565 lines
23 KiB
Plaintext
565 lines
23 KiB
Plaintext
README for gdb-4.4 release
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John Gilmore & Stu Grossman 31 Jan 1992
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This is GDB, the GNU source-level debugger, presently running under un*x.
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A summary of new features is in the file `WHATS.NEW'.
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Unpacking and Installation -- quick overview
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==========================
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In this release, the GDB debugger sources, the generic GNU include
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files, the BFD ("binary file description") library, the readline library,
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and a miscellaneous library all have directories of their own underneath
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the gdb-4.4 directory. The idea is that a variety of GNU tools can
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share a common copy of these things. Configuration scripts and
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makefiles exist to cruise up and down this directory tree and
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automatically build all the pieces in the right order.
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When you unpack the gdb-4.4.tar.Z file, you'll get a directory called
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`gdb-4.4', which contains:
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DOC.configure bfd/ configure* glob/ readline/
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Makefile.in config/ configure.in include/ texinfo/
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README config.sub* gdb/ libiberty/
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To build GDB, you can just do:
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cd gdb-4.4
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./configure HOSTTYPE (e.g. sun4, decstation)
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make
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cp gdb/gdb /usr/local/bin/gdb (or wherever you want)
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This will configure and build all the libraries as well as GDB.
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If you get compiler warnings during this stage, see the `Reporting Bugs'
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section below; there are a few known problems.
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GDB can be used as a cross-debugger, running on a machine of one type
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while debugging a program running on a machine of another type. See below.
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More Documentation
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==================
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The GDB 4.4 release includes an already-formatted reference card,
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ready for printing on a PostScript printer, as
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`gdb-4.4/gdb/refcard.ps'. It uses the most common PostScript fonts:
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the Times family, Courier, and Symbol. If you have a PostScript
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printer, you can print the reference card by just sending `refcard.ps'
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to the printer.
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The release also includes the online Info version of this manual
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already formatted: the main Info file is `gdb-4.4/gdb/gdb.info', and it
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refers to subordinate files matching `gdb.info*' in the same directory.
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If you want to make these Info files yourself from the GDB manual's
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source, you need the GNU `makeinfo' program. Once you have it, you
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can type
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cd gdb-4.4/gdb
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make gdb.info
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to make the Info file.
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If you want to format and print copies of the manual, you need
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several things:
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* TeX, the public domain typesetting program written by Donald
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Knuth, must be installed on your system and available through
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your execution path.
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* `gdb-4.4/texinfo': TeX macros defining the GNU Documentation
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Format.
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* *A DVI output program.* TeX does not actually make marks on
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paper; it produces output files called DVI files. If your system
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has TeX installed, chances are it has a program for printing out
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these files; one popular example is `dvips', which can print DVI
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files on PostScript printers.
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Once you have these things, you can type
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cd gdb-4.4/gdb
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make gdb.dvi
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to format the text of this manual, and print it with the usual output
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method for TeX DVI files at your site.
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If you want to print the reference card, but do not have a
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PostScript printer, or you want to use Computer Modern fonts instead,
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you can still print it if you have TeX. Format the reference card by
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typing
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cd gdb-4.4/gdb
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make refcard.dvi
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The GDB reference card is designed to print in landscape mode on US
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"letter" size paper; that is, on a sheet 11 inches wide by 8.5 inches
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high. You will need to specify this form of printing as an option to
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your DVI output program.
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Installing GDB
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==============
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GDB comes with a `configure' script that automates the process of
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preparing GDB for installation; you can then use `make' to build the
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`gdb' program.
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The gdb distribution includes all the source code you need for gdb
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in a single directory `gdb-4.4'. That directory in turn contains:
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`gdb-4.4/configure (and supporting files)'
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script for configuring GDB and all its supporting libraries.
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`gdb-4.4/gdb'
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the source specific to GDB itself
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`gdb-4.4/bfd'
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source for the Binary File Descriptor Library
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`gdb-4.4/include'
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GNU include files
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`gdb-4.4/libiberty'
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source for the `-liberty' free software library
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`gdb-4.4/readline'
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source for the GNU command-line interface
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It is most convenient to run `configure' from the `gdb-4.4' directory.
