#include <stdint.h>

__attribute__((__visibility__("hidden"))) void* __fdpic_fixup(void* map, uintptr_t* a,
                                                              uintptr_t* z) {
    /* If map is a null pointer, the program was loaded by a
     * non-FDPIC-aware ELF loader, and fixups are not needed,
     * but the value for the GOT pointer is. */
    if (!map)
        return (void*)z[-1];

    struct {
        unsigned short version, nsegs;
        struct fdpic_loadseg {
            uintptr_t addr, p_vaddr, p_memsz;
        } segs[];
    }* lm = map;
    int nsegs = lm->nsegs, rseg = 0, vseg = 0;
    for (;;) {
        while (*a - lm->segs[rseg].p_vaddr >= lm->segs[rseg].p_memsz)
            if (++rseg == nsegs)
                rseg = 0;
        uintptr_t* r = (uintptr_t*)(*a + lm->segs[rseg].addr - lm->segs[rseg].p_vaddr);
        if (++a == z)
            return r;
        while (*r - lm->segs[vseg].p_vaddr >= lm->segs[vseg].p_memsz)
            if (++vseg == nsegs)
                vseg = 0;
        *r += lm->segs[vseg].addr - lm->segs[vseg].p_vaddr;
    }
}