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 <stdlib.h> 28 #include <dlfcn.h> 29 #include <stdio.h> 30 #include <string.h> 31 #include <stdint.h> 32 #include <pthread.h> 33 #include "typeinfo.h" 34 #include "dwarf_eh.h" 35 #include "atomic.h" 36 #include "cxxabi.h" 37 38 #pragma weak pthread_key_create 39 #pragma weak pthread_setspecific 40 #pragma weak pthread_getspecific 41 #pragma weak pthread_once 42 #ifdef LIBCXXRT_WEAK_LOCKS 43 #pragma weak pthread_mutex_lock 44 #define pthread_mutex_lock(mtx) do {\ 45 if (pthread_mutex_lock) pthread_mutex_lock(mtx);\ 46 } while(0) 47 #pragma weak pthread_mutex_unlock 48 #define pthread_mutex_unlock(mtx) do {\ 49 if (pthread_mutex_unlock) pthread_mutex_unlock(mtx);\ 50 } while(0) 51 #pragma weak pthread_cond_signal 52 #define pthread_cond_signal(cv) do {\ 53 if (pthread_cond_signal) pthread_cond_signal(cv);\ 54 } while(0) 55 #pragma weak pthread_cond_wait 56 #define pthread_cond_wait(cv, mtx) do {\ 57 if (pthread_cond_wait) pthread_cond_wait(cv, mtx);\ 58 } while(0) 59 #endif 60 61 using namespace ABI_NAMESPACE; 62 63 /** 64 * Saves the result of the landing pad that we have found. For ARM, this is 65 * stored in the generic unwind structure, while on other platforms it is 66 * stored in the C++ exception. 67 */ 68 static void saveLandingPad(struct _Unwind_Context *context, 69 struct _Unwind_Exception *ucb, 70 struct __cxa_exception *ex, 71 int selector, 72 dw_eh_ptr_t landingPad) 73 { 74 #if defined(__arm__) && !defined(__ARM_DWARF_EH__) 75 // On ARM, we store the saved exception in the generic part of the structure 76 ucb->barrier_cache.sp = _Unwind_GetGR(context, 13); 77 ucb->barrier_cache.bitpattern[1] = static_cast<uint32_t>(selector); 78 ucb->barrier_cache.bitpattern[3] = reinterpret_cast<uint32_t>(landingPad); 79 #endif 80 // Cache the results for the phase 2 unwind, if we found a handler 81 // and this is not a foreign exception. 82 if (ex) 83 { 84 ex->handlerSwitchValue = selector; 85 ex->catchTemp = landingPad; 86 } 87 } 88 89 /** 90 * Loads the saved landing pad. Returns 1 on success, 0 on failure. 91 */ 92 static int loadLandingPad(struct _Unwind_Context *context, 93 struct _Unwind_Exception *ucb, 94 struct __cxa_exception *ex, 95 unsigned long *selector, 96 dw_eh_ptr_t *landingPad) 97 { 98 #if defined(__arm__) && !defined(__ARM_DWARF_EH__) 99 *selector = ucb->barrier_cache.bitpattern[1]; 100 *landingPad = reinterpret_cast<dw_eh_ptr_t>(ucb->barrier_cache.bitpattern[3]); 101 return 1; 102 #else 103 if (ex) 104 { 105 *selector = ex->handlerSwitchValue; 106 *landingPad = reinterpret_cast<dw_eh_ptr_t>(ex->catchTemp); 107 return 0; 108 } 109 return 0; 110 #endif 111 } 112 113 static inline _Unwind_Reason_Code continueUnwinding(struct _Unwind_Exception *ex, 114 struct _Unwind_Context *context) 115 { 116 #if defined(__arm__) && !defined(__ARM_DWARF_EH__) 117 if (__gnu_unwind_frame(ex, context) != _URC_OK) { return _URC_FAILURE; } 118 #endif 119 return _URC_CONTINUE_UNWIND; 120 } 121 122 123 extern "C" void __cxa_free_exception(void *thrown_exception); 124 extern "C" void __cxa_free_dependent_exception(void *thrown_exception); 125 extern "C" void* __dynamic_cast(const void *sub, 126 const __class_type_info *src, 127 const __class_type_info *dst, 128 ptrdiff_t src2dst_offset); 129 130 /** 131 * The type of a handler that has been found. 132 */ 133 typedef enum 134 { 135 /** No handler. */ 136 handler_none, 137 /** 138 * A cleanup - the exception will propagate through this frame, but code 139 * must be run when this happens. 140 */ 141 handler_cleanup, 142 /** 143 * A catch statement. The exception will not propagate past this frame 144 * (without an explicit rethrow). 145 */ 146 handler_catch 147 } handler_type; 148 149 /** 150 * Per-thread info required by the runtime. We store a single structure 151 * pointer in thread-local storage, because this tends to be a scarce resource 152 * and it's impolite to steal all of it and not leave any for the rest of the 153 * program. 154 * 155 * Instances of this structure are allocated lazily - at most one per thread - 156 * and are destroyed on thread termination. 157 */ 158 struct __cxa_thread_info 159 { 160 /** The termination handler for this thread. */ 161 terminate_handler terminateHandler; 162 /** The unexpected exception handler for this thread. */ 163 unexpected_handler unexpectedHandler; 164 /** 165 * The number of emergency buffers held by this thread. This is 0 in 166 * normal operation - the emergency buffers are only used when malloc() 167 * fails to return memory for allocating an exception. Threads are not 168 * permitted to hold more than 4 emergency buffers (as per recommendation 169 * in ABI spec [3.3.1]). 170 */ 171 int emergencyBuffersHeld; 172 /** 173 * The exception currently running in a cleanup. 174 */ 175 _Unwind_Exception *currentCleanup; 176 /** 177 * Our state with respect to foreign exceptions. Usually none, set to 178 * caught if we have just caught an exception and rethrown if we are 179 * rethrowing it. 180 */ 181 enum 182 { 183 none, 184 caught, 185 rethrown 186 } foreign_exception_state; 187 /** 188 * The public part of this structure, accessible from outside of this 189 * module. 190 */ 191 __cxa_eh_globals globals; 192 }; 193 /** 194 * Dependent exception. This 195 */ 196 struct __cxa_dependent_exception 197 { 198 #if __LP64__ 199 void *primaryException; 200 #endif 201 std::type_info *exceptionType; 202 void (*exceptionDestructor) (void *); 203 unexpected_handler unexpectedHandler; 204 terminate_handler terminateHandler; 205 __cxa_exception *nextException; 206 int handlerCount; 207 #if defined(__arm__) && !defined(__ARM_DWARF_EH__) 208 _Unwind_Exception *nextCleanup; 209 int cleanupCount; 210 #endif 211 int handlerSwitchValue; 212 const char *actionRecord; 213 const char *languageSpecificData; 214 void *catchTemp; 215 void *adjustedPtr; 216 #if !__LP64__ 217 void *primaryException; 218 #endif 219 _Unwind_Exception unwindHeader; 220 }; 221 222 223 namespace std 224 { 225 void unexpected(); 226 class exception 227 { 228 public: 229 virtual ~exception() throw(); 230 virtual const char* what() const throw(); 231 }; 232 233 } 234 235 /** 236 * Class of exceptions to distinguish between this and other exception types. 