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1 | /* Exception (throw catch) mechanism, for GDB, the GNU debugger. |
2 | ||
61baf725 | 3 | Copyright (C) 1986-2017 Free Software Foundation, Inc. |
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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 | #ifndef COMMON_EXCEPTIONS_H | |
21 | #define COMMON_EXCEPTIONS_H | |
22 | ||
173981bc | 23 | #include <setjmp.h> |
503b1c39 | 24 | #include <new> |
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25 | |
26 | /* Reasons for calling throw_exceptions(). NOTE: all reason values | |
27 | must be less than zero. enum value 0 is reserved for internal use | |
28 | as the return value from an initial setjmp(). The function | |
29 | catch_exceptions() reserves values >= 0 as legal results from its | |
30 | wrapped function. */ | |
31 | ||
32 | enum return_reason | |
33 | { | |
34 | /* User interrupt. */ | |
35 | RETURN_QUIT = -2, | |
36 | /* Any other error. */ | |
37 | RETURN_ERROR | |
38 | }; | |
39 | ||
40 | #define RETURN_MASK(reason) (1 << (int)(-reason)) | |
41 | ||
42 | typedef enum | |
43 | { | |
44 | RETURN_MASK_QUIT = RETURN_MASK (RETURN_QUIT), | |
45 | RETURN_MASK_ERROR = RETURN_MASK (RETURN_ERROR), | |
46 | RETURN_MASK_ALL = (RETURN_MASK_QUIT | RETURN_MASK_ERROR) | |
47 | } return_mask; | |
48 | ||
49 | /* Describe all exceptions. */ | |
50 | ||
51 | enum errors { | |
52 | GDB_NO_ERROR, | |
53 | ||
54 | /* Any generic error, the corresponding text is in | |
55 | exception.message. */ | |
56 | GENERIC_ERROR, | |
57 | ||
58 | /* Something requested was not found. */ | |
59 | NOT_FOUND_ERROR, | |
60 | ||
61 | /* Thread library lacks support necessary for finding thread local | |
62 | storage. */ | |
63 | TLS_NO_LIBRARY_SUPPORT_ERROR, | |
64 | ||
65 | /* Load module not found while attempting to find thread local storage. */ | |
66 | TLS_LOAD_MODULE_NOT_FOUND_ERROR, | |
67 | ||
68 | /* Thread local storage has not been allocated yet. */ | |
69 | TLS_NOT_ALLOCATED_YET_ERROR, | |
70 | ||
71 | /* Something else went wrong while attempting to find thread local | |
72 | storage. The ``struct gdb_exception'' message field provides | |
73 | more detail. */ | |
74 | TLS_GENERIC_ERROR, | |
75 | ||
76 | /* Problem parsing an XML document. */ | |
77 | XML_PARSE_ERROR, | |
78 | ||
79 | /* Error accessing memory. */ | |
80 | MEMORY_ERROR, | |
81 | ||
82 | /* Value not available. E.g., a register was not collected in a | |
83 | traceframe. */ | |
84 | NOT_AVAILABLE_ERROR, | |
85 | ||
86 | /* Value was optimized out. Note: if the value was a register, this | |
87 | means the register was not saved in the frame. */ | |
88 | OPTIMIZED_OUT_ERROR, | |
89 | ||
216f72a1 | 90 | /* DW_OP_entry_value resolving failed. */ |
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91 | NO_ENTRY_VALUE_ERROR, |
92 | ||
93 | /* Target throwing an error has been closed. Current command should be | |
94 | aborted as the inferior state is no longer valid. */ | |
95 | TARGET_CLOSE_ERROR, | |
96 | ||
97 | /* An undefined command was executed. */ | |
98 | UNDEFINED_COMMAND_ERROR, | |
99 | ||
100 | /* Requested feature, method, mechanism, etc. is not supported. */ | |
101 | NOT_SUPPORTED_ERROR, | |
102 | ||
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103 | /* The number of candidates generated during line completion has |
104 | reached the user's specified limit. This isn't an error, this exception | |
105 | is used to halt searching for more completions, but for consistency | |
106 | "_ERROR" is appended to the name. */ | |
107 | MAX_COMPLETIONS_REACHED_ERROR, | |
108 | ||
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109 | /* Add more errors here. */ |
110 | NR_ERRORS | |
111 | }; | |
112 | ||
113 | struct gdb_exception | |
114 | { | |
115 | enum return_reason reason; | |
116 | enum errors error; | |
117 | const char *message; | |
118 | }; | |
119 | ||
eec461d0 PA |
120 | /* The different exception mechanisms that TRY/CATCH can map to. */ |
121 | ||
ddb6d633 | 122 | /* Make GDB exceptions use setjmp/longjmp behind the scenes. */ |
eec461d0 PA |
123 | #define GDB_XCPT_SJMP 1 |
124 | ||
6290672f | 125 | /* Make GDB exceptions use try/catch behind the scenes. */ |
