\input texinfo
@setfilename ld.info
@c Copyright 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000,
-@c 2001 Free Software Foundation, Inc.
+@c 2001, 2002, 2003 Free Software Foundation, Inc.
@syncodeindex ky cp
@include configdoc.texi
@c (configdoc.texi is generated by the Makefile)
@c @smallbook
+@macro gcctabopt{body}
+@code{\body\}
+@end macro
+
@c man begin NAME
@ifset man
@c Configure for the generation of man pages
@set M680X0
@set MCORE
@set MIPS
+@set MMIX
+@set MSP430
@set PDP11
@set PJ
@set SH
@set C54X
@set V850
@set VAX
+@set WIN32
@end ifset
@c man end
This file documents the @sc{gnu} linker LD version @value{VERSION}.
Copyright (C) 1991, 92, 93, 94, 95, 96, 97, 98, 99, 2000,
-2001 Free Software Foundation, Inc.
+2001, 2002, 2003 Free Software Foundation, Inc.
@ignore
@vskip 0pt plus 1filll
@c man begin COPYRIGHT
-Copyright @copyright{} 1991, 92, 93, 94, 95, 96, 97, 98, 99, 2000 Free Software Foundation, Inc.
+Copyright @copyright{} 1991, 92, 93, 94, 95, 96, 97, 98, 99, 2000, 2001,
+2002, 2003 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 1.1
@end iftex
@c FIXME: Talk about importance of *order* of args, cmds to linker!
-@ifinfo
+@ifnottex
@node Top
@top Using ld
This file documents the @sc{gnu} linker ld version @value{VERSION}.
@ifset TICOFF
* TI COFF:: ld and the TI COFF
@end ifset
+@ifset WIN32
+* Win32:: ld and WIN32 (cygwin/mingw)
+@end ifset
@end ifclear
@ifclear SingleFormat
* BFD:: BFD
* GNU Free Documentation License:: GNU Free Documentation License
* Index:: Index
@end menu
-@end ifinfo
+@end ifnottex
@node Overview
@chapter Overview
@ifset man
@c man begin SYNOPSIS
-ld [ options ] objfile...
+ld [@b{options}] @var{objfile} @dots{}
@c man end
@c man begin SEEALSO
@c man begin DESCRIPTION
-@code{ld} combines a number of object and archive files, relocates
+@command{ld} combines a number of object and archive files, relocates
their data and ties up symbol references. Usually the last step in
-compiling a program is to run @code{ld}.
+compiling a program is to run @command{ld}.
-@code{ld} accepts Linker Command Language files written in
+@command{ld} accepts Linker Command Language files written in
a superset of AT&T's Link Editor Command Language syntax,
to provide explicit and total control over the linking process.
@ifset man
@c For the man only
This man page does not describe the command language; see the
-@code{ld} entry in @code{info}, or the manual
+@command{ld} entry in @code{info}, or the manual
ld: the GNU linker, for full details on the command language and
on other aspects of the GNU linker.
@end ifset
@ifclear SingleFormat
-This version of @code{ld} uses the general purpose BFD libraries
-to operate on object files. This allows @code{ld} to read, combine, and
+This version of @command{ld} uses the general purpose BFD libraries
+to operate on object files. This allows @command{ld} to read, combine, and
write object files in many different formats---for example, COFF or
@code{a.out}. Different formats may be linked together to produce any
available kind of object file. @xref{BFD}, for more information.
Aside from its flexibility, the @sc{gnu} linker is more helpful than other
linkers in providing diagnostic information. Many linkers abandon
execution immediately upon encountering an error; whenever possible,
-@code{ld} continues executing, allowing you to identify other errors
+@command{ld} continues executing, allowing you to identify other errors
(or, in some cases, to get an output file in spite of the error).
@c man end
@c man begin DESCRIPTION
-The @sc{gnu} linker @code{ld} is meant to cover a broad range of situations,
+The @sc{gnu} linker @command{ld} is meant to cover a broad range of situations,
and to be as compatible as possible with other linkers. As a result,
you have many choices to control its behavior.
