re PR c/13110 (error message includes extra blank line)

[thirdparty/gcc.git] / gcc / doc / install.texi

\input texinfo.tex    @c -*-texinfo-*-
@c @ifnothtml
@c %**start of header
@setfilename gccinstall.info
@settitle Installing GCC
@setchapternewpage odd
@c %**end of header
@c @end ifnothtml

@c Specify title for specific html page
@ifset indexhtml
@settitle Installing GCC
@end ifset
@ifset specifichtml
@settitle Host/Target specific installation notes for GCC
@end ifset
@ifset prerequisiteshtml
@settitle Prerequisites for GCC
@end ifset
@ifset downloadhtml
@settitle Downloading GCC
@end ifset
@ifset configurehtml
@settitle Installing GCC: Configuration
@end ifset
@ifset buildhtml
@settitle Installing GCC: Building
@end ifset
@ifset testhtml
@settitle Installing GCC: Testing
@end ifset
@ifset finalinstallhtml
@settitle Installing GCC: Final installation
@end ifset
@ifset binarieshtml
@settitle Installing GCC: Binaries
@end ifset
@ifset oldhtml
@settitle Installing GCC: Old documentation
@end ifset
@ifset gfdlhtml
@settitle Installing GCC: GNU Free Documentation License
@end ifset

@c Copyright (C) 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
@c 1999, 2000, 2001, 2002, 2003 Free Software Foundation, Inc.
@c *** Converted to texinfo by Dean Wakerley, dean@wakerley.com

@c Include everything if we're not making html
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@set prerequisiteshtml
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@set configurehtml
@set buildhtml
@set testhtml
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@c Part 2 Summary Description and Copyright
@copying
Copyright @copyright{} 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
1999, 2000, 2001, 2002, 2003 Free Software Foundation, Inc.
@sp 1
Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.2 or
any later version published by the Free Software Foundation; with no
Invariant Sections, the Front-Cover texts being (a) (see below), and
with the Back-Cover Texts being (b) (see below).  A copy of the
license is included in the section entitled ``@uref{./gfdl.html,,GNU
Free Documentation License}''.

(a) The FSF's Front-Cover Text is:

     A GNU Manual

(b) The FSF's Back-Cover Text is:

     You have freedom to copy and modify this GNU Manual, like GNU
     software.  Copies published by the Free Software Foundation raise
     funds for GNU development.
@end copying
@ifinfo
@insertcopying
@end ifinfo

@c Part 3 Titlepage and Copyright
@titlepage
@sp 10
@comment The title is printed in a large font.
@center @titlefont{Installing GCC}

@c The following two commands start the copyright page.
@page
@vskip 0pt plus 1filll
@insertcopying
@end titlepage

@c Part 4 Top node and Master Menu
@ifinfo
@node    Top, , , (dir)
@comment node-name, next,          Previous, up

@menu
* Installing GCC::  This document describes the generic installation
                    procedure for GCC as well as detailing some target
                    specific installation instructions.

* Specific::        Host/target specific installation notes for GCC.
* Binaries::        Where to get pre-compiled binaries.

* Old::             Old installation documentation.

* GNU Free Documentation License:: How you can copy and share this manual.
* Concept Index::   This index has two entries.
@end menu
@end ifinfo

@c Part 5 The Body of the Document
@c ***Installing GCC**********************************************************
@ifnothtml
@comment node-name,     next,          previous, up
@node    Installing GCC, Binaries, , Top
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@ifset indexhtml
@ifnothtml
@chapter Installing GCC
@end ifnothtml

The latest version of this document is always available at
@uref{http://gcc.gnu.org/install/,,http://gcc.gnu.org/install/}.

This document describes the generic installation procedure for GCC as well
as detailing some target specific installation instructions.

GCC includes several components that previously were separate distributions
with their own installation instructions.  This document supersedes all
package specific installation instructions.

@emph{Before} starting the build/install procedure please check the
@ifnothtml
@ref{Specific, host/target specific installation notes}.
@end ifnothtml
@ifhtml
@uref{specific.html,,host/target specific installation notes}.
@end ifhtml
We recommend you browse the entire generic installation instructions before
you proceed.

Lists of successful builds for released versions of GCC are
available at @uref{http://gcc.gnu.org/buildstat.html}. 
These lists are updated as new information becomes available.

The installation procedure itself is broken into five steps.

@ifinfo
@menu
* Prerequisites::
* Downloading the source::
* Configuration::
* Building::
* Testing:: (optional)
* Final install::
@end menu
@end ifinfo
@ifhtml
@enumerate
@item
@uref{prerequisites.html,,Prerequisites}
@item
@uref{download.html,,Downloading the source}
@item
@uref{configure.html,,Configuration}
@item
@uref{build.html,,Building}
@item
@uref{test.html,,Testing} (optional)
@item
@uref{finalinstall.html,,Final install}
@end enumerate
@end ifhtml

Please note that GCC does not support @samp{make uninstall} and probably
won't do so in the near future as this would open a can of worms.  Instead,
we suggest that you install GCC into a directory of its own and simply
remove that directory when you do not need that specific version of GCC
any longer, and, if shared libraries are installed there as well, no
more binaries exist that use them.

@ifhtml
There are also some @uref{old.html,,old installation instructions},
which are mostly obsolete but still contain some information which has
not yet been merged into the main part of this manual.
@end ifhtml

@html
<hr />
<p>
@end html
@ifhtml
@uref{./index.html,,Return to the GCC Installation page}

@insertcopying
@end ifhtml
@end ifset

@c ***Prerequisites**************************************************
@ifnothtml
@comment node-name,     next,          previous, up
@node    Prerequisites, Downloading the source, , Installing GCC
@end ifnothtml
@ifset prerequisiteshtml
@ifnothtml
@chapter Prerequisites
@end ifnothtml
@cindex Prerequisites

GCC requires that various tools and packages be available for use in the
build procedure.  Modifying GCC sources requires additional tools
described below.

@heading Tools/packages necessary for building GCC
@table @asis
@item ISO C90 compiler
Necessary to bootstrap the GCC package, although versions of GCC prior
to 3.4 also allow bootstrapping with a traditional (K&R) C compiler.

To make 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 2.95 or later) because source code for language
frontends other than C might use GCC extensions.

@item GNAT

In order to build the Ada compiler (GNAT) you must already have GNAT
installed because portions of the Ada frontend are written in Ada (with
GNAT extensions.)  Refer to the Ada installation instructions for more
specific information.

@item A ``working'' POSIX compatible shell, or GNU bash

Necessary when running @command{configure} because some
@command{/bin/sh} shells have bugs and may crash when configuring the
target libraries.  In other cases, @command{/bin/sh} or even some
@command{ksh} have disastrous corner-case performance problems.  This
can cause target @command{configure} runs to literally take days to
complete in some cases.

So on some platforms @command{/bin/ksh} is sufficient, on others it
isn't.  See the host/target specific instructions for your platform, or
use @command{bash} to be sure.  Then set @env{CONFIG_SHELL} in your
environment to your ``good'' shell prior to running
@command{configure}/@command{make}.

@command{zsh} is not a fully compliant POSIX shell and will not 
work when configuring GCC.

@item GNU binutils

Necessary in some circumstances, optional in others.  See the
host/target specific instructions for your platform for the exact
requirements.

@item gzip version 1.2.4 (or later) or
@itemx bzip2 version 1.0.2 (or later)

Necessary to uncompress GCC @command{tar} files when source code is
obtained via FTP mirror sites.

@item GNU make version 3.79.1 (or later)

You must have GNU make installed to build GCC.

@item GNU tar version 1.12 (or later)

Necessary (only on some platforms) to untar the source code.  Many
systems' @command{tar} programs will also work, only try GNU
@command{tar} if you have problems.

@end table


@heading Tools/packages necessary for modifying GCC
@table @asis

@item autoconf versions 2.13 and 2.57
@itemx GNU m4 version 1.4 (or later)

Necessary when modifying @file{configure.in}, @file{aclocal.m4}, etc.@:
to regenerate @file{configure} and @file{config.in} files.  Most
directories require autoconf 2.13 (exactly), but @file{libiberty},
@file{fastjar}, and @file{libstdc++-v3} require autoconf 2.57 (exactly).

@item automake versions 1.4-p? and 1.7.?

Necessary when modifying a @file{Makefile.am} file to regenerate its
associated @file{Makefile.in}.  Most directories require a 1.4 series
automake; @file{libstdc++-v3} and @file{fastjar} requires a 1.7 series
automake.

@item gettext version 0.12 (or later)

Needed to regenerate @file{gcc.pot}.

@item gperf version 2.7.2 (or later)

Necessary when modifying @command{gperf} input files, e.g.@:
@file{gcc/cp/cfns.gperf} to regenerate its associated header file, e.g.@:
@file{gcc/cp/cfns.h}.

@item expect version ???
@itemx tcl version ???
@itemx dejagnu version ???

Necessary to run the GCC testsuite.

@item autogen version 5.5.4 (or later) and
@itemx guile version 1.4.1 (or later)

Necessary to regenerate @file{fixinc/fixincl.x} from
@file{fixinc/inclhack.def} and @file{fixinc/*.tpl}.

Necessary to run the @file{fixinc} @command{make check}.

Necessary to regenerate the top level @file{Makefile.am} files from
@file{Makefile.tpl} and @file{Makefile.def}.

@item GNU Bison version 1.28 (or later)
Berkeley @command{yacc} (@command{byacc}) is also reported to work other
than for java.

Necessary when modifying @file{*.y} files.

Necessary to build GCC during development because the generated output
files are not included in the CVS repository.  They are included in
releases.

@item Flex version 2.5.4 (or later)

Necessary when modifying @file{*.l} files.

Necessary to build GCC during development because the generated output
files are not included in the CVS repository.  They are included in
releases.

@item Texinfo version 4.2 (or later)

Necessary for running @command{makeinfo} when modifying @file{*.texi}
files to test your changes.

Necessary to build GCC documentation during development because the
generated output files are not included in the CVS repository.  They are
included in releases.

@item @TeX{} (any working version)

Necessary for running @command{texi2dvi}, used when running
@command{make dvi} to create DVI files.

@item cvs version 1.10 (or later)
@itemx ssh (any version)

Necessary to access the CVS repository.  Public releases and weekly
snapshots of the development sources are also available via FTP.

@item perl version 5.6.1 (or later)

Necessary when regenerating @file{Makefile} dependencies in libiberty.
Necessary when regenerating @file{libiberty/functions.texi}.
Necessary when generating manpages from Texinfo manuals.
Used by various scripts to generate some files included in CVS (mainly
Unicode-related and rarely changing) from source tables.

@item GNU diffutils version 2.7 (or later)

Necessary when creating changes to GCC source code to submit for review.

@item patch version 2.5.4 (or later)

Necessary when applying patches, created with @command{diff}, to one's
own sources.

@end table

@html
<hr />
<p>
@end html
@ifhtml
@uref{./index.html,,Return to the GCC Installation page}
@end ifhtml
@end ifset

@c ***Downloading the source**************************************************
@ifnothtml
@comment node-name,     next,          previous, up
@node    Downloading the source, Configuration, Prerequisites, Installing GCC
@end ifnothtml
@ifset downloadhtml
@ifnothtml
@chapter Downloading GCC
@end ifnothtml
@cindex Downloading GCC
@cindex Downloading the Source

GCC is distributed via @uref{http://gcc.gnu.org/cvs.html,,CVS} and FTP
tarballs compressed with @command{gzip} or
@command{bzip2}.  It is possible to download a full distribution or specific
components.

Please refer to our @uref{http://gcc.gnu.org/releases.html,,releases web page}
for information on how to obtain GCC@.

The full distribution includes the C, C++, Objective-C, Fortran, Java,
and Ada (in case of GCC 3.1 and later) compilers.  The full distribution
also includes runtime libraries for C++, Objective-C, Fortran, and Java.
In GCC 3.0 and later versions, GNU compiler testsuites are also included
in the full distribution.

If you choose to download specific components, you must download the core
GCC distribution plus any language specific distributions you wish to
use.  The core distribution includes the C language front end as well as the
shared components.  Each language has a tarball which includes the language
front end as well as the language runtime (when appropriate).

Unpack the core distribution as well as any language specific
distributions in the same directory.

If you also intend to build binutils (either to upgrade an existing
installation or for use in place of the corresponding tools of your
OS), unpack the binutils distribution either in the same directory or
a separate one.  In the latter case, add symbolic links to any
components of the binutils you intend to build alongside the compiler
(@file{bfd}, @file{binutils}, @file{gas}, @file{gprof}, @file{ld},
@file{opcodes}, @dots{}) to the directory containing the GCC sources.

@html
<hr />
<p>
@end html
@ifhtml
@uref{./index.html,,Return to the GCC Installation page}
@end ifhtml
@end ifset

@c ***Configuration***********************************************************
@ifnothtml
@comment node-name,     next,          previous, up
@node    Configuration, Building, Downloading the source, Installing GCC
@end ifnothtml
@ifset configurehtml
@ifnothtml
@chapter Installing GCC: Configuration
@end ifnothtml
@cindex Configuration
@cindex Installing GCC: Configuration

Like most GNU software, GCC must be configured before it can be built.
This document describes the recommended configuration procedure
for both native and cross targets.

We use @var{srcdir} to refer to the toplevel source directory for
GCC; we use @var{objdir} to refer to the toplevel build/object directory.

If you obtained the sources via CVS, @var{srcdir} must refer to the top
@file{gcc} directory, the one where the @file{MAINTAINERS} can be found,
and not its @file{gcc} subdirectory, otherwise the build will fail.

If either @var{srcdir} or @var{objdir} is located on an automounted NFS
file system, the shell's built-in @command{pwd} command will return
temporary pathnames.  Using these can lead to various sorts of build
problems.  To avoid this issue, set the @env{PWDCMD} environment
variable to an automounter-aware @command{pwd} command, e.g.,
@command{pawd} or @samp{amq -w}, during the configuration and build
phases.

First, we @strong{highly} recommend that GCC be built into a
separate directory than the sources which does @strong{not} reside
within the source tree.  This is how we generally build GCC; building
where @var{srcdir} == @var{objdir} should still work, but doesn't
get extensive testing; building where @var{objdir} is a subdirectory
of @var{srcdir} is unsupported.

If you have previously built GCC in the same directory for a
different target machine, do @samp{make distclean} to delete all files
that might be invalid.  One of the files this deletes is @file{Makefile};
if @samp{make distclean} complains that @file{Makefile} does not exist
or issues a message like ``don't know how to make distclean'' it probably
means that the directory is already suitably clean.  However, with the
recommended method of building in a separate @var{objdir}, you should
simply use a different @var{objdir} for each target.

Second, when configuring a native system, either @command{cc} or
@command{gcc} must be in your path or you must set @env{CC} in
your environment before running configure.  Otherwise the configuration
scripts may fail.

Note that the bootstrap compiler and the resulting GCC must be link
compatible, else the bootstrap will fail with linker errors about
incompatible object file formats.  Several multilibed targets are
affected by this requirement, see
@ifnothtml
@ref{Specific, host/target specific installation notes}.
@end ifnothtml
@ifhtml
@uref{specific.html,,host/target specific installation notes}.
@end ifhtml

To configure GCC:

@example
   % mkdir @var{objdir}
   % cd @var{objdir}
   % @var{srcdir}/configure [@var{options}] [@var{target}]
@end example


@heading Target specification
@itemize @bullet
@item
GCC has code to correctly determine the correct value for @var{target}
for nearly all native systems.  Therefore, we highly recommend you not
provide a configure target when configuring a native compiler.

@item
@var{target} must be specified as @option{--target=@var{target}}
when configuring a cross compiler; examples of valid targets would be
i960-rtems, m68k-coff, sh-elf, etc.

@item
Specifying just @var{target} instead of @option{--target=@var{target}}
implies that the host defaults to @var{target}.
@end itemize


@heading Options specification

Use @var{options} to override several configure time options for
GCC@.  A list of supported @var{options} follows; @samp{configure
--help} may list other options, but those not listed below may not
work and should not normally be used.

@table @code
@item --prefix=@var{dirname}
Specify the toplevel installation
directory.  This is the recommended way to install the tools into a directory
other than the default.  The toplevel installation directory defaults to
@file{/usr/local}.

We @strong{highly} recommend against @var{dirname} being the same or a
subdirectory of @var{objdir} or vice versa.  If specifying a directory
beneath a user's home directory tree, some shells will not expand
@var{dirname} correctly if it contains the @samp{~} metacharacter; use
@env{$HOME} instead.

