README for GDB release This is GDB, the GNU source-level debugger. A summary of new features is in the file `gdb/NEWS'. Check the GDB home page at http://www.gnu.org/software/gdb/ for up to date release information, mailing list links and archives, etc. GDB's bug tracking data base can be found at http://www.gnu.org/software/gdb/bugs/ Unpacking and Installation -- quick overview ========================== The release is provided as a gzipped tar file called 'gdb-VERSION.tar.gz', where VERSION is the version of GDB. 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-VERSION directory. The idea is that a variety of GNU tools can share a common copy of these things. Be aware of variation over time--for example don't try to build GDB with a copy of bfd from a release other than the GDB release (such as a binutils release), especially if the releases are more than a few weeks apart. Configuration scripts and makefiles exist to cruise up and down this directory tree and automatically build all the pieces in the right order. When you unpack the gdb-VERSION.tar.gz file, it will create a source directory called `gdb-VERSION'. You can build GDB right in the source directory: cd gdb-VERSION ./configure --prefix=/usr/local (or wherever you want) make all install However, we recommend that an empty directory be used instead. This way you do not clutter your source tree with binary files and will be able to create different builds with different configuration options. You can build GDB in any empty build directory: mkdir build cd build /gdb-VERSION/configure [etc...] make all install (Building GDB with DJGPP tools for MS-DOS/MS-Windows is slightly different; see the file gdb-VERSION/gdb/config/djgpp/README for details.) This will configure and build all the libraries as well as GDB. If `configure' can't determine your system type, specify one as its argument, e.g., `./configure sun4' or `./configure decstation'. Make sure that your 'configure' line ends in 'gdb-VERSION/configure': /berman/migchain/source/gdb-VERSION/configure # RIGHT /berman/migchain/source/gdb-VERSION/gdb/configure # WRONG The GDB package contains several subdirectories, such as 'gdb', 'bfd', and 'readline'. If your 'configure' line ends in 'gdb-VERSION/gdb/configure', then you are configuring only the gdb subdirectory, not the whole GDB package. This leads to build errors such as: make: *** No rule to make target `../bfd/bfd.h', needed by `gdb.o'. Stop. If you get other compiler errors during this stage, see the `Reporting Bugs' section below; there are a few known problems. GDB's `configure' script has many options to enable or disable different features or dependencies. These options are not generally known to the top-level `configure', so if you want to see a complete list of options, invoke the subdirectory `configure', like: /berman/migchain/source/gdb-VERSION/gdb/configure --help (Take note of how this differs from the invocation used to actually configure the build tree.) GDB requires a C++11 compiler. If you do not have a C++11 compiler for your system, you may be able to download and install the GNU CC compiler. It is available via anonymous FTP from the directory `ftp://ftp.gnu.org/pub/gnu/gcc'. GDB also requires an ISO C standard library. The GDB remote server, GDBserver, builds with some non-ISO standard libraries - e.g. for Windows CE. GDB can optionally be built against various external libraries. These dependencies are described below in the "`configure options" section of this README. GDB can be used as a cross-debugger, running on a machine of one type while debugging a program running on a machine of another type. See below. More Documentation ****************** 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/doc' subdirectory. The main Info file is `gdb-VERSION/gdb/doc/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-VERSION'), you can make the Info file by typing: cd gdb/doc make info If you want to typeset and print copies of this manual, you need TeX, a program to print its DVI output files, and `texinfo.tex', the Texinfo definitions file. This file is included in the GDB distribution, in the directory `gdb-VERSION/texinfo'. TeX is a 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 (for PostScript devices) 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/texinfo' directory. If you have TeX and a DVI printer program installed, you can typeset and print this manual. First switch to the `gdb' subdirectory of the main source directory (for example, to `gdb-VERSION/gdb') and then type: make doc/gdb.dvi If you prefer to have the manual in PDF format, type this from the `gdb/doc' subdirectory of the main source directory: make gdb.pdf For this to work, you will need the PDFTeX package to be installed. 