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
29using namespace __cxxabiv1;
30
31
32static 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
55extern "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
77extern "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
101extern "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