The linker supports a plethora of command-line options, but in actual
practice few of them are used in any particular context.
@cindex standard Unix system
-For instance, a frequent use of @code{ld} is to link standard Unix
+For instance, a frequent use of @command{ld} is to link standard Unix
object files on a standard, supported Unix system. On such a system, to
link a file @code{hello.o}:
ld -o @var{output} /lib/crt0.o hello.o -lc
@end smallexample
-This tells @code{ld} to produce a file called @var{output} as the
+This tells @command{ld} to produce a file called @var{output} as the
result of linking the file @code{/lib/crt0.o} with @code{hello.o} and
the library @code{libc.a}, which will come from the standard search
directories. (See the discussion of the @samp{-l} option below.)
-Some of the command-line options to @code{ld} may be specified at any
+Some of the command-line options to @command{ld} may be specified at any
point in the command line. However, options which refer to files, such
as @samp{-l} or @samp{-T}, cause the file to be read at the point at
which the option appears in the command line, relative to the object
permits the linker to link against a file which appears to be an object
or an archive, but actually merely defines some symbol values, or uses
@code{INPUT} or @code{GROUP} to load other objects. Note that
-specifying a script in this way should only be used to augment the main
-linker script; if you want to use some command that logically can only
-appear once, such as the @code{SECTIONS} or @code{MEMORY} command, you
-must replace the default linker script using the @samp{-T} option.
+specifying a script in this way merely augments the main linker script;
+use the @samp{-T} option to replace the default linker script entirely.
@xref{Scripts}.
For options whose names are a single letter,
Here is a table of the generic command line switches accepted by the GNU
linker:
-@table @code
+@table @gcctabopt
@kindex -a@var{keyword}
@item -a@var{keyword}
This option is supported for HP/UX compatibility. The @var{keyword}
@item -A@var{architecture}
@kindex --architecture=@var{arch}
@itemx --architecture=@var{architecture}
-In the current release of @code{ld}, this option is useful only for the
-Intel 960 family of architectures. In that @code{ld} configuration, the
+In the current release of @command{ld}, this option is useful only for the
+Intel 960 family of architectures. In that @command{ld} configuration, the
@var{architecture} argument identifies the particular architecture in
the 960 family, enabling some safeguards and modifying the
-archive-library search path. @xref{i960,,@code{ld} and the Intel 960
+archive-library search path. @xref{i960,,@command{ld} and the Intel 960
family}, for details.
-Future releases of @code{ld} may support similar functionality for
+Future releases of @command{ld} may support similar functionality for
other architecture families.
@end ifset
@cindex input format
@item -b @var{input-format}
@itemx --format=@var{input-format}
-@code{ld} may be configured to support more than one kind of object
-file. If your @code{ld} is configured this way, you can use the
+@command{ld} may be configured to support more than one kind of object
+file. If your @command{ld} is configured this way, you can use the
@samp{-b} option to specify the binary format for input object files
-that follow this option on the command line. Even when @code{ld} is
+that follow this option on the command line. Even when @command{ld} is
configured to support alternative object formats, you don't usually need
-to specify this, as @code{ld} should be configured to expect as a
+to specify this, as @command{ld} should be configured to expect as a
default input format the most usual format on each machine.
@var{input-format} is a text string, the name of a particular format
supported by the BFD libraries. (You can list the available binary
@cindex compatibility, MRI
@item -c @var{MRI-commandfile}
@itemx --mri-script=@var{MRI-commandfile}
-For compatibility with linkers produced by MRI, @code{ld} accepts script
+For compatibility with linkers produced by MRI, @command{ld} accepts script
files written in an alternate, restricted command language, described in
@ifclear man
@ref{MRI,,MRI Compatible Script Files}.
@end ifset
Introduce MRI script files with
the option @samp{-c}; use the @samp{-T} option to run linker
-scripts written in the general-purpose @code{ld} scripting language.
-If @var{MRI-cmdfile} does not exist, @code{ld} looks for it in the directories
+scripts written in the general-purpose @command{ld} scripting language.
