-This is GDB, the GNU source-level debugger, presently running under
-un*x. This is a pre-alpha version of GDB version 4, and has NOT been
-extensively tested. It surely has some bugs, both bugs that were
-present in version 3 and new bugs. I have filed all the bug reports
-and fixes mailed to bug-gdb, and the fixes in particular will move
-into these sources as I find the time.
-
- => THIS VERSION IS PARTICULARLY FRAGILE! <=
-
- It depends on a preliminary version of a new "binary file
- descriptor" library and a new global "include" directory, which
- are packaged separately from GDB. You must obtain, configure
- and build this library manually, then configure and build gdb.
- When building gdb's for multiple platforms, you must manually
- rebuild the bfd library separately for each platform. Yes, of
- course, we are working on this! FIXME!
-
- Configure bfd for your host system by:
-
- cd ../bfd
- edit Makefile
- make
-
- Then you can cd ../gdb-whatever, and config and build gdb.
-
-This release moves the generic GNU include files, the BFD library,
-and the getopt routines into the parent directory of gdb. The idea
-is that a variety of GNU tools can share a common copy of these things.
-
-A summary of features new since gdb-3.5 is in the file `WHATS.NEW'.
-
-The best way to build GDB, in my opinion, is in a subdirectory. I use
-a naming convention "=XXX" where XXX is the machine type I'm building
-for. Nothing depends on this, it's just how I remember which
-subdirectories are what. So, once you have the BFD library built for
-that machine, you can do:
-
- cd gdb-x.yy (the directory where this README is)
- mkdir =XXX (e.g. mkdir =vax)
- cd =XXX
- ../config.gdb machine
- make
+ README for gdb-4.4 release
+ John Gilmore & Stu Grossman 31 Jan 1992
+
+This is GDB, the GNU source-level debugger, presently running under un*x.
+A summary of new features is in the file `WHATS.NEW'.
+
+
+Unpacking and Installation -- quick overview
+==========================
-Machine is like "vax" or "sun4". For more information type `../config.gdb'.
+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-4.4 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.
-Once you have done that, just `make' will do everything, producing an
-executable `gdb' in this directory.
+When you unpack the gdb-4.4.tar.Z file, you'll get a directory called
+`gdb-4.4', which contains:
+
+ DOC.configure bfd/ configure* glob/ readline/
+ Makefile.in config/ configure.in include/ texinfo/
+ README config.sub* gdb/ libiberty/
+
+To build GDB, you can just do:
+
+ cd gdb-4.4
+ ./configure HOSTTYPE (e.g. sun4, decstation)
+ make
+ cp gdb/gdb /usr/local/bin/gdb (or wherever you want)
-You can also build gdb binaries in a completely different directory from its
-sources, by specifying "srcdir=YYY" to config.gdb, giving it an absolute
-or relative path to the source directory.
+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. You
-configure it this way by specifying `config.gdb host target' where host
-is where GDB runs, and target is where your program runs.
+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 on a PostScript or GhostScript printer, in the `gdb'
+subdirectory of the main source directory--in `gdb-4.4/gdb/refcard.ps'
+of the version 4.4 release. If you have a PostScript or GhostScript
+printer, you can print the reference card by just sending `refcard.ps'
+to the printer.
+
+ If all you have is TeX, format the GDB reference card 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 online
+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 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-4.4', in the case of version 4.4), 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-4.4/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 4.4 distribution is in the `gdb-4.4'
+directory. That directory contains:
+
+`gdb-4.4/configure (and supporting files)'
+ script for configuring GDB and all its supporting libraries.
+
+`gdb-4.4/gdb'
+ the source specific to GDB itself
-If you want a new (current to this release) version of the manual, you
-will have to use the gdb.texinfo file provided with this distribution.
-For details see the texinfo manual (distributed with emacs and as a
-printed manual).
+`gdb-4.4/bfd'
+ source for the Binary File Descriptor Library
-About languages other than C...
+`gdb-4.4/include'
+ GNU include files
-C++ support has been integrated into gdb. GDB should work with FORTRAN
-programs (if you have problem, please send a bug report; note that you
-may have to refer to some FORTRAN variables with a trailing
-underscore), but I am not aware of anyone who is working on getting it
-to use the syntax of any language other than C or C++. Pascal programs
-which use sets, subranges, file variables, or nested functions will not
-currently work.
+`gdb-4.4/libiberty'
+ source for the `-liberty' free software library
+
+`gdb-4.4/readline'
+ source for the GNU command-line interface
+
+ 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-4.4' 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.
-About kernel debugging...
+ For example:
+
+ cd gdb-4.4
+ ./configure HOST
+ make
+
+where HOST is an identifier such as `sun4' or `decstation', that
+identifies the platform where GDB will run.
+
+ These `configure' and `make' commands build 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
+
+ If you run `configure' from a directory that contains source
+directories for multiple libraries or programs, such as the `gdb-4.4'
+source directory for version 4.4, `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 4.4, type the following to configure only
+the `bfd' subdirectory:
+
+ cd gdb-4.4/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. (Remember,
+you'll also need to specify a path to find `configure' itself from
+your working directory.)
+
+ For example, with version 4.4, you can build GDB in a separate
+directory for a Sun 4 like this:
+
+ cd gdb-4.4
+ mkdir ../gdb-sun4
+ cd ../gdb-sun4
+ ../gdb-4.4/configure --srcdir=../gdb-4.4 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 use for building 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-4.4' (or in a separate configured directory configured with
+`--srcdir=PATH/gdb-4.4'), 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 following table shows all the architectures, hosts, and OS
+prefixes that `configure' recognizes in GDB version 4.4. 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 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 GDB source directory
+(`gdb-4.4', for version 4.4).
