gdb/NEWS

   1                 What has changed since GDB-3.5?
   2                 (Organized release by release)
   3
   4 *** Changes in GDB-4.9:
   5
   6  * Testsuite
   7
   8 This is the first GDB release which is accompanied by a matching testsuite.
   9 The testsuite requires installation of dejagnu, which should be available
  10 via ftp from most sites that carry GNU software.
  11
  12  * C++ demangling
  13
  14 'Cfront' style demangling has had its name changed to 'ARM' style, to
  15 emphasize that it was written from the specifications in the C++ Annotated
  16 Reference Manual, not necessarily to be compatible with AT&T cfront.  Despite
  17 disclaimers, it still generated too much confusion with users attempting to
  18 use gdb with AT&T cfront.
  19
  20  * Simulators
  21
  22 GDB now uses a standard remote interface to a simulator library.
  23 So far, the library contains simulators for the Zilog Z8001/2, the
  24 Hitachi H8/300, H8/500 and Super-H.
  25
  26  * New targets supported
  27
  28 H8/300 simulator                        h8300-hitachi-hms or h8300hms
  29 H8/500 simulator                        h8500-hitachi-hms or h8500hms
  30 SH simulator                            sh-hitachi-hms    or sh
  31 Z8000 simulator                         z8k-zilog-none    or z8ksim
  32 IDT MIPS board over serial line         mips-idt-ecoff
  33
  34 Cross-debugging to GO32 targets is supported.  It requires a custom
  35 version of the i386-stub.c module which is integrated with the
  36 GO32 memory extender.
  37
  38  * New remote protocols
  39
  40 MIPS remote debugging protocol.
  41
  42  * New source languages supported
  43
  44 This version includes preliminary support for Chill, a Pascal like language
  45 used by telecommunications companies.  Chill support is also being integrated
  46 into the GNU compiler, but we don't know when it will be publically available.
  47
  48
  49 *** Changes in GDB-4.8:
  50
  51  * HP Precision Architecture supported
  52
  53 GDB now supports HP PA-RISC machines running HPUX.  A preliminary
  54 version of this support was available as a set of patches from the
  55 University of Utah.  GDB does not support debugging of programs
  56 compiled with the HP compiler, because HP will not document their file
  57 format.  Instead, you must use GCC (version 2.3.2 or later) and PA-GAS
  58 (as available from jaguar.cs.utah.edu:/dist/pa-gas.u4.tar.Z).
  59
  60 Many problems in the preliminary version have been fixed.
  61
  62  * Faster and better demangling
  63
  64 We have improved template demangling and fixed numerous bugs in the GNU style
  65 demangler.  It can now handle type modifiers such as `static' or `const'.  Wide
  66 character types (wchar_t) are now supported.  Demangling of each symbol is now
  67 only done once, and is cached when the symbol table for a file is read in.
  68 This results in a small increase in memory usage for C programs, a moderate
  69 increase in memory usage for C++ programs, and a fantastic speedup in
  70 symbol lookups.
  71
  72 `Cfront' style demangling still doesn't work with AT&T cfront.  It was written
  73 from the specifications in the Annotated Reference Manual, which AT&T's
  74 compiler does not actually implement.
  75
  76  * G++ multiple inheritance compiler problem
  77
  78 In the 2.3.2 release of gcc/g++, how the compiler resolves multiple
  79 inheritance lattices was reworked to properly discover ambiguities.  We
  80 recently found an example which causes this new algorithm to fail in a
  81 very subtle way, producing bad debug information for those classes.
  82 The file 'gcc.patch' (in this directory) can be applied to gcc to
  83 circumvent the problem.  A future GCC release will contain a complete
  84 fix.
  85
  86 The previous G++ debug info problem (mentioned below for the gdb-4.7
  87 release) is fixed in gcc version 2.3.2.
  88
  89  * Improved configure script
  90
  91 The `configure' script will now attempt to guess your system type if
  92 you don't supply a host system type.  The old scheme of supplying a
  93 host system triplet is preferable over using this.  All the magic is
  94 done in the new `config.guess' script.  Examine it for details.
  95
  96 We have also brought our configure script much more in line with the FSF's
  97 version.  It now supports the --with-xxx options.  In particular,
  98 `--with-minimal-bfd' can be used to make the GDB binary image smaller.
  99 The resulting GDB will not be able to read arbitrary object file formats --
 100 only the format ``expected'' to be used on the configured target system.
 101 We hope to make this the default in a future release.
 102
 103  * Documentation improvements
 104
 105 There's new internal documentation on how to modify GDB, and how to
 106 produce clean changes to the code.  We implore people to read it
 107 before submitting changes.
 108
 109 The GDB manual uses new, sexy Texinfo conditionals, rather than arcane
 110 M4 macros.  The new texinfo.tex is provided in this release.  Pre-built
 111 `info' files are also provided.  To build `info' files from scratch,
 112 you will need the latest `makeinfo' release, which will be available in
 113 a future texinfo-X.Y release.