eec461d0 PA |
126 | #define GDB_XCPT_TRY 2 |
127 | ||
128 | /* Specify this mode to build with TRY/CATCH mapped directly to raw | |
129 | try/catch. GDB won't work correctly, but building that way catches | |
130 | code tryin to break/continue out of the try block, along with | |
131 | spurious code between the TRY and the CATCH block. */ | |
132 | #define GDB_XCPT_RAW_TRY 3 | |
133 | ||
ddb6d633 | 134 | #define GDB_XCPT GDB_XCPT_TRY |
eec461d0 | 135 | |
89525768 PA |
136 | /* Functions to drive the sjlj-based exceptions state machine. Though |
137 | declared here by necessity, these functions should be considered | |
138 | internal to the exceptions subsystem and not used other than via | |
139 | the TRY/CATCH (or TRY_SJLJ/CATCH_SJLJ) macros defined below. */ | |
ff55e1b5 | 140 | |
173981bc | 141 | extern jmp_buf *exceptions_state_mc_init (void); |
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142 | extern int exceptions_state_mc_action_iter (void); |
143 | extern int exceptions_state_mc_action_iter_1 (void); | |
492d29ea | 144 | extern int exceptions_state_mc_catch (struct gdb_exception *, int); |
89525768 PA |
145 | |
146 | /* Same, but for the C++ try/catch-based TRY/CATCH mechanism. */ | |
147 | ||
148 | #if GDB_XCPT != GDB_XCPT_SJMP | |
72df25b2 PA |
149 | extern void *exception_try_scope_entry (void); |
150 | extern void exception_try_scope_exit (void *saved_state); | |
151 | extern void exception_rethrow (void); | |
152 | #endif | |
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153 | |
154 | /* Macro to wrap up standard try/catch behavior. | |
155 | ||
156 | The double loop lets us correctly handle code "break"ing out of the | |
157 | try catch block. (It works as the "break" only exits the inner | |
158 | "while" loop, the outer for loop detects this handling it | |
159 | correctly.) Of course "return" and "goto" are not so lucky. | |
160 | ||
161 | For instance: | |
162 | ||
163 | *INDENT-OFF* | |
164 | ||
492d29ea | 165 | TRY |
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166 | { |
167 | } | |
492d29ea | 168 | CATCH (e, RETURN_MASK_ERROR) |
ff55e1b5 | 169 | { |
492d29ea PA |
170 | switch (e.reason) |
171 | { | |
172 | case RETURN_ERROR: ... | |
173 | } | |
ff55e1b5 | 174 | } |
492d29ea | 175 | END_CATCH |
ff55e1b5 | 176 | |
89525768 PA |
177 | Note that the SJLJ version of the macros are actually named |
178 | TRY_SJLJ/CATCH_SJLJ in order to make it possible to call them even | |
179 | when TRY/CATCH are mapped to C++ try/catch. The SJLJ variants are | |
180 | needed in some cases where gdb exceptions need to cross third-party | |
181 | library code compiled without exceptions support (e.g., | |
182 | readline). */ | |
ff55e1b5 | 183 | |
89525768 | 184 | #define TRY_SJLJ \ |
ff55e1b5 | 185 | { \ |
173981bc | 186 | jmp_buf *buf = \ |
492d29ea | 187 | exceptions_state_mc_init (); \ |
173981bc | 188 | setjmp (*buf); \ |
ff55e1b5 GB |
189 | } \ |
190 | while (exceptions_state_mc_action_iter ()) \ | |
191 | while (exceptions_state_mc_action_iter_1 ()) | |
192 | ||
89525768 | 193 | #define CATCH_SJLJ(EXCEPTION, MASK) \ |
492d29ea PA |
194 | { \ |
195 | struct gdb_exception EXCEPTION; \ | |
196 | if (exceptions_state_mc_catch (&(EXCEPTION), MASK)) | |
197 | ||
89525768 | 198 | #define END_CATCH_SJLJ \ |
492d29ea PA |
199 | } |
200 | ||
89525768 PA |
201 | #if GDB_XCPT == GDB_XCPT_SJMP |
202 | ||
203 | /* If using SJLJ-based exceptions for all exceptions, then provide | |
204 | standard aliases. */ | |
205 | ||
206 | #define TRY TRY_SJLJ | |
207 | #define CATCH CATCH_SJLJ | |
208 | #define END_CATCH END_CATCH_SJLJ | |
209 | ||
eec461d0 PA |
210 | #endif /* GDB_XCPT_SJMP */ |
211 | ||
212 | #if GDB_XCPT == GDB_XCPT_TRY || GDB_XCPT == GDB_XCPT_RAW_TRY | |
72df25b2 PA |
213 | |
214 | /* Prevent error/quit during TRY from calling cleanups established | |
215 | prior to here. This pops out the scope in either case of normal | |
216 | exit or exception exit. */ | |
217 | struct exception_try_scope | |
218 | { | |
219 | exception_try_scope () | |
220 | { | |
221 | saved_state = exception_try_scope_entry (); | |
222 | } | |
223 | ~exception_try_scope () | |
224 | { | |
225 | exception_try_scope_exit (saved_state); | |
