re PR libstdc++/49818 (libsupc++ does not export __cxa_get_globals or related functions)
[gcc.git] / libstdc++-v3 / libsupc++ / eh_personality.cc
1 // -*- C++ -*- The GNU C++ exception personality routine.
2 // Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010,
3 // 2011
4 // Free Software Foundation, Inc.
5 //
6 // This file is part of GCC.
7 //
8 // GCC is free software; you can redistribute it and/or modify
9 // it under the terms of the GNU General Public License as published by
10 // the Free Software Foundation; either version 3, or (at your option)
11 // any later version.
12 //
13 // GCC is distributed in the hope that it will be useful,
14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 // GNU General Public License for more details.
17 //
18 // Under Section 7 of GPL version 3, you are granted additional
19 // permissions described in the GCC Runtime Library Exception, version
20 // 3.1, as published by the Free Software Foundation.
21
22 // You should have received a copy of the GNU General Public License and
23 // a copy of the GCC Runtime Library Exception along with this program;
24 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
25 // <http://www.gnu.org/licenses/>.
26
27 #include <bits/c++config.h>
28 #include <cstdlib>
29 #include <bits/exception_defines.h>
30 #include <cxxabi.h>
31 #include "unwind-cxx.h"
32
33
34 using namespace __cxxabiv1;
35
36 #include "unwind-pe.h"
37
38 \f
39 struct lsda_header_info
40 {
41 _Unwind_Ptr Start;
42 _Unwind_Ptr LPStart;
43 _Unwind_Ptr ttype_base;
44 const unsigned char *TType;
45 const unsigned char *action_table;
46 unsigned char ttype_encoding;
47 unsigned char call_site_encoding;
48 };
49
50 static const unsigned char *
51 parse_lsda_header (_Unwind_Context *context, const unsigned char *p,
52 lsda_header_info *info)
53 {
54 _uleb128_t tmp;
55 unsigned char lpstart_encoding;
56
57 info->Start = (context ? _Unwind_GetRegionStart (context) : 0);
58
59 // Find @LPStart, the base to which landing pad offsets are relative.
60 lpstart_encoding = *p++;
61 if (lpstart_encoding != DW_EH_PE_omit)
62 p = read_encoded_value (context, lpstart_encoding, p, &info->LPStart);
63 else
64 info->LPStart = info->Start;
65
66 // Find @TType, the base of the handler and exception spec type data.
67 info->ttype_encoding = *p++;
68 if (info->ttype_encoding != DW_EH_PE_omit)
69 {
70 #if _GLIBCXX_OVERRIDE_TTYPE_ENCODING
71 /* Older ARM EABI toolchains set this value incorrectly, so use a
72 hardcoded OS-specific format. */
73 info->ttype_encoding = _GLIBCXX_OVERRIDE_TTYPE_ENCODING;
74 #endif
75 p = read_uleb128 (p, &tmp);
76 info->TType = p + tmp;
77 }
78 else
79 info->TType = 0;
80
81 // The encoding and length of the call-site table; the action table
82 // immediately follows.
83 info->call_site_encoding = *p++;
84 p = read_uleb128 (p, &tmp);
85 info->action_table = p + tmp;
86
87 return p;
88 }
89
90 // Return an element from a type table.
91
92 static const std::type_info *
93 get_ttype_entry (lsda_header_info *info, _uleb128_t i)
94 {
95 _Unwind_Ptr ptr;
96
97 i *= size_of_encoded_value (info->ttype_encoding);
98 read_encoded_value_with_base (info->ttype_encoding, info->ttype_base,
99 info->TType - i, &ptr);
100
101 return reinterpret_cast<const std::type_info *>(ptr);
102 }
103
104 #ifdef __ARM_EABI_UNWINDER__
105
106 // The ABI provides a routine for matching exception object types.
107 typedef _Unwind_Control_Block _throw_typet;
108 #define get_adjusted_ptr(catch_type, throw_type, thrown_ptr_p) \
109 (__cxa_type_match (throw_type, catch_type, false, thrown_ptr_p) \
110 != ctm_failed)
111
112 // Return true if THROW_TYPE matches one if the filter types.