 114
 115 *NOTE*  The new texinfo.tex can cause old versions of TeX to hang.
 116 We're not sure exactly which versions have this problem, but it has
 117 been seen in 3.0.  We highly recommend upgrading to TeX version 3.141
 118 or better.  If that isn't possible, there is a patch in
 119 `texinfo/tex3patch' that will modify `texinfo/texinfo.tex' to work
 120 around this problem.
 121
 122  * New features
 123
 124 GDB now supports array constants that can be used in expressions typed in by
 125 the user.  The syntax is `{element, element, ...}'.  Ie: you can now type
 126 `print {1, 2, 3}', and it will build up an array in memory malloc'd in
 127 the target program.
 128
 129 The new directory `gdb/sparclite' contains a program that demonstrates
 130 how the sparc-stub.c remote stub runs on a Fujitsu SPARClite processor.
 131
 132  * New native hosts supported
 133
 134 HP/PA-RISC under HPUX using GNU tools   hppa1.1-hp-hpux
 135 386 CPUs running SCO Unix 3.2v4         i386-unknown-sco3.2v4
 136
 137  * New targets supported
 138
 139 AMD 29k family via UDI                  a29k-amd-udi  or  udi29k
 140
 141  * New file formats supported
 142
 143 BFD now supports reading HP/PA-RISC executables (SOM file format?),
 144 HPUX core files, and SCO 3.2v2 core files.
 145
 146  * Major bug fixes
 147
 148 Attaching to processes now works again; thanks for the many bug reports.
 149
 150 We have also stomped on a bunch of core dumps caused by
 151 printf_filtered("%s") problems.
 152
 153 We eliminated a copyright problem on the rpc and ptrace header files
 154 for VxWorks, which was discovered at the last minute during the 4.7
 155 release.  You should now be able to build a VxWorks GDB.
 156
 157 You can now interrupt gdb while an attached process is running.  This
 158 will cause the attached process to stop, and give control back to GDB.
 159
 160 We fixed problems caused by using too many file descriptors
 161 for reading symbols from object files and libraries.  This was
 162 especially a problem for programs that used many (~100) shared
 163 libraries.
 164
 165 The `step' command now only enters a subroutine if there is line number
 166 information for the subroutine.  Otherwise it acts like the `next'
 167 command.  Previously, `step' would enter subroutines if there was
 168 any debugging information about the routine.  This avoids problems
 169 when using `cc -g1' on MIPS machines.
 170
 171  * Internal improvements
 172
 173 GDB's internal interfaces have been improved to make it easier to support
 174 debugging of multiple languages in the future.
 175
 176 GDB now uses a common structure for symbol information internally.
 177 Minimal symbols (derived from linkage symbols in object files), partial
 178 symbols (from a quick scan of debug information), and full symbols
 179 contain a common subset of information, making it easier to write
 180 shared code that handles any of them.
 181
 182  * New command line options
 183
 184 We now accept --silent as an alias for --quiet.
 185
 186  * Mmalloc licensing
 187
 188 The memory-mapped-malloc library is now licensed under the GNU Library
 189 General Public License.
 190
 191 *** Changes in GDB-4.7:
 192
 193  * Host/native/target split
 194
 195 GDB has had some major internal surgery to untangle the support for
 196 hosts and remote targets.  Now, when you configure GDB for a remote
 197 target, it will no longer load in all of the support for debugging
 198 local programs on the host.  When fully completed and tested, this will
 199 ensure that arbitrary host/target combinations are possible.
 200
 201 The primary conceptual shift is to separate the non-portable code in
 202 GDB into three categories.  Host specific code is required any time GDB
 203 is compiled on that host, regardless of the target.  Target specific
 204 code relates to the peculiarities of the target, but can be compiled on
 205 any host.  Native specific code is everything else:  it can only be
 206 built when the host and target are the same system.  Child process
 207 handling and core file support are two common `native' examples.
 208
 209 GDB's use of /proc for controlling Unix child processes is now cleaner.
 210 It has been split out into a single module under the `target_ops' vector,
 211 plus two native-dependent functions for each system that uses /proc.
 212
 213  * New hosts supported
 214
 215 HP/Apollo 68k (under the BSD domain)    m68k-apollo-bsd  or  apollo68bsd
 216 386 CPUs running various BSD ports      i386-unknown-bsd  or  386bsd
 217 386 CPUs running SCO Unix               i386-unknown-scosysv322  or  i386sco
 218
 219  * New targets supported
 220
 221 Fujitsu SPARClite                       sparclite-fujitsu-none  or  sparclite
 222 68030 and CPU32                         m68030-*-*, m68332-*-*
 223
 224  * New native hosts supported
 225
 226 386 CPUs running various BSD ports      i386-unknown-bsd  or  386bsd
 227     (386bsd is not well tested yet)
 228 386 CPUs running SCO Unix               i386-unknown-scosysv322  or  sco
 229
 230  * New file formats supported
 231
 232 BFD now supports COFF files for the Zilog Z8000 microprocessor.  It
 233 supports reading of `a.out.adobe' object files, which are an a.out
 234 format extended with minimal information about multiple sections.
