1// RTTI support internals for -*- C++ -*-
2// Copyright (C) 1994-2016 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