1 /* Private implementation details of interface between gdb and its 2 extension languages. 3 4 Copyright (C) 2014-2020 Free Software Foundation, Inc. 5 6 This file is part of GDB. 7 8 This program is free software; you can redistribute it and/or modify 9 it under the terms of the GNU General Public License as published by 10 the Free Software Foundation; either version 3 of the License, or 11 (at your option) any later version. 12 13 This program is distributed in the hope that it will be useful, 14 but WITHOUT ANY WARRANTY; without even the implied warranty of 15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16 GNU General Public License for more details. 17 18 You should have received a copy of the GNU General Public License 19 along with this program. If not, see <http://www.gnu.org/licenses/>. */ 20 21 #ifndef EXTENSION_PRIV_H 22 #define EXTENSION_PRIV_H 23 24 #include "extension.h" 25 #include <signal.h> 26 #include "cli/cli-script.h" 27 28 /* High level description of an extension/scripting language. 29 An entry for each is compiled into GDB regardless of whether the support 30 is present. This is done so that we can issue meaningful errors if the 31 support is not compiled in. */ 32 33 struct extension_language_defn 34 { 35 /* Enum of the extension language. */ 36 enum extension_language language; 37 38 /* The name of the extension language, lowercase. E.g., python. */ 39 const char *name; 40 41 /* The capitalized name of the extension language. 42 For python this is "Python". For gdb this is "GDB". */ 43 const char *capitalized_name; 44 45 /* The file suffix of this extension language. E.g., ".py". */ 46 const char *suffix; 47 48 /* The suffix of per-objfile scripts to auto-load. 49 E.g., When the program loads libfoo.so, look for libfoo.so-gdb.py. */ 50 const char *auto_load_suffix; 51 52 /* We support embedding external extension language code in GDB's own 53 scripting language. We do this by having a special command that begins 54 the extension language snippet, and terminate it with "end". 55 This specifies the control type used to implement this. */ 56 enum command_control_type cli_control_type; 57 58 /* A pointer to the "methods" to load scripts in this language, 59 or NULL if the support is not compiled into GDB. */ 60 const struct extension_language_script_ops *script_ops; 61 62 /* Either a pointer to the "methods" of the extension language interface 63 or NULL if the support is not compiled into GDB. 64 This is also NULL for GDB's own scripting language which is relatively 65 primitive, and doesn't provide these features. */ 66 const struct extension_language_ops *ops; 67 }; 68 69 /* The interface for loading scripts from external extension languages, 70 as well as GDB's own scripting language. 71 All of these methods are required to be implemented. 72 73 By convention all of these functions take a pseudo-this parameter 74 as the first argument. */ 75 76 struct extension_language_script_ops 77 { 78 /* Load a script. This is called, e.g., via the "source" command. 79 If there's an error while processing the script this function may, 80 but is not required to, throw an error. */ 81 script_sourcer_func *script_sourcer; 82 83 /* Load a script attached to an objfile. 84 If there's an error while processing the script this function may, 85 but is not required to, throw an error. */ 86 objfile_script_sourcer_func *objfile_script_sourcer; 87 88 /* Execute a script attached to an objfile. 89 If there's an error while processing the script this function may, 90 but is not required to, throw an error. */ 91 objfile_script_executor_func *objfile_script_executor; 92 93 /* Return non-zero if auto-loading scripts in this extension language 94 is enabled. */ 95 int (*auto_load_enabled) (const struct extension_language_defn *); 96 }; 97 98 /* The interface for making calls from GDB to an external extension 99 language. This is for non-script-loading related functionality, like 100 pretty-printing, etc. The reason these are separated out is GDB's own 101 scripting language makes use of extension_language_script_opts, but it 102 makes no use of these. There is no (current) intention to split 103 extension_language_ops up any further. 