1 /****************************************************************************
3 * GNAT COMPILER COMPONENTS *
7 * C Implementation File *
9 * Copyright (C) 1992-2008, Free Software Foundation, Inc. *
11 * GNAT is free software; you can redistribute it and/or modify it under *
12 * terms of the GNU General Public License as published by the Free Soft- *
13 * ware Foundation; either version 2, or (at your option) any later ver- *
14 * sion. GNAT is distributed in the hope that it will be useful, but WITH- *
15 * OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY *
16 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License *
17 * for more details. You should have received a copy of the GNU General *
18 * Public License distributed with GNAT; see file COPYING. If not, write *
19 * to the Free Software Foundation, 51 Franklin Street, Fifth Floor, *
20 * Boston, MA 02110-1301, USA. *
22 * As a special exception, if you link this file with other files to *
23 * produce an executable, this file does not by itself cause the resulting *
24 * executable to be covered by the GNU General Public License. This except- *
25 * ion does not however invalidate any other reasons why the executable *
26 * file might be covered by the GNU Public License. *
28 * GNAT was originally developed by the GNAT team at New York University. *
29 * Extensive contributions were provided by Ada Core Technologies Inc. *
31 ****************************************************************************/
33 /* Code related to the integration of the GCC mechanism for exception
39 /* In the top-of-tree GCC, tconfig does not include tm.h, but in GCC 3.2
40 it does. To avoid branching raise.c just for that purpose, we kludge by
41 looking for a symbol always defined by tm.h and if it's not defined,
43 #ifndef FIRST_PSEUDO_REGISTER
44 #include "coretypes.h"
60 /* The names of a couple of "standard" routines for unwinding/propagation
61 actually vary depending on the underlying GCC scheme for exception handling
62 (SJLJ or DWARF). We need a consistently named interface to import from
63 a-except, so wrappers are defined here.
65 Besides, even though the compiler is never setup to use the GCC propagation
66 circuitry, it still relies on exceptions internally and part of the sources
67 to handle to exceptions are shared with the run-time library. We need
68 dummy definitions for the wrappers to satisfy the linker in this case.
70 The types to be used by those wrappers in the run-time library are target
71 types exported by unwind.h. We used to piggyback on them for the compiler
72 stubs, but there is no guarantee that unwind.h is always in sight so we
73 define our own set below. These are dummy types as the wrappers are never
74 called in the compiler case. */
80 typedef struct _Unwind_Context _Unwind_Context;
81 typedef struct _Unwind_Exception _Unwind_Exception;
85 typedef void _Unwind_Context;
86 typedef void _Unwind_Exception;
87 typedef int _Unwind_Reason_Code;
92 __gnat_Unwind_RaiseException (_Unwind_Exception *);
95 __gnat_Unwind_ForcedUnwind (_Unwind_Exception *, void *, void *);
98 #ifdef IN_RTS /* For eh personality routine */
101 #include "unwind-dw2-fde.h"
102 #include "unwind-pe.h"
105 /* --------------------------------------------------------------
106 -- The DB stuff below is there for debugging purposes only. --
107 -------------------------------------------------------------- */
109 #define DB_PHASES 0x1
111 #define DB_ACTIONS 0x4
112 #define DB_REGIONS 0x8
114 #define DB_ERR 0x1000
116 /* The "action" stuff below is also there for debugging purposes only. */
120 _Unwind_Action phase;
124 static phase_descriptor phase_descriptors[]
125 = {{ _UA_SEARCH_PHASE, "SEARCH_PHASE" },
126 { _UA_CLEANUP_PHASE, "CLEANUP_PHASE" },
127 { _UA_HANDLER_FRAME, "HANDLER_FRAME" },
128 { _UA_FORCE_UNWIND, "FORCE_UNWIND" },
132 db_accepted_codes (void)
134 static int accepted_codes = -1;
136 if (accepted_codes == -1)
138 char * db_env = (char *) getenv ("EH_DEBUG");
140 accepted_codes = db_env ? (atoi (db_env) | DB_ERR) : 0;
141 /* Arranged for ERR stuff to always be visible when the variable
142 is defined. One may just set the variable to 0 to see the ERR
146 return accepted_codes;
149 #define DB_INDENT_INCREASE 0x01
150 #define DB_INDENT_DECREASE 0x02
151 #define DB_INDENT_OUTPUT 0x04
152 #define DB_INDENT_NEWLINE 0x08
153 #define DB_INDENT_RESET 0x10
155 #define DB_INDENT_UNIT 8
158 db_indent (int requests)
160 static int current_indentation_level = 0;
162 if (requests & DB_INDENT_RESET)
164 current_indentation_level = 0;
167 if (requests & DB_INDENT_INCREASE)
169 current_indentation_level ++;
172 if (requests & DB_INDENT_DECREASE)
174 current_indentation_level --;
177 if (requests & DB_INDENT_NEWLINE)
179 fprintf (stderr, "\n");
182 if (requests & DB_INDENT_OUTPUT)
184 fprintf (stderr, "%*s",
185 current_indentation_level * DB_INDENT_UNIT, " ");
190 static void ATTRIBUTE_PRINTF_2
191 db (int db_code, char * msg_format, ...)
