1 What has changed since GDB-3.5?
2 (Organized release by release)
4 *** Changes in GDB-4.6:
6 * Better support for C++ function names
8 GDB now accepts as input the "demangled form" of C++ overloaded function
9 names and member function names, and can do command completion on such names
10 (using TAB, TAB-TAB, and ESC-?). The names have to be quoted with a pair of
11 single quotes. Examples are 'func (int, long)' and 'obj::operator==(obj&)'.
12 Make use of command completion, it is your friend.
14 GDB also now accepts a variety of C++ mangled symbol formats. They are
15 the GNU g++ style, the Cfront (ARM) style, and the Lucid (lcc) style.
16 You can tell GDB which format to use by doing a 'set demangle-style {gnu,
17 lucid, cfront, auto}'. 'gnu' is the default. Do a 'set demangle-style foo'
18 for the list of formats.
20 * G++ symbol mangling problem
22 Recent versions of gcc have a bug in how they emit debugging information for
23 C++ methods (when using dbx-style stabs). The file 'gcc.patch' (in this
24 directory) can be applied to gcc to fix the problem. Alternatively, if you
25 can't fix gcc, you can #define GCC_MANGLE_BUG when compling gdb/symtab.c. The
26 usual symptom is difficulty with setting breakpoints on methods. GDB complains
27 about the method being non-existent. (We believe that version 2.2.2 of GCC has
30 * New 'maintenance' command
32 All of the commands related to hacking GDB internals have been moved out of
33 the main command set, and now live behind the 'maintenance' command. This
34 can also be abbreviated as 'mt'. The following changes were made:
36 dump-me -> maintenance dump-me
37 info all-breakpoints -> maintenance info breakpoints
38 printmsyms -> maintenance print msyms
39 printobjfiles -> maintenance print objfiles
40 printpsyms -> maintenance print psymbols
41 printsyms -> maintenance print symbols
43 The following commands are new:
45 maintenance demangle Call internal GDB demangler routine to
46 demangle a C++ link name and prints the result.
47 maintenance print type Print a type chain for a given symbol
49 * Change to .gdbinit file processing
51 We now read the $HOME/.gdbinit file before processing the argv arguments
52 (e.g. reading symbol files or core files). This allows global parameters to
53 be set, which will apply during the symbol reading. The ./.gdbinit is still
54 read after argv processing.
58 Solaris-2.0 !!! sparc-sun-solaris2 or sun4sol2
60 Linux support i386-unknown-linux or linux
62 We are also including code to support the HP/PA running BSD and HPUX. This
63 is almost guaranteed not to work, as we didn't have time to test or build it
64 for this release. We are including it so that the more adventurous (or
65 masochistic) of you can play with it. We also had major problems with the
66 fact that the compiler that we got from HP doesn't support the -g option.
69 * New targets supported
71 Hitachi H8/300 h8300-hitachi-hms or h8300hms
73 * More smarts about finding #include files
75 GDB now remembers the compilation directory for all include files, and for
76 all files from which C is generated (like yacc and lex sources). This
77 greatly improves GDB's ability to find yacc/lex sources, and include files,
78 especially if you are debugging your program from a directory different from
79 the one that contains your sources.
81 We also fixed a bug which caused difficulty with listing and setting
82 breakpoints in include files which contain C code. (In the past, you had to
83 try twice in order to list an include file that you hadn't looked at before.)
85 * Interesting infernals change
87 GDB now deals with arbitrary numbers of sections, where the symbols for each
88 section must be relocated relative to that section's landing place in the
89 target's address space. This work was needed to support ELF with embedded
90 stabs used by Solaris-2.0.
92 * Bug fixes (of course!)
94 There have been loads of fixes for the following things:
95 mips, rs6000, 29k/udi, m68k, g++, type handling, elf/dwarf, m88k,
96 i960, stabs, DOS(GO32), procfs, etc...
98 See the ChangeLog for details.
100 *** Changes in GDB-4.5:
102 * New machines supported (host and target)
104 IBM RS6000 running AIX rs6000-ibm-aix or rs6000
106 SGI Irix-4.x mips-sgi-irix4 or iris4
110 GDB now uses a new memory manager called mmalloc, based on gmalloc.
111 Mmalloc is capable of handling mutiple heaps of memory. It is also
112 capable of saving a heap to a file, and then mapping it back in later.
