1 //===------------------------- cxa_default_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 default terminate_handler and unexpected_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.hpp"
18 #include "cxa_exception.hpp"
19 #include "private_typeinfo.h"
20 
21 static const char* cause = "uncaught";
22 
23 __attribute__((noreturn))
24 static void default_terminate_handler()
25 {
26     // If there might be an uncaught exception
27     using namespace __cxxabiv1;
28     __cxa_eh_globals* globals = __cxa_get_globals_fast();
29     if (globals)
30     {
31         __cxa_exception* exception_header = globals->caughtExceptions;
32         // If there is an uncaught exception
33         if (exception_header)
34         {
35             _Unwind_Exception* unwind_exception =
36                 reinterpret_cast<_Unwind_Exception*>(exception_header + 1) - 1;
37             bool native_exception =
38                 (unwind_exception->exception_class   & get_vendor_and_language) ==
39                                  (kOurExceptionClass & get_vendor_and_language);
40             if (native_exception)
41             {
42                 void* thrown_object =
43                     unwind_exception->exception_class == kOurDependentExceptionClass ?
44                         ((__cxa_dependent_exception*)exception_header)->primaryException :
45                         exception_header + 1;
46                 const __shim_type_info* thrown_type =
47                     static_cast<const __shim_type_info*>(exception_header->exceptionType);
48                 // Try to get demangled name of thrown_type
49                 int status;
50                 char buf[1024];
51                 size_t len = sizeof(buf);
52                 const char* name = __cxa_demangle(thrown_type->name(), buf, &len, &status);
53                 if (status != 0)
54                     name = thrown_type->name();
55                 // If the uncaught exception can be caught with std::exception&
56                 const __shim_type_info* catch_type =
57 				 static_cast<const __shim_type_info*>(&typeid(std::exception));
58                 if (catch_type->can_catch(thrown_type, thrown_object))
59                 {
60                     // Include the what() message from the exception
61                     const std::exception* e = static_cast<const std::exception*>(thrown_object);
62                     abort_message("terminating with %s exception of type %s: %s",
63                                   cause, name, e->what());
64                 }
65                 else
66                     // Else just note that we're terminating with an exception
67                     abort_message("terminating with %s exception of type %s",
68                                    cause, name);
69             }
70             else
71                 // Else we're terminating with a foreign exception
72                 abort_message("terminating with %s foreign exception", cause);
73         }
74     }
75     // Else just note that we're terminating
76     abort_message("terminating");
77 }
78 
79 __attribute__((noreturn))
80 static void default_unexpected_handler()
81 {
82     cause = "unexpected";
83     std::terminate();
84 }
85 
86 
87 //
88 // Global variables that hold the pointers to the current handler
89 //
90 std::terminate_handler  __cxa_terminate_handler = default_terminate_handler;
91 std::unexpected_handler __cxa_unexpected_handler = default_unexpected_handler;
92 
93 // In the future these will become:
94 // std::atomic<std::terminate_handler>  __cxa_terminate_handler(default_terminate_handler);
95 // std::atomic<std::unexpected_handler> __cxa_unexpected_handler(default_unexpected_handler);
96 
97 namespace std
98 {
99 
100 unexpected_handler
101 set_unexpected(unexpected_handler func) _NOEXCEPT
102 {
103 	if (func == 0)
104 		func = default_unexpected_handler;
105 	return __sync_swap(&__cxa_unexpected_handler, func);
106 //  Using of C++11 atomics this should be rewritten
107 //  return __cxa_unexpected_handler.exchange(func, memory_order_acq_rel);
108 }
109 
110 terminate_handler
111 set_terminate(terminate_handler func) _NOEXCEPT
112 {
113 	if (func == 0)
114 		func = default_terminate_handler;
115 	return __sync_swap(&__cxa_terminate_handler, func);
116 //  Using of C++11 atomics this should be rewritten
117 //  return __cxa_terminate_handler.exchange(func, memory_order_acq_rel);
118 }
119 
120 }
121