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1 | /* Exception (throw catch) mechanism, for GDB, the GNU debugger. |
2 | ||
42a4f53d | 3 | Copyright (C) 1986-2019 Free Software Foundation, Inc. |
ff55e1b5 GB |
4 | |
5 | This file is part of GDB. | |
6 | ||
7 | This program is free software; you can redistribute it and/or modify | |
8 | it under the terms of the GNU General Public License as published by | |
9 | the Free Software Foundation; either version 3 of the License, or | |
10 | (at your option) any later version. | |
11 | ||
12 | This program is distributed in the hope that it will be useful, | |
13 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 | GNU General Public License for more details. | |
16 | ||
17 | You should have received a copy of the GNU General Public License | |
18 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ | |
19 | ||
20 | #include "common-defs.h" | |
21 | #include "common-exceptions.h" | |
3d6e9d23 | 22 | #include <forward_list> |
ff55e1b5 GB |
23 | |
24 | /* Possible catcher states. */ | |
25 | enum catcher_state { | |
26 | /* Initial state, a new catcher has just been created. */ | |
27 | CATCHER_CREATED, | |
28 | /* The catch code is running. */ | |
29 | CATCHER_RUNNING, | |
30 | CATCHER_RUNNING_1, | |
31 | /* The catch code threw an exception. */ | |
32 | CATCHER_ABORTING | |
33 | }; | |
34 | ||
35 | /* Possible catcher actions. */ | |
36 | enum catcher_action { | |
37 | CATCH_ITER, | |
38 | CATCH_ITER_1, | |
39 | CATCH_THROWING | |
40 | }; | |
41 | ||
42 | struct catcher | |
43 | { | |
3d6e9d23 | 44 | enum catcher_state state = CATCHER_CREATED; |
ff55e1b5 | 45 | /* Jump buffer pointing back at the exception handler. */ |
173981bc | 46 | jmp_buf buf; |
ff55e1b5 | 47 | /* Status buffer belonging to the exception handler. */ |
cc06b668 | 48 | struct gdb_exception exception; |
ff55e1b5 GB |
49 | }; |
50 | ||
51 | /* Where to go for throw_exception(). */ | |
3d6e9d23 | 52 | static std::forward_list<struct catcher> catchers; |
ff55e1b5 | 53 | |
173981bc | 54 | jmp_buf * |
3d6e9d23 | 55 | exceptions_state_mc_init () |
ff55e1b5 | 56 | { |
3d6e9d23 TT |
57 | catchers.emplace_front (); |
58 | return &catchers.front ().buf; | |
ff55e1b5 GB |
59 | } |
60 | ||
61 | /* Catcher state machine. Returns non-zero if the m/c should be run | |
62 | again, zero if it should abort. */ | |
63 | ||
64 | static int | |
65 | exceptions_state_mc (enum catcher_action action) | |
66 | { | |
3d6e9d23 | 67 | switch (catchers.front ().state) |
ff55e1b5 GB |
68 | { |
69 | case CATCHER_CREATED: | |
70 | switch (action) | |
71 | { | |
72 | case CATCH_ITER: | |
73 | /* Allow the code to run the catcher. */ | |
3d6e9d23 | 74 | catchers.front ().state = CATCHER_RUNNING; |
ff55e1b5 GB |
75 | return 1; |
76 | default: | |
77 | internal_error (__FILE__, __LINE__, _("bad state")); | |
78 | } | |
79 | case CATCHER_RUNNING: | |
80 | switch (action) | |
81 | { | |
82 | case CATCH_ITER: | |
492d29ea | 83 | /* No error/quit has occured. */ |
ff55e1b5 GB |
84 | return 0; |
85 | case CATCH_ITER_1: | |
3d6e9d23 | 86 | catchers.front ().state = CATCHER_RUNNING_1; |
ff55e1b5 GB |
87 | return 1; |
88 | case CATCH_THROWING: | |
3d6e9d23 | 89 | catchers.front ().state = CATCHER_ABORTING; |
ff55e1b5 GB |
90 | /* See also throw_exception. */ |
91 | return 1; | |
92 | default: | |
93 | internal_error (__FILE__, __LINE__, _("bad switch")); | |
94 | } | |
95 | case CATCHER_RUNNING_1: | |
96 | switch (action) | |
97 | { | |
98 | case CATCH_ITER: | |
99 | /* The did a "break" from the inner while loop. */ | |
ff55e1b5 GB |
100 | return 0; |
101 | case CATCH_ITER_1: | |
3d6e9d23 | 102 | catchers.front ().state = CATCHER_RUNNING; |
ff55e1b5 GB |
103 | return 0; |
104 | case CATCH_THROWING: | |
3d6e9d23 | 105 | catchers.front ().state = CATCHER_ABORTING; |
ff55e1b5 GB |
106 | /* See also throw_exception. */ |
107 | return 1; | |
108 | default: | |
109 | internal_error (__FILE__, __LINE__, _("bad switch")); | |
110 | } | |
111 | case CATCHER_ABORTING: | |
112 | switch (action) | |
113 | { | |
114 | case CATCH_ITER: | |
115 | { | |
492d29ea PA |
