1 /* 2 * Copyright 2012 David Chisnall. All rights reserved. 3 * 4 * Permission is hereby granted, free of charge, to any person obtaining a copy 5 * of this software and associated documentation files (the "Software"), to 6 * deal in the Software without restriction, including without limitation the 7 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or 8 * sell copies of the Software, and to permit persons to whom the Software is 9 * furnished to do so, subject to the following conditions: 10 * 11 * The above copyright notice and this permission notice shall be 12 * included in all copies or substantial portions of the Software. 13 * 14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 15 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF 16 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND 17 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE 18 * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION 19 * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION 20 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. 21 */ 22 23 #ifndef __CXXABI_H_ 24 #define __CXXABI_H_ 25 #include <stdint.h> 26 #include "unwind.h" 27 namespace std 28 { 29 class type_info; 30 } 31 /* 32 * The cxxabi.h header provides a set of public definitions for types and 33 * functions defined by the Itanium C++ ABI specification. For reference, see 34 * the ABI specification here: 35 * 36 * http://sourcery.mentor.com/public/cxx-abi/abi.html 37 * 38 * All deviations from this specification, unless otherwise noted, are 39 * accidental. 40 */ 41 42 #ifdef __cplusplus 43 namespace __cxxabiv1 { 44 extern "C" { 45 #endif 46 /** 47 * Function type to call when an unexpected exception is encountered. 48 */ 49 typedef void (*unexpected_handler)(); 50 /** 51 * Function type to call when an unrecoverable condition is encountered. 52 */ 53 typedef void (*terminate_handler)(); 54 55 56 /** 57 * Structure used as a header on thrown exceptions. This is the same layout as 58 * defined by the Itanium ABI spec, so should be interoperable with any other 59 * implementation of this spec, such as GNU libsupc++. 60 * 61 * This structure is allocated when an exception is thrown. Unwinding happens 62 * in two phases, the first looks for a handler and the second installs the 63 * context. This structure stores a cache of the handler location between 64 * phase 1 and phase 2. Unfortunately, cleanup information is not cached, so 65 * must be looked up in both phases. This happens for two reasons. The first 66 * is that we don't know how many frames containing cleanups there will be, and 67 * we should avoid dynamic allocation during unwinding (the exception may be 68 * reporting that we've run out of memory). The second is that finding 69 * cleanups is much cheaper than finding handlers, because we don't have to 70 * look at the type table at all. 71 * 72 * Note: Several fields of this structure have not-very-informative names. 73 * These are taken from the ABI spec and have not been changed to make it 74 * easier for people referring to to the spec while reading this code. 75 */ 76 struct __cxa_exception 77 { 78 #if __LP64__ 79 /** 80 * Reference count. Used to support the C++11 exception_ptr class. This 81 * is prepended to the structure in 64-bit mode and squeezed in to the 82 * padding left before the 64-bit aligned _Unwind_Exception at the end in 83 * 32-bit mode. 84 * 85 * Note that it is safe to extend this structure at the beginning, rather 86 * than the end, because the public API for creating it returns the address 87 * of the end (where the exception object can be stored). 88 */ 89 uintptr_t referenceCount; 90 #endif 91 /** Type info for the thrown object. */ 92 std::type_info *exceptionType; 93 /** Destructor for the object, if one exists. */ 94 void (*exceptionDestructor) (void *); 95 /** Handler called when an exception specification is violated. */ 96 unexpected_handler unexpectedHandler; 97 /** Hander called to terminate. */ 98 terminate_handler terminateHandler; 99 /** 100 * Next exception in the list. If an exception is thrown inside a catch 101 * block and caught in a nested catch, this points to the exception that 102 * will be handled after the inner catch block completes. 103 */ 104 __cxa_exception *nextException; 105 /** 106 * The number of handlers that currently have references to this 107 * exception. The top (non-sign) bit of this is used as a flag to indicate 108 * that the exception is being rethrown, so should not be deleted when its 109 * handler count reaches 0 (which it doesn't with the top bit set). 