193 if (db_accepted_codes () & db_code)
197 db_indent (DB_INDENT_OUTPUT);
199 va_start (msg_args, msg_format);
200 vfprintf (stderr, msg_format, msg_args);
206 db_phases (int phases)
208 phase_descriptor *a = phase_descriptors;
210 if (! (db_accepted_codes() & DB_PHASES))
213 db (DB_PHASES, "\n");
215 for (; a->description != 0; a++)
216 if (phases & a->phase)
217 db (DB_PHASES, "%s ", a->description);
219 db (DB_PHASES, " :\n");
223 /* ---------------------------------------------------------------
224 -- Now come a set of useful structures and helper routines. --
225 --------------------------------------------------------------- */
227 /* There are three major runtime tables involved, generated by the
228 GCC back-end. Contents slightly vary depending on the underlying
229 implementation scheme (dwarf zero cost / sjlj).
231 =======================================
232 * Tables for the dwarf zero cost case *
233 =======================================
236 -------------------------------------------------------------------
237 * region-start | region-length | landing-pad | first-action-index *
238 -------------------------------------------------------------------
240 Identify possible actions to be taken and where to resume control
241 for that when an exception propagates through a pc inside the region
242 delimited by start and length.
244 A null landing-pad indicates that nothing is to be done.
246 Otherwise, first-action-index provides an entry into the action[]
247 table which heads a list of possible actions to be taken (see below).
249 If it is determined that indeed an action should be taken, that
250 is, if one action filter matches the exception being propagated,
251 then control should be transfered to landing-pad.
253 A null first-action-index indicates that there are only cleanups
257 -------------------------------
258 * action-filter | next-action *
259 -------------------------------
261 This table contains lists (called action chains) of possible actions
262 associated with call-site entries described in the call-site [] table.
263 There is at most one action list per call-site entry.
265 A null action-filter indicates a cleanup.
267 Non null action-filters provide an index into the ttypes [] table
268 (see below), from which information may be retrieved to check if it
269 matches the exception being propagated.
271 action-filter > 0 means there is a regular handler to be run,
273 action-filter < 0 means there is a some "exception_specification"
274 data to retrieve, which is only relevant for C++
275 and should never show up for Ada.
277 next-action indexes the next entry in the list. 0 indicates there is
285 A null value indicates a catch-all handler in C++, and an "others"
288 Non null values are used to match the exception being propagated:
289 In C++ this is a pointer to some rtti data, while in Ada this is an
292 The special id value 1 indicates an "all_others" handler.
294 For C++, this table is actually also used to store "exception
295 specification" data. The differentiation between the two kinds
296 of entries is made by the sign of the associated action filter,
297 which translates into positive or negative offsets from the
298 so called base of the table:
300 Exception Specification data is stored at positive offsets from
301 the ttypes table base, which Exception Type data is stored at
304 ---------------------------------------------------------------------------
306 Here is a quick summary of the tables organization:
308 +-- Unwind_Context (pc, ...)
314 | +=============================================================+
315 | | region-start + length | landing-pad | first-action-index |
316 | +=============================================================+
317 +-> | pc range 0 => no-action 0 => cleanups only |
318 | !0 => jump @ N --+ |
319 +====================================================== | ====+
324 +==========================================================+ |
325 | action-filter | next-action | |
326 +==========================================================+ |
328 | >0 => ttype index for handler ------+ 0 => end of chain | <-+
329 | <0 => ttype index for spec data | |
330 +==================================== | ===================+
334 | Offset negated from
335 +=====================+ | the actual base.
