private static int getMonitorExitSlot(StructuredBlock stmt) {
		if (stmt instanceof InstructionBlock) {
			Expression instr = ((InstructionBlock) stmt).getInstruction();
			if (instr instanceof MonitorExitOperator) {
				MonitorExitOperator monExit = (MonitorExitOperator) instr;
				if (monExit.getFreeOperandCount() == 0
						&& (monExit.getSubExpressions()[0] instanceof LocalLoadOperator))
					return ((LocalLoadOperator) monExit.getSubExpressions()[0])
							.getLocalInfo().getSlot();
			}
		}
		return -1;
	}