104 All of these methods are optional and may be NULL, except where 105 otherwise indicated. 106 107 By convention all of these functions take a pseudo-this parameter 108 as the first argument. */ 109 110 struct extension_language_ops 111 { 112 /* Called at the end of gdb initialization to give the extension language 113 an opportunity to finish up. This is useful for things like adding 114 new commands where one has to wait until gdb itself is initialized. */ 115 void (*finish_initialization) (const struct extension_language_defn *); 116 117 /* Return non-zero if the extension language successfully initialized. 118 This method is required. */ 119 int (*initialized) (const struct extension_language_defn *); 120 121 /* Process a sequence of commands embedded in GDB's own scripting language. 122 E.g., 123 python 124 print 42 125 end */ 126 void (*eval_from_control_command) (const struct extension_language_defn *, 127 struct command_line *); 128 129 /* Type-printing support: 130 start_type_printers, apply_type_printers, free_type_printers. 131 These methods are optional and may be NULL, but if one of them is 132 implemented then they all must be. */ 133 134 /* Called before printing a type. */ 135 void (*start_type_printers) (const struct extension_language_defn *, 136 struct ext_lang_type_printers *); 137 138 /* Try to pretty-print TYPE. If successful the pretty-printed type is 139 stored in *PRETTIED_TYPE, and the caller must free it. 140 Returns EXT_LANG_RC_OK upon success, EXT_LANG_RC_NOP if the type 141 is not recognized, and EXT_LANG_RC_ERROR if an error was encountered. 142 This function has a bit of a funny name, since it actually applies 143 recognizers, but this seemed clearer given the start_type_printers 144 and free_type_printers functions. */ 145 enum ext_lang_rc (*apply_type_printers) 146 (const struct extension_language_defn *, 147 const struct ext_lang_type_printers *, 148 struct type *, char **prettied_type); 149 150 /* Called after a type has been printed to give the type pretty-printer 151 mechanism an opportunity to clean up. */ 152 void (*free_type_printers) (const struct extension_language_defn *, 153 struct ext_lang_type_printers *); 154 155 /* Try to pretty-print a value, onto stdio stream STREAM according 156 to OPTIONS. VAL is the object to print. Returns EXT_LANG_RC_OK 157 upon success, EXT_LANG_RC_NOP if the value is not recognized, and 158 EXT_LANG_RC_ERROR if an error was encountered. */ 159 enum ext_lang_rc (*apply_val_pretty_printer) 160 (const struct extension_language_defn *, 161 struct value *val, struct ui_file *stream, int recurse, 162 const struct value_print_options *options, 163 const struct language_defn *language); 164 165 /* GDB access to the "frame filter" feature. 166 FRAME is the source frame to start frame-filter invocation. FLAGS is an 167 integer holding the flags for printing. The following elements of 168 the FRAME_FILTER_FLAGS enum denotes the make-up of FLAGS: 169 PRINT_LEVEL is a flag indicating whether to print the frame's 170 relative level in the output. PRINT_FRAME_INFO is a flag that 171 indicates whether this function should print the frame 172 information, PRINT_ARGS is a flag that indicates whether to print 173 frame arguments, and PRINT_LOCALS, likewise, with frame local 174 variables. ARGS_TYPE is an enumerator describing the argument 175 format, OUT is the output stream to print. FRAME_LOW is the 176 beginning of the slice of frames to print, and FRAME_HIGH is the 177 upper limit of the frames to count. Returns SCR_BT_ERROR on error, 178 or SCR_BT_COMPLETED on success. */ 179 enum ext_lang_bt_status (*apply_frame_filter) 180 (const struct extension_language_defn *, 181 struct frame_info *frame, frame_filter_flags flags, 182 enum ext_lang_frame_args args_type, 183 struct ui_out *out, int frame_low, int frame_high); 184 185 /* Update values held by the extension language when OBJFILE is discarded. 186 New global types must be created for every such value, which must then be 187 updated to use the new types. 