113
114 static bool
115 check_exception_spec(lsda_header_info* info, _throw_typet* throw_type,
116 void* thrown_ptr, _sleb128_t filter_value)
117 {
118 const _uleb128_t* e = ((const _uleb128_t*) info->TType)
119 - filter_value - 1;
120
121 while (1)
122 {
123 const std::type_info* catch_type;
124 _uleb128_t tmp;
125
126 tmp = *e;
127
128 // Zero signals the end of the list. If we've not found
129 // a match by now, then we've failed the specification.
130 if (tmp == 0)
131 return false;
132
133 tmp = _Unwind_decode_typeinfo_ptr(info->ttype_base, (_Unwind_Word) e);
134
135 // Match a ttype entry.
136 catch_type = reinterpret_cast<const std::type_info*>(tmp);
137
138 // ??? There is currently no way to ask the RTTI code about the
139 // relationship between two types without reference to a specific
140 // object. There should be; then we wouldn't need to mess with
141 // thrown_ptr here.
142 if (get_adjusted_ptr(catch_type, throw_type, &thrown_ptr))
143 return true;
144
145 // Advance to the next entry.
146 e++;
147 }
148 }
149
150
151 // Save stage1 handler information in the exception object
152
153 static inline void
154 save_caught_exception(struct _Unwind_Exception* ue_header,
155 struct _Unwind_Context* context,
156 void* thrown_ptr,
157 int handler_switch_value,
158 const unsigned char* language_specific_data,
159 _Unwind_Ptr landing_pad,
160 const unsigned char* action_record
161 __attribute__((__unused__)))
162 {
163 ue_header->barrier_cache.sp = _Unwind_GetGR(context, UNWIND_STACK_REG);
164 ue_header->barrier_cache.bitpattern[0] = (_uw) thrown_ptr;
165 ue_header->barrier_cache.bitpattern[1]
166 = (_uw) handler_switch_value;
167 ue_header->barrier_cache.bitpattern[2]
168 = (_uw) language_specific_data;
169 ue_header->barrier_cache.bitpattern[3] = (_uw) landing_pad;
170 }
171
172
173 // Restore the catch handler data saved during phase1.
174
175 static inline void
176 restore_caught_exception(struct _Unwind_Exception* ue_header,
177 int& handler_switch_value,
178 const unsigned char*& language_specific_data,
179 _Unwind_Ptr& landing_pad)
180 {
181 handler_switch_value = (int) ue_header->barrier_cache.bitpattern[1];
182 language_specific_data =
183 (const unsigned char*) ue_header->barrier_cache.bitpattern[2];
184 landing_pad = (_Unwind_Ptr) ue_header->barrier_cache.bitpattern[3];
185 }
186
187 #define CONTINUE_UNWINDING \
188 do \
189 { \
190 if (__gnu_unwind_frame(ue_header, context) != _URC_OK) \
191 return _URC_FAILURE; \
192 return _URC_CONTINUE_UNWIND; \
193 } \
194 while (0)
195
196 // Return true if the filter spec is empty, ie throw().
197
198 static bool
199 empty_exception_spec (lsda_header_info *info, _Unwind_Sword filter_value)
200 {
201 const _Unwind_Word* e = ((const _Unwind_Word*) info->TType)
202 - filter_value - 1;
203
204 return *e == 0;
205 }
206
207 #else
208 typedef const std::type_info _throw_typet;
209
210
211 // Given the thrown type THROW_TYPE, pointer to a variable containing a
212 // pointer to the exception object THROWN_PTR_P and a type CATCH_TYPE to
213 // compare against, return whether or not there is a match and if so,
214 // update *THROWN_PTR_P.
215
216 static bool
217 get_adjusted_ptr (const std::type_info *catch_type,
218 const std::type_info *throw_type,
219 void **thrown_ptr_p)
220 {
221 void *thrown_ptr = *thrown_ptr_p;
222
223 // Pointer types need to adjust the actual pointer, not
224 // the pointer to pointer that is the exception object.