+If @var{MRI-cmdfile} does not exist, @command{ld} looks for it in the directories
specified by any @samp{-L} options.
@cindex common allocation
used to select a subset of the symbols provided by the object
@var{name}.
-Some older linkers used the @code{-F} option throughout a compilation
+Some older linkers used the @option{-F} option throughout a compilation
toolchain for specifying object-file format for both input and output
object files. The @sc{gnu} linker uses other mechanisms for this
-purpose: the @code{-b}, @code{--format}, @code{--oformat} options, the
+purpose: the @option{-b}, @option{--format}, @option{--oformat} options, the
@code{TARGET} command in linker scripts, and the @code{GNUTARGET}
-environment variable. The @sc{gnu} linker will ignore the @code{-F}
+environment variable. The @sc{gnu} linker will ignore the @option{-F}
option when not creating an ELF shared object.
@cindex finalization function
@item -l@var{archive}
@itemx --library=@var{archive}
Add archive file @var{archive} to the list of files to link. This
-option may be used any number of times. @code{ld} will search its
+option may be used any number of times. @command{ld} will search its
path-list for occurrences of @code{lib@var{archive}.a} for every
@var{archive} specified.
-On systems which support shared libraries, @code{ld} may also search for
+On systems which support shared libraries, @command{ld} may also search for
libraries with extensions other than @code{.a}. Specifically, on ELF
-and SunOS systems, @code{ld} will search a directory for a library with
+and SunOS systems, @command{ld} will search a directory for a library with
an extension of @code{.so} before searching for one with an extension of
@code{.a}. By convention, a @code{.so} extension indicates a shared
library.
archive. However, an undefined symbol in an object appearing later on
the command line will not cause the linker to search the archive again.
-See the @code{-(} option for a way to force the linker to search
+See the @option{-(} option for a way to force the linker to search
archives multiple times.
You may list the same archive multiple times on the command line.
@ifset GENERIC
This type of archive searching is standard for Unix linkers. However,
-if you are using @code{ld} on AIX, note that it is different from the
+if you are using @command{ld} on AIX, note that it is different from the
behaviour of the AIX linker.
@end ifset
@kindex --library-path=@var{dir}
@item -L@var{searchdir}
@itemx --library-path=@var{searchdir}
-Add path @var{searchdir} to the list of paths that @code{ld} will search
-for archive libraries and @code{ld} control scripts. You may use this
+Add path @var{searchdir} to the list of paths that @command{ld} will search
+for archive libraries and @command{ld} control scripts. You may use this
option any number of times. The directories are searched in the order
in which they are specified on the command line. Directories specified
on the command line are searched before the default directories. All
-@code{-L} options apply to all @code{-l} options, regardless of the
+@option{-L} options apply to all @option{-l} options, regardless of the
order in which the options appear.
+If @var{searchdir} begins with @code{=}, then the @code{=} will be replaced
+by the @dfn{sysroot prefix}, a path specified when the linker is configured.
+
@ifset UsesEnvVars
The default set of paths searched (without being specified with
-@samp{-L}) depends on which emulation mode @code{ld} is using, and in
+@samp{-L}) depends on which emulation mode @command{ld} is using, and in
some cases also on how it was configured. @xref{Environment}.
@end ifset
@item -N
@itemx --omagic
Set the text and data sections to be readable and writable. Also, do
-not page-align the data segment. If the output format supports Unix
-style magic numbers, mark the output as @code{OMAGIC}.
+not page-align the data segment, and disable linking against shared
+libraries. If the output format supports Unix style magic numbers,
+mark the output as @code{OMAGIC}.
+
+@kindex --no-omagic
+@cindex OMAGIC
+@item --no-omagic
+This option negates most of the effects of the @option{-N} option. It
+sets the text section to be read-only, and forces the data segment to
+be page-aligned. Note - this option does not enable linking against
+shared libraries. Use @option{-Bdynamic} for this.