237 * 238 * The first four characters are the vendor ID. Currently, we use GNUC, 239 * because we aim for ABI-compatibility with the GNU implementation, and 240 * various checks may test for equality of the class, which is incorrect. 241 */ 242 static const uint64_t exception_class = 243 EXCEPTION_CLASS('G', 'N', 'U', 'C', 'C', '+', '+', '\0'); 244 /** 245 * Class used for dependent exceptions. 246 */ 247 static const uint64_t dependent_exception_class = 248 EXCEPTION_CLASS('G', 'N', 'U', 'C', 'C', '+', '+', '\x01'); 249 /** 250 * The low four bytes of the exception class, indicating that we conform to the 251 * Itanium C++ ABI. This is currently unused, but should be used in the future 252 * if we change our exception class, to allow this library and libsupc++ to be 253 * linked to the same executable and both to interoperate. 254 */ 255 static const uint32_t abi_exception_class = 256 GENERIC_EXCEPTION_CLASS('C', '+', '+', '\0'); 257 258 static bool isCXXException(uint64_t cls) 259 { 260 return (cls == exception_class) || (cls == dependent_exception_class); 261 } 262 263 static bool isDependentException(uint64_t cls) 264 { 265 return cls == dependent_exception_class; 266 } 267 268 static __cxa_exception *exceptionFromPointer(void *ex) 269 { 270 return reinterpret_cast<__cxa_exception*>(static_cast<char*>(ex) - 271 offsetof(struct __cxa_exception, unwindHeader)); 272 } 273 static __cxa_exception *realExceptionFromException(__cxa_exception *ex) 274 { 275 if (!isDependentException(ex->unwindHeader.exception_class)) { return ex; } 276 return reinterpret_cast<__cxa_exception*>((reinterpret_cast<__cxa_dependent_exception*>(ex))->primaryException)-1; 277 } 278 279 280 namespace std 281 { 282 // Forward declaration of standard library terminate() function used to 283 // abort execution. 284 void terminate(void); 285 } 286 287 using namespace ABI_NAMESPACE; 288 289 290 291 /** The global termination handler. */ 292 static terminate_handler terminateHandler = abort; 293 /** The global unexpected exception handler. */ 294 static unexpected_handler unexpectedHandler = std::terminate; 295 296 /** Key used for thread-local data. */ 297 static pthread_key_t eh_key; 298 299 300 /** 301 * Cleanup function, allowing foreign exception handlers to correctly destroy 302 * this exception if they catch it. 303 */ 304 static void exception_cleanup(_Unwind_Reason_Code reason, 305 struct _Unwind_Exception *ex) 306 { 307 __cxa_free_exception(static_cast<void*>(ex)); 308 } 309 static void dependent_exception_cleanup(_Unwind_Reason_Code reason, 310 struct _Unwind_Exception *ex) 311 { 312 313 __cxa_free_dependent_exception(static_cast<void*>(ex)); 314 } 315 316 /** 317 * Recursively walk a list of exceptions and delete them all in post-order. 318 */ 319 static void free_exception_list(__cxa_exception *ex) 320 { 321 if (0 != ex->nextException) 322 { 323 free_exception_list(ex->nextException); 324 } 325 // __cxa_free_exception() expects to be passed the thrown object, which 326 // immediately follows the exception, not the exception itself 327 __cxa_free_exception(ex+1); 328 } 329 330 /** 331 * Cleanup function called when a thread exists to make certain that all of the 332 * per-thread data is deleted. 333 */ 334 static void thread_cleanup(void* thread_info) 335 { 336 __cxa_thread_info *info = static_cast<__cxa_thread_info*>(thread_info); 337 if (info->globals.caughtExceptions) 338 { 339 // If this is a foreign exception, ask it to clean itself up. 340 if (info->foreign_exception_state != __cxa_thread_info::none) 341 { 342 _Unwind_Exception *e = reinterpret_cast<_Unwind_Exception*>(info->globals.caughtExceptions); 343 e->exception_cleanup(_URC_FOREIGN_EXCEPTION_CAUGHT, e); 344 } 345 else 346 { 347 free_exception_list(info->globals.caughtExceptions); 348 } 349 } 350 free(thread_info); 351 } 352 353 354 /** 355 * Once control used to protect the key creation. 356 */ 357 static pthread_once_t once_control = PTHREAD_ONCE_INIT; 358 359 /** 360 * We may not be linked against a full pthread implementation. If we're not, 361 * then we need to fake the thread-local storage by storing 'thread-local' 362 * things in a global. 363 */ 364 static bool fakeTLS; 365 /** 366 * Thread-local storage for a single-threaded program. 367 */ 368 static __cxa_thread_info singleThreadInfo; 369 /** 370 * Initialise eh_key. 371 */ 372 static void init_key(void) 373 { 374 if ((0 == pthread_key_create) || 375 (0 == pthread_setspecific) || 376 (0 == pthread_getspecific)) 377 { 378 fakeTLS = true; 379 return; 380 } 381 pthread_key_create(&eh_key, thread_cleanup); 382 pthread_setspecific(eh_key, reinterpret_cast<void *>(0x42)); 383 fakeTLS = (pthread_getspecific(eh_key) != reinterpret_cast<void *>(0x42)); 384 pthread_setspecific(eh_key, 0); 385 } 386 387 /** 388 * Returns the thread info structure, creating it if it is not already created. 389 */ 390 static __cxa_thread_info *thread_info() 391 { 392 if ((0 == pthread_once) || pthread_once(&once_control, init_key)) 393 { 394 fakeTLS = true; 395 } 396 if (fakeTLS) { return &singleThreadInfo; } 397 __cxa_thread_info *info = static_cast<__cxa_thread_info*>(pthread_getspecific(eh_key)); 398 if (0 == info) 399 { 400 info = static_cast<__cxa_thread_info*>(calloc(1, sizeof(__cxa_thread_info))); 401 pthread_setspecific(eh_key, info); 402 } 403 return info; 404 } 405 /** 406 * Fast version of thread_info(). May fail if thread_info() is not called on 407 * this thread at least once already. 408 */ 409 static __cxa_thread_info *thread_info_fast() 410 { 411 if (fakeTLS) { return &singleThreadInfo; } 412 return static_cast<__cxa_thread_info*>(pthread_getspecific(eh_key)); 413 } 414 /** 415 * ABI function returning the __cxa_eh_globals structure. 416 */ 417 extern "C" __cxa_eh_globals *ABI_NAMESPACE::__cxa_get_globals(void) 418 { 419 return &(thread_info()->globals); 420 } 421 /** 422 * Version of __cxa_get_globals() assuming that __cxa_get_globals() has already 423 * been called at least once by this thread. 