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
25 /* Reasons for calling throw_exceptions(). NOTE: all reason values
26 must be less than zero. enum value 0 is reserved for internal use
27 as the return value from an initial setjmp(). The function
28 catch_exceptions() reserves values >= 0 as legal results from its
35 /* Any other error. */
39 #define RETURN_MASK(reason) (1 << (int)(-reason))
43 RETURN_MASK_QUIT = RETURN_MASK (RETURN_QUIT),
44 RETURN_MASK_ERROR = RETURN_MASK (RETURN_ERROR),
45 RETURN_MASK_ALL = (RETURN_MASK_QUIT | RETURN_MASK_ERROR)
48 /* Describe all exceptions. */
53 /* Any generic error, the corresponding text is in
57 /* Something requested was not found. */
60 /* Thread library lacks support necessary for finding thread local
62 TLS_NO_LIBRARY_SUPPORT_ERROR,
64 /* Load module not found while attempting to find thread local storage. */
65 TLS_LOAD_MODULE_NOT_FOUND_ERROR,
67 /* Thread local storage has not been allocated yet. */
68 TLS_NOT_ALLOCATED_YET_ERROR,
70 /* Something else went wrong while attempting to find thread local
71 storage. The ``struct gdb_exception'' message field provides
75 /* Problem parsing an XML document. */
78 /* Error accessing memory. */
81 /* Value not available. E.g., a register was not collected in a
85 /* Value was optimized out. Note: if the value was a register, this
86 means the register was not saved in the frame. */
89 /* DW_OP_GNU_entry_value resolving failed. */
92 /* Target throwing an error has been closed. Current command should be
93 aborted as the inferior state is no longer valid. */
96 /* An undefined command was executed. */
97 UNDEFINED_COMMAND_ERROR,
99 /* Requested feature, method, mechanism, etc. is not supported. */
102 /* The number of candidates generated during line completion has
103 reached the user's specified limit. This isn't an error, this exception
104 is used to halt searching for more completions, but for consistency
105 "_ERROR" is appended to the name. */
106 MAX_COMPLETIONS_REACHED_ERROR,
108 /* Add more errors here. */
114 enum return_reason reason;
119 /* The different exception mechanisms that TRY/CATCH can map to. */
121 /* Make GDB exceptions use setjmp/longjmp behind the scenes. This is
122 the only mode supported when GDB is built as a C program. */
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
135 # define GDB_XCPT GDB_XCPT_TRY
137 # define GDB_XCPT GDB_XCPT_SJMP
140 /* Functions to drive the exceptions state machine. Though declared
141 here by necessity, these functions should be considered internal to
142 the exceptions subsystem and not used other than via the TRY/CATCH
143 macros defined below. */
145 #if GDB_XCPT == GDB_XCPT_SJMP
146 extern jmp_buf *exceptions_state_mc_init (void);
147 extern int exceptions_state_mc_action_iter (void);
148 extern int exceptions_state_mc_action_iter_1 (void);
149 extern int exceptions_state_mc_catch (struct gdb_exception *, int);
151 extern void *exception_try_scope_entry (void);
152 extern void exception_try_scope_exit (void *saved_state);
153 extern void exception_rethrow (void);
156 /* Macro to wrap up standard try/catch behavior.
158 The double loop lets us correctly handle code "break"ing out of the
159 try catch block. (It works as the "break" only exits the inner
160 "while" loop, the outer for loop detects this handling it
161 correctly.) Of course "return" and "goto" are not so lucky.
170 CATCH (e, RETURN_MASK_ERROR)
174 case RETURN_ERROR: ...
181 #if GDB_XCPT == GDB_XCPT_SJMP
186 exceptions_state_mc_init (); \
189 while (exceptions_state_mc_action_iter ()) \
190 while (exceptions_state_mc_action_iter_1 ())
192 #define CATCH(EXCEPTION, MASK) \
194 struct gdb_exception EXCEPTION; \
195 if (exceptions_state_mc_catch (&(EXCEPTION), MASK))
200 #endif /* GDB_XCPT_SJMP */
202 #if GDB_XCPT == GDB_XCPT_TRY || GDB_XCPT == GDB_XCPT_RAW_TRY
204 /* Prevent error/quit during TRY from calling cleanups established
205 prior to here. This pops out the scope in either case of normal
206 exit or exception exit. */
207 struct exception_try_scope
209 exception_try_scope ()
211 saved_state = exception_try_scope_entry ();
213 ~exception_try_scope ()
215 exception_try_scope_exit (saved_state);
221 #if GDB_XCPT == GDB_XCPT_TRY
223 /* We still need to wrap TRY/CATCH in C++ so that cleanups and C++
224 exceptions can coexist. The TRY blocked is wrapped in a
225 do/while(0) so that break/continue within the block works the same
230 exception_try_scope exception_try_scope_instance; \
234 #define CATCH(EXCEPTION, MASK) \
237 catch (struct gdb_exception ## _ ## MASK &EXCEPTION)
242 exception_rethrow (); \
248 #define CATCH(EXCEPTION, MASK) \
249 catch (struct gdb_exception ## _ ## MASK &EXCEPTION)
254 /* The exception types client code may catch. They're just shims
255 around gdb_exception that add nothing but type info. Which is used
256 is selected depending on the MASK argument passed to CATCH. */
258 struct gdb_exception_RETURN_MASK_ALL : public gdb_exception
262 struct gdb_exception_RETURN_MASK_ERROR : public gdb_exception_RETURN_MASK_ALL
266 struct gdb_exception_RETURN_MASK_QUIT : public gdb_exception_RETURN_MASK_ALL
270 #endif /* GDB_XCPT_TRY || GDB_XCPT_RAW_TRY */
274 /* Throw an exception (as described by "struct gdb_exception"). Will
275 execute a LONG JUMP to the inner most containing exception handler
276 established using catch_exceptions() (or similar).
278 Code normally throws an exception using error() et.al. For various
279 reaons, GDB also contains code that throws an exception directly.
280 For instance, the remote*.c targets contain CNTRL-C signal handlers
281 that propogate the QUIT event up the exception chain. ``This could
282 be a good thing or a dangerous thing.'' -- the Existential
285 extern void throw_exception (struct gdb_exception exception)
287 extern void throw_verror (enum errors, const char *fmt, va_list ap)
288 ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (2, 0);
289 extern void throw_vquit (const char *fmt, va_list ap)
290 ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (1, 0);
291 extern void throw_error (enum errors error, const char *fmt, ...)
292 ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (2, 3);
293 extern void throw_quit (const char *fmt, ...)
294 ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (1, 2);
296 /* A pre-defined non-exception. */
297 extern const struct gdb_exception exception_none;
299 #endif /* COMMON_EXCEPTIONS_H */