1 //===------------------------- cxa_handlers.cpp ---------------------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is dual licensed under the MIT and the University of Illinois Open
6 // Source Licenses. See LICENSE.TXT for details.
7 //
8 //
9 // This file implements the functionality associated with the terminate_handler,
10 // unexpected_handler, and new_handler.
11 //===----------------------------------------------------------------------===//
12
13 #include <stdexcept>
14 #include <new>
15 #include <exception>
16 #include "abort_message.h"
17 #include "config.h"
18 #include "cxxabi.h"
19 #include "cxa_handlers.hpp"
20 #include "cxa_exception.hpp"
21 #include "private_typeinfo.h"
22
23 namespace std
24 {
25
26 unexpected_handler
get_unexpected()27 get_unexpected() _NOEXCEPT
28 {
29 return __sync_fetch_and_add(&__cxa_unexpected_handler, (unexpected_handler)0);
30 // The above is safe but overkill on x86
31 // Using of C++11 atomics this should be rewritten
32 // return __cxa_unexpected_handler.load(memory_order_acq);
33 }
34
35 __attribute__((visibility("hidden"), noreturn))
36 void
__unexpected(unexpected_handler func)37 __unexpected(unexpected_handler func)
38 {
39 func();
40 // unexpected handler should not return
41 abort_message("unexpected_handler unexpectedly returned");
42 }
43
44 __attribute__((noreturn))
45 void
unexpected()46 unexpected()
47 {
48 __unexpected(get_unexpected());
49 }
50
51 terminate_handler
get_terminate()52 get_terminate() _NOEXCEPT
53 {
54 return __sync_fetch_and_add(&__cxa_terminate_handler, (terminate_handler)0);
55 // The above is safe but overkill on x86
56 // Using of C++11 atomics this should be rewritten
57 // return __cxa_terminate_handler.load(memory_order_acq);
58 }
59
60 __attribute__((visibility("hidden"), noreturn))
61 void
__terminate(terminate_handler func)62 __terminate(terminate_handler func) _NOEXCEPT
63 {
64 #ifndef _LIBCXXABI_NO_EXCEPTIONS
65 try
66 {
67 #endif // _LIBCXXABI_NO_EXCEPTIONS
68 func();
69 // handler should not return
70 abort_message("terminate_handler unexpectedly returned");
71 #ifndef _LIBCXXABI_NO_EXCEPTIONS
72 }
73 catch (...)
74 {
75 // handler should not throw exception
76 abort_message("terminate_handler unexpectedly threw an exception");
77 }
78 #endif // _LIBCXXABI_NO_EXCEPTIONS
79 }
80
81 __attribute__((noreturn))
82 void
terminate()83 terminate() _NOEXCEPT
84 {
85 // If there might be an uncaught exception
86 using namespace __cxxabiv1;
87 __cxa_eh_globals* globals = __cxa_get_globals_fast();
88 if (globals)
89 {
90 __cxa_exception* exception_header = globals->caughtExceptions;
91 if (exception_header)
92 {
93 _Unwind_Exception* unwind_exception =
94 reinterpret_cast<_Unwind_Exception*>(exception_header + 1) - 1;
95 bool native_exception =
96 (unwind_exception->exception_class & get_vendor_and_language) ==
97 (kOurExceptionClass & get_vendor_and_language);
98 if (native_exception)
99 __terminate(exception_header->terminateHandler);
100 }
101 }
102 __terminate(get_terminate());
103 }
104
105 // In the future this will become:
106 // std::atomic<std::new_handler> __cxa_new_handler(0);
107 extern "C" {
108 _LIBCXXABI_DATA_VIS new_handler __cxa_new_handler = 0;
109 }
110
111 new_handler
set_new_handler(new_handler handler)112 set_new_handler(new_handler handler) _NOEXCEPT
113 {
114 return __atomic_exchange_n(&__cxa_new_handler, handler, __ATOMIC_ACQ_REL);
115 // Using of C++11 atomics this should be rewritten
116 // return __cxa_new_handler.exchange(handler, memory_order_acq_rel);
117 }
118
119 new_handler
get_new_handler()120 get_new_handler() _NOEXCEPT
121 {
122 return __sync_fetch_and_add(&__cxa_new_handler, (new_handler)0);
123 // The above is safe but overkill on x86
124 // Using of C++11 atomics this should be rewritten
125 // return __cxa_new_handler.load(memory_order_acq);
126 }
127
128 } // std
129