Mach-O vs. ELF export benchmark

exe.c

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <time.h>

#include <dlfcn.h>
#include <err.h>

#define NSYMS 1000000

#if __linux__
#define LIB_EXT "so"
#elif __APPLE__
#define LIB_EXT "dylib"
#else
#error "huh?"
#endif

struct sym {
    char* good_name;
    char* bad_name;
    int res;
};

struct sym syms[NSYMS] = {
#include "syms.inc"
};

int main(int argc, char* argv[]) {
    if (argc != 2) {
        err(1, "Usage: %s good|bad", argv[0]);
    }

    void* lib = dlopen("./lib." LIB_EXT, RTLD_NOW);
    if (lib == NULL) {
        err(1, "dlopen: %s", dlerror());
    }

    if (strcmp(argv[1], "good") == 0) {
        clock_t good_start = clock();
        for (size_t ii = 0; ii < NSYMS; ++ii) {
            int(*f)() = dlsym(lib, syms[ii].good_name);
            if (f == NULL) {
                err(1, "%s: %s", syms[ii].good_name, dlerror());
            }
            int actual_val = f();
            if (actual_val != syms[ii].res) {
                err(1, "mismatch: %d vs. %d", actual_val, syms[ii].res);
            }
        }
        clock_t good_end = clock();
        printf("Good syms: %.2fms\n", (good_end - good_start) / (double)CLOCKS_PER_SEC * 1e3);
    } else if (strcmp(argv[1], "bad") == 0) {
        clock_t bad_start = clock();
        for (size_t ii = 0; ii < NSYMS; ++ii) {
            int(*f)() = dlsym(lib, syms[ii].bad_name);
            if (f != NULL) {
                err(1, "%s was somehow found", syms[ii].bad_name);
            }
        }
        clock_t bad_end = clock();
        printf("Bad syms: %.2fms\n", (bad_end - bad_start) / (double)CLOCKS_PER_SEC * 1e3);
    } else {
        err(1, "Unknown mode: %s", argv[1]);
    }

    return 0;
}

gen_lib.py

import string
import random


def random_snake_case():
    return '_'.join(
        ''.join(random.choices(
            string.ascii_lowercase,
            k=random.randint(5, 15)
        ))
        for ii in range(random.randint(2, 5))
    )


def random_camel_case():
    return ''.join(
        random.choice(string.ascii_uppercase) + ''.join(random.choices(
            string.ascii_lowercase,
            k=random.randint(5, 15),
        ))
        for ii in range(random.randint(2, 5))
    )


if __name__ == '__main__':
    random.seed(42)
    N = 1_000_000

    func_names = [
        (ii, random_camel_case() if ii % 2 == 0 else random_snake_case())
        for ii in range(N)
    ]

    with open('lib.c', 'w') as f:
        for ii, func_name in func_names:
            print(
f'''int {func_name}() {{
    return {ii};
}}'''
            , file=f)

    random.shuffle(func_names)
    with open('syms.inc', 'w') as f:
        for ii, func_name in func_names:
            bad_name = func_name[:-1] + chr(ord(func_name[-1]) + 1)
            print(f'{{.good_name = "{func_name}", .bad_name = "{bad_name}", .res = {ii}}},', file=f)