getMethodName

/*
                             DON'T TELL I DID IT PUBLIC LICENCE

    Everyone is permitted to copy and distribute verbatim copies of this licence document,
    and changing it is allowed as long as the name is changed.

                             DON'T TELL I DID IT PUBLIC LICENCE
               TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION

    0. You may copy, modify and distribute this program under source form and binary form
       as long as you DO NOT include the name of the original author with it.

    1. THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW. THE
    PROGRAM IS PROVIDED “AS IS” WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED,
    INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
    A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM
    IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY
    SERVICING, REPAIR OR CORRECTION.
*/

#include <dlfcn.h>

template<typename T>
const void* voidify(T method)
{
    void* pointer;
    asm ("movq %rdi, -8(%rbp)");
    return pointer;
}

template<typename T, typename M>
const char* getMethodName(const T* object, M method)
{
    Dl_info info;
    const void* methodPointer;

    if (sizeof method == 8) methodPointer = voidify(method); // actual method pointer
    else // vtable entry
    {
        struct VTableEntry
        {
            unsigned long long __pfn;
            unsigned long long __delta;
        };
        const VTableEntry* entry = static_cast<const VTableEntry*>(voidify(&method));
        const void* const* vtable = *(const void* const* const* const)object;
        methodPointer = vtable[(entry->__pfn - 1) / sizeof(void*)];
    }

    if (dladdr(voidify(methodPointer), &info))
        return info.dli_sname;
    return NULL;
}