1 //===----------------------------------------------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 // UNSUPPORTED: no-exceptions
10 
11 #include <assert.h>
12 #include <stddef.h>
13 #include <unwind.h>
14 
15 extern "C" _Unwind_Reason_Code
16 trace_function(struct _Unwind_Context*, void* ntraced) {
17   (*reinterpret_cast<size_t*>(ntraced))++;
18   // We should never have a call stack this deep...
19   assert(*reinterpret_cast<size_t*>(ntraced) < 20);
20   return _URC_NO_REASON;
21 }
22 
23 __attribute__ ((__noinline__))
24 void call3_throw(size_t* ntraced) {
25   try {
26     _Unwind_Backtrace(trace_function, ntraced);
27   } catch (...) {
28     assert(false);
29   }
30 }
31 
32 __attribute__ ((__noinline__, __disable_tail_calls__))
33 void call3_nothrow(size_t* ntraced) {
34   _Unwind_Backtrace(trace_function, ntraced);
35 }
36 
37 __attribute__ ((__noinline__, __disable_tail_calls__))
38 void call2(size_t* ntraced, bool do_throw) {
39   if (do_throw) {
40     call3_throw(ntraced);
41   } else {
42     call3_nothrow(ntraced);
43   }
44 }
45 
46 __attribute__ ((__noinline__, __disable_tail_calls__))
47 void call1(size_t* ntraced, bool do_throw) {
48   call2(ntraced, do_throw);
49 }
50 
51 int main(int, char**) {
52   size_t throw_ntraced = 0;
53   size_t nothrow_ntraced = 0;
54 
55   call1(&nothrow_ntraced, false);
56 
57   try {
58     call1(&throw_ntraced, true);
59   } catch (...) {
60     assert(false);
61   }
62 
63   // Different platforms (and different runtimes) will unwind a different number
64   // of times, so we can't make any better assumptions than this.
65   assert(nothrow_ntraced > 1);
66   assert(throw_ntraced == nothrow_ntraced); // Make sure we unwind through catch
67   return 0;
68 }
69