1 What has changed in GDB?
2 (Organized release by release)
4 *** Changes since GDB 7.9
8 ** gdb.Objfile objects have a new attribute "username",
9 which is the name of the objfile as specified by the user,
10 without, for example, resolving symlinks.
14 * The command 'thread apply all' can now support new option '-ascending'
15 to call its specified command for all threads in ascending order.
17 *** Changes in GDB 7.9
19 * GDB now supports hardware watchpoints on x86 GNU Hurd.
23 ** You can now access frame registers from Python scripts.
24 ** New attribute 'producer' for gdb.Symtab objects.
25 ** gdb.Objfile objects have a new attribute "progspace",
26 which is the gdb.Progspace object of the containing program space.
27 ** gdb.Objfile objects have a new attribute "owner".
28 ** gdb.Objfile objects have a new attribute "build_id",
29 which is the build ID generated when the file was built.
30 ** gdb.Objfile objects have a new method "add_separate_debug_file".
31 ** A new event "gdb.clear_objfiles" has been added, triggered when
32 selecting a new file to debug.
33 ** You can now add attributes to gdb.Objfile and gdb.Progspace objects.
34 ** New function gdb.lookup_objfile.
36 New events which are triggered when GDB modifies the state of the
39 ** gdb.events.inferior_call_pre: Function call is about to be made.
40 ** gdb.events.inferior_call_post: Function call has just been made.
41 ** gdb.events.memory_changed: A memory location has been altered.
42 ** gdb.events.register_changed: A register has been altered.
44 * New Python-based convenience functions:
46 ** $_caller_is(name [, number_of_frames])
47 ** $_caller_matches(regexp [, number_of_frames])
48 ** $_any_caller_is(name [, number_of_frames])
49 ** $_any_caller_matches(regexp [, number_of_frames])
51 * GDB now supports the compilation and injection of source code into
52 the inferior. GDB will use GCC 5.0 or higher built with libcc1.so
53 to compile the source code to object code, and if successful, inject
54 and execute that code within the current context of the inferior.
55 Currently the C language is supported. The commands used to
56 interface with this new feature are:
58 compile code [-raw|-r] [--] [source code]
59 compile file [-raw|-r] filename
63 demangle [-l language] [--] name
64 Demangle "name" in the specified language, or the current language
65 if elided. This command is renamed from the "maint demangle" command.
66 The latter is kept as a no-op to avoid "maint demangle" being interpreted
67 as "maint demangler-warning".
69 queue-signal signal-name-or-number
70 Queue a signal to be delivered to the thread when it is resumed.
72 add-auto-load-scripts-directory directory
73 Add entries to the list of directories from which to load auto-loaded
76 maint print user-registers
77 List all currently available "user" registers.
79 compile code [-r|-raw] [--] [source code]
80 Compile, inject, and execute in the inferior the executable object
81 code produced by compiling the provided source code.
83 compile file [-r|-raw] filename
84 Compile and inject into the inferior the executable object code
85 produced by compiling the source code stored in the filename
88 * On resume, GDB now always passes the signal the program had stopped
89 for to the thread the signal was sent to, even if the user changed
90 threads before resuming. Previously GDB would often (but not
91 always) deliver the signal to the thread that happens to be current
94 * Conversely, the "signal" command now consistently delivers the
95 requested signal to the current thread. GDB now asks for
96 confirmation if the program had stopped for a signal and the user
97 switched threads meanwhile.
99 * "breakpoint always-inserted" modes "off" and "auto" merged.
101 Now, when 'breakpoint always-inserted mode' is set to "off", GDB
102 won't remove breakpoints from the target until all threads stop,
103 even in non-stop mode. The "auto" mode has been removed, and "off"
104 is now the default mode.
108 set debug symbol-lookup
109 show debug symbol-lookup
110 Control display of debugging info regarding symbol lookup.
114 ** The -list-thread-groups command outputs an exit-code field for
115 inferiors that have exited.
119 MIPS SDE mips*-sde*-elf*
123 Support for these obsolete configurations has been removed.
125 Alpha running OSF/1 (or Tru64) alpha*-*-osf*
126 SGI Irix-5.x mips-*-irix5*
127 SGI Irix-6.x mips-*-irix6*
128 VAX running (4.2 - 4.3 Reno) BSD vax-*-bsd*
129 VAX running Ultrix vax-*-ultrix*
131 * The "dll-symbols" command, and its two aliases ("add-shared-symbol-files"
132 and "assf"), have been removed. Use the "sharedlibrary" command, or
133 its alias "share", instead.
135 *** Changes in GDB 7.8
137 * New command line options
140 This is an alias for the --data-directory option.
142 * GDB supports printing and modifying of variable length automatic arrays
143 as specified in ISO C99.
145 * The ARM simulator now supports instruction level tracing
146 with or without disassembly.
150 GDB now has support for scripting using Guile. Whether this is
151 available is determined at configure time.
152 Guile version 2.0 or greater is required.
153 Guile version 2.0.9 is well tested, earlier 2.0 versions are not.
155 * New commands (for set/show, see "New options" below)
159 Invoke CODE by passing it to the Guile interpreter.
163 Start a Guile interactive prompt (or "repl" for "read-eval-print loop").
165 info auto-load guile-scripts [regexp]
166 Print the list of automatically loaded Guile scripts.
168 * The source command is now capable of sourcing Guile scripts.
169 This feature is dependent on the debugger being built with Guile support.
173 set print symbol-loading (off|brief|full)
174 show print symbol-loading
175 Control whether to print informational messages when loading symbol
176 information for a file. The default is "full", but when debugging
177 programs with large numbers of shared libraries the amount of output
180 set guile print-stack (none|message|full)
181 show guile print-stack
182 Show a stack trace when an error is encountered in a Guile script.
184 set auto-load guile-scripts (on|off)
185 show auto-load guile-scripts
186 Control auto-loading of Guile script files.
188 maint ada set ignore-descriptive-types (on|off)
189 maint ada show ignore-descriptive-types
190 Control whether the debugger should ignore descriptive types in Ada
191 programs. The default is not to ignore the descriptive types. See
192 the user manual for more details on descriptive types and the intended
193 usage of this option.
195 set auto-connect-native-target
197 Control whether GDB is allowed to automatically connect to the
198 native target for the run, attach, etc. commands when not connected
199 to any target yet. See also "target native" below.
201 set record btrace replay-memory-access (read-only|read-write)
202 show record btrace replay-memory-access
203 Control what memory accesses are allowed during replay.
205 maint set target-async (on|off)
206 maint show target-async
207 This controls whether GDB targets operate in synchronous or
208 asynchronous mode. Normally the default is asynchronous, if it is
209 available; but this can be changed to more easily debug problems
210 occurring only in synchronous mode.
212 set mi-async (on|off)
214 Control whether MI asynchronous mode is preferred. This supersedes
215 "set target-async" of previous GDB versions.
217 * "set target-async" is deprecated as a CLI option and is now an alias
218 for "set mi-async" (only puts MI into async mode).
220 * Background execution commands (e.g., "c&", "s&", etc.) are now
221 possible ``out of the box'' if the target supports them. Previously
222 the user would need to explicitly enable the possibility with the
223 "set target-async on" command.
225 * New features in the GDB remote stub, GDBserver
227 ** New option --debug-format=option1[,option2,...] allows one to add
228 additional text to each output. At present only timestamps
229 are supported: --debug-format=timestamps.
230 Timestamps can also be turned on with the
231 "monitor set debug-format timestamps" command from GDB.
233 * The 'record instruction-history' command now starts counting instructions
234 at one. This also affects the instruction ranges reported by the
235 'record function-call-history' command when given the /i modifier.
237 * The command 'record function-call-history' supports a new modifier '/c' to
238 indent the function names based on their call stack depth.
239 The fields for the '/i' and '/l' modifier have been reordered.
240 The source line range is now prefixed with 'at'.
241 The instruction range is now prefixed with 'inst'.
242 Both ranges are now printed as '<from>, <to>' to allow copy&paste to the
243 "record instruction-history" and "list" commands.
245 * The ranges given as arguments to the 'record function-call-history' and
246 'record instruction-history' commands are now inclusive.
248 * The btrace record target now supports the 'record goto' command.
249 For locations inside the execution trace, the back trace is computed
250 based on the information stored in the execution trace.
252 * The btrace record target supports limited reverse execution and replay.
253 The target does not record data and therefore does not allow reading
256 * The "catch syscall" command now works on s390*-linux* targets.
258 * The "compare-sections" command is no longer specific to target
259 remote. It now works with all targets.
261 * All native targets are now consistently called "native".
262 Consequently, the "target child", "target GNU", "target djgpp",
263 "target procfs" (Solaris/Irix/OSF/AIX) and "target darwin-child"
264 commands have been replaced with "target native". The QNX/NTO port
265 leaves the "procfs" target in place and adds a "native" target for
266 consistency with other ports. The impact on users should be minimal
267 as these commands previously either throwed an error, or were
268 no-ops. The target's name is visible in the output of the following
269 commands: "help target", "info target", "info files", "maint print
272 * The "target native" command now connects to the native target. This
273 can be used to launch native programs even when "set
274 auto-connect-native-target" is set to off.
276 * GDB now supports access to Intel(R) MPX registers on GNU/Linux.
278 * Support for Intel(R) AVX-512 registers on GNU/Linux.
279 Support displaying and modifying Intel(R) AVX-512 registers
280 $zmm0 - $zmm31 and $k0 - $k7 on GNU/Linux.
284 qXfer:btrace:read's annex
285 The qXfer:btrace:read packet supports a new annex 'delta' to read
286 branch trace incrementally.
290 ** Valid Python operations on gdb.Value objects representing
291 structs/classes invoke the corresponding overloaded operators if
293 ** New `Xmethods' feature in the Python API. Xmethods are
294 additional methods or replacements for existing methods of a C++
295 class. This feature is useful for those cases where a method
296 defined in C++ source code could be inlined or optimized out by
297 the compiler, making it unavailable to GDB.
300 PowerPC64 GNU/Linux little-endian powerpc64le-*-linux*
302 * The "dll-symbols" command, and its two aliases ("add-shared-symbol-files"
303 and "assf"), have been deprecated. Use the "sharedlibrary" command, or
304 its alias "share", instead.
306 * The commands "set remotebaud" and "show remotebaud" are no longer
307 supported. Use "set serial baud" and "show serial baud" (respectively)
312 ** A new option "-gdb-set mi-async" replaces "-gdb-set
313 target-async". The latter is left as a deprecated alias of the
314 former for backward compatibility. If the target supports it,
315 CLI background execution commands are now always possible by
316 default, independently of whether the frontend stated a
317 preference for asynchronous execution with "-gdb-set mi-async".
318 Previously "-gdb-set target-async off" affected both MI execution
319 commands and CLI execution commands.
321 *** Changes in GDB 7.7
323 * Improved support for process record-replay and reverse debugging on
324 arm*-linux* targets. Support for thumb32 and syscall instruction
325 recording has been added.
327 * GDB now supports SystemTap SDT probes on AArch64 GNU/Linux.
329 * GDB now supports Fission DWP file format version 2.
330 http://gcc.gnu.org/wiki/DebugFission
332 * New convenience function "$_isvoid", to check whether an expression
333 is void. A void expression is an expression where the type of the
334 result is "void". For example, some convenience variables may be
335 "void" when evaluated (e.g., "$_exitcode" before the execution of
336 the program being debugged; or an undefined convenience variable).
337 Another example, when calling a function whose return type is
340 * The "maintenance print objfiles" command now takes an optional regexp.
342 * The "catch syscall" command now works on arm*-linux* targets.
344 * GDB now consistently shows "<not saved>" when printing values of
345 registers the debug info indicates have not been saved in the frame
346 and there's nowhere to retrieve them from
347 (callee-saved/call-clobbered registers):
352 (gdb) info registers rax
355 Before, the former would print "<optimized out>", and the latter
356 "*value not available*".
358 * New script contrib/gdb-add-index.sh for adding .gdb_index sections
363 ** Frame filters and frame decorators have been added.
364 ** Temporary breakpoints are now supported.
365 ** Line tables representation has been added.
366 ** New attribute 'parent_type' for gdb.Field objects.
367 ** gdb.Field objects can be used as subscripts on gdb.Value objects.
368 ** New attribute 'name' for gdb.Type objects.
372 Nios II ELF nios2*-*-elf
373 Nios II GNU/Linux nios2*-*-linux
374 Texas Instruments MSP430 msp430*-*-elf
376 * Removed native configurations
378 Support for these a.out NetBSD and OpenBSD obsolete configurations has
379 been removed. ELF variants of these configurations are kept supported.
381 arm*-*-netbsd* but arm*-*-netbsdelf* is kept supported.
382 i[34567]86-*-netbsd* but i[34567]86-*-netbsdelf* is kept supported.
383 i[34567]86-*-openbsd[0-2].* but i[34567]86-*-openbsd* is kept supported.
384 i[34567]86-*-openbsd3.[0-3]
385 m68*-*-netbsd* but m68*-*-netbsdelf* is kept supported.
386 sparc-*-netbsd* but sparc-*-netbsdelf* is kept supported.
387 vax-*-netbsd* but vax-*-netbsdelf* is kept supported.
391 Like "catch throw", but catches a re-thrown exception.
393 Renamed from old "maint check-symtabs".
395 Perform consistency checks on symtabs.
397 Expand symtabs matching an optional regexp.
400 Display the details of GDB configure-time options.
402 maint set|show per-command
403 maint set|show per-command space
404 maint set|show per-command time
405 maint set|show per-command symtab
406 Enable display of per-command gdb resource usage.
408 remove-symbol-file FILENAME
409 remove-symbol-file -a ADDRESS
410 Remove a symbol file added via add-symbol-file. The file to remove
411 can be identified by its filename or by an address that lies within
412 the boundaries of this symbol file in memory.
415 info exceptions REGEXP
416 Display the list of Ada exceptions defined in the program being
417 debugged. If provided, only the exceptions whose names match REGEXP
422 set debug symfile off|on
424 Control display of debugging info regarding reading symbol files and
425 symbol tables within those files
427 set print raw frame-arguments
428 show print raw frame-arguments
429 Set/show whether to print frame arguments in raw mode,
430 disregarding any defined pretty-printers.
432 set remote trace-status-packet
433 show remote trace-status-packet
434 Set/show the use of remote protocol qTStatus packet.
438 Control display of debugging messages related to Nios II targets.
442 Control whether target-assisted range stepping is enabled.
444 set startup-with-shell
445 show startup-with-shell
446 Specifies whether Unix child processes are started via a shell or
451 Use the target memory cache for accesses to the code segment. This
452 improves performance of remote debugging (particularly disassembly).
454 * You can now use a literal value 'unlimited' for options that
455 interpret 0 or -1 as meaning "unlimited". E.g., "set
456 trace-buffer-size unlimited" is now an alias for "set
457 trace-buffer-size -1" and "set height unlimited" is now an alias for
460 * The "set debug symtab-create" debugging option of GDB has been changed to
461 accept a verbosity level. 0 means "off", 1 provides basic debugging
462 output, and values of 2 or greater provides more verbose output.
464 * New command-line options
466 Display the details of GDB configure-time options.
468 * The command 'tsave' can now support new option '-ctf' to save trace
469 buffer in Common Trace Format.
471 * Newly installed $prefix/bin/gcore acts as a shell interface for the
474 * GDB now implements the the C++ 'typeid' operator.
476 * The new convenience variable $_exception holds the exception being
477 thrown or caught at an exception-related catchpoint.
479 * The exception-related catchpoints, like "catch throw", now accept a
480 regular expression which can be used to filter exceptions by type.
482 * The new convenience variable $_exitsignal is automatically set to
483 the terminating signal number when the program being debugged dies
484 due to an uncaught signal.
488 ** All MI commands now accept an optional "--language" option.
489 Support for this feature can be verified by using the "-list-features"
490 command, which should contain "language-option".
492 ** The new command -info-gdb-mi-command allows the user to determine
493 whether a GDB/MI command is supported or not.
495 ** The "^error" result record returned when trying to execute an undefined
496 GDB/MI command now provides a variable named "code" whose content is the
497 "undefined-command" error code. Support for this feature can be verified
498 by using the "-list-features" command, which should contain
499 "undefined-command-error-code".
501 ** The -trace-save MI command can optionally save trace buffer in Common
504 ** The new command -dprintf-insert sets a dynamic printf breakpoint.
506 ** The command -data-list-register-values now accepts an optional
507 "--skip-unavailable" option. When used, only the available registers
510 ** The new command -trace-frame-collected dumps collected variables,
511 computed expressions, tvars, memory and registers in a traceframe.
513 ** The commands -stack-list-locals, -stack-list-arguments and
514 -stack-list-variables now accept an option "--skip-unavailable".
515 When used, only the available locals or arguments are displayed.
517 ** The -exec-run command now accepts an optional "--start" option.
518 When used, the command follows the same semantics as the "start"
519 command, stopping the program's execution at the start of its
520 main subprogram. Support for this feature can be verified using
521 the "-list-features" command, which should contain
522 "exec-run-start-option".
524 ** The new commands -catch-assert and -catch-exceptions insert
525 catchpoints stopping the program when Ada exceptions are raised.
527 ** The new command -info-ada-exceptions provides the equivalent of
528 the new "info exceptions" command.
530 * New system-wide configuration scripts
531 A GDB installation now provides scripts suitable for use as system-wide
532 configuration scripts for the following systems:
536 * GDB now supports target-assigned range stepping with remote targets.
537 This improves the performance of stepping source lines by reducing
538 the number of control packets from/to GDB. See "New remote packets"
541 * GDB now understands the element 'tvar' in the XML traceframe info.
542 It has the id of the collected trace state variables.
544 * On S/390 targets that provide the transactional-execution feature,
545 the program interruption transaction diagnostic block (TDB) is now
546 represented as a number of additional "registers" in GDB.
552 The vCont packet supports a new 'r' action, that tells the remote
553 stub to step through an address range itself, without GDB
554 involvemement at each single-step.
556 qXfer:libraries-svr4:read's annex
557 The previously unused annex of the qXfer:libraries-svr4:read packet
558 is now used to support passing an argument list. The remote stub
559 reports support for this argument list to GDB's qSupported query.
560 The defined arguments are "start" and "prev", used to reduce work
561 necessary for library list updating, resulting in significant
564 * New features in the GDB remote stub, GDBserver
566 ** GDBserver now supports target-assisted range stepping. Currently
567 enabled on x86/x86_64 GNU/Linux targets.
569 ** GDBserver now adds element 'tvar' in the XML in the reply to
570 'qXfer:traceframe-info:read'. It has the id of the collected
571 trace state variables.
573 ** GDBserver now supports hardware watchpoints on the MIPS GNU/Linux
576 * New 'z' formatter for printing and examining memory, this displays the
577 value as hexadecimal zero padded on the left to the size of the type.
579 * GDB can now use Windows x64 unwinding data.
581 * The "set remotebaud" command has been replaced by "set serial baud".
582 Similarly, "show remotebaud" has been replaced by "show serial baud".
583 The "set remotebaud" and "show remotebaud" commands are still available
584 to provide backward compatibility with older versions of GDB.
586 *** Changes in GDB 7.6
588 * Target record has been renamed to record-full.
589 Record/replay is now enabled with the "record full" command.
590 This also affects settings that are associated with full record/replay
591 that have been moved from "set/show record" to "set/show record full":
593 set|show record full insn-number-max
594 set|show record full stop-at-limit
595 set|show record full memory-query
597 * A new record target "record-btrace" has been added. The new target
598 uses hardware support to record the control-flow of a process. It
599 does not support replaying the execution, but it implements the
600 below new commands for investigating the recorded execution log.
601 This new recording method can be enabled using:
605 The "record-btrace" target is only available on Intel Atom processors
606 and requires a Linux kernel 2.6.32 or later.
608 * Two new commands have been added for record/replay to give information
609 about the recorded execution without having to replay the execution.
610 The commands are only supported by "record btrace".
612 record instruction-history prints the execution history at
613 instruction granularity
615 record function-call-history prints the execution history at
618 * New native configurations
620 ARM AArch64 GNU/Linux aarch64*-*-linux-gnu
621 FreeBSD/powerpc powerpc*-*-freebsd
622 x86_64/Cygwin x86_64-*-cygwin*
623 Tilera TILE-Gx GNU/Linux tilegx*-*-linux-gnu
627 ARM AArch64 aarch64*-*-elf
628 ARM AArch64 GNU/Linux aarch64*-*-linux
629 Lynx 178 PowerPC powerpc-*-lynx*178
630 x86_64/Cygwin x86_64-*-cygwin*
631 Tilera TILE-Gx GNU/Linux tilegx*-*-linux
633 * If the configured location of system.gdbinit file (as given by the
634 --with-system-gdbinit option at configure time) is in the
635 data-directory (as specified by --with-gdb-datadir at configure
636 time) or in one of its subdirectories, then GDB will look for the
637 system-wide init file in the directory specified by the
638 --data-directory command-line option.
640 * New command line options:
642 -nh Disables auto-loading of ~/.gdbinit, but still executes all the
643 other initialization files, unlike -nx which disables all of them.
645 * Removed command line options
647 -epoch This was used by the gdb mode in Epoch, an ancient fork of
650 * The 'ptype' and 'whatis' commands now accept an argument to control
653 * 'info proc' now works on some core files.
657 ** Vectors can be created with gdb.Type.vector.
659 ** Python's atexit.register now works in GDB.
661 ** Types can be pretty-printed via a Python API.
663 ** Python 3 is now supported (in addition to Python 2.4 or later)
665 ** New class gdb.Architecture exposes GDB's internal representation
666 of architecture in the Python API.
668 ** New method Frame.architecture returns the gdb.Architecture object
669 corresponding to the frame's architecture.
671 * New Python-based convenience functions:
673 ** $_memeq(buf1, buf2, length)
674 ** $_streq(str1, str2)
676 ** $_regex(str, regex)
678 * The 'cd' command now defaults to using '~' (the home directory) if not
681 * The C++ ABI now defaults to the GNU v3 ABI. This has been the
682 default for GCC since November 2000.
684 * The command 'forward-search' can now be abbreviated as 'fo'.
686 * The command 'info tracepoints' can now display 'installed on target'
687 or 'not installed on target' for each non-pending location of tracepoint.
689 * New configure options
691 --enable-libmcheck/--disable-libmcheck
692 By default, development versions are built with -lmcheck on hosts
693 that support it, in order to help track memory corruption issues.
694 Release versions, on the other hand, are built without -lmcheck
695 by default. The --enable-libmcheck/--disable-libmcheck configure
696 options allow the user to override that default.
697 --with-babeltrace/--with-babeltrace-include/--with-babeltrace-lib
698 This configure option allows the user to build GDB with
699 libbabeltrace using which GDB can read Common Trace Format data.
701 * New commands (for set/show, see "New options" below)
704 Catch signals. This is similar to "handle", but allows commands and
705 conditions to be attached.
708 List the BFDs known to GDB.
710 python-interactive [command]
712 Start a Python interactive prompt, or evaluate the optional command
713 and print the result of expressions.
716 "py" is a new alias for "python".
718 enable type-printer [name]...
719 disable type-printer [name]...
720 Enable or disable type printers.
724 ** For the Renesas Super-H architecture, the "regs" command has been removed
725 (has been deprecated in GDB 7.5), and "info all-registers" should be used
730 set print type methods (on|off)
731 show print type methods
732 Control whether method declarations are displayed by "ptype".
733 The default is to show them.
735 set print type typedefs (on|off)
736 show print type typedefs
737 Control whether typedef definitions are displayed by "ptype".
738 The default is to show them.
740 set filename-display basename|relative|absolute
741 show filename-display
742 Control the way in which filenames is displayed.
743 The default is "relative", which preserves previous behavior.
745 set trace-buffer-size
746 show trace-buffer-size
747 Request target to change the size of trace buffer.
749 set remote trace-buffer-size-packet auto|on|off
750 show remote trace-buffer-size-packet
751 Control the use of the remote protocol `QTBuffer:size' packet.
755 Control display of debugging messages related to ARM AArch64.
758 set debug coff-pe-read
759 show debug coff-pe-read
760 Control display of debugging messages related to reading of COFF/PE
765 Control display of debugging messages related to Mach-O symbols
768 set debug notification
769 show debug notification
770 Control display of debugging info for async remote notification.
774 ** Command parameter changes are now notified using new async record
775 "=cmd-param-changed".
776 ** Trace frame changes caused by command "tfind" are now notified using
777 new async record "=traceframe-changed".
778 ** The creation, deletion and modification of trace state variables
779 are now notified using new async records "=tsv-created",
780 "=tsv-deleted" and "=tsv-modified".
781 ** The start and stop of process record are now notified using new
782 async record "=record-started" and "=record-stopped".
783 ** Memory changes are now notified using new async record
785 ** The data-disassemble command response will include a "fullname" field
786 containing the absolute file name when source has been requested.
