install.texi

理解和实践操作系统的一本好书

@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/Unix98 thread support.
@item posix95
Generic POSIX/Unix95 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.
@item nks
Novell Kernel Services thread support.
@end table

@item --enable-tls
Specify that the target supports TLS (Thread Local Storage).  Usually
configure can correctly determine if TLS is supported.  In cases where
it guesses incorrectly, TLS can be explicitly enabled or disabled with
@option{--enable-tls} or @option{--disable-tls}.  This can happen if
the assembler supports TLS but the C library does not, or if the
assumptions made by the configure test are incorrect.

@item --disable-tls
Specify that the target does not support TLS.
This is an alias for @option{--enable-tls=no}.

@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, M68k,
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-fpu=@var{type}
@itemx --with-float=@var{type}
These configure options provide default values for the @option{-mschedule=},
@option{-march=}, @option{-mtune=}, @option{-mabi=}, and @option{-mfpu=}
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 --with-mode=@var{mode}
Specify if the compiler should default to @option{-marm} or @option{-mthumb}.
This option is only supported on ARM targets.

@item --with-divide=@var{type}
Specify how the compiler should generate code for checking for
division by zero.  This option is only supported on the MIPS target.
The possibilities for @var{type} are:
@table @code
@item traps
Division by zero checks use conditional traps (this is the default on
systems that support conditional traps).
@item breaks
Division by zero checks use the break instruction.
@end table

@c If you make --with-llsc the default for additional targets,
@c update the --with-llsc description in the MIPS section below.

@item --with-llsc
On MIPS targets, make @option{-mllsc} the default when no
@option{-mno-lsc} option is passed.  This is the default for
Linux-based targets, as the kernel will emulate them if the ISA does
not provide them.

@item --without-llsc
On MIPS targets, make @option{-mno-llsc} the default when no
@option{-mllsc} option is passed.

@item --enable-__cxa_atexit
Define if you want to use __cxa_atexit, rather than atexit, to
register C++ destructors for local statics and global objects.
This is essential for fully standards-compliant handling of
destructors, but requires __cxa_atexit in libc.  This option is currently
only available on systems with GNU libc.  When enabled, this will cause
@option{-fuse-cxa-atexit} to be passed by default.

@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 --disable-bootstrap
For a native build, the default configuration is to perform
a 3-stage bootstrap of the compiler when @samp{make} is invoked,
testing that GCC can compile itself correctly.  If you want to disable
this process, you can configure with @option{--disable-bootstrap}.

@item --enable-bootstrap
In special cases, you may want to perform a 3-stage build
even if the target and host triplets are different.
This could happen when the host can run code compiled for
the target (e.g.@: host is i686-linux, target is i486-linux).
Starting from GCC 4.2, to do this you have to configure explicitly
with @option{--enable-bootstrap}.

@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 SVN development tree.  When building GCC from that development tree,
or from one of our snapshots, 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{libgfortran},
@samp{libjava}, @samp{libmudflap}, @samp{libstdc++}, and @samp{libobjc}.

@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:@*
@smallexample
grep language= */config-lang.in
@end smallexample
Currently, you can use any of the following:
@code{all}, @code{ada}, @code{c}, @code{c++}, @code{fortran}, @code{java},
@code{objc}, @code{obj-c++}, @code{treelang}.
Building the Ada compiler has special requirements, see below.
If you do not pass this flag, or specify the option @code{all}, then all
default languages available in the @file{gcc} sub-tree will be configured.
Ada, Objective-C++, and treelang are not default languages; the rest are.
Re-defining @code{LANGUAGES} when calling @samp{make} @strong{does not}
work anymore, as those language sub-directories might not have been
configured!

