Bump to autoconf 2.69 and automake 1.15.1

When trying to run the update-gnulib.sh script in gdb, I get this:

Error: Wrong automake version (Unescaped left brace in regex is deprecated, passed through in regex; marked by <-- HERE in m/\${ <-- HERE ([^      =:+{}]+)}/ at /opt/automake/1.11.1/bin/automake line 4113.), we need 1.11.1.
Aborting.

Apparently, it's an issue with a regex in automake that triggers a
warning starting with Perl 5.22.  It has been fixed in automake 1.15.1.
So I think it's a good excuse to bump the versions of autoconf and
automake used in the gnulib import.  And to avoid requiring multiple
builds of autoconf/automake, it was suggested that we bump the required
version of those tools for all binutils-gdb.

For autoconf, the 2.69 version is universally available, so it's an easy
choice.  For automake, different distros and distro versions have
different automake versions.  But 1.15.1 seems to be the most readily
available as a package.  In any case, it's easy to build it from source.

I removed the version checks from AUTOMAKE_OPTIONS and AC_PREREQ,
because I don't think they are useful in our case.  They only specify a
lower bound for the acceptable version of automake/autoconf.  That's
useful if you let the user choose the version of the tool they want to
use, but want to set a minimum version (because you use a feature that
was introduced in that version).  In our case, we force people to use a
specific version anyway.  For the autoconf version, we have the check in
config/override.m4 that enforces the version we want.  It will be one
less thing to update next time we change autotools version.

I hit a few categories of problems that required some changes.  They are
described below along with the chosen solutions.

Problem 1:

  configure.ac:17: warning: AM_INIT_AUTOMAKE: two- and three-arguments forms are deprecated.  For more info, see:
  configure.ac:17: http://www.gnu.org/software/automake/manual/automake.html#Modernize-AM_005fINIT_005fAUTOMAKE-invocation

Solution 1:

  Adjust the code based on the example at that URL.

Problem 2 (in zlib/):

  Makefile.am: error: required file './INSTALL' not found
  Makefile.am:   'automake --add-missing' can install 'INSTALL'
  Makefile.am: error: required file './NEWS' not found
  Makefile.am: error: required file './AUTHORS' not found
  Makefile.am: error: required file './COPYING' not found
  Makefile.am:   'automake --add-missing' can install 'COPYING'

Solution 2:

  Add the foreign option to AUTOMAKE_OPTIONS.

Problem 3:

  doc/Makefile.am:20: error: support for Cygnus-style trees has been removed

Solution 3:

  Remove the cygnus options.

Problem 4:

  Makefile.am:656: warning: 'INCLUDES' is the old name for 'AM_CPPFLAGS' (or '*_CPPFLAGS')

Solution 4:

  Rename "INCLUDES = " to "AM_CPPFLAGS += " (because AM_CPPFLAGS is
  already defined earlier).

Problem 5:

  doc/Makefile.am:71: warning: suffix '.texinfo' for Texinfo files is discouraged; use '.texi' instead
  doc/Makefile.am: warning: Oops!
  doc/Makefile.am:     It appears this file (or files included by it) are triggering
  doc/Makefile.am:     an undocumented, soon-to-be-removed automake hack.
  doc/Makefile.am:     Future automake versions will no longer place in the builddir
  doc/Makefile.am:     (rather than in the srcdir) the generated '.info' files that
  doc/Makefile.am:     appear to be cleaned, by e.g. being listed in CLEANFILES or
  doc/Makefile.am:     DISTCLEANFILES.
  doc/Makefile.am:     If you want your '.info' files to be placed in the builddir
  doc/Makefile.am:     rather than in the srcdir, you have to use the shiny new
  doc/Makefile.am:     'info-in-builddir' automake option.

Solution 5:

  Rename .texinfo files to .texi.

Problem 6:

  doc/Makefile.am: warning: Oops!
  doc/Makefile.am:     It appears this file (or files included by it) are triggering
  doc/Makefile.am:     an undocumented, soon-to-be-removed automake hack.
  doc/Makefile.am:     Future automake versions will no longer place in the builddir
  doc/Makefile.am:     (rather than in the srcdir) the generated '.info' files that
  doc/Makefile.am:     appear to be cleaned, by e.g. being listed in CLEANFILES or
  doc/Makefile.am:     DISTCLEANFILES.
  doc/Makefile.am:     If you want your '.info' files to be placed in the builddir
  doc/Makefile.am:     rather than in the srcdir, you have to use the shiny new
  doc/Makefile.am:     'info-in-builddir' automake option.

Solution 6:

  Remove the hack at the bottom of doc/Makefile.am and use
  the info-in-builddir automake option.

Problem 7:

  doc/Makefile.am:35: error: required file '../texinfo.tex' not found
  doc/Makefile.am:35:   'automake --add-missing' can install 'texinfo.tex'

Solution 7:

  Use the no-texinfo.tex automake option.  We also have one in
  texinfo/texinfo.tex, not sure if we should point to that, or move it
  (or a newer version of it added with automake --add-missing) to
  top-level.

Problem 8:

  Makefile.am:131: warning: source file 'config/tc-aarch64.c' is in a subdirectory,
  Makefile.am:131: but option 'subdir-objects' is disabled
  automake: warning: possible forward-incompatibility.
  automake: At least a source file is in a subdirectory, but the 'subdir-objects'
  automake: automake option hasn't been enabled.  For now, the corresponding output
  automake: object file(s) will be placed in the top-level directory.  However,
  automake: this behaviour will change in future Automake versions: they will
  automake: unconditionally cause object files to be placed in the same subdirectory
  automake: of the corresponding sources.
  automake: You are advised to start using 'subdir-objects' option throughout your
  automake: project, to avoid future incompatibilities.

