Initial commit: Go 1.23 release state

test/escape5.go

@@ -0,0 +1,281 @@
+// errorcheck -0 -m -l
+
+// Copyright 2012 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 (
+	"runtime"
+	"unsafe"
+)
+
+func noleak(p *int) int { // ERROR "p does not escape"
+	return *p
+}
+
+func leaktoret(p *int) *int { // ERROR "leaking param: p to result"
+	return p
+}
+
+func leaktoret2(p *int) (*int, *int) { // ERROR "leaking param: p to result ~r0" "leaking param: p to result ~r1"
+	return p, p
+}
+
+func leaktoret22(p, q *int) (*int, *int) { // ERROR "leaking param: p to result ~r0" "leaking param: q to result ~r1"
+	return p, q
+}
+
+func leaktoret22b(p, q *int) (*int, *int) { // ERROR "leaking param: p to result ~r1" "leaking param: q to result ~r0"
+	return leaktoret22(q, p)
+}
+
+func leaktoret22c(p, q *int) (*int, *int) { // ERROR "leaking param: p to result ~r1" "leaking param: q to result ~r0"
+	r, s := leaktoret22(q, p)
+	return r, s
+}
+
+func leaktoret22d(p, q *int) (r, s *int) { // ERROR "leaking param: p to result s" "leaking param: q to result r"
+	r, s = leaktoret22(q, p)
+	return
+}
+
+func leaktoret22e(p, q *int) (r, s *int) { // ERROR "leaking param: p to result s" "leaking param: q to result r"
+	r, s = leaktoret22(q, p)
+	return r, s
+}
+
+func leaktoret22f(p, q *int) (r, s *int) { // ERROR "leaking param: p to result s" "leaking param: q to result r"
+	rr, ss := leaktoret22(q, p)
+	return rr, ss
+}
+
+var gp *int
+
+func leaktosink(p *int) *int { // ERROR "leaking param: p"
+	gp = p
+	return p
+}
+
+func f1() {
+	var x int
+	p := noleak(&x)
+	_ = p
+}
+
+func f2() {
+	var x int
+	p := leaktoret(&x)
+	_ = p
+}
+
+func f3() {
+	var x int // ERROR "moved to heap: x"
+	p := leaktoret(&x)
+	gp = p
+}
+
+func f4() {
+	var x int // ERROR "moved to heap: x"
+	p, q := leaktoret2(&x)
+	gp = p
+	gp = q
+}
+
+func f5() {
+	var x int
+	leaktoret22(leaktoret2(&x))
+}
+
+func f6() {
+	var x int // ERROR "moved to heap: x"
+	px1, px2 := leaktoret22(leaktoret2(&x))
+	gp = px1
+	_ = px2
+}
+
+type T struct{ x int }
+
+func (t *T) Foo(u int) (*T, bool) { // ERROR "leaking param: t to result"
+	t.x += u
+	return t, true
+}
+
+func f7() *T {
+	r, _ := new(T).Foo(42) // ERROR "new.T. escapes to heap"
+	return r
+}
+
+func leakrecursive1(p, q *int) (*int, *int) { // ERROR "leaking param: p" "leaking param: q"
+	return leakrecursive2(q, p)
+}
+
+func leakrecursive2(p, q *int) (*int, *int) { // ERROR "leaking param: p" "leaking param: q"
+	if *p > *q {
+		return leakrecursive1(q, p)
+	}
+	// without this, leakrecursive? are safe for p and q, b/c in fact their graph does not have leaking edges.
+	return p, q
+}
+
+var global interface{}
+
+type T1 struct {
+	X *int
+}
+
+type T2 struct {
+	Y *T1
+}
+
+func f8(p *T1) (k T2) { // ERROR "leaking param: p$"
+	if p == nil {
+		k = T2{}
+		return
+	}
+
+	// should make p leak always
+	global = p
+	return T2{p}
+}
+
+func f9() {
+	var j T1 // ERROR "moved to heap: j"
+	f8(&j)
+}
+
+func f10() {
+	// These don't escape but are too big for the stack
+	var x [1 << 30]byte         // ERROR "moved to heap: x"
+	var y = make([]byte, 1<<30) // ERROR "make\(\[\]byte, 1073741824\) escapes to heap"
+	_ = x[0] + y[0]
+}
+
+// Test for issue 19687 (passing to unnamed parameters does not escape).
+func f11(**int) {
+}
+func f12(_ **int) {
+}
+func f13() {
+	var x *int
+	f11(&x)
+	f12(&x)
+	runtime.KeepAlive(&x)
+}
+
+// Test for issue 24305 (passing to unnamed receivers does not escape).
+type U int
+
+func (*U) M()   {}
+func (_ *U) N() {}
+
+func fbad24305a() {
+	var u U
+	u.M()
+	u.N()
+}
+
+func fbad24305b() {
+	var u U
+	(*U).M(&u)
+	(*U).N(&u)
+}
+
+// Issue 24730: taking address in a loop causes unnecessary escape
+type T24730 struct {
+	x [64]byte
+}
+
+func (t *T24730) g() { // ERROR "t does not escape"
+	y := t.x[:]
+	for i := range t.x[:] {
+		y = t.x[:]
+		y[i] = 1
+	}
+
+	var z *byte
+	for i := range t.x[:] {
+		z = &t.x[i]
+		*z = 2
+	}
+}
+
+// Issue 15730: copy causes unnecessary escape
+
+var sink []byte
+var sink2 []int
+var sink3 []*int
+
+func f15730a(args ...interface{}) { // ERROR "args does not escape"
+	for _, arg := range args {
+		switch a := arg.(type) {
+		case string:
+			copy(sink, a)
+		}
+	}
+}
+
+func f15730b(args ...interface{}) { // ERROR "args does not escape"
+	for _, arg := range args {
+		switch a := arg.(type) {
+		case []int:
+			copy(sink2, a)
+		}
+	}
+}
+
+func f15730c(args ...interface{}) { // ERROR "leaking param content: args"
+	for _, arg := range args {
+		switch a := arg.(type) {
+		case []*int:
+			// copy pointerful data should cause escape
+			copy(sink3, a)
+		}
+	}
+}
+
+// Issue 29000: unnamed parameter is not handled correctly
+
+var sink4 interface{}
+var alwaysFalse = false
+
+func f29000(_ int, x interface{}) { // ERROR "leaking param: x"
+	sink4 = x
+	if alwaysFalse {
+		g29000()
+	}
+}
+
+func g29000() {
+	x := 1
+	f29000(2, x) // ERROR "x escapes to heap"
+}
+
+// Issue 28369: taking an address of a parameter and converting it into a uintptr causes an
+// unnecessary escape.
+
+var sink28369 uintptr
+
+func f28369(n int) int {
+	if n == 0 {
+		sink28369 = uintptr(unsafe.Pointer(&n))
+		return n
+	}
+
+	return 1 + f28369(n-1)
+}
+
+// Issue 44614: parameters that flow to a heap-allocated result
+// parameter must be recorded as a heap-flow rather than a
+// result-flow.
+
+// N.B., must match "leaking param: p",
+// but *not* "leaking param: p to result r level=0".
+func f(p *int) (r *int) { // ERROR "leaking param: p$" "moved to heap: r"
+	sink4 = &r
+	return p
+}