test/escape2.go

// errchk -0 $G -m -l $D/$F.go

// Copyright 2010 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, using compiler diagnostic flags, that the escape analysis is working.
// Compiles but does not run.  Inlining is disabled.

package foo

import (
	"fmt"
	"unsafe"
)

var gxx *int

func foo1(x int) { // ERROR "moved to heap: x"
	gxx = &x // ERROR "&x escapes to heap"
}

func foo2(yy *int) { // ERROR "leaking param: yy"
	gxx = yy
}

func foo3(x int) *int { // ERROR "moved to heap: x"
	return &x // ERROR "&x escapes to heap"
}

type T *T

func foo3b(t T) { // ERROR "leaking param: t"
	*t = t
}

// xx isn't going anywhere, so use of yy is ok
func foo4(xx, yy *int) { // ERROR "xx does not escape" "yy does not escape"
	xx = yy
}

// xx isn't going anywhere, so taking address of yy is ok
func foo5(xx **int, yy *int) { // ERROR "xx does not escape" "yy does not escape"
	xx = &yy // ERROR "&yy does not escape"
}

func foo6(xx **int, yy *int) { // ERROR "xx does not escape" "leaking param: yy"
	*xx = yy
}

func foo7(xx **int, yy *int) { // ERROR "xx does not escape" "yy does not escape"
	**xx = *yy
}

func foo8(xx, yy *int) int { // ERROR "xx does not escape" "yy does not escape"
	xx = yy
	return *xx
}

func foo9(xx, yy *int) *int { // ERROR "leaking param: xx" "leaking param: yy"
	xx = yy
	return xx
}

func foo10(xx, yy *int) { // ERROR "xx does not escape" "yy does not escape"
	*xx = *yy
}

func foo11() int {
	x, y := 0, 42
	xx := &x // ERROR "&x does not escape"
	yy := &y // ERROR "&y does not escape"
	*xx = *yy
	return x
}

var xxx **int

func foo12(yyy **int) { // ERROR "leaking param: yyy"
	xxx = yyy
}

func foo13(yyy **int) { // ERROR "yyy does not escape"
	*xxx = *yyy
}

func foo14(yyy **int) { // ERROR "yyy does not escape"
	**xxx = **yyy
}

func foo15(yy *int) { // ERROR "moved to heap: yy"
	xxx = &yy // ERROR "&yy escapes to heap"
}

func foo16(yy *int) { // ERROR "leaking param: yy"
	*xxx = yy
}

func foo17(yy *int) { // ERROR "yy does not escape"
	**xxx = *yy
}

func foo18(y int) { // ERROR "moved to heap: "y"
	*xxx = &y // ERROR "&y escapes to heap"
}

func foo19(y int) {
	**xxx = y
}

type Bar struct {
	i  int
	ii *int
}

func NewBar() *Bar {
	return &Bar{42, nil} // ERROR "&Bar literal escapes to heap"
}

func NewBarp(x *int) *Bar { // ERROR "leaking param: x"
	return &Bar{42, x} // ERROR "&Bar literal escapes to heap"
}

func NewBarp2(x *int) *Bar { // ERROR "x does not escape"
	return &Bar{*x, nil} // ERROR "&Bar literal escapes to heap"
}

func (b *Bar) NoLeak() int { // ERROR "b does not escape"
	return *(b.ii)
}

func (b *Bar) Leak() *int { // ERROR "leaking param: b"
	return &b.i // ERROR "&b.i escapes to heap"
}

func (b *Bar) AlsoNoLeak() *int { // ERROR "b does not escape"
	return b.ii
}

func (b Bar) AlsoLeak() *int { // ERROR "leaking param: b"
	return b.ii
}

func (b Bar) LeaksToo() *int { // ERROR "leaking param: b"
	v := 0	// ERROR "moved to heap: v"
	b.ii = &v // ERROR "&v escapes"
	return b.ii
}

func (b *Bar) LeaksABit() *int { // ERROR "b does not escape"
	v := 0	// ERROR "moved to heap: v"
	b.ii = &v // ERROR "&v escapes"
	return b.ii
}