@kindex -o @var{output}
@kindex --output=@var{output}
@cindex naming the output file
@item -o @var{output}
@itemx --output=@var{output}
-Use @var{output} as the name for the program produced by @code{ld}; if this
+Use @var{output} as the name for the program produced by @command{ld}; if this
option is not specified, the name @file{a.out} is used by default. The
script command @code{OUTPUT} can also specify the output file name.
@kindex -O @var{level}
@cindex generating optimized output
@item -O @var{level}
-If @var{level} is a numeric values greater than zero @code{ld} optimizes
+If @var{level} is a numeric values greater than zero @command{ld} optimizes
the output. This might take significantly longer and therefore probably
should only be enabled for the final binary.
order to perform correct modifications of executables. This results
in larger executables.
+This option is currently only supported on ELF platforms.
+
@cindex partial link
@cindex relocatable output
@kindex -r
@item -r
@itemx --relocateable
Generate relocatable output---i.e., generate an output file that can in
-turn serve as input to @code{ld}. This is often called @dfn{partial
+turn serve as input to @command{ld}. This is often called @dfn{partial
linking}. As a side effect, in environments that support standard Unix
magic numbers, this option also sets the output file's magic number to
@code{OMAGIC}.
-@c ; see @code{-N}.
+@c ; see @option{-N}.
If this option is not specified, an absolute file is produced. When
linking C++ programs, this option @emph{will not} resolve references to
constructors; to do that, use @samp{-Ur}.
to refer symbolically to absolute locations of memory defined in other
programs. You may use this option more than once.
-For compatibility with other ELF linkers, if the @code{-R} option is
+For compatibility with other ELF linkers, if the @option{-R} option is
followed by a directory name, rather than a file name, it is treated as
-the @code{-rpath} option.
+the @option{-rpath} option.
@kindex -s
@kindex --strip-all
@cindex input files, displaying
@item -t
@itemx --trace
-Print the names of the input files as @code{ld} processes them.
+Print the names of the input files as @command{ld} processes them.
@kindex -T @var{script}
@kindex --script=@var{script}
@item -T @var{scriptfile}
@itemx --script=@var{scriptfile}
Use @var{scriptfile} as the linker script. This script replaces
-@code{ld}'s default linker script (rather than adding to it), so
+@command{ld}'s default linker script (rather than adding to it), so
@var{commandfile} must specify everything necessary to describe the
-output file. You must use this option if you want to use a command
-which can only appear once in a linker script, such as the
-@code{SECTIONS} or @code{MEMORY} command. @xref{Scripts}. If
-@var{scriptfile} does not exist in the current directory, @code{ld}
-looks for it in the directories specified by any preceding @samp{-L}
-options. Multiple @samp{-T} options accumulate.
+output file. @xref{Scripts}. If @var{scriptfile} does not exist in
+the current directory, @code{ld} looks for it in the directories
+specified by any preceding @samp{-L} options. Multiple @samp{-T}
+options accumulate.
@kindex -u @var{symbol}
@kindex --undefined=@var{symbol}
@item -Ur
For anything other than C++ programs, this option is equivalent to
@samp{-r}: it generates relocatable output---i.e., an output file that can in
-turn serve as input to @code{ld}. When linking C++ programs, @samp{-Ur}
+turn serve as input to @command{ld}. When linking C++ programs, @samp{-Ur}
@emph{does} resolve references to constructors, unlike @samp{-r}.
It does not work to use @samp{-Ur} on files that were themselves linked
with @samp{-Ur}; once the constructor table has been built, it cannot
@item -v
@itemx --version
@itemx -V
-Display the version number for @code{ld}. The @code{-V} option also
+Display the version number for @command{ld}. The @option{-V} option also
lists the supported emulations.
@kindex -x
@item -z @var{keyword}
The recognized keywords are @code{initfirst}, @code{interpose},
@code{loadfltr}, @code{nodefaultlib}, @code{nodelete}, @code{nodlopen},
-@code{nodump}, @code{now} and @code{origin}. The other keywords are
+@code{nodump}, @code{now}, @code{origin}, @code{combreloc}, @code{nocombreloc}
+and @code{nocopyreloc}.
