gdb/WHATS.NEW

   1                 What has changed since GDB-3.5?
   2                 (Organized release by release)
   3
   4 *** Changes in GDB-4.4:
   5
   6  * New machines supported (host and target)
   7
   8 SCO Unix on i386 IBM PC clones          i386-sco-sysv   or  i386sco
   9         (except core files)
  10
  11 BSD Reno on Vaxen                       vax-dec-bsd
  12 Ultrix on Vaxen                         vax-dec-ultrix
  13
  14  * New machines supported (target)
  15
  16 AMD 29000 embedded, using EBMON         a29k-none-none
  17
  18  * C++ stuff
  19
  20 Improvements have been made in the way GDB handles C++ references.  The
  21 demangler has also been improved, and now deals with symbols mangled as
  22 per the Annotated C++ Reference Guide.  GDB also now handles stabs embedded in
  23 MIPS symbol tables (which was the only way to get C++ debugging info into MIPS
  24 binaries).  This will become useful in a future version of G++.
  25
  26  * New features for SVR4
  27
  28 The `info process' command will print out process information.
  29
  30 Better shared library support for SVR4 and SunOS.
  31
  32         Info proc, improved SVR4, shared libs
  33
  34
  35 ***FIXME * Improved ELF and DWARF support
  36
  37 GDB can read ELF object files on System V Release 4, and can handle
  38 debugging records for C, in DWARF format, in ELF files.  This support
  39 is preliminary.  If you bring up GDB on another SVR4 system, please
  40 send mail to bug-gdb@prep.ai.mit.edu to let us know what changes were
  41 reqired (if any).
  42
  43  * New Getopt
  44
  45 GDB is now using the latest `getopt' routines from the FSF.  This version
  46 now accepts the -- prefix for options with long names.  Note that gdb will
  47 continue to accept the old format as well.  Also, various single letter
  48 abbreviations for options have been explicity added to the option table so that
  49 they won't get overshadowed in the future by other options that begin with the
  50 same letter.
  51
  52 ***FIXME * Bugs fixed
  53
  54 The `stepi' bug that many of you noticed has been squashed.
  55 Many bugs in C++ have been handled.  Many more remain to be handled.
  56 See the various ChangeLog files (primarily in gdb and bfd) for details.
  57
  58 ***FIXME * State of the MIPS world (in case you wondered):
  59
  60 blah blah blah.....................................
  61 ===============================================================================
  62
  63
  64 *** Changes in GDB-4.3:
  65
  66  * New machines supported (host and target)
  67
  68 Amiga 3000 running Amix                 m68k-cbm-svr4   or  amix
  69 NCR 3000 386 running SVR4               i386-ncr-svr4   or  ncr3000
  70 Motorola Delta 88000 running Sys V      m88k-motorola-sysv  or  delta88
  71
  72  * Almost SCO Unix support
  73
  74 We had hoped to support:
  75 SCO Unix on i386 IBM PC clones          i386-sco-sysv   or  i386sco
  76 (except for core file support), but we discovered very late in the release
  77 that it has problems with process groups that render gdb unusable.  Sorry
  78 about that.  I encourage people to fix it and post the fixes.
  79
  80  * Preliminary ELF and DWARF support
  81
  82 GDB can read ELF object files on System V Release 4, and can handle
  83 debugging records for C, in DWARF format, in ELF files.  This support
  84 is preliminary.  If you bring up GDB on another SVR4 system, please
  85 send mail to bug-gdb@prep.ai.mit.edu to let us know what changes were
  86 reqired (if any).
  87
  88  * New Readline
  89
  90 GDB now uses the latest `readline' library.  One user-visible change
  91 is that two tabs will list possible command completions, which previously
  92 required typing M-? (meta-question mark, or ESC ?).
  93
  94  * Bugs fixed
  95
  96 The `stepi' bug that many of you noticed has been squashed.
  97 Many bugs in C++ have been handled.  Many more remain to be handled.
  98 See the various ChangeLog files (primarily in gdb and bfd) for details.
  99
 100  * State of the MIPS world (in case you wondered):
 101
 102 GDB can understand the symbol tables emitted by the compilers
 103 supplied by most vendors of MIPS-based machines, including DEC.  These
 104 symbol tables are in a format that essentially nobody else uses.
