install.texi

gcc库的原代码,对编程有很大帮助.

@c Copyright (C) 1988, 1989, 1992, 1993, 1994, 1995 Free Software Foundation, Inc.
@c This is part of the GCC manual.
@c For copying conditions, see the file gcc.texi.

@c The text of this file appears in the file INSTALL
@c in the GCC distribution, as well as in the GCC manual.

@ifclear INSTALLONLY
@node Installation
@chapter Installing GNU CC
@end ifclear
@cindex installing GNU CC

@menu
* Configurations::    Configurations Supported by GNU CC.
* Other Dir::     Compiling in a separate directory (not where the source is).
* Cross-Compiler::   Building and installing a cross-compiler.
* Sun Install::   See below for installation on the Sun.
* VMS Install::   See below for installation on VMS.
* Collect2::	  How @code{collect2} works; how it finds @code{ld}.
* Header Dirs::   Understanding the standard header file directories.
@end menu

Here is the procedure for installing GNU CC on a Unix system.  See
@ref{VMS Install}, for VMS systems.  In this section we assume you
compile in the same directory that contains the source files; see
@ref{Other Dir}, to find out how to compile in a separate directory on Unix
systems.

You cannot install GNU C 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.

@enumerate
@item
If you have built GNU CC previously 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, it probably means that the directory is already suitably
clean.

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

@item
Specify the host, build and target machine configurations.  You do this
by running the file @file{configure}.

The @dfn{build} machine is the system which you are using, the
@dfn{host} machine is the system where you want to run the resulting
compiler (normally the build machine), and the @dfn{target} machine is
the system for which you want the compiler to generate code.

If you are building a compiler to produce code for the machine it runs
on (a native compiler), you normally do not need to specify any operands
to @file{configure}; it will try to guess the type of machine you are on
and use that as the build, host and target machines.  So you don't need
to specify a configuration when building a native compiler unless
@file{configure} cannot figure out what your configuration is or guesses
wrong.

In those cases, specify the build machine's @dfn{configuration name}
with the @samp{--build} option; the host and target will default to be
the same as the build machine.  (If you are building a cross-compiler,
see @ref{Cross-Compiler}.)

Here is an example:

@smallexample
./configure --build=sparc-sun-sunos4.1
@end smallexample

A configuration name may be canonical or it may be more or less
abbreviated.

A canonical configuration name has three parts, separated by dashes.
It looks like this: @samp{@var{cpu}-@var{company}-@var{system}}.
(The three parts may themselves contain dashes; @file{configure}
can figure out which dashes serve which purpose.)  For example,
@samp{m68k-sun-sunos4.1} specifies a Sun 3.

You can also replace parts of the configuration by nicknames or aliases.
For example, @samp{sun3} stands for @samp{m68k-sun}, so
@samp{sun3-sunos4.1} is another way to specify a Sun 3.  You can also
use simply @samp{sun3-sunos}, since the version of SunOS is assumed by
default to be version 4.  @samp{sun3-bsd} also works, since
@file{configure} knows that the only BSD variant on a Sun 3 is SunOS.

You can specify a version number after any of the system types, and some
of the CPU types.  In most cases, the version is irrelevant, and will be
ignored.  So you might as well specify the version if you know it.

See @ref{Configurations}, for a list of supported configuration names and
notes on many of the configurations.  You should check the notes in that
section before proceeding any further with the installation of GNU CC.

There are four additional options you can specify independently to 
describe variant hardware and software configurations.  These are
@samp{--with-gnu-as}, @samp{--with-gnu-ld}, @samp{--with-stabs} and
@samp{--nfp}.

@table @samp
@item --with-gnu-as
If you will use GNU CC with the GNU assembler (GAS), you should declare
this by using the @samp{--with-gnu-as} option when you run
@file{configure}.

Using this option does not install GAS.  It only modifies the output of
GNU CC to work with GAS.  Building and installing GAS is up to you.

Conversely, if you @emph{do not} wish to use GAS and do not specify
@samp{--with-gnu-as} when building GNU CC, it is up to you to make sure
that GAS is not installed.  GNU CC searches for a program named
@code{as} in various directories; if the program it finds is GAS, then
it runs GAS.  If you are not sure where GNU CC finds the assembler it is
using, try specifying @samp{-v} when you run it.

The systems where it makes a difference whether you use GAS are@*
@samp{hppa1.0-@var{any}-@var{any}}, @samp{hppa1.1-@var{any}-@var{any}},
@samp{i386-@var{any}-sysv}, @samp{i386-@var{any}-isc},@*
@samp{i860-@var{any}-bsd}, @samp{m68k-bull-sysv}, @samp{m68k-hp-hpux},
@samp{m68k-sony-bsd},@*
@samp{m68k-altos-sysv}, @samp{m68000-hp-hpux}, @samp{m68000-att-sysv},
@samp{@var{any}-lynx-lynxos}, and @samp{mips-@var{any}}).
On any other system, @samp{--with-gnu-as} has no effect.

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

@item --with-gnu-ld
Specify the option @samp{--with-gnu-ld} if you plan to use the GNU
linker with GNU CC.

This option does not cause the GNU linker to be installed; it just
modifies the behavior of GNU CC to work with the GNU linker.
Specifically, it inhibits the installation of @code{collect2}, a program
which otherwise serves as a front-end for the system's linker on most
configurations.

@item --with-stabs
On MIPS based systems and on Alphas, you must specify whether you want
GNU CC 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, GNU CC uses the ECOFF debugging format by default; if you
prefer BSD stabs, specify @samp{--with-stabs} when you configure GNU
CC.

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

@samp{--with-stabs} is meaningful on the ISC system on the 386, also, if
@samp{--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.

