Commit | Line | Data |
---|---|---|
ed3ef339 DE |
1 | @c Copyright (C) 2008-2014 Free Software Foundation, Inc. |
2 | @c Permission is granted to copy, distribute and/or modify this document | |
3 | @c under the terms of the GNU Free Documentation License, Version 1.3 or | |
4 | @c any later version published by the Free Software Foundation; with the | |
5 | @c Invariant Sections being ``Free Software'' and ``Free Software Needs | |
6 | @c Free Documentation'', with the Front-Cover Texts being ``A GNU Manual,'' | |
7 | @c and with the Back-Cover Texts as in (a) below. | |
8 | @c | |
9 | @c (a) The FSF's Back-Cover Text is: ``You are free to copy and modify | |
10 | @c this GNU Manual. Buying copies from GNU Press supports the FSF in | |
11 | @c developing GNU and promoting software freedom.'' | |
12 | ||
13 | @node Guile | |
14 | @section Extending @value{GDBN} using Guile | |
15 | @cindex guile scripting | |
16 | @cindex scripting with guile | |
17 | ||
18 | You can extend @value{GDBN} using the @uref{http://www.gnu.org/software/guile/, | |
19 | Guile implementation of the Scheme programming language}. | |
20 | This feature is available only if @value{GDBN} was configured using | |
21 | @option{--with-guile}. | |
22 | ||
23 | @menu | |
24 | * Guile Introduction:: Introduction to Guile scripting in @value{GDBN} | |
25 | * Guile Commands:: Accessing Guile from @value{GDBN} | |
26 | * Guile API:: Accessing @value{GDBN} from Guile | |
27 | * Guile Auto-loading:: Automatically loading Guile code | |
28 | * Guile Modules:: Guile modules provided by @value{GDBN} | |
29 | @end menu | |
30 | ||
31 | @node Guile Introduction | |
32 | @subsection Guile Introduction | |
33 | ||
34 | Guile is an implementation of the Scheme programming language | |
35 | and is the GNU project's official extension language. | |
36 | ||
37 | Guile support in @value{GDBN} follows the Python support in @value{GDBN} | |
38 | reasonably closely, so concepts there should carry over. | |
39 | However, some things are done differently where it makes sense. | |
40 | ||
41 | @value{GDBN} requires Guile version 2.0 or greater. | |
42 | Older versions are not supported. | |
43 | ||
44 | @cindex guile scripts directory | |
45 | Guile scripts used by @value{GDBN} should be installed in | |
46 | @file{@var{data-directory}/guile}, where @var{data-directory} is | |
47 | the data directory as determined at @value{GDBN} startup (@pxref{Data Files}). | |
48 | This directory, known as the @dfn{guile directory}, | |
49 | is automatically added to the Guile Search Path in order to allow | |
50 | the Guile interpreter to locate all scripts installed at this location. | |
51 | ||
52 | @node Guile Commands | |
53 | @subsection Guile Commands | |
54 | @cindex guile commands | |
55 | @cindex commands to access guile | |
56 | ||
57 | @value{GDBN} provides two commands for accessing the Guile interpreter: | |
58 | ||
59 | @table @code | |
60 | @kindex guile-repl | |
61 | @kindex gr | |
62 | @item guile-repl | |
63 | @itemx gr | |
64 | The @code{guile-repl} command can be used to start an interactive | |
65 | Guile prompt or @dfn{repl}. To return to @value{GDBN}, | |
66 | type @kbd{,q} or the @code{EOF} character (e.g., @kbd{Ctrl-D} on | |
67 | an empty prompt). These commands do not take any arguments. | |
68 | ||
69 | @kindex guile | |
70 | @kindex gu | |
71 | @item guile @r{[}@var{scheme-expression}@r{]} | |
72 | @itemx gu @r{[}@var{scheme-expression}@r{]} | |
73 | The @code{guile} command can be used to evaluate a Scheme expression. | |
74 | ||
75 | If given an argument, @value{GDBN} will pass the argument to the Guile | |
76 | interpreter for evaluation. | |
77 | ||
78 | @smallexample | |
79 | (@value{GDBP}) guile (display (+ 20 3)) (newline) | |
80 | 23 | |
81 | @end smallexample | |
82 | ||
83 | The result of the Scheme expression is displayed using normal Guile rules. | |
84 | ||
85 | @smallexample | |
86 | (@value{GDBP}) guile (+ 20 3) | |
87 | 23 | |
88 | @end smallexample | |
89 | ||
90 | If you do not provide an argument to @code{guile}, it will act as a | |
91 | multi-line command, like @code{define}. In this case, the Guile | |
92 | script is made up of subsequent command lines, given after the | |
93 | @code{guile} command. This command list is terminated using a line | |
94 | containing @code{end}. For example: | |
95 | ||
96 | @smallexample | |
97 | (@value{GDBP}) guile | |
98 | >(display 23) | |
99 | >(newline) | |
100 | >end | |
101 | 23 | |
102 | @end smallexample | |
103 | @end table | |
104 | ||
105 | It is also possible to execute a Guile script from the @value{GDBN} | |
106 | interpreter: | |
107 | ||
108 | @table @code | |
109 | @item source @file{script-name} | |
110 | The script name must end with @samp{.scm} and @value{GDBN} must be configured | |
111 | to recognize the script language based on filename extension using | |
112 | the @code{script-extension} setting. @xref{Extending GDB, ,Extending GDB}. | |
113 | ||
114 | @item guile (load "script-name") | |
115 | This method uses the @code{load} Guile function. | |
116 | It takes a string argument that is the name of the script to load. | |
117 | See the Guile documentation for a description of this function. | |
118 | (@pxref{Loading,,, guile, GNU Guile Reference Manual}). | |
119 | @end table | |
120 | ||
121 | @node Guile API | |
122 | @subsection Guile API | |
123 | @cindex guile api | |
124 | @cindex programming in guile | |
125 | ||
126 | You can get quick online help for @value{GDBN}'s Guile API by issuing | |
127 | the command @w{@kbd{help guile}}, or by issuing the command @kbd{,help} | |
128 | from an interactive Guile session. Furthermore, most Guile procedures | |
129 | provided by @value{GDBN} have doc strings which can be obtained with | |
130 | @kbd{,describe @var{procedure-name}} or @kbd{,d @var{procedure-name}} | |
131 | from the Guile interactive prompt. | |
132 | ||
133 | @menu | |
134 | * Basic Guile:: Basic Guile Functions | |
135 | * Guile Configuration:: Guile configuration variables | |
136 | * GDB Scheme Data Types:: Scheme representations of GDB objects | |
137 | * Guile Exception Handling:: How Guile exceptions are translated | |
138 | * Values From Inferior In Guile:: Guile representation of values | |
139 | * Arithmetic In Guile:: Arithmetic in Guile | |
140 | * Types In Guile:: Guile representation of types | |
141 | * Guile Pretty Printing API:: Pretty-printing values with Guile | |
142 | * Selecting Guile Pretty-Printers:: How GDB chooses a pretty-printer | |
143 | * Writing a Guile Pretty-Printer:: Writing a pretty-printer | |
144 | * Objfiles In Guile:: Object files in Guile | |
145 | * Frames In Guile:: Accessing inferior stack frames from Guile | |
146 | * Blocks In Guile:: Accessing blocks from Guile | |
147 | * Symbols In Guile:: Guile representation of symbols | |
148 | * Symbol Tables In Guile:: Guile representation of symbol tables | |
149 | * Breakpoints In Guile:: Manipulating breakpoints using Guile | |
150 | * Lazy Strings In Guile:: Guile representation of lazy strings | |
151 | * Architectures In Guile:: Guile representation of architectures | |
152 | * Disassembly In Guile:: Disassembling instructions from Guile | |
153 | * I/O Ports in Guile:: GDB I/O ports | |
154 | * Memory Ports in Guile:: Accessing memory through ports and bytevectors | |
155 | * Iterators In Guile:: Basic iterator support | |
156 | @end menu | |
157 | ||
158 | @node Basic Guile | |
159 | @subsubsection Basic Guile | |
160 | ||
161 | @cindex guile stdout | |
162 | @cindex guile pagination | |
163 | At startup, @value{GDBN} overrides Guile's @code{current-output-port} and | |
164 | @code{current-error-port} to print using @value{GDBN}'s output-paging streams. | |
165 | A Guile program which outputs to one of these streams may have its | |
166 | output interrupted by the user (@pxref{Screen Size}). In this | |
167 | situation, a Guile @code{signal} exception is thrown with value @code{SIGINT}. | |
168 | ||
169 | Guile's history mechanism uses the same naming as @value{GDBN}'s, | |
170 | namely the user of dollar-variables (e.g., $1, $2, etc.). | |
171 | The results of evaluations in Guile and in GDB are counted separately, | |
172 | @code{$1} in Guile is not the same value as @code{$1} in @value{GDBN}. | |
173 | ||
174 | @value{GDBN} is not thread-safe. If your Guile program uses multiple | |
175 | threads, you must be careful to only call @value{GDBN}-specific | |
176 | functions in the @value{GDBN} thread. | |
177 | ||
178 | Some care must be taken when writing Guile code to run in | |
179 | @value{GDBN}. Two things are worth noting in particular: | |
180 | ||
181 | @itemize @bullet | |
182 | @item | |
183 | @value{GDBN} installs handlers for @code{SIGCHLD} and @code{SIGINT}. | |
184 | Guile code must not override these, or even change the options using | |
185 | @code{sigaction}. If your program changes the handling of these | |
186 | signals, @value{GDBN} will most likely stop working correctly. Note | |
187 | that it is unfortunately common for GUI toolkits to install a | |
188 | @code{SIGCHLD} handler. | |
189 | ||
190 | @item | |
191 | @value{GDBN} takes care to mark its internal file descriptors as | |
192 | close-on-exec. However, this cannot be done in a thread-safe way on | |
193 | all platforms. Your Guile programs should be aware of this and | |
194 | should both create new file descriptors with the close-on-exec flag | |
195 | set and arrange to close unneeded file descriptors before starting a | |
196 | child process. | |
197 | @end itemize | |
198 | ||
199 | @cindex guile gdb module | |
200 | @value{GDBN} introduces a new Guile module, named @code{gdb}. All | |
201 | methods and classes added by @value{GDBN} are placed in this module. | |
202 | @value{GDBN} does not automatically @code{import} the @code{gdb} module, | |
203 | scripts must do this themselves. There are various options for how to | |
204 | import a module, so @value{GDBN} leaves the choice of how the @code{gdb} | |
205 | module is imported to the user. | |
206 | To simplify interactive use, it is recommended to add one of the following | |
207 | to your ~/.gdbinit. | |
208 | ||
209 | @smallexample | |
210 | guile (use-modules (gdb)) | |
211 | @end smallexample | |
212 | ||
213 | @smallexample | |
214 | guile (use-modules ((gdb) #:renamer (symbol-prefix-proc 'gdb:))) | |
215 | @end smallexample | |
216 | ||
217 | Which one to choose depends on your preference. | |
218 | The second one adds @code{gdb:} as a prefix to all module functions | |
219 | and variables. | |
220 | ||
221 | The rest of this manual assumes the @code{gdb} module has been imported | |
222 | without any prefix. See the Guile documentation for @code{use-modules} | |
223 | for more information | |
224 | (@pxref{Using Guile Modules,,, guile, GNU Guile Reference Manual}). | |
225 | ||
226 | Example: | |
227 | ||
228 | @smallexample | |
229 | (gdb) guile (value-type (make-value 1)) | |
230 | ERROR: Unbound variable: value-type | |
231 | Error while executing Scheme code. | |
232 | (gdb) guile (use-modules (gdb)) | |
233 | (gdb) guile (value-type (make-value 1)) | |
234 | int | |
235 | (gdb) | |
236 | @end smallexample | |
237 | ||
238 | The @code{(gdb)} module provides these basic Guile functions. | |
239 | ||
240 | @c TODO: line length | |
241 | @deffn {Scheme Procedure} execute command @r{[}#:from-tty boolean@r{]}@r{[}#:to-string boolean@r{]} | |
242 | Evaluate @var{command}, a string, as a @value{GDBN} CLI command. | |
243 | If a @value{GDBN} exception happens while @var{command} runs, it is | |
244 | translated as described in | |
245 | @ref{Guile Exception Handling,,Guile Exception Handling}. | |
246 | ||
247 | @var{from-tty} specifies whether @value{GDBN} ought to consider this | |
248 | command as having originated from the user invoking it interactively. | |
249 | It must be a boolean value. If omitted, it defaults to @code{#f}. | |
250 | ||
251 | By default, any output produced by @var{command} is sent to | |
252 | @value{GDBN}'s standard output (and to the log output if logging is | |
253 | turned on). If the @var{to-string} parameter is | |
254 | @code{#t}, then output will be collected by @code{gdb.execute} and | |
255 | returned as a string. The default is @code{#f}, in which case the | |
256 | return value is unspecified. If @var{to-string} is @code{#t}, the | |
257 | @value{GDBN} virtual terminal will be temporarily set to unlimited width | |
258 | and height, and its pagination will be disabled; @pxref{Screen Size}. | |
259 | @end deffn | |
260 | ||
261 | @deffn {Scheme Procedure} history-ref number | |
262 | Return a value from @value{GDBN}'s value history (@pxref{Value | |
263 | History}). @var{number} indicates which history element to return. | |
264 | If @var{number} is negative, then @value{GDBN} will take its absolute value | |
265 | and count backward from the last element (i.e., the most recent element) to | |
266 | find the value to return. If @var{number} is zero, then @value{GDBN} will | |
267 | return the most recent element. If the element specified by @var{number} | |
268 | doesn't exist in the value history, a @code{gdb:error} exception will be | |
269 | raised. | |
270 | ||
271 | If no exception is raised, the return value is always an instance of | |
272 | @code{<gdb:value>} (@pxref{Values From Inferior In Guile}). | |
273 | ||
274 | @emph{Note:} @value{GDBN}'s value history is independent of Guile's. | |
275 | @code{$1} in @value{GDBN}'s value history contains the result of evaluating | |
276 | an expression from @value{GDBN}'s command line and @code{$1} from Guile's | |
277 | history contains the result of evaluating an expression from Guile's | |
278 | command line. | |
279 | @end deffn | |
280 | ||
281 | @deffn {Scheme Procedure} parse-and-eval expression | |
282 | Parse @var{expression} as an expression in the current language, | |
283 | evaluate it, and return the result as a @code{<gdb:value>}. | |
284 | @var{expression} must be a string. | |
285 | ||
286 | This function is useful when computing values. | |
287 | For example, it is the only way to get the value of a | |
288 | convenience variable (@pxref{Convenience Vars}) as a @code{<gdb:value>}. | |
289 | @end deffn | |
290 | ||
291 | @deffn {Scheme Procedure} string->argv string | |
292 | Convert a string to a list of strings split up according to | |
293 | @value{GDBN}'s argv parsing rules. | |
294 | @end deffn | |
295 | ||
296 | @node Guile Configuration | |
297 | @subsubsection Guile Configuration | |
298 | @cindex guile configuration | |
299 | ||
300 | @value{GDBN} provides these Scheme functions to access various configuration | |
301 | parameters. | |
302 | ||
303 | @deffn {Scheme Procedure} data-directory | |
304 | Return a string containing @value{GDBN}'s data directory. | |
305 | This directory contains @value{GDBN}'s ancillary files, including | |
306 | the Guile modules provided by @value{GDBN}. | |
307 | @end deffn | |
308 | ||
309 | @deffn {Scheme Procedure} gdb-version | |
310 | Return a string containing the @value{GDBN} version. | |
311 | @end deffn | |
312 | ||
313 | @deffn {Scheme Procedure} host-config | |
314 | Return a string containing the host configuration. | |
315 | This is the string passed to @code{--host} when @value{GDBN} was configured. | |
316 | @end deffn | |
317 | ||
318 | @deffn {Scheme Procedure} target-config | |
319 | Return a string containing the target configuration. | |
320 | This is the string passed to @code{--target} when @value{GDBN} was configured. | |
321 | @end deffn | |
322 | ||
323 | @node GDB Scheme Data Types | |
324 | @subsubsection GDB Scheme Data Types | |
325 | @cindex gdb smobs | |
326 | ||
327 | @value{GDBN} uses Guile's @dfn{smob} (small object) | |
328 | data type for all @value{GDBN} objects | |
329 | (@pxref{Defining New Types (Smobs),,, guile, GNU Guile Reference Manual}). | |
330 | The smobs that @value{GDBN} provides are called @dfn{gsmobs}. | |
331 | ||
332 | @deffn {Scheme Procedure} gsmob-kind gsmob | |
333 | Return the kind of the gsmob, e.g., @code{<gdb:breakpoint>}, | |
334 | as a symbol. | |
335 | @end deffn | |
336 | ||
337 | Every @code{gsmob} provides a common set of functions for extending | |
338 | them in simple ways. Each @code{gsmob} has a list of properties, | |
339 | initially empty. These properties are akin to Guile's object properties, | |
340 | but are stored with the @code{gsmob} | |
341 | (@pxref{Object Properties,,, guile, GNU Guile Reference Manual}). | |
342 | Property names can be any @code{eq?}-able value, but it is recommended | |
343 | that they be symbols. | |
344 | ||
345 | @deffn {Scheme Procedure} set-gsmob-property! gsmob property-name value | |
346 | Set the value of property @code{property-name} to value @code{value}. | |
347 | The result is unspecified. | |
348 | @end deffn | |
349 | ||
350 | @deffn {Scheme Procedure} gsmob-property gsmob property-name | |
351 | Return the value of property @code{property-name}. | |
352 | If the property isn't present then @code{#f} is returned. | |
353 | @end deffn | |
354 | ||
355 | @deffn {Scheme Procedure} gsmob-has-property? gsmob property-name | |
356 | Return @code{#t} if @code{gsmob} has property @code{property-name}. | |
357 | Otherwise return @code{#f}. | |
358 | @end deffn | |
359 | ||
360 | @deffn {Scheme Procedure} gsmob-properties gsmob | |
361 | Return an unsorted list of names of properties. | |
362 | @end deffn | |
363 | ||
364 | @value{GDBN} defines the following Scheme smobs: | |
365 | ||
366 | @table @code | |
367 | @item <gdb:arch> | |
368 | @xref{Architectures In Guile}. | |
369 | ||
370 | @item <gdb:block> | |
371 | @xref{Blocks In Guile}. | |
372 | ||
373 | @item <gdb:block-symbols-iterator> | |
374 | @xref{Blocks In Guile}. | |
375 | ||
376 | @item <gdb:breakpoint> | |
377 | @xref{Breakpoints In Guile}. | |
378 | ||
379 | @item <gdb:exception> | |
380 | @xref{Guile Exception Handling}. | |
381 | ||
382 | @item <gdb:frame> | |
383 | @xref{Frames In Guile}. | |
384 | ||
385 | @item <gdb:iterator> | |
386 | @xref{Iterators In Guile}. | |
387 | ||
388 | @item <gdb:lazy-string> | |
389 | @xref{Lazy Strings In Guile}. | |
390 | ||
391 | @item <gdb:objfile> | |
392 | @xref{Objfiles In Guile}. | |
393 | ||
394 | @item <gdb:pretty-printer> | |
395 | @xref{Guile Pretty Printing API}. | |
396 | ||
397 | @item <gdb:pretty-printer-worker> | |
398 | @xref{Guile Pretty Printing API}. | |
399 | ||
400 | @item <gdb:symbol> | |
401 | @xref{Symbols In Guile}. | |
402 | ||