424 */ 425 extern "C" __cxa_eh_globals *ABI_NAMESPACE::__cxa_get_globals_fast(void) 426 { 427 return &(thread_info_fast()->globals); 428 } 429 430 /** 431 * An emergency allocation reserved for when malloc fails. This is treated as 432 * 16 buffers of 1KB each. 433 */ 434 static char emergency_buffer[16384]; 435 /** 436 * Flag indicating whether each buffer is allocated. 437 */ 438 static bool buffer_allocated[16]; 439 /** 440 * Lock used to protect emergency allocation. 441 */ 442 static pthread_mutex_t emergency_malloc_lock = PTHREAD_MUTEX_INITIALIZER; 443 /** 444 * Condition variable used to wait when two threads are both trying to use the 445 * emergency malloc() buffer at once. 446 */ 447 static pthread_cond_t emergency_malloc_wait = PTHREAD_COND_INITIALIZER; 448 449 /** 450 * Allocates size bytes from the emergency allocation mechanism, if possible. 451 * This function will fail if size is over 1KB or if this thread already has 4 452 * emergency buffers. If all emergency buffers are allocated, it will sleep 453 * until one becomes available. 454 */ 455 static char *emergency_malloc(size_t size) 456 { 457 if (size > 1024) { return 0; } 458 459 __cxa_thread_info *info = thread_info(); 460 // Only 4 emergency buffers allowed per thread! 461 if (info->emergencyBuffersHeld > 3) { return 0; } 462 463 pthread_mutex_lock(&emergency_malloc_lock); 464 int buffer = -1; 465 while (buffer < 0) 466 { 467 // While we were sleeping on the lock, another thread might have free'd 468 // enough memory for us to use, so try the allocation again - no point 469 // using the emergency buffer if there is some real memory that we can 470 // use... 471 void *m = calloc(1, size); 472 if (0 != m) 473 { 474 pthread_mutex_unlock(&emergency_malloc_lock); 475 return static_cast<char*>(m); 476 } 477 for (int i=0 ; i<16 ; i++) 478 { 479 if (!buffer_allocated[i]) 480 { 481 buffer = i; 482 buffer_allocated[i] = true; 483 break; 484 } 485 } 486 // If there still isn't a buffer available, then sleep on the condition 487 // variable. This will be signalled when another thread releases one 488 // of the emergency buffers. 489 if (buffer < 0) 490 { 491 pthread_cond_wait(&emergency_malloc_wait, &emergency_malloc_lock); 492 } 493 } 494 pthread_mutex_unlock(&emergency_malloc_lock); 495 info->emergencyBuffersHeld++; 496 return emergency_buffer + (1024 * buffer); 497 } 498 499 /** 500 * Frees a buffer returned by emergency_malloc(). 501 * 502 * Note: Neither this nor emergency_malloc() is particularly efficient. This 503 * should not matter, because neither will be called in normal operation - they 504 * are only used when the program runs out of memory, which should not happen 505 * often. 506 */ 507 static void emergency_malloc_free(char *ptr) 508 { 509 int buffer = -1; 510 // Find the buffer corresponding to this pointer. 511 for (int i=0 ; i<16 ; i++) 512 { 513 if (ptr == static_cast<void*>(emergency_buffer + (1024 * i))) 514 { 515 buffer = i; 516 break; 517 } 518 } 519 assert(buffer > 0 && 520 "Trying to free something that is not an emergency buffer!"); 521 // emergency_malloc() is expected to return 0-initialized data. We don't 522 // zero the buffer when allocating it, because the static buffers will 523 // begin life containing 0 values. 524 memset(ptr, 0, 1024); 525 // Signal the condition variable to wake up any threads that are blocking 526 // waiting for some space in the emergency buffer 527 pthread_mutex_lock(&emergency_malloc_lock); 528 // In theory, we don't need to do this with the lock held. In practice, 529 // our array of bools will probably be updated using 32-bit or 64-bit 530 // memory operations, so this update may clobber adjacent values. 531 buffer_allocated[buffer] = false; 532 pthread_cond_signal(&emergency_malloc_wait); 533 pthread_mutex_unlock(&emergency_malloc_lock); 534 } 535 536 static char *alloc_or_die(size_t size) 537 { 538 char *buffer = static_cast<char*>(calloc(1, size)); 539 540 // If calloc() doesn't want to give us any memory, try using an emergency 541 // buffer. 542 if (0 == buffer) 543 { 544 buffer = emergency_malloc(size); 545 // This is only reached if the allocation is greater than 1KB, and 546 // anyone throwing objects that big really should know better. 547 if (0 == buffer) 548 { 549 fprintf(stderr, "Out of memory attempting to allocate exception\n"); 550 std::terminate(); 551 } 552 } 553 return buffer; 554 } 555 static void free_exception(char *e) 556 { 557 // If this allocation is within the address range of the emergency buffer, 558 // don't call free() because it was not allocated with malloc() 559 if ((e > emergency_buffer) && 560 (e < (emergency_buffer + sizeof(emergency_buffer)))) 561 { 562 emergency_malloc_free(e); 563 } 564 else 565 { 566 free(e); 567 } 568 } 569 570 /** 571 * Allocates an exception structure. Returns a pointer to the space that can 572 * be used to store an object of thrown_size bytes. This function will use an 573 * emergency buffer if malloc() fails, and may block if there are no such 574 * buffers available. 575 */ 576 extern "C" void *__cxa_allocate_exception(size_t thrown_size) 577 { 578 size_t size = thrown_size + sizeof(__cxa_exception); 579 char *buffer = alloc_or_die(size); 580 return buffer+sizeof(__cxa_exception); 581 } 582 583 extern "C" void *__cxa_allocate_dependent_exception(void) 584 { 585 size_t size = sizeof(__cxa_dependent_exception); 586 char *buffer = alloc_or_die(size); 587 return buffer+sizeof(__cxa_dependent_exception); 588 } 589 590 /** 591 * __cxa_free_exception() is called when an exception was thrown in between 592 * calling __cxa_allocate_exception() and actually throwing the exception. 593 * This happens when the object's copy constructor throws an exception. 594 * 595 * In this implementation, it is also called by __cxa_end_catch() and during 596 * thread cleanup. 597 */ 598 extern "C" void __cxa_free_exception(void *thrown_exception) 599 { 600 __cxa_exception *ex = reinterpret_cast<__cxa_exception*>(thrown_exception) - 1; 601 // Free the object that was thrown, calling its destructor 602 if (0 != ex->exceptionDestructor) 603 { 604 try 605 { 606 ex->exceptionDestructor(thrown_exception); 607 } 608 catch(...) 