unwind-cxx.h revision 97403 
1// -*- C++ -*- Exception handling and frame unwind runtime interface routines.
2// Copyright (C) 2001 Free Software Foundation, Inc.
3//
4// This file is part of GNU CC.
5//
6// GNU CC 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// GNU CC 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 GNU CC; see the file COPYING.  If not, write to
18// the Free Software Foundation, 59 Temple Place - Suite 330,
19// Boston, MA 02111-1307, 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// This is derived from the C++ ABI for IA-64.  Where we diverge
31// for cross-architecture compatibility are noted with "@@@".
32
33#ifndef __UNWIND_CXX_H
34#define __UNWIND_CXX_H 1
35
36// Level 2: C++ ABI
37
38#include <typeinfo>
39#include <exception>
40#include <cstddef>
41#include "unwind.h"
42
43namespace __cxxabiv1
44{
45
46// A C++ exception object consists of a header, which is a wrapper around
47// an unwind object header with additional C++ specific information,
48// followed by the exception object itself.
49
50struct __cxa_exception
51{
52  // Manage the exception object itself.
53  std::type_info *exceptionType;
54  void (*exceptionDestructor)(void *);
55
56  // The C++ standard has entertaining rules wrt calling set_terminate
57  // and set_unexpected in the middle of the exception cleanup process.
58  std::unexpected_handler unexpectedHandler;
59  std::terminate_handler terminateHandler;
60
61  // The caught exception stack threads through here.
62  __cxa_exception *nextException;
63
64  // How many nested handlers have caught this exception.  A negated
65  // value is a signal that this object has been rethrown.
66  int handlerCount;
67
68  // Cache parsed handler data from the personality routine Phase 1
69  // for Phase 2 and __cxa_call_unexpected.
70  int handlerSwitchValue;
71  const unsigned char *actionRecord;
72  const unsigned char *languageSpecificData;
73  void *catchTemp;
74  void *adjustedPtr;
75
76  // The generic exception header.  Must be last.
77  _Unwind_Exception unwindHeader;
78};
79
80// Each thread in a C++ program has access to a __cxa_eh_globals object.
81struct __cxa_eh_globals
82{
83  __cxa_exception *caughtExceptions;
84  unsigned int uncaughtExceptions;
85};
86
87
88// The __cxa_eh_globals for the current thread can be obtained by using
89// either of the following functions.  The "fast" version assumes at least
90// one prior call of __cxa_get_globals has been made from the current
91// thread, so no initialization is necessary.
92extern "C" __cxa_eh_globals *__cxa_get_globals () throw();
93extern "C" __cxa_eh_globals *__cxa_get_globals_fast () throw();
94
95// Allocate memory for the exception plus the thown object.
96extern "C" void *__cxa_allocate_exception(std::size_t thrown_size) throw();
97
98// Free the space allocated for the exception.
99extern "C" void __cxa_free_exception(void *thrown_exception) throw();
100
101// Throw the exception.
102extern "C" void __cxa_throw (void *thrown_exception,
103			     std::type_info *tinfo,
104			     void (*dest) (void *))
105     __attribute__((noreturn));
106
107// Used to implement exception handlers.
108extern "C" void *__cxa_begin_catch (void *) throw();
109extern "C" void __cxa_end_catch ();
110extern "C" void __cxa_rethrow () __attribute__((noreturn));
111
112// These facilitate code generation for recurring situations.
113extern "C" void __cxa_bad_cast ();
114extern "C" void __cxa_bad_typeid ();
115
116// @@@ These are not directly specified by the IA-64 C++ ABI.
117
118// Handles re-checking the exception specification if unexpectedHandler
119// throws, and if bad_exception needs to be thrown.  Called from the
120// compiler.
121extern "C" void __cxa_call_unexpected (void *) __attribute__((noreturn));
122
123// Invokes given handler, dying appropriately if the user handler was
124// so inconsiderate as to return.
125extern void __terminate(std::terminate_handler) __attribute__((noreturn));
126extern void __unexpected(std::unexpected_handler) __attribute__((noreturn));
127
128// The current installed user handlers.
129extern std::terminate_handler __terminate_handler;
130extern std::unexpected_handler __unexpected_handler;
131
132// These are explicitly GNU C++ specific.
133
134// This is the exception class we report -- "GNUCC++\0".
135const _Unwind_Exception_Class __gxx_exception_class
136= ((((((((_Unwind_Exception_Class) 'G'
137	 << 8 | (_Unwind_Exception_Class) 'N')
138	<< 8 | (_Unwind_Exception_Class) 'U')
139       << 8 | (_Unwind_Exception_Class) 'C')
140      << 8 | (_Unwind_Exception_Class) 'C')
141     << 8 | (_Unwind_Exception_Class) '+')
142    << 8 | (_Unwind_Exception_Class) '+')
143   << 8 | (_Unwind_Exception_Class) '\0');
144
145// GNU C++ personality routine, Version 0.
146extern "C" _Unwind_Reason_Code __gxx_personality_v0
147     (int, _Unwind_Action, _Unwind_Exception_Class,
148      struct _Unwind_Exception *, struct _Unwind_Context *);
149
150// GNU C++ sjlj personality routine, Version 0.
151extern "C" _Unwind_Reason_Code __gxx_personality_sj0
152     (int, _Unwind_Action, _Unwind_Exception_Class,
153      struct _Unwind_Exception *, struct _Unwind_Context *);
154
155// Acquire the C++ exception header from the C++ object.
156static inline __cxa_exception *
157__get_exception_header_from_obj (void *ptr)
158{
159  return reinterpret_cast<__cxa_exception *>(ptr) - 1;
160}
161
162// Acquire the C++ exception header from the generic exception header.
163static inline __cxa_exception *
164__get_exception_header_from_ue (_Unwind_Exception *exc)
165{
166  return reinterpret_cast<__cxa_exception *>(exc + 1) - 1;
167}
168
169} /* namespace __cxxabiv1 */
170
171#endif // __UNWIND_CXX_H
172