 105
 106 Some versions of gcc come with an assembler post-processor called
 107 mips-tfile.  This program is required if you want to do source-level
 108 debugging of gcc-compiled programs.  I believe FSF does not ship
 109 mips-tfile with gcc version 1, but it will eventually come with gcc
 110 version 2.
 111
 112 Debugging of g++ output remains a problem.  g++ version 1.xx does not
 113 really support it at all.  (If you're lucky, you should be able to get
 114 line numbers and stack traces to work, but no parameters or local
 115 variables.)  With some work it should be possible to improve the
 116 situation somewhat.
 117
 118 When gcc version 2 is released, you will have somewhat better luck.
 119 However, even then you will get confusing results for inheritance and
 120 methods.
 121
 122 We will eventually provide full debugging of g++ output on
 123 DECstations.  This will probably involve some kind of stabs-in-ecoff
 124 encapulation, but the details have not been worked out yet.
 125
 126
 127 *** Changes in GDB-4.2:
 128
 129  *  Improved configuration
 130
 131 Only one copy of `configure' exists now, and it is not self-modifying.
 132 Porting BFD is simpler.
 133
 134  *  Stepping improved
 135
 136 The `step' and `next' commands now only stop at the first instruction
 137 of a source line.  This prevents the multiple stops that used to occur
 138 in switch statements, for-loops, etc.  `Step' continues to stop if a
 139 function that has debugging information is called within the line.
 140
 141  *  Bug fixing
 142
 143 Lots of small bugs fixed.  More remain.
 144
 145  *  New host supported (not target)
 146
 147 Intel 386 PC clone running Mach         i386-none-mach
 148
 149
 150 *** Changes in GDB-4.1:
 151
 152  *  Multiple source language support
 153
 154 GDB now has internal scaffolding to handle several source languages.
 155 It determines the type of each source file from its filename extension,
 156 and will switch expression parsing and number formatting to match the
 157 language of the function in the currently selected stack frame.
 158 You can also specifically set the language to be used, with
 159 `set language c' or `set language modula-2'.
 160
 161  *  GDB and Modula-2
 162
 163 GDB now has preliminary support for the GNU Modula-2 compiler,
 164 currently under development at the State University of New York at
 165 Buffalo.  Development of both GDB and the GNU Modula-2 compiler will
 166 continue through the fall of 1991 and into 1992.
 167
 168 Other Modula-2 compilers are currently not supported, and attempting to
 169 debug programs compiled with them will likely result in an error as the
 170 symbol table is read.  Feel free to work on it, though!
 171
 172 There are hooks in GDB for strict type checking and range checking,
 173 in the `Modula-2 philosophy', but they do not currently work.
 174
 175  * set write on/off
 176
 177 GDB can now write to executable and core files (e.g. patch
 178 a variable's value).   You must turn this switch on, specify
 179 the file ("exec foo" or "core foo"), *then* modify it, e.g.
 180 by assigning a new value to a variable.  Modifications take
 181 effect immediately.
 182
 183  * Automatic SunOS shared library reading
 184
 185 When you run your program, GDB automatically determines where its
 186 shared libraries (if any) have been loaded, and reads their symbols.
 187 The `share' command is no longer needed.  This also works when
 188 examining core files.
 189
 190  * set listsize
 191
 192 You can specify the number of lines that the `list' command shows.
 193 The default is 10.
 194
 195  * New machines supported (host and target)
 196
 197 SGI Iris (MIPS) running Irix V3:        mips-sgi-irix   or  iris
 198 Sony NEWS (68K) running NEWSOS 3.x:     m68k-sony-sysv  or  news
 199 Ultracomputer (29K) running Sym1:       a29k-nyu-sym1   or  ultra3
 200
 201  * New hosts supported (not targets)
 202
 203 IBM RT/PC:                              romp-ibm-aix    or  rtpc
 204
 205  * New targets supported (not hosts)
 206
 207 AMD 29000 embedded with COFF            a29k-none-coff
 208 AMD 29000 embedded with a.out           a29k-none-aout
 209 Ultracomputer remote kernel debug       a29k-nyu-kern
 210
 211  * New remote interfaces
 212
 213 AMD 29000 Adapt
 214 AMD 29000 Minimon
 215
 216
 217 *** Changes in GDB-4.0:
 218
 219  *  New Facilities
 220
 221 Wide output is wrapped at good places to make the output more readable.
 222
 223 Gdb now supports cross-debugging from a host machine of one type to a
 224 target machine of another type.  Communication with the target system
 225 is over serial lines.  The ``target'' command handles connecting to the
 226 remote system; the ``load'' command will download a program into the
 227 remote system.  Serial stubs for the m68k and i386 are provided.  Gdb
 228 also supports debugging of realtime processes running under VxWorks,
 229 using SunRPC Remote Procedure Calls over TCP/IP to talk to a debugger
 230 stub on the target system.
 231
 232 New CPUs supported include the AMD 29000 and Intel 960.
 233
 234 GDB now reads object files and symbol tables via a ``binary file''
 235 library, which allows a single copy of GDB to debug programs of multiple
 236 object file types such as a.out and coff.
 237
 238 There is now a GDB reference card in "doc/refcard.tex".  (Make targets
 239 refcard.dvi and refcard.ps are available to format it).
 240
 241
 242  *  Control-Variable user interface simplified
 243
 244 All variables that control the operation of the debugger can be set
 245 by the ``set'' command, and displayed by the ``show'' command.
 246
 247 For example, ``set prompt new-gdb=>'' will change your prompt to new-gdb=>.
 248 ``Show prompt'' produces the response:
 249 Gdb's prompt is new-gdb=>.
 250
 251 What follows are the NEW set commands.  The command ``help set'' will
 252 print a complete list of old and new set commands.  ``help set FOO''
 253 will give a longer description of the variable FOO.  ``show'' will show
 254 all of the variable descriptions and their current settings.
 255
 256 confirm on/off:  Enables warning questions for operations that are
 257                  hard to recover from, e.g. rerunning the program while
 258                  it is already running.  Default is ON.
 259
 260 editing on/off:  Enables EMACS style command line editing
 261                  of input.  Previous lines can be recalled with
 262                  control-P, the current line can be edited with control-B,
 263                  you can search for commands with control-R, etc.
 264                  Default is ON.
 265
 266 history filename NAME:  NAME is where the gdb command history
 267                         will be stored.  The default is .gdb_history,
 268                         or the value of the environment variable
 269                         GDBHISTFILE.
 270
 271 history size N:  The size, in commands, of the command history.  The
 272                  default is 256, or the value of the environment variable
 273                  HISTSIZE.
 274
 275 history save on/off: If this value is set to ON, the history file will
 276                       be saved after exiting gdb.  If set to OFF, the
 277                       file will not be saved.  The default is OFF.
 278
 279 history expansion on/off: If this value is set to ON, then csh-like
 280                           history expansion will be performed  on
 281                           command line input.  The default is OFF.
 282
 283 radix N:  Sets the default radix for input and output.  It can be set
 284           to 8, 10, or 16.  Note that the argument to "radix" is interpreted
 285           in the current radix, so "set radix 10" is always a no-op.
 286
 287 height N: This integer value is the number of lines on a page. Default
 288           is 24, the current `stty rows'' setting, or the ``li#''
 289           setting from the termcap entry matching the environment
 290           variable TERM.
 291
 292 width N:  This integer value is the number of characters on a line.
 293           Default is 80, the current `stty cols'' setting, or the ``co#''
 294           setting from the termcap entry matching the environment
 295           variable TERM.
 296
 297 Note: ``set screensize'' is obsolete. Use ``set height'' and
 298 ``set width'' instead.
 299
 300 print address on/off:  Print memory addresses in various command displays,
 301                       such as stack traces and structure values.  Gdb looks
 302                       more ``symbolic'' if you turn this off; it looks more
 303                       ``machine level'' with it on.  Default is ON.
