fp unwind

int xc_test_call_2(int v) {
   //略
}

int xc_test_call_1(void) {
    int r = xc_test_call_2(1);
    return r;
}

int main(int argc, const char * argv[]) {
    int r = xc_test_call_1();
    return (0);
}

main`main:
->  0x100003b9c <+0>:  sub    sp, sp, #0x30
    0x100003ba0 <+4>:  stp    x29, x30, [sp, #0x20]
    0x100003ba4 <+8>:  add    x29, sp, #0x20
    0x100003ba8 <+12>: mov    w8, #0x0
    0x100003bac <+16>: str    w8, [sp, #0x8]
    0x100003bb0 <+20>: stur   wzr, [x29, #-0x4]
    0x100003bb4 <+24>: stur   w0, [x29, #-0x8]
    0x100003bb8 <+28>: str    x1, [sp, #0x10]
    0x100003bbc <+32>: bl     0x100003b74               ; xc_test_call_1 at main.m:51
    0x100003bc0 <+36>: mov    x8, x0
    0x100003bc4 <+40>: ldr    w0, [sp, #0x8]
    0x100003bc8 <+44>: str    w8, [sp, #0xc]
    0x100003bcc <+48>: ldp    x29, x30, [sp, #0x20]
    0x100003bd0 <+52>: add    sp, sp, #0x30
    0x100003bd4 <+56>: ret    

main`xc_test_call_1:
->  0x100003b74 <+0>:  sub    sp, sp, #0x20
    0x100003b78 <+4>:  stp    x29, x30, [sp, #0x10]
    0x100003b7c <+8>:  add    x29, sp, #0x10
    0x100003b80 <+12>: mov    w0, #0x1
    0x100003b84 <+16>: bl     0x100003b44               ; xc_test_call_2 at main.m:46
    0x100003b88 <+20>: stur   w0, [x29, #-0x4]
    0x100003b8c <+24>: ldur   w0, [x29, #-0x4]
    0x100003b90 <+28>: ldp    x29, x30, [sp, #0x10]
    0x100003b94 <+32>: add    sp, sp, #0x20
    0x100003b98 <+36>: ret    

__attribute__((no_sanitize("address", "hwaddress"))) size_t android_unsafe_frame_pointer_chase(
    uintptr_t* buf, size_t num_entries) {
  // Disable MTE checks for the duration of this function, since we can't be sure that following
  // next_frame pointers won't cause us to read from tagged memory. ASAN/HWASAN are disabled here
  // for the same reason.
  ScopedDisableMTE x;

  struct frame_record {
    uintptr_t next_frame, return_addr;
  };

  auto begin = reinterpret_cast<uintptr_t>(__builtin_frame_address(0));
  auto end = __get_thread_stack_top();

  stack_t ss;
  if (sigaltstack(nullptr, &ss) == 0 && (ss.ss_flags & SS_ONSTACK)) {
    end = reinterpret_cast<uintptr_t>(ss.ss_sp) + ss.ss_size;
  }

  size_t num_frames = 0;
  while (1) {
#if defined(__riscv)
    // Frame addresses seem to have been implemented incorrectly for RISC-V.
    // See https://reviews.llvm.org/D87579. We did at least manage to get this
    // documented in the RISC-V psABI though:
    // https://github.com/riscv-non-isa/riscv-elf-psabi-doc/blob/master/riscv-cc.adoc#frame-pointer-convention
    auto* frame = reinterpret_cast<frame_record*>(begin - 16);
#else
    auto* frame = reinterpret_cast<frame_record*>(begin);
#endif
    if (num_frames < num_entries) {
      uintptr_t addr = __bionic_clear_pac_bits(frame->return_addr);
      if (addr == 0) {
        break;
      }
      buf[num_frames] = addr;
    }
    ++num_frames;
    if (frame->next_frame < begin + sizeof(frame_record) || frame->next_frame >= end ||
        frame->next_frame % sizeof(void*) != 0) {
      break;
    }
    begin = frame->next_frame;
  }

  return num_frames;
}

pthread_attr_t attr;
pthread_getattr_np(pthread_self(), &attr);
thread_stack_high = (uintptr_t) (attr.stack_base) + attr.stack_size;
thread_stack_low = (uintptr_t) (attr.stack_base);