| 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 |
| 889 | @deffn {Scheme Procedure} value->lazy-string value @r{[}#:encoding encoding@r{]} @r{[}#:length length@r{]} |
| 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 (str-lookup-function pretty-printer value) |
| 1549 | (let ((tag (type-tag (value-type value)))) |
| 1550 | (and tag |
| 1551 | (string-prefix? "std::string<" tag) |
| 1552 | (make-my-string-printer value)))) |
| 1553 | @end smallexample |
| 1554 | |
| 1555 | Then to register this printer in the global printer list: |
| 1556 | |
| 1557 | @smallexample |
| 1558 | (append-pretty-printer! |
| 1559 | (make-pretty-printer "my-string" str-lookup-function)) |
| 1560 | @end smallexample |
| 1561 | |
| 1562 | The example lookup function extracts the value's type, and attempts to |
| 1563 | match it to a type that it can pretty-print. If it is a type the |
| 1564 | printer can pretty-print, it will return a <gdb:pretty-printer-worker> object. |
| 1565 | If not, it returns @code{#f}. |
| 1566 | |
| 1567 | We recommend that you put your core pretty-printers into a Guile |
| 1568 | package. If your pretty-printers are for use with a library, we |
| 1569 | further recommend embedding a version number into the package name. |
| 1570 | This practice will enable @value{GDBN} to load multiple versions of |
| 1571 | your pretty-printers at the same time, because they will have |
| 1572 | different names. |
| 1573 | |
| 1574 | You should write auto-loaded code (@pxref{Guile Auto-loading}) such that it |
| 1575 | can be evaluated multiple times without changing its meaning. An |
| 1576 | ideal auto-load file will consist solely of @code{import}s of your |
| 1577 | printer modules, followed by a call to a register pretty-printers with |
| 1578 | the current objfile. |
| 1579 | |
| 1580 | Taken as a whole, this approach will scale nicely to multiple |
| 1581 | inferiors, each potentially using a different library version. |
| 1582 | Embedding a version number in the Guile package name will ensure that |
| 1583 | @value{GDBN} is able to load both sets of printers simultaneously. |
| 1584 | Then, because the search for pretty-printers is done by objfile, and |
| 1585 | because your auto-loaded code took care to register your library's |
| 1586 | printers with a specific objfile, @value{GDBN} will find the correct |
| 1587 | printers for the specific version of the library used by each |
| 1588 | inferior. |
| 1589 | |
| 1590 | To continue the @code{my::string} example, |
| 1591 | this code might appear in @code{(my-project my-library v1)}: |
| 1592 | |
| 1593 | @smallexample |
| 1594 | (use-modules ((gdb))) |
| 1595 | (define (register-printers objfile) |
| 1596 | (append-objfile-pretty-printer! |
| 1597 | (make-pretty-printer "my-string" str-lookup-function))) |
| 1598 | @end smallexample |
| 1599 | |
| 1600 | @noindent |
| 1601 | And then the corresponding contents of the auto-load file would be: |
| 1602 | |
| 1603 | @smallexample |
| 1604 | (use-modules ((gdb) (my-project my-library v1))) |
| 1605 | (register-printers (current-objfile)) |
| 1606 | @end smallexample |
| 1607 | |
| 1608 | The previous example illustrates a basic pretty-printer. |
| 1609 | There are a few things that can be improved on. |
| 1610 | The printer only handles one type, whereas a library typically has |
| 1611 | several types. One could install a lookup function for each desired type |
| 1612 | in the library, but one could also have a single lookup function recognize |
| 1613 | several types. The latter is the conventional way this is handled. |
| 1614 | If a pretty-printer can handle multiple data types, then its |
| 1615 | @dfn{subprinters} are the printers for the individual data types. |
| 1616 | |
| 1617 | The @code{(gdb printing)} module provides a formal way of solving this |
| 1618 | problem (@pxref{Guile Printing Module}). |
| 1619 | Here is another example that handles multiple types. |
| 1620 | |
| 1621 | These are the types we are going to pretty-print: |
| 1622 | |
| 1623 | @smallexample |
| 1624 | struct foo @{ int a, b; @}; |
| 1625 | struct bar @{ struct foo x, y; @}; |
| 1626 | @end smallexample |
| 1627 | |
| 1628 | Here are the printers: |
| 1629 | |
| 1630 | @smallexample |
| 1631 | (define (make-foo-printer value) |
| 1632 | "Print a foo object" |
| 1633 | (make-pretty-printer-worker |
| 1634 | "foo" |
| 1635 | (lambda (printer) |
| 1636 | (format #f "a=<~a> b=<~a>" |
| 1637 | (value-field value "a") (value-field value "a"))) |
| 1638 | #f)) |
| 1639 | |
| 1640 | (define (make-bar-printer value) |
| 1641 | "Print a bar object" |
| 1642 | (make-pretty-printer-worker |
| 1643 | "foo" |
| 1644 | (lambda (printer) |
| 1645 | (format #f "x=<~a> y=<~a>" |
| 1646 | (value-field value "x") (value-field value "y"))) |
| 1647 | #f)) |
| 1648 | @end smallexample |
| 1649 | |
| 1650 | This example doesn't need a lookup function, that is handled by the |
| 1651 | @code{(gdb printing)} module. Instead a function is provided to build up |
| 1652 | the object that handles the lookup. |
| 1653 | |
| 1654 | @smallexample |
| 1655 | (use-modules ((gdb printing))) |
| 1656 | |
| 1657 | (define (build-pretty-printer) |
| 1658 | (let ((pp (make-pretty-printer-collection "my-library"))) |
| 1659 | (pp-collection-add-tag-printer "foo" make-foo-printer) |
| 1660 | (pp-collection-add-tag-printer "bar" make-bar-printer) |
| 1661 | pp)) |
| 1662 | @end smallexample |
| 1663 | |
| 1664 | And here is the autoload support: |
| 1665 | |
| 1666 | @smallexample |
| 1667 | (use-modules ((gdb) (my-library))) |
| 1668 | (append-objfile-pretty-printer! (current-objfile) (build-pretty-printer)) |
| 1669 | @end smallexample |
| 1670 | |
| 1671 | Finally, when this printer is loaded into @value{GDBN}, here is the |
| 1672 | corresponding output of @samp{info pretty-printer}: |
| 1673 | |
| 1674 | @smallexample |
| 1675 | (gdb) info pretty-printer |
| 1676 | my_library.so: |
| 1677 | my-library |
| 1678 | foo |
| 1679 | bar |
| 1680 | @end smallexample |
| 1681 | |
| 1682 | @node Objfiles In Guile |
| 1683 | @subsubsection Objfiles In Guile |
| 1684 | |
| 1685 | @cindex objfiles in guile |
| 1686 | @tindex <gdb:objfile> |
| 1687 | @value{GDBN} loads symbols for an inferior from various |
| 1688 | symbol-containing files (@pxref{Files}). These include the primary |
| 1689 | executable file, any shared libraries used by the inferior, and any |
| 1690 | separate debug info files (@pxref{Separate Debug Files}). |
| 1691 | @value{GDBN} calls these symbol-containing files @dfn{objfiles}. |
| 1692 | |
| 1693 | Each objfile is represented as an object of type @code{<gdb:objfile>}. |
| 1694 | |
| 1695 | The following objfile-related procedures are provided by the |
| 1696 | @code{(gdb)} module: |
| 1697 | |
| 1698 | @deffn {Scheme Procedure} objfile? object |
| 1699 | Return @code{#t} if @var{object} is a @code{<gdb:objfile>} object. |
| 1700 | Otherwise return @code{#f}. |
| 1701 | @end deffn |
| 1702 | |
| 1703 | @deffn {Scheme Procedure} objfile-valid? objfile |
| 1704 | Return @code{#t} if @var{objfile} is valid, @code{#f} if not. |
| 1705 | A @code{<gdb:objfile>} object can become invalid |
| 1706 | if the object file it refers to is not loaded in @value{GDBN} any |
| 1707 | longer. All other @code{<gdb:objfile>} procedures will throw an exception |
| 1708 | if it is invalid at the time the procedure is called. |
| 1709 | @end deffn |
| 1710 | |
| 1711 | @deffn {Scheme Procedure} objfile-filename objfile |
| 1712 | Return the file name of @var{objfile} as a string. |
| 1713 | @end deffn |
| 1714 | |
| 1715 | @deffn {Scheme Procedure} objfile-pretty-printers objfile |
| 1716 | Return the list of registered @code{<gdb:pretty-printer>} objects for |
| 1717 | @var{objfile}. @xref{Guile Pretty Printing API}, for more information. |
| 1718 | @end deffn |
| 1719 | |
| 1720 | @deffn {Scheme Procedure} set-objfile-pretty-printers! objfile printer-list |
| 1721 | Set the list of registered @code{<gdb:pretty-printer>} objects for |
| 1722 | @var{objfile} to @var{printer-list}. |
| 1723 | @var{printer-list} must be a list of @code{<gdb:pretty-printer>} objects. |
| 1724 | @xref{Guile Pretty Printing API}, for more information. |
| 1725 | @end deffn |
| 1726 | |
| 1727 | @deffn {Scheme Procedure} current-objfile |
| 1728 | When auto-loading a Guile script (@pxref{Guile Auto-loading}), @value{GDBN} |
| 1729 | sets the ``current objfile'' to the corresponding objfile. This |
| 1730 | function returns the current objfile. If there is no current objfile, |
| 1731 | this function returns @code{#f}. |
| 1732 | @end deffn |
| 1733 | |
| 1734 | @deffn {Scheme Procedure} objfiles |
| 1735 | Return a list of all the objfiles in the current program space. |
| 1736 | @end deffn |
| 1737 | |
| 1738 | @node Frames In Guile |
| 1739 | @subsubsection Accessing inferior stack frames from Guile. |
| 1740 | |
| 1741 | @cindex frames in guile |
| 1742 | When the debugged program stops, @value{GDBN} is able to analyze its call |
| 1743 | stack (@pxref{Frames,,Stack frames}). The @code{<gdb:frame>} class |
| 1744 | represents a frame in the stack. A @code{<gdb:frame>} object is only valid |
| 1745 | while its corresponding frame exists in the inferior's stack. If you try |
| 1746 | to use an invalid frame object, @value{GDBN} will throw a |
| 1747 | @code{gdb:invalid-object} exception (@pxref{Guile Exception Handling}). |
| 1748 | |
| 1749 | Two @code{<gdb:frame>} objects can be compared for equality with the |
| 1750 | @code{equal?} function, like: |
| 1751 | |
| 1752 | @smallexample |
| 1753 | (@value{GDBP}) guile (equal? (newest-frame) (selected-frame)) |
| 1754 | #t |
| 1755 | @end smallexample |
| 1756 | |
| 1757 | The following frame-related procedures are provided by the |
| 1758 | @code{(gdb)} module: |
| 1759 | |
