typeinfo.h revision 299143
1/* 2 * Copyright 2010-2011 PathScale, Inc. All rights reserved. 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions are met: 6 * 7 * 1. Redistributions of source code must retain the above copyright notice, 8 * this list of conditions and the following disclaimer. 9 * 10 * 2. Redistributions in binary form must reproduce the above copyright notice, 11 * this list of conditions and the following disclaimer in the documentation 12 * and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS 15 * IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, 16 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 17 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR 18 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 19 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 20 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; 21 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 22 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR 23 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF 24 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25 */ 26 27#include <stddef.h> 28#include "abi_namespace.h" 29 30namespace ABI_NAMESPACE 31{ 32 struct __class_type_info; 33} 34namespace std 35{ 36 /** 37 * Standard type info class. The layout of this class is specified by the 38 * ABI. The layout of the vtable is not, but is intended to be 39 * compatible with the GNU ABI. 40 * 41 * Unlike the GNU version, the vtable layout is considered semi-private. 42 */ 43 class type_info 44 { 45 public: 46 /** 47 * Virtual destructor. This class must have one virtual function to 48 * ensure that it has a vtable. 49 */ 50 virtual ~type_info(); 51 bool operator==(const type_info &) const; 52 bool operator!=(const type_info &) const; 53 bool before(const type_info &) const; 54 const char* name() const; 55 type_info(); 56 private: 57 type_info(const type_info& rhs); 58 type_info& operator= (const type_info& rhs); 59 const char *__type_name; 60 /* 61 * The following functions are in this order to match the 62 * vtable layout of libsupc++. This allows libcxxrt to be used 63 * with libraries that depend on this. 64 * 65 * These functions are in the public headers for libstdc++, so 66 * we have to assume that someone will probably call them and 67 * expect them to work. Their names must also match the names used in 68 * libsupc++, so that code linking against this library can subclass 69 * type_info and correctly fill in the values in the vtables. 70 */ 71 public: 72 /** 73 * Returns true if this is some pointer type, false otherwise. 74 */ 75 virtual bool __is_pointer_p() const { return false; } 76 /** 77 * Returns true if this is some function type, false otherwise. 78 */ 79 virtual bool __is_function_p() const { return false; } 80 /** 81 * Catch function. Allows external libraries to implement 82 * their own basic types. This is used, for example, in the 83 * GNUstep Objective-C runtime to allow Objective-C types to be 84 * caught in G++ catch blocks. 85 * 86 * The outer parameter indicates the number of outer pointers 87 * in the high bits. The low bit indicates whether the 88 * pointers are const qualified. 89 */ 90 virtual bool __do_catch(const type_info *thrown_type, 91 void **thrown_object, 92 unsigned outer) const; 93 /** 94 * Performs an upcast. This is used in exception handling to 95 * cast from subclasses to superclasses. If the upcast is 96 * possible, it returns true and adjusts the pointer. If the 97 * upcast is not possible, it returns false and does not adjust 98 * the pointer. 99 */ 100 virtual bool __do_upcast( 101 const ABI_NAMESPACE::__class_type_info *target, 102 void **thrown_object) const 103 { 104 return false; 105 } 106 }; 107} 108 109 110namespace ABI_NAMESPACE 111{ 112 /** 113 * Primitive type info, for intrinsic types. 114 */ 115 struct __fundamental_type_info : public std::type_info 116 { 117 virtual ~__fundamental_type_info(); 118 }; 119 /** 120 * Type info for arrays. 121 */ 122 struct __array_type_info : public std::type_info 123 { 124 virtual ~__array_type_info(); 125 }; 126 /** 127 * Type info for functions. 128 */ 129 struct __function_type_info : public std::type_info 130 { 131 virtual ~__function_type_info(); 132 virtual bool __is_function_p() const { return true; } 133 }; 134 /** 135 * Type info for enums. 136 */ 137 struct __enum_type_info : public std::type_info 138 { 139 virtual ~__enum_type_info(); 140 }; 141 142 /** 143 * Base class for class type info. Used only for tentative definitions. 