// return PC (pushing a frame for the call). Otherwise, it should be
// left alone so that LR is used as sigpanic's return PC, effectively
// replacing the top-most frame with sigpanic. This is used by
// preparePanic.
func shouldPushSigpanic(gp *g, pc, lr uintptr) bool {
	if pc == 0 {
		// Probably a call to a nil func. The old LR is more
		// useful in the stack trace. Not pushing the frame

		// augmenting the stack frame would break
		// the unwinding code.
		gp.sig = sig
		gp.sigcode0 = uintptr(c.sigcode())
		gp.sigcode1 = c.fault()
		gp.sigpc = c.sigpc()

		c.preparePanic(sig, gp)
		return
	}

	if c.sigFromUser() || flags&_SigNotify != 0 {
		if sigsend(sig) {
			return
		}
	}

	if c.sigFromUser() && signal_ignored(sig) {
		return
	}