403 | @item <gdb:symtab> | |
404 | @xref{Symbol Tables In Guile}. | |
405 | ||
406 | @item <gdb:sal> | |
407 | @xref{Symbol Tables In Guile}. | |
408 | ||
409 | @item <gdb:type> | |
410 | @xref{Types In Guile}. | |
411 | ||
412 | @item <gdb:field> | |
413 | @xref{Types In Guile}. | |
414 | ||
415 | @item <gdb:value> | |
416 | @xref{Values From Inferior In Guile}. | |
417 | @end table | |
418 | ||
419 | The following gsmobs are managed internally so that the Scheme function | |
420 | @code{eq?} may be applied to them. | |
421 | ||
422 | @table @code | |
423 | @item <gdb:arch> | |
424 | @item <gdb:block> | |
425 | @item <gdb:breakpoint> | |
426 | @item <gdb:frame> | |
427 | @item <gdb:objfile> | |
428 | @item <gdb:symbol> | |
429 | @item <gdb:symtab> | |
430 | @item <gdb:type> | |
431 | @end table | |
432 | ||
433 | @node Guile Exception Handling | |
434 | @subsubsection Guile Exception Handling | |
435 | @cindex guile exceptions | |
436 | @cindex exceptions, guile | |
437 | @kindex set guile print-stack | |
438 | ||
439 | When executing the @code{guile} command, Guile exceptions | |
440 | uncaught within the Guile code are translated to calls to the | |
441 | @value{GDBN} error-reporting mechanism. If the command that called | |
442 | @code{guile} does not handle the error, @value{GDBN} will | |
443 | terminate it and report the error according to the setting of | |
444 | the @code{guile print-stack} parameter. | |
445 | ||
446 | The @code{guile print-stack} parameter has three settings: | |
447 | ||
448 | @table @code | |
449 | @item none | |
450 | Nothing is printed. | |
451 | ||
452 | @item message | |
453 | An error message is printed containing the Guile exception name, | |
454 | the associated value, and the Guile call stack backtrace at the | |
455 | point where the exception was raised. Example: | |
456 | ||
457 | @smallexample | |
458 | (@value{GDBP}) guile (display foo) | |
459 | ERROR: In procedure memoize-variable-access!: | |
460 | ERROR: Unbound variable: foo | |
461 | Error while executing Scheme code. | |
462 | @end smallexample | |
463 | ||
464 | @item full | |
465 | In addition to an error message a full backtrace is printed. | |
466 | ||
467 | @smallexample | |
468 | (@value{GDBP}) set guile print-stack full | |
469 | (@value{GDBP}) guile (display foo) | |
470 | Guile Backtrace: | |
471 | In ice-9/boot-9.scm: | |
472 | 157: 10 [catch #t #<catch-closure 2c76e20> ...] | |
473 | In unknown file: | |
474 | ?: 9 [apply-smob/1 #<catch-closure 2c76e20>] | |
475 | In ice-9/boot-9.scm: | |
476 | 157: 8 [catch #t #<catch-closure 2c76d20> ...] | |
477 | In unknown file: | |
478 | ?: 7 [apply-smob/1 #<catch-closure 2c76d20>] | |
479 | ?: 6 [call-with-input-string "(display foo)" ...] | |
480 | In ice-9/boot-9.scm: | |
481 | 2320: 5 [save-module-excursion #<procedure 2c2dc30 ... ()>] | |
482 | In ice-9/eval-string.scm: | |
483 | 44: 4 [read-and-eval #<input: string 27cb410> #:lang ...] | |
484 | 37: 3 [lp (display foo)] | |
485 | In ice-9/eval.scm: | |
486 | 387: 2 [eval # ()] | |
487 | 393: 1 [eval #<memoized foo> ()] | |
488 | In unknown file: | |
489 | ?: 0 [memoize-variable-access! #<memoized foo> ...] | |
490 | ||
491 | ERROR: In procedure memoize-variable-access!: | |
492 | ERROR: Unbound variable: foo | |
493 | Error while executing Scheme code. | |
494 | @end smallexample | |
495 | @end table | |
496 | ||
497 | @value{GDBN} errors that happen in @value{GDBN} commands invoked by | |
498 | Guile code are converted to Guile exceptions. The type of the | |
499 | Guile exception depends on the error. | |
500 | ||
501 | Guile procedures provided by @value{GDBN} can throw the standard | |
502 | Guile exceptions like @code{wrong-type-arg} and @code{out-of-range}. | |
503 | ||
504 | User interrupt (via @kbd{C-c} or by typing @kbd{q} at a pagination | |
505 | prompt) is translated to a Guile @code{signal} exception with value | |
506 | @code{SIGINT}. | |
507 | ||
508 | @value{GDBN} Guile procedures can also throw these exceptions: | |
509 | ||
510 | @vtable @code | |
511 | @item gdb:error | |
512 | This exception is a catch-all for errors generated from within @value{GDBN}. | |
513 | ||
514 | @item gdb:invalid-object | |
515 | This exception is thrown when accessing Guile objects that wrap underlying | |
516 | @value{GDBN} objects have become invalid. For example, a | |
517 | @code{<gdb:breakpoint>} object becomes invalid if the user deletes it | |
518 | from the command line. The object still exists in Guile, but the | |
519 | object it represents is gone. Further operations on this breakpoint | |
520 | will throw this exception. | |
521 | ||
522 | @item gdb:memory-error | |
523 | This exception is thrown when an operation tried to access invalid | |
524 | memory in the inferior. | |
525 | ||
526 | @item gdb:pp-type-error | |
527 | This exception is thrown when a Guile pretty-printer passes a bad object | |
528 | to @value{GDBN}. | |
529 | @end vtable | |
530 | ||
531 | The following exception-related procedures are provided by the | |
532 | @code{(gdb)} module. | |
533 | ||
534 | @deffn {Scheme Procedure} make-exception key args | |
535 | Return a @code{<gdb:exception>} object. | |
536 | @var{key} and @var{args} are the standard Guile parameters of an exception. | |
537 | See the Guile documentation for more information | |
538 | (@pxref{Exceptions,,, guile, GNU Guile Reference Manual}). | |
539 | @end deffn | |
540 | ||
541 | @deffn {Scheme Procedure} exception? object | |
542 | Return @code{#t} if @var{object} is a @code{<gdb:exception>} object. | |
543 | Otherwise return @code{#f}. | |
544 | @end deffn | |
545 | ||
546 | @deffn {Scheme Procedure} exception-key exception | |
547 | Return the @var{args} field of a @code{<gdb:exception>} object. | |
548 | @end deffn | |
549 | ||
550 | @deffn {Scheme Procedure} exception-args exception | |
551 | Return the @var{args} field of a @code{<gdb:exception>} object. | |
552 | @end deffn | |
553 | ||
554 | @node Values From Inferior In Guile | |
555 | @subsubsection Values From Inferior In Guile | |
556 | @cindex values from inferior, in guile | |
557 | @cindex guile, working with values from inferior | |
558 | ||
559 | @tindex @code{<gdb:value>} | |
560 | @value{GDBN} provides values it obtains from the inferior program in | |
561 | an object of type @code{<gdb:value>}. @value{GDBN} uses this object | |
562 | for its internal bookkeeping of the inferior's values, and for | |
563 | fetching values when necessary. | |
564 | ||
565 | @value{GDBN} does not memoize @code{<gdb:value>} objects. | |
566 | @code{make-value} always returns a fresh object. | |
567 | ||
568 | @smallexample | |
569 | (gdb) guile (eq? (make-value 1) (make-value 1)) | |
570 | $1 = #f | |
571 | (gdb) guile (equal? (make-value 1) (make-value 1)) | |
572 | $1 = #t | |
573 | @end smallexample | |
574 | ||
575 | A @code{<gdb:value>} that represents a function can be executed via | |
576 | inferior function call with @code{value-call}. | |
577 | Any arguments provided to the call must match the function's prototype, | |
578 | and must be provided in the order specified by that prototype. | |
579 | ||
580 | For example, @code{some-val} is a @code{<gdb:value>} instance | |
581 | representing a function that takes two integers as arguments. To | |
582 | execute this function, call it like so: | |
583 | ||
584 | @smallexample | |
585 | (define result (value-call some-val 10 20)) | |
586 | @end smallexample | |
587 | ||
588 | Any values returned from a function call are @code{<gdb:value>} objects. | |
589 | ||
590 | Note: Unlike Python scripting in @value{GDBN}, | |
591 | inferior values that are simple scalars cannot be used directly in | |
592 | Scheme expressions that are valid for the value's data type. | |
593 | For example, @code{(+ (parse-and-eval "int_variable") 2)} does not work. | |
594 | And inferior values that are structures or instances of some class cannot | |
595 | be accessed using any special syntax, instead @code{value-field} must be used. | |
596 | ||
597 | The following value-related procedures are provided by the | |
598 | @code{(gdb)} module. | |
599 | ||
600 | @deffn {Scheme Procedure} value? object | |
601 | Return @code{#t} if @var{object} is a @code{<gdb:value>} object. | |
602 | Otherwise return @code{#f}. | |
603 | @end deffn | |
604 | ||
605 | @deffn {Scheme Procedure} make-value value @r{[}#:type type@r{]} | |
606 | Many Scheme values can be converted directly to a @code{<gdb:value>} | |
607 | with this procedure. If @var{type} is specified, the result is a value | |
608 | of this type, and if @var{value} can't be represented with this type | |
609 | an exception is thrown. Otherwise the type of the result is determined from | |
610 | @var{value} as described below. | |
611 | ||
612 | @xref{Architectures In Guile}, for a list of the builtin | |
613 | types for an architecture. | |
614 | ||
615 | Here's how Scheme values are converted when @var{type} argument to | |
616 | @code{make-value} is not specified: | |
617 | ||
618 | @table @asis | |
619 | @item Scheme boolean | |
620 | A Scheme boolean is converted the boolean type for the current language. | |
621 | ||
622 | @item Scheme integer | |
623 | A Scheme integer is converted to the first of a C @code{int}, | |
624 | @code{unsigned int}, @code{long}, @code{unsigned long}, | |
625 | @code{long long} or @code{unsigned long long} type | |
626 | for the current architecture that can represent the value. | |
627 | ||
628 | If the Scheme integer cannot be represented as a target integer | |
629 | an @code{out-of-range} exception is thrown. | |
630 | ||
631 | @item Scheme real | |
632 | A Scheme real is converted to the C @code{double} type for the | |
633 | current architecture. | |
634 | ||
635 | @item Scheme string | |
636 | A Scheme string is converted to a string in the current target | |
637 | language using the current target encoding. | |
638 | Characters that cannot be represented in the current target encoding | |
639 | are replaced with the corresponding escape sequence. This is Guile's | |
640 | @code{SCM_FAILED_CONVERSION_ESCAPE_SEQUENCE} conversion strategy | |
641 | (@pxref{Strings,,, guile, GNU Guile Reference Manual}). | |
642 | ||
643 | Passing @var{type} is not supported in this case, | |
644 | if it is provided a @code{wrong-type-arg} exception is thrown. | |
645 | ||
646 | @item @code{<gdb:lazy-string>} | |
647 | If @var{value} is a @code{<gdb:lazy-string>} object (@pxref{Lazy Strings In | |
648 | Guile}), then the @code{lazy-string->value} procedure is called, and | |
649 | its result is used. | |
650 | ||
651 | Passing @var{type} is not supported in this case, | |
652 | if it is provided a @code{wrong-type-arg} exception is thrown. | |
653 | ||
654 | @item Scheme bytevector | |
655 | If @var{value} is a Scheme bytevector and @var{type} is provided, | |
656 | @var{value} must be the same size, in bytes, of values of type @var{type}, | |
657 | and the result is essentially created by using @code{memcpy}. | |
658 | ||
659 | If @var{value} is a Scheme bytevector and @var{type} is not provided, | |
660 | the result is an array of type @code{uint8} of the same length. | |
661 | @end table | |
662 | @end deffn | |
663 | ||
664 | @cindex optimized out value in guile | |
665 | @deffn {Scheme Procedure} value-optimized-out? value | |
666 | Return @code{#t} if the compiler optimized out @var{value}, | |
667 | thus it is not available for fetching from the inferior. | |
668 | Otherwise return @code{#f}. | |
669 | @end deffn | |
670 | ||
671 | @deffn {Scheme Procedure} value-address value | |
672 | If @var{value} is addressable, returns a | |
673 | @code{<gdb:value>} object representing the address. | |
674 | Otherwise, @code{#f} is returned. | |
675 | @end deffn | |
676 | ||
677 | @deffn {Scheme Procedure} value-type value | |
678 | Return the type of @var{value} as a @code{<gdb:type>} object | |
679 | (@pxref{Types In Guile}). | |
680 | @end deffn | |
681 | ||
682 | @deffn {Scheme Procedure} value-dynamic-type value | |
683 | Return the dynamic type of @var{value}. This uses C@t{++} run-time | |
684 | type information (@acronym{RTTI}) to determine the dynamic type of the | |
685 | value. If the value is of class type, it will return the class in | |
686 | which the value is embedded, if any. If the value is of pointer or | |
687 | reference to a class type, it will compute the dynamic type of the | |
688 | referenced object, and return a pointer or reference to that type, | |
689 | respectively. In all other cases, it will return the value's static | |
690 | type. | |
691 | ||
692 | Note that this feature will only work when debugging a C@t{++} program | |
693 | that includes @acronym{RTTI} for the object in question. Otherwise, | |
694 | it will just return the static type of the value as in @kbd{ptype foo}. | |
695 | @xref{Symbols, ptype}. | |
696 | @end deffn | |
697 | ||
698 | @deffn {Scheme Procedure} value-cast value type | |
699 | Return a new instance of @code{<gdb:value>} that is the result of | |
700 | casting @var{value} to the type described by @var{type}, which must | |
701 | be a @code{<gdb:type>} object. If the cast cannot be performed for some | |
702 | reason, this method throws an exception. | |
703 | @end deffn | |
704 | ||
705 | @deffn {Scheme Procedure} value-dynamic-cast value type | |
706 | Like @code{value-cast}, but works as if the C@t{++} @code{dynamic_cast} | |
707 | operator were used. Consult a C@t{++} reference for details. | |
708 | @end deffn | |
709 | ||
710 | @deffn {Scheme Procedure} value-reinterpret-cast value type | |
711 | Like @code{value-cast}, but works as if the C@t{++} @code{reinterpret_cast} | |
712 | operator were used. Consult a C@t{++} reference for details. | |
713 | @end deffn | |
714 | ||
715 | @deffn {Scheme Procedure} value-dereference value | |
716 | For pointer data types, this method returns a new @code{<gdb:value>} object | |
717 | whose contents is the object pointed to by @var{value}. For example, if | |
718 | @code{foo} is a C pointer to an @code{int}, declared in your C program as | |
719 | ||
720 | @smallexample | |
721 | int *foo; | |
722 | @end smallexample | |
723 | ||
724 | @noindent | |
725 | then you can use the corresponding @code{<gdb:value>} to access what | |
726 | @code{foo} points to like this: | |
727 | ||
728 | @smallexample | |
729 | (define bar (value-dereference foo)) | |
730 | @end smallexample | |
731 | ||
732 | The result @code{bar} will be a @code{<gdb:value>} object holding the | |
733 | value pointed to by @code{foo}. | |
734 | ||
735 | A similar function @code{value-referenced-value} exists which also | |
736 | returns @code{<gdb:value>} objects corresonding to the values pointed to | |
737 | by pointer values (and additionally, values referenced by reference | |
738 | values). However, the behavior of @code{value-dereference} | |
739 | differs from @code{value-referenced-value} by the fact that the | |
740 | behavior of @code{value-dereference} is identical to applying the C | |
741 | unary operator @code{*} on a given value. For example, consider a | |
742 | reference to a pointer @code{ptrref}, declared in your C@t{++} program | |
743 | as | |
744 | ||
745 | @smallexample | |
746 | typedef int *intptr; | |
747 | ... | |
748 | int val = 10; | |
749 | intptr ptr = &val; | |
750 | intptr &ptrref = ptr; | |
751 | @end smallexample | |
752 | ||
753 | Though @code{ptrref} is a reference value, one can apply the method | |
754 | @code{value-dereference} to the @code{<gdb:value>} object corresponding | |
755 | to it and obtain a @code{<gdb:value>} which is identical to that | |
756 | corresponding to @code{val}. However, if you apply the method | |
757 | @code{value-referenced-value}, the result would be a @code{<gdb:value>} | |
758 | object identical to that corresponding to @code{ptr}. | |
759 | ||
760 | @smallexample | |
761 | (define scm-ptrref (parse-and-eval "ptrref")) | |
762 | (define scm-val (value-dereference scm-ptrref)) | |
763 | (define scm-ptr (value-referenced-value scm-ptrref)) | |
764 | @end smallexample | |
765 | ||
766 | The @code{<gdb:value>} object @code{scm-val} is identical to that | |
767 | corresponding to @code{val}, and @code{scm-ptr} is identical to that | |
768 | corresponding to @code{ptr}. In general, @code{value-dereference} can | |
769 | be applied whenever the C unary operator @code{*} can be applied | |
770 | to the corresponding C value. For those cases where applying both | |
771 | @code{value-dereference} and @code{value-referenced-value} is allowed, | |
772 | the results obtained need not be identical (as we have seen in the above | |
773 | example). The results are however identical when applied on | |
774 | @code{<gdb:value>} objects corresponding to pointers (@code{<gdb:value>} | |
775 | objects with type code @code{TYPE_CODE_PTR}) in a C/C@t{++} program. | |
776 | @end deffn | |
777 | ||
778 | @deffn {Scheme Procedure} value-referenced-value value | |
779 | For pointer or reference data types, this method returns a new | |
780 | @code{<gdb:value>} object corresponding to the value referenced by the | |
781 | pointer/reference value. For pointer data types, | |
782 | @code{value-dereference} and @code{value-referenced-value} produce | |
783 | identical results. The difference between these methods is that | |
784 | @code{value-dereference} cannot get the values referenced by reference | |
785 | values. For example, consider a reference to an @code{int}, declared | |
786 | in your C@t{++} program as | |
787 | ||
788 | @smallexample | |
789 | int val = 10; | |
790 | int &ref = val; | |
791 | @end smallexample | |
792 | ||
793 | @noindent | |
794 | then applying @code{value-dereference} to the @code{<gdb:value>} object | |
795 | corresponding to @code{ref} will result in an error, while applying | |
796 | @code{value-referenced-value} will result in a @code{<gdb:value>} object | |
797 | identical to that corresponding to @code{val}. | |
798 | ||
799 | @smallexample | |
800 | (define scm-ref (parse-and-eval "ref")) | |
801 | (define err-ref (value-dereference scm-ref)) ;; error | |
802 | (define scm-val (value-referenced-value scm-ref)) ;; ok | |
803 | @end smallexample | |
804 | ||
805 | The @code{<gdb:value>} object @code{scm-val} is identical to that | |
806 | corresponding to @code{val}. | |
807 | @end deffn | |
808 | ||
809 | @deffn {Scheme Procedure} value-field value field-name | |
810 | Return field @var{field-name} from @code{<gdb:value>} object @var{value}. | |
811 | @end deffn | |
812 | ||
