gdb/README

   1                       README for gdb-4.9 release
   2                     Updated 10-May-93 by Fred Fish
   3
   4 This is GDB, the GNU source-level debugger, presently running under un*x.
   5 A summary of new features is in the file `NEWS'.
   6
   7
   8 Unpacking and Installation -- quick overview
   9 ==========================
  10
  11 In this release, the GDB debugger sources, the generic GNU include
  12 files, the BFD ("binary file description") library, the readline
  13 library, and other libraries all have directories of their own
  14 underneath the gdb-4.9 directory.  The idea is that a variety of GNU
  15 tools can share a common copy of these things.  Be aware of variation
  16 over time--for example don't try to build gdb with a copy of bfd from
  17 a release other than the gdb release (such as a binutils or gas
  18 release), especially if the releases are more than a few weeks apart.
  19 Configuration scripts and makefiles exist to cruise up and down this
  20 directory tree and automatically build all the pieces in the right
  21 order.
  22
  23 When you unpack the gdb-4.9.tar.z or gdb-4.9.tar.Z file, you'll find
  24 a directory called `gdb-4.9', which contains:
  25
  26   Makefile.in      config.sub*      glob/            opcodes/
  27   README           configure*       include/         readline/
  28   bfd/             configure.in     libiberty/       texinfo/
  29   config/          etc/             mmalloc/
  30   config.guess*    gdb/             move-if-change*
  31
  32 To build GDB, you can just do:
  33
  34         cd gdb-4.9
  35         ./configure
  36         make
  37         cp gdb/gdb /usr/local/bin/gdb   (or wherever you want)
  38
  39 This will configure and build all the libraries as well as GDB.
  40 If `configure' can't determine your system type, specify one as its
  41 argument, e.g. sun4 or decstation.
  42
  43 If you get compiler warnings during this stage, see the `Reporting Bugs'
  44 section below; there are a few known problems.
  45
  46 GDB can be used as a cross-debugger, running on a machine of one type
  47 while debugging a program running on a machine of another type.  See below.
  48
  49
  50 More Documentation
  51 ******************
  52
  53    The GDB 4 release includes an already-formatted reference card,
  54 ready for printing with PostScript or GhostScript, in the `gdb'
  55 subdirectory of the main source directory.  (In `gdb-4.9/gdb/refcard.ps'.)
  56 If you can use PostScript or GhostScript with your printer, you can
  57 print the reference card immediately with `refcard.ps'.
  58
  59    The release also includes the source for the reference card.  You
  60 can format it, using TeX, by typing:
  61
  62      make refcard.dvi
  63
  64    The GDB reference card is designed to print in landscape mode on US
  65 "letter" size paper; that is, on a sheet 11 inches wide by 8.5 inches
  66 high.  You will need to specify this form of printing as an option to
  67 your DVI output program.
  68
  69    All the documentation for GDB comes as part of the machine-readable
  70 distribution.  The documentation is written in Texinfo format, which is
  71 a documentation system that uses a single source file to produce both
  72 on-line information and a printed manual.  You can use one of the Info
  73 formatting commands to create the on-line version of the documentation
  74 and TeX (or `texi2roff') to typeset the printed version.
  75
  76    GDB includes an already formatted copy of the on-line Info version of
  77 this manual in the `gdb' subdirectory.  The main Info file is
  78 `gdb-VERSION-NUMBER/gdb/gdb.info', and it refers to subordinate files
  79 matching `gdb.info*' in the same directory.  If necessary, you can
  80 print out these files, or read them with any editor; but they are
  81 easier to read using the `info' subsystem in GNU Emacs or the
  82 standalone `info' program, available as part of the GNU Texinfo
  83 distribution.
  84
  85    If you want to format these Info files yourself, you need one of the
  86 Info formatting programs, such as `texinfo-format-buffer' or `makeinfo'.
  87
  88    If you have `makeinfo' installed, and are in the top level GDB
  89 source directory (`gdb-4.9', in the case of version 4.9), you can make
  90 the Info file by typing:
  91
  92      cd gdb
  93      make gdb.info
  94
  95    If you want to typeset and print copies of this manual, you need TeX,
  96 a program to print its DVI output files, and `texinfo.tex', the Texinfo
  97 definitions file.