787 ** New optional parameter COUNT added to the "-data-write-memory-bytes"
788 command, to allow pattern filling of memory areas.
789 ** New commands "-catch-load"/"-catch-unload" added for intercepting
790 library load/unload events.
791 ** The response to breakpoint commands and breakpoint async records
792 includes an "installed" field containing a boolean state about each
793 non-pending tracepoint location is whether installed on target or not.
794 ** Output of the "-trace-status" command includes a "trace-file" field
795 containing the name of the trace file being examined. This field is
796 optional, and only present when examining a trace file.
797 ** The "fullname" field is now always present along with the "file" field,
798 even if the file cannot be found by GDB.
800 * GDB now supports the "mini debuginfo" section, .gnu_debugdata.
801 You must have the LZMA library available when configuring GDB for this
802 feature to be enabled. For more information, see:
803 http://fedoraproject.org/wiki/Features/MiniDebugInfo
808 Set the size of trace buffer. The remote stub reports support for this
809 packet to gdb's qSupported query.
812 Enable Branch Trace Store (BTS)-based branch tracing for the current
813 thread. The remote stub reports support for this packet to gdb's
817 Disable branch tracing for the current thread. The remote stub reports
818 support for this packet to gdb's qSupported query.
821 Read the traced branches for the current thread. The remote stub
822 reports support for this packet to gdb's qSupported query.
824 *** Changes in GDB 7.5
826 * GDB now supports x32 ABI. Visit <http://sites.google.com/site/x32abi/>
827 for more x32 ABI info.
829 * GDB now supports access to MIPS DSP registers on Linux targets.
831 * GDB now supports debugging microMIPS binaries.
833 * The "info os" command on GNU/Linux can now display information on
834 several new classes of objects managed by the operating system:
835 "info os procgroups" lists process groups
836 "info os files" lists file descriptors
837 "info os sockets" lists internet-domain sockets
838 "info os shm" lists shared-memory regions
839 "info os semaphores" lists semaphores
840 "info os msg" lists message queues
841 "info os modules" lists loaded kernel modules
843 * GDB now has support for SDT (Static Defined Tracing) probes. Currently,
844 the only implemented backend is for SystemTap probes (<sys/sdt.h>). You
845 can set a breakpoint using the new "-probe, "-pstap" or "-probe-stap"
846 options and inspect the probe arguments using the new $_probe_arg family
847 of convenience variables. You can obtain more information about SystemTap
848 in <http://sourceware.org/systemtap/>.
850 * GDB now supports reversible debugging on ARM, it allows you to
851 debug basic ARM and THUMB instructions, and provides
852 record/replay support.
854 * The option "symbol-reloading" has been deleted as it is no longer used.
858 ** GDB commands implemented in Python can now be put in command class
861 ** The "maint set python print-stack on|off" is now deleted.
863 ** A new class, gdb.printing.FlagEnumerationPrinter, can be used to
864 apply "flag enum"-style pretty-printing to any enum.
866 ** gdb.lookup_symbol can now work when there is no current frame.
868 ** gdb.Symbol now has a 'line' attribute, holding the line number in
869 the source at which the symbol was defined.
871 ** gdb.Symbol now has the new attribute 'needs_frame' and the new
872 method 'value'. The former indicates whether the symbol needs a
873 frame in order to compute its value, and the latter computes the
876 ** A new method 'referenced_value' on gdb.Value objects which can
877 dereference pointer as well as C++ reference values.
879 ** New methods 'global_block' and 'static_block' on gdb.Symtab objects
880 which return the global and static blocks (as gdb.Block objects),
881 of the underlying symbol table, respectively.
883 ** New function gdb.find_pc_line which returns the gdb.Symtab_and_line
884 object associated with a PC value.
886 ** gdb.Symtab_and_line has new attribute 'last' which holds the end
887 of the address range occupied by code for the current source line.
889 * Go language support.
890 GDB now supports debugging programs written in the Go programming
893 * GDBserver now supports stdio connections.
894 E.g. (gdb) target remote | ssh myhost gdbserver - hello
896 * The binary "gdbtui" can no longer be built or installed.
897 Use "gdb -tui" instead.
899 * GDB will now print "flag" enums specially. A flag enum is one where
900 all the enumerator values have no bits in common when pairwise
901 "and"ed. When printing a value whose type is a flag enum, GDB will
902 show all the constants, e.g., for enum E { ONE = 1, TWO = 2}:
903 (gdb) print (enum E) 3
906 * The filename part of a linespec will now match trailing components
907 of a source file name. For example, "break gcc/expr.c:1000" will
908 now set a breakpoint in build/gcc/expr.c, but not
911 * The "info proc" and "generate-core-file" commands will now also
912 work on remote targets connected to GDBserver on Linux.
914 * The command "info catch" has been removed. It has been disabled
917 * The "catch exception" and "catch assert" commands now accept
918 a condition at the end of the command, much like the "break"
919 command does. For instance:
921 (gdb) catch exception Constraint_Error if Barrier = True
923 Previously, it was possible to add a condition to such catchpoints,
924 but it had to be done as a second step, after the catchpoint had been
925 created, using the "condition" command.
927 * The "info static-tracepoint-marker" command will now also work on
928 native Linux targets with in-process agent.
930 * GDB can now set breakpoints on inlined functions.
932 * The .gdb_index section has been updated to include symbols for
933 inlined functions. GDB will ignore older .gdb_index sections by
934 default, which could cause symbol files to be loaded more slowly
935 until their .gdb_index sections can be recreated. The new command
936 "set use-deprecated-index-sections on" will cause GDB to use any older
937 .gdb_index sections it finds. This will restore performance, but the
938 ability to set breakpoints on inlined functions will be lost in symbol
939 files with older .gdb_index sections.
941 The .gdb_index section has also been updated to record more information
942 about each symbol. This speeds up the "info variables", "info functions"
943 and "info types" commands when used with programs having the .gdb_index
944 section, as well as speeding up debugging with shared libraries using
945 the .gdb_index section.
947 * Ada support for GDB/MI Variable Objects has been added.
949 * GDB can now support 'breakpoint always-inserted mode' in 'record'
954 ** New command -info-os is the MI equivalent of "info os".
956 ** Output logs ("set logging" and related) now include MI output.
960 ** "set use-deprecated-index-sections on|off"
961 "show use-deprecated-index-sections on|off"
962 Controls the use of deprecated .gdb_index sections.
964 ** "catch load" and "catch unload" can be used to stop when a shared
965 library is loaded or unloaded, respectively.
967 ** "enable count" can be used to auto-disable a breakpoint after
970 ** "info vtbl" can be used to show the virtual method tables for
971 C++ and Java objects.
973 ** "explore" and its sub commands "explore value" and "explore type"
974 can be used to recursively explore values and types of
975 expressions. These commands are available only if GDB is
976 configured with '--with-python'.
978 ** "info auto-load" shows status of all kinds of auto-loaded files,
979 "info auto-load gdb-scripts" shows status of auto-loading GDB canned
980 sequences of commands files, "info auto-load python-scripts"
981 shows status of auto-loading Python script files,
982 "info auto-load local-gdbinit" shows status of loading init file
983 (.gdbinit) from current directory and "info auto-load libthread-db" shows
984 status of inferior specific thread debugging shared library loading.
986 ** "info auto-load-scripts", "set auto-load-scripts on|off"
987 and "show auto-load-scripts" commands have been deprecated, use their
988 "info auto-load python-scripts", "set auto-load python-scripts on|off"
989 and "show auto-load python-scripts" counterparts instead.
991 ** "dprintf location,format,args..." creates a dynamic printf, which
992 is basically a breakpoint that does a printf and immediately
993 resumes your program's execution, so it is like a printf that you
994 can insert dynamically at runtime instead of at compiletime.
996 ** "set print symbol"
998 Controls whether GDB attempts to display the symbol, if any,
999 corresponding to addresses it prints. This defaults to "on", but
1000 you can set it to "off" to restore GDB's previous behavior.
1002 * Deprecated commands
1004 ** For the Renesas Super-H architecture, the "regs" command has been
1005 deprecated, and "info all-registers" should be used instead.
1009 Renesas RL78 rl78-*-elf
1010 HP OpenVMS ia64 ia64-hp-openvms*
1012 * GDBserver supports evaluation of breakpoint conditions. When
1013 support is advertised by GDBserver, GDB may be told to send the
1014 breakpoint conditions in bytecode form to GDBserver. GDBserver
1015 will only report the breakpoint trigger to GDB when its condition
1020 set mips compression
1021 show mips compression
1022 Select the compressed ISA encoding used in functions that have no symbol
1023 information available. The encoding can be set to either of:
1026 and is updated automatically from ELF file flags if available.
1028 set breakpoint condition-evaluation
1029 show breakpoint condition-evaluation
1030 Control whether breakpoint conditions are evaluated by GDB ("host") or by
1031 GDBserver ("target"). Default option "auto" chooses the most efficient
1033 This option can improve debugger efficiency depending on the speed of the
1037 Disable auto-loading globally.
1040 Show auto-loading setting of all kinds of auto-loaded files.
1042 set auto-load gdb-scripts on|off
1043 show auto-load gdb-scripts
1044 Control auto-loading of GDB canned sequences of commands files.
1046 set auto-load python-scripts on|off
1047 show auto-load python-scripts
1048 Control auto-loading of Python script files.
1050 set auto-load local-gdbinit on|off
1051 show auto-load local-gdbinit
1052 Control loading of init file (.gdbinit) from current directory.
1054 set auto-load libthread-db on|off
1055 show auto-load libthread-db
1056 Control auto-loading of inferior specific thread debugging shared library.
1058 set auto-load scripts-directory <dir1>[:<dir2>...]
1059 show auto-load scripts-directory
1060 Set a list of directories from which to load auto-loaded scripts.
1061 Automatically loaded Python scripts and GDB scripts are located in one
1062 of the directories listed by this option.
1063 The delimiter (':' above) may differ according to the host platform.
1065 set auto-load safe-path <dir1>[:<dir2>...]
1066 show auto-load safe-path
1067 Set a list of directories from which it is safe to auto-load files.
1068 The delimiter (':' above) may differ according to the host platform.
1070 set debug auto-load on|off
1071 show debug auto-load
1072 Control display of debugging info for auto-loading the files above.
1074 set dprintf-style gdb|call|agent
1076 Control the way in which a dynamic printf is performed; "gdb"
1077 requests a GDB printf command, while "call" causes dprintf to call a
1078 function in the inferior. "agent" requests that the target agent
1079 (such as GDBserver) do the printing.
1081 set dprintf-function <expr>
1082 show dprintf-function
1083 set dprintf-channel <expr>
1084 show dprintf-channel
1085 Set the function and optional first argument to the call when using
1086 the "call" style of dynamic printf.
1088 set disconnected-dprintf on|off
1089 show disconnected-dprintf
1090 Control whether agent-style dynamic printfs continue to be in effect
1091 after GDB disconnects.
1093 * New configure options
1095 --with-auto-load-dir
1096 Configure default value for the 'set auto-load scripts-directory'
1097 setting above. It defaults to '$debugdir:$datadir/auto-load',
1098 $debugdir representing global debugging info directories (available
1099 via 'show debug-file-directory') and $datadir representing GDB's data
1100 directory (available via 'show data-directory').
1102 --with-auto-load-safe-path
1103 Configure default value for the 'set auto-load safe-path' setting
1104 above. It defaults to the --with-auto-load-dir setting.
1106 --without-auto-load-safe-path
1107 Set 'set auto-load safe-path' to '/', effectively disabling this
1110 * New remote packets
1112 z0/z1 conditional breakpoints extension
1114 The z0/z1 breakpoint insertion packets have been extended to carry
1115 a list of conditional expressions over to the remote stub depending on the
1116 condition evaluation mode. The use of this extension can be controlled
1117 via the "set remote conditional-breakpoints-packet" command.
1121 Specify the signals which the remote stub may pass to the debugged
1122 program without GDB involvement.
1124 * New command line options
1126 --init-command=FILE, -ix Like --command, -x but execute it
1127 before loading inferior.
1128 --init-eval-command=COMMAND, -iex Like --eval-command=COMMAND, -ex but
1129 execute it before loading inferior.
1131 *** Changes in GDB 7.4
1133 * GDB now handles ambiguous linespecs more consistently; the existing
1134 FILE:LINE support has been expanded to other types of linespecs. A
1135 breakpoint will now be set on all matching locations in all
1136 inferiors, and locations will be added or removed according to
1139 * GDB now allows you to skip uninteresting functions and files when
1140 stepping with the "skip function" and "skip file" commands.
1142 * GDB has two new commands: "set remote hardware-watchpoint-length-limit"
1143 and "show remote hardware-watchpoint-length-limit". These allows to
1144 set or show the maximum length limit (in bytes) of a remote
1145 target hardware watchpoint.
1147 This allows e.g. to use "unlimited" hardware watchpoints with the
1148 gdbserver integrated in Valgrind version >= 3.7.0. Such Valgrind
1149 watchpoints are slower than real hardware watchpoints but are
1150 significantly faster than gdb software watchpoints.
1154 ** The register_pretty_printer function in module gdb.printing now takes
1155 an optional `replace' argument. If True, the new printer replaces any
1158 ** The "maint set python print-stack on|off" command has been
1159 deprecated and will be deleted in GDB 7.5.
1160 A new command: "set python print-stack none|full|message" has
1161 replaced it. Additionally, the default for "print-stack" is
1162 now "message", which just prints the error message without
1165 ** A prompt substitution hook (prompt_hook) is now available to the
1168 ** A new Python module, gdb.prompt has been added to the GDB Python
1169 modules library. This module provides functionality for
1170 escape sequences in prompts (used by set/show
1171 extended-prompt). These escape sequences are replaced by their
1172 corresponding value.
1174 ** Python commands and convenience-functions located in
1175 'data-directory'/python/gdb/command and
1176 'data-directory'/python/gdb/function are now automatically loaded
1179 ** Blocks now provide four new attributes. global_block and
1180 static_block will return the global and static blocks
1181 respectively. is_static and is_global are boolean attributes
1182 that indicate if the block is one of those two types.
1184 ** Symbols now provide the "type" attribute, the type of the symbol.
1186 ** The "gdb.breakpoint" function has been deprecated in favor of
1189 ** A new class "gdb.FinishBreakpoint" is provided to catch the return
1190 of a function. This class is based on the "finish" command
1191 available in the CLI.
1193 ** Type objects for struct and union types now allow access to
1194 the fields using standard Python dictionary (mapping) methods.
1195 For example, "some_type['myfield']" now works, as does
1196 "some_type.items()".
1198 ** A new event "gdb.new_objfile" has been added, triggered by loading a
1201 ** A new function, "deep_items" has been added to the gdb.types
1202 module in the GDB Python modules library. This function returns
1203 an iterator over the fields of a struct or union type. Unlike
1204 the standard Python "iteritems" method, it will recursively traverse
1205 any anonymous fields.
1209 ** "*stopped" events can report several new "reason"s, such as
1212 ** Breakpoint changes are now notified using new async records, like
1213 "=breakpoint-modified".
1215 ** New command -ada-task-info.
1217 * libthread-db-search-path now supports two special values: $sdir and $pdir.
1218 $sdir specifies the default system locations of shared libraries.
1219 $pdir specifies the directory where the libpthread used by the application
1222 GDB no longer looks in $sdir and $pdir after it has searched the directories
1223 mentioned in libthread-db-search-path. If you want to search those
1224 directories, they must be specified in libthread-db-search-path.
1225 The default value of libthread-db-search-path on GNU/Linux and Solaris
1226 systems is now "$sdir:$pdir".
1228 $pdir is not supported by gdbserver, it is currently ignored.
1229 $sdir is supported by gdbserver.
1231 * New configure option --with-iconv-bin.
1232 When using the internationalization support like the one in the GNU C
1233 library, GDB will invoke the "iconv" program to get a list of supported
1234 character sets. If this program lives in a non-standard location, one can
1235 use this option to specify where to find it.
1237 * When natively debugging programs on PowerPC BookE processors running
1238 a Linux kernel version 2.6.34 or later, GDB supports masked hardware
1239 watchpoints, which specify a mask in addition to an address to watch.
1240 The mask specifies that some bits of an address (the bits which are
1241 reset in the mask) should be ignored when matching the address accessed
1242 by the inferior against the watchpoint address. See the "PowerPC Embedded"
1243 section in the user manual for more details.
1245 * The new option --once causes GDBserver to stop listening for connections once
1246 the first connection is made. The listening port used by GDBserver will
1247 become available after that.
1249 * New commands "info macros" and "alias" have been added.
1251 * New function parameters suffix @entry specifies value of function parameter
1252 at the time the function got called. Entry values are available only since
1258 "!" is now an alias of the "shell" command.
1259 Note that no space is needed between "!" and SHELL COMMAND.
1263 watch EXPRESSION mask MASK_VALUE
1264 The watch command now supports the mask argument which allows creation
1265 of masked watchpoints, if the current architecture supports this feature.
1267 info auto-load-scripts [REGEXP]
1268 This command was formerly named "maintenance print section-scripts".
1269 It is now generally useful and is no longer a maintenance-only command.
1271 info macro [-all] [--] MACRO
1272 The info macro command has new options `-all' and `--'. The first for
1273 printing all definitions of a macro. The second for explicitly specifying
1274 the end of arguments and the beginning of the macro name in case the macro
1275 name starts with a hyphen.
1277 collect[/s] EXPRESSIONS
1278 The tracepoint collect command now takes an optional modifier "/s"
1279 that directs it to dereference pointer-to-character types and
1280 collect the bytes of memory up to a zero byte. The behavior is
1281 similar to what you see when you use the regular print command on a
1282 string. An optional integer following the "/s" sets a bound on the
1283 number of bytes that will be collected.
1286 The trace start command now interprets any supplied arguments as a
1287 note to be recorded with the trace run, with an effect similar to
1288 setting the variable trace-notes.
1291 The trace stop command now interprets any arguments as a note to be
1292 mentioned along with the tstatus report that the trace was stopped
1293 with a command. The effect is similar to setting the variable
1296 * Tracepoints can now be enabled and disabled at any time after a trace
1297 experiment has been started using the standard "enable" and "disable"
1298 commands. It is now possible to start a trace experiment with no enabled
1299 tracepoints; GDB will display a warning, but will allow the experiment to
1300 begin, assuming that tracepoints will be enabled as needed while the trace
1303 * Fast tracepoints on 32-bit x86-architectures can now be placed at
1304 locations with 4-byte instructions, when they were previously
1305 limited to locations with instructions of 5 bytes or longer.
1309 set debug dwarf2-read
1310 show debug dwarf2-read
1311 Turns on or off display of debugging messages related to reading
1312 DWARF debug info. The default is off.
1314 set debug symtab-create
1315 show debug symtab-create
1316 Turns on or off display of debugging messages related to symbol table
1317 creation. The default is off.
1320 show extended-prompt
1321 Set the GDB prompt, and allow escape sequences to be inserted to
1322 display miscellaneous information (see 'help set extended-prompt'
1323 for the list of sequences). This prompt (and any information
1324 accessed through the escape sequences) is updated every time the
1325 prompt is displayed.
1327 set print entry-values (both|compact|default|if-needed|no|only|preferred)
1328 show print entry-values
1329 Set printing of frame argument values at function entry. In some cases
1330 GDB can determine the value of function argument which was passed by the
1331 function caller, even if the value was modified inside the called function.
1333 set debug entry-values
1334 show debug entry-values
1335 Control display of debugging info for determining frame argument values at
1336 function entry and virtual tail call frames.
1338 set basenames-may-differ
1339 show basenames-may-differ
1340 Set whether a source file may have multiple base names.
1341 (A "base name" is the name of a file with the directory part removed.
1342 Example: The base name of "/home/user/hello.c" is "hello.c".)
1343 If set, GDB will canonicalize file names (e.g., expand symlinks)
1344 before comparing them. Canonicalization is an expensive operation,
1345 but it allows the same file be known by more than one base name.
1346 If not set (the default), all source files are assumed to have just
1347 one base name, and gdb will do file name comparisons more efficiently.
1353 Set a user name and notes for the current and any future trace runs.
1354 This is useful for long-running and/or disconnected traces, to
1355 inform others (or yourself) as to who is running the trace, supply
1356 contact information, or otherwise explain what is going on.
1358 set trace-stop-notes
1359 show trace-stop-notes
1360 Set a note attached to the trace run, that is displayed when the
1361 trace has been stopped by a tstop command. This is useful for
1362 instance as an explanation, if you are stopping a trace run that was
1363 started by someone else.
1365 * New remote packets
1369 Dynamically enable a tracepoint in a started trace experiment.
1373 Dynamically disable a tracepoint in a started trace experiment.
1377 Set the user and notes of the trace run.
1381 Query the current status of a tracepoint.
1385 Query the minimum length of instruction at which a fast tracepoint may
1388 * Dcache size (number of lines) and line-size are now runtime-configurable
1389 via "set dcache line" and "set dcache line-size" commands.
1393 Texas Instruments TMS320C6x tic6x-*-*
1397 Renesas RL78 rl78-*-elf
1399 *** Changes in GDB 7.3.1
1401 * The build failure for NetBSD and OpenBSD targets have now been fixed.
1403 *** Changes in GDB 7.3
1405 * GDB has a new command: "thread find [REGEXP]".
1406 It finds the thread id whose name, target id, or thread extra info
1407 matches the given regular expression.
1409 * The "catch syscall" command now works on mips*-linux* targets.
1411 * The -data-disassemble MI command now supports modes 2 and 3 for
1412 dumping the instruction opcodes.
1414 * New command line options
1416 -data-directory DIR Specify DIR as the "data-directory".
1417 This is mostly for testing purposes.
1419 * The "maint set python auto-load on|off" command has been renamed to
1420 "set auto-load-scripts on|off".
1422 * GDB has a new command: "set directories".
1423 It is like the "dir" command except that it replaces the
1424 source path list instead of augmenting it.
1426 * GDB now understands thread names.
1428 On GNU/Linux, "info threads" will display the thread name as set by
1429 prctl or pthread_setname_np.
1431 There is also a new command, "thread name", which can be used to
1432 assign a name internally for GDB to display.
1435 Initial support for the OpenCL C language (http://www.khronos.org/opencl)
1436 has been integrated into GDB.
1440 ** The function gdb.Write now accepts an optional keyword 'stream'.
1441 This keyword, when provided, will direct the output to either
1442 stdout, stderr, or GDB's logging output.
1444 ** Parameters can now be be sub-classed in Python, and in particular
1445 you may implement the get_set_doc and get_show_doc functions.
1446 This improves how Parameter set/show documentation is processed
1447 and allows for more dynamic content.
1449 ** Symbols, Symbol Table, Symbol Table and Line, Object Files,
1450 Inferior, Inferior Thread, Blocks, and Block Iterator APIs now
1451 have an is_valid method.
1453 ** Breakpoints can now be sub-classed in Python, and in particular
1454 you may implement a 'stop' function that is executed each time
1455 the inferior reaches that breakpoint.
1457 ** New function gdb.lookup_global_symbol looks up a global symbol.
1459 ** GDB values in Python are now callable if the value represents a
1460 function. For example, if 'some_value' represents a function that
1461 takes two integer parameters and returns a value, you can call
1462 that function like so:
1464 result = some_value (10,20)
1466 ** Module gdb.types has been added.
1467 It contains a collection of utilities for working with gdb.Types objects:
1468 get_basic_type, has_field, make_enum_dict.
1470 ** Module gdb.printing has been added.
1471 It contains utilities for writing and registering pretty-printers.
1472 New classes: PrettyPrinter, SubPrettyPrinter,
1473 RegexpCollectionPrettyPrinter.
1474 New function: register_pretty_printer.
1476 ** New commands "info pretty-printers", "enable pretty-printer" and
1477 "disable pretty-printer" have been added.
1479 ** gdb.parameter("directories") is now available.
1481 ** New function gdb.newest_frame returns the newest frame in the
1484 ** The gdb.InferiorThread class has a new "name" attribute. This
1485 holds the thread's name.
1487 ** Python Support for Inferior events.
1488 Python scripts can add observers to be notified of events
1489 occurring in the process being debugged.
1490 The following events are currently supported:
1491 - gdb.events.cont Continue event.
1492 - gdb.events.exited Inferior exited event.
1493 - gdb.events.stop Signal received, and Breakpoint hit events.
1497 ** GDB now puts template parameters in scope when debugging in an
1498 instantiation. For example, if you have:
1500 template<int X> int func (void) { return X; }
1502 then if you step into func<5>, "print X" will show "5". This
1503 feature requires proper debuginfo support from the compiler; it
1504 was added to GCC 4.5.
1506 ** The motion commands "next", "finish", "until", and "advance" now
1507 work better when exceptions are thrown. In particular, GDB will
1508 no longer lose control of the inferior; instead, the GDB will
1509 stop the inferior at the point at which the exception is caught.
1510 This functionality requires a change in the exception handling
1511 code that was introduced in GCC 4.5.
1513 * GDB now follows GCC's rules on accessing volatile objects when
1514 reading or writing target state during expression evaluation.
1515 One notable difference to prior behavior is that "print x = 0"
1516 no longer generates a read of x; the value of the assignment is
1517 now always taken directly from the value being assigned.
1519 * GDB now has some support for using labels in the program's source in
1520 linespecs. For instance, you can use "advance label" to continue
1521 execution to a label.
1523 * GDB now has support for reading and writing a new .gdb_index
1524 section. This section holds a fast index of DWARF debugging
1525 information and can be used to greatly speed up GDB startup and
1526 operation. See the documentation for `save gdb-index' for details.
1528 * The "watch" command now accepts an optional "-location" argument.
1529 When used, this causes GDB to watch the memory referred to by the
1530 expression. Such a watchpoint is never deleted due to it going out
1533 * GDB now supports thread debugging of core dumps on GNU/Linux.
1535 GDB now activates thread debugging using the libthread_db library
1536 when debugging GNU/Linux core dumps, similarly to when debugging
1537 live processes. As a result, when debugging a core dump file, GDB
1538 is now able to display pthread_t ids of threads. For example, "info
1539 threads" shows the same output as when debugging the process when it
1540 was live. In earlier releases, you'd see something like this:
1543 * 1 LWP 6780 main () at main.c:10
1545 While now you see this:
1548 * 1 Thread 0x7f0f5712a700 (LWP 6780) main () at main.c:10
1550 It is also now possible to inspect TLS variables when debugging core
1553 When debugging a core dump generated on a machine other than the one
1554 used to run GDB, you may need to point GDB at the correct
1555 libthread_db library with the "set libthread-db-search-path"
1556 command. See the user manual for more details on this command.
1558 * When natively debugging programs on PowerPC BookE processors running
1559 a Linux kernel version 2.6.34 or later, GDB supports ranged breakpoints,
1560 which stop execution of the inferior whenever it executes an instruction
1561 at any address within the specified range. See the "PowerPC Embedded"
1562 section in the user manual for more details.
1564 * New features in the GDB remote stub, GDBserver
1566 ** GDBserver is now supported on PowerPC LynxOS (versions 4.x and 5.x),
1567 and i686 LynxOS (version 5.x).
1569 ** GDBserver is now supported on Blackfin Linux.
1571 * New native configurations
1573 ia64 HP-UX ia64-*-hpux*
1577 Analog Devices, Inc. Blackfin Processor bfin-*
1579 * Ada task switching is now supported on sparc-elf targets when
1580 debugging a program using the Ravenscar Profile. For more information,
1581 see the "Tasking Support when using the Ravenscar Profile" section
1582 in the GDB user manual.
1584 * Guile support was removed.
1586 * New features in the GNU simulator
1588 ** The --map-info flag lists all known core mappings.
1590 ** CFI flashes may be simulated via the "cfi" device.
1592 *** Changes in GDB 7.2
1594 * Shared library support for remote targets by default
1596 When GDB is configured for a generic, non-OS specific target, like
1597 for example, --target=arm-eabi or one of the many *-*-elf targets,
1598 GDB now queries remote stubs for loaded shared libraries using the
1599 `qXfer:libraries:read' packet. Previously, shared library support
1600 was always disabled for such configurations.
1604 ** Argument Dependent Lookup (ADL)
1606 In C++ ADL lookup directs function search to the namespaces of its
1607 arguments even if the namespace has not been imported.
1617 Here the compiler will search for `foo' in the namespace of 'b'
1618 and find A::foo. GDB now supports this. This construct is commonly
1619 used in the Standard Template Library for operators.
1621 ** Improved User Defined Operator Support
1623 In addition to member operators, GDB now supports lookup of operators
1624 defined in a namespace and imported with a `using' directive, operators
1625 defined in the global scope, operators imported implicitly from an
1626 anonymous namespace, and the ADL operators mentioned in the previous
1628 GDB now also supports proper overload resolution for all the previously
1629 mentioned flavors of operators.
1631 ** static const class members
1633 Printing of static const class members that are initialized in the
1634 class definition has been fixed.
1636 * Windows Thread Information Block access.
1638 On Windows targets, GDB now supports displaying the Windows Thread
1639 Information Block (TIB) structure. This structure is visible either
1640 by using the new command `info w32 thread-information-block' or, by
1641 dereferencing the new convenience variable named `$_tlb', a
1642 thread-specific pointer to the TIB. This feature is also supported
1643 when remote debugging using GDBserver.
1645 * Static tracepoints
1647 Static tracepoints are calls in the user program into a tracing
1648 library. One such library is a port of the LTTng kernel tracer to
1649 userspace --- UST (LTTng Userspace Tracer, http://lttng.org/ust).
1650 When debugging with GDBserver, GDB now supports combining the GDB
1651 tracepoint machinery with such libraries. For example: the user can
1652 use GDB to probe a static tracepoint marker (a call from the user
1653 program into the tracing library) with the new "strace" command (see
1654 "New commands" below). This creates a "static tracepoint" in the
1655 breakpoint list, that can be manipulated with the same feature set
1656 as fast and regular tracepoints. E.g., collect registers, local and
1657 global variables, collect trace state variables, and define
1658 tracepoint conditions. In addition, the user can collect extra
1659 static tracepoint marker specific data, by collecting the new
1660 $_sdata internal variable. When analyzing the trace buffer, you can
1661 inspect $_sdata like any other variable available to GDB. For more
1662 information, see the "Tracepoints" chapter in GDB user manual. New
1663 remote packets have been defined to support static tracepoints, see
1664 the "New remote packets" section below.
1666 * Better reconstruction of tracepoints after disconnected tracing
1668 GDB will attempt to download the original source form of tracepoint
1669 definitions when starting a trace run, and then will upload these
1670 upon reconnection to the target, resulting in a more accurate
1671 reconstruction of the tracepoints that are in use on the target.
1675 You can now exercise direct control over the ways that GDB can
1676 affect your program. For instance, you can disallow the setting of
1677 breakpoints, so that the program can run continuously (assuming
1678 non-stop mode). In addition, the "observer" variable is available
1679 to switch all of the different controls; in observer mode, GDB
1680 cannot affect the target's behavior at all, which is useful for
1681 tasks like diagnosing live systems in the field.
1683 * The new convenience variable $_thread holds the number of the
1686 * New remote packets
1690 Return the address of the Windows Thread Information Block of a given thread.
1694 In response to several of the tracepoint packets, the target may now
1695 also respond with a number of intermediate `qRelocInsn' request
1696 packets before the final result packet, to have GDB handle
1697 relocating an instruction to execute at a different address. This
1698 is particularly useful for stubs that support fast tracepoints. GDB
1699 reports support for this feature in the qSupported packet.
1703 List static tracepoint markers in the target program.
1707 List static tracepoint markers at a given address in the target
1710 qXfer:statictrace:read
1712 Read the static trace data collected (by a `collect $_sdata'
1713 tracepoint action). The remote stub reports support for this packet
1714 to gdb's qSupported query.
1718 Send the current settings of GDB's permission flags.
1722 Send part of the source (textual) form of a tracepoint definition,
1723 which includes location, conditional, and action list.
1725 * The source command now accepts a -s option to force searching for the
1726 script in the source search path even if the script name specifies
1729 * New features in the GDB remote stub, GDBserver
1731 - GDBserver now support tracepoints (including fast tracepoints, and
1732 static tracepoints). The feature is currently supported by the
1733 i386-linux and amd64-linux builds. See the "Tracepoints support
1734 in gdbserver" section in the manual for more information.
1736 GDBserver JIT compiles the tracepoint's conditional agent
1737 expression bytecode into native code whenever possible for low
1738 overhead dynamic tracepoints conditionals. For such tracepoints,
1739 an expression that examines program state is evaluated when the
1740 tracepoint is reached, in order to determine whether to capture
1741 trace data. If the condition is simple and false, processing the
1742 tracepoint finishes very quickly and no data is gathered.
1744 GDBserver interfaces with the UST (LTTng Userspace Tracer) library
1745 for static tracepoints support.
1747 - GDBserver now supports x86_64 Windows 64-bit debugging.
1749 * GDB now sends xmlRegisters= in qSupported packet to indicate that
1750 it understands register description.
1752 * The --batch flag now disables pagination and queries.
1754 * X86 general purpose registers
1756 GDB now supports reading/writing byte, word and double-word x86
1757 general purpose registers directly. This means you can use, say,
1758 $ah or $ax to refer, respectively, to the byte register AH and
1759 16-bit word register AX that are actually portions of the 32-bit
1760 register EAX or 64-bit register RAX.
1762 * The `commands' command now accepts a range of breakpoints to modify.
1763 A plain `commands' following a command that creates multiple
1764 breakpoints affects all the breakpoints set by that command. This
1765 applies to breakpoints set by `rbreak', and also applies when a
1766 single `break' command creates multiple breakpoints (e.g.,
1767 breakpoints on overloaded c++ functions).
1769 * The `rbreak' command now accepts a filename specification as part of
1770 its argument, limiting the functions selected by the regex to those
1771 in the specified file.
1773 * Support for remote debugging Windows and SymbianOS shared libraries
1774 from Unix hosts has been improved. Non Windows GDB builds now can
1775 understand target reported file names that follow MS-DOS based file
1776 system semantics, such as file names that include drive letters and
1777 use the backslash character as directory separator. This makes it
1778 possible to transparently use the "set sysroot" and "set
1779 solib-search-path" on Unix hosts to point as host copies of the
1780 target's shared libraries. See the new command "set
1781 target-file-system-kind" described below, and the "Commands to
1782 specify files" section in the user manual for more information.
1786 eval template, expressions...
1787 Convert the values of one or more expressions under the control
1788 of the string template to a command line, and call it.
1790 set target-file-system-kind unix|dos-based|auto
1791 show target-file-system-kind
1792 Set or show the assumed file system kind for target reported file
1795 save breakpoints <filename>
1796 Save all current breakpoint definitions to a file suitable for use
1797 in a later debugging session. To read the saved breakpoint
1798 definitions, use the `source' command.
1800 `save tracepoints' is a new alias for `save-tracepoints'. The latter
1803 info static-tracepoint-markers
1804 Display information about static tracepoint markers in the target.
1806 strace FN | FILE:LINE | *ADDR | -m MARKER_ID
1807 Define a static tracepoint by probing a marker at the given
1808 function, line, address, or marker ID.
1812 Enable and disable observer mode.
1814 set may-write-registers on|off
1815 set may-write-memory on|off
1816 set may-insert-breakpoints on|off
1817 set may-insert-tracepoints on|off
1818 set may-insert-fast-tracepoints on|off
1819 set may-interrupt on|off
1820 Set individual permissions for GDB effects on the target. Note that
1821 some of these settings can have undesirable or surprising
1822 consequences, particularly when changed in the middle of a session.
1823 For instance, disabling the writing of memory can prevent
1824 breakpoints from being inserted, cause single-stepping to fail, or
1825 even crash your program, if you disable after breakpoints have been
1826 inserted. However, GDB should not crash.
1828 set record memory-query on|off
1829 show record memory-query
1830 Control whether to stop the inferior if memory changes caused
1831 by an instruction cannot be recorded.
1836 The disassemble command now supports "start,+length" form of two arguments.
1840 ** GDB now provides a new directory location, called the python directory,
1841 where Python scripts written for GDB can be installed. The location
1842 of that directory is <data-directory>/python, where <data-directory>
1843 is the GDB data directory. For more details, see section `Scripting
1844 GDB using Python' in the manual.
1846 ** The GDB Python API now has access to breakpoints, symbols, symbol
1847 tables, program spaces, inferiors, threads and frame's code blocks.
1848 Additionally, GDB Parameters can now be created from the API, and
1849 manipulated via set/show in the CLI.
1851 ** New functions gdb.target_charset, gdb.target_wide_charset,
1852 gdb.progspaces, gdb.current_progspace, and gdb.string_to_argv.
1854 ** New exception gdb.GdbError.
1856 ** Pretty-printers are now also looked up in the current program space.
1858 ** Pretty-printers can now be individually enabled and disabled.
1860 ** GDB now looks for names of Python scripts to auto-load in a
1861 special section named `.debug_gdb_scripts', in addition to looking
1862 for a OBJFILE-gdb.py script when OBJFILE is read by the debugger.
1864 * Tracepoint actions were unified with breakpoint commands. In particular,
1865 there are no longer differences in "info break" output for breakpoints and
1866 tracepoints and the "commands" command can be used for both tracepoints and
1867 regular breakpoints.
1871 ARM Symbian arm*-*-symbianelf*
1873 * D language support.
1874 GDB now supports debugging programs written in the D programming
1877 * GDB now supports the extended ptrace interface for PowerPC which is
1878 available since Linux kernel version 2.6.34. This automatically enables
1879 any hardware breakpoints and additional hardware watchpoints available in
1880 the processor. The old ptrace interface exposes just one hardware
1881 watchpoint and no hardware breakpoints.
1883 * GDB is now able to use the Data Value Compare (DVC) register available on
1884 embedded PowerPC processors to implement in hardware simple watchpoint
1885 conditions of the form:
1887 watch ADDRESS|VARIABLE if ADDRESS|VARIABLE == CONSTANT EXPRESSION
1889 This works in native GDB running on Linux kernels with the extended ptrace
1890 interface mentioned above.
1892 *** Changes in GDB 7.1
1896 ** Namespace Support
1898 GDB now supports importing of namespaces in C++. This enables the
1899 user to inspect variables from imported namespaces. Support for
1900 namepace aliasing has also been added. So, if a namespace is
1901 aliased in the current scope (e.g. namepace C=A; ) the user can
1902 print variables using the alias (e.g. (gdb) print C::x).
1906 All known bugs relating to the printing of virtual base class were
1907 fixed. It is now possible to call overloaded static methods using a
1912 The C++ cast operators static_cast<>, dynamic_cast<>, const_cast<>,
1913 and reinterpret_cast<> are now handled by the C++ expression parser.
1917 Xilinx MicroBlaze microblaze-*-*
1922 Xilinx MicroBlaze microblaze
1925 * Multi-program debugging.
1927 GDB now has support for multi-program (a.k.a. multi-executable or
1928 multi-exec) debugging. This allows for debugging multiple inferiors
1929 simultaneously each running a different program under the same GDB
1930 session. See "Debugging Multiple Inferiors and Programs" in the
1931 manual for more information. This implied some user visible changes
1932 in the multi-inferior support. For example, "info inferiors" now
1933 lists inferiors that are not running yet or that have exited
1934 already. See also "New commands" and "New options" below.
1936 * New tracing features
1938 GDB's tracepoint facility now includes several new features:
1940 ** Trace state variables
1942 GDB tracepoints now include support for trace state variables, which
1943 are variables managed by the target agent during a tracing
1944 experiment. They are useful for tracepoints that trigger each
1945 other, so for instance one tracepoint can count hits in a variable,
1946 and then a second tracepoint has a condition that is true when the
1947 count reaches a particular value. Trace state variables share the
1948 $-syntax of GDB convenience variables, and can appear in both
1949 tracepoint actions and condition expressions. Use the "tvariable"
1950 command to create, and "info tvariables" to view; see "Trace State
1951 Variables" in the manual for more detail.
1955 GDB now includes an option for defining fast tracepoints, which
1956 targets may implement more efficiently, such as by installing a jump
1957 into the target agent rather than a trap instruction. The resulting
1958 speedup can be by two orders of magnitude or more, although the
1959 tradeoff is that some program locations on some target architectures
1960 might not allow fast tracepoint installation, for instance if the
1961 instruction to be replaced is shorter than the jump. To request a
1962 fast tracepoint, use the "ftrace" command, with syntax identical to
1963 the regular trace command.
1965 ** Disconnected tracing
1967 It is now possible to detach GDB from the target while it is running
1968 a trace experiment, then reconnect later to see how the experiment
1969 is going. In addition, a new variable disconnected-tracing lets you
1970 tell the target agent whether to continue running a trace if the
1971 connection is lost unexpectedly.
1975 GDB now has the ability to save the trace buffer into a file, and
1976 then use that file as a target, similarly to you can do with
1977 corefiles. You can select trace frames, print data that was
1978 collected in them, and use tstatus to display the state of the
1979 tracing run at the moment that it was saved. To create a trace
1980 file, use "tsave <filename>", and to use it, do "target tfile
1983 ** Circular trace buffer
1985 You can ask the target agent to handle the trace buffer as a
1986 circular buffer, discarding the oldest trace frames to make room for
1987 newer ones, by setting circular-trace-buffer to on. This feature may
1988 not be available for all target agents.
1993 The disassemble command, when invoked with two arguments, now requires
1994 the arguments to be comma-separated.
1997 The info variables command now displays variable definitions. Files
1998 which only declare a variable are not shown.
2001 The source command is now capable of sourcing Python scripts.
2002 This feature is dependent on the debugger being build with Python
2005 Related to this enhancement is also the introduction of a new command
2006 "set script-extension" (see below).
2008 * New commands (for set/show, see "New options" below)
2010 record save [<FILENAME>]
2011 Save a file (in core file format) containing the process record
2012 execution log for replay debugging at a later time.
2014 record restore <FILENAME>
2015 Restore the process record execution log that was saved at an
2016 earlier time, for replay debugging.
2018 add-inferior [-copies <N>] [-exec <FILENAME>]
2021 clone-inferior [-copies <N>] [ID]
2022 Make a new inferior ready to execute the same program another
2023 inferior has loaded.
2028 maint info program-spaces
2029 List the program spaces loaded into GDB.
2031 set remote interrupt-sequence [Ctrl-C | BREAK | BREAK-g]
2032 show remote interrupt-sequence
2033 Allow the user to select one of ^C, a BREAK signal or BREAK-g
2034 as the sequence to the remote target in order to interrupt the execution.
2035 Ctrl-C is a default. Some system prefers BREAK which is high level of
2036 serial line for some certain time. Linux kernel prefers BREAK-g, a.k.a
2037 Magic SysRq g. It is BREAK signal and character 'g'.
2039 set remote interrupt-on-connect [on | off]
2040 show remote interrupt-on-connect
2041 When interrupt-on-connect is ON, gdb sends interrupt-sequence to
2042 remote target when gdb connects to it. This is needed when you debug
2045 set remotebreak [on | off]
2047 Deprecated. Use "set/show remote interrupt-sequence" instead.
2049 tvariable $NAME [ = EXP ]
2050 Create or modify a trace state variable.
2053 List trace state variables and their values.
2055 delete tvariable $NAME ...
2056 Delete one or more trace state variables.
2059 Evaluate the given expressions without collecting anything into the
2060 trace buffer. (Valid in tracepoint actions only.)
2062 ftrace FN / FILE:LINE / *ADDR
2063 Define a fast tracepoint at the given function, line, or address.
2065 * New expression syntax
2067 GDB now parses the 0b prefix of binary numbers the same way as GCC does.
2068 GDB now parses 0b101010 identically with 42.
2072 set follow-exec-mode new|same
2073 show follow-exec-mode
2074 Control whether GDB reuses the same inferior across an exec call or
2075 creates a new one. This is useful to be able to restart the old
2076 executable after the inferior having done an exec call.
2078 set default-collect EXPR, ...
2079 show default-collect
2080 Define a list of expressions to be collected at each tracepoint.
2081 This is a useful way to ensure essential items are not overlooked,
2082 such as registers or a critical global variable.
2084 set disconnected-tracing
2085 show disconnected-tracing
2086 If set to 1, the target is instructed to continue tracing if it
2087 loses its connection to GDB. If 0, the target is to stop tracing
2090 set circular-trace-buffer
2091 show circular-trace-buffer
2092 If set to on, the target is instructed to use a circular trace buffer
2093 and discard the oldest trace frames instead of stopping the trace due
2094 to a full trace buffer. If set to off, the trace stops when the buffer
2095 fills up. Some targets may not support this.
2097 set script-extension off|soft|strict
2098 show script-extension
2099 If set to "off", the debugger does not perform any script language
2100 recognition, and all sourced files are assumed to be GDB scripts.
2101 If set to "soft" (the default), files are sourced according to
2102 filename extension, falling back to GDB scripts if the first
2104 If set to "strict", files are sourced according to filename extension.
2106 set ada trust-PAD-over-XVS on|off
2107 show ada trust-PAD-over-XVS
2108 If off, activate a workaround against a bug in the debugging information
2109 generated by the compiler for PAD types (see gcc/exp_dbug.ads in
2110 the GCC sources for more information about the GNAT encoding and
2111 PAD types in particular). It is always safe to set this option to
2112 off, but this introduces a slight performance penalty. The default
2115 * Python API Improvements
2117 ** GDB provides the new class gdb.LazyString. This is useful in
2118 some pretty-printing cases. The new method gdb.Value.lazy_string
2119 provides a simple way to create objects of this type.
2121 ** The fields returned by gdb.Type.fields now have an
2122 `is_base_class' attribute.
2124 ** The new method gdb.Type.range returns the range of an array type.
2126 ** The new method gdb.parse_and_eval can be used to parse and
2127 evaluate an expression.
2129 * New remote packets
2132 Define a trace state variable.
2135 Get the current value of a trace state variable.
2138 Set desired tracing behavior upon disconnection.
2141 Set the trace buffer to be linear or circular.
2144 Get data about the tracepoints currently in use.
2148 Process record now works correctly with hardware watchpoints.
2150 Multiple bug fixes have been made to the mips-irix port, making it
2151 much more reliable. In particular:
2152 - Debugging threaded applications is now possible again. Previously,
2153 GDB would hang while starting the program, or while waiting for
2154 the program to stop at a breakpoint.
2155 - Attaching to a running process no longer hangs.
2156 - An error occurring while loading a core file has been fixed.
2157 - Changing the value of the PC register now works again. This fixes
2158 problems observed when using the "jump" command, or when calling
2159 a function from GDB, or even when assigning a new value to $pc.
2160 - With the "finish" and "return" commands, the return value for functions
2161 returning a small array is now correctly printed.
2162 - It is now possible to break on shared library code which gets executed
2163 during a shared library init phase (code executed while executing
2164 their .init section). Previously, the breakpoint would have no effect.
2165 - GDB is now able to backtrace through the signal handler for
2166 non-threaded programs.
2168 PIE (Position Independent Executable) programs debugging is now supported.
2169 This includes debugging execution of PIC (Position Independent Code) shared
2170 libraries although for that, it should be possible to run such libraries as an
2173 *** Changes in GDB 7.0
2175 * GDB now has an interface for JIT compilation. Applications that
2176 dynamically generate code can create symbol files in memory and register
2177 them with GDB. For users, the feature should work transparently, and
2178 for JIT developers, the interface is documented in the GDB manual in the
2179 "JIT Compilation Interface" chapter.
2181 * Tracepoints may now be conditional. The syntax is as for
2182 breakpoints; either an "if" clause appended to the "trace" command,
2183 or the "condition" command is available. GDB sends the condition to
2184 the target for evaluation using the same bytecode format as is used
2185 for tracepoint actions.
2187 * The disassemble command now supports: an optional /r modifier, print the
2188 raw instructions in hex as well as in symbolic form, and an optional /m
2189 modifier to print mixed source+assembly.
2191 * Process record and replay
2193 In a architecture environment that supports ``process record and
2194 replay'', ``process record and replay'' target can record a log of
2195 the process execution, and replay it with both forward and reverse
2198 * Reverse debugging: GDB now has new commands reverse-continue, reverse-
2199 step, reverse-next, reverse-finish, reverse-stepi, reverse-nexti, and
2200 set execution-direction {forward|reverse}, for targets that support
2203 * GDB now supports hardware watchpoints on MIPS/Linux systems. This
2204 feature is available with a native GDB running on kernel version
2207 * GDB now has support for multi-byte and wide character sets on the
2208 target. Strings whose character type is wchar_t, char16_t, or
2209 char32_t are now correctly printed. GDB supports wide- and unicode-
2210 literals in C, that is, L'x', L"string", u'x', u"string", U'x', and
2211 U"string" syntax. And, GDB allows the "%ls" and "%lc" formats in
2212 `printf'. This feature requires iconv to work properly; if your
2213 system does not have a working iconv, GDB can use GNU libiconv. See
2214 the installation instructions for more information.
2216 * GDB now supports automatic retrieval of shared library files from
2217 remote targets. To use this feature, specify a system root that begins
2218 with the `remote:' prefix, either via the `set sysroot' command or via
2219 the `--with-sysroot' configure-time option.
2221 * "info sharedlibrary" now takes an optional regex of libraries to show,
2222 and it now reports if a shared library has no debugging information.
2224 * Commands `set debug-file-directory', `set solib-search-path' and `set args'
2225 now complete on file names.
2227 * When completing in expressions, gdb will attempt to limit
2228 completions to allowable structure or union fields, where appropriate.
2229 For instance, consider:
2231 # struct example { int f1; double f2; };
2232 # struct example variable;
2235 If the user types TAB at the end of this command line, the available
2236 completions will be "f1" and "f2".
2238 * Inlined functions are now supported. They show up in backtraces, and
2239 the "step", "next", and "finish" commands handle them automatically.
2241 * GDB now supports the token-splicing (##) and stringification (#)
2242 operators when expanding macros. It also supports variable-arity
2245 * GDB now supports inspecting extra signal information, exported by
2246 the new $_siginfo convenience variable. The feature is currently
2247 implemented on linux ARM, i386 and amd64.
2249 * GDB can now display the VFP floating point registers and NEON vector
2250 registers on ARM targets. Both ARM GNU/Linux native GDB and gdbserver
2251 can provide these registers (requires Linux 2.6.30 or later). Remote
2252 and simulator targets may also provide them.
2254 * New remote packets
2257 Search memory for a sequence of bytes.
2260 Turn off `+'/`-' protocol acknowledgments to permit more efficient
2261 operation over reliable transport links. Use of this packet is
2262 controlled by the `set remote noack-packet' command.
2265 Kill the process with the specified process ID. Use this in preference
2266 to `k' when multiprocess protocol extensions are supported.
2269 Obtains additional operating system information
2273 Read or write additional signal information.
2275 * Removed remote protocol undocumented extension
2277 An undocumented extension to the remote protocol's `S' stop reply
2278 packet that permited the stub to pass a process id was removed.
2279 Remote servers should use the `T' stop reply packet instead.
2281 * GDB now supports multiple function calling conventions according to the
2282 DWARF-2 DW_AT_calling_convention function attribute.
2284 * The SH target utilizes the aforementioned change to distinguish between gcc
2285 and Renesas calling convention. It also adds the new CLI commands
2286 `set/show sh calling-convention'.
2288 * GDB can now read compressed debug sections, as produced by GNU gold
2289 with the --compress-debug-sections=zlib flag.
2291 * 64-bit core files are now supported on AIX.
2293 * Thread switching is now supported on Tru64.
2295 * Watchpoints can now be set on unreadable memory locations, e.g. addresses
2296 which will be allocated using malloc later in program execution.
2298 * The qXfer:libraries:read remote procotol packet now allows passing a
2299 list of section offsets.
2301 * On GNU/Linux, GDB can now attach to stopped processes. Several race
2302 conditions handling signals delivered during attach or thread creation
2303 have also been fixed.
2305 * GDB now supports the use of DWARF boolean types for Ada's type Boolean.
2306 From the user's standpoint, all unqualified instances of True and False
2307 are treated as the standard definitions, regardless of context.
2309 * GDB now parses C++ symbol and type names more flexibly. For
2312 template<typename T> class C { };
2315 GDB will now correctly handle all of:
2317 ptype C<char const *>
2318 ptype C<char const*>
2319 ptype C<const char *>
2320 ptype C<const char*>
2322 * New features in the GDB remote stub, gdbserver
2324 - The "--wrapper" command-line argument tells gdbserver to use a
2325 wrapper program to launch programs for debugging.
2327 - On PowerPC and S/390 targets, it is now possible to use a single
2328 gdbserver executable to debug both 32-bit and 64-bit programs.
2329 (This requires gdbserver itself to be built as a 64-bit executable.)
2331 - gdbserver uses the new noack protocol mode for TCP connections to
2332 reduce communications latency, if also supported and enabled in GDB.
2334 - Support for the sparc64-linux-gnu target is now included in
2337 - The amd64-linux build of gdbserver now supports debugging both
2338 32-bit and 64-bit programs.
2340 - The i386-linux, amd64-linux, and i386-win32 builds of gdbserver
2341 now support hardware watchpoints, and will use them automatically
2346 GDB now has support for scripting using Python. Whether this is
2347 available is determined at configure time.
2349 New GDB commands can now be written in Python.
2351 * Ada tasking support
2353 Ada tasks can now be inspected in GDB. The following commands have
2357 Print the list of Ada tasks.
2359 Print detailed information about task number N.
2361 Print the task number of the current task.
2363 Switch the context of debugging to task number N.
2365 * Support for user-defined prefixed commands. The "define" command can
2366 add new commands to existing prefixes, e.g. "target".
2368 * Multi-inferior, multi-process debugging.
2370 GDB now has generalized support for multi-inferior debugging. See
2371 "Debugging Multiple Inferiors" in the manual for more information.
2372 Although availability still depends on target support, the command
2373 set is more uniform now. The GNU/Linux specific multi-forks support
2374 has been migrated to this new framework. This implied some user
2375 visible changes; see "New commands" and also "Removed commands"
2378 * Target descriptions can now describe the target OS ABI. See the
2379 "Target Description Format" section in the user manual for more
2382 * Target descriptions can now describe "compatible" architectures
2383 to indicate that the target can execute applications for a different
2384 architecture in addition to those for the main target architecture.
2385 See the "Target Description Format" section in the user manual for
2388 * Multi-architecture debugging.
2390 GDB now includes general supports for debugging applications on
2391 hybrid systems that use more than one single processor architecture
2392 at the same time. Each such hybrid architecture still requires
2393 specific support to be added. The only hybrid architecture supported
2394 in this version of GDB is the Cell Broadband Engine.
2396 * GDB now supports integrated debugging of Cell/B.E. applications that
2397 use both the PPU and SPU architectures. To enable support for hybrid
2398 Cell/B.E. debugging, you need to configure GDB to support both the
2399 powerpc-linux or powerpc64-linux and the spu-elf targets, using the
2400 --enable-targets configure option.
2402 * Non-stop mode debugging.
2404 For some targets, GDB now supports an optional mode of operation in
2405 which you can examine stopped threads while other threads continue
2406 to execute freely. This is referred to as non-stop mode, with the
2407 old mode referred to as all-stop mode. See the "Non-Stop Mode"
2408 section in the user manual for more information.
2410 To be able to support remote non-stop debugging, a remote stub needs
2411 to implement the non-stop mode remote protocol extensions, as
2412 described in the "Remote Non-Stop" section of the user manual. The
2413 GDB remote stub, gdbserver, has been adjusted to support these
2414 extensions on linux targets.
2416 * New commands (for set/show, see "New options" below)
2418 catch syscall [NAME(S) | NUMBER(S)]
2419 Catch system calls. Arguments, which should be names of system
2420 calls or their numbers, mean catch only those syscalls. Without
2421 arguments, every syscall will be caught. When the inferior issues
2422 any of the specified syscalls, GDB will stop and announce the system
2423 call, both when it is called and when its call returns. This
2424 feature is currently available with a native GDB running on the
2425 Linux Kernel, under the following architectures: x86, x86_64,
2426 PowerPC and PowerPC64.
2428 find [/size-char] [/max-count] start-address, end-address|+search-space-size,
2430 Search memory for a sequence of bytes.
2432 maint set python print-stack
2433 maint show python print-stack
2434 Show a stack trace when an error is encountered in a Python script.
2437 Invoke CODE by passing it to the Python interpreter.
2442 These allow macros to be defined, undefined, and listed
2446 Show operating system information about processes.
2449 List the inferiors currently under GDB's control.
2452 Switch focus to inferior number NUM.
2455 Detach from inferior number NUM.
2458 Kill inferior number NUM.
2462 set spu stop-on-load
2463 show spu stop-on-load
2464 Control whether to stop for new SPE threads during Cell/B.E. debugging.
2466 set spu auto-flush-cache
2467 show spu auto-flush-cache
2468 Control whether to automatically flush the software-managed cache
2469 during Cell/B.E. debugging.
2471 set sh calling-convention
2472 show sh calling-convention
2473 Control the calling convention used when calling SH target functions.
2476 show debug timestamp
2477 Control display of timestamps with GDB debugging output.
2479 set disassemble-next-line
2480 show disassemble-next-line
2481 Control display of disassembled source lines or instructions when
2484 set remote noack-packet
2485 show remote noack-packet
2486 Set/show the use of remote protocol QStartNoAckMode packet. See above
2487 under "New remote packets."
2489 set remote query-attached-packet
2490 show remote query-attached-packet
2491 Control use of remote protocol `qAttached' (query-attached) packet.
2493 set remote read-siginfo-object
2494 show remote read-siginfo-object
2495 Control use of remote protocol `qXfer:siginfo:read' (read-siginfo-object)
2498 set remote write-siginfo-object
2499 show remote write-siginfo-object
2500 Control use of remote protocol `qXfer:siginfo:write' (write-siginfo-object)
2503 set remote reverse-continue
2504 show remote reverse-continue
2505 Control use of remote protocol 'bc' (reverse-continue) packet.
2507 set remote reverse-step
2508 show remote reverse-step
2509 Control use of remote protocol 'bs' (reverse-step) packet.
2511 set displaced-stepping
2512 show displaced-stepping
2513 Control displaced stepping mode. Displaced stepping is a way to
2514 single-step over breakpoints without removing them from the debuggee.
2515 Also known as "out-of-line single-stepping".
2518 show debug displaced
2519 Control display of debugging info for displaced stepping.
2521 maint set internal-error
2522 maint show internal-error
2523 Control what GDB does when an internal error is detected.
2525 maint set internal-warning
2526 maint show internal-warning
2527 Control what GDB does when an internal warning is detected.
2532 Use a wrapper program to launch programs for debugging.
2534 set multiple-symbols (all|ask|cancel)
2535 show multiple-symbols
2536 The value of this variable can be changed to adjust the debugger behavior
2537 when an expression or a breakpoint location contains an ambiguous symbol
2538 name (an overloaded function name, for instance).
2540 set breakpoint always-inserted
2541 show breakpoint always-inserted
2542 Keep breakpoints always inserted in the target, as opposed to inserting
2543 them when resuming the target, and removing them when the target stops.
2544 This option can improve debugger performance on slow remote targets.
2546 set arm fallback-mode (arm|thumb|auto)
2547 show arm fallback-mode
2548 set arm force-mode (arm|thumb|auto)
2550 These commands control how ARM GDB determines whether instructions
2551 are ARM or Thumb. The default for both settings is auto, which uses
2552 the current CPSR value for instructions without symbols; previous
2553 versions of GDB behaved as if "set arm fallback-mode arm".
2555 set disable-randomization
2556 show disable-randomization
2557 Standalone programs run with the virtual address space randomization enabled
2558 by default on some platforms. This option keeps the addresses stable across
2559 multiple debugging sessions.
2563 Control whether other threads are stopped or not when some thread hits
2568 Requests that asynchronous execution is enabled in the target, if available.
2569 In this case, it's possible to resume target in the background, and interact
2570 with GDB while the target is running. "show target-async" displays the
2571 current state of asynchronous execution of the target.
2573 set target-wide-charset
2574 show target-wide-charset
2575 The target-wide-charset is the name of the character set that GDB
2576 uses when printing characters whose type is wchar_t.
2578 set tcp auto-retry (on|off)
2580 set tcp connect-timeout
2581 show tcp connect-timeout
2582 These commands allow GDB to retry failed TCP connections to a remote stub
2583 with a specified timeout period; this is useful if the stub is launched
2584 in parallel with GDB but may not be ready to accept connections immediately.
2586 set libthread-db-search-path
2587 show libthread-db-search-path
2588 Control list of directories which GDB will search for appropriate
2591 set schedule-multiple (on|off)
2592 show schedule-multiple
2593 Allow GDB to resume all threads of all processes or only threads of
2594 the current process.
2598 Use more aggressive caching for accesses to the stack. This improves
2599 performance of remote debugging (particularly backtraces) without
2600 affecting correctness.
2602 set interactive-mode (on|off|auto)
2603 show interactive-mode
2604 Control whether GDB runs in interactive mode (on) or not (off).
2605 When in interactive mode, GDB waits for the user to answer all
2606 queries. Otherwise, GDB does not wait and assumes the default
2607 answer. When set to auto (the default), GDB determines which
2608 mode to use based on the stdin settings.
2613 For program forks, this is replaced by the new more generic `info
2614 inferiors' command. To list checkpoints, you can still use the
2615 `info checkpoints' command, which was an alias for the `info forks'
2619 Replaced by the new `inferior' command. To switch between
2620 checkpoints, you can still use the `restart' command, which was an
2621 alias for the `fork' command.
2624 This is removed, since some targets don't have a notion of
2625 processes. To switch between processes, you can still use the
2626 `inferior' command using GDB's own inferior number.
2629 For program forks, this is replaced by the new more generic `kill
2630 inferior' command. To delete a checkpoint, you can still use the
2631 `delete checkpoint' command, which was an alias for the `delete
2635 For program forks, this is replaced by the new more generic `detach
2636 inferior' command. To detach a checkpoint, you can still use the
2637 `detach checkpoint' command, which was an alias for the `detach
2640 * New native configurations
2642 x86/x86_64 Darwin i[34567]86-*-darwin*
2644 x86_64 MinGW x86_64-*-mingw*
2648 Lattice Mico32 lm32-*
2649 x86 DICOS i[34567]86-*-dicos*
2650 x86_64 DICOS x86_64-*-dicos*
2653 * The GDB remote stub, gdbserver, now supports x86 Windows CE
2654 (mingw32ce) debugging.
2660 These commands were actually not implemented on any target.
2662 *** Changes in GDB 6.8
2664 * New native configurations
2666 NetBSD/hppa hppa*-*netbsd*
2667 Xtensa GNU/Linux xtensa*-*-linux*
2671 NetBSD/hppa hppa*-*-netbsd*
2672 Xtensa GNU/Lunux xtensa*-*-linux*
2674 * Change in command line behavior -- corefiles vs. process ids.
2676 When the '-p NUMBER' or '--pid NUMBER' options are used, and
2677 attaching to process NUMBER fails, GDB no longer attempts to open a
2678 core file named NUMBER. Attaching to a program using the -c option
2679 is no longer supported. Instead, use the '-p' or '--pid' options.
2681 * GDB can now be built as a native debugger for debugging Windows x86
2682 (mingw32) Portable Executable (PE) programs.
2684 * Pending breakpoints no longer change their number when their address
2687 * GDB now supports breakpoints with multiple locations,
2688 including breakpoints on C++ constructors, inside C++ templates,
2689 and in inlined functions.
2691 * GDB's ability to debug optimized code has been improved. GDB more
2692 accurately identifies function bodies and lexical blocks that occupy
2693 more than one contiguous range of addresses.
2695 * Target descriptions can now describe registers for PowerPC.
2697 * The GDB remote stub, gdbserver, now supports the AltiVec and SPE
2698 registers on PowerPC targets.
2700 * The GDB remote stub, gdbserver, now supports thread debugging on GNU/Linux
2701 targets even when the libthread_db library is not available.
2703 * The GDB remote stub, gdbserver, now supports the new file transfer
2704 commands (remote put, remote get, and remote delete).
2706 * The GDB remote stub, gdbserver, now supports run and attach in
2707 extended-remote mode.
2709 * hppa*64*-*-hpux11* target broken
2710 The debugger is unable to start a program and fails with the following
2711 error: "Error trying to get information about dynamic linker".
2712 The gdb-6.7 release is also affected.
2714 * GDB now supports the --enable-targets= configure option to allow
2715 building a single GDB executable that supports multiple remote
2716 target architectures.
2718 * GDB now supports debugging C and C++ programs which use the
2719 Decimal Floating Point extension. In addition, the PowerPC target
2720 now has a set of pseudo-registers to inspect decimal float values
2721 stored in two consecutive float registers.
2723 * The -break-insert MI command can optionally create pending
2726 * Improved support for debugging Ada
2727 Many improvements to the Ada language support have been made. These
2729 - Better support for Ada2005 interface types
2730 - Improved handling of arrays and slices in general
2731 - Better support for Taft-amendment types
2732 - The '{type} ADDRESS' expression is now allowed on the left hand-side
2734 - Improved command completion in Ada
2737 * GDB on GNU/Linux and HP/UX can now debug through "exec" of a new
2742 set print frame-arguments (all|scalars|none)
2743 show print frame-arguments
2744 The value of this variable can be changed to control which argument
2745 values should be printed by the debugger when displaying a frame.
2750 Transfer files to and from a remote target, and delete remote files.
2757 Transfer files to and from a remote target, and delete remote files.
2759 * New remote packets
2766 Open, close, read, write, and delete files on the remote system.
2769 Attach to an existing process on the remote system, in extended-remote
2773 Run a new process on the remote system, in extended-remote mode.
2775 *** Changes in GDB 6.7
2777 * Resolved 101 resource leaks, null pointer dereferences, etc. in gdb,
2778 bfd, libiberty and opcodes, as revealed by static analysis donated by
2779 Coverity, Inc. (http://scan.coverity.com).
2781 * When looking up multiply-defined global symbols, GDB will now prefer the
2782 symbol definition in the current shared library if it was built using the
2783 -Bsymbolic linker option.
2785 * When the Text User Interface (TUI) is not configured, GDB will now
2786 recognize the -tui command-line option and print a message that the TUI
2789 * The GDB remote stub, gdbserver, now has lower overhead for high
2790 frequency signals (e.g. SIGALRM) via the QPassSignals packet.
2792 * GDB for MIPS targets now autodetects whether a remote target provides
2793 32-bit or 64-bit register values.
2795 * Support for C++ member pointers has been improved.
2797 * GDB now understands XML target descriptions, which specify the
2798 target's overall architecture. GDB can read a description from
2799 a local file or over the remote serial protocol.
2801 * Vectors of single-byte data use a new integer type which is not
2802 automatically displayed as character or string data.
2804 * The /s format now works with the print command. It displays
2805 arrays of single-byte integers and pointers to single-byte integers
2808 * Target descriptions can now describe target-specific registers,
2809 for architectures which have implemented the support (currently
2810 only ARM, M68K, and MIPS).
2812 * GDB and the GDB remote stub, gdbserver, now support the XScale
2815 * The GDB remote stub, gdbserver, has been updated to support
2816 ARM Windows CE (mingw32ce) debugging, and GDB Windows CE support
2817 has been rewritten to use the standard GDB remote protocol.
2819 * GDB can now step into C++ functions which are called through thunks.
2821 * GDB for the Cell/B.E. SPU now supports overlay debugging.
2823 * The GDB remote protocol "qOffsets" packet can now honor ELF segment
2824 layout. It also supports a TextSeg= and DataSeg= response when only
2825 segment base addresses (rather than offsets) are available.
2827 * The /i format now outputs any trailing branch delay slot instructions
2828 immediately following the last instruction within the count specified.
2830 * The GDB remote protocol "T" stop reply packet now supports a
2831 "library" response. Combined with the new "qXfer:libraries:read"
2832 packet, this response allows GDB to debug shared libraries on targets
2833 where the operating system manages the list of loaded libraries (e.g.
2834 Windows and SymbianOS).
2836 * The GDB remote stub, gdbserver, now supports dynamic link libraries
2837 (DLLs) on Windows and Windows CE targets.
2839 * GDB now supports a faster verification that a .debug file matches its binary
2840 according to its build-id signature, if the signature is present.
2846 Enable or disable hardware flow control (RTS/CTS) on the serial port
2847 when debugging using remote targets.
2849 set mem inaccessible-by-default
2850 show mem inaccessible-by-default
2851 If the target supplies a memory map, for instance via the remote
2852 protocol's "qXfer:memory-map:read" packet, setting this variable
2853 prevents GDB from accessing memory outside the memory map. This
2854 is useful for targets with memory mapped registers or which react
2855 badly to accesses of unmapped address space.
2857 set breakpoint auto-hw
2858 show breakpoint auto-hw
2859 If the target supplies a memory map, for instance via the remote
2860 protocol's "qXfer:memory-map:read" packet, setting this variable
2861 lets GDB use hardware breakpoints automatically for memory regions
2862 where it can not use software breakpoints. This covers both the
2863 "break" command and internal breakpoints used for other commands
2864 including "next" and "finish".
2867 catch exception unhandled
2868 Stop the program execution when Ada exceptions are raised.
2871 Stop the program execution when an Ada assertion failed.
2875 Set an alternate system root for target files. This is a more
2876 general version of "set solib-absolute-prefix", which is now
2877 an alias to "set sysroot".
2880 Provide extended SPU facility status information. This set of
2881 commands is available only when debugging the Cell/B.E. SPU
2884 * New native configurations
2886 OpenBSD/sh sh*-*openbsd*
2889 unset tdesc filename
2891 Use the specified local file as an XML target description, and do
2892 not query the target for its built-in description.
2896 OpenBSD/sh sh*-*-openbsd*
2897 MIPS64 GNU/Linux (gdbserver) mips64-linux-gnu
2898 Toshiba Media Processor mep-elf
2900 * New remote packets
2903 Ignore the specified signals; pass them directly to the debugged program
2904 without stopping other threads or reporting them to GDB.
2906 qXfer:features:read:
2907 Read an XML target description from the target, which describes its
2912 Read or write contents of an spufs file on the target system. These
2913 packets are available only on the Cell/B.E. SPU architecture.
2915 qXfer:libraries:read:
2916 Report the loaded shared libraries. Combined with new "T" packet
2917 response, this packet allows GDB to debug shared libraries on
2918 targets where the operating system manages the list of loaded
2919 libraries (e.g. Windows and SymbianOS).
2923 Support for these obsolete configurations has been removed.
2931 i[34567]86-*-lynxos*
2932 i[34567]86-*-netware*
2933 i[34567]86-*-sco3.2v5*
2934 i[34567]86-*-sco3.2v4*
2936 i[34567]86-*-sysv4.2*
2939 i[34567]86-*-unixware2*
2940 i[34567]86-*-unixware*
2949 * Other removed features
2956 Various m68k-only ROM monitors.
2963 Various Renesas ROM monitors and debugging interfaces for SH and
2968 Support for a Macraigor serial interface to on-chip debugging.
2969 GDB does not directly support the newer parallel or USB
2974 A debug information format. The predecessor to DWARF 2 and
2975 DWARF 3, which are still supported.
2977 Support for the HP aCC compiler on HP-UX/PA-RISC
2979 SOM-encapsulated symbolic debugging information, automatic
2980 invocation of pxdb, and the aCC custom C++ ABI. This does not
2981 affect HP-UX for Itanium or GCC for HP-UX/PA-RISC. Code compiled
2982 with aCC can still be debugged on an assembly level.
2984 MIPS ".pdr" sections
2986 A MIPS-specific format used to describe stack frame layout
2987 in debugging information.
2991 GDB could work with an older version of Guile to debug
2992 the interpreter and Scheme programs running in it.
2994 set mips stack-arg-size
2995 set mips saved-gpreg-size
2997 Use "set mips abi" to control parameter passing for MIPS.
2999 *** Changes in GDB 6.6
3004 Cell Broadband Engine SPU spu-elf
3006 * GDB can now be configured as a cross-debugger targeting native Windows
3007 (mingw32) or Cygwin. It can communicate with a remote debugging stub
3008 running on a Windows system over TCP/IP to debug Windows programs.
3010 * The GDB remote stub, gdbserver, has been updated to support Windows and
3011 Cygwin debugging. Both single-threaded and multi-threaded programs are
3014 * The "set trust-readonly-sections" command works again. This command was
3015 broken in GDB 6.3, 6.4, and 6.5.
3017 * The "load" command now supports writing to flash memory, if the remote
3018 stub provides the required support.
3020 * Support for GNU/Linux Thread Local Storage (TLS, per-thread variables) no
3021 longer requires symbolic debug information (e.g. DWARF-2).
3026 unset substitute-path
3027 show substitute-path
3028 Manage a list of substitution rules that GDB uses to rewrite the name
3029 of the directories where the sources are located. This can be useful
3030 for instance when the sources were moved to a different location
3031 between compilation and debugging.
3035 Print each CLI command as it is executed. Each command is prefixed with
3036 a number of `+' symbols representing the nesting depth.
3037 The source command now has a `-v' option to enable the same feature.
3041 The ARM Demon monitor support (RDP protocol, "target rdp").
3043 Kernel Object Display, an embedded debugging feature which only worked with
3044 an obsolete version of Cisco IOS.
3046 The 'set download-write-size' and 'show download-write-size' commands.
3048 * New remote packets
3051 Tell a stub about GDB client features, and request remote target features.
3052 The first feature implemented is PacketSize, which allows the target to
3053 specify the size of packets it can handle - to minimize the number of
3054 packets required and improve performance when connected to a remote
3058 Fetch an OS auxilliary vector from the remote stub. This packet is a
3059 more efficient replacement for qPart:auxv:read.
3061 qXfer:memory-map:read:
3062 Fetch a memory map from the remote stub, including information about
3063 RAM, ROM, and flash memory devices.
3068 Erase and program a flash memory device.
3070 * Removed remote packets
3073 This packet has been replaced by qXfer:auxv:read. Only GDB 6.4 and 6.5
3074 used it, and only gdbserver implemented it.
3076 *** Changes in GDB 6.5
3080 Renesas M32C/M16C m32c-elf
3082 Morpho Technologies ms1 ms1-elf
3086 init-if-undefined Initialize a convenience variable, but
3087 only if it doesn't already have a value.
3089 The following commands are presently only implemented for native GNU/Linux:
3091 checkpoint Save a snapshot of the program state.
3093 restart <n> Return the program state to a
3094 previously saved state.
3096 info checkpoints List currently saved checkpoints.
3098 delete-checkpoint <n> Delete a previously saved checkpoint.
3100 set|show detach-on-fork Tell gdb whether to detach from a newly
3101 forked process, or to keep debugging it.
3103 info forks List forks of the user program that
3104 are available to be debugged.
3106 fork <n> Switch to debugging one of several
3107 forks of the user program that are
3108 available to be debugged.
3110 delete-fork <n> Delete a fork from the list of forks
3111 that are available to be debugged (and
3112 kill the forked process).
3114 detach-fork <n> Delete a fork from the list of forks
3115 that are available to be debugged (and
3116 allow the process to continue).
3120 Morpho Technologies ms2 ms1-elf
3122 * Improved Windows host support
3124 GDB now builds as a cross debugger hosted on i686-mingw32, including
3125 native console support, and remote communications using either
3126 network sockets or serial ports.
3128 * Improved Modula-2 language support
3130 GDB can now print most types in the Modula-2 syntax. This includes:
3131 basic types, set types, record types, enumerated types, range types,
3132 pointer types and ARRAY types. Procedure var parameters are correctly
3133 printed and hexadecimal addresses and character constants are also
3134 written in the Modula-2 syntax. Best results can be obtained by using
3135 GNU Modula-2 together with the -gdwarf-2 command line option.
3139 The ARM rdi-share module.
3141 The Netware NLM debug server.
3143 *** Changes in GDB 6.4
3145 * New native configurations
3147 OpenBSD/arm arm*-*-openbsd*
3148 OpenBSD/mips64 mips64-*-openbsd*
3152 Morpho Technologies ms1 ms1-elf
3154 * New command line options
3156 --batch-silent As for --batch, but totally silent.
3157 --return-child-result The debugger will exist with the same value
3158 the child (debugged) program exited with.
3159 --eval-command COMMAND, -ex COMMAND
3160 Execute a single GDB CLI command. This may be
3161 specified multiple times and in conjunction
3162 with the --command (-x) option.
3164 * Deprecated commands removed
3166 The following commands, that were deprecated in 2000, have been
3170 set|show arm disassembly-flavor set|show arm disassembler
3171 othernames set arm disassembler
3172 set|show remotedebug set|show debug remote
3173 set|show archdebug set|show debug arch
3174 set|show eventdebug set|show debug event
3177 * New BSD user-level threads support
3179 It is now possible to debug programs using the user-level threads
3180 library on OpenBSD and FreeBSD. Currently supported (target)
3183 FreeBSD/amd64 x86_64-*-freebsd*
3184 FreeBSD/i386 i386-*-freebsd*
3185 OpenBSD/i386 i386-*-openbsd*
3187 Note that the new kernel threads libraries introduced in FreeBSD 5.x
3188 are not yet supported.
3190 * New support for Matsushita MN10300 w/sim added
3191 (Work in progress). mn10300-elf.
3193 * REMOVED configurations and files
3195 VxWorks and the XDR protocol *-*-vxworks
3196 Motorola MCORE mcore-*-*
3197 National Semiconductor NS32000 ns32k-*-*
3199 * New "set print array-indexes" command
3201 After turning this setting "on", GDB prints the index of each element
3202 when displaying arrays. The default is "off" to preserve the previous
3205 * VAX floating point support
3207 GDB now supports the not-quite-ieee VAX F and D floating point formats.
3209 * User-defined command support
3211 In addition to using $arg0..$arg9 for argument passing, it is now possible
3212 to use $argc to determine now many arguments have been passed. See the
3213 section on user-defined commands in the user manual for more information.
3215 *** Changes in GDB 6.3:
3217 * New command line option
3219 GDB now accepts -l followed by a number to set the timeout for remote
3222 * GDB works with GCC -feliminate-dwarf2-dups
3224 GDB now supports a more compact representation of DWARF-2 debug
3225 information using DW_FORM_ref_addr references. These are produced
3226 by GCC with the option -feliminate-dwarf2-dups and also by some
3227 proprietary compilers. With GCC, you must use GCC 3.3.4 or later
3228 to use -feliminate-dwarf2-dups.
3230 * Internationalization
3232 When supported by the host system, GDB will be built with
3233 internationalization (libintl). The task of marking up the sources is
3234 continued, we're looking forward to our first translation.
3238 Initial support for debugging programs compiled with the GNAT
3239 implementation of the Ada programming language has been integrated
3240 into GDB. In this release, support is limited to expression evaluation.
3242 * New native configurations
3244 GNU/Linux/m32r m32r-*-linux-gnu
3248 GDB's remote protocol now includes support for the 'p' packet. This
3249 packet is used to fetch individual registers from a remote inferior.
3251 * END-OF-LIFE registers[] compatibility module
3253 GDB's internal register infrastructure has been completely rewritten.
3254 The new infrastructure making possible the implementation of key new
3255 features including 32x64 (e.g., 64-bit amd64 GDB debugging a 32-bit
3258 GDB 6.3 will be the last release to include the the registers[]
3259 compatibility module that allowed out-of-date configurations to
3260 continue to work. This change directly impacts the following
3270 powerpc bdm protocol
3272 Unless there is activity to revive these configurations, they will be
3273 made OBSOLETE in GDB 6.4, and REMOVED from GDB 6.5.
3275 * OBSOLETE configurations and files
3277 Configurations that have been declared obsolete in this release have
3278 been commented out. Unless there is activity to revive these
3279 configurations, the next release of GDB will have their sources
3280 permanently REMOVED.
3289 *** Changes in GDB 6.2.1:
3291 * MIPS `break main; run' gave an heuristic-fence-post warning
3293 When attempting to run even a simple program, a warning about
3294 heuristic-fence-post being hit would be reported. This problem has
3297 * MIPS IRIX 'long double' crashed GDB
3299 When examining a long double variable, GDB would get a segmentation
3300 fault. The crash has been fixed (but GDB 6.2 cannot correctly examine
3301 IRIX long double values).
3305 A bug in the VAX stack code was causing problems with the "next"
3306 command. This problem has been fixed.
3308 *** Changes in GDB 6.2:
3310 * Fix for ``many threads''
3312 On GNU/Linux systems that use the NPTL threads library, a program
3313 rapidly creating and deleting threads would confuse GDB leading to the
3316 ptrace: No such process.
3317 thread_db_get_info: cannot get thread info: generic error
3319 This problem has been fixed.
3321 * "-async" and "-noasync" options removed.
3323 Support for the broken "-noasync" option has been removed (it caused
3326 * New ``start'' command.
3328 This command runs the program until the begining of the main procedure.
3330 * New BSD Kernel Data Access Library (libkvm) interface
3332 Using ``target kvm'' it is now possible to debug kernel core dumps and
3333 live kernel memory images on various FreeBSD, NetBSD and OpenBSD
3334 platforms. Currently supported (native-only) configurations are:
3336 FreeBSD/amd64 x86_64-*-freebsd*
3337 FreeBSD/i386 i?86-*-freebsd*
3338 NetBSD/i386 i?86-*-netbsd*
3339 NetBSD/m68k m68*-*-netbsd*
3340 NetBSD/sparc sparc-*-netbsd*
3341 OpenBSD/amd64 x86_64-*-openbsd*
3342 OpenBSD/i386 i?86-*-openbsd*
3343 OpenBSD/m68k m68*-openbsd*
3344 OpenBSD/sparc sparc-*-openbsd*
3346 * Signal trampoline code overhauled
3348 Many generic problems with GDB's signal handling code have been fixed.
3349 These include: backtraces through non-contiguous stacks; recognition
3350 of sa_sigaction signal trampolines; backtrace from a NULL pointer
3351 call; backtrace through a signal trampoline; step into and out of
3352 signal handlers; and single-stepping in the signal trampoline.
3354 Please note that kernel bugs are a limiting factor here. These
3355 features have been shown to work on an s390 GNU/Linux system that
3356 include a 2.6.8-rc1 kernel. Ref PR breakpoints/1702.
3358 * Cygwin support for DWARF 2 added.
3360 * New native configurations
3362 GNU/Linux/hppa hppa*-*-linux*
3363 OpenBSD/hppa hppa*-*-openbsd*
3364 OpenBSD/m68k m68*-*-openbsd*
3365 OpenBSD/m88k m88*-*-openbsd*
3366 OpenBSD/powerpc powerpc-*-openbsd*
3367 NetBSD/vax vax-*-netbsd*
3368 OpenBSD/vax vax-*-openbsd*
3370 * END-OF-LIFE frame compatibility module
3372 GDB's internal frame infrastructure has been completely rewritten.
3373 The new infrastructure making it possible to support key new features
3374 including DWARF 2 Call Frame Information. To aid in the task of
3375 migrating old configurations to this new infrastructure, a
3376 compatibility module, that allowed old configurations to continue to
3377 work, was also included.
3379 GDB 6.2 will be the last release to include this frame compatibility
3380 module. This change directly impacts the following configurations:
3390 Unless there is activity to revive these configurations, they will be
3391 made OBSOLETE in GDB 6.3, and REMOVED from GDB 6.4.
3393 * REMOVED configurations and files
3395 Sun 3, running SunOS 3 m68*-*-sunos3*
3396 Sun 3, running SunOS 4 m68*-*-sunos4*
3397 Sun 2, running SunOS 3 m68000-*-sunos3*
3398 Sun 2, running SunOS 4 m68000-*-sunos4*
3399 Motorola 680x0 running LynxOS m68*-*-lynxos*
3400 AT&T 3b1/Unix pc m68*-att-*
3401 Bull DPX2 (68k, System V release 3) m68*-bull-sysv*
3402 decstation mips-dec-* mips-little-*
3403 riscos mips-*-riscos* mips-*-sysv*
3404 sonymips mips-sony-*
3405 sysv mips*-*-sysv4* (IRIX 5/6 not included)
3407 *** Changes in GDB 6.1.1:
3409 * TUI (Text-mode User Interface) built-in (also included in GDB 6.1)
3411 The TUI (Text-mode User Interface) is now built as part of a default
3412 GDB configuration. It is enabled by either selecting the TUI with the
3413 command line option "-i=tui" or by running the separate "gdbtui"
3414 program. For more information on the TUI, see the manual "Debugging
3417 * Pending breakpoint support (also included in GDB 6.1)
3419 Support has been added to allow you to specify breakpoints in shared
3420 libraries that have not yet been loaded. If a breakpoint location
3421 cannot be found, and the "breakpoint pending" option is set to auto,
3422 GDB queries you if you wish to make the breakpoint pending on a future
3423 shared-library load. If and when GDB resolves the breakpoint symbol,
3424 the pending breakpoint is removed as one or more regular breakpoints
3427 Pending breakpoints are very useful for GCJ Java debugging.
3429 * Fixed ISO-C build problems
3431 The files bfd/elf-bfd.h, gdb/dictionary.c and gdb/types.c contained
3432 non ISO-C code that stopped them being built using a more strict ISO-C
3433 compiler (e.g., IBM's C compiler).
3435 * Fixed build problem on IRIX 5
3437 Due to header problems with <sys/proc.h>, the file gdb/proc-api.c
3438 wasn't able to compile compile on an IRIX 5 system.
3440 * Added execute permission to gdb/gdbserver/configure
3442 The shell script gdb/testsuite/gdb.stabs/configure lacked execute
3443 permission. This bug would cause configure to fail on a number of
3444 systems (Solaris, IRIX). Ref: server/519.
3446 * Fixed build problem on hpux2.0w-hp-hpux11.00 using the HP ANSI C compiler
3448 Older HPUX ANSI C compilers did not accept variable array sizes. somsolib.c
3449 has been updated to use constant array sizes.
3451 * Fixed a panic in the DWARF Call Frame Info code on Solaris 2.7
3453 GCC 3.3.2, on Solaris 2.7, includes the DW_EH_PE_funcrel encoding in
3454 its generated DWARF Call Frame Info. This encoding was causing GDB to
3455 panic, that panic has been fixed. Ref: gdb/1628.
3457 * Fixed a problem when examining parameters in shared library code.
3459 When examining parameters in optimized shared library code generated
3460 by a mainline GCC, GDB would incorrectly report ``Variable "..." is
3461 not available''. GDB now correctly displays the variable's value.
3463 *** Changes in GDB 6.1:
3465 * Removed --with-mmalloc
3467 Support for the mmalloc memory manager has been removed, as it
3468 conflicted with the internal gdb byte cache.
3470 * Changes in AMD64 configurations
3472 The AMD64 target now includes the %cs and %ss registers. As a result
3473 the AMD64 remote protocol has changed; this affects the floating-point
3474 and SSE registers. If you rely on those registers for your debugging,
3475 you should upgrade gdbserver on the remote side.
3477 * Revised SPARC target
3479 The SPARC target has been completely revised, incorporating the
3480 FreeBSD/sparc64 support that was added for GDB 6.0. As a result
3481 support for LynxOS and SunOS 4 has been dropped. Calling functions
3482 from within GDB on operating systems with a non-executable stack
3483 (Solaris, OpenBSD) now works.
3487 GDB has a new C++ demangler which does a better job on the mangled
3488 names generated by current versions of g++. It also runs faster, so
3489 with this and other changes gdb should now start faster on large C++
3492 * DWARF 2 Location Expressions
3494 GDB support for location expressions has been extended to support function
3495 arguments and frame bases. Older versions of GDB could crash when they
3498 * C++ nested types and namespaces
3500 GDB's support for nested types and namespaces in C++ has been
3501 improved, especially if you use the DWARF 2 debugging format. (This
3502 is the default for recent versions of GCC on most platforms.)
3503 Specifically, if you have a class "Inner" defined within a class or
3504 namespace "Outer", then GDB realizes that the class's name is
3505 "Outer::Inner", not simply "Inner". This should greatly reduce the
3506 frequency of complaints about not finding RTTI symbols. In addition,
3507 if you are stopped at inside of a function defined within a namespace,
3508 GDB modifies its name lookup accordingly.
3510 * New native configurations
3512 NetBSD/amd64 x86_64-*-netbsd*
3513 OpenBSD/amd64 x86_64-*-openbsd*
3514 OpenBSD/alpha alpha*-*-openbsd*
3515 OpenBSD/sparc sparc-*-openbsd*
3516 OpenBSD/sparc64 sparc64-*-openbsd*
3518 * New debugging protocols
3520 M32R with SDI protocol m32r-*-elf*
3522 * "set prompt-escape-char" command deleted.
3524 The command "set prompt-escape-char" has been deleted. This command,
3525 and its very obscure effet on GDB's prompt, was never documented,
3526 tested, nor mentioned in the NEWS file.
3528 * OBSOLETE configurations and files
3530 Configurations that have been declared obsolete in this release have
3531 been commented out. Unless there is activity to revive these
3532 configurations, the next release of GDB will have their sources
3533 permanently REMOVED.
3535 Sun 3, running SunOS 3 m68*-*-sunos3*
3536 Sun 3, running SunOS 4 m68*-*-sunos4*
3537 Sun 2, running SunOS 3 m68000-*-sunos3*
3538 Sun 2, running SunOS 4 m68000-*-sunos4*
3539 Motorola 680x0 running LynxOS m68*-*-lynxos*
3540 AT&T 3b1/Unix pc m68*-att-*
3541 Bull DPX2 (68k, System V release 3) m68*-bull-sysv*
3542 decstation mips-dec-* mips-little-*
3543 riscos mips-*-riscos* mips-*-sysv*
3544 sonymips mips-sony-*
3545 sysv mips*-*-sysv4* (IRIX 5/6 not included)
3547 * REMOVED configurations and files
3549 SGI Irix-4.x mips-sgi-irix4 or iris4
3550 SGI Iris (MIPS) running Irix V3: mips-sgi-irix or iris
3551 Z8000 simulator z8k-zilog-none or z8ksim
3552 Matsushita MN10200 w/simulator mn10200-*-*
3553 H8/500 simulator h8500-hitachi-hms or h8500hms
3554 HP/PA running BSD hppa*-*-bsd*
3555 HP/PA running OSF/1 hppa*-*-osf*
3556 HP/PA Pro target hppa*-*-pro*
3557 PMAX (MIPS) running Mach 3.0 mips*-*-mach3*
3558 386BSD i[3456]86-*-bsd*
3559 Sequent family i[3456]86-sequent-sysv4*
3560 i[3456]86-sequent-sysv*
3561 i[3456]86-sequent-bsd*
3562 SPARC running LynxOS sparc-*-lynxos*
3563 SPARC running SunOS 4 sparc-*-sunos4*
3564 Tsqware Sparclet sparclet-*-*
3565 Fujitsu SPARClite sparclite-fujitsu-none or sparclite
3567 *** Changes in GDB 6.0:
3571 Support for debugging the Objective-C programming language has been
3572 integrated into GDB.
3574 * New backtrace mechanism (includes DWARF 2 Call Frame Information).
3576 DWARF 2's Call Frame Information makes available compiler generated
3577 information that more exactly describes the program's run-time stack.
3578 By using this information, GDB is able to provide more robust stack
3581 The i386, amd64 (nee, x86-64), Alpha, m68hc11, ia64, and m32r targets
3582 have been updated to use a new backtrace mechanism which includes
3583 DWARF 2 CFI support.
3587 GDB's remote protocol has been extended to include support for hosted
3588 file I/O (where the remote target uses GDB's file system). See GDB's
3589 remote protocol documentation for details.
3591 * All targets using the new architecture framework.
3593 All of GDB's targets have been updated to use the new internal
3594 architecture framework. The way is now open for future GDB releases
3595 to include cross-architecture native debugging support (i386 on amd64,
3598 * GNU/Linux's Thread Local Storage (TLS)
3600 GDB now includes support for for the GNU/Linux implementation of
3601 per-thread variables.
3603 * GNU/Linux's Native POSIX Thread Library (NPTL)
3605 GDB's thread code has been updated to work with either the new
3606 GNU/Linux NPTL thread library or the older "LinuxThreads" library.
3608 * Separate debug info.
3610 GDB, in conjunction with BINUTILS, now supports a mechanism for
3611 automatically loading debug information from a separate file. Instead
3612 of shipping full debug and non-debug versions of system libraries,
3613 system integrators can now instead ship just the stripped libraries
3614 and optional debug files.
3616 * DWARF 2 Location Expressions
3618 DWARF 2 Location Expressions allow the compiler to more completely
3619 describe the location of variables (even in optimized code) to the
3622 GDB now includes preliminary support for location expressions (support
3623 for DW_OP_piece is still missing).
3627 A number of long standing bugs that caused GDB to die while starting a
3628 Java application have been fixed. GDB's Java support is now
3629 considered "useable".
3631 * GNU/Linux support for fork, vfork, and exec.
3633 The "catch fork", "catch exec", "catch vfork", and "set follow-fork-mode"
3634 commands are now implemented for GNU/Linux. They require a 2.5.x or later
3637 * GDB supports logging output to a file
3639 There are two new commands, "set logging" and "show logging", which can be
3640 used to capture GDB's output to a file.
3642 * The meaning of "detach" has changed for gdbserver
3644 The "detach" command will now resume the application, as documented. To
3645 disconnect from gdbserver and leave it stopped, use the new "disconnect"
3648 * d10v, m68hc11 `regs' command deprecated
3650 The `info registers' command has been updated so that it displays the
3651 registers using a format identical to the old `regs' command.
3655 A new command, "maint set profile on/off", has been added. This command can
3656 be used to enable or disable profiling while running GDB, to profile a
3657 session or a set of commands. In addition there is a new configure switch,
3658 "--enable-profiling", which will cause GDB to be compiled with profiling
3659 data, for more informative profiling results.
3661 * Default MI syntax changed to "mi2".
3663 The default MI (machine interface) syntax, enabled by the command line
3664 option "-i=mi", has been changed to "mi2". The previous MI syntax,
3665 "mi1", can be enabled by specifying the option "-i=mi1".
3667 Support for the original "mi0" syntax (included in GDB 5.0) has been
3670 Fix for gdb/192: removed extraneous space when displaying frame level.
3671 Fix for gdb/672: update changelist is now output in mi list format.
3672 Fix for gdb/702: a -var-assign that updates the value now shows up
3673 in a subsequent -var-update.
3675 * New native configurations.
3677 FreeBSD/amd64 x86_64-*-freebsd*
3679 * Multi-arched targets.
3681 HP/PA HPUX11 hppa*-*-hpux*
3682 Renesas M32R/D w/simulator m32r-*-elf*
3684 * OBSOLETE configurations and files
3686 Configurations that have been declared obsolete in this release have
3687 been commented out. Unless there is activity to revive these
3688 configurations, the next release of GDB will have their sources
3689 permanently REMOVED.
3691 Z8000 simulator z8k-zilog-none or z8ksim
3692 Matsushita MN10200 w/simulator mn10200-*-*
3693 H8/500 simulator h8500-hitachi-hms or h8500hms
3694 HP/PA running BSD hppa*-*-bsd*
3695 HP/PA running OSF/1 hppa*-*-osf*
3696 HP/PA Pro target hppa*-*-pro*
3697 PMAX (MIPS) running Mach 3.0 mips*-*-mach3*
3698 Sequent family i[3456]86-sequent-sysv4*
3699 i[3456]86-sequent-sysv*
3700 i[3456]86-sequent-bsd*
3701 Tsqware Sparclet sparclet-*-*
3702 Fujitsu SPARClite sparclite-fujitsu-none or sparclite
3704 * REMOVED configurations and files
3707 Motorola Delta 88000 running Sys V m88k-motorola-sysv or delta88
3708 IBM AIX PS/2 i[3456]86-*-aix
3709 i386 running Mach 3.0 i[3456]86-*-mach3*
3710 i386 running Mach i[3456]86-*-mach*
3711 i386 running OSF/1 i[3456]86-*osf1mk*
3712 HP/Apollo 68k Family m68*-apollo*-sysv*,
3714 m68*-hp-bsd*, m68*-hp-hpux*
3715 Argonaut Risc Chip (ARC) arc-*-*
3716 Mitsubishi D30V d30v-*-*
3717 Fujitsu FR30 fr30-*-elf*
3718 OS/9000 i[34]86-*-os9k
3719 I960 with MON960 i960-*-coff
3721 * MIPS $fp behavior changed
3723 The convenience variable $fp, for the MIPS, now consistently returns
3724 the address of the current frame's base. Previously, depending on the
3725 context, $fp could refer to either $sp or the current frame's base
3726 address. See ``8.10 Registers'' in the manual ``Debugging with GDB:
3727 The GNU Source-Level Debugger''.
3729 *** Changes in GDB 5.3:
3731 * GNU/Linux shared library multi-threaded performance improved.
3733 When debugging a multi-threaded application on GNU/Linux, GDB now uses
3734 `/proc', in preference to `ptrace' for memory reads. This may result
3735 in an improvement in the start-up time of multi-threaded, shared
3736 library applications when run under GDB. One GDB user writes: ``loads
3737 shared libs like mad''.
3739 * ``gdbserver'' now supports multi-threaded applications on some targets
3741 Support for debugging multi-threaded applications which use
3742 the GNU/Linux LinuxThreads package has been added for
3743 arm*-*-linux*-gnu*, i[3456]86-*-linux*-gnu*, mips*-*-linux*-gnu*,
3744 powerpc*-*-linux*-gnu*, and sh*-*-linux*-gnu*.
3746 * GDB now supports C/C++ preprocessor macros.
3748 GDB now expands preprocessor macro invocations in C/C++ expressions,
3749 and provides various commands for showing macro definitions and how
3752 The new command `macro expand EXPRESSION' expands any macro
3753 invocations in expression, and shows the result.
3755 The new command `show macro MACRO-NAME' shows the definition of the
3756 macro named MACRO-NAME, and where it was defined.
3758 Most compilers don't include information about macros in the debugging
3759 information by default. In GCC 3.1, for example, you need to compile
3760 your program with the options `-gdwarf-2 -g3'. If the macro
3761 information is present in the executable, GDB will read it.
3763 * Multi-arched targets.
3765 DEC Alpha (partial) alpha*-*-*
3766 DEC VAX (partial) vax-*-*
3768 National Semiconductor NS32000 (partial) ns32k-*-*
3769 Motorola 68000 (partial) m68k-*-*
3770 Motorola MCORE mcore-*-*
3774 Fujitsu FRV architecture added by Red Hat frv*-*-*
3777 * New native configurations
3779 Alpha NetBSD alpha*-*-netbsd*
3780 SH NetBSD sh*-*-netbsdelf*
3781 MIPS NetBSD mips*-*-netbsd*
3782 UltraSPARC NetBSD sparc64-*-netbsd*
3784 * OBSOLETE configurations and files
3786 Configurations that have been declared obsolete in this release have
3787 been commented out. Unless there is activity to revive these
3788 configurations, the next release of GDB will have their sources
3789 permanently REMOVED.
3791 Mitsubishi D30V d30v-*-*
3792 OS/9000 i[34]86-*-os9k
3793 IBM AIX PS/2 i[3456]86-*-aix
3794 Fujitsu FR30 fr30-*-elf*
3795 Motorola Delta 88000 running Sys V m88k-motorola-sysv or delta88
3796 Argonaut Risc Chip (ARC) arc-*-*
3797 i386 running Mach 3.0 i[3456]86-*-mach3*
3798 i386 running Mach i[3456]86-*-mach*
3799 i386 running OSF/1 i[3456]86-*osf1mk*
3800 HP/Apollo 68k Family m68*-apollo*-sysv*,
3802 m68*-hp-bsd*, m68*-hp-hpux*
3803 I960 with MON960 i960-*-coff
3805 * OBSOLETE languages
3807 CHILL, a Pascal like language used by telecommunications companies.
3809 * REMOVED configurations and files
3811 AMD 29k family via UDI a29k-amd-udi, udi29k
3812 A29K VxWorks a29k-*-vxworks
3813 AMD 29000 embedded, using EBMON a29k-none-none
3814 AMD 29000 embedded with COFF a29k-none-coff
3815 AMD 29000 embedded with a.out a29k-none-aout
3817 testsuite/gdb.hp/gdb.threads-hp/ directory
3819 * New command "set max-user-call-depth <nnn>"
3821 This command allows the user to limit the call depth of user-defined
3822 commands. The default is 1024.
3824 * Changes in FreeBSD/i386 native debugging.
3826 Support for the "generate-core-file" has been added.
3828 * New commands "dump", "append", and "restore".
3830 These commands allow data to be copied from target memory
3831 to a bfd-format or binary file (dump and append), and back
3832 from a file into memory (restore).
3834 * Improved "next/step" support on multi-processor Alpha Tru64.
3836 The previous single-step mechanism could cause unpredictable problems,
3837 including the random appearance of SIGSEGV or SIGTRAP signals. The use
3838 of a software single-step mechanism prevents this.
3840 *** Changes in GDB 5.2.1:
3848 gdb/182: gdb/323: gdb/237: On alpha, gdb was reporting:
3849 mdebugread.c:2443: gdb-internal-error: sect_index_data not initialized
3850 Fix, by Joel Brobecker imported from mainline.
3852 gdb/439: gdb/291: On some ELF object files, gdb was reporting:
3853 dwarf2read.c:1072: gdb-internal-error: sect_index_text not initialize
3854 Fix, by Fred Fish, imported from mainline.
3856 Dwarf2 .debug_frame & .eh_frame handler improved in many ways.
3857 Surprisingly enough, it works now.
3858 By Michal Ludvig, imported from mainline.
3860 i386 hardware watchpoint support:
3861 avoid misses on second run for some targets.
3862 By Pierre Muller, imported from mainline.
3864 *** Changes in GDB 5.2:
3866 * New command "set trust-readonly-sections on[off]".
3868 This command is a hint that tells gdb that read-only sections
3869 really are read-only (ie. that their contents will not change).
3870 In this mode, gdb will go to the object file rather than the
3871 target to read memory from read-only sections (such as ".text").
3872 This can be a significant performance improvement on some
3873 (notably embedded) targets.
3875 * New command "generate-core-file" (or "gcore").
3877 This new gdb command allows the user to drop a core file of the child
3878 process state at any time. So far it's been implemented only for
3879 GNU/Linux and Solaris, but should be relatively easily ported to other
3880 hosts. Argument is core file name (defaults to core.<pid>).
3882 * New command line option
3884 GDB now accepts --pid or -p followed by a process id.
3886 * Change in command line behavior -- corefiles vs. process ids.
3888 There is a subtle behavior in the way in which GDB handles
3889 command line arguments. The first non-flag argument is always
3890 a program to debug, but the second non-flag argument may either
3891 be a corefile or a process id. Previously, GDB would attempt to
3892 open the second argument as a corefile, and if that failed, would
3893 issue a superfluous error message and then attempt to attach it as
3894 a process. Now, if the second argument begins with a non-digit,
3895 it will be treated as a corefile. If it begins with a digit,
3896 GDB will attempt to attach it as a process, and if no such process
3897 is found, will then attempt to open it as a corefile.
3899 * Changes in ARM configurations.
3901 Multi-arch support is enabled for all ARM configurations. The ARM/NetBSD
3902 configuration is fully multi-arch.
3904 * New native configurations
3906 ARM NetBSD arm*-*-netbsd*
3907 x86 OpenBSD i[3456]86-*-openbsd*
3908 AMD x86-64 running GNU/Linux x86_64-*-linux-*
3909 Sparc64 running FreeBSD sparc64-*-freebsd*
3913 Sanyo XStormy16 xstormy16-elf
3915 * OBSOLETE configurations and files
3917 Configurations that have been declared obsolete in this release have
3918 been commented out. Unless there is activity to revive these
3919 configurations, the next release of GDB will have their sources
3920 permanently REMOVED.
3922 AMD 29k family via UDI a29k-amd-udi, udi29k
3923 A29K VxWorks a29k-*-vxworks
3924 AMD 29000 embedded, using EBMON a29k-none-none
3925 AMD 29000 embedded with COFF a29k-none-coff
3926 AMD 29000 embedded with a.out a29k-none-aout
3928 testsuite/gdb.hp/gdb.threads-hp/ directory
3930 * REMOVED configurations and files
3932 TI TMS320C80 tic80-*-*
3934 PowerPC Solaris powerpcle-*-solaris*
3935 PowerPC Windows NT powerpcle-*-cygwin32
3936 PowerPC Netware powerpc-*-netware*
3937 Harris/CXUX m88k m88*-harris-cxux*
3938 Most ns32k hosts and targets ns32k-*-mach3* ns32k-umax-*
3939 ns32k-utek-sysv* ns32k-utek-*
3940 SunOS 4.0.Xi on i386 i[3456]86-*-sunos*
3941 Ultracomputer (29K) running Sym1 a29k-nyu-sym1 a29k-*-kern*
3942 Sony NEWS (68K) running NEWSOS 3.x m68*-sony-sysv news
3943 ISI Optimum V (3.05) under 4.3bsd. m68*-isi-*
3944 Apple Macintosh (MPW) host and target N/A host, powerpc-*-macos*
3946 * Changes to command line processing
3948 The new `--args' feature can be used to specify command-line arguments
3949 for the inferior from gdb's command line.
3951 * Changes to key bindings
3953 There is a new `operate-and-get-next' function bound to `C-o'.
3955 *** Changes in GDB 5.1.1
3957 Fix compile problem on DJGPP.
3959 Fix a problem with floating-point registers on the i386 being
3962 Fix to stop GDB crashing on .debug_str debug info.
3964 Numerous documentation fixes.
3966 Numerous testsuite fixes.
3968 *** Changes in GDB 5.1:
3970 * New native configurations
3972 Alpha FreeBSD alpha*-*-freebsd*
3973 x86 FreeBSD 3.x and 4.x i[3456]86*-freebsd[34]*
3974 MIPS GNU/Linux mips*-*-linux*
3975 MIPS SGI Irix 6.x mips*-sgi-irix6*
3976 ia64 AIX ia64-*-aix*
3977 s390 and s390x GNU/Linux {s390,s390x}-*-linux*
3981 Motorola 68HC11 and 68HC12 m68hc11-elf
3983 UltraSparc running GNU/Linux sparc64-*-linux*
3985 * OBSOLETE configurations and files
3987 x86 FreeBSD before 2.2 i[3456]86*-freebsd{1,2.[01]}*,
3988 Harris/CXUX m88k m88*-harris-cxux*
3989 Most ns32k hosts and targets ns32k-*-mach3* ns32k-umax-*
3990 ns32k-utek-sysv* ns32k-utek-*
3991 TI TMS320C80 tic80-*-*
3993 Ultracomputer (29K) running Sym1 a29k-nyu-sym1 a29k-*-kern*
3994 PowerPC Solaris powerpcle-*-solaris*
3995 PowerPC Windows NT powerpcle-*-cygwin32
3996 PowerPC Netware powerpc-*-netware*
3997 SunOS 4.0.Xi on i386 i[3456]86-*-sunos*
3998 Sony NEWS (68K) running NEWSOS 3.x m68*-sony-sysv news
3999 ISI Optimum V (3.05) under 4.3bsd. m68*-isi-*
4000 Apple Macintosh (MPW) host N/A
4002 stuff.c (Program to stuff files into a specially prepared space in kdb)
4003 kdb-start.c (Main loop for the standalone kernel debugger)
4005 Configurations that have been declared obsolete in this release have
4006 been commented out. Unless there is activity to revive these
4007 configurations, the next release of GDB will have their sources
4008 permanently REMOVED.
4010 * REMOVED configurations and files
4012 Altos 3068 m68*-altos-*
4013 Convex c1-*-*, c2-*-*
4015 ARM RISCix arm-*-* (as host)
4019 * GDB has been converted to ISO C.
4021 GDB's source code has been converted to ISO C. In particular, the
4022 sources are fully protoized, and rely on standard headers being
4027 * "info symbol" works on platforms which use COFF, ECOFF, XCOFF, and NLM.
4029 * The MI enabled by default.
4031 The new machine oriented interface (MI) introduced in GDB 5.0 has been
4032 revised and enabled by default. Packages which use GDB as a debugging
4033 engine behind a UI or another front end are encouraged to switch to
4034 using the GDB/MI interface, instead of the old annotations interface
4035 which is now deprecated.
4037 * Support for debugging Pascal programs.
4039 GDB now includes support for debugging Pascal programs. The following
4040 main features are supported:
4042 - Pascal-specific data types such as sets;
4044 - automatic recognition of Pascal sources based on file-name
4047 - Pascal-style display of data types, variables, and functions;
4049 - a Pascal expression parser.
4051 However, some important features are not yet supported.
4053 - Pascal string operations are not supported at all;
4055 - there are some problems with boolean types;
4057 - Pascal type hexadecimal constants are not supported
4058 because they conflict with the internal variables format;
4060 - support for Pascal objects and classes is not full yet;
4062 - unlike Pascal, GDB is case-sensitive for symbol names.
4064 * Changes in completion.
4066 Commands such as `shell', `run' and `set args', which pass arguments
4067 to inferior programs, now complete on file names, similar to what
4068 users expect at the shell prompt.
4070 Commands which accept locations, such as `disassemble', `print',
4071 `breakpoint', `until', etc. now complete on filenames as well as
4072 program symbols. Thus, if you type "break foob TAB", and the source
4073 files linked into the programs include `foobar.c', that file name will
4074 be one of the candidates for completion. However, file names are not
4075 considered for completion after you typed a colon that delimits a file
4076 name from a name of a function in that file, as in "break foo.c:bar".
4078 `set demangle-style' completes on available demangling styles.
4080 * New platform-independent commands:
4082 It is now possible to define a post-hook for a command as well as a
4083 hook that runs before the command. For more details, see the
4084 documentation of `hookpost' in the GDB manual.
4086 * Changes in GNU/Linux native debugging.
4088 Support for debugging multi-threaded programs has been completely
4089 revised for all platforms except m68k and sparc. You can now debug as
4090 many threads as your system allows you to have.
4092 Attach/detach is supported for multi-threaded programs.
4094 Support for SSE registers was added for x86. This doesn't work for
4095 multi-threaded programs though.
4097 * Changes in MIPS configurations.
4099 Multi-arch support is enabled for all MIPS configurations.
4101 GDB can now be built as native debugger on SGI Irix 6.x systems for
4102 debugging n32 executables. (Debugging 64-bit executables is not yet
4105 * Unified support for hardware watchpoints in all x86 configurations.
4107 Most (if not all) native x86 configurations support hardware-assisted
4108 breakpoints and watchpoints in a unified manner. This support
4109 implements debug register sharing between watchpoints, which allows to
4110 put a virtually infinite number of watchpoints on the same address,
4111 and also supports watching regions up to 16 bytes with several debug
4114 The new maintenance command `maintenance show-debug-regs' toggles
4115 debugging print-outs in functions that insert, remove, and test
4116 watchpoints and hardware breakpoints.
4118 * Changes in the DJGPP native configuration.
4120 New command ``info dos sysinfo'' displays assorted information about
4121 the CPU, OS, memory, and DPMI server.
4123 New commands ``info dos gdt'', ``info dos ldt'', and ``info dos idt''
4124 display information about segment descriptors stored in GDT, LDT, and
4127 New commands ``info dos pde'' and ``info dos pte'' display entries
4128 from Page Directory and Page Tables (for now works with CWSDPMI only).
4129 New command ``info dos address-pte'' displays the Page Table entry for
4130 a given linear address.
4132 GDB can now pass command lines longer than 126 characters to the
4133 program being debugged (requires an update to the libdbg.a library
4134 which is part of the DJGPP development kit).
4136 DWARF2 debug info is now supported.
4138 It is now possible to `step' and `next' through calls to `longjmp'.
4140 * Changes in documentation.
4142 All GDB documentation was converted to GFDL, the GNU Free
4143 Documentation License.
4145 Tracepoints-related commands are now fully documented in the GDB
4148 TUI, the Text-mode User Interface, is now documented in the manual.
4150 Tracepoints-related commands are now fully documented in the GDB
4153 The "GDB Internals" manual now has an index. It also includes
4154 documentation of `ui_out' functions, GDB coding standards, x86
4155 hardware watchpoints, and memory region attributes.
4157 * GDB's version number moved to ``version.in''
4159 The Makefile variable VERSION has been replaced by the file
4160 ``version.in''. People creating GDB distributions should update the
4161 contents of this file.
4165 GUD support is now a standard part of the EMACS distribution.
4167 *** Changes in GDB 5.0:
4169 * Improved support for debugging FP programs on x86 targets
4171 Unified and much-improved support for debugging floating-point
4172 programs on all x86 targets. In particular, ``info float'' now
4173 displays the FP registers in the same format on all x86 targets, with
4174 greater level of detail.
4176 * Improvements and bugfixes in hardware-assisted watchpoints
4178 It is now possible to watch array elements, struct members, and
4179 bitfields with hardware-assisted watchpoints. Data-read watchpoints
4180 on x86 targets no longer erroneously trigger when the address is
4183 * Improvements in the native DJGPP version of GDB
4185 The distribution now includes all the scripts and auxiliary files
4186 necessary to build the native DJGPP version on MS-DOS/MS-Windows
4187 machines ``out of the box''.
4189 The DJGPP version can now debug programs that use signals. It is
4190 possible to catch signals that happened in the debuggee, deliver
4191 signals to it, interrupt it with Ctrl-C, etc. (Previously, a signal
4192 would kill the program being debugged.) Programs that hook hardware
4193 interrupts (keyboard, timer, etc.) can also be debugged.
4195 It is now possible to debug DJGPP programs that redirect their
4196 standard handles or switch them to raw (as opposed to cooked) mode, or
4197 even close them. The command ``run < foo > bar'' works as expected,
4198 and ``info terminal'' reports useful information about the debuggee's
4199 terminal, including raw/cooked mode, redirection, etc.
4201 The DJGPP version now uses termios functions for console I/O, which
4202 enables debugging graphics programs. Interrupting GDB with Ctrl-C
4205 DOS-style file names with drive letters are now fully supported by
4208 It is now possible to debug DJGPP programs that switch their working
4209 directory. It is also possible to rerun the debuggee any number of
4210 times without restarting GDB; thus, you can use the same setup,
4211 breakpoints, etc. for many debugging sessions.
4213 * New native configurations
4215 ARM GNU/Linux arm*-*-linux*
4216 PowerPC GNU/Linux powerpc-*-linux*
4220 Motorola MCore mcore-*-*
4221 x86 VxWorks i[3456]86-*-vxworks*
4222 PowerPC VxWorks powerpc-*-vxworks*
4223 TI TMS320C80 tic80-*-*
4225 * OBSOLETE configurations
4227 Altos 3068 m68*-altos-*
4228 Convex c1-*-*, c2-*-*
4230 ARM RISCix arm-*-* (as host)
4233 Configurations that have been declared obsolete will be commented out,
4234 but the code will be left in place. If there is no activity to revive
4235 these configurations before the next release of GDB, the sources will
4236 be permanently REMOVED.
4238 * Gould support removed
4240 Support for the Gould PowerNode and NP1 has been removed.
4242 * New features for SVR4
4244 On SVR4 native platforms (such as Solaris), if you attach to a process
4245 without first loading a symbol file, GDB will now attempt to locate and
4246 load symbols from the running process's executable file.
4248 * Many C++ enhancements
4250 C++ support has been greatly improved. Overload resolution now works properly
4251 in almost all cases. RTTI support is on the way.
4253 * Remote targets can connect to a sub-program
4255 A popen(3) style serial-device has been added. This device starts a
4256 sub-process (such as a stand-alone simulator) and then communicates
4257 with that. The sub-program to run is specified using the syntax
4258 ``|<program> <args>'' vis:
4260 (gdb) set remotedebug 1
4261 (gdb) target extended-remote |mn10300-elf-sim program-args
4263 * MIPS 64 remote protocol
4265 A long standing bug in the mips64 remote protocol where by GDB
4266 expected certain 32 bit registers (ex SR) to be transfered as 32
4267 instead of 64 bits has been fixed.
4269 The command ``set remote-mips64-transfers-32bit-regs on'' has been
4270 added to provide backward compatibility with older versions of GDB.
4272 * ``set remotebinarydownload'' replaced by ``set remote X-packet''
4274 The command ``set remotebinarydownload'' command has been replaced by
4275 ``set remote X-packet''. Other commands in ``set remote'' family
4276 include ``set remote P-packet''.
4278 * Breakpoint commands accept ranges.
4280 The breakpoint commands ``enable'', ``disable'', and ``delete'' now
4281 accept a range of breakpoints, e.g. ``5-7''. The tracepoint command
4282 ``tracepoint passcount'' also accepts a range of tracepoints.
4284 * ``apropos'' command added.
4286 The ``apropos'' command searches through command names and
4287 documentation strings, printing out matches, making it much easier to
4288 try to find a command that does what you are looking for.
4292 A new machine oriented interface (MI) has been added to GDB. This
4293 interface is designed for debug environments running GDB as a separate
4294 process. This is part of the long term libGDB project. See the
4295 "GDB/MI" chapter of the GDB manual for further information. It can be
4296 enabled by configuring with:
4298 .../configure --enable-gdbmi
4300 *** Changes in GDB-4.18:
4302 * New native configurations
4304 HP-UX 10.20 hppa*-*-hpux10.20
4305 HP-UX 11.x hppa*-*-hpux11.0*
4306 M68K GNU/Linux m68*-*-linux*
4310 Fujitsu FR30 fr30-*-elf*
4311 Intel StrongARM strongarm-*-*
4312 Mitsubishi D30V d30v-*-*
4314 * OBSOLETE configurations
4316 Gould PowerNode, NP1 np1-*-*, pn-*-*
4318 Configurations that have been declared obsolete will be commented out,
4319 but the code will be left in place. If there is no activity to revive
4320 these configurations before the next release of GDB, the sources will
4321 be permanently REMOVED.
4325 As a compatibility experiment, GDB's source files buildsym.h and
4326 buildsym.c have been converted to pure standard C, no longer
4327 containing any K&R compatibility code. We believe that all systems in
4328 use today either come with a standard C compiler, or have a GCC port
4329 available. If this is not true, please report the affected
4330 configuration to bug-gdb@gnu.org immediately. See the README file for
4331 information about getting a standard C compiler if you don't have one
4336 GDB now uses readline 2.2.
4338 * set extension-language
4340 You can now control the mapping between filename extensions and source
4341 languages by using the `set extension-language' command. For instance,
4342 you can ask GDB to treat .c files as C++ by saying
4343 set extension-language .c c++
4344 The command `info extensions' lists all of the recognized extensions
4345 and their associated languages.
4347 * Setting processor type for PowerPC and RS/6000
4349 When GDB is configured for a powerpc*-*-* or an rs6000*-*-* target,
4350 you can use the `set processor' command to specify what variant of the
4351 PowerPC family you are debugging. The command
4355 sets the PowerPC/RS6000 variant to NAME. GDB knows about the
4356 following PowerPC and RS6000 variants:
4358 ppc-uisa PowerPC UISA - a PPC processor as viewed by user-level code
4359 rs6000 IBM RS6000 ("POWER") architecture, user-level view
4361 403GC IBM PowerPC 403GC
4362 505 Motorola PowerPC 505
4363 860 Motorola PowerPC 860 or 850
4364 601 Motorola PowerPC 601
4365 602 Motorola PowerPC 602
4366 603 Motorola/IBM PowerPC 603 or 603e
4367 604 Motorola PowerPC 604 or 604e
4368 750 Motorola/IBM PowerPC 750 or 750
4370 At the moment, this command just tells GDB what to name the
4371 special-purpose processor registers. Since almost all the affected
4372 registers are inaccessible to user-level programs, this command is
4373 only useful for remote debugging in its present form.
4377 Thanks to a major code donation from Hewlett-Packard, GDB now has much
4378 more extensive support for HP-UX. Added features include shared
4379 library support, kernel threads and hardware watchpoints for 11.00,
4380 support for HP's ANSI C and C++ compilers, and a compatibility mode
4381 for xdb and dbx commands.
4385 HP's donation includes the new concept of catchpoints, which is a
4386 generalization of the old catch command. On HP-UX, it is now possible
4387 to catch exec, fork, and vfork, as well as library loading.
4389 This means that the existing catch command has changed; its first
4390 argument now specifies the type of catch to be set up. See the
4391 output of "help catch" for a list of catchpoint types.
4393 * Debugging across forks
4395 On HP-UX, you can choose which process to debug when a fork() happens
4400 HP has donated a curses-based terminal user interface (TUI). To get
4401 it, build with --enable-tui. Although this can be enabled for any
4402 configuration, at present it only works for native HP debugging.
4404 * GDB remote protocol additions
4406 A new protocol packet 'X' that writes binary data is now available.
4407 Default behavior is to try 'X', then drop back to 'M' if the stub
4408 fails to respond. The settable variable `remotebinarydownload'
4409 allows explicit control over the use of 'X'.
4411 For 64-bit targets, the memory packets ('M' and 'm') can now contain a
4412 full 64-bit address. The command
4414 set remoteaddresssize 32
4416 can be used to revert to the old behaviour. For existing remote stubs
4417 the change should not be noticed, as the additional address information
4420 In order to assist in debugging stubs, you may use the maintenance
4421 command `packet' to send any text string to the stub. For instance,
4423 maint packet heythere
4425 sends the packet "$heythere#<checksum>". Note that it is very easy to
4426 disrupt a debugging session by sending the wrong packet at the wrong
4429 The compare-sections command allows you to compare section data on the
4430 target to what is in the executable file without uploading or
4431 downloading, by comparing CRC checksums.
4433 * Tracing can collect general expressions
4435 You may now collect general expressions at tracepoints. This requires
4436 further additions to the target-side stub; see tracepoint.c and
4437 doc/agentexpr.texi for further details.
4439 * mask-address variable for Mips
4441 For Mips targets, you may control the zeroing of the upper 32 bits of
4442 a 64-bit address by entering `set mask-address on'. This is mainly
4443 of interest to users of embedded R4xxx and R5xxx processors.
4445 * Higher serial baud rates
4447 GDB's serial code now allows you to specify baud rates 57600, 115200,
4448 230400, and 460800 baud. (Note that your host system may not be able
4449 to achieve all of these rates.)
4453 The i960 configuration now includes an initial implementation of a
4454 builtin simulator, contributed by Jim Wilson.
4457 *** Changes in GDB-4.17:
4459 * New native configurations
4461 Alpha GNU/Linux alpha*-*-linux*
4462 Unixware 2.x i[3456]86-unixware2*
4463 Irix 6.x mips*-sgi-irix6*
4464 PowerPC GNU/Linux powerpc-*-linux*
4465 PowerPC Solaris powerpcle-*-solaris*
4466 Sparc GNU/Linux sparc-*-linux*
4467 Motorola sysV68 R3V7.1 m68k-motorola-sysv
4471 Argonaut Risc Chip (ARC) arc-*-*
4472 Hitachi H8/300S h8300*-*-*
4473 Matsushita MN10200 w/simulator mn10200-*-*
4474 Matsushita MN10300 w/simulator mn10300-*-*
4475 MIPS NEC VR4100 mips64*vr4100*{,el}-*-elf*
4476 MIPS NEC VR5000 mips64*vr5000*{,el}-*-elf*
4477 MIPS Toshiba TX39 mips64*tx39*{,el}-*-elf*
4478 Mitsubishi D10V w/simulator d10v-*-*
4479 Mitsubishi M32R/D w/simulator m32r-*-elf*
4480 Tsqware Sparclet sparclet-*-*
4481 NEC V850 w/simulator v850-*-*
4483 * New debugging protocols
4485 ARM with RDI protocol arm*-*-*
4486 M68K with dBUG monitor m68*-*-{aout,coff,elf}
4487 DDB and LSI variants of PMON protocol mips*-*-*
4488 PowerPC with DINK32 monitor powerpc{,le}-*-eabi
4489 PowerPC with SDS protocol powerpc{,le}-*-eabi
4490 Macraigor OCD (Wiggler) devices powerpc{,le}-*-eabi
4494 All configurations can now understand and use the DWARF 2 debugging
4495 format. The choice is automatic, if the symbol file contains DWARF 2
4500 GDB now includes basic Java language support. This support is
4501 only useful with Java compilers that produce native machine code.
4503 * solib-absolute-prefix and solib-search-path
4505 For SunOS and SVR4 shared libraries, you may now set the prefix for
4506 loading absolute shared library symbol files, and the search path for
4507 locating non-absolute shared library symbol files.
4509 * Live range splitting
4511 GDB can now effectively debug code for which GCC has performed live
4512 range splitting as part of its optimization. See gdb/doc/LRS for
4513 more details on the expected format of the stabs information.
4517 GDB's support for the GNU Hurd, including thread debugging, has been
4518 updated to work with current versions of the Hurd.
4522 GDB's ARM target configuration now handles the ARM7T (Thumb) 16-bit
4523 instruction set. ARM GDB automatically detects when Thumb
4524 instructions are in use, and adjusts disassembly and backtracing
4529 GDB's MIPS target configurations now handle the MIP16 16-bit
4534 GDB now includes support for overlays; if an executable has been
4535 linked such that multiple sections are based at the same address, GDB
4536 will decide which section to use for symbolic info. You can choose to
4537 control the decision manually, using overlay commands, or implement
4538 additional target-side support and use "overlay load-target" to bring
4539 in the overlay mapping. Do "help overlay" for more detail.
4543 The command "info symbol <address>" displays information about
4544 the symbol at the specified address.
4548 The standard remote protocol now includes an extension that allows
4549 asynchronous collection and display of trace data. This requires
4550 extensive support in the target-side debugging stub. Tracing mode
4551 includes a new interaction mode in GDB and new commands: see the
4552 file tracepoint.c for more details.
4556 Configurations for embedded MIPS now include a simulator contributed
4557 by Cygnus Solutions. The simulator supports the instruction sets
4558 of most MIPS variants.
4562 Sparc configurations may now include the ERC32 simulator contributed
4563 by the European Space Agency. The simulator is not built into
4564 Sparc targets by default; configure with --enable-sim to include it.
4568 For target configurations that may include multiple variants of a
4569 basic architecture (such as MIPS and SH), you may now set the
4570 architecture explicitly. "set arch" sets, "info arch" lists
4571 the possible architectures.
4573 *** Changes in GDB-4.16:
4575 * New native configurations
4577 Windows 95, x86 Windows NT i[345]86-*-cygwin32
4578 M68K NetBSD m68k-*-netbsd*
4579 PowerPC AIX 4.x powerpc-*-aix*
4580 PowerPC MacOS powerpc-*-macos*
4581 PowerPC Windows NT powerpcle-*-cygwin32
4582 RS/6000 AIX 4.x rs6000-*-aix4*
4586 ARM with RDP protocol arm-*-*
4587 I960 with MON960 i960-*-coff
4588 MIPS VxWorks mips*-*-vxworks*
4589 MIPS VR4300 with PMON mips64*vr4300{,el}-*-elf*
4590 PowerPC with PPCBUG monitor powerpc{,le}-*-eabi*
4592 Matra Sparclet sparclet-*-*
4596 The powerpc-eabi configuration now includes the PSIM simulator,
4597 contributed by Andrew Cagney, with assistance from Mike Meissner.
4598 PSIM is a very elaborate model of the PowerPC, including not only
4599 basic instruction set execution, but also details of execution unit
4600 performance and I/O hardware. See sim/ppc/README for more details.
4604 GDB now works with Solaris 2.5.
4606 * Windows 95/NT native
4608 GDB will now work as a native debugger on Windows 95 and Windows NT.
4609 To build it from source, you must use the "gnu-win32" environment,
4610 which uses a DLL to emulate enough of Unix to run the GNU tools.
4611 Further information, binaries, and sources are available at
4612 ftp.cygnus.com, under pub/gnu-win32.
4614 * dont-repeat command
4616 If a user-defined command includes the command `dont-repeat', then the
4617 command will not be repeated if the user just types return. This is
4618 useful if the command is time-consuming to run, so that accidental
4619 extra keystrokes don't run the same command many times.
4621 * Send break instead of ^C
4623 The standard remote protocol now includes an option to send a break
4624 rather than a ^C to the target in order to interrupt it. By default,
4625 GDB will send ^C; to send a break, set the variable `remotebreak' to 1.
4627 * Remote protocol timeout
4629 The standard remote protocol includes a new variable `remotetimeout'
4630 that allows you to set the number of seconds before GDB gives up trying
4631 to read from the target. The default value is 2.
4633 * Automatic tracking of dynamic object loading (HPUX and Solaris only)
4635 By default GDB will automatically keep track of objects as they are
4636 loaded and unloaded by the dynamic linker. By using the command `set
4637 stop-on-solib-events 1' you can arrange for GDB to stop the inferior
4638 when shared library events occur, thus allowing you to set breakpoints
4639 in shared libraries which are explicitly loaded by the inferior.
4641 Note this feature does not work on hpux8. On hpux9 you must link
4642 /usr/lib/end.o into your program. This feature should work
4643 automatically on hpux10.
4645 * Irix 5.x hardware watchpoint support
4647 Irix 5 configurations now support the use of hardware watchpoints.
4649 * Mips protocol "SYN garbage limit"
4651 When debugging a Mips target using the `target mips' protocol, you
4652 may set the number of characters that GDB will ignore by setting
4653 the `syn-garbage-limit'. A value of -1 means that GDB will ignore
4654 every character. The default value is 1050.
4656 * Recording and replaying remote debug sessions
4658 If you set `remotelogfile' to the name of a file, gdb will write to it
4659 a recording of a remote debug session. This recording may then be
4660 replayed back to gdb using "gdbreplay". See gdbserver/README for
4661 details. This is useful when you have a problem with GDB while doing
4662 remote debugging; you can make a recording of the session and send it
4663 to someone else, who can then recreate the problem.
4665 * Speedups for remote debugging
4667 GDB includes speedups for downloading and stepping MIPS systems using
4668 the IDT monitor, fast downloads to the Hitachi SH E7000 emulator,
4669 and more efficient S-record downloading.
4671 * Memory use reductions and statistics collection
4673 GDB now uses less memory and reports statistics about memory usage.
4674 Try the `maint print statistics' command, for example.
4676 *** Changes in GDB-4.15:
4678 * Psymtabs for XCOFF
4680 The symbol reader for AIX GDB now uses partial symbol tables. This
4681 can greatly improve startup time, especially for large executables.
4683 * Remote targets use caching
4685 Remote targets now use a data cache to speed up communication with the
4686 remote side. The data cache could lead to incorrect results because
4687 it doesn't know about volatile variables, thus making it impossible to
4688 debug targets which use memory mapped I/O devices. `set remotecache
4689 off' turns the the data cache off.
4691 * Remote targets may have threads
4693 The standard remote protocol now includes support for multiple threads
4694 in the target system, using new protocol commands 'H' and 'T'. See
4695 gdb/remote.c for details.
4699 If GDB is configured with `--enable-netrom', then it will include
4700 support for the NetROM ROM emulator from XLNT Designs. The NetROM
4701 acts as though it is a bank of ROM on the target board, but you can
4702 write into it over the network. GDB's support consists only of
4703 support for fast loading into the emulated ROM; to debug, you must use
4704 another protocol, such as standard remote protocol. The usual
4705 sequence is something like
4707 target nrom <netrom-hostname>
4709 target remote <netrom-hostname>:1235
4713 GDB now includes support for the Apple Macintosh, as a host only. It
4714 may be run as either an MPW tool or as a standalone application, and
4715 it can debug through the serial port. All the usual GDB commands are
4716 available, but to the target command, you must supply "serial" as the
4717 device type instead of "/dev/ttyXX". See mpw-README in the main
4718 directory for more information on how to build. The MPW configuration
4719 scripts */mpw-config.in support only a few targets, and only the
4720 mips-idt-ecoff target has been tested.
4724 GDB configuration now uses autoconf. This is not user-visible,
4725 but does simplify configuration and building.
4729 GDB now supports hpux10.
4731 *** Changes in GDB-4.14:
4733 * New native configurations
4735 x86 FreeBSD i[345]86-*-freebsd
4736 x86 NetBSD i[345]86-*-netbsd
4737 NS32k NetBSD ns32k-*-netbsd
4738 Sparc NetBSD sparc-*-netbsd
4742 A29K VxWorks a29k-*-vxworks
4743 HP PA PRO embedded (WinBond W89K & Oki OP50N) hppa*-*-pro*
4744 CPU32 EST-300 emulator m68*-*-est*
4745 PowerPC ELF powerpc-*-elf
4748 * Alpha OSF/1 support for procfs
4750 GDB now supports procfs under OSF/1-2.x and higher, which makes it
4751 possible to attach to running processes. As the mounting of the /proc
4752 filesystem is optional on the Alpha, GDB automatically determines
4753 the availability of /proc during startup. This can lead to problems
4754 if /proc is unmounted after GDB has been started.
4756 * Arguments to user-defined commands
4758 User commands may accept up to 10 arguments separated by whitespace.
4759 Arguments are accessed within the user command via $arg0..$arg9. A
4762 print $arg0 + $arg1 + $arg2
4764 To execute the command use:
4767 Defines the command "adder" which prints the sum of its three arguments.
4768 Note the arguments are text substitutions, so they may reference variables,
4769 use complex expressions, or even perform inferior function calls.
4771 * New `if' and `while' commands
4773 This makes it possible to write more sophisticated user-defined
4774 commands. Both commands take a single argument, which is the
4775 expression to evaluate, and must be followed by the commands to
4776 execute, one per line, if the expression is nonzero, the list being
4777 terminated by the word `end'. The `if' command list may include an
4778 `else' word, which causes the following commands to be executed only
4779 if the expression is zero.
4781 * Fortran source language mode
4783 GDB now includes partial support for Fortran 77. It will recognize
4784 Fortran programs and can evaluate a subset of Fortran expressions, but
4785 variables and functions may not be handled correctly. GDB will work
4786 with G77, but does not yet know much about symbols emitted by other
4789 * Better HPUX support
4791 Most debugging facilities now work on dynamic executables for HPPAs
4792 running hpux9 or later. You can attach to running dynamically linked
4793 processes, but by default the dynamic libraries will be read-only, so
4794 for instance you won't be able to put breakpoints in them. To change
4795 that behavior do the following before running the program:
4801 This will cause the libraries to be mapped private and read-write.
4802 To revert to the normal behavior, do this:
4808 You cannot set breakpoints or examine data in the library until after
4809 the library is loaded if the function/data symbols do not have
4812 GDB can now also read debug symbols produced by the HP C compiler on
4813 HPPAs (sorry, no C++, Fortran or 68k support).
4815 * Target byte order now dynamically selectable
4817 You can choose which byte order to use with a target system, via the
4818 commands "set endian big" and "set endian little", and you can see the
4819 current setting by using "show endian". You can also give the command
4820 "set endian auto", in which case GDB will use the byte order
4821 associated with the executable. Currently, only embedded MIPS
4822 configurations support dynamic selection of target byte order.
4824 * New DOS host serial code
4826 This version uses DPMI interrupts to handle buffered I/O, so you
4827 no longer need to run asynctsr when debugging boards connected to
4830 *** Changes in GDB-4.13:
4832 * New "complete" command
4834 This lists all the possible completions for the rest of the line, if it
4835 were to be given as a command itself. This is intended for use by emacs.
4837 * Trailing space optional in prompt
4839 "set prompt" no longer adds a space for you after the prompt you set. This
4840 allows you to set a prompt which ends in a space or one that does not.
4842 * Breakpoint hit counts
4844 "info break" now displays a count of the number of times the breakpoint
4845 has been hit. This is especially useful in conjunction with "ignore"; you
4846 can ignore a large number of breakpoint hits, look at the breakpoint info
4847 to see how many times the breakpoint was hit, then run again, ignoring one
4848 less than that number, and this will get you quickly to the last hit of
4851 * Ability to stop printing at NULL character
4853 "set print null-stop" will cause GDB to stop printing the characters of
4854 an array when the first NULL is encountered. This is useful when large
4855 arrays actually contain only short strings.
4857 * Shared library breakpoints
4859 In SunOS 4.x, SVR4, and Alpha OSF/1 configurations, you can now set
4860 breakpoints in shared libraries before the executable is run.
4862 * Hardware watchpoints
4864 There is a new hardware breakpoint for the watch command for sparclite
4865 targets. See gdb/sparclite/hw_breakpoint.note.
4867 Hardware watchpoints are also now supported under GNU/Linux.
4871 Annotations have been added. These are for use with graphical interfaces,
4872 and are still experimental. Currently only gdba.el uses these.
4874 * Improved Irix 5 support
4876 GDB now works properly with Irix 5.2.
4878 * Improved HPPA support
4880 GDB now works properly with the latest GCC and GAS.
4882 * New native configurations
4884 Sequent PTX4 i[34]86-sequent-ptx4
4885 HPPA running OSF/1 hppa*-*-osf*
4886 Atari TT running SVR4 m68*-*-sysv4*
4887 RS/6000 LynxOS rs6000-*-lynxos*
4891 OS/9000 i[34]86-*-os9k
4892 MIPS R4000 mips64*{,el}-*-{ecoff,elf}
4895 * Hitachi SH7000 and E7000-PC ICE support
4897 There is now support for communicating with the Hitachi E7000-PC ICE.
4898 This is available automatically when GDB is configured for the SH.
4902 As usual, a variety of small fixes and improvements, both generic
4903 and configuration-specific. See the ChangeLog for more detail.
4905 *** Changes in GDB-4.12:
4907 * Irix 5 is now supported
4911 GDB-4.12 on the HPPA has a number of changes which make it unable
4912 to debug the output from the currently released versions of GCC and
4913 GAS (GCC 2.5.8 and GAS-2.2 or PAGAS-1.36). Until the next major release
4914 of GCC and GAS, versions of these tools designed to work with GDB-4.12
4915 can be retrieved via anonymous ftp from jaguar.cs.utah.edu:/dist.
4918 *** Changes in GDB-4.11:
4920 * User visible changes:
4924 The "set remotedebug" option is now consistent between the mips remote
4925 target, remote targets using the gdb-specific protocol, UDI (AMD's
4926 debug protocol for the 29k) and the 88k bug monitor. It is now an
4927 integer specifying a debug level (normally 0 or 1, but 2 means more
4928 debugging info for the mips target).
4930 * DEC Alpha native support
4932 GDB now works on the DEC Alpha. GCC 2.4.5 does not produce usable
4933 debug info, but GDB works fairly well with the DEC compiler and should
4934 work with a future GCC release. See the README file for a few
4935 Alpha-specific notes.
4937 * Preliminary thread implementation
4939 GDB now has preliminary thread support for both SGI/Irix and LynxOS.
4941 * LynxOS native and target support for 386
4943 This release has been hosted on LynxOS 2.2, and also can be configured
4944 to remotely debug programs running under LynxOS (see gdb/gdbserver/README
4947 * Improvements in C++ mangling/demangling.
4949 This release has much better g++ debugging, specifically in name
4950 mangling/demangling, virtual function calls, print virtual table,
4951 call methods, ...etc.
4953 *** Changes in GDB-4.10:
4955 * User visible changes:
4957 Remote debugging using the GDB-specific (`target remote') protocol now
4958 supports the `load' command. This is only useful if you have some
4959 other way of getting the stub to the target system, and you can put it
4960 somewhere in memory where it won't get clobbered by the download.
4962 Filename completion now works.
4964 When run under emacs mode, the "info line" command now causes the
4965 arrow to point to the line specified. Also, "info line" prints
4966 addresses in symbolic form (as well as hex).
4968 All vxworks based targets now support a user settable option, called
4969 vxworks-timeout. This option represents the number of seconds gdb
4970 should wait for responses to rpc's. You might want to use this if
4971 your vxworks target is, perhaps, a slow software simulator or happens
4972 to be on the far side of a thin network line.
4976 This release contains support for using a DEC alpha as a GDB host for
4977 cross debugging. Native alpha debugging is not supported yet.
4980 *** Changes in GDB-4.9:
4984 This is the first GDB release which is accompanied by a matching testsuite.
4985 The testsuite requires installation of dejagnu, which should be available
4986 via ftp from most sites that carry GNU software.
4990 'Cfront' style demangling has had its name changed to 'ARM' style, to
4991 emphasize that it was written from the specifications in the C++ Annotated
4992 Reference Manual, not necessarily to be compatible with AT&T cfront. Despite
4993 disclaimers, it still generated too much confusion with users attempting to
4994 use gdb with AT&T cfront.
4998 GDB now uses a standard remote interface to a simulator library.
4999 So far, the library contains simulators for the Zilog Z8001/2, the
5000 Hitachi H8/300, H8/500 and Super-H.
5002 * New targets supported
5004 H8/300 simulator h8300-hitachi-hms or h8300hms
5005 H8/500 simulator h8500-hitachi-hms or h8500hms
5006 SH simulator sh-hitachi-hms or sh
5007 Z8000 simulator z8k-zilog-none or z8ksim
5008 IDT MIPS board over serial line mips-idt-ecoff
5010 Cross-debugging to GO32 targets is supported. It requires a custom
5011 version of the i386-stub.c module which is integrated with the
5012 GO32 memory extender.
5014 * New remote protocols
5016 MIPS remote debugging protocol.
5018 * New source languages supported
5020 This version includes preliminary support for Chill, a Pascal like language
5021 used by telecommunications companies. Chill support is also being integrated
5022 into the GNU compiler, but we don't know when it will be publically available.
5025 *** Changes in GDB-4.8:
5027 * HP Precision Architecture supported
5029 GDB now supports HP PA-RISC machines running HPUX. A preliminary
5030 version of this support was available as a set of patches from the
5031 University of Utah. GDB does not support debugging of programs
5032 compiled with the HP compiler, because HP will not document their file
5033 format. Instead, you must use GCC (version 2.3.2 or later) and PA-GAS
5034 (as available from jaguar.cs.utah.edu:/dist/pa-gas.u4.tar.Z).
5036 Many problems in the preliminary version have been fixed.
5038 * Faster and better demangling
5040 We have improved template demangling and fixed numerous bugs in the GNU style
5041 demangler. It can now handle type modifiers such as `static' or `const'. Wide
5042 character types (wchar_t) are now supported. Demangling of each symbol is now
5043 only done once, and is cached when the symbol table for a file is read in.
5044 This results in a small increase in memory usage for C programs, a moderate
5045 increase in memory usage for C++ programs, and a fantastic speedup in
5048 `Cfront' style demangling still doesn't work with AT&T cfront. It was written
5049 from the specifications in the Annotated Reference Manual, which AT&T's
5050 compiler does not actually implement.
5052 * G++ multiple inheritance compiler problem
5054 In the 2.3.2 release of gcc/g++, how the compiler resolves multiple
5055 inheritance lattices was reworked to properly discover ambiguities. We
5056 recently found an example which causes this new algorithm to fail in a
5057 very subtle way, producing bad debug information for those classes.
5058 The file 'gcc.patch' (in this directory) can be applied to gcc to
5059 circumvent the problem. A future GCC release will contain a complete
5062 The previous G++ debug info problem (mentioned below for the gdb-4.7
5063 release) is fixed in gcc version 2.3.2.
5065 * Improved configure script
5067 The `configure' script will now attempt to guess your system type if
5068 you don't supply a host system type. The old scheme of supplying a
5069 host system triplet is preferable over using this. All the magic is
5070 done in the new `config.guess' script. Examine it for details.
5072 We have also brought our configure script much more in line with the FSF's
5073 version. It now supports the --with-xxx options. In particular,
5074 `--with-minimal-bfd' can be used to make the GDB binary image smaller.
5075 The resulting GDB will not be able to read arbitrary object file formats --
5076 only the format ``expected'' to be used on the configured target system.
5077 We hope to make this the default in a future release.
5079 * Documentation improvements
5081 There's new internal documentation on how to modify GDB, and how to
5082 produce clean changes to the code. We implore people to read it
5083 before submitting changes.
5085 The GDB manual uses new, sexy Texinfo conditionals, rather than arcane
5086 M4 macros. The new texinfo.tex is provided in this release. Pre-built
5087 `info' files are also provided. To build `info' files from scratch,
5088 you will need the latest `makeinfo' release, which will be available in
5089 a future texinfo-X.Y release.
5091 *NOTE* The new texinfo.tex can cause old versions of TeX to hang.
5092 We're not sure exactly which versions have this problem, but it has
5093 been seen in 3.0. We highly recommend upgrading to TeX version 3.141
5094 or better. If that isn't possible, there is a patch in
5095 `texinfo/tex3patch' that will modify `texinfo/texinfo.tex' to work
5096 around this problem.
5100 GDB now supports array constants that can be used in expressions typed in by
5101 the user. The syntax is `{element, element, ...}'. Ie: you can now type
5102 `print {1, 2, 3}', and it will build up an array in memory malloc'd in
5105 The new directory `gdb/sparclite' contains a program that demonstrates
5106 how the sparc-stub.c remote stub runs on a Fujitsu SPARClite processor.
5108 * New native hosts supported
5110 HP/PA-RISC under HPUX using GNU tools hppa1.1-hp-hpux
5111 386 CPUs running SCO Unix 3.2v4 i386-unknown-sco3.2v4
5113 * New targets supported
5115 AMD 29k family via UDI a29k-amd-udi or udi29k
5117 * New file formats supported
5119 BFD now supports reading HP/PA-RISC executables (SOM file format?),
5120 HPUX core files, and SCO 3.2v2 core files.
5124 Attaching to processes now works again; thanks for the many bug reports.
5126 We have also stomped on a bunch of core dumps caused by
5127 printf_filtered("%s") problems.
5129 We eliminated a copyright problem on the rpc and ptrace header files
5130 for VxWorks, which was discovered at the last minute during the 4.7
5131 release. You should now be able to build a VxWorks GDB.
5133 You can now interrupt gdb while an attached process is running. This
5134 will cause the attached process to stop, and give control back to GDB.
5136 We fixed problems caused by using too many file descriptors
5137 for reading symbols from object files and libraries. This was
5138 especially a problem for programs that used many (~100) shared
5141 The `step' command now only enters a subroutine if there is line number
5142 information for the subroutine. Otherwise it acts like the `next'
5143 command. Previously, `step' would enter subroutines if there was
5144 any debugging information about the routine. This avoids problems
5145 when using `cc -g1' on MIPS machines.
5147 * Internal improvements
5149 GDB's internal interfaces have been improved to make it easier to support
5150 debugging of multiple languages in the future.
5152 GDB now uses a common structure for symbol information internally.
5153 Minimal symbols (derived from linkage symbols in object files), partial
5154 symbols (from a quick scan of debug information), and full symbols
5155 contain a common subset of information, making it easier to write
5156 shared code that handles any of them.
5158 * New command line options
5160 We now accept --silent as an alias for --quiet.
5164 The memory-mapped-malloc library is now licensed under the GNU Library
5165 General Public License.
5167 *** Changes in GDB-4.7:
5169 * Host/native/target split
5171 GDB has had some major internal surgery to untangle the support for
5172 hosts and remote targets. Now, when you configure GDB for a remote
5173 target, it will no longer load in all of the support for debugging
5174 local programs on the host. When fully completed and tested, this will
5175 ensure that arbitrary host/target combinations are possible.
5177 The primary conceptual shift is to separate the non-portable code in
5178 GDB into three categories. Host specific code is required any time GDB
5179 is compiled on that host, regardless of the target. Target specific
5180 code relates to the peculiarities of the target, but can be compiled on
5181 any host. Native specific code is everything else: it can only be
5182 built when the host and target are the same system. Child process
5183 handling and core file support are two common `native' examples.
5185 GDB's use of /proc for controlling Unix child processes is now cleaner.
5186 It has been split out into a single module under the `target_ops' vector,
5187 plus two native-dependent functions for each system that uses /proc.
5189 * New hosts supported
5191 HP/Apollo 68k (under the BSD domain) m68k-apollo-bsd or apollo68bsd
5192 386 CPUs running various BSD ports i386-unknown-bsd or 386bsd
5193 386 CPUs running SCO Unix i386-unknown-scosysv322 or i386sco
5195 * New targets supported
5197 Fujitsu SPARClite sparclite-fujitsu-none or sparclite
5198 68030 and CPU32 m68030-*-*, m68332-*-*
5200 * New native hosts supported
5202 386 CPUs running various BSD ports i386-unknown-bsd or 386bsd
5203 (386bsd is not well tested yet)
5204 386 CPUs running SCO Unix i386-unknown-scosysv322 or sco
5206 * New file formats supported
5208 BFD now supports COFF files for the Zilog Z8000 microprocessor. It
5209 supports reading of `a.out.adobe' object files, which are an a.out
5210 format extended with minimal information about multiple sections.
5214 `show copying' is the same as the old `info copying'.
5215 `show warranty' is the same as `info warrantee'.
5216 These were renamed for consistency. The old commands continue to work.
5218 `info handle' is a new alias for `info signals'.
5220 You can now define pre-command hooks, which attach arbitrary command
5221 scripts to any command. The commands in the hook will be executed
5222 prior to the user's command. You can also create a hook which will be
5223 executed whenever the program stops. See gdb.texinfo.
5227 We now deal with Cfront style name mangling, and can even extract type
5228 info from mangled symbols. GDB can automatically figure out which
5229 symbol mangling style your C++ compiler uses.
5231 Calling of methods and virtual functions has been improved as well.
5235 The crash that occured when debugging Sun Ansi-C compiled binaries is
5236 fixed. This was due to mishandling of the extra N_SO stabs output
5239 We also finally got Ultrix 4.2 running in house, and fixed core file
5240 support, with help from a dozen people on the net.
5242 John M. Farrell discovered that the reason that single-stepping was so
5243 slow on all of the Mips based platforms (primarily SGI and DEC) was
5244 that we were trying to demangle and lookup a symbol used for internal
5245 purposes on every instruction that was being stepped through. Changing
5246 the name of that symbol so that it couldn't be mistaken for a C++
5247 mangled symbol sped things up a great deal.
5249 Rich Pixley sped up symbol lookups in general by getting much smarter
5250 about when C++ symbol mangling is necessary. This should make symbol
5251 completion (TAB on the command line) much faster. It's not as fast as
5252 we'd like, but it's significantly faster than gdb-4.6.
5256 A new user controllable variable 'call_scratch_address' can
5257 specify the location of a scratch area to be used when GDB
5258 calls a function in the target. This is necessary because the
5259 usual method of putting the scratch area on the stack does not work
5260 in systems that have separate instruction and data spaces.
5262 We integrated changes to support the 29k UDI (Universal Debugger
5263 Interface), but discovered at the last minute that we didn't have all
5264 of the appropriate copyright paperwork. We are working with AMD to
5265 resolve this, and hope to have it available soon.
5269 We have sped up the remote serial line protocol, especially for targets
5270 with lots of registers. It now supports a new `expedited status' ('T')
5271 message which can be used in place of the existing 'S' status message.
5272 This allows the remote stub to send only the registers that GDB
5273 needs to make a quick decision about single-stepping or conditional
5274 breakpoints, eliminating the need to fetch the entire register set for
5275 each instruction being stepped through.
5277 The GDB remote serial protocol now implements a write-through cache for
5278 registers, only re-reading the registers if the target has run.
5280 There is also a new remote serial stub for SPARC processors. You can
5281 find it in gdb-4.7/gdb/sparc-stub.c. This was written to support the
5282 Fujitsu SPARClite processor, but will run on any stand-alone SPARC
5283 processor with a serial port.
5287 Configure.in files have become much easier to read and modify. A new
5288 `table driven' format makes it more obvious what configurations are
5289 supported, and what files each one uses.
5293 There is a new opcodes library which will eventually contain all of the
5294 disassembly routines and opcode tables. At present, it only contains
5295 Sparc and Z8000 routines. This will allow the assembler, debugger, and
5296 disassembler (binutils/objdump) to share these routines.
5298 The libiberty library is now copylefted under the GNU Library General
5299 Public License. This allows more liberal use, and was done so libg++
5300 can use it. This makes no difference to GDB, since the Library License
5301 grants all the rights from the General Public License.
5305 The file gdb-4.7/gdb/doc/stabs.texinfo is a (relatively) complete
5306 reference to the stabs symbol info used by the debugger. It is (as far
5307 as we know) the only published document on this fascinating topic. We
5308 encourage you to read it, compare it to the stabs information on your
5309 system, and send improvements on the document in general (to
5310 bug-gdb@prep.ai.mit.edu).
5312 And, of course, many bugs have been fixed.
5315 *** Changes in GDB-4.6:
5317 * Better support for C++ function names
5319 GDB now accepts as input the "demangled form" of C++ overloaded function
5320 names and member function names, and can do command completion on such names
5321 (using TAB, TAB-TAB, and ESC-?). The names have to be quoted with a pair of
5322 single quotes. Examples are 'func (int, long)' and 'obj::operator==(obj&)'.
5323 Make use of command completion, it is your friend.
5325 GDB also now accepts a variety of C++ mangled symbol formats. They are
5326 the GNU g++ style, the Cfront (ARM) style, and the Lucid (lcc) style.
5327 You can tell GDB which format to use by doing a 'set demangle-style {gnu,
5328 lucid, cfront, auto}'. 'gnu' is the default. Do a 'set demangle-style foo'
5329 for the list of formats.
5331 * G++ symbol mangling problem
5333 Recent versions of gcc have a bug in how they emit debugging information for
5334 C++ methods (when using dbx-style stabs). The file 'gcc.patch' (in this
5335 directory) can be applied to gcc to fix the problem. Alternatively, if you
5336 can't fix gcc, you can #define GCC_MANGLE_BUG when compling gdb/symtab.c. The
5337 usual symptom is difficulty with setting breakpoints on methods. GDB complains
5338 about the method being non-existent. (We believe that version 2.2.2 of GCC has
5341 * New 'maintenance' command
5343 All of the commands related to hacking GDB internals have been moved out of
5344 the main command set, and now live behind the 'maintenance' command. This
5345 can also be abbreviated as 'mt'. The following changes were made:
5347 dump-me -> maintenance dump-me
5348 info all-breakpoints -> maintenance info breakpoints
5349 printmsyms -> maintenance print msyms
5350 printobjfiles -> maintenance print objfiles
5351 printpsyms -> maintenance print psymbols
5352 printsyms -> maintenance print symbols
5354 The following commands are new:
5356 maintenance demangle Call internal GDB demangler routine to
5357 demangle a C++ link name and prints the result.
5358 maintenance print type Print a type chain for a given symbol
5360 * Change to .gdbinit file processing
5362 We now read the $HOME/.gdbinit file before processing the argv arguments
5363 (e.g. reading symbol files or core files). This allows global parameters to
5364 be set, which will apply during the symbol reading. The ./.gdbinit is still
5365 read after argv processing.
5367 * New hosts supported
5369 Solaris-2.0 !!! sparc-sun-solaris2 or sun4sol2
5371 GNU/Linux support i386-unknown-linux or linux
5373 We are also including code to support the HP/PA running BSD and HPUX. This
5374 is almost guaranteed not to work, as we didn't have time to test or build it
5375 for this release. We are including it so that the more adventurous (or
5376 masochistic) of you can play with it. We also had major problems with the
5377 fact that the compiler that we got from HP doesn't support the -g option.
5380 * New targets supported
5382 Hitachi H8/300 h8300-hitachi-hms or h8300hms
5384 * More smarts about finding #include files
5386 GDB now remembers the compilation directory for all include files, and for
5387 all files from which C is generated (like yacc and lex sources). This
5388 greatly improves GDB's ability to find yacc/lex sources, and include files,
5389 especially if you are debugging your program from a directory different from
5390 the one that contains your sources.
5392 We also fixed a bug which caused difficulty with listing and setting
5393 breakpoints in include files which contain C code. (In the past, you had to
5394 try twice in order to list an include file that you hadn't looked at before.)
5396 * Interesting infernals change
5398 GDB now deals with arbitrary numbers of sections, where the symbols for each
5399 section must be relocated relative to that section's landing place in the
5400 target's address space. This work was needed to support ELF with embedded
5401 stabs used by Solaris-2.0.
5403 * Bug fixes (of course!)
5405 There have been loads of fixes for the following things:
5406 mips, rs6000, 29k/udi, m68k, g++, type handling, elf/dwarf, m88k,
5407 i960, stabs, DOS(GO32), procfs, etc...
5409 See the ChangeLog for details.
5411 *** Changes in GDB-4.5:
5413 * New machines supported (host and target)
5415 IBM RS6000 running AIX rs6000-ibm-aix or rs6000
5417 SGI Irix-4.x mips-sgi-irix4 or iris4
5419 * New malloc package
5421 GDB now uses a new memory manager called mmalloc, based on gmalloc.
5422 Mmalloc is capable of handling mutiple heaps of memory. It is also
5423 capable of saving a heap to a file, and then mapping it back in later.
5424 This can be used to greatly speedup the startup of GDB by using a
5425 pre-parsed symbol table which lives in a mmalloc managed heap. For
5426 more details, please read mmalloc/mmalloc.texi.
5430 The 'info proc' command (SVR4 only) has been enhanced quite a bit. See
5431 'help info proc' for details.
5433 * MIPS ecoff symbol table format
5435 The code that reads MIPS symbol table format is now supported on all hosts.
5436 Thanks to MIPS for releasing the sym.h and symconst.h files to make this
5439 * File name changes for MS-DOS
5441 Many files in the config directories have been renamed to make it easier to
5442 support GDB on MS-DOSe systems (which have very restrictive file name
5443 conventions :-( ). MS-DOSe host support (under DJ Delorie's GO32
5444 environment) is close to working but has some remaining problems. Note
5445 that debugging of DOS programs is not supported, due to limitations
5446 in the ``operating system'', but it can be used to host cross-debugging.
5448 * Cross byte order fixes
5450 Many fixes have been made to support cross debugging of Sparc and MIPS
5451 targets from hosts whose byte order differs.
5453 * New -mapped and -readnow options
5455 If memory-mapped files are available on your system through the 'mmap'
5456 system call, you can use the -mapped option on the `file' or
5457 `symbol-file' commands to cause GDB to write the symbols from your
5458 program into a reusable file. If the program you are debugging is
5459 called `/path/fred', the mapped symbol file will be `./fred.syms'.
5460 Future GDB debugging sessions will notice the presence of this file,
5461 and will quickly map in symbol information from it, rather than reading
5462 the symbol table from the executable program. Using the '-mapped'
5463 option in a GDB `file' or `symbol-file' command has the same effect as
5464 starting GDB with the '-mapped' command-line option.
5466 You can cause GDB to read the entire symbol table immediately by using
5467 the '-readnow' option with any of the commands that load symbol table
5468 information (or on the GDB command line). This makes the command
5469 slower, but makes future operations faster.
5471 The -mapped and -readnow options are typically combined in order to
5472 build a `fred.syms' file that contains complete symbol information.
5473 A simple GDB invocation to do nothing but build a `.syms' file for future
5476 gdb -batch -nx -mapped -readnow programname
5478 The `.syms' file is specific to the host machine on which GDB is run.
5479 It holds an exact image of GDB's internal symbol table. It cannot be
5480 shared across multiple host platforms.
5482 * longjmp() handling
5484 GDB is now capable of stepping and nexting over longjmp(), _longjmp(), and
5485 siglongjmp() without losing control. This feature has not yet been ported to
5486 all systems. It currently works on many 386 platforms, all MIPS-based
5487 platforms (SGI, DECstation, etc), and Sun3/4.
5491 Preliminary work has been put in to support the new Solaris OS from Sun. At
5492 this time, it can control and debug processes, but it is not capable of
5497 As always, many many bug fixes. The major areas were with g++, and mipsread.
5498 People using the MIPS-based platforms should experience fewer mysterious
5499 crashes and trashed symbol tables.
5501 *** Changes in GDB-4.4:
5503 * New machines supported (host and target)
5505 SCO Unix on i386 IBM PC clones i386-sco-sysv or i386sco
5507 BSD Reno on Vax vax-dec-bsd
5508 Ultrix on Vax vax-dec-ultrix
5510 * New machines supported (target)
5512 AMD 29000 embedded, using EBMON a29k-none-none
5516 GDB continues to improve its handling of C++. `References' work better.
5517 The demangler has also been improved, and now deals with symbols mangled as
5518 per the Annotated C++ Reference Guide.
5520 GDB also now handles `stabs' symbol information embedded in MIPS
5521 `ecoff' symbol tables. Since the ecoff format was not easily
5522 extensible to handle new languages such as C++, this appeared to be a
5523 good way to put C++ debugging info into MIPS binaries. This option
5524 will be supported in the GNU C compiler, version 2, when it is
5527 * New features for SVR4
5529 GDB now handles SVR4 shared libraries, in the same fashion as SunOS
5530 shared libraries. Debugging dynamically linked programs should present
5531 only minor differences from debugging statically linked programs.
5533 The `info proc' command will print out information about any process
5534 on an SVR4 system (including the one you are debugging). At the moment,
5535 it prints the address mappings of the process.
5537 If you bring up GDB on another SVR4 system, please send mail to
5538 bug-gdb@prep.ai.mit.edu to let us know what changes were reqired (if any).
5540 * Better dynamic linking support in SunOS
5542 Reading symbols from shared libraries which contain debugging symbols
5543 now works properly. However, there remain issues such as automatic
5544 skipping of `transfer vector' code during function calls, which
5545 make it harder to debug code in a shared library, than to debug the
5546 same code linked statically.
5550 GDB is now using the latest `getopt' routines from the FSF. This
5551 version accepts the -- prefix for options with long names. GDB will
5552 continue to accept the old forms (-option and +option) as well.
5553 Various single letter abbreviations for options have been explicity
5554 added to the option table so that they won't get overshadowed in the
5555 future by other options that begin with the same letter.
5559 The `cleanup_undefined_types' bug that many of you noticed has been squashed.
5560 Many assorted bugs have been handled. Many more remain to be handled.
5561 See the various ChangeLog files (primarily in gdb and bfd) for details.
5564 *** Changes in GDB-4.3:
5566 * New machines supported (host and target)
5568 Amiga 3000 running Amix m68k-cbm-svr4 or amix
5569 NCR 3000 386 running SVR4 i386-ncr-svr4 or ncr3000
5570 Motorola Delta 88000 running Sys V m88k-motorola-sysv or delta88
5572 * Almost SCO Unix support
5574 We had hoped to support:
5575 SCO Unix on i386 IBM PC clones i386-sco-sysv or i386sco
5576 (except for core file support), but we discovered very late in the release
5577 that it has problems with process groups that render gdb unusable. Sorry
5578 about that. I encourage people to fix it and post the fixes.
5580 * Preliminary ELF and DWARF support
5582 GDB can read ELF object files on System V Release 4, and can handle
5583 debugging records for C, in DWARF format, in ELF files. This support
5584 is preliminary. If you bring up GDB on another SVR4 system, please
5585 send mail to bug-gdb@prep.ai.mit.edu to let us know what changes were
5590 GDB now uses the latest `readline' library. One user-visible change
5591 is that two tabs will list possible command completions, which previously
5592 required typing M-? (meta-question mark, or ESC ?).
5596 The `stepi' bug that many of you noticed has been squashed.
5597 Many bugs in C++ have been handled. Many more remain to be handled.
5598 See the various ChangeLog files (primarily in gdb and bfd) for details.
5600 * State of the MIPS world (in case you wondered):
5602 GDB can understand the symbol tables emitted by the compilers
5603 supplied by most vendors of MIPS-based machines, including DEC. These
5604 symbol tables are in a format that essentially nobody else uses.
5606 Some versions of gcc come with an assembler post-processor called
5607 mips-tfile. This program is required if you want to do source-level
5608 debugging of gcc-compiled programs. I believe FSF does not ship
5609 mips-tfile with gcc version 1, but it will eventually come with gcc
5612 Debugging of g++ output remains a problem. g++ version 1.xx does not
5613 really support it at all. (If you're lucky, you should be able to get
5614 line numbers and stack traces to work, but no parameters or local
5615 variables.) With some work it should be possible to improve the
5618 When gcc version 2 is released, you will have somewhat better luck.
5619 However, even then you will get confusing results for inheritance and
5622 We will eventually provide full debugging of g++ output on
5623 DECstations. This will probably involve some kind of stabs-in-ecoff
5624 encapulation, but the details have not been worked out yet.
5627 *** Changes in GDB-4.2:
5629 * Improved configuration
5631 Only one copy of `configure' exists now, and it is not self-modifying.
5632 Porting BFD is simpler.
5636 The `step' and `next' commands now only stop at the first instruction
5637 of a source line. This prevents the multiple stops that used to occur
5638 in switch statements, for-loops, etc. `Step' continues to stop if a
5639 function that has debugging information is called within the line.
5643 Lots of small bugs fixed. More remain.
5645 * New host supported (not target)
5647 Intel 386 PC clone running Mach i386-none-mach
5650 *** Changes in GDB-4.1:
5652 * Multiple source language support
5654 GDB now has internal scaffolding to handle several source languages.
5655 It determines the type of each source file from its filename extension,
5656 and will switch expression parsing and number formatting to match the
5657 language of the function in the currently selected stack frame.
5658 You can also specifically set the language to be used, with
5659 `set language c' or `set language modula-2'.
5663 GDB now has preliminary support for the GNU Modula-2 compiler,
5664 currently under development at the State University of New York at
5665 Buffalo. Development of both GDB and the GNU Modula-2 compiler will
5666 continue through the fall of 1991 and into 1992.
5668 Other Modula-2 compilers are currently not supported, and attempting to
5669 debug programs compiled with them will likely result in an error as the
5670 symbol table is read. Feel free to work on it, though!
5672 There are hooks in GDB for strict type checking and range checking,
5673 in the `Modula-2 philosophy', but they do not currently work.
5677 GDB can now write to executable and core files (e.g. patch
5678 a variable's value). You must turn this switch on, specify
5679 the file ("exec foo" or "core foo"), *then* modify it, e.g.
5680 by assigning a new value to a variable. Modifications take
5683 * Automatic SunOS shared library reading
5685 When you run your program, GDB automatically determines where its
5686 shared libraries (if any) have been loaded, and reads their symbols.
5687 The `share' command is no longer needed. This also works when
5688 examining core files.
5692 You can specify the number of lines that the `list' command shows.
5695 * New machines supported (host and target)
5697 SGI Iris (MIPS) running Irix V3: mips-sgi-irix or iris
5698 Sony NEWS (68K) running NEWSOS 3.x: m68k-sony-sysv or news
5699 Ultracomputer (29K) running Sym1: a29k-nyu-sym1 or ultra3
5701 * New hosts supported (not targets)
5703 IBM RT/PC: romp-ibm-aix or rtpc
5705 * New targets supported (not hosts)
5707 AMD 29000 embedded with COFF a29k-none-coff
5708 AMD 29000 embedded with a.out a29k-none-aout
5709 Ultracomputer remote kernel debug a29k-nyu-kern
5711 * New remote interfaces
5717 *** Changes in GDB-4.0:
5721 Wide output is wrapped at good places to make the output more readable.
5723 Gdb now supports cross-debugging from a host machine of one type to a
5724 target machine of another type. Communication with the target system
5725 is over serial lines. The ``target'' command handles connecting to the
5726 remote system; the ``load'' command will download a program into the
5727 remote system. Serial stubs for the m68k and i386 are provided. Gdb
5728 also supports debugging of realtime processes running under VxWorks,
5729 using SunRPC Remote Procedure Calls over TCP/IP to talk to a debugger
5730 stub on the target system.
5732 New CPUs supported include the AMD 29000 and Intel 960.
5734 GDB now reads object files and symbol tables via a ``binary file''
5735 library, which allows a single copy of GDB to debug programs of multiple
5736 object file types such as a.out and coff.
5738 There is now a GDB reference card in "doc/refcard.tex". (Make targets
5739 refcard.dvi and refcard.ps are available to format it).
5742 * Control-Variable user interface simplified
5744 All variables that control the operation of the debugger can be set
5745 by the ``set'' command, and displayed by the ``show'' command.
5747 For example, ``set prompt new-gdb=>'' will change your prompt to new-gdb=>.
5748 ``Show prompt'' produces the response:
5749 Gdb's prompt is new-gdb=>.
5751 What follows are the NEW set commands. The command ``help set'' will
5752 print a complete list of old and new set commands. ``help set FOO''
5753 will give a longer description of the variable FOO. ``show'' will show
5754 all of the variable descriptions and their current settings.
5756 confirm on/off: Enables warning questions for operations that are
5757 hard to recover from, e.g. rerunning the program while
5758 it is already running. Default is ON.
5760 editing on/off: Enables EMACS style command line editing
5761 of input. Previous lines can be recalled with
5762 control-P, the current line can be edited with control-B,
5763 you can search for commands with control-R, etc.
5766 history filename NAME: NAME is where the gdb command history
5767 will be stored. The default is .gdb_history,
5768 or the value of the environment variable
5771 history size N: The size, in commands, of the command history. The
5772 default is 256, or the value of the environment variable
5775 history save on/off: If this value is set to ON, the history file will
5776 be saved after exiting gdb. If set to OFF, the
5777 file will not be saved. The default is OFF.
5779 history expansion on/off: If this value is set to ON, then csh-like
5780 history expansion will be performed on
5781 command line input. The default is OFF.
5783 radix N: Sets the default radix for input and output. It can be set
5784 to 8, 10, or 16. Note that the argument to "radix" is interpreted
5785 in the current radix, so "set radix 10" is always a no-op.
5787 height N: This integer value is the number of lines on a page. Default
5788 is 24, the current `stty rows'' setting, or the ``li#''
5789 setting from the termcap entry matching the environment
5792 width N: This integer value is the number of characters on a line.
5793 Default is 80, the current `stty cols'' setting, or the ``co#''
5794 setting from the termcap entry matching the environment
5797 Note: ``set screensize'' is obsolete. Use ``set height'' and
5798 ``set width'' instead.
5800 print address on/off: Print memory addresses in various command displays,
5801 such as stack traces and structure values. Gdb looks
5802 more ``symbolic'' if you turn this off; it looks more
5803 ``machine level'' with it on. Default is ON.
5805 print array on/off: Prettyprint arrays. New convenient format! Default
5808 print demangle on/off: Print C++ symbols in "source" form if on,
5811 print asm-demangle on/off: Same, for assembler level printouts
5814 print vtbl on/off: Prettyprint C++ virtual function tables. Default is OFF.
5817 * Support for Epoch Environment.
5819 The epoch environment is a version of Emacs v18 with windowing. One
5820 new command, ``inspect'', is identical to ``print'', except that if you
5821 are running in the epoch environment, the value is printed in its own
5825 * Support for Shared Libraries
5827 GDB can now debug programs and core files that use SunOS shared libraries.
5828 Symbols from a shared library cannot be referenced
5829 before the shared library has been linked with the program (this
5830 happens after you type ``run'' and before the function main() is entered).
5831 At any time after this linking (including when examining core files
5832 from dynamically linked programs), gdb reads the symbols from each
5833 shared library when you type the ``sharedlibrary'' command.
5834 It can be abbreviated ``share''.
5836 sharedlibrary REGEXP: Load shared object library symbols for files
5837 matching a unix regular expression. No argument
5838 indicates to load symbols for all shared libraries.
5840 info sharedlibrary: Status of loaded shared libraries.
5845 A watchpoint stops execution of a program whenever the value of an
5846 expression changes. Checking for this slows down execution
5847 tremendously whenever you are in the scope of the expression, but is
5848 quite useful for catching tough ``bit-spreader'' or pointer misuse
5849 problems. Some machines such as the 386 have hardware for doing this
5850 more quickly, and future versions of gdb will use this hardware.
5852 watch EXP: Set a watchpoint (breakpoint) for an expression.
5854 info watchpoints: Information about your watchpoints.
5856 delete N: Deletes watchpoint number N (same as breakpoints).
5857 disable N: Temporarily turns off watchpoint number N (same as breakpoints).
5858 enable N: Re-enables watchpoint number N (same as breakpoints).
5861 * C++ multiple inheritance
5863 When used with a GCC version 2 compiler, GDB supports multiple inheritance
5866 * C++ exception handling
5868 Gdb now supports limited C++ exception handling. Besides the existing
5869 ability to breakpoint on an exception handler, gdb can breakpoint on
5870 the raising of an exception (before the stack is peeled back to the
5873 catch FOO: If there is a FOO exception handler in the dynamic scope,
5874 set a breakpoint to catch exceptions which may be raised there.
5875 Multiple exceptions (``catch foo bar baz'') may be caught.
5877 info catch: Lists all exceptions which may be caught in the
5878 current stack frame.
5881 * Minor command changes
5883 The command ``call func (arg, arg, ...)'' now acts like the print
5884 command, except it does not print or save a value if the function's result
5885 is void. This is similar to dbx usage.
5887 The ``up'' and ``down'' commands now always print the frame they end up
5888 at; ``up-silently'' and `down-silently'' can be used in scripts to change
5889 frames without printing.
5891 * New directory command
5893 'dir' now adds directories to the FRONT of the source search path.
5894 The path starts off empty. Source files that contain debug information
5895 about the directory in which they were compiled can be found even
5896 with an empty path; Sun CC and GCC include this information. If GDB can't
5897 find your source file in the current directory, type "dir .".
5899 * Configuring GDB for compilation
5901 For normal use, type ``./configure host''. See README or gdb.texinfo
5904 GDB now handles cross debugging. If you are remotely debugging between
5905 two different machines, type ``./configure host -target=targ''.
5906 Host is the machine where GDB will run; targ is the machine
5907 where the program that you are debugging will run.