+The other keywords are
ignored for Solaris compatibility. @code{initfirst} marks the object
to be initialized first at runtime before any other objects.
@code{interpose} marks the object that its symbol table interposes
@code{now} marks the object with the non-lazy runtime binding.
@code{origin} marks the object may contain $ORIGIN.
@code{defs} disallows undefined symbols.
+@code{muldefs} allows multiple definitions.
+@code{combreloc} combines multiple reloc sections and sorts them
+to make dynamic symbol lookup caching possible.
+@code{nocombreloc} disables multiple reloc sections combining.
+@code{nocopyreloc} disables production of copy relocs.
@kindex -(
@cindex groups of archives
it only when there are unavoidable circular references between two or
more archives.
+@kindex --accept-unknown-input-arch
+@kindex --no-accept-unknown-input-arch
+@item --accept-unknown-input-arch
+@itemx --no-accept-unknown-input-arch
+Tells the linker to accept input files whose architecture cannot be
+recognised. The assumption is that the user knows what they are doing
+and deliberately wants to link in these unknown input files. This was
+the default behaviour of the linker, before release 2.14. The default
+behaviour from release 2.14 onwards is to reject such input files, and
+so the @samp{--accept-unknown-input-arch} option has been added to
+restore the old behaviour.
+
@kindex -assert @var{keyword}
@item -assert @var{keyword}
This option is ignored for SunOS compatibility.
default on such platforms. The different variants of this option are
for compatibility with various systems. You may use this option
multiple times on the command line: it affects library searching for
-@code{-l} options which follow it.
+@option{-l} options which follow it.
@kindex -Bgroup
@item -Bgroup
Set the @code{DF_1_GROUP} flag in the @code{DT_FLAGS_1} entry in the dynamic
section. This causes the runtime linker to handle lookups in this
object and its dependencies to be performed only inside the group.
-@code{--no-undefined} is implied. This option is only meaningful on ELF
+@option{--no-undefined} is implied. This option is only meaningful on ELF
platforms which support shared libraries.
@kindex -Bstatic
platforms for which shared libraries are supported. The different
variants of this option are for compatibility with various systems. You
may use this option multiple times on the command line: it affects
-library searching for @code{-l} options which follow it.
+library searching for @option{-l} options which follow it.
@kindex -Bsymbolic
@item -Bsymbolic
symbol is defined, the first file listed is the location of the
definition. The remaining files contain references to the symbol.
+@cindex common allocation
+@kindex --no-define-common
+@item --no-define-common
+This option inhibits the assignment of addresses to common symbols.
+The script command @code{INHIBIT_COMMON_ALLOCATION} has the same effect.
+@xref{Miscellaneous Commands}.
+
+The @samp{--no-define-common} option allows decoupling
+the decision to assign addresses to Common symbols from the choice
+of the output file type; otherwise a non-Relocatable output type
+forces assigning addresses to Common symbols.
+Using @samp{--no-define-common} allows Common symbols that are referenced
+from a shared library to be assigned addresses only in the main program.
+This eliminates the unused duplicate space in the shared library,
+and also prevents any possible confusion over resolving to the wrong
+duplicate when there are many dynamic modules with specialized search
+paths for runtime symbol resolution.
+
@cindex symbols, from command line
@kindex --defsym @var{symbol}=@var{exp}
@item --defsym @var{symbol}=@var{expression}
@cindex memory usage
@kindex --no-keep-memory
@item --no-keep-memory
-@code{ld} normally optimizes for speed over memory usage by caching the
-symbol tables of input files in memory. This option tells @code{ld} to
+@command{ld} normally optimizes for speed over memory usage by caching the
+symbol tables of input files in memory. This option tells @command{ld} to
instead optimize for memory usage, by rereading the symbol tables as
-necessary. This may be required if @code{ld} runs out of memory space
+necessary. This may be required if @command{ld} runs out of memory space
while linking a large executable.
@kindex --no-undefined
@item --no-undefined
@itemx -z defs
Normally when creating a non-symbolic shared library, undefined symbols
-are allowed and left to be resolved by the runtime loader. These options
-disallows such undefined symbols.