225 // This also has the effect of passing pointer types
226 // "by value" through the __cxa_begin_catch return value.
227 if (throw_type->__is_pointer_p ())
228 thrown_ptr = *(void **) thrown_ptr;
229
230 if (catch_type->__do_catch (throw_type, &thrown_ptr, 1))
231 {
232 *thrown_ptr_p = thrown_ptr;
233 return true;
234 }
235
236 return false;
237 }
238
239 // Return true if THROW_TYPE matches one if the filter types.
240
241 static bool
242 check_exception_spec(lsda_header_info* info, _throw_typet* throw_type,
243 void* thrown_ptr, _sleb128_t filter_value)
244 {
245 const unsigned char *e = info->TType - filter_value - 1;
246
247 while (1)
248 {
249 const std::type_info *catch_type;
250 _uleb128_t tmp;
251
252 e = read_uleb128 (e, &tmp);
253
254 // Zero signals the end of the list. If we've not found
255 // a match by now, then we've failed the specification.
256 if (tmp == 0)
257 return false;
258
259 // Match a ttype entry.
260 catch_type = get_ttype_entry (info, tmp);
261
262 // ??? There is currently no way to ask the RTTI code about the
263 // relationship between two types without reference to a specific
264 // object. There should be; then we wouldn't need to mess with
265 // thrown_ptr here.
266 if (get_adjusted_ptr (catch_type, throw_type, &thrown_ptr))
267 return true;
268 }
269 }
270
271
272 // Save stage1 handler information in the exception object
273
274 static inline void
275 save_caught_exception(struct _Unwind_Exception* ue_header,
276 struct _Unwind_Context* context
277 __attribute__((__unused__)),
278 void* thrown_ptr,
279 int handler_switch_value,
280 const unsigned char* language_specific_data,
281 _Unwind_Ptr landing_pad __attribute__((__unused__)),
282 const unsigned char* action_record)
283 {
284 __cxa_exception* xh = __get_exception_header_from_ue(ue_header);
285
286 xh->handlerSwitchValue = handler_switch_value;
287 xh->actionRecord = action_record;
288 xh->languageSpecificData = language_specific_data;
289 xh->adjustedPtr = thrown_ptr;
290
291 // ??? Completely unknown what this field is supposed to be for.
292 // ??? Need to cache TType encoding base for call_unexpected.
293 xh->catchTemp = landing_pad;
294 }
295
296
297 // Restore the catch handler information saved during phase1.
298
299 static inline void
300 restore_caught_exception(struct _Unwind_Exception* ue_header,
301 int& handler_switch_value,
302 const unsigned char*& language_specific_data,
303 _Unwind_Ptr& landing_pad)
304 {
305 __cxa_exception* xh = __get_exception_header_from_ue(ue_header);
306 handler_switch_value = xh->handlerSwitchValue;
307 language_specific_data = xh->languageSpecificData;
308 landing_pad = (_Unwind_Ptr) xh->catchTemp;
309 }
310
311 #define CONTINUE_UNWINDING return _URC_CONTINUE_UNWIND
312
313 // Return true if the filter spec is empty, ie throw().
314
315 static bool
316 empty_exception_spec (lsda_header_info *info, _Unwind_Sword filter_value)
317 {
318 const unsigned char *e = info->TType - filter_value - 1;
319 _uleb128_t tmp;
320
321 e = read_uleb128 (e, &tmp);
322 return tmp == 0;
323 }
324
325 #endif // !__ARM_EABI_UNWINDER__
326
327 namespace __cxxabiv1
328 {
329
330 // Using a different personality function name causes link failures
331 // when trying to mix code using different exception handling models.
332 #ifdef _GLIBCXX_SJLJ_EXCEPTIONS
333 #define PERSONALITY_FUNCTION __gxx_personality_sj0
334 #define __builtin_eh_return_data_regno(x) x
335 #else
336 #define PERSONALITY_FUNCTION __gxx_personality_v0
337 #endif
338
339 extern "C" _Unwind_Reason_Code
340 #ifdef __ARM_EABI_UNWINDER__
341 PERSONALITY_FUNCTION (_Unwind_State state,
342 struct _Unwind_Exception* ue_header,
343 struct _Unwind_Context* context)
344 #else
345 PERSONALITY_FUNCTION (int version,
346 _Unwind_Action actions,
347 _Unwind_Exception_Class exception_class,
348 struct _Unwind_Exception *ue_header,
349 struct _Unwind_Context *context)
350 #endif
351 {
352 enum found_handler_type
353 {
354 found_nothing,
355 found_terminate,
356 found_cleanup,
357 found_handler
358 } found_type;
359
360 lsda_header_info info;
361 const unsigned char *language_specific_data;
362 const unsigned char *action_record;
363 const unsigned char *p;
364 _Unwind_Ptr landing_pad, ip;
365 int handler_switch_value;
366 void* thrown_ptr = 0;
367 bool foreign_exception;
368 int ip_before_insn = 0;
369
370 #ifdef __ARM_EABI_UNWINDER__
371 _Unwind_Action actions;
372
373 switch (state & _US_ACTION_MASK)
374 {
375 case _US_VIRTUAL_UNWIND_FRAME:
376 actions = _UA_SEARCH_PHASE;
377 break;
378
379 case _US_UNWIND_FRAME_STARTING:
380 actions = _UA_CLEANUP_PHASE;
381 if (!(state & _US_FORCE_UNWIND)
382 && ue_header->barrier_cache.sp == _Unwind_GetGR(context,
383 UNWIND_STACK_REG))
384 actions |= _UA_HANDLER_FRAME;
385 break;
386
387 case _US_UNWIND_FRAME_RESUME:
388 CONTINUE_UNWINDING;
389 break;
390
391 default:
392 std::abort();
393 }
394 actions |= state & _US_FORCE_UNWIND;
395
396 // We don't know which runtime we're working with, so can't check this.
397 // However the ABI routines hide this from us, and we don't actually need
398 // to know.
399 foreign_exception = false;
400
401 // The dwarf unwinder assumes the context structure holds things like the
402 // function and LSDA pointers. The ARM implementation caches these in
403 // the exception header (UCB). To avoid rewriting everything we make a
404 // virtual scratch register point at the UCB.
405 ip = (_Unwind_Ptr) ue_header;
406 _Unwind_SetGR(context, UNWIND_POINTER_REG, ip);
407 #else
408 __cxa_exception* xh = __get_exception_header_from_ue(ue_header);
409
410 // Interface version check.
411 if (version != 1)
412 return _URC_FATAL_PHASE1_ERROR;
413 foreign_exception = !__is_gxx_exception_class(exception_class);
414 #endif
415
416 // Shortcut for phase 2 found handler for domestic exception.
417 if (actions == (_UA_CLEANUP_PHASE | _UA_HANDLER_FRAME)
418 && !foreign_exception)
419 {
420 restore_caught_exception(ue_header, handler_switch_value,
421 language_specific_data, landing_pad);
422 found_type = (landing_pad == 0 ? found_terminate : found_handler);
423 goto install_context;
424 }
425
426 language_specific_data = (const unsigned char *)
427 _Unwind_GetLanguageSpecificData (context);
428
429 // If no LSDA, then there are no handlers or cleanups.
430 if (! language_specific_data)
431 CONTINUE_UNWINDING;
432
433 // Parse the LSDA header.
434 p = parse_lsda_header (context, language_specific_data, &info);
435 info.ttype_base = base_of_encoded_value (info.ttype_encoding, context);
436 #ifdef _GLIBCXX_HAVE_GETIPINFO
437 ip = _Unwind_GetIPInfo (context, &ip_before_insn);
438 #else
439 ip = _Unwind_GetIP (context);
440 #endif
441 if (! ip_before_insn)
442 --ip;
443 landing_pad = 0;
444 action_record = 0;
445 handler_switch_value = 0;
446
447 #ifdef _GLIBCXX_SJLJ_EXCEPTIONS
448 // The given "IP" is an index into the call-site table, with two
449 // exceptions -- -1 means no-action, and 0 means terminate. But
450 // since we're using uleb128 values, we've not got random access
451 // to the array.
452 if ((int) ip < 0)
453 return _URC_CONTINUE_UNWIND;
454 else if (ip == 0)
455 {
456 // Fall through to set found_terminate.
457 }
458 else
459 {
460 _uleb128_t cs_lp, cs_action;
461 do
462 {
463 p = read_uleb128 (p, &cs_lp);
464 p = read_uleb128 (p, &cs_action);
465 }
466 while (--ip);
467
468 // Can never have null landing pad for sjlj -- that would have
469 // been indicated by a -1 call site index.
470 landing_pad = cs_lp + 1;
471 if (cs_action)
472 action_record = info.action_table + cs_action - 1;
473 goto found_something;
474 }
475 #else
476 // Search the call-site table for the action associated with this IP.
477 while (p < info.action_table)
478 {
479 _Unwind_Ptr cs_start, cs_len, cs_lp;
480 _uleb128_t cs_action;
481
482 // Note that all call-site encodings are "absolute" displacements.
483 p = read_encoded_value (0, info.call_site_encoding, p, &cs_start);
484 p = read_encoded_value (0, info.call_site_encoding, p, &cs_len);
485 p = read_encoded_value (0, info.call_site_encoding, p, &cs_lp);
486 p = read_uleb128 (p, &cs_action);
487
488 // The table is sorted, so if we've passed the ip, stop.
489 if (ip < info.Start + cs_start)
490 p = info.action_table;
491 else if (ip < info.Start + cs_start + cs_len)
492 {
493 if (cs_lp)
494 landing_pad = info.LPStart + cs_lp;
495 if (cs_action)
496 action_record = info.action_table + cs_action - 1;
497 goto found_something;
498 }
499 }
500 #endif // _GLIBCXX_SJLJ_EXCEPTIONS
501
502 // If ip is not present in the table, call terminate. This is for
503 // a destructor inside a cleanup, or a library routine the compiler
504 // was not expecting to throw.
505 found_type = found_terminate;
506 goto do_something;
507
508 found_something:
509 if (landing_pad == 0)
510 {
511 // If ip is present, and has a null landing pad, there are
512 // no cleanups or handlers to be run.
513 found_type = found_nothing;
514 }
515 else if (action_record == 0)
516 {
517 // If ip is present, has a non-null landing pad, and a null
518 // action table offset, then there are only cleanups present.
519 // Cleanups use a zero switch value, as set above.
520 found_type = found_cleanup;
521 }
522 else
523 {
524 // Otherwise we have a catch handler or exception specification.
525
526 _sleb128_t ar_filter, ar_disp;
527 const std::type_info* catch_type;
528 _throw_typet* throw_type;
529 bool saw_cleanup = false;
530 bool saw_handler = false;
531
532 #ifdef __ARM_EABI_UNWINDER__
533 // ??? How does this work - more importantly, how does it interact with
534 // dependent exceptions?
535 throw_type = ue_header;
536 if (actions & _UA_FORCE_UNWIND)
537 {
538 __GXX_INIT_FORCED_UNWIND_CLASS(ue_header->exception_class);
539 }
540 else if (!foreign_exception)
541 thrown_ptr = __get_object_from_ue (ue_header);
542 #else
543 #ifdef __GXX_RTTI
544 // During forced unwinding, match a magic exception type.
545 if (actions & _UA_FORCE_UNWIND)
546 {
547 throw_type = &typeid(abi::__forced_unwind);
548 }
549 // With a foreign exception class, there's no exception type.
550 // ??? What to do about GNU Java and GNU Ada exceptions?
