typeinfo revision 169691 
1// RTTI support for -*- C++ -*-
2// Copyright (C) 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002,
3// 2003, 2004, 2005, 2006, 2007
4// Free Software Foundation
5//
6// This file is part of GCC.
7//
8// GCC is free software; you can redistribute it and/or modify
9// it under the terms of the GNU General Public License as published by
10// the Free Software Foundation; either version 2, or (at your option)
11// any later version.
12// 
13// GCC is distributed in the hope that it will be useful,
14// but WITHOUT ANY WARRANTY; without even the implied warranty of
15// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16// GNU General Public License for more details.
17// 
18// You should have received a copy of the GNU General Public License
19// along with GCC; see the file COPYING.  If not, write to
20// the Free Software Foundation, 51 Franklin Street, Fifth Floor,
21// Boston, MA 02110-1301, USA.
22
23// As a special exception, you may use this file as part of a free software
24// library without restriction.  Specifically, if other files instantiate
25// templates or use macros or inline functions from this file, or you compile
26// this file and link it with other files to produce an executable, this
27// file does not by itself cause the resulting executable to be covered by
28// the GNU General Public License.  This exception does not however
29// invalidate any other reasons why the executable file might be covered by
30// the GNU General Public License.
31
32/** @file typeinfo
33 *  This is a Standard C++ Library header.
34 */
35
36#ifndef _TYPEINFO
37#define _TYPEINFO
38
39#include <exception>
40
41#pragma GCC visibility push(default)
42
43extern "C++" {
44
45namespace __cxxabiv1
46{
47  class __class_type_info;
48} // namespace __cxxabiv1
49
50#ifndef __GXX_MERGED_TYPEINFO_NAMES
51  #if !__GXX_WEAK__
52    // If weak symbols are not supported, typeinfo names are not merged.
53    #define __GXX_MERGED_TYPEINFO_NAMES 0
54  #else
55    // On platforms that support weak symbols, typeinfo names are merged.
56    #define __GXX_MERGED_TYPEINFO_NAMES 1
57  #endif
58#endif
59
60namespace std 
61{
62  /**
63   *  @brief  Part of RTTI.
64   *
65   *  The @c type_info class describes type information generated by
66   *  an implementation.
67  */
68  class type_info 
69  {
70  public:
71    /** Destructor. Being the first non-inline virtual function, this
72     *  controls in which translation unit the vtable is emitted. The
73     *  compiler makes use of that information to know where to emit
74     *  the runtime-mandated type_info structures in the new-abi.  */
75    virtual ~type_info();
76
77  private:
78    /// Assigning type_info is not supported.  Made private.
79    type_info& operator=(const type_info&);
80    type_info(const type_info&);
81    
82  protected:
83    const char *__name;
84    
85  protected:
86    explicit type_info(const char *__n): __name(__n) { }
87    
88  public:
89    // the public interface
90    /** Returns an @e implementation-defined byte string; this is not
91     *  portable between compilers!  */
92    const char* name() const
93    { return __name; }
94
95#if !__GXX_MERGED_TYPEINFO_NAMES
96    bool before(const type_info& __arg) const;
97    // In old abi, or when weak symbols are not supported, there can
98    // be multiple instances of a type_info object for one
99    // type. Uniqueness must use the _name value, not object address.
100    bool operator==(const type_info& __arg) const;
101#else
102    /** Returns true if @c *this precedes @c __arg in the implementation's
103     *  collation order.  */
104    // In new abi we can rely on type_info's NTBS being unique,
105    // and therefore address comparisons are sufficient.
106    bool before(const type_info& __arg) const
107    { return __name < __arg.__name; }
108    bool operator==(const type_info& __arg) const
109    { return __name == __arg.__name; }
110#endif
111    bool operator!=(const type_info& __arg) const
112    { return !operator==(__arg); }
113    
114    // the internal interface
115  public:
116    // return true if this is a pointer type of some kind
117    virtual bool __is_pointer_p() const;
118    // return true if this is a function type
119    virtual bool __is_function_p() const;
120
121    // Try and catch a thrown type. Store an adjusted pointer to the
122    // caught type in THR_OBJ. If THR_TYPE is not a pointer type, then
123    // THR_OBJ points to the thrown object. If THR_TYPE is a pointer
124    // type, then THR_OBJ is the pointer itself. OUTER indicates the
125    // number of outer pointers, and whether they were const
126    // qualified.
127    virtual bool __do_catch(const type_info *__thr_type, void **__thr_obj,
128			    unsigned __outer) const;
129
130    // internally used during catch matching
131    virtual bool __do_upcast(const __cxxabiv1::__class_type_info *__target,
132			     void **__obj_ptr) const;
133  };
134
135  /**
136   *  @brief  Thrown during incorrect typecasting.
137   *
138   *  If you attempt an invalid @c dynamic_cast expression, an instance of
139   *  this class (or something derived from this class) is thrown.  */
140  class bad_cast : public exception 
141  {
142  public:
143    bad_cast() throw() { }
144    // This declaration is not useless:
145    // http://gcc.gnu.org/onlinedocs/gcc-3.0.2/gcc_6.html#SEC118
146    virtual ~bad_cast() throw();
147    // See comment in eh_exception.cc.
148    virtual const char* what() const throw();
149  };
150  
151  /** If you use a NULL pointer in a @c typeid expression, this is thrown.  */
152  class bad_typeid : public exception 
153  {
154  public:
155    bad_typeid () throw() { }
156    // This declaration is not useless:
157    // http://gcc.gnu.org/onlinedocs/gcc-3.0.2/gcc_6.html#SEC118
158    virtual ~bad_typeid() throw();
159    // See comment in eh_exception.cc.
160    virtual const char* what() const throw();
161  };
162} // namespace std
163
164#pragma GCC visibility pop
165
166} // extern "C++"
167#endif
168