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 // Ensure that leaf function can be unwund.
11 // REQUIRES: linux && (target={{aarch64-.+}} || target={{s390x-.+}} || target={{x86_64-.+}})
12 
13 // TODO: Figure out why this fails with Memory Sanitizer.
14 // XFAIL: msan
15 
16 #include <assert.h>
17 #include <dlfcn.h>
18 #include <signal.h>
19 #include <stdio.h>
20 #include <stdlib.h>
21 #include <string.h>
22 #include <sys/types.h>
23 #include <unistd.h>
24 #include <unwind.h>
25 
26 _Unwind_Reason_Code frame_handler(struct _Unwind_Context* ctx, void* arg) {
27   (void)arg;
28   Dl_info info = { 0, 0, 0, 0 };
29 
30   // Unwind util the main is reached, above frames deeped on the platfrom and architecture.
31   if (dladdr(reinterpret_cast<void *>(_Unwind_GetIP(ctx)), &info) &&
32       info.dli_sname && !strcmp("main", info.dli_sname)) {
33     _Exit(0);
34   }
35   return _URC_NO_REASON;
36 }
37 
38 void signal_handler(int signum) {
39   (void)signum;
40   _Unwind_Backtrace(frame_handler, NULL);
41   _Exit(-1);
42 }
43 
44 __attribute__((noinline)) void crashing_leaf_func(void) {
45   // libunwind searches for the address before the return address which points
46   // to the trap instruction. NOP guarantees the trap instruction is not the
47   // first instruction of the function.
48   // We should keep this here for other unwinders that also decrement pc.
49   __asm__ __volatile__("nop");
50   __builtin_trap();
51 }
52 
53 int main(int, char**) {
54   signal(SIGTRAP, signal_handler);
55   signal(SIGILL, signal_handler);
56   crashing_leaf_func();
57   return -2;
58 }
59