1 /* Private implementation details of interface between gdb and its
4 Copyright (C) 2014-2018 Free Software Foundation, Inc.
6 This file is part of GDB.
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.
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.
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/>. */
21 #ifndef EXTENSION_PRIV_H
22 #define EXTENSION_PRIV_H
24 #include "extension.h"
26 #include "cli/cli-script.h"
28 /* The return code for some API calls. */
32 /* The operation completed successfully. */
35 /* The operation was not performed (e.g., no pretty-printer). */
38 /* There was an error (e.g., Python error while printing a value).
39 When an error occurs no further extension languages are tried.
40 This is to preserve existing behaviour, and because it's convenient
41 for Python developers.
42 Note: This is different than encountering a memory error trying to read
43 a value for pretty-printing. Here we're referring to, e.g., programming
44 errors that trigger an exception in the extension language. */
48 /* High level description of an extension/scripting language.
49 An entry for each is compiled into GDB regardless of whether the support
50 is present. This is done so that we can issue meaningful errors if the
51 support is not compiled in. */
53 struct extension_language_defn
55 /* Enum of the extension language. */
56 enum extension_language language;
58 /* The name of the extension language, lowercase. E.g., python. */
61 /* The capitalized name of the extension language.
62 For python this is "Python". For gdb this is "GDB". */
63 const char *capitalized_name;
65 /* The file suffix of this extension language. E.g., ".py". */
68 /* The suffix of per-objfile scripts to auto-load.
69 E.g., When the program loads libfoo.so, look for libfoo.so-gdb.py. */
70 const char *auto_load_suffix;
72 /* We support embedding external extension language code in GDB's own
73 scripting language. We do this by having a special command that begins
74 the extension language snippet, and terminate it with "end".
75 This specifies the control type used to implement this. */
76 enum command_control_type cli_control_type;
78 /* A pointer to the "methods" to load scripts in this language,
79 or NULL if the support is not compiled into GDB. */
80 const struct extension_language_script_ops *script_ops;
82 /* Either a pointer to the "methods" of the extension language interface
83 or NULL if the support is not compiled into GDB.
84 This is also NULL for GDB's own scripting language which is relatively
85 primitive, and doesn't provide these features. */
86 const struct extension_language_ops *ops;
89 /* The interface for loading scripts from external extension languages,
90 as well as GDB's own scripting language.
91 All of these methods are required to be implemented.
93 By convention all of these functions take a pseudo-this parameter
94 as the first argument. */
96 struct extension_language_script_ops
98 /* Load a script. This is called, e.g., via the "source" command.
99 If there's an error while processing the script this function may,
100 but is not required to, throw an error. */
101 script_sourcer_func *script_sourcer;
103 /* Load a script attached to an objfile.
104 If there's an error while processing the script this function may,
105 but is not required to, throw an error. */
106 objfile_script_sourcer_func *objfile_script_sourcer;
108 /* Execute a script attached to an objfile.
109 If there's an error while processing the script this function may,
110 but is not required to, throw an error. */
111 objfile_script_executor_func *objfile_script_executor;
113 /* Return non-zero if auto-loading scripts in this extension language
115 int (*auto_load_enabled) (const struct extension_language_defn *);
118 /* The interface for making calls from GDB to an external extension
119 language. This is for non-script-loading related functionality, like
120 pretty-printing, etc. The reason these are separated out is GDB's own
121 scripting language makes use of extension_language_script_opts, but it
122 makes no use of these. There is no (current) intention to split
123 extension_language_ops up any further.
124 All of these methods are optional and may be NULL, except where
127 By convention all of these functions take a pseudo-this parameter
128 as the first argument. */
130 struct extension_language_ops
132 /* Called at the end of gdb initialization to give the extension language
133 an opportunity to finish up. This is useful for things like adding
134 new commands where one has to wait until gdb itself is initialized. */
135 void (*finish_initialization) (const struct extension_language_defn *);
137 /* Return non-zero if the extension language successfully initialized.
138 This method is required. */
139 int (*initialized) (const struct extension_language_defn *);
141 /* Process a sequence of commands embedded in GDB's own scripting language.
146 void (*eval_from_control_command) (const struct extension_language_defn *,
147 struct command_line *);
149 /* Type-printing support:
150 start_type_printers, apply_type_printers, free_type_printers.
