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INFO-DIR-SECTION Programming & development tools.
START-INFO-DIR-ENTRY
* Gdb-Internals: (gdbint).      The GNU debugger's internals.
END-INFO-DIR-ENTRY

   This file documents the internals of the GNU debugger GDB.
Copyright 1990,1991,1992,1993,1994,1996,1998,1999,2000,2001,2002
Free Software Foundation, Inc.  Contributed by Cygnus Solutions.
Written by John Gilmore.  Second Edition by Stan Shebs.

   Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.1 or
any later version published by the Free Software Foundation; with no
Invariant Sections, with the Front-Cover Texts being "A GNU Manual,"
and with the Back-Cover Texts as in (a) below.

   (a) The FSF's Back-Cover Text is: "You have freedom to copy and
modify this GNU Manual, like GNU software.  Copies published by the Free
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File: gdbint.info,  Node: Releasing GDB,  Next: Testsuite,  Prev: Porting GDB,  Up: Top

Releasing GDB
*************

Versions and Branches
=====================

Version Identifiers
-------------------

   GDB's version is determined by the file `gdb/version.in'.

   GDB's mainline uses ISO dates to differentiate between versions.
The CVS repository uses YYYY-MM-DD-cvs while the corresponding snapshot
uses YYYYMMDD.

   GDB's release branch uses a slightly more complicated scheme.  When
the branch is first cut, the mainline version identifier is prefixed
with the MAJOR.MINOR from of the previous release series but with .90
appended.  As draft releases are drawn from the branch, the minor minor
number (.90) is incremented.  Once the first release (M.N) has been
made, the version prefix is updated to M.N.0.90 (dot zero, dot ninety).
Follow on releases have an incremented minor minor version number (.0).

   Using 5.1 (previous) and 5.2 (current), the example below
illustrates a typical sequence of version identifiers:

5.1.1
     final release from previous branch

2002-03-03-cvs
     main-line the day the branch is cut

5.1.90-2002-03-03-cvs
     corresponding branch version

5.1.91
     first draft release candidate

5.1.91-2002-03-17-cvs
     updated branch version

5.1.92
     second draft release candidate

5.1.92-2002-03-31-cvs
     updated branch version

5.1.93
     final release candidate (see below)

5.2
     official release

5.2.0.90-2002-04-07-cvs
     updated CVS branch version

5.2.1
     second official release

   Notes:

   * Minor minor minor draft release candidates such as 5.2.0.91 have
     been omitted from the example.  Such release candidates are,
     typically, never made.

   * For 5.1.93 the bziped tar ball `gdb-5.1.93.tar.bz2' is just the
     official `gdb-5.2.tar' renamed and compressed.

   To avoid version conflicts, vendors are expected to modify the file
`gdb/version.in' to include a vendor unique alphabetic identifier (an
official GDB release never uses alphabetic characters in its version
identifer).

   Since GDB does not make minor minor minor releases (e.g., 5.1.0.1)
the conflict between that and a minor minor draft release identifier
(e.g., 5.1.0.90) is avoided.

Branches
--------

   GDB draws a release series (5.2, 5.2.1, ...) from a single release
branch (gdb_5_2-branch).  Since minor minor minor releases (5.1.0.1)
are not made, the need to branch the release branch is avoided (it also
turns out that the effort required for such a a branch and release is
significantly greater than the effort needed to create a new release
from the head of the release branch).

   Releases 5.0 and 5.1 used branch and release tags of the form:

     gdb_N_M-YYYY-MM-DD-branchpoint
     gdb_N_M-YYYY-MM-DD-branch
     gdb_M_N-YYYY-MM-DD-release

   Release 5.2 is trialing the branch and release tags:

     gdb_N_M-YYYY-MM-DD-branchpoint
     gdb_N_M-branch
     gdb_M_N-YYYY-MM-DD-release

   _Pragmatics: The branchpoint and release tags need to identify when
a branch and release are made.  The branch tag, denoting the head of the
branch, does not have this criteria._

Branch Commit Policy
====================

   The branch commit policy is pretty slack.  GDB releases 5.0, 5.1 and
5.2 all used the below:

   * The `gdb/MAINTAINERS' file still holds.

   * Don't fix something on the branch unless/until it is also fixed in
     the trunk.  If this isn't possible, mentioning it in the
     `gdb/PROBLEMS' file is better than committing a hack.

   * When considering a patch for the branch, suggested criteria
     include: Does it fix a build?  Does it fix the sequence `break
     main; run' when debugging a static binary?

