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https://github.com/golang/go
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a069cf048d
Before, an unnamed return value turned into an ONAME node n with n->sym named ~anon%d, and n->orig == n. A blank-named return value turned into an ONAME node n with n->sym named ~anon%d but n->orig == the original blank n. Code generation and printing uses n->orig, so that this node formatted as _. But some code does not use n->orig. In particular the liveness code does not know about the n->orig convention and so mishandles blank identifiers. It is possible to fix but seemed better to avoid the confusion entirely. Now the first kind of node is named ~r%d and the second ~b%d; both have n->orig == n, so that it doesn't matter whether code uses n or n->orig. After this change the ->orig field is only used for other kinds of expressions, not for ONAME nodes. This requires distinguishing ~b from ~r names in a few places that care. It fixes a liveness analysis bug without actually changing the liveness code. TBR=ken2 CC=golang-codereviews https://golang.org/cl/63630043
152 lines
3.4 KiB
Go
152 lines
3.4 KiB
Go
// errorcheck -0 -m -l
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// Copyright 2012 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// Test, using compiler diagnostic flags, that the escape analysis is working.
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// Compiles but does not run. Inlining is disabled.
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package foo
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func noleak(p *int) int { // ERROR "p does not escape"
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return *p
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}
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func leaktoret(p *int) *int { // ERROR "leaking param: p to result"
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return p
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}
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func leaktoret2(p *int) (*int, *int) { // ERROR "leaking param: p to result ~r1" "leaking param: p to result ~r2"
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return p, p
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}
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func leaktoret22(p, q *int) (*int, *int) { // ERROR "leaking param: p to result ~r2" "leaking param: q to result ~r3"
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return p, q
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}
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func leaktoret22b(p, q *int) (*int, *int) { // ERROR "leaking param: p to result ~r3" "leaking param: q to result ~r2"
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return leaktoret22(q, p)
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}
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func leaktoret22c(p, q *int) (*int, *int) { // ERROR "leaking param: p to result ~r3" "leaking param: q to result ~r2"
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r, s := leaktoret22(q, p)
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return r, s
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}
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func leaktoret22d(p, q *int) (r, s *int) { // ERROR "leaking param: p to result s" "leaking param: q to result r"
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r, s = leaktoret22(q, p)
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return
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}
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func leaktoret22e(p, q *int) (r, s *int) { // ERROR "leaking param: p to result s" "leaking param: q to result r"
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r, s = leaktoret22(q, p)
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return r, s
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}
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func leaktoret22f(p, q *int) (r, s *int) { // ERROR "leaking param: p to result s" "leaking param: q to result r"
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rr, ss := leaktoret22(q, p)
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return rr, ss
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}
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var gp *int
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func leaktosink(p *int) *int { // ERROR "leaking param: p"
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gp = p
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return p
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}
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func f1() {
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var x int
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p := noleak(&x) // ERROR "&x does not escape"
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_ = p
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}
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func f2() {
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var x int
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p := leaktoret(&x) // ERROR "&x does not escape"
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_ = p
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}
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func f3() {
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var x int // ERROR "moved to heap: x"
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p := leaktoret(&x) // ERROR "&x escapes to heap"
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gp = p
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}
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func f4() {
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var x int // ERROR "moved to heap: x"
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p, q := leaktoret2(&x) // ERROR "&x escapes to heap"
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gp = p
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gp = q
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}
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func f5() {
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var x int
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leaktoret22(leaktoret2(&x)) // ERROR "&x does not escape"
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}
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func f6() {
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var x int // ERROR "moved to heap: x"
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px1, px2 := leaktoret22(leaktoret2(&x)) // ERROR "&x escapes to heap"
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gp = px1
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_ = px2
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}
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type T struct{ x int }
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func (t *T) Foo(u int) (*T, bool) { // ERROR "leaking param: t to result"
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t.x += u
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return t, true
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}
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func f7() *T {
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r, _ := new(T).Foo(42) // ERROR "new.T. escapes to heap"
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return r
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}
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func leakrecursive1(p, q *int) (*int, *int) { // ERROR "leaking param: p" "leaking param: q"
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return leakrecursive2(q, p)
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}
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func leakrecursive2(p, q *int) (*int, *int) { // ERROR "leaking param: p" "leaking param: q"
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if *p > *q {
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return leakrecursive1(q, p)
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}
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// without this, leakrecursive? are safe for p and q, b/c in fact their graph does not have leaking edges.
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return p, q
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}
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var global interface{}
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type T1 struct {
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X *int
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}
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type T2 struct {
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Y *T1
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}
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func f8(p *T1) (k T2) { // ERROR "leaking param: p to result k" "leaking param: p"
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if p == nil {
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k = T2{}
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return
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}
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global = p // should make p leak always
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return T2{p}
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}
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func f9() {
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var j T1 // ERROR "moved to heap: j"
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f8(&j) // ERROR "&j escapes to heap"
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}
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func f10() {
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// These don't escape but are too big for the stack
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var x [1<<30]byte // ERROR "moved to heap: x"
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var y = make([]byte, 1<<30) // ERROR "does not escape"
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_ = x[0] + y[0]
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}
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