GCC requires that various tools and packages be available for use in the build procedure. Modifying GCC sources requires additional tools described below.
Necessary to bootstrap GCC, although versions of GCC prior to 4.8 also allow bootstrapping with a ISO C89 compiler and versions of GCC prior to 3.4 also allow bootstrapping with a traditional (K&R) C compiler.
To build all languages in a cross-compiler or other configuration where 3-stage bootstrap is not performed, you need to start with an existing GCC binary (version 3.4 or later) because source code for language frontends other than C might use GCC extensions.
Note that to bootstrap GCC with versions of GCC earlier than 3.4, you may need to use --disable-stage1-checking, though bootstrapping the compiler with such earlier compilers is strongly discouraged.
In order to build GCC, the C standard library and headers must be present for all target variants for which target libraries will be built (and not only the variant of the host C++ compiler).
This affects the popular ‘x86_64-pc-linux-gnu’ platform (among other multilib targets), for which 64-bit (‘x86_64’) and 32-bit (‘i386’) libc headers are usually packaged separately. If you do a build of a native compiler on ‘x86_64-pc-linux-gnu’, make sure you either have the 32-bit libc developer package properly installed (the exact name of the package depends on your distro) or you must build GCC as a 64-bit only compiler by configuring with the option --disable-multilib. Otherwise, you may encounter an error such as ‘fatal error: gnu/stubs-32.h: No such file’
In order to build GNAT, the Ada compiler, you need a working GNAT compiler (GCC version 4.7 or later).
This includes GNAT tools such as gnatmake and
gnatlink, since the Ada front end is written in Ada and
uses some GNAT-specific extensions.
In order to build a cross compiler, it is strongly recommended to install the new compiler as native first, and then use it to build the cross compiler. Other native compiler versions may work but this is not guaranteed and will typically fail with hard to understand compilation errors during the build.
Similarly, it is strongly recommended to use an older version of GNAT to build GNAT. More recent versions of GNAT than the version built are not guaranteed to work and will often fail during the build with compilation errors.
Note that configure does not test whether the GNAT installation works
and has a sufficiently recent version; if too old a GNAT version is
installed and --enable-languages=ada is used, the build will fail.
ADA_INCLUDE_PATH and ADA_OBJECT_PATH environment variables
must not be set when building the Ada compiler, the Ada tools, or the
Ada runtime libraries. You can check that your build environment is clean
by verifying that ‘gnatls -v’ lists only one explicit path in each
section.
Necessary when running configure because some
/bin/sh shells have bugs and may crash when configuring the
target libraries. In other cases, /bin/sh or ksh
have disastrous corner-case performance problems. This
can cause target configure runs to literally take days to
complete in some cases.
So on some platforms /bin/ksh is sufficient, on others it
isn’t. See the host/target specific instructions for your platform, or
use bash to be sure. Then set CONFIG_SHELL in your
environment to your “good” shell prior to running
configure/make.
zsh is not a fully compliant POSIX shell and will not
work when configuring GCC.
Necessary for creating some of the generated source files for GCC. If in doubt, use a recent GNU awk version, as some of the older ones are broken. GNU awk version 3.1.5 is known to work.
Necessary in some circumstances, optional in others. See the host/target specific instructions for your platform for the exact requirements.
Necessary to uncompress GCC tar files when source code is
obtained via HTTPS mirror sites.
You must have GNU make installed to build GCC.
Necessary (only on some platforms) to untar the source code. Many
systems’ tar programs will also work, only try GNU
tar if you have problems.
Necessary when targeting Darwin, building ‘libstdc++’,
and not using --disable-symvers.
Necessary when targeting Solaris 2 with Solaris ld and not using
--disable-symvers.
Necessary when regenerating Makefile dependencies in libiberty. Necessary when regenerating libiberty/functions.texi. Necessary when generating manpages from Texinfo manuals. Used by various scripts to generate some files included in the source repository (mainly Unicode-related and rarely changing) from source tables.
