- README for gdb-3.98 beta release
- John Gilmore 31 July 91
+ 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. This is a beta test 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. If your favorite bugfix is not
-yet present here, I encourage you to port it into this version and
-then send the diffs to bug-gdb@prep.ai.mit.edu.
+This is GDB, the GNU source-level debugger, presently running under un*x.
+A summary of new features is in the file `NEWS'.
-A summary of features new since gdb-3.5 is in the file `WHATS.NEW'.
+Unpacking and Installation -- quick overview
+==========================
- Unpacking and Installation
+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.
-This release moves the generic GNU include files, the BFD ("binary file
-description") library, the getopt routines, obstacks, and the readline
-library into the parent directory of gdb. The idea is that a variety
-of GNU tools can share a common copy of these things.
+When you unpack the gdb-4.7.tar.Z file, you'll get a directory called
+`gdb-4.7', which contains:
-These generic files are packaged separately from GDB, in a tar file
-called "bfd.ilrt-3.98.tar.Z". ("ilrt" stands for include, libiberty,
-readline, texinfo). Unpack that tar file in the same directory in
-which you unpacked the gdb-3.98.tar.Z file, so that for example the
-'bfd' directory sits next to the 'gdb' directory. The whole top-level
-directory will look like this with `ls -F':
+ 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/
- Makefile.in configure* include/ texinfo/
- README.configure configure.in libiberty/
- bfd/ gdb/ readline/
+To build GDB, you can just do:
-Once you have this stuff unpacked, and your current directory is here,
-you can type:
-
- ./configure HOSTNAME
+ cd gdb-4.7
+ ./configure HOSTTYPE (e.g. sun4, decstation)
make
+ cp gdb/gdb /usr/local/bin/gdb (or wherever you want)
-and all the libraries, as well as GDB will be configured and built.
+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 `./configure host -target=target';
-see below.
+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.
- More Documentation
+ 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.
-The GDB manual is much expanded and improved. For online browsing,
-gdb/gdb.info is the main file, and there are gdb/gdb.info-1 through -6
-files that can be installed into your main `info' tree. If you want a
-printed version of the manual, you can run, from the GDB source
-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
+ make gdb.dvi
-to make the TeX device-independent output file. This assumes you have
-a running TeX on your system. The source for the GDB manual is in
-doc/gdb.texinfo (and a few other files it includes), provided with
-this distribution. The Makefile attempts to use the texinfo.tex
-supplied as part of the BFD-and-libraries tar file, since the manual
-uses Texinfo-2 which is not in common use yet.
+Installing GDB
+***************
- Configuration Details (extracted from gdb.texinfo)
+ GDB comes with a `configure' script that automates the process of
+preparing GDB for installation; you can then use `make' to build the
+program.
- GDB is distributed 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'.
- The `configure' script that's specific to GDB is distributed in
-the main GDB source directory. However, building GDB also requires
-several other directories of source common to multiple GNU programs.
-These directories (GNU libraries and includes) are distributed
-separately, but their `configure' scripts and `Makefile's are
-designed to work together. To ensure that GDB's `Makefile' can find
-all the pieces, you should make a single overall directory to hold
-the directories of source for GNU libraries and includes, and you
-should install the GDB source directory there too. In this
-Appendix, we refer to the directory of GNU source directories as GNUSRC.
+ For example, the GDB version 4.7 distribution is in the `gdb-4.7'
+directory. That directory contains:
- At a minimum, to build GDB you need the directories
+`gdb-4.7/configure (and supporting files)'
+ script for configuring GDB and all its supporting libraries.
-`GNUSRC/gdb'
+`gdb-4.7/gdb'
the source specific to GDB itself
-`GNUSRC/bfd'
- source for the Binary File Descriptor Library
+`gdb-4.7/bfd'
+ source for the Binary File Descriptor library
-`GNUSRC/include'
+`gdb-4.7/include'
GNU include files
-`GNUSRC/libiberty'
+`gdb-4.7/libiberty'
source for the `-liberty' free software library
-`GNUSRC/readline'
+`gdb-4.7/opcodes'
+ source for the library of opcode tables and disassemblers
+
+`gdb-4.7/readline'
source for the GNU command-line interface
-Each of these directories has its own `configure' script. GNUSRC has
-an overall `configure' script, which is distributed with the GNU
-libraries and includes.
+`gdb-4.7/glob'
+ source for the GNU filename pattern-matching subroutine
- `configure' is designed to be called recursively, so it is most
-convenient to run `configure' from the GNUSRC directory. The
-simplest way to configure and build GDB is the following:
+`gdb-4.7/mmalloc'
+ source for the GNU memory-mapped malloc package
- cd GNUSRC
- ./configure HOST
- make
+ 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.
-where HOST is something like `sun4' or `vax', 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.
-
- 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; 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 build GDB for several host or target machines, and if your
-`make' program handles the `VPATH' feature (GNU `make' does), it is
-most convenient instead to build the different GDB configurations in
-subdirectories (separate from the source). `configure' does this
-for you when you simultaneously specify several configurations; but
-it's a good habit even for a single configuration. You can specify
-the use of subdirectories using the `+forcesubdirs' option
-(abbreviated `+f'). For example, you can build GDB on a Sun 4 as
-follows:
-
- cd GNUSRC
- ./configure +f sun4
- cd Host-sun4/Target-sun4
- make
+ 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.