Solution 8:

  Use subdir-objects, that means adjusting references to some .o that will now
  be in config/.

Problem 9:

  configure.ac:375: warning: AC_LANG_CONFTEST: no AC_LANG_SOURCE call detected in body
  ../../lib/autoconf/lang.m4:193: AC_LANG_CONFTEST is expanded from...
  ../../lib/autoconf/general.m4:2601: _AC_COMPILE_IFELSE is expanded from...
  ../../lib/autoconf/general.m4:2617: AC_COMPILE_IFELSE is expanded from...
  ../../lib/m4sugar/m4sh.m4:639: AS_IF is expanded from...
  ../../lib/autoconf/general.m4:2042: AC_CACHE_VAL is expanded from...
  ../../lib/autoconf/general.m4:2063: AC_CACHE_CHECK is expanded from...
  configure.ac:375: the top level

Solution 9:

  Use AC_LANG_SOURCE, or use proper quoting.

Problem 10 (in intl/):

  configure.ac:7: warning: AC_COMPILE_IFELSE was called before AC_USE_SYSTEM_EXTENSIONS
  /usr/share/aclocal/threadlib.m4:36: gl_THREADLIB_EARLY_BODY is expanded from...
  /usr/share/aclocal/threadlib.m4:29: gl_THREADLIB_EARLY is expanded from...
  /usr/share/aclocal/threadlib.m4:318: gl_THREADLIB is expanded from...
  /usr/share/aclocal/lock.m4:9: gl_LOCK is expanded from...
  /usr/share/aclocal/intl.m4:211: gt_INTL_SUBDIR_CORE is expanded from...
  /usr/share/aclocal/intl.m4:25: AM_INTL_SUBDIR is expanded from...
  /usr/share/aclocal/gettext.m4:57: AM_GNU_GETTEXT is expanded from...
  configure.ac:7: the top level

Solution 10:

  Add AC_USE_SYSTEM_EXTENSIONS in configure.ac.

ChangeLog:

	* libtool.m4: Use AC_LANG_SOURCE.
	* configure.ac: Remove AC_PREREQ, use AC_LANG_SOURCE.
	* README-maintainer-mode: Update version requirements.
	* ar-lib: New file.
	* test-driver: New file.
	* configure: Re-generate.

bfd/ChangeLog:

	* Makefile.am (AUTOMAKE_OPTIONS): Remove 1.11.
	(INCLUDES): Rename to ...
	(AM_CPPFLAGS): ... this.
	* configure.ac: Remove AC_PREREQ.
	* doc/Makefile.am (AUTOMAKE_OPTIONS): Remove 1.9, cygnus, add
	info-in-builddir no-texinfo.tex.
	(info_TEXINFOS): Rename bfd.texinfo to bfd.texi.
	* doc/bfd.texinfo: Rename to ...
	* doc/bfd.texi: ... this.
	* Makefile.in: Re-generate.
	* aclocal.m4: Re-generate.
	* config.in: Re-generate.
	* configure: Re-generate.
	* doc/Makefile.in: Re-generate.

binutils/ChangeLog:

	* configure.ac: Remove AC_PREREQ.
	* doc/Makefile.am (AUTOMAKE_OPTIONS): Remove cygnus, add
	info-in-builddir no-texinfo.tex.
	* Makefile.in: Re-generate.
	* aclocal.m4: Re-generate.
	* config.in: Re-generate.
	* configure: Re-generate.
	* doc/Makefile.in: Re-generate.

config/ChangeLog:

	* override.m4 (_GCC_AUTOCONF_VERSION): Bump from 2.64 to 2.69.

etc/ChangeLog:

	* configure.in: Remove AC_PREREQ.
	* configure: Re-generate.

gas/ChangeLog:

	* Makefile.am (AUTOMAKE_OPTIONS): Remove 1.11, add subdir-objects.
	(TARG_CPU_O, OBJ_FORMAT_O, ATOF_TARG_O): Add config/ prefix.
	* configure.ac (TARG_CPU_O, OBJ_FORMAT_O, ATOF_TARG_O, emfiles,
	extra_objects): Add config/ prefix.
	* doc/as.texinfo: Rename to...
	* doc/as.texi: ... this.
	* doc/Makefile.am: Rename as.texinfo to as.texi throughout.
	Remove DISTCLEANFILES hack.
	(AUTOMAKE_OPTIONS): Remove 1.8, cygnus, add no-texinfo.tex and
	info-in-builddir.
	* Makefile.in: Re-generate.
	* aclocal.m4: Re-generate.
	* config.in: Re-generate.
	* configure: Re-generate.
	* doc/Makefile.in: Re-generate.

gdb/ChangeLog:

	* common/common-defs.h (PACKAGE_NAME, PACKAGE_VERSION,
	PACKAGE_STRING, PACKAGE_TARNAME): Undefine.
	* configure.ac: Remove AC_PREREQ, add missing quoting.
	* gnulib/configure.ac: Modernize usage of
	AC_INIT/AM_INIT_AUTOMAKE.  Remove AC_PREREQ.
	* gnulib/update-gnulib.sh (AUTOCONF_VERSION): Bump to 2.69.
	(AUTOMAKE_VERSION): Bump to 1.15.1.
	* configure: Re-generate.
	* config.in: Re-generate.
	* aclocal.m4: Re-generate.
	* gnulib/aclocal.m4: Re-generate.
	* gnulib/config.in: Re-generate.
	* gnulib/configure: Re-generate.
	* gnulib/import/Makefile.in: Re-generate.

