2006-12-19 Paolo Bonzini <bonzini@gnu.org>
* configure.texi: Fix botched commit.
This commit is contained in:
Paolo Bonzini
@@ -1,3 +1,7 @@
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2006-12-19 Paolo Bonzini <bonzini@gnu.org>
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* configure.texi: Fix botched commit.
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2006-05-31 Daniel Jacobowitz <dan@codesourcery.com>
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* texi2pod.pl: Correct handling of absolute @include.
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@@ -300,6 +300,12 @@ machine dependent files such as executables.
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The default for @samp{--prefix} is @file{/usr/local}. The default for
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@samp{--exec-prefix} is the value used for @samp{--prefix}.
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The convention used in Cygnus releases is to use a @samp{--prefix}
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option of @file{/usr/cygnus/@var{release}}, where @var{release} is the
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name of the release, and to use a @samp{--exec-prefix} option of
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@file{/usr/cygnus/@var{release}/H-@var{host}}, where @var{host} is the
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configuration name of the host system (@pxref{Configuration Names}).
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Do not use either the source or the object directory as the installation
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directory. That will just lead to confusion.
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@@ -1670,9 +1676,12 @@ the autoconf documentation for @samp{AC_ARG_PROGRAM}.
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@section Cross Tools in the Cygnus Tree
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The Cygnus tree is used for various packages including gdb, the GNU
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binutils, and egcs. In the Cygnus tree, the top level @file{Makefile.in}
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binutils, and egcs. It is also, of course, used for Cygnus releases.
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In the Cygnus tree, the top level @file{configure} script uses the old
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Cygnus configure system, not autoconf. The top level @file{Makefile.in}
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is written to build packages based on what is in the source tree, and
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supports building and bootstrapping a large number of tools in a single
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supports building a large number of tools in a single
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@samp{configure}/@samp{make} step.
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The Cygnus tree may be configured with a @samp{--target} option. The
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@@ -2123,26 +2132,27 @@ lines with a trailing backslash as a continuation character).
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@example
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mkdir linux-x-cygwin32
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cd linux-x-cygwin32
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@var{srcdir}/configure --target i386-cygwin32 --prefix=@var{installdir}
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@var{srcdir}/configure --target i386-cygwin32 --prefix=@var{installdir} \
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--exec-prefix=@var{installdir}/H-i386-linux
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make
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make install
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cd ..
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mkdir linux-x-mips-elf
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cd linux-x-mips-elf
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@var{srcdir}/configure --target mips-elf --prefix=@var{installdir}
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@var{srcdir}/configure --target mips-elf --prefix=@var{installdir} \
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--exec-prefix=@var{installdir}/H-i386-linux
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make
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make install
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cd ..
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mkdir cygwin32-x-mips-elf
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cd cygwin32-x-mips-elf
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@var{srcdir}/configure --build=i386-linux-gnu --host=i386-cygwin32 \
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--target=mips-elf --prefix=@var{wininstalldir}
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--target=mips-elf --prefix=@var{wininstalldir} \
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--exec-prefix=@var{wininstalldir}/H-i386-cygwin32
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make
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make install
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@end example
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Note that we specify a different prefix in the last build, because this
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does not contain Linux executables, but rather Windows executables.
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You would then copy the contents of @var{wininstalldir} over to the
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Windows machine, and run the resulting programs.
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@@ -2253,63 +2263,152 @@ crucial.
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The gcc @file{Makefile.in} shows a complex situation in which certain
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files, such as @file{rtl.c}, must be compiled into both subsidiary
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programs run on the build system and into the final program. This
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approach may be of interest for advanced build system hackers.
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approach may be of interest for advanced build system hackers. Note
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that the build system compiler is rather confusingly called
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@samp{HOST_CC}.
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@node Top level Configure
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@chapter Top level Configure
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@cindex top level configure
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@node Cygnus Configure
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@chapter Cygnus Configure
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@cindex cygnus configure
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The top level configure script detects the tools that are used in the
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Cygnus tree. This script is a rewrite of the Cygnus configure script,
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which predated autoconf.
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The Cygnus configure script predates autoconf. All of its interesting
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features have been incorporated into autoconf. No new programs should
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be written to use the Cygnus configure script.
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The script includes all the logic to detect the host and target tools,
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and to customize the @file{Makefile} to support the special needs of
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some systems.
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However, the Cygnus configure script is still used in a few places: at
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the top of the Cygnus tree and in a few target libraries in the Cygnus
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tree. Until those uses have been replaced with autoconf, some brief
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notes are appropriate here. This is not complete documentation, but it
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should be possible to use this as a guide while examining the scripts
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themselves.
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A particularly delicate point is finding the target tools--these include
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the assembler, the linker, and the other @command{binutils} such as
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@command{nm} or @command{ar}. Some of these need to be invoked by GCC;
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others, such as @command{objdump}, are necessary during configuration, in
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order to detect the set of features supported by the assembler and linker.
