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1 | /* Exception (throw catch) mechanism, for GDB, the GNU debugger. |
2 | ||
e2882c85 | 3 | Copyright (C) 1986-2018 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 | |
65630365 PA |
27 | must be different from zero. enum value 0 is reserved for internal |
28 | use as the return value from an initial setjmp(). */ | |
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29 | |
30 | enum return_reason | |
31 | { | |
32 | /* User interrupt. */ | |
33 | RETURN_QUIT = -2, | |
34 | /* Any other error. */ | |
35 | RETURN_ERROR | |
36 | }; | |
37 | ||
38 | #define RETURN_MASK(reason) (1 << (int)(-reason)) | |
39 | ||
40 | typedef enum | |
41 | { | |
42 | RETURN_MASK_QUIT = RETURN_MASK (RETURN_QUIT), | |
43 | RETURN_MASK_ERROR = RETURN_MASK (RETURN_ERROR), | |
44 | RETURN_MASK_ALL = (RETURN_MASK_QUIT | RETURN_MASK_ERROR) | |
45 | } return_mask; | |
46 | ||
47 | /* Describe all exceptions. */ | |
48 | ||
49 | enum errors { | |
50 | GDB_NO_ERROR, | |
51 | ||
52 | /* Any generic error, the corresponding text is in | |
53 | exception.message. */ | |
54 | GENERIC_ERROR, | |
55 | ||
56 | /* Something requested was not found. */ | |
57 | NOT_FOUND_ERROR, | |
58 | ||
59 | /* Thread library lacks support necessary for finding thread local | |
60 | storage. */ | |
61 | TLS_NO_LIBRARY_SUPPORT_ERROR, | |
62 | ||
63 | /* Load module not found while attempting to find thread local storage. */ | |
64 | TLS_LOAD_MODULE_NOT_FOUND_ERROR, | |
65 | ||
66 | /* Thread local storage has not been allocated yet. */ | |
67 | TLS_NOT_ALLOCATED_YET_ERROR, | |
68 | ||
69 | /* Something else went wrong while attempting to find thread local | |
70 | storage. The ``struct gdb_exception'' message field provides | |
71 | more detail. */ | |
72 | TLS_GENERIC_ERROR, | |
73 | ||
74 | /* Problem parsing an XML document. */ | |
75 | XML_PARSE_ERROR, | |
76 | ||
77 | /* Error accessing memory. */ | |
78 | MEMORY_ERROR, | |
79 | ||
80 | /* Value not available. E.g., a register was not collected in a | |
81 | traceframe. */ | |
82 | NOT_AVAILABLE_ERROR, | |
83 | ||
84 | /* Value was optimized out. Note: if the value was a register, this | |
85 | means the register was not saved in the frame. */ | |
86 | OPTIMIZED_OUT_ERROR, | |
87 | ||
216f72a1 | 88 | /* DW_OP_entry_value resolving failed. */ |
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89 | NO_ENTRY_VALUE_ERROR, |
90 | ||
91 | /* Target throwing an error has been closed. Current command should be | |
92 | aborted as the inferior state is no longer valid. */ | |
93 | TARGET_CLOSE_ERROR, | |
94 | ||
95 | /* An undefined command was executed. */ | |
96 | UNDEFINED_COMMAND_ERROR, | |
97 | ||
98 | /* Requested feature, method, mechanism, etc. is not supported. */ | |
99 | NOT_SUPPORTED_ERROR, | |
100 | ||
ef0b411a GB |
101 | /* The number of candidates generated during line completion has |
102 | reached the user's specified limit. This isn't an error, this exception | |
103 | is used to halt searching for more completions, but for consistency | |
104 | "_ERROR" is appended to the name. */ | |
105 | MAX_COMPLETIONS_REACHED_ERROR, | |
106 | ||
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107 | /* Add more errors here. */ |
108 | NR_ERRORS | |
109 | }; | |
110 | ||
111 | struct gdb_exception | |
112 | { | |
113 | enum return_reason reason; | |
114 | enum errors error; | |
115 | const char *message; | |
116 | }; | |
117 | ||
eec461d0 PA |
118 | /* The different exception mechanisms that TRY/CATCH can map to. */ |
119 | ||
ddb6d633 | 120 | /* Make GDB exceptions use setjmp/longjmp behind the scenes. */ |
eec461d0 PA |
121 | #define GDB_XCPT_SJMP 1 |
122 | ||
6290672f | 123 | /* Make GDB exceptions use try/catch behind the scenes. */ |
eec461d0 PA |
124 | #define GDB_XCPT_TRY 2 |
125 | ||
126 | /* Specify this mode to build with TRY/CATCH mapped directly to raw | |
127 | try/catch. GDB won't work correctly, but building that way catches | |
128 | code tryin to break/continue out of the try block, along with | |
129 | spurious code between the TRY and the CATCH block. */ | |
130 | #define GDB_XCPT_RAW_TRY 3 | |
131 | ||
ddb6d633 | 132 | #define GDB_XCPT GDB_XCPT_TRY |
eec461d0 | 133 | |
89525768 PA |
134 | /* Functions to drive the sjlj-based exceptions state machine. Though |
135 | declared here by necessity, these functions should be considered | |
136 | internal to the exceptions subsystem and not used other than via | |
137 | the TRY/CATCH (or TRY_SJLJ/CATCH_SJLJ) macros defined below. */ | |
ff55e1b5 | 138 | |
173981bc | 139 | extern jmp_buf *exceptions_state_mc_init (void); |
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140 | extern int exceptions_state_mc_action_iter (void); |
141 | extern int exceptions_state_mc_action_iter_1 (void); | |
492d29ea | 142 | extern int exceptions_state_mc_catch (struct gdb_exception *, int); |
89525768 PA |
143 | |
144 | /* Same, but for the C++ try/catch-based TRY/CATCH mechanism. */ | |
145 | ||
146 | #if GDB_XCPT != GDB_XCPT_SJMP | |
72df25b2 PA |
147 | extern void *exception_try_scope_entry (void); |
148 | extern void exception_try_scope_exit (void *saved_state); | |
149 | extern void exception_rethrow (void); | |
150 | #endif | |
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151 | |
152 | /* Macro to wrap up standard try/catch behavior. | |
153 | ||
154 | The double loop lets us correctly handle code "break"ing out of the | |
155 | try catch block. (It works as the "break" only exits the inner | |
156 | "while" loop, the outer for loop detects this handling it | |
157 | correctly.) Of course "return" and "goto" are not so lucky. | |
158 | ||
159 | For instance: | |
160 | ||
161 | *INDENT-OFF* | |
162 | ||
492d29ea | 163 | TRY |
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164 | { |
165 | } | |
492d29ea | 166 | CATCH (e, RETURN_MASK_ERROR) |
ff55e1b5 | 167 | { |
492d29ea PA |
168 | switch (e.reason) |
169 | { | |
170 | case RETURN_ERROR: ... | |
171 | } | |
ff55e1b5 | 172 | } |
492d29ea | 173 | END_CATCH |
ff55e1b5 | 174 | |
89525768 PA |
175 | Note that the SJLJ version of the macros are actually named |
176 | TRY_SJLJ/CATCH_SJLJ in order to make it possible to call them even | |
177 | when TRY/CATCH are mapped to C++ try/catch. The SJLJ variants are | |
178 | needed in some cases where gdb exceptions need to cross third-party | |
179 | library code compiled without exceptions support (e.g., | |
180 | readline). */ | |
ff55e1b5 | 181 | |
89525768 | 182 | #define TRY_SJLJ \ |
ff55e1b5 | 183 | { \ |
173981bc | 184 | jmp_buf *buf = \ |
492d29ea | 185 | exceptions_state_mc_init (); \ |
173981bc | 186 | setjmp (*buf); \ |
ff55e1b5 GB |
187 | } \ |
188 | while (exceptions_state_mc_action_iter ()) \ | |
189 | while (exceptions_state_mc_action_iter_1 ()) | |
190 | ||
89525768 | 191 | #define CATCH_SJLJ(EXCEPTION, MASK) \ |
492d29ea PA |
192 | { \ |
193 | struct gdb_exception EXCEPTION; \ | |
194 | if (exceptions_state_mc_catch (&(EXCEPTION), MASK)) | |
195 | ||
89525768 | 196 | #define END_CATCH_SJLJ \ |
492d29ea PA |
197 | } |
198 | ||
89525768 PA |
199 | #if GDB_XCPT == GDB_XCPT_SJMP |
200 | ||
201 | /* If using SJLJ-based exceptions for all exceptions, then provide | |
202 | standard aliases. */ | |
203 | ||
204 | #define TRY TRY_SJLJ | |
205 | #define CATCH CATCH_SJLJ | |
206 | #define END_CATCH END_CATCH_SJLJ | |
207 | ||
eec461d0 PA |
208 | #endif /* GDB_XCPT_SJMP */ |
209 | ||
210 | #if GDB_XCPT == GDB_XCPT_TRY || GDB_XCPT == GDB_XCPT_RAW_TRY | |
72df25b2 PA |
211 | |
212 | /* Prevent error/quit during TRY from calling cleanups established | |
213 | prior to here. This pops out the scope in either case of normal | |
214 | exit or exception exit. */ | |
215 | struct exception_try_scope | |
216 | { | |
217 | exception_try_scope () | |
218 | { | |
219 | saved_state = exception_try_scope_entry (); | |
220 | } | |
221 | ~exception_try_scope () | |
222 | { | |
223 | exception_try_scope_exit (saved_state); | |
224 | } | |
225 | ||
226 | void *saved_state; | |
227 | }; | |
228 | ||
eec461d0 | 229 | #if GDB_XCPT == GDB_XCPT_TRY |
9c6595ab | 230 | |
72df25b2 | 231 | /* We still need to wrap TRY/CATCH in C++ so that cleanups and C++ |
a87c1427 PA |
232 | exceptions can coexist. |
233 | ||
234 | The TRY blocked is wrapped in a do/while(0) so that break/continue | |
235 | within the block works the same as in C. | |
236 | ||
237 | END_CATCH makes sure that even if the CATCH block doesn't want to | |
238 | catch the exception, we stop at every frame in the unwind chain to | |
