How to use Clang as a library

Question

I am doing my dissertation and I have to parse and tokenize the source code into individual functions. For every function I would like to extract names of types, called function names and type casts. Is the clang the right tool for that kind of job? If yes how can i do this?

Below is a simple C function. With bold are the extracted items I want:

static char func1(unsigned int a, struct foo *b)
{
    int c = 0;
    struct bar *d;

    if (a == 0) {
        d = func2((int) a);
    } else {
        c = func3((struct bar *) b);
    }

    return c;
}

score 8 · Accepted Answer · answered Jun 05 '16 at 17:59

8

Yes, Clang is the right tool to do this job.

You should take a look a libclang.

You can find enough information on internet, but I personally can recommend two great articles:

Parsing C++ in Python with Clang by Eli Bendersky

Introduction to libclang by Mike Ash

If you prefer to watch videos, then I can recommend to look at the presentation on libclang here: 2010 LLVM Developers' Meeting, look for libclang: Thinking Beyond the Compiler

answered Jun 05 '16 at 17:59

AlexDenisov

4,022
25
31

Thank you for your suggestions. After doing some reading of my own I came to clang's documentation. It is saying that you can use clang for different stages of compilation. If I am correct I am interested for the preprocessing stage and the parsing and semantic analysis stage. Those stages can be invoked using the -fsyntax-only flag. However using this flag clang does not return the AST file as said in the documentation. Any ideas? Am I missing some tools for example from llvm, thats why it doesnot generate the AST? – Andreas Geo Jun 05 '16 at 18:18
I can't say for sure about the purpose of `-fsyntax-only`, but I assume it's there for easier debugging and maybe for some static analysis, when we don't need to proceed after semantic analysis is done. `libclang` covers everything you need, it is basically does everything until code generation, it includes preprocessing (#include's, C macros), lexing, parsing, and semantic analysis. – AlexDenisov Jun 05 '16 at 18:47
I got an idea from reading the articles you posted. I can understand that clang is a compiler but also they provide all of its individual components to create my own preprocessor tool which I can configure as I like using their libraries and functions? Because this is out of the scope of my project, is there soething which is ready to use? – Andreas Geo Jun 05 '16 at 19:48

score 0 · Answer 2 · answered May 31 '23 at 14:46

0

I would like to recommend LibTooling. If you only need Preprocessing, PreprocessOnlyAction is helpful. If information of Abstract Syntax Tree is needed, you better choose ASTFrontendAction.

answered May 31 '23 at 14:46

Layne Liu

452
5
10

How to use Clang as a library

2 Answers2