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The simplest way to configure and build GDB is the following:
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cd gdb-4.4
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./configure HOST
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make
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where HOST is something like `sun4' or `decstation', that identifies
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the platform where GDB will run. This builds the three libraries
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`bfd', `readline', and `libiberty', then `gdb' itself. The configured
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source files, and the binaries, are left in the corresponding source
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directories.
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`configure' is a Bourne-shell (`/bin/sh') script; if your system
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does not recognize this automatically when you run a different shell,
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you may need to run `sh' on it explicitly: `sh configure HOST'.
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You can *run* the `configure' script from any of the subordinate
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directories in the GDB distribution (if you only want to configure
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that subdirectory); but be sure to specify a path to it. For example,
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to configure only the `bfd' subdirectory,
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cd gdb-4.4/bfd
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../configure HOST
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You can install `gdb' anywhere; it has no hardwired paths. Simply
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copy `gdb/gdb' to the desired directory.
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However, you should make sure that the shell on your path (named by
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the `SHELL' environment variable) is publicly readable; some systems
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refuse to let GDB debug child processes whose programs are not
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readable, and GDB uses the shell to start your program.
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Configuration Subdirectories
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============================
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If you want to run GDB versions for several host or target machines,
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you'll need a different gdb compiled for each combination of host and
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target. `configure' is designed to make this easy by allowing you to
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generate each configuration in a separate subdirectory. If your
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`make' program handles the `VPATH' feature (GNU `make' does), running
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`make' in each of these directories then builds the gdb program
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specified there.
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`configure' creates these subdirectories for you when you
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simultaneously specify several configurations; but it is a good habit
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even for a single configuration. You can specify the use of
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subdirectories using the `+subdirs' option (abbreviated `+sub'). For
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example, you can build GDB this way on a Sun 4 as follows:
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cd gdb-4.4
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./configure +sub sun4
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cd H-sun4/T-sun4
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make
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When `configure' uses subdirectories to build programs or
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libraries, it creates nested directories `H-HOST/T-TARGET'.
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`configure' uses these two directory levels because GDB can be
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configured for cross-compiling: GDB can run on one machine (the host)
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while debugging programs that run on another machine (the target).
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You specify cross-debugging targets by giving the `+target=TARGET'
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option to `configure'. Specifying only hosts still gives you two
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levels of subdirectory for each host, with the same configuration
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suffix on both; that is, if you give any number of hosts but no
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targets, GDB will be configured for native debugging on each host. On
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the other hand, whenever you specify both hosts and targets on the
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same command line, `configure' creates all combinations of the hosts
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and targets you list.
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If you run `configure' from a directory (notably, `gdb-4.4') that
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contains source directories for multiple libraries or programs,
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`configure' creates the `H-HOST/T-TARGET' subdirectories in each
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library or program's source directory. For example, typing:
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cd gdb-4.4
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configure sun4 +target=vxworks960
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creates the following directories:
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gdb-4.4/H-sun4/T-vxworks960
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gdb-4.4/bfd/H-sun4/T-vxworks960
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gdb-4.4/gdb/H-sun4/T-vxworks960
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gdb-4.4/libiberty/H-sun4/T-vxworks960
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gdb-4.4/readline/H-sun4/T-vxworks960
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When you run `make' to build a program or library, you must run it
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in a configured directory. If you made a single configuration,
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without subdirectories, run `make' in the source directory. If you
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have `H-HOST/T-TARGET' subdirectories, run `make' in those
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subdirectories.
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The `Makefile' generated by `configure' for each source directory
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runs recursively, so that typing `make' in `gdb-4.4' (or in a
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`gdb-4.4/H-HOST/T-TARGET' subdirectory) builds all the required
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libraries, then GDB.
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When you have multiple hosts or targets configured, you can run
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`make' on them in parallel (for example, if they are NFS-mounted on
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each of the hosts); they will not interfere with each other.
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You can also use the `+objdir=ALTROOT' option to have the
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configured files placed in a parallel directory structure rather than
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alongside the source files; *note configure Options::..
