zircon/third_party/ulib/musl/ldso/relr.h

// Copyright 2018 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "dynlink.h"

LIBC_NO_SAFESTACK NO_ASAN static inline void apply_relr(ElfW(Addr) base, const ElfW(Addr) * relr,
                                                        size_t relrsz) {
  const size_t nrelr = relrsz / sizeof(relr[0]);
  size_t i = 0;
  while (i < nrelr) {
    ElfW(Addr)* addr = (void*)(base + relr[i++]);
    *addr++ += base;
    while (i < nrelr && (relr[i] & 1)) {
      // Each bitmask word covers the next 63 possible relocations.
      // Each bit is one if run[bit] should be relocated.

      ElfW(Addr)* run = addr;
      addr += (sizeof(relr[0]) * CHAR_BIT) - 1;

      int skip;
      for (ElfW(Addr) bitmask = relr[i++] >> 1; bitmask != 0; bitmask >>= skip) {
        skip = __builtin_ctzl(bitmask) + 1;
        run += skip;
        run[-1] += base;
      }
    }
  }
}