113 This can be used to greatly speedup the startup of GDB by using a
114 pre-parsed symbol table which lives in a mmalloc managed heap. For
115 more details, please read mmalloc/mmalloc.texi.
119 The 'info proc' command (SVR4 only) has been enhanced quite a bit. See
120 'help info proc' for details.
122 * MIPS ecoff symbol table format
124 The code that reads MIPS symbol table format is now supported on all hosts.
125 Thanks to MIPS for releasing the sym.h and symconst.h files to make this
128 * File name changes for MS-DOS
130 Many files in the config directories have been renamed to make it easier to
131 support GDB on MS-DOSe systems (which have very restrictive file name
132 conventions :-( ). MS-DOSe host support (under DJ Delorie's GO32
133 environment) is close to working but has some remaining problems. Note
134 that debugging of DOS programs is not supported, due to limitations
135 in the ``operating system'', but it can be used to host cross-debugging.
137 * Cross byte order fixes
139 Many fixes have been made to support cross debugging of Sparc and MIPS
140 targets from hosts whose byte order differs.
142 * New -mapped and -readnow options
144 If memory-mapped files are available on your system through the 'mmap'
145 system call, you can use the -mapped option on the `file' or
146 `symbol-file' commands to cause GDB to write the symbols from your
147 program into a reusable file. If the program you are debugging is
148 called `/path/fred', the mapped symbol file will be `./fred.syms'.
149 Future GDB debugging sessions will notice the presence of this file,
150 and will quickly map in symbol information from it, rather than reading
151 the symbol table from the executable program. Using the '-mapped'
152 option in a GDB `file' or `symbol-file' command has the same effect as
153 starting GDB with the '-mapped' command-line option.
155 You can cause GDB to read the entire symbol table immediately by using
156 the '-readnow' option with any of the commands that load symbol table
157 information (or on the GDB command line). This makes the command
158 slower, but makes future operations faster.
160 The -mapped and -readnow options are typically combined in order to
161 build a `fred.syms' file that contains complete symbol information.
162 A simple GDB invocation to do nothing but build a `.syms' file for future
165 gdb -batch -nx -mapped -readnow programname
167 The `.syms' file is specific to the host machine on which GDB is run.
168 It holds an exact image of GDB's internal symbol table. It cannot be
169 shared across multiple host platforms.
173 GDB is now capable of stepping and nexting over longjmp(), _longjmp(), and
174 siglongjmp() without losing control. This feature has not yet been ported to
175 all systems. It currently works on many 386 platforms, all MIPS-based
176 platforms (SGI, DECstation, etc), and Sun3/4.
180 Preliminary work has been put in to support the new Solaris OS from Sun. At
181 this time, it can control and debug processes, but it is not capable of
186 As always, many many bug fixes. The major areas were with g++, and mipsread.
187 People using the MIPS-based platforms should experience fewer mysterious
188 crashes and trashed symbol tables.
190 *** Changes in GDB-4.4:
192 * New machines supported (host and target)
194 SCO Unix on i386 IBM PC clones i386-sco-sysv or i386sco
196 BSD Reno on Vax vax-dec-bsd
197 Ultrix on Vax vax-dec-ultrix
199 * New machines supported (target)
201 AMD 29000 embedded, using EBMON a29k-none-none
205 GDB continues to improve its handling of C++. `References' work better.
206 The demangler has also been improved, and now deals with symbols mangled as
207 per the Annotated C++ Reference Guide.
209 GDB also now handles `stabs' symbol information embedded in MIPS
210 `ecoff' symbol tables. Since the ecoff format was not easily
211 extensible to handle new languages such as C++, this appeared to be a
212 good way to put C++ debugging info into MIPS binaries. This option
213 will be supported in the GNU C compiler, version 2, when it is
216 * New features for SVR4
218 GDB now handles SVR4 shared libraries, in the same fashion as SunOS
219 shared libraries. Debugging dynamically linked programs should present
220 only minor differences from debugging statically linked programs.
222 The `info proc' command will print out information about any process
223 on an SVR4 system (including the one you are debugging). At the moment,
224 it prints the address mappings of the process.
226 If you bring up GDB on another SVR4 system, please send mail to
227 bug-gdb@prep.ai.mit.edu to let us know what changes were reqired (if any).
229 * Better dynamic linking support in SunOS
231 Reading symbols from shared libraries which contain debugging symbols
232 now works properly. However, there remain issues such as automatic
233 skipping of `transfer vector' code during function calls, which
234 make it harder to debug code in a shared library, than to debug the
235 same code linked statically.
239 GDB is now using the latest `getopt' routines from the FSF. This
240 version accepts the -- prefix for options with long names. GDB will
241 continue to accept the old forms (-option and +option) as well.
242 Various single letter abbreviations for options have been explicity
243 added to the option table so that they won't get overshadowed in the
244 future by other options that begin with the same letter.
248 The `cleanup_undefined_types' bug that many of you noticed has been squashed.
249 Many assorted bugs have been handled. Many more remain to be handled.
250 See the various ChangeLog files (primarily in gdb and bfd) for details.
253 *** Changes in GDB-4.3:
255 * New machines supported (host and target)
257 Amiga 3000 running Amix m68k-cbm-svr4 or amix
258 NCR 3000 386 running SVR4 i386-ncr-svr4 or ncr3000
259 Motorola Delta 88000 running Sys V m88k-motorola-sysv or delta88
261 * Almost SCO Unix support
263 We had hoped to support:
264 SCO Unix on i386 IBM PC clones i386-sco-sysv or i386sco
265 (except for core file support), but we discovered very late in the release
266 that it has problems with process groups that render gdb unusable. Sorry
267 about that. I encourage people to fix it and post the fixes.
269 * Preliminary ELF and DWARF support
271 GDB can read ELF object files on System V Release 4, and can handle
272 debugging records for C, in DWARF format, in ELF files. This support
273 is preliminary. If you bring up GDB on another SVR4 system, please
274 send mail to bug-gdb@prep.ai.mit.edu to let us know what changes were
279 GDB now uses the latest `readline' library. One user-visible change
280 is that two tabs will list possible command completions, which previously
281 required typing M-? (meta-question mark, or ESC ?).
285 The `stepi' bug that many of you noticed has been squashed.
286 Many bugs in C++ have been handled. Many more remain to be handled.
287 See the various ChangeLog files (primarily in gdb and bfd) for details.
289 * State of the MIPS world (in case you wondered):
291 GDB can understand the symbol tables emitted by the compilers
292 supplied by most vendors of MIPS-based machines, including DEC. These
293 symbol tables are in a format that essentially nobody else uses.
295 Some versions of gcc come with an assembler post-processor called
296 mips-tfile. This program is required if you want to do source-level
297 debugging of gcc-compiled programs. I believe FSF does not ship
298 mips-tfile with gcc version 1, but it will eventually come with gcc
301 Debugging of g++ output remains a problem. g++ version 1.xx does not
302 really support it at all. (If you're lucky, you should be able to get
303 line numbers and stack traces to work, but no parameters or local
304 variables.) With some work it should be possible to improve the
307 When gcc version 2 is released, you will have somewhat better luck.
308 However, even then you will get confusing results for inheritance and
311 We will eventually provide full debugging of g++ output on
312 DECstations. This will probably involve some kind of stabs-in-ecoff
313 encapulation, but the details have not been worked out yet.
316 *** Changes in GDB-4.2:
318 * Improved configuration
320 Only one copy of `configure' exists now, and it is not self-modifying.
321 Porting BFD is simpler.
325 The `step' and `next' commands now only stop at the first instruction
326 of a source line. This prevents the multiple stops that used to occur
327 in switch statements, for-loops, etc. `Step' continues to stop if a
328 function that has debugging information is called within the line.
332 Lots of small bugs fixed. More remain.
334 * New host supported (not target)
336 Intel 386 PC clone running Mach i386-none-mach
339 *** Changes in GDB-4.1:
341 * Multiple source language support
343 GDB now has internal scaffolding to handle several source languages.
344 It determines the type of each source file from its filename extension,
345 and will switch expression parsing and number formatting to match the
346 language of the function in the currently selected stack frame.