337 +============+=====================+ |
338 | | 0 => "others" | |
339 | ... | 1 => "all others" | <---+
340 | | X => exception id |
341 | handlers +---------------------+
345 +============+=====================+ <<------ Table base
347 | specs | ... | (should not see negative filter
348 | ... | ... | values for Ada).
349 +============+=====================+
352 ============================
353 * Tables for the sjlj case *
354 ============================
356 So called "function contexts" are pushed on a context stack by calls to
357 _Unwind_SjLj_Register on function entry, and popped off at exit points by
358 calls to _Unwind_SjLj_Unregister. The current call_site for a function is
359 updated in the function context as the function's code runs along.
361 The generic unwinding engine in _Unwind_RaiseException walks the function
362 context stack and not the actual call chain.
364 The ACTION and TTYPES tables remain unchanged, which allows to search them
365 during the propagation phase to determine whether or not the propagated
366 exception is handled somewhere. When it is, we only "jump" up once directly
367 to the context where the handler will be found. Besides, this allows "break
368 exception unhandled" to work also
370 The CALL-SITE table is setup differently, though: the pc attached to the
371 unwind context is a direct index into the table, so the entries in this
372 table do not hold region bounds any more.
374 A special index (-1) is used to indicate that no action is possibly
375 connected with the context at hand, so null landing pads cannot appear
378 Additionally, landing pad values in the table do not represent code address
379 to jump at, but so called "dispatch" indices used by a common landing pad
380 for the function to switch to the appropriate post-landing-pad.
382 +-- Unwind_Context (pc, ...)
384 | pc = call-site index
385 | 0 => terminate (should not see this for Ada)
390 | +=====================================+
391 | | landing-pad | first-action-index |
392 | +=====================================+
393 +-> | 0 => cleanups only |
395 +=====================================+
398 ===================================
399 * Basic organization of this unit *
400 ===================================
402 The major point of this unit is to provide an exception propagation
403 personality routine for Ada. This is __gnat_eh_personality.
405 It is provided with a pointer to the propagated exception, an unwind
406 context describing a location the propagation is going through, and a
407 couple of other arguments including a description of the current
410 It shall return to the generic propagation engine what is to be performed
411 next, after possible context adjustments, depending on what it finds in the
412 traversed context (a handler for the exception, a cleanup, nothing, ...),
413 and on the propagation phase.
415 A number of structures and subroutines are used for this purpose, as
418 o region_descriptor: General data associated with the context (base pc,
419 call-site table, action table, ttypes table, ...)
421 o action_descriptor: Data describing the action to be taken for the
422 propagated exception in the provided context (kind of action: nothing,
423 handler, cleanup; pointer to the action table entry, ...).
429 Propagate_Exception (a-exexpr.adb)
432 _Unwind_RaiseException (libgcc)
436 +--> __gnat_eh_personality (context, exception)
438 +--> get_region_descriptor_for (context)
440 +--> get_action_descriptor_for (context, exception, region)
442 | +--> get_call_site_action_for (context, region)
443 | (one version for each underlying scheme)
445 +--> setup_to_install (context)
447 This unit is inspired from the C++ version found in eh_personality.cc,
448 part of libstdc++-v3.
