1 // -*- C++ -*- Exception handling routines for Transactional Memory. 2 // Copyright (C) 2009, 2011, 2012 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 <cstdlib> 26 #include "unwind-cxx.h" 27 28 using namespace __cxxabiv1; 29 30 // Free one C++ exception. 31 32 static void 33 free_any_cxa_exception (_Unwind_Exception *eo) 34 { 35 __cxa_refcounted_exception *h 36 = __get_refcounted_exception_header_from_ue (eo); 37 38 if (__is_dependent_exception (eo->exception_class)) 39 { 40 __cxa_dependent_exception *dep 41 = __get_dependent_exception_from_ue (eo); 42 43 h = __get_refcounted_exception_header_from_obj (dep->primaryException); 44 45 __cxa_free_dependent_exception (dep); 46 } 47 48 #if __GCC_ATOMIC_INT_LOCK_FREE > 1 49 if (__atomic_sub_fetch (&h->referenceCount, 1, __ATOMIC_ACQ_REL) == 0) 50 #endif 51 __cxa_free_exception (h + 1); 52 } 53 54 // Cleanup exception handling state while rolling back state for 55 // a software transactional memory transaction. 56 // 57 // UNTHROWN_OBJ is non-null if we've called __cxa_allocate_exception 58 // but not yet called __cxa_throw for it. 59 // 60 // CLEANUP_EXC is non-null if we're currently processing a cleanup 61 // along an exception path, but we've not caught the exception yet. 62 // 63 // CAUGHT_COUNT is the nesting depth of __cxa_begin_catch within 64 // the transaction; undo as if calling __cxa_end_catch that many times. 65 66 extern "C" void 67 __cxxabiv1::__cxa_tm_cleanup (void *unthrown_obj, 68 void *cleanup_exc, 69 unsigned int caught_count) throw() 70 { 71 __cxa_eh_globals *globals = __cxa_get_globals_fast (); 72 73 // Handle a C++ exception not yet thrown. 74 if (unthrown_obj) 75 { 76 globals->uncaughtExceptions -= 1; 77 __cxa_free_exception (unthrown_obj); 78 } 79 80 // Handle an exception not yet caught ie. processing a cleanup 81 // in between the throw and the catch. 82 if (cleanup_exc) 83 { 84 _Unwind_Exception *eo 85 = reinterpret_cast <_Unwind_Exception *>(cleanup_exc); 86 if (__is_gxx_exception_class (eo->exception_class)) 87 free_any_cxa_exception (eo); 88 else 89 _Unwind_DeleteException (eo); 90 } 91 92 // Do __cxa_end_catch caught_count times, but don't bother running 93 // the destructors for the objects involved. All of that is being 94 // undone by the transaction restart. 95 if (caught_count > 0) 96 { 97 __cxa_exception *h = globals->caughtExceptions; 98 99 // Rethrown foreign exceptions are removed from the stack immediately. 100 // We would have freed this exception via THIS_EXC above. 101 if (h == NULL) 102 return; 103 104 do 105 { 106 __cxa_exception *next; 107 _Unwind_Exception *eo = &h->unwindHeader; 108 109 if (__is_gxx_exception_class (eo->exception_class)) 110 { 111 next = h->nextException; 112 free_any_cxa_exception (eo); 113 } 114 else 115 { 116 _Unwind_DeleteException (eo); 117 next = 0; 118 } 119 120 h = next; 121 } 122 while (--caught_count); 123 124 globals->caughtExceptions = h; 125 } 126 } 127