Measuring exception handling overhead in C++

g++ exception_handling.cpp -o exception_handling [ -O2 ]

g++ exception_handling.cpp -o exception_handling [ -O2 ] -fno-exceptions -DNO_EXCEPTIONS

#include <stdio.h>

// Timer code

#if defined(__linux__)
#include <sys/time.h>
#include <time.h>

double time()
{
    timeval tv;
    gettimeofday(&tv, 0);
    return 1.0 * tv.tv_sec + 0.000001 * tv.tv_usec;
}
#elif defined(_WIN32)
#include <windows.h>

double get_performance_frequency()
{
    unsigned _int64 frequency;
    QueryPerformanceFrequency((LARGE_INTEGER*) &frequency); // just assume it works
    return double(frequency);
}

double performance_frequency = get_performance_frequency();

double time()
{
    unsigned _int64 counter;
    QueryPerformanceCounter((LARGE_INTEGER*) &counter);
    return double(counter) / performance_frequency;
}
#else
# error time() not implemented for your platform
#endif

// How many times to repeat the whole test
const int repeats = 10;

// How many times to iterate one case
const int times = 1000000;

// Trick optimizer to not remove code
int result = 0;



// Case 1. No exception thrown nor handled.

void do_something()
{
    ++result;
}

void case1()
{
    do_something();
}



// Case 2. No exception thrown, but handler installed

#ifndef NO_EXCEPTIONS
void do_something_else()
{
    --result;
}

void case2()
{
    try
    {
        do_something();
    }
    catch (int exception)
    {
        do_something_else();
    }
}



// Case 3. Exception thrown and caught

void do_something_and_throw()
{
    throw ++result;
}

void case3()
{
    try
    {
        do_something_and_throw();
    }
    catch (int exception)
    {
        result = exception;
    }
}
#endif // !NO_EXCEPTIONS

void (*tests[])() =
{
    case1,
#ifndef NO_EXCEPTIONS
    case2,
    case3
#endif // !NO_EXCEPTIONS
};

int main()
{
#ifdef NO_EXCEPTIONS
    printf("case0n");
#else
    printf("case1tcase2tcase3n");
#endif
    for (int repeat = 0; repeat < repeats; ++repeat)
    {
        for (int test = 0; test < sizeof(tests)/sizeof(tests[0]); ++test)
        {
            double start = time();

            for (int i = 0; i < times; ++i)
                tests[test]();

            double end = time();

            printf("%ft", (end - start) * 1000000.0 / times);
        }
        printf("n");
    }

    return result; // optimizer is happy - we produce a result
}