   * The further a change is from the core of GDB, the less likely the
     change will worry anyone (e.g., target specific code).

   * Only post a proposal to change the core of GDB after you've sent
     individual bribes to all the people listed in the `MAINTAINERS'
     file ;-)

   _Pragmatics: Provided updates are restricted to non-core
functionality there is little chance that a broken change will be fatal.
This means that changes such as adding a new architectures or (within
reason) support for a new host are considered acceptable._

Obsoleting code
===============

   Before anything else, poke the other developers (and around the
source code) to see if there is anything that can be removed from GDB
(an old target, an unused file).

   Obsolete code is identified by adding an `OBSOLETE' prefix to every
line.  Doing this means that it is easy to identify something that has
been obsoleted when greping through the sources.

   The process is done in stages -- this is mainly to ensure that the
wider GDB community has a reasonable opportunity to respond.  Remember,
everything on the Internet takes a week.

  1. Post the proposal on the GDB mailing list <gdb@sources.redhat.com>
     Creating a bug report to track the task's state, is also highly
     recommended.

  2. Wait a week or so.

  3. Post the proposal on the GDB Announcement mailing list
     <gdb-announce@sources.redhat.com>.

  4. Wait a week or so.

  5. Go through and edit all relevant files and lines so that they are
     prefixed with the word `OBSOLETE'.

  6. Wait until the next GDB version, containing this obsolete code,
     has been released.

  7. Remove the obsolete code.

_Maintainer note: While removing old code is regrettable it is
hopefully better for GDB's long term development.  Firstly it helps the
developers by removing code that is either no longer relevant or simply
wrong.  Secondly since it removes any history associated with the file
(effectively clearing the slate) the developer has a much freer hand
when it comes to fixing broken files._

Before the Branch
=================

   The most important objective at this stage is to find and fix simple
changes that become a pain to track once the branch is created.  For
instance, configuration problems that stop GDB from even building.  If
you can't get the problem fixed, document it in the `gdb/PROBLEMS' file.

Prompt for `gdb/NEWS'
---------------------

   People always forget.  Send a post reminding them but also if you
know something interesting happened add it yourself.  The `schedule'
script will mention this in its e-mail.

Review `gdb/README'
-------------------

   Grab one of the nightly snapshots and then walk through the
`gdb/README' looking for anything that can be improved.  The `schedule'
script will mention this in its e-mail.

Refresh any imported files.
---------------------------

   A number of files are taken from external repositories.  They
include:

   * `texinfo/texinfo.tex'

   * `config.guess' et. al. (see the top-level `MAINTAINERS' file)

   * `etc/standards.texi', `etc/make-stds.texi'

Check the ARI
-------------

   A.R.I. is an `awk' script (Awk Regression Index ;-) that checks for
a number of errors and coding conventions.  The checks include things
like using `malloc' instead of `xmalloc' and file naming problems.
There shouldn't be any regressions.

Review the bug data base
------------------------

   Close anything obviously fixed.

Check all cross targets build
-----------------------------

   The targets are listed in `gdb/MAINTAINERS'.

Cut the Branch
==============

Create the branch
-----------------

     $  u=5.1
     $  v=5.2
     $  V=`echo $v | sed 's/\./_/g'`
     $  D=`date -u +%Y-%m-%d`
     $  echo $u $V $D
     5.1 5_2 2002-03-03
     $  echo cvs -f -d :ext:sources.redhat.com:/cvs/src rtag \
     -D $D-gmt gdb_$V-$D-branchpoint insight+dejagnu
     cvs -f -d :ext:sources.redhat.com:/cvs/src rtag
     -D 2002-03-03-gmt gdb_5_2-2002-03-03-branchpoint insight+dejagnu
     $  ^echo ^^
     ...
     $  echo cvs -f -d :ext:sources.redhat.com:/cvs/src rtag \
     -b -r gdb_$V-$D-branchpoint gdb_$V-branch insight+dejagnu
     cvs -f -d :ext:sources.redhat.com:/cvs/src rtag \
     -b -r gdb_5_2-2002-03-03-branchpoint gdb_5_2-branch insight+dejagnu
     $  ^echo ^^
     ...
     $

   * by using `-D YYYY-MM-DD-gmt' the branch is forced to an exact
     date/time.

   * the trunk is first taged so that the branch point can easily be
     found

   * Insight (which includes GDB) and dejagnu are all tagged at the
     same time

   * `version.in' gets bumped to avoid version number conflicts

   * the reading of `.cvsrc' is disabled using `-f'

Update `version.in'
-------------------

     $  u=5.1
     $  v=5.2
     $  V=`echo $v | sed 's/\./_/g'`
     $  echo $u $v$V
     5.1 5_2
     $  cd /tmp
     $  echo cvs -f -d :ext:sources.redhat.com:/cvs/src co \
     -r gdb_$V-branch src/gdb/version.in
     cvs -f -d :ext:sources.redhat.com:/cvs/src co
      -r gdb_5_2-branch src/gdb/version.in
     $  ^echo ^^
     U src/gdb/version.in
     $  cd src/gdb
     $  echo $u.90-0000-00-00-cvs > version.in
     $  cat version.in
     5.1.90-0000-00-00-cvs
     $  cvs -f commit version.in

   * `0000-00-00' is used as a date to pump prime the version.in update
     mechanism

   * `.90' and the previous branch version are used as fairly arbitrary
     initial branch version number

Update the web and news pages
-----------------------------

   Something?

Tweak cron to track the new branch
----------------------------------

   The file `gdbadmin/cron/crontab' contains gdbadmin's cron table.
This file needs to be updated so that:

   * a daily timestamp is added to the file `version.in'

   * the new branch is included in the snapshot process

See the file `gdbadmin/cron/README' for how to install the updated cron
table.

   The file `gdbadmin/ss/README' should also be reviewed to reflect any
changes.  That file is copied to both the branch/ and current/ snapshot
directories.

Update the NEWS and README files
--------------------------------

   The `NEWS' file needs to be updated so that on the branch it refers
to _changes in the current release_ while on the trunk it also refers
to _changes since the current release_.

   The `README' file needs to be updated so that it refers to the
current release.

Post the branch info
--------------------

   Send an announcement to the mailing lists:

   * GDB Announcement mailing list <gdb-announce@sources.redhat.com>

   * GDB Discsussion mailing list <gdb@sources.redhat.com> and GDB
     Discsussion mailing list <gdb-testers@sources.redhat.com>

   _Pragmatics: The branch creation is sent to the announce list to
ensure that people people not subscribed to the higher volume discussion
list are alerted._

   The announcement should include:

   * the branch tag

   * how to check out the branch using CVS

   * the date/number of weeks until the release

   * the branch commit policy still holds.

Stabilize the branch
====================

   Something goes here.

Create a Release
================

   The process of creating and then making available a release is broken
down into a number of stages.  The first part addresses the technical
process of creating a releasable tar ball.  The later stages address the
process of releasing that tar ball.

   When making a release candidate just the first section is needed.

Create a release candidate
--------------------------

   The objective at this stage is to create a set of tar balls that can
be made available as a formal release (or as a less formal release
candidate).

Freeze the branch
.................

   Send out an e-mail notifying everyone that the branch is frozen to
<gdb-patches@sources.redhat.com>.

Establish a few defaults.
.........................

     $  b=gdb_5_2-branch
     $  v=5.2
     $  t=/sourceware/snapshot-tmp/gdbadmin-tmp
     $  echo $t/$b/$v
     /sourceware/snapshot-tmp/gdbadmin-tmp/gdb_5_2-branch/5.2
     $  mkdir -p $t/$b/$v
     $  cd $t/$b/$v
     $  pwd
     /sourceware/snapshot-tmp/gdbadmin-tmp/gdb_5_2-branch/5.2
     $  which autoconf
     /home/gdbadmin/bin/autoconf
     $

Notes:

   * Check the `autoconf' version carefully.  You want to be using the
     version taken from the `binutils' snapshot directory, which can be
     found at `ftp://sources.redhat.com/pub/binutils/'. It is very
     unlikely that a system installed version of `autoconf' (e.g.,
     `/usr/bin/autoconf') is correct.

Check out the relevant modules:
...............................

     $  for m in gdb insight dejagnu
     do
     ( mkdir -p $m && cd $m && cvs -q -f -d /cvs/src co -P -r $b $m )
     done
     $

Note:

   * The reading of `.cvsrc' is disabled (`-f') so that there isn't any
     confusion between what is written here and what your local `cvs'
     really does.

Update relevant files.
......................

`gdb/NEWS'
     Major releases get their comments added as part of the mainline.
     Minor releases should probably mention any significant bugs that
     were fixed.

     Don't forget to include the `ChangeLog' entry.

          $  emacs gdb/src/gdb/NEWS
          ...
          c-x 4 a
          ...
          c-x c-s c-x c-c
          $  cp gdb/src/gdb/NEWS insight/src/gdb/NEWS
          $  cp gdb/src/gdb/ChangeLog insight/src/gdb/ChangeLog

`gdb/README'
     You'll need to update:

        * the version

        * the update date

        * who did it

          $  emacs gdb/src/gdb/README
          ...
          c-x 4 a
          ...
          c-x c-s c-x c-c
          $  cp gdb/src/gdb/README insight/src/gdb/README
          $  cp gdb/src/gdb/ChangeLog insight/src/gdb/ChangeLog

     _Maintainer note: Hopefully the `README' file was reviewed before
     the initial branch was cut so just a simple substitute is needed
     to get it updated._

     _Maintainer note: Other projects generate `README' and `INSTALL'
     from the core documentation.  This might be worth pursuing._

`gdb/version.in'
          $  echo $v > gdb/src/gdb/version.in
          $  cat gdb/src/gdb/version.in
          5.2
          $  emacs gdb/src/gdb/version.in
          ...
          c-x 4 a
          ... Bump to version ...
          c-x c-s c-x c-c
          $  cp gdb/src/gdb/version.in insight/src/gdb/version.in
          $  cp gdb/src/gdb/ChangeLog insight/src/gdb/ChangeLog

`dejagnu/src/dejagnu/configure.in'
     Dejagnu is more complicated.  The version number is a parameter to
     `AM_INIT_AUTOMAKE'.  Tweak it to read something like gdb-5.1.91.

     Don't forget to re-generate `configure'.

     Don't forget to include a `ChangeLog' entry.

          $  emacs dejagnu/src/dejagnu/configure.in
          ...
          c-x 4 a
          ...
          c-x c-s c-x c-c
          $  ( cd  dejagnu/src/dejagnu && autoconf )

Do the dirty work
.................

   This is identical to the process used to create the daily snapshot.

     $  for m in gdb insight
     do
     ( cd $m/src && gmake -f Makefile.in $m.tar )
     done
     $  ( m=dejagnu; cd $m/src && gmake -f Makefile.in $m.tar.bz2 )

Check the source files
......................

   You're looking for files that have mysteriously disappeared.
`distclean' has the habit of deleting files it shouldn't.  Watch out
for the `version.in' update `cronjob'.

     $  ( cd gdb/src && cvs -f -q -n update )
     M djunpack.bat
     ? gdb-5.1.91.tar
     ? proto-toplev
     ... lots of generated files ...
     M gdb/ChangeLog
     M gdb/NEWS
     M gdb/README
     M gdb/version.in
     ... lots of generated files ...
     $

_Don't worry about the `gdb.info-??' or `gdb/p-exp.tab.c'.  They were
generated (and yes `gdb.info-1' was also generated only something
strange with CVS means that they didn't get supressed).  Fixing it
would be nice though._

Create compressed versions of the release
.........................................

     $  cp */src/*.tar .
     $  cp */src/*.bz2 .
     $  ls -F
     dejagnu/ dejagnu-gdb-5.2.tar.bz2 gdb/ gdb-5.2.tar insight/ insight-5.2.tar
     $  for m in gdb insight
     do
     bzip2 -v -9 -c $m-$v.tar > $m-$v.tar.bz2
     gzip -v -9 -c $m-$v.tar > $m-$v.tar.gz
     done
     $

Note:

   * A pipe such as `bunzip2 < xxx.bz2 | gzip -9 > xxx.gz' is not since,
     in that mode, `gzip' does not know the name of the file and, hence,
     can not include it in the compressed file.  This is also why the
     release process runs `tar' and `bzip2' as separate passes.

Sanity check the tar ball
-------------------------

   Pick a popular machine (Solaris/PPC?) and try the build on that.

     $  bunzip2 < gdb-5.2.tar.bz2 | tar xpf -
     $  cd gdb-5.2
     $  ./configure
     $  make
     ...
     $  ./gdb/gdb ./gdb/gdb
     GNU gdb 5.2
     ...
     (gdb)  b main
     Breakpoint 1 at 0x80732bc: file main.c, line 734.
     (gdb)  run
     Starting program: /tmp/gdb-5.2/gdb/gdb
     
     Breakpoint 1, main (argc=1, argv=0xbffff8b4) at main.c:734
     734       catch_errors (captured_main, &args, "", RETURN_MASK_ALL);
     (gdb)  print args
     $1 = {argc = 136426532, argv = 0x821b7f0}
     (gdb)

Make a release candidate available
----------------------------------

   If this is a release candidate then the only remaining steps are:

  1. Commit `version.in' and `ChangeLog'

  2. Tweak `version.in' (and `ChangeLog' to read L.M.N-0000-00-00-cvs
     so that the version update process can restart.

  3. Make the release candidate available in
     `ftp://sources.redhat.com/pub/gdb/snapshots/branch'

  4. Notify the relevant mailing lists ( <gdb@sources.redhat.com> and
     <gdb-testers@sources.redhat.com> that the candidate is available.

