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 <dlfcn.h>
15 #include <stdlib.h>
16 #include <string.h>
17 #include <unwind.h>
18 
19 _Unwind_Reason_Code frame_handler(struct _Unwind_Context *ctx, void *arg) {
20   (void)arg;
21   Dl_info info = {0, 0, 0, 0};
22 
23   // Unwind util the main is reached, above frames depend on the platform and
24   // architecture.
25   if (dladdr(reinterpret_cast<void *>(_Unwind_GetIP(ctx)), &info) &&
26       info.dli_sname && !strcmp("main", info.dli_sname))
27     _Exit(0);
28 
29   return _URC_NO_REASON;
30 }
31 
32 __attribute__((noinline)) void foo() {
33   // Provide some CFI directives that instructs the unwinder where given
34   // float register is.
35 #if defined(__aarch64__)
36   // DWARF register number for V0-V31 registers are 64-95.
37   // Previous value of V0 is saved at offset 0 from CFA.
38   asm volatile(".cfi_offset 64, 0");
39   // From now on the previous value of register can't be restored anymore.
40   asm volatile(".cfi_undefined 65");
41   asm volatile(".cfi_undefined 95");
42   // Previous value of V2 is in V30.
43   asm volatile(".cfi_register  66, 94");
44 #endif
45   _Unwind_Backtrace(frame_handler, NULL);
46 }
47 
48 int main() {
49   foo();
50   return -2;
51 }
52