| 1760 | @deffn {Scheme Procedure} frame? object |
| 1761 | Return @code{#t} if @var{object} is a @code{<gdb:frame>} object. |
| 1762 | Otherwise return @code{#f}. |
| 1763 | @end deffn |
| 1764 | |
| 1765 | @deffn {Scheme Procedure} frame-valid? frame |
| 1766 | Returns @code{#t} if @var{frame} is valid, @code{#f} if not. |
| 1767 | A frame object can become invalid if the frame it refers to doesn't |
| 1768 | exist anymore in the inferior. All @code{<gdb:frame>} procedures will throw |
| 1769 | an exception if the frame is invalid at the time the procedure is called. |
| 1770 | @end deffn |
| 1771 | |
| 1772 | @deffn {Scheme Procedure} frame-name frame |
| 1773 | Return the function name of @var{frame}, or @code{#f} if it can't be |
| 1774 | obtained. |
| 1775 | @end deffn |
| 1776 | |
| 1777 | @deffn {Scheme Procedure} frame-arch frame |
| 1778 | Return the @code{<gdb:architecture>} object corresponding to @var{frame}'s |
| 1779 | architecture. @xref{Architectures In Guile}. |
| 1780 | @end deffn |
| 1781 | |
| 1782 | @deffn {Scheme Procedure} frame-type frame |
| 1783 | Return the type of @var{frame}. The value can be one of: |
| 1784 | |
| 1785 | @table @code |
| 1786 | @item NORMAL_FRAME |
| 1787 | An ordinary stack frame. |
| 1788 | |
| 1789 | @item DUMMY_FRAME |
| 1790 | A fake stack frame that was created by @value{GDBN} when performing an |
| 1791 | inferior function call. |
| 1792 | |
| 1793 | @item INLINE_FRAME |
| 1794 | A frame representing an inlined function. The function was inlined |
| 1795 | into a @code{NORMAL_FRAME} that is older than this one. |
| 1796 | |
| 1797 | @item TAILCALL_FRAME |
| 1798 | A frame representing a tail call. @xref{Tail Call Frames}. |
| 1799 | |
| 1800 | @item SIGTRAMP_FRAME |
| 1801 | A signal trampoline frame. This is the frame created by the OS when |
| 1802 | it calls into a signal handler. |
| 1803 | |
| 1804 | @item ARCH_FRAME |
| 1805 | A fake stack frame representing a cross-architecture call. |
| 1806 | |
| 1807 | @item SENTINEL_FRAME |
| 1808 | This is like @code{NORMAL_FRAME}, but it is only used for the |
| 1809 | newest frame. |
| 1810 | @end table |
| 1811 | @end deffn |
| 1812 | |
| 1813 | @deffn {Scheme Procedure} frame-unwind-stop-reason frame |
| 1814 | Return an integer representing the reason why it's not possible to find |
| 1815 | more frames toward the outermost frame. Use |
| 1816 | @code{unwind-stop-reason-string} to convert the value returned by this |
| 1817 | function to a string. The value can be one of: |
| 1818 | |
| 1819 | @table @code |
| 1820 | @item FRAME_UNWIND_NO_REASON |
| 1821 | No particular reason (older frames should be available). |
| 1822 | |
| 1823 | @item FRAME_UNWIND_NULL_ID |
| 1824 | The previous frame's analyzer returns an invalid result. |
| 1825 | |
| 1826 | @item FRAME_UNWIND_OUTERMOST |
| 1827 | This frame is the outermost. |
| 1828 | |
| 1829 | @item FRAME_UNWIND_UNAVAILABLE |
| 1830 | Cannot unwind further, because that would require knowing the |
| 1831 | values of registers or memory that have not been collected. |
| 1832 | |
| 1833 | @item FRAME_UNWIND_INNER_ID |
| 1834 | This frame ID looks like it ought to belong to a NEXT frame, |
| 1835 | but we got it for a PREV frame. Normally, this is a sign of |
| 1836 | unwinder failure. It could also indicate stack corruption. |
| 1837 | |
| 1838 | @item FRAME_UNWIND_SAME_ID |
| 1839 | This frame has the same ID as the previous one. That means |
| 1840 | that unwinding further would almost certainly give us another |
| 1841 | frame with exactly the same ID, so break the chain. Normally, |
| 1842 | this is a sign of unwinder failure. It could also indicate |
| 1843 | stack corruption. |
| 1844 | |
| 1845 | @item FRAME_UNWIND_NO_SAVED_PC |
| 1846 | The frame unwinder did not find any saved PC, but we needed |
| 1847 | one to unwind further. |
| 1848 | |
| 1849 | @item FRAME_UNWIND_FIRST_ERROR |
| 1850 | Any stop reason greater or equal to this value indicates some kind |
| 1851 | of error. This special value facilitates writing code that tests |
| 1852 | for errors in unwinding in a way that will work correctly even if |
| 1853 | the list of the other values is modified in future @value{GDBN} |
| 1854 | versions. Using it, you could write: |
| 1855 | |
| 1856 | @smallexample |
| 1857 | (define reason (frame-unwind-stop-readon (selected-frame))) |
| 1858 | (define reason-str (unwind-stop-reason-string reason)) |
| 1859 | (if (>= reason FRAME_UNWIND_FIRST_ERROR) |
| 1860 | (format #t "An error occured: ~s\n" reason-str)) |
| 1861 | @end smallexample |
| 1862 | @end table |
| 1863 | @end deffn |
| 1864 | |
| 1865 | @deffn {Scheme Procedure} frame-pc frame |
| 1866 | Return the frame's resume address. |
| 1867 | @end deffn |
| 1868 | |
| 1869 | @deffn {Scheme Procedure} frame-block frame |
| 1870 | Return the frame's code block as a @code{<gdb:block>} object. |
| 1871 | @xref{Blocks In Guile}. |
| 1872 | @end deffn |
| 1873 | |
| 1874 | @deffn {Scheme Procedure} frame-function frame |
| 1875 | Return the symbol for the function corresponding to this frame |
| 1876 | as a @code{<gdb:symbol>} object, or @code{#f} if there isn't one. |
| 1877 | @xref{Symbols In Guile}. |
| 1878 | @end deffn |
| 1879 | |
| 1880 | @deffn {Scheme Procedure} frame-older frame |
| 1881 | Return the frame that called @var{frame}. |
| 1882 | @end deffn |
| 1883 | |
| 1884 | @deffn {Scheme Procedure} frame-newer frame |
| 1885 | Return the frame called by @var{frame}. |
| 1886 | @end deffn |
| 1887 | |
| 1888 | @deffn {Scheme Procedure} frame-sal frame |
| 1889 | Return the frame's @code{<gdb:sal>} (symtab and line) object. |
| 1890 | @xref{Symbol Tables In Guile}. |
| 1891 | @end deffn |
| 1892 | |
| 1893 | @deffn {Scheme Procedure} frame-read-var frame variable @r{[}#:block block@r{]} |
| 1894 | Return the value of @var{variable} in @var{frame}. If the optional |
| 1895 | argument @var{block} is provided, search for the variable from that |
| 1896 | block; otherwise start at the frame's current block (which is |
| 1897 | determined by the frame's current program counter). @var{variable} |
| 1898 | must be a string or a @code{<gdb:symbol>} object. @var{block} must be a |
| 1899 | @code{<gdb:block>} object. |
| 1900 | @end deffn |
| 1901 | |
| 1902 | @deffn {Scheme Procedure} frame-select frame |
| 1903 | Set @var{frame} to be the selected frame. @xref{Stack, ,Examining the |
| 1904 | Stack}. |
| 1905 | @end deffn |
| 1906 | |
| 1907 | @deffn {Scheme Procedure} selected-frame |
| 1908 | Return the selected frame object. @xref{Selection,,Selecting a Frame}. |
| 1909 | @end deffn |
| 1910 | |
| 1911 | @deffn {Scheme Procedure} newest-frame |
| 1912 | Return the newest frame object for the selected thread. |
| 1913 | @end deffn |
| 1914 | |
| 1915 | @deffn {Scheme Procedure} unwind-stop-reason-string reason |
| 1916 | Return a string explaining the reason why @value{GDBN} stopped unwinding |
| 1917 | frames, as expressed by the given @var{reason} code (an integer, see the |
| 1918 | @code{frame-unwind-stop-reason} procedure above in this section). |
| 1919 | @end deffn |
| 1920 | |
| 1921 | @node Blocks In Guile |
| 1922 | @subsubsection Accessing blocks from Guile. |
| 1923 | |
| 1924 | @cindex blocks in guile |
| 1925 | @tindex <gdb:block> |
| 1926 | |
| 1927 | In @value{GDBN}, symbols are stored in blocks. A block corresponds |
| 1928 | roughly to a scope in the source code. Blocks are organized |
| 1929 | hierarchically, and are represented individually in Guile as an object |
| 1930 | of type @code{<gdb:block>}. Blocks rely on debugging information being |
| 1931 | available. |
| 1932 | |
| 1933 | A frame has a block. Please see @ref{Frames In Guile}, for a more |
| 1934 | in-depth discussion of frames. |
| 1935 | |
| 1936 | The outermost block is known as the @dfn{global block}. The global |
| 1937 | block typically holds public global variables and functions. |
| 1938 | |
| 1939 | The block nested just inside the global block is the @dfn{static |
| 1940 | block}. The static block typically holds file-scoped variables and |
| 1941 | functions. |
| 1942 | |
| 1943 | @value{GDBN} provides a method to get a block's superblock, but there |
| 1944 | is currently no way to examine the sub-blocks of a block, or to |
| 1945 | iterate over all the blocks in a symbol table (@pxref{Symbol Tables In |
| 1946 | Guile}). |
| 1947 | |
| 1948 | Here is a short example that should help explain blocks: |
| 1949 | |
| 1950 | @smallexample |
| 1951 | /* This is in the global block. */ |
| 1952 | int global; |
| 1953 | |
| 1954 | /* This is in the static block. */ |
| 1955 | static int file_scope; |
| 1956 | |
| 1957 | /* 'function' is in the global block, and 'argument' is |
| 1958 | in a block nested inside of 'function'. */ |
| 1959 | int function (int argument) |
| 1960 | @{ |
| 1961 | /* 'local' is in a block inside 'function'. It may or may |
| 1962 | not be in the same block as 'argument'. */ |
| 1963 | int local; |
| 1964 | |
| 1965 | @{ |
| 1966 | /* 'inner' is in a block whose superblock is the one holding |
| 1967 | 'local'. */ |
| 1968 | int inner; |
| 1969 | |
| 1970 | /* If this call is expanded by the compiler, you may see |
| 1971 | a nested block here whose function is 'inline_function' |
| 1972 | and whose superblock is the one holding 'inner'. */ |
| 1973 | inline_function (); |
| 1974 | @} |
| 1975 | @} |
| 1976 | @end smallexample |
| 1977 | |
| 1978 | The following block-related procedures are provided by the |
| 1979 | @code{(gdb)} module: |
| 1980 | |
| 1981 | @deffn {Scheme Procedure} block? object |
| 1982 | Return @code{#t} if @var{object} is a @code{<gdb:block>} object. |
| 1983 | Otherwise return @code{#f}. |
| 1984 | @end deffn |
| 1985 | |
| 1986 | @deffn {Scheme Procedure} block-valid? block |