gdb/gdbserver/ChangeLog:

	* configure.ac: Remove AC_PREREQ, add missing quoting.
	* configure: Re-generate.
	* config.in: Re-generate.
	* aclocal.m4: Re-generate.

gdb/testsuite/ChangeLog:

	* configure.ac: Remove AC_PREREQ.
	* configure: Re-generate.

gold/ChangeLog:

	* configure.ac: Remove AC_PREREQ, add missing quoting and usage
	of AC_LANG_SOURCE.
	* Makefile.in: Re-generate.
	* aclocal.m4: Re-generate.
	* configure: Re-generate.
	* testsuite/Makefile.in: Re-generate.

gprof/ChangeLog:

	* configure.ac: Remove AC_PREREQ.
	* Makefile.am: Remove DISTCLEANFILES hack.
	(AUTOMAKE_OPTIONS): Remove 1.11, add info-in-builddir.
	* Makefile.in: Re-generate.
	* aclocal.m4: Re-generate.
	* configure: Re-generate.
	* gconfig.in: Re-generate.

intl/ChangeLog:

	* configure.ac: Add AC_USE_SYSTEM_EXTENSIONS, remove AC_PREREQ.
	* configure: Re-generate.
	* config.h.in: Re-generate.
	* aclocal.m4: Re-generate.

ld/ChangeLog:

	* configure.ac: Remove AC_PREREQ.
	* Makefile.am: Remove DISTCLEANFILES hack, rename ld.texinfo to
	ld.texi, ldint.texinfo to ldint.texi throughout.
	(AUTOMAKE_OPTIONS): Add info-in-builddir.
	* README: Rename ld.texinfo to ld.texi, ldint.texinfo to
	ldint.texi throughout.
	* gen-doc.texi: Likewise.
	* h8-doc.texi: Likewise.
	* ld.texinfo: Rename to ...
	* ld.texi: ... this.
	* ldint.texinfo: Rename to ...
	* ldint.texi: ... this.
	* Makefile.in: Re-generate.
	* aclocal.m4: Re-generate.
	* config.in: Re-generate.
	* configure: Re-generate.

libdecnumber/ChangeLog:

	* configure.ac: Remove AC_PREREQ.
	* configure: Re-generate.
	* aclocal.m4.

libiberty/ChangeLog:

	* configure.ac: Remove AC_PREREQ.
	* configure: Re-generate.
	* config.in: Re-generate.

opcodes/ChangeLog:

	* Makefile.am (AUTOMAKE_OPTIONS): Remove 1.11.
	* configure.ac: Remove AC_PREREQ.
	* Makefile.in: Re-generate.
	* aclocal.m4: Re-generate.
	* configure: Re-generate.

readline/ChangeLog.gdb:

	* configure: Re-generate.
	* examples/rlfe/configure: Re-generate.

sim/ChangeLog:

	* All configure.ac: Remove AC_PREREQ.
	* All configure: Re-generate.

zlib/ChangeLog.bin-gdb:

	* configure.ac: Modernize AC_INIT call, remove AC_PREREQ.
	* Makefile.am (AUTOMAKE_OPTIONS): Remove 1.8, cygnus, add
	foreign.
	* Makefile.in: Re-generate.
	* aclocal.m4: Re-generate.
	* configure: Re-generate.