Used by automake.
Several support libraries are necessary to build GCC, some are required, others optional. While any sufficiently new version of required tools usually work, library requirements are generally stricter. Newer versions may work in some cases, but it’s safer to use the exact versions documented. We appreciate bug reports about problems with newer versions, though. If your OS vendor provides packages for the support libraries then using those packages may be the simplest way to install the libraries.
Necessary to build GCC. If a GMP source distribution is found in a subdirectory of your GCC sources named gmp, it will be built together with GCC. Alternatively, if GMP is already installed but it is not in your library search path, you will have to configure with the --with-gmp configure option. See also --with-gmp-lib and --with-gmp-include. The in-tree build is only supported with the GMP version that download_prerequisites installs.
Necessary to build GCC. It can be downloaded from https://www.mpfr.org. If an MPFR source distribution is found in a subdirectory of your GCC sources named mpfr, it will be built together with GCC. Alternatively, if MPFR is already installed but it is not in your default library search path, the --with-mpfr configure option should be used. See also --with-mpfr-lib and --with-mpfr-include. The in-tree build is only supported with the MPFR version that download_prerequisites installs.
Necessary to build GCC. It can be downloaded from http://www.multiprecision.org/mpc/. If an MPC source distribution is found in a subdirectory of your GCC sources named mpc, it will be built together with GCC. Alternatively, if MPC is already installed but it is not in your default library search path, the --with-mpc configure option should be used. See also --with-mpc-lib and --with-mpc-include. The in-tree build is only supported with the MPC version that download_prerequisites installs.
Necessary to build GCC with the Graphite loop optimizations. It can be downloaded from https://gcc.gnu.org/pub/gcc/infrastructure/. If an isl source distribution is found in a subdirectory of your GCC sources named isl, it will be built together with GCC. Alternatively, the --with-isl configure option should be used if isl is not installed in your default library search path.
Necessary to build GCC with zstd compression used for LTO bytecode. The library is searched in your default library patch search. Alternatively, the --with-zstd configure option should be used.
Necessary when modifying configure.ac, aclocal.m4, etc. to regenerate configure and config.in files.
Necessary when modifying a Makefile.am file to regenerate its associated Makefile.in.
Much of GCC does not use automake, so directly edit the Makefile.in file. Specifically this applies to the gcc, intl, libcpp, libiberty, libobjc directories as well as any of their subdirectories.
For directories that use automake, GCC requires the latest release in the 1.15 series, which is currently 1.15.1. When regenerating a directory to a newer version, please update all the directories using an older 1.15 to the latest released version.
Needed to regenerate gcc.pot.
Necessary when modifying gperf input files, e.g.
gcc/cp/cfns.gperf to regenerate its associated header file, e.g.
gcc/cp/cfns.h.
Necessary to run the GCC testsuite; see the section on testing for details.
Necessary to regenerate fixinc/fixincl.x from fixinc/inclhack.def and fixinc/*.tpl.
Necessary to run ‘make check’ for fixinc.
Necessary to regenerate the top level Makefile.in file from Makefile.tpl and Makefile.def.
Necessary when modifying *.l files.
Necessary to build GCC during development because the generated output files are not included in the version-controlled source repository. They are included in releases.
Necessary for running makeinfo when modifying *.texi
files to test your changes.
Necessary for running make dvi or make pdf to
create printable documentation in DVI or PDF format. Texinfo version
4.8 or later is required for make pdf.
Necessary to build GCC documentation during development because the generated output files are not included in the repository. They are included in releases.
Necessary for running texi2dvi and texi2pdf, which
are used when running make dvi or make pdf to create
DVI or PDF files, respectively.
Necessary to regenerate jit/docs/_build/texinfo from the .rst files in the directories below jit/docs.
Necessary to access the source repository. Public releases and weekly snapshots of the development sources are also available via HTTPS.
Useful when submitting patches for the GCC source code.
Necessary when applying patches, created with diff, to one’s
own sources.