| 1987 | Returns @code{#t} if @code{<gdb:block>} @var{block} is valid, |
| 1988 | @code{#f} if not. A block object can become invalid if the block it |
| 1989 | refers to doesn't exist anymore in the inferior. All other |
| 1990 | @code{<gdb:block>} methods will throw an exception if it is invalid at |
| 1991 | the time the procedure is called. The block's validity is also checked |
| 1992 | during iteration over symbols of the block. |
| 1993 | @end deffn |
| 1994 | |
| 1995 | @deffn {Scheme Procedure} block-start block |
| 1996 | Return the start address of @code{<gdb:block>} @var{block}. |
| 1997 | @end deffn |
| 1998 | |
| 1999 | @deffn {Scheme Procedure} block-end block |
| 2000 | Return the end address of @code{<gdb:block>} @var{block}. |
| 2001 | @end deffn |
| 2002 | |
| 2003 | @deffn {Scheme Procedure} block-function block |
| 2004 | Return the name of @code{<gdb:block>} @var{block} represented as a |
| 2005 | @code{<gdb:symbol>} object. |
| 2006 | If the block is not named, then @code{#f} is returned. |
| 2007 | |
| 2008 | For ordinary function blocks, the superblock is the static block. |
| 2009 | However, you should note that it is possible for a function block to |
| 2010 | have a superblock that is not the static block -- for instance this |
| 2011 | happens for an inlined function. |
| 2012 | @end deffn |
| 2013 | |
| 2014 | @deffn {Scheme Procedure} block-superblock block |
| 2015 | Return the block containing @code{<gdb:block>} @var{block}. |
| 2016 | If the parent block does not exist, then @code{#f} is returned. |
| 2017 | @end deffn |
| 2018 | |
| 2019 | @deffn {Scheme Procedure} block-global-block block |
| 2020 | Return the global block associated with @code{<gdb:block>} @var{block}. |
| 2021 | @end deffn |
| 2022 | |
| 2023 | @deffn {Scheme Procedure} block-static-block block |
| 2024 | Return the static block associated with @code{<gdb:block>} @var{block}. |
| 2025 | @end deffn |
| 2026 | |
| 2027 | @deffn {Scheme Procedure} block-global? block |
| 2028 | Return @code{#t} if @code{<gdb:block>} @var{block} is a global block. |
| 2029 | Otherwise return @code{#f}. |
| 2030 | @end deffn |
| 2031 | |
| 2032 | @deffn {Scheme Procedure} block-static? block |
| 2033 | Return @code{#t} if @code{<gdb:block>} @var{block} is a static block. |
| 2034 | Otherwise return @code{#f}. |
| 2035 | @end deffn |
| 2036 | |
| 2037 | @deffn {Scheme Procedure} block-symbols |
| 2038 | Return a list of all symbols (as <gdb:symbol> objects) in |
| 2039 | @code{<gdb:block>} @var{block}. |
| 2040 | @end deffn |
| 2041 | |
| 2042 | @deffn {Scheme Procedure} make-block-symbols-iterator block |
| 2043 | Return an object of type @code{<gdb:iterator>} that will iterate |
| 2044 | over all symbols of the block. |
| 2045 | Guile programs should not assume that a specific block object will |
| 2046 | always contain a given symbol, since changes in @value{GDBN} features and |
| 2047 | infrastructure may cause symbols move across blocks in a symbol table. |
| 2048 | @xref{Iterators In Guile}. |
| 2049 | @end deffn |
| 2050 | |
| 2051 | @deffn {Scheme Procedure} block-symbols-progress? |
| 2052 | Return #t if the object is a <gdb:block-symbols-progress> object. |
| 2053 | This object would be obtained from the @code{progress} element of the |
| 2054 | @code{<gdb:iterator>} object returned by @code{make-block-symbols-iterator}. |
| 2055 | @end deffn |
| 2056 | |
| 2057 | @deffn {Scheme Procedure} lookup-block pc |
| 2058 | Return the innermost @code{<gdb:block>} containing the given @var{pc} |
| 2059 | value. If the block cannot be found for the @var{pc} value specified, |
| 2060 | the function will return @code{#f}. |
| 2061 | @end deffn |
| 2062 | |
| 2063 | @node Symbols In Guile |
| 2064 | @subsubsection Guile representation of Symbols. |
| 2065 | |
| 2066 | @cindex symbols in guile |
| 2067 | @tindex <gdb:symbol> |
| 2068 | |
| 2069 | @value{GDBN} represents every variable, function and type as an |
| 2070 | entry in a symbol table. @xref{Symbols, ,Examining the Symbol Table}. |
| 2071 | Guile represents these symbols in @value{GDBN} with the |
| 2072 | @code{<gdb:symbol>} object. |
| 2073 | |
| 2074 | The following symbol-related procedures are provided by the |
| 2075 | @code{(gdb)} module: |
| 2076 | |
| 2077 | @deffn {Scheme Procedure} symbol? object |
| 2078 | Return @code{#t} if @var{object} is an object of type @code{<gdb:symbol>}. |
| 2079 | Otherwise return @code{#f}. |
| 2080 | @end deffn |
| 2081 | |
| 2082 | @deffn {Scheme Procedure} symbol-valid? symbol |
| 2083 | Return @code{#t} if the @code{<gdb:symbol>} object is valid, |
| 2084 | @code{#f} if not. A @code{<gdb:symbol>} object can become invalid if |
| 2085 | the symbol it refers to does not exist in @value{GDBN} any longer. |
| 2086 | All other @code{<gdb:symbol>} procedures will throw an exception if it is |
| 2087 | invalid at the time the procedure is called. |
| 2088 | @end deffn |
| 2089 | |
| 2090 | @deffn {Scheme Procedure} symbol-type symbol |
| 2091 | Return the type of @var{symbol} or @code{#f} if no type is recorded. |
| 2092 | The result is an object of type @code{<gdb:type>}. |
| 2093 | @xref{Types In Guile}. |
| 2094 | @end deffn |
| 2095 | |
| 2096 | @deffn {Scheme Procedure} symbol-symtab symbol |
| 2097 | Return the symbol table in which @var{symbol} appears. |
| 2098 | The result is an object of type @code{<gdb:symtab>}. |
| 2099 | @xref{Symbol Tables In Guile}. |
| 2100 | @end deffn |
| 2101 | |
| 2102 | @deffn {Scheme Procedure} symbol-line symbol |
| 2103 | Return the line number in the source code at which @var{symbol} was defined. |
| 2104 | This is an integer. |
| 2105 | @end deffn |
| 2106 | |
| 2107 | @deffn {Scheme Procedure} symbol-name symbol |
| 2108 | Return the name of @var{symbol} as a string. |
| 2109 | @end deffn |
| 2110 | |
| 2111 | @deffn {Scheme Procedure} symbol-linkage-name symbol |
| 2112 | Return the name of @var{symbol}, as used by the linker (i.e., may be mangled). |
| 2113 | @end deffn |
| 2114 | |
| 2115 | @deffn {Scheme Procedure} symbol-print-name symbol |
| 2116 | Return the name of @var{symbol} in a form suitable for output. This is either |
| 2117 | @code{name} or @code{linkage_name}, depending on whether the user |
| 2118 | asked @value{GDBN} to display demangled or mangled names. |
| 2119 | @end deffn |
| 2120 | |
| 2121 | @deffn {Scheme Procedure} symbol-addr-class symbol |
| 2122 | Return the address class of the symbol. This classifies how to find the value |
| 2123 | of a symbol. Each address class is a constant defined in the |
| 2124 | @code{(gdb)} module and described later in this chapter. |
| 2125 | @end deffn |
| 2126 | |
| 2127 | @deffn {Scheme Procedure} symbol-needs-frame? symbol |
| 2128 | Return @code{#t} if evaluating @var{symbol}'s value requires a frame |
| 2129 | (@pxref{Frames In Guile}) and @code{#f} otherwise. Typically, |
| 2130 | local variables will require a frame, but other symbols will not. |
| 2131 | @end deffn |
| 2132 | |
| 2133 | @deffn {Scheme Procedure} symbol-argument? symbol |
| 2134 | Return @code{#t} if @var{symbol} is an argument of a function. |
| 2135 | Otherwise return @code{#f}. |
| 2136 | @end deffn |
| 2137 | |
| 2138 | @deffn {Scheme Procedure} symbol-constant? symbol |
| 2139 | Return @code{#t} if @var{symbol} is a constant. |
| 2140 | Otherwise return @code{#f}. |
| 2141 | @end deffn |
| 2142 | |
| 2143 | @deffn {Scheme Procedure} symbol-function? symbol |
| 2144 | Return @code{#t} if @var{symbol} is a function or a method. |
| 2145 | Otherwise return @code{#f}. |
| 2146 | @end deffn |
| 2147 | |
| 2148 | @deffn {Scheme Procedure} symbol-variable? symbol |
| 2149 | Return @code{#t} if @var{symbol} is a variable. |
| 2150 | Otherwise return @code{#f}. |
| 2151 | @end deffn |
| 2152 | |
| 2153 | @deffn {Scheme Procedure} symbol-value symbol @r{[}#:frame frame@r{]} |
| 2154 | Compute the value of @var{symbol}, as a @code{<gdb:value>}. For |
| 2155 | functions, this computes the address of the function, cast to the |
| 2156 | appropriate type. If the symbol requires a frame in order to compute |
| 2157 | its value, then @var{frame} must be given. If @var{frame} is not |
| 2158 | given, or if @var{frame} is invalid, then an exception is thrown. |
| 2159 | @end deffn |
| 2160 | |
| 2161 | @c TODO: line length |
| 2162 | @deffn {Scheme Procedure} lookup-symbol name @r{[}#:block block@r{]} @r{[}#:domain domain@r{]} |
| 2163 | This function searches for a symbol by name. The search scope can be |
| 2164 | restricted to the parameters defined in the optional domain and block |
| 2165 | arguments. |
| 2166 | |
| 2167 | @var{name} is the name of the symbol. It must be a string. The |
| 2168 | optional @var{block} argument restricts the search to symbols visible |
| 2169 | in that @var{block}. The @var{block} argument must be a |
| 2170 | @code{<gdb:block>} object. If omitted, the block for the current frame |
| 2171 | is used. The optional @var{domain} argument restricts |
| 2172 | the search to the domain type. The @var{domain} argument must be a |
| 2173 | domain constant defined in the @code{(gdb)} module and described later |
| 2174 | in this chapter. |
| 2175 | |
| 2176 | The result is a list of two elements. |
| 2177 | The first element is a @code{<gdb:symbol>} object or @code{#f} if the symbol |
| 2178 | is not found. |
| 2179 | If the symbol is found, the second element is @code{#t} if the symbol |
| 2180 | is a field of a method's object (e.g., @code{this} in C@t{++}), |
| 2181 | otherwise it is @code{#f}. |
| 2182 | If the symbol is not found, the second element is @code{#f}. |
| 2183 | @end deffn |
| 2184 | |
| 2185 | @deffn {Scheme Procedure} lookup-global-symbol name @r{[}#:domain domain@r{]} |
| 2186 | This function searches for a global symbol by name. |
| 2187 | The search scope can be restricted by the domain argument. |