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@menu
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* Cygnus Configure Basics:: Cygnus Configure Basics.
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* Cygnus Configure in C++ Libraries:: Cygnus Configure in C++ Libraries.
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@end menu
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In general, the top level configure tries to follow these lines in order
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to detect the target tools:
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@node Cygnus Configure Basics
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@section Cygnus Configure Basics
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@table @itemize
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@item try to detect a consistent set of tools
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Cygnus configure does not use any generated files; there is no program
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corresponding to @samp{autoconf}. Instead, there is a single shell
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script named @samp{configure} which may be found at the top of the
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Cygnus tree. This shell script was written by hand; it was not
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generated by autoconf, and it is incorrect, and indeed harmful, to run
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@samp{autoconf} in the top level of a Cygnus tree.
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@item try to detect the same tools that the installed GCC will use
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@end table
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Cygnus configure works in a particular directory by examining the file
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@file{configure.in} in that directory. That file is broken into four
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separate shell scripts.
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To achieve the first goal, we use the same search criterion for all tools,
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even those that the compiler never invokes.
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The first is the contents of @file{configure.in} up to a line that
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starts with @samp{# per-host:}. This is the common part.
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To achieve the second goal when the @samp{build} and @samp{host} systems
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are the same, we search the same directories that the installed compiler
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will search. This is overridden if the assembler and linker are being
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compiled together with GCC, because after installation GCC
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will find the tools that were just compiled.
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The second is the rest of @file{configure.in} up to a line that starts
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with @samp{# per-target:}. This is the per host part.
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To achieve the second goal when cross compiling (the @samp{build} and
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the @samp{host} systems are different, we ask the installed GCC for the
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name of the tool it uses. This is because the only good choice for a
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compiler is the same GCC version that is being installed (@pxref{Cross
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Cygnus CCross: Building a Cross Program}), and we assume that on the
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host system we'll have not only the same GCC version, but also the same
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binutils version.
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The third is the rest of @file{configure.in} up to a line that starts
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with @samp{# post-target:}. This is the per target part.
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The location of the target tools can also be specified using the
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@option{--with-build-time-tools} option to the top level configure
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The fourth is the remainder of @file{configure.in}. This is the post
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target part.
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If any of these comment lines are missing, the corresponding shell
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script is empty.
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Cygnus configure will first execute the common part. This must set the
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shell variable @samp{srctrigger} to the name of a source file, to
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confirm that Cygnus configure is looking at the right directory. This
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may set the shell variables @samp{package_makefile_frag} and
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@samp{package_makefile_rules_frag}.
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Cygnus configure will next set the @samp{build} and @samp{host} shell
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variables, and execute the per host part. This may set the shell
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variable @samp{host_makefile_frag}.
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Cygnus configure will next set the @samp{target} variable, and execute
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the per target part. This may set the shell variable
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@samp{target_makefile_frag}.
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Any of these scripts may set the @samp{subdirs} shell variable. This
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variable is a list of subdirectories where a @file{Makefile.in} file may
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be found. Cygnus configure will automatically look for a
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@file{Makefile.in} file in the current directory. The @samp{subdirs}
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shell variable is not normally used, and I believe that the only
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directory which uses it at present is @file{newlib}.
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For each @file{Makefile.in}, Cygnus configure will automatically create
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a @file{Makefile} by adding definitions for @samp{make} variables such
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as @samp{host} and @samp{target}, and automatically editing the values
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of @samp{make} variables such as @samp{prefix} if they are present.
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Also, if any of the @samp{makefile_frag} shell variables are set, Cygnus
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configure will interpret them as file names relative to either the
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working directory or the source directory, and will read the contents of
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the file into the generated @file{Makefile}. The file contents will be
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read in after the first line in @file{Makefile.in} which starts with
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@samp{####}.
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These @file{Makefile} fragments are used to customize behaviour for a
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particular host or target. They serve to select particular files to
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compile, and to define particular preprocessor macros by providing
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values for @samp{make} variables which are then used during compilation.
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Cygnus configure, unlike autoconf, normally does not do feature tests,
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and normally requires support to be added manually for each new host.
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The @file{Makefile} fragment support is similar to the autoconf
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@samp{AC_SUBST_FILE} macro.
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After creating each @file{Makefile}, the post target script will be run
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(i.e., it may be run several times). This script may further customize
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the @file{Makefile}. When it is run, the shell variable @samp{Makefile}
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will hold the name of the @file{Makefile}, including the appropriate
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directory component.
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Like an autoconf generated @file{configure} script, Cygnus configure
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will create a file named @file{config.status} which, when run, will
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automatically recreate the configuration. The @file{config.status} file
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will simply execute the Cygnus configure script again with the
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appropriate arguments.
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Any of the parts of @file{configure.in} may set the shell variables
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@samp{files} and @samp{links}. Cygnus configure will set up symlinks
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from the names in @samp{links} to the files named in @samp{files}. This
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is similar to the autoconf @samp{AC_LINK_FILES} macro.
