使用clang API处理C ++函数以插入代码 [英] Handle C++ functions with clang API to insert code

问题描述

我需要预处理一些 C ++ 文件，以自动插入代码进行测试和分析，我需要使用 clang API 。

现在，我想要能够执行以下操作：
如果有一个函数：

  int SomeFn（int a，int b，int c）{
 doStuff（）; 
} 
  

我想对其进行预处理，看起来像这样：

  int SomeFn（int a，int b，int c）{
 cout< SomeFn使用以下参数调用：a =<< a<< ，b =< b<< ，c =< c<< endl; 
 doStuff（）; 
} 
  

我试图扩展 ASTConsumer 并使用 HandleTopLevelDecl 和 HandleTopLevelSingleDecl 方法并检查传递的 Decls 都是 FunctionDecls 并将它们向下转，所以我可以得到他们的名字和body-locations。
但我不能处理类方法，只有全局函数。

我在 ASTConsumer class HandleTagDeclDefinition（TagDecl * D）。文档说：

这个回调在每次
时调用TagDecl（例如struct，union，enum，
类）。

但是看起来这个方法甚至在我测试的时候没有被调用。

所以我的问题是，什么是正确的方式来完成这项任务？在clang API中如何表示C ++类？也许有人知道，在哪里可以找到例子，因为clang API没有记录。

---

UPDATE：

我知道还有 Visitors 的概念，还有一个方法 VisitRecordDecl（RecordDecl * D） / code>。该文档说， RecordDecl 表示类。所以我扩展了 RecursiveASTVisitor 并实现了 VisitRecordDecl（RecordDecl * D），但似乎这个方法没有被调用。
而是调用VisitVarDecl ，当类定义为find时，就好像它被看作一个变量声明。
所以我有点困惑。我希望有人可以帮助...

$ b

UPDATE2：

我试图解析另一个文件，这次clang发现一个 RecordDecl 。但是该文件定义了一个结构体和两个类，所以我认为我的clang代码解析 C而不是C ++ 。是否有任何设置在C和C ++之间切换？

解决方案

是否有任何设置可以在C和C ++之间切换？

最后，我找到了如何处理这个问题：

从 ASTConsumer 和 RecursiveASTVisitor 扩展以遍历AST并实现 VisitCXXRecordDecl（CXXRecordDecl * D）。然后我必须为预处理器设置 LangOptions 参数，所以它会解析C ++。

  langOpts.CPlusPlus = 1; 
  

我的错误是认为它会立即解析C ++，但是不是这样将C解析为默认值，因此无法识别类。

I need to preprocess some C++ files to automatically insert code for testing and profiling, and I need to do it with the clang API.

For now, I want to be able to do the following: If there is a function:

int SomeFn(int a, int b, int c) {
    doStuff();
}

I want to preprocess it, that it looks like this:

int SomeFn(int a, int b, int c) {
    cout << "SomeFn is invoked with the following arguments: a=" << a << ", b=" << b << ", c=" << c << endl;
    doStuff();
}

I've tried to extend ASTConsumer and use the methods HandleTopLevelDecl and HandleTopLevelSingleDecl and check if the passed Decls are FunctionDecls and downcast them, so I can get their names and body-locations. But I can't handle class-methods that way, only global functions.

I found a function in the ASTConsumer class HandleTagDeclDefinition(TagDecl* D). The documentation says:

This callback is invoked each time a TagDecl (e.g. struct, union, enum, class) is completed.

But it looks like this method isn't even invoked, when I test it.

So my question is, what would be the right way to do this task? And how are C++ classes are represented in the clang API? Maybe someone knows, where I can find examples because the clang API is poorly documented.

---

UPDATE:

I know there is also the concept of Visitors and there is a method VisitRecordDecl(RecordDecl *D). The documentation says that RecordDecl represents classes. So I extended RecursiveASTVisitor and implemented VisitRecordDecl(RecordDecl *D) but it seems, that this method isn't invoked neither. Instead VisitVarDecl is invoked, when a class definition is find, as if it is seen as a variable declaration. So I'm a bit confused. I hope, someone can help...

---

UPDATE2:

I tried to parse another file and this time clang found one RecordDecl. But the file defined one struct and two classes, so I think my clang code parses C instead of C++. Are there any settings to switch between C and C++ ?

解决方案

Are there any settings to switch between C and C++ ?

Finally I found out how to handle this:

I extended from ASTConsumer and RecursiveASTVisitor<MyConsumer> to traverse the AST and implemented VisitCXXRecordDecl(CXXRecordDecl* D). Then I had to set the LangOptions parameter for the preprocessor, so it parses C++.

langOpts.CPlusPlus = 1;

My fault was to think that it would parse C++ right away, but that was not the case, it parses C as default and so doesn't recognize classes.

这篇关于使用clang API处理C ++函数以插入代码的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！