453 /* This is an incomplete "proxy" of the structure of exception objects as
454 built by the GNAT runtime library. Accesses to other fields than the common
455 header are performed through subprogram calls to alleviate the need of an
456 exact counterpart here and potential alignment/size issues for the common
457 header. See a-exexpr.adb. */
461 _Unwind_Exception common;
462 /* ABI header, maximally aligned. */
465 /* The two constants below are specific ttype identifiers for special
466 exception ids. Their type should match what a-exexpr exports. */
468 extern const int __gnat_others_value;
469 #define GNAT_OTHERS ((_Unwind_Ptr) &__gnat_others_value)
471 extern const int __gnat_all_others_value;
472 #define GNAT_ALL_OTHERS ((_Unwind_Ptr) &__gnat_all_others_value)
474 /* Describe the useful region data associated with an unwind context. */
478 /* The base pc of the region. */
481 /* Pointer to the Language Specific Data for the region. */
484 /* Call-Site data associated with this region. */
485 unsigned char call_site_encoding;
486 const unsigned char *call_site_table;
488 /* The base to which are relative landing pad offsets inside the call-site
492 /* Action-Table associated with this region. */
493 const unsigned char *action_table;
495 /* Ttype data associated with this region. */
496 unsigned char ttype_encoding;
497 const unsigned char *ttype_table;
498 _Unwind_Ptr ttype_base;
503 db_region_for (region_descriptor *region, _Unwind_Context *uw_context)
505 _Unwind_Ptr ip = _Unwind_GetIP (uw_context) - 1;
507 if (! (db_accepted_codes () & DB_REGIONS))
510 db (DB_REGIONS, "For ip @ 0x%08x => ", ip);
513 db (DB_REGIONS, "lsda @ 0x%x", region->lsda);
515 db (DB_REGIONS, "no lsda");
517 db (DB_REGIONS, "\n");
520 /* Retrieve the ttype entry associated with FILTER in the REGION's
523 static const _Unwind_Ptr
524 get_ttype_entry_for (region_descriptor *region, long filter)
526 _Unwind_Ptr ttype_entry;
528 filter *= size_of_encoded_value (region->ttype_encoding);
529 read_encoded_value_with_base
530 (region->ttype_encoding, region->ttype_base,
531 region->ttype_table - filter, &ttype_entry);
536 /* Fill out the REGION descriptor for the provided UW_CONTEXT. */
539 get_region_description_for (_Unwind_Context *uw_context,
540 region_descriptor *region)
542 const unsigned char * p;
544 unsigned char lpbase_encoding;
546 /* Get the base address of the lsda information. If the provided context
547 is null or if there is no associated language specific data, there's
548 nothing we can/should do. */
550 = (_Unwind_Ptr) (uw_context
551 ? _Unwind_GetLanguageSpecificData (uw_context) : 0);
556 /* Parse the lsda and fill the region descriptor. */
557 p = (char *)region->lsda;
559 region->base = _Unwind_GetRegionStart (uw_context);
561 /* Find @LPStart, the base to which landing pad offsets are relative. */
562 lpbase_encoding = *p++;
563 if (lpbase_encoding != DW_EH_PE_omit)
564 p = read_encoded_value
565 (uw_context, lpbase_encoding, p, ®ion->lp_base);
567 region->lp_base = region->base;
569 /* Find @TType, the base of the handler and exception spec type data. */
570 region->ttype_encoding = *p++;
571 if (region->ttype_encoding != DW_EH_PE_omit)
573 p = read_uleb128 (p, &tmp);
574 region->ttype_table = p + tmp;
577 region->ttype_table = 0;
580 = base_of_encoded_value (region->ttype_encoding, uw_context);
582 /* Get the encoding and length of the call-site table; the action table
583 immediately follows. */
584 region->call_site_encoding = *p++;
585 region->call_site_table = read_uleb128 (p, &tmp);
587 region->action_table = region->call_site_table + tmp;
591 /* Describe an action to be taken when propagating an exception up to
596 /* Found some call site base data, but need to analyze further
597 before being able to decide. */
600 /* There is nothing relevant in the context at hand. */
603 /* There are only cleanups to run in this context. */
606 /* There is a handler for the exception in this context. */
610 /* filter value for cleanup actions. */
611 const int cleanup_filter = 0;
615 /* The kind of action to be taken. */
618 /* A pointer to the action record entry. */
619 const unsigned char *table_entry;
621 /* Where we should jump to actually take an action (trigger a cleanup or an
622 exception handler). */
623 _Unwind_Ptr landing_pad;
625 /* If we have a handler matching our exception, these are the filter to
626 trigger it and the corresponding id. */
627 _Unwind_Sword ttype_filter;
628 _Unwind_Ptr ttype_entry;
633 db_action_for (action_descriptor *action, _Unwind_Context *uw_context)
635 _Unwind_Ptr ip = _Unwind_GetIP (uw_context) - 1;
637 db (DB_ACTIONS, "For ip @ 0x%08x => ", ip);
639 switch (action->kind)
642 db (DB_ACTIONS, "lpad @ 0x%x, record @ 0x%x\n",
643 action->landing_pad, action->table_entry);
647 db (DB_ACTIONS, "Nothing\n");
651 db (DB_ACTIONS, "Cleanup\n");
655 db (DB_ACTIONS, "Handler, filter = %d\n", action->ttype_filter);
659 db (DB_ACTIONS, "Err? Unexpected action kind !\n");
666 /* Search the call_site_table of REGION for an entry appropriate for the
667 UW_CONTEXT's IP. If one is found, store the associated landing_pad
668 and action_table entry, and set the ACTION kind to unknown for further
669 analysis. Otherwise, set the ACTION kind to nothing.