Make a formal release available
-------------------------------

   (And you thought all that was required was to post an e-mail.)

Install on sware
................

   Copy the new files to both the release and the old release directory:

     $  cp *.bz2 *.gz ~ftp/pub/gdb/old-releases/
     $  cp *.bz2 *.gz ~ftp/pub/gdb/releases

Clean up the releases directory so that only the most recent releases
are available (e.g. keep 5.2 and 5.2.1 but remove 5.1):

     $  cd ~ftp/pub/gdb/releases
     $  rm ...

Update the file `README' and `.message' in the releases directory:

     $  vi README
     ...
     $  rm -f .message
     $  ln README .message

Update the web pages.
.....................

`htdocs/download/ANNOUNCEMENT'
     This file, which is posted as the official announcement, includes:
        * General announcement

        * News.  If making an M.N.1 release, retain the news from
          earlier M.N release.

        * Errata

`htdocs/index.html'
`htdocs/news/index.html'
`htdocs/download/index.html'
     These files include:
        * announcement of the most recent release

        * news entry (remember to update both the top level and the
          news directory).
     These pages also need to be regenerate using `index.sh'.

`download/onlinedocs/'
     You need to find the magic command that is used to generate the
     online docs from the `.tar.bz2'.  The best way is to look in the
     output from one of the nightly `cron' jobs and then just edit
     accordingly.  Something like:

          $  ~/ss/update-web-docs \
           ~ftp/pub/gdb/releases/gdb-5.2.tar.bz2 \
           $PWD/www \
           /www/sourceware/htdocs/gdb/download/onlinedocs \
           gdb

`download/ari/'
     Just like the online documentation.  Something like:

          $  /bin/sh ~/ss/update-web-ari \
           ~ftp/pub/gdb/releases/gdb-5.2.tar.bz2 \
           $PWD/www \
           /www/sourceware/htdocs/gdb/download/ari \
           gdb

Shadow the pages onto gnu
.........................

   Something goes here.

Install the GDB tar ball on GNU
...............................

   At the time of writing, the GNU machine was `gnudist.gnu.org' in
`~ftp/gnu/gdb'.

Make the `ANNOUNCEMENT'
.......................

   Post the `ANNOUNCEMENT' file you created above to:

   * GDB Announcement mailing list <gdb-announce@sources.redhat.com>

   * General GNU Announcement list <info-gnu@gnu.org> (but delay it a
     day or so to let things get out)

   * GDB Bug Report mailing list <bug-gdb@gnu.org>

Cleanup
-------

   The release is out but you're still not finished.

Commit outstanding changes
..........................

   In particular you'll need to commit any changes to:

   * `gdb/ChangeLog'

   * `gdb/version.in'

   * `gdb/NEWS'

   * `gdb/README'

Tag the release
...............

   Something like:

     $  d=`date -u +%Y-%m-%d`
     $  echo $d
     2002-01-24
     $  ( cd insight/src/gdb && cvs -f -q update )
     $  ( cd insight/src && cvs -f -q tag gdb_5_2-$d-release )

   Insight is used since that contains more of the release than GDB
(`dejagnu' doesn't get tagged but I think we can live with that).

Mention the release on the trunk
................................

   Just put something in the `ChangeLog' so that the trunk also
indicates when the release was made.

Restart `gdb/version.in'
........................

   If `gdb/version.in' does not contain an ISO date such as
`2002-01-24' then the daily `cronjob' won't update it.  Having
committed all the release changes it can be set to
`5.2.0_0000-00-00-cvs' which will restart things (yes the `_' is
important - it affects the snapshot process).

   Don't forget the `ChangeLog'.

Merge into trunk
................

   The files committed to the branch may also need changes merged into
the trunk.

Revise the release schedule
...........................

   Post a revised release schedule to GDB Discussion List
<gdb@sources.redhat.com> with an updated announcement.  The schedule
can be generated by running:

     $  ~/ss/schedule `date +%s` schedule

The first parameter is approximate date/time in seconds (from the epoch)
of the most recent release.

   Also update the schedule `cronjob'.