+are allowed and left to be resolved by the runtime loader. This option
+disallows such undefined symbols if they come from regular object
+files. The switch @samp{--no-allow-shlib-undefined} controls the
+behaviour for shared objects being linked into the shared library.
+
+@kindex --allow-multiple-definition
+@kindex -z muldefs
+@item --allow-multiple-definition
+@itemx -z muldefs
+Normally when a symbol is defined multiple times, the linker will
+report a fatal error. These options allow multiple definitions and the
+first definition will be used.
@kindex --allow-shlib-undefined
+@kindex --no-allow-shlib-undefined
@item --allow-shlib-undefined
-Allow undefined symbols in shared objects even when --no-undefined is
-set. The net result will be that undefined symbols in regular objects
-will still trigger an error, but undefined symbols in shared objects
-will be ignored. The implementation of no_undefined makes the
-assumption that the runtime linker will choke on undefined symbols.
-However there is at least one system (BeOS) where undefined symbols in
-shared libraries is normal since the kernel patches them at load time to
-select which function is most appropriate for the current architecture.
-I.E. dynamically select an appropriate memset function. Apparently it
-is also normal for HPPA shared libraries to have undefined symbols.
+@itemx --no-allow-shlib-undefined
+Allow (the default) or disallow undefined symbols in shared objects.
+The setting of this switch overrides @samp {--no-undefined} where
+shared objects are concerned. Thus if @samp {--no-undefined} is set
+but @samp {--no-allow-shlib-undefined} is not, the net result will be
+that undefined symbols in regular object files will trigger an error,
+but undefined symbols in shared objects will be ignored.
+
+The reason that @samp{--allow-shlib-undefined} is the default is that
+the shared object being specified at link time may not be the same one
+that is available at load time, so the symbols might actually be
+resolvable at load time. Plus there are some systems, (eg BeOS) where
+undefined symbols in shared libraries is normal since the kernel
+patches them at load time to select which function is most appropriate
+for the current architecture. eg. to dynamically select an appropriate
+memset function. Apparently it is also normal for HPPA shared
+libraries to have undefined symbols.
+
+@kindex --no-undefined-version
+@item --no-undefined-version
+Normally when a symbol has an undefined version, the linker will ignore
+it. This option disallows symbols with undefined version and a fatal error
+will be issued instead.
@kindex --no-warn-mismatch
@item --no-warn-mismatch
-Normally @code{ld} will give an error if you try to link together input
+Normally @command{ld} will give an error if you try to link together input
files that are mismatched for some reason, perhaps because they have
been compiled for different processors or for different endiannesses.
-This option tells @code{ld} that it should silently permit such possible
+This option tells @command{ld} that it should silently permit such possible
errors. This option should only be used with care, in cases when you
have taken some special action that ensures that the linker errors are
inappropriate.
@kindex --no-whole-archive
@item --no-whole-archive
-Turn off the effect of the @code{--whole-archive} option for subsequent
+Turn off the effect of the @option{--whole-archive} option for subsequent
archive files.
@cindex output file after errors
errors during the link process; it exits without writing an output file
when it issues any error whatsoever.
+@kindex -nostdlib
+@item -nostdlib
+Only search library directories explicitly specified on the
+command line. Library directories specified in linker scripts
+(including linker scripts specified on the command line) are ignored.
+
@ifclear SingleFormat
@kindex --oformat
@item --oformat @var{output-format}
-@code{ld} may be configured to support more than one kind of object
-file. If your @code{ld} is configured this way, you can use the
+@command{ld} may be configured to support more than one kind of object
+file. If your @command{ld} is configured this way, you can use the
@samp{--oformat} option to specify the binary format for the output
-object file. Even when @code{ld} is configured to support alternative
-object formats, you don't usually need to specify this, as @code{ld}
+object file. Even when @command{ld} is configured to support alternative
+object formats, you don't usually need to specify this, as @command{ld}
should be configured to produce as a default output format the most
usual format on each machine. @var{output-format} is a text string, the
name of a particular format supported by the BFD libraries. (You can
This option is only supported on a few targets.
