llvm ir 返回人类可读的源语言？
有没有一种简单的方法可以从 llvm ir 转到工作源代码？
具体来说，我想从一些简单的 C++ 代码开始，这些代码仅修改 POD（主要是整数、浮点数等数组），将其转换为 llvm ir，对其执行一些简单的分析和翻译，然后将其转换回 C++ 代码？
它并不真正介意任何名称被破坏，我只是希望能够在进行与机器相关的优化之前对源代码进行修改。
Is there an easy way of going from llvm ir to working source code?
Specifically, I'd like to start with some simple C++ code that merely modifies PODs (mainly arrays of ints, floats, etc), convert it to llvm ir, perform some simple analysis and translation on it and then convert it back into C++ code?
It don't really mind about any of the names getting mangled, I'd just like to be able to hack about with the source before doing the machine-dependent optimisations.
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实际上有很多选择。您可能感兴趣的两个是
-march=c和-march=cpp，它们是 llc 的选项。运行：
这会将
code.ll中的 LLVM 位码转换回 C 并将其放入code.c中。另外：
这与 C 输出引擎不同。它实际上会写出可以运行来重建 IR 的 C++ 代码。我使用此工具将 LLVM IR 嵌入到程序中，而无需处理解析位码文件或任何其他内容。
-march=cpp有更多选项，您可以通过llc --help查看，例如-cppgen=，它控制 IR 的多少输出 C++ 重建。There are number of options actually. The 2 that you'll probably be interested in are
-march=cand-march=cpp, which are options to llc.Run:
This will convert the LLVM bitcode in
code.llback to C and put it incode.c.Also:
This is different than the C output engine. It actually will write out C++ code that can be run to reconstruct the IR. I use this personal to embed LLVM IR in a program without having to deal with parsing bitcode files or anything.
-march=cpphas more options you can see withllc --help, such as-cppgen=which controls how much of the IR the output C++ reconstructs.CppBackend 已被删除。自 2016-05-05，r268631 以来，我们没有 -march=cpp 和 -march=c 选项。
CppBackend was removed. We have no -march=cpp and -march=c option since 2016-05-05, r268631.
这里有一个问题......可能无法轻松地将 IR 表示回语言。
我的意思是，您可能能够获得一些表示，但其可读性可能较差。
问题是 IR 不关心高级语义，如果没有它......
我宁愿建议你学习阅读 IR。我不用花那么多功夫就能读懂其中的一部分，而且我还远远不是 llvm 专家。
否则，您可以从 IR 中进行 C 代码。它不会与您的 C++ 代码更加相似，但如果没有 ssa 和 phi 节点，您可能会感觉更好。
There is an issue here... it might not be possible to easily represent the IR back into the language.
I mean, you'll probably be able to get some representation, but it might be less readable.
The issue is that the IR is not concerned with high-level semantic, and without it...
I'd rather advise you to learn to read the IR. I can read a bit of it without that much effort, and I am far from being a llvm expert.
Otherwise, you can C code from the IR. It won't be much more similar to your C++ code, but you'll perhaps feel better without ssa and phi nodes.