  98
  99    TeX is a typesetting program; it does not print files directly, but
 100 produces output files called DVI files.  To print a typeset document,
 101 you need a program to print DVI files.  If your system has TeX
 102 installed, chances are it has such a program.  The precise command to
 103 use depends on your system; `lpr -d' is common; another (for PostScript
 104 devices) is `dvips'.  The DVI print command may require a file name
 105 without any extension or a `.dvi' extension.
 106
 107    TeX also requires a macro definitions file called `texinfo.tex'.
 108 This file tells TeX how to typeset a document written in Texinfo
 109 format.  On its own, TeX cannot read, much less typeset a Texinfo file.
 110  `texinfo.tex' is distributed with GDB and is located in the
 111 `gdb-VERSION-NUMBER/texinfo' directory.
 112
 113    If you have TeX and a DVI printer program installed, you can typeset
 114 and print this manual.  First switch to the the `gdb' subdirectory of
 115 the main source directory (for example, to `gdb-4.9/gdb') and then type:
 116
 117      make gdb.dvi
 118
 119
 120 Installing GDB
 121 **************
 122
 123    GDB comes with a `configure' script that automates the process of
 124 preparing GDB for installation; you can then use `make' to build the
 125 `gdb' program.
 126
 127    The GDB distribution includes all the source code you need for GDB in
 128 a single directory, whose name is usually composed by appending the
 129 version number to `gdb'.
 130
 131    For example, the GDB version 4.9 distribution is in the `gdb-4.9'
 132 directory.  That directory contains:
 133
 134 `gdb-4.9/configure (and supporting files)'
 135      script for configuring GDB and all its supporting libraries.
 136
 137 `gdb-4.9/gdb'
 138      the source specific to GDB itself
 139
 140 `gdb-4.9/bfd'
 141      source for the Binary File Descriptor library
 142
 143 `gdb-4.9/include'
 144      GNU include files
 145
 146 `gdb-4.9/libiberty'
 147      source for the `-liberty' free software library
 148
 149 `gdb-4.9/opcodes'
 150      source for the library of opcode tables and disassemblers
 151
 152 `gdb-4.9/readline'
 153      source for the GNU command-line interface
 154
 155 `gdb-4.9/glob'
 156      source for the GNU filename pattern-matching subroutine
 157
 158 `gdb-4.9/mmalloc'
 159      source for the GNU memory-mapped malloc package
 160
 161 'gdb-4.9/sim'
 162      source for some simulators (z8000, H8/300, H8/500, etc)
 163
 164    The simplest way to configure and build GDB is to run `configure'
 165 from the `gdb-VERSION-NUMBER' source directory, which in this example
 166 is the `gdb-4.9' directory.
 167
 168    First switch to the `gdb-VERSION-NUMBER' source directory if you are
 169 not already in it; then run `configure'.  Pass the identifier for the
 170 platform on which GDB will run as an argument.
 171
 172    For example:
 173
 174      cd gdb-4.9
 175      ./configure HOST
 176      make
 177
 178 where HOST is an identifier such as `sun4' or `decstation', that
 179 identifies the platform where GDB will run.
 180
 181    Running `configure HOST' followed by `make' builds the `bfd',
 182 `readline', `mmalloc', and `libiberty' libraries, then `gdb' itself.
 183 The configured source files, and the binaries, are left in the
 184 corresponding source directories.
 185
 186    `configure' is a Bourne-shell (`/bin/sh') script; if your system
 187 does not recognize this automatically when you run a different shell,
 188 you may need to run `sh' on it explicitly:
 189
 190      sh configure HOST
 191
 192    If you run `configure' from a directory that contains source
 193 directories for multiple libraries or programs, such as the `gdb-4.9'
 194 source directory for version 4.9, `configure' creates configuration
 195 files for every directory level underneath (unless you tell it not to,
 196 with the `--norecursion' option).
