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// 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.
// Test, using compiler diagnostic flags, that the escape analysis is working.
// Compiles but does not run. Inlining is disabled.
// Registerization is disabled too (-N), which should
// have no effect on escape analysis.
package main
import "fmt"
func main() {
// Just run test over and over again. This main func is just for
// convenience; if test were the main func, we could also trigger
// the panic just by running the program over and over again
// (sometimes it takes 1 time, sometimes it takes ~4,000+).
for iter := 0; ; iter++ {
if iter%50 == 0 {
fmt.Println(iter) // ERROR "iter escapes to heap$" "... argument does not escape$"
}
test1(iter)
test2(iter)
test3(iter)
test4(iter)
test5(iter)
test6(iter)
}
}
func test1(iter int) {
const maxI = 500
m := make(map[int][]int) // ERROR "make\(map\[int\]\[\]int\) escapes to heap$"
// The panic seems to be triggered when m is modified inside a
// closure that is both recursively called and reassigned to in a
// loop.
// Cause of bug -- escape of closure failed to escape (shared) data structures
// of map. Assign to fn declared outside of loop triggers escape of closure.
// Heap -> stack pointer eventually causes badness when stack reallocation
// occurs.
var fn func() // ERROR "moved to heap: fn$"
for i := 0; i < maxI; i++ { // ERROR "moved to heap: i$"
// var fn func() // this makes it work, because fn stays off heap
j := 0 // ERROR "moved to heap: j$"
fn = func() { // ERROR "func literal escapes to heap$"
m[i] = append(m[i], 0)
if j < 25 {
j++
fn()
}
}
fn()
}
if len(m) != maxI {
panic(fmt.Sprintf("iter %d: maxI = %d, len(m) = %d", iter, maxI, len(m))) // ERROR "iter escapes to heap$" "len\(m\) escapes to heap$" "maxI escapes to heap$" "... argument does not escape$"
}
}
func test2(iter int) {
const maxI = 500
m := make(map[int][]int) // ERROR "make\(map\[int\]\[\]int\) does not escape$"
// var fn func()
for i := 0; i < maxI; i++ {
var fn func() // this makes it work, because fn stays off heap
j := 0
fn = func() { // ERROR "func literal does not escape$"
m[i] = append(m[i], 0)
if j < 25 {
j++
fn()
}
}
fn()
}
if len(m) != maxI {
panic(fmt.Sprintf("iter %d: maxI = %d, len(m) = %d", iter, maxI, len(m))) // ERROR "iter escapes to heap$" "len\(m\) escapes to heap$" "maxI escapes to heap$" "... argument does not escape$"
}
}
func test3(iter int) {
const maxI = 500
var x int // ERROR "moved to heap: x$"
m := &x
var fn func() // ERROR "moved to heap: fn$"
for i := 0; i < maxI; i++ {
// var fn func() // this makes it work, because fn stays off heap
j := 0 // ERROR "moved to heap: j$"
fn = func() { // ERROR "func literal escapes to heap$"
if j < 100 {
j++
fn()
} else {
*m = *m + 1
}
}
fn()
}
if *m != maxI {
panic(fmt.Sprintf("iter %d: maxI = %d, *m = %d", iter, maxI, *m)) // ERROR "\*m escapes to heap$" "iter escapes to heap$" "maxI escapes to heap$" "... argument does not escape$"
}
}
func test4(iter int) {
const maxI = 500
var x int
m := &x
// var fn func()
for i := 0; i < maxI; i++ {
var fn func() // this makes it work, because fn stays off heap
j := 0
fn = func() { // ERROR "func literal does not escape$"
if j < 100 {
j++
fn()
} else {
*m = *m + 1
}
}
fn()
}
if *m != maxI {
panic(fmt.Sprintf("iter %d: maxI = %d, *m = %d", iter, maxI, *m)) // ERROR "\*m escapes to heap$" "iter escapes to heap$" "maxI escapes to heap$" "... argument does not escape$"
}
}
type str struct {
m *int
}
func recur1(j int, s *str) { // ERROR "s does not escape"
if j < 100 {
j++
recur1(j, s)
} else {
*s.m++
}
}
func test5(iter int) {
const maxI = 500
var x int // ERROR "moved to heap: x$"
m := &x
var fn *str
for i := 0; i < maxI; i++ {
// var fn *str // this makes it work, because fn stays off heap
fn = &str{m} // ERROR "&str{...} escapes to heap"
recur1(0, fn)
}
if *m != maxI {
panic(fmt.Sprintf("iter %d: maxI = %d, *m = %d", iter, maxI, *m)) // ERROR "\*m escapes to heap$" "iter escapes to heap$" "maxI escapes to heap$" "... argument does not escape$"
}
}
func test6(iter int) {
const maxI = 500
var x int
m := &x
// var fn *str
for i := 0; i < maxI; i++ {
var fn *str // this makes it work, because fn stays off heap
fn = &str{m} // ERROR "&str{...} does not escape"
recur1(0, fn)
}
if *m != maxI {
panic(fmt.Sprintf("iter %d: maxI = %d, *m = %d", iter, maxI, *m)) // ERROR "\*m escapes to heap$" "iter escapes to heap$" "maxI escapes to heap$" "... argument does not escape$"
}
}
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