226 | } | |
227 | ||
228 | void *saved_state; | |
229 | }; | |
230 | ||
eec461d0 | 231 | #if GDB_XCPT == GDB_XCPT_TRY |
9c6595ab | 232 | |
72df25b2 PA |
233 | /* We still need to wrap TRY/CATCH in C++ so that cleanups and C++ |
234 | exceptions can coexist. The TRY blocked is wrapped in a | |
235 | do/while(0) so that break/continue within the block works the same | |
236 | as in C. */ | |
237 | #define TRY \ | |
238 | try \ | |
239 | { \ | |
240 | exception_try_scope exception_try_scope_instance; \ | |
241 | do \ | |
242 | { | |
243 | ||
244 | #define CATCH(EXCEPTION, MASK) \ | |
245 | } while (0); \ | |
246 | } \ | |
247 | catch (struct gdb_exception ## _ ## MASK &EXCEPTION) | |
248 | ||
249 | #define END_CATCH \ | |
250 | catch (...) \ | |
251 | { \ | |
252 | exception_rethrow (); \ | |
253 | } | |
eec461d0 | 254 | |
9c6595ab PA |
255 | #else |
256 | ||
257 | #define TRY try | |
258 | #define CATCH(EXCEPTION, MASK) \ | |
259 | catch (struct gdb_exception ## _ ## MASK &EXCEPTION) | |
260 | #define END_CATCH | |
261 | ||
262 | #endif | |
72df25b2 PA |
263 | |
264 | /* The exception types client code may catch. They're just shims | |
265 | around gdb_exception that add nothing but type info. Which is used | |
266 | is selected depending on the MASK argument passed to CATCH. */ | |
267 | ||
268 | struct gdb_exception_RETURN_MASK_ALL : public gdb_exception | |
269 | { | |
270 | }; | |
271 | ||
272 | struct gdb_exception_RETURN_MASK_ERROR : public gdb_exception_RETURN_MASK_ALL | |
273 | { | |
274 | }; | |
275 | ||
276 | struct gdb_exception_RETURN_MASK_QUIT : public gdb_exception_RETURN_MASK_ALL | |
277 | { | |
278 | }; | |
279 | ||
eec461d0 | 280 | #endif /* GDB_XCPT_TRY || GDB_XCPT_RAW_TRY */ |
72df25b2 | 281 | |
503b1c39 PA |
282 | /* An exception type that inherits from both std::bad_alloc and a gdb |
283 | exception. This is necessary because operator new can only throw | |
284 | std::bad_alloc, and OTOH, we want exceptions thrown due to memory | |
285 | allocation error to be caught by all the CATCH/RETURN_MASK_ALL | |
286 | spread around the codebase. */ | |
287 | ||
288 | struct gdb_quit_bad_alloc | |
289 | : public gdb_exception_RETURN_MASK_QUIT, | |
290 | public std::bad_alloc | |
291 | { | |
292 | explicit gdb_quit_bad_alloc (gdb_exception ex) | |
293 | : std::bad_alloc () | |
294 | { | |
295 | gdb_exception *self = this; | |
296 | ||
297 | *self = ex; | |
298 | } | |
299 | }; | |
300 | ||
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301 | /* *INDENT-ON* */ |
302 | ||
ddb6d633 PA |
303 | /* Throw an exception (as described by "struct gdb_exception"), |
304 | landing in the inner most containing exception handler established | |
305 | using TRY/CATCH. */ | |
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306 | extern void throw_exception (struct gdb_exception exception) |
307 | ATTRIBUTE_NORETURN; | |
89525768 PA |
308 | |
309 | /* Throw an exception by executing a LONG JUMP to the inner most | |
ddb6d633 PA |
310 | containing exception handler established using TRY_SJLJ. Necessary |
311 | in some cases where we need to throw GDB exceptions across | |
312 | third-party library code (e.g., readline). */ | |
89525768 PA |
313 | extern void throw_exception_sjlj (struct gdb_exception exception) |
314 | ATTRIBUTE_NORETURN; | |
315 | ||
316 | /* Convenience wrappers around throw_exception that throw GDB | |
317 | errors. */ | |
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318 | extern void throw_verror (enum errors, const char *fmt, va_list ap) |
319 | ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (2, 0); | |
320 | extern void throw_vquit (const char *fmt, va_list ap) | |
321 | ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (1, 0); | |
322 | extern void throw_error (enum errors error, const char *fmt, ...) | |
323 | ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (2, 3); | |
324 | extern void throw_quit (const char *fmt, ...) | |
325 | ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (1, 2); | |
326 | ||
ad6aff7d PA |
327 | /* A pre-defined non-exception. */ |
328 | extern const struct gdb_exception exception_none; | |
329 | ||
ff55e1b5 | 330 | #endif /* COMMON_EXCEPTIONS_H */ |