func (b Bar) StillNoLeak() int { // ERROR "b does not escape"
	v := 0
	b.ii = &v // ERROR "&v does not escape"
	return b.i
}

func goLeak(b *Bar) { // ERROR "leaking param: b"
	go b.NoLeak()
}

type Bar2 struct {
	i  [12]int
	ii []int
}

func NewBar2() *Bar2 {
	return &Bar2{[12]int{42}, nil} // ERROR "&Bar2 literal escapes to heap"
}

func (b *Bar2) NoLeak() int { // ERROR "b does not escape"
	return b.i[0]
}

func (b *Bar2) Leak() []int { // ERROR "leaking param: b"
	return b.i[:] // ERROR "b.i escapes to heap"
}

func (b *Bar2) AlsoNoLeak() []int { // ERROR "b does not escape"
	return b.ii[0:1]
}

func (b Bar2) AgainNoLeak() [12]int { // ERROR "b does not escape"
	return b.i
}

func (b *Bar2) LeakSelf() { // ERROR "leaking param: b"
	b.ii = b.i[0:4] // ERROR "b.i escapes to heap"
}

func (b *Bar2) LeakSelf2() { // ERROR "leaking param: b"
	var buf []int
	buf = b.i[0:] // ERROR "b.i escapes to heap"
	b.ii = buf
}

func foo21() func() int {
	x := 42             // ERROR "moved to heap: x"
	return func() int { // ERROR "func literal escapes to heap"
		return x // ERROR "&x escapes to heap"
	}
}

func foo22() int {
	x := 42
	return func() int { // ERROR "func literal does not escape"
		return x
	}()
}

func foo23(x int) func() int { // ERROR "moved to heap: x"
	return func() int { // ERROR "func literal escapes to heap"
		return x // ERROR "&x escapes to heap"
	}
}

func foo23a(x int) func() int { // ERROR "moved to heap: x"
	f := func() int { // ERROR "func literal escapes to heap"
		return x // ERROR "&x escapes to heap"
	}
	return f
}

func foo23b(x int) *(func() int) { // ERROR "moved to heap: x"
	f := func() int { return x } // ERROR "moved to heap: f" "func literal escapes to heap" "&x escapes to heap"
	return &f                    // ERROR "&f escapes to heap"
}

func foo24(x int) int {
	return func() int { // ERROR "func literal does not escape"
		return x
	}()
}

var x *int

func fooleak(xx *int) int { // ERROR "leaking param: xx"
	x = xx
	return *x
}

func foonoleak(xx *int) int { // ERROR "xx does not escape"
	return *x + *xx
}

func foo31(x int) int { // ERROR "moved to heap: x"
	return fooleak(&x) // ERROR "&x escapes to heap"
}

func foo32(x int) int {
	return foonoleak(&x) // ERROR "&x does not escape"
}

type Foo struct {
	xx *int
	x  int
}

var F Foo
var pf *Foo

func (f *Foo) fooleak() { // ERROR "leaking param: f"
	pf = f
}

func (f *Foo) foonoleak() { // ERROR "f does not escape"
	F.x = f.x
}

func (f *Foo) Leak() { // ERROR "leaking param: f"
	f.fooleak()
}

func (f *Foo) NoLeak() { // ERROR "f does not escape"
	f.foonoleak()
}

func foo41(x int) { // ERROR "moved to heap: x"
	F.xx = &x // ERROR "&x escapes to heap"
}

func (f *Foo) foo42(x int) { // ERROR "f does not escape" "moved to heap: x"
	f.xx = &x // ERROR "&x escapes to heap"
}

func foo43(f *Foo, x int) { // ERROR "f does not escape" "moved to heap: x"
	f.xx = &x // ERROR "&x escapes to heap"
}

func foo44(yy *int) { // ERROR "leaking param: yy"
	F.xx = yy
}

func (f *Foo) foo45() { // ERROR "f does not escape"
	F.x = f.x
}

func (f *Foo) foo46() { // ERROR "f does not escape"
	F.xx = f.xx
}

func (f *Foo) foo47() { // ERROR "leaking param: f"
	f.xx = &f.x // ERROR "&f.x escapes to heap"
}