671 There are two variants of this routine, depending on the underlying
672 mechanism (DWARF/SJLJ), which account for differences in the tables. */
674 #ifdef __USING_SJLJ_EXCEPTIONS__
676 #define __builtin_eh_return_data_regno(x) x
679 get_call_site_action_for (_Unwind_Context *uw_context,
680 region_descriptor *region,
681 action_descriptor *action)
683 /* Subtract 1 because GetIP returns the actual call_site value + 1. */
684 _Unwind_Ptr call_site = _Unwind_GetIP (uw_context) - 1;
686 /* call_site is a direct index into the call-site table, with two special
687 values : -1 for no-action and 0 for "terminate". The latter should never
688 show up for Ada. To test for the former, beware that _Unwind_Ptr might
691 if ((int)call_site < 0)
693 action->kind = nothing;
696 else if (call_site == 0)
698 db (DB_ERR, "========> Err, null call_site for Ada/sjlj\n");
699 action->kind = nothing;
704 _uleb128_t cs_lp, cs_action;
706 /* Let the caller know there may be an action to take, but let it
707 determine the kind. */
708 action->kind = unknown;
710 /* We have a direct index into the call-site table, but this table is
711 made of leb128 values, the encoding length of which is variable. We
712 can't merely compute an offset from the index, then, but have to read
713 all the entries before the one of interest. */
715 const unsigned char *p = region->call_site_table;
718 p = read_uleb128 (p, &cs_lp);
719 p = read_uleb128 (p, &cs_action);
720 } while (--call_site);
722 action->landing_pad = cs_lp + 1;
725 action->table_entry = region->action_table + cs_action - 1;
727 action->table_entry = 0;
733 #else /* !__USING_SJLJ_EXCEPTIONS__ */
736 get_call_site_action_for (_Unwind_Context *uw_context,
737 region_descriptor *region,
738 action_descriptor *action)
740 /* Subtract 1 because GetIP yields a call return address while we are
741 interested in information for the call point. This does not always
742 yield the exact call instruction address but always brings the IP back
743 within the corresponding region.
745 ??? When unwinding up from a signal handler triggered by a trap on some
746 instruction, we usually have the faulting instruction address here and
747 subtracting 1 might get us into the wrong region. */
748 _Unwind_Ptr ip = _Unwind_GetIP (uw_context) - 1;
750 const unsigned char *p = region->call_site_table;
752 /* Unless we are able to determine otherwise... */
753 action->kind = nothing;
757 while (p < region->action_table)
759 _Unwind_Ptr cs_start, cs_len, cs_lp;
760 _uleb128_t cs_action;
762 /* Note that all call-site encodings are "absolute" displacements. */
763 p = read_encoded_value (0, region->call_site_encoding, p, &cs_start);
764 p = read_encoded_value (0, region->call_site_encoding, p, &cs_len);
765 p = read_encoded_value (0, region->call_site_encoding, p, &cs_lp);
766 p = read_uleb128 (p, &cs_action);
769 "c_site @ 0x%08x (+0x%03x), len = %3d, lpad @ 0x%08x (+0x%03x)\n",
770 region->base+cs_start, cs_start, cs_len,
771 region->lp_base+cs_lp, cs_lp);
773 /* The table is sorted, so if we've passed the IP, stop. */
774 if (ip < region->base + cs_start)
777 /* If we have a match, fill the ACTION fields accordingly. */
778 else if (ip < region->base + cs_start + cs_len)
780 /* Let the caller know there may be an action to take, but let it
781 determine the kind. */
782 action->kind = unknown;
785 action->landing_pad = region->lp_base + cs_lp;
787 action->landing_pad = 0;
790 action->table_entry = region->action_table + cs_action - 1;
792 action->table_entry = 0;
794 db (DB_CSITE, "+++\n");
799 db (DB_CSITE, "---\n");
802 #endif /* __USING_SJLJ_EXCEPTIONS__ */
804 /* With CHOICE an exception choice representing an "exception - when"
