Hello World JIT for Apple Silicon

jitted.c

#include <pthread.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdint.h>
#include <string.h>
#include <sys/mman.h>

static uint8_t code[] = {
  0x40, 0x05, 0x80, 0x52, // mov w0, #3
  0xc0, 0x03, 0x5f, 0xd6, // ret
};

int main(int argc, const char * argv[]) {
  const int size = sizeof(code);

  int map_flags = MAP_ANON | MAP_PRIVATE | MAP_JIT;

  void* mem = (int *)mmap(NULL, size, PROT_READ | PROT_WRITE | PROT_EXEC, map_flags, -1, 0);

  if (mem == MAP_FAILED || mem == NULL) {
    printf("Failed to allocate executable memory\n");
    return 1;
  }

  pthread_jit_write_protect_np(false);
  memcpy(mem, code, size);
  pthread_jit_write_protect_np(true);

  int (*jitted_function)(void) = (int (*)(void))mem;
  printf("JIT-ed code returned: %d\n", jitted_function());

  return 0;
}