var ptrSlice []*int

func foo50(i *int) { // ERROR "leaking param: i"
	ptrSlice[0] = i
}

var ptrMap map[*int]*int

func foo51(i *int) { // ERROR "leaking param: i"
	ptrMap[i] = i
}

func indaddr1(x int) *int { // ERROR "moved to heap: x"
	return &x // ERROR "&x escapes to heap"
}

func indaddr2(x *int) *int { // ERROR "leaking param: x"
	return *&x // ERROR "&x does not escape"
}

func indaddr3(x *int32) *int { // ERROR "leaking param: x"
	return *(**int)(unsafe.Pointer(&x)) // ERROR "&x does not escape"
}

// From package math:

func Float32bits(f float32) uint32 {
	return *(*uint32)(unsafe.Pointer(&f)) // ERROR "&f does not escape"
}

func Float32frombits(b uint32) float32 {
	return *(*float32)(unsafe.Pointer(&b)) // ERROR "&b does not escape"
}

func Float64bits(f float64) uint64 {
	return *(*uint64)(unsafe.Pointer(&f)) // ERROR "&f does not escape"
}

func Float64frombits(b uint64) float64 {
	return *(*float64)(unsafe.Pointer(&b)) // ERROR "&b does not escape"
}

// contrast with
func float64bitsptr(f float64) *uint64 { // ERROR "moved to heap: f"
	return (*uint64)(unsafe.Pointer(&f)) // ERROR "&f escapes to heap"
}

func float64ptrbitsptr(f *float64) *uint64 { // ERROR "leaking param: f"
	return (*uint64)(unsafe.Pointer(f))
}

func typesw(i interface{}) *int { // ERROR "leaking param: i"
	switch val := i.(type) {
	case *int:
		return val
	case *int8:
		v := int(*val) // ERROR "moved to heap: v"
		return &v      // ERROR "&v escapes to heap"
	}
	return nil
}

func exprsw(i *int) *int { // ERROR "leaking param: i"
	switch j := i; *j + 110 {
	case 12:
		return j
	case 42:
		return nil
	}
	return nil

}

// assigning to an array element is like assigning to the array
func foo60(i *int) *int { // ERROR "leaking param: i"
	var a [12]*int
	a[0] = i
	return a[1]
}

func foo60a(i *int) *int { // ERROR "i does not escape"
	var a [12]*int
	a[0] = i
	return nil
}

// assigning to a struct field  is like assigning to the struct
func foo61(i *int) *int { // ERROR "leaking param: i"
	type S struct {
		a, b *int
	}
	var s S
	s.a = i
	return s.b
}

func foo61a(i *int) *int { // ERROR "i does not escape"
	type S struct {
		a, b *int
	}
	var s S
	s.a = i
	return nil
}

// assigning to a struct field is like assigning to the struct but
// here this subtlety is lost, since s.a counts as an assignment to a
// track-losing dereference.
func foo62(i *int) *int { // ERROR "leaking param: i"
	type S struct {
		a, b *int
	}
	s := new(S) // ERROR "new[(]S[)] does not escape"
	s.a = i
	return nil // s.b
}

type M interface {
	M()
}

func foo63(m M) { // ERROR "m does not escape"
}

func foo64(m M) { // ERROR "leaking param: m"
	m.M()
}

func foo64b(m M) { // ERROR "leaking param: m"
	defer m.M()
}

type MV int

func (MV) M() {}

func foo65() {
	var mv MV
	foo63(&mv) // ERROR "&mv does not escape"
}

func foo66() {
	var mv MV  // ERROR "moved to heap: mv"
	foo64(&mv) // ERROR "&mv escapes to heap"
}

func foo67() {
	var mv MV
	foo63(mv)
}

func foo68() {
	var mv MV
	foo64(mv) // escapes but it's an int so irrelevant
}

func foo69(m M) { // ERROR "leaking param: m"
	foo64(m)
}

func foo70(mv1 *MV, m M) { // ERROR "leaking param: mv1" "leaking param: m"
	m = mv1
	foo64(m)
}