1 files changed, 700 insertions, 0 deletions

diff --git a/ld/ldint.texi b/ld/ldint.texi
new file mode 100644
index 0000000..6df7c88
--- /dev/null
+++ b/ld/ldint.texi
@@ -0,0 +1,700 @@
+\input texinfo
+@setfilename ldint.info
+@c Copyright (C) 1992-2018 Free Software Foundation, Inc.
+
+@ifnottex
+@dircategory Software development
+@direntry
+* Ld-Internals: (ldint).	The GNU linker internals.
+@end direntry
+@end ifnottex
+
+@copying
+This file documents the internals of the GNU linker ld.
+
+Copyright @copyright{} 1992-2018 Free Software Foundation, Inc.
+Contributed by Cygnus Support.
+
+Permission is granted to copy, distribute and/or modify this document
+under the terms of the GNU Free Documentation License, Version 1.3 or
+any later version published by the Free Software Foundation; with the
+Invariant Sections being ``GNU General Public License'' and ``Funding
+Free Software'', 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 ``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
+
+@iftex
+@finalout
+@setchapternewpage off
+@settitle GNU Linker Internals
+@titlepage
+@title{A guide to the internals of the GNU linker}
+@author Per Bothner, Steve Chamberlain, Ian Lance Taylor, DJ Delorie
+@author Cygnus Support
+@page
+
+@tex
+\def\$#1${{#1}}  % Kluge: collect RCS revision info without $...$
+\xdef\manvers{2.10.91}  % For use in headers, footers too
+{\parskip=0pt
+\hfill Cygnus Support\par
+\hfill \manvers\par
+\hfill \TeX{}info \texinfoversion\par
+}
+@end tex
+
+@vskip 0pt plus 1filll
+Copyright @copyright{} 1992-2018 Free Software Foundation, Inc.
+
+      Permission is granted to copy, distribute and/or modify this document
+      under the terms of the GNU Free Documentation License, Version 1.3
+      or any later version published by the Free Software Foundation;
+      with no Invariant Sections, with no Front-Cover Texts, and with no
+      Back-Cover Texts.  A copy of the license is included in the
+      section entitled "GNU Free Documentation License".
+
+@end titlepage
+@end iftex
+
+@node Top
+@top
+
+This file documents the internals of the GNU linker @code{ld}.  It is a
+collection of miscellaneous information with little form at this point.
+Mostly, it is a repository into which you can put information about
+GNU @code{ld} as you discover it (or as you design changes to @code{ld}).
+
+This document is distributed under the terms of the GNU Free
+Documentation License.  A copy of the license is included in the
+section entitled "GNU Free Documentation License".
+
+@menu
+* README::			The README File
+* Emulations::			How linker emulations are generated
+* Emulation Walkthrough::	A Walkthrough of a Typical Emulation
+* Architecture Specific::	Some Architecture Specific Notes
+* GNU Free Documentation License::  GNU Free Documentation License
+@end menu
+
+@node README
+@chapter The @file{README} File
+
+Check the @file{README} file; it often has useful information that does not
+appear anywhere else in the directory.
+
+@node Emulations
+@chapter How linker emulations are generated
+
+Each linker target has an @dfn{emulation}.  The emulation includes the
+default linker script, and certain emulations also modify certain types
+of linker behaviour.
+
+Emulations are created during the build process by the shell script
+@file{genscripts.sh}.
+
+The @file{genscripts.sh} script starts by reading a file in the
+@file{emulparams} directory.  This is a shell script which sets various
+shell variables used by @file{genscripts.sh} and the other shell scripts
+it invokes.
+
+The @file{genscripts.sh} script will invoke a shell script in the
+@file{scripttempl} directory in order to create default linker scripts
+written in the linker command language.  The @file{scripttempl} script
+will be invoked 5 (or, in some cases, 6) times, with different
+assignments to shell variables, to create different default scripts.
+The choice of script is made based on the command line options.
+
+After creating the scripts, @file{genscripts.sh} will invoke yet another
+shell script, this time in the @file{emultempl} directory.  That shell
+script will create the emulation source file, which contains C code.
+This C code permits the linker emulation to override various linker
+behaviours.  Most targets use the generic emulation code, which is in
+@file{emultempl/generic.em}.
+
+To summarize, @file{genscripts.sh} reads three shell scripts: an
+emulation parameters script in the @file{emulparams} directory, a linker
+script generation script in the @file{scripttempl} directory, and an
+emulation source file generation script in the @file{emultempl}
+directory.
+
+For example, the Sun 4 linker sets up variables in
+@file{emulparams/sun4.sh}, creates linker scripts using
+@file{scripttempl/aout.sc}, and creates the emulation code using
+@file{emultempl/sunos.em}.
+
+Note that the linker can support several emulations simultaneously,
+depending upon how it is configured.  An emulation can be selected with
+the @code{-m} option.  The @code{-V} option will list all supported
+emulations.
+
+@menu
+* emulation parameters::        @file{emulparams} scripts
+* linker scripts::              @file{scripttempl} scripts
+* linker emulations::           @file{emultempl} scripts
+@end menu
+
+@node emulation parameters
+@section @file{emulparams} scripts
+
+Each target selects a particular file in the @file{emulparams} directory
+by setting the shell variable @code{targ_emul} in @file{configure.tgt}.
+This shell variable is used by the @file{configure} script to control
+building an emulation source file.
+
+Certain conventions are enforced.  Suppose the @code{targ_emul} variable
+is set to @var{emul} in @file{configure.tgt}.  The name of the emulation
+shell script will be @file{emulparams/@var{emul}.sh}.  The
+@file{Makefile} must have a target named @file{e@var{emul}.c}; this
+target must depend upon @file{emulparams/@var{emul}.sh}, as well as the
+appropriate scripts in the @file{scripttempl} and @file{emultempl}
+directories.  The @file{Makefile} target must invoke @code{GENSCRIPTS}
+with two arguments: @var{emul}, and the value of the make variable
+@code{tdir_@var{emul}}.  The value of the latter variable will be set by
+the @file{configure} script, and is used to set the default target
+directory to search.
+
+By convention, the @file{emulparams/@var{emul}.sh} shell script should
+only set shell variables.  It may set shell variables which are to be
+interpreted by the @file{scripttempl} and the @file{emultempl} scripts.
+Certain shell variables are interpreted directly by the
+@file{genscripts.sh} script.
+
+Here is a list of shell variables interpreted by @file{genscripts.sh},
+as well as some conventional shell variables interpreted by the
+@file{scripttempl} and @file{emultempl} scripts.
+
+@table @code
+@item SCRIPT_NAME
+This is the name of the @file{scripttempl} script to use.  If
+@code{SCRIPT_NAME} is set to @var{script}, @file{genscripts.sh} will use
+the script @file{scripttempl/@var{script}.sc}.
+
+@item TEMPLATE_NAME
+This is the name of the @file{emultempl} script to use.  If
+@code{TEMPLATE_NAME} is set to @var{template}, @file{genscripts.sh} will
+use the script @file{emultempl/@var{template}.em}.  If this variable is
+not set, the default value is @samp{generic}.
+
+@item GENERATE_SHLIB_SCRIPT
+If this is set to a nonempty string, @file{genscripts.sh} will invoke
+the @file{scripttempl} script an extra time to create a shared library
+script.  @ref{linker scripts}.
+
+@item OUTPUT_FORMAT
+This is normally set to indicate the BFD output format use (e.g.,
+@samp{"a.out-sunos-big"}.  The @file{scripttempl} script will normally
+use it in an @code{OUTPUT_FORMAT} expression in the linker script.
+
+@item ARCH
+This is normally set to indicate the architecture to use (e.g.,
+@samp{sparc}).  The @file{scripttempl} script will normally use it in an
+@code{OUTPUT_ARCH} expression in the linker script.
+
+@item ENTRY
+Some @file{scripttempl} scripts use this to set the entry address, in an
+@code{ENTRY} expression in the linker script.
+
+@item TEXT_START_ADDR
+Some @file{scripttempl} scripts use this to set the start address of the
+@samp{.text} section.
+
+@item SEGMENT_SIZE
+The @file{genscripts.sh} script uses this to set the default value of
+@code{DATA_ALIGNMENT} when running the @file{scripttempl} script.
+
+@item TARGET_PAGE_SIZE
+If @code{SEGMENT_SIZE} is not defined, the @file{genscripts.sh} script
+uses this to define it.
+
+@item ALIGNMENT
+Some @file{scripttempl} scripts set this to a number to pass to
+@code{ALIGN} to set the required alignment for the @code{end} symbol.
+@end table
+
+@node linker scripts
+@section @file{scripttempl} scripts
+
+Each linker target uses a @file{scripttempl} script to generate the
+default linker scripts.  The name of the @file{scripttempl} script is
+set by the @code{SCRIPT_NAME} variable in the @file{emulparams} script.
+If @code{SCRIPT_NAME} is set to @var{script}, @code{genscripts.sh} will
+invoke @file{scripttempl/@var{script}.sc}.
+
+The @file{genscripts.sh} script will invoke the @file{scripttempl}
+script 5 to 9 times.  Each time it will set the shell variable
+@code{LD_FLAG} to a different value.  When the linker is run, the
+options used will direct it to select a particular script.  (Script
+selection is controlled by the @code{get_script} emulation entry point;
+this describes the conventional behaviour).
+
+The @file{scripttempl} script should just write a linker script, written
+in the linker command language, to standard output.  If the emulation
+name--the name of the @file{emulparams} file without the @file{.sc}
+extension--is @var{emul}, then the output will be directed to
+@file{ldscripts/@var{emul}.@var{extension}} in the build directory,
+where @var{extension} changes each time the @file{scripttempl} script is
+invoked.
+
+Here is the list of values assigned to @code{LD_FLAG}.
+
+@table @code
+@item (empty)
+The script generated is used by default (when none of the following
+cases apply).  The output has an extension of @file{.x}.
+@item n
+The script generated is used when the linker is invoked with the
+@code{-n} option.  The output has an extension of @file{.xn}.
+@item N
+The script generated is used when the linker is invoked with the
+@code{-N} option.  The output has an extension of @file{.xbn}.
+@item r
+The script generated is used when the linker is invoked with the
+@code{-r} option.  The output has an extension of @file{.xr}.
+@item u
+The script generated is used when the linker is invoked with the
+@code{-Ur} option.  The output has an extension of @file{.xu}.
+@item shared
+The @file{scripttempl} script is only invoked with @code{LD_FLAG} set to
+this value if @code{GENERATE_SHLIB_SCRIPT} is defined in the
+@file{emulparams} file.  The @file{emultempl} script must arrange to use
+this script at the appropriate time, normally when the linker is invoked
+with the @code{-shared} option.  The output has an extension of
+@file{.xs}.
+@item c
+The @file{scripttempl} script is only invoked with @code{LD_FLAG} set to
+this value if @code{GENERATE_COMBRELOC_SCRIPT} is defined in the
+@file{emulparams} file or if @code{SCRIPT_NAME} is @code{elf}. The
+@file{emultempl} script must arrange to use this script at the appropriate
+time, normally when the linker is invoked with the @code{-z combreloc}
+option.  The output has an extension of
+@file{.xc}.
+@item cshared
+The @file{scripttempl} script is only invoked with @code{LD_FLAG} set to
+this value if @code{GENERATE_COMBRELOC_SCRIPT} is defined in the
+@file{emulparams} file or if @code{SCRIPT_NAME} is @code{elf} and
+@code{GENERATE_SHLIB_SCRIPT} is defined in the @file{emulparams} file.
+The @file{emultempl} script must arrange to use this script at the
+appropriate time, normally when the linker is invoked with the @code{-shared
+-z combreloc} option.  The output has an extension of @file{.xsc}.
+@item auto_import
+The @file{scripttempl} script is only invoked with @code{LD_FLAG} set to
+this value if @code{GENERATE_AUTO_IMPORT_SCRIPT} is defined in the
+@file{emulparams} file.  The @file{emultempl} script must arrange to
+use this script at the appropriate time, normally when the linker is
+invoked with the @code{--enable-auto-import} option.  The output has
+an extension of @file{.xa}.
+@end table
+
+Besides the shell variables set by the @file{emulparams} script, and the
