565 lines
23 KiB
Text
565 lines
23 KiB
Text
README for gdb-4.3 release
|
||
John Gilmore 7 Dec 1991
|
||
|
||
This is GDB, the GNU source-level debugger, presently running under un*x.
|
||
A summary of features new since gdb-3.5 is in the file `WHATS.NEW'.
|
||
|
||
|
||
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 a miscellaneous library all have directories of their own underneath
|
||
the gdb-4.3 directory. The idea is that a variety of GNU tools can
|
||
share a common copy of these things. 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-4.3.tar.Z file, you'll get a directory called
|
||
`gdb-4.3', which contains:
|
||
|
||
Makefile.in config/ gdb/ texinfo/
|
||
README config.sub* include/
|
||
README.configure configure* libiberty/
|
||
bfd/ configure.in readline/
|
||
|
||
To build GDB, you can just do:
|
||
|
||
cd gdb-4.3
|
||
./configure HOSTTYPE (e.g. sun4, decstation)
|
||
make
|
||
cp gdb/gdb /usr/local/bin/gdb (or wherever you want)
|
||
|
||
This will configure and build all the libraries as well as GDB.
|
||
If you get compiler warnings during this stage, see the `Reporting Bugs'
|
||
section below; there are a few known problems.
|
||
|
||
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
|
||
==================
|
||
|
||
The GDB 4.3 release includes an already-formatted reference card,
|
||
ready for printing on a PostScript printer, as
|
||
`gdb-4.3/gdb/refcard.ps'. It uses the most common PostScript fonts:
|
||
the Times family, Courier, and Symbol. If you have a PostScript
|
||
printer, you can print the reference card by just sending `refcard.ps'
|
||
to the printer.
|
||
|
||
The release also includes the online Info version of this manual
|
||
already formatted: the main Info file is `gdb-4.3/gdb/gdb.info', and it
|
||
refers to subordinate files matching `gdb.info*' in the same directory.
|
||
|
||
If you want to make these Info files yourself from the GDB manual's
|
||
source, you need the GNU `makeinfo' program. Once you have it, you
|
||
can type
|
||
|
||
cd gdb-4.3/gdb
|
||
make gdb.info
|
||
|
||
to make the Info file.
|
||
|
||
If you want to format and print copies of the manual, you need
|
||
several things:
|
||
|
||
* TeX, the public domain typesetting program written by Donald
|
||
Knuth, must be installed on your system and available through
|
||
your execution path.
|
||
|
||
* `gdb-4.3/texinfo': TeX macros defining the GNU Documentation
|
||
Format.
|
||
|
||
* *A DVI output program.* TeX does not actually make marks on
|
||
paper; it produces output files called DVI files. If your system
|
||
has TeX installed, chances are it has a program for printing out
|
||
these files; one popular example is `dvips', which can print DVI
|
||
files on PostScript printers.
|
||
|
||
Once you have these things, you can type
|
||
|
||
cd gdb-4.3/gdb
|
||
make gdb.dvi
|
||
|
||
to format the text of this manual, and print it with the usual output
|
||
method for TeX DVI files at your site.
|
||
|
||
If you want to print the reference card, but do not have a
|
||
PostScript printer, or you want to use Computer Modern fonts instead,
|
||
you can still print it if you have TeX. Format the reference card by
|
||
typing
|
||
|
||
cd gdb-4.3/gdb
|
||
make refcard.dvi
|
||
|
||
The GDB reference card is designed to print in landscape mode on US
|
||
"letter" size paper; that is, on a sheet 11 inches wide by 8.5 inches
|
||
high. You will need to specify this form of printing as an option to
|
||
your DVI output program.
|
||
|
||
|
||
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 `gdb-4.3'. That directory in turn contains:
|
||
|
||
`gdb-4.3/configure (and supporting files)'
|
||
script for configuring GDB and all its supporting libraries.
|
||
|
||
`gdb-4.3/gdb'
|
||
the source specific to GDB itself
|
||
|
||
`gdb-4.3/bfd'
|
||
source for the Binary File Descriptor Library
|
||
|
||
`gdb-4.3/include'
|
||
GNU include files
|
||
|
||
`gdb-4.3/libiberty'
|
||
source for the `-liberty' free software library
|
||
|
||
`gdb-4.3/readline'
|
||
source for the GNU command-line interface
|
||
|
||
It is most convenient to run `configure' from the `gdb-4.3' directory.
|
||
The simplest way to configure and build GDB is the following:
|
||
|
||
cd gdb-4.3
|
||
./configure HOST
|
||
make
|
||
|
||
where HOST is something like `sun4' or `decstation', that identifies
|
||
the platform where GDB will run. This builds the three libraries
|
||
`bfd', `readline', and `libiberty', 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 HOST'.
|
||
|
||
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,
|
||
to configure only the `bfd' subdirectory,
|
||
|
||
cd gdb-4.3/bfd
|
||
../configure HOST
|
||
|
||
You can install `gdb' anywhere; it has no hardwired paths. Simply
|
||
copy `gdb/gdb' to the desired directory.
|
||
|
||
However, you should make sure that the shell on your path (named by
|
||
the `SHELL' environment variable) is publicly readable; some systems
|
||
refuse to let GDB debug child processes whose programs are not
|
||
readable, and GDB uses the shell to start your program.
|
||
|
||
|
||
Configuration Subdirectories
|
||
============================
|
||
|
||
If you want to run GDB versions for several host or target machines,
|
||
you'll 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. If your
|
||
`make' program handles the `VPATH' feature (GNU `make' does), running
|
||
`make' in each of these directories then builds the gdb program
|
||
specified there.
|
||
|
||
`configure' creates these subdirectories for you when you
|
||
simultaneously specify several configurations; but it is a good habit
|
||
even for a single configuration. You can specify the use of
|
||
subdirectories using the `+subdirs' option (abbreviated `+sub'). For
|
||
example, you can build GDB this way on a Sun 4 as follows:
|
||
|
||
cd gdb-4.3
|
||
./configure +sub sun4
|
||
cd H-sun4/T-sun4
|
||
make
|
||
|
||
When `configure' uses subdirectories to build programs or
|
||
libraries, it creates nested directories `H-HOST/T-TARGET'.
|
||
`configure' uses these two directory levels because GDB can be
|
||
configured for cross-compiling: GDB can run on one machine (the host)
|
||
while debugging programs that run on another machine (the target).
|
||
You specify cross-debugging targets by giving the `+target=TARGET'
|
||
option to `configure'. Specifying only hosts still gives you two
|
||
levels of subdirectory for each host, with the same configuration
|
||
suffix on both; that is, if you give any number of hosts but no
|
||
targets, GDB will be configured for native debugging on each host. On
|
||
the other hand, whenever you specify both hosts and targets on the
|
||
same command line, `configure' creates all combinations of the hosts
|
||
and targets you list.
|
||
|
||
If you run `configure' from a directory (notably, `gdb-4.3') that
|
||
contains source directories for multiple libraries or programs,
|
||
`configure' creates the `H-HOST/T-TARGET' subdirectories in each
|
||
library or program's source directory. For example, typing:
|
||
|
||
cd gdb-4.3
|
||
configure sun4 +target=vxworks960
|
||
|
||
creates the following directories:
|
||
|
||
gdb-4.3/H-sun4/T-vxworks960
|
||
gdb-4.3/bfd/H-sun4/T-vxworks960
|
||
gdb-4.3/gdb/H-sun4/T-vxworks960
|
||
gdb-4.3/libiberty/H-sun4/T-vxworks960
|
||
gdb-4.3/readline/H-sun4/T-vxworks960
|
||
|
||
When you run `make' to build a program or library, you must run it
|
||
in a configured directory. If you made a single configuration,
|
||
without subdirectories, run `make' in the source directory. If you
|
||
have `H-HOST/T-TARGET' subdirectories, run `make' in those
|
||
subdirectories.
|
||
|
||
The `Makefile' generated by `configure' for each source directory
|
||
runs recursively, so that typing `make' in `gdb-4.3' (or in a
|
||
`gdb-4.3/H-HOST/T-TARGET' subdirectory) builds all the required
|
||
libraries, then GDB.
|
||
|
||
When you have multiple hosts or targets configured, 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.
|
||
|
||
You can also use the `+objdir=ALTROOT' option to have the
|
||
configured files placed in a parallel directory structure rather than
|
||
alongside the source files; *note configure Options::..
|
||
|
||
|
||
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, but the equivalent full name is
|
||
`sparc-sun-sunos4'.
|
||
|
||
The following table shows all the architectures, hosts, and OS
|
||
prefixes that `configure' recognizes in GDB 4.3. Entries in the "OS
|
||
prefix" column ending in a `*' may be followed by a release number.
|
||
|
||
|
||
ARCHITECTURE VENDOR OS prefix
|
||
------------+--------------------------+---------------------------
|
||
| |
|
||
580 | altos hp | aix* msdos*
|
||
a29k | amd ibm | amigados newsos*
|
||
alliant | amdahl intel | aout nindy*
|
||
arm | aout isi | bout osf*
|
||
c1 | apollo little | bsd* sco*
|
||
c2 | att mips | coff sunos*
|
||
cray2 | bcs motorola | ctix* svr4
|
||
h8300 | bout ncr | dgux* sym*
|
||
i386 | bull next | dynix* sysv*
|
||
i860 | cbm nyu | ebmon ultrix*
|
||
i960 | coff sco | esix* unicos*
|
||
m68000 | convergent sequent | hds unos*
|
||
m68k | convex sgi | hpux* uts
|
||
m88k | cray sony | irix* v88r*
|
||
mips | dec sun | isc* vms*
|
||
ns32k | encore unicom | kern vxworks*
|
||
pyramid | gould utek | mach*
|
||
romp | hitachi wrs |
|
||
rs6000 | |
|
||
sparc | |
|
||
tahoe | |
|
||
tron | |
|
||
vax | |
|
||
xmp | |
|
||
ymp | |
|
||
|
||
*Warning:* `configure' can represent a very large number of
|
||
combinations of architecture, vendor, and OS. There is by no
|
||
means support available for all possible combinations!
|
||
|
||
The `configure' script accompanying GDB 4.3 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
|
||
% sh config.sub sun3
|
||
m68k-sun-sunos4
|
||
% sh config.sub decstation
|
||
mips-dec-ultrix
|
||
% sh config.sub hp300bsd
|
||
m68k-hp-bsd
|
||
% sh config.sub i386v
|
||
i386-none-sysv
|
||
% sh config.sub i486v
|
||
*** Configuration "i486v" not recognized
|
||
|
||
`config.sub' is also distributed in the directory `gdb-4.3'.
|
||
|
||
|
||
`configure' Options
|
||
===================
|
||
|
||
Here is a summary of all the `configure' options and arguments that
|
||
you might use for building GDB:
|
||
|
||
configure [+destdir=DIR] [+subdirs]
|
||
[+objdir=ALTROOT] [+norecursion] [+rm]
|
||
[+target=TARGET...] HOST...
|
||
|
||
You may introduce options with the character `-' rather than `+' if
|
||
you prefer; but you may abbreviate option names if you use `+'.
|
||
|
||
`+destdir=DIR'
|
||
DIR is an installation directory *path prefix*. After you
|
||
configure with this option, `make install' will install GDB as
|
||
`DIR/bin/gdb', and the libraries in `DIR/lib'. If you specify
|
||
`+destdir=/usr/local', for example, `make install' creates
|
||
`/usr/local/bin/gdb'.
|
||
|
||
`+subdirs'
|
||
Write configuration specific files in subdirectories of the form
|
||
|
||
H-HOST/T-TARGET
|
||
|
||
(and configure the `Makefile' to generate object code in
|
||
subdirectories of this form as well). Without this option, if you
|
||
specify only one configuration for GDB, `configure' will use the
|
||
same directory for source, configured files, and binaries. This
|
||
option is used automatically if you specify more than one HOST or
|
||
more than one `+target=TARGET' option on the `configure' command
|
||
line.
|
||
|
||
`+norecursion'
|
||
Configure only the directory where `configure' is executed; do not
|
||
propagate configuration to subdirectories.
|
||
|
||
`+objdir=ALTROOT'
|
||
ALTROOT is an alternative directory used as the root for
|
||
configured files. `configure' will create directories under
|
||
ALTROOT in parallel to the source directories. If you use
|
||
`+objdir=ALTROOT' with `+subdirs', `configure' also builds the
|
||
`H-HOST/T-TARGET' subdirectories in the directory tree rooted in
|
||
ALTROOT.
|
||
|
||
`+rm'
|
||
Remove the configuration that the other arguments specify.
|
||
|
||
`+target=TARGET ...'
|
||
Configure GDB for cross-debugging programs running on each
|
||
specified TARGET. You may specify as many `+target' options as
|
||
you wish. 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 ...'
|
||
Configure GDB to run on each specified HOST. You may specify as
|
||
many host names as you wish.
|
||
|
||
There is no convenient way to generate a list of all available
|
||
hosts.
|
||
|
||
`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
|
||
|
||
C++ support has been integrated into gdb. Partial Modula-2 support is
|
||
now in GDB. GDB should work with FORTRAN programs. (If you have
|
||
problems, please send a bug report; you may have to refer to some
|
||
FORTRAN variables with a trailing underscore). I am not aware of
|
||
anyone who is working on getting gdb to use the syntax of any other
|
||
language. Pascal programs which use sets, subranges, file variables,
|
||
or nested functions will not currently work.
|
||
|
||
|
||
Kernel debugging
|
||
|
||
I have't done this myself so I can't really offer any advice.
|
||
Remote debugging over serial lines works fine, but the kernel debugging
|
||
code in here has not been tested in years. Van Jacobson claims to have
|
||
better kernel debugging, but won't release it for ordinary mortals.
|
||
|
||
|
||
Remote debugging
|
||
|
||
The files m68k-stub.c and i386-stub.c contain two examples of remote
|
||
stubs to be used with remote.c. They are designeded to run standalone
|
||
on a 68k or 386 cpu and communicate properly with the remote.c stub
|
||
over a serial line.
|
||
|
||
The file rem-multi.shar contains a general stub that can probably
|
||
run on various different flavors of unix to allow debugging over a
|
||
serial line from one machine to another.
|
||
|
||
Some working remote interfaces for talking to existing ROM monitors
|
||
are:
|
||
remote-eb.c AMD 29000 "EBMON"
|
||
remote-nindy.c Intel 960 "Nindy"
|
||
remote-adapt.c AMD 29000 "Adapt"
|
||
remote-mm.c AMD 29000 "minimon"
|
||
|
||
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.
|
||
|
||
|
||
Reporting Bugs
|
||
|
||
The correct address for reporting bugs found in gdb is
|
||
"bug-gdb@prep.ai.mit.edu". Please email all bugs to that address.
|
||
Please include the GDB version number (e.g. gdb-4.3), and how
|
||
you configured it (e.g. "sun4" or "mach386 host, i586-intel-synopsys
|
||
target").
|
||
|
||
A known bug:
|
||
|
||
* If you run with a watchpoint enabled, breakpoints will become
|
||
erratic and might not stop the program. Disabling or deleting the
|
||
watchpoint will fix the problem.
|
||
|
||
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.
|
||
|
||
If you port gdb to a new machine, please send the required changes to
|
||
bug-gdb@prep.ai.mit.edu. There's lots of information about doing your
|
||
own port in the file gdb-4.3/gdb/doc/gdbint.texinfo, which you can
|
||
print out, or read with `info' (see the Makefile.in there). If your
|
||
changes are more than a few lines, obtain and send in a copyright
|
||
assignment from gnu@prep.ai.mit.edu, as described in the section
|
||
`Writing Code for GDB'.
|
||
|
||
|
||
X Windows versus GDB
|
||
|
||
xgdb is obsolete. We are not doing any development or support of it.
|
||
|
||
There is an "xxgdb", which shows more promise, which was posted to
|
||
comp.sources.x.
|
||
|
||
For those intersted in auto display of source and the availability of
|
||
an editor while debugging I suggest trying gdb-mode in gnu-emacs
|
||
(Try typing M-x gdb RETURN). Comments on this mode are welcome.
|
||
|
||
|
||
Writing Code for GDB
|
||
|
||
We appreciate having users contribute code that is of general use, but
|
||
for it to be included in future GDB releases it must be cleanly
|
||
written. We do not want to include changes that will needlessly make
|
||
future maintainance difficult. It is not much harder to do things
|
||
right, and in the long term it is worth it to the GNU project, and
|
||
probably to you individually as well.
|
||
|
||
If you make substantial changes, you'll have to file a copyright
|
||
assignment with the Free Software Foundation before we can produce a
|
||
release that includes your changes. Send mail requesting the copyright
|
||
assignment to gnu@prep.ai.mit.edu. Do this early, like before the
|
||
changes actually work, or even before you start them, because a manager
|
||
or lawyer on your end will probably make this a slow process.
|
||
|
||
Please code according to the GNU coding standards. If you do not have
|
||
a copy, you can request one by sending mail to gnu@prep.ai.mit.edu.
|
||
|
||
Please try to avoid making machine-specific changes to
|
||
machine-independent files. If this is unavoidable, put a hook in the
|
||
machine-independent file which calls a (possibly) machine-dependent
|
||
macro (for example, the IGNORE_SYMBOL macro can be used for any
|
||
symbols which need to be ignored on a specific machine. Calling
|
||
IGNORE_SYMBOL in dbxread.c is a lot cleaner than a maze of #if
|
||
defined's). The machine-independent code should do whatever "most"
|
||
machines want if the macro is not defined in param.h. Using #if
|
||
defined can sometimes be OK (e.g. SET_STACK_LIMIT_HUGE) but should be
|
||
conditionalized on a specific feature of an operating system (set in
|
||
tm.h or xm.h) rather than something like #if defined(vax) or #if
|
||
defined(SYSV). If you use an #ifdef on some symbol that is defined
|
||
in a header file (e.g. #ifdef TIOCSETP), *please* make sure that you
|
||
have #include'd the relevant header file in that module!
|
||
|
||
It is better to replace entire routines which may be system-specific,
|
||
rather than put in a whole bunch of hooks which are probably not going
|
||
to be helpful for any purpose other than your changes. For example,
|
||
if you want to modify dbxread.c to deal with DBX debugging symbols
|
||
which are in COFF files rather than BSD a.out files, do something
|
||
along the lines of a macro GET_NEXT_SYMBOL, which could have
|
||
different definitions for COFF and a.out, rather than trying to put
|
||
the necessary changes throughout all the code in dbxread.c that
|
||
currently assumes BSD format.
|
||
|
||
When generalizing GDB along a particular interface, please use an
|
||
attribute-struct rather than inserting tests or switch statements
|
||
everywhere. For example, GDB has been generalized to handle multiple
|
||
kinds of remote interfaces -- not by #ifdef's everywhere, but by
|
||
defining the "target_ops" structure and having a current target (as
|
||
well as a stack of targets below it, for memory references). Whenever
|
||
something needs to be done that depends on which remote interface we
|
||
are using, a flag in the current target_ops structure is tested (e.g.
|
||
`target_has_stack'), or a function is called through a pointer in the
|
||
current target_ops structure. In this way, when a new remote interface
|
||
is added, only one module needs to be touched -- the one that actually
|
||
implements the new remote interface. Other examples of
|
||
attribute-structs are BFD access to multiple kinds of object file
|
||
formats, or GDB's access to multiple source languages.
|
||
|
||
Please avoid duplicating code. For example, in GDB 3.x all the stuff
|
||
in infptrace.c was duplicated in *-dep.c, and so changing something
|
||
was very painful. In GDB 4.x, these have all been consolidated
|
||
into infptrace.c. infptrace.c can deal with variations between
|
||
systems the same way any system-independent file would (hooks, #if
|
||
defined, etc.), and machines which are radically different don't need
|
||
to use infptrace.c at all. The same was true of core_file_command
|
||
and exec_file_command.
|
||
|
||
|
||
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 4.0, a program can't be running in one process while it is being
|
||
debugged in another. Rather than doing "./gdb ./gdb", which works on
|
||
Suns and such, you can copy gdb to gdb2 and then do "./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.
|
||
|
||
I strongly recommend printing out the reference card and using it.
|
||
Send reference-card suggestions to bug-gdb@prep.ai.mit.edu, just like bugs.
|
||
|
||
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 a
|
||
M-period.
|
||
|
||
Also, make sure that you've either compiled gdb with your local cc, or
|
||
have run `fixincludes' if you are compiling with gcc.
|
||
|
||
(this is for editing this file with GNU emacs)
|
||
Local Variables:
|
||
mode: text
|
||
End:
|