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Finally, any of the parts of @file{configure.in} may set the shell
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variable @samp{configdirs} to a set of subdirectories. If it is set,
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Cygnus configure will recursively run the configure process in each
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subdirectory. If the subdirectory uses Cygnus configure, it will
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contain a @file{configure.in} file but no @file{configure} file, in
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which case Cygnus configure will invoke itself recursively. If the
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subdirectory has a @file{configure} file, Cygnus configure assumes that
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it is an autoconf generated @file{configure} script, and simply invokes
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it directly.
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@node Cygnus Configure in C++ Libraries
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@section Cygnus Configure in C++ Libraries
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@cindex @file{libstdc++} configure
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@cindex @file{libio} configure
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@cindex @file{libg++} configure
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The C++ library configure system, written by Per Bothner, deserves
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special mention. It uses Cygnus configure, but it does feature testing
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like that done by autoconf generated @file{configure} scripts. This
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approach is used in the libraries @file{libio}, @file{libstdc++}, and
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@file{libg++}.
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Most of the @file{Makefile} information is written out by the shell
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script @file{libio/config.shared}. Each @file{configure.in} file sets
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certain shell variables, and then invokes @file{config.shared} to create
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two package @file{Makefile} fragments. These fragments are then
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incorporated into the resulting @file{Makefile} by the Cygnus configure
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script.
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If no target-specific tools are found, the top level configure script
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will try to use the host tools if suitable.
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The script and the accompanying Makefile support building programs
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and libraries for either the build, the host or the target system.
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The target libraries, however, need to help in order to support
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@samp{multilibs}.
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The file @file{_G_config.h} is created in the @file{libio} object
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directory by running the shell script @file{libio/gen-params}. This
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shell script uses feature tests to define macros and typedefs in
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@file{_G_config.h}.
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@node Multilibs
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@chapter Multilibs
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@@ -2329,9 +2428,7 @@ called @dfn{multilibs}.
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Multilibs are not really part of the GNU configure and build system, but
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we discuss them here since they require support in the @file{configure}
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scripts and @file{Makefile}s used for target libraries. It is expected
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that in the future the toplevel will coordinate the building of the
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various multilibs, but this has not been implemented yet.
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scripts and @file{Makefile}s used for target libraries.
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@menu
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* Multilibs in gcc:: Multilibs in gcc.
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@@ -2479,16 +2576,17 @@ not defined by @samp{autoconf}. You may be using an old version of
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newly installled @samp{autoconf} is first on your @samp{PATH}. Also,
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see the next question.
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@cindex @samp{AM_GNU_GETTEXT} in @file{configure}
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@cindex @samp{CY_GNU_GETTEXT} in @file{configure}
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@cindex @samp{AM_PROG_LIBTOOL} in @file{configure}
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@item My @file{configure} script has stuff like @samp{AM_GNU_GETTEXT} in it.
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@item My @file{configure} script has stuff like @samp{CY_GNU_GETTEXT} in it.
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This means that you have macros in your @file{configure.in} which should
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be defined in your @file{aclocal.m4} file, but aren't. This usually
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means that @samp{aclocal} was not able to appropriate definitions of the
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macros. Make sure that you have installed all the packages you need.
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In particular, make sure that you have installed libtool (this is where
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@samp{AM_PROG_LIBTOOL} is defined) and gettext (this is where
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@samp{AM_GNU_GETTEXT} is defined).
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@samp{CY_GNU_GETTEXT} is defined, at least in the Cygnus version of
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gettext).
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@cindex @file{Makefile}, garbage characters
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@item My @file{Makefile} has @samp{@@} characters in it.
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@@ -2513,16 +2611,16 @@ regenerate all files (@file{Makefile}, @file{config.h}, etc.) based on
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the results of the configure script. The two cases are separate because
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it isn't always necessary to regenerate all the files after running
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@samp{config.status --recheck}. The @file{Makefile} targets generated
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by automake will use command-line arguments to only regenerate files
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as they are needed.
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by automake will use the environment variables @samp{CONFIG_FILES} and
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@samp{CONFIG_HEADERS} to only regenerate files as they are needed.
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@item What is the Cygnus tree?
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The Cygnus tree is used for various packages including gdb, the GNU
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binutils, and egcs. It is a derivative of the build system which was
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developed at Cygnus, using the Cygnus configure script. It permits
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building and bootstrapping many different packages with a single configure
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and make. The configure scripts in the tree have been converted to
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autoconf, but the general build structure remains intact.
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binutils, and egcs. It is also, of course, used for Cygnus releases.
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It is the build system which was developed at Cygnus, using the Cygnus
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configure script. It permits building many different packages with a
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single configure and make. The configure scripts in the tree are being
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converted to autoconf, but the general build structure remains intact.
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@item Why do I have to keep rebuilding and reinstalling the tools?
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I know, it's a pain. Unfortunately, there are bugs in the tools
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Reference in New Issue
Block a user