@samp{--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 --nfp
On certain systems, you must specify whether the machine has a floating
point unit.  These systems include @samp{m68k-sun-sunos@var{n}} and
@samp{m68k-isi-bsd}.  On any other system, @samp{--nfp} currently has no
effect, though perhaps there are other systems where it could usefully
make a difference.
@end table

The @file{configure} script searches subdirectories of the source
directory for other compilers that are to be integrated into GNU CC.
The GNU compiler for C++, called G++ is in a subdirectory named
@file{cp}.  @file{configure} inserts rules into @file{Makefile} to build
all of those compilers.

Here we spell out what files will be set up by @code{configure}.  Normally
you need not be concerned with these files.

@itemize @bullet
@item
@ifset INTERNALS
A file named @file{config.h} is created that contains a @samp{#include}
of the top-level config file for the machine you will run the compiler
on (@pxref{Config}).  This file is responsible for defining information
about the host machine.  It includes @file{tm.h}.
@end ifset
@ifclear INTERNALS
A file named @file{config.h} is created that contains a @samp{#include}
of the top-level config file for the machine you will run the compiler
on (@pxref{Config,,The Configuration File, gcc.info, Using and Porting
GCC}).  This file is responsible for defining information about the host
machine.  It includes @file{tm.h}.
@end ifclear

The top-level config file is located in the subdirectory @file{config}.
Its name is always @file{xm-@var{something}.h}; usually
@file{xm-@var{machine}.h}, but there are some exceptions.

If your system does not support symbolic links, you might want to
set up @file{config.h} to contain a @samp{#include} command which
refers to the appropriate file.

@item
A file named @file{tconfig.h} is created which includes the top-level config
file for your target machine.  This is used for compiling certain
programs to run on that machine.

@item
A file named @file{tm.h} is created which includes the
machine-description macro file for your target machine.  It should be in
the subdirectory @file{config} and its name is often
@file{@var{machine}.h}.

@item
The command file @file{configure} also constructs the file
@file{Makefile} by adding some text to the template file
@file{Makefile.in}.  The additional text comes from files in the
@file{config} directory, named @file{t-@var{target}} and
@file{x-@var{host}}.  If these files do not exist, it means nothing
needs to be added for a given target or host.
@end itemize

@item
The standard directory for installing GNU CC is @file{/usr/local/lib}.
If you want to install its files somewhere else, specify
@samp{--prefix=@var{dir}} when you run @file{configure}.  Here @var{dir}
is a directory name to use instead of @file{/usr/local} for all purposes
with one exception: the directory @file{/usr/local/include} is searched
for header files no matter where you install the compiler.  To override
this name, use the @code{--local-prefix} option below.

@item
Specify @samp{--local-prefix=@var{dir}} if you want the compiler to
search directory @file{@var{dir}/include} for locally installed header
files @emph{instead} of @file{/usr/local/include}.

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

@strong{Do not} specify @file{/usr} as the @samp{--local-prefix}!  The
directory you use for @samp{--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 @code{fixincludes} script.

@cindex Bison parser generator
@cindex parser generator, Bison
@item
Make sure the Bison parser generator is installed.  (This is
unnecessary if the Bison output files @file{c-parse.c} and
@file{cexp.c} are more recent than @file{c-parse.y} and @file{cexp.y}
and you do not plan to change the @samp{.y} files.)

Bison versions older than Sept 8, 1988 will produce incorrect output
for @file{c-parse.c}.

@item
If you have chosen a configuration for GNU CC which requires other GNU
tools (such as GAS or the GNU linker) instead of the standard system
tools, install the required tools in the build directory under the names
@file{as}, @file{ld} or whatever is appropriate.  This will enable the
compiler to find the proper tools for compilation of the program
@file{enquire}.

Alternatively, you can do subsequent compilation using a value of the
@code{PATH} environment variable such that the necessary GNU tools come
before the standard system tools.

@item
Build the compiler.  Just type @samp{make LANGUAGES=c} in the compiler
directory.

@samp{LANGUAGES=c} specifies that only the C compiler should be
compiled.  The makefile normally builds compilers for all the supported
languages; currently, C, C++ and Objective C.  However, C is the only
language that is sure to work when you build with other non-GNU C
compilers.  In addition, building anything but C at this stage is a
waste of time.

In general, you can specify the languages to build by typing the
argument @samp{LANGUAGES="@var{list}"}, where @var{list} is one or more
words from the list @samp{c}, @samp{c++}, and @samp{objective-c}.  If
you have any additional GNU compilers as subdirectories of the GNU CC
source directory, you may also specify their names in this list.

Ignore any warnings you may see about ``statement not reached'' in
@file{insn-emit.c}; they are normal.  Also, warnings about ``unknown
escape sequence'' are normal in @file{genopinit.c} and perhaps some
other files.  Likewise, you should ignore warnings about ``constant is
so large that it is unsigned'' in @file{insn-emit.c} and
@file{insn-recog.c} and a warning about a comparison always being zero
in @file{enquire.o}.  Any other compilation errors may represent bugs in
the port to your machine or operating system, and
@ifclear INSTALLONLY
should be investigated and reported (@pxref{Bugs}).
@end ifclear
@ifset INSTALLONLY
should be investigated and reported.
@end ifset

Some commercial compilers fail to compile GNU CC because they have bugs
or limitations.  For example, the Microsoft compiler is said to run out
of macro space.  Some Ultrix compilers run out of expression space; then
you need to break up the statement where the problem happens.

@item
If you are building a cross-compiler, stop here.  @xref{Cross-Compiler}.

@cindex stage1
@item
Move the first-stage object files and executables into a subdirectory
with this command:

@smallexample
make stage1