mirror of
https://github.com/golang/go
synced 2024-11-23 07:50:05 -07:00
66 lines
1.3 KiB
Go
66 lines
1.3 KiB
Go
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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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// Make sure return values aren't scanned until they
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// are initialized, when calling functions and methods
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// via reflect.
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package main
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import (
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"io"
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"reflect"
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"runtime"
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"unsafe"
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)
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var badPtr uintptr
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var sink []byte
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func init() {
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// Allocate large enough to use largeAlloc.
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b := make([]byte, 1<<16-1)
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sink = b // force heap allocation
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// Any space between the object and the end of page is invalid to point to.
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badPtr = uintptr(unsafe.Pointer(&b[len(b)-1])) + 1
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}
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func f(d func(error) error) error {
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// Initialize callee args section with a bad pointer.
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g(badPtr, badPtr, badPtr, badPtr)
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// Then call a function which returns a pointer.
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// That return slot starts out holding a bad pointer.
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return d(io.EOF)
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}
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//go:noinline
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func g(x, y, z, w uintptr) {
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}
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type T struct {
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}
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func (t *T) Foo(e error) error {
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runtime.GC()
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return e
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}
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func main() {
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// Functions
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d := reflect.MakeFunc(reflect.TypeOf(func(e error) error { return e }),
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func(args []reflect.Value) []reflect.Value {
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runtime.GC()
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return args
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}).Interface().(func(error) error)
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f(d)
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// Methods
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x := reflect.ValueOf(&T{}).Method(0).Interface().(func(error) error)
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f(x)
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}
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