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go/test/escape5.go
Russ Cox 71282131a1 cmd/gc: fix escape analysis bug
The code assumed that the only choices were EscNone, EscScope, and EscHeap,
so that it makes sense to set EscScope only if the current setting is EscNone.
Now that we have the many variants of EscReturn, this logic is false, and it was
causing important EscScopes to be ignored in favor of EscReturn.

Fixes #4360.

R=ken2
CC=golang-dev, lvd
https://golang.org/cl/6816103
2012-11-07 15:15:21 -05:00

145 lines
3.2 KiB
Go

// 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
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 .anon1" "leaking param: p to result .anon2"
return p, p
}
func leaktoret22(p, q *int) (*int, *int) { // ERROR "leaking param: p to result .anon2" "leaking param: q to result .anon3"
return p, q
}
func leaktoret22b(p, q *int) (*int, *int) { // ERROR "leaking param: p to result .anon3" "leaking param: q to result .anon2"
return leaktoret22(q, p)
}
func leaktoret22c(p, q *int) (*int, *int) { // ERROR "leaking param: p to result .anon3" "leaking param: q to result .anon2"
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) // ERROR "&x does not escape"
_ = p
}
func f2() {
var x int
p := leaktoret(&x) // ERROR "&x does not escape"
_ = p
}
func f3() {
var x int // ERROR "moved to heap: x"
p := leaktoret(&x) // ERROR "&x escapes to heap"
gp = p
}
func f4() {
var x int // ERROR "moved to heap: x"
p, q := leaktoret2(&x) // ERROR "&x escapes to heap"
gp = p
gp = q
}
func f5() {
var x int
leaktoret22(leaktoret2(&x)) // ERROR "&x does not escape"
}
func f6() {
var x int // ERROR "moved to heap: x"
px1, px2 := leaktoret22(leaktoret2(&x)) // ERROR "&x escapes to heap"
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 to result k" "leaking param: p"
if p == nil {
k = T2{}
return
}
global = p // should make p leak always
return T2{p}
}
func f9() {
var j T1 // ERROR "moved to heap: j"
f8(&j) // ERROR "&j escapes to heap"
}