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https://github.com/golang/go
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aa9c1a8f80
When the slice/string length is very large, probably artifically large as in CL 97523, adding BX (length) to R11 (pointer) overflows. As a result, checking DI < R11 yields the wrong result. Since they will be equal when the loop is done, just check DI != R11 instead. Yes, the pointer itself could overflow, but if that happens, something else has gone pretty wrong; not our concern here. Fixes #24187 Change-Id: I2f60fc6ccae739345d01bc80528560726ad4f8c6 Reviewed-on: https://go-review.googlesource.com/97802 Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Keith Randall <khr@golang.org>
34 lines
602 B
Go
34 lines
602 B
Go
// +build amd64p32
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// run
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// Copyright 2018 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package main
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import (
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"bytes"
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"fmt"
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"unsafe"
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)
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func main() {
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b := make([]byte, 128)
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for i := range b {
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b[i] = 1
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}
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if bytes.IndexByte(b, 0) != -1 {
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panic("found 0")
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}
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for i := range b {
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b[i] = 0
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c := b
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*(*int)(unsafe.Pointer(uintptr(unsafe.Pointer(&c)) + unsafe.Sizeof(uintptr(0)))) = 1<<31 - 1
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if bytes.IndexByte(c, 0) != i {
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panic(fmt.Sprintf("missing 0 at %d\n", i))
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}
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b[i] = 1
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}
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}
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