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                     README for gdb-5.0 release

                Updated 11 May 2000 by Andrew Cagney

This is GDB, the GNU source-level debugger.

A summary of new features is in the file `NEWS'.

See the GDB home page at http://sourceware.cygnus.com/gdb/ for up to

date release information, mailing list links and archives, etc.

Unpacking and Installation -- quick overview

==========================

   In this release, the GDB debugger sources, the generic GNU include

files, the BFD ("binary file description") library, the readline

library, and other libraries all have directories of their own

underneath the gdb-5.0 directory.  The idea is that a variety of GNU

tools can share a common copy of these things.  Be aware of variation

over time--for example don't try to build gdb with a copy of bfd from

a release other than the gdb release (such as a binutils or gas

release), especially if the releases are more than a few weeks apart.

Configuration scripts and makefiles exist to cruise up and down this

directory tree and automatically build all the pieces in the right

order.

   When you unpack the gdb-5.0.tar.gz file, you'll find a directory

called `gdb-5.0', which contains:

  COPYING       config.if     install-sh     mmalloc         readline

  COPYING.LIB   config.sub    intl           move-if-change  sim

  Makefile.in   configure     libiberty      mpw-README      symlink-tree

  README        configure.in  ltconfig       mpw-build.in    texinfo

  bfd           djunpack.bat  ltmain.sh      mpw-config.in   utils

  config        etc           md5.sum        mpw-configure   ylwrap

  config-ml.in  gdb           missing        mpw-install

  config.guess  include       mkinstalldirs  opcodes

You can build GDB right in the source directory:

        cd gdb-5.0

        ./configure

        make

        cp gdb/gdb /usr/local/bin/gdb   (or wherever you want)

However, we recommend that an empty directory be used instead.

This way you do not clutter your source tree with binary files

and will be able to create different builds with different

configuration options.

You can build GDB in any empty build directory:

     mkdir build

     cd build

     /gdb-5.0/configure

     make

(Building GDB with DJGPP tools for MS-DOS/MS-Windows is slightly

different; see the file gdb-5.0/gdb/config/djgpp/README for details.)

   This will configure and build all the libraries as well as GDB.  If

`configure' can't determine your system type, specify one as its

argument, e.g., `./configure sun4' or `./configure decstation'.

   If you get compiler errors during this stage, see the `Reporting

Bugs' section below; there are a few known problems.

   GDB requires an ISO-C (ANSI C) compiler.  If you do not have an

ISO-C compiler for your system, you may be able to download and

install the GNU CC compiler.  It is available via anonymous FTP from

the directory `ftp://ftp.gnu.org/pub/gnu/gcc'.

   GDB can be used as a cross-debugger, running on a machine of one

type while debugging a program running on a machine of another type.

See below.

More Documentation

******************

   All the documentation for GDB comes as part of the machine-readable

distribution.  The documentation is written in Texinfo format, which

is a documentation system that uses a single source file to produce

both on-line information and a printed manual.  You can use one of the

Info formatting commands to create the on-line version of the

documentation and TeX (or `texi2roff') to typeset the printed version.

   GDB includes an already formatted copy of the on-line Info version

of this manual in the `gdb/doc' subdirectory.  The main Info file is

`gdb-5.0/gdb/doc/gdb.info', and it refers to subordinate files

matching `gdb.info*' in the same directory.  If necessary, you can

print out these files, or read them with any editor; but they are

easier to read using the `info' subsystem in GNU Emacs or the

standalone `info' program, available as part of the GNU Texinfo

distribution.

   If you want to format these Info files yourself, you need one of the

Info formatting programs, such as `texinfo-format-buffer' or

`makeinfo'.

   If you have `makeinfo' installed, and are in the top level GDB

source directory (`gdb-5.0', in the case of version 5.0), you can make

the Info file by typing:

     cd gdb/doc

     make info

   If you want to typeset and print copies of this manual, you need

TeX, a program to print its DVI output files, and `texinfo.tex', the

Texinfo definitions file.  This file is included in the GDB

distribution, in the directory `gdb-5.0/texinfo'.

   TeX is a typesetting program; it does not print files directly, but

produces output files called DVI files.  To print a typeset document,

you need a program to print DVI files.  If your system has TeX

installed, chances are it has such a program.  The precise command to

use depends on your system; `lpr -d' is common; another (for PostScript

devices) is `dvips'.  The DVI print command may require a file name

without any extension or a `.dvi' extension.