func foo71(x *int) []*int { // ERROR "leaking param: x"
	var y []*int
	y = append(y, x)
	return y
}

func foo71a(x int) []*int { // ERROR "moved to heap: x"
	var y []*int
	y = append(y, &x) // ERROR "&x escapes to heap"
	return y
}

func foo72() {
	var x int
	var y [1]*int
	y[0] = &x // ERROR "&x does not escape"
}

func foo72aa() [10]*int {
	var x int // ERROR "moved to heap: x"
	var y [10]*int
	y[0] = &x // ERROR "&x escapes to heap"
	return y
}

func foo72a() {
	var y [10]*int
	for i := 0; i < 10; i++ {
		// escapes its scope
		x := i    // ERROR "moved to heap: x"
		y[i] = &x // ERROR "&x escapes to heap"
	}
	return
}

func foo72b() [10]*int {
	var y [10]*int
	for i := 0; i < 10; i++ {
		x := i    // ERROR "moved to heap: x"
		y[i] = &x // ERROR "&x escapes to heap"
	}
	return y
}

// issue 2145
func foo73() {
	s := []int{3, 2, 1} // ERROR "\[\]int literal does not escape"
	for _, v := range s {
		vv := v // ERROR "moved to heap: vv"
		// actually just escapes its scope
		defer func() { // ERROR "func literal escapes to heap"
			println(vv) // ERROR "&vv escapes to heap"
		}()
	}
}

func foo74() {
	s := []int{3, 2, 1} // ERROR "\[\]int literal does not escape"
	for _, v := range s {
		vv := v // ERROR "moved to heap: vv"
		// actually just escapes its scope
		fn := func() { // ERROR "func literal escapes to heap"
			println(vv) // ERROR "&vv escapes to heap"
		}
		defer fn()
	}
}

func myprint(y *int, x ...interface{}) *int { // ERROR "x does not escape" "leaking param: y"
	return y
}

func myprint1(y *int, x ...interface{}) *interface{} { // ERROR "y does not escape" "leaking param: x"
	return &x[0] // ERROR "&x.0. escapes to heap"
}

func foo75(z *int) { // ERROR "leaking param: z"
	myprint(z, 1, 2, 3) // ERROR "[.][.][.] argument does not escape"
}

func foo75a(z *int) { // ERROR "z does not escape"
	myprint1(z, 1, 2, 3) // ERROR "[.][.][.] argument escapes to heap"
}

func foo76(z *int) { // ERROR "leaking param: z"
	myprint(nil, z) // ERROR "[.][.][.] argument does not escape"
}

func foo76a(z *int) { // ERROR "leaking param: z"
	myprint1(nil, z) // ERROR "[.][.][.] argument escapes to heap"
}

func foo76b() {
	myprint(nil, 1, 2, 3) // ERROR "[.][.][.] argument does not escape"
}

func foo76c() {
	myprint1(nil, 1, 2, 3) // ERROR "[.][.][.] argument escapes to heap"
}

func foo76d() {
	defer myprint(nil, 1, 2, 3) // ERROR "[.][.][.] argument does not escape"
}

func foo76e() {
	defer myprint1(nil, 1, 2, 3) // ERROR "[.][.][.] argument escapes to heap"
}

func foo76f() {
	for {
		// TODO: This one really only escapes its scope, but we don't distinguish yet.
		defer myprint(nil, 1, 2, 3) // ERROR "[.][.][.] argument escapes to heap"
	}
}

func foo76g() {
	for {
		defer myprint1(nil, 1, 2, 3) // ERROR "[.][.][.] argument escapes to heap"
	}
}

func foo77(z []interface{}) { // ERROR "z does not escape"
	myprint(nil, z...) // z does not escape
}

func foo77a(z []interface{}) { // ERROR "leaking param: z"
	myprint1(nil, z...)
}

func foo78(z int) *int { // ERROR "moved to heap: z"
	return &z // ERROR "&z escapes to heap"
}