| 2188 | |
| 2189 | @var{name} is the name of the symbol. It must be a string. |
| 2190 | The optional @var{domain} argument restricts the search to the domain type. |
| 2191 | The @var{domain} argument must be a domain constant defined in the @code{(gdb)} |
| 2192 | module and described later in this chapter. |
| 2193 | |
| 2194 | The result is a @code{<gdb:symbol>} object or @code{#f} if the symbol |
| 2195 | is not found. |
| 2196 | @end deffn |
| 2197 | |
| 2198 | The available domain categories in @code{<gdb:symbol>} are represented |
| 2199 | as constants in the @code{(gdb)} module: |
| 2200 | |
| 2201 | @vtable @code |
| 2202 | @item SYMBOL_UNDEF_DOMAIN |
| 2203 | This is used when a domain has not been discovered or none of the |
| 2204 | following domains apply. This usually indicates an error either |
| 2205 | in the symbol information or in @value{GDBN}'s handling of symbols. |
| 2206 | |
| 2207 | @item SYMBOL_VAR_DOMAIN |
| 2208 | This domain contains variables, function names, typedef names and enum |
| 2209 | type values. |
| 2210 | |
| 2211 | @item SYMBOL_STRUCT_DOMAIN |
| 2212 | This domain holds struct, union and enum type names. |
| 2213 | |
| 2214 | @item SYMBOL_LABEL_DOMAIN |
| 2215 | This domain contains names of labels (for gotos). |
| 2216 | |
| 2217 | @item SYMBOL_VARIABLES_DOMAIN |
| 2218 | This domain holds a subset of the @code{SYMBOLS_VAR_DOMAIN}; it |
| 2219 | contains everything minus functions and types. |
| 2220 | |
| 2221 | @item SYMBOL_FUNCTION_DOMAIN |
| 2222 | This domain contains all functions. |
| 2223 | |
| 2224 | @item SYMBOL_TYPES_DOMAIN |
| 2225 | This domain contains all types. |
| 2226 | @end vtable |
| 2227 | |
| 2228 | The available address class categories in @code{<gdb:symbol>} are represented |
| 2229 | as constants in the @code{gdb} module: |
| 2230 | |
| 2231 | @vtable @code |
| 2232 | @item SYMBOL_LOC_UNDEF |
| 2233 | If this is returned by address class, it indicates an error either in |
| 2234 | the symbol information or in @value{GDBN}'s handling of symbols. |
| 2235 | |
| 2236 | @item SYMBOL_LOC_CONST |
| 2237 | Value is constant int. |
| 2238 | |
| 2239 | @item SYMBOL_LOC_STATIC |
| 2240 | Value is at a fixed address. |
| 2241 | |
| 2242 | @item SYMBOL_LOC_REGISTER |
| 2243 | Value is in a register. |
| 2244 | |
| 2245 | @item SYMBOL_LOC_ARG |
| 2246 | Value is an argument. This value is at the offset stored within the |
| 2247 | symbol inside the frame's argument list. |
| 2248 | |
| 2249 | @item SYMBOL_LOC_REF_ARG |
| 2250 | Value address is stored in the frame's argument list. Just like |
| 2251 | @code{LOC_ARG} except that the value's address is stored at the |
| 2252 | offset, not the value itself. |
| 2253 | |
| 2254 | @item SYMBOL_LOC_REGPARM_ADDR |
| 2255 | Value is a specified register. Just like @code{LOC_REGISTER} except |
| 2256 | the register holds the address of the argument instead of the argument |
| 2257 | itself. |
| 2258 | |
| 2259 | @item SYMBOL_LOC_LOCAL |
| 2260 | Value is a local variable. |
| 2261 | |
| 2262 | @item SYMBOL_LOC_TYPEDEF |
| 2263 | Value not used. Symbols in the domain @code{SYMBOL_STRUCT_DOMAIN} all |
| 2264 | have this class. |
| 2265 | |
| 2266 | @item SYMBOL_LOC_BLOCK |
| 2267 | Value is a block. |
| 2268 | |
| 2269 | @item SYMBOL_LOC_CONST_BYTES |
| 2270 | Value is a byte-sequence. |
| 2271 | |
| 2272 | @item SYMBOL_LOC_UNRESOLVED |
| 2273 | Value is at a fixed address, but the address of the variable has to be |
| 2274 | determined from the minimal symbol table whenever the variable is |
| 2275 | referenced. |
| 2276 | |
| 2277 | @item SYMBOL_LOC_OPTIMIZED_OUT |
| 2278 | The value does not actually exist in the program. |
| 2279 | |
| 2280 | @item SYMBOL_LOC_COMPUTED |
| 2281 | The value's address is a computed location. |
| 2282 | @end vtable |
| 2283 | |
| 2284 | @node Symbol Tables In Guile |
| 2285 | @subsubsection Symbol table representation in Guile. |
| 2286 | |
| 2287 | @cindex symbol tables in guile |
| 2288 | @tindex <gdb:symtab> |
| 2289 | @tindex <gdb:sal> |
| 2290 | |
| 2291 | Access to symbol table data maintained by @value{GDBN} on the inferior |
| 2292 | is exposed to Guile via two objects: @code{<gdb:sal>} (symtab-and-line) and |
| 2293 | @code{<gdb:symtab>}. Symbol table and line data for a frame is returned |
| 2294 | from the @code{frame-find-sal} @code{<gdb:frame>} procedure. |
| 2295 | @xref{Frames In Guile}. |
| 2296 | |
| 2297 | For more information on @value{GDBN}'s symbol table management, see |
| 2298 | @ref{Symbols, ,Examining the Symbol Table}. |
| 2299 | |
| 2300 | The following symtab-related procedures are provided by the |
| 2301 | @code{(gdb)} module: |
| 2302 | |
| 2303 | @deffn {Scheme Procedure} symtab? object |
| 2304 | Return @code{#t} if @var{object} is an object of type @code{<gdb:symtab>}. |
| 2305 | Otherwise return @code{#f}. |
| 2306 | @end deffn |
| 2307 | |
| 2308 | @deffn {Scheme Procedure} symtab-valid? symtab |
| 2309 | Return @code{#t} if the @code{<gdb:symtab>} object is valid, |
| 2310 | @code{#f} if not. A @code{<gdb:symtab>} object becomes invalid when |
| 2311 | the symbol table it refers to no longer exists in @value{GDBN}. |
| 2312 | All other @code{<gdb:symtab>} procedures will throw an exception |
| 2313 | if it is invalid at the time the procedure is called. |
| 2314 | @end deffn |
| 2315 | |
| 2316 | @deffn {Scheme Procedure} symtab-filename symtab |
| 2317 | Return the symbol table's source filename. |
| 2318 | @end deffn |
| 2319 | |
| 2320 | @deffn {Scheme Procedure} symtab-fullname symtab |
| 2321 | Return the symbol table's source absolute file name. |
| 2322 | @end deffn |
| 2323 | |
| 2324 | @deffn {Scheme Procedure} symtab-objfile symtab |
| 2325 | Return the symbol table's backing object file. @xref{Objfiles In Guile}. |
| 2326 | @end deffn |
| 2327 | |
| 2328 | @deffn {Scheme Procedure} symtab-global-block symtab |
| 2329 | Return the global block of the underlying symbol table. |
| 2330 | @xref{Blocks In Guile}. |
| 2331 | @end deffn |
| 2332 | |
| 2333 | @deffn {Scheme Procedure} symtab-static-block symtab |
| 2334 | Return the static block of the underlying symbol table. |
| 2335 | @xref{Blocks In Guile}. |
| 2336 | @end deffn |
| 2337 | |
| 2338 | The following symtab-and-line-related procedures are provided by the |
| 2339 | @code{(gdb)} module: |
| 2340 | |
| 2341 | @deffn {Scheme Procedure} sal? object |
| 2342 | Return @code{#t} if @var{object} is an object of type @code{<gdb:sal>}. |
| 2343 | Otherwise return @code{#f}. |
| 2344 | @end deffn |
| 2345 | |
| 2346 | @deffn {Scheme Procedure} sal-valid? sal |
| 2347 | Return @code{#t} if @var{sal} is valid, @code{#f} if not. |
| 2348 | A @code{<gdb:sal>} object becomes invalid when the Symbol table object |
| 2349 | it refers to no longer exists in @value{GDBN}. All other |
| 2350 | @code{<gdb:sal>} procedures will throw an exception if it is |
| 2351 | invalid at the time the procedure is called. |
| 2352 | @end deffn |
| 2353 | |
| 2354 | @deffn {Scheme Procedure} sal-symtab sal |
| 2355 | Return the symbol table object (@code{<gdb:symtab>}) for @var{sal}. |
| 2356 | @end deffn |
| 2357 | |
| 2358 | @deffn {Scheme Procedure} sal-line sal |
| 2359 | Return the line number for @var{sal}. |
| 2360 | @end deffn |
| 2361 | |
| 2362 | @deffn {Scheme Procedure} sal-pc sal |
| 2363 | Return the start of the address range occupied by code for @var{sal}. |
| 2364 | @end deffn |
| 2365 | |
| 2366 | @deffn {Scheme Procedure} sal-last sal |
| 2367 | Return the end of the address range occupied by code for @var{sal}. |
| 2368 | @end deffn |
| 2369 | |
| 2370 | @deffn {Scheme Procedure} find-pc-line pc |
| 2371 | Return the @code{<gdb:sal>} object corresponding to the @var{pc} value. |
| 2372 | If an invalid value of @var{pc} is passed as an argument, then the |
| 2373 | @code{symtab} and @code{line} attributes of the returned @code{<gdb:sal>} |
| 2374 | object will be @code{#f} and 0 respectively. |
| 2375 | @end deffn |
| 2376 | |
| 2377 | @node Breakpoints In Guile |
| 2378 | @subsubsection Manipulating breakpoints using Guile |
| 2379 | |
| 2380 | @cindex breakpoints in guile |
| 2381 | @tindex <gdb:breakpoint> |
| 2382 | |
| 2383 | Breakpoints in Guile are represented by objects of type |
| 2384 | @code{<gdb:breakpoint>}. |
| 2385 | |
| 2386 | The following breakpoint-related procedures are provided by the |
| 2387 | @code{(gdb)} module: |
| 2388 | |
| 2389 | @c TODO: line length |
| 2390 | @deffn {Scheme Procedure} create-breakpoint! location @r{[}#:type type@r{]} @r{[}#:wp-class wp-class@r{]} @r{[}#:internal internal@r{]} |
| 2391 | Create a new breakpoint. @var{spec} is a string naming the |
| 2392 | location of the breakpoint, or an expression that defines a watchpoint. |
| 2393 | The contents can be any location recognized by the @code{break} command, |
| 2394 | or in the case of a watchpoint, by the @code{watch} command. |
| 2395 | |
| 2396 | The optional @var{type} denotes the breakpoint to create. |
| 2397 | This argument can be either: @code{BP_BREAKPOINT} or @code{BP_WATCHPOINT}. |
| 2398 | @var{type} defaults to @code{BP_BREAKPOINT}. |
| 2399 | |
| 2400 | The optional @var{wp-class} argument defines the class of watchpoint to |
| 2401 | create, if @var{type} is @code{BP_WATCHPOINT}. If a watchpoint class is |
| 2402 | not provided, it is assumed to be a @code{WP_WRITE} class. |
| 2403 | |
| 2404 | The optional @var{internal} argument allows the breakpoint to become |
| 2405 | invisible to the user. The breakpoint will neither be reported when |
| 2406 | created, nor will it be listed in the output from @code{info breakpoints} |
| 2407 | (but will be listed with the @code{maint info breakpoints} command). |
| 2408 | If an internal flag is not provided, the breakpoint is visible |
| 2409 | (non-internal). |