110 */ 111 int handlerCount; 112 #ifdef __arm__ 113 /** 114 * The ARM EH ABI requires the unwind library to keep track of exceptions 115 * during cleanups. These support nesting, so we need to keep a list of 116 * them. 117 */ 118 _Unwind_Exception *nextCleanup; 119 /** 120 * The number of cleanups that are currently being run on this exception. 121 */ 122 int cleanupCount; 123 #endif 124 /** 125 * The selector value to be returned when installing the catch handler. 126 * Used at the call site to determine which catch() block should execute. 127 * This is found in phase 1 of unwinding then installed in phase 2. 128 */ 129 int handlerSwitchValue; 130 /** 131 * The action record for the catch. This is cached during phase 1 132 * unwinding. 133 */ 134 const char *actionRecord; 135 /** 136 * Pointer to the language-specific data area (LSDA) for the handler 137 * frame. This is unused in this implementation, but set for ABI 138 * compatibility in case we want to mix code in very weird ways. 139 */ 140 const char *languageSpecificData; 141 /** The cached landing pad for the catch handler.*/ 142 void *catchTemp; 143 /** 144 * The pointer that will be returned as the pointer to the object. When 145 * throwing a class and catching a virtual superclass (for example), we 146 * need to adjust the thrown pointer to make it all work correctly. 147 */ 148 void *adjustedPtr; 149 #if !__LP64__ 150 /** 151 * Reference count. Used to support the C++11 exception_ptr class. This 152 * is prepended to the structure in 64-bit mode and squeezed in to the 153 * padding left before the 64-bit aligned _Unwind_Exception at the end in 154 * 32-bit mode. 155 * 156 * Note that it is safe to extend this structure at the beginning, rather 157 * than the end, because the public API for creating it returns the address 158 * of the end (where the exception object can be stored) 159 */ 160 uintptr_t referenceCount; 161 #endif 162 /** The language-agnostic part of the exception header. */ 163 _Unwind_Exception unwindHeader; 164 }; 165 166 /** 167 * ABI-specified globals structure. Returned by the __cxa_get_globals() 168 * function and its fast variant. This is a per-thread structure - every 169 * thread will have one lazily allocated. 170 * 171 * This structure is defined by the ABI, so may be used outside of this 172 * library. 173 */ 174 struct __cxa_eh_globals 175 { 176 /** 177 * A linked list of exceptions that are currently caught. There may be 178 * several of these in nested catch() blocks. 179 */ 180 __cxa_exception *caughtExceptions; 181 /** 182 * The number of uncaught exceptions. 183 */ 184 unsigned int uncaughtExceptions; 185 }; 186 /** 187 * ABI function returning the __cxa_eh_globals structure. 188 */ 189 __cxa_eh_globals *__cxa_get_globals(void); 190 /** 191 * Version of __cxa_get_globals() assuming that __cxa_get_globals() has already 192 * been called at least once by this thread. 193 */ 194 __cxa_eh_globals *__cxa_get_globals_fast(void); 195 196 std::type_info * __cxa_current_exception_type(); 197 198 /** 199 * Throws an exception returned by __cxa_current_primary_exception(). This 200 * exception may have been caught in another thread. 201 */ 202 void __cxa_rethrow_primary_exception(void* thrown_exception); 203 /** 204 * Returns the current exception in a form that can be stored in an 205 * exception_ptr object and then rethrown by a call to 206 * __cxa_rethrow_primary_exception(). 207 */ 208 void *__cxa_current_primary_exception(void); 209 /** 210 * Increments the reference count of an exception. Called when an 211 * exception_ptr is copied. 212 */ 213 void __cxa_increment_exception_refcount(void* thrown_exception); 214 /** 215 * Decrements the reference count of an exception. Called when an 216 * exception_ptr is deleted. 217 */ 218 void __cxa_decrement_exception_refcount(void* thrown_exception); 219 /** 220 * Demangles a C++ symbol or type name. The buffer, if non-NULL, must be 221 * allocated with malloc() and must be *n bytes or more long. This function 222 * may call realloc() on the value pointed to by buf, and will return the 223 * length of the string via *n. 224 * 225 * The value pointed to by status is set to one of the following: 226 * 227 * 0: success 228 * -1: memory allocation failure 229 * -2: invalid mangled name 230 * -3: invalid arguments 231 */ 232 char* __cxa_demangle(const char* mangled_name, 233 char* buf, 234 size_t* n, 235 int* status); 236 #ifdef __cplusplus 237 } // extern "C" 238 } // namespace 239 240 namespace abi = __cxxabiv1; 241 242 #endif /* __cplusplus */ 243 #endif /* __CXXABI_H_ */ 244