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