+@code{LD_FLAG} variable, the @file{genscripts.sh} script will set
+certain variables for each run of the @file{scripttempl} script.
+
+@table @code
+@item RELOCATING
+This will be set to a non-empty string when the linker is doing a final
+relocation (e.g., all scripts other than @code{-r} and @code{-Ur}).
+
+@item CONSTRUCTING
+This will be set to a non-empty string when the linker is building
+global constructor and destructor tables (e.g., all scripts other than
+@code{-r}).
+
+@item DATA_ALIGNMENT
+This will be set to an @code{ALIGN} expression when the output should be
+page aligned, or to @samp{.} when generating the @code{-N} script.
+
+@item CREATE_SHLIB
+This will be set to a non-empty string when generating a @code{-shared}
+script.
+
+@item COMBRELOC
+This will be set to a non-empty string when generating @code{-z combreloc}
+scripts to a temporary file name which can be used during script generation.
+@end table
+
+The conventional way to write a @file{scripttempl} script is to first
+set a few shell variables, and then write out a linker script using
+@code{cat} with a here document.  The linker script will use variable
+substitutions, based on the above variables and those set in the
+@file{emulparams} script, to control its behaviour.
+
+When there are parts of the @file{scripttempl} script which should only
+be run when doing a final relocation, they should be enclosed within a
+variable substitution based on @code{RELOCATING}.  For example, on many
+targets special symbols such as @code{_end} should be defined when doing
+a final link.  Naturally, those symbols should not be defined when doing
+a relocatable link using @code{-r}.  The @file{scripttempl} script
+could use a construct like this to define those symbols:
+@smallexample
+  $@{RELOCATING+ _end = .;@}
+@end smallexample
+This will do the symbol assignment only if the @code{RELOCATING}
+variable is defined.
+
+The basic job of the linker script is to put the sections in the correct
+order, and at the correct memory addresses.  For some targets, the
+linker script may have to do some other operations.
+
+For example, on most MIPS platforms, the linker is responsible for
+defining the special symbol @code{_gp}, used to initialize the
+@code{$gp} register.  It must be set to the start of the small data
+section plus @code{0x8000}.  Naturally, it should only be defined when
+doing a final relocation.  This will typically be done like this:
+@smallexample
+  $@{RELOCATING+ _gp = ALIGN(16) + 0x8000;@}
+@end smallexample
+This line would appear just before the sections which compose the small
+data section (@samp{.sdata}, @samp{.sbss}).  All those sections would be
+contiguous in memory.
+
+Many COFF systems build constructor tables in the linker script.  The
+compiler will arrange to output the address of each global constructor
+in a @samp{.ctor} section, and the address of each global destructor in
+a @samp{.dtor} section (this is done by defining
+@code{ASM_OUTPUT_CONSTRUCTOR} and @code{ASM_OUTPUT_DESTRUCTOR} in the
+@code{gcc} configuration files).  The @code{gcc} runtime support
+routines expect the constructor table to be named @code{__CTOR_LIST__}.
+They expect it to be a list of words, with the first word being the
+count of the number of entries.  There should be a trailing zero word.
+(Actually, the count may be -1 if the trailing word is present, and the
+trailing word may be omitted if the count is correct, but, as the
+@code{gcc} behaviour has changed slightly over the years, it is safest
+to provide both).  Here is a typical way that might be handled in a
+@file{scripttempl} file.
+@smallexample
+    $@{CONSTRUCTING+ __CTOR_LIST__ = .;@}
+    $@{CONSTRUCTING+ LONG((__CTOR_END__ - __CTOR_LIST__) / 4 - 2)@}
+    $@{CONSTRUCTING+ *(.ctors)@}
+    $@{CONSTRUCTING+ LONG(0)@}
+    $@{CONSTRUCTING+ __CTOR_END__ = .;@}
+    $@{CONSTRUCTING+ __DTOR_LIST__ = .;@}
+    $@{CONSTRUCTING+ LONG((__DTOR_END__ - __DTOR_LIST__) / 4 - 2)@}
+    $@{CONSTRUCTING+ *(.dtors)@}
+    $@{CONSTRUCTING+ LONG(0)@}
+    $@{CONSTRUCTING+ __DTOR_END__ = .;@}
+@end smallexample
+The use of @code{CONSTRUCTING} ensures that these linker script commands
+will only appear when the linker is supposed to be building the
+constructor and destructor tables.  This example is written for a target
+which uses 4 byte pointers.
+
+Embedded systems often need to set a stack address.  This is normally
+best done by using the @code{PROVIDE} construct with a default stack
+address.  This permits the user to easily override the stack address
+using the @code{--defsym} option.  Here is an example:
+@smallexample
+  $@{RELOCATING+ PROVIDE (__stack = 0x80000000);@}
+@end smallexample
+The value of the symbol @code{__stack} would then be used in the startup
+code to initialize the stack pointer.
+
+@node linker emulations
+@section @file{emultempl} scripts
+
+Each linker target uses an @file{emultempl} script to generate the
+emulation code.  The name of the @file{emultempl} script is set by the
+@code{TEMPLATE_NAME} variable in the @file{emulparams} script.  If the
+@code{TEMPLATE_NAME} variable is not set, the default is
+@samp{generic}.  If the value of @code{TEMPLATE_NAME} is @var{template},
+@file{genscripts.sh} will use @file{emultempl/@var{template}.em}.
+
+Most targets use the generic @file{emultempl} script,
+@file{emultempl/generic.em}.  A different @file{emultempl} script is
+only needed if the linker must support unusual actions, such as linking
+against shared libraries.
+
+The @file{emultempl} script is normally written as a simple invocation
+of @code{cat} with a here document.  The document will use a few
+variable substitutions.  Typically each function names uses a
+substitution involving @code{EMULATION_NAME}, for ease of debugging when
+the linker supports multiple emulations.
+
+Every function and variable in the emitted file should be static.  The
+only globally visible object must be named
+@code{ld_@var{EMULATION_NAME}_emulation}, where @var{EMULATION_NAME} is
+the name of the emulation set in @file{configure.tgt} (this is also the
+name of the @file{emulparams} file without the @file{.sh} extension).
+The @file{genscripts.sh} script will set the shell variable
+@code{EMULATION_NAME} before invoking the @file{emultempl} script.
+
+The @code{ld_@var{EMULATION_NAME}_emulation} variable must be a
+@code{struct ld_emulation_xfer_struct}, as defined in @file{ldemul.h}.
+It defines a set of function pointers which are invoked by the linker,
+as well as strings for the emulation name (normally set from the shell
+variable @code{EMULATION_NAME} and the default BFD target name (normally
+set from the shell variable @code{OUTPUT_FORMAT} which is normally set
+by the @file{emulparams} file).
+
+The @file{genscripts.sh} script will set the shell variable
+@code{COMPILE_IN} when it invokes the @file{emultempl} script for the
+default emulation.  In this case, the @file{emultempl} script should
+include the linker scripts directly, and return them from the
+@code{get_scripts} entry point.  When the emulation is not the default,
+the @code{get_scripts} entry point should just return a file name.  See
+@file{emultempl/generic.em} for an example of how this is done.
+
+At some point, the linker emulation entry points should be documented.
+
+@node Emulation Walkthrough
+@chapter A Walkthrough of a Typical Emulation
+
+This chapter is to help people who are new to the way emulations
+interact with the linker, or who are suddenly thrust into the position
+of having to work with existing emulations.  It will discuss the files
+you need to be aware of.  It will tell you when the given "hooks" in
+the emulation will be called.  It will, hopefully, give you enough
+information about when and how things happen that you'll be able to
+get by.  As always, the source is the definitive reference to this.
+
+The starting point for the linker is in @file{ldmain.c} where
+@code{main} is defined.  The bulk of the code that's emulation
+specific will initially be in @code{emultempl/@var{emulation}.em} but
+will end up in @code{e@var{emulation}.c} when the build is done.
+Most of the work to select and interface with emulations is in
+@code{ldemul.h} and @code{ldemul.c}.  Specifically, @code{ldemul.h}
+defines the @code{ld_emulation_xfer_struct} structure your emulation
+exports.
+
+Your emulation file exports a symbol
+@code{ld_@var{EMULATION_NAME}_emulation}.  If your emulation is
+selected (it usually is, since usually there's only one),
+@code{ldemul.c} sets the variable @var{ld_emulation} to point to it.
+@code{ldemul.c} also defines a number of API functions that interface
+to your emulation, like @code{ldemul_after_parse} which simply calls
+your @code{ld_@var{EMULATION}_emulation.after_parse} function.  For
+the rest of this section, the functions will be mentioned, but you
+should assume the indirect reference to your emulation also.
+
+We will also skip or gloss over parts of the link process that don't
+relate to emulations, like setting up internationalization.
+
+After initialization, @code{main} selects an emulation by pre-scanning
+the command line arguments.  It calls @code{ldemul_choose_target} to
+choose a target.  If you set @code{choose_target} to
+@code{ldemul_default_target}, it picks your @code{target_name} by
+default.
+
+@code{main} calls @code{ldemul_before_parse}, then @code{parse_args}.
+@code{parse_args} calls @code{ldemul_parse_args} for each arg, which
+must update the @code{getopt} globals if it recognizes the argument.
+If the emulation doesn't recognize it, then parse_args checks to see
+if it recognizes it.
+
+Now that the emulation has had access to all its command-line options,
+@code{main} calls @code{ldemul_set_symbols}.  This can be used for any
+initialization that may be affected by options.  It is also supposed
+to set up any variables needed by the emulation script.
+
+@code{main} now calls @code{ldemul_get_script} to get the emulation
+script to use (based on arguments, no doubt, @pxref{Emulations}) and
+runs it.  While parsing, @code{ldgram.y} may call @code{ldemul_hll} or
+@code{ldemul_syslib} to handle the @code{HLL} or @code{SYSLIB}
+commands.  It may call @code{ldemul_unrecognized_file} if you asked
+the linker to link a file it doesn't recognize.  It will call
+@code{ldemul_recognized_file} for each file it does recognize, in case
+the emulation wants to handle some files specially.  All the while,
+it's loading the files (possibly calling
+@code{ldemul_open_dynamic_archive}) and symbols and stuff.  After it's
+done reading the script, @code{main} calls @code{ldemul_after_parse}.
+Use the after-parse hook to set up anything that depends on stuff the
+script might have set up, like the entry point.
+
+@code{main} next calls @code{lang_process} in @code{ldlang.c}.  This
+appears to be the main core of the linking itself, as far as emulation
+hooks are concerned(*).  It first opens the output file's BFD, calling
+@code{ldemul_set_output_arch}, and calls
+@code{ldemul_create_output_section_statements} in case you need to use
+other means to find or create object files (i.e. shared libraries
+found on a path, or fake stub objects).  Despite the name, nobody
+creates output sections here.
+
+(*) In most cases, the BFD library does the bulk of the actual
+linking, handling symbol tables, symbol resolution, relocations, and
+building the final output file.  See the BFD reference for all the
+details.  Your emulation is usually concerned more with managing
+things at the file and section level, like "put this here, add this
+section", etc.
+
+Next, the objects to be linked are opened and BFDs created for them,
+and @code{ldemul_after_open} is called.  At this point, you have all
+the objects and symbols loaded, but none of the data has been placed
+yet.
+
+Next comes the Big Linking Thingy (except for the parts BFD does).
+All input sections are mapped to output sections according to the
+script.  If a section doesn't get mapped by default,
+@code{ldemul_place_orphan} will get called to figure out where it goes.
+Next it figures out the offsets for each section, calling
+@code{ldemul_before_allocation} before and
+@code{ldemul_after_allocation} after deciding where each input section
+ends up in the output sections.
+
+The last part of @code{lang_process} is to figure out all the symbols'
