1 What has changed in GDB?
2 (Organized release by release)
4 *** Changes in GDB-4.16:
6 * New native configurations
8 Windows 95, x86 Windows NT i[345]86-*-cygwin32
9 M68K NetBSD m68k-*-netbsd*
10 PowerPC AIX 4.x powerpc-*-aix*
11 PowerPC MacOS powerpc-*-macos*
12 PowerPC Windows NT powerpcle-*-cygwin32
13 RS/6000 AIX 4.x rs6000-*-aix4*
17 ARM with RDP protocol arm-*-*
18 I960 with MON960 i960-*-coff
19 MIPS VxWorks mips*-*-vxworks*
20 MIPS VR4300 with PMON mips64*vr4300{,el}-*-elf*
21 PowerPC with PPCBUG monitor powerpc{,le}-*-eabi*
23 Matra Sparclet sparclet-*-*
27 The powerpc-eabi configuration now includes the PSIM simulator,
28 contributed by Andrew Cagney, with assistance from Mike Meissner.
29 PSIM is a very elaborate model of the PowerPC, including not only
30 basic instruction set execution, but also details of execution unit
31 performance and I/O hardware. See sim/ppc/README for more details.
35 GDB now works with Solaris 2.5.
37 * Windows 95/NT native
39 GDB will now work as a native debugger on Windows 95 and Windows NT.
40 To build it from source, you must use the "gnu-win32" environment,
41 which uses a DLL to emulate enough of Unix to run the GNU tools.
42 Further information, binaries, and sources are available at
43 ftp.cygnus.com, under pub/gnu-win32.
47 If a user-defined command includes the command `dont-repeat', then the
48 command will not be repeated if the user just types return. This is
49 useful if the command is time-consuming to run, so that accidental
50 extra keystrokes don't run the same command many times.
52 * Send break instead of ^C
54 The standard remote protocol now includes an option to send a break
55 rather than a ^C to the target in order to interrupt it. By default,
56 GDB will send ^C; to send a break, set the variable `remotebreak' to 1.
58 * Remote protocol timeout
60 The standard remote protocol includes a new variable `remotetimeout'
61 that allows you to set the number of seconds before GDB gives up trying
62 to read from the target. The default value is 2.
64 * Automatic tracking of dynamic object loading (HPUX and Solaris only)
66 By default GDB will automatically keep track of objects as they are
67 loaded and unloaded by the dynamic linker. By using the command `set
68 stop-on-solib-events 1' you can arrange for GDB to stop the inferior
69 when shared library events occur, thus allowing you to set breakpoints
70 in shared libraries which are explicitly loaded by the inferior.
72 Note this feature does not work on hpux8. On hpux9 you must link
73 /usr/lib/end.o into your program. This feature should work
74 automatically on hpux10.
76 * Irix 5.x hardware watchpoint support
78 Irix 5 configurations now support the use of hardware watchpoints.
80 * Mips protocol "SYN garbage limit"
82 When debugging a Mips target using the `target mips' protocol, you
83 may set the number of characters that GDB will ignore by setting
84 the `syn-garbage-limit'. A value of -1 means that GDB will ignore
85 every character. The default value is 1050.
87 * Recording and replaying remote debug sessions
89 If you set `remotelogfile' to the name of a file, gdb will write to it
90 a recording of a remote debug session. This recording may then be
91 replayed back to gdb using "gdbreplay". See gdbserver/README for
92 details. This is useful when you have a problem with GDB while doing
93 remote debugging; you can make a recording of the session and send it
94 to someone else, who can then recreate the problem.
96 * Speedups for remote debugging
98 GDB includes speedups for downloading and stepping MIPS systems using
99 the IDT monitor, fast downloads to the Hitachi SH E7000 emulator,
100 and more efficient S-record downloading.
102 * Memory use reductions and statistics collection
104 GDB now uses less memory and reports statistics about memory usage.
105 Try the `maint print statistics' command, for example.
107 *** Changes in GDB-4.15:
111 The symbol reader for AIX GDB now uses partial symbol tables. This
112 can greatly improve startup time, especially for large executables.
114 * Remote targets use caching
116 Remote targets now use a data cache to speed up communication with the
117 remote side. The data cache could lead to incorrect results because
118 it doesn't know about volatile variables, thus making it impossible to
119 debug targets which use memory mapped I/O devices. `set remotecache
120 off' turns the the data cache off.
122 * Remote targets may have threads
124 The standard remote protocol now includes support for multiple threads
125 in the target system, using new protocol commands 'H' and 'T'. See
126 gdb/remote.c for details.
130 If GDB is configured with `--enable-netrom', then it will include
131 support for the NetROM ROM emulator from XLNT Designs. The NetROM
132 acts as though it is a bank of ROM on the target board, but you can
133 write into it over the network. GDB's support consists only of
134 support for fast loading into the emulated ROM; to debug, you must use
135 another protocol, such as standard remote protocol. The usual
136 sequence is something like
138 target nrom <netrom-hostname>
140 target remote <netrom-hostname>:1235
144 GDB now includes support for the Apple Macintosh, as a host only. It
145 may be run as either an MPW tool or as a standalone application, and
146 it can debug through the serial port. All the usual GDB commands are
147 available, but to the target command, you must supply "serial" as the
148 device type instead of "/dev/ttyXX". See mpw-README in the main
149 directory for more information on how to build. The MPW configuration
150 scripts */mpw-config.in support only a few targets, and only the
151 mips-idt-ecoff target has been tested.
155 GDB configuration now uses autoconf. This is not user-visible,
156 but does simplify configuration and building.
160 GDB now supports hpux10.
162 *** Changes in GDB-4.14:
164 * New native configurations
166 x86 FreeBSD i[345]86-*-freebsd
167 x86 NetBSD i[345]86-*-netbsd
168 NS32k NetBSD ns32k-*-netbsd
169 Sparc NetBSD sparc-*-netbsd
173 A29K VxWorks a29k-*-vxworks
174 HP PA PRO embedded (WinBond W89K & Oki OP50N) hppa*-*-pro*
175 CPU32 EST-300 emulator m68*-*-est*
176 PowerPC ELF powerpc-*-elf
179 * Alpha OSF/1 support for procfs
181 GDB now supports procfs under OSF/1-2.x and higher, which makes it
182 possible to attach to running processes. As the mounting of the /proc
183 filesystem is optional on the Alpha, GDB automatically determines
184 the availability of /proc during startup. This can lead to problems
185 if /proc is unmounted after GDB has been started.
187 * Arguments to user-defined commands
189 User commands may accept up to 10 arguments separated by whitespace.
190 Arguments are accessed within the user command via $arg0..$arg9. A
193 print $arg0 + $arg1 + $arg2
195 To execute the command use:
198 Defines the command "adder" which prints the sum of its three arguments.
199 Note the arguments are text substitutions, so they may reference variables,
200 use complex expressions, or even perform inferior function calls.
202 * New `if' and `while' commands
204 This makes it possible to write more sophisticated user-defined
205 commands. Both commands take a single argument, which is the
206 expression to evaluate, and must be followed by the commands to
207 execute, one per line, if the expression is nonzero, the list being
208 terminated by the word `end'. The `if' command list may include an
209 `else' word, which causes the following commands to be executed only
210 if the expression is zero.
212 * Fortran source language mode
214 GDB now includes partial support for Fortran 77. It will recognize
215 Fortran programs and can evaluate a subset of Fortran expressions, but
216 variables and functions may not be handled correctly. GDB will work
217 with G77, but does not yet know much about symbols emitted by other
220 * Better HPUX support
222 Most debugging facilities now work on dynamic executables for HPPAs
223 running hpux9 or later. You can attach to running dynamically linked
224 processes, but by default the dynamic libraries will be read-only, so
225 for instance you won't be able to put breakpoints in them. To change
226 that behavior do the following before running the program:
232 This will cause the libraries to be mapped private and read-write.
233 To revert to the normal behavior, do this:
239 You cannot set breakpoints or examine data in the library until after
240 the library is loaded if the function/data symbols do not have
243 GDB can now also read debug symbols produced by the HP C compiler on
244 HPPAs (sorry, no C++, Fortran or 68k support).
246 * Target byte order now dynamically selectable
248 You can choose which byte order to use with a target system, via the
249 commands "set endian big" and "set endian little", and you can see the
250 current setting by using "show endian". You can also give the command
251 "set endian auto", in which case GDB will use the byte order
252 associated with the executable. Currently, only embedded MIPS
253 configurations support dynamic selection of target byte order.
255 * New DOS host serial code
257 This version uses DPMI interrupts to handle buffered I/O, so you
258 no longer need to run asynctsr when debugging boards connected to
261 *** Changes in GDB-4.13:
263 * New "complete" command
265 This lists all the possible completions for the rest of the line, if it
266 were to be given as a command itself. This is intended for use by emacs.
268 * Trailing space optional in prompt
270 "set prompt" no longer adds a space for you after the prompt you set. This
271 allows you to set a prompt which ends in a space or one that does not.
273 * Breakpoint hit counts
275 "info break" now displays a count of the number of times the breakpoint
276 has been hit. This is especially useful in conjunction with "ignore"; you
277 can ignore a large number of breakpoint hits, look at the breakpoint info
278 to see how many times the breakpoint was hit, then run again, ignoring one
279 less than that number, and this will get you quickly to the last hit of
282 * Ability to stop printing at NULL character
284 "set print null-stop" will cause GDB to stop printing the characters of
285 an array when the first NULL is encountered. This is useful when large
286 arrays actually contain only short strings.
288 * Shared library breakpoints
290 In SunOS 4.x, SVR4, and Alpha OSF/1 configurations, you can now set
291 breakpoints in shared libraries before the executable is run.
293 * Hardware watchpoints
295 There is a new hardware breakpoint for the watch command for sparclite
296 targets. See gdb/sparclite/hw_breakpoint.note.
298 Hardware watchpoints are also now supported under Linux.
302 Annotations have been added. These are for use with graphical interfaces,
303 and are still experimental. Currently only gdba.el uses these.
305 * Improved Irix 5 support
307 GDB now works properly with Irix 5.2.
309 * Improved HPPA support
311 GDB now works properly with the latest GCC and GAS.
313 * New native configurations
315 Sequent PTX4 i[34]86-sequent-ptx4
316 HPPA running OSF/1 hppa*-*-osf*
317 Atari TT running SVR4 m68*-*-sysv4*
318 RS/6000 LynxOS rs6000-*-lynxos*
322 OS/9000 i[34]86-*-os9k
323 MIPS R4000 mips64*{,el}-*-{ecoff,elf}
326 * Hitachi SH7000 and E7000-PC ICE support
328 There is now support for communicating with the Hitachi E7000-PC ICE.
329 This is available automatically when GDB is configured for the SH.
333 As usual, a variety of small fixes and improvements, both generic
334 and configuration-specific. See the ChangeLog for more detail.
336 *** Changes in GDB-4.12:
338 * Irix 5 is now supported
342 GDB-4.12 on the HPPA has a number of changes which make it unable
343 to debug the output from the currently released versions of GCC and
344 GAS (GCC 2.5.8 and GAS-2.2 or PAGAS-1.36). Until the next major release
345 of GCC and GAS, versions of these tools designed to work with GDB-4.12
346 can be retrieved via anonymous ftp from jaguar.cs.utah.edu:/dist.
349 *** Changes in GDB-4.11:
351 * User visible changes:
355 The "set remotedebug" option is now consistent between the mips remote
356 target, remote targets using the gdb-specific protocol, UDI (AMD's
357 debug protocol for the 29k) and the 88k bug monitor. It is now an
358 integer specifying a debug level (normally 0 or 1, but 2 means more
359 debugging info for the mips target).
361 * DEC Alpha native support
363 GDB now works on the DEC Alpha. GCC 2.4.5 does not produce usable
364 debug info, but GDB works fairly well with the DEC compiler and should
365 work with a future GCC release. See the README file for a few
366 Alpha-specific notes.
368 * Preliminary thread implementation
370 GDB now has preliminary thread support for both SGI/Irix and LynxOS.
372 * LynxOS native and target support for 386
374 This release has been hosted on LynxOS 2.2, and also can be configured
375 to remotely debug programs running under LynxOS (see gdb/gdbserver/README
378 * Improvements in C++ mangling/demangling.
380 This release has much better g++ debugging, specifically in name
381 mangling/demangling, virtual function calls, print virtual table,
382 call methods, ...etc.
384 *** Changes in GDB-4.10:
386 * User visible changes:
388 Remote debugging using the GDB-specific (`target remote') protocol now
389 supports the `load' command. This is only useful if you have some
390 other way of getting the stub to the target system, and you can put it
391 somewhere in memory where it won't get clobbered by the download.
393 Filename completion now works.
395 When run under emacs mode, the "info line" command now causes the
396 arrow to point to the line specified. Also, "info line" prints
397 addresses in symbolic form (as well as hex).
399 All vxworks based targets now support a user settable option, called
400 vxworks-timeout. This option represents the number of seconds gdb
401 should wait for responses to rpc's. You might want to use this if
402 your vxworks target is, perhaps, a slow software simulator or happens
403 to be on the far side of a thin network line.
407 This release contains support for using a DEC alpha as a GDB host for
408 cross debugging. Native alpha debugging is not supported yet.
411 *** Changes in GDB-4.9:
415 This is the first GDB release which is accompanied by a matching testsuite.
416 The testsuite requires installation of dejagnu, which should be available
417 via ftp from most sites that carry GNU software.
421 'Cfront' style demangling has had its name changed to 'ARM' style, to
422 emphasize that it was written from the specifications in the C++ Annotated
423 Reference Manual, not necessarily to be compatible with AT&T cfront. Despite
424 disclaimers, it still generated too much confusion with users attempting to
425 use gdb with AT&T cfront.
429 GDB now uses a standard remote interface to a simulator library.
430 So far, the library contains simulators for the Zilog Z8001/2, the
431 Hitachi H8/300, H8/500 and Super-H.
433 * New targets supported
435 H8/300 simulator h8300-hitachi-hms or h8300hms
436 H8/500 simulator h8500-hitachi-hms or h8500hms
437 SH simulator sh-hitachi-hms or sh
438 Z8000 simulator z8k-zilog-none or z8ksim
439 IDT MIPS board over serial line mips-idt-ecoff
441 Cross-debugging to GO32 targets is supported. It requires a custom
442 version of the i386-stub.c module which is integrated with the
443 GO32 memory extender.
445 * New remote protocols
447 MIPS remote debugging protocol.
449 * New source languages supported
451 This version includes preliminary support for Chill, a Pascal like language
452 used by telecommunications companies. Chill support is also being integrated
453 into the GNU compiler, but we don't know when it will be publically available.
456 *** Changes in GDB-4.8:
458 * HP Precision Architecture supported
460 GDB now supports HP PA-RISC machines running HPUX. A preliminary
461 version of this support was available as a set of patches from the
462 University of Utah. GDB does not support debugging of programs
463 compiled with the HP compiler, because HP will not document their file
464 format. Instead, you must use GCC (version 2.3.2 or later) and PA-GAS
465 (as available from jaguar.cs.utah.edu:/dist/pa-gas.u4.tar.Z).
467 Many problems in the preliminary version have been fixed.
469 * Faster and better demangling
471 We have improved template demangling and fixed numerous bugs in the GNU style
472 demangler. It can now handle type modifiers such as `static' or `const'. Wide
473 character types (wchar_t) are now supported. Demangling of each symbol is now
474 only done once, and is cached when the symbol table for a file is read in.
475 This results in a small increase in memory usage for C programs, a moderate
476 increase in memory usage for C++ programs, and a fantastic speedup in
479 `Cfront' style demangling still doesn't work with AT&T cfront. It was written
480 from the specifications in the Annotated Reference Manual, which AT&T's
481 compiler does not actually implement.
483 * G++ multiple inheritance compiler problem
485 In the 2.3.2 release of gcc/g++, how the compiler resolves multiple
486 inheritance lattices was reworked to properly discover ambiguities. We
487 recently found an example which causes this new algorithm to fail in a
488 very subtle way, producing bad debug information for those classes.
489 The file 'gcc.patch' (in this directory) can be applied to gcc to
490 circumvent the problem. A future GCC release will contain a complete
493 The previous G++ debug info problem (mentioned below for the gdb-4.7
494 release) is fixed in gcc version 2.3.2.
496 * Improved configure script
498 The `configure' script will now attempt to guess your system type if
499 you don't supply a host system type. The old scheme of supplying a
500 host system triplet is preferable over using this. All the magic is
501 done in the new `config.guess' script. Examine it for details.
503 We have also brought our configure script much more in line with the FSF's
504 version. It now supports the --with-xxx options. In particular,
505 `--with-minimal-bfd' can be used to make the GDB binary image smaller.
506 The resulting GDB will not be able to read arbitrary object file formats --
507 only the format ``expected'' to be used on the configured target system.
508 We hope to make this the default in a future release.
510 * Documentation improvements
512 There's new internal documentation on how to modify GDB, and how to
513 produce clean changes to the code. We implore people to read it
514 before submitting changes.
516 The GDB manual uses new, sexy Texinfo conditionals, rather than arcane
517 M4 macros. The new texinfo.tex is provided in this release. Pre-built
518 `info' files are also provided. To build `info' files from scratch,
519 you will need the latest `makeinfo' release, which will be available in
520 a future texinfo-X.Y release.
522 *NOTE* The new texinfo.tex can cause old versions of TeX to hang.
523 We're not sure exactly which versions have this problem, but it has
524 been seen in 3.0. We highly recommend upgrading to TeX version 3.141
525 or better. If that isn't possible, there is a patch in
526 `texinfo/tex3patch' that will modify `texinfo/texinfo.tex' to work
531 GDB now supports array constants that can be used in expressions typed in by
532 the user. The syntax is `{element, element, ...}'. Ie: you can now type
533 `print {1, 2, 3}', and it will build up an array in memory malloc'd in
536 The new directory `gdb/sparclite' contains a program that demonstrates
537 how the sparc-stub.c remote stub runs on a Fujitsu SPARClite processor.
539 * New native hosts supported
541 HP/PA-RISC under HPUX using GNU tools hppa1.1-hp-hpux
542 386 CPUs running SCO Unix 3.2v4 i386-unknown-sco3.2v4
544 * New targets supported
546 AMD 29k family via UDI a29k-amd-udi or udi29k
548 * New file formats supported
550 BFD now supports reading HP/PA-RISC executables (SOM file format?),
551 HPUX core files, and SCO 3.2v2 core files.
555 Attaching to processes now works again; thanks for the many bug reports.
557 We have also stomped on a bunch of core dumps caused by
558 printf_filtered("%s") problems.
560 We eliminated a copyright problem on the rpc and ptrace header files
561 for VxWorks, which was discovered at the last minute during the 4.7
562 release. You should now be able to build a VxWorks GDB.
564 You can now interrupt gdb while an attached process is running. This
565 will cause the attached process to stop, and give control back to GDB.
567 We fixed problems caused by using too many file descriptors
568 for reading symbols from object files and libraries. This was
569 especially a problem for programs that used many (~100) shared
572 The `step' command now only enters a subroutine if there is line number
573 information for the subroutine. Otherwise it acts like the `next'
574 command. Previously, `step' would enter subroutines if there was
575 any debugging information about the routine. This avoids problems
576 when using `cc -g1' on MIPS machines.
578 * Internal improvements
580 GDB's internal interfaces have been improved to make it easier to support
581 debugging of multiple languages in the future.
583 GDB now uses a common structure for symbol information internally.
584 Minimal symbols (derived from linkage symbols in object files), partial
585 symbols (from a quick scan of debug information), and full symbols
586 contain a common subset of information, making it easier to write
587 shared code that handles any of them.
589 * New command line options
591 We now accept --silent as an alias for --quiet.
595 The memory-mapped-malloc library is now licensed under the GNU Library
596 General Public License.
598 *** Changes in GDB-4.7:
600 * Host/native/target split
602 GDB has had some major internal surgery to untangle the support for
603 hosts and remote targets. Now, when you configure GDB for a remote
604 target, it will no longer load in all of the support for debugging
605 local programs on the host. When fully completed and tested, this will
606 ensure that arbitrary host/target combinations are possible.
608 The primary conceptual shift is to separate the non-portable code in
609 GDB into three categories. Host specific code is required any time GDB
610 is compiled on that host, regardless of the target. Target specific
611 code relates to the peculiarities of the target, but can be compiled on
612 any host. Native specific code is everything else: it can only be
613 built when the host and target are the same system. Child process
614 handling and core file support are two common `native' examples.
616 GDB's use of /proc for controlling Unix child processes is now cleaner.
617 It has been split out into a single module under the `target_ops' vector,
618 plus two native-dependent functions for each system that uses /proc.
620 * New hosts supported
622 HP/Apollo 68k (under the BSD domain) m68k-apollo-bsd or apollo68bsd
623 386 CPUs running various BSD ports i386-unknown-bsd or 386bsd
624 386 CPUs running SCO Unix i386-unknown-scosysv322 or i386sco
626 * New targets supported
628 Fujitsu SPARClite sparclite-fujitsu-none or sparclite
629 68030 and CPU32 m68030-*-*, m68332-*-*
631 * New native hosts supported
633 386 CPUs running various BSD ports i386-unknown-bsd or 386bsd
634 (386bsd is not well tested yet)
635 386 CPUs running SCO Unix i386-unknown-scosysv322 or sco
637 * New file formats supported
639 BFD now supports COFF files for the Zilog Z8000 microprocessor. It
640 supports reading of `a.out.adobe' object files, which are an a.out
641 format extended with minimal information about multiple sections.
645 `show copying' is the same as the old `info copying'.
646 `show warranty' is the same as `info warrantee'.
647 These were renamed for consistency. The old commands continue to work.
649 `info handle' is a new alias for `info signals'.
651 You can now define pre-command hooks, which attach arbitrary command
652 scripts to any command. The commands in the hook will be executed
653 prior to the user's command. You can also create a hook which will be
654 executed whenever the program stops. See gdb.texinfo.
658 We now deal with Cfront style name mangling, and can even extract type
659 info from mangled symbols. GDB can automatically figure out which
660 symbol mangling style your C++ compiler uses.
662 Calling of methods and virtual functions has been improved as well.
666 The crash that occured when debugging Sun Ansi-C compiled binaries is
667 fixed. This was due to mishandling of the extra N_SO stabs output
670 We also finally got Ultrix 4.2 running in house, and fixed core file
671 support, with help from a dozen people on the net.
673 John M. Farrell discovered that the reason that single-stepping was so
674 slow on all of the Mips based platforms (primarily SGI and DEC) was
675 that we were trying to demangle and lookup a symbol used for internal
676 purposes on every instruction that was being stepped through. Changing
677 the name of that symbol so that it couldn't be mistaken for a C++
678 mangled symbol sped things up a great deal.
680 Rich Pixley sped up symbol lookups in general by getting much smarter
681 about when C++ symbol mangling is necessary. This should make symbol
682 completion (TAB on the command line) much faster. It's not as fast as
683 we'd like, but it's significantly faster than gdb-4.6.
687 A new user controllable variable 'call_scratch_address' can
688 specify the location of a scratch area to be used when GDB
689 calls a function in the target. This is necessary because the
690 usual method of putting the scratch area on the stack does not work
691 in systems that have separate instruction and data spaces.
693 We integrated changes to support the 29k UDI (Universal Debugger
694 Interface), but discovered at the last minute that we didn't have all
695 of the appropriate copyright paperwork. We are working with AMD to
696 resolve this, and hope to have it available soon.
700 We have sped up the remote serial line protocol, especially for targets
701 with lots of registers. It now supports a new `expedited status' ('T')
702 message which can be used in place of the existing 'S' status message.
703 This allows the remote stub to send only the registers that GDB
704 needs to make a quick decision about single-stepping or conditional
705 breakpoints, eliminating the need to fetch the entire register set for
706 each instruction being stepped through.
708 The GDB remote serial protocol now implements a write-through cache for
709 registers, only re-reading the registers if the target has run.
711 There is also a new remote serial stub for SPARC processors. You can
712 find it in gdb-4.7/gdb/sparc-stub.c. This was written to support the
713 Fujitsu SPARClite processor, but will run on any stand-alone SPARC
714 processor with a serial port.
718 Configure.in files have become much easier to read and modify. A new
719 `table driven' format makes it more obvious what configurations are
720 supported, and what files each one uses.
724 There is a new opcodes library which will eventually contain all of the
725 disassembly routines and opcode tables. At present, it only contains
726 Sparc and Z8000 routines. This will allow the assembler, debugger, and
727 disassembler (binutils/objdump) to share these routines.
729 The libiberty library is now copylefted under the GNU Library General
730 Public License. This allows more liberal use, and was done so libg++
731 can use it. This makes no difference to GDB, since the Library License
732 grants all the rights from the General Public License.
736 The file gdb-4.7/gdb/doc/stabs.texinfo is a (relatively) complete
737 reference to the stabs symbol info used by the debugger. It is (as far
738 as we know) the only published document on this fascinating topic. We
739 encourage you to read it, compare it to the stabs information on your
740 system, and send improvements on the document in general (to
741 bug-gdb@prep.ai.mit.edu).
743 And, of course, many bugs have been fixed.
746 *** Changes in GDB-4.6:
748 * Better support for C++ function names
750 GDB now accepts as input the "demangled form" of C++ overloaded function
751 names and member function names, and can do command completion on such names
752 (using TAB, TAB-TAB, and ESC-?). The names have to be quoted with a pair of
753 single quotes. Examples are 'func (int, long)' and 'obj::operator==(obj&)'.
754 Make use of command completion, it is your friend.
756 GDB also now accepts a variety of C++ mangled symbol formats. They are
757 the GNU g++ style, the Cfront (ARM) style, and the Lucid (lcc) style.
758 You can tell GDB which format to use by doing a 'set demangle-style {gnu,
759 lucid, cfront, auto}'. 'gnu' is the default. Do a 'set demangle-style foo'
760 for the list of formats.
762 * G++ symbol mangling problem
764 Recent versions of gcc have a bug in how they emit debugging information for
765 C++ methods (when using dbx-style stabs). The file 'gcc.patch' (in this
766 directory) can be applied to gcc to fix the problem. Alternatively, if you
767 can't fix gcc, you can #define GCC_MANGLE_BUG when compling gdb/symtab.c. The
768 usual symptom is difficulty with setting breakpoints on methods. GDB complains
769 about the method being non-existent. (We believe that version 2.2.2 of GCC has
772 * New 'maintenance' command
774 All of the commands related to hacking GDB internals have been moved out of
775 the main command set, and now live behind the 'maintenance' command. This
776 can also be abbreviated as 'mt'. The following changes were made:
778 dump-me -> maintenance dump-me
779 info all-breakpoints -> maintenance info breakpoints
780 printmsyms -> maintenance print msyms
781 printobjfiles -> maintenance print objfiles
782 printpsyms -> maintenance print psymbols
783 printsyms -> maintenance print symbols
785 The following commands are new:
787 maintenance demangle Call internal GDB demangler routine to
788 demangle a C++ link name and prints the result.
789 maintenance print type Print a type chain for a given symbol
791 * Change to .gdbinit file processing
793 We now read the $HOME/.gdbinit file before processing the argv arguments
794 (e.g. reading symbol files or core files). This allows global parameters to
795 be set, which will apply during the symbol reading. The ./.gdbinit is still
796 read after argv processing.
798 * New hosts supported
800 Solaris-2.0 !!! sparc-sun-solaris2 or sun4sol2
802 Linux support i386-unknown-linux or linux
804 We are also including code to support the HP/PA running BSD and HPUX. This
805 is almost guaranteed not to work, as we didn't have time to test or build it
806 for this release. We are including it so that the more adventurous (or
807 masochistic) of you can play with it. We also had major problems with the
808 fact that the compiler that we got from HP doesn't support the -g option.
811 * New targets supported
813 Hitachi H8/300 h8300-hitachi-hms or h8300hms
815 * More smarts about finding #include files
817 GDB now remembers the compilation directory for all include files, and for
818 all files from which C is generated (like yacc and lex sources). This
819 greatly improves GDB's ability to find yacc/lex sources, and include files,
820 especially if you are debugging your program from a directory different from
821 the one that contains your sources.
823 We also fixed a bug which caused difficulty with listing and setting
824 breakpoints in include files which contain C code. (In the past, you had to
825 try twice in order to list an include file that you hadn't looked at before.)
827 * Interesting infernals change
829 GDB now deals with arbitrary numbers of sections, where the symbols for each
830 section must be relocated relative to that section's landing place in the
831 target's address space. This work was needed to support ELF with embedded
832 stabs used by Solaris-2.0.
834 * Bug fixes (of course!)
836 There have been loads of fixes for the following things:
837 mips, rs6000, 29k/udi, m68k, g++, type handling, elf/dwarf, m88k,
838 i960, stabs, DOS(GO32), procfs, etc...
840 See the ChangeLog for details.
842 *** Changes in GDB-4.5:
844 * New machines supported (host and target)
846 IBM RS6000 running AIX rs6000-ibm-aix or rs6000
848 SGI Irix-4.x mips-sgi-irix4 or iris4
852 GDB now uses a new memory manager called mmalloc, based on gmalloc.
853 Mmalloc is capable of handling mutiple heaps of memory. It is also
854 capable of saving a heap to a file, and then mapping it back in later.
855 This can be used to greatly speedup the startup of GDB by using a
856 pre-parsed symbol table which lives in a mmalloc managed heap. For
857 more details, please read mmalloc/mmalloc.texi.
861 The 'info proc' command (SVR4 only) has been enhanced quite a bit. See
862 'help info proc' for details.
864 * MIPS ecoff symbol table format
866 The code that reads MIPS symbol table format is now supported on all hosts.
867 Thanks to MIPS for releasing the sym.h and symconst.h files to make this
870 * File name changes for MS-DOS
872 Many files in the config directories have been renamed to make it easier to
873 support GDB on MS-DOSe systems (which have very restrictive file name
874 conventions :-( ). MS-DOSe host support (under DJ Delorie's GO32
875 environment) is close to working but has some remaining problems. Note
876 that debugging of DOS programs is not supported, due to limitations
877 in the ``operating system'', but it can be used to host cross-debugging.
879 * Cross byte order fixes
881 Many fixes have been made to support cross debugging of Sparc and MIPS
882 targets from hosts whose byte order differs.
884 * New -mapped and -readnow options
886 If memory-mapped files are available on your system through the 'mmap'
887 system call, you can use the -mapped option on the `file' or
888 `symbol-file' commands to cause GDB to write the symbols from your
889 program into a reusable file. If the program you are debugging is
890 called `/path/fred', the mapped symbol file will be `./fred.syms'.
891 Future GDB debugging sessions will notice the presence of this file,
892 and will quickly map in symbol information from it, rather than reading
893 the symbol table from the executable program. Using the '-mapped'
894 option in a GDB `file' or `symbol-file' command has the same effect as
895 starting GDB with the '-mapped' command-line option.
897 You can cause GDB to read the entire symbol table immediately by using
898 the '-readnow' option with any of the commands that load symbol table
899 information (or on the GDB command line). This makes the command
900 slower, but makes future operations faster.
902 The -mapped and -readnow options are typically combined in order to
903 build a `fred.syms' file that contains complete symbol information.
904 A simple GDB invocation to do nothing but build a `.syms' file for future
907 gdb -batch -nx -mapped -readnow programname
909 The `.syms' file is specific to the host machine on which GDB is run.
910 It holds an exact image of GDB's internal symbol table. It cannot be
911 shared across multiple host platforms.
915 GDB is now capable of stepping and nexting over longjmp(), _longjmp(), and
916 siglongjmp() without losing control. This feature has not yet been ported to
917 all systems. It currently works on many 386 platforms, all MIPS-based
918 platforms (SGI, DECstation, etc), and Sun3/4.
922 Preliminary work has been put in to support the new Solaris OS from Sun. At
923 this time, it can control and debug processes, but it is not capable of
928 As always, many many bug fixes. The major areas were with g++, and mipsread.
929 People using the MIPS-based platforms should experience fewer mysterious
930 crashes and trashed symbol tables.
932 *** Changes in GDB-4.4:
934 * New machines supported (host and target)
936 SCO Unix on i386 IBM PC clones i386-sco-sysv or i386sco
938 BSD Reno on Vax vax-dec-bsd
939 Ultrix on Vax vax-dec-ultrix
941 * New machines supported (target)
943 AMD 29000 embedded, using EBMON a29k-none-none
947 GDB continues to improve its handling of C++. `References' work better.
948 The demangler has also been improved, and now deals with symbols mangled as
949 per the Annotated C++ Reference Guide.
951 GDB also now handles `stabs' symbol information embedded in MIPS
952 `ecoff' symbol tables. Since the ecoff format was not easily
953 extensible to handle new languages such as C++, this appeared to be a
954 good way to put C++ debugging info into MIPS binaries. This option
955 will be supported in the GNU C compiler, version 2, when it is
958 * New features for SVR4
960 GDB now handles SVR4 shared libraries, in the same fashion as SunOS
961 shared libraries. Debugging dynamically linked programs should present
962 only minor differences from debugging statically linked programs.
964 The `info proc' command will print out information about any process
965 on an SVR4 system (including the one you are debugging). At the moment,
966 it prints the address mappings of the process.
968 If you bring up GDB on another SVR4 system, please send mail to
969 bug-gdb@prep.ai.mit.edu to let us know what changes were reqired (if any).
971 * Better dynamic linking support in SunOS
973 Reading symbols from shared libraries which contain debugging symbols
974 now works properly. However, there remain issues such as automatic
975 skipping of `transfer vector' code during function calls, which
976 make it harder to debug code in a shared library, than to debug the
977 same code linked statically.
981 GDB is now using the latest `getopt' routines from the FSF. This
982 version accepts the -- prefix for options with long names. GDB will
983 continue to accept the old forms (-option and +option) as well.
984 Various single letter abbreviations for options have been explicity
985 added to the option table so that they won't get overshadowed in the
986 future by other options that begin with the same letter.
990 The `cleanup_undefined_types' bug that many of you noticed has been squashed.
991 Many assorted bugs have been handled. Many more remain to be handled.
992 See the various ChangeLog files (primarily in gdb and bfd) for details.
995 *** Changes in GDB-4.3:
997 * New machines supported (host and target)
999 Amiga 3000 running Amix m68k-cbm-svr4 or amix
1000 NCR 3000 386 running SVR4 i386-ncr-svr4 or ncr3000
1001 Motorola Delta 88000 running Sys V m88k-motorola-sysv or delta88
1003 * Almost SCO Unix support
1005 We had hoped to support:
1006 SCO Unix on i386 IBM PC clones i386-sco-sysv or i386sco
1007 (except for core file support), but we discovered very late in the release
1008 that it has problems with process groups that render gdb unusable. Sorry
1009 about that. I encourage people to fix it and post the fixes.
1011 * Preliminary ELF and DWARF support
1013 GDB can read ELF object files on System V Release 4, and can handle
1014 debugging records for C, in DWARF format, in ELF files. This support
1015 is preliminary. If you bring up GDB on another SVR4 system, please
1016 send mail to bug-gdb@prep.ai.mit.edu to let us know what changes were
1021 GDB now uses the latest `readline' library. One user-visible change
1022 is that two tabs will list possible command completions, which previously
1023 required typing M-? (meta-question mark, or ESC ?).
1027 The `stepi' bug that many of you noticed has been squashed.
1028 Many bugs in C++ have been handled. Many more remain to be handled.
1029 See the various ChangeLog files (primarily in gdb and bfd) for details.
1031 * State of the MIPS world (in case you wondered):
1033 GDB can understand the symbol tables emitted by the compilers
1034 supplied by most vendors of MIPS-based machines, including DEC. These
1035 symbol tables are in a format that essentially nobody else uses.
1037 Some versions of gcc come with an assembler post-processor called
1038 mips-tfile. This program is required if you want to do source-level
1039 debugging of gcc-compiled programs. I believe FSF does not ship
1040 mips-tfile with gcc version 1, but it will eventually come with gcc
1043 Debugging of g++ output remains a problem. g++ version 1.xx does not
1044 really support it at all. (If you're lucky, you should be able to get
1045 line numbers and stack traces to work, but no parameters or local
1046 variables.) With some work it should be possible to improve the
1049 When gcc version 2 is released, you will have somewhat better luck.
1050 However, even then you will get confusing results for inheritance and
1053 We will eventually provide full debugging of g++ output on
1054 DECstations. This will probably involve some kind of stabs-in-ecoff
1055 encapulation, but the details have not been worked out yet.
1058 *** Changes in GDB-4.2:
1060 * Improved configuration
1062 Only one copy of `configure' exists now, and it is not self-modifying.
1063 Porting BFD is simpler.
1067 The `step' and `next' commands now only stop at the first instruction
1068 of a source line. This prevents the multiple stops that used to occur
1069 in switch statements, for-loops, etc. `Step' continues to stop if a
1070 function that has debugging information is called within the line.
1074 Lots of small bugs fixed. More remain.
1076 * New host supported (not target)
1078 Intel 386 PC clone running Mach i386-none-mach
1081 *** Changes in GDB-4.1:
1083 * Multiple source language support
1085 GDB now has internal scaffolding to handle several source languages.
1086 It determines the type of each source file from its filename extension,
1087 and will switch expression parsing and number formatting to match the
1088 language of the function in the currently selected stack frame.
1089 You can also specifically set the language to be used, with
1090 `set language c' or `set language modula-2'.
1094 GDB now has preliminary support for the GNU Modula-2 compiler,
1095 currently under development at the State University of New York at
1096 Buffalo. Development of both GDB and the GNU Modula-2 compiler will
1097 continue through the fall of 1991 and into 1992.
1099 Other Modula-2 compilers are currently not supported, and attempting to
1100 debug programs compiled with them will likely result in an error as the
1101 symbol table is read. Feel free to work on it, though!
1103 There are hooks in GDB for strict type checking and range checking,
1104 in the `Modula-2 philosophy', but they do not currently work.
1108 GDB can now write to executable and core files (e.g. patch
1109 a variable's value). You must turn this switch on, specify
1110 the file ("exec foo" or "core foo"), *then* modify it, e.g.
1111 by assigning a new value to a variable. Modifications take
1114 * Automatic SunOS shared library reading
1116 When you run your program, GDB automatically determines where its
1117 shared libraries (if any) have been loaded, and reads their symbols.
1118 The `share' command is no longer needed. This also works when
1119 examining core files.
1123 You can specify the number of lines that the `list' command shows.
1126 * New machines supported (host and target)
1128 SGI Iris (MIPS) running Irix V3: mips-sgi-irix or iris
1129 Sony NEWS (68K) running NEWSOS 3.x: m68k-sony-sysv or news
1130 Ultracomputer (29K) running Sym1: a29k-nyu-sym1 or ultra3
1132 * New hosts supported (not targets)
1134 IBM RT/PC: romp-ibm-aix or rtpc
1136 * New targets supported (not hosts)
1138 AMD 29000 embedded with COFF a29k-none-coff
1139 AMD 29000 embedded with a.out a29k-none-aout
1140 Ultracomputer remote kernel debug a29k-nyu-kern
1142 * New remote interfaces
1148 *** Changes in GDB-4.0:
1152 Wide output is wrapped at good places to make the output more readable.
1154 Gdb now supports cross-debugging from a host machine of one type to a
1155 target machine of another type. Communication with the target system
1156 is over serial lines. The ``target'' command handles connecting to the
1157 remote system; the ``load'' command will download a program into the
1158 remote system. Serial stubs for the m68k and i386 are provided. Gdb
1159 also supports debugging of realtime processes running under VxWorks,
1160 using SunRPC Remote Procedure Calls over TCP/IP to talk to a debugger
1161 stub on the target system.
1163 New CPUs supported include the AMD 29000 and Intel 960.
1165 GDB now reads object files and symbol tables via a ``binary file''
1166 library, which allows a single copy of GDB to debug programs of multiple
1167 object file types such as a.out and coff.
1169 There is now a GDB reference card in "doc/refcard.tex". (Make targets
1170 refcard.dvi and refcard.ps are available to format it).
1173 * Control-Variable user interface simplified
1175 All variables that control the operation of the debugger can be set
1176 by the ``set'' command, and displayed by the ``show'' command.
1178 For example, ``set prompt new-gdb=>'' will change your prompt to new-gdb=>.
1179 ``Show prompt'' produces the response:
1180 Gdb's prompt is new-gdb=>.
1182 What follows are the NEW set commands. The command ``help set'' will
1183 print a complete list of old and new set commands. ``help set FOO''
1184 will give a longer description of the variable FOO. ``show'' will show
1185 all of the variable descriptions and their current settings.
1187 confirm on/off: Enables warning questions for operations that are
1188 hard to recover from, e.g. rerunning the program while
1189 it is already running. Default is ON.
1191 editing on/off: Enables EMACS style command line editing
1192 of input. Previous lines can be recalled with
1193 control-P, the current line can be edited with control-B,
1194 you can search for commands with control-R, etc.
1197 history filename NAME: NAME is where the gdb command history
1198 will be stored. The default is .gdb_history,
1199 or the value of the environment variable
1202 history size N: The size, in commands, of the command history. The
1203 default is 256, or the value of the environment variable
1206 history save on/off: If this value is set to ON, the history file will
1207 be saved after exiting gdb. If set to OFF, the
1208 file will not be saved. The default is OFF.
1210 history expansion on/off: If this value is set to ON, then csh-like
1211 history expansion will be performed on
1212 command line input. The default is OFF.
1214 radix N: Sets the default radix for input and output. It can be set
1215 to 8, 10, or 16. Note that the argument to "radix" is interpreted
1216 in the current radix, so "set radix 10" is always a no-op.
1218 height N: This integer value is the number of lines on a page. Default
1219 is 24, the current `stty rows'' setting, or the ``li#''
1220 setting from the termcap entry matching the environment
1223 width N: This integer value is the number of characters on a line.
1224 Default is 80, the current `stty cols'' setting, or the ``co#''
1225 setting from the termcap entry matching the environment
1228 Note: ``set screensize'' is obsolete. Use ``set height'' and
1229 ``set width'' instead.
1231 print address on/off: Print memory addresses in various command displays,
1232 such as stack traces and structure values. Gdb looks
1233 more ``symbolic'' if you turn this off; it looks more
1234 ``machine level'' with it on. Default is ON.
1236 print array on/off: Prettyprint arrays. New convenient format! Default
1239 print demangle on/off: Print C++ symbols in "source" form if on,
1242 print asm-demangle on/off: Same, for assembler level printouts
1245 print vtbl on/off: Prettyprint C++ virtual function tables. Default is OFF.
1248 * Support for Epoch Environment.
1250 The epoch environment is a version of Emacs v18 with windowing. One
1251 new command, ``inspect'', is identical to ``print'', except that if you
1252 are running in the epoch environment, the value is printed in its own
1256 * Support for Shared Libraries
1258 GDB can now debug programs and core files that use SunOS shared libraries.
1259 Symbols from a shared library cannot be referenced
1260 before the shared library has been linked with the program (this
1261 happens after you type ``run'' and before the function main() is entered).
1262 At any time after this linking (including when examining core files
1263 from dynamically linked programs), gdb reads the symbols from each
1264 shared library when you type the ``sharedlibrary'' command.
1265 It can be abbreviated ``share''.
1267 sharedlibrary REGEXP: Load shared object library symbols for files
1268 matching a unix regular expression. No argument
1269 indicates to load symbols for all shared libraries.
1271 info sharedlibrary: Status of loaded shared libraries.
1276 A watchpoint stops execution of a program whenever the value of an
1277 expression changes. Checking for this slows down execution
1278 tremendously whenever you are in the scope of the expression, but is
1279 quite useful for catching tough ``bit-spreader'' or pointer misuse
1280 problems. Some machines such as the 386 have hardware for doing this
1281 more quickly, and future versions of gdb will use this hardware.
1283 watch EXP: Set a watchpoint (breakpoint) for an expression.
1285 info watchpoints: Information about your watchpoints.
1287 delete N: Deletes watchpoint number N (same as breakpoints).
1288 disable N: Temporarily turns off watchpoint number N (same as breakpoints).
1289 enable N: Re-enables watchpoint number N (same as breakpoints).
1292 * C++ multiple inheritance
1294 When used with a GCC version 2 compiler, GDB supports multiple inheritance
1297 * C++ exception handling
1299 Gdb now supports limited C++ exception handling. Besides the existing
1300 ability to breakpoint on an exception handler, gdb can breakpoint on
1301 the raising of an exception (before the stack is peeled back to the
1304 catch FOO: If there is a FOO exception handler in the dynamic scope,
1305 set a breakpoint to catch exceptions which may be raised there.
1306 Multiple exceptions (``catch foo bar baz'') may be caught.
1308 info catch: Lists all exceptions which may be caught in the
1309 current stack frame.
1312 * Minor command changes
1314 The command ``call func (arg, arg, ...)'' now acts like the print
1315 command, except it does not print or save a value if the function's result
1316 is void. This is similar to dbx usage.
1318 The ``up'' and ``down'' commands now always print the frame they end up
1319 at; ``up-silently'' and `down-silently'' can be used in scripts to change
1320 frames without printing.
1322 * New directory command
1324 'dir' now adds directories to the FRONT of the source search path.
1325 The path starts off empty. Source files that contain debug information
1326 about the directory in which they were compiled can be found even
1327 with an empty path; Sun CC and GCC include this information. If GDB can't
1328 find your source file in the current directory, type "dir .".
1330 * Configuring GDB for compilation
1332 For normal use, type ``./configure host''. See README or gdb.texinfo
1335 GDB now handles cross debugging. If you are remotely debugging between
1336 two different machines, type ``./configure host -target=targ''.
1337 Host is the machine where GDB will run; targ is the machine
1338 where the program that you are debugging will run.