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// run
// Copyright 2016 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 17381: make sure leave function with non-empty frame
// saves link register, so that traceback will work.
package main
import (
"runtime"
"unsafe"
)
func main() {
defer func() {
if recover() == nil {
panic("did not panic")
}
pcs := make([]uintptr, 20)
n := runtime.Callers(1, pcs)
for _, pc := range pcs[:n] {
if runtime.FuncForPC(pc).Name() == "main.main" {
return
}
}
panic("cannot find main.main in backtrace")
}()
prep()
f() // should panic
}
func funcPC(f interface{}) uintptr {
var ptr uintptr
return **(**uintptr)(unsafe.Pointer(uintptr(unsafe.Pointer(&f)) + unsafe.Sizeof(ptr)))
}
//go:noinline
func f() {
var t [1]int // non-empty frame
*(*int)(nil) = t[0]
}
var p = funcPC(runtime.GC) + 8
//go:noinline
func prep() {
// put some garbage on stack
var x = [20]uintptr{p, p, p, p, p, p, p, p, p, p, p, p, p, p, p, p, p, p, p, p}
_ = x
}
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