1// -*- C++ -*- ARM specific Exception handling support routines.
2// Copyright (C) 2004, 2005 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 2, 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// You should have received a copy of the GNU General Public License
17// along with GCC; see the file COPYING.  If not, write to
18// the Free Software Foundation, 51 Franklin Street, Fifth Floor,
19// Boston, MA 02110-1301, USA.
20
21// As a special exception, you may use this file as part of a free software
22// library without restriction.  Specifically, if other files instantiate
23// templates or use macros or inline functions from this file, or you compile
24// this file and link it with other files to produce an executable, this
25// file does not by itself cause the resulting executable to be covered by
26// the GNU General Public License.  This exception does not however
27// invalidate any other reasons why the executable file might be covered by
28// the GNU General Public License.
29
30#include <cxxabi.h>
31#include "unwind-cxx.h"
32
33#ifdef __ARM_EABI_UNWINDER__
34
35using namespace __cxxabiv1;
36
37
38// Given the thrown type THROW_TYPE, pointer to a variable containing a
39// pointer to the exception object THROWN_PTR_P and a type CATCH_TYPE to
40// compare against, return whether or not there is a match and if so,
41// update *THROWN_PTR_P.
42
43extern "C" __cxa_type_match_result
44__cxa_type_match(_Unwind_Exception* ue_header,
45		 const std::type_info* catch_type,
46		 bool is_reference __attribute__((__unused__)),
47		 void** thrown_ptr_p)
48{
49  if (!__is_gxx_exception_class(ue_header->exception_class))
50    return ctm_failed;
51
52  __cxa_exception* xh = __get_exception_header_from_ue(ue_header);
53  const std::type_info* throw_type = xh->exceptionType;
54  void* thrown_ptr = *thrown_ptr_p;
55
56  // Pointer types need to adjust the actual pointer, not
57  // the pointer to pointer that is the exception object.
58  // This also has the effect of passing pointer types
59  // "by value" through the __cxa_begin_catch return value.
60  if (throw_type->__is_pointer_p())
61    thrown_ptr = *(void**) thrown_ptr;
62
63  if (catch_type->__do_catch(throw_type, &thrown_ptr, 1))
64    {
65      *thrown_ptr_p = thrown_ptr;
66
67      if (typeid(*catch_type) == typeid (typeid(void*)))
68	{
69	  const __pointer_type_info *catch_pointer_type =
70	    static_cast<const __pointer_type_info *> (catch_type);
71	  const __pointer_type_info *throw_pointer_type =
72	    static_cast<const __pointer_type_info *> (throw_type);
73
74	  if (typeid (*catch_pointer_type->__pointee) != typeid (void)
75	      && (*catch_pointer_type->__pointee !=
76		  *throw_pointer_type->__pointee))
77	    return ctm_succeeded_with_ptr_to_base;
78	}
79
80      return ctm_succeeded;
81    }
82
83  return ctm_failed;
84}
85
86// ABI defined routine called at the start of a cleanup handler.
87extern "C" bool
88__cxa_begin_cleanup(_Unwind_Exception* ue_header)
89{
90  __cxa_eh_globals *globals = __cxa_get_globals();
91  __cxa_exception *header = __get_exception_header_from_ue(ue_header);
92  bool native = __is_gxx_exception_class(header->unwindHeader.exception_class);
93
94
95  if (native)
96    {
97      header->propagationCount++;
98      // Add it to the chain if this is the first time we've seen this
99      // exception.
100      if (header->propagationCount == 1)
101	{
102	  header->nextPropagatingException = globals->propagatingExceptions;
103	  globals->propagatingExceptions = header;
104	}
105    }
106  else
107    {
108      // Remember the exception object, so end_cleanup can return it.
109      // These cannot be stacked, so we must abort if we already have
110      // a propagating exception.
111      if (globals->propagatingExceptions)
112	std::terminate ();
113      globals->propagatingExceptions = header;
114    }
115
116  return true;
117}
118
119// Do the work for __cxa_end_cleanup.  Returns the currently propagating
120// exception object.
121extern "C" _Unwind_Exception *
122__gnu_end_cleanup(void)
123{
124  __cxa_exception *header;
125  __cxa_eh_globals *globals = __cxa_get_globals();
126
127  header = globals->propagatingExceptions;
128
129  // Check something hasn't gone horribly wrong.
130  if (!header)
131    std::terminate();
132
133  if (__is_gxx_exception_class(header->unwindHeader.exception_class))
134    {
135      header->propagationCount--;
136      if (header->propagationCount == 0)
137	{
138	  // Remove exception from chain.
139	  globals->propagatingExceptions = header->nextPropagatingException;
140	  header->nextPropagatingException = NULL;
141	}
142    }
143  else
144    globals->propagatingExceptions = NULL;
145
146  return &header->unwindHeader;
147}
148
149// Assembly wrapper to call __gnu_end_cleanup without clobbering r1-r3.
150// Also push r4 to preserve stack alignment.
151#ifdef __thumb__
152asm (".global __cxa_end_cleanup\n"
153"	.type __cxa_end_cleanup, \"function\"\n"
154"	.thumb_func\n"
155"__cxa_end_cleanup:\n"
156"	push\t{r1, r2, r3, r4}\n"
157"	bl\t__gnu_end_cleanup\n"
158"	pop\t{r1, r2, r3, r4}\n"
159"	bl\t_Unwind_Resume @ Never returns\n");
160#else
161asm (".global __cxa_end_cleanup\n"
162"	.type __cxa_end_cleanup, \"function\"\n"
163"__cxa_end_cleanup:\n"
164"	stmfd\tsp!, {r1, r2, r3, r4}\n"
165"	bl\t__gnu_end_cleanup\n"
166"	ldmfd\tsp!, {r1, r2, r3, r4}\n"
167"	bl\t_Unwind_Resume @ Never returns\n");
168#endif
169
170#endif
171