The following standard @command{autoconf} options are supported.  Normally you
should not need to use these options.
@table @code
@item --exec-prefix=@var{dirname}
Specify the toplevel installation directory for architecture-dependent
files.  The default is @file{@var{prefix}}.

@item --bindir=@var{dirname}
Specify the installation directory for the executables called by users
(such as @command{gcc} and @command{g++}).  The default is
@file{@var{exec-prefix}/bin}.

@item --libdir=@var{dirname}
Specify the installation directory for object code libraries and
internal data files of GCC@.  The default is @file{@var{exec-prefix}/lib}.

@item --libexecdir=@var{dirname}
Specify the installation directory for internal executables of GCC@.
  The default is @file{@var{exec-prefix}/libexec}.

@item --with-slibdir=@var{dirname}
Specify the installation directory for the shared libgcc library.  The
default is @file{@var{libdir}}.

@item --infodir=@var{dirname}
Specify the installation directory for documentation in info format.
The default is @file{@var{prefix}/info}.

@item --datadir=@var{dirname}
Specify the installation directory for some architecture-independent
data files referenced by GCC@.  The default is @file{@var{prefix}/share}.

@item --mandir=@var{dirname}
Specify the installation directory for manual pages.  The default is
@file{@var{prefix}/man}.  (Note that the manual pages are only extracts from
the full GCC manuals, which are provided in Texinfo format.  The manpages
are derived by an automatic conversion process from parts of the full
manual.)

@item --with-gxx-include-dir=@var{dirname}
Specify
the installation directory for G++ header files.  The default is
@file{@var{prefix}/include/g++-v3}.

@end table

@item --program-prefix=@var{prefix}
GCC supports some transformations of the names of its programs when
installing them. This option prepends @var{prefix} to the names of
programs to install in @var{bindir} (see above). For example, specifying
@option{--program-prefix=foo-} would result in @samp{gcc}
being installed as @file{/usr/local/bin/foo-gcc}.

@item --program-suffix=@var{suffix}
Appends @var{suffix} to the names of programs to install in @var{bindir}
(see above). For example, specifying @option{--program-suffix=-3.1}
would result in @samp{gcc} being installed as
@file{/usr/local/bin/gcc-3.1}.

@item --program-transform-name=@var{pattern}
Applies the @samp{sed} script @var{pattern} to be applied to the names
of programs to install in @var{bindir} (see above). @var{pattern} has to
consist of one or more basic @samp{sed} editing commands, separated by
semicolons. For example, if you want the @samp{gcc} program name to be
transformed to the installed program @file{/usr/local/bin/myowngcc} and
the @samp{g++} program name to be transformed to
@file{/usr/local/bin/gspecial++} without changing other program names,
you could use the pattern
@option{--program-transform-name='s/^gcc$/myowngcc/; s/^g++$/gspecial++/'}
to achieve this effect.

All three options can be combined and used together, resulting in more
complex conversion patterns. As a basic rule, @var{prefix} (and
@var{suffix}) are prepended (appended) before further transformations
can happen with a special transformation script @var{pattern}.

As currently implemented, this option only takes effect for native
builds; cross compiler binaries' names are not transformed even when a
transformation is explicitly asked for by one of these options.

For native builds, some of the installed programs are also installed
with the target alias in front of their name, as in
@samp{i686-pc-linux-gnu-gcc}. All of the above transformations happen
before the target alias is prepended to the name - so, specifying
@option{--program-prefix=foo-} and @option{program-suffix=-3.1}, the
resulting binary would be installed as
@file{/usr/local/bin/i686-pc-linux-gnu-foo-gcc-3.1}.

As a last shortcoming, none of the installed Ada programs are
transformed yet, which will be fixed in some time.

@item --with-local-prefix=@var{dirname}
Specify the
installation directory for local include files.  The default is
@file{/usr/local}.  Specify this option if you want the compiler to
search directory @file{@var{dirname}/include} for locally installed
header files @emph{instead} of @file{/usr/local/include}.

You should specify @option{--with-local-prefix} @strong{only} if your
site has a different convention (not @file{/usr/local}) for where to put
site-specific files.

The default value for @option{--with-local-prefix} is @file{/usr/local}
regardless of the value of @option{--prefix}.  Specifying
@option{--prefix} has no effect on which directory GCC searches for
local header files.  This may seem counterintuitive, but actually it is
logical.

The purpose of @option{--prefix} is to specify where to @emph{install
GCC}.  The local header files in @file{/usr/local/include}---if you put
any in that directory---are not part of GCC@.  They are part of other
programs---perhaps many others.  (GCC installs its own header files in
another directory which is based on the @option{--prefix} value.)

Both the local-prefix include directory and the GCC-prefix include
directory are part of GCC's "system include" directories.  Although these
two directories are not fixed, they need to be searched in the proper
order for the correct processing of the include_next directive.  The
local-prefix include directory is searched before the GCC-prefix
include directory.  Another characteristic of system include directories
is that pedantic warnings are turned off for headers in these directories.

Some autoconf macros add @option{-I @var{directory}} options to the
compiler command line, to ensure that directories containing installed
packages' headers are searched.  When @var{directory} is one of GCC's
system include directories, GCC will ignore the option so that system
directories continue to be processed in the correct order.  This
may result in a search order different from what was specified but the
directory will still be searched.

GCC automatically searches for ordinary libraries using
@env{GCC_EXEC_PREFIX}.  Thus, when the same installation prefix is
used for both GCC and packages, GCC will automatically search for
both headers and libraries.  This provides a configuration that is
easy to use.  GCC behaves in a manner similar to that when it is
installed as a system compiler in @file{/usr}.

Sites that need to install multiple versions of GCC may not want to
use the above simple configuration.  It is possible to use the
@option{--program-prefix}, @option{--program-suffix} and
@option{--program-transform-name} options to install multiple versions
into a single directory, but it may be simpler to use different prefixes
and the @option{--with-local-prefix} option to specify the location of the
site-specific files for each version.  It will then be necessary for
users to specify explicitly the location of local site libraries
(e.g., with @env{LIBRARY_PATH}).

The same value can be used for both @option{--with-local-prefix} and
@option{--prefix} provided it is not @file{/usr}.  This can be used
to avoid the default search of @file{/usr/local/include}.

@strong{Do not} specify @file{/usr} as the @option{--with-local-prefix}!
The directory you use for @option{--with-local-prefix} @strong{must not}
contain any of the system's standard header files.  If it did contain
them, certain programs would be miscompiled (including GNU Emacs, on
certain targets), because this would override and nullify the header
file corrections made by the @command{fixincludes} script.

Indications are that people who use this option use it based on mistaken
ideas of what it is for.  People use it as if it specified where to
install part of GCC@.  Perhaps they make this assumption because
installing GCC creates the directory.

@item --enable-shared[=@var{package}[,@dots{}]]
Build shared versions of libraries, if shared libraries are supported on
the target platform.  Unlike GCC 2.95.x and earlier, shared libraries
are enabled by default on all platforms that support shared libraries,
except for @samp{libobjc} which is built as a static library only by
default.

If a list of packages is given as an argument, build shared libraries
only for the listed packages.  For other packages, only static libraries
will be built.  Package names currently recognized in the GCC tree are
@samp{libgcc} (also known as @samp{gcc}), @samp{libstdc++} (not
@samp{libstdc++-v3}), @samp{libffi}, @samp{zlib}, @samp{boehm-gc} and
@samp{libjava}.  Note that @samp{libobjc} does not recognize itself by
any name, so, if you list package names in @option{--enable-shared},
you will only get static Objective-C libraries.  @samp{libf2c} and
@samp{libiberty} do not support shared libraries at all.

Use @option{--disable-shared} to build only static libraries.  Note that
@option{--disable-shared} does not accept a list of package names as
argument, only @option{--enable-shared} does.

@item @anchor{with-gnu-as}--with-gnu-as
Specify that the compiler should assume that the
assembler it finds is the GNU assembler.  However, this does not modify
the rules to find an assembler and will result in confusion if the
assembler found is not actually the GNU assembler.  (Confusion may also
result if the compiler finds the GNU assembler but has not been
configured with @option{--with-gnu-as}.)  If you have more than one
assembler installed on your system, you may want to use this option in
connection with @option{--with-as=@var{pathname}}.

The following systems are the only ones where it makes a difference
whether you use the GNU assembler.  On any other system,
@option{--with-gnu-as} has no effect.

@itemize @bullet
@item @samp{hppa1.0-@var{any}-@var{any}}
@item @samp{hppa1.1-@var{any}-@var{any}}
@item @samp{i386-@var{any}-sysv}
@item @samp{m68k-bull-sysv}
@item @samp{m68k-hp-hpux}
@item @samp{m68000-hp-hpux}
@item @samp{m68000-att-sysv}
@item @samp{@var{any}-lynx-lynxos}
@item @samp{mips-@var{any}}
@item @samp{sparc-sun-solaris2.@var{any}}
@item @samp{sparc64-@var{any}-solaris2.@var{any}}
@end itemize

On the systems listed above (except for the HP-PA, the SPARC, for ISC on
the 386, and for @samp{mips-sgi-irix5.*}), if you use the GNU assembler,
you should also use the GNU linker (and specify @option{--with-gnu-ld}).

@item @anchor{with-as}--with-as=@var{pathname}
Specify that the
compiler should use the assembler pointed to by @var{pathname}, rather
than the one found by the standard rules to find an assembler, which
are:
@itemize @bullet
@item
Check the @file{@var{libexec}/gcc/@var{target}/@var{version}}
directory, where @var{libexec} defaults to
@file{@var{exec-prefix}/libexec} and @var{exec-prefix} defaults to
@var{prefix} which defaults to @file{/usr/local} unless overridden by
the @option{--prefix=@var{pathname}} switch described
above. @var{target} is the target system triple, such as
@samp{sparc-sun-solaris2.7}, and @var{version} denotes the GCC
version, such as 3.0.
@item
Check operating system specific directories (e.g.@: @file{/usr/ccs/bin} on
Sun Solaris 2).
@end itemize
Note that these rules do not check for the value of @env{PATH}.  You may
want to use @option{--with-as} if no assembler is installed in the
directories listed above, or if you have multiple assemblers installed
and want to choose one that is not found by the above rules.

@item @anchor{with-gnu-ld}--with-gnu-ld
Same as @uref{#with-gnu-as,,@option{--with-gnu-as}}
but for the linker.

@item --with-ld=@var{pathname}
Same as @uref{#with-as,,@option{--with-as}}
but for the linker.

@item --with-stabs
Specify that stabs debugging
information should be used instead of whatever format the host normally
uses.  Normally GCC uses the same debug format as the host system.

On MIPS based systems and on Alphas, you must specify whether you want
GCC to create the normal ECOFF debugging format, or to use BSD-style
stabs passed through the ECOFF symbol table.  The normal ECOFF debug
format cannot fully handle languages other than C@.  BSD stabs format can
handle other languages, but it only works with the GNU debugger GDB@.

Normally, GCC uses the ECOFF debugging format by default; if you
prefer BSD stabs, specify @option{--with-stabs} when you configure GCC@.

No matter which default you choose when you configure GCC, the user
can use the @option{-gcoff} and @option{-gstabs+} options to specify explicitly
the debug format for a particular compilation.

@option{--with-stabs} is meaningful on the ISC system on the 386, also, if
@option{--with-gas} is used.  It selects use of stabs debugging
information embedded in COFF output.  This kind of debugging information
supports C++ well; ordinary COFF debugging information does not.

@option{--with-stabs} is also meaningful on 386 systems running SVR4.  It
selects use of stabs debugging information embedded in ELF output.  The
C++ compiler currently (2.6.0) does not support the DWARF debugging
information normally used on 386 SVR4 platforms; stabs provide a
workable alternative.  This requires gas and gdb, as the normal SVR4
tools can not generate or interpret stabs.

@item --disable-multilib
Specify that multiple target
libraries to support different target variants, calling
conventions, etc should not be built.  The default is to build a
predefined set of them.

Some targets provide finer-grained control over which multilibs are built
(e.g., @option{--disable-softfloat}):
@table @code
@item arc-*-elf*
biendian.

@item arm-*-*
fpu, 26bit, underscore, interwork, biendian, nofmult.

@item m68*-*-*
softfloat, m68881, m68000, m68020.

@item mips*-*-*
single-float, biendian, softfloat.

@item powerpc*-*-*, rs6000*-*-*
aix64, pthread, softfloat, powercpu, powerpccpu, powerpcos, biendian,
sysv, aix.

@end table

@item --enable-threads
Specify that the target
supports threads.  This affects the Objective-C compiler and runtime
library, and exception handling for other languages like C++ and Java.
On some systems, this is the default.

In general, the best (and, in many cases, the only known) threading
model available will be configured for use.  Beware that on some
systems, gcc has not been taught what threading models are generally
available for the system.  In this case, @option{--enable-threads} is an
alias for @option{--enable-threads=single}.

@item --disable-threads
Specify that threading support should be disabled for the system.
This is an alias for @option{--enable-threads=single}.

@item --enable-threads=@var{lib}
Specify that
@var{lib} is the thread support library.  This affects the Objective-C
compiler and runtime library, and exception handling for other languages
like C++ and Java.  The possibilities for @var{lib} are:

@table @code
@item aix
AIX thread support.
@item dce
DCE thread support.
@item gnat
Ada tasking support.  For non-Ada programs, this setting is equivalent
to @samp{single}. When used in conjunction with the Ada run time, it
causes GCC to use the same thread primitives as Ada uses.  This option
is necessary when using both Ada and the back end exception handling,
which is the default for most Ada targets.
@item mach
Generic MACH thread support, known to work on NeXTSTEP@.  (Please note
that the file needed to support this configuration, @file{gthr-mach.h}, is
missing and thus this setting will cause a known bootstrap failure.)
@item no
This is an alias for @samp{single}.
@item posix
Generic POSIX thread support.
@item rtems
RTEMS thread support.
@item single
Disable thread support, should work for all platforms.
@item solaris
Sun Solaris 2 thread support.
@item vxworks
VxWorks thread support.
@item win32
Microsoft Win32 API thread support.
@end table

@item --with-cpu=@var{cpu}
Specify which cpu variant the compiler should generate code for by default.
@var{cpu} will be used as the default value of the @option{-mcpu=} switch.
This option is only supported on some targets, including ARM, i386, PowerPC,
and SPARC@.

@item --with-schedule=@var{cpu}
@itemx --with-arch=@var{cpu}
@itemx --with-tune=@var{cpu}
@itemx --with-abi=@var{abi}
@itemx --with-float=@var{type}
These configure options provide default values for the @option{-mschedule=},
@option{-march=}, @option{-mtune=}, and @option{-mabi=} options and for
@option{-mhard-float} or @option{-msoft-float}.  As with @option{--with-cpu},
which switches will be accepted and acceptable values of the arguments depend
on the target.

@item --enable-altivec
Specify that the target supports AltiVec vector enhancements.  This
option will adjust the ABI for AltiVec enhancements, as well as generate
AltiVec code when appropriate.  This option is only available for
PowerPC systems.

@item --enable-target-optspace
Specify that target
libraries should be optimized for code space instead of code speed.
This is the default for the m32r platform.

@item --disable-cpp
Specify that a user visible @command{cpp} program should not be installed.

@item --with-cpp-install-dir=@var{dirname}
Specify that the user visible @command{cpp} program should be installed
in @file{@var{prefix}/@var{dirname}/cpp}, in addition to @var{bindir}.

@item --enable-initfini-array
Force the use of sections @code{.init_array} and @code{.fini_array}
(instead of @code{.init} and @code{.fini}) for constructors and
destructors.  Option @option{--disable-initfini-array} has the
opposite effect.  If neither option is specified, the configure script
will try to guess whether the @code{.init_array} and
@code{.fini_array} sections are supported and, if they are, use them.

@item --enable-maintainer-mode
The build rules that
regenerate the GCC master message catalog @file{gcc.pot} are normally
disabled.  This is because it can only be rebuilt if the complete source
tree is present.  If you have changed the sources and want to rebuild the
catalog, configuring with @option{--enable-maintainer-mode} will enable
this.  Note that you need a recent version of the @code{gettext} tools
to do so.

@item --enable-generated-files-in-srcdir
Neither the .c and .h files that are generated from bison and flex nor the
info manuals and man pages that are built from the .texi files are present
in the CVS development tree.  When building GCC from that development tree,
or from a snapshot which are created from CVS, then those generated files
are placed in your build directory, which allows for the source to be in a
readonly directory.