144 */ 145 struct __class_type_info : public std::type_info 146 { 147 virtual ~__class_type_info(); 148 /** 149 * Function implementing dynamic casts. 150 */ 151 virtual void *cast_to(void *obj, const struct __class_type_info *other) const; 152 virtual bool __do_upcast(const __class_type_info *target, 153 void **thrown_object) const 154 { 155 return this == target; 156 } 157 }; 158 159 /** 160 * Single-inheritance class type info. This is used for classes containing 161 * a single non-virtual base class at offset 0. 162 */ 163 struct __si_class_type_info : public __class_type_info 164 { 165 virtual ~__si_class_type_info(); 166 const __class_type_info *__base_type; 167 virtual bool __do_upcast( 168 const ABI_NAMESPACE::__class_type_info *target, 169 void **thrown_object) const; 170 virtual void *cast_to(void *obj, const struct __class_type_info *other) const; 171 }; 172 173 /** 174 * Type info for base classes. Classes with multiple bases store an array 175 * of these, one for each superclass. 176 */ 177 struct __base_class_type_info 178 { 179 const __class_type_info *__base_type; 180 private: 181 /** 182 * The high __offset_shift bits of this store the (signed) offset 183 * of the base class. The low bits store flags from 184 * __offset_flags_masks. 185 */ 186 long __offset_flags; 187 /** 188 * Flags used in the low bits of __offset_flags. 189 */ 190 enum __offset_flags_masks 191 { 192 /** This base class is virtual. */ 193 __virtual_mask = 0x1, 194 /** This base class is public. */ 195 __public_mask = 0x2, 196 /** The number of bits reserved for flags. */ 197 __offset_shift = 8 198 }; 199 public: 200 /** 201 * Returns the offset of the base class. 202 */ 203 long offset() const 204 { 205 return __offset_flags >> __offset_shift; 206 } 207 /** 208 * Returns the flags. 209 */ 210 long flags() const 211 { 212 return __offset_flags & ((1 << __offset_shift) - 1); 213 } 214 /** 215 * Returns whether this is a public base class. 216 */ 217 bool isPublic() const { return flags() & __public_mask; } 218 /** 219 * Returns whether this is a virtual base class. 220 */ 221 bool isVirtual() const { return flags() & __virtual_mask; } 222 }; 223 224 /** 225 * Type info for classes with virtual bases or multiple superclasses. 226 */ 227 struct __vmi_class_type_info : public __class_type_info 228 { 229 virtual ~__vmi_class_type_info(); 230 /** Flags describing this class. Contains values from __flags_masks. */ 231 unsigned int __flags; 232 /** The number of base classes. */ 233 unsigned int __base_count; 234 /** 235 * Array of base classes - this actually has __base_count elements, not 236 * 1. 237 */ 238 __base_class_type_info __base_info[1]; 239 240 /** 241 * Flags used in the __flags field. 242 */ 243 enum __flags_masks 244 { 245 /** The class has non-diamond repeated inheritance. */ 246 __non_diamond_repeat_mask = 0x1, 247 /** The class is diamond shaped. */ 248 __diamond_shaped_mask = 0x2 249 }; 250 virtual bool __do_upcast( 251 const ABI_NAMESPACE::__class_type_info *target, 252 void **thrown_object) const; 253 virtual void *cast_to(void *obj, const struct __class_type_info *other) const; 254 }; 255 256 /** 257 * Base class used for both pointer and pointer-to-member type info. 258 */ 259 struct __pbase_type_info : public std::type_info 260 { 261 virtual ~__pbase_type_info(); 262 /** 263 * Flags. Values from __masks. 264 */ 265 unsigned int __flags; 266 /** 267 * The type info for the pointee. 268 */ 269 const std::type_info *__pointee; 270 271 /** 272 * Masks used for qualifiers on the pointer. 273 */ 274 enum __masks 275 { 276 /** Pointer has const qualifier. */ 277 __const_mask = 0x1, 278 /** Pointer has volatile qualifier. */ 279 __volatile_mask = 0x2, 280 /** Pointer has restrict qualifier. */ 281 __restrict_mask = 0x4, 282 /** Pointer points to an incomplete type. */ 283 __incomplete_mask = 0x8, 284 /** Pointer is a pointer to a member of an incomplete class. */ 285 __incomplete_class_mask = 0x10 286 }; 287 virtual bool __do_catch(const type_info *thrown_type, 288 void **thrown_object, 289 unsigned outer) const; 290 }; 291 292 /** 293 * Pointer type info. 294 */ 295 struct __pointer_type_info : public __pbase_type_info 296 { 297 virtual ~__pointer_type_info(); 298 virtual bool __is_pointer_p() const { return true; } 299 }; 300 301 /** 302 * Pointer to member type info. 303 */ 304 struct __pointer_to_member_type_info : public __pbase_type_info 305 { 306 virtual ~__pointer_to_member_type_info(); 307 /** 308 * Pointer to the class containing this member. 309 */ 310 const __class_type_info *__context; 311 }; 312 313} 314