aboutsummaryrefslogtreecommitdiffstats
path: root/gcc-4.6/libstdc++-v3/libsupc++/eh_arm.cc
blob: 0112d61970e4e277636f07fbb417166e0ab79ede (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
// -*- C++ -*- ARM specific Exception handling support routines.
// Copyright (C) 2004, 2005, 2008, 2009, 2010 Free Software Foundation, Inc.
//
// This file is part of GCC.
//
// GCC is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 3, or (at your option)
// any later version.
//
// GCC is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.
//
// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
// <http://www.gnu.org/licenses/>.

#include <cxxabi.h>
#include "unwind-cxx.h"

#ifdef __ARM_EABI_UNWINDER__

using namespace __cxxabiv1;

// The GCC command-line option "-fvisibility=hidden" apparently fails to hide
// the visibility of the inline assembly function "__cxa_end_cleanup".
// We need to keep the visibility of the __cxa_* functions coherent otherwise
// linking eh_arm.o to resolve __cxa_end_cleanup (eg needed by -frtti
// -fexceptions) will disappoint the linker by exposing __cxa_type_match and
// __cxa_begin_cleanup (eg needed by __aeabi_idiv from libgcc.a).
// Therefore as a simple workaround we just force the visibility to default for
// all these __cxa functions in this module.

#pragma GCC visibility push(default)

// Given the thrown type THROW_TYPE, pointer to a variable containing a
// pointer to the exception object THROWN_PTR_P and a type CATCH_TYPE to
// compare against, return whether or not there is a match and if so,
// update *THROWN_PTR_P.

extern "C" __cxa_type_match_result
__cxa_type_match(_Unwind_Exception* ue_header,
		 const std::type_info* catch_type,
		 bool is_reference __attribute__((__unused__)),
		 void** thrown_ptr_p)
{
  bool forced_unwind = __is_gxx_forced_unwind_class(ue_header->exception_class);
  bool foreign_exception = !forced_unwind && !__is_gxx_exception_class(ue_header->exception_class);
  bool dependent_exception =
    __is_dependent_exception(ue_header->exception_class);
  __cxa_exception* xh = __get_exception_header_from_ue(ue_header);
  __cxa_dependent_exception *dx = __get_dependent_exception_from_ue(ue_header);
  const std::type_info* throw_type;

  if (forced_unwind)
    throw_type = &typeid(abi::__forced_unwind);
  else if (foreign_exception)
    throw_type = &typeid(abi::__foreign_exception);
  else if (dependent_exception)
    throw_type = __get_exception_header_from_obj
      (dx->primaryException)->exceptionType;
  else
    throw_type = xh->exceptionType;

  void* thrown_ptr = *thrown_ptr_p;

  // Pointer types need to adjust the actual pointer, not
  // the pointer to pointer that is the exception object.
  // This also has the effect of passing pointer types
  // "by value" through the __cxa_begin_catch return value.
  if (throw_type->__is_pointer_p())
    thrown_ptr = *(void**) thrown_ptr;

  if (catch_type->__do_catch(throw_type, &thrown_ptr, 1))
    {
      *thrown_ptr_p = thrown_ptr;

      if (typeid(*catch_type) == typeid (typeid(void*)))
	{
	  const __pointer_type_info *catch_pointer_type =
	    static_cast<const __pointer_type_info *> (catch_type);
	  const __pointer_type_info *throw_pointer_type =
	    static_cast<const __pointer_type_info *> (throw_type);

	  if (typeid (*catch_pointer_type->__pointee) != typeid (void)
	      && (*catch_pointer_type->__pointee != 
		  *throw_pointer_type->__pointee))
	    return ctm_succeeded_with_ptr_to_base;
	}

      return ctm_succeeded;
    }

  return ctm_failed;
}

// ABI defined routine called at the start of a cleanup handler.
extern "C" bool
__cxa_begin_cleanup(_Unwind_Exception* ue_header)
{
  __cxa_eh_globals *globals = __cxa_get_globals();
  __cxa_exception *header = __get_exception_header_from_ue(ue_header);
  bool native = __is_gxx_exception_class(header->unwindHeader.exception_class);


  if (native)
    {
      header->propagationCount++;
      // Add it to the chain if this is the first time we've seen this
      // exception.
      if (header->propagationCount == 1)
	{
	  header->nextPropagatingException = globals->propagatingExceptions;
	  globals->propagatingExceptions = header;
	}
    }
  else
    {
      // Remember the exception object, so end_cleanup can return it.
      // These cannot be stacked, so we must abort if we already have
      // a propagating exception.
      if (globals->propagatingExceptions)
	std::terminate ();
      globals->propagatingExceptions = header;
    }

  return true;
}

// Do the work for __cxa_end_cleanup.  Returns the currently propagating
// exception object.
extern "C" _Unwind_Exception *
__gnu_end_cleanup(void)
{
  __cxa_exception *header;
  __cxa_eh_globals *globals = __cxa_get_globals();

  header = globals->propagatingExceptions;

  // Check something hasn't gone horribly wrong.
  if (!header)
    std::terminate();

  if (__is_gxx_exception_class(header->unwindHeader.exception_class))
    {
      header->propagationCount--;
      if (header->propagationCount == 0)
	{
	  // Remove exception from chain.
	  globals->propagatingExceptions = header->nextPropagatingException;
	  header->nextPropagatingException = NULL;
	}
    }
  else
    globals->propagatingExceptions = NULL;

  return &header->unwindHeader;
}

// Assembly wrapper to call __gnu_end_cleanup without clobbering r1-r3.
// Also push r4 to preserve stack alignment.
#ifdef __thumb__
asm ("  .pushsection .text.__cxa_end_cleanup\n"
"	.global __cxa_end_cleanup\n"
"	.type __cxa_end_cleanup, \"function\"\n"
"	.thumb_func\n"
"__cxa_end_cleanup:\n"
"	push\t{r1, r2, r3, r4}\n"
"	bl\t__gnu_end_cleanup\n"
"	pop\t{r1, r2, r3, r4}\n"
"	bl\t_Unwind_Resume @ Never returns\n"
"	.popsection\n");
#else
asm ("  .pushsection .text.__cxa_end_cleanup\n"
"	.global __cxa_end_cleanup\n"
"	.type __cxa_end_cleanup, \"function\"\n"
"__cxa_end_cleanup:\n"
"	stmfd\tsp!, {r1, r2, r3, r4}\n"
"	bl\t__gnu_end_cleanup\n"
"	ldmfd\tsp!, {r1, r2, r3, r4}\n"
"	bl\t_Unwind_Resume @ Never returns\n"
"	.popsection\n");
#endif

#pragma GCC visibility pop

#endif