805 argument, and PROPAGATED_EXCEPTION a pointer to the currently propagated
806 occurrence, return true if the latter matches the former, that is, if
807 PROPAGATED_EXCEPTION is caught by the handling code controlled by CHOICE.
808 This takes care of the special Non_Ada_Error case on VMS. */
810 #define Is_Handled_By_Others __gnat_is_handled_by_others
811 #define Language_For __gnat_language_for
812 #define Import_Code_For __gnat_import_code_for
813 #define EID_For __gnat_eid_for
814 #define Adjust_N_Cleanups_For __gnat_adjust_n_cleanups_for
816 extern bool Is_Handled_By_Others (_Unwind_Ptr eid);
817 extern char Language_For (_Unwind_Ptr eid);
819 extern Exception_Code Import_Code_For (_Unwind_Ptr eid);
821 extern Exception_Id EID_For (_GNAT_Exception * e);
822 extern void Adjust_N_Cleanups_For (_GNAT_Exception * e, int n);
825 is_handled_by (_Unwind_Ptr choice, _GNAT_Exception * propagated_exception)
827 /* Pointer to the GNAT exception data corresponding to the propagated
829 _Unwind_Ptr E = (_Unwind_Ptr) EID_For (propagated_exception);
831 /* Base matching rules: An exception data (id) matches itself, "when
832 all_others" matches anything and "when others" matches anything unless
833 explicitly stated otherwise in the propagated occurrence. */
837 || choice == GNAT_ALL_OTHERS
838 || (choice == GNAT_OTHERS && Is_Handled_By_Others (E));
840 /* In addition, on OpenVMS, Non_Ada_Error matches VMS exceptions, and we
841 may have different exception data pointers that should match for the
842 same condition code, if both an export and an import have been
843 registered. The import code for both the choice and the propagated
844 occurrence are expected to have been masked off regarding severity
845 bits already (at registration time for the former and from within the
846 low level exception vector for the latter). */
848 #define Non_Ada_Error system__aux_dec__non_ada_error
849 extern struct Exception_Data Non_Ada_Error;
852 (Language_For (E) == 'V'
853 && choice != GNAT_OTHERS && choice != GNAT_ALL_OTHERS
854 && ((Language_For (choice) == 'V' && Import_Code_For (choice) != 0
855 && Import_Code_For (choice) == Import_Code_For (E))
856 || choice == (_Unwind_Ptr)&Non_Ada_Error));
862 /* Fill out the ACTION to be taken from propagating UW_EXCEPTION up to
863 UW_CONTEXT in REGION. */
866 get_action_description_for (_Unwind_Context *uw_context,
867 _Unwind_Exception *uw_exception,
868 region_descriptor *region,
869 action_descriptor *action)
871 _GNAT_Exception * gnat_exception = (_GNAT_Exception *) uw_exception;
873 /* Search the call site table first, which may get us a landing pad as well
874 as the head of an action record list. */
875 get_call_site_action_for (uw_context, region, action);
876 db_action_for (action, uw_context);
878 /* If there is not even a call_site entry, we are done. */
879 if (action->kind == nothing)
882 /* Otherwise, check what we have at the place of the call site. */
884 /* No landing pad => no cleanups or handlers. */
885 if (action->landing_pad == 0)
887 action->kind = nothing;
891 /* Landing pad + null table entry => only cleanups. */
892 else if (action->table_entry == 0)
894 action->kind = cleanup;
895 action->ttype_filter = cleanup_filter;
896 /* The filter initialization is not strictly necessary, as cleanup-only
897 landing pads don't look at the filter value. It is there to ensure
898 we don't pass random values and so trigger potential confusion when
899 installing the context later on. */
903 /* Landing pad + Table entry => handlers + possible cleanups. */
906 const unsigned char * p = action->table_entry;
908 _sleb128_t ar_filter, ar_disp;
910 action->kind = nothing;
914 p = read_sleb128 (p, &ar_filter);
915 read_sleb128 (p, &ar_disp);
916 /* Don't assign p here, as it will be incremented by ar_disp
919 /* Null filters are for cleanups. */
920 if (ar_filter == cleanup_filter)
922 action->kind = cleanup;
923 action->ttype_filter = cleanup_filter;
924 /* The filter initialization is required here, to ensure
925 the target landing pad branches to the cleanup code if
926 we happen not to find a matching handler. */
929 /* Positive filters are for regular handlers. */
930 else if (ar_filter > 0)
932 /* See if the filter we have is for an exception which matches
933 the one we are propagating. */
934 _Unwind_Ptr choice = get_ttype_entry_for (region, ar_filter);
936 if (is_handled_by (choice, gnat_exception))
938 action->kind = handler;
939 action->ttype_filter = ar_filter;
940 action->ttype_entry = choice;
945 /* Negative filter values are for C++ exception specifications.
