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// run
// Copyright 2015 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.
// windows doesn't work, because Windows exception handling
// delivers signals based on the current PC, and that current PC
// doesn't go into the Go runtime.
// +build !windows
// wasm does not work, because the linear memory is not executable.
// +build !wasm
// This test doesn't work on gccgo/GoLLVM, because they will not find
// any unwind information for the artificial function, and will not be
// able to unwind past that point.
// +build !gccgo
package main
import (
"encoding/binary"
"runtime"
"runtime/debug"
"unsafe"
)
func main() {
debug.SetPanicOnFault(true)
defer func() {
if err := recover(); err == nil {
panic("not panicking")
}
pc, _, _, _ := runtime.Caller(10)
f := runtime.FuncForPC(pc)
if f == nil || f.Name() != "main.f" {
if f == nil {
println("no func for ", unsafe.Pointer(pc))
} else {
println("found func:", f.Name())
}
panic("cannot find main.f on stack")
}
}()
f(20)
}
func f(n int) {
if n > 0 {
f(n - 1)
}
var f struct {
x uintptr
}
// We want to force an illegal instruction, to get a crash
// at a PC value != 0.
// Not all systems make the data section non-executable.
ill := make([]byte, 64)
switch runtime.GOARCH {
case "386", "amd64":
binary.LittleEndian.PutUint16(ill, 0x0b0f) // ud2
case "arm":
binary.LittleEndian.PutUint32(ill, 0xe7f000f0) // no name, but permanently undefined
case "arm64":
binary.LittleEndian.PutUint32(ill, 0xd4207d00) // brk #1000
case "ppc64":
binary.BigEndian.PutUint32(ill, 0x7fe00008) // trap
case "ppc64le":
binary.LittleEndian.PutUint32(ill, 0x7fe00008) // trap
case "mips", "mips64":
binary.BigEndian.PutUint32(ill, 0x00000034) // trap
case "mipsle", "mips64le":
binary.LittleEndian.PutUint32(ill, 0x00000034) // trap
case "s390x":
binary.BigEndian.PutUint32(ill, 0) // undefined instruction
default:
// Just leave it as 0 and hope for the best.
}
f.x = uintptr(unsafe.Pointer(&ill[0]))
p := &f
fn := *(*func())(unsafe.Pointer(&p))
fn()
}
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