Post release
============

   Remove any `OBSOLETE' code.


File: gdbint.info,  Node: Testsuite,  Next: Hints,  Prev: Releasing GDB,  Up: Top

Testsuite
*********

   The testsuite is an important component of the GDB package.  While
it is always worthwhile to encourage user testing, in practice this is
rarely sufficient; users typically use only a small subset of the
available commands, and it has proven all too common for a change to
cause a significant regression that went unnoticed for some time.

   The GDB testsuite uses the DejaGNU testing framework.  DejaGNU is
built using `Tcl' and `expect'.  The tests themselves are calls to
various `Tcl' procs; the framework runs all the procs and summarizes
the passes and fails.

Using the Testsuite
===================

   To run the testsuite, simply go to the GDB object directory (or to
the testsuite's objdir) and type `make check'.  This just sets up some
environment variables and invokes DejaGNU's `runtest' script.  While
the testsuite is running, you'll get mentions of which test file is in
use, and a mention of any unexpected passes or fails.  When the
testsuite is finished, you'll get a summary that looks like this:

                     === gdb Summary ===
     
     # of expected passes            6016
     # of unexpected failures        58
     # of unexpected successes       5
     # of expected failures          183
     # of unresolved testcases       3
     # of untested testcases         5

   The ideal test run consists of expected passes only; however, reality
conspires to keep us from this ideal.  Unexpected failures indicate
real problems, whether in GDB or in the testsuite.  Expected failures
are still failures, but ones which have been decided are too hard to
deal with at the time; for instance, a test case might work everywhere
except on AIX, and there is no prospect of the AIX case being fixed in
the near future.  Expected failures should not be added lightly, since
you may be masking serious bugs in GDB.  Unexpected successes are
expected fails that are passing for some reason, while unresolved and
untested cases often indicate some minor catastrophe, such as the
compiler being unable to deal with a test program.

   When making any significant change to GDB, you should run the
testsuite before and after the change, to confirm that there are no
regressions.  Note that truly complete testing would require that you
run the testsuite with all supported configurations and a variety of
compilers; however this is more than really necessary.  In many cases
testing with a single configuration is sufficient.  Other useful
options are to test one big-endian (Sparc) and one little-endian (x86)
host, a cross config with a builtin simulator (powerpc-eabi, mips-elf),
or a 64-bit host (Alpha).

   If you add new functionality to GDB, please consider adding tests
for it as well; this way future GDB hackers can detect and fix their
changes that break the functionality you added.  Similarly, if you fix
a bug that was not previously reported as a test failure, please add a
test case for it.  Some cases are extremely difficult to test, such as
code that handles host OS failures or bugs in particular versions of
compilers, and it's OK not to try to write tests for all of those.

Testsuite Organization
======================

   The testsuite is entirely contained in `gdb/testsuite'.  While the
testsuite includes some makefiles and configury, these are very minimal,
and used for little besides cleaning up, since the tests themselves
handle the compilation of the programs that GDB will run.  The file
`testsuite/lib/gdb.exp' contains common utility procs useful for all
GDB tests, while the directory `testsuite/config' contains
configuration-specific files, typically used for special-purpose
definitions of procs like `gdb_load' and `gdb_start'.

   The tests themselves are to be found in `testsuite/gdb.*' and
subdirectories of those.  The names of the test files must always end
with `.exp'.  DejaGNU collects the test files by wildcarding in the
test directories, so both subdirectories and individual files get
chosen and run in alphabetical order.

   The following table lists the main types of subdirectories and what
they are for.  Since DejaGNU finds test files no matter where they are
located, and since each test file sets up its own compilation and
execution environment, this organization is simply for convenience and
intelligibility.

`gdb.base'
     This is the base testsuite.  The tests in it should apply to all
     configurations of GDB (but generic native-only tests may live
     here).  The test programs should be in the subset of C that is
     valid K&R, ANSI/ISO, and C++ (`#ifdef's are allowed if necessary,
     for instance for prototypes).

`gdb.LANG'
     Language-specific tests for any language LANG besides C.  Examples
     are `gdb.c++' and `gdb.java'.

`gdb.PLATFORM'
     Non-portable tests.  The tests are specific to a specific
     configuration (host or target), such as HP-UX or eCos.  Example is
     `gdb.hp', for HP-UX.

`gdb.COMPILER'
     Tests specific to a particular compiler.  As of this writing (June
     1999), there aren't currently any groups of tests in this category
     that couldn't just as sensibly be made platform-specific, but one
     could imagine a `gdb.gcc', for tests of GDB's handling of GCC
     extensions.