+
+
+`configure' Options
+===================
+
+ Here is a summary of all the `configure' options and arguments that
+you might use for building GDB:
+
+ configure [--destdir=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 `--'.
+
+`--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'.
+
+`--srcdir=PATH'
+ 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 is more like to be in a currently
-functioning state than the standalone gdb (kdb). FIXME.
-
-About remote debugging...
-
-[This section seems to be out of date, I have never seen the "rapp"
-program, though I would like to. FIXME.]
-`rapp' runs under unix and acts as a remote stub (like remote-multi.shar
-distributed with GDB version 3). Currently it just works over UDP
-(network), not over a serial line. To get it running
-* Compile GDB on the host machine as usual
-* Compile rapp on the target machine, giving for both host and target
- the type of the target machine
-* Install "gdb" in /etc/services on both machines.
-
-This will get reworked before the initial release of 4.x. FIXME.
-
-The two files remote-multi.shar and remote-sa.m68k.shar contain two
-examples of a remote stub to be used with remote.c. The the -multi
-file is a general stub that can probably be running on various
-different flavors of unix to allow debugging over a serial line from
-one machine to another. The remote-sa.m68k.shar is designed to run
-standalone on a 68k type cpu and communicate properley with the
-remote.c stub over a serial line.
-
-The files remote-eb.c and remote-nindy.c are two examples of remote
-interfaces for talking to existing ROM monitors (for the AMD 29000 and the
-Intel 960 repsectively). There is also a remote interface for the
-VxWorks realtime kernel, which communicates over TCP/IP, in remote-vx.c
-and the vx-share subdirectory.
-
-About reporting bugs...
-
-The correct address for reporting bugs found with gdb is
+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.
+
+
+ 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-4.4), 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.
-About xgdb...
+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.
-Hopefully a new xgdb will be in 4.x.
+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-4.4/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'.
-xgdb.c was provided to us by the user community; it is not an integral
-part of the gdb distribution. The problem of providing visual
-debugging support on top of gdb is peripheral to the GNU project and
-(at least right now) we can't afford to put time into it. So while we
-will be happy to incorporate user fixes to xgdb.c, we do not guarantee
-that it will work and we will not fix bugs reported in it. See
-XGDB-README for one person's opinion about what is wrong with the
-current xgdb. Someone is working on writing a new XGDB, so improving
-(e.g. by fixing it so that it will work, if it doesn't currently) the
-current one is not worth it.
+
+ 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.
-About the machine-dependent files...
-
-tconfig/<machine>
-This contains Makefile stuff for when the target system is <machine>.
-It also specifies the name of the tm-XXX.h file for this machine.
-
-xconfig/<machine>
-This contains Makefile stuff for when the host system is <machine>.
-It also specifies the name of the xm-XXX.h file for this machine.
-
-tm-XXX.h (tm.h is a link to this file, created by config.gdb).
-This file contains macro definitions that express information
-about the target machine's registers, stack frame format and instructions.
-
-xm-XXX.h (xm.h is a link to this file, created by config.gdb).
-This contains macro definitions describing the host system environment,
-such as byte order, host C compiler and library, ptrace support,
-and core file structure.
-
-<machine>-opcode.h
-<machine>-pinsn.c
-These files contain the information necessary to print instructions
-for your cpu type. <machine>-opcode.h includes some large initialized
-data structures, which is strange for a ".h" file, but it's OK since
-it is only included in one place. <machine>-opcode.h is shared
-between the debugger and the assembler (if the GNU assembler has been
-ported to that machine), whereas <machine>-pinsn.c is specific to GDB.
-
-<machine>-tdep.c
-This file contains any miscellaneous code required for this machine
-as a target. On some machines it doesn't exist at all. Its existence
-is specified in the tconfig/XXX file.
-
-<machine>-xdep.c
-This file contains any miscellaneous code required for this machine
-as a host. On some machines it doesn't exist at all. Its existence
-is specified in the xconfig/XXX file.
-
-infptrace.c
-This is the low level interface to inferior processes for systems
-using the Unix ptrace call in a vanilla way. Some systems have their
-own routines in <machine>-xdep.c. Whether or not it is used
-is specified in the xconfig/XXX file.
-
-coredep.c
-Machine and system-dependent aspects of reading core files. Some
-machines use coredep.c; some have the routines in <machine>-xdep.c.
-Whether or not it is used is specified in the xconfig/XXX file.
-Now that BFD is used to read core files, virtually all machines should
-use coredep.c and should just provide fetch_core_registers in
-<machine>-xdep.c.
-
-exec.c
-Machine and system-dependent aspects of reading executable files.
-Some machines use exec.c; some have the routines in <machine>-tdep.c
-Since BFD, virtually all machines should use exec.c.
-
-About writing code for GDB...
+
+ 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
right, and in the long term it is worth it to the GNU project, and
probably to you individually as well.
-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.
-
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
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
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
+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
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. Thus in GDB 4.x these have all been consolidated
+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.
-About debugging gdb with itself...
-You 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 .
+ 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.
-Also, make sure that you've compiled gdb with your local cc or taken
-appropriate precautions regarding ansification of include files. See
-the Makefile for more information.
+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.
-When you run gdb in this 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.
+Also, make sure that you've either compiled gdb with your local cc, or
+have run `fixincludes' if you are compiling with gcc.
\f
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