[cfe-dev] Libclang. Cross-referencing translation units with Unified Symbol Resolution USR.

Juan Jose Lopez Villarejo jj.lopezvillarejo at cern.ch
Wed Jan 8 00:51:59 PST 2014


I have spent the last months in developing a documentation tool based on lib clang & its python bindings, which can generate activity diagrams from annotated C++ code. It works for a single translation unit, which in my case is a single .cpp source file (e.g., ‘main.cpp’). Now I would like to make this tool work properly for a code consisting of several source files.

Statement of the issue
In this tool, calls to functions (or class methods) can be displayed on the generated diagrams, and a hyperlink allows access to the diagram for the called function from the ‘caller diagram’.

>From the call_node, I can get the function_node (inside the same translation unit) with a simple


(this is with the python bindings to libclang). The call_node does not have an associated Unified Symbol Resultion USR, while the associated function_node does:

call_node.get_usr() —>  displays ‘’, nothing
call_node.get_definition().get_usr() —>  displays ‘function’s USR’

The problem comes when there is a call from a given source file to a function (method) that is defined in another source file. In that case,

call_node.get_definition() —> None

So, I have no way to establish a (hyper)link between the caller and the callee.

Attempts of resolution

I have tried to put several translation units into the libclang index, with:

index = clang.cindex.Index.create()
tu_aux1=index.parse("./include/t.h",args, None, 2)
tu = index.parse("./simple_demo_src.cpp",args)

In this example, the file being explored is ‘simple_demo_src.cpp’. Some of the functions that are called from ‘simple_demo_src.cpp’ are defined in "./include/t.h" and "./src/t.cpp ».
I get the same behavior as explained before:
call_node.get_definition() —> None

Any Ideas?
(not preferred solution might involve combining all source files into a single one. How?)

Your ideas will be greatly appreciated. I’m hoping to contribute this tool to the community.


Juan Lopez-Villarejo

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