Snippet for creating a clang TranslationUnit in python by calling clang as a subprocess instead of parsing with Index.parse

clang_tu_from_ast.py

import subprocess
import tempfile

import clang.cindex as clang

def create_translation_unit_with_ast(source_file_path, clang_args=[], clang_exe='clang'):
    """
    Create a `clang.TranslationUnit` for a source file by compiling it with clang as a
    subprocess instead of using `clang.Index.parse`.

    By doing this, clang will dump its errors directly to stderr, which is very nice for
    oneshot scripts. Also, standard includes like `stddef.h` and `stdbool.h` are handled
    correctly and we don't have to pass them like `-I/path/to/clang/includes` manually
    or after parsing the output from `clang -v -E -` or the like.

    Parameters
    ----------
    source_file_path:
        Path to the input source file. If you want to parse more files, create a new one
        and `#include<>` all of them.
    clang_args:
        Iterable with additional arguments to clang, e.g.: `-I...` or `-D...`
    clang_exe:
        Path for the clang executable, defaults to "clang".
    """
    index = clang.Index.create()
    clang_cmd = [clang_exe, source_file_path, '-emit-ast', '-o', '-']
    clang_cmd.extend(clang_args)
    clang_cmd_result = subprocess.run(clang_cmd, stdout=subprocess.PIPE)
    # In case of errors, raise `CalledProcessError`. Notice that since we didn't
    # redirect clang's stderr, the error was already printed to stderr.
    clang_cmd_result.check_returncode()
    with tempfile.NamedTemporaryFile() as ast_file:
        # Since `clang.Index.read` expects a file path, write generated AST to a
        # temporary named file. This file will be automatically deleted when closed.
        ast_file.write(clang_cmd_result.stdout)
        return index.read(ast_file.name)