go/test/fixedbugs/issue5820.go

// run

// Copyright 2013 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.

// issue 5820: register clobber when clearfat and 64 bit arithmetic is interleaved.

package main

func main() {
	array := make([][]int, 2)
	index := uint64(1)
	array[index] = nil
	if array[1] != nil {
		panic("array[1] != nil")
	}
}
cmd/8g: Make clearfat non-interleaved with pointer calculations. clearfat (used to zero initialize structures) will use AX for x86 block ops. If we write to AX while calculating the dest pointer, we will fill the structure with incorrect values. Since 64-bit arithmetic uses AX to synthesize a 64-bit register, getting an adress by indexing with 64-bit ops can clobber the register. Fixes #5820. R=golang-dev, rsc CC=golang-dev https://golang.org/cl/11383043 2013-07-17 09:04:34 +00:00			`// run`

all: make copyright headers consistent with one space after period Follows suit with https://go-review.googlesource.com/#/c/20111. Generated by running $ grep -R 'Go Authors. All' * \| cut -d":" -f1 \| while read F;do perl -pi -e 's/Go Authors. All/Go Authors. All/g' $F;done The code in cmd/internal/unvendor wasn't changed. Fixes #15213 Change-Id: I4f235cee0a62ec435f9e8540a1ec08ae03b1a75f Reviewed-on: https://go-review.googlesource.com/21819 Reviewed-by: Ian Lance Taylor <iant@golang.org> Run-TryBot: Ian Lance Taylor <iant@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org> 2016-04-10 21:32:26 +00:00			`// Copyright 2013 The Go Authors. All rights reserved.`
cmd/8g: Make clearfat non-interleaved with pointer calculations. clearfat (used to zero initialize structures) will use AX for x86 block ops. If we write to AX while calculating the dest pointer, we will fill the structure with incorrect values. Since 64-bit arithmetic uses AX to synthesize a 64-bit register, getting an adress by indexing with 64-bit ops can clobber the register. Fixes #5820. R=golang-dev, rsc CC=golang-dev https://golang.org/cl/11383043 2013-07-17 09:04:34 +00:00			`// Use of this source code is governed by a BSD-style`
			`// license that can be found in the LICENSE file.`

			`// issue 5820: register clobber when clearfat and 64 bit arithmetic is interleaved.`

			`package main`

			`func main() {`
			`array := make([][]int, 2)`
			`index := uint64(1)`
			`array[index] = nil`
			`if array[1] != nil {`
			`panic("array[1] != nil")`
			`}`
			`}`