gdb/WHATS.NEW

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