609 { 610 // FIXME: Check that this is really what the spec says to do. 611 std::terminate(); 612 } 613 } 614 615 free_exception(reinterpret_cast<char*>(ex)); 616 } 617 618 static void releaseException(__cxa_exception *exception) 619 { 620 if (isDependentException(exception->unwindHeader.exception_class)) 621 { 622 __cxa_free_dependent_exception(exception+1); 623 return; 624 } 625 if (__sync_sub_and_fetch(&exception->referenceCount, 1) == 0) 626 { 627 // __cxa_free_exception() expects to be passed the thrown object, 628 // which immediately follows the exception, not the exception 629 // itself 630 __cxa_free_exception(exception+1); 631 } 632 } 633 634 void __cxa_free_dependent_exception(void *thrown_exception) 635 { 636 __cxa_dependent_exception *ex = reinterpret_cast<__cxa_dependent_exception*>(thrown_exception) - 1; 637 assert(isDependentException(ex->unwindHeader.exception_class)); 638 if (ex->primaryException) 639 { 640 releaseException(realExceptionFromException(reinterpret_cast<__cxa_exception*>(ex))); 641 } 642 free_exception(reinterpret_cast<char*>(ex)); 643 } 644 645 /** 646 * Callback function used with _Unwind_Backtrace(). 647 * 648 * Prints a stack trace. Used only for debugging help. 649 * 650 * Note: As of FreeBSD 8.1, dladd() still doesn't work properly, so this only 651 * correctly prints function names from public, relocatable, symbols. 652 */ 653 static _Unwind_Reason_Code trace(struct _Unwind_Context *context, void *c) 654 { 655 Dl_info myinfo; 656 int mylookup = 657 dladdr(reinterpret_cast<void *>(__cxa_current_exception_type), &myinfo); 658 void *ip = reinterpret_cast<void*>(_Unwind_GetIP(context)); 659 Dl_info info; 660 if (dladdr(ip, &info) != 0) 661 { 662 if (mylookup == 0 || strcmp(info.dli_fname, myinfo.dli_fname) != 0) 663 { 664 printf("%p:%s() in %s\n", ip, info.dli_sname, info.dli_fname); 665 } 666 } 667 return _URC_CONTINUE_UNWIND; 668 } 669 670 /** 671 * Report a failure that occurred when attempting to throw an exception. 672 * 673 * If the failure happened by falling off the end of the stack without finding 674 * a handler, prints a back trace before aborting. 675 */ 676 #if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 4) 677 extern "C" void *__cxa_begin_catch(void *e) throw(); 678 #else 679 extern "C" void *__cxa_begin_catch(void *e); 680 #endif 681 static void report_failure(_Unwind_Reason_Code err, __cxa_exception *thrown_exception) 682 { 683 switch (err) 684 { 685 default: break; 686 case _URC_FATAL_PHASE1_ERROR: 687 fprintf(stderr, "Fatal error during phase 1 unwinding\n"); 688 break; 689 #if !defined(__arm__) || defined(__ARM_DWARF_EH__) 690 case _URC_FATAL_PHASE2_ERROR: 691 fprintf(stderr, "Fatal error during phase 2 unwinding\n"); 692 break; 693 #endif 694 case _URC_END_OF_STACK: 695 __cxa_begin_catch (&(thrown_exception->unwindHeader)); 696 std::terminate(); 697 fprintf(stderr, "Terminating due to uncaught exception %p", 698 static_cast<void*>(thrown_exception)); 699 thrown_exception = realExceptionFromException(thrown_exception); 700 static const __class_type_info *e_ti = 701 static_cast<const __class_type_info*>(&typeid(std::exception)); 702 const __class_type_info *throw_ti = 703 dynamic_cast<const __class_type_info*>(thrown_exception->exceptionType); 704 if (throw_ti) 705 { 706 std::exception *e = 707 static_cast<std::exception*>(e_ti->cast_to(static_cast<void*>(thrown_exception+1), 708 throw_ti)); 709 if (e) 710 { 711 fprintf(stderr, " '%s'", e->what()); 712 } 713 } 714 715 size_t bufferSize = 128; 716 char *demangled = static_cast<char*>(malloc(bufferSize)); 717 const char *mangled = thrown_exception->exceptionType->name(); 718 int status; 719 demangled = __cxa_demangle(mangled, demangled, &bufferSize, &status); 720 fprintf(stderr, " of type %s\n", 721 status == 0 ? demangled : mangled); 722 if (status == 0) { free(demangled); } 723 // Print a back trace if no handler is found. 724 // TODO: Make this optional 725 #ifndef __arm__ 726 _Unwind_Backtrace(trace, 0); 727 #endif 728 729 // Just abort. No need to call std::terminate for the second time 730 abort(); 731 break; 732 } 733 std::terminate(); 734 } 735 736 static void throw_exception(__cxa_exception *ex) 737 { 738 __cxa_thread_info *info = thread_info(); 739 ex->unexpectedHandler = info->unexpectedHandler; 740 if (0 == ex->unexpectedHandler) 741 { 742 ex->unexpectedHandler = unexpectedHandler; 743 } 744 ex->terminateHandler = info->terminateHandler; 745 if (0 == ex->terminateHandler) 746 { 747 ex->terminateHandler = terminateHandler; 748 } 749 info->globals.uncaughtExceptions++; 750 751 _Unwind_Reason_Code err = _Unwind_RaiseException(&ex->unwindHeader); 752 // The _Unwind_RaiseException() function should not return, it should 753 // unwind the stack past this function. If it does return, then something 754 // has gone wrong. 755 report_failure(err, ex); 756 } 757 758 759 /** 760 * ABI function for throwing an exception. Takes the object to be thrown (the 761 * pointer returned by __cxa_allocate_exception()), the type info for the 762 * pointee, and the destructor (if there is one) as arguments. 763 */ 764 extern "C" void __cxa_throw(void *thrown_exception, 765 std::type_info *tinfo, 766 void(*dest)(void*)) 767 { 768 __cxa_exception *ex = reinterpret_cast<__cxa_exception*>(thrown_exception) - 1; 769 770 ex->referenceCount = 1; 771 ex->exceptionType = tinfo; 772 773 ex->exceptionDestructor = dest; 774 775 ex->unwindHeader.exception_class = exception_class; 776 ex->unwindHeader.exception_cleanup = exception_cleanup; 777 778 throw_exception(ex); 779 } 780 781 extern "C" void __cxa_rethrow_primary_exception(void* thrown_exception) 782 { 783 if (NULL == thrown_exception) { return; } 784 785 __cxa_exception *original = exceptionFromPointer(thrown_exception); 786 __cxa_dependent_exception *ex = reinterpret_cast<__cxa_dependent_exception*>(__cxa_allocate_dependent_exception())-1; 787 788 ex->primaryException = thrown_exception; 789 __cxa_increment_exception_refcount(thrown_exception); 790 791 ex->exceptionType = original->exceptionType; 792 ex->unwindHeader.exception_class = dependent_exception_class; 793 ex->unwindHeader.exception_cleanup = dependent_exception_cleanup; 794 795 throw_exception(reinterpret_cast<__cxa_exception*>(ex)); 796 } 797 798 extern "C" void *__cxa_current_primary_exception(void) 799 { 800 __cxa_eh_globals* globals = __cxa_get_globals(); 801 __cxa_exception *ex = globals->caughtExceptions; 802 803 if (0 == ex) { return NULL; } 804 ex = realExceptionFromException(ex); 805 __sync_fetch_and_add(&ex->referenceCount, 1); 806 return ex + 1; 807 } 808 809 extern "C" void __cxa_increment_exception_refcount(void* thrown_exception) 810 { 811 if (NULL == thrown_exception) { return; } 812 __cxa_exception *ex = static_cast<__cxa_exception*>(thrown_exception) - 1; 813 if (isDependentException(ex->unwindHeader.exception_class)) { return; } 814 __sync_fetch_and_add(&ex->referenceCount, 1); 815 } 816 extern "C" void __cxa_decrement_exception_refcount(void* thrown_exception) 817 { 818 if (NULL == thrown_exception) { return; } 819 __cxa_exception *ex = static_cast<__cxa_exception*>(thrown_exception) - 1; 820 releaseException(ex); 821 } 822 823 /** 824 * ABI function. Rethrows the current exception. Does not remove the 825 * exception from the stack or decrement its handler count - the compiler is 826 * expected to set the landing pad for this function to the end of the catch 827 * block, and then call _Unwind_Resume() to continue unwinding once 828 * __cxa_end_catch() has been called and any cleanup code has been run. 829 */ 830 extern "C" void __cxa_rethrow() 831 { 832 __cxa_thread_info *ti = thread_info(); 833 __cxa_eh_globals *globals = &ti->globals; 834 // Note: We don't remove this from the caught list here, because 835 // __cxa_end_catch will be called when we unwind out of the try block. We 836 // could probably make this faster by providing an alternative rethrow 837 // function and ensuring that all cleanup code is run before calling it, so 838 // we can skip the top stack frame when unwinding. 839 __cxa_exception *ex = globals->caughtExceptions; 840 841 if (0 == ex) 842 { 843 fprintf(stderr, 844 "Attempting to rethrow an exception that doesn't exist!\n"); 845 std::terminate(); 846 } 847 848 if (ti->foreign_exception_state != __cxa_thread_info::none) 849 { 850 ti->foreign_exception_state = __cxa_thread_info::rethrown; 851 _Unwind_Exception *e = reinterpret_cast<_Unwind_Exception*>(ex); 852 _Unwind_Reason_Code err = _Unwind_Resume_or_Rethrow(e); 853 report_failure(err, ex); 854 return; 855 } 856 857 assert(ex->handlerCount > 0 && "Rethrowing uncaught exception!"); 858 859 // ex->handlerCount will be decremented in __cxa_end_catch in enclosing 860 // catch block 861 862 // Make handler count negative. This will tell __cxa_end_catch that 863 // exception was rethrown and exception object should not be destroyed 864 // when handler count become zero 865 ex->handlerCount = -ex->handlerCount; 866 867 // Continue unwinding the stack with this exception. This should unwind to 868 // the place in the caller where __cxa_end_catch() is called. The caller 869 // will then run cleanup code and bounce the exception back with 870 // _Unwind_Resume(). 871 _Unwind_Reason_Code err = _Unwind_Resume_or_Rethrow(&ex->unwindHeader); 872 report_failure(err, ex); 873 } 874 875 /** 876 * Returns the type_info object corresponding to the filter. 877 */ 878 static std::type_info *get_type_info_entry(_Unwind_Context *context, 879 dwarf_eh_lsda *lsda, 880 int filter) 881 { 882 // Get the address of the record in the table. 883 dw_eh_ptr_t record = lsda->type_table - 884 dwarf_size_of_fixed_size_field(lsda->type_table_encoding)*filter; 885 //record -= 4; 886 dw_eh_ptr_t start = record; 887 // Read the value, but it's probably an indirect reference... 888 int64_t offset = read_value(lsda->type_table_encoding, &record); 889 890 // (If the entry is 0, don't try to dereference it. That would be bad.) 891 if (offset == 0) { return 0; } 892 893 // ...so we need to resolve it 894 return reinterpret_cast<std::type_info*>(resolve_indirect_value(context, 895 lsda->type_table_encoding, offset, start)); 896 } 897 898 899 900 /** 901 * Checks the type signature found in a handler against the type of the thrown 902 * object. If ex is 0 then it is assumed to be a foreign exception and only 903 * matches cleanups. 904 */ 905 static bool check_type_signature(__cxa_exception *ex, 906 const std::type_info *type, 907 void *&adjustedPtr) 908 { 909 void *exception_ptr = static_cast<void*>(ex+1); 910 const std::type_info *ex_type = ex ? ex->exceptionType : 0; 911 912 bool is_ptr = ex ? ex_type->__is_pointer_p() : false; 913 if (is_ptr) 914 { 915 exception_ptr = *static_cast<void**>(exception_ptr); 916 } 917 // Always match a catchall, even with a foreign exception 918 // 919 // Note: A 0 here is a catchall, not a cleanup, so we return true to 920 // indicate that we found a catch. 921 if (0 == type) 922 { 923 if (ex) 924 { 925 adjustedPtr = exception_ptr; 926 } 927 return true; 928 } 929 930 if (0 == ex) { return false; } 931 932 // If the types are the same, no casting is needed. 933 if (*type == *ex_type) 934 { 935 adjustedPtr = exception_ptr; 936 return true; 937 } 938 939 940 if (type->__do_catch(ex_type, &exception_ptr, 1)) 941 { 942 adjustedPtr = exception_ptr; 943 return true; 944 } 945 946 return false; 947 } 948 /** 949 * Checks whether the exception matches the type specifiers in this action 950 * record. If the exception only matches cleanups, then this returns false. 951 * If it matches a catch (including a catchall) then it returns true. 952 * 953 * The selector argument is used to return the selector that is passed in the 954 * second exception register when installing the context. 955 */ 956 static handler_type check_action_record(_Unwind_Context *context, 957 dwarf_eh_lsda *lsda, 958 dw_eh_ptr_t action_record, 959 __cxa_exception *ex, 960 unsigned long *selector, 961 void *&adjustedPtr) 962 { 963 if (!action_record) { return handler_cleanup; } 964 handler_type found = handler_none; 965 while (action_record) 966 { 967 int filter = read_sleb128(&action_record); 968 dw_eh_ptr_t action_record_offset_base = action_record; 969 int displacement = read_sleb128(&action_record); 970 action_record = displacement ? 971 action_record_offset_base + displacement : 0; 972 // We only check handler types for C++ exceptions - foreign exceptions 973 // are only allowed for cleanups and catchalls. 974 if (filter > 0) 975 { 976 std::type_info *handler_type = get_type_info_entry(context, lsda, filter); 977 if (check_type_signature(ex, handler_type, adjustedPtr)) 978 { 979 *selector = filter; 980 return handler_catch; 981 } 982 } 983 else if (filter < 0 && 0 != ex) 984 { 985 bool matched = false; 986 *selector = filter; 987 #if defined(__arm__) && !defined(__ARM_DWARF_EH__) 988 filter++; 989 std::type_info *handler_type = get_type_info_entry(context, lsda, filter--); 990 while (handler_type) 991 { 992 if (check_type_signature(ex, handler_type, adjustedPtr)) 993 { 994 matched = true; 995 break; 996 } 997 handler_type = get_type_info_entry(context, lsda, filter--); 998 } 999 #else 1000 unsigned char *type_index = reinterpret_cast<unsigned char*>(lsda->type_table) - filter - 1; 1001 while (*type_index) 1002 { 1003 std::type_info *handler_type = get_type_info_entry(context, lsda, *(type_index++)); 1004 // If the exception spec matches a permitted throw type for 1005 // this function, don't report a handler - we are allowed to 1006 // propagate this exception out. 1007 if (check_type_signature(ex, handler_type, adjustedPtr)) 1008 { 1009 matched = true; 1010 break; 1011 } 1012 } 1013 #endif 1014 if (matched) { continue; } 1015 // If we don't find an allowed exception spec, we need to install 1016 // the context for this action. The landing pad will then call the 1017 // unexpected exception function. Treat this as a catch 1018 return handler_catch; 1019 } 1020 else if (filter == 0) 1021 { 1022 *selector = filter; 1023 found = handler_cleanup; 1024 } 1025 } 1026 return found; 1027 } 1028 1029 static void pushCleanupException(_Unwind_Exception *exceptionObject, 1030 __cxa_exception *ex) 1031 { 1032 #if defined(__arm__) && !defined(__ARM_DWARF_EH__) 1033 __cxa_thread_info *info = thread_info_fast(); 1034 if (ex) 1035 { 1036 ex->cleanupCount++; 1037 if (ex->cleanupCount > 1) 1038 { 1039 assert(exceptionObject == info->currentCleanup); 1040 return; 1041 } 1042 ex->nextCleanup = info->currentCleanup; 1043 } 1044 info->currentCleanup = exceptionObject; 1045 #endif 1046 } 1047 1048 /** 1049 * The exception personality function. This is referenced in the unwinding 1050 * DWARF metadata and is called by the unwind library for each C++ stack frame 1051 * containing catch or cleanup code. 1052 */ 1053 extern "C" 1054 BEGIN_PERSONALITY_FUNCTION(__gxx_personality_v0) 1055 // This personality function is for version 1 of the ABI. If you use it 1056 // with a future version of the ABI, it won't know what to do, so it 1057 // reports a fatal error and give up before it breaks anything. 1058 if (1 != version) 1059 { 1060 return _URC_FATAL_PHASE1_ERROR; 1061 } 1062 __cxa_exception *ex = 0; 1063 __cxa_exception *realEx = 0; 1064 1065 // If this exception is throw by something else then we can't make any 1066 // assumptions about its layout beyond the fields declared in 1067 // _Unwind_Exception. 1068 bool foreignException = !isCXXException(exceptionClass); 1069 1070 // If this isn't a foreign exception, then we have a C++ exception structure 1071 if (!foreignException) 1072 { 1073 ex = exceptionFromPointer(exceptionObject); 1074 realEx = realExceptionFromException(ex); 1075 } 1076 1077 #if defined(__arm__) && !defined(__ARM_DWARF_EH__) 1078 unsigned char *lsda_addr = 1079 static_cast<unsigned char*>(_Unwind_GetLanguageSpecificData(context)); 1080 #else 1081 unsigned char *lsda_addr = 1082 reinterpret_cast<unsigned char*>(static_cast<uintptr_t>(_Unwind_GetLanguageSpecificData(context))); 1083 #endif 1084 1085 // No LSDA implies no landing pads - try the next frame 1086 if (0 == lsda_addr) { return continueUnwinding(exceptionObject, context); } 1087 1088 // These two variables define how the exception will be handled. 1089 dwarf_eh_action action = {0}; 1090 unsigned long selector = 0; 1091 1092 // During the search phase, we do a complete lookup. If we return 1093 // _URC_HANDLER_FOUND, then the phase 2 unwind will call this function with 1094 // a _UA_HANDLER_FRAME action, telling us to install the handler frame. If 1095 // we return _URC_CONTINUE_UNWIND, we may be called again later with a 1096 // _UA_CLEANUP_PHASE action for this frame. 1097 // 1098 // The point of the two-stage unwind allows us to entirely avoid any stack 1099 // unwinding if there is no handler. If there are just cleanups found, 1100 // then we can just panic call an abort function. 1101 // 1102 // Matching a handler is much more expensive than matching a cleanup, 1103 // because we don't need to bother doing type comparisons (or looking at 1104 // the type table at all) for a cleanup. This means that there is no need 1105 // to cache the result of finding a cleanup, because it's (quite) quick to 1106 // look it up again from the action table. 1107 if (actions & _UA_SEARCH_PHASE) 1108 { 1109 struct dwarf_eh_lsda lsda = parse_lsda(context, lsda_addr); 1110 1111 if (!dwarf_eh_find_callsite(context, &lsda, &action)) 1112 { 1113 // EH range not found. This happens if exception is thrown and not 1114 // caught inside a cleanup (destructor). We should call 1115 // terminate() in this case. The catchTemp (landing pad) field of 1116 // exception object will contain null when personality function is 1117 // called with _UA_HANDLER_FRAME action for phase 2 unwinding. 1118 return _URC_HANDLER_FOUND; 1119 } 1120 1121 handler_type found_handler = check_action_record(context, &lsda, 1122 action.action_record, realEx, &selector, ex->adjustedPtr); 1123 // If there's no action record, we've only found a cleanup, so keep 1124 // searching for something real 1125 if (found_handler == handler_catch) 1126 { 1127 // Cache the results for the phase 2 unwind, if we found a handler 1128 // and this is not a foreign exception. 1129 if (ex) 1130 { 1131 saveLandingPad(context, exceptionObject, ex, selector, action.landing_pad); 1132 ex->languageSpecificData = reinterpret_cast<const char*>(lsda_addr); 1133 ex->actionRecord = reinterpret_cast<const char*>(action.action_record); 1134 // ex->adjustedPtr is set when finding the action record. 1135 } 1136 return _URC_HANDLER_FOUND; 1137 } 1138 return continueUnwinding(exceptionObject, context); 1139 } 1140 1141 1142 // If this is a foreign exception, we didn't have anywhere to cache the 1143 // lookup stuff, so we need to do it again. If this is either a forced 1144 // unwind, a foreign exception, or a cleanup, then we just install the 1145 // context for a cleanup. 1146 if (!(actions & _UA_HANDLER_FRAME)) 1147 { 1148 // cleanup 1149 struct dwarf_eh_lsda lsda = parse_lsda(context, lsda_addr); 1150 dwarf_eh_find_callsite(context, &lsda, &action); 1151 if (0 == action.landing_pad) { return continueUnwinding(exceptionObject, context); } 1152 handler_type found_handler = check_action_record(context, &lsda, 1153 action.action_record, realEx, &selector, ex->adjustedPtr); 1154 // Ignore handlers this time. 1155 if (found_handler != handler_cleanup) { return continueUnwinding(exceptionObject, context); } 1156 pushCleanupException(exceptionObject, ex); 1157 } 1158 else if (foreignException) 1159 { 1160 struct dwarf_eh_lsda lsda = parse_lsda(context, lsda_addr); 1161 dwarf_eh_find_callsite(context, &lsda, &action); 1162 check_action_record(context, &lsda, action.action_record, realEx, 1163 &selector, ex->adjustedPtr); 1164 } 1165 else if (ex->catchTemp == 0) 1166 { 1167 // Uncaught exception in cleanup, calling terminate 1168 std::terminate(); 1169 } 1170 else 1171 { 1172 // Restore the saved info if we saved some last time. 1173 loadLandingPad(context, exceptionObject, ex, &selector, &action.landing_pad); 1174 ex->catchTemp = 0; 1175 ex->handlerSwitchValue = 0; 1176 } 1177 1178 1179 _Unwind_SetIP(context, reinterpret_cast<unsigned long>(action.landing_pad)); 1180 _Unwind_SetGR(context, __builtin_eh_return_data_regno(0), 1181 reinterpret_cast<unsigned long>(exceptionObject)); 1182 _Unwind_SetGR(context, __builtin_eh_return_data_regno(1), selector); 1183 1184 return _URC_INSTALL_CONTEXT; 1185 } 1186 1187 /** 1188 * ABI function called when entering a catch statement. The argument is the 1189 * pointer passed out of the personality function. This is always the start of 1190 * the _Unwind_Exception object. The return value for this function is the 1191 * pointer to the caught exception, which is either the adjusted pointer (for 1192 * C++ exceptions) of the unadjusted pointer (for foreign exceptions). 1193 */ 1194 #if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 4) 1195 extern "C" void *__cxa_begin_catch(void *e) throw() 1196 #else 1197 extern "C" void *__cxa_begin_catch(void *e) 1198 #endif 1199 { 1200 // We can't call the fast version here, because if the first exception that 1201 // we see is a foreign exception then we won't have called it yet. 1202 __cxa_thread_info *ti = thread_info(); 1203 __cxa_eh_globals *globals = &ti->globals; 1204 globals->uncaughtExceptions--; 1205 _Unwind_Exception *exceptionObject = static_cast<_Unwind_Exception*>(e); 1206 1207 if (isCXXException(exceptionObject->exception_class)) 1208 { 1209 __cxa_exception *ex = exceptionFromPointer(exceptionObject); 1210 1211 if (ex->handlerCount == 0) 1212 { 1213 // Add this to the front of the list of exceptions being handled 1214 // and increment its handler count so that it won't be deleted 1215 // prematurely. 1216 ex->nextException = globals->caughtExceptions; 1217 globals->caughtExceptions = ex; 1218 } 1219 1220 if (ex->handlerCount < 0) 1221 { 1222 // Rethrown exception is catched before end of catch block. 1223 // Clear the rethrow flag (make value positive) - we are allowed 1224 // to delete this exception at the end of the catch block, as long 1225 // as it isn't thrown again later. 1226 1227 // Code pattern: 1228 // 1229 // try { 1230 // throw x; 1231 // } 1232 // catch() { 1233 // try { 1234 // throw; 1235 // } 1236 // catch() { 1237 // __cxa_begin_catch() <- we are here 1238 // } 1239 // } 1240 ex->handlerCount = -ex->handlerCount + 1; 1241 } 1242 else 1243 { 1244 ex->handlerCount++; 1245 } 1246 ti->foreign_exception_state = __cxa_thread_info::none; 1247 1248 return ex->adjustedPtr; 1249 } 1250 else 1251 { 1252 // If this is a foreign exception, then we need to be able to 1253 // store it. We can't chain foreign exceptions, so we give up 1254 // if there are already some outstanding ones. 1255 if (globals->caughtExceptions != 0) 1256 { 1257 std::terminate(); 1258 } 1259 globals->caughtExceptions = reinterpret_cast<__cxa_exception*>(exceptionObject); 1260 ti->foreign_exception_state = __cxa_thread_info::caught; 1261 } 1262 // exceptionObject is the pointer to the _Unwind_Exception within the 1263 // __cxa_exception. The throw object is after this 1264 return (reinterpret_cast<char*>(exceptionObject) + sizeof(_Unwind_Exception)); 1265 } 1266 1267 1268 1269 /** 1270 * ABI function called when exiting a catch block. This will free the current 1271 * exception if it is no longer referenced in other catch blocks. 1272 */ 1273 extern "C" void __cxa_end_catch() 1274 { 1275 // We can call the fast version here because the slow version is called in 1276 // __cxa_throw(), which must have been called before we end a catch block 1277 __cxa_thread_info *ti = thread_info_fast(); 1278 __cxa_eh_globals *globals = &ti->globals; 1279 __cxa_exception *ex = globals->caughtExceptions; 1280 1281 assert(0 != ex && "Ending catch when no exception is on the stack!"); 1282 1283 if (ti->foreign_exception_state != __cxa_thread_info::none) 1284 { 1285 globals->caughtExceptions = 0; 1286 if (ti->foreign_exception_state != __cxa_thread_info::rethrown) 1287 { 1288 _Unwind_Exception *e = reinterpret_cast<_Unwind_Exception*>(ti->globals.caughtExceptions); 1289 e->exception_cleanup(_URC_FOREIGN_EXCEPTION_CAUGHT, e); 1290 } 1291 ti->foreign_exception_state = __cxa_thread_info::none; 1292 return; 1293 } 1294 1295 bool deleteException = true; 1296 1297 if (ex->handlerCount < 0) 1298 { 1299 // exception was rethrown. Exception should not be deleted even if 1300 // handlerCount become zero. 1301 // Code pattern: 1302 // try { 1303 // throw x; 1304 // } 1305 // catch() { 1306 // { 1307 // throw; 1308 // } 1309 // cleanup { 1310 // __cxa_end_catch(); <- we are here 1311 // } 1312 // } 1313 // 1314 1315 ex->handlerCount++; 1316 deleteException = false; 1317 } 1318 else 1319 { 1320 ex->handlerCount--; 1321 } 1322 1323 if (ex->handlerCount == 0) 1324 { 1325 globals->caughtExceptions = ex->nextException; 1326 if (deleteException) 1327 { 1328 releaseException(ex); 1329 } 1330 } 1331 } 1332 1333 /** 1334 * ABI function. Returns the type of the current exception. 