1 // -*- C++ -*- Exception handling routines for throwing. 2 // Copyright (C) 2001-2022 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 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:: 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 #pragma GCC diagnostic push 67 #pragma GCC diagnostic ignored "-Wdeprecated-declarations" 68 header->exc.unexpectedHandler = std::get_unexpected (); 69 #pragma GCC diagnostic pop 70 header->exc.terminateHandler = std::get_terminate (); 71 __GXX_INIT_PRIMARY_EXCEPTION_CLASS(header->exc.unwindHeader.exception_class); 72 header->exc.unwindHeader.exception_cleanup = __gxx_exception_cleanup; 73 74 return header; 75 } 76 77 extern "C" void 78 __cxxabiv1::__cxa_throw (void *obj, std::type_info *tinfo, 79 void (_GLIBCXX_CDTOR_CALLABI *dest) (void *)) 80 { 81 PROBE2 (throw, obj, tinfo); 82 83 __cxa_eh_globals *globals = __cxa_get_globals (); 84 globals->uncaughtExceptions += 1; 85 // Definitely a primary. 86 __cxa_refcounted_exception *header = 87 __cxa_init_primary_exception(obj, tinfo, dest); 88 header->referenceCount = 1; 89 90 #ifdef __USING_SJLJ_EXCEPTIONS__ 91 _Unwind_SjLj_RaiseException (&header->exc.unwindHeader); 92 #else 93 _Unwind_RaiseException (&header->exc.unwindHeader); 94 #endif 95 96 // Some sort of unwinding error. Note that terminate is a handler. 97 __cxa_begin_catch (&header->exc.unwindHeader); 98 std::terminate (); 99 } 100 101 extern "C" void 102 __cxxabiv1::__cxa_rethrow () 103 { 104 __cxa_eh_globals *globals = __cxa_get_globals (); 105 __cxa_exception *header = globals->caughtExceptions; 106 107 globals->uncaughtExceptions += 1; 108 109 // Watch for luser rethrowing with no active exception. 110 if (header) 111 { 112 // Tell __cxa_end_catch this is a rethrow. 113 if (!__is_gxx_exception_class(header->unwindHeader.exception_class)) 114 globals->caughtExceptions = 0; 115 else 116 { 117 header->handlerCount = -header->handlerCount; 118 // Only notify probe for C++ exceptions. 119 PROBE2 (rethrow, __get_object_from_ambiguous_exception(header), 120 header->exceptionType); 121 } 122 123 #ifdef __USING_SJLJ_EXCEPTIONS__ 124 _Unwind_SjLj_Resume_or_Rethrow (&header->unwindHeader); 125 #else 126 #if defined(_LIBUNWIND_STD_ABI) 127 _Unwind_RaiseException (&header->unwindHeader); 128 #else 129 _Unwind_Resume_or_Rethrow (&header->unwindHeader); 130 #endif 131 #endif 132 133 // Some sort of unwinding error. Note that terminate is a handler. 134 __cxa_begin_catch (&header->unwindHeader); 135 } 136 std::terminate (); 137 } 138