 235
 236  * New commands
 237
 238 `show copying' is the same as the old `info copying'.
 239 `show warranty' is the same as `info warrantee'.
 240 These were renamed for consistency.  The old commands continue to work.
 241
 242 `info handle' is a new alias for `info signals'.
 243
 244 You can now define pre-command hooks, which attach arbitrary command
 245 scripts to any command.  The commands in the hook will be executed
 246 prior to the user's command.  You can also create a hook which will be
 247 executed whenever the program stops.  See gdb.texinfo.
 248
 249  * C++ improvements
 250
 251 We now deal with Cfront style name mangling, and can even extract type
 252 info from mangled symbols.  GDB can automatically figure out which
 253 symbol mangling style your C++ compiler uses.
 254
 255 Calling of methods and virtual functions has been improved as well.
 256
 257  * Major bug fixes
 258
 259 The crash that occured when debugging Sun Ansi-C compiled binaries is
 260 fixed.  This was due to mishandling of the extra N_SO stabs output
 261 by the compiler.
 262
 263 We also finally got Ultrix 4.2 running in house, and fixed core file
 264 support, with help from a dozen people on the net.
 265
 266 John M. Farrell discovered that the reason that single-stepping was so
 267 slow on all of the Mips based platforms (primarily SGI and DEC) was
 268 that we were trying to demangle and lookup a symbol used for internal
 269 purposes on every instruction that was being stepped through.  Changing
 270 the name of that symbol so that it couldn't be mistaken for a C++
 271 mangled symbol sped things up a great deal.
 272
 273 Rich Pixley sped up symbol lookups in general by getting much smarter
 274 about when C++ symbol mangling is necessary.  This should make symbol
 275 completion (TAB on the command line) much faster.  It's not as fast as
 276 we'd like, but it's significantly faster than gdb-4.6.
 277
 278  * AMD 29k support
 279
 280 A new user controllable variable 'call_scratch_address' can
 281 specify the location of a scratch area to be used when GDB
 282 calls a function in the target.  This is necessary because the
 283 usual method of putting the scratch area on the stack does not work
 284 in systems that have separate instruction and data spaces.
 285
 286 We integrated changes to support the 29k UDI (Universal Debugger
 287 Interface), but discovered at the last minute that we didn't have all
 288 of the appropriate copyright paperwork.  We are working with AMD to
 289 resolve this, and hope to have it available soon.
 290
 291  * Remote interfaces
 292
 293 We have sped up the remote serial line protocol, especially for targets
 294 with lots of registers.  It now supports a new `expedited status' ('T')
 295 message which can be used in place of the existing 'S' status message.
 296 This allows the remote stub to send only the registers that GDB
 297 needs to make a quick decision about single-stepping or conditional
 298 breakpoints, eliminating the need to fetch the entire register set for
 299 each instruction being stepped through.
 300
 301 The GDB remote serial protocol now implements a write-through cache for
 302 registers, only re-reading the registers if the target has run.
 303
 304 There is also a new remote serial stub for SPARC processors.  You can
 305 find it in gdb-4.7/gdb/sparc-stub.c.  This was written to support the
 306 Fujitsu SPARClite processor, but will run on any stand-alone SPARC
 307 processor with a serial port.
 308
 309  * Configuration
 310
 311 Configure.in files have become much easier to read and modify.  A new
 312 `table driven' format makes it more obvious what configurations are
 313 supported, and what files each one uses.
 314
 315  * Library changes
 316
 317 There is a new opcodes library which will eventually contain all of the
 318 disassembly routines and opcode tables.  At present, it only contains
 319 Sparc and Z8000 routines.  This will allow the assembler, debugger, and
 320 disassembler (binutils/objdump) to share these routines.
 321
 322 The libiberty library is now copylefted under the GNU Library General
 323 Public License.  This allows more liberal use, and was done so libg++
 324 can use it.  This makes no difference to GDB, since the Library License
 325 grants all the rights from the General Public License.
 326
 327  * Documentation
 328
 329 The file gdb-4.7/gdb/doc/stabs.texinfo is a (relatively) complete
 330 reference to the stabs symbol info used by the debugger.  It is (as far
 331 as we know) the only published document on this fascinating topic.  We
 332 encourage you to read it, compare it to the stabs information on your
 333 system, and send improvements on the document in general (to
 334 bug-gdb@prep.ai.mit.edu).
 335
 336 And, of course, many bugs have been fixed.
 337
 338
 339 *** Changes in GDB-4.6:
 340
 341  * Better support for C++ function names
 342
 343 GDB now accepts as input the "demangled form" of C++ overloaded function
 344 names and member function names, and can do command completion on such names
 345 (using TAB, TAB-TAB, and ESC-?).  The names have to be quoted with a pair of
 346 single quotes.  Examples are 'func (int, long)' and 'obj::operator==(obj&)'.