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Specifying Names for Hosts and Targets
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======================================
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The specifications used for hosts and targets in the `configure'
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script are based on a three-part naming scheme, but some short
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predefined aliases are also supported. The full naming scheme encodes
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three pieces of information in the following pattern:
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ARCHITECTURE-VENDOR-OS
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For example, you can use the alias `sun4' as a HOST argument or in
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a `+target=TARGET' option, but the equivalent full name is
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`sparc-sun-sunos4'.
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The following table shows all the architectures, hosts, and OS
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prefixes that `configure' recognizes in GDB 4.4. Entries in the "OS
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prefix" column ending in a `*' may be followed by a release number.
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ARCHITECTURE VENDOR OS prefix
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------------+--------------------------+---------------------------
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580 | altos hp | aix* msdos*
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a29k | amd ibm | amigados newsos*
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alliant | amdahl intel | aout nindy*
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arm | aout isi | bout osf*
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c1 | apollo little | bsd* sco*
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c2 | att mips | coff sunos*
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cray2 | bcs motorola | ctix* svr4
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h8300 | bout ncr | dgux* sym*
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i386 | bull next | dynix* sysv*
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i860 | cbm nyu | ebmon ultrix*
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i960 | coff sco | esix* unicos*
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m68000 | convergent sequent | hds unos*
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m68k | convex sgi | hpux* uts
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m88k | cray sony | irix* v88r*
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mips | dec sun | isc* vms*
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ns32k | encore unicom | kern vxworks*
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pyramid | gould utek | mach*
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romp | hitachi wrs |
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rs6000 | |
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sparc | |
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tahoe | |
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tron | |
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vax | |
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xmp | |
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ymp | |
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*Warning:* `configure' can represent a very large number of
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combinations of architecture, vendor, and OS. There is by no
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means support available for all possible combinations!
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The `configure' script accompanying GDB 4.4 does not provide any
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query facility to list all supported host and target names or aliases.
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`configure' calls the Bourne shell script `config.sub' to map
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abbreviations to full names; you can read the script, if you wish, or
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you can use it to test your guesses on abbreviations--for example:
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% sh config.sub sun4
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sparc-sun-sunos4
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% sh config.sub sun3
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m68k-sun-sunos4
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% sh config.sub decstation
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mips-dec-ultrix
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% sh config.sub hp300bsd
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m68k-hp-bsd
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% sh config.sub i386v
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i386-none-sysv
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% sh config.sub i486v
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*** Configuration "i486v" not recognized
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`config.sub' is also distributed in the directory `gdb-4.4'.
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`configure' Options
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===================
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Here is a summary of all the `configure' options and arguments that
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you might use for building GDB:
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configure [+destdir=DIR] [+subdirs]
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[+objdir=ALTROOT] [+norecursion] [+rm]
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[+target=TARGET...] HOST...
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You may introduce options with the character `-' rather than `+' if
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you prefer; but you may abbreviate option names if you use `+'.
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`+destdir=DIR'
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DIR is an installation directory *path prefix*. After you
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configure with this option, `make install' will install GDB as
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`DIR/bin/gdb', and the libraries in `DIR/lib'. If you specify
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`+destdir=/usr/local', for example, `make install' creates
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`/usr/local/bin/gdb'.
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`+subdirs'
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Write configuration specific files in subdirectories of the form
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H-HOST/T-TARGET
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(and configure the `Makefile' to generate object code in
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subdirectories of this form as well). Without this option, if you
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specify only one configuration for GDB, `configure' will use the
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same directory for source, configured files, and binaries. This
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option is used automatically if you specify more than one HOST or
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more than one `+target=TARGET' option on the `configure' command
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line.
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`+norecursion'
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Configure only the directory where `configure' is executed; do not
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propagate configuration to subdirectories.
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`+objdir=ALTROOT'
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ALTROOT is an alternative directory used as the root for
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configured files. `configure' will create directories under
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ALTROOT in parallel to the source directories. If you use
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`+objdir=ALTROOT' with `+subdirs', `configure' also builds the
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`H-HOST/T-TARGET' subdirectories in the directory tree rooted in
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ALTROOT.
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`+rm'
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Remove the configuration that the other arguments specify.
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`+target=TARGET ...'
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Configure GDB for cross-debugging programs running on each
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specified TARGET. You may specify as many `+target' options as
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you wish. Without this option, GDB is configured to debug
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programs that run on the same machine (HOST) as GDB itself.
