问题

以下是翻译好的部分：

我编写了以下短小的Assembly LLVM代码（我知道它只是用于测试，不高效）：

```assembly
define void @main() {
label_41:
%t22 = add i32 0, 0
label_43:
%t23 = add i32 0, 0
}

当我尝试这样运行它时，我收到了一个错误：

Downloads % /usr/local/opt/llvm/bin/lli t02.out
/usr/local/opt/llvm/bin/lli: lli: t02.out:4:1: error: expected instruction opcode
label_43:
^

问题是什么，缺少哪个操作码？

<details>
<summary>英文:</summary>

I wrote the following short Assembly LLVM code (I know it&#39;s not efficent only for testing purposes):

define void @main() {
label_41:
%t22 = add i32 0, 0
label_43:
%t23 = add i32 0, 0
}

When I try to run it like this I get an error:

Downloads % /usr/local/opt/llvm/bin/lli t02.out
/usr/local/opt/llvm/bin/lli: lli: t02.out:4:1: error: expected instruction opcode
label_43:
^

What's the problem, which opcode is missing?

</details>


# 答案1
**得分**: 10

LLVM中的标签开始一个新的块。而且每个块都必须以[终结指令](https://llvm.org/docs/LangRef.html#terminator-instructions)（如`ret`或`br`）结束。

LLVM出现错误是因为它达到了一个标签，但前面的块没有以终结指令结束。要使其编译通过，您需要在`label_43:`之前和函数结束之前添加终结指令。

<details>
<summary>英文:</summary>

A label in LLVM starts a new block. And each block must end with a [terminator instruction](https://llvm.org/docs/LangRef.html#terminator-instructions) such as `ret` or `br`.

LLVM is giving the error because it reached a label but the preceding block didn&#39;t end with a terminator instruction. To get this to compile, you need to add terminator instructions before `label_43:` and before the end of the function.

</details>