How to Find All Callers of a Function in C++?

Question

I'm refactoring some code in C++, and I want to deprecate some old methods. My current method for finding all of the methods looks like this:

1. Comment out the original method in the source file in which I'm working.
2. Try to compile the code.
3. If a compiler error is found, then make a note comment out the call and try to recompile.
4. Once the compile has completed successfully, I've found all of the calls.

This totally sucks. I've also tried grepping source for the name of the function calls, but I sometimes run into problems with functions of the same name with different arguments, so my compilation makes the C++ compiler resolve the names for me. I've found this question for C#, but my code base is entirely implemented in C++.

Is there a better way to find all of the callers of a class method or function in C++? I'm using GCC on Unix systems, but cross-platform solutions would be superlative.

Answer 1

That's pretty much how I do it. If your code is all in once place a "grep" (or find | grep combo) might do the trick too.

One caviat: This method will very often miss instances that are not conditionally compiled into your current configuration. If your code makes use of #ifdefs to support multiple configurations, a thorough person will try to compile with every configuration to catch all instances.

Answer 2

GCC allows you to decorate variables, functions, and methods with __attribute__((deprecated)), which will cause a warning on all callsites (unless -Wno-deprecated-declarations is given).

class A {
public:
    A() __attribute__((deprecated)) {}
};
int main() {
    A a;
}

$ g++ test.c
test.cc: In function ‘int main()’:
test.cc:6: warning: ‘A::A()’ is deprecated (declared at test.cc:3)

Answer 3

I think what you want is to look at a call graph. See this question for some good suggestions on how to do that.

Answer 4

One option is to run your entire project through a program like Cscope. Which essentially parses the entire source code of your project and builds a database that allows for easy searching of things like all of a function's callers, all references, etc.

I know it works fairly well for C, and they claim it works decently for C++. KScope is a KDE GUI front end for it.

Answer 5

This plugin for Eclipse might be the right tool: CallGraph View

Answer 6

For anyone wanting to do this in Visual Studio under windows....

Visual Assist is really good. It helps a lot with many C++ refactorings, Call graphs, renaming, automatically creating header definitions or generation methods from definitions, etc etc. It's not perfect, nothing like the quality of Java/C# refactoring tools, but really good for C++!!

Answer 7

Eclipse can do this without any plugins. It can be a useful tool for stuff like this even if you don't want to use it for your day-to-day editor.

1. Download, install, and run the Eclipse CDT.
2. Go under File, New, C++ Project. Enter a project name and choose an Empty Makefile project from the Project Type tree view. Uncheck "Use default location" and enter the folder where your project is kept.
3. Click Next, then click Finish.
4. Eclipse will automatically start indexing your project. If it really is a Makefile project, and since you're using g++, you can do a full clean then build from within Eclipse (under the Project menu), and it should automatically use your existing makefiles and automatically discover your include directories and other project settings.
5. Find the prototype of the overloaded function in a source file, right-click on it, choose References, and choose Project. Eclipse will find all references to that function, and only to that particular overload of that function, within your project.

You can also use Eclipse's built-in refactoring support to rename overloaded functions so that they're no longer overloaded. Eclipse is also fully cross-platform; you can use features like its indexer, search references, and refactoring even for projects that are maintained and built in other IDEs.

Answer 8

If you let the Eclipse CDT index your source base, then you should be able to view the calling hierarchy for any function and even perform some refactoring.

You can download the Eclipse IDE for C/C++ Developers (hopefully you can find a port for your particular *NIX) and follow their instructions to get going.

Answer 9

In visual studio, right click on the function name and click "Call Browser" > Show Callers graph

Then in the display window there should be a folder called "Calls to function" that contains all the places that call that function, each of which you can double click on to go to them in the code.