1// -*- C++ -*- Exception handling routines for Transactional Memory. 2// Copyright (C) 2009-2015 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 28using namespace __cxxabiv1; 29 30// Free one C++ exception. 31 32static void 33free_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 66extern "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