- When `configure' uses subdirectories to build programs or
-libraries, it creates nested directories `Host-HOST/Target-MACHINE'.
-This is 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=MACHINE' option to `configure'. Specifying
-only hosts still gives you two levels of subdirectory for each host,
-with the same machine-name suffix on both. 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.
+ For example:
- 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 `Host-HOST/Target-MACHINE' subdirectories, run `make' in those
-subdirectories.
-
- Each `configure' and `Makefile' under each source directory runs
-recursively, so that typing `make' in GNUSRC (or in a
-`GNUSRC/Host-HOST/Target-MACHINE' subdirectory) builds all the
-required libraries, then GDB.
+ cd gdb-4.7
+ ./configure HOST
+ make
- If you run `configure' from a directory (such as GNUSRC) that
-contains source directories for multiple libraries or programs,
-`configure' creates the `Host-HOST/Target-MACHINE' subdirectories in
-each library or program's source directory. For example, typing:
+where HOST is an identifier such as `sun4' or `decstation', that
+identifies the platform where GDB will run.
- cd GNUSRC
- configure sun4 +target=vx960
+ 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.
-creates the following 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:
- GNUSRC/Host-sun4/Target-vx960
- GNUSRC/bfd/Host-sun4/Target-vx960
- GNUSRC/gdb/Host-sun4/Target-vx960
- GNUSRC/libiberty/Host-sun4/Target-vx960
- GNUSRC/readline/Host-sun4/Target-vx960
+ sh configure HOST
-The `Makefile' in `GNUSRC/Host-sun4/Target-vx960' will `cd' to the
-appropriate lower-level directories (such as
-`GNUSRC/bfd/Host-sun4/Target-vx960'), building each in turn.
+ 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).
- 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 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:
- `configure' Options
+ cd gdb-4.7/bfd
+ ../configure HOST
- Here is a summary of all the `configure' options and arguments
-that you might use for building GDB:
+ 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.
- configure [+destdir=DIR] [+forcesubdirs] [+norecur] [+rm]
- [+target=MACHINE...] HOST...
-You may introduce options with the character `-' rather than `+' if
-you prefer; but options introduced with `+' may be truncated.
+Compiling GDB in Another Directory
+===================================
-`+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'.
+ 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.
-`+forcesubdirs'
- Write configuration specific files in subdirectories of the form
+ 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.)
- Host-MACHINE/Target-MACHINE
+ For example, with version 4.7, you can build GDB in a separate
+directory for a Sun 4 like this:
- (and configure the `Makefile' to write binaries there too).
- 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=MACHINE' option on the `configure' command line.
+ cd gdb-4.7
+ mkdir ../gdb-sun4
+ cd ../gdb-sun4
+ ../gdb-4.7/configure sun4
+ make
-`+norecur'
- Configure only the directory where `configure' is executed; do
- not propagate configuration to subdirectories.
+ 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'.
-`+rm'
- Remove the configuration specified by other arguments.
+ 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'.
-`+target=MACHINE ...'
- Configure GDB for cross-debugging programs running on each
- specified MACHINE. You may specify as many `+target' options
- as you wish. To see a list of available targets, execute `ls
- tconfig' in the GDB source directory. Without this option, GDB
- is configured to debug programs that run on the same machine
- (HOST) as GDB itself.
+ 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 each specified HOST. You may specify as
- many host names as you wish. To see a list of available hosts,
- execute `ls xconfig' in the GDB source directory.
+ 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.
+other GNU tools recursively; but these are the only options that affect
+GDB or its supporting libraries.
+
- Languages other than C
+Languages other than C
+=======================
-C++ support has been integrated into 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).
-There is an effort to produce a GDB that works with Modula-2. 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.
+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
+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.
+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
+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 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.
-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).
+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.
-[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 rem-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.
-
- Reporting Bugs
+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.
-
-"mcheck.c", line 32, will produce a pointer conversion warning, which
-can be ignored.
-
-When gdb reads object files produced by the Sun bundled C compiler,
-you will often get a "bad block start address patched" message. You
-can shut off such messages with the command `set complaint 0' (which
-you can put in your ~/.gdbinit if you like). Messages like this
-during symbol reading indicate some mismatch between the object file
-and GDB's symbol reading code (in this case, it's a mismatch
-between the specs for the object file format, and what Sun's compiler
-actually outputs).
-
-If you port gdb to a new machine, please send the required changes
-to bug-gdb@prep.ai.mit.edu. 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
+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.
(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 configure).
-This file contains macro definitions about the target machine's
-registers, stack frame format and instructions.
-
-xm-XXX.h (xm.h is a link to this file, created by configure).
-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.
+Writing Code for GDB
+=====================
-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.
-
-
- 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
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
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,
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
and exec_file_command.
- Debugging gdb with itself
+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
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 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.
+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 compiled gdb with your local cc or taken
-appropriate precautions regarding ansification of include files. See
-the Makefile for more information.
+Also, make sure that you've either compiled gdb with your local cc, or
+have run `fixincludes' if you are compiling with gcc.
\f
(this is for editing this file with GNU emacs)
Local Variables:
projects / deliverable / binutils-gdb.git / blobdiff