946 Should not be there for Ada :/ */
948 db (DB_ERR, "========> Err, filter < 0 for Ada/dwarf\n");
958 /* Setup in UW_CONTEXT the eh return target IP and data registers, which will
959 be restored with the others and retrieved by the landing pad once the jump
963 setup_to_install (_Unwind_Context *uw_context,
964 _Unwind_Exception *uw_exception,
965 _Unwind_Ptr uw_landing_pad,
968 #ifndef EH_RETURN_DATA_REGNO
969 /* We should not be called if the appropriate underlying support is not
973 /* 1/ exception object pointer, which might be provided back to
974 _Unwind_Resume (and thus to this personality routine) if we are jumping
976 _Unwind_SetGR (uw_context, __builtin_eh_return_data_regno (0),
977 (_Unwind_Word)uw_exception);
979 /* 2/ handler switch value register, which will also be used by the target
980 landing pad to decide what action it shall take. */
981 _Unwind_SetGR (uw_context, __builtin_eh_return_data_regno (1),
982 (_Unwind_Word)uw_filter);
984 /* Setup the address we should jump at to reach the code where there is the
985 "something" we found. */
986 _Unwind_SetIP (uw_context, uw_landing_pad);
990 /* The following is defined from a-except.adb. Its purpose is to enable
991 automatic backtraces upon exception raise, as provided through the
992 GNAT.Traceback facilities. */
993 extern void __gnat_notify_handled_exception (void);
994 extern void __gnat_notify_unhandled_exception (void);
996 /* Below is the eh personality routine per se. We currently assume that only
997 GNU-Ada exceptions are met. */
999 #ifdef __USING_SJLJ_EXCEPTIONS__
1000 #define PERSONALITY_FUNCTION __gnat_eh_personality_sj
1002 #define PERSONALITY_FUNCTION __gnat_eh_personality
1005 /* Major tweak for ia64-vms : the CHF propagation phase calls this personality
1006 routine with sigargs/mechargs arguments and has very specific expectations
1007 on possible return values.
1009 We handle this with a number of specific tricks:
1011 1. We tweak the personality routine prototype to have the "version" and
1012 "phases" two first arguments be void * instead of int and _Unwind_Action
1013 as nominally expected in the GCC context.
1015 This allows us to access the full range of bits passed in every case and
1016 has no impact on the callers side since each argument remains assigned
1017 the same single 64bit slot.
1019 2. We retrieve the corresponding int and _Unwind_Action values within the
1020 routine for regular use with truncating conversions. This is a noop when
1021 called from the libgcc unwinder.
1023 3. We assume we're called by the VMS CHF when unexpected bits are set in
1024 both those values. The incoming arguments are then real sigargs and
1025 mechargs pointers, which we then redirect to __gnat_handle_vms_condition
1026 for proper processing.
1028 #if defined (VMS) && defined (__IA64)
1029 typedef void * version_arg_t;
1030 typedef void * phases_arg_t;
1032 typedef int version_arg_t;
1033 typedef _Unwind_Action phases_arg_t;
1037 PERSONALITY_FUNCTION (version_arg_t version_arg,
1038 phases_arg_t phases_arg,
1039 _Unwind_Exception_Class uw_exception_class,
1040 _Unwind_Exception *uw_exception,
1041 _Unwind_Context *uw_context)
1043 /* Fetch the version and phases args with their nominal ABI types for later
1044 use. This is a noop everywhere except on ia64-vms when called from the
1045 Condition Handling Facility. */
1046 int uw_version = (int) version_arg;
1047 _Unwind_Action uw_phases = (_Unwind_Action) phases_arg;
1049 _GNAT_Exception * gnat_exception = (_GNAT_Exception *) uw_exception;
1051 region_descriptor region;
1052 action_descriptor action;
1054 /* Check that we're called from the ABI context we expect, with a major
1055 possible variation on VMS for IA64. */
1056 if (uw_version != 1)
1058 #if defined (VMS) && defined (__IA64)
1060 /* Assume we're called with sigargs/mechargs arguments if really