If you configure with @option{--enable-generated-files-in-srcdir} then those
generated files will go into the source directory.  This is mainly intended
for generating release or prerelease tarballs of the GCC sources, since it
is not a requirement that the users of source releases to have flex, bison, or
makeinfo.  

@item --enable-version-specific-runtime-libs
Specify
that runtime libraries should be installed in the compiler specific
subdirectory (@file{@var{libdir}/gcc}) rather than the usual places.  In
addition, @samp{libstdc++}'s include files will be installed into
@file{@var{libdir}} unless you overruled it by using
@option{--with-gxx-include-dir=@var{dirname}}.  Using this option is
particularly useful if you intend to use several versions of GCC in
parallel. This is currently supported by @samp{libf2c} and
@samp{libstdc++}, and is the default for @samp{libobjc} which cannot be
changed in this case.

@item --enable-languages=@var{lang1},@var{lang2},@dots{}
Specify that only a particular subset of compilers and
their runtime libraries should be built.  For a list of valid values for
@var{langN} you can issue the following command in the
@file{gcc} directory of your GCC source tree:@*
@example
grep language= */config-lang.in
@end example
Currently, you can use any of the following:
@code{ada}, @code{c}, @code{c++}, @code{f77}, @code{java}, @code{objc}.
Building the Ada compiler has special requirements, see below.@*
If you do not pass this flag, all languages available in the @file{gcc}
sub-tree will be configured.  Re-defining @code{LANGUAGES} when calling
@samp{make bootstrap} @strong{does not} work anymore, as those
language sub-directories might not have been configured!

@item --disable-libgcj
Specify that the run-time libraries
used by GCJ should not be built.  This is useful in case you intend
to use GCJ with some other run-time, or you're going to install it
separately, or it just happens not to build on your particular
machine.  In general, if the Java front end is enabled, the GCJ
libraries will be enabled too, unless they're known to not work on
the target platform.  If GCJ is enabled but @samp{libgcj} isn't built, you
may need to port it; in this case, before modifying the top-level
@file{configure.in} so that @samp{libgcj} is enabled by default on this platform,
you may use @option{--enable-libgcj} to override the default.

@item --with-dwarf2
Specify that the compiler should
use DWARF 2 debugging information as the default.

@item --enable-win32-registry
@itemx --enable-win32-registry=@var{key}
@itemx --disable-win32-registry
The @option{--enable-win32-registry} option enables Windows-hosted GCC
to look up installations paths in the registry using the following key:

@smallexample
@code{HKEY_LOCAL_MACHINE\SOFTWARE\Free Software Foundation\@var{key}}
@end smallexample

@var{key} defaults to GCC version number, and can be overridden by the
@option{--enable-win32-registry=@var{key}} option. Vendors and distributors
who use custom installers are encouraged to provide a different key,
perhaps one comprised of vendor name and GCC version number, to
avoid conflict with existing installations.  This feature is enabled
by default, and can be disabled by @option{--disable-win32-registry}
option.  This option has no effect on the other hosts.

@item --nfp
Specify that the machine does not have a floating point unit.  This
option only applies to @samp{m68k-sun-sunos@var{n}}.  On any other
system, @option{--nfp} has no effect.

@item --enable-werror
@itemx --disable-werror
@itemx --enable-werror=yes
@itemx --enable-werror=no
When you specify this option, it controls whether certain files in the
compiler are built with @option{-Werror} in bootstrap stage2 and later.
If you don't specify it, @option{-Werror} is turned on for the main
development trunk.  However it defaults to off for release branches and
final releases.  The specific files which get @option{-Werror} are
controlled by the Makefiles.

@item --enable-checking
@itemx --enable-checking=@var{list}
When you specify this option, the compiler is built to perform checking
of tree node types when referencing fields of that node, and some other
internal consistency checks.  This does not change the generated code,
but adds error checking within the compiler.  This will slow down the
compiler and may only work properly if you are building the compiler
with GCC@.  This is on by default when building from CVS or snapshots,
but off for releases.  More control over the checks may be had by
specifying @var{list}; the categories of checks available are
@samp{misc}, @samp{tree}, @samp{gc}, @samp{rtl}, @samp{rtlflag},
@samp{fold}, @samp{gcac} and @samp{valgrind}.  The check @samp{valgrind}
requires the external @command{valgrind} simulator, available from
@uref{http://valgrind.kde.org/}.  The default when @var{list} is
not specified is @samp{misc,tree,gc,rtlflag}; the checks @samp{rtl},
@samp{gcac} and @samp{valgrind} are very expensive.

@item --enable-coverage
@item --enable-coverage=@var{level}
With this option, the compiler is built to collect self coverage
information, every time it is run. This is for internal development
purposes, and only works when the compiler is being built with gcc. The
@var{level} argument controls whether the compiler is built optimized or
not, values are @samp{opt} and @samp{noopt}. For coverage analysis you
want to disable optimization, for performance analysis you want to
enable optimization. When coverage is enabled, the default level is
without optimization.

@item --enable-nls
@itemx --disable-nls
The @option{--enable-nls} option enables Native Language Support (NLS),
which lets GCC output diagnostics in languages other than American
English.  Native Language Support is enabled by default if not doing a
canadian cross build.  The @option{--disable-nls} option disables NLS@.

@item --with-included-gettext
If NLS is enabled, the @option{--with-included-gettext} option causes the build
procedure to prefer its copy of GNU @command{gettext}.

@item --with-catgets
If NLS is enabled, and if the host lacks @code{gettext} but has the
inferior @code{catgets} interface, the GCC build procedure normally
ignores @code{catgets} and instead uses GCC's copy of the GNU
@code{gettext} library.  The @option{--with-catgets} option causes the
build procedure to use the host's @code{catgets} in this situation.

@item --with-libiconv-prefix=@var{dir}
Search for libiconv header files in @file{@var{dir}/include} and
libiconv library files in @file{@var{dir}/lib}.

@item --with-system-zlib
Use installed zlib rather than that included with GCC@.  This option
only applies if the Java front end is being built.

@item --enable-obsolete
Enable configuration for an obsoleted system.  If you attempt to
configure GCC for a system (build, host, or target) which has been
obsoleted, and you do not specify this flag, configure will halt with an
error message.

All support for systems which have been obsoleted in one release of GCC
is removed entirely in the next major release, unless someone steps
forward to maintain the port.
@end table

Some options which only apply to building cross compilers:
@table @code
@item --with-sysroot
@itemx --with-sysroot=@var{dir}
Tells GCC to consider @var{dir} as the root of a tree that contains a
(subset of) the root filesystem of the target operating system.
Target system headers, libraries and run-time object files will be
searched in there.  The specified directory is not copied into the
install tree, unlike the options @option{--with-headers} and
@option{--with-libs} that this option obsoletes.  The default value,
in case @option{--with-sysroot} is not given an argument, is
@option{$@{gcc_tooldir@}/sys-root}.  If the specified directory is a
subdirectory of @option{$@{exec_prefix@}}, then it will be found relative to
the GCC binaries if the installation tree is moved.

@item --with-headers
@itemx --with-headers=@var{dir}
Deprecated in favor of @option{--with-sysroot}.
Specifies that target headers are available when building a cross compiler.
The @var{dir} argument specifies a directory which has the target include
files.  These include files will be copied into the @file{gcc} install
directory.  @emph{This option with the @var{dir} argument is required} when
building a cross compiler, if @file{@var{prefix}/@var{target}/sys-include}
doesn't pre-exist.  If @file{@var{prefix}/@var{target}/sys-include} does
pre-exist, the @var{dir} argument may be omitted.  @command{fixincludes}
will be run on these files to make them compatible with GCC.

@item --without-headers
Tells GCC not use any target headers from a libc when building a cross
compiler.  When crossing to GNU/Linux, you need the headers so gcc
can build the exception handling for libgcc.
See @uref{http://www.objsw.com/CrossGCC/,,CrossGCC} for more information
on this option.

@item --with-libs
@itemx --with-libs=``@var{dir1} @var{dir2} @dots{} @var{dirN}''
Deprecated in favor of @option{--with-sysroot}.
Specifies a list of directories which contain the target runtime
libraries.  These libraries will be copied into the @file{gcc} install
directory.  If the directory list is omitted, this option has no
effect.
@item --with-newlib
Specifies that @samp{newlib} is
being used as the target C library.  This causes @code{__eprintf} to be
omitted from @file{libgcc.a} on the assumption that it will be provided by
@samp{newlib}.
@end table

Note that each @option{--enable} option has a corresponding
@option{--disable} option and that each @option{--with} option has a
corresponding @option{--without} option.

@html
<hr />
<p>
@end html
@ifhtml
@uref{./index.html,,Return to the GCC Installation page}
@end ifhtml
@end ifset

@c ***Building****************************************************************
@ifnothtml
@comment node-name,     next,          previous, up
@node    Building, Testing, Configuration, Installing GCC
@end ifnothtml
@ifset buildhtml
@ifnothtml
@chapter Building
@end ifnothtml
@cindex Installing GCC: Building

Now that GCC is configured, you are ready to build the compiler and
runtime libraries.

We @strong{highly} recommend that GCC be built using GNU make; 
other versions may work, then again they might not.
GNU make is required for compiling GNAT (the Ada compiler) and the Java
runtime library.

(For example, many broken versions of make will fail if you use the
recommended setup where @var{objdir} is different from @var{srcdir}.
Other broken versions may recompile parts of the compiler when
installing the compiler.)

Some commands executed when making the compiler may fail (return a
nonzero status) and be ignored by @command{make}.  These failures, which
are often due to files that were not found, are expected, and can safely
be ignored.

It is normal to have compiler warnings when compiling certain files.
Unless you are a GCC developer, you can generally ignore these warnings
unless they cause compilation to fail.  Developers should attempt to fix
any warnings encountered, however they can temporarily continue past
warnings-as-errors by specifying the configure flag
@option{--disable-werror}.

On certain old systems, defining certain environment variables such as
@env{CC} can interfere with the functioning of @command{make}.

If you encounter seemingly strange errors when trying to build the
compiler in a directory other than the source directory, it could be
because you have previously configured the compiler in the source
directory.  Make sure you have done all the necessary preparations.

If you build GCC on a BSD system using a directory stored in an old System
V file system, problems may occur in running @command{fixincludes} if the
System V file system doesn't support symbolic links.  These problems
result in a failure to fix the declaration of @code{size_t} in
@file{sys/types.h}.  If you find that @code{size_t} is a signed type and
that type mismatches occur, this could be the cause.

The solution is not to use such a directory for building GCC@.

When building from CVS or snapshots, or if you modify parser sources,
you need the Bison parser generator installed.  Any version 1.25 or
later should work; older versions may also work.  If you do not modify
parser sources, releases contain the Bison-generated files and you do
not need Bison installed to build them.

When building from CVS or snapshots, or if you modify Texinfo
documentation, you need version 4.2 or later of Texinfo installed if you
want Info documentation to be regenerated.  Releases contain Info
documentation pre-built for the unmodified documentation in the release.

@section Building a native compiler

For a native build issue the command @samp{make bootstrap}.  This
will build the entire GCC system, which includes the following steps:

@itemize @bullet
@item
Build host tools necessary to build the compiler such as texinfo, bison,
gperf.

@item
Build target tools for use by the compiler such as binutils (bfd,
binutils, gas, gprof, ld, and opcodes)
if they have been individually linked
or moved into the top level GCC source tree before configuring.

@item
Perform a 3-stage bootstrap of the compiler.

@item
Perform a comparison test of the stage2 and stage3 compilers.

@item
Build runtime libraries using the stage3 compiler from the previous step.

@end itemize

If you are short on disk space you might consider @samp{make
bootstrap-lean} instead.  This is identical to @samp{make
bootstrap} except that object files from the stage1 and
stage2 of the 3-stage bootstrap of the compiler are deleted as
soon as they are no longer needed.

If you want to save additional space during the bootstrap and in
the final installation as well, you can build the compiler binaries
without debugging information as in the following example.  This will save
roughly 40% of disk space both for the bootstrap and the final installation.
(Libraries will still contain debugging information.)

@example
     make CFLAGS='-O' LIBCFLAGS='-g -O2' \
       LIBCXXFLAGS='-g -O2 -fno-implicit-templates' bootstrap
@end example

If you wish to use non-default GCC flags when compiling the stage2 and
stage3 compilers, set @code{BOOT_CFLAGS} on the command line when doing
@samp{make bootstrap}.  Non-default optimization flags are less well
tested here than the default of @samp{-g -O2}, but should still work.
In a few cases, you may find that you need to specify special flags such
as @option{-msoft-float} here to complete the bootstrap; or, if the
native compiler miscompiles the stage1 compiler, you may need to work
around this, by choosing @code{BOOT_CFLAGS} to avoid the parts of the
stage1 compiler that were miscompiled, or by using @samp{make
bootstrap4} to increase the number of stages of bootstrap.

If you used the flag @option{--enable-languages=@dots{}} to restrict
the compilers to be built, only those you've actually enabled will be
built.  This will of course only build those runtime libraries, for
which the particular compiler has been built.  Please note,
that re-defining @env{LANGUAGES} when calling @samp{make bootstrap}
@strong{does not} work anymore!

If the comparison of stage2 and stage3 fails, this normally indicates
that the stage2 compiler has compiled GCC incorrectly, and is therefore
a potentially serious bug which you should investigate and report.  (On
a few systems, meaningful comparison of object files is impossible; they
always appear ``different''.  If you encounter this problem, you will
need to disable comparison in the @file{Makefile}.)

@section Building a cross compiler

We recommend reading the
@uref{http://www.objsw.com/CrossGCC/,,crossgcc FAQ}
for information about building cross compilers.

When building a cross compiler, it is not generally possible to do a
3-stage bootstrap of the compiler.  This makes for an interesting problem
as parts of GCC can only be built with GCC@.

To build a cross compiler, we first recommend building and installing a
native compiler.  You can then use the native GCC compiler to build the
cross compiler.  The installed native compiler needs to be GCC version
2.95 or later.

Assuming you have already installed a native copy of GCC and configured
your cross compiler, issue the command @command{make}, which performs the
following steps:

@itemize @bullet
@item
Build host tools necessary to build the compiler such as texinfo, bison,
gperf.

@item
Build target tools for use by the compiler such as binutils (bfd,
binutils, gas, gprof, ld, and opcodes)
if they have been individually linked or moved into the top level GCC source
tree before configuring.

@item
Build the compiler (single stage only).

@item
Build runtime libraries using the compiler from the previous step.
@end itemize

Note that if an error occurs in any step the make process will exit.

If you are not building GNU binutils in the same source tree as GCC,
you will need a cross-assembler and cross-linker installed before
configuring GCC@.  Put them in the directory
@file{@var{prefix}/@var{target}/bin}.  Here is a table of the tools
you should put in this directory:

@table @file
@item as
This should be the cross-assembler.

@item ld
This should be the cross-linker.

@item ar
This should be the cross-archiver: a program which can manipulate
archive files (linker libraries) in the target machine's format.

@item ranlib
This should be a program to construct a symbol table in an archive file.
@end table

The installation of GCC will find these programs in that directory,
and copy or link them to the proper place to for the cross-compiler to
find them when run later.

The easiest way to provide these files is to build the Binutils package.
Configure it with the same @option{--host} and @option{--target}
options that you use for configuring GCC, then build and install
them.  They install their executables automatically into the proper
directory.  Alas, they do not support all the targets that GCC
supports.

If you are not building a C library in the same source tree as GCC,
you should also provide the target libraries and headers before
configuring GCC, specifying the directories with
@option{--with-sysroot} or @option{--with-headers} and
@option{--with-libs}.  Many targets also require ``start files'' such
as @file{crt0.o} and
@file{crtn.o} which are linked into each executable.  There may be several
alternatives for @file{crt0.o}, for use with profiling or other
compilation options.  Check your target's definition of
@code{STARTFILE_SPEC} to find out what start files it uses.

@section Building in parallel

You can use @samp{make bootstrap MAKE="make -j 2" -j 2}, or just
@samp{make -j 2 bootstrap} for GNU Make 3.79 and above, instead of
@samp{make bootstrap} to build GCC in parallel.
You can also specify a bigger number, and in most cases using a value
greater than the number of processors in your machine will result in
fewer and shorter I/O latency hits, thus improving overall throughput;
this is especially true for slow drives and network filesystems.

@section Building the Ada compiler

In order to build GNAT, the Ada compiler, you need a working GNAT
compiler (GNAT version 3.14 or later, or GCC version 3.1 or later),
including GNAT tools such as @command{gnatmake} and @command{gnatlink},
since the Ada front end is written in Ada (with some
GNAT-specific extensions), and GNU make.