239 | run its cleanups, which may e.g., have pointers to stack variables | |
240 | that are going to be destroyed. | |
241 | ||
242 | There's an outer scope around the whole TRY/END_CATCH in order to | |
243 | cause a compilation error if you forget to add the END_CATCH at the | |
244 | end a TRY/CATCH construct. */ | |
245 | ||
72df25b2 | 246 | #define TRY \ |
a87c1427 PA |
247 | { \ |
248 | try \ | |
249 | { \ | |
250 | exception_try_scope exception_try_scope_instance; \ | |
251 | do \ | |
252 | { | |
72df25b2 PA |
253 | |
254 | #define CATCH(EXCEPTION, MASK) \ | |
a87c1427 PA |
255 | } while (0); \ |
256 | } \ | |
257 | catch (struct gdb_exception ## _ ## MASK &EXCEPTION) | |
72df25b2 PA |
258 | |
259 | #define END_CATCH \ | |
a87c1427 PA |
260 | catch (...) \ |
261 | { \ | |
262 | exception_rethrow (); \ | |
263 | } \ | |
72df25b2 | 264 | } |
eec461d0 | 265 | |
9c6595ab PA |
266 | #else |
267 | ||
268 | #define TRY try | |
269 | #define CATCH(EXCEPTION, MASK) \ | |
270 | catch (struct gdb_exception ## _ ## MASK &EXCEPTION) | |
271 | #define END_CATCH | |
272 | ||
273 | #endif | |
72df25b2 PA |
274 | |
275 | /* The exception types client code may catch. They're just shims | |
276 | around gdb_exception that add nothing but type info. Which is used | |
277 | is selected depending on the MASK argument passed to CATCH. */ | |
278 | ||
279 | struct gdb_exception_RETURN_MASK_ALL : public gdb_exception | |
280 | { | |
281 | }; | |
282 | ||
283 | struct gdb_exception_RETURN_MASK_ERROR : public gdb_exception_RETURN_MASK_ALL | |
284 | { | |
285 | }; | |
286 | ||
287 | struct gdb_exception_RETURN_MASK_QUIT : public gdb_exception_RETURN_MASK_ALL | |
288 | { | |
289 | }; | |
290 | ||
eec461d0 | 291 | #endif /* GDB_XCPT_TRY || GDB_XCPT_RAW_TRY */ |
72df25b2 | 292 | |
503b1c39 PA |
293 | /* An exception type that inherits from both std::bad_alloc and a gdb |
294 | exception. This is necessary because operator new can only throw | |
295 | std::bad_alloc, and OTOH, we want exceptions thrown due to memory | |
296 | allocation error to be caught by all the CATCH/RETURN_MASK_ALL | |
297 | spread around the codebase. */ | |
298 | ||
299 | struct gdb_quit_bad_alloc | |
300 | : public gdb_exception_RETURN_MASK_QUIT, | |
301 | public std::bad_alloc | |
302 | { | |
303 | explicit gdb_quit_bad_alloc (gdb_exception ex) | |
304 | : std::bad_alloc () | |
305 | { | |
306 | gdb_exception *self = this; | |
307 | ||
308 | *self = ex; | |
309 | } | |
310 | }; | |
311 | ||
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312 | /* *INDENT-ON* */ |
313 | ||
ddb6d633 PA |
314 | /* Throw an exception (as described by "struct gdb_exception"), |
315 | landing in the inner most containing exception handler established | |
316 | using TRY/CATCH. */ | |
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317 | extern void throw_exception (struct gdb_exception exception) |
318 | ATTRIBUTE_NORETURN; | |
89525768 PA |
319 | |
320 | /* Throw an exception by executing a LONG JUMP to the inner most | |
ddb6d633 PA |
321 | containing exception handler established using TRY_SJLJ. Necessary |
322 | in some cases where we need to throw GDB exceptions across | |
323 | third-party library code (e.g., readline). */ | |
89525768 PA |
324 | extern void throw_exception_sjlj (struct gdb_exception exception) |
325 | ATTRIBUTE_NORETURN; | |
326 | ||
327 | /* Convenience wrappers around throw_exception that throw GDB | |
328 | errors. */ | |
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329 | extern void throw_verror (enum errors, const char *fmt, va_list ap) |
330 | ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (2, 0); | |
331 | extern void throw_vquit (const char *fmt, va_list ap) | |
332 | ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (1, 0); | |
333 | extern void throw_error (enum errors error, const char *fmt, ...) | |
334 | ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (2, 3); | |
335 | extern void throw_quit (const char *fmt, ...) | |
336 | ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (1, 2); | |
337 | ||
ad6aff7d PA |
338 | /* A pre-defined non-exception. */ |
339 | extern const struct gdb_exception exception_none; | |
340 | ||
ff55e1b5 | 341 | #endif /* COMMON_EXCEPTIONS_H */ |