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. That directory contains: `gdb-VERSION/{COPYING,COPYING.LIB}' Standard GNU license files. Please read them. `gdb-VERSION/bfd' source for the Binary File Descriptor library `gdb-VERSION/config*' script for configuring GDB, along with other support files `gdb-VERSION/gdb' the source specific to GDB itself `gdb-VERSION/include' GNU include files `gdb-VERSION/libiberty' source for the `-liberty' free software library `gdb-VERSION/opcodes' source for the library of opcode tables and disassemblers `gdb-VERSION/readline' source for the GNU command-line interface NOTE: The readline library is compiled for use by GDB, but will not be installed on your system when "make install" is issued. `gdb-VERSION/sim' source for some simulators (ARM, D10V, SPARC, M32R, MIPS, PPC, V850, etc) `gdb-VERSION/texinfo' The `texinfo.tex' file, which you need in order to make a printed manual using TeX. `gdb-VERSION/etc' Coding standards, useful files for editing GDB, and other miscellanea. Note: the following instructions are for building GDB on Unix or Unix-like systems. Instructions for building with DJGPP for MS-DOS/MS-Windows are in the file gdb/config/djgpp/README. The simplest way to configure and build GDB is to run `configure' from the `gdb-VERSION' directory. First switch to the `gdb-VERSION' source directory if you are not already in it; then run `configure'. For example: cd gdb-VERSION ./configure make Running `configure' followed by `make' builds the `bfd', `readline', `mmalloc', and `libiberty' libraries, then `gdb' itself. The configured source files, and the binaries, are left in the corresponding source directories. `configure' is a Bourne-shell (`/bin/sh') script; if your system does not recognize this automatically when you run a different shell, you may need to run `sh' on it explicitly: sh configure If you run `configure' from a directory that contains source directories for multiple libraries or programs, `configure' creates configuration files for every directory level underneath (unless you tell it not to, with the `--norecursion' option). 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 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 correctly (GNU `make' and SunOS 'make' are two that should), running `make' in each of these directories builds the `gdb' program specified there. To build `gdb' in a separate directory, run `configure' with the `--srcdir' option to specify where to find the source. (You also need to specify a path to find `configure' itself from your working directory. If the path to `configure' would be the same as the argument to `--srcdir', you can leave out the `--srcdir' option; it will be assumed.) For example, you can build GDB in a separate directory for a Sun 4 like this: cd gdb-VERSION mkdir ../gdb-sun4 cd ../gdb-sun4 ../gdb-VERSION/configure make When `configure' builds a configuration using a remote source directory, it creates a tree for the binaries with the same structure (and using the same names) as the tree under the source directory. In the example, you'd find the Sun 4 library `libiberty.a' in the directory `gdb-sun4/libiberty', and GDB itself in `gdb-sun4/gdb'. One popular reason to build several GDB configurations in separate directories is to configure GDB for cross-compiling (where GDB runs on one machine--the host--while debugging programs that run on another machine--the target). You specify a cross-debugging target by giving the `--target=TARGET' option to `configure'. When you run `make' to build a program or library, you must run it in a configured directory--whatever directory you were in when you called `configure' (or one of its subdirectories). The `Makefile' that `configure' generates in each source directory also runs recursively. If you type `make' in a source directory such as `gdb-VERSION' (or in a separate configured directory configured with `--srcdir=PATH/gdb-VERSION'), you will build all the required libraries, and 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. 