@command{configure} does not test whether the GNAT installation works
and has a sufficiently recent version; if too old a GNAT version is
installed, the build will fail unless @option{--enable-languages} is
used to disable building the Ada front end.

At the moment, the GNAT library and several tools for GNAT are not built
by @samp{make bootstrap}.  For a native build, you have to invoke
@samp{make gnatlib_and_tools} in the @file{@var{objdir}/gcc}
subdirectory before proceeding with the next steps.
For a cross build, you need to invoke
@samp{make gnatlib cross-gnattools ada.all.cross}.  For a canadian
cross you only need to invoke @samp{make cross-gnattools}; the GNAT
library would be the same as the one built for the cross compiler.

For example, you can build a native Ada compiler by issuing the
following commands (assuming @command{make} is GNU make):

@example
    cd @var{objdir}
    @var{srcdir}/configure --enable-languages=c,ada
    cd @var{objdir}
    make bootstrap
    cd gcc
    make gnatlib_and_tools
    cd ..
@end example

Currently, when compiling the Ada front end, you cannot use the parallel
build feature described in the previous section.

@section Building with profile feedback

It is possible to use profile feedback to optimize the compiler itself.  This
should result in a faster compiler binary.  Experiments done on x86 using gcc
3.3 showed approximately 7 percent speedup on compiling C programs.  To
bootstrap compiler with profile feedback, use @code{make profiledbootstrap}.

When @samp{make profiledbootstrap} is run, it will first build a @code{stage1}
compiler.  This compiler is used to build a @code{stageprofile} compiler
instrumented to collect execution counts of instruction and branch
probabilities.  Then runtime libraries are compiled with profile collected.
Finally a @code{stagefeedback} compiler is built using the information collected.

Unlike @samp{make bootstrap} several additional restrictions apply.  The
compiler used to build @code{stage1} needs to support a 64-bit integral type.
It is recommended to only use GCC for this.  Also parallel make is currently
not supported since collisions in profile collecting may occur.

@html
<hr />
<p>
@end html
@ifhtml
@uref{./index.html,,Return to the GCC Installation page}
@end ifhtml
@end ifset

@c ***Testing*****************************************************************
@ifnothtml
@comment node-name,     next,          previous, up
@node    Testing, Final install, Building, Installing GCC
@end ifnothtml
@ifset testhtml
@ifnothtml
@chapter Installing GCC: Testing
@end ifnothtml
@cindex Testing
@cindex Installing GCC: Testing
@cindex Testsuite

Before you install GCC, we encourage you to run the testsuites and to
compare your results with results from a similar configuration that have
been submitted to the
@uref{http://gcc.gnu.org/ml/gcc-testresults/,,gcc-testresults mailing list}.
Some of these archived results are linked from the build status lists
at @uref{http://gcc.gnu.org/buildstat.html}, although not everyone who
reports a successful build runs the testsuites and submits the results.
This step is optional and may require you to download additional software,
but it can give you confidence in your new GCC installation or point out
problems before you install and start using your new GCC.

First, you must have @uref{download.html,,downloaded the testsuites}.
These are part of the full distribution, but if you downloaded the
``core'' compiler plus any front ends, you must download the testsuites
separately.

Second, you must have the testing tools installed.  This includes
@uref{http://www.gnu.org/software/dejagnu/,,DejaGnu} 1.4.1 or 1.4.3
and later, Tcl, and Expect; the DejaGnu site has links to these.

If the directories where @command{runtest} and @command{expect} were
installed are not in the @env{PATH}, you may need to set the following
environment variables appropriately, as in the following example (which
assumes that DejaGnu has been installed under @file{/usr/local}):

@example
     TCL_LIBRARY = /usr/local/share/tcl8.0
     DEJAGNULIBS = /usr/local/share/dejagnu
@end example

(On systems such as Cygwin, these paths are required to be actual
paths, not mounts or links; presumably this is due to some lack of
portability in the DejaGnu code.)


Finally, you can run the testsuite (which may take a long time):
@example
     cd @var{objdir}; make -k check
@end example

This will test various components of GCC, such as compiler
front ends and runtime libraries.  While running the testsuite, DejaGnu
might emit some harmless messages resembling
@samp{WARNING: Couldn't find the global config file.} or 
@samp{WARNING: Couldn't find tool init file} that can be ignored.

@section How can I run the test suite on selected tests?

In order to run sets of tests selectively, there are targets
@samp{make check-gcc} and @samp{make check-g++}
in the @file{gcc} subdirectory of the object directory.  You can also
just run @samp{make check} in a subdirectory of the object directory.


A more selective way to just run all @command{gcc} execute tests in the
testsuite is to use

@example
    make check-gcc RUNTESTFLAGS="execute.exp @var{other-options}"
@end example

Likewise, in order to run only the @command{g++} ``old-deja'' tests in
the testsuite with filenames matching @samp{9805*}, you would use

@example
    make check-g++ RUNTESTFLAGS="old-deja.exp=9805* @var{other-options}"
@end example

The @file{*.exp} files are located in the testsuite directories of the GCC
source, the most important ones being @file{compile.exp},
@file{execute.exp}, @file{dg.exp} and @file{old-deja.exp}.
To get a list of the possible @file{*.exp} files, pipe the
output of @samp{make check} into a file and look at the
@samp{Running @dots{}  .exp} lines.

@section Passing options and running multiple testsuites

You can pass multiple options to the testsuite using the
@samp{--target_board} option of DejaGNU, either passed as part of
@samp{RUNTESTFLAGS}, or directly to @command{runtest} if you prefer to
work outside the makefiles.  For example,

@example
    make check-g++ RUNTESTFLAGS="--target_board=unix/-O3/-fno-strength-reduce"
@end example

will run the standard @command{g++} testsuites (``unix'' is the target name
for a standard native testsuite situation), passing
@samp{-O3 -fno-strength-reduce} to the compiler on every test, i.e.,
slashes separate options.

You can run the testsuites multiple times using combinations of options
with a syntax similar to the brace expansion of popular shells:

@example
    @dots{}"--target_board=arm-sim@{-mhard-float,-msoft-float@}@{-O1,-O2,-O3,@}"
@end example

(Note the empty option caused by the trailing comma in the final group.)
The following will run each testsuite eight times using the @samp{arm-sim}
target, as if you had specified all possible combinations yourself:

@example
    --target_board=arm-sim/-mhard-float/-O1
    --target_board=arm-sim/-mhard-float/-O2
    --target_board=arm-sim/-mhard-float/-O3
    --target_board=arm-sim/-mhard-float
    --target_board=arm-sim/-msoft-float/-O1
    --target_board=arm-sim/-msoft-float/-O2
    --target_board=arm-sim/-msoft-float/-O3
    --target_board=arm-sim/-msoft-float
@end example

They can be combined as many times as you wish, in arbitrary ways.  This
list:

@example
    @dots{}"--target_board=unix/-Wextra@{-O3,-fno-strength-reduce@}@{-fomit-frame-pointer,@}"
@end example

will generate four combinations, all involving @samp{-Wextra}.

The disadvantage to this method is that the testsuites are run in serial,
which is a waste on multiprocessor systems.  For users with GNU Make and
a shell which performs brace expansion, you can run the testsuites in
parallel by having the shell perform the combinations and @command{make}
do the parallel runs.  Instead of using @samp{--target_board}, use a
special makefile target:

@example
    make -j@var{N} check-@var{testsuite}//@var{test-target}/@var{option1}/@var{option2}/@dots{}
@end example

For example,

@example
    make -j3 check-gcc//sh-hms-sim/@{-m1,-m2,-m3,-m3e,-m4@}/@{,-nofpu@}
@end example

will run three concurrent ``make-gcc'' testsuites, eventually testing all
ten combinations as described above.  Note that this is currently only
supported in the @file{gcc} subdirectory.  (To see how this works, try
typing @command{echo} before the example given here.)


@section Additional testing for Java Class Libraries

The Java runtime tests can be executed via @samp{make check}
in the @file{@var{target}/libjava/testsuite} directory in
the build tree.

The @uref{http://sources.redhat.com/mauve/,,Mauve Project} provides
a suite of tests for the Java Class Libraries.  This suite can be run
as part of libgcj testing by placing the Mauve tree within the libjava
testsuite at @file{libjava/testsuite/libjava.mauve/mauve}, or by
specifying the location of that tree when invoking @samp{make}, as in
@samp{make MAUVEDIR=~/mauve check}.

@uref{http://www-124.ibm.com/developerworks/oss/cvs/jikes/~checkout~/jacks/jacks.html,,Jacks}
is a free test suite that tests Java compiler front ends.  This suite
can be run as part of libgcj testing by placing the Jacks tree within
the libjava testsuite at @file{libjava/testsuite/libjava.jacks/jacks}.

@section How to interpret test results

The result of running the testsuite are various @file{*.sum} and @file{*.log}
files in the testsuite subdirectories.  The @file{*.log} files contain a
detailed log of the compiler invocations and the corresponding
results, the @file{*.sum} files summarize the results.  These summaries 
contain status codes for all tests: 

@itemize @bullet
@item
PASS: the test passed as expected
@item
XPASS: the test unexpectedly passed
@item
FAIL: the test unexpectedly failed
@item
XFAIL: the test failed as expected
@item
UNSUPPORTED: the test is not supported on this platform
@item
ERROR: the testsuite detected an error
@item
WARNING: the testsuite detected a possible problem
@end itemize

It is normal for some tests to report unexpected failures.  At the
current time our testing harness does not allow fine grained control
over whether or not a test is expected to fail.  We expect to fix this
problem in future releases.


@section Submitting test results

If you want to report the results to the GCC project, use the
@file{contrib/test_summary} shell script.  Start it in the @var{objdir} with

@example
    @var{srcdir}/contrib/test_summary -p your_commentary.txt \
        -m gcc-testresults@@gcc.gnu.org |sh
@end example

This script uses the @command{Mail} program to send the results, so
make sure it is in your @env{PATH}.  The file @file{your_commentary.txt} is
prepended to the testsuite summary and should contain any special
remarks you have on your results or your build environment.  Please
do not edit the testsuite result block or the subject line, as these
messages may be automatically processed.

@html
<hr />
<p>
@end html
@ifhtml
@uref{./index.html,,Return to the GCC Installation page}
@end ifhtml
@end ifset

@c ***Final install***********************************************************
@ifnothtml
@comment node-name,     next,          previous, up
@node    Final install, , Testing, Installing GCC
@end ifnothtml
@ifset finalinstallhtml
@ifnothtml
@chapter Installing GCC: Final installation
@end ifnothtml

Now that GCC has been built (and optionally tested), you can install it with
@example
cd @var{objdir}; make install
@end example

We strongly recommend to install into a target directory where there is
no previous version of GCC present.

That step completes the installation of GCC; user level binaries can
be found in @file{@var{prefix}/bin} where @var{prefix} is the value
you specified with the @option{--prefix} to configure (or
@file{/usr/local} by default).  (If you specified @option{--bindir},
that directory will be used instead; otherwise, if you specified
@option{--exec-prefix}, @file{@var{exec-prefix}/bin} will be used.)
Headers for the C++ and Java libraries are installed in
@file{@var{prefix}/include}; libraries in @file{@var{libdir}}
(normally @file{@var{prefix}/lib}); internal parts of the compiler in
@file{@var{libdir}/gcc} and @file{@var{libexecdir}/gcc}; documentation
in info format in @file{@var{infodir}} (normally
@file{@var{prefix}/info}).

When installing cross-compilers, GCC's executables
are not only installed into @file{@var{bindir}}, that
is, @file{@var{exec-prefix}/bin}, but additionally into
@file{@var{exec-prefix}/@var{target-alias}/bin}, if that directory
exists.  Typically, such @dfn{tooldirs} hold target-specific
binutils, including assembler and linker.

Installation into a temporary staging area or into a @command{chroot}
jail can be achieved with the command

@example
make DESTDIR=@var{path-to-rootdir} install
@end example

@noindent where @var{path-to-rootdir} is the absolute path of
a directory relative to which all installation paths will be
interpreted.  Note that the directory specified by @code{DESTDIR}
need not exist yet; it will be created if necessary.

There is a subtle point with tooldirs and @code{DESTDIR}:
If you relocate a cross-compiler installation with
e.g.@: @samp{DESTDIR=@var{rootdir}}, then the directory
@file{@var{rootdir}/@var{exec-prefix}/@var{target-alias}/bin} will
be filled with duplicated GCC executables only if it already exists,
it will not be created otherwise.  This is regarded as a feature,
not as a bug, because it gives slightly more control to the packagers
using the @code{DESTDIR} feature.

If you built a released version of GCC using @samp{make bootstrap} then please
quickly review the build status page for your release, available from
@uref{http://gcc.gnu.org/buildstat.html}.
If your system is not listed for the version of GCC that you built,
send a note to
@email{gcc@@gcc.gnu.org} indicating
that you successfully built and installed GCC.
Include the following information:

@itemize @bullet
@item
Output from running @file{@var{srcdir}/config.guess}.  Do not send us
that file itself, just the one-line output from running it.

@item
The output of @samp{gcc -v} for your newly installed gcc.
This tells us which version of GCC you built and the options you passed to
configure.

@item
Whether you enabled all languages or a subset of them.  If you used a
full distribution then this information is part of the configure
options in the output of @samp{gcc -v}, but if you downloaded the
``core'' compiler plus additional front ends then it isn't apparent
which ones you built unless you tell us about it.

@item
If the build was for GNU/Linux, also include:
@itemize @bullet
@item
The distribution name and version (e.g., Red Hat 7.1 or Debian 2.2.3);
this information should be available from @file{/etc/issue}.

@item
The version of the Linux kernel, available from @samp{uname --version}
or @samp{uname -a}.

@item
The version of glibc you used; for RPM-based systems like Red Hat,
Mandrake, and SuSE type @samp{rpm -q glibc} to get the glibc version,
and on systems like Debian and Progeny use @samp{dpkg -l libc6}.
@end itemize
For other systems, you can include similar information if you think it is
relevant.

@item
Any other information that you think would be useful to people building
GCC on the same configuration.  The new entry in the build status list
will include a link to the archived copy of your message.
@end itemize

We'd also like to know if the
@ifnothtml
@ref{Specific, host/target specific installation notes}
@end ifnothtml
@ifhtml
@uref{specific.html,,host/target specific installation notes}
@end ifhtml
didn't include your host/target information or if that information is
incomplete or out of date.  Send a note to
@email{gcc@@gcc.gnu.org} telling us how the information should be changed.

If you find a bug, please report it following our
@uref{../bugs.html,,bug reporting guidelines}.

If you want to print the GCC manuals, do @samp{cd @var{objdir}; make
dvi}.  You will need to have @command{texi2dvi} (version at least 4.2)
and @TeX{} installed.  This creates a number of @file{.dvi} files in
subdirectories of @file{@var{objdir}}; these may be converted for
printing with programs such as @command{dvips}.  You can also
@uref{http://www.gnu.org/order/order.html,,buy printed manuals from the
Free Software Foundation}, though such manuals may not be for the most
recent version of GCC@.

@html
<hr />
<p>
@end html
@ifhtml
@uref{./index.html,,Return to the GCC Installation page}
@end ifhtml
@end ifset

@c ***Binaries****************************************************************
@ifnothtml
@comment node-name,     next,          previous, up
@node    Binaries, Specific, Installing GCC, Top
@end ifnothtml
@ifset binarieshtml
@ifnothtml
@chapter Installing GCC: Binaries
@end ifnothtml
@cindex Binaries
@cindex Installing GCC: Binaries

We are often asked about pre-compiled versions of GCC@.  While we cannot
provide these for all platforms, below you'll find links to binaries for
various platforms where creating them by yourself is not easy due to various
reasons.

Please note that we did not create these binaries, nor do we
support them.  If you have any problems installing them, please
contact their makers.

@itemize
@item
AIX:
@itemize
@item
@uref{http://www.bullfreeware.com,,Bull's Freeware and Shareware Archive for AIX};

@item
@uref{http://aixpdslib.seas.ucla.edu,,UCLA Software Library for AIX}.
@end itemize

@item
DOS---@uref{http://www.delorie.com/djgpp/,,DJGPP}.

@item
Renesas H8/300[HS]---@uref{http://h8300-hms.sourceforge.net/,,GNU
Development Tools for the Renesas H8/300[HS] Series}.

