1 /* Exception handling and frame unwind runtime interface routines. -*- C -*-
2 Copyright (C) 2001 Free Software Foundation, Inc.
4 This file is part of GNU CC.
6 GNU CC is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2, or (at your option)
11 GNU CC is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with GNU CC; see the file COPYING. If not, write to
18 the Free Software Foundation, 59 Temple Place - Suite 330,
19 Boston, MA 02111-1307, USA. */
21 /* This is derived from the C++ ABI for IA-64. Where we diverge
22 for cross-architecture compatibility are noted with "@@@".
23 This file is included from unwind-dw2.c or unwind-ia64.c. */
25 /* Subroutine of _Unwind_RaiseException also invoked from _Unwind_Resume.
27 Unwind the stack calling the personality routine to find both the
28 exception handler and intermediary cleanup code. We'll only locate
29 the first such frame here. Cleanup code will call back into
30 _Unwind_Resume and we'll continue Phase 2 there. */
32 static _Unwind_Reason_Code
33 _Unwind_RaiseException_Phase2(struct _Unwind_Exception *exc,
34 struct _Unwind_Context *context)
36 _Unwind_Reason_Code code;
40 _Unwind_FrameState fs;
43 code = uw_frame_state_for (context, &fs);
45 /* Identify when we've reached the designated handler context. */
46 match_handler = (uw_identify_context (context) == exc->private_2
47 ? _UA_HANDLER_FRAME : 0);
49 if (code != _URC_NO_REASON)
50 /* Some error encountered. Ususally the unwinder doesn't
51 diagnose these and merely crashes. */
52 return _URC_FATAL_PHASE2_ERROR;
54 /* Unwind successful. Run the personality routine, if any. */
57 code = (*fs.personality) (1, _UA_CLEANUP_PHASE | match_handler,
58 exc->exception_class, exc, context);
59 if (code == _URC_INSTALL_CONTEXT)
61 if (code != _URC_CONTINUE_UNWIND)
62 return _URC_FATAL_PHASE2_ERROR;
65 /* Don't let us unwind past the handler context. */
69 uw_update_context (context, &fs);
76 /* Raise an exception, passing along the given exception object. */
79 _Unwind_RaiseException(struct _Unwind_Exception *exc)
81 struct _Unwind_Context this_context, cur_context;
82 _Unwind_Reason_Code code;
84 uw_init_context (&this_context);
85 cur_context = this_context;
87 /* Phase 1: Search. Unwind the stack, calling the personality routine
88 with the _UA_SEARCH_PHASE flag set. Do not modify the stack yet. */
91 _Unwind_FrameState fs;
93 code = uw_frame_state_for (&cur_context, &fs);
95 if (code == _URC_END_OF_STACK)
96 /* Hit end of stack with no handler found. */
97 return _URC_END_OF_STACK;
99 if (code != _URC_NO_REASON)
100 /* Some error encountered. Ususally the unwinder doesn't
101 diagnose these and merely crashes. */
102 return _URC_FATAL_PHASE1_ERROR;
104 /* Unwind successful. Run the personality routine, if any. */
107 code = (*fs.personality) (1, _UA_SEARCH_PHASE, exc->exception_class,
109 if (code == _URC_HANDLER_FOUND)
111 else if (code != _URC_CONTINUE_UNWIND)
112 return _URC_FATAL_PHASE1_ERROR;
115 uw_update_context (&cur_context, &fs);
118 /* Indicate to _Unwind_Resume and associated subroutines that this
119 is not a forced unwind. Further, note where we found a handler. */
121 exc->private_2 = uw_identify_context (&cur_context);
123 cur_context = this_context;
124 code = _Unwind_RaiseException_Phase2 (exc, &cur_context);
125 if (code != _URC_INSTALL_CONTEXT)
128 uw_install_context (&this_context, &cur_context);
132 /* Subroutine of _Unwind_ForcedUnwind also invoked from _Unwind_Resume. */
134 static _Unwind_Reason_Code
135 _Unwind_ForcedUnwind_Phase2(struct _Unwind_Exception *exc,
136 struct _Unwind_Context *context)
138 _Unwind_Stop_Fn stop = (_Unwind_Stop_Fn) (_Unwind_Ptr) exc->private_1;
139 void *stop_argument = (void *) (_Unwind_Ptr) exc->private_2;
140 _Unwind_Reason_Code code, stop_code;
144 _Unwind_FrameState fs;
146 code = uw_frame_state_for (context, &fs);
147 if (code != _URC_NO_REASON && code != _URC_END_OF_STACK)
148 return _URC_FATAL_PHASE2_ERROR;
150 /* Unwind successful. */
151 stop_code = (*stop) (1, _UA_FORCE_UNWIND | _UA_CLEANUP_PHASE,
152 exc->exception_class, exc, context, stop_argument);
153 if (stop_code != _URC_NO_REASON)
154 return _URC_FATAL_PHASE2_ERROR;
156 /* Stop didn't want to do anything. Invoke the personality
157 handler, if applicable, to run cleanups. */
158 if (code == _URC_END_OF_STACK)
163 code = (*fs.personality) (1, _UA_FORCE_UNWIND | _UA_CLEANUP_PHASE,
164 exc->exception_class, exc, context);
165 if (code == _URC_INSTALL_CONTEXT)
167 if (code != _URC_CONTINUE_UNWIND)
168 return _URC_FATAL_PHASE2_ERROR;
171 uw_update_context (context, &fs);
178 /* Raise an exception for forced unwinding. */
181 _Unwind_ForcedUnwind (struct _Unwind_Exception *exc,
182 _Unwind_Stop_Fn stop, void * stop_argument)
184 struct _Unwind_Context this_context, cur_context;
185 _Unwind_Reason_Code code;
187 uw_init_context (&this_context);
188 cur_context = this_context;
190 exc->private_1 = (_Unwind_Ptr) stop;
191 exc->private_2 = (_Unwind_Ptr) stop_argument;
193 code = _Unwind_ForcedUnwind_Phase2 (exc, &cur_context);
194 if (code != _URC_INSTALL_CONTEXT)
197 uw_install_context (&this_context, &cur_context);
201 /* Resume propagation of an existing exception. This is used after
202 e.g. executing cleanup code, and not to implement rethrowing. */
205 _Unwind_Resume (struct _Unwind_Exception *exc)
207 struct _Unwind_Context this_context, cur_context;
208 _Unwind_Reason_Code code;
210 uw_init_context (&this_context);
211 cur_context = this_context;
213 /* Choose between continuing to process _Unwind_RaiseException
214 or _Unwind_ForcedUnwind. */
215 if (exc->private_1 == 0)
216 code = _Unwind_RaiseException_Phase2 (exc, &cur_context);
218 code = _Unwind_ForcedUnwind_Phase2 (exc, &cur_context);
220 if (code != _URC_INSTALL_CONTEXT)
223 uw_install_context (&this_context, &cur_context);
226 /* A convenience function that calls the exception_cleanup field. */
229 _Unwind_DeleteException (struct _Unwind_Exception *exc)
231 (*exc->exception_cleanup) (_URC_FOREIGN_EXCEPTION_CAUGHT, exc);