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-sunos4.1.1 % sh config.sub sun3 m68k-sun-sunos4.1.1 % sh config.sub decstation mips-dec-ultrix4.2 % sh config.sub hp300bsd m68k-hp-bsd % sh config.sub i386v i386-pc-sysv % sh config.sub i786v Invalid configuration `i786v': machine `i786v' not recognized `config.sub' is also distributed in the GDB source directory. `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. There are many options to gdb's `configure' script, some of which are only useful in special situation. *note : (autoconf.info)Running configure scripts, for a full explanation of `configure'. configure [--help] [--prefix=DIR] [--srcdir=PATH] [--target=TARGET] [--host=HOST] [HOST] You may introduce options with a single `-' rather than `--' if you prefer; but you may abbreviate option names if you use `--'. Some more obscure GDB `configure' options are not listed here. `--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 compatibly 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. `--host=HOST' Configure GDB to run on the specified HOST. There is no convenient way to generate a list of all available hosts. `HOST ...' Same as `--host=HOST'. If you omit this, GDB will guess; it's quite accurate. `--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. `--enable-targets=TARGET,TARGET,...' `--enable-targets=all` Configure GDB for cross-debugging programs running on the specified list of targets. The special value `all' configures GDB for debugging programs running on any target it supports. `--with-gdb-datadir=PATH' Set the GDB-specific data directory. GDB will look here for certain supporting files or scripts. This defaults to the `gdb' subdirectory of `datadir' (which can be set using `--datadir'). `--with-relocated-sources=DIR' Sets up the default source path substitution rule so that directory names recorded in debug information will be automatically adjusted for any directory under DIR. DIR should be a subdirectory of GDB's configured prefix, the one mentioned in the `--prefix' or `--exec-prefix' options to configure. This option is useful if GDB is supposed to be moved to a different place after it is built. `--enable-64-bit-bfd' Enable 64-bit support in BFD on 32-bit hosts. `--disable-gdbmi' Build GDB without the GDB/MI machine interface. `--enable-tui' Build GDB with the text-mode full-screen user interface (TUI). Requires a curses library (ncurses and cursesX are also supported). `--with-curses' Use the curses library instead of the termcap library, for text-mode terminal operations. `--with-debuginfod' Build GDB with libdebuginfod, the debuginfod client library. Used to automatically fetch source files and separate debug files from debuginfod servers using the associated executable's build ID. Enabled by default if libdebuginfod is installed and found at configure time. debuginfod is packaged with elfutils, starting with version 0.178. You can get the latest version from 'https://sourceware.org/elfutils/'. `--with-libunwind-ia64' Use the libunwind library for unwinding function call stack on ia64 target platforms. See http://www.nongnu.org/libunwind/index.html for details. `--with-system-readline' Use the readline library installed on the host, rather than the library supplied as part of GDB. Readline 7 or newer is required; this is enforced by the build system. `--with-system-zlib Use the zlib library installed on the host, rather than the library supplied as part of GDB. `--with-expat' Build GDB with Expat, a library for XML parsing. (Done by default if libexpat is installed and found at configure time.) This library is used to read XML files supplied with GDB. If it is unavailable, some features, such as remote protocol memory maps, target descriptions, and shared library lists, that are based on XML files, will not be available in GDB. If your host does not have libexpat installed, you can get the latest version from `http://expat.sourceforge.net'. `--with-libiconv-prefix[=DIR]' Build GDB with GNU libiconv, a character set encoding conversion library. This is not done by default, as on GNU systems the `iconv' that is built in to the C library is sufficient. If your host does not have a working `iconv', you can get the latest version of GNU iconv from `https://www.gnu.org/software/libiconv/'. GDB's build system also supports building GNU libiconv as part of the overall build. See the GDB manual instructions on how to do this. `--with-lzma' Build GDB with LZMA, a compression library. (Done by default if liblzma is installed and found at configure time.) LZMA is used by GDB's "mini debuginfo" feature, which is only useful on platforms using the ELF object file format. If your host does not have liblzma installed, you can get the latest version from `https://tukaani.org/xz/'. `--with-gmp=DIR' `--with-gmp-lib=LIBDIR' `--with-gmp-include=INCDIR' Build GDB using the GMP library installed at the directory DIR. If your host does not have GMP installed, you can get the latest version at `https://gmplib.org/'. The `--with-gmp=gmpinstalldir` option is shorthand for `--with-gmp-lib=gmpinstalldir/lib` and `--with-gmp-include=gmpinstalldir/include`. `--with-mpfr=DIR' `--with-mpfr-lib=LIBDIR' `--with-mpfr-include=INCDIR' Build GDB using GNU MPFR installed at the directory DIR, a library for multiple-precision floating-point computation with correct rounding. This library is used to emulate target floating-point arithmetic during expression evaluation when the target uses different floating-point formats than the host. If your host does not have GNU MPFR installed, you can get the latest version from `https://www.mpfr.org/'. The `--with-mpfr=mpfrinstalldir` option is shorthand for `--with-mpfr-lib=mpfrinstalldir/lib` and `--with-mpfr-include=mpfrinstalldir/include`. `--with-python[=PYTHON]' Build GDB with Python scripting support. (Done by default if libpython is present and found at configure time.) Python makes GDB scripting much more powerful than the restricted CLI scripting language. If your host does not have Python installed, you can find it on `http://www.python.org/download/'. The oldest version of Python supported by GDB is 3.2. The optional argument PYTHON is used to find the Python headers and libraries. It can be either the name of a Python executable, or the name of the directory in which Python is installed. `--with-guile[=GUILE]' Build GDB with GNU Guile scripting support. (Done by default if libguile is present and found at configure time.) If your host does not have Guile installed, you can find it at `https://www.gnu.org/software/guile/'. The optional argument GUILE can be a version number, which will cause `configure' to try to use that version of Guile; or the file name of a `pkg-config' executable, which will be queried to find the information needed to compile and link against Guile. `--enable-source-highlight' When printing source code, use source highlighting. This requires libsource-highlight to be installed and is enabled by default if the library is found. `--with-xxhash' Use libxxhash for hashing. This has no user-visible effect but speeds up various GDB operations such as symbol loading. Enabled by default if libxxhash is found. `--with-amd-dbgapi=[auto,yes,no]' Whether to use the amd-dbgapi library to support local debugging of AMD GCN architecture GPUs. When explicitly requesting support for an AMD GCN architecture through `--enable-targets' or `--target', there is no need to use `--with-amd-dbgapi': `configure' will automatically look for the amd-dbgapi library and fail if not found. When using --enable-targets=all, support for the AMD GCN architecture will only be included if the amd-dbgapi is found. `--with-amd-dbgapi=yes' can be used to make it a failure if the amd-dbgapi library is not found. `--with-amd-dbgapi=no' can be used to prevent looking for the amd-dbgapi library altogether. `--without-included-regex' Don't use the regex library included with GDB (as part of the libiberty library). This is the default on hosts with version 2 of the GNU C library. `--with-sysroot=DIR' Use DIR as the default system root directory for libraries whose file names begin with `/lib' or `/usr/lib'. (The value of DIR can be modified at run time by using the "set sysroot" command.) If DIR is under the GDB configured prefix (set with `--prefix' or `--exec-prefix' options), the default system root will be automatically adjusted if and when GDB is moved to a different location. `--with-system-gdbinit=FILE' Configure GDB to automatically load a system-wide init file. FILE should be an absolute file name. If FILE is in a directory under the configured prefix, and GDB is moved to another location after being built, the location of the system-wide init file will be adjusted accordingly. `--with-system-gdbinit-dir=DIR' Configure GDB to automatically load system-wide init files from a directory. Files with extensions `.gdb', `.py' (if Python support is enabled) and `.scm' (if Guile support is enabled) are supported. DIR should be an absolute directory name. If DIR is in a directory under the configured prefix, and GDB is moved to another location after being built, the location of the system- wide init directory will be adjusted accordingly. `--enable-build-warnings' When building the GDB sources, ask the compiler to warn about any code which looks even vaguely suspicious. It passes many different warning flags, depending on the exact version of the compiler you are using. `--enable-werror' Treat compiler warnings as werrors. It adds the -Werror flag to the compiler, which will fail the compilation if the compiler outputs any warning messages. `--enable-ubsan' Enable the GCC undefined behavior sanitizer. By default this is disabled in GDB releases, but enabled when building from git. The undefined behavior sanitizer checks for C++ undefined behavior. It has a performance cost, so if you are looking at GDB's performance, you should disable it. `--enable-unit-tests[=yes|no]' Enable (i.e., include) support for unit tests when compiling GDB and GDBServer. Note that if this option is not passed, GDB will have selftests if it is a development build, and will *not* have selftests if it is a non-development