1 /* Exception (throw catch) mechanism, for GDB, the GNU debugger.
3 Copyright (C) 1986-2014 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/>. */
24 #include "gdb_setjmp.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94 aborted as the inferior state is no longer valid.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 /* Add more errors here. */
109 enum return_reason reason;
114 /* A pre-defined non-exception. */
115 extern const struct gdb_exception exception_none;
117 /* Functions to drive the exceptions state m/c (internal to
119 SIGJMP_BUF *exceptions_state_mc_init (volatile struct
120 gdb_exception *exception,
122 int exceptions_state_mc_action_iter (void);
123 int exceptions_state_mc_action_iter_1 (void);
125 /* Macro to wrap up standard try/catch behavior.
127 The double loop lets us correctly handle code "break"ing out of the
128 try catch block. (It works as the "break" only exits the inner
129 "while" loop, the outer for loop detects this handling it
130 correctly.) Of course "return" and "goto" are not so lucky.
136 volatile struct gdb_exception e;
137 TRY_CATCH (e, RETURN_MASK_ERROR)
142 case RETURN_ERROR: ...
147 #define TRY_CATCH(EXCEPTION,MASK) \
150 exceptions_state_mc_init (&(EXCEPTION), (MASK)); \
153 while (exceptions_state_mc_action_iter ()) \
154 while (exceptions_state_mc_action_iter_1 ())
159 /* If E is an exception, print it's error message on the specified
160 stream. For _fprintf, prefix the message with PREFIX... */
161 extern void exception_print (struct ui_file *file, struct gdb_exception e);
162 extern void exception_fprintf (struct ui_file *file, struct gdb_exception e,
164 ...) ATTRIBUTE_PRINTF (3, 4);
166 /* Throw an exception (as described by "struct gdb_exception"). Will
167 execute a LONG JUMP to the inner most containing exception handler
168 established using catch_exceptions() (or similar).
170 Code normally throws an exception using error() et.al. For various
171 reaons, GDB also contains code that throws an exception directly.
172 For instance, the remote*.c targets contain CNTRL-C signal handlers
173 that propogate the QUIT event up the exception chain. ``This could
174 be a good thing or a dangerous thing.'' -- the Existential
177 extern void throw_exception (struct gdb_exception exception)
179 extern void throw_verror (enum errors, const char *fmt, va_list ap)
180 ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (2, 0);
181 extern void throw_vquit (const char *fmt, va_list ap)
182 ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (1, 0);
183 extern void throw_error (enum errors error, const char *fmt, ...)
184 ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (2, 3);
185 extern void throw_quit (const char *fmt, ...)
186 ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (1, 2);
188 /* Call FUNC(UIOUT, FUNC_ARGS) but wrapped within an exception
189 handler. If an exception (enum return_reason) is thrown using
190 throw_exception() than all cleanups installed since
191 catch_exceptions() was entered are invoked, the (-ve) exception
192 value is then returned by catch_exceptions. If FUNC() returns
193 normally (with a positive or zero return value) then that value is
194 returned by catch_exceptions(). It is an internal_error() for
195 FUNC() to return a negative value.
197 For the period of the FUNC() call: UIOUT is installed as the output
198 builder; ERRSTRING is installed as the error/quit message; and a
199 new cleanup_chain is established. The old values are restored
200 before catch_exceptions() returns.
202 The variant catch_exceptions_with_msg() is the same as
203 catch_exceptions() but adds the ability to return an allocated
204 copy of the gdb error message. This is used when a silent error is
205 issued and the caller wants to manually issue the error message.
207 MASK specifies what to catch; it is normally set to
208 RETURN_MASK_ALL, if for no other reason than that the code which
209 calls catch_errors might not be set up to deal with a quit which
210 isn't caught. But if the code can deal with it, it generally
211 should be RETURN_MASK_ERROR, unless for some reason it is more
212 useful to abort only the portion of the operation inside the
213 catch_errors. Note that quit should return to the command line
214 fairly quickly, even if some further processing is being done.
216 FIXME; cagney/2001-08-13: The need to override the global UIOUT
217 builder variable should just go away.
219 This function supersedes catch_errors().
221 This function uses SETJMP() and LONGJUMP(). */
224 typedef int (catch_exceptions_ftype) (struct ui_out *ui_out, void *args);
225 extern int catch_exceptions (struct ui_out *uiout,
226 catch_exceptions_ftype *func, void *func_args,
228 typedef void (catch_exception_ftype) (struct ui_out *ui_out, void *args);
229 extern int catch_exceptions_with_msg (struct ui_out *uiout,
230 catch_exceptions_ftype *func,
235 /* If CATCH_ERRORS_FTYPE throws an error, catch_errors() returns zero
236 otherwize the result from CATCH_ERRORS_FTYPE is returned. It is
237 probably useful for CATCH_ERRORS_FTYPE to always return a non-zero
238 value. It's unfortunate that, catch_errors() does not return an
239 indication of the exact exception that it caught - quit_flag might
242 This function is superseded by catch_exceptions(). */
244 typedef int (catch_errors_ftype) (void *);
245 extern int catch_errors (catch_errors_ftype *, void *, char *, return_mask);