Demangle C++ symbols using LLVM's IA-64 C++ ABI demangler.

pycxxfilt is a Python C extension that wraps the C++ name demangler from LLVM's libcxxabi. It handles the name mangling scheme defined by the Itanium C++ ABI, which is the standard used by GCC (3.0+), Clang (1.0+), and other compilers on most platforms. The demangler source is shipped directly, so no external C++ libraries are required at build time or runtime.

pip install pycxxfilt

Wheels are available for Linux (x86_64, aarch64, ppc64le, s390x), macOS (x86_64, arm64), and Windows (AMD64). The extension uses the Python stable ABI (abi3), so a single wheel works with Python 3.11 and later.

import pycxxfilt

pycxxfilt.demangle("_Z3fooi")          # 'foo(int)'
pycxxfilt.demangle("_ZN3Foo3barEv")    # 'Foo::bar()'
pycxxfilt.demangle("_ZSt4cout")        # 'std::cout'
pycxxfilt.demangle("not_mangled")      # None

demangle() returns the demangled name as a string, or None if the input is not a valid mangled symbol.

$ python -m pycxxfilt _Z3fooi _ZN3Foo3barEv _ZSt4cout not_mangled
foo(int)
Foo::bar()
std::cout
not_mangled

Symbols that are not valid mangled names are printed as-is.

The cxxfilt package uses ctypes to call __cxa_demangle from the system's libstdc++.so. This means it depends on a C++ runtime library being installed and available at runtime, and it is not available on Windows.

pycxxfilt takes a different approach: it ships a vendored copy of LLVM's __cxa_demangle implementation and compiles it into a C extension module. This makes it self-contained with no runtime dependency on any system C++ library, and it works on Linux, macOS, and Windows.

The project code is licensed under the Apache License 2.0.

The vendored LLVM demangler is licensed under the Apache License 2.0 with LLVM Exceptions.