188 This function typically just iterates over all appropriate values and 189 calls preserve_one_value for each one. 190 COPIED_TYPES is used to prevent cycles / duplicates and is passed to 191 preserve_one_value. */ 192 void (*preserve_values) (const struct extension_language_defn *, 193 struct objfile *objfile, htab_t copied_types); 194 195 /* Return non-zero if there is a stop condition for the breakpoint. 196 This is used to implement the restriction that a breakpoint may have 197 at most one condition. */ 198 int (*breakpoint_has_cond) (const struct extension_language_defn *, 199 struct breakpoint *); 200 201 /* Return a value of enum ext_lang_bp_stop indicating if there is a stop 202 condition for the breakpoint, and if so whether the program should 203 stop. This is called when the program has stopped at the specified 204 breakpoint. 205 While breakpoints can have at most one condition, this is called for 206 every extension language, even if another extension language has a 207 "stop" method: other kinds of breakpoints may be implemented using 208 this method, e.g., "finish breakpoints" in Python. */ 209 enum ext_lang_bp_stop (*breakpoint_cond_says_stop) 210 (const struct extension_language_defn *, struct breakpoint *); 211 212 /* The next two are used to connect GDB's SIGINT handling with the 213 extension language's. 214 215 Terminology: If an extension language can use GDB's SIGINT handling then 216 we say the extension language has "cooperative SIGINT handling". 217 Python is an example of this. 218 219 These need not be implemented, but if one of them is implemented 220 then they all must be. */ 221 222 /* Set the SIGINT indicator. 223 This is called by GDB's SIGINT handler and must be async-safe. */ 224 void (*set_quit_flag) (const struct extension_language_defn *); 225 226 /* Return non-zero if a SIGINT has occurred. 227 This is expected to also clear the indicator. */ 228 int (*check_quit_flag) (const struct extension_language_defn *); 229 230 /* Called before gdb prints its prompt, giving extension languages an 231 opportunity to change it with set_prompt. 232 Returns EXT_LANG_RC_OK if the prompt was changed, EXT_LANG_RC_NOP if 233 the prompt was not changed, and EXT_LANG_RC_ERROR if an error was 234 encountered. 235 Extension languages are called in order, and once the prompt is 236 changed or an error occurs no further languages are called. */ 237 enum ext_lang_rc (*before_prompt) (const struct extension_language_defn *, 238 const char *current_gdb_prompt); 239 240 /* Return a vector of matching xmethod workers defined in this 241 extension language. The workers service methods with name 242 METHOD_NAME on objects of type OBJ_TYPE. The vector is returned 243 in DM_VEC. 244 245 This field may be NULL if the extension language does not support 246 xmethods. */ 247 enum ext_lang_rc (*get_matching_xmethod_workers) 248 (const struct extension_language_defn *extlang, 249 struct type *obj_type, 250 const char *method_name, 251 std::vector<xmethod_worker_up> *dm_vec); 252 253 /* Colorize a source file. NAME is the source file's name, and 254 CONTENTS is the contents of the file. This should either return 255 colorized (using ANSI terminal escapes) version of the contents, 256 or an empty option. */ 257 gdb::optional<std::string> (*colorize) (const std::string &name, 258 const std::string &contents); 259 }; 260 261 /* State necessary to restore a signal handler to its previous value. */ 262 263 struct signal_handler 264 { 265 /* Non-zero if "handler" has been set. */ 266 int handler_saved; 267 268 /* The signal handler. */ 269 sighandler_t handler; 270 }; 271 272 /* State necessary to restore the currently active extension language 273 to its previous value. */ 274 275 struct active_ext_lang_state 276 { 277 /* The previously active extension language. */ 278 const struct extension_language_defn *ext_lang; 279 280 /* Its SIGINT handler. */ 281 struct signal_handler sigint_handler; 282 }; 283 284 extern const struct extension_language_defn *get_active_ext_lang (void); 285 286 extern struct active_ext_lang_state *set_active_ext_lang 287 (const struct extension_language_defn *); 288 289 extern void restore_active_ext_lang (struct active_ext_lang_state *previous); 290 291 #endif /* EXTENSION_PRIV_H */ 292