 197
 198    You can run the `configure' script from any of the subordinate
 199 directories in the GDB distribution, if you only want to configure that
 200 subdirectory; but be sure to specify a path to it.
 201
 202    For example, with version 4.9, type the following to configure only
 203 the `bfd' subdirectory:
 204
 205      cd gdb-4.9/bfd
 206      ../configure HOST
 207
 208    You can install `gdb' anywhere; it has no hardwired paths. However,
 209 you should make sure that the shell on your path (named by the `SHELL'
 210 environment variable) is publicly readable.  Remember that GDB uses the
 211 shell to start your program--some systems refuse to let GDB debug child
 212 processes whose programs are not readable.
 213
 214
 215 Compiling GDB in another directory
 216 ==================================
 217
 218    If you want to run GDB versions for several host or target machines,
 219 you need a different `gdb' compiled for each combination of host and
 220 target.  `configure' is designed to make this easy by allowing you to
 221 generate each configuration in a separate subdirectory, rather than in
 222 the source directory.  If your `make' program handles the `VPATH'
 223 feature correctly (GNU `make' and SunOS 'make' are two that should),
 224 running `make' in each of these directories builds the `gdb' program
 225 specified there.
 226
 227    To build `gdb' in a separate directory, run `configure' with the
 228 `--srcdir' option to specify where to find the source. (You also need
 229 to specify a path to find `configure' itself from your working
 230 directory.  If the path to `configure' would be the same as the
 231 argument to `--srcdir', you can leave out the `--srcdir' option; it
 232 will be assumed.)
 233
 234    For example, with version 4.9, you can build GDB in a separate
 235 directory for a Sun 4 like this:
 236
 237      cd gdb-4.9
 238      mkdir ../gdb-sun4
 239      cd ../gdb-sun4
 240      ../gdb-4.9/configure sun4
 241      make
 242
 243    When `configure' builds a configuration using a remote source
 244 directory, it creates a tree for the binaries with the same structure
 245 (and using the same names) as the tree under the source directory.  In
 246 the example, you'd find the Sun 4 library `libiberty.a' in the
 247 directory `gdb-sun4/libiberty', and GDB itself in `gdb-sun4/gdb'.
 248
 249    One popular reason to build several GDB configurations in separate
 250 directories is to configure GDB for cross-compiling (where GDB runs on
 251 one machine--the host--while debugging programs that run on another
 252 machine--the target).  You specify a cross-debugging target by giving
 253 the `--target=TARGET' option to `configure'.
 254
 255    When you run `make' to build a program or library, you must run it
 256 in a configured directory--whatever directory you were in when you
 257 called `configure' (or one of its subdirectories).
 258
 259    The `Makefile' that `configure' generates in each source directory
 260 also runs recursively.  If you type `make' in a source directory such
 261 as `gdb-4.9' (or in a separate configured directory configured with
 262 `--srcdir=PATH/gdb-4.9'), you will build all the required libraries,
 263 and then build GDB.
 264
 265    When you have multiple hosts or targets configured in separate
 266 directories, you can run `make' on them in parallel (for example, if
 267 they are NFS-mounted on each of the hosts); they will not interfere
 268 with each other.
 269
 270
 271 Specifying names for hosts and targets
 272 ======================================
 273
 274    The specifications used for hosts and targets in the `configure'
 275 script are based on a three-part naming scheme, but some short
 276 predefined aliases are also supported.  The full naming scheme encodes
 277 three pieces of information in the following pattern:
 278
 279      ARCHITECTURE-VENDOR-OS
 280
 281    For example, you can use the alias `sun4' as a HOST argument or in a
 282 `--target=TARGET' option.  The equivalent full name is
 283 `sparc-sun-sunos4'.
 284
 285    The `configure' script accompanying GDB does not provide any query
 286 facility to list all supported host and target names or aliases.
