1 /* Exception (throw catch) mechanism, for GDB, the GNU debugger.
3 Copyright (C) 1986-2016 Free Software Foundation, Inc.
5 This file is part of GDB.
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.
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.
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/>. */
20 #ifndef COMMON_EXCEPTIONS_H
21 #define COMMON_EXCEPTIONS_H
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
36 /* Any other error. */
40 #define RETURN_MASK(reason) (1 << (int)(-reason))
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
)
49 /* Describe all exceptions. */
54 /* Any generic error, the corresponding text is in
58 /* Something requested was not found. */
61 /* Thread library lacks support necessary for finding thread local
63 TLS_NO_LIBRARY_SUPPORT_ERROR
,
65 /* Load module not found while attempting to find thread local storage. */
66 TLS_LOAD_MODULE_NOT_FOUND_ERROR
,
68 /* Thread local storage has not been allocated yet. */
69 TLS_NOT_ALLOCATED_YET_ERROR
,
71 /* Something else went wrong while attempting to find thread local
72 storage. The ``struct gdb_exception'' message field provides
76 /* Problem parsing an XML document. */
79 /* Error accessing memory. */
82 /* Value not available. E.g., a register was not collected in a
86 /* Value was optimized out. Note: if the value was a register, this
87 means the register was not saved in the frame. */
90 /* DW_OP_GNU_entry_value resolving failed. */
93 /* Target throwing an error has been closed. Current command should be
94 aborted as the inferior state is no longer valid. */
97 /* An undefined command was executed. */
98 UNDEFINED_COMMAND_ERROR
,
100 /* Requested feature, method, mechanism, etc. is not supported. */
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
,
109 /* Add more errors here. */
115 enum return_reason reason
;
120 /* The different exception mechanisms that TRY/CATCH can map to. */
122 /* Make GDB exceptions use setjmp/longjmp behind the scenes. */
123 #define GDB_XCPT_SJMP 1
125 /* Make GDB exceptions use try/catch behind the scenes. */
126 #define GDB_XCPT_TRY 2
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
134 #define GDB_XCPT GDB_XCPT_TRY
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. */
141 extern jmp_buf *exceptions_state_mc_init (void);
142 extern int exceptions_state_mc_action_iter (void);
143 extern int exceptions_state_mc_action_iter_1 (void);
144 extern int exceptions_state_mc_catch (struct gdb_exception
*, int);
146 /* Same, but for the C++ try/catch-based TRY/CATCH mechanism. */
148 #if GDB_XCPT != GDB_XCPT_SJMP
149 extern void *exception_try_scope_entry (void);
150 extern void exception_try_scope_exit (void *saved_state
);
151 extern void exception_rethrow (void);
154 /* Macro to wrap up standard try/catch behavior.
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.
168 CATCH (e, RETURN_MASK_ERROR)
172 case RETURN_ERROR: ...
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.,
187 exceptions_state_mc_init (); \
190 while (exceptions_state_mc_action_iter ()) \
191 while (exceptions_state_mc_action_iter_1 ())
193 #define CATCH_SJLJ(EXCEPTION, MASK) \
195 struct gdb_exception EXCEPTION; \
196 if (exceptions_state_mc_catch (&(EXCEPTION), MASK))
198 #define END_CATCH_SJLJ \
201 #if GDB_XCPT == GDB_XCPT_SJMP
203 /* If using SJLJ-based exceptions for all exceptions, then provide
207 #define CATCH CATCH_SJLJ
208 #define END_CATCH END_CATCH_SJLJ
210 #endif /* GDB_XCPT_SJMP */
212 #if GDB_XCPT == GDB_XCPT_TRY || GDB_XCPT == GDB_XCPT_RAW_TRY
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
219 exception_try_scope ()
221 saved_state
= exception_try_scope_entry ();
223 ~exception_try_scope ()
225 exception_try_scope_exit (saved_state
);
231 #if GDB_XCPT == GDB_XCPT_TRY
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
240 exception_try_scope exception_try_scope_instance; \
244 #define CATCH(EXCEPTION, MASK) \
247 catch (struct gdb_exception ## _ ## MASK &EXCEPTION)
252 exception_rethrow (); \
258 #define CATCH(EXCEPTION, MASK) \
259 catch (struct gdb_exception ## _ ## MASK &EXCEPTION)
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. */
268 struct gdb_exception_RETURN_MASK_ALL
: public gdb_exception
272 struct gdb_exception_RETURN_MASK_ERROR
: public gdb_exception_RETURN_MASK_ALL
276 struct gdb_exception_RETURN_MASK_QUIT
: public gdb_exception_RETURN_MASK_ALL
280 #endif /* GDB_XCPT_TRY || GDB_XCPT_RAW_TRY */
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. */
288 struct gdb_quit_bad_alloc
289 : public gdb_exception_RETURN_MASK_QUIT
,
290 public std::bad_alloc
292 explicit gdb_quit_bad_alloc (gdb_exception ex
)
295 gdb_exception
*self
= this;
303 /* Throw an exception (as described by "struct gdb_exception"),
304 landing in the inner most containing exception handler established
306 extern void throw_exception (struct gdb_exception exception
)
309 /* Throw an exception by executing a LONG JUMP to the inner most
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). */
313 extern void throw_exception_sjlj (struct gdb_exception exception
)
316 /* Convenience wrappers around throw_exception that throw GDB
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);
327 /* A pre-defined non-exception. */
328 extern const struct gdb_exception exception_none
;
330 #endif /* COMMON_EXCEPTIONS_H */