@item
HP-UX:
@itemize
@item
@uref{http://hpux.cae.wisc.edu/,,HP-UX Porting Center};

@item
@uref{ftp://sunsite.informatik.rwth-aachen.de/pub/packages/gcc_hpux/,,Binaries for HP-UX 11.00 at Aachen University of Technology}.
@end itemize

@item
Motorola 68HC11/68HC12---@uref{http://www.gnu-m68hc11.org,,GNU
Development Tools for the Motorola 68HC11/68HC12}.

@item
@uref{http://www.sco.com/skunkware/devtools/index.html#gcc,,SCO
OpenServer/Unixware}.

@item
Sinix/Reliant Unix---@uref{ftp://ftp.fujitsu-siemens.com/pub/pd/gnu/gcc/,,Siemens}.
 
@item
Solaris 2 (SPARC, Intel)---@uref{http://www.sunfreeware.com/,,Sunfreeware}.

@item
SGI---@uref{http://freeware.sgi.com/,,SGI Freeware}.

@item
Microsoft Windows:
@itemize
@item
The @uref{http://sources.redhat.com/cygwin/,,Cygwin} project;
@item
The @uref{http://www.mingw.org/,,MinGW} project.
@end itemize

@item
@uref{ftp://ftp.thewrittenword.com/packages/by-name/,,The
Written Word} offers binaries for
AIX 4.3.2.
IRIX 6.5,
Digital UNIX 4.0D and 5.1,
GNU/Linux (i386),
HP-UX 10.20, 11.00, and 11.11, and
Solaris/SPARC 2.5.1, 2.6, 2.7, 8, and 9,
@end itemize

In addition to those specific offerings, you can get a binary
distribution CD-ROM from the
@uref{http://www.fsf.org/order/order.html,,Free Software Foundation}.
It contains binaries for a number of platforms, and
includes not only GCC, but other stuff as well.  The current CD does
not contain the latest version of GCC, but it should allow
bootstrapping the compiler.  An updated version of that disk is in the
works.

@html
<hr />
<p>
@end html
@ifhtml
@uref{./index.html,,Return to the GCC Installation page}
@end ifhtml
@end ifset

@c ***Specific****************************************************************
@ifnothtml
@comment node-name,     next,          previous, up
@node    Specific, Old, Binaries, Top
@end ifnothtml
@ifset specifichtml
@ifnothtml
@chapter Host/target specific installation notes for GCC
@end ifnothtml
@cindex Specific
@cindex Specific installation notes
@cindex Target specific installation
@cindex Host specific installation
@cindex Target specific installation notes

Please read this document carefully @emph{before} installing the
GNU Compiler Collection on your machine.

@ifhtml
@itemize
@item
@uref{#alpha*-*-*,,alpha*-*-*}
@item
@uref{#alpha*-dec-osf*,,alpha*-dec-osf*}
@item
@uref{#alphaev5-cray-unicosmk*,,alphaev5-cray-unicosmk*}
@item
@uref{#arc-*-elf,,arc-*-elf}
@item
@uref{#arm-*-elf,,arm-*-elf}
@uref{#arm-*-coff,,arm-*-coff}
@uref{#arm-*-aout,,arm-*-aout}
@item
@uref{#xscale-*-*,,xscale-*-*}
@item
@uref{#avr,,avr}
@item
@uref{#c4x,,c4x}
@item
@uref{#dos,,DOS}
@item
@uref{#dsp16xx,,dsp16xx}
@item
@uref{#*-*-freebsd*,,*-*-freebsd*}
@item
@uref{#h8300-hms,,h8300-hms}
@item
@uref{#hppa*-hp-hpux*,,hppa*-hp-hpux*}
@item
@uref{#hppa*-hp-hpux10,,hppa*-hp-hpux10}
@item
@uref{#hppa*-hp-hpux11,,hppa*-hp-hpux11}
@item
@uref{#i370-*-*,,i370-*-*}
@item
@uref{#*-*-linux-gnu,,*-*-linux-gnu}
@item
@uref{#ix86-*-linux*aout,,i?86-*-linux*aout}
@item
@uref{#ix86-*-linux*,,i?86-*-linux*}
@item
@uref{#ix86-*-sco3.2v5*,,i?86-*-sco3.2v5*}
@item
@uref{#ix86-*-udk,,i?86-*-udk}
@item
@uref{#ix86-*-esix,,i?86-*-esix}
@item
@uref{#ia64-*-linux,,ia64-*-linux}
@item
@uref{#ia64-*-hpux*,,ia64-*-hpux*}
@item
@uref{#*-ibm-aix*,,*-ibm-aix*}
@item
@uref{#ip2k-*-elf,,ip2k-*-elf}
@item
@uref{#iq2000-*-elf,,iq2000-*-elf}
@item
@uref{#m32r-*-elf,,m32r-*-elf}
@item
@uref{#m6811-elf,,m6811-elf}
@item
@uref{#m6812-elf,,m6812-elf}
@item
@uref{#m68k-hp-hpux,,m68k-hp-hpux}
@item
@uref{#mips-*-*,,mips-*-*}
@item
@uref{#mips-sgi-irix5,,mips-sgi-irix5}
@item
@uref{#mips-sgi-irix6,,mips-sgi-irix6}
@item
@uref{#powerpc*-*-*,,powerpc*-*-*, powerpc-*-sysv4}
@item
@uref{#powerpc-*-darwin*,,powerpc-*-darwin*}
@item
@uref{#powerpc-*-elf,,powerpc-*-elf, powerpc-*-sysv4}
@item
@uref{#powerpc-*-linux-gnu*,,powerpc-*-linux-gnu*}
@item
@uref{#powerpc-*-netbsd*,,powerpc-*-netbsd*}
@item
@uref{#powerpc-*-eabiaix,,powerpc-*-eabiaix}
@item
@uref{#powerpc-*-eabisim,,powerpc-*-eabisim}
@item
@uref{#powerpc-*-eabi,,powerpc-*-eabi}
@item
@uref{#powerpcle-*-elf,,powerpcle-*-elf, powerpcle-*-sysv4}
@item
@uref{#powerpcle-*-eabisim,,powerpcle-*-eabisim}
@item
@uref{#powerpcle-*-eabi,,powerpcle-*-eabi}
@item
@uref{#s390-*-linux*,,s390-*-linux*}
@item
@uref{#s390x-*-linux*,,s390x-*-linux*}
@item
@uref{#s390x-ibm-tpf*,,s390x-ibm-tpf*}
@item
@uref{#*-*-solaris2*,,*-*-solaris2*}
@item
@uref{#sparc-sun-solaris2*,,sparc-sun-solaris2*}
@item
@uref{#sparc-sun-solaris2.7,,sparc-sun-solaris2.7}
@item
@uref{#sparc-*-linux*,,sparc-*-linux*}
@item
@uref{#sparc64-*-solaris2*,,sparc64-*-solaris2*}
@item
@uref{#sparcv9-*-solaris2*,,sparcv9-*-solaris2*}
@item
@uref{#*-*-sysv*,,*-*-sysv*}
@item
@uref{#vax-dec-ultrix,,vax-dec-ultrix}
@item
@uref{#*-*-vxworks*,,*-*-vxworks*}
@item
@uref{#xtensa-*-elf,,xtensa-*-elf}
@item
@uref{#xtensa-*-linux*,,xtensa-*-linux*}
@item
@uref{#windows,,Microsoft Windows}
@item
@uref{#os2,,OS/2}
@item
@uref{#older,,Older systems}
@end itemize

@itemize
@item
@uref{#elf_targets,,all ELF targets} (SVR4, Solaris 2, etc.)
@end itemize
@end ifhtml


@html
<!-- -------- host/target specific issues start here ---------------- -->
<hr />
@end html
@heading @anchor{alpha*-*-*}alpha*-*-*

This section contains general configuration information for all
alpha-based platforms using ELF (in particular, ignore this section for
DEC OSF/1, Digital UNIX and Tru64 UNIX)@.  In addition to reading this
section, please read all other sections that match your target.

We require binutils 2.11.2 or newer.
Previous binutils releases had a number of problems with DWARF 2
debugging information, not the least of which is incorrect linking of
shared libraries.

@html
<hr />
@end html
@heading @anchor{alpha*-dec-osf*}alpha*-dec-osf*
Systems using processors that implement the DEC Alpha architecture and
are running the DEC/Compaq Unix (DEC OSF/1, Digital UNIX, or Compaq
Tru64 UNIX) operating system, for example the DEC Alpha AXP systems.

As of GCC 3.2, versions before @code{alpha*-dec-osf4} are no longer
supported.  (These are the versions which identify themselves as DEC
OSF/1.)

In Digital Unix V4.0, virtual memory exhausted bootstrap failures
may be fixed by configuring with @option{--with-gc=simple},
reconfiguring Kernel Virtual Memory and Swap parameters
per the @command{/usr/sbin/sys_check} Tuning Suggestions,
or applying the patch in
@uref{http://gcc.gnu.org/ml/gcc/2002-08/msg00822.html}.

In Tru64 UNIX V5.1, Compaq introduced a new assembler that does not
currently (2001-06-13) work with @command{mips-tfile}.  As a workaround,
we need to use the old assembler, invoked via the barely documented
@option{-oldas} option.  To bootstrap GCC, you either need to use the
Compaq C Compiler:

@example
   % CC=cc @var{srcdir}/configure [@var{options}] [@var{target}]
@end example

or you can use a copy of GCC 2.95.3 or higher built on Tru64 UNIX V4.0:

@example
   % CC=gcc -Wa,-oldas @var{srcdir}/configure [@var{options}] [@var{target}]
@end example

As of GNU binutils 2.11.2, neither GNU @command{as} nor GNU @command{ld}
are supported on Tru64 UNIX, so you must not configure GCC with
@option{--with-gnu-as} or @option{--with-gnu-ld}.

GCC writes a @samp{.verstamp} directive to the assembler output file
unless it is built as a cross-compiler.  It gets the version to use from
the system header file @file{/usr/include/stamp.h}.  If you install a
new version of DEC Unix, you should rebuild GCC to pick up the new version
stamp.

Note that since the Alpha is a 64-bit architecture, cross-compilers from
32-bit machines will not generate code as efficient as that generated
when the compiler is running on a 64-bit machine because many
optimizations that depend on being able to represent a word on the
target in an integral value on the host cannot be performed.  Building
cross-compilers on the Alpha for 32-bit machines has only been tested in
a few cases and may not work properly.

@samp{make compare} may fail on old versions of DEC Unix unless you add
@option{-save-temps} to @code{CFLAGS}.  On these systems, the name of the
assembler input file is stored in the object file, and that makes
comparison fail if it differs between the @code{stage1} and
@code{stage2} compilations.  The option @option{-save-temps} forces a
fixed name to be used for the assembler input file, instead of a
randomly chosen name in @file{/tmp}.  Do not add @option{-save-temps}
unless the comparisons fail without that option.  If you add
@option{-save-temps}, you will have to manually delete the @samp{.i} and
@samp{.s} files after each series of compilations.

GCC now supports both the native (ECOFF) debugging format used by DBX
and GDB and an encapsulated STABS format for use only with GDB@.  See the
discussion of the @option{--with-stabs} option of @file{configure} above
for more information on these formats and how to select them.

There is a bug in DEC's assembler that produces incorrect line numbers
for ECOFF format when the @samp{.align} directive is used.  To work
around this problem, GCC will not emit such alignment directives
while writing ECOFF format debugging information even if optimization is
being performed.  Unfortunately, this has the very undesirable
side-effect that code addresses when @option{-O} is specified are
different depending on whether or not @option{-g} is also specified.

To avoid this behavior, specify @option{-gstabs+} and use GDB instead of
DBX@.  DEC is now aware of this problem with the assembler and hopes to
provide a fix shortly.

@html
<hr />
@end html
@heading @anchor{alphaev5-cray-unicosmk*}alphaev5-cray-unicosmk*
Cray T3E systems running Unicos/Mk.

This port is incomplete and has many known bugs.  We hope to improve the
support for this target soon.  Currently, only the C front end is supported,
and it is not possible to build parallel applications.  Cray modules are not
supported; in particular, Craylibs are assumed to be in
@file{/opt/ctl/craylibs/craylibs}.

You absolutely @strong{must} use GNU make on this platform.  Also, you
need to tell GCC where to find the assembler and the linker.  The
simplest way to do so is by providing @option{--with-as} and
@option{--with-ld} to @file{configure}, e.g.@:

@example
    configure --with-as=/opt/ctl/bin/cam --with-ld=/opt/ctl/bin/cld \
      --enable-languages=c
@end example

The comparison test during @samp{make bootstrap} fails on Unicos/Mk
because the assembler inserts timestamps into object files.  You should
be able to work around this by doing @samp{make all} after getting this
failure.

@html
<hr />
@end html
@heading @anchor{arc-*-elf}arc-*-elf
Argonaut ARC processor.
This configuration is intended for embedded systems.

@html
<hr />
@end html
@heading @anchor{arm-*-elf}arm-*-elf
@heading @anchor{xscale-*-*}xscale-*-*
ARM-family processors.  Subtargets that use the ELF object format
require GNU binutils 2.13 or newer.  Such subtargets include:
@code{arm-*-freebsd}, @code{arm-*-netbsdelf}, @code{arm-*-*linux},
@code{arm-*-rtems} and @code{arm-*-kaos}.

@html
<hr />
@end html
@heading @anchor{arm-*-coff}arm-*-coff
ARM-family processors.  Note that there are two different varieties
of PE format subtarget supported: @code{arm-wince-pe} and
@code{arm-pe} as well as a standard COFF target @code{arm-*-coff}.

@html
<hr />
@end html
@heading @anchor{arm-*-aout}arm-*-aout
ARM-family processors.  These targets support the AOUT file format:
@code{arm-*-aout}, @code{arm-*-netbsd}.

@html
<hr />
@end html
@heading @anchor{avr}avr

ATMEL AVR-family micro controllers.  These are used in embedded
applications.  There are no standard Unix configurations.
@ifnothtml
@xref{AVR Options,, AVR Options, gcc, Using and Porting the GNU Compiler
Collection (GCC)},
@end ifnothtml
@ifhtml
See ``AVR Options'' in the main manual
@end ifhtml
for the list of supported MCU types.

Use @samp{configure --target=avr --enable-languages="c"} to configure GCC@.

Further installation notes and other useful information about AVR tools
can also be obtained from:

@itemize @bullet
@item
@uref{http://www.openavr.org,,http://www.openavr.org}
@item
@uref{http://home.overta.ru/users/denisc/,,http://home.overta.ru/users/denisc/}
@item
@uref{http://www.amelek.gda.pl/avr/,,http://www.amelek.gda.pl/avr/}
@end itemize

We @emph{strongly} recommend using binutils 2.13 or newer.

The following error:
@example
  Error: register required
@end example

indicates that you should upgrade to a newer version of the binutils.

@html
<hr />
@end html
@heading @anchor{c4x}c4x

Texas Instruments TMS320C3x and TMS320C4x Floating Point Digital Signal
Processors.  These are used in embedded applications.  There are no
standard Unix configurations.
@ifnothtml
@xref{TMS320C3x/C4x Options,, TMS320C3x/C4x Options, gcc, Using and
Porting the GNU Compiler Collection (GCC)},
@end ifnothtml
@ifhtml
See ``TMS320C3x/C4x Options'' in the main manual
@end ifhtml
for the list of supported MCU types.

GCC can be configured as a cross compiler for both the C3x and C4x
architectures on the same system.  Use @samp{configure --target=c4x
--enable-languages="c,c++"} to configure.


Further installation notes and other useful information about C4x tools
can also be obtained from:

@itemize @bullet
@item
@uref{http://www.elec.canterbury.ac.nz/c4x/,,http://www.elec.canterbury.ac.nz/c4x/}
@end itemize

@html
<hr />
@end html
@heading @anchor{cris}CRIS

CRIS is the CPU architecture in Axis Communications ETRAX system-on-a-chip
series.  These are used in embedded applications.

@ifnothtml
@xref{CRIS Options,, CRIS Options, gcc, Using and Porting the GNU Compiler
Collection (GCC)},
@end ifnothtml
@ifhtml
See ``CRIS Options'' in the main manual
@end ifhtml
for a list of CRIS-specific options.

There are a few different CRIS targets:
@table @code
@item cris-axis-aout
Old target.  Includes a multilib for the @samp{elinux} a.out-based
target.  No multilibs for newer architecture variants.
@item cris-axis-elf
Mainly for monolithic embedded systems.  Includes a multilib for the
@samp{v10} core used in @samp{ETRAX 100 LX}.
@item cris-axis-linux-gnu
A GNU/Linux port for the CRIS architecture, currently targeting
@samp{ETRAX 100 LX} by default.
@end table

For @code{cris-axis-aout} and @code{cris-axis-elf} you need binutils 2.11
or newer.  For @code{cris-axis-linux-gnu} you need binutils 2.12 or newer.