 347 Make use of command completion, it is your friend.
 348
 349 GDB also now accepts a variety of C++ mangled symbol formats.  They are
 350 the GNU g++ style, the Cfront (ARM) style, and the Lucid (lcc) style.
 351 You can tell GDB which format to use by doing a 'set demangle-style {gnu,
 352 lucid, cfront, auto}'.  'gnu' is the default.  Do a 'set demangle-style foo'
 353 for the list of formats.
 354
 355  * G++ symbol mangling problem
 356
 357 Recent versions of gcc have a bug in how they emit debugging information for
 358 C++ methods (when using dbx-style stabs).  The file 'gcc.patch' (in this
 359 directory) can be applied to gcc to fix the problem.  Alternatively, if you
 360 can't fix gcc, you can #define GCC_MANGLE_BUG when compling gdb/symtab.c. The
 361 usual symptom is difficulty with setting breakpoints on methods.  GDB complains
 362 about the method being non-existent.  (We believe that version 2.2.2 of GCC has
 363 this problem.)
 364
 365  * New 'maintenance' command
 366
 367 All of the commands related to hacking GDB internals have been moved out of
 368 the main command set, and now live behind the 'maintenance' command.  This
 369 can also be abbreviated as 'mt'.  The following changes were made:
 370
 371         dump-me ->              maintenance dump-me
 372         info all-breakpoints -> maintenance info breakpoints
 373         printmsyms ->           maintenance print msyms
 374         printobjfiles ->        maintenance print objfiles
 375         printpsyms ->           maintenance print psymbols
 376         printsyms ->            maintenance print symbols
 377
 378 The following commands are new:
 379
 380         maintenance demangle    Call internal GDB demangler routine to
 381                                 demangle a C++ link name and prints the result.
 382         maintenance print type  Print a type chain for a given symbol
 383
 384  * Change to .gdbinit file processing
 385
 386 We now read the $HOME/.gdbinit file before processing the argv arguments
 387 (e.g. reading symbol files or core files).  This allows global parameters to
 388 be set, which will apply during the symbol reading.  The ./.gdbinit is still
 389 read after argv processing.
 390
 391  * New hosts supported
 392
 393 Solaris-2.0 !!!                         sparc-sun-solaris2  or  sun4sol2
 394
 395 Linux support                           i386-unknown-linux  or  linux
 396
 397 We are also including code to support the HP/PA running BSD and HPUX.  This
 398 is almost guaranteed not to work, as we didn't have time to test or build it
 399 for this release.  We are including it so that the more adventurous (or
 400 masochistic) of you can play with it.  We also had major problems with the
 401 fact that the compiler that we got from HP doesn't support the -g option.
 402 It costs extra.
 403
 404  * New targets supported
 405
 406 Hitachi H8/300                          h8300-hitachi-hms  or  h8300hms
 407
 408  * More smarts about finding #include files
 409
 410 GDB now remembers the compilation directory for all include files, and for
 411 all files from which C is generated (like yacc and lex sources).  This
 412 greatly improves GDB's ability to find yacc/lex sources, and include files,
 413 especially if you are debugging your program from a directory different from
 414 the one that contains your sources.
 415
 416 We also fixed a bug which caused difficulty with listing and setting
 417 breakpoints in include files which contain C code.  (In the past, you had to
 418 try twice in order to list an include file that you hadn't looked at before.)
 419
 420  * Interesting infernals change
 421
 422 GDB now deals with arbitrary numbers of sections, where the symbols for each
 423 section must be relocated relative to that section's landing place in the
 424 target's address space.  This work was needed to support ELF with embedded
 425 stabs used by Solaris-2.0.
 426
 427  * Bug fixes (of course!)
 428
 429 There have been loads of fixes for the following things:
 430         mips, rs6000, 29k/udi, m68k, g++, type handling, elf/dwarf, m88k,
 431         i960, stabs, DOS(GO32), procfs, etc...
 432
 433 See the ChangeLog for details.
 434
 435 *** Changes in GDB-4.5:
 436
 437  * New machines supported (host and target)
 438
 439 IBM RS6000 running AIX                  rs6000-ibm-aix  or rs6000
 440
 441 SGI Irix-4.x                            mips-sgi-irix4  or iris4
 442
 443  * New malloc package
 444
 445 GDB now uses a new memory manager called mmalloc, based on gmalloc.
 446 Mmalloc is capable of handling mutiple heaps of memory.  It is also
 447 capable of saving a heap to a file, and then mapping it back in later.
 448 This can be used to greatly speedup the startup of GDB by using a
 449 pre-parsed symbol table which lives in a mmalloc managed heap.  For
 450 more details, please read mmalloc/mmalloc.texi.
