Traversing the Clang AST using Python

Question

I am working on using clang bingings python to travers c/c++ code into AST,how can I get a tree based AST structure? Some pointers on where to start, tutorials or anything in this regard will be of great help!!!

I found a very useful work(If you want to check this out ,here is the link:https://www.chess.com/blog/lockijazz/using-python-to-traverse-and-modify-clang-s-ast-tree) and tried his code,unfortunately I didn't get a useful output.

function_calls = []           
function_declarations = []     
def traverse(node):

    for child in node.get_children():
        traverse(child)

    if node.type == clang.cindex.CursorKind.CALL_EXPR:
        function_calls.append(node)

    if node.type == clang.cindex.CursorKind.FUNCTION_DECL:
        function_declarations.append(node)


    print 'Found %s [line=%s, col=%s]' % (node.displayname, node.location.line, node.location.column)

clang.cindex.Config.set_library_path("/Users/tomgong/Desktop/build/lib")
index = clang.cindex.Index.create()

tu = index.parse(sys.argv[1])

root = tu.cursor        
traverse(root)

Answer 1

Just in case anyone was having trouble still, I found that if you should be using kind instead of type

you can run clang.cindex.CursorKind.get_all_kinds() to retrieve all kinds and see that when using the node.type does not appear in any of them.

function_calls = []           
function_declarations = []     
def traverse(node):

    for child in node.get_children():
        traverse(child)

    if node.kind == clang.cindex.CursorKind.CALL_EXPR:
        function_calls.append(node)

    if node.kind == clang.cindex.CursorKind.FUNCTION_DECL:
        function_declarations.append(node)


    print 'Found %s [line=%s, col=%s]' % (node.displayname, node.location.line, node.location.column)

clang.cindex.Config.set_library_path("/Users/tomgong/Desktop/build/lib")
index = clang.cindex.Index.create()

tu = index.parse(sys.argv[1])

root = tu.cursor        
traverse(root)

Answer 2

I have been using pycparser in order to do obtain the AST of C/C++ source code and explore the same using python.

You can find the API for exploring the AST in this example from the repository.