build. `configure' accepts other options, for compatibility with configuring other GNU tools recursively. Remote debugging ================= The files m68k-stub.c, i386-stub.c, and sparc-stub.c are examples of remote stubs to be used with remote.c. They are designed to run standalone on an m68k, i386, or SPARC cpu and communicate properly with the remote.c stub over a serial line. The directory gdbserver/ contains `gdbserver', a program that allows remote debugging for Unix applications. GDBserver is only supported for some native configurations. The file gdbserver/README includes further notes on GDBserver; in particular, it explains how to build GDBserver for cross-debugging (where GDBserver runs on the target machine, which is of a different architecture than the host machine running GDB). Reporting Bugs in GDB ===================== There are several ways of reporting bugs in GDB. The prefered method is to use the World Wide Web: http://www.gnu.org/software/gdb/bugs/ As an alternative, the bug report can be submitted, via e-mail, to the address "bug-gdb@gnu.org". When submitting a bug, please include the GDB version number, and how you configured it (e.g., "sun4" or "mach386 host, i586-intel-synopsys target"). Since GDB supports so many different configurations, it is important that you be precise about this. The simplest way to do this is to include the output from these commands: % gdb --version % gdb --config For more information on how/whether to report bugs, see the Reporting Bugs chapter of the GDB manual (gdb/doc/gdb.texinfo). Graphical interface to GDB -- X Windows, MS Windows ========================== Several graphical interfaces to GDB are available. You should check: https://sourceware.org/gdb/wiki/GDB%20Front%20Ends for an up-to-date list. Emacs users will very likely enjoy the Grand Unified Debugger mode; try typing `M-x gdb RET'. Writing Code for GDB ===================== There is information about writing code for GDB in the file `CONTRIBUTE' and at the website: http://www.gnu.org/software/gdb/ in particular in the wiki. If you are pondering writing anything but a short patch, especially take note of the information about copyrights and copyright assignment. It can take quite a while to get all the paperwork done, so we encourage you to start that process as soon as you decide you are planning to work on something, or at least well ahead of when you think you will be ready to submit the patches. GDB Testsuite ============= Included with the GDB distribution is a DejaGNU based testsuite that can either be used to test your newly built GDB, or for regression testing a GDB with local modifications. Running the testsuite requires the prior installation of DejaGNU, which is generally available via ftp. The directory ftp://sources.redhat.com/pub/dejagnu/ will contain a recent snapshot. Once DejaGNU is installed, you can run the tests in one of the following ways: (1) cd gdb-VERSION make check-gdb or (2) cd gdb-VERSION/gdb make check or (3) cd gdb-VERSION/gdb/testsuite make site.exp (builds the site specific file) runtest -tool gdb GDB=../gdb (or GDB= as appropriate) When using a `make'-based method, you can use the Makefile variable `RUNTESTFLAGS' to pass flags to `runtest', e.g.: make RUNTESTFLAGS=--directory=gdb.cp check If you use GNU make, you can use its `-j' option to run the testsuite in parallel. This can greatly reduce the amount of time it takes for the testsuite to run. In this case, if you set `RUNTESTFLAGS' then, by default, the tests will be run serially even under `-j'. You can override this and force a parallel run by setting the `make' variable `FORCE_PARALLEL' to any non-empty value. Note that the parallel `make check' assumes that you want to run the entire testsuite, so it is not compatible with some dejagnu options, like `--directory'. The last method gives you slightly more control in case of problems with building one or more test executables or if you are using the testsuite `standalone', without it being part of the GDB source tree. See the DejaGNU documentation for further details. Copyright and License Notices ============================= Most files maintained by the GDB Project contain a copyright notice as well as a license notice, usually at the start of the file. To reduce the length of copyright notices, consecutive years in the copyright notice can be combined into a single range. For instance, the following list of copyright years... 1986, 1988, 1989, 1991-1993, 1999, 2000, 2007, 2008, 2009, 2010, 2011 ... is abbreviated into: 1986, 1988-1989, 1991-1993, 1999-2000, 2007-2011 Every year of each range, inclusive, is a copyrightable year that could be listed individually. (this is for editing this file with GNU emacs) Local Variables: mode: text End: