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 // This file implements the functionality associated with the terminate_handler,
9 // unexpected_handler, and new_handler.
10 //===----------------------------------------------------------------------===//
11 
12 #include <stdexcept>
13 #include <new>
14 #include <exception>
15 #include "abort_message.h"
16 #include "cxxabi.h"
17 #include "cxa_handlers.h"
18 #include "cxa_exception.h"
19 #include "private_typeinfo.h"
20 #include "include/atomic_support.h" // from libc++
21 
22 namespace std
23 {
24 
25 unexpected_handler
26 get_unexpected() noexcept
27 {
28     return __libcpp_atomic_load(&__cxa_unexpected_handler, _AO_Acquire);
29 }
30 
31 void
32 __unexpected(unexpected_handler func)
33 {
34     func();
35     // unexpected handler should not return
36     abort_message("unexpected_handler unexpectedly returned");
37 }
38 
39 __attribute__((noreturn))
40 void
41 unexpected()
42 {
43     __unexpected(get_unexpected());
44 }
45 
46 terminate_handler
47 get_terminate() noexcept
48 {
49     return __libcpp_atomic_load(&__cxa_terminate_handler, _AO_Acquire);
50 }
51 
52 void
53 __terminate(terminate_handler func) noexcept
54 {
55 #ifndef _LIBCXXABI_NO_EXCEPTIONS
56     try
57     {
58 #endif // _LIBCXXABI_NO_EXCEPTIONS
59         func();
60         // handler should not return
61         abort_message("terminate_handler unexpectedly returned");
62 #ifndef _LIBCXXABI_NO_EXCEPTIONS
63     }
64     catch (...)
65     {
66         // handler should not throw exception
67         abort_message("terminate_handler unexpectedly threw an exception");
68     }
69 #endif // _LIBCXXABI_NO_EXCEPTIONS
70 }
71 
72 __attribute__((noreturn))
73 void
74 terminate() noexcept
75 {
76 #ifndef _LIBCXXABI_NO_EXCEPTIONS
77     // If there might be an uncaught exception
78     using namespace __cxxabiv1;
79     __cxa_eh_globals* globals = __cxa_get_globals_fast();
80     if (globals)
81     {
82         __cxa_exception* exception_header = globals->caughtExceptions;
83         if (exception_header)
84         {
85             _Unwind_Exception* unwind_exception =
86                 reinterpret_cast<_Unwind_Exception*>(exception_header + 1) - 1;
87             if (__isOurExceptionClass(unwind_exception))
88                 __terminate(exception_header->terminateHandler);
89         }
90     }
91 #endif
92     __terminate(get_terminate());
93 }
94 
95 new_handler
96 get_new_handler() noexcept
97 {
98     return __libcpp_atomic_load(&__cxa_new_handler, _AO_Acquire);
99 }
100 
101 }  // std
102