func foo78a(z int) *int { // ERROR "moved to heap: z"
	y := &z   // ERROR "&z escapes to heap"
	x := &y   // ERROR "&y does not escape"
	return *x // really return y
}

func foo79() *int {
	return new(int) // ERROR "new[(]int[)] escapes to heap"
}

func foo80() *int {
	var z *int
	for {
		// Really just escapes its scope but we don't distinguish
		z = new(int) // ERROR "new[(]int[)] escapes to heap"
	}
	_ = z
	return nil
}

func foo81() *int {
	for {
		z := new(int) // ERROR "new[(]int[)] does not escape"
		_ = z
	}
	return nil
}

type Fooer interface {
	Foo()
}

type LimitedFooer struct {
	Fooer
	N int64
}

func LimitFooer(r Fooer, n int64) Fooer { // ERROR "leaking param: r"
	return &LimitedFooer{r, n} // ERROR "&LimitedFooer literal escapes to heap"
}

func foo90(x *int) map[*int]*int { // ERROR "leaking param: x"
	return map[*int]*int{nil: x} // ERROR "map\[\*int\]\*int literal escapes to heap"
}

func foo91(x *int) map[*int]*int { // ERROR "leaking param: x"
	return map[*int]*int{x: nil} // ERROR "map\[\*int\]\*int literal escapes to heap"
}

func foo92(x *int) [2]*int { // ERROR "leaking param: x"
	return [2]*int{x, nil}
}

// does not leak c
func foo93(c chan *int) *int { // ERROR "c does not escape"
	for v := range c {
		return v
	}
	return nil
}

// does not leak m
func foo94(m map[*int]*int, b bool) *int { // ERROR "m does not escape"
	for k, v := range m {
		if b {
			return k
		}
		return v
	}
	return nil
}

// does leak x
func foo95(m map[*int]*int, x *int) { // ERROR "m does not escape" "leaking param: x"
	m[x] = x
}

// does not leak m
func foo96(m []*int) *int { // ERROR "m does not escape"
	return m[0]
}

// does leak m
func foo97(m [1]*int) *int { // ERROR "leaking param: m"
	return m[0]
}

// does not leak m
func foo98(m map[int]*int) *int { // ERROR "m does not escape"
	return m[0]
}

// does leak m
func foo99(m *[1]*int) []*int { // ERROR "leaking param: m"
	return m[:]
}

// does not leak m
func foo100(m []*int) *int { // ERROR "m does not escape"
	for _, v := range m {
		return v
	}
	return nil
}

// does leak m
func foo101(m [1]*int) *int { // ERROR "leaking param: m"
	for _, v := range m {
		return v
	}
	return nil
}

// does not leak m
func foo101a(m [1]*int) *int { // ERROR "m does not escape"
	for i := range m { // ERROR "moved to heap: i"
		return &i // ERROR "&i escapes to heap"
	}
	return nil
}

// does leak x
func foo102(m []*int, x *int) { // ERROR "m does not escape" "leaking param: x"
	m[0] = x
}

// does not leak x
func foo103(m [1]*int, x *int) { // ERROR "m does not escape" "x does not escape"
	m[0] = x
}

var y []*int

// does not leak x
func foo104(x []*int) { // ERROR "x does not escape"
	copy(y, x)
}

// does not leak x
func foo105(x []*int) { // ERROR "x does not escape"
	_ = append(y, x...)
}

// does leak x
func foo106(x *int) { // ERROR "leaking param: x"
	_ = append(y, x)
}

func foo107(x *int) map[*int]*int { // ERROR "leaking param: x"
	return map[*int]*int{x: nil} // ERROR "map.* literal escapes to heap"
}

func foo108(x *int) map[*int]*int { // ERROR "leaking param: x"
	return map[*int]*int{nil: x} // ERROR "map.* literal escapes to heap"
}

func foo109(x *int) *int { // ERROR "leaking param: x"
	m := map[*int]*int{x: nil} // ERROR "map.* literal does not escape"
	for k, _ := range m {
		return k
	}
	return nil
}

func foo110(x *int) *int { // ERROR "leaking param: x"
	m := map[*int]*int{nil: x} // ERROR "map.* literal does not escape"
	return m[nil]
}