Pre-packaged tools can be obtained from
@uref{ftp://ftp.axis.com/pub/axis/tools/cris/compiler-kit/}.  More
information about this platform is available at
@uref{http://developer.axis.com/}.

@html
<hr />
@end html
@heading @anchor{dos}DOS

Please have a look at our @uref{binaries.html,,binaries page}.

You cannot install GCC by itself on MSDOS; it will not compile under
any MSDOS compiler except itself.  You need to get the complete
compilation package DJGPP, which includes binaries as well as sources,
and includes all the necessary compilation tools and libraries.

@html
<hr />
@end html
@heading @anchor{dsp16xx}dsp16xx
A port to the AT&T DSP1610 family of processors.

@html
<hr />
@end html
@heading @anchor{*-*-freebsd*}*-*-freebsd*

The version of binutils installed in @file{/usr/bin} is known to work unless
otherwise specified in any per-architecture notes.  However, binutils
2.12.1 or greater is known to improve overall testsuite results.

Support for FreeBSD 1 was discontinued in GCC 3.2.

For FreeBSD 2 or any mutant a.out versions of FreeBSD 3: All
configuration support and files as shipped with GCC 2.95 are still in
place.  FreeBSD 2.2.7 has been known to bootstrap completely; however,
it is unknown which version of binutils was used (it is assumed that it
was the system copy in @file{/usr/bin}) and C++ EH failures were noted.

For FreeBSD using the ELF file format: DWARF 2 debugging is now the
default for all CPU architectures.  It had been the default on
FreeBSD/alpha since its inception.  You may use @option{-gstabs} instead
of @option{-g}, if you really want the old debugging format.  There are
no known issues with mixing object files and libraries with different
debugging formats.  Otherwise, this release of GCC should now match more
of the configuration used in the stock FreeBSD configuration of GCC.  In
particular, @option{--enable-threads} is now configured by default.
However, as a general user, do not attempt to replace the system
compiler with this release.  Known to bootstrap and check with good
results on FreeBSD 4.8-STABLE and 5-CURRENT@.  In the past, known to
bootstrap and check with good results on FreeBSD 3.0, 3.4, 4.0, 4.2,
4.3, 4.4, 4.5-STABLE@.

In principle, @option{--enable-threads} is now compatible with
@option{--enable-libgcj} on FreeBSD@.  However, it has only been built
and tested on @samp{i386-*-freebsd[45]} and @samp{alpha-*-freebsd[45]}.
The static
library may be incorrectly built (symbols are missing at link time).
There is a rare timing-based startup hang (probably involves an
assumption about the thread library).  Multi-threaded boehm-gc (required for
libjava) exposes severe threaded signal-handling bugs on FreeBSD before
4.5-RELEASE@.  Other CPU architectures
supported by FreeBSD will require additional configuration tuning in, at
the very least, both boehm-gc and libffi.

Shared @file{libgcc_s.so} is now built and installed by default.

@html
<hr />
@end html
@heading @anchor{h8300-hms}h8300-hms
Renesas H8/300 series of processors.

Please have a look at our @uref{binaries.html,,binaries page}.

The calling convention and structure layout has changed in release 2.6.
All code must be recompiled.  The calling convention now passes the
first three arguments in function calls in registers.  Structures are no
longer a multiple of 2 bytes.

@html
<hr />
@end html
@heading @anchor{hppa*-hp-hpux*}hppa*-hp-hpux*
Support for HP-UX version 9 and older was discontinued in GCC 3.4.

We @emph{highly} recommend using gas/binutils 2.8 or newer on all hppa
platforms; you may encounter a variety of problems when using the HP
assembler.

Specifically, @option{-g} does not work on HP-UX (since that system
uses a peculiar debugging format which GCC does not know about), unless you
use GAS and GDB and configure GCC with the
@uref{./configure.html#with-gnu-as,,@option{--with-gnu-as}} and
@option{--with-as=@dots{}} options.

If you wish to use the pa-risc 2.0 architecture support with a 32-bit
runtime, you must use either the HP assembler, gas/binutils 2.11 or newer,
or a recent
@uref{ftp://sources.redhat.com/pub/binutils/snapshots,,snapshot of gas}.

There are two default scheduling models for instructions.  These are
PROCESSOR_7100LC and PROCESSOR_8000.  They are selected from the pa-risc
architecture specified for the target machine when configuring.
PROCESSOR_8000 is the default.  PROCESSOR_7100LC is selected when
the target is a @samp{hppa1*} machine.

The PROCESSOR_8000 model is not well suited to older processors.  Thus,
it is important to completely specify the machine architecture when
configuring if you want a model other than PROCESSOR_8000.  The macro
TARGET_SCHED_DEFAULT can be defined in BOOT_CFLAGS if a different
default scheduling model is desired.

More specific information to @samp{hppa*-hp-hpux*} targets follows.

@html
<hr />
@end html
@heading @anchor{hppa*-hp-hpux10}hppa*-hp-hpux10

For hpux10.20, we @emph{highly} recommend you pick up the latest sed patch
@code{PHCO_19798} from HP@.  HP has two sites which provide patches free of
charge:

@itemize @bullet
@item
@html
<a href="http://us.itrc.hp.com/service/home/home.do">US, Canada, Asia-Pacific, and
Latin-America</a>
@end html
@ifnothtml
@uref{http://us.itrc.hp.com/service/home/home.do,,} US, Canada, Asia-Pacific,
and Latin-America.
@end ifnothtml
@item
@uref{http://europe.itrc.hp.com/service/home/home.do,,} Europe.
@end itemize

The HP assembler on these systems has some problems.  Most notably the
assembler inserts timestamps into each object file it creates, causing
the 3-stage comparison test to fail during a @samp{make bootstrap}.
You should be able to continue by saying @samp{make all} after getting
the failure from @samp{make bootstrap}.


@html
<hr />
@end html
@heading @anchor{hppa*-hp-hpux11}hppa*-hp-hpux11

GCC 3.0 and up support HP-UX 11.  On 64-bit capable systems, there
are two distinct ports.  The @samp{hppa2.0w-hp-hpux11*} port generates
code for the 32-bit pa-risc runtime architecture.  It uses the HP
linker.  The @samp{hppa64-hp-hpux11*} port generates 64-bit code for the
pa-risc 2.0 architecture.  The script config.guess now selects the port
type based on the type compiler detected during configuration.  You must
set your @env{PATH} or define @env{CC} so that configure finds an appropriate
compiler for the initial bootstrap.  Different prefixes must be used if
both ports are to be installed on the same system.

It is best to explicitly configure the @samp{hppa64-hp-hpux11*} target
with the @option{--with-ld=@dots{}} option.  We support both the HP
and GNU linkers for this target.  The two linkers require different
link commands.  Thus, it's not possible to switch linkers during a
GCC build.  This has been been reported to occur in a unified build
of binutils and GCC.

GCC 2.95.x is not supported under HP-UX 11 and cannot be used to
compile GCC 3.0 and up.  Refer to @uref{binaries.html,,binaries} for
information about obtaining precompiled GCC binaries for HP-UX.

You must use GNU binutils 2.11 or above with the 32-bit port.  Thread
support is not currently implemented, so @option{--enable-threads} does
not work.  See:

@itemize
@item @uref{http://gcc.gnu.org/ml/gcc-prs/2002-01/msg00551.html}
@item @uref{http://gcc.gnu.org/ml/gcc-bugs/2002-01/msg00663.html}
@end itemize

GCC 3.3 and later support weak symbols on the 32-bit port using SOM
secondary definition symbols.  This feature is not enabled for earlier
versions of HP-UX since there have been bugs in the linker support for
secondary symbols.  The HP linker patches @code{PHSS_26559} and
@code{PHSS_24304} for HP-UX 11.00 and 11.11, respectively, correct the
problem of linker core dumps creating C++ libraries.  Earlier patches
may work but they have not been tested.

GCC 3.3 nows uses the ELF DT_INIT_ARRAY and DT_FINI_ARRAY capability
to run initializers and finalizers on the 64-bit port.  The feature
requires CVS binutils as of January 2, 2003, or a subsequent release
to correct a problem arising from HP's non-standard use of the .init
and .fini sections.  The 32-bit port uses the linker @option{+init}
and @option{+fini} options.  As with the support for secondary symbols,
there have been bugs in the order in which these options are executed
by the HP linker.  So, again a recent linker patch is recommended.

The HP assembler has many limitations and is not recommended for either
the 32 or 64-bit ports.  For example, it does not support weak symbols
or alias definitions.  As a result, explicit template instantiations
are required when using C++.  This will make it difficult if not
impossible to build many C++ applications.  You also can't generate
debugging information when using the HP assembler with GCC.

There are a number of issues to consider in selecting which linker to
use with the 64-bit port.  The  GNU 64-bit linker can only create dynamic
binaries.  The @option{-static} option causes linking with archive
libraries but doesn't produce a truly static binary.  Dynamic binaries
still require final binding by the dynamic loader to resolve a set of
dynamic-loader-defined symbols.  The default behavior of the HP linker
is the same as the GNU linker.  However, it can generate true 64-bit
static binaries using the @option{+compat} option.

The HP 64-bit linker doesn't support linkonce semantics.  As a
result, C++ programs have many more sections than they should.

The GNU 64-bit linker has some issues with shared library support
and exceptions.  As a result, we only support libgcc in archive
format.  For similar reasons, dwarf2 unwind and exception support
are disabled.  The GNU linker also has problems creating binaries
with @option{-static}.  It doesn't provide stubs for internal
calls to global functions in shared libraries, so these calls
can't be overloaded.

There are several possible approaches to building the distribution.
Binutils can be built first using the HP tools.  Then, the GCC
distribution can be built.  The second approach is to build GCC
first using the HP tools, then build binutils, then rebuild GCC.
There have been problems with various binary distributions, so
it is best not to start from a binary distribution.

Starting with GCC 3.4 an ISO C compiler is required to bootstrap.
The bundled compiler supports only traditional C; you will need
either HP's unbundled compiler, or a binary distribution of GCC@.

This port still is undergoing significant development.

@html
<hr />
@end html
@heading @anchor{i370-*-*}i370-*-*
This port is very preliminary and has many known bugs.  We hope to
have a higher-quality port for this machine soon.

@html
<hr />
@end html
@heading @anchor{*-*-linux-gnu}*-*-linux-gnu

Versions of libstdc++-v3 starting with 3.2.1 require bugfixes present
in glibc 2.2.5 and later.  More information is available in the
libstdc++-v3 documentation.

@html
<hr />
@end html
@heading @anchor{ix86-*-linux*aout}i?86-*-linux*aout
Use this configuration to generate @file{a.out} binaries on Linux-based
GNU systems.  This configuration is being superseded.

@html
<hr />
@end html
@heading @anchor{ix86-*-linux*}i?86-*-linux*

As of GCC 3.3, binutils 2.13.1 or later is required for this platform.
See @uref{http://gcc.gnu.org/PR10877,,bug 10877} for more information.

If you receive Signal 11 errors when building on GNU/Linux, then it is
possible you have a hardware problem.  Further information on this can be
found on @uref{http://www.bitwizard.nl/sig11/,,www.bitwizard.nl}.

@html
<hr />
@end html
@heading @anchor{ix86-*-sco3.2v5*}i?86-*-sco3.2v5*
Use this for the SCO OpenServer Release 5 family of operating systems.

Unlike earlier versions of GCC, the ability to generate COFF with this
target is no longer provided.

Earlier versions of GCC emitted DWARF 1 when generating ELF to allow
the system debugger to be used.  That support was too burdensome to
maintain.  GCC now emits only DWARF 2 for this target.  This means you
may use either the UDK debugger or GDB to debug programs built by this
version of GCC@.

GCC is now only supported on releases 5.0.4 and later, and requires that
you install Support Level Supplement OSS646B or later, and Support Level
Supplement OSS631C or later.  If you are using release 5.0.7 of
OpenServer, you must have at least the first maintenance pack installed
(this includes the relevant portions of OSS646).  OSS646, also known as
the "Execution Environment Update", provides updated link editors and
assemblers, as well as updated standard C and math libraries.  The C
startup modules are also updated to support the System V gABI draft, and
GCC relies on that behavior.  OSS631 provides a collection of commonly
used open source libraries, some of which GCC depends on (such as GNU
gettext and zlib).  SCO OpenServer Release 5.0.7 has all of this built
in by default, but OSS631C and later also apply to that release.  Please
visit
@uref{ftp://ftp.sco.com/pub/openserver5,,ftp://ftp.sco.com/pub/openserver5}
for the latest versions of these (and other potentially useful)
supplements.

Although there is support for using the native assembler, it is
recommended that you configure GCC to use the GNU assembler.  You do
this by using the flags
@uref{./configure.html#with-gnu-as,,@option{--with-gnu-as}}.  You should
use a modern version of GNU binutils.  Version 2.13.2.1 was used for all
testing.  In general, only the @option{--with-gnu-as} option is tested.
A modern bintuils (as well as a plethora of other development related
GNU utilities) can be found in Support Level Supplement OSS658A, the
"GNU Development Tools" package.  See the SCO web and ftp sites for details.
That package also contains the currently "officially supported" version of
GCC, version 2.95.3.  It is useful for bootstrapping this version.  

@html
<hr />
@end html
@heading @anchor{ix86-*-udk}i?86-*-udk

This target emulates the SCO Universal Development Kit and requires that
package be installed.  (If it is installed, you will have a
@file{/udk/usr/ccs/bin/cc} file present.)  It's very much like the
@samp{i?86-*-unixware7*} target
but is meant to be used when hosting on a system where UDK isn't the
default compiler such as OpenServer 5 or Unixware 2.  This target will
generate binaries that will run on OpenServer, Unixware 2, or Unixware 7,
with the same warnings and caveats as the SCO UDK@.

This target is a little tricky to build because we have to distinguish
it from the native tools (so it gets headers, startups, and libraries
from the right place) while making the tools not think we're actually
building a cross compiler.   The easiest way to do this is with a configure
command like this:

@example
    CC=/udk/usr/ccs/bin/cc @var{/your/path/to}/gcc/configure \
      --host=i686-pc-udk --target=i686-pc-udk --program-prefix=udk-
@end example

@emph{You should substitute @samp{i686} in the above command with the appropriate
processor for your host.}

After the usual @samp{make bootstrap} and
@samp{make install}, you can then access the UDK-targeted GCC
tools by adding @command{udk-} before the commonly known name.  For
example, to invoke the C compiler, you would use @command{udk-gcc}.
They will coexist peacefully with any native-target GCC tools you may
have installed.


@html
<hr />
@end html
@heading @anchor{ia64-*-linux}ia64-*-linux
IA-64 processor (also known as IPF, or Itanium Processor Family)
running GNU/Linux.

None of the following versions of GCC has an ABI that is compatible
with any of the other versions in this list, with the exception that
Red Hat 2.96 and Trillian 000171 are compatible with each other:
3.1, 3.0.2, 3.0.1, 3.0, Red Hat 2.96, and Trillian 000717.
This primarily affects C++ programs and programs that create shared libraries.
GCC 3.1 or later is recommended for compiling linux, the kernel.
As of version 3.1 GCC is believed to be fully ABI compliant, and hence no
more major ABI changes are expected.

@html
<hr />
@end html
@heading @anchor{ia64-*-hpux*}ia64-*-hpux*
Building GCC on this target requires the GNU Assembler. The bundled HP
assembler will not work. To prevent GCC from using the wrong assembler,
the option @option{--with-gnu-as} may be necessary.

The GCC libunwind library has not been ported to HPUX. This means that for
GCC versions 3.2.3 and earlier, @option{--enable-libunwind-exceptions}
is required to build GCC. For GCC 3.3 and later, this is the default.

@html
<hr />
<!-- rs6000-ibm-aix*, powerpc-ibm-aix* -->
@end html
@heading @anchor{*-ibm-aix*}*-ibm-aix*
Support for AIX version 3 and older was discontinued in GCC 3.4.

AIX Make frequently has problems with GCC makefiles.  GNU Make 3.79.1 or
newer is recommended to build on this platform.

Errors involving @code{alloca} when building GCC generally are due
to an incorrect definition of @code{CC} in the Makefile or mixing files
compiled with the native C compiler and GCC@.  During the stage1 phase of
the build, the native AIX compiler @strong{must} be invoked as @command{cc}
(not @command{xlc}).  Once @command{configure} has been informed of
@command{xlc}, one needs to use @samp{make distclean} to remove the
configure cache files and ensure that @env{CC} environment variable
does not provide a definition that will confuse @command{configure}.
If this error occurs during stage2 or later, then the problem most likely
is the version of Make (see above).

