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go/test/nilptr/arrayindex.go
Russ Cox 0c54225b51 remove nacl
The recent linker changes broke NaCl support
a month ago, and there are no known users of it.

The NaCl code can always be recovered from the
repository history.

R=adg, r
CC=golang-dev
https://golang.org/cl/3671042
2010-12-15 11:49:23 -05:00

27 lines
733 B
Go

// $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 x byte
func main() {
var p *[1<<30]byte = nil
x = 123
// The problem here is not the use of unsafe:
// it 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.
println(p[uintptr(unsafe.Pointer(&x))]) // should crash
}