I have the following script that attempts to print out all the AST nodes in a given C++ file. This works fine when using it on a simple file with trivial includes (header file in the same directory, etc).
#!/usr/bin/env python from argparse import ArgumentParser, FileType from clang import cindex def node_info(node): return {'kind': node.kind, 'usr': node.get_usr(), 'spelling': node.spelling, 'location': node.location, 'file': node.location.file.name, 'extent.start': node.extent.start, 'extent.end': node.extent.end, 'is_definition': node.is_definition() } def get_nodes_in_file(node, filename, ls=None): ls = ls if ls is not None else [] for n in node.get_children(): if n.location.file is not None and n.location.file.name == filename: ls.append(n) get_nodes_in_file(n, filename, ls) return ls def main(): arg_parser = ArgumentParser() arg_parser.add_argument('source_file', type=FileType('r+'), help='C++ source file to parse.') arg_parser.add_argument('compilation_database', type=FileType('r+'), help='The compile_commands.json to use to parse the source file.') args = arg_parser.parse_args() compilation_database_path = args.compilation_database.name source_file_path = args.source_file.name clang_args = ['-x', 'c++', '-std=c++11', '-p', compilation_database_path] index = cindex.Index.create() translation_unit = index.parse(source_file_path, clang_args) file_nodes = get_nodes_in_file(translation_unit.cursor, source_file_path) print [p.spelling for p in file_nodes] if __name__ == '__main__': main()
However, I get a clang.cindex.TranslationUnitLoadError: Error parsing translation unit.
when I run the script and provide a valid C++ file that has a compile_commands.json file in its parent directory. This code runs and builds fine using CMake with clang, but I can’t seem to figure out how to pass the argument for pointing to the compile_commands.json correctly.
I also had difficulty finding this option in the clang documentation and could not get -ast-dump
to work. However, clang-check works fine by just passing the file path!
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Answer
Your own accepted answer is incorrect. libclang
does support compilation databases and so does cindex.py, the libclang python binding.
The main source of confusion might be that the compilation flags that libclang knows/uses are only a subset of all arguments that can be passed to the clang frontend. The compilation database is supported but does not work automatically: it must be loaded and queried manually. Something like this should work:
#!/usr/bin/env python from argparse import ArgumentParser, FileType from clang import cindex compilation_database_path = args.compilation_database.name source_file_path = args.source_file.name index = cindex.Index.create() # Step 1: load the compilation database compdb = cindex.CompilationDatabase.fromDirectory(compilation_database_path) # Step 2: query compilation flags try: file_args = compdb.getCompileCommands(source_file_path) translation_unit = index.parse(source_file_path, file_args) file_nodes = get_nodes_in_file(translation_unit.cursor, source_file_path) print [p.spelling for p in file_nodes] except CompilationDatabaseError: print 'Could not load compilation flags for', source_file_path