Template

#include <stdio.h>
#include <stdint.h>

//-------------------------------------------------------------//
// "Malware related compile-time hacks with C++11" by LeFF   //
// You can use this code however you like, I just don't really //
// give a shit, but if you feel some respect for me, please //
// don't cut off this comment when copy-pasting... ;-)       //
//-------------------------------------------------------------//

// Usage examples:
void exampleRandom1()   __attribute__((noinline));
void exampleRandom2()   __attribute__((noinline));
void exampleHashing()   __attribute__((noinline));
void exampleEncryption() __attribute__((noinline));

#ifndef vxCPLSEED
    // If you don't specify the seed for algorithms, the time when compilation
    // started will be used, seed actually changes the results of algorithms...
    #define vxCPLSEED ((__TIME__[7] - '0') * 1  + (__TIME__[6] - '0') * 10  + \
                       (__TIME__[4] - '0') * 60   + (__TIME__[3] - '0') * 600 + \
                       (__TIME__[1] - '0') * 3600 + (__TIME__[0] - '0') * 36000)
#endif

// The constantify template is used to make sure that the result of constexpr
// function will be computed at compile-time instead of run-time
template <uint32_t Const> struct vxCplConstantify { enum { Value = Const }; };

// Compile-time mod of a linear congruential pseudorandom number generator,
// the actual algorithm was taken from "Numerical Recipes" book
constexpr uint32_t vxCplRandom(uint32_t Id)
{ return (1013904223 + 1664525 * ((Id > 0) ? (vxCplRandom(Id - 1)) : (vxCPLSEED))) & 0xFFFFFFFF; }

// Compile-time random macros, can be used to randomize execution
// path for separate builds, or compile-time trash code generation
#define vxRANDOM(Min, Max) (Min + (vxRAND() % (Max - Min + 1)))
#define vxRAND()           (vxCplConstantify<vxCplRandom(__COUNTER__ + 1)>::Value)

// Compile-time recursive mod of string hashing algorithm,
// the actual algorithm was taken from Qt library (this
// function isn't case sensitive due to vxCplTolower)
constexpr char   vxCplTolower(char Ch)                { return (Ch >= 'A' && Ch <= 'Z') ? (Ch - 'A' + 'a') : (Ch); }
constexpr uint32_t vxCplHashPart3(char Ch, uint32_t Hash) { return ((Hash << 4) + vxCplTolower(Ch)); }
constexpr uint32_t vxCplHashPart2(char Ch, uint32_t Hash) { return (vxCplHashPart3(Ch, Hash) ^ ((vxCplHashPart3(Ch, Hash) & 0xF0000000) >> 23)); }
constexpr uint32_t vxCplHashPart1(char Ch, uint32_t Hash) { return (vxCplHashPart2(Ch, Hash) & 0x0FFFFFFF); }
constexpr uint32_t vxCplHash(const char* Str)            { return (*Str) ? (vxCplHashPart1(*Str, vxCplHash(Str + 1))) : (0); }

// Compile-time hashing macro, hash values changes using the first pseudorandom number in sequence
#define vxHASH(Str) (uint32_t)(vxCplConstantify<vxCplHash(Str)>::Value ^ vxCplConstantify<vxCplRandom(1)>::Value)

// Compile-time generator for list of indexes (0, 1, 2, ...)
template <uint32_t...> struct vxCplIndexList {};
template <typename   IndexList, uint32_t Right> struct vxCplAppend;
template <uint32_t... Left,    uint32_t Right> struct vxCplAppend<vxCplIndexList<Left...>, Right> { typedef vxCplIndexList<Left..., Right> Result; };
template <uint32_t N> struct vxCplIndexes { typedef typename vxCplAppend<typename vxCplIndexes<N - 1>::Result, N - 1>::Result Result; };
template <> struct vxCplIndexes<0> { typedef vxCplIndexList<> Result; };

// Compile-time string encryption of a single character
const char vxCplEncryptCharKey = vxRANDOM(0, 0xFF);
constexpr char vxCplEncryptChar(const char Ch, uint32_t Idx) { return Ch ^ (vxCplEncryptCharKey + Idx); }

// Compile-time string encryption class
template <typename IndexList> struct vxCplEncryptedString;
template <uint32_t... Idx>    struct vxCplEncryptedString<vxCplIndexList<Idx...> >
{
    char Value[sizeof...(Idx) + 1]; // Buffer for a string

    // Compile-time constructor
    constexpr inline vxCplEncryptedString(const char* const Str)
    : Value({ vxCplEncryptChar(Str[Idx], Idx)... }) {}

    // Run-time decryption
    char* decrypt()
    {
        for(uint32_t t = 0; t < sizeof...(Idx); t++)
        { this->Value[t] = this->Value[t] ^ (vxCplEncryptCharKey + t); }
        this->Value[sizeof...(Idx)] = '\0'; return this->Value;
    }
};

// Compile-time string encryption macro
#define vxENCRYPT(Str) (vxCplEncryptedString<vxCplIndexes<sizeof(Str) - 1>::Result>(Str).decrypt())

// A small random code path example
void exampleRandom1()
{
    switch(vxRANDOM(1, 4))
    {
        case 1:  { printf("exampleRandom1: Code path 1!\n"); break; }
        case 2:  { printf("exampleRandom1: Code path 2!\n"); break; }
        case 3:  { printf("exampleRandom1: Code path 3!\n"); break; }
        case 4:  { printf("exampleRandom1: Code path 4!\n"); break; }
        default: { printf("Fucking poltergeist!\n"); }
    }
}

// A small random code generator example
void exampleRandom2()
{
    volatile uint32_t RndVal = vxRANDOM(0, 100);
    if(vxRAND() % 2) { RndVal += vxRANDOM(0, 100); }
    else             { RndVal -= vxRANDOM(0, 200); }
    printf("exampleRandom2: %d\n", RndVal);
}

// A small string hasing example
void exampleHashing()
{
    printf("exampleHashing: 0x%08X\n", vxHASH("hello world!"));
    printf("exampleHashing: 0x%08X\n", vxHASH("HELLO WORLD!"));
}

void exampleEncryption()
{
    printf("exampleEncryption: %s\n", vxENCRYPT("Hello world!"));
}

extern "C" void Main()
{
    exampleRandom1();
    exampleRandom2();
    exampleHashing();
    exampleEncryption();
}


To build code with GCC/MinGW:
g++ -o main.exe -m32 -std=c++0x -Wall -O3 -Os -fno-exceptions -fno-rtti -flto -masm=intel -e_Main -nostdlib -O3 -Os -flto -s main.cpp -lmsvcrt