| 2410 | |
| 2411 | When a watchpoint is created, @value{GDBN} will try to create a |
| 2412 | hardware assisted watchpoint. If successful, the type of the watchpoint |
| 2413 | is changed from @code{BP_WATCHPOINT} to @code{BP_HARDWARE_WATCHPOINT} |
| 2414 | for @code{WP_WRITE}, @code{BP_READ_WATCHPOINT} for @code{WP_READ}, |
| 2415 | and @code{BP_ACCESS_WATCHPOINT} for @code{WP_ACCESS}. |
| 2416 | If not successful, the type of the watchpoint is left as @code{WP_WATCHPOINT}. |
| 2417 | |
| 2418 | The available types are represented by constants defined in the @code{gdb} |
| 2419 | module: |
| 2420 | |
| 2421 | @vtable @code |
| 2422 | @item BP_BREAKPOINT |
| 2423 | Normal code breakpoint. |
| 2424 | |
| 2425 | @item BP_WATCHPOINT |
| 2426 | Watchpoint breakpoint. |
| 2427 | |
| 2428 | @item BP_HARDWARE_WATCHPOINT |
| 2429 | Hardware assisted watchpoint. |
| 2430 | This value cannot be specified when creating the breakpoint. |
| 2431 | |
| 2432 | @item BP_READ_WATCHPOINT |
| 2433 | Hardware assisted read watchpoint. |
| 2434 | This value cannot be specified when creating the breakpoint. |
| 2435 | |
| 2436 | @item BP_ACCESS_WATCHPOINT |
| 2437 | Hardware assisted access watchpoint. |
| 2438 | This value cannot be specified when creating the breakpoint. |
| 2439 | @end vtable |
| 2440 | |
| 2441 | The available watchpoint types represented by constants are defined in the |
| 2442 | @code{(gdb)} module: |
| 2443 | |
| 2444 | @vtable @code |
| 2445 | @item WP_READ |
| 2446 | Read only watchpoint. |
| 2447 | |
| 2448 | @item WP_WRITE |
| 2449 | Write only watchpoint. |
| 2450 | |
| 2451 | @item WP_ACCESS |
| 2452 | Read/Write watchpoint. |
| 2453 | @end vtable |
| 2454 | |
| 2455 | @end deffn |
| 2456 | |
| 2457 | @deffn {Scheme Procedure} breakpoint-delete! breakpoint |
| 2458 | Permanently delete @var{breakpoint}. This also invalidates the |
| 2459 | Guile @var{breakpoint} object. Any further attempt to access the |
| 2460 | object will throw an exception. |
| 2461 | @end deffn |
| 2462 | |
| 2463 | @deffn {Scheme Procedure} breakpoints |
| 2464 | Return a list of all breakpoints. |
| 2465 | Each element of the list is a @code{<gdb:breakpoint>} object. |
| 2466 | @end deffn |
| 2467 | |
| 2468 | @deffn {Scheme Procedure} breakpoint? object |
| 2469 | Return @code{#t} if @var{object} is a @code{<gdb:breakpoint>} object, |
| 2470 | and @code{#f} otherwise. |
| 2471 | @end deffn |
| 2472 | |
| 2473 | @deffn {Scheme Procedure} breakpoint-valid? breakpoint |
| 2474 | Return @code{#t} if @var{breakpoint} is valid, @code{#f} otherwise. |
| 2475 | A @code{<gdb:breakpoint>} object can become invalid |
| 2476 | if the user deletes the breakpoint. In this case, the object still |
| 2477 | exists, but the underlying breakpoint does not. In the cases of |
| 2478 | watchpoint scope, the watchpoint remains valid even if execution of the |
| 2479 | inferior leaves the scope of that watchpoint. |
| 2480 | @end deffn |
| 2481 | |
| 2482 | @deffn {Scheme Procedure} breakpoint-number breakpoint |
| 2483 | Return the breakpoint's number --- the identifier used by |
| 2484 | the user to manipulate the breakpoint. |
| 2485 | @end deffn |
| 2486 | |
| 2487 | @deffn {Scheme Procedure} breakpoint-type breakpoint |
| 2488 | Return the breakpoint's type --- the identifier used to |
| 2489 | determine the actual breakpoint type or use-case. |
| 2490 | @end deffn |
| 2491 | |
| 2492 | @deffn {Scheme Procedure} breakpoint-visible? breakpoint |
| 2493 | Return @code{#t} if the breakpoint is visible to the user |
| 2494 | when hit, or when the @samp{info breakpoints} command is run. |
| 2495 | Otherwise return @code{#f}. |
| 2496 | @end deffn |
| 2497 | |
| 2498 | @deffn {Scheme Procedure} breakpoint-location breakpoint |
| 2499 | Return the location of the breakpoint, as specified by |
| 2500 | the user. It is a string. If the breakpoint does not have a location |
| 2501 | (that is, it is a watchpoint) return @code{#f}. |
| 2502 | @end deffn |
| 2503 | |
| 2504 | @deffn {Scheme Procedure} breakpoint-expression breakpoint |
| 2505 | Return the breakpoint expression, as specified by the user. It is a string. |
| 2506 | If the breakpoint does not have an expression (the breakpoint is not a |
| 2507 | watchpoint) return @code{#f}. |
| 2508 | @end deffn |
| 2509 | |
| 2510 | @deffn {Scheme Procedure} breakpoint-enabled? breakpoint |
| 2511 | Return @code{#t} if the breakpoint is enabled, and @code{#f} otherwise. |
| 2512 | @end deffn |
| 2513 | |
| 2514 | @deffn {Scheme Procedure} set-breakpoint-enabled! breakpoint flag |
| 2515 | Set the enabled state of @var{breakpoint} to @var{flag}. |
| 2516 | If flag is @code{#f} it is disabled, otherwise it is enabled. |
| 2517 | @end deffn |
| 2518 | |
| 2519 | @deffn {Scheme Procedure} breakpoint-silent? breakpoint |
| 2520 | Return @code{#t} if the breakpoint is silent, and @code{#f} otherwise. |
| 2521 | |
| 2522 | Note that a breakpoint can also be silent if it has commands and the |
| 2523 | first command is @code{silent}. This is not reported by the |
| 2524 | @code{silent} attribute. |
| 2525 | @end deffn |
| 2526 | |
| 2527 | @deffn {Scheme Procedure} set-breakpoint-silent! breakpoint flag |
| 2528 | Set the silent state of @var{breakpoint} to @var{flag}. |
| 2529 | If flag is @code{#f} the breakpoint is made silent, |
| 2530 | otherwise it is made non-silent (or noisy). |
| 2531 | @end deffn |
| 2532 | |
| 2533 | @deffn {Scheme Procedure} breakpoint-ignore-count breakpoint |
| 2534 | Return the ignore count for @var{breakpoint}. |
| 2535 | @end deffn |
| 2536 | |
| 2537 | @deffn {Scheme Procedure} set-breakpoint-ignore-count! breakpoint count |
| 2538 | Set the ignore count for @var{breakpoint} to @var{count}. |
| 2539 | @end deffn |
| 2540 | |
| 2541 | @deffn {Scheme Procedure} breakpoint-hit-count breakpoint |
| 2542 | Return hit count of @var{breakpoint}. |
| 2543 | @end deffn |
| 2544 | |
| 2545 | @deffn {Scheme Procedure} set-breakpoint-hit-count! breakpoint count |
| 2546 | Set the hit count of @var{breakpoint} to @var{count}. |
| 2547 | At present, @var{count} must be zero. |
| 2548 | @end deffn |
| 2549 | |
| 2550 | @deffn {Scheme Procedure} breakpoint-thread breakpoint |
| 2551 | Return the thread-id for thread-specific breakpoint @var{breakpoint}. |
| 2552 | Return #f if @var{breakpoint} is not thread-specific. |
| 2553 | @end deffn |
| 2554 | |
| 2555 | @deffn {Scheme Procedure} set-breakpoint-thread! breakpoint thread-id|#f |
| 2556 | Set the thread-id for @var{breakpoint} to @var{thread-id}. |
| 2557 | If set to @code{#f}, the breakpoint is no longer thread-specific. |
| 2558 | @end deffn |
| 2559 | |
| 2560 | @deffn {Scheme Procedure} breakpoint-task breakpoint |
| 2561 | If the breakpoint is Ada task-specific, return the Ada task id. |
| 2562 | If the breakpoint is not task-specific (or the underlying |
| 2563 | language is not Ada), return @code{#f}. |
| 2564 | @end deffn |
| 2565 | |
| 2566 | @deffn {Scheme Procedure} set-breakpoint-task! breakpoint task |
| 2567 | Set the Ada task of @var{breakpoint} to @var{task}. |
| 2568 | If set to @code{#f}, the breakpoint is no longer task-specific. |
| 2569 | @end deffn |
| 2570 | |
| 2571 | @deffn {Scheme Procedure} breakpoint-condition breakpoint |
| 2572 | Return the condition of @var{breakpoint}, as specified by the user. |
| 2573 | It is a string. If there is no condition, return @code{#f}. |
| 2574 | @end deffn |
| 2575 | |
| 2576 | @deffn {Scheme Procedure} set-breakpoint-condition! breakpoint condition |
| 2577 | Set the condition of @var{breakpoint} to @var{condition}, |
| 2578 | which must be a string. If set to @code{#f} then the breakpoint |
| 2579 | becomes unconditional. |
| 2580 | @end deffn |
| 2581 | |
| 2582 | @deffn {Scheme Procedure} breakpoint-stop breakpoint |
| 2583 | Return the stop predicate of @var{breakpoint}. |
| 2584 | See @code{set-breakpoint-stop!} below in this section. |
| 2585 | @end deffn |
| 2586 | |
| 2587 | @deffn {Scheme Procedure} set-breakpoint-stop! breakpoint procedure|#f |
| 2588 | Set the stop predicate of @var{breakpoint}. |
| 2589 | @var{procedure} takes one argument: the <gdb:breakpoint> object. |
| 2590 | If this predicate is set to a procedure then it is invoked whenever |
| 2591 | the inferior reaches this breakpoint. If it returns @code{#t}, |
| 2592 | or any non-@code{#f} value, then the inferior is stopped, |
| 2593 | otherwise the inferior will continue. |
| 2594 | |
| 2595 | If there are multiple breakpoints at the same location with a |
| 2596 | @code{stop} predicate, each one will be called regardless of the |
| 2597 | return status of the previous. This ensures that all @code{stop} |
| 2598 | predicates have a chance to execute at that location. In this scenario |
| 2599 | if one of the methods returns @code{#t} but the others return |
| 2600 | @code{#f}, the inferior will still be stopped. |
| 2601 | |
| 2602 | You should not alter the execution state of the inferior (i.e.@:, step, |
| 2603 | next, etc.), alter the current frame context (i.e.@:, change the current |
| 2604 | active frame), or alter, add or delete any breakpoint. As a general |
| 2605 | rule, you should not alter any data within @value{GDBN} or the inferior |
| 2606 | at this time. |
| 2607 | |
| 2608 | Example @code{stop} implementation: |
| 2609 | |
| 2610 | @smallexample |
| 2611 | (define (my-stop? bkpt) |
| 2612 | (let ((int-val (parse-and-eval "foo"))) |
| 2613 | (value=? int-val 3))) |
| 2614 | (define bkpt (create-breakpoint! "main.c:42")) |
| 2615 | (set-breakpoint-stop! bkpt my-stop?) |
| 2616 | @end smallexample |
| 2617 | @end deffn |
| 2618 | |
| 2619 | @deffn {Scheme Procedure} breakpoint-commands breakpoint |
| 2620 | Return the commands attached to @var{breakpoint} as a string, |
| 2621 | or @code{#f} if there are none. |
| 2622 | @end deffn |