116 | /* Exit normally if this catcher can handle this |
117 | exception. The caller analyses the func return | |
118 | values. */ | |
119 | return 0; | |
ff55e1b5 GB |
120 | } |
121 | default: | |
122 | internal_error (__FILE__, __LINE__, _("bad state")); | |
123 | } | |
124 | default: | |
125 | internal_error (__FILE__, __LINE__, _("bad switch")); | |
126 | } | |
127 | } | |
128 | ||
492d29ea PA |
129 | int |
130 | exceptions_state_mc_catch (struct gdb_exception *exception, | |
131 | int mask) | |
132 | { | |
3d6e9d23 TT |
133 | *exception = std::move (catchers.front ().exception); |
134 | catchers.pop_front (); | |
492d29ea PA |
135 | |
136 | if (exception->reason < 0) | |
137 | { | |
138 | if (mask & RETURN_MASK (exception->reason)) | |
139 | { | |
72df25b2 | 140 | /* Exit normally and let the caller handle the |
492d29ea PA |
141 | exception. */ |
142 | return 1; | |
143 | } | |
144 | ||
145 | /* The caller didn't request that the event be caught, relay the | |
89525768 PA |
146 | event to the next exception_catch/CATCH_SJLJ. */ |
147 | throw_exception_sjlj (*exception); | |
492d29ea PA |
148 | } |
149 | ||
150 | /* No exception was thrown. */ | |
151 | return 0; | |
152 | } | |
153 | ||
ff55e1b5 GB |
154 | int |
155 | exceptions_state_mc_action_iter (void) | |
156 | { | |
157 | return exceptions_state_mc (CATCH_ITER); | |
158 | } | |
159 | ||
160 | int | |
161 | exceptions_state_mc_action_iter_1 (void) | |
162 | { | |
163 | return exceptions_state_mc (CATCH_ITER_1); | |
164 | } | |
165 | ||
bf469271 | 166 | /* Return EXCEPTION to the nearest containing CATCH_SJLJ block. */ |
ff55e1b5 GB |
167 | |
168 | void | |
c6fdd8b2 | 169 | throw_exception_sjlj (const struct gdb_exception &exception) |
ff55e1b5 | 170 | { |
bf469271 PA |
171 | /* Jump to the nearest CATCH_SJLJ block, communicating REASON to |
172 | that call via setjmp's return value. Note that REASON can't be | |
173 | zero, by definition in common-exceptions.h. */ | |
ff55e1b5 | 174 | exceptions_state_mc (CATCH_THROWING); |
c6fdd8b2 | 175 | enum return_reason reason = exception.reason; |
3d6e9d23 | 176 | catchers.front ().exception = exception; |
c6fdd8b2 | 177 | longjmp (catchers.front ().buf, reason); |
89525768 PA |
178 | } |
179 | ||
89525768 PA |
180 | /* Implementation of throw_exception that uses C++ try/catch. */ |
181 | ||
26003a20 | 182 | void |
94aeb44b | 183 | throw_exception (gdb_exception &&exception) |
89525768 | 184 | { |
72df25b2 | 185 | if (exception.reason == RETURN_QUIT) |
94aeb44b | 186 | throw gdb_exception_quit (std::move (exception)); |
72df25b2 | 187 | else if (exception.reason == RETURN_ERROR) |
94aeb44b | 188 | throw gdb_exception_error (std::move (exception)); |
72df25b2 PA |
189 | else |
190 | gdb_assert_not_reached ("invalid return reason"); | |
89525768 PA |
191 | } |
192 | ||
ff55e1b5 GB |
193 | static void ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (3, 0) |
194 | throw_it (enum return_reason reason, enum errors error, const char *fmt, | |
195 | va_list ap) | |
196 | { | |
26003a20 | 197 | if (reason == RETURN_QUIT) |
56be6ea8 | 198 | throw gdb_exception_quit (fmt, ap); |
26003a20 | 199 | else if (reason == RETURN_ERROR) |
56be6ea8 | 200 | throw gdb_exception_error (error, fmt, ap); |
26003a20 TT |
201 | else |
202 | gdb_assert_not_reached ("invalid return reason"); | |
ff55e1b5 GB |
203 | } |
204 | ||
205 | void | |
206 | throw_verror (enum errors error, const char *fmt, va_list ap) | |
207 | { | |
208 | throw_it (RETURN_ERROR, error, fmt, ap); | |
209 | } | |
210 | ||
211 | void | |
212 | throw_vquit (const char *fmt, va_list ap) | |
213 | { | |
214 | throw_it (RETURN_QUIT, GDB_NO_ERROR, fmt, ap); | |
215 | } | |
216 | ||
217 | void | |
218 | throw_error (enum errors error, const char *fmt, ...) | |
219 | { | |
220 | va_list args; | |
221 | ||
222 | va_start (args, fmt); | |
223 | throw_verror (error, fmt, args); | |
224 | va_end (args); | |
225 | } | |
226 | ||
227 | void | |
228 | throw_quit (const char *fmt, ...) | |
229 | { | |
230 | va_list args; | |
231 | ||
232 | va_start (args, fmt); | |
233 | throw_vquit (fmt, args); | |
234 | va_end (args); | |
235 | } |