 451
 452  * info proc
 453
 454 The 'info proc' command (SVR4 only) has been enhanced quite a bit.  See
 455 'help info proc' for details.
 456
 457  * MIPS ecoff symbol table format
 458
 459 The code that reads MIPS symbol table format is now supported on all hosts.
 460 Thanks to MIPS for releasing the sym.h and symconst.h files to make this
 461 possible.
 462
 463  * File name changes for MS-DOS
 464
 465 Many files in the config directories have been renamed to make it easier to
 466 support GDB on MS-DOSe systems (which have very restrictive file name
 467 conventions :-( ).  MS-DOSe host support (under DJ Delorie's GO32
 468 environment) is close to working but has some remaining problems.  Note
 469 that debugging of DOS programs is not supported, due to limitations
 470 in the ``operating system'', but it can be used to host cross-debugging.
 471
 472  * Cross byte order fixes
 473
 474 Many fixes have been made to support cross debugging of Sparc and MIPS
 475 targets from hosts whose byte order differs.
 476
 477  * New -mapped and -readnow options
 478
 479 If memory-mapped files are available on your system through the 'mmap'
 480 system call, you can use the -mapped option on the `file' or
 481 `symbol-file' commands to cause GDB to write the symbols from your
 482 program into a reusable file.  If the program you are debugging is
 483 called `/path/fred', the mapped symbol file will be `./fred.syms'.
 484 Future GDB debugging sessions will notice the presence of this file,
 485 and will quickly map in symbol information from it, rather than reading
 486 the symbol table from the executable program.  Using the '-mapped'
 487 option in a GDB `file' or `symbol-file' command has the same effect as
 488 starting GDB with the '-mapped' command-line option.
 489
 490 You can cause GDB to read the entire symbol table immediately by using
 491 the '-readnow' option with any of the commands that load symbol table
 492 information (or on the GDB command line).  This makes the command
 493 slower, but makes future operations faster.
 494
 495 The -mapped and -readnow options are typically combined in order to
 496 build a `fred.syms' file that contains complete symbol information.
 497 A simple GDB invocation to do nothing but build a `.syms' file for future
 498 use is:
 499
 500         gdb -batch -nx -mapped -readnow programname
 501
 502 The `.syms' file is specific to the host machine on which GDB is run.
 503 It holds an exact image of GDB's internal symbol table.  It cannot be
 504 shared across multiple host platforms.
 505
 506  * longjmp() handling
 507
 508 GDB is now capable of stepping and nexting over longjmp(), _longjmp(), and
 509 siglongjmp() without losing control.  This feature has not yet been ported to
 510 all systems.  It currently works on many 386 platforms, all MIPS-based
 511 platforms (SGI, DECstation, etc), and Sun3/4.
 512
 513  * Solaris 2.0
 514
 515 Preliminary work has been put in to support the new Solaris OS from Sun.  At
 516 this time, it can control and debug processes, but it is not capable of
 517 reading symbols.
 518
 519  * Bug fixes
 520
 521 As always, many many bug fixes.  The major areas were with g++, and mipsread.
 522 People using the MIPS-based platforms should experience fewer mysterious
 523 crashes and trashed symbol tables.
 524
 525 *** Changes in GDB-4.4:
 526
 527  * New machines supported (host and target)
 528
 529 SCO Unix on i386 IBM PC clones          i386-sco-sysv   or  i386sco
 530         (except core files)
 531 BSD Reno on Vax                         vax-dec-bsd
 532 Ultrix on Vax                           vax-dec-ultrix
 533
 534  * New machines supported (target)
 535
 536 AMD 29000 embedded, using EBMON         a29k-none-none
 537
 538  * C++ support
 539
 540 GDB continues to improve its handling of C++.  `References' work better.
 541 The demangler has also been improved, and now deals with symbols mangled as
 542 per the Annotated C++ Reference Guide.
 543
 544 GDB also now handles `stabs' symbol information embedded in MIPS
 545 `ecoff' symbol tables.  Since the ecoff format was not easily
 546 extensible to handle new languages such as C++, this appeared to be a
 547 good way to put C++ debugging info into MIPS binaries.  This option
 548 will be supported in the GNU C compiler, version 2, when it is
 549 released.
 550
 551  * New features for SVR4
 552
 553 GDB now handles SVR4 shared libraries, in the same fashion as SunOS
 554 shared libraries.  Debugging dynamically linked programs should present
 555 only minor differences from debugging statically linked programs.
 556
 557 The `info proc' command will print out information about any process
 558 on an SVR4 system (including the one you are debugging).  At the moment,
 559 it prints the address mappings of the process.
 560
 561 If you bring up GDB on another SVR4 system, please send mail to
 562 bug-gdb@prep.ai.mit.edu to let us know what changes were reqired (if any).
 563
 564  * Better dynamic linking support in SunOS
 565
 566 Reading symbols from shared libraries which contain debugging symbols
 567 now works properly.  However, there remain issues such as automatic
 568 skipping of `transfer vector' code during function calls, which
 569 make it harder to debug code in a shared library, than to debug the
 570 same code linked statically.
 571
 572  * New Getopt
 573
 574 GDB is now using the latest `getopt' routines from the FSF.  This
 575 version accepts the -- prefix for options with long names.  GDB will
 576 continue to accept the old forms (-option and +option) as well.
 577 Various single letter abbreviations for options have been explicity
 578 added to the option table so that they won't get overshadowed in the
 579 future by other options that begin with the same letter.
 580
 581  * Bugs fixed
 582
 583 The `cleanup_undefined_types' bug that many of you noticed has been squashed.
 584 Many assorted bugs have been handled.  Many more remain to be handled.
 585 See the various ChangeLog files (primarily in gdb and bfd) for details.
 586
 587
 588 *** Changes in GDB-4.3:
 589
 590  * New machines supported (host and target)
 591
 592 Amiga 3000 running Amix                 m68k-cbm-svr4   or  amix
 593 NCR 3000 386 running SVR4               i386-ncr-svr4   or  ncr3000
 594 Motorola Delta 88000 running Sys V      m88k-motorola-sysv  or  delta88
 595
 596  * Almost SCO Unix support
 597
 598 We had hoped to support:
 599 SCO Unix on i386 IBM PC clones          i386-sco-sysv   or  i386sco
 600 (except for core file support), but we discovered very late in the release
 601 that it has problems with process groups that render gdb unusable.  Sorry
 602 about that.  I encourage people to fix it and post the fixes.
 603
 604  * Preliminary ELF and DWARF support
 605
 606 GDB can read ELF object files on System V Release 4, and can handle
 607 debugging records for C, in DWARF format, in ELF files.  This support
 608 is preliminary.  If you bring up GDB on another SVR4 system, please
 609 send mail to bug-gdb@prep.ai.mit.edu to let us know what changes were
 610 reqired (if any).
 611
 612  * New Readline
 613
 614 GDB now uses the latest `readline' library.  One user-visible change
 615 is that two tabs will list possible command completions, which previously
 616 required typing M-? (meta-question mark, or ESC ?).
 617
 618  * Bugs fixed
 619
 620 The `stepi' bug that many of you noticed has been squashed.
 621 Many bugs in C++ have been handled.  Many more remain to be handled.
 622 See the various ChangeLog files (primarily in gdb and bfd) for details.
 623
 624  * State of the MIPS world (in case you wondered):
 625
 626 GDB can understand the symbol tables emitted by the compilers
 627 supplied by most vendors of MIPS-based machines, including DEC.  These
 628 symbol tables are in a format that essentially nobody else uses.
 629
 630 Some versions of gcc come with an assembler post-processor called
 631 mips-tfile.  This program is required if you want to do source-level
 632 debugging of gcc-compiled programs.  I believe FSF does not ship
 633 mips-tfile with gcc version 1, but it will eventually come with gcc
 634 version 2.
 635
 636 Debugging of g++ output remains a problem.  g++ version 1.xx does not
 637 really support it at all.  (If you're lucky, you should be able to get
 638 line numbers and stack traces to work, but no parameters or local
 639 variables.)  With some work it should be possible to improve the
 640 situation somewhat.
 641
 642 When gcc version 2 is released, you will have somewhat better luck.
 643 However, even then you will get confusing results for inheritance and
 644 methods.
 645
 646 We will eventually provide full debugging of g++ output on
 647 DECstations.  This will probably involve some kind of stabs-in-ecoff
 648 encapulation, but the details have not been worked out yet.
 649
 650
 651 *** Changes in GDB-4.2:
 652
 653  *  Improved configuration
 654
 655 Only one copy of `configure' exists now, and it is not self-modifying.
 656 Porting BFD is simpler.
 657
 658  *  Stepping improved
 659
 660 The `step' and `next' commands now only stop at the first instruction
 661 of a source line.  This prevents the multiple stops that used to occur
 662 in switch statements, for-loops, etc.  `Step' continues to stop if a
 663 function that has debugging information is called within the line.
 664
 665  *  Bug fixing
 666
 667 Lots of small bugs fixed.  More remain.
 668
 669  *  New host supported (not target)
 670
 671 Intel 386 PC clone running Mach         i386-none-mach
 672
 673
 674 *** Changes in GDB-4.1:
 675
 676  *  Multiple source language support
 677
 678 GDB now has internal scaffolding to handle several source languages.
 679 It determines the type of each source file from its filename extension,
 680 and will switch expression parsing and number formatting to match the
 681 language of the function in the currently selected stack frame.
 682 You can also specifically set the language to be used, with
 683 `set language c' or `set language modula-2'.
 684
 685  *  GDB and Modula-2
 686
 687 GDB now has preliminary support for the GNU Modula-2 compiler,
 688 currently under development at the State University of New York at
 689 Buffalo.  Development of both GDB and the GNU Modula-2 compiler will
 690 continue through the fall of 1991 and into 1992.
 691
 692 Other Modula-2 compilers are currently not supported, and attempting to
 693 debug programs compiled with them will likely result in an error as the
 694 symbol table is read.  Feel free to work on it, though!
 695
 696 There are hooks in GDB for strict type checking and range checking,
 697 in the `Modula-2 philosophy', but they do not currently work.
 698
 699  * set write on/off
 700
 701 GDB can now write to executable and core files (e.g. patch
 702 a variable's value).   You must turn this switch on, specify
 703 the file ("exec foo" or "core foo"), *then* modify it, e.g.
 704 by assigning a new value to a variable.  Modifications take
 705 effect immediately.
 706
 707  * Automatic SunOS shared library reading
 708
 709 When you run your program, GDB automatically determines where its
 710 shared libraries (if any) have been loaded, and reads their symbols.
 711 The `share' command is no longer needed.  This also works when
 712 examining core files.
 713
 714  * set listsize
 715
 716 You can specify the number of lines that the `list' command shows.
 717 The default is 10.
 718
 719  * New machines supported (host and target)
 720
 721 SGI Iris (MIPS) running Irix V3:        mips-sgi-irix   or  iris
 722 Sony NEWS (68K) running NEWSOS 3.x:     m68k-sony-sysv  or  news
 723 Ultracomputer (29K) running Sym1:       a29k-nyu-sym1   or  ultra3
 724
 725  * New hosts supported (not targets)
 726
 727 IBM RT/PC:                              romp-ibm-aix    or  rtpc
 728
 729  * New targets supported (not hosts)
 730
 731 AMD 29000 embedded with COFF            a29k-none-coff
 732 AMD 29000 embedded with a.out           a29k-none-aout
 733 Ultracomputer remote kernel debug       a29k-nyu-kern
 734
 735  * New remote interfaces
 736
 737 AMD 29000 Adapt
 738 AMD 29000 Minimon
 739
 740
 741 *** Changes in GDB-4.0:
 742
 743  *  New Facilities
 744
 745 Wide output is wrapped at good places to make the output more readable.
 746
 747 Gdb now supports cross-debugging from a host machine of one type to a
 748 target machine of another type.  Communication with the target system
 749 is over serial lines.  The ``target'' command handles connecting to the
 750 remote system; the ``load'' command will download a program into the
 751 remote system.  Serial stubs for the m68k and i386 are provided.  Gdb
 752 also supports debugging of realtime processes running under VxWorks,
 753 using SunRPC Remote Procedure Calls over TCP/IP to talk to a debugger
 754 stub on the target system.
 755
 756 New CPUs supported include the AMD 29000 and Intel 960.
 757
 758 GDB now reads object files and symbol tables via a ``binary file''
 759 library, which allows a single copy of GDB to debug programs of multiple
 760 object file types such as a.out and coff.
 761
 762 There is now a GDB reference card in "doc/refcard.tex".  (Make targets
 763 refcard.dvi and refcard.ps are available to format it).
 764
 765
 766  *  Control-Variable user interface simplified
 767
 768 All variables that control the operation of the debugger can be set
 769 by the ``set'' command, and displayed by the ``show'' command.
 770
 771 For example, ``set prompt new-gdb=>'' will change your prompt to new-gdb=>.
 772 ``Show prompt'' produces the response:
 773 Gdb's prompt is new-gdb=>.
 774
 775 What follows are the NEW set commands.  The command ``help set'' will
 776 print a complete list of old and new set commands.  ``help set FOO''
 777 will give a longer description of the variable FOO.  ``show'' will show
 778 all of the variable descriptions and their current settings.
 779
 780 confirm on/off:  Enables warning questions for operations that are
 781                  hard to recover from, e.g. rerunning the program while
 782                  it is already running.  Default is ON.
 783
 784 editing on/off:  Enables EMACS style command line editing
 785                  of input.  Previous lines can be recalled with
 786                  control-P, the current line can be edited with control-B,
 787                  you can search for commands with control-R, etc.
 788                  Default is ON.
 789
 790 history filename NAME:  NAME is where the gdb command history
 791                         will be stored.  The default is .gdb_history,
 792                         or the value of the environment variable
 793                         GDBHISTFILE.
 794
 795 history size N:  The size, in commands, of the command history.  The
 796                  default is 256, or the value of the environment variable
 797                  HISTSIZE.
 798
 799 history save on/off: If this value is set to ON, the history file will
 800                       be saved after exiting gdb.  If set to OFF, the
 801                       file will not be saved.  The default is OFF.
 802
 803 history expansion on/off: If this value is set to ON, then csh-like
 804                           history expansion will be performed  on
 805                           command line input.  The default is OFF.
 806
 807 radix N:  Sets the default radix for input and output.  It can be set
 808           to 8, 10, or 16.  Note that the argument to "radix" is interpreted
 809           in the current radix, so "set radix 10" is always a no-op.
 810
 811 height N: This integer value is the number of lines on a page. Default
 812           is 24, the current `stty rows'' setting, or the ``li#''
 813           setting from the termcap entry matching the environment
 814           variable TERM.
 815
 816 width N:  This integer value is the number of characters on a line.
 817           Default is 80, the current `stty cols'' setting, or the ``co#''
 818           setting from the termcap entry matching the environment
 819           variable TERM.
 820
 821 Note: ``set screensize'' is obsolete. Use ``set height'' and
 822 ``set width'' instead.
 823
 824 print address on/off:  Print memory addresses in various command displays,
 825                       such as stack traces and structure values.  Gdb looks
 826                       more ``symbolic'' if you turn this off; it looks more
 827                       ``machine level'' with it on.  Default is ON.
 828
 829 print array on/off:  Prettyprint arrays.  New convenient format!  Default
 830                     is OFF.
 831
 832 print demangle on/off:   Print C++ symbols in "source" form if on,
 833                         "raw" form if off.
 834
 835 print asm-demangle on/off:  Same, for assembler level printouts
 836                         like instructions.
 837
 838 print vtbl on/off:  Prettyprint C++ virtual function tables.  Default is OFF.
 839
 840
 841  *  Support for Epoch Environment.
 842
 843 The epoch environment is a version of Emacs v18 with windowing.  One
 844 new command, ``inspect'', is identical to ``print'', except that if you
 845 are running in the epoch environment, the value is printed in its own
 846 window.
 847
 848
 849  *  Support for Shared Libraries
 850
 851 GDB can now debug programs and core files that use SunOS shared libraries.
 852 Symbols from a shared library cannot be referenced
 853 before the shared library has been linked with the program (this
 854 happens after you type ``run'' and before the function main() is entered).
 855 At any time after this linking (including when examining core files
 856 from dynamically linked programs), gdb reads the symbols from each
 857 shared library when you type the ``sharedlibrary'' command.
 858 It can be abbreviated ``share''.
 859
 860 sharedlibrary REGEXP:  Load shared object library symbols for files
 861                        matching a unix regular expression.  No argument
 862                        indicates to load symbols for all shared libraries.
 863
 864 info sharedlibrary:  Status of loaded shared libraries.
 865
 866
 867  *  Watchpoints
 868
 869 A watchpoint stops execution of a program whenever the value of an
 870 expression changes.  Checking for this slows down execution
 871 tremendously whenever you are in the scope of the expression, but is
 872 quite useful for catching tough ``bit-spreader'' or pointer misuse
 873 problems.  Some machines such as the 386 have hardware for doing this
 874 more quickly, and future versions of gdb will use this hardware.
 875
 876 watch EXP:  Set a watchpoint (breakpoint) for an expression.
 877
 878 info watchpoints:  Information about your watchpoints.
 879
 880 delete N:   Deletes watchpoint number N (same as breakpoints).
 881 disable N:  Temporarily turns off watchpoint number N (same as breakpoints).
 882 enable N:   Re-enables watchpoint number N (same as breakpoints).
 883
 884
 885  *  C++ multiple inheritance
 886
 887 When used with a GCC version 2 compiler, GDB supports multiple inheritance
 888 for C++ programs.
 889
 890  *  C++ exception handling
 891
 892 Gdb now supports limited C++ exception handling.  Besides the existing
 893 ability to breakpoint on an exception handler, gdb can breakpoint on
 894 the raising of an exception (before the stack is peeled back to the
 895 handler's context).
 896
 897 catch FOO:  If there is a FOO exception handler in the dynamic scope,
 898             set a breakpoint to catch exceptions which may be raised there.
 899             Multiple exceptions (``catch foo bar baz'') may be caught.
 900
 901 info catch:  Lists all exceptions which may be caught in the
 902              current stack frame.
 903
 904
 905  *  Minor command changes
 906
 907 The command ``call func (arg, arg, ...)'' now acts like the print
 908 command, except it does not print or save a value if the function's result
 909 is void.  This is similar to dbx usage.
 910
 911 The ``up'' and ``down'' commands now always print the frame they end up
 912 at; ``up-silently'' and `down-silently'' can be used in scripts to change
 913 frames without printing.
 914
 915  *  New directory command
 916
 917 'dir' now adds directories to the FRONT of the source search path.
 918 The path starts off empty.  Source files that contain debug information
 919 about the directory in which they were compiled can be found even
 920 with an empty path; Sun CC and GCC include this information.  If GDB can't
 921 find your source file in the current directory, type "dir .".
 922
 923  * Configuring GDB for compilation
 924
 925 For normal use, type ``./configure host''.  See README or gdb.texinfo
 926 for more details.
 927
 928 GDB now handles cross debugging.  If you are remotely debugging between
 929 two different machines, type ``./configure host -target=targ''.
 930 Host is the machine where GDB will run; targ is the machine
 931 where the program that you are debugging will run.