial assignments251	t23 = T23{p: &i23} // ERROR "write barrier"252}253 254var g int255 256func f24() **int {257	p := new(*int)258	*p = &g // no write barrier here259	return p260}261func f25() []string {262	return []string{"abc", "def", "ghi"} // no write barrier here263}264 265type T26 struct {266	a, b, c int267	d, e, f *int268}269 270var g26 int271 272func f26(p *int) *T26 { // see issue 29573273	return &T26{274		a: 5,275		b: 6,276		c: 7,277		d: &g26, // no write barrier: global ptr278		e: nil,  // no write barrier: nil ptr279		f: p,    // ERROR "write barrier"280	}281}282 283func f27(p *int) []interface{} {284	return []interface{}{285		nil,         // no write barrier: zeroed memory, nil ptr286		(*T26)(nil), // no write barrier: zeroed memory, type ptr & nil ptr287		&g26,        // no write barrier: zeroed memory, type ptr & global ptr288		7,           // no write barrier: zeroed memory, type ptr & global ptr289		p,           // ERROR "write barrier"290	}291}292 293var g28 [256]uint64294 295func f28() []interface{} {296	return []interface{}{297		false,      // no write barrier298		true,       // no write barrier299		0,          // no write barrier300		1,          // no write barrier301		uint8(127), // no write barrier302		int8(-4),   // no write barrier303		&g28[5],    // no write barrier304	}305}306