1// -*- C++ -*-
2//===----------------------------------------------------------------------===//
3//
4// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
5// See https://llvm.org/LICENSE.txt for license information.
6// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7//
8//===----------------------------------------------------------------------===//
9
10// REQUIRES: linux && target={{aarch64-.+}}
11
12// Basic test for float registers number are accepted.
13
14#include <stdlib.h>
15#include <string.h>
16#include <unwind.h>
17
18// Using __attribute__((section("main_func"))) is ELF specific, but then
19// this entire test is marked as requiring Linux, so we should be good.
20//
21// We don't use dladdr() because on musl it's a no-op when statically linked.
22extern char __start_main_func;
23extern char __stop_main_func;
24
25_Unwind_Reason_Code frame_handler(struct _Unwind_Context *ctx, void *arg) {
26 (void)arg;
27
28 // Unwind until the main is reached, above frames depend on the platform and
29 // architecture.
30 uintptr_t ip = _Unwind_GetIP(ctx);
31 if (ip >= (uintptr_t)&__start_main_func &&
32 ip < (uintptr_t)&__stop_main_func) {
33 _Exit(status: 0);
34 }
35
36 return _URC_NO_REASON;
37}
38
39__attribute__((noinline)) void foo() {
40 // Provide some CFI directives that instructs the unwinder where given
41 // float register is.
42#if defined(__aarch64__)
43 // DWARF register number for V0-V31 registers are 64-95.
44 // Previous value of V0 is saved at offset 0 from CFA.
45 asm volatile(".cfi_offset 64, 0");
46 // From now on the previous value of register can't be restored anymore.
47 asm volatile(".cfi_undefined 65");
48 asm volatile(".cfi_undefined 95");
49 // Previous value of V2 is in V30.
50 asm volatile(".cfi_register 66, 94");
51#endif
52 _Unwind_Backtrace(frame_handler, NULL);
53}
54
55__attribute__((section("main_func"))) int main() {
56 foo();
57 return -2;
58}
59

source code of libunwind/test/floatregister.pass.cpp