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go/test/fixedbugs/issue12588.go
David Chase 745cdc3ad7 cmd/compile: repair escape analysis of range &fixedArray
The existing test did not take into account the implicit
dereference of &fixedArray and thus heap-escaped when it
was not necessary.

Also added a detailed test for this and related cases.

Fixes #12588

Change-Id: I951e9684a093082ccdca47710f69f4366bd6b3cf
Reviewed-on: https://go-review.googlesource.com/15130
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
2015-10-01 18:49:18 +00:00

89 lines
2.0 KiB
Go

// errorcheck -0 -m -l
// Copyright 2015 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.
// Tests escape analysis for range of arrays.
// Compiles but need not run. Inlining is disabled.
package main
type A struct {
b [3]uint64
}
type B struct {
b [3]*uint64
}
func f(a A) int {
for i, x := range &a.b { // ERROR "f &a.b does not escape"
if x != 0 {
return 64*i + int(x)
}
}
return 0
}
func g(a *A) int { // ERROR "g a does not escape"
for i, x := range &a.b { // ERROR "g &a.b does not escape"
if x != 0 {
return 64*i + int(x)
}
}
return 0
}
func h(a *B) *uint64 { // ERROR "leaking param: a to result ~r1 level=1"
for i, x := range &a.b { // ERROR "h &a.b does not escape"
if i == 0 {
return x
}
}
return nil
}
func h2(a *B) *uint64 { // ERROR "leaking param: a to result ~r1 level=1"
p := &a.b // ERROR "h2 &a.b does not escape"
for i, x := range p {
if i == 0 {
return x
}
}
return nil
}
// Seems like below should be level=1, not 0.
func k(a B) *uint64 { // ERROR "leaking param: a to result ~r1 level=0"
for i, x := range &a.b { // ERROR "k &a.b does not escape"
if i == 0 {
return x
}
}
return nil
}
var sink *uint64
func main() {
var a1, a2 A
var b1, b2, b3, b4 B
var x1, x2, x3, x4 uint64 // ERROR "moved to heap: x1" "moved to heap: x3"
b1.b[0] = &x1 // ERROR "&x1 escapes to heap"
b2.b[0] = &x2 // ERROR "main &x2 does not escape"
b3.b[0] = &x3 // ERROR "&x3 escapes to heap"
b4.b[0] = &x4 // ERROR "main &x4 does not escape"
f(a1)
g(&a2) // ERROR "main &a2 does not escape"
sink = h(&b1) // ERROR "main &b1 does not escape"
h(&b2) // ERROR "main &b2 does not escape"
sink = h2(&b1) // ERROR "main &b1 does not escape"
h2(&b4) // ERROR "main &b4 does not escape"
x1 = 17
println("*sink=", *sink) // Verify that sink addresses x1
x3 = 42
sink = k(b3)
println("*sink=", *sink) // Verify that sink addresses x3
}