1// -*- C++ -*- Helpers for calling unextected and terminate
2// Copyright (C) 2001-2020 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 <cstdlib>
27#include <bits/exception_defines.h>
28#include "unwind-cxx.h"
29
30using namespace __cxxabiv1;
31
32#include "unwind-pe.h"
33
34
35// Helper routine for when the exception handling code needs to call
36// terminate.
37
38extern "C" void
39__cxa_call_terminate(_Unwind_Exception* ue_header) throw ()
40{
41
42  if (ue_header)
43    {
44      // terminate is classed as a catch handler.
45      __cxa_begin_catch(ue_header);
46
47      // Call the terminate handler that was in effect when we threw this
48      // exception.  */
49      if (__is_gxx_exception_class(ue_header->exception_class))
50	{
51	  __cxa_exception* xh;
52
53	  xh = __get_exception_header_from_ue(ue_header);
54	  __terminate(xh->terminateHandler);
55	}
56    }
57  /* Call the global routine if we don't have anything better.  */
58  std::terminate();
59}
60
61
62#ifdef __ARM_EABI_UNWINDER__
63// The ARM EABI __cxa_call_unexpected has the same semantics as the generic
64// routine, but the exception specification has a different format.
65extern "C" void
66__cxa_call_unexpected(void* exc_obj_in)
67{
68  _Unwind_Exception* exc_obj
69    = reinterpret_cast<_Unwind_Exception*>(exc_obj_in);
70
71  int rtti_count = 0;
72  _Unwind_Word rtti_stride = 0;
73  _Unwind_Word* rtti_list = NULL;
74  _Unwind_Ptr rtti_base = 0;
75  bool foreign_exception;
76  std::unexpected_handler unexpectedHandler = NULL;
77  std::terminate_handler terminateHandler = NULL;
78  __cxa_exception* xh;
79  if (__is_gxx_exception_class(exc_obj->exception_class))
80    {
81      // Save data from the EO, which may be clobbered by _cxa_begin_catch.
82      xh = __get_exception_header_from_ue(exc_obj);
83      unexpectedHandler = xh->unexpectedHandler;
84      terminateHandler = xh->terminateHandler;
85      rtti_count = exc_obj->barrier_cache.bitpattern[1];
86      rtti_base = (_Unwind_Ptr) exc_obj->barrier_cache.bitpattern[2];
87      rtti_stride = exc_obj->barrier_cache.bitpattern[3];
88      rtti_list = (_Unwind_Word*) exc_obj->barrier_cache.bitpattern[4];
89      foreign_exception = false;
90    }
91  else
92    foreign_exception = true;
93
94  /* This must be called after extracting data from the EO, but before
95     calling unexpected().   */
96  __cxa_begin_catch(exc_obj);
97
98  // This function is a handler for our exception argument.  If we exit
99  // by throwing a different exception, we'll need the original cleaned up.
100  struct end_catch_protect
101  {
102    end_catch_protect() { }
103    ~end_catch_protect() { __cxa_end_catch(); }
104  } end_catch_protect_obj;
105
106
107  __try
108    {
109      if (foreign_exception)
110	std::unexpected();
111      else
112	__unexpected(unexpectedHandler);
113    }
114  __catch(...)
115    {
116      /* See if the new exception matches the rtti list.  */
117      if (foreign_exception)
118	std::terminate();
119
120      // Get the exception thrown from unexpected.
121
122      __cxa_eh_globals* globals = __cxa_get_globals_fast();
123      __cxa_exception* new_xh = globals->caughtExceptions;
124      void* new_ptr = __get_object_from_ambiguous_exception (new_xh);
125      const std::type_info* catch_type;
126      int n;
127      bool bad_exception_allowed = false;
128      const std::type_info& bad_exc = typeid(std::bad_exception);
129
130      // Check the new exception against the rtti list
131      for (n = 0; n < rtti_count; n++)
132	{
133	  _Unwind_Word offset;
134
135	  offset = (_Unwind_Word) &rtti_list[n * (rtti_stride >> 2)];
136	  offset = _Unwind_decode_typeinfo_ptr(rtti_base, offset);
137	  catch_type = (const std::type_info*) (offset);
138
139	  if (__cxa_type_match(&new_xh->unwindHeader, catch_type, false,
140			       &new_ptr) != ctm_failed)
141	    __throw_exception_again;
142
143	  // If the exception spec allows std::bad_exception, throw that.
144	  // We don't have a thrown object to compare against, but since
145	  // bad_exception doesn't have virtual bases, that's OK; just pass NULL.
146	  void* obj = NULL;
147	  if (catch_type->__do_catch(&bad_exc, &obj, 1))
148	    bad_exception_allowed = true;
149	}
150
151      // If the exception spec allows std::bad_exception, throw that.
152#if __cpp_exceptions
153      if (bad_exception_allowed)
154	throw std::bad_exception();
155#endif
156
157      // Otherwise, die.
158      __terminate(terminateHandler);
159    }
160}
161#endif // __ARM_EABI_UNWINDER__
162