151 These methods are optional and may be NULL, but if one of them is
152 implemented then they all must be. */
154 /* Called before printing a type. */
155 void (*start_type_printers) (const struct extension_language_defn *,
156 struct ext_lang_type_printers *);
158 /* Try to pretty-print TYPE. If successful the pretty-printed type is
159 stored in *PRETTIED_TYPE, and the caller must free it.
160 Returns EXT_LANG_RC_OK upon success, EXT_LANG_RC_NOP if the type
161 is not recognized, and EXT_LANG_RC_ERROR if an error was encountered.
162 This function has a bit of a funny name, since it actually applies
163 recognizers, but this seemed clearer given the start_type_printers
164 and free_type_printers functions. */
165 enum ext_lang_rc (*apply_type_printers)
166 (const struct extension_language_defn *,
167 const struct ext_lang_type_printers *,
168 struct type *, char **prettied_type);
170 /* Called after a type has been printed to give the type pretty-printer
171 mechanism an opportunity to clean up. */
172 void (*free_type_printers) (const struct extension_language_defn *,
173 struct ext_lang_type_printers *);
175 /* Try to pretty-print a value of type TYPE located at VAL's contents
176 buffer + EMBEDDED_OFFSET, which came from the inferior at address
177 ADDRESS + EMBEDDED_OFFSET, onto stdio stream STREAM according to
179 VAL is the whole object that came from ADDRESS.
180 Returns EXT_LANG_RC_OK upon success, EXT_LANG_RC_NOP if the value
181 is not recognized, and EXT_LANG_RC_ERROR if an error was encountered. */
182 enum ext_lang_rc (*apply_val_pretty_printer)
183 (const struct extension_language_defn *,
185 LONGEST embedded_offset, CORE_ADDR address,
186 struct ui_file *stream, int recurse,
187 struct value *val, const struct value_print_options *options,
188 const struct language_defn *language);
190 /* GDB access to the "frame filter" feature.
191 FRAME is the source frame to start frame-filter invocation. FLAGS is an
192 integer holding the flags for printing. The following elements of
193 the FRAME_FILTER_FLAGS enum denotes the make-up of FLAGS:
194 PRINT_LEVEL is a flag indicating whether to print the frame's
195 relative level in the output. PRINT_FRAME_INFO is a flag that
196 indicates whether this function should print the frame
197 information, PRINT_ARGS is a flag that indicates whether to print
198 frame arguments, and PRINT_LOCALS, likewise, with frame local
199 variables. ARGS_TYPE is an enumerator describing the argument
200 format, OUT is the output stream to print. FRAME_LOW is the
201 beginning of the slice of frames to print, and FRAME_HIGH is the
202 upper limit of the frames to count. Returns SCR_BT_ERROR on error,
203 or SCR_BT_COMPLETED on success. */
204 enum ext_lang_bt_status (*apply_frame_filter)
205 (const struct extension_language_defn *,
206 struct frame_info *frame, int flags, enum ext_lang_frame_args args_type,
207 struct ui_out *out, int frame_low, int frame_high);
209 /* Update values held by the extension language when OBJFILE is discarded.
210 New global types must be created for every such value, which must then be
211 updated to use the new types.
212 This function typically just iterates over all appropriate values and
213 calls preserve_one_value for each one.
214 COPIED_TYPES is used to prevent cycles / duplicates and is passed to
215 preserve_one_value. */
216 void (*preserve_values) (const struct extension_language_defn *,
217 struct objfile *objfile, htab_t copied_types);
219 /* Return non-zero if there is a stop condition for the breakpoint.
220 This is used to implement the restriction that a breakpoint may have
221 at most one condition. */
222 int (*breakpoint_has_cond) (const struct extension_language_defn *,
223 struct breakpoint *);
225 /* Return a value of enum ext_lang_bp_stop indicating if there is a stop
226 condition for the breakpoint, and if so whether the program should
227 stop. This is called when the program has stopped at the specified
229 While breakpoints can have at most one condition, this is called for
230 every extension language, even if another extension language has a
231 "stop" method: other kinds of breakpoints may be implemented using
232 this method, e.g., "finish breakpoints" in Python. */
233 enum ext_lang_bp_stop (*breakpoint_cond_says_stop)
234 (const struct extension_language_defn *, struct breakpoint *);
236 /* The next two are used to connect GDB's SIGINT handling with the
237 extension language's.