The native @command{as} and @command{ld} are recommended for bootstrapping
on AIX 4 and required for bootstrapping on AIX 5L.  The GNU Assembler
reports that it supports WEAK symbols on AIX 4, which causes GCC to try to
utilize weak symbol functionality although it is not supported.  The GNU
Assembler and Linker do not support AIX 5L sufficiently to bootstrap GCC.
The native AIX tools do interoperate with GCC@.

Building @file{libstdc++.a} requires a fix for an AIX Assembler bug
APAR IY26685 (AIX 4.3) or APAR IY25528 (AIX 5.1).

@samp{libstdc++} in GCC 3.2 increments the major version number of the
shared object and GCC installation places the @file{libstdc++.a}
shared library in a common location which will overwrite the GCC 3.1
version of the shared library.  Applications either need to be
re-linked against the new shared library or the GCC 3.1 version of the
@samp{libstdc++} shared object needs to be available to the AIX
runtime loader.  The GCC 3.1 @samp{libstdc++.so.4} shared object can
be installed for runtime dynamic loading using the following steps to
set the @samp{F_LOADONLY} flag in the shared object for @emph{each}
multilib @file{libstdc++.a} installed:

Extract the shared object from each the GCC 3.1 @file{libstdc++.a}
archive:
@example
   % ar -x libstdc++.a libstdc++.so.4
@end example

Enable the @samp{F_LOADONLY} flag so that the shared object will be
available for runtime dynamic loading, but not linking:
@example
   % strip -e libstdc++.so.4
@end example

Archive the runtime-only shared object in the GCC 3.2
@file{libstdc++.a} archive:
@example
   % ar -q libstdc++.a libstdc++.so.4
@end example

Linking executables and shared libraries may produce warnings of
duplicate symbols.  The assembly files generated by GCC for AIX always
have included multiple symbol definitions for certain global variable
and function declarations in the original program.  The warnings should
not prevent the linker from producing a correct library or runnable
executable.

AIX 4.3 utilizes a ``large format'' archive to support both 32-bit and
64-bit object modules.  The routines provided in AIX 4.3.0 and AIX 4.3.1
to parse archive libraries did not handle the new format correctly.
These routines are used by GCC and result in error messages during
linking such as ``not a COFF file''.  The version of the routines shipped
with AIX 4.3.1 should work for a 32-bit environment.  The @option{-g}
option of the archive command may be used to create archives of 32-bit
objects using the original ``small format''.  A correct version of the
routines is shipped with AIX 4.3.2 and above.

Some versions of the AIX binder (linker) can fail with a relocation
overflow severe error when the @option{-bbigtoc} option is used to link
GCC-produced object files into an executable that overflows the TOC@.  A fix
for APAR IX75823 (OVERFLOW DURING LINK WHEN USING GCC AND -BBIGTOC) is
available from IBM Customer Support and from its
@uref{http://techsupport.services.ibm.com/,,techsupport.services.ibm.com}
website as PTF U455193.

The AIX 4.3.2.1 linker (bos.rte.bind_cmds Level 4.3.2.1) will dump core
with a segmentation fault when invoked by any version of GCC@.  A fix for
APAR IX87327 is available from IBM Customer Support and from its
@uref{http://techsupport.services.ibm.com/,,techsupport.services.ibm.com}
website as PTF U461879.  This fix is incorporated in AIX 4.3.3 and above.

The initial assembler shipped with AIX 4.3.0 generates incorrect object
files.  A fix for APAR IX74254 (64BIT DISASSEMBLED OUTPUT FROM COMPILER FAILS
TO ASSEMBLE/BIND) is available from IBM Customer Support and from its
@uref{http://techsupport.services.ibm.com/,,techsupport.services.ibm.com}
website as PTF U453956.  This fix is incorporated in AIX 4.3.1 and above.

AIX provides National Language Support (NLS)@.  Compilers and assemblers
use NLS to support locale-specific representations of various data
formats including floating-point numbers (e.g., @samp{.}  vs @samp{,} for
separating decimal fractions).  There have been problems reported where
GCC does not produce the same floating-point formats that the assembler
expects.  If one encounters this problem, set the @env{LANG}
environment variable to @samp{C} or @samp{En_US}.

By default, GCC for AIX 4.1 and above produces code that can be used on
both Power or PowerPC processors.

A default can be specified with the @option{-mcpu=@var{cpu_type}}
switch and using the configure option @option{--with-cpu-@var{cpu_type}}.

@html
<hr />
@end html
@heading @anchor{ip2k-*-elf}ip2k-*-elf
Ubicom IP2022 micro controller.
This configuration is intended for embedded systems.
There are no standard Unix configurations.

Use @samp{configure --target=ip2k-elf --enable-languages=c} to configure GCC@.

@html
<hr />
@end html
@heading @anchor{iq2000-*-elf}iq2000-*-elf
Vitesse IQ2000 processors.  These are used in embedded
applications.  There are no standard Unix configurations.

@html
<hr />
@end html
@heading @anchor{m32r-*-elf}m32r-*-elf
Renesas M32R processor.
This configuration is intended for embedded systems.

@html
<hr />
@end html
@heading @anchor{m6811-elf}m6811-elf
Motorola 68HC11 family micro controllers.  These are used in embedded
applications.  There are no standard Unix configurations.

@html
<hr />
@end html
@heading @anchor{m6812-elf}m6812-elf
Motorola 68HC12 family micro controllers.  These are used in embedded
applications.  There are no standard Unix configurations.

@html
<hr />
@end html
@heading @anchor{m68k-hp-hpux}m68k-hp-hpux
HP 9000 series 300 or 400 running HP-UX@.  HP-UX version 8.0 has a bug in
the assembler that prevents compilation of GCC@.  This
bug manifests itself during the first stage of compilation, while
building @file{libgcc2.a}:

@smallexample
_floatdisf
cc1: warning: `-g' option not supported on this version of GCC
cc1: warning: `-g1' option not supported on this version of GCC
./xgcc: Internal compiler error: program as got fatal signal 11
@end smallexample

A patched version of the assembler is available as the file
@uref{ftp://altdorf.ai.mit.edu/archive/cph/hpux-8.0-assembler}.  If you
have HP software support, the patch can also be obtained directly from
HP, as described in the following note:

@quotation
This is the patched assembler, to patch SR#1653-010439, where the
assembler aborts on floating point constants.

The bug is not really in the assembler, but in the shared library
version of the function ``cvtnum(3c)''.  The bug on ``cvtnum(3c)'' is
SR#4701-078451.  Anyway, the attached assembler uses the archive
library version of ``cvtnum(3c)'' and thus does not exhibit the bug.
@end quotation

This patch is also known as PHCO_4484.

In addition gdb does not understand that native HP-UX format, so
you must use gas if you wish to use gdb.

On HP-UX version 8.05, but not on 8.07 or more recent versions, the
@command{fixproto} shell script triggers a bug in the system shell.  If you
encounter this problem, upgrade your operating system or use BASH (the
GNU shell) to run @command{fixproto}.  This bug will cause the fixproto
program to report an error of the form:

@example
./fixproto: sh internal 1K buffer overflow
@end example

To fix this, you can also change the first line of the fixproto script
to look like:

@example
#!/bin/ksh
@end example

@html
<hr />
@end html
@heading @anchor{mips-*-*}mips-*-*
If on a MIPS system you get an error message saying ``does not have gp
sections for all it's [sic] sectons [sic]'', don't worry about it.  This
happens whenever you use GAS with the MIPS linker, but there is not
really anything wrong, and it is okay to use the output file.  You can
stop such warnings by installing the GNU linker.

It would be nice to extend GAS to produce the gp tables, but they are
optional, and there should not be a warning about their absence.

The libstdc++ atomic locking routines for MIPS targets requires MIPS II
and later.  A patch went in just after the GCC 3.3 release to
make @samp{mips*-*-*} use the generic implementation instead.  You can also
configure for @samp{mipsel-elf} as a workaround.  The
@samp{mips*-*-linux*} target continues to use the MIPS II routines.  More
work on this is expected in future releases.

Cross-compilers for the Mips as target using the Mips assembler
currently do not work, because the auxiliary programs
@file{mips-tdump.c} and @file{mips-tfile.c} can't be compiled on
anything but a Mips.  It does work to cross compile for a Mips
if you use the GNU assembler and linker.

@html
<hr />
@end html
@heading @anchor{mips-sgi-irix5}mips-sgi-irix5

This configuration has considerable problems, which will be fixed in a
future release.

In order to compile GCC on an SGI running IRIX 5, the ``compiler_dev.hdr''
subsystem must be installed from the IDO CD-ROM supplied by Silicon
Graphics.  It is also available for download from
@uref{http://www.sgi.com/developers/devtools/apis/ido.html,,http://www.sgi.com/developers/devtools/apis/ido.html}.

@samp{make compare} may fail on version 5 of IRIX unless you add
@option{-save-temps} to @code{CFLAGS}.  On these systems, the name of the
assembler input file is stored in the object file, and that makes
comparison fail if it differs between the @code{stage1} and
@code{stage2} compilations.  The option @option{-save-temps} forces a
fixed name to be used for the assembler input file, instead of a
randomly chosen name in @file{/tmp}.  Do not add @option{-save-temps}
unless the comparisons fail without that option.  If you do you
@option{-save-temps}, you will have to manually delete the @samp{.i} and
@samp{.s} files after each series of compilations.

If you use the MIPS C compiler to bootstrap, it may be necessary
to increase its table size for switch statements with the
@option{-Wf,-XNg1500} option.  If you use the @option{-O2}
optimization option, you also need to use @option{-Olimit 3000}.

To enable debugging under IRIX 5, you must use GNU @command{as} 2.11.2
or later,
and use the @option{--with-gnu-as} configure option when configuring GCC.
GNU @command{as} is distributed as part of the binutils package.
When using release 2.11.2, you need to apply a patch
@uref{http://sources.redhat.com/ml/binutils/2001-07/msg00352.html,,http://sources.redhat.com/ml/binutils/2001-07/msg00352.html}
which will be included in the next release of binutils.

When building GCC, the build process loops rebuilding @command{cc1} over
and over again.  This happens on @samp{mips-sgi-irix5.2}, and possibly
other platforms.  It has been reported that this is a known bug in the
@command{make} shipped with IRIX 5.2.  We recommend you use GNU
@command{make} instead of the vendor supplied @command{make} program;
however, you may have success with @command{smake} on IRIX 5.2 if you do
not have GNU @command{make} available.

@html
<hr />
@end html
@heading @anchor{mips-sgi-irix6}mips-sgi-irix6

If you are using IRIX @command{cc} as your bootstrap compiler, you must
ensure that the N32 ABI is in use.  To test this, compile a simple C
file with @command{cc} and then run @command{file} on the
resulting object file.  The output should look like:

@example
test.o: ELF N32 MSB @dots{}
@end example

If you see:

@example
test.o: ELF 32-bit MSB @dots{}
@end example

or

@example
test.o: ELF 64-bit MSB @dots{}
@end example

then your version of @command{cc} uses the O32 or N64 ABI by default.  You
should set the environment variable @env{CC} to @samp{cc -n32}
before configuring GCC@.

If you want the resulting @command{gcc} to run on old 32-bit systems
with the MIPS R4400 CPU, you need to ensure that only code for the mips3
instruction set architecture (ISA) is generated.  While GCC 3.x does
this correctly, both GCC 2.95 and SGI's MIPSpro @command{cc} may change
the ISA depending on the machine where GCC is built.  Using one of them
as the bootstrap compiler may result in mips4 code, which won't run at
all on mips3-only systems.  For the test program above, you should see:

@example
test.o: ELF N32 MSB mips-3 @dots{}
@end example

If you get:

@example
test.o: ELF N32 MSB mips-4 @dots{}
@end example

instead, you should set the environment variable @env{CC} to @samp{cc
-n32 -mips3} or @samp{gcc -mips3} respectively before configuring GCC@.

GCC on IRIX 6 is usually built to support both the N32 and N64 ABIs.  If
you build GCC on a system that doesn't have the N64 libraries installed,
you need to configure with @option{--disable-multilib} so GCC doesn't
try to use them.  Look for @file{/usr/lib64/libc.so.1} to see if you
have the 64-bit libraries installed.

You must @emph{not} use GNU @command{as} (which isn't built anyway as of
binutils 2.11.2) on IRIX 6 platforms; doing so will only cause problems.

GCC does not currently support generating O32 ABI binaries in the
@samp{mips-sgi-irix6} configurations.  It is possible to create a GCC
with O32 ABI only support by configuring it for the @samp{mips-sgi-irix5}
target and using a patched GNU @command{as} 2.11.2 as documented in the
@uref{#mips-sgi-irix5,,@samp{mips-sgi-irix5}} section above.  Using the
native assembler requires patches to GCC which will be included in a
future release.  It is
expected that O32 ABI support will be available again in a future release.

The @option{--enable-threads} option doesn't currently work, a patch is
in preparation for a future release.  The @option{--enable-libgcj}
option is disabled by default: IRIX 6 uses a very low default limit
(20480) for the command line length.  Although libtool contains a
workaround for this problem, at least the N64 @samp{libgcj} is known not
to build despite this, running into an internal error of the native
@command{ld}.  A sure fix is to increase this limit (@samp{ncargs}) to
its maximum of 262144 bytes.  If you have root access, you can use the
@command{systune} command to do this.

GCC does not correctly pass/return structures which are
smaller than 16 bytes and which are not 8 bytes.  The problem is very
involved and difficult to fix.  It affects a number of other targets also,
but IRIX 6 is affected the most, because it is a 64-bit target, and 4 byte
structures are common.  The exact problem is that structures are being padded
at the wrong end, e.g.@: a 4 byte structure is loaded into the lower 4 bytes
of the register when it should be loaded into the upper 4 bytes of the
register.

GCC is consistent with itself, but not consistent with the SGI C compiler
(and the SGI supplied runtime libraries), so the only failures that can
happen are when there are library functions that take/return such
structures. There are very few such library functions.  Currently this
is known to affect @code{inet_ntoa}, @code{inet_lnaof},
@code{inet_netof}, @code{inet_makeaddr}, and @code{semctl}.  Until the
bug is fixed, GCC contains workarounds for the known affected functions.

See @uref{http://freeware.sgi.com/,,http://freeware.sgi.com/} for more
information about using GCC on IRIX platforms.

@html
<hr />
@end html
@heading @anchor{powerpc*-*-*}powerpc-*-*

You can specify a default version for the @option{-mcpu=@var{cpu_type}}
switch by using the configure option @option{--with-cpu-@var{cpu_type}}.

@html
<hr />
@end html
@heading @anchor{powerpc-*-darwin*}powerpc-*-darwin*
PowerPC running Darwin (Mac OS X kernel).

Pre-installed versions of Mac OS X may not include any developer tools,
meaning that you will not be able to build GCC from source.  Tool
binaries are available at
@uref{http://developer.apple.com/tools/compilers.html} (free
registration required).

The default stack limit of 512K is too small, which may cause compiles
to fail with 'Bus error'.  Set the stack larger, for instance
by doing @samp{limit stack 800}.  It's a good idea to use the GNU
preprocessor instead of Apple's @file{cpp-precomp} during the first stage of
bootstrapping; this is automatic when doing @samp{make bootstrap}, but
to do it from the toplevel objdir you will need to say @samp{make
CC='cc -no-cpp-precomp' bootstrap}.

The version of GCC shipped by Apple typically includes a number of
extensions not available in a standard GCC release.  These extensions
are generally specific to Mac programming.

@html
<hr />
@end html
@heading @anchor{powerpc-*-elf}powerpc-*-elf, powerpc-*-sysv4
PowerPC system in big endian mode, running System V.4.

@html
<hr />
@end html
@heading @anchor{powerpc-*-linux-gnu*}powerpc-*-linux-gnu*

You will need
@uref{ftp://ftp.kernel.org/pub/linux/devel/binutils,,binutils 2.13.90.0.10}
or newer for a working GCC@.

@html
<hr />
@end html
@heading @anchor{powerpc-*-netbsd*}powerpc-*-netbsd*
PowerPC system in big endian mode running NetBSD@.  To build the
documentation you will need Texinfo version 4.2 (NetBSD 1.5.1 included
Texinfo version 3.12).

@html
<hr />
@end html
@heading @anchor{powerpc-*-eabisim}powerpc-*-eabisim
Embedded PowerPC system in big endian mode for use in running under the
PSIM simulator.