| 2623 | |
| 2624 | @node Lazy Strings In Guile |
| 2625 | @subsubsection Guile representation of lazy strings. |
| 2626 | |
| 2627 | @cindex lazy strings in guile |
| 2628 | @tindex <gdb:lazy-string> |
| 2629 | |
| 2630 | A @dfn{lazy string} is a string whose contents is not retrieved or |
| 2631 | encoded until it is needed. |
| 2632 | |
| 2633 | A @code{<gdb:lazy-string>} is represented in @value{GDBN} as an |
| 2634 | @code{address} that points to a region of memory, an @code{encoding} |
| 2635 | that will be used to encode that region of memory, and a @code{length} |
| 2636 | to delimit the region of memory that represents the string. The |
| 2637 | difference between a @code{<gdb:lazy-string>} and a string wrapped within |
| 2638 | a @code{<gdb:value>} is that a @code{<gdb:lazy-string>} will be treated |
| 2639 | differently by @value{GDBN} when printing. A @code{<gdb:lazy-string>} is |
| 2640 | retrieved and encoded during printing, while a @code{<gdb:value>} |
| 2641 | wrapping a string is immediately retrieved and encoded on creation. |
| 2642 | |
| 2643 | The following lazy-string-related procedures are provided by the |
| 2644 | @code{(gdb)} module: |
| 2645 | |
| 2646 | @deffn {Scheme Procedure} lazy-string? object |
| 2647 | Return @code{#t} if @var{object} is an object of type @code{<gdb:lazy-string>}. |
| 2648 | Otherwise return @code{#f}. |
| 2649 | @end deffn |
| 2650 | |
| 2651 | @deffn {Scheme Procedure} lazy-string-address lazy-sring |
| 2652 | Return the address of @var{lazy-string}. |
| 2653 | @end deffn |
| 2654 | |
| 2655 | @deffn {Scheme Procedure} lazy-string-length lazy-string |
| 2656 | Return the length of @var{lazy-string} in characters. If the |
| 2657 | length is -1, then the string will be fetched and encoded up to the |
| 2658 | first null of appropriate width. |
| 2659 | @end deffn |
| 2660 | |
| 2661 | @deffn {Scheme Procedure} lazy-string-encoding lazy-string |
| 2662 | Return the encoding that will be applied to @var{lazy-string} |
| 2663 | when the string is printed by @value{GDBN}. If the encoding is not |
| 2664 | set, or contains an empty string, then @value{GDBN} will select the |
| 2665 | most appropriate encoding when the string is printed. |
| 2666 | @end deffn |
| 2667 | |
| 2668 | @deffn {Scheme Procedure} lazy-string-type lazy-string |
| 2669 | Return the type that is represented by @var{lazy-string}'s type. |
| 2670 | For a lazy string this will always be a pointer type. To |
| 2671 | resolve this to the lazy string's character type, use @code{type-target-type}. |
| 2672 | @xref{Types In Guile}. |
| 2673 | @end deffn |
| 2674 | |
| 2675 | @deffn {Scheme Procedure} lazy-string->value lazy-string |
| 2676 | Convert the @code{<gdb:lazy-string>} to a @code{<gdb:value>}. This value |
| 2677 | will point to the string in memory, but will lose all the delayed |
| 2678 | retrieval, encoding and handling that @value{GDBN} applies to a |
| 2679 | @code{<gdb:lazy-string>}. |
| 2680 | @end deffn |
| 2681 | |
| 2682 | @node Architectures In Guile |
| 2683 | @subsubsection Guile representation of architectures |
| 2684 | |
| 2685 | @cindex guile architectures |
| 2686 | @tindex <gdb:arch> |
| 2687 | |
| 2688 | @value{GDBN} uses architecture specific parameters and artifacts in a |
| 2689 | number of its various computations. An architecture is represented |
| 2690 | by an instance of the @code{<gdb:arch>} class. |
| 2691 | |
| 2692 | The following architecture-related procedures are provided by the |
| 2693 | @code{(gdb)} module: |
| 2694 | |
| 2695 | @deffn {Scheme Procedure} arch? object |
| 2696 | Return @code{#t} if @var{object} is an object of type @code{<gdb:arch>}. |
| 2697 | Otherwise return @code{#f}. |
| 2698 | @end deffn |
| 2699 | |
| 2700 | @deffn {Scheme Procedure} current-arch |
| 2701 | Return the current architecture as a @code{<gdb:arch>} object. |
| 2702 | @end deffn |
| 2703 | |
| 2704 | @deffn {Scheme Procedure} arch-name arch |
| 2705 | Return the name (string value) of @code{<gdb:arch>} @var{arch}. |
| 2706 | @end deffn |
| 2707 | |
| 2708 | @deffn {Scheme Procedure} arch-charset arch |
| 2709 | Return name of target character set of @code{<gdb:arch>} @var{arch}. |
| 2710 | @end deffn |
| 2711 | |
| 2712 | @deffn {Scheme Procedure} arch-wide-charset |
| 2713 | Return name of target wide character set of @code{<gdb:arch>} @var{arch}. |
| 2714 | @end deffn |
| 2715 | |
| 2716 | Each architecture provides a set of predefined types, obtained by |
| 2717 | the following functions. |
| 2718 | |
| 2719 | @deffn {Scheme Procedure} arch-void-type arch |
| 2720 | Return the @code{<gdb:type>} object for a @code{void} type |
| 2721 | of architecture @var{arch}. |
| 2722 | @end deffn |
| 2723 | |
| 2724 | @deffn {Scheme Procedure} arch-char-type arch |
| 2725 | Return the @code{<gdb:type>} object for a @code{char} type |
| 2726 | of architecture @var{arch}. |
| 2727 | @end deffn |
| 2728 | |
| 2729 | @deffn {Scheme Procedure} arch-short-type arch |
| 2730 | Return the @code{<gdb:type>} object for a @code{short} type |
| 2731 | of architecture @var{arch}. |
| 2732 | @end deffn |
| 2733 | |
| 2734 | @deffn {Scheme Procedure} arch-int-type arch |
| 2735 | Return the @code{<gdb:type>} object for an @code{int} type |
| 2736 | of architecture @var{arch}. |
| 2737 | @end deffn |
| 2738 | |
| 2739 | @deffn {Scheme Procedure} arch-long-type arch |
| 2740 | Return the @code{<gdb:type>} object for a @code{long} type |
| 2741 | of architecture @var{arch}. |
| 2742 | @end deffn |
| 2743 | |
| 2744 | @deffn {Scheme Procedure} arch-schar-type arch |
| 2745 | Return the @code{<gdb:type>} object for a @code{signed char} type |
| 2746 | of architecture @var{arch}. |
| 2747 | @end deffn |
| 2748 | |
| 2749 | @deffn {Scheme Procedure} arch-uchar-type arch |
| 2750 | Return the @code{<gdb:type>} object for an @code{unsigned char} type |
| 2751 | of architecture @var{arch}. |
| 2752 | @end deffn |
| 2753 | |
| 2754 | @deffn {Scheme Procedure} arch-ushort-type arch |
| 2755 | Return the @code{<gdb:type>} object for an @code{unsigned short} type |
| 2756 | of architecture @var{arch}. |
| 2757 | @end deffn |
| 2758 | |
| 2759 | @deffn {Scheme Procedure} arch-uint-type arch |
| 2760 | Return the @code{<gdb:type>} object for an @code{unsigned int} type |
| 2761 | of architecture @var{arch}. |
| 2762 | @end deffn |
| 2763 | |
| 2764 | @deffn {Scheme Procedure} arch-ulong-type arch |
| 2765 | Return the @code{<gdb:type>} object for an @code{unsigned long} type |
| 2766 | of architecture @var{arch}. |
| 2767 | @end deffn |
| 2768 | |
| 2769 | @deffn {Scheme Procedure} arch-float-type arch |
| 2770 | Return the @code{<gdb:type>} object for a @code{float} type |
| 2771 | of architecture @var{arch}. |
| 2772 | @end deffn |
| 2773 | |
| 2774 | @deffn {Scheme Procedure} arch-double-type arch |
| 2775 | Return the @code{<gdb:type>} object for a @code{double} type |
| 2776 | of architecture @var{arch}. |
| 2777 | @end deffn |
| 2778 | |
| 2779 | @deffn {Scheme Procedure} arch-longdouble-type arch |
| 2780 | Return the @code{<gdb:type>} object for a @code{long double} type |
| 2781 | of architecture @var{arch}. |
| 2782 | @end deffn |
| 2783 | |
| 2784 | @deffn {Scheme Procedure} arch-bool-type arch |
| 2785 | Return the @code{<gdb:type>} object for a @code{bool} type |
| 2786 | of architecture @var{arch}. |
| 2787 | @end deffn |
| 2788 | |
| 2789 | @deffn {Scheme Procedure} arch-longlong-type arch |
| 2790 | Return the @code{<gdb:type>} object for a @code{long long} type |
| 2791 | of architecture @var{arch}. |
| 2792 | @end deffn |
| 2793 | |
| 2794 | @deffn {Scheme Procedure} arch-ulonglong-type arch |
| 2795 | Return the @code{<gdb:type>} object for an @code{unsigned long long} type |
| 2796 | of architecture @var{arch}. |
| 2797 | @end deffn |
| 2798 | |
| 2799 | @deffn {Scheme Procedure} arch-int8-type arch |
| 2800 | Return the @code{<gdb:type>} object for an @code{int8} type |
| 2801 | of architecture @var{arch}. |
| 2802 | @end deffn |
| 2803 | |
| 2804 | @deffn {Scheme Procedure} arch-uint8-type arch |
| 2805 | Return the @code{<gdb:type>} object for a @code{uint8} type |
| 2806 | of architecture @var{arch}. |
| 2807 | @end deffn |
| 2808 | |
| 2809 | @deffn {Scheme Procedure} arch-int16-type arch |
| 2810 | Return the @code{<gdb:type>} object for an @code{int16} type |
| 2811 | of architecture @var{arch}. |
| 2812 | @end deffn |
| 2813 | |
| 2814 | @deffn {Scheme Procedure} arch-uint16-type arch |
| 2815 | Return the @code{<gdb:type>} object for a @code{uint16} type |
| 2816 | of architecture @var{arch}. |
| 2817 | @end deffn |
| 2818 | |
| 2819 | @deffn {Scheme Procedure} arch-int32-type arch |
| 2820 | Return the @code{<gdb:type>} object for an @code{int32} type |
| 2821 | of architecture @var{arch}. |
| 2822 | @end deffn |
| 2823 | |
| 2824 | @deffn {Scheme Procedure} arch-uint32-type arch |
| 2825 | Return the @code{<gdb:type>} object for a @code{uint32} type |
| 2826 | of architecture @var{arch}. |
| 2827 | @end deffn |
| 2828 | |
| 2829 | @deffn {Scheme Procedure} arch-int64-type arch |
| 2830 | Return the @code{<gdb:type>} object for an @code{int64} type |
| 2831 | of architecture @var{arch}. |
| 2832 | @end deffn |
| 2833 | |
| 2834 | @deffn {Scheme Procedure} arch-uint64-type arch |
| 2835 | Return the @code{<gdb:type>} object for a @code{uint64} type |
| 2836 | of architecture @var{arch}. |
| 2837 | @end deffn |
| 2838 | |
| 2839 | Example: |
| 2840 | |
| 2841 | @smallexample |
| 2842 | (gdb) guile (type-name (arch-uchar-type (current-arch))) |
| 2843 | "unsigned char" |
| 2844 | @end smallexample |
| 2845 | |
| 2846 | @node Disassembly In Guile |
| 2847 | @subsubsection Disassembly In Guile |
| 2848 | |
| 2849 | The disassembler can be invoked from Scheme code. |
| 2850 | Furthermore, the disassembler can take a Guile port as input, |
