1 // -*- C++ -*- Exception handling routines for Transactional Memory.
2 // Copyright (C) 2009-2016 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
free_any_cxa_exception(_Unwind_Exception * eo)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
__cxa_tm_cleanup(void * unthrown_obj,void * cleanup_exc,unsigned int caught_count)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