 304
 305 print array on/off:  Prettyprint arrays.  New convenient format!  Default
 306                     is OFF.
 307
 308 print demangle on/off:   Print C++ symbols in "source" form if on,
 309                         "raw" form if off.
 310
 311 print asm-demangle on/off:  Same, for assembler level printouts
 312                         like instructions.
 313
 314 print vtbl on/off:  Prettyprint C++ virtual function tables.  Default is OFF.
 315
 316
 317  *  Support for Epoch Environment.
 318
 319 The epoch environment is a version of Emacs v18 with windowing.  One
 320 new command, ``inspect'', is identical to ``print'', except that if you
 321 are running in the epoch environment, the value is printed in its own
 322 window.
 323
 324
 325  *  Support for Shared Libraries
 326
 327 GDB can now debug programs and core files that use SunOS shared libraries.
 328 Symbols from a shared library cannot be referenced
 329 before the shared library has been linked with the program (this
 330 happens after you type ``run'' and before the function main() is entered).
 331 At any time after this linking (including when examining core files
 332 from dynamically linked programs), gdb reads the symbols from each
 333 shared library when you type the ``sharedlibrary'' command.
 334 It can be abbreviated ``share''.
 335
 336 sharedlibrary REGEXP:  Load shared object library symbols for files
 337                        matching a unix regular expression.  No argument
 338                        indicates to load symbols for all shared libraries.
 339
 340 info sharedlibrary:  Status of loaded shared libraries.
 341
 342
 343  *  Watchpoints
 344
 345 A watchpoint stops execution of a program whenever the value of an
 346 expression changes.  Checking for this slows down execution
 347 tremendously whenever you are in the scope of the expression, but is
 348 quite useful for catching tough ``bit-spreader'' or pointer misuse
 349 problems.  Some machines such as the 386 have hardware for doing this
 350 more quickly, and future versions of gdb will use this hardware.
 351
 352 watch EXP:  Set a watchpoint (breakpoint) for an expression.
 353
 354 info watchpoints:  Information about your watchpoints.
 355
 356 delete N:   Deletes watchpoint number N (same as breakpoints).
 357 disable N:  Temporarily turns off watchpoint number N (same as breakpoints).
 358 enable N:   Re-enables watchpoint number N (same as breakpoints).
 359
 360
 361  *  C++ multiple inheritance
 362
 363 When used with a GCC version 2 compiler, GDB supports multiple inheritance
 364 for C++ programs.
 365
 366  *  C++ exception handling
 367
 368 Gdb now supports limited C++ exception handling.  Besides the existing
 369 ability to breakpoint on an exception handler, gdb can breakpoint on
 370 the raising of an exception (before the stack is peeled back to the
 371 handler's context).
 372
 373 catch FOO:  If there is a FOO exception handler in the dynamic scope,
 374             set a breakpoint to catch exceptions which may be raised there.
 375             Multiple exceptions (``catch foo bar baz'') may be caught.
 376
 377 info catch:  Lists all exceptions which may be caught in the
 378              current stack frame.
 379
 380
 381  *  Minor command changes
 382
 383 The command ``call func (arg, arg, ...)'' now acts like the print
 384 command, except it does not print or save a value if the function's result
 385 is void.  This is similar to dbx usage.
 386
 387 The ``up'' and ``down'' commands now always print the frame they end up
 388 at; ``up-silently'' and `down-silently'' can be used in scripts to change
 389 frames without printing.
 390
 391  *  New directory command
 392
 393 'dir' now adds directories to the FRONT of the source search path.
 394 The path starts off empty.  Source files that contain debug information
 395 about the directory in which they were compiled can be found even
 396 with an empty path; Sun CC and GCC include this information.  If GDB can't
 397 find your source file in the current directory, type "dir .".
 398
 399  * Configuring GDB for compilation
 400
 401 For normal use, type ``./configure host''.  See README or gdb.texinfo
 402 for more details.
 403
 404 GDB now handles cross debugging.  If you are remotely debugging between
 405 two different machines, type ``./configure host -target=targ''.
 406 Host is the machine where gdb will run; targ is the machine
 407 where the program that you are debugging will run.