`gdb.SUBSYSTEM'
     Tests that exercise a specific GDB subsystem in more depth.  For
     instance, `gdb.disasm' exercises various disassemblers, while
     `gdb.stabs' tests pathways through the stabs symbol reader.

Writing Tests
=============

   In many areas, the GDB tests are already quite comprehensive; you
should be able to copy existing tests to handle new cases.

   You should try to use `gdb_test' whenever possible, since it
includes cases to handle all the unexpected errors that might happen.
However, it doesn't cost anything to add new test procedures; for
instance, `gdb.base/exprs.exp' defines a `test_expr' that calls
`gdb_test' multiple times.

   Only use `send_gdb' and `gdb_expect' when absolutely necessary, such
as when GDB has several valid responses to a command.

   The source language programs do _not_ need to be in a consistent
style.  Since GDB is used to debug programs written in many different
styles, it's worth having a mix of styles in the testsuite; for
instance, some GDB bugs involving the display of source lines would
never manifest themselves if the programs used GNU coding style
uniformly.


File: gdbint.info,  Node: Hints,  Next: GNU Free Documentation License,  Prev: Testsuite,  Up: Top

Hints
*****

   Check the `README' file, it often has useful information that does
not appear anywhere else in the directory.

* Menu:

* Getting Started::             Getting started working on GDB
* Debugging GDB::               Debugging GDB with itself


File: gdbint.info,  Node: Getting Started,  Up: Hints

Getting Started
===============

   GDB is a large and complicated program, and if you first starting to
work on it, it can be hard to know where to start.  Fortunately, if you
know how to go about it, there are ways to figure out what is going on.

   This manual, the GDB Internals manual, has information which applies
generally to many parts of GDB.

   Information about particular functions or data structures are
located in comments with those functions or data structures.  If you
run across a function or a global variable which does not have a
comment correctly explaining what is does, this can be thought of as a
bug in GDB; feel free to submit a bug report, with a suggested comment
if you can figure out what the comment should say.  If you find a
comment which is actually wrong, be especially sure to report that.

   Comments explaining the function of macros defined in host, target,
or native dependent files can be in several places.  Sometimes they are
repeated every place the macro is defined.  Sometimes they are where the
macro is used.  Sometimes there is a header file which supplies a
default definition of the macro, and the comment is there.  This manual
also documents all the available macros.

   Start with the header files.  Once you have some idea of how GDB's
internal symbol tables are stored (see `symtab.h', `gdbtypes.h'), you
will find it much easier to understand the code which uses and creates
those symbol tables.

   You may wish to process the information you are getting somehow, to
enhance your understanding of it.  Summarize it, translate it to another
language, add some (perhaps trivial or non-useful) feature to GDB, use
the code to predict what a test case would do and write the test case
and verify your prediction, etc.  If you are reading code and your eyes
are starting to glaze over, this is a sign you need to use a more active
approach.

   Once you have a part of GDB to start with, you can find more
specifically the part you are looking for by stepping through each
function with the `next' command.  Do not use `step' or you will
quickly get distracted; when the function you are stepping through
calls another function try only to get a big-picture understanding
(perhaps using the comment at the beginning of the function being
called) of what it does.  This way you can identify which of the
functions being called by the function you are stepping through is the
one which you are interested in.  You may need to examine the data
structures generated at each stage, with reference to the comments in
the header files explaining what the data structures are supposed to
look like.

   Of course, this same technique can be used if you are just reading
the code, rather than actually stepping through it.  The same general
principle applies--when the code you are looking at calls something
else, just try to understand generally what the code being called does,
rather than worrying about all its details.

   A good place to start when tracking down some particular area is with
a command which invokes that feature.  Suppose you want to know how
single-stepping works.  As a GDB user, you know that the `step' command
invokes single-stepping.  The command is invoked via command tables
(see `command.h'); by convention the function which actually performs
the command is formed by taking the name of the command and adding
`_command', or in the case of an `info' subcommand, `_info'.  For
example, the `step' command invokes the `step_command' function and the
`info display' command invokes `display_info'.  When this convention is
not followed, you might have to use `grep' or `M-x tags-search' in
emacs, or run GDB on itself and set a breakpoint in `execute_command'.

   If all of the above fail, it may be appropriate to ask for
information on `bug-gdb'.  But _never_ post a generic question like "I
was wondering if anyone could give me some tips about understanding
GDB"--if we had some magic secret we would put it in this manual.
Suggestions for improving the manual are always welcome, of course.


