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 
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
782