 287 `configure' calls the Bourne shell script `config.sub' to map
 288 abbreviations to full names; you can read the script, if you wish, or
 289 you can use it to test your guesses on abbreviations--for example:
 290
 291      % sh config.sub sun4
 292      sparc-sun-sunos411
 293      % sh config.sub sun3
 294      m68k-sun-sunos411
 295      % sh config.sub decstation
 296      mips-dec-ultrix42
 297      % sh config.sub hp300bsd
 298      m68k-hp-bsd
 299      % sh config.sub i386v
 300      i386-unknown-sysv
 301      % sh config.sub i786v
 302      Invalid configuration `i786v': machine `i786v' not recognized
 303
 304 `config.sub' is also distributed in the GDB source directory
 305 (`gdb-4.9', for version 4.9).
 306
 307
 308 `configure' options
 309 ===================
 310
 311    Here is a summary of the `configure' options and arguments that are
 312 most often useful for building GDB.  `configure' also has several other
 313 options not listed here.  *note : (configure.info)What Configure Does,
 314 for a full explanation of `configure'.
 315
 316      configure [--help]
 317                [--prefix=DIR]
 318                [--srcdir=PATH]
 319                [--norecursion] [--rm]
 320                [--target=TARGET] HOST
 321
 322 You may introduce options with a single `-' rather than `--' if you
 323 prefer; but you may abbreviate option names if you use `--'.
 324
 325 `--help'
 326      Display a quick summary of how to invoke `configure'.
 327
 328 `-prefix=DIR'
 329      Configure the source to install programs and files under directory
 330      `DIR'.
 331
 332 `--srcdir=PATH'
 333      *Warning: using this option requires GNU `make', or another `make'
 334      that compatibly implements the `VPATH' feature.*
 335      Use this option to make configurations in directories separate
 336      from the GDB source directories.  Among other things, you can use
 337      this to build (or maintain) several configurations simultaneously,
 338      in separate directories.  `configure' writes configuration
 339      specific files in the current directory, but arranges for them to
 340      use the source in the directory PATH.  `configure' will create
 341      directories under the working directory in parallel to the source
 342      directories below PATH.
 343
 344 `--norecursion'
 345      Configure only the directory level where `configure' is executed;
 346      do not propagate configuration to subdirectories.
 347
 348 `--rm'
 349      Remove the configuration that the other arguments specify.
 350
 351 `--target=TARGET'
 352      Configure GDB for cross-debugging programs running on the specified
 353      TARGET.  Without this option, GDB is configured to debug programs
 354      that run on the same machine (HOST) as GDB itself.
 355
 356      There is no convenient way to generate a list of all available
 357      targets.
 358
 359 `HOST ...'
 360      Configure GDB to run on the specified HOST.
 361
 362      There is no convenient way to generate a list of all available
 363      hosts.
 364
 365 `configure' accepts other options, for compatibility with configuring
 366 other GNU tools recursively; but these are the only options that affect
 367 GDB or its supporting libraries.
 368
 369
 370 Languages other than C
 371 =======================
 372
 373 GDB provides some support for debugging C++ programs, however that support
 374 only works well with GNU C++, and even then only on systems that use stabs
 375 debugging format.  In particular, cfront based compilers such as Sun's C++
 376 are not fully supported.
 377
 378 GDB should work with FORTRAN programs.  If you have problems, please send a
 379 bug report; you may have to refer to some FORTRAN variables with a trailing
 380 underscore.
 381
 382 Pascal programs which use sets, subranges, file variables, or nested functions
 383 will not currently work.
 384
 385 Partial Modula-2 and Chill support is now in GDB.
 386
 387
 388 Kernel debugging
 389 =================
 390
 391 I have't done this myself so I can't really offer any advice.
 392 Remote debugging over serial lines works fine, but the kernel debugging
 393 code in here has not been tested in years.  Van Jacobson has
 394 better kernel debugging, but the UC lawyers won't let FSF have it.
 395
 396
 397 Remote debugging
 398 =================
 399
 400 The files m68k-stub.c, i386-stub.c, and sparc-stub.c are examples of
 401 remote stubs to be used with remote.c.  They are designed to run
 402 standalone on an m68k, i386, or SPARC cpu and communicate properly with
 403 the remote.c stub over a serial line.
 404
 405 The file rem-multi.shar contains a general stub that can probably
 406 run on various different flavors of unix to allow debugging over a
 407 serial line from one machine to another.
 408
 409 Some working remote interfaces for talking to existing ROM monitors
 410 are:
 411         remote-adapt.c   AMD 29000 "Adapt"
 412         remote-eb.c      AMD 29000 "EBMON"
 413         remote-es1800.c  Ericsson 1800 monitor
 414         remote-hms.c     Hitachi Micro Systems H8/300 monitor
 415         remote-mips.c    MIPS remote debugging protocol
 416         remote-mm.c      AMD 29000 "minimon"
 417         remote-nindy.c   Intel 960 "Nindy"
 418         remote-sim.c     Generalized simulator protocol
 419         remote-st2000.c  Tandem ST-2000 monitor
 420         remote-udi.c     AMD 29000 using the AMD "Universal Debug Interface"
 421         remote-vx.c      VxWorks realtime kernel
 422         remote-z8k.c     Zilog Z8000 simulator
 423
 424 Remote-vx.c and the vx-share subdirectory contain a remote interface for the
 425 VxWorks realtime kernel, which communicates over TCP using the Sun
 426 RPC library.  This would be a useful starting point for other remote-
 427 via-ethernet back ends.
 428
 429 Remote-udi.c and the 29k-share subdirectory contain a remote interface
 430 for AMD 29000 programs, which uses the AMD "Universal Debug Interface".
 431 This allows GDB to talk to software simulators, emulators, and/or bare
 432 hardware boards, via network or serial interfaces.  Note that GDB only
 433 provides an interface that speaks UDI, not a complete solution.  You
 434 will need something on the other end that also speaks UDI.
 435
 436
 437 Reporting Bugs
 438 ===============
 439
 440 The correct address for reporting bugs found in gdb is
 441 "bug-gdb@prep.ai.mit.edu".  Please email all bugs, and all requests for
 442 help with GDB, to that address.  Please include the GDB version number
 443 (e.g. gdb-4.9), and how you configured it (e.g. "sun4" or "mach386
 444 host, i586-intel-synopsys target").  If you include the banner that GDB
 445 prints when it starts up, that will give us enough information.
 446
 447 For more information on how/whether to report bugs, see the GDB Bugs
 448 section of the GDB manual (gdb/doc/gdb.texinfo).
 449
 450 Known bugs:
 451
 452   * Under Ultrix 4.2 (DECstation-3100) or Alphas under OSF/1, we have
 453     seen problems with backtraces after interrupting the inferior out
 454     of a read().  The problem is caused by ptrace() returning an
 455     incorrect value for the frame pointer register (register 15 or
 456     30).  As far as we can tell, this is a kernel problem.  Any help
 457     with this would be greatly appreciated.
 458
 459   * On the SPARC GDB reports incorrect values of struct arguments to
 460     functions, for the seventh and subsequent arguments.  We have been looking
 461     at this but no fix is available yet.
 462
 463   * On DECstations there are warnings about shift counts out of range in
 464     various BFD modules.  None of them is a cause for alarm, they are actually
 465     a result of bugs in the DECstation compiler.
 466
 467   * On Solaris (2.1, at least) using the "run" command when the program
 468     is already running restarts the program, but may leave a core dump
 469     from the previous execution in the current directory.  Other SVR4
 470     based systems don't seem to have this problem, using the same gdb
 471     source code.
 472
 473   * Notes for the DEC Alpha using OSF/1:
 474     The debugging output of native cc has two known problems; we view these
 475     as compiler bugs.
 476     The linker miscompacts symbol tables, which causes gdb to confuse the
 477     type of variables or results in `struct <illegal>' type outputs.
 478     dbx has the same problems with those executables.  A workaround is to
 479     specify -Wl,-b when linking, but that will increase the executable size
 480     considerably.
 481     If a structure has incomplete type in one file (e.g. "struct foo *"
 482     without a definition for "struct foo"), gdb will be unable to find the
 483     structure definition from another file.
 484     It has been reported that the Ultrix 4.3A compiler on decstations has the
 485     same problems.
 486
 487     If you intend to compile gdb with gcc-2.4.5, be warned that the file
 488     bfd/libbfd.c will be miscompiled due to a bug in gcc, you have
 489     to compile this file with native cc.  You will get many warnings from
 490     gcc while compiling gdb, but these can be ignored for now.  Again, these
 491     problems are Alpha-specific.
 492
 493 GDB can produce warnings about symbols that it does not understand.  By
 494 default, these warnings are disabled.  You can enable them by executing
 495 `set complaint 10' (which you can put in your ~/.gdbinit if you like).
 496 I recommend doing this if you are working on a compiler, assembler,
 497 linker, or gdb, since it will point out problems that you may be able
 498 to fix.  Warnings produced during symbol reading indicate some mismatch
 499 between the object file and GDB's symbol reading code.  In many cases,
 500 it's a mismatch between the specs for the object file format, and what
 501 the compiler actually outputs or the debugger actually understands.
 502
 503
 504 X Windows versus GDB
 505 =====================
 506
 507 There is an "xxgdb", which seems to work for simple operations,
 508 which was posted to comp.sources.x.
 509
 510 For those interested in auto display of source and the availability of
 511 an editor while debugging I suggest trying gdb-mode in gnu-emacs
 512 (Try typing M-x gdb RETURN).  Comments on this mode are welcome.
 513
 514
 515 Writing Code for GDB
 516 =====================
 517
 518 There is a lot of information about writing code for GDB in the
 519 internals manual, distributed with GDB in gdb/doc/gdbint.texinfo.  You
 520 can read it by hand, print it by using TeX and texinfo, or process it
 521 into an `info' file for use with Emacs' info mode or the standalone
 522 `info' program.  In particular, see the nodes Getting Started,
 523 Debugging GDB, New Architectures, Coding Style, Clean Design, and
 524 Submitting Patches.
 525
 526 If you are pondering writing anything but a short patch, especially
 527 take note of the information about copyrights in the node Submitting
 528 Patches.  It can take quite a while to get all the paperwork done, so
 529 we encourage you to start that process as soon as you decide you are
 530 planning to work on something, or at least well ahead of when you
 531 think you will be ready to submit the patches.
 532
 533
 534 GDB Testsuite
 535 =============
 536
 537 There is a dejagnu based testsuite available for testing your newly
 538 built gdb, or for regression testing gdb's with local modifications.
 539 The testsuite is distributed separately from the base gdb distribution
 540 for the convenience of people that wish to get either gdb or the testsuite
 541 separately.
 542
 543 The name of the testsuite is gdb-4.9-testsuite.tar.z.  You unpack it in the
 544 same directory in which you unpacked the base gdb distribution, and it
 545 will create and populate the directory gdb-4.9/gdb/testsuite.
 546
 547 Running the testsuite requires the prior installation of dejagnu, which
 548 should be available via ftp.  Once dejagnu is installed, you can run
 549 the tests in one of two ways:
 550
 551   (1)   cd gdb-4.9/gdb          (assuming you also unpacked gdb)
 552         make check
 553
 554 or
 555
 556   (2)   cd gdb-4.9/gdb/testsuite
 557         make            (builds the test executables)
 558         make site.exp   (builds the site specific file)
 559         runtest -tool gdb GDB=../gdb    (or GDB=<somepath> as appropriate)
 560
 561 The second method gives you slightly more control in case of problems with
 562 building one or more test executables, in case you wish to remove some
 563 test executables before running the tests, or if you are using the testsuite
 564 'standalone', without it being part of the gdb source tree.
 565
 566 See the dejagnu documentation for further details.
 567
 568 \f
 569 (this is for editing this file with GNU emacs)
 570 Local Variables:
 571 mode: text
 572 End: