566 lines
23 KiB
Plaintext
566 lines
23 KiB
Plaintext
README for gdb-4.7 release
|
||
Stu Grossman & John Gilmore 23 October 1992
|
||
|
||
This is GDB, the GNU source-level debugger, presently running under un*x.
|
||
A summary of new features is in the file `NEWS'.
|
||
|
||
|
||
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-4.7 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-4.7.tar.Z file, you'll get a directory called
|
||
`gdb-4.7', which contains:
|
||
|
||
COPYING.LIB config/ configure.texi mmalloc/
|
||
Makefile.in config.sub* gdb/ move-if-change*
|
||
README configure* glob/ opcodes/
|
||
bfd/ configure.in include/ readline/
|
||
cfg-paper.texi configure.man libiberty/ texinfo/
|
||
|
||
To build GDB, you can just do:
|
||
|
||
cd gdb-4.7
|
||
./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 release includes an already-formatted reference card, ready
|
||
for printing with PostScript or GhostScript, in the `gdb' subdirectory
|
||
of the main source directory--in `gdb-4.7/gdb/refcard.ps' of the
|
||
version 4.7 release. If you can use PostScript or GhostScript with your
|
||
printer, you can print the reference card immediately with `refcard.ps'.
|
||
|
||
The release also includes the source for the reference card. You
|
||
can format it, using TeX, by typing:
|
||
|
||
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.
|
||
|
||
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' subdirectory. The main Info file is
|
||
`gdb-VERSION-NUMBER/gdb/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-4.7', in the case of version 4.7), you can make
|
||
the Info file by typing:
|
||
|
||
cd gdb
|
||
make gdb.info
|
||
|
||
If you want to typeset and print copies of this manual, you need
|
||
TeX, a printing program such as `lpr', and `texinfo.tex', the Texinfo
|
||
definitions file.
|
||
|
||
TeX is 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 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-VERSION-NUMBER/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-4.7/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
|
||
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 4.7 distribution is in the `gdb-4.7'
|
||
directory. That directory contains:
|
||
|
||
`gdb-4.7/configure (and supporting files)'
|
||
script for configuring GDB and all its supporting libraries.
|
||
|
||
`gdb-4.7/gdb'
|
||
the source specific to GDB itself
|
||
|
||
`gdb-4.7/bfd'
|
||
source for the Binary File Descriptor library
|
||
|
||
`gdb-4.7/include'
|
||
GNU include files
|
||
|
||
`gdb-4.7/libiberty'
|
||
source for the `-liberty' free software library
|
||
|
||
`gdb-4.7/opcodes'
|
||
source for the library of opcode tables and disassemblers
|
||
|
||
`gdb-4.7/readline'
|
||
source for the GNU command-line interface
|
||
|
||
`gdb-4.7/glob'
|
||
source for the GNU filename pattern-matching subroutine
|
||
|
||
`gdb-4.7/mmalloc'
|
||
source for the GNU memory-mapped malloc package
|
||
|
||
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-4.7' directory.
|
||
|
||
First switch to the `gdb-VERSION-NUMBER' source directory if you are
|
||
not already in it; then run `configure'. Pass the identifier for the
|
||
platform on which GDB will run as an argument.
|
||
|
||
For example:
|
||
|
||
cd gdb-4.7
|
||
./configure HOST
|
||
make
|
||
|
||
where HOST is an identifier such as `sun4' or `decstation', that
|
||
identifies the platform where GDB will run.
|
||
|
||
Running `configure HOST' 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 HOST
|
||
|
||
If you run `configure' from a directory that contains source
|
||
directories for multiple libraries or programs, such as the `gdb-4.7'
|
||
source directory for version 4.7, `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 4.7, type the following to configure only
|
||
the `bfd' subdirectory:
|
||
|
||
cd gdb-4.7/bfd
|
||
../configure HOST
|
||
|
||
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'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, rather than in
|
||
the source directory. 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.
|
||
|
||
To build `gdb' in a separate directory, run `configure' with the
|
||
`--srcdir' option to specify where to find the source. (You'll 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 4.7, you can build GDB in a separate
|
||
directory for a Sun 4 like this:
|
||
|
||
cd gdb-4.7
|
||
mkdir ../gdb-sun4
|
||
cd ../gdb-sun4
|
||
../gdb-4.7/configure sun4
|
||
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' generated by `configure' for each source directory
|
||
also runs recursively. If you type `make' in a source directory such
|
||
as `gdb-4.7' (or in a separate configured directory configured with
|
||
`--srcdir=PATH/gdb-4.7'), you will build all the required libraries,
|
||
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, but 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-sunos411
|
||
% sh config.sub sun3
|
||
m68k-sun-sunos411
|
||
% sh config.sub decstation
|
||
mips-dec-ultrix42
|
||
% sh config.sub hp300bsd
|
||
m68k-hp-bsd
|
||
% sh config.sub i386v
|
||
i386-unknown-sysv
|
||
% sh config.sub i786v
|
||
Invalid configuration `i786v': machine `i786v' not recognized
|
||
|
||
`config.sub' is also distributed in the GDB source directory
|
||
(`gdb-4.7', for version 4.7).
|
||
|
||
|
||
`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]
|
||
[--target=TARGET] 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 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.
|
||
|
||
`--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 ...'
|
||
Configure GDB to run on the specified HOST.
|
||
|
||
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
|
||
=======================
|
||
|
||
GDB provides some support for debugging C++ progams. 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 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 a 68k, 386, or SPARC 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-hms.c Hitachi Micro Systems H8/300 monitor
|
||
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-4.7), 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-4.7/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' below.
|
||
|
||
|
||
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
|
||
=====================
|
||
|
||
Documentation about GDB's internals is in the subdirectory doc, as
|
||
`gdbint.texinfo'. In particular, there is a `cookbook' there on how
|
||
to port GDB to a new machine. 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.
|
||
|
||
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!
|
||
|
||
There is a list of all known `feature-test macros' in gdbint.texinfo.
|
||
Each such macro should be defined (or left undefined) in a host-dependent,
|
||
target-dependent, or native-dependent include file. Not all of the
|
||
macros are cleanly separated this way, yet. As you make changes, move
|
||
the code toward cleanliness.
|
||
|
||
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:
|