+values.  After assigning final values to the symbols,
+@code{ldemul_finish} is called, and after that, any undefined symbols
+are turned into fatal errors.
+
+OK, back to @code{main}, which calls @code{ldwrite} in
+@file{ldwrite.c}.  @code{ldwrite} calls BFD's final_link, which does
+all the relocation fixups and writes the output bfd to disk, and we're
+done.
+
+In summary,
+
+@itemize @bullet
+
+@item @code{main()} in @file{ldmain.c}
+@item @file{emultempl/@var{EMULATION}.em} has your code
+@item @code{ldemul_choose_target} (defaults to your @code{target_name})
+@item @code{ldemul_before_parse}
+@item Parse argv, calls @code{ldemul_parse_args} for each
+@item @code{ldemul_set_symbols}
+@item @code{ldemul_get_script}
+@item parse script
+
+@itemize @bullet
+@item may call @code{ldemul_hll} or @code{ldemul_syslib}
+@item may call @code{ldemul_open_dynamic_archive}
+@end itemize
+
+@item @code{ldemul_after_parse}
+@item @code{lang_process()} in @file{ldlang.c}
+
+@itemize @bullet
+@item create @code{output_bfd}
+@item @code{ldemul_set_output_arch}
+@item @code{ldemul_create_output_section_statements}
+@item read objects, create input bfds - all symbols exist, but have no values
+@item may call @code{ldemul_unrecognized_file}
+@item will call @code{ldemul_recognized_file}
+@item @code{ldemul_after_open}
+@item map input sections to output sections
+@item may call @code{ldemul_place_orphan} for remaining sections
+@item @code{ldemul_before_allocation}
+@item gives input sections offsets into output sections, places output sections
+@item @code{ldemul_after_allocation} - section addresses valid
+@item assigns values to symbols
+@item @code{ldemul_finish} - symbol values valid
+@end itemize
+
+@item output bfd is written to disk
+
+@end itemize
+
+@node Architecture Specific
+@chapter Some Architecture Specific Notes
+
+This is the place for notes on the behavior of @code{ld} on
+specific platforms.  Currently, only Intel x86 is documented (and
+of that, only the auto-import behavior for DLLs).
+
+@menu
+* ix86::                        Intel x86
+@end menu
+
+@node ix86
+@section Intel x86
+
+@table @emph
+@code{ld} can create DLLs that operate with various runtimes available
+on a common x86 operating system.  These runtimes include native (using
+the mingw "platform"), cygwin, and pw.
+
+@item auto-import from DLLs
+@enumerate
+@item
+With this feature on, DLL clients can import variables from DLL
+without any concern from their side (for example, without any source
+code modifications).  Auto-import can be enabled using the
+@code{--enable-auto-import} flag, or disabled via the
+@code{--disable-auto-import} flag.  Auto-import is disabled by default.
+
+@item
+This is done completely in bounds of the PE specification (to be fair,
+there's a minor violation of the spec at one point, but in practice
+auto-import works on all known variants of that common x86 operating
+system)  So, the resulting DLL can be used with any other PE
+compiler/linker.
+
+@item
+Auto-import is fully compatible with standard import method, in which
+variables are decorated using attribute modifiers. Libraries of either
+type may be mixed together.
+
+@item
+Overhead (space): 8 bytes per imported symbol, plus 20 for each
+reference to it; Overhead (load time): negligible; Overhead
+(virtual/physical memory): should be less than effect of DLL
+relocation.
+@end enumerate
+
+Motivation
+
+The obvious and only way to get rid of dllimport insanity is
+to make client access variable directly in the DLL, bypassing
+the extra dereference imposed by ordinary DLL runtime linking.
+I.e., whenever client contains something like
+
+@code{mov dll_var,%eax,}
+
+address of dll_var in the command should be relocated to point
+into loaded DLL. The aim is to make OS loader do so, and than
+make ld help with that.  Import section of PE made following
+way: there's a vector of structures each describing imports
+from particular DLL. Each such structure points to two other
+parallel vectors: one holding imported names, and one which
+will hold address of corresponding imported name. So, the
+solution is de-vectorize these structures, making import
+locations be sparse and pointing directly into code.
+
+Implementation
+
+For each reference of data symbol to be imported from DLL (to
+set of which belong symbols with name <sym>, if __imp_<sym> is
+found in implib), the import fixup entry is generated. That
+entry is of type IMAGE_IMPORT_DESCRIPTOR and stored in .idata$3
+subsection. Each fixup entry contains pointer to symbol's address
+within .text section (marked with __fuN_<sym> symbol, where N is
+integer), pointer to DLL name (so, DLL name is referenced by
+multiple entries), and pointer to symbol name thunk. Symbol name
+thunk is singleton vector (__nm_th_<symbol>) pointing to
+IMAGE_IMPORT_BY_NAME structure (__nm_<symbol>) directly containing
+imported name. Here comes that "om the edge" problem mentioned above:
+PE specification rambles that name vector (OriginalFirstThunk) should
+run in parallel with addresses vector (FirstThunk), i.e. that they
+should have same number of elements and terminated with zero. We violate
+this, since FirstThunk points directly into machine code. But in
+practice, OS loader implemented the sane way: it goes thru
+OriginalFirstThunk and puts addresses to FirstThunk, not something
+else. It once again should be noted that dll and symbol name
+structures are reused across fixup entries and should be there
+anyway to support standard import stuff, so sustained overhead is
+20 bytes per reference. Other question is whether having several
+IMAGE_IMPORT_DESCRIPTORS for the same DLL is possible. Answer is yes,
+it is done even by native compiler/linker (libth32's functions are in
+fact resident in windows9x kernel32.dll, so if you use it, you have
+two IMAGE_IMPORT_DESCRIPTORS for kernel32.dll). Yet other question is
+whether referencing the same PE structures several times is valid.
+The answer is why not, prohibiting that (detecting violation) would
+require more work on behalf of loader than not doing it.
+
+@end table
+
+@node GNU Free Documentation License
+@chapter GNU Free Documentation License
+
+@include fdl.texi
+
+@contents
+@bye