1 // -*- C++ -*- Exception handling routines for throwing.
2 // Copyright (C) 2001-2018 Free Software Foundation, Inc.
3 //
4 // This file is part of GCC.
5 //
6 // GCC is free software; you can redistribute it and/or modify
7 // it under the terms of the GNU General Public License as published by
8 // the Free Software Foundation; either version 3, or (at your option)
9 // any later version.
10 //
11 // GCC is distributed in the hope that it will be useful,
12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 // GNU General Public License for more details.
15 //
16 // Under Section 7 of GPL version 3, you are granted additional
17 // permissions described in the GCC Runtime Library Exception, version
18 // 3.1, as published by the Free Software Foundation.
19
20 // You should have received a copy of the GNU General Public License and
21 // a copy of the GCC Runtime Library Exception along with this program;
22 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
23 // <http://www.gnu.org/licenses/>.
24
25 #include <bits/c++config.h>
26 #include "unwind-cxx.h"
27 #include "eh_atomics.h"
28
29 using namespace __cxxabiv1;
30
31
32 static void
__gxx_exception_cleanup(_Unwind_Reason_Code code,_Unwind_Exception * exc)33 __gxx_exception_cleanup (_Unwind_Reason_Code code, _Unwind_Exception *exc)
34 {
35 // This cleanup is set only for primaries.
36 __cxa_refcounted_exception *header
37 = __get_refcounted_exception_header_from_ue (exc);
38
39 // We only want to be called through _Unwind_DeleteException.
40 // _Unwind_DeleteException in the HP-UX IA64 libunwind library
41 // returns _URC_NO_REASON and not _URC_FOREIGN_EXCEPTION_CAUGHT
42 // like the GCC _Unwind_DeleteException function does.
43 if (code != _URC_FOREIGN_EXCEPTION_CAUGHT && code != _URC_NO_REASON)
44 __terminate (header->exc.terminateHandler);
45
46 if (__gnu_cxx::__eh_atomic_dec (&header->referenceCount))
47 {
48 if (header->exc.exceptionDestructor)
49 header->exc.exceptionDestructor (header + 1);
50
51 __cxa_free_exception (header + 1);
52 }
53 }
54
55 extern "C" __cxa_refcounted_exception*
56 __cxxabiv1::
__cxa_init_primary_exception(void * obj,std::type_info * tinfo,void (_GLIBCXX_CDTOR_CALLABI * dest)(void *))57 __cxa_init_primary_exception(void *obj, std::type_info *tinfo,
58 void (_GLIBCXX_CDTOR_CALLABI *dest) (void *))
59 _GLIBCXX_NOTHROW
60 {
61 __cxa_refcounted_exception *header
62 = __get_refcounted_exception_header_from_obj (obj);
63 header->referenceCount = 0;
64 header->exc.exceptionType = tinfo;
65 header->exc.exceptionDestructor = dest;
66 header->exc.unexpectedHandler = std::get_unexpected ();
67 header->exc.terminateHandler = std::get_terminate ();
68 __GXX_INIT_PRIMARY_EXCEPTION_CLASS(header->exc.unwindHeader.exception_class);
69 header->exc.unwindHeader.exception_cleanup = __gxx_exception_cleanup;
70
71 return header;
72 }
73
74 extern "C" void
__cxa_throw(void * obj,std::type_info * tinfo,void (_GLIBCXX_CDTOR_CALLABI * dest)(void *))75 __cxxabiv1::__cxa_throw (void *obj, std::type_info *tinfo,
76 void (_GLIBCXX_CDTOR_CALLABI *dest) (void *))
77 {
78 PROBE2 (throw, obj, tinfo);
79
80 __cxa_eh_globals *globals = __cxa_get_globals ();
81 globals->uncaughtExceptions += 1;
82 // Definitely a primary.
83 __cxa_refcounted_exception *header =
84 __cxa_init_primary_exception(obj, tinfo, dest);
85 header->referenceCount = 1;
86
87 #ifdef __USING_SJLJ_EXCEPTIONS__
88 _Unwind_SjLj_RaiseException (&header->exc.unwindHeader);
89 #else
90 _Unwind_RaiseException (&header->exc.unwindHeader);
91 #endif
92
93 // Some sort of unwinding error. Note that terminate is a handler.
94 __cxa_begin_catch (&header->exc.unwindHeader);
95 std::terminate ();
96 }
97
98 extern "C" void
__cxa_rethrow()99 __cxxabiv1::__cxa_rethrow ()
100 {
101 __cxa_eh_globals *globals = __cxa_get_globals ();
102 __cxa_exception *header = globals->caughtExceptions;
103
104 globals->uncaughtExceptions += 1;
105
106 // Watch for luser rethrowing with no active exception.
107 if (header)
108 {
109 // Tell __cxa_end_catch this is a rethrow.
110 if (!__is_gxx_exception_class(header->unwindHeader.exception_class))
111 globals->caughtExceptions = 0;
112 else
113 {
114 header->handlerCount = -header->handlerCount;
115 // Only notify probe for C++ exceptions.
116 PROBE2 (rethrow, __get_object_from_ambiguous_exception(header),
117 header->exceptionType);
118 }
119
120 #ifdef __USING_SJLJ_EXCEPTIONS__
121 _Unwind_SjLj_Resume_or_Rethrow (&header->unwindHeader);
122 #else
123 #if defined(_LIBUNWIND_STD_ABI)
124 _Unwind_RaiseException (&header->unwindHeader);
125 #else
126 _Unwind_Resume_or_Rethrow (&header->unwindHeader);
127 #endif
128 #endif
129
130 // Some sort of unwinding error. Note that terminate is a handler.
131 __cxa_begin_catch (&header->unwindHeader);
132 }
133 std::terminate ();
134 }
135