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There is no convenient way to generate a list of all available
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targets.
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`HOST ...'
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Configure GDB to run on each specified HOST. You may specify as
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many host names as you wish.
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There is no convenient way to generate a list of all available
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hosts.
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`configure' accepts other options, for compatibility with configuring
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other GNU tools recursively; but these are the only options that
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affect GDB or its supporting libraries.
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Languages other than C
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C++ support has been integrated into gdb. Partial Modula-2 support is
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now in GDB. GDB should work with FORTRAN programs. (If you have
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problems, please send a bug report; you may have to refer to some
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FORTRAN variables with a trailing underscore). I am not aware of
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anyone who is working on getting gdb to use the syntax of any other
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language. Pascal programs which use sets, subranges, file variables,
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or nested functions will not currently work.
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Kernel debugging
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I have't done this myself so I can't really offer any advice.
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Remote debugging over serial lines works fine, but the kernel debugging
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code in here has not been tested in years. Van Jacobson claims to have
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better kernel debugging.
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Remote debugging
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The files m68k-stub.c and i386-stub.c contain two examples of remote
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stubs to be used with remote.c. They are designeded to run standalone
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on a 68k or 386 cpu and communicate properly with the remote.c stub
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over a serial line.
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The file rem-multi.shar contains a general stub that can probably
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run on various different flavors of unix to allow debugging over a
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serial line from one machine to another.
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Some working remote interfaces for talking to existing ROM monitors
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are:
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remote-eb.c AMD 29000 "EBMON"
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remote-nindy.c Intel 960 "Nindy"
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remote-adapt.c AMD 29000 "Adapt"
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remote-mm.c AMD 29000 "minimon"
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Remote-vx.c and the vx-share subdirectory contain a remote interface for the
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VxWorks realtime kernel, which communicates over TCP using the Sun
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RPC library. This would be a useful starting point for other remote-
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via-ethernet back ends.
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Reporting Bugs
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The correct address for reporting bugs found in gdb is
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"bug-gdb@prep.ai.mit.edu". Please email all bugs to that address.
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Please include the GDB version number (e.g. gdb-4.4), and how
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you configured it (e.g. "sun4" or "mach386 host, i586-intel-synopsys
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target").
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A known bug:
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* If you run with a watchpoint enabled, breakpoints will become
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erratic and might not stop the program. Disabling or deleting the
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watchpoint will fix the problem.
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GDB can produce warnings about symbols that it does not understand. By
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default, these warnings are disabled. You can enable them by executing
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`set complaint 10' (which you can put in your ~/.gdbinit if you like).
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I recommend doing this if you are working on a compiler, assembler,
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linker, or gdb, since it will point out problems that you may be able
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to fix. Warnings produced during symbol reading indicate some mismatch
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between the object file and GDB's symbol reading code. In many cases,
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it's a mismatch between the specs for the object file format, and what
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the compiler actually outputs or the debugger actually understands.
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If you port gdb to a new machine, please send the required changes to
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bug-gdb@prep.ai.mit.edu. There's lots of information about doing your
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own port in the file gdb-4.4/gdb/doc/gdbint.texinfo, which you can
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print out, or read with `info' (see the Makefile.in there). If your
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changes are more than a few lines, obtain and send in a copyright
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assignment from gnu@prep.ai.mit.edu, as described in the section
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`Writing Code for GDB'.
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X Windows versus GDB
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xgdb is obsolete. We are not doing any development or support of it.
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There is an "xxgdb", which shows more promise, which was posted to
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comp.sources.x.
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For those intersted in auto display of source and the availability of
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an editor while debugging I suggest trying gdb-mode in gnu-emacs
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(Try typing M-x gdb RETURN). Comments on this mode are welcome.
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Writing Code for GDB
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We appreciate having users contribute code that is of general use, but
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for it to be included in future GDB releases it must be cleanly
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written. We do not want to include changes that will needlessly make
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future maintainance difficult. It is not much harder to do things
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right, and in the long term it is worth it to the GNU project, and
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probably to you individually as well.
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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
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changes actually work, or even before you start them, because a manager
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or lawyer on your end will probably make this a slow process.
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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.
|
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Please try to avoid making machine-specific changes to
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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:
|