1335 */ 1336 extern "C" std::type_info *__cxa_current_exception_type() 1337 { 1338 __cxa_eh_globals *globals = __cxa_get_globals(); 1339 __cxa_exception *ex = globals->caughtExceptions; 1340 return ex ? ex->exceptionType : 0; 1341 } 1342 1343 /** 1344 * ABI function, called when an exception specification is violated. 1345 * 1346 * This function does not return. 1347 */ 1348 extern "C" void __cxa_call_unexpected(void*exception) 1349 { 1350 _Unwind_Exception *exceptionObject = static_cast<_Unwind_Exception*>(exception); 1351 if (exceptionObject->exception_class == exception_class) 1352 { 1353 __cxa_exception *ex = exceptionFromPointer(exceptionObject); 1354 if (ex->unexpectedHandler) 1355 { 1356 ex->unexpectedHandler(); 1357 // Should not be reached. 1358 abort(); 1359 } 1360 } 1361 std::unexpected(); 1362 // Should not be reached. 1363 abort(); 1364 } 1365 1366 /** 1367 * ABI function, returns the adjusted pointer to the exception object. 1368 */ 1369 extern "C" void *__cxa_get_exception_ptr(void *exceptionObject) 1370 { 1371 return exceptionFromPointer(exceptionObject)->adjustedPtr; 1372 } 1373 1374 /** 1375 * As an extension, we provide the ability for the unexpected and terminate 1376 * handlers to be thread-local. We default to the standards-compliant 1377 * behaviour where they are global. 1378 */ 1379 static bool thread_local_handlers = false; 1380 1381 1382 namespace pathscale 1383 { 1384 /** 1385 * Sets whether unexpected and terminate handlers should be thread-local. 1386 */ 1387 void set_use_thread_local_handlers(bool flag) throw() 1388 { 1389 thread_local_handlers = flag; 1390 } 1391 /** 1392 * Sets a thread-local unexpected handler. 1393 */ 1394 unexpected_handler set_unexpected(unexpected_handler f) throw() 1395 { 1396 static __cxa_thread_info *info = thread_info(); 1397 unexpected_handler old = info->unexpectedHandler; 1398 info->unexpectedHandler = f; 1399 return old; 1400 } 1401 /** 1402 * Sets a thread-local terminate handler. 1403 */ 1404 terminate_handler set_terminate(terminate_handler f) throw() 1405 { 1406 static __cxa_thread_info *info = thread_info(); 1407 terminate_handler old = info->terminateHandler; 1408 info->terminateHandler = f; 1409 return old; 1410 } 1411 } 1412 1413 namespace std 1414 { 1415 /** 1416 * Sets the function that will be called when an exception specification is 1417 * violated. 1418 */ 1419 unexpected_handler set_unexpected(unexpected_handler f) throw() 1420 { 1421 if (thread_local_handlers) { return pathscale::set_unexpected(f); } 1422 1423 return ATOMIC_SWAP(&unexpectedHandler, f); 1424 } 1425 /** 1426 * Sets the function that is called to terminate the program. 1427 */ 1428 terminate_handler set_terminate(terminate_handler f) throw() 1429 { 1430 if (thread_local_handlers) { return pathscale::set_terminate(f); } 1431 1432 return ATOMIC_SWAP(&terminateHandler, f); 1433 } 1434 /** 1435 * Terminates the program, calling a custom terminate implementation if 1436 * required. 1437 */ 1438 void terminate() 1439 { 1440 static __cxa_thread_info *info = thread_info(); 1441 if (0 != info && 0 != info->terminateHandler) 1442 { 1443 info->terminateHandler(); 1444 // Should not be reached - a terminate handler is not expected to 1445 // return. 1446 abort(); 1447 } 1448 terminateHandler(); 1449 } 1450 /** 1451 * Called when an unexpected exception is encountered (i.e. an exception 1452 * violates an exception specification). This calls abort() unless a 1453 * custom handler has been set.. 1454 */ 1455 void unexpected() 1456 { 1457 static __cxa_thread_info *info = thread_info(); 1458 if (0 != info && 0 != info->unexpectedHandler) 1459 { 1460 info->unexpectedHandler(); 1461 // Should not be reached - a terminate handler is not expected to 1462 // return. 1463 abort(); 1464 } 1465 unexpectedHandler(); 1466 } 1467 /** 1468 * Returns whether there are any exceptions currently being thrown that 1469 * have not been caught. This can occur inside a nested catch statement. 1470 */ 1471 bool uncaught_exception() throw() 1472 { 1473 __cxa_thread_info *info = thread_info(); 1474 return info->globals.uncaughtExceptions != 0; 1475 } 1476 /** 1477 * Returns the current unexpected handler. 1478 */ 1479 unexpected_handler get_unexpected() throw() 1480 { 1481 __cxa_thread_info *info = thread_info(); 1482 if (info->unexpectedHandler) 1483 { 1484 return info->unexpectedHandler; 1485 } 1486 return ATOMIC_LOAD(&unexpectedHandler); 1487 } 1488 /** 1489 * Returns the current terminate handler. 1490 */ 1491 terminate_handler get_terminate() throw() 1492 { 1493 __cxa_thread_info *info = thread_info(); 1494 if (info->terminateHandler) 1495 { 1496 return info->terminateHandler; 1497 } 1498 return ATOMIC_LOAD(&terminateHandler); 1499 } 1500 } 1501 #if defined(__arm__) && !defined(__ARM_DWARF_EH__) 1502 extern "C" _Unwind_Exception *__cxa_get_cleanup(void) 1503 { 1504 __cxa_thread_info *info = thread_info_fast(); 1505 _Unwind_Exception *exceptionObject = info->currentCleanup; 1506 if (isCXXException(exceptionObject->exception_class)) 1507 { 1508 __cxa_exception *ex = exceptionFromPointer(exceptionObject); 1509 ex->cleanupCount--; 1510 if (ex->cleanupCount == 0) 1511 { 1512 info->currentCleanup = ex->nextCleanup; 1513 ex->nextCleanup = 0; 1514 } 1515 } 1516 else 1517 { 1518 info->currentCleanup = 0; 1519 } 1520 return exceptionObject; 1521 } 1522 1523 asm ( 1524 ".pushsection .text.__cxa_end_cleanup \n" 1525 ".global __cxa_end_cleanup \n" 1526 ".type __cxa_end_cleanup, \"function\" \n" 1527 "__cxa_end_cleanup: \n" 1528 " push {r1, r2, r3, r4} \n" 1529 " bl __cxa_get_cleanup \n" 1530 " push {r1, r2, r3, r4} \n" 1531 " b _Unwind_Resume \n" 1532 " bl abort \n" 1533 ".popsection \n" 1534 ); 1535 #endif 1536