func foo111(x *int) *int { // ERROR "leaking param: x"
	m := []*int{x} // ERROR "\[\]\*int literal does not escape"
	return m[0]
}

func foo112(x *int) *int { // ERROR "leaking param: x"
	m := [1]*int{x}
	return m[0]
}

func foo113(x *int) *int { // ERROR "leaking param: x"
	m := Bar{ii: x}
	return m.ii
}

func foo114(x *int) *int { // ERROR "leaking param: x"
	m := &Bar{ii: x} // ERROR "&Bar literal does not escape"
	return m.ii
}

func foo115(x *int) *int { // ERROR "leaking param: x"
	return (*int)(unsafe.Pointer(uintptr(unsafe.Pointer(x)) + 1))
}

func foo116(b bool) *int {
	if b {
		x := 1    // ERROR "moved to heap: x"
		return &x // ERROR "&x escapes to heap"
	} else {
		y := 1    // ERROR "moved to heap: y"
		return &y // ERROR "&y escapes to heap"
	}
	return nil
}

func foo117(unknown func(interface{})) { // ERROR "unknown does not escape"
	x := 1      // ERROR "moved to heap: x"
	unknown(&x) // ERROR "&x escapes to heap"
}

func foo118(unknown func(*int)) { // ERROR "unknown does not escape"
	x := 1      // ERROR "moved to heap: x"
	unknown(&x) // ERROR "&x escapes to heap"
}

func external(*int)

func foo119(x *int) { // ERROR "leaking param: x"
	external(x)
}

func foo120() {
	// formerly exponential time analysis
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	// use the labels to silence compiler errors
	goto L1
	goto L2
	goto L3
	goto L4
	goto L5
	goto L6
	goto L7
	goto L8
	goto L9
	goto L10
	goto L11
	goto L12
	goto L13
	goto L14
	goto L15
	goto L16
	goto L17
	goto L18
	goto L19
	goto L20
	goto L21
	goto L22
	goto L23
	goto L24
	goto L25
	goto L26
	goto L27
	goto L28
	goto L29
	goto L30
	goto L31
	goto L32
	goto L33
	goto L34
	goto L35
	goto L36
	goto L37
	goto L38
	goto L39
	goto L40
	goto L41
	goto L42
	goto L43
	goto L44
	goto L45
	goto L46
	goto L47
	goto L48
	goto L49
	goto L50
	goto L51
	goto L52
	goto L53
	goto L54
	goto L55
	goto L56
	goto L57
	goto L58
	goto L59
	goto L60
	goto L61
	goto L62
	goto L63
	goto L64
	goto L65
	goto L66
	goto L67
	goto L68
	goto L69
	goto L70
	goto L71
	goto L72
	goto L73
	goto L74
	goto L75
	goto L76
	goto L77
	goto L78
	goto L79
	goto L80
	goto L81
	goto L82
	goto L83
	goto L84
	goto L85
	goto L86
	goto L87
	goto L88
	goto L89
	goto L90
	goto L91
	goto L92
	goto L93
	goto L94
	goto L95
	goto L96
	goto L97
	goto L98
	goto L99
	goto L100
}

func foo121() {
	for i := 0; i < 10; i++ {
		defer myprint(nil, i) // ERROR "[.][.][.] argument escapes to heap"
		go myprint(nil, i)    // ERROR "[.][.][.] argument escapes to heap"
	}
}

// same as foo121 but check across import
func foo121b() {
	for i := 0; i < 10; i++ {
		defer fmt.Printf("%d", i) // ERROR "[.][.][.] argument escapes to heap"
		go fmt.Printf("%d", i)    // ERROR "[.][.][.] argument escapes to heap"
	}
}

// a harmless forward jump
func foo122() {
	var i *int

	goto L1
L1:
	i = new(int) // ERROR "does not escape"
	_ = i
}

// a backward jump, increases loopdepth
func foo123() {
	var i *int

L1:
	i = new(int) // ERROR "escapes"

	goto L1
	_ = i
}