@item --enable-stage1-languages=@var{lang1},@var{lang2},@dots{}
Specify that a particular subset of compilers and their runtime
libraries should be built with the system C compiler during stage 1 of
the bootstrap process, rather than only in later stages with the
bootstrapped C compiler.  The list of valid values is the same as for
@option{--enable-languages}, and the option @code{all} will select all
of the languages enabled by @option{--enable-languages}.  This option is
primarily useful for GCC development; for instance, when a development
version of the compiler cannot bootstrap due to compiler bugs, or when
one is debugging front ends other than the C front end.  When this
option is used, one can then build the target libraries for the
specified languages with the stage-1 compiler by using @command{make
stage1-bubble all-target}, or run the testsuite on the stage-1 compiler
for the specified languages using @command{make stage1-start check-gcc}.

@item --disable-libada
Specify that the run-time libraries and tools used by GNAT should not
be built.  This can be useful for debugging, or for compatibility with
previous Ada build procedures, when it was required to explicitly
do a @samp{make -C gcc gnatlib_and_tools}.

@item --disable-libssp
Specify that the run-time libraries for stack smashing protection
should not be built.

@item --disable-libgomp
Specify that the run-time libraries used by GOMP should not be built.

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

@item --enable-targets=all
@itemx --enable-targets=@var{target_list}
Some GCC targets, e.g.@: powerpc64-linux, build bi-arch compilers.
These are compilers that are able to generate either 64-bit or 32-bit
code.  Typically, the corresponding 32-bit target, e.g.@:
powerpc-linux for powerpc64-linux, only generates 32-bit code.  This
option enables the 32-bit target to be a bi-arch compiler, which is
useful when you want a bi-arch compiler that defaults to 32-bit, and
you are building a bi-arch or multi-arch binutils in a combined tree.
Currently, this option only affects powerpc-linux and x86-linux.

@item --enable-secureplt
This option enables @option{-msecure-plt} by default for powerpc-linux.
@ifnothtml
@xref{RS/6000 and PowerPC Options,, RS/6000 and PowerPC Options, gcc,
Using the GNU Compiler Collection (GCC)},
@end ifnothtml
@ifhtml
See ``RS/6000 and PowerPC Options'' in the main manual
@end ifhtml

@item --enable-cld
This option enables @option{-mcld} by default for 32-bit x86 targets.
@ifnothtml
@xref{i386 and x86-64 Options,, i386 and x86-64 Options, gcc,
Using the GNU Compiler Collection (GCC)},
@end ifnothtml
@ifhtml
See ``i386 and x86-64 Options'' in the main manual
@end ifhtml

@item --enable-win32-registry
@itemx --enable-win32-registry=@var{key}
@itemx --disable-win32-registry
The @option{--enable-win32-registry} option enables Microsoft 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 internal
consistency checks of the requested complexity.  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 @samp{yes} by default when building
from SVN or snapshots, but @samp{release} for releases.  More control
over the checks may be had by specifying @var{list}.  The categories of
checks available are @samp{yes} (most common checks
@samp{assert,misc,tree,gc,rtlflag,runtime}), @samp{no} (no checks at
all), @samp{all} (all but @samp{valgrind}), @samp{release} (cheapest
checks @samp{assert,runtime}) or @samp{none} (same as @samp{no}).
Individual checks can be enabled with these flags @samp{assert},
@samp{df}, @samp{fold}, @samp{gc}, @samp{gcac} @samp{misc}, @samp{rtl},
@samp{rtlflag}, @samp{runtime}, @samp{tree}, and @samp{valgrind}.

The @samp{valgrind} check requires the external @command{valgrind}
simulator, available from @uref{http://valgrind.org/}.  The
@samp{df}, @samp{rtl}, @samp{gcac} and @samp{valgrind} checks are very expensive.
To disable all checking, @samp{--disable-checking} or
@samp{--enable-checking=none} must be explicitly requested.  Disabling
assertions will make the compiler and runtime slightly faster but
increase the risk of undetected internal errors causing wrong code to be
generated.

@item --enable-coverage
@itemx --enable-coverage=@var{level}
With this option, the compiler is built to collect self coverage