813 | @deffn {Scheme Procedure} value-subscript value index | |
814 | Return the value of array @var{value} at index @var{index}. | |
815 | @var{value} must be a subscriptable @code{<gdb:value>} object. | |
816 | @end deffn | |
817 | ||
818 | @deffn {Scheme Procedure} value-call value arg-list | |
819 | Perform an inferior function call, taking @var{value} as a pointer | |
820 | to the function to call. | |
821 | Each element of list @var{arg-list} must be a <gdb:value> object or an object | |
822 | that can be converted to a value. | |
823 | The result is the value returned by the function. | |
824 | @end deffn | |
825 | ||
826 | @deffn {Scheme Procedure} value->bool value | |
827 | Return the Scheme boolean representing @code{<gdb:value>} @var{value}. | |
828 | The value must be ``integer like''. Pointers are ok. | |
829 | @end deffn | |
830 | ||
831 | @deffn {Scheme Procedure} value->integer | |
832 | Return the Scheme integer representing @code{<gdb:value>} @var{value}. | |
833 | The value must be ``integer like''. Pointers are ok. | |
834 | @end deffn | |
835 | ||
836 | @deffn {Scheme Procedure} value->real | |
837 | Return the Scheme real number representing @code{<gdb:value>} @var{value}. | |
838 | The value must be a number. | |
839 | @end deffn | |
840 | ||
841 | @deffn {Scheme Procedure} value->bytevector | |
842 | Return a Scheme bytevector with the raw contents of @code{<gdb:value>} | |
843 | @var{value}. No transformation, endian or otherwise, is performed. | |
844 | @end deffn | |
845 | ||
846 | @c TODO: line length | |
847 | @deffn {Scheme Procedure} value->string value @r{[}#:encoding encoding@r{]} @r{[}#:errors errors@r{]} @r{[}#:length length@r{]} | |
848 | If @var{value>} represents a string, then this method | |
849 | converts the contents to a Guile string. Otherwise, this method will | |
850 | throw an exception. | |
851 | ||
852 | Values are interpreted as strings according to the rules of the | |
853 | current language. If the optional length argument is given, the | |
854 | string will be converted to that length, and will include any embedded | |
855 | zeroes that the string may contain. Otherwise, for languages | |
856 | where the string is zero-terminated, the entire string will be | |
857 | converted. | |
858 | ||
859 | For example, in C-like languages, a value is a string if it is a pointer | |
860 | to or an array of characters or ints of type @code{wchar_t}, @code{char16_t}, | |
861 | or @code{char32_t}. | |
862 | ||
863 | If the optional @var{encoding} argument is given, it must be a string | |
864 | naming the encoding of the string in the @code{<gdb:value>}, such as | |
865 | @code{"ascii"}, @code{"iso-8859-6"} or @code{"utf-8"}. It accepts | |
866 | the same encodings as the corresponding argument to Guile's | |
867 | @code{scm_from_stringn} function, and the Guile codec machinery will be used | |
868 | to convert the string. If @var{encoding} is not given, or if | |
869 | @var{encoding} is the empty string, then either the @code{target-charset} | |
870 | (@pxref{Character Sets}) will be used, or a language-specific encoding | |
871 | will be used, if the current language is able to supply one. | |
872 | ||
873 | The optional @var{errors} argument is one of @code{#f}, @code{error} or | |
874 | @code{substitute}. @code{error} and @code{substitute} must be symbols. | |
875 | If @var{errors} is not specified, or if its value is @code{#f}, then the | |
876 | default conversion strategy is used, which is set with the Scheme function | |
877 | @code{set-port-conversion-strategy!}. | |
878 | If the value is @code{'error} then an exception is thrown if there is any | |
879 | conversion error. If the value is @code{'substitute} then any conversion | |
880 | error is replaced with question marks. | |
881 | @xref{Strings,,, guile, GNU Guile Reference Manual}. | |
882 | ||
883 | If the optional @var{length} argument is given, the string will be | |
884 | fetched and converted to the given length. | |
885 | The length must be a Scheme integer and not a @code{<gdb:value>} integer. | |
886 | @end deffn | |
887 | ||
888 | @c TODO: line length | |
6fb526ee | 889 | @deffn {Scheme Procedure} value->lazy-string value @r{[}#:encoding encoding@r{]} @r{[}#:length length@r{]} |
ed3ef339 DE |
890 | If this @code{<gdb:value>} represents a string, then this method |
891 | converts @var{value} to a @code{<gdb:lazy-string} (@pxref{Lazy Strings | |
892 | In Guile}). Otherwise, this method will throw an exception. | |
893 | ||
894 | If the optional @var{encoding} argument is given, it must be a string | |
895 | naming the encoding of the @code{<gdb:lazy-string}. Some examples are: | |
896 | @code{"ascii"}, @code{"iso-8859-6"} or @code{"utf-8"}. If the | |
897 | @var{encoding} argument is an encoding that @value{GDBN} does not | |
898 | recognize, @value{GDBN} will raise an error. | |
899 | ||
900 | When a lazy string is printed, the @value{GDBN} encoding machinery is | |
901 | used to convert the string during printing. If the optional | |
902 | @var{encoding} argument is not provided, or is an empty string, | |
903 | @value{GDBN} will automatically select the encoding most suitable for | |
904 | the string type. For further information on encoding in @value{GDBN} | |
905 | please see @ref{Character Sets}. | |
906 | ||
907 | If the optional @var{length} argument is given, the string will be | |
908 | fetched and encoded to the length of characters specified. If | |
909 | the @var{length} argument is not provided, the string will be fetched | |
910 | and encoded until a null of appropriate width is found. | |
911 | The length must be a Scheme integer and not a @code{<gdb:value>} integer. | |
912 | @end deffn | |
913 | ||
914 | @deffn {Scheme Procedure} value-lazy? value | |
915 | Return @code{#t} if @var{value} has not yet been fetched | |
916 | from the inferior. | |
917 | Otherwise return @code{#f}. | |
918 | @value{GDBN} does not fetch values until necessary, for efficiency. | |
919 | For example: | |
920 | ||
921 | @smallexample | |
922 | (define myval (parse-and-eval "somevar")) | |
923 | @end smallexample | |
924 | ||
925 | The value of @code{somevar} is not fetched at this time. It will be | |
926 | fetched when the value is needed, or when the @code{fetch-lazy} | |
927 | procedure is invoked. | |
928 | @end deffn | |
929 | ||
930 | @deffn {Scheme Procedure} make-lazy-value type address | |
931 | Return a @code{<gdb:value>} that will be lazily fetched from the target. | |
932 | @var{type} is an object of type @code{<gdb:type>} and @var{address} is | |
933 | a Scheme integer of the address of the object in target memory. | |
934 | @end deffn | |
935 | ||
936 | @deffn {Scheme Procedure} value-fetch-lazy! value | |
937 | If @var{value} is a lazy value (@code{(value-lazy? value)} is @code{#t}), | |
938 | then the value is fetched from the inferior. | |
939 | Any errors that occur in the process will produce a Guile exception. | |
940 | ||
941 | If @var{value} is not a lazy value, this method has no effect. | |
942 | ||
943 | The result of this function is unspecified. | |
944 | @end deffn | |
945 | ||
946 | @deffn {Scheme Procedure} value-print value | |
947 | Return the string representation (print form) of @code{<gdb:value>} | |
948 | @var{value}. | |
949 | @end deffn | |
950 | ||
951 | @node Arithmetic In Guile | |
952 | @subsubsection Arithmetic In Guile | |
953 | ||
954 | The @code{(gdb)} module provides several functions for performing | |
955 | arithmetic on @code{<gdb:value>} objects. | |
956 | The arithmetic is performed as if it were done by the target, | |
957 | and therefore has target semantics which are not necessarily | |
958 | those of Scheme. For example operations work with a fixed precision, | |
959 | not the arbitrary precision of Scheme. | |
960 | ||
961 | Wherever a function takes an integer or pointer as an operand, | |
962 | @value{GDBN} will convert appropriate Scheme values to perform | |
963 | the operation. | |
964 | ||
965 | @deffn {Scheme Procedure} value-add a b | |
966 | @end deffn | |
967 | ||
968 | @deffn {Scheme Procedure} value-sub a b | |
969 | @end deffn | |
970 | ||
971 | @deffn {Scheme Procedure} value-mul a b | |
972 | @end deffn | |
973 | ||
974 | @deffn {Scheme Procedure} value-div a b | |
975 | @end deffn | |
976 | ||
977 | @deffn {Scheme Procedure} value-rem a b | |
978 | @end deffn | |
979 | ||
980 | @deffn {Scheme Procedure} value-mod a b | |
981 | @end deffn | |
982 | ||
983 | @deffn {Scheme Procedure} value-pow a b | |
984 | @end deffn | |
985 | ||
986 | @deffn {Scheme Procedure} value-not a | |
987 | @end deffn | |
988 | ||
989 | @deffn {Scheme Procedure} value-neg a | |
990 | @end deffn | |
991 | ||
992 | @deffn {Scheme Procedure} value-pos a | |
993 | @end deffn | |
994 | ||
995 | @deffn {Scheme Procedure} value-abs a | |
996 | @end deffn | |
997 | ||
998 | @deffn {Scheme Procedure} value-lsh a b | |
999 | @end deffn | |
1000 | ||
1001 | @deffn {Scheme Procedure} value-rsh a b | |
1002 | @end deffn | |
1003 | ||
1004 | @deffn {Scheme Procedure} value-min a b | |
1005 | @end deffn | |
1006 | ||
1007 | @deffn {Scheme Procedure} value-max a b | |
1008 | @end deffn | |
1009 | ||
1010 | @deffn {Scheme Procedure} value-lognot a | |
1011 | @end deffn | |
1012 | ||
1013 | @deffn {Scheme Procedure} value-logand a b | |
1014 | @end deffn | |
1015 | ||
1016 | @deffn {Scheme Procedure} value-logior a b | |
1017 | @end deffn | |
1018 | ||
1019 | @deffn {Scheme Procedure} value-logxor a b | |
1020 | @end deffn | |
1021 | ||
1022 | @deffn {Scheme Procedure} value=? a b | |
1023 | @end deffn | |
1024 | ||
1025 | @deffn {Scheme Procedure} value<? a b | |
1026 | @end deffn | |
1027 | ||
1028 | @deffn {Scheme Procedure} value<=? a b | |
1029 | @end deffn | |
1030 | ||
1031 | @deffn {Scheme Procedure} value>? a b | |
1032 | @end deffn | |
1033 | ||
1034 | @deffn {Scheme Procedure} value>=? a b | |
1035 | @end deffn | |
1036 | ||
1037 | Scheme does not provide a @code{not-equal} function, | |
1038 | and thus Guile support in @value{GDBN} does not either. | |
1039 | ||
1040 | @node Types In Guile | |
1041 | @subsubsection Types In Guile | |
1042 | @cindex types in guile | |
1043 | @cindex guile, working with types | |
1044 | ||
1045 | @tindex <gdb:type> | |
1046 | @value{GDBN} represents types from the inferior in objects of type | |
1047 | @code{<gdb:type>}. | |
1048 | ||
1049 | The following type-related procedures are provided by the | |
1050 | @code{(gdb)} module. | |
1051 | ||
1052 | @deffn {Scheme Procedure} type? object | |
1053 | Return @code{#t} if @var{object} is an object of type @code{<gdb:type>}. | |
1054 | Otherwise return @code{#f}. | |
1055 | @end deffn | |
1056 | ||
1057 | @deffn {Scheme Procedure} lookup-type name @r{[}#:block block@r{]} | |
1058 | This function looks up a type by name. @var{name} is the name of the | |
1059 | type to look up. It must be a string. | |
1060 | ||
1061 | If @var{block} is given, it is an object of type @code{<gdb:block>}, | |
1062 | and @var{name} is looked up in that scope. | |
1063 | Otherwise, it is searched for globally. | |
1064 | ||
1065 | Ordinarily, this function will return an instance of @code{<gdb:type>}. | |
1066 | If the named type cannot be found, it will throw an exception. | |
1067 | @end deffn | |
1068 | ||
1069 | @deffn {Scheme Procedure} type-code type | |
1070 | Return the type code of @var{type}. The type code will be one of the | |
1071 | @code{TYPE_CODE_} constants defined below. | |
1072 | @end deffn | |
1073 | ||
1074 | @deffn {Scheme Procedure} type-tag type | |
1075 | Return the tag name of @var{type}. The tag name is the name after | |
1076 | @code{struct}, @code{union}, or @code{enum} in C and C@t{++}; not all | |
1077 | languages have this concept. If this type has no tag name, then | |
1078 | @code{#f} is returned. | |
1079 | @end deffn | |
1080 | ||
1081 | @deffn {Scheme Procedure} type-name type | |
1082 | Return the name of @var{type}. | |
1083 | If this type has no name, then @code{#f} is returned. | |
1084 | @end deffn | |
1085 | ||
1086 | @deffn {Scheme Procedure} type-print-name type | |
1087 | Return the print name of @var{type}. | |
1088 | This returns something even for anonymous types. | |
1089 | For example, for an anonymous C struct @code{"struct @{...@}"} is returned. | |
1090 | @end deffn | |
1091 | ||
1092 | @deffn {Scheme Procedure} type-sizeof type | |
1093 | Return the size of this type, in target @code{char} units. Usually, a | |
1094 | target's @code{char} type will be an 8-bit byte. However, on some | |
1095 | unusual platforms, this type may have a different size. | |
1096 | @end deffn | |
1097 | ||
1098 | @deffn {Scheme Procedure} type-strip-typedefs type | |
1099 | Return a new @code{<gdb:type>} that represents the real type of @var{type}, | |
1100 | after removing all layers of typedefs. | |
1101 | @end deffn | |
1102 | ||
1103 | @deffn {Scheme Procedure} type-array type n1 @r{[}n2@r{]} | |
1104 | Return a new @code{<gdb:type>} object which represents an array of this | |
1105 | type. If one argument is given, it is the inclusive upper bound of | |
1106 | the array; in this case the lower bound is zero. If two arguments are | |
1107 | given, the first argument is the lower bound of the array, and the | |
1108 | second argument is the upper bound of the array. An array's length | |
1109 | must not be negative, but the bounds can be. | |
1110 | @end deffn | |
1111 | ||
1112 | @deffn {Scheme Procedure} type-vector type n1 @r{[}n2@r{]} | |
1113 | Return a new @code{<gdb:type>} object which represents a vector of this | |
1114 | type. If one argument is given, it is the inclusive upper bound of | |
1115 | the vector; in this case the lower bound is zero. If two arguments are | |
1116 | given, the first argument is the lower bound of the vector, and the | |
1117 | second argument is the upper bound of the vector. A vector's length | |
1118 | must not be negative, but the bounds can be. | |
1119 | ||
1120 | The difference between an @code{array} and a @code{vector} is that | |
1121 | arrays behave like in C: when used in expressions they decay to a pointer | |
1122 | to the first element whereas vectors are treated as first class values. | |
1123 | @end deffn | |
1124 | ||
1125 | @deffn {Scheme Procedure} type-pointer type | |
1126 | Return a new @code{<gdb:type>} object which represents a pointer to | |
1127 | @var{type}. | |
1128 | @end deffn | |
1129 | ||
1130 | @deffn {Scheme Procedure} type-range type | |
1131 | Return a list of two elements: the low bound and high bound of @var{type}. | |
1132 | If @var{type} does not have a range, an exception is thrown. | |
1133 | @end deffn | |
1134 | ||
1135 | @deffn {Scheme Procedure} type-reference type | |
1136 | Return a new @code{<gdb:type>} object which represents a reference to | |
1137 | @var{type}. | |
1138 | @end deffn | |
1139 | ||
1140 | @deffn {Scheme Procedure} type-target type | |
1141 | Return a new @code{<gdb:type>} object which represents the target type | |
1142 | of @var{type}. | |
1143 | ||
1144 | For a pointer type, the target type is the type of the pointed-to | |
1145 | object. For an array type (meaning C-like arrays), the target type is | |
1146 | the type of the elements of the array. For a function or method type, | |
1147 | the target type is the type of the return value. For a complex type, | |
1148 | the target type is the type of the elements. For a typedef, the | |
1149 | target type is the aliased type. | |
1150 | ||
1151 | If the type does not have a target, this method will throw an | |
1152 | exception. | |
1153 | @end deffn | |
1154 | ||
1155 | @deffn {Scheme Procedure} type-const type | |
1156 | Return a new @code{<gdb:type>} object which represents a | |
1157 | @code{const}-qualified variant of @var{type}. | |
1158 | @end deffn | |
1159 | ||
1160 | @deffn {Scheme Procedure} type-volatile type | |
1161 | Return a new @code{<gdb:type>} object which represents a | |
1162 | @code{volatile}-qualified variant of @var{type}. | |
1163 | @end deffn | |
1164 | ||
1165 | @deffn {Scheme Procedure} type-unqualified type | |
1166 | Return a new @code{<gdb:type>} object which represents an unqualified | |
1167 | variant of @var{type}. That is, the result is neither @code{const} nor | |
1168 | @code{volatile}. | |
1169 | @end deffn | |
1170 | ||
1171 | @deffn {Scheme Procedure} type-num-fields | |
1172 | Return the number of fields of @code{<gdb:type>} @var{type}. | |
1173 | @end deffn | |
1174 | ||
1175 | @deffn {Scheme Procedure} type-fields type | |
1176 | Return the fields of @var{type} as a list. | |
1177 | For structure and union types, @code{fields} has the usual meaning. | |
1178 | Range types have two fields, the minimum and maximum values. Enum types | |
1179 | have one field per enum constant. Function and method types have one | |
1180 | field per parameter. The base types of C@t{++} classes are also | |
1181 | represented as fields. If the type has no fields, or does not fit | |
1182 | into one of these categories, an empty list will be returned. | |
1183 | @xref{Fields of a type in Guile}. | |
1184 | @end deffn | |
1185 | ||
1186 | @deffn {Scheme Procedure} make-field-iterator type | |
1187 | Return the fields of @var{type} as a <gdb:iterator> object. | |
1188 | @xref{Iterators In Guile}. | |
1189 | @end deffn | |
1190 | ||
1191 | @deffn {Scheme Procedure} type-field type field-name | |
1192 | Return field named @var{field-name} in @var{type}. | |
1193 | The result is an object of type @code{<gdb:field>}. | |
1194 | @xref{Fields of a type in Guile}. | |
1195 | If the type does not have fields, or @var{field-name} is not a field | |
1196 | of @var{type}, an exception is thrown. | |
1197 | ||
1198 | For example, if @code{some-type} is a @code{<gdb:type>} instance holding | |
1199 | a structure type, you can access its @code{foo} field with: | |
1200 | ||
1201 | @smallexample | |
1202 | (define bar (type-field some-type "foo")) | |
1203 | @end smallexample | |
1204 | ||
1205 | @code{bar} will be a @code{<gdb:field>} object. | |
1206 | @end deffn | |
1207 | ||
1208 | @deffn {Scheme Procedure} type-has-field? type name | |
1209 | Return @code{#t} if @code{<gdb:type>} @var{type} has field named @var{name}. | |
1210 | Otherwise return @code{#f}. | |
1211 | @end deffn | |
1212 | ||
1213 | Each type has a code, which indicates what category this type falls | |
1214 | into. The available type categories are represented by constants | |
1215 | defined in the @code{(gdb)} module: | |
1216 | ||
1217 | @vtable @code | |
1218 | @item TYPE_CODE_PTR | |
1219 | The type is a pointer. | |
1220 | ||
1221 | @item TYPE_CODE_ARRAY | |
1222 | The type is an array. | |
1223 | ||
1224 | @item TYPE_CODE_STRUCT | |
1225 | The type is a structure. | |
1226 | ||
1227 | @item TYPE_CODE_UNION | |
1228 | The type is a union. | |
1229 | ||
1230 | @item TYPE_CODE_ENUM | |
1231 | The type is an enum. | |
1232 | ||
1233 | @item TYPE_CODE_FLAGS | |
1234 | A bit flags type, used for things such as status registers. | |
1235 | ||
1236 | @item TYPE_CODE_FUNC | |
1237 | The type is a function. | |
1238 | ||
1239 | @item TYPE_CODE_INT | |
1240 | The type is an integer type. | |
1241 | ||
1242 | @item TYPE_CODE_FLT | |
1243 | A floating point type. | |
1244 | ||
1245 | @item TYPE_CODE_VOID | |
1246 | The special type @code{void}. | |
1247 | ||
1248 | @item TYPE_CODE_SET | |
1249 | A Pascal set type. | |
1250 | ||
1251 | @item TYPE_CODE_RANGE | |
1252 | A range type, that is, an integer type with bounds. | |
1253 | ||
1254 | @item TYPE_CODE_STRING | |
1255 | A string type. Note that this is only used for certain languages with | |
1256 | language-defined string types; C strings are not represented this way. | |
1257 | ||
1258 | @item TYPE_CODE_BITSTRING | |
1259 | A string of bits. It is deprecated. | |
1260 | ||
1261 | @item TYPE_CODE_ERROR | |
1262 | An unknown or erroneous type. | |
1263 | ||
1264 | @item TYPE_CODE_METHOD | |
1265 | A method type, as found in C@t{++} or Java. | |
1266 | ||
1267 | @item TYPE_CODE_METHODPTR | |
1268 | A pointer-to-member-function. | |
1269 | ||
1270 | @item TYPE_CODE_MEMBERPTR | |
1271 | A pointer-to-member. | |
1272 | ||
1273 | @item TYPE_CODE_REF | |
1274 | A reference type. | |
1275 | ||
1276 | @item TYPE_CODE_CHAR | |
1277 | A character type. | |
1278 | ||
1279 | @item TYPE_CODE_BOOL | |
1280 | A boolean type. | |
1281 | ||
1282 | @item TYPE_CODE_COMPLEX | |
1283 | A complex float type. | |
1284 | ||
1285 | @item TYPE_CODE_TYPEDEF | |
1286 | A typedef to some other type. | |
1287 | ||
1288 | @item TYPE_CODE_NAMESPACE | |
1289 | A C@t{++} namespace. | |
1290 | ||
1291 | @item TYPE_CODE_DECFLOAT | |
1292 | A decimal floating point type. | |
1293 | ||
1294 | @item TYPE_CODE_INTERNAL_FUNCTION | |
1295 | A function internal to @value{GDBN}. This is the type used to represent | |
1296 | convenience functions (@pxref{Convenience Funs}). | |
1297 | @end vtable | |
1298 | ||
1299 | Further support for types is provided in the @code{(gdb types)} | |
1300 | Guile module (@pxref{Guile Types Module}). | |
1301 | ||
1302 | @anchor{Fields of a type in Guile} | |
1303 | Each field is represented as an object of type @code{<gdb:field>}. | |
1304 | ||
1305 | The following field-related procedures are provided by the | |
1306 | @code{(gdb)} module: | |
1307 | ||
1308 | @deffn {Scheme Procedure} field? object | |
1309 | Return @code{#t} if @var{object} is an object of type @code{<gdb:field>}. | |
1310 | Otherwise return @code{#f}. | |
1311 | @end deffn | |
1312 | ||
1313 | @deffn {Scheme Procedure} field-name field | |
1314 | Return the name of the field, or @code{#f} for anonymous fields. | |
1315 | @end deffn | |
1316 | ||
1317 | @deffn {Scheme Procedure} field-type field | |
1318 | Return the type of the field. This is usually an instance of | |
1319 | @code{<gdb:type>}, but it can be @code{#f} in some situations. | |
1320 | @end deffn | |
1321 | ||
1322 | @deffn {Scheme Procedure} field-enumval field | |
1323 | Return the enum value represented by @code{<gdb:field>} @var{field}. | |
1324 | @end deffn | |
1325 | ||
1326 | @deffn {Scheme Procedure} field-bitpos field | |
1327 | Return the bit position of @code{<gdb:field>} @var{field}. | |
1328 | This attribute is not available for @code{static} fields (as in | |
1329 | C@t{++} or Java). | |
1330 | @end deffn | |
1331 | ||
1332 | @deffn {Scheme Procedure} field-bitsize field | |
1333 | If the field is packed, or is a bitfield, return the size of | |
1334 | @code{<gdb:field>} @var{field} in bits. Otherwise, zero is returned; | |
1335 | in which case the field's size is given by its type. | |
1336 | @end deffn | |
1337 | ||
1338 | @deffn {Scheme Procedure} field-artificial? field | |
1339 | Return @code{#t} if the field is artificial, usually meaning that | |
1340 | it was provided by the compiler and not the user. | |
1341 | Otherwise return @code{#f}. | |
1342 | @end deffn | |
1343 | ||
1344 | @deffn {Scheme Procedure} field-base-class? field | |
1345 | Return @code{#t} if the field represents a base class of a C@t{++} | |
1346 | structure. | |
1347 | Otherwise return @code{#f}. | |
1348 | @end deffn | |
1349 | ||
1350 | @node Guile Pretty Printing API | |
1351 | @subsubsection Guile Pretty Printing API | |
1352 | @cindex guile pretty printing api | |
1353 | ||
1354 | An example output is provided (@pxref{Pretty Printing}). | |
1355 | ||
1356 | A pretty-printer is represented by an object of type <gdb:pretty-printer>. | |
1357 | Pretty-printer objects are created with @code{make-pretty-printer}. | |
1358 | ||
1359 | The following pretty-printer-related procedures are provided by the | |
1360 | @code{(gdb)} module: | |
1361 | ||
1362 | @deffn {Scheme Procedure} make-pretty-printer name lookup-function | |
1363 | Return a @code{<gdb:pretty-printer>} object named @var{name}. | |
1364 | ||
1365 | @var{lookup-function} is a function of one parameter: the value to | |
1366 | be printed. If the value is handled by this pretty-printer, then | |
1367 | @var{lookup-function} returns an object of type | |
1368 | <gdb:pretty-printer-worker> to perform the actual pretty-printing. | |
1369 | Otherwise @var{lookup-function} returns @code{#f}. | |
1370 | @end deffn | |
1371 | ||
1372 | @deffn {Scheme Procedure} pretty-printer? object | |
1373 | Return @code{#t} if @var{object} is a @code{<gdb:pretty-printer>} object. | |
1374 | Otherwise return @code{#f}. | |
1375 | @end deffn | |
1376 | ||
1377 | @deffn {Scheme Procedure} pretty-printer-enabled? pretty-printer | |
1378 | Return @code{#t} if @var{pretty-printer} is enabled. | |
1379 | Otherwise return @code{#f}. | |
1380 | @end deffn | |
1381 | ||
1382 | @deffn {Scheme Procedure} set-pretty-printer-enabled! pretty-printer flag | |
1383 | Set the enabled flag of @var{pretty-printer} to @var{flag}. | |
1384 | The value returned in unspecified. | |
1385 | @end deffn | |
1386 | ||
1387 | @deffn {Scheme Procedure} make-pretty-printer-worker display-hint to-string children | |
1388 | Return an object of type @code{<gdb:pretty-printer-worker>}. | |
1389 | ||
1390 | This function takes three parameters: | |
1391 | ||
1392 | @table @samp | |
1393 | @item display-hint | |
1394 | @var{display-hint} provides a hint to @value{GDBN} or @value{GDBN} | |
1395 | front end via MI to change the formatting of the value being printed. | |
1396 | The value must be a string or @code{#f} (meaning there is no hint). | |
1397 | Several values for @var{display-hint} | |
1398 | are predefined by @value{GDBN}: | |
1399 | ||
1400 | @table @samp | |
1401 | @item array | |
1402 | Indicate that the object being printed is ``array-like''. The CLI | |
1403 | uses this to respect parameters such as @code{set print elements} and | |
1404 | @code{set print array}. | |
1405 | ||
1406 | @item map | |
1407 | Indicate that the object being printed is ``map-like'', and that the | |
1408 | children of this value can be assumed to alternate between keys and | |
1409 | values. | |
1410 | ||
1411 | @item string | |
1412 | Indicate that the object being printed is ``string-like''. If the | |
1413 | printer's @code{to-string} function returns a Guile string of some | |
1414 | kind, then @value{GDBN} will call its internal language-specific | |
1415 | string-printing function to format the string. For the CLI this means | |
1416 | adding quotation marks, possibly escaping some characters, respecting | |
1417 | @code{set print elements}, and the like. | |
1418 | @end table | |
1419 | ||
1420 | @item to-string | |
1421 | @var{to-string} is either a function of one parameter, the | |
1422 | @code{<gdb:pretty-printer-worker>} object, or @code{#f}. | |
1423 | ||
1424 | When printing from the CLI, if the @code{to-string} method exists, | |
1425 | then @value{GDBN} will prepend its result to the values returned by | |
1426 | @code{children}. Exactly how this formatting is done is dependent on | |
1427 | the display hint, and may change as more hints are added. Also, | |
1428 | depending on the print settings (@pxref{Print Settings}), the CLI may | |
1429 | print just the result of @code{to-string} in a stack trace, omitting | |
1430 | the result of @code{children}. | |
1431 | ||
1432 | If this method returns a string, it is printed verbatim. | |
1433 | ||
1434 | Otherwise, if this method returns an instance of @code{<gdb:value>}, | |
1435 | then @value{GDBN} prints this value. This may result in a call to | |
1436 | another pretty-printer. | |
1437 | ||
1438 | If instead the method returns a Guile value which is convertible to a | |
1439 | @code{<gdb:value>}, then @value{GDBN} performs the conversion and prints | |
1440 | the resulting value. Again, this may result in a call to another | |
1441 | pretty-printer. Guile scalars (integers, floats, and booleans) and | |
1442 | strings are convertible to @code{<gdb:value>}; other types are not. | |
1443 | ||
1444 | Finally, if this method returns @code{#f} then no further operations | |
1445 | are peformed in this method and nothing is printed. | |
1446 | ||
1447 | If the result is not one of these types, an exception is raised. | |
1448 | ||
1449 | @var{to-string} may also be @code{#f} in which case it is left to | |
1450 | @var{children} to print the value. | |
1451 | ||
1452 | @item children | |
1453 | @var{children} is either a function of one parameter, the | |
1454 | @code{<gdb:pretty-printer-worker>} object, or @code{#f}. | |
1455 | ||
1456 | @value{GDBN} will call this function on a pretty-printer to compute the | |
1457 | children of the pretty-printer's value. | |
1458 | ||
1459 | This function must return a <gdb:iterator> object. | |
1460 | Each item returned by the iterator must be a tuple holding | |
1461 | two elements. The first element is the ``name'' of the child; the | |
1462 | second element is the child's value. The value can be any Guile | |
1463 | object which is convertible to a @value{GDBN} value. | |
1464 | ||
1465 | If @var{children} is @code{#f}, @value{GDBN} will act | |
1466 | as though the value has no children. | |
1467 | @end table | |
1468 | @end deffn | |
1469 | ||
1470 | @value{GDBN} provides a function which can be used to look up the | |
1471 | default pretty-printer for a @code{<gdb:value>}: | |
1472 | ||
1473 | @deffn {Scheme Procedure} default-visualizer value | |
1474 | This function takes a @code{<gdb:value>} object as an argument. If a | |
1475 | pretty-printer for this value exists, then it is returned. If no such | |
1476 | printer exists, then this returns @code{#f}. | |
1477 | @end deffn | |
1478 | ||
1479 | @node Selecting Guile Pretty-Printers | |
1480 | @subsubsection Selecting Guile Pretty-Printers | |
1481 | @cindex selecting guile pretty-printers | |
1482 | ||
1483 | The Guile list @code{*pretty-printers*} contains a set of | |
1484 | @code{<gdb:pretty-printer>} registered objects. | |
1485 | Printers in this list are called @code{global} | |
1486 | printers, they're available when debugging any inferior. | |
1487 | In addition to this, each @code{<gdb:objfile>} object contains its | |
1488 | own set of pretty-printers (@pxref{Objfiles In Guile}). | |
1489 | ||
1490 | Pretty-printer lookup is done by passing the value to be printed to the | |
1491 | lookup function of each enabled object in turn. | |
1492 | Lookup stops when a lookup function returns a non-@code{#f} value | |
1493 | or when the list is exhausted. | |
1494 | ||
1495 | @value{GDBN} first checks the result of @code{objfile-pretty-printers} | |
1496 | of each @code{<gdb:objfile>} in the current program space and iteratively | |
1497 | calls each enabled lookup function in the list for that @code{<gdb:objfile>} | |
1498 | until a non-@code{#f} object is returned. | |
1499 | Lookup functions must return either a @code{<gdb:pretty-printer-worker>} | |
1500 | object or @code{#f}. Otherwise an exception is thrown. | |
1501 | If no pretty-printer is found in the objfile lists, @value{GDBN} then | |
1502 | searches the global pretty-printer list, calling each enabled function | |
1503 | until a non-@code{#f} object is returned. | |
1504 | ||
1505 | The order in which the objfiles are searched is not specified. For a | |
1506 | given list, functions are always invoked from the head of the list, | |
1507 | and iterated over sequentially until the end of the list, or a | |
1508 | @code{<gdb:pretty-printer-worker>} object is returned. | |
1509 | ||
1510 | For various reasons a pretty-printer may not work. | |
1511 | For example, the underlying data structure may have changed and | |
1512 | the pretty-printer is out of date. | |
1513 | ||
1514 | The consequences of a broken pretty-printer are severe enough that | |
1515 | @value{GDBN} provides support for enabling and disabling individual | |
1516 | printers. For example, if @code{print frame-arguments} is on, | |
1517 | a backtrace can become highly illegible if any argument is printed | |
1518 | with a broken printer. | |
1519 | ||
1520 | Pretty-printers are enabled and disabled from Scheme by calling | |
1521 | @code{set-pretty-printer-enabled!}. | |
1522 | @xref{Guile Pretty Printing API}. | |
1523 | ||
1524 | @node Writing a Guile Pretty-Printer | |
1525 | @subsubsection Writing a Guile Pretty-Printer | |
1526 | @cindex writing a Guile pretty-printer | |
1527 | ||
1528 | A pretty-printer consists of two basic parts: a lookup function to determine | |
1529 | if the type is supported, and the printer itself. | |
1530 | ||
1531 | Here is an example showing how a @code{std::string} printer might be | |
1532 | written. @xref{Guile Pretty Printing API}, for details. | |
1533 | ||
1534 | @smallexample | |
1535 | (define (make-my-string-printer value) | |
1536 | "Print a my::string string" | |
1537 | (make-pretty-printer-worker | |
1538 | "string" | |
1539 | (lambda (printer) | |
1540 | (value-field value "_data")) | |
1541 | #f)) | |
1542 | @end smallexample | |
1543 | ||
1544 | And here is an example showing how a lookup function for the printer | |
1545 | example above might be written. | |
1546 | ||
1547 | @smallexample | |
1548 | (define (string-begins-with str prefix) | |
1549 | (= (string-prefix-length str prefix) (string-length prefix))) | |
1550 | ||
1551 | (define (str-lookup-function value) | |
1552 | (let ((tag (type-tag (value-type value)))) | |
1553 | (and tag | |
1554 | (string-begins-with tag "my::string<") | |
1555 | (make-std-string-printer value)))) | |
1556 | @end smallexample | |
1557 | ||
1558 | Then to register this printer in the global printer list: | |
1559 | ||
1560 | @smallexample | |
1561 | (append-pretty-printer! | |
1562 | (make-pretty-printer "my-string" str-lookup-function)) | |
1563 | @end smallexample | |
1564 | ||
1565 | The example lookup function extracts the value's type, and attempts to | |
1566 | match it to a type that it can pretty-print. If it is a type the | |
1567 | printer can pretty-print, it will return a <gdb:pretty-printer-worker> object. | |
1568 | If not, it returns @code{#f}. | |
1569 | ||
1570 | We recommend that you put your core pretty-printers into a Guile | |
1571 | package. If your pretty-printers are for use with a library, we | |
1572 | further recommend embedding a version number into the package name. | |
1573 | This practice will enable @value{GDBN} to load multiple versions of | |
1574 | your pretty-printers at the same time, because they will have | |
1575 | different names. | |
1576 | ||
1577 | You should write auto-loaded code (@pxref{Guile Auto-loading}) such that it | |
1578 | can be evaluated multiple times without changing its meaning. An | |
1579 | ideal auto-load file will consist solely of @code{import}s of your | |
1580 | printer modules, followed by a call to a register pretty-printers with | |
1581 | the current objfile. | |
1582 | ||
1583 | Taken as a whole, this approach will scale nicely to multiple | |
1584 | inferiors, each potentially using a different library version. | |
1585 | Embedding a version number in the Guile package name will ensure that | |
1586 | @value{GDBN} is able to load both sets of printers simultaneously. | |
1587 | Then, because the search for pretty-printers is done by objfile, and | |
1588 | because your auto-loaded code took care to register your library's | |
1589 | printers with a specific objfile, @value{GDBN} will find the correct | |
1590 | printers for the specific version of the library used by each | |
1591 | inferior. | |
1592 | ||
1593 | To continue the @code{my::string} example, | |
1594 | this code might appear in @code{(my-project my-library v1)}: | |
1595 | ||
1596 | @smallexample | |
1597 | (use-modules ((gdb))) | |
1598 | (define (register-printers objfile) | |
1599 | (append-objfile-pretty-printer! | |
1600 | (make-pretty-printer "my-string" str-lookup-function))) | |
1601 | @end smallexample | |
1602 | ||
1603 | @noindent | |
1604 | And then the corresponding contents of the auto-load file would be: | |
1605 | ||
1606 | @smallexample | |
1607 | (use-modules ((gdb) (my-project my-library v1))) | |
1608 | (register-printers (current-objfile)) | |
1609 | @end smallexample | |
1610 | ||
1611 | The previous example illustrates a basic pretty-printer. | |
1612 | There are a few things that can be improved on. | |
1613 | The printer only handles one type, whereas a library typically has | |
1614 | several types. One could install a lookup function for each desired type | |
1615 | in the library, but one could also have a single lookup function recognize | |
1616 | several types. The latter is the conventional way this is handled. | |
1617 | If a pretty-printer can handle multiple data types, then its | |
1618 | @dfn{subprinters} are the printers for the individual data types. | |
1619 | ||
1620 | The @code{(gdb printing)} module provides a formal way of solving this | |
1621 | problem (@pxref{Guile Printing Module}). | |
1622 | Here is another example that handles multiple types. | |
1623 | ||
1624 | These are the types we are going to pretty-print: | |
1625 | ||
1626 | @smallexample | |
1627 | struct foo @{ int a, b; @}; | |
1628 | struct bar @{ struct foo x, y; @}; | |
1629 | @end smallexample | |
1630 | ||
1631 | Here are the printers: | |
1632 | ||
1633 | @smallexample | |
1634 | (define (make-foo-printer value) | |
1635 | "Print a foo object" | |
1636 | (make-pretty-printer-worker | |
1637 | "foo" | |
1638 | (lambda (printer) | |
1639 | (format #f "a=<~a> b=<~a>" | |
1640 | (value-field value "a") (value-field value "a"))) | |
1641 | #f)) | |
1642 | ||
1643 | (define (make-bar-printer value) | |
1644 | "Print a bar object" | |
1645 | (make-pretty-printer-worker | |
1646 | "foo" | |
1647 | (lambda (printer) | |
1648 | (format #f "x=<~a> y=<~a>" | |
1649 | (value-field value "x") (value-field value "y"))) | |
1650 | #f)) | |
1651 | @end smallexample | |
1652 | ||
1653 | This example doesn't need a lookup function, that is handled by the | |
1654 | @code{(gdb printing)} module. Instead a function is provided to build up | |
1655 | the object that handles the lookup. | |
1656 | ||
1657 | @smallexample | |
1658 | (use-modules ((gdb printing))) | |
1659 | ||
1660 | (define (build-pretty-printer) | |
1661 | (let ((pp (make-pretty-printer-collection "my-library"))) | |
1662 | (pp-collection-add-tag-printer "foo" make-foo-printer) | |
1663 | (pp-collection-add-tag-printer "bar" make-bar-printer) | |
1664 | pp)) | |
1665 | @end smallexample | |
1666 | ||
1667 | And here is the autoload support: | |
1668 | ||
1669 | @smallexample | |
1670 | (use-modules ((gdb) (my-library))) | |
1671 | (append-objfile-pretty-printer! (current-objfile) (build-pretty-printer)) | |
1672 | @end smallexample | |
1673 | ||
1674 | Finally, when this printer is loaded into @value{GDBN}, here is the | |
1675 | corresponding output of @samp{info pretty-printer}: | |
1676 | ||
1677 | @smallexample | |
1678 | (gdb) info pretty-printer | |
1679 | my_library.so: | |
1680 | my-library | |
1681 | foo | |
1682 | bar | |
1683 | @end smallexample | |
1684 | ||
1685 | @node Objfiles In Guile | |
1686 | @subsubsection Objfiles In Guile | |
1687 | ||
1688 | @cindex objfiles in guile | |
1689 | @tindex <gdb:objfile> | |
1690 | @value{GDBN} loads symbols for an inferior from various | |
1691 | symbol-containing files (@pxref{Files}). These include the primary | |
1692 | executable file, any shared libraries used by the inferior, and any | |
1693 | separate debug info files (@pxref{Separate Debug Files}). | |
1694 | @value{GDBN} calls these symbol-containing files @dfn{objfiles}. | |
1695 | ||
1696 | Each objfile is represented as an object of type @code{<gdb:objfile>}. | |
1697 | ||
1698 | The following objfile-related procedures are provided by the | |
1699 | @code{(gdb)} module: | |
1700 | ||
1701 | @deffn {Scheme Procedure} objfile? object | |
1702 | Return @code{#t} if @var{object} is a @code{<gdb:objfile>} object. | |
1703 | Otherwise return @code{#f}. | |
1704 | @end deffn | |
1705 | ||
1706 | @deffn {Scheme Procedure} objfile-valid? objfile | |
1707 | Return @code{#t} if @var{objfile} is valid, @code{#f} if not. | |
1708 | A @code{<gdb:objfile>} object can become invalid | |
1709 | if the object file it refers to is not loaded in @value{GDBN} any | |
1710 | longer. All other @code{<gdb:objfile>} procedures will throw an exception | |
1711 | if it is invalid at the time the procedure is called. | |
1712 | @end deffn | |
1713 | ||
1714 | @deffn {Scheme Procedure} objfile-filename objfile | |
1715 | Return the file name of @var{objfile} as a string. | |
1716 | @end deffn | |
1717 | ||
1718 | @deffn {Scheme Procedure} objfile-pretty-printers objfile | |
1719 | Return the list of registered @code{<gdb:pretty-printer>} objects for | |
1720 | @var{objfile}. @xref{Guile Pretty Printing API}, for more information. | |
1721 | @end deffn | |
1722 | ||
1723 | @deffn {Scheme Procedure} set-objfile-pretty-printers! objfile printer-list | |
1724 | Set the list of registered @code{<gdb:pretty-printer>} objects for | |
1725 | @var{objfile} to @var{printer-list}. | |
1726 | @var{printer-list} must be a list of @code{<gdb:pretty-printer>} objects. | |
1727 | @xref{Guile Pretty Printing API}, for more information. | |
1728 | @end deffn | |
1729 | ||
1730 | @deffn {Scheme Procedure} current-objfile | |
1731 | When auto-loading a Guile script (@pxref{Guile Auto-loading}), @value{GDBN} | |
1732 | sets the ``current objfile'' to the corresponding objfile. This | |
1733 | function returns the current objfile. If there is no current objfile, | |
1734 | this function returns @code{#f}. | |
1735 | @end deffn | |
1736 | ||
1737 | @deffn {Scheme Procedure} objfiles | |
1738 | Return a list of all the objfiles in the current program space. | |
1739 | @end deffn | |
1740 | ||
1741 | @node Frames In Guile | |
1742 | @subsubsection Accessing inferior stack frames from Guile. | |
1743 | ||
1744 | @cindex frames in guile | |
1745 | When the debugged program stops, @value{GDBN} is able to analyze its call | |
1746 | stack (@pxref{Frames,,Stack frames}). The @code{<gdb:frame>} class | |
1747 | represents a frame in the stack. A @code{<gdb:frame>} object is only valid | |
1748 | while its corresponding frame exists in the inferior's stack. If you try | |
1749 | to use an invalid frame object, @value{GDBN} will throw a | |
1750 | @code{gdb:invalid-object} exception (@pxref{Guile Exception Handling}). | |
1751 | ||
1752 | Two @code{<gdb:frame>} objects can be compared for equality with the | |
1753 | @code{equal?} function, like: | |
1754 | ||
1755 | @smallexample | |
1756 | (@value{GDBP}) guile (equal? (newest-frame) (selected-frame)) | |
1757 | #t | |
1758 | @end smallexample | |
1759 | ||
1760 | The following frame-related procedures are provided by the | |
1761 | @code{(gdb)} module: | |
1762 | ||
1763 | @deffn {Scheme Procedure} frame? object | |
1764 | Return @code{#t} if @var{object} is a @code{<gdb:frame>} object. | |
1765 | Otherwise return @code{#f}. | |
1766 | @end deffn | |
1767 | ||
1768 | @deffn {Scheme Procedure} frame-valid? frame | |
1769 | Returns @code{#t} if @var{frame} is valid, @code{#f} if not. | |
1770 | A frame object can become invalid if the frame it refers to doesn't | |
1771 | exist anymore in the inferior. All @code{<gdb:frame>} procedures will throw | |
1772 | an exception if the frame is invalid at the time the procedure is called. | |
1773 | @end deffn | |
1774 | ||
1775 | @deffn {Scheme Procedure} frame-name frame | |
1776 | Return the function name of @var{frame}, or @code{#f} if it can't be | |
1777 | obtained. | |
1778 | @end deffn | |
1779 | ||
1780 | @deffn {Scheme Procedure} frame-arch frame | |
1781 | Return the @code{<gdb:architecture>} object corresponding to @var{frame}'s | |
1782 | architecture. @xref{Architectures In Guile}. | |
1783 | @end deffn | |
1784 | ||
1785 | @deffn {Scheme Procedure} frame-type frame | |
1786 | Return the type of @var{frame}. The value can be one of: | |
1787 | ||
1788 | @table @code | |
1789 | @item NORMAL_FRAME | |
1790 | An ordinary stack frame. | |
1791 | ||
1792 | @item DUMMY_FRAME | |
1793 | A fake stack frame that was created by @value{GDBN} when performing an | |
1794 | inferior function call. | |
1795 | ||
1796 | @item INLINE_FRAME | |
1797 | A frame representing an inlined function. The function was inlined | |
1798 | into a @code{NORMAL_FRAME} that is older than this one. | |
1799 | ||
1800 | @item TAILCALL_FRAME | |
1801 | A frame representing a tail call. @xref{Tail Call Frames}. | |
1802 | ||
1803 | @item SIGTRAMP_FRAME | |
1804 | A signal trampoline frame. This is the frame created by the OS when | |
1805 | it calls into a signal handler. | |
1806 | ||
1807 | @item ARCH_FRAME | |
1808 | A fake stack frame representing a cross-architecture call. | |
1809 | ||
1810 | @item SENTINEL_FRAME | |
1811 | This is like @code{NORMAL_FRAME}, but it is only used for the | |
1812 | newest frame. | |
1813 | @end table | |
1814 | @end deffn | |
1815 | ||
1816 | @deffn {Scheme Procedure} frame-unwind-stop-reason frame | |
1817 | Return an integer representing the reason why it's not possible to find | |
1818 | more frames toward the outermost frame. Use | |
1819 | @code{unwind-stop-reason-string} to convert the value returned by this | |
1820 | function to a string. The value can be one of: | |
1821 | ||
1822 | @table @code | |
1823 | @item FRAME_UNWIND_NO_REASON | |
1824 | No particular reason (older frames should be available). | |
1825 | ||
1826 | @item FRAME_UNWIND_NULL_ID | |
1827 | The previous frame's analyzer returns an invalid result. | |
1828 | ||
1829 | @item FRAME_UNWIND_OUTERMOST | |
1830 | This frame is the outermost. | |
1831 | ||
1832 | @item FRAME_UNWIND_UNAVAILABLE | |
1833 | Cannot unwind further, because that would require knowing the | |
1834 | values of registers or memory that have not been collected. | |
1835 | ||
1836 | @item FRAME_UNWIND_INNER_ID | |
1837 | This frame ID looks like it ought to belong to a NEXT frame, | |
1838 | but we got it for a PREV frame. Normally, this is a sign of | |
1839 | unwinder failure. It could also indicate stack corruption. | |
1840 | ||
1841 | @item FRAME_UNWIND_SAME_ID | |
1842 | This frame has the same ID as the previous one. That means | |
1843 | that unwinding further would almost certainly give us another | |
1844 | frame with exactly the same ID, so break the chain. Normally, | |
1845 | this is a sign of unwinder failure. It could also indicate | |
1846 | stack corruption. | |
1847 | ||
1848 | @item FRAME_UNWIND_NO_SAVED_PC | |
1849 | The frame unwinder did not find any saved PC, but we needed | |
1850 | one to unwind further. | |
1851 | ||
1852 | @item FRAME_UNWIND_FIRST_ERROR | |
1853 | Any stop reason greater or equal to this value indicates some kind | |
1854 | of error. This special value facilitates writing code that tests | |
1855 | for errors in unwinding in a way that will work correctly even if | |
1856 | the list of the other values is modified in future @value{GDBN} | |
1857 | versions. Using it, you could write: | |
1858 | ||
1859 | @smallexample | |
1860 | (define reason (frame-unwind-stop-readon (selected-frame))) | |
1861 | (define reason-str (unwind-stop-reason-string reason)) | |
1862 | (if (>= reason FRAME_UNWIND_FIRST_ERROR) | |
1863 | (format #t "An error occured: ~s\n" reason-str)) | |
1864 | @end smallexample | |
1865 | @end table | |
1866 | @end deffn | |
1867 | ||
1868 | @deffn {Scheme Procedure} frame-pc frame | |
1869 | Return the frame's resume address. | |
1870 | @end deffn | |
1871 | ||
1872 | @deffn {Scheme Procedure} frame-block frame | |
1873 | Return the frame's code block as a @code{<gdb:block>} object. | |
1874 | @xref{Blocks In Guile}. | |
1875 | @end deffn | |
1876 | ||
1877 | @deffn {Scheme Procedure} frame-function frame | |
1878 | Return the symbol for the function corresponding to this frame | |
1879 | as a @code{<gdb:symbol>} object, or @code{#f} if there isn't one. | |
1880 | @xref{Symbols In Guile}. | |
1881 | @end deffn | |
1882 | ||
1883 | @deffn {Scheme Procedure} frame-older frame | |
1884 | Return the frame that called @var{frame}. | |
1885 | @end deffn | |
1886 | ||
1887 | @deffn {Scheme Procedure} frame-newer frame | |
1888 | Return the frame called by @var{frame}. | |
1889 | @end deffn | |
1890 | ||
1891 | @deffn {Scheme Procedure} frame-sal frame | |
1892 | Return the frame's @code{<gdb:sal>} (symtab and line) object. | |
1893 | @xref{Symbol Tables In Guile}. | |
1894 | @end deffn | |
1895 | ||
1896 | @deffn {Scheme Procedure} frame-read-var variable @r{[}#:block block@r{]} | |
1897 | Return the value of @var{variable} in this frame. If the optional | |
1898 | argument @var{block} is provided, search for the variable from that | |
1899 | block; otherwise start at the frame's current block (which is | |
1900 | determined by the frame's current program counter). @var{variable} | |
1901 | must be a string or a @code{<gdb:symbol>} object. @var{block} must be a | |
1902 | @code{<gdb:block>} object. | |
1903 | @end deffn | |
1904 | ||
1905 | @deffn {Scheme Procedure} frame-select frame | |
1906 | Set @var{frame} to be the selected frame. @xref{Stack, ,Examining the | |
1907 | Stack}. | |
1908 | @end deffn | |
1909 | ||
1910 | @deffn {Scheme Procedure} selected-frame | |
1911 | Return the selected frame object. @xref{Selection,,Selecting a Frame}. | |
1912 | @end deffn | |
1913 | ||
1914 | @deffn {Scheme Procedure} newest-frame | |
1915 | Return the newest frame object for the selected thread. | |
1916 | @end deffn | |
1917 | ||
1918 | @deffn {Scheme Procedure} unwind-stop-reason-string reason | |
1919 | Return a string explaining the reason why @value{GDBN} stopped unwinding | |
1920 | frames, as expressed by the given @var{reason} code (an integer, see the | |
1921 | @code{frame-unwind-stop-reason} procedure above in this section). | |
1922 | @end deffn | |
1923 | ||
1924 | @node Blocks In Guile | |
1925 | @subsubsection Accessing blocks from Guile. | |
1926 | ||
1927 | @cindex blocks in guile | |
1928 | @tindex <gdb:block> | |
1929 | ||
1930 | In @value{GDBN}, symbols are stored in blocks. A block corresponds | |
1931 | roughly to a scope in the source code. Blocks are organized | |
1932 | hierarchically, and are represented individually in Guile as an object | |
1933 | of type @code{<gdb:block>}. Blocks rely on debugging information being | |
1934 | available. | |
1935 | ||
1936 | A frame has a block. Please see @ref{Frames In Guile}, for a more | |
1937 | in-depth discussion of frames. | |
1938 | ||
1939 | The outermost block is known as the @dfn{global block}. The global | |
1940 | block typically holds public global variables and functions. | |
1941 | ||
1942 | The block nested just inside the global block is the @dfn{static | |
1943 | block}. The static block typically holds file-scoped variables and | |
1944 | functions. | |
1945 | ||
1946 | @value{GDBN} provides a method to get a block's superblock, but there | |
1947 | is currently no way to examine the sub-blocks of a block, or to | |
1948 | iterate over all the blocks in a symbol table (@pxref{Symbol Tables In | |
1949 | Guile}). | |
1950 | ||
1951 | Here is a short example that should help explain blocks: | |
1952 | ||
1953 | @smallexample | |
1954 | /* This is in the global block. */ | |
1955 | int global; | |
1956 | ||
1957 | /* This is in the static block. */ | |
1958 | static int file_scope; | |
1959 | ||
1960 | /* 'function' is in the global block, and 'argument' is | |
1961 | in a block nested inside of 'function'. */ | |
1962 | int function (int argument) | |
1963 | @{ | |
1964 | /* 'local' is in a block inside 'function'. It may or may | |
1965 | not be in the same block as 'argument'. */ | |
1966 | int local; | |
1967 | ||
1968 | @{ | |
1969 | /* 'inner' is in a block whose superblock is the one holding | |
1970 | 'local'. */ | |
1971 | int inner; | |
1972 | ||
1973 | /* If this call is expanded by the compiler, you may see | |
1974 | a nested block here whose function is 'inline_function' | |
1975 | and whose superblock is the one holding 'inner'. */ | |
1976 | inline_function (); | |
1977 | @} | |
1978 | @} | |
1979 | @end smallexample | |
1980 | ||
1981 | The following block-related procedures are provided by the | |
1982 | @code{(gdb)} module: | |
1983 | ||
1984 | @deffn {Scheme Procedure} block? object | |
1985 | Return @code{#t} if @var{object} is a @code{<gdb:block>} object. | |
1986 | Otherwise return @code{#f}. | |
1987 | @end deffn | |
1988 | ||
1989 | @deffn {Scheme Procedure} block-valid? block | |
1990 | Returns @code{#t} if @code{<gdb:block>} @var{block} is valid, | |
1991 | @code{#f} if not. A block object can become invalid if the block it | |
1992 | refers to doesn't exist anymore in the inferior. All other | |
1993 | @code{<gdb:block>} methods will throw an exception if it is invalid at | |
1994 | the time the procedure is called. The block's validity is also checked | |
1995 | during iteration over symbols of the block. | |
1996 | @end deffn | |
1997 | ||
1998 | @deffn {Scheme Procedure} block-start block | |
1999 | Return the start address of @code{<gdb:block>} @var{block}. | |
2000 | @end deffn | |
2001 | ||
2002 | @deffn {Scheme Procedure} block-end block | |
2003 | Return the end address of @code{<gdb:block>} @var{block}. | |
2004 | @end deffn | |
2005 | ||
2006 | @deffn {Scheme Procedure} block-function block | |
2007 | Return the name of @code{<gdb:block>} @var{block} represented as a | |
2008 | @code{<gdb:symbol>} object. | |
2009 | If the block is not named, then @code{#f} is returned. | |
2010 | ||
2011 | For ordinary function blocks, the superblock is the static block. | |
2012 | However, you should note that it is possible for a function block to | |
2013 | have a superblock that is not the static block -- for instance this | |
2014 | happens for an inlined function. | |
2015 | @end deffn | |
2016 | ||
2017 | @deffn {Scheme Procedure} block-superblock block | |
2018 | Return the block containing @code{<gdb:block>} @var{block}. | |
2019 | If the parent block does not exist, then @code{#f} is returned. | |
2020 | @end deffn | |
2021 | ||
2022 | @deffn {Scheme Procedure} block-global-block block | |
2023 | Return the global block associated with @code{<gdb:block>} @var{block}. | |
2024 | @end deffn | |
2025 | ||
2026 | @deffn {Scheme Procedure} block-static-block block | |
2027 | Return the static block associated with @code{<gdb:block>} @var{block}. | |
2028 | @end deffn | |
2029 | ||
2030 | @deffn {Scheme Procedure} block-global? block | |
2031 | Return @code{#t} if @code{<gdb:block>} @var{block} is a global block. | |
2032 | Otherwise return @code{#f}. | |
2033 | @end deffn | |
2034 | ||
2035 | @deffn {Scheme Procedure} block-static? block | |
2036 | Return @code{#t} if @code{<gdb:block>} @var{block} is a static block. | |
2037 | Otherwise return @code{#f}. | |
2038 | @end deffn | |
2039 | ||
2040 | @deffn {Scheme Procedure} block-symbols | |
2041 | Return a list of all symbols (as <gdb:symbol> objects) in | |
2042 | @code{<gdb:block>} @var{block}. | |
2043 | @end deffn | |
2044 | ||
2045 | @deffn {Scheme Procedure} make-block-symbols-iterator block | |
2046 | Return an object of type @code{<gdb:iterator>} that will iterate | |
2047 | over all symbols of the block. | |
2048 | Guile programs should not assume that a specific block object will | |
2049 | always contain a given symbol, since changes in @value{GDBN} features and | |
2050 | infrastructure may cause symbols move across blocks in a symbol table. | |
2051 | @xref{Iterators In Guile}. | |
2052 | @end deffn | |
2053 | ||
2054 | @deffn {Scheme Procedure} block-symbols-progress? | |
2055 | Return #t if the object is a <gdb:block-symbols-progress> object. | |
2056 | This object would be obtained from the @code{progress} element of the | |
2057 | @code{<gdb:iterator>} object returned by @code{make-block-symbols-iterator}. | |
2058 | @end deffn | |
2059 | ||
2060 | @deffn {Scheme Procedure} lookup-block pc | |
2061 | Return the innermost @code{<gdb:block>} containing the given @var{pc} | |
2062 | value. If the block cannot be found for the @var{pc} value specified, | |
2063 | the function will return @code{#f}. | |
2064 | @end deffn | |
2065 | ||
2066 | @node Symbols In Guile | |
2067 | @subsubsection Guile representation of Symbols. | |
2068 | ||
2069 | @cindex symbols in guile | |
2070 | @tindex <gdb:symbol> | |
2071 | ||
2072 | @value{GDBN} represents every variable, function and type as an | |
2073 | entry in a symbol table. @xref{Symbols, ,Examining the Symbol Table}. | |
2074 | Guile represents these symbols in @value{GDBN} with the | |
2075 | @code{<gdb:symbol>} object. | |
2076 | ||
2077 | The following symbol-related procedures are provided by the | |
2078 | @code{(gdb)} module: | |
2079 | ||
2080 | @deffn {Scheme Procedure} symbol? object | |
2081 | Return @code{#t} if @var{object} is an object of type @code{<gdb:symbol>}. | |
2082 | Otherwise return @code{#f}. | |
2083 | @end deffn | |
2084 | ||
2085 | @deffn {Scheme Procedure} symbol-valid? symbol | |
2086 | Return @code{#t} if the @code{<gdb:symbol>} object is valid, | |
2087 | @code{#f} if not. A @code{<gdb:symbol>} object can become invalid if | |
2088 | the symbol it refers to does not exist in @value{GDBN} any longer. | |
2089 | All other @code{<gdb:symbol>} procedures will throw an exception if it is | |
2090 | invalid at the time the procedure is called. | |
2091 | @end deffn | |
2092 | ||
2093 | @deffn {Scheme Procedure} symbol-type symbol | |
2094 | Return the type of @var{symbol} or @code{#f} if no type is recorded. | |
2095 | The result is an object of type @code{<gdb:type>}. | |
2096 | @xref{Types In Guile}. | |
2097 | @end deffn | |
2098 | ||
2099 | @deffn {Scheme Procedure} symbol-symtab symbol | |
2100 | Return the symbol table in which @var{symbol} appears. | |
2101 | The result is an object of type @code{<gdb:symtab>}. | |
2102 | @xref{Symbol Tables In Guile}. | |
2103 | @end deffn | |
2104 | ||
2105 | @deffn {Scheme Procedure} symbol-line symbol | |
2106 | Return the line number in the source code at which @var{symbol} was defined. | |
2107 | This is an integer. | |
2108 | @end deffn | |
2109 | ||
2110 | @deffn {Scheme Procedure} symbol-name symbol | |
2111 | Return the name of @var{symbol} as a string. | |
2112 | @end deffn | |
2113 | ||
2114 | @deffn {Scheme Procedure} symbol-linkage-name symbol | |
2115 | Return the name of @var{symbol}, as used by the linker (i.e., may be mangled). | |
2116 | @end deffn | |
2117 | ||
2118 | @deffn {Scheme Procedure} symbol-print-name symbol | |
2119 | Return the name of @var{symbol} in a form suitable for output. This is either | |
2120 | @code{name} or @code{linkage_name}, depending on whether the user | |
2121 | asked @value{GDBN} to display demangled or mangled names. | |
2122 | @end deffn | |
2123 | ||
2124 | @deffn {Scheme Procedure} symbol-addr-class symbol | |
2125 | Return the address class of the symbol. This classifies how to find the value | |
2126 | of a symbol. Each address class is a constant defined in the | |
2127 | @code{(gdb)} module and described later in this chapter. | |
2128 | @end deffn | |
2129 | ||
2130 | @deffn {Scheme Procedure} symbol-needs-frame? symbol | |
2131 | Return @code{#t} if evaluating @var{symbol}'s value requires a frame | |
2132 | (@pxref{Frames In Guile}) and @code{#f} otherwise. Typically, | |
2133 | local variables will require a frame, but other symbols will not. | |
2134 | @end deffn | |
2135 | ||
2136 | @deffn {Scheme Procedure} symbol-argument? symbol | |
2137 | Return @code{#t} if @var{symbol} is an argument of a function. | |
2138 | Otherwise return @code{#f}. | |
2139 | @end deffn | |
2140 | ||
2141 | @deffn {Scheme Procedure} symbol-constant? symbol | |
2142 | Return @code{#t} if @var{symbol} is a constant. | |
2143 | Otherwise return @code{#f}. | |
2144 | @end deffn | |
2145 | ||
2146 | @deffn {Scheme Procedure} symbol-function? symbol | |
2147 | Return @code{#t} if @var{symbol} is a function or a method. | |
2148 | Otherwise return @code{#f}. | |
2149 | @end deffn | |
2150 | ||
2151 | @deffn {Scheme Procedure} symbol-variable? symbol | |
2152 | Return @code{#t} if @var{symbol} is a variable. | |
2153 | Otherwise return @code{#f}. | |
2154 | @end deffn | |
2155 | ||
2156 | @deffn {Scheme Procedure} symbol-value symbol @r{[}#:frame frame@r{]} | |
2157 | Compute the value of @var{symbol}, as a @code{<gdb:value>}. For | |
2158 | functions, this computes the address of the function, cast to the | |
2159 | appropriate type. If the symbol requires a frame in order to compute | |
2160 | its value, then @var{frame} must be given. If @var{frame} is not | |
2161 | given, or if @var{frame} is invalid, then an exception is thrown. | |
2162 | @end deffn | |
2163 | ||
2164 | @c TODO: line length | |
2165 | @deffn {Scheme Procedure} lookup-symbol name @r{[}#:block block@r{]} @r{[}#:domain domain@r{]} | |
2166 | This function searches for a symbol by name. The search scope can be | |
2167 | restricted to the parameters defined in the optional domain and block | |
2168 | arguments. | |
2169 | ||
2170 | @var{name} is the name of the symbol. It must be a string. The | |
2171 | optional @var{block} argument restricts the search to symbols visible | |
2172 | in that @var{block}. The @var{block} argument must be a | |
2173 | @code{<gdb:block>} object. If omitted, the block for the current frame | |
2174 | is used. The optional @var{domain} argument restricts | |
2175 | the search to the domain type. The @var{domain} argument must be a | |
2176 | domain constant defined in the @code{(gdb)} module and described later | |
2177 | in this chapter. | |
2178 | ||
2179 | The result is a list of two elements. | |
2180 | The first element is a @code{<gdb:symbol>} object or @code{#f} if the symbol | |
2181 | is not found. | |
2182 | If the symbol is found, the second element is @code{#t} if the symbol | |
2183 | is a field of a method's object (e.g., @code{this} in C@t{++}), | |
2184 | otherwise it is @code{#f}. | |
2185 | If the symbol is not found, the second element is @code{#f}. | |
2186 | @end deffn | |
2187 | ||
2188 | @deffn {Scheme Procedure} lookup-global-symbol name @r{[}#:domain domain@r{]} | |
2189 | This function searches for a global symbol by name. | |
2190 | The search scope can be restricted by the domain argument. | |
2191 | ||
2192 | @var{name} is the name of the symbol. It must be a string. | |
2193 | The optional @var{domain} argument restricts the search to the domain type. | |
2194 | The @var{domain} argument must be a domain constant defined in the @code{(gdb)} | |
2195 | module and described later in this chapter. | |
2196 | ||
2197 | The result is a @code{<gdb:symbol>} object or @code{#f} if the symbol | |
2198 | is not found. | |
2199 | @end deffn | |
2200 | ||
2201 | The available domain categories in @code{<gdb:symbol>} are represented | |
2202 | as constants in the @code{(gdb)} module: | |
2203 | ||
2204 | @vtable @code | |
2205 | @item SYMBOL_UNDEF_DOMAIN | |
2206 | This is used when a domain has not been discovered or none of the | |
2207 | following domains apply. This usually indicates an error either | |
2208 | in the symbol information or in @value{GDBN}'s handling of symbols. | |
2209 | ||
2210 | @item SYMBOL_VAR_DOMAIN | |
2211 | This domain contains variables, function names, typedef names and enum | |
2212 | type values. | |
2213 | ||
2214 | @item SYMBOL_STRUCT_DOMAIN | |
2215 | This domain holds struct, union and enum type names. | |
2216 | ||
2217 | @item SYMBOL_LABEL_DOMAIN | |
2218 | This domain contains names of labels (for gotos). | |
2219 | ||
2220 | @item SYMBOL_VARIABLES_DOMAIN | |
2221 | This domain holds a subset of the @code{SYMBOLS_VAR_DOMAIN}; it | |
2222 | contains everything minus functions and types. | |
2223 | ||
2224 | @item SYMBOL_FUNCTION_DOMAIN | |
2225 | This domain contains all functions. | |
2226 | ||
2227 | @item SYMBOL_TYPES_DOMAIN | |
2228 | This domain contains all types. | |
2229 | @end vtable | |
2230 | ||
2231 | The available address class categories in @code{<gdb:symbol>} are represented | |
2232 | as constants in the @code{gdb} module: | |
2233 | ||
2234 | @vtable @code | |
2235 | @item SYMBOL_LOC_UNDEF | |
2236 | If this is returned by address class, it indicates an error either in | |
2237 | the symbol information or in @value{GDBN}'s handling of symbols. | |
2238 | ||
2239 | @item SYMBOL_LOC_CONST | |
2240 | Value is constant int. | |
2241 | ||
2242 | @item SYMBOL_LOC_STATIC | |
2243 | Value is at a fixed address. | |
2244 | ||
2245 | @item SYMBOL_LOC_REGISTER | |
2246 | Value is in a register. | |
2247 | ||
2248 | @item SYMBOL_LOC_ARG | |
2249 | Value is an argument. This value is at the offset stored within the | |
2250 | symbol inside the frame's argument list. | |
2251 | ||
2252 | @item SYMBOL_LOC_REF_ARG | |
2253 | Value address is stored in the frame's argument list. Just like | |
2254 | @code{LOC_ARG} except that the value's address is stored at the | |
2255 | offset, not the value itself. | |
2256 | ||
2257 | @item SYMBOL_LOC_REGPARM_ADDR | |
2258 | Value is a specified register. Just like @code{LOC_REGISTER} except | |
2259 | the register holds the address of the argument instead of the argument | |
2260 | itself. | |
2261 | ||
2262 | @item SYMBOL_LOC_LOCAL | |
2263 | Value is a local variable. | |
2264 | ||
2265 | @item SYMBOL_LOC_TYPEDEF | |
2266 | Value not used. Symbols in the domain @code{SYMBOL_STRUCT_DOMAIN} all | |
2267 | have this class. | |
2268 | ||
2269 | @item SYMBOL_LOC_BLOCK | |
2270 | Value is a block. | |
2271 | ||
2272 | @item SYMBOL_LOC_CONST_BYTES | |
2273 | Value is a byte-sequence. | |
2274 | ||
2275 | @item SYMBOL_LOC_UNRESOLVED | |
2276 | Value is at a fixed address, but the address of the variable has to be | |
2277 | determined from the minimal symbol table whenever the variable is | |
2278 | referenced. | |
2279 | ||
2280 | @item SYMBOL_LOC_OPTIMIZED_OUT | |
2281 | The value does not actually exist in the program. | |
2282 | ||
2283 | @item SYMBOL_LOC_COMPUTED | |
2284 | The value's address is a computed location. | |
2285 | @end vtable | |
2286 | ||
2287 | @node Symbol Tables In Guile | |
2288 | @subsubsection Symbol table representation in Guile. | |
2289 | ||
2290 | @cindex symbol tables in guile | |
2291 | @tindex <gdb:symtab> | |
2292 | @tindex <gdb:sal> | |
2293 | ||
2294 | Access to symbol table data maintained by @value{GDBN} on the inferior | |
2295 | is exposed to Guile via two objects: @code{<gdb:sal>} (symtab-and-line) and | |
2296 | @code{<gdb:symtab>}. Symbol table and line data for a frame is returned | |
2297 | from the @code{frame-find-sal} @code{<gdb:frame>} procedure. | |
2298 | @xref{Frames In Guile}. | |
2299 | ||
2300 | For more information on @value{GDBN}'s symbol table management, see | |
2301 | @ref{Symbols, ,Examining the Symbol Table}. | |
2302 | ||
2303 | The following symtab-related procedures are provided by the | |
2304 | @code{(gdb)} module: | |
2305 | ||
2306 | @deffn {Scheme Procedure} symtab? object | |
2307 | Return @code{#t} if @var{object} is an object of type @code{<gdb:symtab>}. | |
2308 | Otherwise return @code{#f}. | |
2309 | @end deffn | |
2310 | ||
2311 | @deffn {Scheme Procedure} symtab-valid? symtab | |
2312 | Return @code{#t} if the @code{<gdb:symtab>} object is valid, | |
2313 | @code{#f} if not. A @code{<gdb:symtab>} object becomes invalid when | |
2314 | the symbol table it refers to no longer exists in @value{GDBN}. | |
2315 | All other @code{<gdb:symtab>} procedures will throw an exception | |
2316 | if it is invalid at the time the procedure is called. | |
2317 | @end deffn | |
2318 | ||
2319 | @deffn {Scheme Procedure} symtab-filename symtab | |
2320 | Return the symbol table's source filename. | |
2321 | @end deffn | |
2322 | ||
2323 | @deffn {Scheme Procedure} symtab-fullname symtab | |
2324 | Return the symbol table's source absolute file name. | |
2325 | @end deffn | |
2326 | ||
2327 | @deffn {Scheme Procedure} symtab-objfile symtab | |
2328 | Return the symbol table's backing object file. @xref{Objfiles In Guile}. | |
2329 | @end deffn | |
2330 | ||
2331 | @deffn {Scheme Procedure} symtab-global-block symtab | |
2332 | Return the global block of the underlying symbol table. | |
2333 | @xref{Blocks In Guile}. | |
2334 | @end deffn | |
2335 | ||
2336 | @deffn {Scheme Procedure} symtab-static-block symtab | |
2337 | Return the static block of the underlying symbol table. | |
2338 | @xref{Blocks In Guile}. | |
2339 | @end deffn | |
2340 | ||
2341 | The following symtab-and-line-related procedures are provided by the | |
2342 | @code{(gdb)} module: | |
2343 | ||
2344 | @deffn {Scheme Procedure} sal? object | |
2345 | Return @code{#t} if @var{object} is an object of type @code{<gdb:sal>}. | |
2346 | Otherwise return @code{#f}. | |
2347 | @end deffn | |
2348 | ||
2349 | @deffn {Scheme Procedure} sal-valid? sal | |
2350 | Return @code{#t} if @var{sal} is valid, @code{#f} if not. | |
2351 | A @code{<gdb:sal>} object becomes invalid when the Symbol table object | |
2352 | it refers to no longer exists in @value{GDBN}. All other | |
2353 | @code{<gdb:sal>} procedures will throw an exception if it is | |
2354 | invalid at the time the procedure is called. | |
2355 | @end deffn | |
2356 | ||
2357 | @deffn {Scheme Procedure} sal-symtab sal | |
2358 | Return the symbol table object (@code{<gdb:symtab>}) for @var{sal}. | |
2359 | @end deffn | |
2360 | ||
2361 | @deffn {Scheme Procedure} sal-line sal | |
2362 | Return the line number for @var{sal}. | |
2363 | @end deffn | |
2364 | ||
2365 | @deffn {Scheme Procedure} sal-pc sal | |
2366 | Return the start of the address range occupied by code for @var{sal}. | |
2367 | @end deffn | |
2368 | ||
2369 | @deffn {Scheme Procedure} sal-last sal | |
2370 | Return the end of the address range occupied by code for @var{sal}. | |
2371 | @end deffn | |
2372 | ||
2373 | @deffn {Scheme Procedure} find-pc-line pc | |
2374 | Return the @code{<gdb:sal>} object corresponding to the @var{pc} value. | |
2375 | If an invalid value of @var{pc} is passed as an argument, then the | |
2376 | @code{symtab} and @code{line} attributes of the returned @code{<gdb:sal>} | |
2377 | object will be @code{#f} and 0 respectively. | |
2378 | @end deffn | |
2379 | ||
2380 | @node Breakpoints In Guile | |
2381 | @subsubsection Manipulating breakpoints using Guile | |
2382 | ||
2383 | @cindex breakpoints in guile | |
2384 | @tindex <gdb:breakpoint> | |
2385 | ||
2386 | Breakpoints in Guile are represented by objects of type | |
2387 | @code{<gdb:breakpoint>}. | |
2388 | ||
2389 | The following breakpoint-related procedures are provided by the | |
2390 | @code{(gdb)} module: | |
2391 | ||
2392 | @c TODO: line length | |
2393 | @deffn {Scheme Procedure} create-breakpoint! location @r{[}#:type type@r{]} @r{[}#:wp-class wp-class@r{]} @r{[}#:internal internal@r{]} | |
2394 | Create a new breakpoint. @var{spec} is a string naming the | |
2395 | location of the breakpoint, or an expression that defines a watchpoint. | |
2396 | The contents can be any location recognized by the @code{break} command, | |
2397 | or in the case of a watchpoint, by the @code{watch} command. | |
2398 | ||
2399 | The optional @var{type} denotes the breakpoint to create. | |
2400 | This argument can be either: @code{BP_BREAKPOINT} or @code{BP_WATCHPOINT}. | |
2401 | @var{type} defaults to @code{BP_BREAKPOINT}. | |
2402 | ||
2403 | The optional @var{wp-class} argument defines the class of watchpoint to | |
2404 | create, if @var{type} is @code{BP_WATCHPOINT}. If a watchpoint class is | |
2405 | not provided, it is assumed to be a @code{WP_WRITE} class. | |
2406 | ||
2407 | The optional @var{internal} argument allows the breakpoint to become | |
2408 | invisible to the user. The breakpoint will neither be reported when | |
2409 | created, nor will it be listed in the output from @code{info breakpoints} | |
2410 | (but will be listed with the @code{maint info breakpoints} command). | |
2411 | If an internal flag is not provided, the breakpoint is visible | |
2412 | (non-internal). | |
2413 | ||
2414 | When a watchpoint is created, @value{GDBN} will try to create a | |
2415 | hardware assisted watchpoint. If successful, the type of the watchpoint | |
2416 | is changed from @code{BP_WATCHPOINT} to @code{BP_HARDWARE_WATCHPOINT} | |
2417 | for @code{WP_WRITE}, @code{BP_READ_WATCHPOINT} for @code{WP_READ}, | |
2418 | and @code{BP_ACCESS_WATCHPOINT} for @code{WP_ACCESS}. | |
2419 | If not successful, the type of the watchpoint is left as @code{WP_WATCHPOINT}. | |
2420 | ||
2421 | The available types are represented by constants defined in the @code{gdb} | |
2422 | module: | |
2423 | ||
2424 | @vtable @code | |
2425 | @item BP_BREAKPOINT | |
2426 | Normal code breakpoint. | |
2427 | ||
2428 | @item BP_WATCHPOINT | |
2429 | Watchpoint breakpoint. | |
2430 | ||
2431 | @item BP_HARDWARE_WATCHPOINT | |
2432 | Hardware assisted watchpoint. | |
2433 | This value cannot be specified when creating the breakpoint. | |
2434 | ||
2435 | @item BP_READ_WATCHPOINT | |
2436 | Hardware assisted read watchpoint. | |
2437 | This value cannot be specified when creating the breakpoint. | |
2438 | ||
2439 | @item BP_ACCESS_WATCHPOINT | |
2440 | Hardware assisted access watchpoint. | |
2441 | This value cannot be specified when creating the breakpoint. | |
2442 | @end vtable | |
2443 | ||
2444 | The available watchpoint types represented by constants are defined in the | |
2445 | @code{(gdb)} module: | |
2446 | ||
2447 | @vtable @code | |
2448 | @item WP_READ | |
2449 | Read only watchpoint. | |
2450 | ||
2451 | @item WP_WRITE | |
2452 | Write only watchpoint. | |
2453 | ||
2454 | @item WP_ACCESS | |
2455 | Read/Write watchpoint. | |
2456 | @end vtable | |
2457 | ||
2458 | @end deffn | |
2459 | ||
2460 | @deffn {Scheme Procedure} breakpoint-delete! breakpoint | |
2461 | Permanently delete @var{breakpoint}. This also invalidates the | |
2462 | Guile @var{breakpoint} object. Any further attempt to access the | |
2463 | object will throw an exception. | |
2464 | @end deffn | |
2465 | ||
2466 | @deffn {Scheme Procedure} breakpoints | |
2467 | Return a list of all breakpoints. | |
2468 | Each element of the list is a @code{<gdb:breakpoint>} object. | |
2469 | @end deffn | |
2470 | ||
2471 | @deffn {Scheme Procedure} breakpoint? object | |
2472 | Return @code{#t} if @var{object} is a @code{<gdb:breakpoint>} object, | |
2473 | and @code{#f} otherwise. | |
2474 | @end deffn | |
2475 | ||
2476 | @deffn {Scheme Procedure} breakpoint-valid? breakpoint | |
2477 | Return @code{#t} if @var{breakpoint} is valid, @code{#f} otherwise. | |
2478 | A @code{<gdb:breakpoint>} object can become invalid | |
2479 | if the user deletes the breakpoint. In this case, the object still | |
2480 | exists, but the underlying breakpoint does not. In the cases of | |
2481 | watchpoint scope, the watchpoint remains valid even if execution of the | |
2482 | inferior leaves the scope of that watchpoint. | |
2483 | @end deffn | |
2484 | ||
2485 | @deffn {Scheme Procedure} breakpoint-number breakpoint | |
2486 | Return the breakpoint's number --- the identifier used by | |
2487 | the user to manipulate the breakpoint. | |
2488 | @end deffn | |
2489 | ||
2490 | @deffn {Scheme Procedure} breakpoint-type breakpoint | |
2491 | Return the breakpoint's type --- the identifier used to | |
2492 | determine the actual breakpoint type or use-case. | |
2493 | @end deffn | |
2494 | ||
2495 | @deffn {Scheme Procedure} breakpoint-visible? breakpoint | |
2496 | Return @code{#t} if the breakpoint is visible to the user | |
2497 | when hit, or when the @samp{info breakpoints} command is run. | |
2498 | Otherwise return @code{#f}. | |
2499 | @end deffn | |
2500 | ||
2501 | @deffn {Scheme Procedure} breakpoint-location breakpoint | |
2502 | Return the location of the breakpoint, as specified by | |
2503 | the user. It is a string. If the breakpoint does not have a location | |
2504 | (that is, it is a watchpoint) return @code{#f}. | |
2505 | @end deffn | |
2506 | ||
2507 | @deffn {Scheme Procedure} breakpoint-expression breakpoint | |
2508 | Return the breakpoint expression, as specified by the user. It is a string. | |
2509 | If the breakpoint does not have an expression (the breakpoint is not a | |
2510 | watchpoint) return @code{#f}. | |
2511 | @end deffn | |
2512 | ||
2513 | @deffn {Scheme Procedure} breakpoint-enabled? breakpoint | |
2514 | Return @code{#t} if the breakpoint is enabled, and @code{#f} otherwise. | |
2515 | @end deffn | |
2516 | ||
2517 | @deffn {Scheme Procedure} set-breakpoint-enabled! breakpoint flag | |
2518 | Set the enabled state of @var{breakpoint} to @var{flag}. | |
2519 | If flag is @code{#f} it is disabled, otherwise it is enabled. | |
2520 | @end deffn | |
2521 | ||
2522 | @deffn {Scheme Procedure} breakpoint-silent? breakpoint | |
2523 | Return @code{#t} if the breakpoint is silent, and @code{#f} otherwise. | |
2524 | ||
2525 | Note that a breakpoint can also be silent if it has commands and the | |
2526 | first command is @code{silent}. This is not reported by the | |
2527 | @code{silent} attribute. | |
2528 | @end deffn | |
2529 | ||
2530 | @deffn {Scheme Procedure} set-breakpoint-silent! breakpoint flag | |
2531 | Set the silent state of @var{breakpoint} to @var{flag}. | |
2532 | If flag is @code{#f} the breakpoint is made silent, | |
2533 | otherwise it is made non-silent (or noisy). | |
2534 | @end deffn | |
2535 | ||
2536 | @deffn {Scheme Procedure} breakpoint-ignore-count breakpoint | |
2537 | Return the ignore count for @var{breakpoint}. | |
2538 | @end deffn | |
2539 | ||
2540 | @deffn {Scheme Procedure} set-breakpoint-ignore-count! breakpoint count | |
2541 | Set the ignore count for @var{breakpoint} to @var{count}. | |
2542 | @end deffn | |
2543 | ||
2544 | @deffn {Scheme Procedure} breakpoint-hit-count breakpoint | |
2545 | Return hit count of @var{breakpoint}. | |
2546 | @end deffn | |
2547 | ||
2548 | @deffn {Scheme Procedure} set-breakpoint-hit-count! breakpoint count | |
2549 | Set the hit count of @var{breakpoint} to @var{count}. | |
2550 | At present, @var{count} must be zero. | |
2551 | @end deffn | |
2552 | ||
2553 | @deffn {Scheme Procedure} breakpoint-thread breakpoint | |
2554 | Return the thread-id for thread-specific breakpoint @var{breakpoint}. | |
2555 | Return #f if @var{breakpoint} is not thread-specific. | |
2556 | @end deffn | |
2557 | ||
2558 | @deffn {Scheme Procedure} set-breakpoint-thread! breakpoint thread-id|#f | |
2559 | Set the thread-id for @var{breakpoint} to @var{thread-id}. | |
2560 | If set to @code{#f}, the breakpoint is no longer thread-specific. | |
2561 | @end deffn | |
2562 | ||
2563 | @deffn {Scheme Procedure} breakpoint-task breakpoint | |
2564 | If the breakpoint is Ada task-specific, return the Ada task id. | |
2565 | If the breakpoint is not task-specific (or the underlying | |
2566 | language is not Ada), return @code{#f}. | |
2567 | @end deffn | |
2568 | ||
2569 | @deffn {Scheme Procedure} set-breakpoint-task! breakpoint task | |
2570 | Set the Ada task of @var{breakpoint} to @var{task}. | |
2571 | If set to @code{#f}, the breakpoint is no longer task-specific. | |
2572 | @end deffn | |
2573 | ||
2574 | @deffn {Scheme Procedure} breakpoint-condition breakpoint | |
2575 | Return the condition of @var{breakpoint}, as specified by the user. | |
2576 | It is a string. If there is no condition, return @code{#f}. | |
2577 | @end deffn | |
2578 | ||
2579 | @deffn {Scheme Procedure} set-breakpoint-condition! breakpoint condition | |
2580 | Set the condition of @var{breakpoint} to @var{condition}, | |
2581 | which must be a string. If set to @code{#f} then the breakpoint | |
2582 | becomes unconditional. | |
2583 | @end deffn | |
2584 | ||
2585 | @deffn {Scheme Procedure} breakpoint-stop breakpoint | |
2586 | Return the stop predicate of @var{breakpoint}. | |
2587 | See @code{set-breakpoint-stop!} below in this section. | |
2588 | @end deffn | |
2589 | ||
2590 | @deffn {Scheme Procedure} set-breakpoint-stop! breakpoint procedure|#f | |
2591 | Set the stop predicate of @var{breakpoint}. | |
2592 | @var{procedure} takes one argument: the <gdb:breakpoint> object. | |
2593 | If this predicate is set to a procedure then it is invoked whenever | |
2594 | the inferior reaches this breakpoint. If it returns @code{#t}, | |
2595 | or any non-@code{#f} value, then the inferior is stopped, | |
2596 | otherwise the inferior will continue. | |
2597 | ||
2598 | If there are multiple breakpoints at the same location with a | |
2599 | @code{stop} predicate, each one will be called regardless of the | |
2600 | return status of the previous. This ensures that all @code{stop} | |
2601 | predicates have a chance to execute at that location. In this scenario | |
2602 | if one of the methods returns @code{#t} but the others return | |
2603 | @code{#f}, the inferior will still be stopped. | |
2604 | ||
2605 | You should not alter the execution state of the inferior (i.e.@:, step, | |
2606 | next, etc.), alter the current frame context (i.e.@:, change the current | |
2607 | active frame), or alter, add or delete any breakpoint. As a general | |
2608 | rule, you should not alter any data within @value{GDBN} or the inferior | |
2609 | at this time. | |
2610 | ||
2611 | Example @code{stop} implementation: | |
2612 | ||
2613 | @smallexample | |
2614 | (define (my-stop? bkpt) | |
2615 | (let ((int-val (parse-and-eval "foo"))) | |
2616 | (value=? int-val 3))) | |
2617 | (define bkpt (create-breakpoint! "main.c:42")) | |
2618 | (set-breakpoint-stop! bkpt my-stop?) | |
2619 | @end smallexample | |
2620 | @end deffn | |
2621 | ||
2622 | @deffn {Scheme Procedure} breakpoint-commands breakpoint | |
2623 | Return the commands attached to @var{breakpoint} as a string, | |
2624 | or @code{#f} if there are none. | |
2625 | @end deffn | |
2626 | ||
2627 | @node Lazy Strings In Guile | |
2628 | @subsubsection Guile representation of lazy strings. | |
2629 | ||
2630 | @cindex lazy strings in guile | |
2631 | @tindex <gdb:lazy-string> | |
2632 | ||
2633 | A @dfn{lazy string} is a string whose contents is not retrieved or | |
2634 | encoded until it is needed. | |
2635 | ||
2636 | A @code{<gdb:lazy-string>} is represented in @value{GDBN} as an | |
2637 | @code{address} that points to a region of memory, an @code{encoding} | |
2638 | that will be used to encode that region of memory, and a @code{length} | |
2639 | to delimit the region of memory that represents the string. The | |
2640 | difference between a @code{<gdb:lazy-string>} and a string wrapped within | |
2641 | a @code{<gdb:value>} is that a @code{<gdb:lazy-string>} will be treated | |
2642 | differently by @value{GDBN} when printing. A @code{<gdb:lazy-string>} is | |
2643 | retrieved and encoded during printing, while a @code{<gdb:value>} | |
2644 | wrapping a string is immediately retrieved and encoded on creation. | |
2645 | ||
2646 | The following lazy-string-related procedures are provided by the | |
2647 | @code{(gdb)} module: | |
2648 | ||
2649 | @deffn {Scheme Procedure} lazy-string? object | |
2650 | Return @code{#t} if @var{object} is an object of type @code{<gdb:lazy-string>}. | |
2651 | Otherwise return @code{#f}. | |
2652 | @end deffn | |
2653 | ||
2654 | @deffn {Scheme Procedure} lazy-string-address lazy-sring | |
2655 | Return the address of @var{lazy-string}. | |
2656 | @end deffn | |
2657 | ||
2658 | @deffn {Scheme Procedure} lazy-string-length lazy-string | |
2659 | Return the length of @var{lazy-string} in characters. If the | |
2660 | length is -1, then the string will be fetched and encoded up to the | |
2661 | first null of appropriate width. | |
2662 | @end deffn | |
2663 | ||
2664 | @deffn {Scheme Procedure} lazy-string-encoding lazy-string | |
2665 | Return the encoding that will be applied to @var{lazy-string} | |
2666 | when the string is printed by @value{GDBN}. If the encoding is not | |
2667 | set, or contains an empty string, then @value{GDBN} will select the | |
2668 | most appropriate encoding when the string is printed. | |
2669 | @end deffn | |
2670 | ||
2671 | @deffn {Scheme Procedure} lazy-string-type lazy-string | |
2672 | Return the type that is represented by @var{lazy-string}'s type. | |
2673 | For a lazy string this will always be a pointer type. To | |
2674 | resolve this to the lazy string's character type, use @code{type-target-type}. | |
2675 | @xref{Types In Guile}. | |
2676 | @end deffn | |
2677 | ||
2678 | @deffn {Scheme Procedure} lazy-string->value lazy-string | |
2679 | Convert the @code{<gdb:lazy-string>} to a @code{<gdb:value>}. This value | |
2680 | will point to the string in memory, but will lose all the delayed | |
2681 | retrieval, encoding and handling that @value{GDBN} applies to a | |
2682 | @code{<gdb:lazy-string>}. | |
2683 | @end deffn | |
2684 | ||
2685 | @node Architectures In Guile | |
2686 | @subsubsection Guile representation of architectures | |
2687 | ||
2688 | @cindex guile architectures | |
2689 | @tindex <gdb:arch> | |
2690 | ||
2691 | @value{GDBN} uses architecture specific parameters and artifacts in a | |
2692 | number of its various computations. An architecture is represented | |
2693 | by an instance of the @code{<gdb:arch>} class. | |
2694 | ||
2695 | The following architecture-related procedures are provided by the | |
2696 | @code{(gdb)} module: | |
2697 | ||
2698 | @deffn {Scheme Procedure} arch? object | |
2699 | Return @code{#t} if @var{object} is an object of type @code{<gdb:arch>}. | |
2700 | Otherwise return @code{#f}. | |
2701 | @end deffn | |
2702 | ||
2703 | @deffn {Scheme Procedure} current-arch | |
2704 | Return the current architecture as a @code{<gdb:arch>} object. | |
2705 | @end deffn | |
2706 | ||
2707 | @deffn {Scheme Procedure} arch-name arch | |
2708 | Return the name (string value) of @code{<gdb:arch>} @var{arch}. | |
2709 | @end deffn | |
2710 | ||
2711 | @deffn {Scheme Procedure} arch-charset arch | |
2712 | Return name of target character set of @code{<gdb:arch>} @var{arch}. | |
2713 | @end deffn | |
2714 | ||
2715 | @deffn {Scheme Procedure} arch-wide-charset | |
2716 | Return name of target wide character set of @code{<gdb:arch>} @var{arch}. | |
2717 | @end deffn | |
2718 | ||
2719 | Each architecture provides a set of predefined types, obtained by | |
2720 | the following functions. | |
2721 | ||
2722 | @deffn {Scheme Procedure} arch-void-type arch | |
2723 | Return the @code{<gdb:type>} object for a @code{void} type | |
2724 | of architecture @var{arch}. | |
2725 | @end deffn | |
2726 | ||
2727 | @deffn {Scheme Procedure} arch-char-type arch | |
2728 | Return the @code{<gdb:type>} object for a @code{char} type | |
2729 | of architecture @var{arch}. | |
2730 | @end deffn | |
2731 | ||
2732 | @deffn {Scheme Procedure} arch-short-type arch | |
2733 | Return the @code{<gdb:type>} object for a @code{short} type | |
2734 | of architecture @var{arch}. | |
2735 | @end deffn | |
2736 | ||
2737 | @deffn {Scheme Procedure} arch-int-type arch | |
2738 | Return the @code{<gdb:type>} object for an @code{int} type | |
2739 | of architecture @var{arch}. | |
2740 | @end deffn | |
2741 | ||
2742 | @deffn {Scheme Procedure} arch-long-type arch | |
2743 | Return the @code{<gdb:type>} object for a @code{long} type | |
2744 | of architecture @var{arch}. | |
2745 | @end deffn | |
2746 | ||
2747 | @deffn {Scheme Procedure} arch-schar-type arch | |
2748 | Return the @code{<gdb:type>} object for a @code{signed char} type | |
2749 | of architecture @var{arch}. | |
2750 | @end deffn | |
2751 | ||
2752 | @deffn {Scheme Procedure} arch-uchar-type arch | |
2753 | Return the @code{<gdb:type>} object for an @code{unsigned char} type | |
2754 | of architecture @var{arch}. | |
2755 | @end deffn | |
2756 | ||
2757 | @deffn {Scheme Procedure} arch-ushort-type arch | |
2758 | Return the @code{<gdb:type>} object for an @code{unsigned short} type | |
2759 | of architecture @var{arch}. | |
2760 | @end deffn | |
2761 | ||
2762 | @deffn {Scheme Procedure} arch-uint-type arch | |
2763 | Return the @code{<gdb:type>} object for an @code{unsigned int} type | |
2764 | of architecture @var{arch}. | |
2765 | @end deffn | |
2766 | ||
2767 | @deffn {Scheme Procedure} arch-ulong-type arch | |
2768 | Return the @code{<gdb:type>} object for an @code{unsigned long} type | |
2769 | of architecture @var{arch}. | |
2770 | @end deffn | |
2771 | ||
2772 | @deffn {Scheme Procedure} arch-float-type arch | |
2773 | Return the @code{<gdb:type>} object for a @code{float} type | |
2774 | of architecture @var{arch}. | |
2775 | @end deffn | |
2776 | ||
2777 | @deffn {Scheme Procedure} arch-double-type arch | |
2778 | Return the @code{<gdb:type>} object for a @code{double} type | |
2779 | of architecture @var{arch}. | |
2780 | @end deffn | |
2781 | ||
2782 | @deffn {Scheme Procedure} arch-longdouble-type arch | |
2783 | Return the @code{<gdb:type>} object for a @code{long double} type | |
2784 | of architecture @var{arch}. | |
2785 | @end deffn | |
2786 | ||
2787 | @deffn {Scheme Procedure} arch-bool-type arch | |
2788 | Return the @code{<gdb:type>} object for a @code{bool} type | |
2789 | of architecture @var{arch}. | |
2790 | @end deffn | |
2791 | ||
2792 | @deffn {Scheme Procedure} arch-longlong-type arch | |
2793 | Return the @code{<gdb:type>} object for a @code{long long} type | |
2794 | of architecture @var{arch}. | |
2795 | @end deffn | |
2796 | ||
2797 | @deffn {Scheme Procedure} arch-ulonglong-type arch | |
2798 | Return the @code{<gdb:type>} object for an @code{unsigned long long} type | |
2799 | of architecture @var{arch}. | |
2800 | @end deffn | |
2801 | ||
2802 | @deffn {Scheme Procedure} arch-int8-type arch | |
2803 | Return the @code{<gdb:type>} object for an @code{int8} type | |
2804 | of architecture @var{arch}. | |
2805 | @end deffn | |
2806 | ||
2807 | @deffn {Scheme Procedure} arch-uint8-type arch | |
2808 | Return the @code{<gdb:type>} object for a @code{uint8} type | |
2809 | of architecture @var{arch}. | |
2810 | @end deffn | |
2811 | ||
2812 | @deffn {Scheme Procedure} arch-int16-type arch | |
2813 | Return the @code{<gdb:type>} object for an @code{int16} type | |
2814 | of architecture @var{arch}. | |
2815 | @end deffn | |
2816 | ||
2817 | @deffn {Scheme Procedure} arch-uint16-type arch | |
2818 | Return the @code{<gdb:type>} object for a @code{uint16} type | |
2819 | of architecture @var{arch}. | |
2820 | @end deffn | |
2821 | ||
2822 | @deffn {Scheme Procedure} arch-int32-type arch | |
2823 | Return the @code{<gdb:type>} object for an @code{int32} type | |
2824 | of architecture @var{arch}. | |
2825 | @end deffn | |
2826 | ||
2827 | @deffn {Scheme Procedure} arch-uint32-type arch | |
2828 | Return the @code{<gdb:type>} object for a @code{uint32} type | |
2829 | of architecture @var{arch}. | |
2830 | @end deffn | |
2831 | ||
2832 | @deffn {Scheme Procedure} arch-int64-type arch | |
2833 | Return the @code{<gdb:type>} object for an @code{int64} type | |
2834 | of architecture @var{arch}. | |
2835 | @end deffn | |
2836 | ||
2837 | @deffn {Scheme Procedure} arch-uint64-type arch | |
2838 | Return the @code{<gdb:type>} object for a @code{uint64} type | |
2839 | of architecture @var{arch}. | |
2840 | @end deffn | |
2841 | ||
2842 | Example: | |
2843 | ||
2844 | @smallexample | |
2845 | (gdb) guile (type-name (arch-uchar-type (current-arch))) | |
2846 | "unsigned char" | |
2847 | @end smallexample | |
2848 | ||
2849 | @node Disassembly In Guile | |
2850 | @subsubsection Disassembly In Guile | |
2851 | ||
2852 | The disassembler can be invoked from Scheme code. | |
2853 | Furthermore, the disassembler can take a Guile port as input, | |
2854 | allowing one to disassemble from any source, and not just target memory. | |
2855 | ||
2856 | @c TODO: line length | |
6fb526ee | 2857 | @deffn {Scheme Procedure} arch-disassemble arch start-pc @r{[}#:port port@r{]} @r{[}#:offset offset@r{]} @r{[}#:size size@r{]} @r{[}#:count count@r{]} |
ed3ef339 DE |
2858 | Return a list of disassembled instructions starting from the memory |
2859 | address @var{start-pc}. | |
2860 | ||
2861 | The optional argument @var{port} specifies the input port to read bytes from. | |
2862 | If @var{port} is @code{#f} then bytes are read from target memory. | |
2863 | ||
2864 | The optional argument @var{offset} specifies the address offset of the | |
2865 | first byte in @var{port}. This is useful, for example, when @var{port} | |
2866 | specifies a @samp{bytevector} and you want the bytevector to be disassembled | |
2867 | as if it came from that address. The @var{start-pc} passed to the reader | |
2868 | for @var{port} is offset by the same amount. | |
2869 | ||
2870 | Example: | |
2871 | @smallexample | |
2872 | (gdb) guile (use-modules (rnrs io ports)) | |
2873 | (gdb) guile (define pc (value->integer (parse-and-eval "$pc"))) | |
2874 | (gdb) guile (define mem (open-memory #:start pc)) | |
2875 | (gdb) guile (define bv (get-bytevector-n mem 10)) | |
2876 | (gdb) guile (define bv-port (open-bytevector-input-port bv)) | |
2877 | (gdb) guile (define arch (current-arch)) | |
2878 | (gdb) guile (arch-disassemble arch pc #:port bv-port #:offset pc) | |
2879 | (((address . 4195516) (asm . "mov $0x4005c8,%edi") (length . 5))) | |
2880 | @end smallexample | |
2881 | ||
2882 | The optional arguments @var{size} and | |
2883 | @var{count} determine the number of instructions in the returned list. | |
2884 | If either @var{size} or @var{count} is specified as zero, then | |
2885 | no instructions are disassembled and an empty list is returned. | |
2886 | If both the optional arguments @var{size} and @var{count} are | |
2887 | specified, then a list of at most @var{count} disassembled instructions | |
2888 | whose start address falls in the closed memory address interval from | |
2889 | @var{start-pc} to (@var{start-pc} + @var{size} - 1) are returned. | |
2890 | If @var{size} is not specified, but @var{count} is specified, | |
2891 | then @var{count} number of instructions starting from the address | |
2892 | @var{start-pc} are returned. If @var{count} is not specified but | |
2893 | @var{size} is specified, then all instructions whose start address | |
2894 | falls in the closed memory address interval from @var{start-pc} to | |
2895 | (@var{start-pc} + @var{size} - 1) are returned. | |
2896 | If neither @var{size} nor @var{count} are specified, then a single | |
2897 | instruction at @var{start-pc} is returned. | |
2898 | ||
2899 | Each element of the returned list is an alist (associative list) | |
2900 | with the following keys: | |
2901 | ||
2902 | @table @code | |
2903 | ||
2904 | @item address | |
2905 | The value corresponding to this key is a Guile integer of | |
2906 | the memory address of the instruction. | |
2907 | ||
2908 | @item asm | |
2909 | The value corresponding to this key is a string value which represents | |
2910 | the instruction with assembly language mnemonics. The assembly | |
2911 | language flavor used is the same as that specified by the current CLI | |
2912 | variable @code{disassembly-flavor}. @xref{Machine Code}. | |
2913 | ||
2914 | @item length | |
2915 | The value corresponding to this key is the length of the instruction in bytes. | |
2916 | ||
2917 | @end table | |
2918 | @end deffn | |
2919 | ||
2920 | @node I/O Ports in Guile | |
2921 | @subsubsection I/O Ports in Guile | |
2922 | ||
2923 | @deffn {Scheme Procedure} input-port | |
2924 | Return @value{GDBN}'s input port as a Guile port object. | |
2925 | @end deffn | |
2926 | ||
2927 | @deffn {Scheme Procedure} output-port | |
2928 | Return @value{GDBN}'s output port as a Guile port object. | |
2929 | @end deffn | |
2930 | ||
2931 | @deffn {Scheme Procedure} error-port | |
2932 | Return @value{GDBN}'s error port as a Guile port object. | |
2933 | @end deffn | |
2934 | ||
2935 | @deffn {Scheme Procedure} stdio-port? object | |
2936 | Return @code{#t} if @var{object} is a @value{GDBN} stdio port. | |
2937 | Otherwise return @code{#f}. | |
2938 | @end deffn | |
2939 | ||
2940 | @node Memory Ports in Guile | |
2941 | @subsubsection Memory Ports in Guile | |
2942 | ||
2943 | @value{GDBN} provides a @code{port} interface to target memory. | |
2944 | This allows Guile code to read/write target memory using Guile's port and | |
2945 | bytevector functionality. The main routine is @code{open-memory} which | |
2946 | returns a port object. One can then read/write memory using that object. | |
2947 | ||
2948 | @deffn {Scheme Procedure} open-memory @r{[}#:mode mode{]} @r{[}#:start address{]} @r{[}#:size size{]} | |
2949 | Return a port object that can be used for reading and writing memory. | |
2950 | @var{mode} is the standard mode argument to Guile port open routines, | |
2951 | except that it is restricted to one of @samp{"r"}, @samp{"w"}, or @samp{"r+"}. | |
2952 | For compatibility @samp{"b"} (binary) may also be present, | |
2953 | but we ignore it: memory ports are binary only. | |
2954 | The default is @samp{"r"}, read-only. | |
2955 | ||
2956 | The chunk of memory that can be accessed can be bounded. | |
2957 | If both @var{start} and @var{size} are unspecified, all of memory can be | |
2958 | accessed. If only @var{start} is specified, all of memory from that point | |
2959 | on can be accessed. If only @var{size} if specified, all memory in the | |
2960 | range [0,@var{size}) can be accessed. If both are specified, all memory | |
2961 | in the rane [@var{start},@var{start}+@var{size}) can be accessed. | |
2962 | @end deffn | |
2963 | ||
2964 | @deffn {Scheme Procedure} memory-port? | |
2965 | Return @code{#t} if @var{object} is an object of type @code{<gdb:memory-port>}. | |
2966 | Otherwise return @code{#f}. | |
2967 | @end deffn | |
2968 | ||
2969 | @deffn {Scheme Procedure} memory-port-range memory-port | |
2970 | Return the range of @code{<gdb:memory-port>} @var{memory-port} as a list | |
2971 | of two elements: @code{(start end)}. The range is @var{start} to @var{end} | |
2972 | inclusive. | |
2973 | @end deffn | |
2974 | ||
2975 | @deffn {Scheme Procedure} memory-port-read-buffer-size memory-port | |
2976 | Return the size of the read buffer of @code{<gdb:memory-port>} | |
2977 | @var{memory-port}. | |
2978 | @end deffn | |
2979 | ||
2980 | @deffn {Scheme Procedure} set-memory-port-read-buffer-size! memory-port size | |
2981 | Set the size of the read buffer of @code{<gdb:memory-port>} | |
2982 | @var{memory-port} to @var{size}. The result is unspecified. | |
2983 | @end deffn | |
2984 | ||
2985 | @deffn {Scheme Procedure} memory-port-write-buffer-size memory-port | |
2986 | Return the size of the write buffer of @code{<gdb:memory-port>} | |
2987 | @var{memory-port}. | |
2988 | @end deffn | |
2989 | ||
2990 | @deffn {Scheme Procedure} set-memory-port-write-buffer-size! memory-port size | |
2991 | Set the size of the write buffer of @code{<gdb:memory-port>} | |
2992 | @var{memory-port} to @var{size}. The result is unspecified. | |
2993 | @end deffn | |
2994 | ||
2995 | A memory port is closed like any other port, with @code{close-port}. | |
2996 | ||
2997 | Combined with Guile's @code{bytevectors}, memory ports provide a lot | |
2998 | of utility. For example, to fill a buffer of 10 integers in memory, | |
2999 | one can do something like the following. | |
3000 | ||
3001 | @smallexample | |
3002 | ;; In the program: int buffer[10]; | |
3003 | (use-modules (rnrs bytevectors)) | |
3004 | (use-modules (rnrs io ports)) | |
3005 | (define addr (parse-and-eval "buffer")) | |
3006 | (define n 10) | |
3007 | (define byte-size (* n 4)) | |
3008 | (define mem-port (open-memory #:mode "r+" #:start | |
3009 | (value->integer addr) #:size byte-size)) | |
3010 | (define byte-vec (make-bytevector byte-size)) | |
3011 | (do ((i 0 (+ i 1))) | |
3012 | ((>= i n)) | |
3013 | (bytevector-s32-native-set! byte-vec (* i 4) (* i 42))) | |
3014 | (put-bytevector mem-port byte-vec) | |
3015 | (close-port mem-port) | |
3016 | @end smallexample | |
3017 | ||
3018 | @node Iterators In Guile | |
3019 | @subsubsection Iterators In Guile | |
3020 | ||
3021 | @cindex guile iterators | |
3022 | @tindex <gdb:iterator> | |
3023 | ||
3024 | A simple iterator facility is provided to allow, for example, | |
3025 | iterating over the set of program symbols without having to first | |
3026 | construct a list of all of them. A useful contribution would be | |
3027 | to add support for SRFI 41 and SRFI 45. | |
3028 | ||
3029 | @deffn {Scheme Procedure} make-iterator object progress next! | |
3030 | A @code{<gdb:iterator>} object is constructed with the @code{make-iterator} | |
3031 | procedure. It takes three arguments: the object to be iterated over, | |
3032 | an object to record the progress of the iteration, and a procedure to | |
3033 | return the next element in the iteration, or an implementation chosen value | |
3034 | to denote the end of iteration. | |
3035 | ||
3036 | By convention, end of iteration is marked with @code{(end-of-iteration)}, | |
3037 | and may be tested with the @code{end-of-iteration?} predicate. | |
3038 | The result of @code{(end-of-iteration)} is chosen so that it is not | |
3039 | otherwise used by the @code{(gdb)} module. If you are using | |
3040 | @code{<gdb:iterator>} in your own code it is your responsibility to | |
3041 | maintain this invariant. | |
3042 | ||
3043 | A trivial example for illustration's sake: | |
3044 | ||
3045 | @smallexample | |
3046 | (use-modules (gdb iterator)) | |
3047 | (define my-list (list 1 2 3)) | |
3048 | (define iter | |
3049 | (make-iterator my-list my-list | |
3050 | (lambda (iter) | |
3051 | (let ((l (iterator-progress iter))) | |
3052 | (if (eq? l '()) | |
3053 | (end-of-iteration) | |
3054 | (begin | |
3055 | (set-iterator-progress! iter (cdr l)) | |
3056 | (car l))))))) | |
3057 | @end smallexample | |
3058 | ||
3059 | Here is a slightly more realistic example, which computes a list of all the | |
3060 | functions in @code{my-global-block}. | |
3061 | ||
3062 | @smallexample | |
3063 | (use-modules (gdb iterator)) | |
3064 | (define this-sal (find-pc-line (frame-pc (selected-frame)))) | |
3065 | (define this-symtab (sal-symtab this-sal)) | |
3066 | (define this-global-block (symtab-global-block this-symtab)) | |
3067 | (define syms-iter (make-block-symbols-iterator this-global-block)) | |
3068 | (define functions (iterator-filter symbol-function? syms-iter)) | |
3069 | @end smallexample | |
3070 | @end deffn | |
3071 | ||
3072 | @deffn {Scheme Procedure} iterator? object | |
3073 | Return @code{#t} if @var{object} is a @code{<gdb:iterator>} object. | |
3074 | Otherwise return @code{#f}. | |
3075 | @end deffn | |
3076 | ||
3077 | @deffn {Scheme Procedure} iterator-object iterator | |
3078 | Return the first argument that was passed to @code{make-iterator}. | |
3079 | This is the object being iterated over. | |
3080 | @end deffn | |
3081 | ||
3082 | @deffn {Scheme Procedure} iterator-progress iterator | |
3083 | Return the object tracking iteration progress. | |
3084 | @end deffn | |
3085 | ||
3086 | @deffn {Scheme Procedure} set-iterator-progress! iterator new-value | |
3087 | Set the object tracking iteration progress. | |
3088 | @end deffn | |
3089 | ||
3090 | @deffn {Scheme Procedure} iterator-next! iterator | |
3091 | Invoke the procedure that was the third argument to @code{make-iterator}, | |
3092 | passing it one argument, the @code{<gdb:iterator>} object. | |
3093 | The result is either the next element in the iteration, or an end | |
3094 | marker as implemented by the @code{next!} procedure. | |
3095 | By convention the end marker is the result of @code{(end-of-iteration)}. | |
3096 | @end deffn | |
3097 | ||
3098 | @deffn {Scheme Procedure} end-of-iteration | |
3099 | Return the Scheme object that denotes end of iteration. | |
3100 | @end deffn | |
3101 | ||
3102 | @deffn {Scheme Procedure} end-of-iteration? object | |
3103 | Return @code{#t} if @var{object} is the end of iteration marker. | |
3104 | Otherwise return @code{#f}. | |
3105 | @end deffn | |
3106 | ||
3107 | These functions are provided by the @code{(gdb iterator)} module to | |
3108 | assist in using iterators. | |
3109 | ||
3110 | @deffn {Scheme Procedure} make-list-iterator list | |
3111 | Return a @code{<gdb:iterator>} object that will iterate over @var{list}. | |
3112 | @end deffn | |
3113 | ||
3114 | @deffn {Scheme Procedure} iterator->list iterator | |
3115 | Return the elements pointed to by @var{iterator} as a list. | |
3116 | @end deffn | |
3117 | ||
3118 | @deffn {Scheme Procedure} iterator-map proc iterator | |
3119 | Return the list of objects obtained by applying @var{proc} to the object | |
3120 | pointed to by @var{iterator} and to each subsequent object. | |
3121 | @end deffn | |
3122 | ||
3123 | @deffn {Scheme Procedure} iterator-for-each proc iterator | |
3124 | Apply @var{proc} to each element pointed to by @var{iterator}. | |
3125 | The result is unspecified. | |
3126 | @end deffn | |
3127 | ||
3128 | @deffn {Scheme Procedure} iterator-filter pred iterator | |
3129 | Return the list of elements pointed to by @var{iterator} that satisfy | |
3130 | @var{pred}. | |
3131 | @end deffn | |
3132 | ||
3133 | @deffn {Scheme Procedure} iterator-until pred iterator | |
3134 | Run @var{iterator} until the result of @code{(pred element)} is true | |
3135 | and return that as the result. Otherwise return @code{#f}. | |
3136 | @end deffn | |
3137 | ||
3138 | @node Guile Auto-loading | |
3139 | @subsection Guile Auto-loading | |
3140 | @cindex guile auto-loading | |
3141 | ||
3142 | When a new object file is read (for example, due to the @code{file} | |
3143 | command, or because the inferior has loaded a shared library), | |
3144 | @value{GDBN} will look for Guile support scripts in two ways: | |
3145 | @file{@var{objfile}-gdb.scm} and the @code{.debug_gdb_scripts} section. | |
3146 | @xref{Auto-loading extensions}. | |
3147 | ||
3148 | The auto-loading feature is useful for supplying application-specific | |
3149 | debugging commands and scripts. | |
3150 | ||
3151 | Auto-loading can be enabled or disabled, | |
3152 | and the list of auto-loaded scripts can be printed. | |
3153 | ||
3154 | @table @code | |
3155 | @anchor{set auto-load guile-scripts} | |
3156 | @kindex set auto-load guile-scripts | |
3157 | @item set auto-load guile-scripts [on|off] | |
3158 | Enable or disable the auto-loading of Guile scripts. | |
3159 | ||
3160 | @anchor{show auto-load guile-scripts} | |
3161 | @kindex show auto-load guile-scripts | |
3162 | @item show auto-load guile-scripts | |
3163 | Show whether auto-loading of Guile scripts is enabled or disabled. | |
3164 | ||
3165 | @anchor{info auto-load guile-scripts} | |
3166 | @kindex info auto-load guile-scripts | |
3167 | @cindex print list of auto-loaded Guile scripts | |
3168 | @item info auto-load guile-scripts [@var{regexp}] | |
3169 | Print the list of all Guile scripts that @value{GDBN} auto-loaded. | |
3170 | ||
3171 | Also printed is the list of Guile scripts that were mentioned in | |
3172 | the @code{.debug_gdb_scripts} section and were not found. | |
3173 | This is useful because their names are not printed when @value{GDBN} | |
3174 | tries to load them and fails. There may be many of them, and printing | |
3175 | an error message for each one is problematic. | |
3176 | ||
3177 | If @var{regexp} is supplied only Guile scripts with matching names are printed. | |
3178 | ||
3179 | Example: | |
3180 | ||
3181 | @smallexample | |
3182 | (gdb) info auto-load guile-scripts | |
3183 | Loaded Script | |
3184 | Yes scm-section-script.scm | |
3185 | full name: /tmp/scm-section-script.scm | |
3186 | No my-foo-pretty-printers.scm | |
3187 | @end smallexample | |
3188 | @end table | |
3189 | ||
3190 | When reading an auto-loaded file, @value{GDBN} sets the | |
3191 | @dfn{current objfile}. This is available via the @code{current-objfile} | |
3192 | procedure (@pxref{Objfiles In Guile}). This can be useful for | |
3193 | registering objfile-specific pretty-printers. | |
3194 | ||
3195 | @node Guile Modules | |
3196 | @subsection Guile Modules | |
3197 | @cindex guile modules | |
3198 | ||
3199 | @value{GDBN} comes with several modules to assist writing Guile code. | |
3200 | ||
3201 | @menu | |
3202 | * Guile Printing Module:: Building and registering pretty-printers | |
3203 | * Guile Types Module:: Utilities for working with types | |
3204 | @end menu | |
3205 | ||
3206 | @node Guile Printing Module | |
3207 | @subsubsection Guile Printing Module | |
3208 | ||
3209 | This module provides a collection of utilities for working with | |
3210 | pretty-printers. | |
3211 | ||
3212 | Usage: | |
3213 | ||
3214 | @smallexample | |
3215 | (use-modules (gdb printing)) | |
3216 | @end smallexample | |
3217 | ||
3218 | @deffn {Scheme Procedure} prepend-pretty-printer! object printer | |
3219 | Add @var{printer} to the front of the list of pretty-printers for | |
3220 | @var{object}. @var{object} must either be a @code{<gdb:objfile>} object | |
3221 | or @code{#f} in which case @var{printer} is added to the global list of | |
3222 | printers. | |
3223 | @end deffn | |
3224 | ||
3225 | @deffn {Scheme Procecure} append-pretty-printer! object printer | |
3226 | Add @var{printer} to the end of the list of pretty-printers for | |
3227 | @var{object}. @var{object} must either be a @code{<gdb:objfile>} object | |
3228 | or @code{#f} in which case @var{printer} is added to the global list of | |
3229 | printers. | |
3230 | @end deffn | |
3231 | ||
3232 | @node Guile Types Module | |
3233 | @subsubsection Guile Types Module | |
3234 | ||
3235 | This module provides a collection of utilities for working with | |
3236 | @code{<gdb:type>} objects. | |
3237 | ||
3238 | Usage: | |
3239 | ||
3240 | @smallexample | |
3241 | (use-modules (gdb types)) | |
3242 | @end smallexample | |
3243 | ||
3244 | @deffn {Scheme Procedure} get-basic-type type | |
3245 | Return @var{type} with const and volatile qualifiers stripped, | |
3246 | and with typedefs and C@t{++} references converted to the underlying type. | |
3247 | ||
3248 | C@t{++} example: | |
3249 | ||
3250 | @smallexample | |
3251 | typedef const int const_int; | |
3252 | const_int foo (3); | |
3253 | const_int& foo_ref (foo); | |
3254 | int main () @{ return 0; @} | |
3255 | @end smallexample | |
3256 | ||
3257 | Then in gdb: | |
3258 | ||
3259 | @smallexample | |
3260 | (gdb) start | |
3261 | (gdb) guile (use-modules ((gdb) (gdb types))) | |
3262 | (gdb) guile (define foo-ref (parse-and-eval "foo_ref")) | |
3263 | (gdb) guile (get-basic-type (value-type foo-ref)) | |
3264 | int | |
3265 | @end smallexample | |
3266 | @end deffn | |
3267 | ||
3268 | @deffn {Scheme Procedure} type-has-field-deep? type field | |
3269 | Return @code{#t} if @var{type}, assumed to be a type with fields | |
3270 | (e.g., a structure or union), has field @var{field}. | |
3271 | Otherwise return @code{#f}. | |
3272 | This searches baseclasses, whereas @code{type-has-field?} does not. | |
3273 | @end deffn | |
3274 | ||
3275 | @deffn {Scheme Procedure} make-enum-hashtable enum-type | |
3276 | Return a Guile hash table produced from @var{enum-type}. | |
3277 | Elements in the hash table are referenced with @code{hashq-ref}. | |
3278 | @end deffn |