347 You can also specifically set the language to be used, with
348 `set language c' or `set language modula-2'.
352 GDB now has preliminary support for the GNU Modula-2 compiler,
353 currently under development at the State University of New York at
354 Buffalo. Development of both GDB and the GNU Modula-2 compiler will
355 continue through the fall of 1991 and into 1992.
357 Other Modula-2 compilers are currently not supported, and attempting to
358 debug programs compiled with them will likely result in an error as the
359 symbol table is read. Feel free to work on it, though!
361 There are hooks in GDB for strict type checking and range checking,
362 in the `Modula-2 philosophy', but they do not currently work.
366 GDB can now write to executable and core files (e.g. patch
367 a variable's value). You must turn this switch on, specify
368 the file ("exec foo" or "core foo"), *then* modify it, e.g.
369 by assigning a new value to a variable. Modifications take
372 * Automatic SunOS shared library reading
374 When you run your program, GDB automatically determines where its
375 shared libraries (if any) have been loaded, and reads their symbols.
376 The `share' command is no longer needed. This also works when
377 examining core files.
381 You can specify the number of lines that the `list' command shows.
384 * New machines supported (host and target)
386 SGI Iris (MIPS) running Irix V3: mips-sgi-irix or iris
387 Sony NEWS (68K) running NEWSOS 3.x: m68k-sony-sysv or news
388 Ultracomputer (29K) running Sym1: a29k-nyu-sym1 or ultra3
390 * New hosts supported (not targets)
392 IBM RT/PC: romp-ibm-aix or rtpc
394 * New targets supported (not hosts)
396 AMD 29000 embedded with COFF a29k-none-coff
397 AMD 29000 embedded with a.out a29k-none-aout
398 Ultracomputer remote kernel debug a29k-nyu-kern
400 * New remote interfaces
406 *** Changes in GDB-4.0:
410 Wide output is wrapped at good places to make the output more readable.
412 Gdb now supports cross-debugging from a host machine of one type to a
413 target machine of another type. Communication with the target system
414 is over serial lines. The ``target'' command handles connecting to the
415 remote system; the ``load'' command will download a program into the
416 remote system. Serial stubs for the m68k and i386 are provided. Gdb
417 also supports debugging of realtime processes running under VxWorks,
418 using SunRPC Remote Procedure Calls over TCP/IP to talk to a debugger
419 stub on the target system.
421 New CPUs supported include the AMD 29000 and Intel 960.
423 GDB now reads object files and symbol tables via a ``binary file''
424 library, which allows a single copy of GDB to debug programs of multiple
425 object file types such as a.out and coff.
427 There is now a GDB reference card in "doc/refcard.tex". (Make targets
428 refcard.dvi and refcard.ps are available to format it).
431 * Control-Variable user interface simplified
433 All variables that control the operation of the debugger can be set
434 by the ``set'' command, and displayed by the ``show'' command.
436 For example, ``set prompt new-gdb=>'' will change your prompt to new-gdb=>.
437 ``Show prompt'' produces the response:
438 Gdb's prompt is new-gdb=>.
440 What follows are the NEW set commands. The command ``help set'' will
441 print a complete list of old and new set commands. ``help set FOO''
442 will give a longer description of the variable FOO. ``show'' will show
443 all of the variable descriptions and their current settings.
445 confirm on/off: Enables warning questions for operations that are
446 hard to recover from, e.g. rerunning the program while
447 it is already running. Default is ON.
449 editing on/off: Enables EMACS style command line editing
450 of input. Previous lines can be recalled with
451 control-P, the current line can be edited with control-B,
452 you can search for commands with control-R, etc.
455 history filename NAME: NAME is where the gdb command history
456 will be stored. The default is .gdb_history,
457 or the value of the environment variable
460 history size N: The size, in commands, of the command history. The
461 default is 256, or the value of the environment variable
464 history save on/off: If this value is set to ON, the history file will
465 be saved after exiting gdb. If set to OFF, the
466 file will not be saved. The default is OFF.
468 history expansion on/off: If this value is set to ON, then csh-like
469 history expansion will be performed on
470 command line input. The default is OFF.
472 radix N: Sets the default radix for input and output. It can be set
473 to 8, 10, or 16. Note that the argument to "radix" is interpreted
474 in the current radix, so "set radix 10" is always a no-op.
476 height N: This integer value is the number of lines on a page. Default
477 is 24, the current `stty rows'' setting, or the ``li#''
478 setting from the termcap entry matching the environment
481 width N: This integer value is the number of characters on a line.
482 Default is 80, the current `stty cols'' setting, or the ``co#''
483 setting from the termcap entry matching the environment
486 Note: ``set screensize'' is obsolete. Use ``set height'' and
487 ``set width'' instead.
489 print address on/off: Print memory addresses in various command displays,
490 such as stack traces and structure values. Gdb looks
491 more ``symbolic'' if you turn this off; it looks more
492 ``machine level'' with it on. Default is ON.
494 print array on/off: Prettyprint arrays. New convenient format! Default
497 print demangle on/off: Print C++ symbols in "source" form if on,
500 print asm-demangle on/off: Same, for assembler level printouts
503 print vtbl on/off: Prettyprint C++ virtual function tables. Default is OFF.
506 * Support for Epoch Environment.
508 The epoch environment is a version of Emacs v18 with windowing. One
509 new command, ``inspect'', is identical to ``print'', except that if you
510 are running in the epoch environment, the value is printed in its own
514 * Support for Shared Libraries
516 GDB can now debug programs and core files that use SunOS shared libraries.
517 Symbols from a shared library cannot be referenced
518 before the shared library has been linked with the program (this
519 happens after you type ``run'' and before the function main() is entered).
520 At any time after this linking (including when examining core files
521 from dynamically linked programs), gdb reads the symbols from each
522 shared library when you type the ``sharedlibrary'' command.
523 It can be abbreviated ``share''.
525 sharedlibrary REGEXP: Load shared object library symbols for files
526 matching a unix regular expression. No argument
527 indicates to load symbols for all shared libraries.
529 info sharedlibrary: Status of loaded shared libraries.
534 A watchpoint stops execution of a program whenever the value of an
535 expression changes. Checking for this slows down execution
536 tremendously whenever you are in the scope of the expression, but is
537 quite useful for catching tough ``bit-spreader'' or pointer misuse
538 problems. Some machines such as the 386 have hardware for doing this
539 more quickly, and future versions of gdb will use this hardware.
541 watch EXP: Set a watchpoint (breakpoint) for an expression.
543 info watchpoints: Information about your watchpoints.
545 delete N: Deletes watchpoint number N (same as breakpoints).
546 disable N: Temporarily turns off watchpoint number N (same as breakpoints).
547 enable N: Re-enables watchpoint number N (same as breakpoints).
550 * C++ multiple inheritance
552 When used with a GCC version 2 compiler, GDB supports multiple inheritance
555 * C++ exception handling
557 Gdb now supports limited C++ exception handling. Besides the existing
558 ability to breakpoint on an exception handler, gdb can breakpoint on
559 the raising of an exception (before the stack is peeled back to the
562 catch FOO: If there is a FOO exception handler in the dynamic scope,
563 set a breakpoint to catch exceptions which may be raised there.
564 Multiple exceptions (``catch foo bar baz'') may be caught.
566 info catch: Lists all exceptions which may be caught in the
570 * Minor command changes
572 The command ``call func (arg, arg, ...)'' now acts like the print
573 command, except it does not print or save a value if the function's result
574 is void. This is similar to dbx usage.
576 The ``up'' and ``down'' commands now always print the frame they end up
577 at; ``up-silently'' and `down-silently'' can be used in scripts to change
578 frames without printing.
580 * New directory command
582 'dir' now adds directories to the FRONT of the source search path.
583 The path starts off empty. Source files that contain debug information
584 about the directory in which they were compiled can be found even
585 with an empty path; Sun CC and GCC include this information. If GDB can't
586 find your source file in the current directory, type "dir .".
588 * Configuring GDB for compilation
590 For normal use, type ``./configure host''. See README or gdb.texinfo
593 GDB now handles cross debugging. If you are remotely debugging between
594 two different machines, type ``./configure host -target=targ''.
595 Host is the machine where GDB will run; targ is the machine
596 where the program that you are debugging will run.
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