| 1 | /* Exception (throw catch) mechanism, for GDB, the GNU debugger. |
| 2 | |
| 3 | Copyright (C) 1986-2014 Free Software Foundation, Inc. |
| 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 | |
| 23 | #include "gdb_setjmp.h" |
| 24 | |
| 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 |
| 29 | wrapped function. */ |
| 30 | |
| 31 | enum return_reason |
| 32 | { |
| 33 | /* User interrupt. */ |
| 34 | RETURN_QUIT = -2, |
| 35 | /* Any other error. */ |
| 36 | RETURN_ERROR |
| 37 | }; |
| 38 | |
| 39 | #define RETURN_MASK(reason) (1 << (int)(-reason)) |
| 40 | |
| 41 | typedef enum |
| 42 | { |
| 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) |
| 46 | } return_mask; |
| 47 | |
| 48 | /* Describe all exceptions. */ |
| 49 | |
| 50 | enum errors { |
| 51 | GDB_NO_ERROR, |
| 52 | |
| 53 | /* Any generic error, the corresponding text is in |
| 54 | exception.message. */ |
| 55 | GENERIC_ERROR, |
| 56 | |
| 57 | /* Something requested was not found. */ |
| 58 | NOT_FOUND_ERROR, |
| 59 | |
| 60 | /* Thread library lacks support necessary for finding thread local |
| 61 | storage. */ |
| 62 | TLS_NO_LIBRARY_SUPPORT_ERROR, |
| 63 | |
| 64 | /* Load module not found while attempting to find thread local storage. */ |
| 65 | TLS_LOAD_MODULE_NOT_FOUND_ERROR, |
| 66 | |
| 67 | /* Thread local storage has not been allocated yet. */ |
| 68 | TLS_NOT_ALLOCATED_YET_ERROR, |
| 69 | |
| 70 | /* Something else went wrong while attempting to find thread local |
| 71 | storage. The ``struct gdb_exception'' message field provides |
| 72 | more detail. */ |
| 73 | TLS_GENERIC_ERROR, |
| 74 | |
| 75 | /* Problem parsing an XML document. */ |
| 76 | XML_PARSE_ERROR, |
| 77 | |
| 78 | /* Error accessing memory. */ |
| 79 | MEMORY_ERROR, |
| 80 | |
| 81 | /* Value not available. E.g., a register was not collected in a |
| 82 | traceframe. */ |
| 83 | NOT_AVAILABLE_ERROR, |
| 84 | |
| 85 | /* Value was optimized out. Note: if the value was a register, this |
| 86 | means the register was not saved in the frame. */ |
| 87 | OPTIMIZED_OUT_ERROR, |
| 88 | |
| 89 | /* DW_OP_GNU_entry_value resolving failed. */ |
| 90 | NO_ENTRY_VALUE_ERROR, |
| 91 | |
| 92 | /* Target throwing an error has been closed. Current command should be |
| 93 | aborted as the inferior state is no longer valid. */ |
| 94 | TARGET_CLOSE_ERROR, |
| 95 | |
| 96 | /* An undefined command was executed. */ |
| 97 | UNDEFINED_COMMAND_ERROR, |
| 98 | |
| 99 | /* Requested feature, method, mechanism, etc. is not supported. */ |
| 100 | NOT_SUPPORTED_ERROR, |
| 101 | |
| 102 | /* Add more errors here. */ |
| 103 | NR_ERRORS |
| 104 | }; |
| 105 | |
| 106 | struct gdb_exception |
| 107 | { |
| 108 | enum return_reason reason; |
| 109 | enum errors error; |
| 110 | const char *message; |
| 111 | }; |
| 112 | |
| 113 | /* Functions to drive the exceptions state machine. Though declared |
| 114 | here by necessity, these functions should be considered internal to |
| 115 | the exceptions subsystem and not used other than via the TRY_CATCH |
| 116 | macro defined below. */ |
| 117 | |
| 118 | extern SIGJMP_BUF *exceptions_state_mc_init (volatile struct |
| 119 | gdb_exception *exception, |
| 120 | return_mask mask); |
| 121 | extern int exceptions_state_mc_action_iter (void); |
| 122 | extern int exceptions_state_mc_action_iter_1 (void); |
| 123 | |
| 124 | /* Macro to wrap up standard try/catch behavior. |
| 125 | |
| 126 | The double loop lets us correctly handle code "break"ing out of the |
| 127 | try catch block. (It works as the "break" only exits the inner |
| 128 | "while" loop, the outer for loop detects this handling it |
| 129 | correctly.) Of course "return" and "goto" are not so lucky. |
| 130 | |
| 131 | For instance: |
| 132 | |
| 133 | *INDENT-OFF* |
| 134 | |
| 135 | volatile struct gdb_exception e; |
| 136 | TRY_CATCH (e, RETURN_MASK_ERROR) |
| 137 | { |
| 138 | } |
| 139 | switch (e.reason) |
| 140 | { |
| 141 | case RETURN_ERROR: ... |
| 142 | } |
| 143 | |
| 144 | */ |
| 145 | |
| 146 | #define TRY_CATCH(EXCEPTION,MASK) \ |
| 147 | { \ |
| 148 | SIGJMP_BUF *buf = \ |
| 149 | exceptions_state_mc_init (&(EXCEPTION), (MASK)); \ |
| 150 | SIGSETJMP (*buf); \ |
| 151 | } \ |
| 152 | while (exceptions_state_mc_action_iter ()) \ |
| 153 | while (exceptions_state_mc_action_iter_1 ()) |
| 154 | |
| 155 | /* *INDENT-ON* */ |
| 156 | |
| 157 | /* Hook to allow client-specific actions to be performed prior to |
| 158 | throwing an exception. This function must be provided by the |
| 159 | client, and will be called before any cleanups are run. */ |
| 160 | |
| 161 | extern void prepare_to_throw_exception (void); |
| 162 | |
| 163 | /* Throw an exception (as described by "struct gdb_exception"). Will |
| 164 | execute a LONG JUMP to the inner most containing exception handler |
| 165 | established using catch_exceptions() (or similar). |
| 166 | |
| 167 | Code normally throws an exception using error() et.al. For various |
| 168 | reaons, GDB also contains code that throws an exception directly. |
| 169 | For instance, the remote*.c targets contain CNTRL-C signal handlers |
| 170 | that propogate the QUIT event up the exception chain. ``This could |
| 171 | be a good thing or a dangerous thing.'' -- the Existential |
| 172 | Wombat. */ |
| 173 | |
| 174 | extern void throw_exception (struct gdb_exception exception) |
| 175 | ATTRIBUTE_NORETURN; |
| 176 | extern void throw_verror (enum errors, const char *fmt, va_list ap) |
| 177 | ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (2, 0); |
| 178 | extern void throw_vquit (const char *fmt, va_list ap) |
| 179 | ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (1, 0); |
| 180 | extern void throw_error (enum errors error, const char *fmt, ...) |
| 181 | ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (2, 3); |
| 182 | extern void throw_quit (const char *fmt, ...) |
| 183 | ATTRIBUTE_NORETURN ATTRIBUTE_PRINTF (1, 2); |
| 184 | |
| 185 | #endif /* COMMON_EXCEPTIONS_H */ |