   TeX also requires a macro definitions file called `texinfo.tex'.

This file tells TeX how to typeset a document written in Texinfo

format.  On its own, TeX cannot read, much less typeset a Texinfo file.

 `texinfo.tex' is distributed with GDB and is located in the

`gdb-5.0/texinfo' directory.

   If you have TeX and a DVI printer program installed, you can typeset

and print this manual.  First switch to the the `gdb' subdirectory of

the main source directory (for example, to `gdb-5.0/gdb') and then type:

     make gdb.dvi

Installing GDB

**************

   GDB comes with a `configure' script that automates the process of

preparing GDB for installation; you can then use `make' to build the

`gdb' program.

   The GDB distribution includes all the source code you need for GDB in

a single directory, whose name is usually composed by appending the

version number to `gdb'.

   For example, the GDB version 5.0 distribution is in the `gdb-5.0'

directory.  That directory contains:

`gdb-5.0/{COPYING,COPYING.LIB}'

     Standard GNU license files.  Please read them.

`gdb-5.0/bfd'

     source for the Binary File Descriptor library

`gdb-5.0/config*'

     script for configuring GDB, along with other support files

`gdb-5.0/gdb'

     the source specific to GDB itself

`gdb-5.0/include'

     GNU include files

`gdb-5.0/libiberty'

     source for the `-liberty' free software library

`gdb-5.0/mmalloc'

     source for the GNU memory-mapped malloc package

`gdb-5.0/opcodes'

     source for the library of opcode tables and disassemblers

`gdb-5.0/readline'

     source for the GNU command-line interface

     NOTE:  The readline library is compiled for use by GDB, but will

     not be installed on your system when "make install" is issued.

`gdb-5.0/sim'

     source for some simulators (ARM, D10V, SPARC, M32R, MIPS, PPC, V850, etc)

`gdb-5.0/intl'

     source for the GNU gettext library, for internationalization.

     This is slightly modified from the standalone gettext

     distribution you can get from GNU.

`gdb-5.0/texinfo'

     The `texinfo.tex' file, which you need in order to make a printed

     manual using TeX.

`gdb-5.0/etc'

     Coding standards, useful files for editing GDB, and other

     miscellanea.

`gdb-5.0/utils'

     A grab bag of random utilities.

   Note: the following instructions are for building GDB on Unix or

Unix-like systems.  Instructions for building with DJGPP for

MS-DOS/MS-Windows are in the file gdb/config/djgpp/README.

   The simplest way to configure and build GDB is to run `configure'

from the `gdb-VERSION-NUMBER' source directory, which in this example

is the `gdb-5.0' directory.

   First switch to the `gdb-VERSION-NUMBER' source directory if you are

not already in it; then run `configure'.

   For example:

     cd gdb-5.0

     ./configure

     make

   Running `configure' followed by `make' builds the `bfd',

`readline', `mmalloc', and `libiberty' libraries, then `gdb' itself.

The configured source files, and the binaries, are left in the

corresponding source directories.

   `configure' is a Bourne-shell (`/bin/sh') script; if your system

does not recognize this automatically when you run a different shell,

you may need to run `sh' on it explicitly:

     sh configure

   If you run `configure' from a directory that contains source

directories for multiple libraries or programs, such as the `gdb-5.0'

source directory for version 5.0, `configure' creates configuration

files for every directory level underneath (unless you tell it not to,

with the `--norecursion' option).

   You can run the `configure' script from any of the subordinate

directories in the GDB distribution, if you only want to configure that

subdirectory; but be sure to specify a path to it.

   For example, with version 5.0, type the following to configure only

the `bfd' subdirectory:

     cd gdb-5.0/bfd

     ../configure

   You can install `gdb' anywhere; it has no hardwired paths. However,

you should make sure that the shell on your path (named by the `SHELL'

environment variable) is publicly readable.  Remember that GDB uses the

shell to start your program--some systems refuse to let GDB debug child

processes whose programs are not readable.

Compiling GDB in another directory

==================================

   If you want to run GDB versions for several host or target machines,

you need a different `gdb' compiled for each combination of host and

target.  `configure' is designed to make this easy by allowing you to

generate each configuration in a separate subdirectory, rather than in

the source directory.  If your `make' program handles the `VPATH'

feature correctly (GNU `make' and SunOS 'make' are two that should),

running `make' in each of these directories builds the `gdb' program

specified there.

   To build `gdb' in a separate directory, run `configure' with the

`--srcdir' option to specify where to find the source. (You also need

to specify a path to find `configure' itself from your working

directory.  If the path to `configure' would be the same as the

argument to `--srcdir', you can leave out the `--srcdir' option; it

will be assumed.)

   For example, with version 5.0, you can build GDB in a separate

directory for a Sun 4 like this:

     cd gdb-5.0

     mkdir ../gdb-sun4

     cd ../gdb-sun4

     ../gdb-5.0/configure

     make

   When `configure' builds a configuration using a remote source

directory, it creates a tree for the binaries with the same structure

(and using the same names) as the tree under the source directory.  In

the example, you'd find the Sun 4 library `libiberty.a' in the

directory `gdb-sun4/libiberty', and GDB itself in `gdb-sun4/gdb'.

   One popular reason to build several GDB configurations in separate

directories is to configure GDB for cross-compiling (where GDB runs on

one machine--the host--while debugging programs that run on another

machine--the target).  You specify a cross-debugging target by giving

the `--target=TARGET' option to `configure'.

   When you run `make' to build a program or library, you must run it

in a configured directory--whatever directory you were in when you

called `configure' (or one of its subdirectories).

   The `Makefile' that `configure' generates in each source directory

also runs recursively.  If you type `make' in a source directory such

as `gdb-5.0' (or in a separate configured directory configured with

`--srcdir=PATH/gdb-5.0'), you will build all the required libraries,

and then build GDB.

   When you have multiple hosts or targets configured in separate

directories, you can run `make' on them in parallel (for example, if

they are NFS-mounted on each of the hosts); they will not interfere

with each other.

Specifying names for hosts and targets

======================================

   The specifications used for hosts and targets in the `configure'

script are based on a three-part naming scheme, but some short

predefined aliases are also supported.  The full naming scheme encodes

three pieces of information in the following pattern:

     ARCHITECTURE-VENDOR-OS

   For example, you can use the alias `sun4' as a HOST argument or in a

`--target=TARGET' option.  The equivalent full name is

`sparc-sun-sunos4'.

   The `configure' script accompanying GDB does not provide any query

facility to list all supported host and target names or aliases.

`configure' calls the Bourne shell script `config.sub' to map

abbreviations to full names; you can read the script, if you wish, or

you can use it to test your guesses on abbreviations--for example:

     % sh config.sub sun4

     sparc-sun-sunos4.1.1

     % sh config.sub sun3

     m68k-sun-sunos4.1.1

     % sh config.sub decstation

     mips-dec-ultrix4.2

     % sh config.sub hp300bsd

     m68k-hp-bsd

     % sh config.sub i386v

     i386-pc-sysv

     % sh config.sub i786v

     Invalid configuration `i786v': machine `i786v' not recognized

`config.sub' is also distributed in the GDB source directory

(`gdb-5.0', for version 5.0).

`configure' options

===================

   Here is a summary of the `configure' options and arguments that are

most often useful for building GDB.  `configure' also has several other

options not listed here.  *note : (configure.info)What Configure Does,

for a full explanation of `configure'.

     configure [--help]

               [--prefix=DIR]

               [--srcdir=PATH]

               [--norecursion] [--rm]

               [--enable-build-warnings]

               [--target=TARGET]

               [--host=HOST]

               [HOST]

You may introduce options with a single `-' rather than `--' if you

prefer; but you may abbreviate option names if you use `--'.

`--help'

     Display a quick summary of how to invoke `configure'.

`-prefix=DIR'

     Configure the source to install programs and files under directory

     `DIR'.

`--srcdir=PATH'

     *Warning: using this option requires GNU `make', or another `make'

     that compatibly implements the `VPATH' feature.*

     Use this option to make configurations in directories separate

     from the GDB source directories.  Among other things, you can use

     this to build (or maintain) several configurations simultaneously,

     in separate directories.  `configure' writes configuration

     specific files in the current directory, but arranges for them to

     use the source in the directory PATH.  `configure' will create

     directories under the working directory in parallel to the source

     directories below PATH.

`--norecursion'

     Configure only the directory level where `configure' is executed;

     do not propagate configuration to subdirectories.

`--rm'

     Remove the configuration that the other arguments specify.

`--enable-build-warnings'

     When building the GDB sources, ask the compiler to warn about any

     code which looks even vaguely suspicious.  You should only using

     this feature if you're compiling with GNU CC.  It passes the

     following flags:

        -Wimplicit

        -Wreturn-type

        -Wcomment

        -Wtrigraphs

        -Wformat

        -Wparentheses

        -Wpointer-arith

`--target=TARGET'

     Configure GDB for cross-debugging programs running on the specified

     TARGET.  Without this option, GDB is configured to debug programs

     that run on the same machine (HOST) as GDB itself.

     There is no convenient way to generate a list of all available

     targets.

`--host=HOST'

     Configure GDB to run on the specified HOST.

     There is no convenient way to generate a list of all available

     hosts.

`HOST ...'

     Same as `--host=HOST'.  If you omit this, GDB will guess; it's

     quite accurate.

`configure' accepts other options, for compatibility with configuring

other GNU tools recursively; but these are the only options that affect

GDB or its supporting libraries.

Languages other than C

=======================

See the GDB manual (gdb/doc/gdb.texinfo) for information on this.

Kernel debugging

=================

   Remote debugging over serial lines works fine, but the kernel

debugging code in here has not been tested in years.  Van Jacobson has

better kernel debugging, but the UC lawyers won't let FSF have it.

Remote debugging

=================

   The files m68k-stub.c, i386-stub.c, and sparc-stub.c are examples

of remote stubs to be used with remote.c.  They are designed to run

standalone on an m68k, i386, or SPARC cpu and communicate properly

with the remote.c stub over a serial line.

   The directory gdb/gdbserver/ contains `gdbserver', a program that

allows remote debugging for Unix applications.  gdbserver is only

supported for some native configurations, including Sun 3, Sun 4, and

Linux.

   There are a number of remote interfaces for talking to existing ROM

monitors and other hardware:

        remote-adapt.c   AMD 29000 "Adapt"

        remote-array.c   Array Tech RAID controller

        remote-bug.c     Motorola BUG monitor

        remote-e7000.c   Hitachi E7000 ICE

        remote-eb.c      AMD 29000 "EBMON"

        remote-es.c      Ericsson 1800 monitor

        remote-est.c     EST emulator

        remote-hms.c     Hitachi Micro Systems H8/300 monitor

        remote-mips.c    MIPS remote debugging protocol

        remote-mm.c      AMD 29000 "minimon"

        remote-nindy.c   Intel 960 "Nindy"

        remote-nrom.c    NetROM ROM emulator

        remote-os9k.c    PC running OS/9000

        remote-rdi.c     ARM with Angel monitor

        remote-rdp.c     ARM with Demon monitor

        remote-sds.c     PowerPC SDS monitor

        remote-sim.c     Generalized simulator protocol

        remote-st.c      Tandem ST-2000 monitor

        remote-udi.c     AMD 29000 using the AMD "Universal Debug Interface"

        remote-vx.c      VxWorks realtime kernel

   Remote-vx.c and the vx-share subdirectory contain a remote

interface for the VxWorks realtime kernel, which communicates over TCP

using the Sun RPC library.  This would be a useful starting point for

other remote- via-ethernet back ends.

   Remote-udi.c and the 29k-share subdirectory contain a remote

interface for AMD 29000 programs, which uses the AMD "Universal Debug

Interface".  This allows GDB to talk to software simulators,

emulators, and/or bare hardware boards, via network or serial

interfaces.  Note that GDB only provides an interface that speaks UDI,

not a complete solution.  You will need something on the other end

that also speaks UDI.

Reporting Bugs

===============

   The correct address for reporting bugs found in gdb is

"bug-gdb@gnu.org".  Please email all bugs, and all requests for help

with GDB, to that address.  Please include the GDB version number

(e.g., gdb-5.0), and how you configured it (e.g., "sun4" or "mach386

host, i586-intel-synopsys target").  Since GDB now supports so many

different configurations, it is important that you be precise about

this.  If at all possible, you should include the actual banner that

GDB prints when it starts up, or failing that, the actual configure

command that you used when configuring GDB.

   For more information on how/whether to report bugs, see the GDB

Bugs section of the GDB manual (gdb/doc/gdb.texinfo) or the

gdb/CONTRIBUTE file.

Known bugs:

  * Under Ultrix 4.2 (DECstation-3100) or Alphas under OSF/1, we have

    seen problems with backtraces after interrupting the inferior out

    of a read().  The problem is caused by ptrace() returning an

    incorrect value for the frame pointer register (register 15 or

    30).  As far as we can tell, this is a kernel problem.  Any help

    with this would be greatly appreciated.

  * Under Ultrix 4.4 (DECstation-3100), setting the TERMCAP environment

    variable to a string without a trailing ':' can cause GDB to dump

    core upon startup.  Although the core file makes it look as though

    GDB code failed, the crash actually occurs within a call to the

    termcap library function tgetent().  The problem can be solved by

    using the GNU Termcap library.

    Alphas running OSF/1 (versions 1.0 through 2.1) have the same buggy

    termcap code, but GDB behaves strangely rather than crashing.

  * On DECstations there are warnings about shift counts out of range in

    various BFD modules.  None of them is a cause for alarm, they are actually

    a result of bugs in the DECstation compiler.

  * Notes for the DEC Alpha using OSF/1:

    The debugging output of native cc has two known problems; we view these

    as compiler bugs.

    The linker miscompacts symbol tables, which causes gdb to confuse the

    type of variables or results in `struct ' type outputs.

    dbx has the same problems with those executables.  A workaround is to

    specify -Wl,-b when linking, but that will increase the executable size

    considerably.

    If a structure has incomplete type in one file (e.g., "struct foo *"

    without a definition for "struct foo"), gdb will be unable to find the

    structure definition from another file.

    It has been reported that the Ultrix 4.3A compiler on decstations has the

    same problems.

  * Notes for Solaris 2.x, using the SPARCworks cc compiler:

    You have to compile your program with the -xs option of the SPARCworks

    compiler to be able to debug your program with gdb.

    Under Solaris 2.3 you also need patch 101409-03 (Jumbo linker patch).

    Under Solaris 2.2, if you have patch 101052 installed, make sure

    that it is at least at revision 101052-06.

  * Under Irix 5 for SGIs, you must have installed the `compiler_dev.hdr'

    subsystem that is on the IDO CD, otherwise you will get complaints

    that certain files such as `/usr/include/syms.h' cannot be found.

  * Under Irix 6 you must build with GCC.  The vendor compiler reports

    as errors certain assignments that GCC considers to be warnings.

   GDB can produce warnings about symbols that it does not understand.

By default, these warnings are disabled.  You can enable them by

executing `set complaint 10' (which you can put in your ~/.gdbinit if

you like).  I recommend doing this if you are working on a compiler,

assembler, linker, or GDB, since it will point out problems that you

may be able to fix.  Warnings produced during symbol reading indicate

some mismatch between the object file and GDB's symbol reading code.

In many cases, it's a mismatch between the specs for the object file

format, and what the compiler actually outputs or the debugger

actually understands.

Graphical interface to GDB -- X Windows, MS Windows

==========================

   Several graphical interfaces to GDB are available.  You should

check:

        http://sourceware.cygnus.com/gdb/#gui

for an up-to-date list.

   Emacs users will very likely enjoy the Grand Unified Debugger mode;

try typing `M-x gdb RET'.

Writing Code for GDB

=====================

   There is a lot of information about writing code for GDB in the

internals manual, distributed with GDB in gdb/doc/gdbint.texinfo.  You

can read it by hand, print it by using TeX and texinfo, or process it

into an `info' file for use with Emacs' info mode or the standalone

`info' program.

   If you are pondering writing anything but a short patch, especially

take note of the information about copyrights in the node Submitting

Patches.  It can take quite a while to get all the paperwork done, so

we encourage you to start that process as soon as you decide you are

planning to work on something, or at least well ahead of when you

think you will be ready to submit the patches.

GDB Testsuite

=============

   Included with the GDB distribution is a DejaGNU based testsuite

that can either be used to test your newly built GDB, or for

regression testing a GDB with local modifications.

   Running the testsuite requires the prior installation of DejaGNU,

which is generally available via ftp.  The directory

ftp://sourceware.cygnus.com/pub/dejagnu/ will contain a recent

snapshot.  Once DejaGNU is installed, you can run the tests in one of

the following ways:

  (1)   cd gdb-5.0

        make check-gdb

or

  (2)   cd gdb-5.0/gdb

        make check

or

  (3)   cd gdb-5.0/gdb/testsuite

        make site.exp   (builds the site specific file)

        runtest -tool gdb GDB=../gdb    (or GDB= as appropriate)

The last method gives you slightly more control in case of problems

with building one or more test executables or if you are using the

testsuite `standalone', without it being part of the GDB source tree.

See the DejaGNU documentation for further details.

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