You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: gcc.rs
    path of file: ./repos/incubator-teaclave-sgx-sdk/sgx_panic_unwind/src
    
    the code of the file until where you have to start completion: //! Implementation of panics backed by libgcc/libunwind (in some form).
//!
//! For background on exception handling and stack unwinding please see
//! "Exception Handling in LLVM" (llvm.org/docs/ExceptionHandling.html) and
//! documents linked from it.
//! These are also good reads:
    
pub unsafe fn cleanup(ptr: *mut u8) -> Box<dyn Any + Send> {
    let exception = ptr as *mut uw::_Unwind_Exception;
    if (*exception).exception_class != rust_exception_class() {
        uw::_Unwind_DeleteException(exception);
        super::__rust_foreign_exception();
    } else {
        let exception = Box::from_raw(exception as *mut Exception);
        exception.cause
    }
}