551 else if (foreign_exception)
552 {
553 throw_type = &typeid(abi::__foreign_exception);
554 }
555 else
556 #endif
557 {
558 thrown_ptr = __get_object_from_ue (ue_header);
559 throw_type = __get_exception_header_from_obj
560 (thrown_ptr)->exceptionType;
561 }
562 #endif
563
564 while (1)
565 {
566 p = action_record;
567 p = read_sleb128 (p, &ar_filter);
568 read_sleb128 (p, &ar_disp);
569
570 if (ar_filter == 0)
571 {
572 // Zero filter values are cleanups.
573 saw_cleanup = true;
574 }
575 else if (ar_filter > 0)
576 {
577 // Positive filter values are handlers.
578 catch_type = get_ttype_entry (&info, ar_filter);
579
580 // Null catch type is a catch-all handler; we can catch foreign
581 // exceptions with this. Otherwise we must match types.
582 if (! catch_type
583 || (throw_type
584 && get_adjusted_ptr (catch_type, throw_type,
585 &thrown_ptr)))
586 {
587 saw_handler = true;
588 break;
589 }
590 }
591 else
592 {
593 // Negative filter values are exception specifications.
594 // ??? How do foreign exceptions fit in? As far as I can
595 // see we can't match because there's no __cxa_exception
596 // object to stuff bits in for __cxa_call_unexpected to use.
597 // Allow them iff the exception spec is non-empty. I.e.
598 // a throw() specification results in __unexpected.
599 if ((throw_type
600 && !(actions & _UA_FORCE_UNWIND)
601 && !foreign_exception)
602 ? ! check_exception_spec (&info, throw_type, thrown_ptr,
603 ar_filter)
604 : empty_exception_spec (&info, ar_filter))
605 {
606 saw_handler = true;
607 break;
608 }
609 }
610
611 if (ar_disp == 0)
612 break;
613 action_record = p + ar_disp;
614 }
615
616 if (saw_handler)
617 {
618 handler_switch_value = ar_filter;
619 found_type = found_handler;
620 }
621 else
622 found_type = (saw_cleanup ? found_cleanup : found_nothing);
623 }
624
625 do_something:
626 if (found_type == found_nothing)
627 CONTINUE_UNWINDING;
628
629 if (actions & _UA_SEARCH_PHASE)
630 {
631 if (found_type == found_cleanup)
632 CONTINUE_UNWINDING;
633
634 // For domestic exceptions, we cache data from phase 1 for phase 2.
635 if (!foreign_exception)
636 {
637 save_caught_exception(ue_header, context, thrown_ptr,
638 handler_switch_value, language_specific_data,
639 landing_pad, action_record);
640 }
641 return _URC_HANDLER_FOUND;
642 }
643
644 install_context:
645
646 // We can't use any of the cxa routines with foreign exceptions,
647 // because they all expect ue_header to be a struct __cxa_exception.
648 // So in that case, call terminate or unexpected directly.
649 if ((actions & _UA_FORCE_UNWIND)
650 || foreign_exception)
651 {
652 if (found_type == found_terminate)
653 std::terminate ();
654 else if (handler_switch_value < 0)
655 {
656 __try
657 { std::unexpected (); }
658 __catch(...)
659 { std::terminate (); }
660 }
661 }
662 else
663 {
664 if (found_type == found_terminate)
665 __cxa_call_terminate(ue_header);
666
667 // Cache the TType base value for __cxa_call_unexpected, as we won't
668 // have an _Unwind_Context then.
669 if (handler_switch_value < 0)
670 {
671 parse_lsda_header (context, language_specific_data, &info);
672 info.ttype_base = base_of_encoded_value (info.ttype_encoding,
673 context);
674
675 #ifdef __ARM_EABI_UNWINDER__
676 const _Unwind_Word* e;
677 _Unwind_Word n;
678
679 e = ((const _Unwind_Word*) info.TType) - handler_switch_value - 1;
680 // Count the number of rtti objects.
681 n = 0;
682 while (e[n] != 0)
683 n++;
684
685 // Count.
