libstdc++-v3/libsupc++/tinfo.h

   1 // RTTI support internals for -*- C++ -*-
   2 // Copyright (C) 1994-2013 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
  32 namespace __cxxabiv1 {
  33
  34 inline bool __pbase_type_info::
  35 __pointer_catch (const __pbase_type_info *thrown_type,
  36                  void **thr_obj,
  37                  unsigned outer) const
  38 {
  39   return __pointee->__do_catch (thrown_type->__pointee, thr_obj, outer + 2);
  40 }
  41
  42 namespace {
  43
  44 using namespace std;
  45 using namespace abi;
  46
  47 // Initial part of a vtable, this structure is used with offsetof, so we don't
  48 // have to keep alignments consistent manually.
  49 struct vtable_prefix
  50 {
  51   // Offset to most derived object.
  52   ptrdiff_t whole_object;
  53
  54   // Additional padding if necessary.
  55 #ifdef _GLIBCXX_VTABLE_PADDING
  56   ptrdiff_t padding1;
  57 #endif
  58
  59   // Pointer to most derived type_info.
  60   const __class_type_info *whole_type;
  61
  62   // Additional padding if necessary.
  63 #ifdef _GLIBCXX_VTABLE_PADDING
  64   ptrdiff_t padding2;
  65 #endif
  66
  67   // What a class's vptr points to.
  68   const void *origin;
  69 };
  70
  71 template <typename T>
  72 inline const T *
  73 adjust_pointer (const void *base, ptrdiff_t offset)
  74 {
  75   return reinterpret_cast <const T *>
  76     (reinterpret_cast <const char *> (base) + offset);
  77 }
  78
  79 // ADDR is a pointer to an object.  Convert it to a pointer to a base,
  80 // using OFFSET. IS_VIRTUAL is true, if we are getting a virtual base.
  81 inline void const *
  82 convert_to_base (void const *addr, bool is_virtual, ptrdiff_t offset)
  83 {
  84   if (is_virtual)
  85     {
  86       const void *vtable = *static_cast <const void *const *> (addr);
  87
  88       offset = *adjust_pointer<ptrdiff_t> (vtable, offset);
  89     }
  90
  91   return adjust_pointer<void> (addr, offset);
  92 }
  93
  94 // some predicate functions for __class_type_info::__sub_kind
  95 inline bool contained_p (__class_type_info::__sub_kind access_path)
  96 {
  97   return access_path >= __class_type_info::__contained_mask;
  98 }
  99 inline bool public_p (__class_type_info::__sub_kind access_path)
 100 {
 101   return access_path & __class_type_info::__contained_public_mask;
 102 }
 103 inline bool virtual_p (__class_type_info::__sub_kind access_path)
 104 {
 105   return (access_path & __class_type_info::__contained_virtual_mask);
 106 }
 107 inline bool contained_public_p (__class_type_info::__sub_kind access_path)
 108 {
 109   return ((access_path & __class_type_info::__contained_public)
 110           == __class_type_info::__contained_public);
 111 }
 112 inline bool contained_nonpublic_p (__class_type_info::__sub_kind access_path)
 113 {
 114   return ((access_path & __class_type_info::__contained_public)
 115           == __class_type_info::__contained_mask);
 116 }
 117 inline bool contained_nonvirtual_p (__class_type_info::__sub_kind access_path)
 118 {
 119   return ((access_path & (__class_type_info::__contained_mask
 120                           | __class_type_info::__contained_virtual_mask))
 121           == __class_type_info::__contained_mask);
 122 }
 123
 124 static const __class_type_info *const nonvirtual_base_type =
 125     static_cast <const __class_type_info *> (0) + 1;
 126
 127 } // namespace
 128
 129 // __upcast_result is used to hold information during traversal of a class
 130 // hierarchy when catch matching.
 131 struct __class_type_info::__upcast_result
 132 {
 133   const void *dst_ptr;        // pointer to caught object
 134   __sub_kind part2dst;        // path from current base to target
 135   int src_details;            // hints about the source type hierarchy
 136   const __class_type_info *base_type; // where we found the target,
 137                               // if in vbase the __class_type_info of vbase
 138                               // if a non-virtual base then 1
 139                               // else NULL
 140   __upcast_result (int d)
 141     :dst_ptr (NULL), part2dst (__unknown), src_details (d), base_type (NULL)
 142     {}
 143 };
 144
 145 // __dyncast_result is used to hold information during traversal of a class
 146 // hierarchy when dynamic casting.
 147 struct __class_type_info::__dyncast_result
 148 {
 149   const void *dst_ptr;        // pointer to target object or NULL
 150   __sub_kind whole2dst;       // path from most derived object to target
 151   __sub_kind whole2src;       // path from most derived object to sub object
 152   __sub_kind dst2src;         // path from target to sub object
 153   int whole_details;          // details of the whole class hierarchy
 154
 155   __dyncast_result (int details_ = __vmi_class_type_info::__flags_unknown_mask)
 156     :dst_ptr (NULL), whole2dst (__unknown),
 157      whole2src (__unknown), dst2src (__unknown),
 158      whole_details (details_)
 159     {}
 160
 161 protected:
 162   __dyncast_result(const __dyncast_result&);
 163
 164   __dyncast_result&
 165   operator=(const __dyncast_result&);
 166 };
 167
 168 inline __class_type_info::__sub_kind __class_type_info::
 169 __find_public_src (ptrdiff_t src2dst,
 170                    const void *obj_ptr,
 171                    const __class_type_info *src_type,
 172                    const void *src_ptr) const
 173 {
 174   if (src2dst >= 0)
 175     return adjust_pointer <void> (obj_ptr, src2dst) == src_ptr
 176             ? __contained_public : __not_contained;
 177   if (src2dst == -2)
 178     return __not_contained;
 179   return __do_find_public_src (src2dst, obj_ptr, src_type, src_ptr);
 180 }
 181
 182 }