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go/test/escape.go
Russ Cox 391425ae55 if take address of local, move to heap.
heuristic to not print bogus strings.
fix one error message format.

R=ken
OCL=23849
CL=23851
2009-01-29 17:38:58 -08:00

176 lines
3.1 KiB
Go

// $G $D/$F.go && $L $F.$A && ./$A.out
// Copyright 2009 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.
package main
// check for correct heap-moving of escaped variables.
// it is hard to check for the allocations, but it is easy
// to check that if you call the function twice at the
// same stack level, the pointers returned should be
// different.
var bad = false
var allptr = make([]*int, 0, 100);
func noalias(p, q *int, s string) {
n := len(allptr);
*p = -(n+1);
*q = -(n+2);
allptr = allptr[0:n+2];
allptr[n] = p;
allptr[n+1] = q;
n += 2;
for i := 0; i < n; i++ {
if allptr[i] != nil && *allptr[i] != -(i+1) {
println("aliased pointers", -(i+1), *allptr[i], "after", s);
allptr[i] = nil;
bad = true;
}
}
}
func val(p, q *int, v int, s string) {
if *p != v {
println("wrong value want", v, "got", *p, "after", s);
bad = true;
}
if *q != v+1 {
println("wrong value want", v+1, "got", *q, "after", s);
bad = true;
}
}
func chk(p, q *int, v int, s string) {
val(p, q, v, s);
noalias(p, q, s);
}
func chkalias(p, q *int, v int, s string) {
if p != q {
println("want aliased pointers but got different after", s);
}
if *q != v+1 {
println("wrong value want", v+1, "got", *q, "after", s);
}
}
func i_escapes(x int) *int {
var i int;
i = x;
return &i;
}
func j_escapes(x int) *int {
var j int = x;
j = x;
return &j;
}
func k_escapes(x int) *int {
k := x;
return &k;
}
func in_escapes(x int) *int {
return &x;
}
func send(c chan int, x int) {
c <- x;
}
func select_escapes(x int) *int {
c := make(chan int);
go send(c, x);
select {
case req := <-c:
return &req;
}
return nil;
}
func select_escapes1(x int, y int) (*int, *int) {
c := make(chan int);
var a [2]int;
var p [2]*int;
a[0] = x;
a[1] = y;
for i := 0; i < 2; i++ {
go send(c, a[i]);
select {
case req := <-c:
p[i] = &req;
}
}
return p[0], p[1]
}
func range_escapes(x int) *int {
var a [1]int;
a[0] = x;
for k, v := range a {
return &v;
}
return nil;
}
// *is* aliased
func range_escapes2(x, y int) (*int, *int) {
var a [2]int;
var p [2]*int;
a[0] = x;
a[1] = y;
for k, v := range a {
p[k] = &v;
}
return p[0], p[1]
}
// *is* aliased
func for_escapes2(x int, y int) (*int, *int) {
var p [2]*int;
n := 0;
for i := x; n < 2; i = y {
p[n] = &i;
n++;
}
return p[0], p[1]
}
func main() {
p, q := i_escapes(1), i_escapes(2);
chk(p, q, 1, "i_escapes");
p, q = j_escapes(3), j_escapes(4);
chk(p, q, 3, "j_escapes");
p, q = k_escapes(5), k_escapes(6);
chk(p, q, 5, "k_escapes");
p, q = in_escapes(7), in_escapes(8);
chk(p, q, 7, "in_escapes");
p, q = select_escapes(9), select_escapes(10);
chk(p, q, 9, "select_escapes");
p, q = select_escapes1(11, 12);
chk(p, q, 11, "select_escapes1");
p, q = range_escapes(13), range_escapes(14);
chk(p, q, 13, "range_escapes");
p, q = range_escapes2(101, 102);
chkalias(p, q, 101, "range_escapes2");
p, q = for_escapes2(103, 104);
chkalias(p, q, 103, "for_escapes2");
if bad {
panic("BUG: no escape");
}
}