File: gdbint.info,  Node: Debugging GDB,  Up: Hints

Debugging GDB with itself
=========================

   If GDB is limping on your machine, this is the preferred way to get
it fully functional.  Be warned that in some ancient Unix systems, like
Ultrix 4.2, a program can't be running in one process while it is being
debugged in another.  Rather than typing the command `./gdb ./gdb',
which works on Suns and such, you can copy `gdb' to `gdb2' and then
type `./gdb ./gdb2'.

   When you run GDB in the GDB source directory, it will read a
`.gdbinit' file that sets up some simple things to make debugging gdb
easier.  The `info' command, when executed without a subcommand in a
GDB being debugged by gdb, will pop you back up to the top level gdb.
See `.gdbinit' for details.

   If you use emacs, you will probably want to do a `make TAGS' after
you configure your distribution; this will put the machine dependent
routines for your local machine where they will be accessed first by
`M-.'

   Also, make sure that you've either compiled GDB with your local cc,
or have run `fixincludes' if you are compiling with gcc.

Submitting Patches
==================

   Thanks for thinking of offering your changes back to the community of
GDB users.  In general we like to get well designed enhancements.
Thanks also for checking in advance about the best way to transfer the
changes.

   The GDB maintainers will only install "cleanly designed" patches.
This manual summarizes what we believe to be clean design for GDB.

   If the maintainers don't have time to put the patch in when it
arrives, or if there is any question about a patch, it goes into a
large queue with everyone else's patches and bug reports.

   The legal issue is that to incorporate substantial changes requires a
copyright assignment from you and/or your employer, granting ownership
of the changes to the Free Software Foundation.  You can get the
standard documents for doing this by sending mail to `gnu@gnu.org' and
asking for it.  We recommend that people write in "All programs owned
by the Free Software Foundation" as "NAME OF PROGRAM", so that changes
in many programs (not just GDB, but GAS, Emacs, GCC, etc) can be
contributed with only one piece of legalese pushed through the
bureaucracy and filed with the FSF.  We can't start merging changes
until this paperwork is received by the FSF (their rules, which we
follow since we maintain it for them).

   Technically, the easiest way to receive changes is to receive each
feature as a small context diff or unidiff, suitable for `patch'.  Each
message sent to me should include the changes to C code and header
files for a single feature, plus `ChangeLog' entries for each directory
where files were modified, and diffs for any changes needed to the
manuals (`gdb/doc/gdb.texinfo' or `gdb/doc/gdbint.texinfo').  If there
are a lot of changes for a single feature, they can be split down into
multiple messages.

   In this way, if we read and like the feature, we can add it to the
sources with a single patch command, do some testing, and check it in.
If you leave out the `ChangeLog', we have to write one.  If you leave
out the doc, we have to puzzle out what needs documenting.  Etc., etc.

   The reason to send each change in a separate message is that we will
not install some of the changes.  They'll be returned to you with
questions or comments.  If we're doing our job correctly, the message
back to you will say what you have to fix in order to make the change
acceptable.  The reason to have separate messages for separate features
is so that the acceptable changes can be installed while one or more
changes are being reworked.  If multiple features are sent in a single
message, we tend to not put in the effort to sort out the acceptable
changes from the unacceptable, so none of the features get installed
until all are acceptable.

   If this sounds painful or authoritarian, well, it is.  But we get a
lot of bug reports and a lot of patches, and many of them don't get
installed because we don't have the time to finish the job that the bug
reporter or the contributor could have done.  Patches that arrive
complete, working, and well designed, tend to get installed on the day
they arrive.  The others go into a queue and get installed as time
permits, which, since the maintainers have many demands to meet, may not
be for quite some time.

   Please send patches directly to the GDB maintainers
<gdb-patches@sources.redhat.com>.

Obsolete Conditionals
=====================

   Fragments of old code in GDB sometimes reference or set the following
configuration macros.  They should not be used by new code, and old uses
should be removed as those parts of the debugger are otherwise touched.

`STACK_END_ADDR'
     This macro used to define where the end of the stack appeared, for
     use in interpreting core file formats that don't record this
     address in the core file itself.  This information is now
     configured in BFD, and GDB gets the info portably from there.  The
     values in GDB's configuration files should be moved into BFD
     configuration files (if needed there), and deleted from all of
     GDB's config files.

     Any `FOO-xdep.c' file that references STACK_END_ADDR is so old
     that it has never been converted to use BFD.  Now that's old!