| 2851 | allowing one to disassemble from any source, and not just target memory. |
| 2852 | |
| 2853 | @c TODO: line length |
| 2854 | @deffn {Scheme Procedure} arch-disassemble arch start-pc @r{[}#:port port@r{]} @r{[}#:offset offset@r{]} @r{[}#:size size@r{]} @r{[}#:count count@r{]} |
| 2855 | Return a list of disassembled instructions starting from the memory |
| 2856 | address @var{start-pc}. |
| 2857 | |
| 2858 | The optional argument @var{port} specifies the input port to read bytes from. |
| 2859 | If @var{port} is @code{#f} then bytes are read from target memory. |
| 2860 | |
| 2861 | The optional argument @var{offset} specifies the address offset of the |
| 2862 | first byte in @var{port}. This is useful, for example, when @var{port} |
| 2863 | specifies a @samp{bytevector} and you want the bytevector to be disassembled |
| 2864 | as if it came from that address. The @var{start-pc} passed to the reader |
| 2865 | for @var{port} is offset by the same amount. |
| 2866 | |
| 2867 | Example: |
| 2868 | @smallexample |
| 2869 | (gdb) guile (use-modules (rnrs io ports)) |
| 2870 | (gdb) guile (define pc (value->integer (parse-and-eval "$pc"))) |
| 2871 | (gdb) guile (define mem (open-memory #:start pc)) |
| 2872 | (gdb) guile (define bv (get-bytevector-n mem 10)) |
| 2873 | (gdb) guile (define bv-port (open-bytevector-input-port bv)) |
| 2874 | (gdb) guile (define arch (current-arch)) |
| 2875 | (gdb) guile (arch-disassemble arch pc #:port bv-port #:offset pc) |
| 2876 | (((address . 4195516) (asm . "mov $0x4005c8,%edi") (length . 5))) |
| 2877 | @end smallexample |
| 2878 | |
| 2879 | The optional arguments @var{size} and |
| 2880 | @var{count} determine the number of instructions in the returned list. |
| 2881 | If either @var{size} or @var{count} is specified as zero, then |
| 2882 | no instructions are disassembled and an empty list is returned. |
| 2883 | If both the optional arguments @var{size} and @var{count} are |
| 2884 | specified, then a list of at most @var{count} disassembled instructions |
| 2885 | whose start address falls in the closed memory address interval from |
| 2886 | @var{start-pc} to (@var{start-pc} + @var{size} - 1) are returned. |
| 2887 | If @var{size} is not specified, but @var{count} is specified, |
| 2888 | then @var{count} number of instructions starting from the address |
| 2889 | @var{start-pc} are returned. If @var{count} is not specified but |
| 2890 | @var{size} is specified, then all instructions whose start address |
| 2891 | falls in the closed memory address interval from @var{start-pc} to |
| 2892 | (@var{start-pc} + @var{size} - 1) are returned. |
| 2893 | If neither @var{size} nor @var{count} are specified, then a single |
| 2894 | instruction at @var{start-pc} is returned. |
| 2895 | |
| 2896 | Each element of the returned list is an alist (associative list) |
| 2897 | with the following keys: |
| 2898 | |
| 2899 | @table @code |
| 2900 | |
| 2901 | @item address |
| 2902 | The value corresponding to this key is a Guile integer of |
| 2903 | the memory address of the instruction. |
| 2904 | |
| 2905 | @item asm |
| 2906 | The value corresponding to this key is a string value which represents |
| 2907 | the instruction with assembly language mnemonics. The assembly |
| 2908 | language flavor used is the same as that specified by the current CLI |
| 2909 | variable @code{disassembly-flavor}. @xref{Machine Code}. |
| 2910 | |
| 2911 | @item length |
| 2912 | The value corresponding to this key is the length of the instruction in bytes. |
| 2913 | |
| 2914 | @end table |
| 2915 | @end deffn |
| 2916 | |
| 2917 | @node I/O Ports in Guile |
| 2918 | @subsubsection I/O Ports in Guile |
| 2919 | |
| 2920 | @deffn {Scheme Procedure} input-port |
| 2921 | Return @value{GDBN}'s input port as a Guile port object. |
| 2922 | @end deffn |
| 2923 | |
| 2924 | @deffn {Scheme Procedure} output-port |
| 2925 | Return @value{GDBN}'s output port as a Guile port object. |
| 2926 | @end deffn |
| 2927 | |
| 2928 | @deffn {Scheme Procedure} error-port |
| 2929 | Return @value{GDBN}'s error port as a Guile port object. |
| 2930 | @end deffn |
| 2931 | |
| 2932 | @deffn {Scheme Procedure} stdio-port? object |
| 2933 | Return @code{#t} if @var{object} is a @value{GDBN} stdio port. |
| 2934 | Otherwise return @code{#f}. |
| 2935 | @end deffn |
| 2936 | |
| 2937 | @node Memory Ports in Guile |
| 2938 | @subsubsection Memory Ports in Guile |
| 2939 | |
| 2940 | @value{GDBN} provides a @code{port} interface to target memory. |
| 2941 | This allows Guile code to read/write target memory using Guile's port and |
| 2942 | bytevector functionality. The main routine is @code{open-memory} which |
| 2943 | returns a port object. One can then read/write memory using that object. |
| 2944 | |
| 2945 | @deffn {Scheme Procedure} open-memory @r{[}#:mode mode{]} @r{[}#:start address{]} @r{[}#:size size{]} |
| 2946 | Return a port object that can be used for reading and writing memory. |
| 2947 | @var{mode} is the standard mode argument to Guile port open routines, |
| 2948 | except that it is restricted to one of @samp{"r"}, @samp{"w"}, or @samp{"r+"}. |
| 2949 | For compatibility @samp{"b"} (binary) may also be present, |
| 2950 | but we ignore it: memory ports are binary only. |
| 2951 | The default is @samp{"r"}, read-only. |
| 2952 | |
| 2953 | The chunk of memory that can be accessed can be bounded. |
| 2954 | If both @var{start} and @var{size} are unspecified, all of memory can be |
| 2955 | accessed. If only @var{start} is specified, all of memory from that point |
| 2956 | on can be accessed. If only @var{size} if specified, all memory in the |
| 2957 | range [0,@var{size}) can be accessed. If both are specified, all memory |
| 2958 | in the rane [@var{start},@var{start}+@var{size}) can be accessed. |
| 2959 | @end deffn |
| 2960 | |
| 2961 | @deffn {Scheme Procedure} memory-port? |
| 2962 | Return @code{#t} if @var{object} is an object of type @code{<gdb:memory-port>}. |
| 2963 | Otherwise return @code{#f}. |
| 2964 | @end deffn |
| 2965 | |
| 2966 | @deffn {Scheme Procedure} memory-port-range memory-port |
| 2967 | Return the range of @code{<gdb:memory-port>} @var{memory-port} as a list |
| 2968 | of two elements: @code{(start end)}. The range is @var{start} to @var{end} |
| 2969 | inclusive. |
| 2970 | @end deffn |
| 2971 | |
| 2972 | @deffn {Scheme Procedure} memory-port-read-buffer-size memory-port |
| 2973 | Return the size of the read buffer of @code{<gdb:memory-port>} |
| 2974 | @var{memory-port}. |
| 2975 | @end deffn |
| 2976 | |
| 2977 | @deffn {Scheme Procedure} set-memory-port-read-buffer-size! memory-port size |
| 2978 | Set the size of the read buffer of @code{<gdb:memory-port>} |
| 2979 | @var{memory-port} to @var{size}. The result is unspecified. |
| 2980 | @end deffn |
| 2981 | |
| 2982 | @deffn {Scheme Procedure} memory-port-write-buffer-size memory-port |
| 2983 | Return the size of the write buffer of @code{<gdb:memory-port>} |
| 2984 | @var{memory-port}. |
| 2985 | @end deffn |
| 2986 | |
| 2987 | @deffn {Scheme Procedure} set-memory-port-write-buffer-size! memory-port size |
| 2988 | Set the size of the write buffer of @code{<gdb:memory-port>} |
| 2989 | @var{memory-port} to @var{size}. The result is unspecified. |
| 2990 | @end deffn |
| 2991 | |
| 2992 | A memory port is closed like any other port, with @code{close-port}. |
| 2993 | |
| 2994 | Combined with Guile's @code{bytevectors}, memory ports provide a lot |
| 2995 | of utility. For example, to fill a buffer of 10 integers in memory, |
| 2996 | one can do something like the following. |
| 2997 | |
| 2998 | @smallexample |
| 2999 | ;; In the program: int buffer[10]; |
| 3000 | (use-modules (rnrs bytevectors)) |
| 3001 | (use-modules (rnrs io ports)) |
| 3002 | (define addr (parse-and-eval "buffer")) |
| 3003 | (define n 10) |
| 3004 | (define byte-size (* n 4)) |
| 3005 | (define mem-port (open-memory #:mode "r+" #:start |
| 3006 | (value->integer addr) #:size byte-size)) |
| 3007 | (define byte-vec (make-bytevector byte-size)) |
| 3008 | (do ((i 0 (+ i 1))) |
| 3009 | ((>= i n)) |
| 3010 | (bytevector-s32-native-set! byte-vec (* i 4) (* i 42))) |
| 3011 | (put-bytevector mem-port byte-vec) |
| 3012 | (close-port mem-port) |
| 3013 | @end smallexample |
| 3014 | |
| 3015 | @node Iterators In Guile |
| 3016 | @subsubsection Iterators In Guile |
| 3017 | |
| 3018 | @cindex guile iterators |
| 3019 | @tindex <gdb:iterator> |
| 3020 | |
| 3021 | A simple iterator facility is provided to allow, for example, |
| 3022 | iterating over the set of program symbols without having to first |
| 3023 | construct a list of all of them. A useful contribution would be |
| 3024 | to add support for SRFI 41 and SRFI 45. |
| 3025 | |
| 3026 | @deffn {Scheme Procedure} make-iterator object progress next! |
| 3027 | A @code{<gdb:iterator>} object is constructed with the @code{make-iterator} |
| 3028 | procedure. It takes three arguments: the object to be iterated over, |
| 3029 | an object to record the progress of the iteration, and a procedure to |
| 3030 | return the next element in the iteration, or an implementation chosen value |
| 3031 | to denote the end of iteration. |
| 3032 | |
| 3033 | By convention, end of iteration is marked with @code{(end-of-iteration)}, |
| 3034 | and may be tested with the @code{end-of-iteration?} predicate. |
| 3035 | The result of @code{(end-of-iteration)} is chosen so that it is not |
| 3036 | otherwise used by the @code{(gdb)} module. If you are using |
| 3037 | @code{<gdb:iterator>} in your own code it is your responsibility to |
| 3038 | maintain this invariant. |
| 3039 | |
| 3040 | A trivial example for illustration's sake: |
| 3041 | |
| 3042 | @smallexample |
| 3043 | (use-modules (gdb iterator)) |
