1// RTTI support internals for -*- C++ -*-
2// Copyright (C) 1994-2015 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 "typeinfo"
26#include <cstddef>
27
28// Class declarations shared between the typeinfo implementation files.
29
30#include <cxxabi.h>
31
32namespace __cxxabiv1 {
33
34namespace {
35
36using namespace std;
37using namespace abi;
38
39// Initial part of a vtable, this structure is used with offsetof, so we don't
40// have to keep alignments consistent manually.
41struct vtable_prefix
42{
43  // Offset to most derived object.
44  ptrdiff_t whole_object;
45
46  // Additional padding if necessary.
47#ifdef _GLIBCXX_VTABLE_PADDING
48  ptrdiff_t padding1;
49#endif
50
51  // Pointer to most derived type_info.
52  const __class_type_info *whole_type;
53
54  // Additional padding if necessary.
55#ifdef _GLIBCXX_VTABLE_PADDING
56  ptrdiff_t padding2;
57#endif
58
59  // What a class's vptr points to.
60  const void *origin;
61};
62
63template <typename T>
64inline const T *
65adjust_pointer (const void *base, ptrdiff_t offset)
66{
67  return reinterpret_cast <const T *>
68    (reinterpret_cast <const char *> (base) + offset);
69}
70
71// ADDR is a pointer to an object.  Convert it to a pointer to a base,
72// using OFFSET. IS_VIRTUAL is true, if we are getting a virtual base.
73inline void const *
74convert_to_base (void const *addr, bool is_virtual, ptrdiff_t offset)
75{
76  if (is_virtual)
77    {
78      const void *vtable = *static_cast <const void *const *> (addr);
79
80      offset = *adjust_pointer<ptrdiff_t> (vtable, offset);
81    }
82
83  return adjust_pointer<void> (addr, offset);
84}
85
86// some predicate functions for __class_type_info::__sub_kind
87inline bool contained_p (__class_type_info::__sub_kind access_path)
88{
89  return access_path >= __class_type_info::__contained_mask;
90}
91inline bool public_p (__class_type_info::__sub_kind access_path)
92{
93  return access_path & __class_type_info::__contained_public_mask;
94}
95inline bool virtual_p (__class_type_info::__sub_kind access_path)
96{
97  return (access_path & __class_type_info::__contained_virtual_mask);
98}
99inline bool contained_public_p (__class_type_info::__sub_kind access_path)
100{
101  return ((access_path & __class_type_info::__contained_public)
102          == __class_type_info::__contained_public);
103}
104inline bool contained_nonpublic_p (__class_type_info::__sub_kind access_path)
105{
106  return ((access_path & __class_type_info::__contained_public)
107          == __class_type_info::__contained_mask);
108}
109inline bool contained_nonvirtual_p (__class_type_info::__sub_kind access_path)
110{
111  return ((access_path & (__class_type_info::__contained_mask
112                          | __class_type_info::__contained_virtual_mask))
113          == __class_type_info::__contained_mask);
114}
115
116static const __class_type_info *const nonvirtual_base_type =
117    static_cast <const __class_type_info *> (0) + 1;
118
119} // namespace
120
121// __upcast_result is used to hold information during traversal of a class
122// hierarchy when catch matching.
123struct __class_type_info::__upcast_result
124{
125  const void *dst_ptr;        // pointer to caught object
126  __sub_kind part2dst;        // path from current base to target
127  int src_details;            // hints about the source type hierarchy
128  const __class_type_info *base_type; // where we found the target,
129                              // if in vbase the __class_type_info of vbase
130                              // if a non-virtual base then 1
131                              // else NULL
132  __upcast_result (int d)
133    :dst_ptr (NULL), part2dst (__unknown), src_details (d), base_type (NULL)
134    {}
135};
136
137// __dyncast_result is used to hold information during traversal of a class
138// hierarchy when dynamic casting.
139struct __class_type_info::__dyncast_result
140{
141  const void *dst_ptr;        // pointer to target object or NULL
142  __sub_kind whole2dst;       // path from most derived object to target
143  __sub_kind whole2src;       // path from most derived object to sub object
144  __sub_kind dst2src;         // path from target to sub object
145  int whole_details;          // details of the whole class hierarchy
146
147  __dyncast_result (int details_ = __vmi_class_type_info::__flags_unknown_mask)
148    :dst_ptr (NULL), whole2dst (__unknown),
149     whole2src (__unknown), dst2src (__unknown),
150     whole_details (details_)
151    {}
152
153protected:
154  __dyncast_result(const __dyncast_result&);
155
156  __dyncast_result&
157  operator=(const __dyncast_result&);
158};
159
160inline __class_type_info::__sub_kind __class_type_info::
161__find_public_src (ptrdiff_t src2dst,
162                   const void *obj_ptr,
163                   const __class_type_info *src_type,
164                   const void *src_ptr) const
165{
166  if (src2dst >= 0)
167    return adjust_pointer <void> (obj_ptr, src2dst) == src_ptr
168            ? __contained_public : __not_contained;
169  if (src2dst == -2)
170    return __not_contained;
171  return __do_find_public_src (src2dst, obj_ptr, src_type, src_ptr);
172}
173
174}
175