demangler

A demangler is a software component or utility that converts mangled symbol names produced by compilers back into human-readable form. Name mangling is used in many programming languages to encode information such as namespaces, classes, function overloading, templates, and other type information into a symbol so that the linker can distinguish between overloads and different scopes.

Demangling works by parsing the mangled string according to the language’s or ABI’s specification and reconstructing a readable signature. Different languages and toolchains define different mangling schemes, so demanglers are typically language- and ABI-specific. Common examples include the Itanium C++ ABI demangler (often accessed via the c++filt tool), MSVC’s demangling used by various Windows tools, and language-specific demanglers such as rust-demangle for Rust, swift-demangle for Swift, and D language demanglers.

In practice, demangling is widely used in debugging and profiling. Debuggers like GDB and LLDB display demangled names in stack traces, crash reports, and symbolication of core dumps. Build systems and IDEs may present readable symbols to developers, and performance profilers can show human-friendly function names.

Limitations exist: a demangler can fail on corrupted or non-standard names, and some information encoded in the mangled form may be lossy or not fully recoverable in a human-friendly way. Nevertheless, demangling remains a key tool for interpreting compiler-generated symbols and understanding program behavior.

---