@html
<hr />
@end html
@heading @anchor{powerpc-*-eabi}powerpc-*-eabi
Embedded PowerPC system in big endian mode.

@html
<hr />
@end html
@heading @anchor{powerpcle-*-elf}powerpcle-*-elf, powerpcle-*-sysv4
PowerPC system in little endian mode, running System V.4.

@html
<hr />
@end html
@heading @anchor{powerpcle-*-eabisim}powerpcle-*-eabisim
Embedded PowerPC system in little endian mode for use in running under
the PSIM simulator.

@html
<hr />
@end html
@heading @anchor{powerpcle-*-eabi}powerpcle-*-eabi
Embedded PowerPC system in little endian mode.

@html
<hr />
@end html
@heading @anchor{s390-*-linux*}s390-*-linux*
S/390 system running Linux for S/390@.

@html
<hr />
@end html
@heading @anchor{s390x-*-linux*}s390x-*-linux*
zSeries system (64-bit) running Linux for zSeries@.

@html
<hr />
@end html
@heading @anchor{s390x-ibm-tpf*}s390x-ibm-tpf*
zSeries system (64-bit) running TPF.  This platform is 
supported as cross-compilation target only.

@html
<hr />
@end html
@c Please use Solaris 2 to refer to all release of Solaris, starting
@c with 2.0 until 2.6, 7, and 8.  Solaris 1 was a marketing name for
@c SunOS 4 releases which we don't use to avoid confusion.  Solaris
@c alone is too unspecific and must be avoided.
@heading @anchor{*-*-solaris2*}*-*-solaris2*

Sun does not ship a C compiler with Solaris 2.  To bootstrap and install
GCC you first have to install a pre-built compiler, see our
@uref{binaries.html,,binaries page} for details.

The Solaris 2 @command{/bin/sh} will often fail to configure
@file{libstdc++-v3}, @file{boehm-gc} or @file{libjava}.  We therefore
recommend to use the following sequence of commands to bootstrap and
install GCC:

@smallexample
   % CONFIG_SHELL=/bin/ksh
   % export CONFIG_SHELL
@end smallexample

and then proceed as described in @uref{build.html,,the build instructions},
where we strongly recommend using GNU make and specifying an absolute path
to invoke @var{srcdir}/configure.

Solaris 2 comes with a number of optional OS packages.  Some of these
are needed to use GCC fully, namely @code{SUNWarc},
@code{SUNWbtool}, @code{SUNWesu}, @code{SUNWhea}, @code{SUNWlibm},
@code{SUNWsprot}, and @code{SUNWtoo}.  If you did not install all
optional packages when installing Solaris 2, you will need to verify that
the packages that GCC needs are installed.

To check whether an optional package is installed, use
the @command{pkginfo} command.  To add an optional package, use the
@command{pkgadd} command.  For further details, see the Solaris 2
documentation.

Trying to use the linker and other tools in
@file{/usr/ucb} to install GCC has been observed to cause trouble.
For example, the linker may hang indefinitely.  The fix is to remove
@file{/usr/ucb} from your @env{PATH}.

The build process works more smoothly with the legacy Sun tools so, if you
have @file{/usr/xpg4/bin} in your @env{PATH}, we recommend that you place
@file{/usr/bin} before @file{/usr/xpg4/bin} for the duration of the build.

All releases of GNU binutils prior to 2.11.2 have known bugs on this
platform.  We recommend the use of GNU binutils 2.11.2 or the vendor
tools (Sun @command{as}, Sun @command{ld}).

Sun bug 4296832 turns up when compiling X11 headers with GCC 2.95 or
newer: @command{g++} will complain that types are missing.  These headers assume
that omitting the type means @code{int}; this assumption worked for C89 but
is wrong for C++, and is now wrong for C99 also.

@command{g++} accepts such (invalid) constructs with the option
@option{-fpermissive}; it
will assume that any missing type is @code{int} (as defined by C89).

There are patches for Solaris 2.6 (105633-56 or newer for SPARC,
106248-42 or newer for Intel), Solaris 7 (108376-21 or newer for SPARC,
108377-20 for Intel), and Solaris 8 (108652-24 or newer for SPARC,
108653-22 for Intel) that fix this bug.

@html
<hr />
@end html
@heading @anchor{sparc-sun-solaris2*}sparc-sun-solaris2*

When GCC is configured to use binutils 2.11.2 or later the binaries
produced are smaller than the ones produced using Sun's native tools;
this difference is quite significant for binaries containing debugging
information.

Sun @command{as} 4.x is broken in that it cannot cope with long symbol names.
A typical error message might look similar to the following:

@smallexample
/usr/ccs/bin/as: "/var/tmp/ccMsw135.s", line 11041: error:
  can't compute value of an expression involving an external symbol.
@end smallexample

This is Sun bug 4237974.  This is fixed with patch 108908-02 for Solaris
2.6 and has been fixed in later (5.x) versions of the assembler,
starting with Solaris 7.

Starting with Solaris 7, the operating system is capable of executing
64-bit SPARC V9 binaries.  GCC 3.1 and later properly supports
this; the @option{-m64} option enables 64-bit code generation.
However, if all you want is code tuned for the UltraSPARC CPU, you
should try the @option{-mtune=ultrasparc} option instead, which produces
code that, unlike full 64-bit code, can still run on non-UltraSPARC
machines.

When configuring on a Solaris 7 or later system that is running a kernel
that supports only 32-bit binaries, one must configure with
@option{--disable-multilib}, since we will not be able to build the
64-bit target libraries.

@html
<hr />
@end html
@heading @anchor{sparc-sun-solaris2.7}sparc-sun-solaris2.7

Sun patch 107058-01 (1999-01-13) for Solaris 7/SPARC triggers a bug in
the dynamic linker.  This problem (Sun bug 4210064) affects GCC 2.8
and later, including all EGCS releases.  Sun formerly recommended
107058-01 for all Solaris 7 users, but around 1999-09-01 it started to
recommend it only for people who use Sun's compilers.

Here are some workarounds to this problem:
@itemize @bullet
@item
Do not install Sun patch 107058-01 until after Sun releases a
complete patch for bug 4210064.  This is the simplest course to take,
unless you must also use Sun's C compiler.  Unfortunately 107058-01
is preinstalled on some new Solaris 7-based hosts, so you may have to
back it out.

@item
Copy the original, unpatched Solaris 7
@command{/usr/ccs/bin/as} into
@command{/usr/local/libexec/gcc/sparc-sun-solaris2.7/3.4/as},
adjusting the latter name to fit your local conventions and software
version numbers.

@item
Install Sun patch 106950-03 (1999-05-25) or later.  Nobody with
both 107058-01 and 106950-03 installed has reported the bug with GCC
and Sun's dynamic linker.  This last course of action is riskiest,
for two reasons.  First, you must install 106950 on all hosts that
run code generated by GCC; it doesn't suffice to install it only on
the hosts that run GCC itself.  Second, Sun says that 106950-03 is
only a partial fix for bug 4210064, but Sun doesn't know whether the
partial fix is adequate for GCC@.  Revision -08 or later should fix
the bug.  The current (as of 2001-09-24) revision is -14, and is included in
the Solaris 7 Recommended Patch Cluster.
@end itemize

GCC 3.3 triggers a bug in version 5.0 Alpha 03/27/98 of the Sun assembler,
which causes a bootstrap failure when linking the 64-bit shared version of
libgcc. A typical error message is:

@smallexample
ld: fatal: relocation error: R_SPARC_32: file libgcc/sparcv9/_muldi3.o:
  symbol <unknown>:  offset 0xffffffff7ec133e7 is non-aligned.
@end smallexample

This bug has been fixed in the final 5.0 version of the assembler.

@html
<hr />
@end html
@heading @anchor{sparc-*-linux*}sparc-*-linux*

GCC versions 3.0 and higher require binutils 2.11.2 and glibc 2.2.4
or newer on this platform.  All earlier binutils and glibc
releases mishandled unaligned relocations on @code{sparc-*-*} targets.


@html
<hr />
@end html
@heading @anchor{sparc64-*-solaris2*}sparc64-*-solaris2*

The following compiler flags must be specified in the configure
step in order to bootstrap this target with the Sun compiler:

@example
   % CC="cc -xildoff -xarch=v9" @var{srcdir}/configure [@var{options}] [@var{target}]
@end example

@option{-xildoff} turns off the incremental linker, and @option{-xarch=v9}
specifies the SPARC-V9 architecture to the Sun linker and assembler.

@html
<hr />
@end html
@heading @anchor{sparcv9-*-solaris2*}sparcv9-*-solaris2*

This is a synonym for sparc64-*-solaris2*.

@html
<hr />
@end html
@heading @anchor{#*-*-sysv*}*-*-sysv*
On System V release 3, you may get this error message
while linking:

@smallexample
ld fatal: failed to write symbol name @var{something}
 in strings table for file @var{whatever}
@end smallexample

This probably indicates that the disk is full or your ulimit won't allow
the file to be as large as it needs to be.

This problem can also result because the kernel parameter @code{MAXUMEM}
is too small.  If so, you must regenerate the kernel and make the value
much larger.  The default value is reported to be 1024; a value of 32768
is said to work.  Smaller values may also work.

On System V, if you get an error like this,

@example
/usr/local/lib/bison.simple: In function `yyparse':
/usr/local/lib/bison.simple:625: virtual memory exhausted
@end example

@noindent
that too indicates a problem with disk space, ulimit, or @code{MAXUMEM}.

On a System V release 4 system, make sure @file{/usr/bin} precedes
@file{/usr/ucb} in @code{PATH}.  The @command{cc} command in
@file{/usr/ucb} uses libraries which have bugs.

@html
<hr />
@end html
@heading @anchor{vax-dec-ultrix}vax-dec-ultrix
Don't try compiling with VAX C (@command{vcc}).  It produces incorrect code
in some cases (for example, when @code{alloca} is used).

@html
<hr />
@end html
@heading @anchor{*-*-vxworks*}*-*-vxworks*
Support for VxWorks is in flux.  At present GCC supports @emph{only} the
very recent VxWorks 5.5 (aka Tornado 2.2) release, and only on PowerPC.
We welcome patches for other architectures supported by VxWorks 5.5.
Support for VxWorks AE would also be welcome; we believe this is merely
a matter of writing an appropriate ``configlette'' (see below).  We are
not interested in supporting older, a.out or COFF-based, versions of
VxWorks in GCC 3.

VxWorks comes with an older version of GCC installed in
@file{@var{$WIND_BASE}/host}; we recommend you do not overwrite it.
Choose an installation @var{prefix} entirely outside @var{$WIND_BASE}.
Before running @command{configure}, create the directories @file{@var{prefix}}
and @file{@var{prefix}/bin}.  Link or copy the appropriate assembler,
linker, etc. into @file{@var{prefix}/bin}, and set your @var{PATH} to
include that directory while running both @command{configure} and
@command{make}.

You must give @command{configure} the
@option{--with-headers=@var{$WIND_BASE}/target/h} switch so that it can
find the VxWorks system headers.  Since VxWorks is a cross compilation
target only, you must also specify @option{--target=@var{target}}.
@command{configure} will attempt to create the directory
@file{@var{prefix}/@var{target}/sys-include} and copy files into it;
make sure the user running @command{configure} has sufficient privilege
to do so.

GCC's exception handling runtime requires a special ``configlette''
module, @file{contrib/gthr_supp_vxw_5x.c}.  Follow the instructions in
that file to add the module to your kernel build.  (Future versions of
VxWorks will incorporate this module.)  

@html
<hr />
@end html
@heading @anchor{xtensa-*-elf}xtensa-*-elf

This target is intended for embedded Xtensa systems using the
@samp{newlib} C library.  It uses ELF but does not support shared
objects.  Designed-defined instructions specified via the
Tensilica Instruction Extension (TIE) language are only supported
through inline assembly.

The Xtensa configuration information must be specified prior to
building GCC@.  The @file{include/xtensa-config.h} header
file contains the configuration information.  If you created your
own Xtensa configuration with the Xtensa Processor Generator, the
downloaded files include a customized copy of this header file,
which you can use to replace the default header file.

@html
<hr />
@end html
@heading @anchor{xtensa-*-linux*}xtensa-*-linux*

This target is for Xtensa systems running GNU/Linux.  It supports ELF
shared objects and the GNU C library (glibc).  It also generates
position-independent code (PIC) regardless of whether the
@option{-fpic} or @option{-fPIC} options are used.  In other
respects, this target is the same as the
@uref{#xtensa-*-elf,,@samp{xtensa-*-elf}} target.

@html
<hr />
@end html
@heading @anchor{windows}Microsoft Windows (32-bit)

A port of GCC 2.95.2 and 3.x is included with the
@uref{http://www.cygwin.com/,,Cygwin environment}.

Current (as of early 2001) snapshots of GCC will build under Cygwin
without modification.

GCC does not currently build with Microsoft's C++ compiler and there
are no plans to make it do so.

@html
<hr />
@end html
@heading @anchor{os2}OS/2

GCC does not currently support OS/2.  However, Andrew Zabolotny has been
working on a generic OS/2 port with pgcc.  The current code can be found
at @uref{http://www.goof.com/pcg/os2/,,http://www.goof.com/pcg/os2/}.

An older copy of GCC 2.8.1 is included with the EMX tools available at
@uref{ftp://ftp.leo.org/pub/comp/os/os2/leo/devtools/emx+gcc/,,
ftp://ftp.leo.org/pub/comp/os/os2/leo/devtools/emx+gcc/}.

@html
<hr />
@end html
@heading @anchor{older}Older systems

GCC contains support files for many older (1980s and early
1990s) Unix variants.  For the most part, support for these systems
has not been deliberately removed, but it has not been maintained for
several years and may suffer from bitrot.

Starting with GCC 3.1, each release has a list of ``obsoleted'' systems.
Support for these systems is still present in that release, but
@command{configure} will fail unless the @option{--enable-obsolete}
option is given.  Unless a maintainer steps forward, support for these
systems will be removed from the next release of GCC@.

Support for old systems as hosts for GCC can cause problems if the
workarounds for compiler, library and operating system bugs affect the
cleanliness or maintainability of the rest of GCC@.  In some cases, to
bring GCC up on such a system, if still possible with current GCC, may
require first installing an old version of GCC which did work on that
system, and using it to compile a more recent GCC, to avoid bugs in the
vendor compiler.  Old releases of GCC 1 and GCC 2 are available in the
@file{old-releases} directory on the @uref{../mirrors.html,,GCC mirror
sites}.  Header bugs may generally be avoided using
@command{fixincludes}, but bugs or deficiencies in libraries and the
operating system may still cause problems.

Support for older systems as targets for cross-compilation is less
problematic than support for them as hosts for GCC; if an enthusiast
wishes to make such a target work again (including resurrecting any of
the targets that never worked with GCC 2, starting from the last CVS
version before they were removed), patches
@uref{../contribute.html,,following the usual requirements} would be
likely to be accepted, since they should not affect the support for more
modern targets.

For some systems, old versions of GNU binutils may also be useful,
and are available from @file{pub/binutils/old-releases} on
@uref{http://sources.redhat.com/mirrors.html,,sources.redhat.com mirror sites}.

Some of the information on specific systems above relates to
such older systems, but much of the information
about GCC on such systems (which may no longer be applicable to
current GCC) is to be found in the GCC texinfo manual.

@html
<hr />
@end html
@heading @anchor{elf_targets}all ELF targets (SVR4, Solaris 2, etc.)

C++ support is significantly better on ELF targets if you use the
@uref{./configure.html#with-gnu-ld,,GNU linker}; duplicate copies of
inlines, vtables and template instantiations will be discarded
automatically.


@html
<hr />
<p>
@end html
@ifhtml
@uref{./index.html,,Return to the GCC Installation page}
@end ifhtml
@end ifset

@c ***Old documentation******************************************************
@ifset oldhtml
@include install-old.texi
@html
<hr />
<p>
@end html
@ifhtml
@uref{./index.html,,Return to the GCC Installation page}
@end ifhtml
@end ifset

@c ***GFDL********************************************************************
@ifset gfdlhtml
@include fdl.texi
@html
<hr />
<p>
@end html
@ifhtml
@uref{./index.html,,Return to the GCC Installation page}
@end ifhtml
@end ifset

@c ***************************************************************************
@c Part 6 The End of the Document
@ifinfo
@comment node-name,     next,          previous, up
@node    Concept Index, , GNU Free Documentation License, Top
@end ifinfo

@ifinfo
@unnumbered Concept Index

@printindex cp

@contents
@end ifinfo
@bye