mirror of
https://github.com/golang/go
synced 2024-11-22 07:54:40 -07:00
4f61fc96b2
The ken directory is untouched so we have some examples with explicit semis. R=gri CC=golang-dev https://golang.org/cl/2157041
33 lines
1.1 KiB
Go
33 lines
1.1 KiB
Go
// [ $GOOS != nacl ] || exit 0 # do not bother on NaCl
|
|
// $G $D/$F.go && $L $F.$A &&
|
|
// ((! sh -c ./$A.out) >/dev/null 2>&1 || echo BUG: should fail)
|
|
|
|
// 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
|
|
|
|
import "unsafe"
|
|
|
|
var dummy [512<<20]byte // give us a big address space
|
|
func main() {
|
|
// the test only tests what we intend to test
|
|
// if dummy starts in the first 256 MB of memory.
|
|
// otherwise there might not be anything mapped
|
|
// at the address that might be accidentally
|
|
// dereferenced below.
|
|
if uintptr(unsafe.Pointer(&dummy)) > 256<<20 {
|
|
panic("dummy too far out")
|
|
}
|
|
|
|
// The problem here is that indexing into p[] with a large
|
|
// enough index jumps out of the unmapped section
|
|
// at the beginning of memory and into valid memory.
|
|
// Pointer offsets and array indices, if they are
|
|
// very large, need to dereference the base pointer
|
|
// to trigger a trap.
|
|
var p *[1<<30]byte = nil
|
|
println(p[256<<20]) // very likely to be inside dummy, but should crash
|
|
}
|