1061 unexpected bits are set in our first two formals. Redirect to the
1062 GNAT condition handling code in this case. */
1064 extern long __gnat_handle_vms_condition (void *, void *);
1066 unsigned int version_unexpected_bits_mask = 0xffffff00U;
1067 unsigned int phases_unexpected_bits_mask = 0xffffff00U;
1069 if ((unsigned int)uw_version & version_unexpected_bits_mask
1070 && (unsigned int)uw_phases & phases_unexpected_bits_mask)
1071 return __gnat_handle_vms_condition (version_arg, phases_arg);
1074 return _URC_FATAL_PHASE1_ERROR;
1077 db_indent (DB_INDENT_RESET);
1078 db_phases (uw_phases);
1079 db_indent (DB_INDENT_INCREASE);
1081 /* Get the region description for the context we were provided with. This
1082 will tell us if there is some lsda, call_site, action and/or ttype data
1083 for the associated ip. */
1084 get_region_description_for (uw_context, ®ion);
1085 db_region_for (®ion, uw_context);
1087 /* No LSDA => no handlers or cleanups => we shall unwind further up. */
1089 return _URC_CONTINUE_UNWIND;
1091 /* Search the call-site and action-record tables for the action associated
1093 get_action_description_for (uw_context, uw_exception, ®ion, &action);
1094 db_action_for (&action, uw_context);
1096 /* Whatever the phase, if there is nothing relevant in this frame,
1097 unwinding should just go on. */
1098 if (action.kind == nothing)
1099 return _URC_CONTINUE_UNWIND;
1101 /* If we found something in search phase, we should return a code indicating
1102 what to do next depending on what we found. If we only have cleanups
1103 around, we shall try to unwind further up to find a handler, otherwise,
1104 tell we have a handler, which will trigger the second phase. */
1105 if (uw_phases & _UA_SEARCH_PHASE)
1107 if (action.kind == cleanup)
1109 Adjust_N_Cleanups_For (gnat_exception, 1);
1110 return _URC_CONTINUE_UNWIND;
1114 /* Trigger the appropriate notification routines before the second
1115 phase starts, which ensures the stack is still intact. */
1116 __gnat_notify_handled_exception ();
1118 return _URC_HANDLER_FOUND;
1122 /* We found something in cleanup/handler phase, which might be the handler
1123 or a cleanup for a handled occurrence, or a cleanup for an unhandled
1124 occurrence (we are in a FORCED_UNWIND phase in this case). Install the
1125 context to get there. */
1127 /* If we are going to install a cleanup context, decrement the cleanup
1128 count. This is required in a FORCED_UNWINDing phase (for an unhandled
1129 exception), as this is used from the forced unwinding handler in
1130 Ada.Exceptions.Exception_Propagation to decide whether unwinding should
1131 proceed further or Unhandled_Exception_Terminate should be called. */
1132 if (action.kind == cleanup)
1133 Adjust_N_Cleanups_For (gnat_exception, -1);
1136 (uw_context, uw_exception, action.landing_pad, action.ttype_filter);
1138 return _URC_INSTALL_CONTEXT;
1141 /* Define the consistently named wrappers imported by Propagate_Exception. */
1143 #ifdef __USING_SJLJ_EXCEPTIONS__
1145 #undef _Unwind_RaiseException
1148 __gnat_Unwind_RaiseException (_Unwind_Exception *e)
1150 return _Unwind_SjLj_RaiseException (e);
1154 #undef _Unwind_ForcedUnwind
1157 __gnat_Unwind_ForcedUnwind (_Unwind_Exception *e,
1161 return _Unwind_SjLj_ForcedUnwind (e, handler, argument);
1165 #else /* __USING_SJLJ_EXCEPTIONS__ */
1168 __gnat_Unwind_RaiseException (_Unwind_Exception *e)
1170 return _Unwind_RaiseException (e);
1174 __gnat_Unwind_ForcedUnwind (_Unwind_Exception *e,
1178 return _Unwind_ForcedUnwind (e, handler, argument);
1181 #endif /* __USING_SJLJ_EXCEPTIONS__ */
1186 /* Define the corresponding stubs for the compiler. */
1188 /* We don't want fancy_abort here. */
1192 __gnat_Unwind_RaiseException (_Unwind_Exception *e ATTRIBUTE_UNUSED)
1199 __gnat_Unwind_ForcedUnwind (_Unwind_Exception *e ATTRIBUTE_UNUSED,
1200 void * handler ATTRIBUTE_UNUSED,
1201 void * argument ATTRIBUTE_UNUSED)