686 ue_header->barrier_cache.bitpattern[1] = n;
687 // Base
688 ue_header->barrier_cache.bitpattern[2] = info.ttype_base;
689 // Stride.
690 ue_header->barrier_cache.bitpattern[3] = 4;
691 // List head.
692 ue_header->barrier_cache.bitpattern[4] = (_Unwind_Word) e;
693 #else
694 xh->catchTemp = base_of_encoded_value (info.ttype_encoding, context);
695 #endif
696 }
697 }
698
699 /* For targets with pointers smaller than the word size, we must extend the
700 pointer, and this extension is target dependent. */
701 _Unwind_SetGR (context, __builtin_eh_return_data_regno (0),
702 __builtin_extend_pointer (ue_header));
703 _Unwind_SetGR (context, __builtin_eh_return_data_regno (1),
704 handler_switch_value);
705 _Unwind_SetIP (context, landing_pad);
706 #ifdef __ARM_EABI_UNWINDER__
707 if (found_type == found_cleanup)
708 __cxa_begin_cleanup(ue_header);
709 #endif
710 return _URC_INSTALL_CONTEXT;
711 }
712
713 /* The ARM EABI implementation of __cxa_call_unexpected is in a
714 different file so that the personality routine (PR) can be used
715 standalone. The generic routine shared datastructures with the PR
716 so it is most convenient to implement it here. */
717 #ifndef __ARM_EABI_UNWINDER__
718 extern "C" void
719 __cxa_call_unexpected (void *exc_obj_in)
720 {
721 _Unwind_Exception *exc_obj
722 = reinterpret_cast <_Unwind_Exception *>(exc_obj_in);
723
724 __cxa_begin_catch (exc_obj);
725
726 // This function is a handler for our exception argument. If we exit
727 // by throwing a different exception, we'll need the original cleaned up.
728 struct end_catch_protect
729 {
730 end_catch_protect() { }
731 ~end_catch_protect() { __cxa_end_catch(); }
732 } end_catch_protect_obj;
733
734 lsda_header_info info;
735 __cxa_exception *xh = __get_exception_header_from_ue (exc_obj);
736 const unsigned char *xh_lsda;
737 _Unwind_Sword xh_switch_value;
738 std::terminate_handler xh_terminate_handler;
739
740 // If the unexpectedHandler rethrows the exception (e.g. to categorize it),
741 // it will clobber data about the current handler. So copy the data out now.
742 xh_lsda = xh->languageSpecificData;
743 xh_switch_value = xh->handlerSwitchValue;
744 xh_terminate_handler = xh->terminateHandler;
745 info.ttype_base = (_Unwind_Ptr) xh->catchTemp;
746
747 __try
748 { __unexpected (xh->unexpectedHandler); }
749 __catch(...)
750 {
751 // Get the exception thrown from unexpected.
752
753 __cxa_eh_globals *globals = __cxa_get_globals_fast ();
754 __cxa_exception *new_xh = globals->caughtExceptions;
755 void *new_ptr = __get_object_from_ambiguous_exception (new_xh);
756
757 // We don't quite have enough stuff cached; re-parse the LSDA.
758 parse_lsda_header (0, xh_lsda, &info);
759
760 // If this new exception meets the exception spec, allow it.
761 if (check_exception_spec (&info, __get_exception_header_from_obj
762 (new_ptr)->exceptionType,
763 new_ptr, xh_switch_value))
764 __throw_exception_again;
765
766 // If the exception spec allows std::bad_exception, throw that.
767 // We don't have a thrown object to compare against, but since
768 // bad_exception doesn't have virtual bases, that's OK; just pass 0.
769 #if defined(__EXCEPTIONS) && defined(__GXX_RTTI)
770 const std::type_info &bad_exc = typeid (std::bad_exception);
771 if (check_exception_spec (&info, &bad_exc, 0, xh_switch_value))
772 throw std::bad_exception();
773 #endif
774
775 // Otherwise, die.
776 __terminate (xh_terminate_handler);
777 }
778 }
779 #endif
780
781 } // namespace __cxxabiv1