goexit      bool
	deferreturn bool
}

// savedOpenDeferState tracks the extra state from _panic that's
// necessary for deferreturn to pick up where gopanic left off,
// without needing to unwind the stack.
type savedOpenDeferState struct {
	retpc           uintptr
	deferBitsOffset uintptr
	slotsOffset     uintptr
}

// ancestorInfo records details of where a goroutine was started.