编写我自己的C ++编译器 [英] Writing my own C++ compiler

问题描述

我想在c ++中编写我自己的c ++编译器。让我们说我要在VS中构建它。
主要思想是它必须已经能够编译自身，这意味着我不能使用STL，boost等库，我可以吗？
所以，这是否意味着我必须从头开始做一切 - 从词法分析器到二进制代码生成？

解决方案

这意味着我不能使用STL，boost等库。

为什么不呢？他们不使用任何魔法（因为它），只有纯C ++。所以如果你的编译器知道所有的C ++，这不应该是一个问题。这当然是完全可笑的，考虑到C ++可能是最难以解析编程语言存在今天，从头构建一个编译器可能需要几百（！）的人年。 （我实际上没有发明这个数字 - 我读它在某个地方。不幸的是，我现在找不到源。）

但是，完全假设所以假设的答案是：不，你可以使用现有的库。

那么为什么C ++这么难编译？ p>

首先，C ++是一种上下文相关的语言。生成这样的语法的解析器要困难得多。然而，这仍然是最简单的方面之一。使C ++真的很难的是与声明/定义，名称查找（考虑依赖于参数的名称查找）隐式转换规则相关的一些规则，当然还有模板的解析。我认为现有的编译器在所有情况下都不会有正确的模板。

考虑 Andrej Alexandrescu的写作模板函数版本的 min 和 max 版本。他声称没有编译器成功编译他的（理论上正确的）代码：

这将是那么好，提到。遗憾的是，Min不能使用任何我可以访问的编译器。公平地说，每个编译器对不同的代码片段进行阻塞。

I want to write my own c++ compiler in c++. Let´s say I´m going to build it in VS. The main idea is that it must have been able to compile itself, which means I cannot use STL, boost, etc. libraries, can I? So, does it mean that I must do everything from scratch - from lexical analyser to binary code generation?

解决方案

which means I cannot use STL, boost, etc. libraries, can I?

Why not? They don't use any magic (as it were), only plain C++. So if your compiler knows all of C++, this shouldn't be a problem. Which is of course completely ludicrous, considering that C++ is probably the hardest to parse programming language in existence today, and that building a compiler from scratch would probably take hundreds (!) of man-years. (I didn't actually invent this number – I read it somewhere. Unfortunately, I'm unable to find the source now.)

But then, I guess the question was completely hypothetical so the hypothetical answer is: no, you can use existing libraries.

So why is C++ so hard to compile?

First off, C++ is a context sensitive language. Producing a parser for such a grammar is much harder. However, this is still one of the simplest aspects. What makes C++ really hard are certain rules relating to declarations/definitions, name lookup (consider argument-dependent name lookup) implicit conversion rules, and of course the resolution of templates. I think no existing compiler gets templates right in all circumstances.

Consider Andrej Alexandrescu's efford to write template-function versions of min and max that behave as correctly as the macro version. He claims that no compiler succeeds in compiling his (theoretically correct) code:

It would all be so nice, but there's a little detail worth mentioning. Sadly, Min doesn't work with any compiler I have access to. In fairness, each compiler chokes on a different piece of code.

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