| 3044 | (define my-list (list 1 2 3)) |
| 3045 | (define iter |
| 3046 | (make-iterator my-list my-list |
| 3047 | (lambda (iter) |
| 3048 | (let ((l (iterator-progress iter))) |
| 3049 | (if (eq? l '()) |
| 3050 | (end-of-iteration) |
| 3051 | (begin |
| 3052 | (set-iterator-progress! iter (cdr l)) |
| 3053 | (car l))))))) |
| 3054 | @end smallexample |
| 3055 | |
| 3056 | Here is a slightly more realistic example, which computes a list of all the |
| 3057 | functions in @code{my-global-block}. |
| 3058 | |
| 3059 | @smallexample |
| 3060 | (use-modules (gdb iterator)) |
| 3061 | (define this-sal (find-pc-line (frame-pc (selected-frame)))) |
| 3062 | (define this-symtab (sal-symtab this-sal)) |
| 3063 | (define this-global-block (symtab-global-block this-symtab)) |
| 3064 | (define syms-iter (make-block-symbols-iterator this-global-block)) |
| 3065 | (define functions (iterator-filter symbol-function? syms-iter)) |
| 3066 | @end smallexample |
| 3067 | @end deffn |
| 3068 | |
| 3069 | @deffn {Scheme Procedure} iterator? object |
| 3070 | Return @code{#t} if @var{object} is a @code{<gdb:iterator>} object. |
| 3071 | Otherwise return @code{#f}. |
| 3072 | @end deffn |
| 3073 | |
| 3074 | @deffn {Scheme Procedure} iterator-object iterator |
| 3075 | Return the first argument that was passed to @code{make-iterator}. |
| 3076 | This is the object being iterated over. |
| 3077 | @end deffn |
| 3078 | |
| 3079 | @deffn {Scheme Procedure} iterator-progress iterator |
| 3080 | Return the object tracking iteration progress. |
| 3081 | @end deffn |
| 3082 | |
| 3083 | @deffn {Scheme Procedure} set-iterator-progress! iterator new-value |
| 3084 | Set the object tracking iteration progress. |
| 3085 | @end deffn |
| 3086 | |
| 3087 | @deffn {Scheme Procedure} iterator-next! iterator |
| 3088 | Invoke the procedure that was the third argument to @code{make-iterator}, |
| 3089 | passing it one argument, the @code{<gdb:iterator>} object. |
| 3090 | The result is either the next element in the iteration, or an end |
| 3091 | marker as implemented by the @code{next!} procedure. |
| 3092 | By convention the end marker is the result of @code{(end-of-iteration)}. |
| 3093 | @end deffn |
| 3094 | |
| 3095 | @deffn {Scheme Procedure} end-of-iteration |
| 3096 | Return the Scheme object that denotes end of iteration. |
| 3097 | @end deffn |
| 3098 | |
| 3099 | @deffn {Scheme Procedure} end-of-iteration? object |
| 3100 | Return @code{#t} if @var{object} is the end of iteration marker. |
| 3101 | Otherwise return @code{#f}. |
| 3102 | @end deffn |
| 3103 | |
| 3104 | These functions are provided by the @code{(gdb iterator)} module to |
| 3105 | assist in using iterators. |
| 3106 | |
| 3107 | @deffn {Scheme Procedure} make-list-iterator list |
| 3108 | Return a @code{<gdb:iterator>} object that will iterate over @var{list}. |
| 3109 | @end deffn |
| 3110 | |
| 3111 | @deffn {Scheme Procedure} iterator->list iterator |
| 3112 | Return the elements pointed to by @var{iterator} as a list. |
| 3113 | @end deffn |
| 3114 | |
| 3115 | @deffn {Scheme Procedure} iterator-map proc iterator |
| 3116 | Return the list of objects obtained by applying @var{proc} to the object |
| 3117 | pointed to by @var{iterator} and to each subsequent object. |
| 3118 | @end deffn |
| 3119 | |
| 3120 | @deffn {Scheme Procedure} iterator-for-each proc iterator |
| 3121 | Apply @var{proc} to each element pointed to by @var{iterator}. |
| 3122 | The result is unspecified. |
| 3123 | @end deffn |
| 3124 | |
| 3125 | @deffn {Scheme Procedure} iterator-filter pred iterator |
| 3126 | Return the list of elements pointed to by @var{iterator} that satisfy |
| 3127 | @var{pred}. |
| 3128 | @end deffn |
| 3129 | |
| 3130 | @deffn {Scheme Procedure} iterator-until pred iterator |
| 3131 | Run @var{iterator} until the result of @code{(pred element)} is true |
| 3132 | and return that as the result. Otherwise return @code{#f}. |
| 3133 | @end deffn |
| 3134 | |
| 3135 | @node Guile Auto-loading |
| 3136 | @subsection Guile Auto-loading |
| 3137 | @cindex guile auto-loading |
| 3138 | |
| 3139 | When a new object file is read (for example, due to the @code{file} |
| 3140 | command, or because the inferior has loaded a shared library), |
| 3141 | @value{GDBN} will look for Guile support scripts in two ways: |
| 3142 | @file{@var{objfile}-gdb.scm} and the @code{.debug_gdb_scripts} section. |
| 3143 | @xref{Auto-loading extensions}. |
| 3144 | |
| 3145 | The auto-loading feature is useful for supplying application-specific |
| 3146 | debugging commands and scripts. |
| 3147 | |
| 3148 | Auto-loading can be enabled or disabled, |
| 3149 | and the list of auto-loaded scripts can be printed. |
| 3150 | |
| 3151 | @table @code |
| 3152 | @anchor{set auto-load guile-scripts} |
| 3153 | @kindex set auto-load guile-scripts |
| 3154 | @item set auto-load guile-scripts [on|off] |
| 3155 | Enable or disable the auto-loading of Guile scripts. |
| 3156 | |
| 3157 | @anchor{show auto-load guile-scripts} |
| 3158 | @kindex show auto-load guile-scripts |
| 3159 | @item show auto-load guile-scripts |
| 3160 | Show whether auto-loading of Guile scripts is enabled or disabled. |
| 3161 | |
| 3162 | @anchor{info auto-load guile-scripts} |
| 3163 | @kindex info auto-load guile-scripts |
| 3164 | @cindex print list of auto-loaded Guile scripts |
| 3165 | @item info auto-load guile-scripts [@var{regexp}] |
| 3166 | Print the list of all Guile scripts that @value{GDBN} auto-loaded. |
| 3167 | |
| 3168 | Also printed is the list of Guile scripts that were mentioned in |
| 3169 | the @code{.debug_gdb_scripts} section and were not found. |
| 3170 | This is useful because their names are not printed when @value{GDBN} |
| 3171 | tries to load them and fails. There may be many of them, and printing |
| 3172 | an error message for each one is problematic. |
| 3173 | |
| 3174 | If @var{regexp} is supplied only Guile scripts with matching names are printed. |
| 3175 | |
| 3176 | Example: |
| 3177 | |
| 3178 | @smallexample |
| 3179 | (gdb) info auto-load guile-scripts |
| 3180 | Loaded Script |
| 3181 | Yes scm-section-script.scm |
| 3182 | full name: /tmp/scm-section-script.scm |
| 3183 | No my-foo-pretty-printers.scm |
| 3184 | @end smallexample |
| 3185 | @end table |
| 3186 | |
| 3187 | When reading an auto-loaded file, @value{GDBN} sets the |
| 3188 | @dfn{current objfile}. This is available via the @code{current-objfile} |
| 3189 | procedure (@pxref{Objfiles In Guile}). This can be useful for |
| 3190 | registering objfile-specific pretty-printers. |
| 3191 | |
| 3192 | @node Guile Modules |
| 3193 | @subsection Guile Modules |
| 3194 | @cindex guile modules |
| 3195 | |
| 3196 | @value{GDBN} comes with several modules to assist writing Guile code. |
| 3197 | |
| 3198 | @menu |
| 3199 | * Guile Printing Module:: Building and registering pretty-printers |
| 3200 | * Guile Types Module:: Utilities for working with types |
| 3201 | @end menu |
| 3202 | |
| 3203 | @node Guile Printing Module |
| 3204 | @subsubsection Guile Printing Module |
| 3205 | |
| 3206 | This module provides a collection of utilities for working with |
| 3207 | pretty-printers. |
| 3208 | |
| 3209 | Usage: |
| 3210 | |
| 3211 | @smallexample |
| 3212 | (use-modules (gdb printing)) |
| 3213 | @end smallexample |
| 3214 | |
| 3215 | @deffn {Scheme Procedure} prepend-pretty-printer! object printer |
| 3216 | Add @var{printer} to the front of the list of pretty-printers for |
| 3217 | @var{object}. @var{object} must either be a @code{<gdb:objfile>} object |
| 3218 | or @code{#f} in which case @var{printer} is added to the global list of |
| 3219 | printers. |
| 3220 | @end deffn |
| 3221 | |
| 3222 | @deffn {Scheme Procecure} append-pretty-printer! object printer |
| 3223 | Add @var{printer} to the end of the list of pretty-printers for |
| 3224 | @var{object}. @var{object} must either be a @code{<gdb:objfile>} object |
| 3225 | or @code{#f} in which case @var{printer} is added to the global list of |
| 3226 | printers. |
| 3227 | @end deffn |
| 3228 | |
| 3229 | @node Guile Types Module |
| 3230 | @subsubsection Guile Types Module |
| 3231 | |
| 3232 | This module provides a collection of utilities for working with |
| 3233 | @code{<gdb:type>} objects. |
| 3234 | |
| 3235 | Usage: |
| 3236 | |
| 3237 | @smallexample |
| 3238 | (use-modules (gdb types)) |
| 3239 | @end smallexample |
| 3240 | |
| 3241 | @deffn {Scheme Procedure} get-basic-type type |
| 3242 | Return @var{type} with const and volatile qualifiers stripped, |
| 3243 | and with typedefs and C@t{++} references converted to the underlying type. |
| 3244 | |
| 3245 | C@t{++} example: |
| 3246 | |
| 3247 | @smallexample |
| 3248 | typedef const int const_int; |
| 3249 | const_int foo (3); |
| 3250 | const_int& foo_ref (foo); |
| 3251 | int main () @{ return 0; @} |
| 3252 | @end smallexample |
| 3253 | |
| 3254 | Then in gdb: |
| 3255 | |
| 3256 | @smallexample |
| 3257 | (gdb) start |
| 3258 | (gdb) guile (use-modules ((gdb) (gdb types))) |
| 3259 | (gdb) guile (define foo-ref (parse-and-eval "foo_ref")) |
| 3260 | (gdb) guile (get-basic-type (value-type foo-ref)) |
| 3261 | int |
| 3262 | @end smallexample |
| 3263 | @end deffn |
| 3264 | |
| 3265 | @deffn {Scheme Procedure} type-has-field-deep? type field |
| 3266 | Return @code{#t} if @var{type}, assumed to be a type with fields |
| 3267 | (e.g., a structure or union), has field @var{field}. |
| 3268 | Otherwise return @code{#f}. |
| 3269 | This searches baseclasses, whereas @code{type-has-field?} does not. |
| 3270 | @end deffn |
| 3271 | |
| 3272 | @deffn {Scheme Procedure} make-enum-hashtable enum-type |
| 3273 | Return a Guile hash table produced from @var{enum-type}. |
| 3274 | Elements in the hash table are referenced with @code{hashq-ref}. |
| 3275 | @end deffn |