239 Terminology: If an extension language can use GDB's SIGINT handling then
240 we say the extension language has "cooperative SIGINT handling".
241 Python is an example of this.
243 These need not be implemented, but if one of them is implemented
244 then they all must be. */
246 /* Set the SIGINT indicator.
247 This is called by GDB's SIGINT handler and must be async-safe. */
248 void (*set_quit_flag) (const struct extension_language_defn *);
250 /* Return non-zero if a SIGINT has occurred.
251 This is expected to also clear the indicator. */
252 int (*check_quit_flag) (const struct extension_language_defn *);
254 /* Called before gdb prints its prompt, giving extension languages an
255 opportunity to change it with set_prompt.
256 Returns EXT_LANG_RC_OK if the prompt was changed, EXT_LANG_RC_NOP if
257 the prompt was not changed, and EXT_LANG_RC_ERROR if an error was
259 Extension languages are called in order, and once the prompt is
260 changed or an error occurs no further languages are called. */
261 enum ext_lang_rc (*before_prompt) (const struct extension_language_defn *,
262 const char *current_gdb_prompt);
265 clone_xmethod_worker_data, free_xmethod_worker_data,
266 get_matching_xmethod_workers, get_xmethod_arg_types,
267 get_xmethod_return_type, invoke_xmethod.
268 These methods are optional and may be NULL, but if one of them is
269 implemented then they all must be. */
271 /* Clone DATA and return a new but identical xmethod worker data
272 object for this extension language. */
273 void * (*clone_xmethod_worker_data)
274 (const struct extension_language_defn *extlang, void *data);
276 /* Free the DATA object of this extension language. */
277 void (*free_xmethod_worker_data)
278 (const struct extension_language_defn *extlang, void *data);
280 /* Return a vector of matching xmethod workers defined in this
281 extension language. The workers service methods with name
282 METHOD_NAME on objects of type OBJ_TYPE. The vector is returned
284 enum ext_lang_rc (*get_matching_xmethod_workers)
285 (const struct extension_language_defn *extlang,
286 struct type *obj_type,
287 const char *method_name,
288 xmethod_worker_vec **dm_vec);
290 /* Given a WORKER servicing a particular method, return the types
291 of the arguments the method takes. The number of arguments is
292 returned in NARGS, and their types are returned in the array
294 enum ext_lang_rc (*get_xmethod_arg_types)
295 (const struct extension_language_defn *extlang,
296 struct xmethod_worker *worker,
298 struct type ***arg_types);
300 /* Given a WORKER servicing a particular method, fetch the type of the
301 result of the method. OBJECT, ARGS, NARGS are the same as for
302 invoke_xmethod. The result type is stored in *RESULT_TYPE.
303 For backward compatibility with 7.9, which did not support getting the
304 result type, if the get_result_type operation is not provided by WORKER
305 then EXT_LANG_RC_OK is returned and NULL is returned in *RESULT_TYPE. */
306 enum ext_lang_rc (*get_xmethod_result_type)
307 (const struct extension_language_defn *extlang,
308 struct xmethod_worker *worker,
309 struct value *object, struct value **args, int nargs,
310 struct type **result_type);
312 /* Invoke the xmethod serviced by WORKER. The xmethod is invoked
313 on OBJECT with arguments in the array ARGS. NARGS is the length of
314 this array. Returns the value returned by the xmethod. */
315 struct value * (*invoke_xmethod)
316 (const struct extension_language_defn *extlang,
317 struct xmethod_worker *worker,
318 struct value *object,
323 /* State necessary to restore a signal handler to its previous value. */
325 struct signal_handler
327 /* Non-zero if "handler" has been set. */
330 /* The signal handler. */
331 sighandler_t handler;
334 /* State necessary to restore the currently active extension language
335 to its previous value. */
337 struct active_ext_lang_state
339 /* The previously active extension language. */
340 const struct extension_language_defn *ext_lang;
342 /* Its SIGINT handler. */
343 struct signal_handler sigint_handler;
346 extern const struct extension_language_defn *get_active_ext_lang (void);
348 extern struct active_ext_lang_state *set_active_ext_lang
349 (const struct extension_language_defn *);
351 extern void restore_active_ext_lang (struct active_ext_lang_state *previous);
353 #endif /* EXTENSION_PRIV_H */