@end ifset
@ifset H8300
-@xref{H8/300,,@code{ld} and the H8/300}.
+@xref{H8/300,,@command{ld} and the H8/300}.
@end ifset
@ifset I960
-@xref{i960,, @code{ld} and the Intel 960 family}.
+@xref{i960,, @command{ld} and the Intel 960 family}.
@end ifset
@cindex runtime library search path
@kindex -rpath
Add a directory to the runtime library search path. This is used when
-linking an ELF executable with shared objects. All @code{-rpath}
+linking an ELF executable with shared objects. All @option{-rpath}
arguments are concatenated and passed to the runtime linker, which uses
-them to locate shared objects at runtime. The @code{-rpath} option is
+them to locate shared objects at runtime. The @option{-rpath} option is
also used when locating shared objects which are needed by shared
objects explicitly included in the link; see the description of the
-@code{-rpath-link} option. If @code{-rpath} is not used when linking an
+@option{-rpath-link} option. If @option{-rpath} is not used when linking an
ELF executable, the contents of the environment variable
@code{LD_RUN_PATH} will be used if it is defined.
-The @code{-rpath} option may also be used on SunOS. By default, on
+The @option{-rpath} option may also be used on SunOS. By default, on
SunOS, the linker will form a runtime search patch out of all the
-@code{-L} options it is given. If a @code{-rpath} option is used, the
-runtime search path will be formed exclusively using the @code{-rpath}
-options, ignoring the @code{-L} options. This can be useful when using
-gcc, which adds many @code{-L} options which may be on NFS mounted
+@option{-L} options it is given. If a @option{-rpath} option is used, the
+runtime search path will be formed exclusively using the @option{-rpath}
+options, ignoring the @option{-L} options. This can be useful when using
+gcc, which adds many @option{-L} options which may be on NFS mounted
filesystems.
-For compatibility with other ELF linkers, if the @code{-R} option is
+For compatibility with other ELF linkers, if the @option{-R} option is
followed by a directory name, rather than a file name, it is treated as
-the @code{-rpath} option.
+the @option{-rpath} option.
@end ifset
@ifset GENERIC
When the linker encounters such a dependency when doing a non-shared,
non-relocatable link, it will automatically try to locate the required
shared library and include it in the link, if it is not included
-explicitly. In such a case, the @code{-rpath-link} option
+explicitly. In such a case, the @option{-rpath-link} option
specifies the first set of directories to search. The
-@code{-rpath-link} option may specify a sequence of directory names
+@option{-rpath-link} option may specify a sequence of directory names
either by specifying a list of names separated by colons, or by
appearing multiple times.
libraries.
@enumerate
@item
-Any directories specified by @code{-rpath-link} options.
+Any directories specified by @option{-rpath-link} options.
@item
-Any directories specified by @code{-rpath} options. The difference
-between @code{-rpath} and @code{-rpath-link} is that directories
-specified by @code{-rpath} options are included in the executable and
-used at runtime, whereas the @code{-rpath-link} option is only effective
+Any directories specified by @option{-rpath} options. The difference
+between @option{-rpath} and @option{-rpath-link} is that directories
+specified by @option{-rpath} options are included in the executable and
+used at runtime, whereas the @option{-rpath-link} option is only effective
at link time. It is for the native linker only.
@item
-On an ELF system, if the @code{-rpath} and @code{rpath-link} options
+On an ELF system, if the @option{-rpath} and @code{rpath-link} options
were not used, search the contents of the environment variable
@code{LD_RUN_PATH}. It is for the native linker only.
@item
-On SunOS, if the @code{-rpath} option was not used, search any
-directories specified using @code{-L} options.
+On SunOS, if the @option{-rpath} option was not used, search any
+directories specified using @option{-L} options.
@item
For a native linker, the contents of the environment variable
@code{LD_LIBRARY_PATH}.
@cindex shared libraries
Create a shared library. This is currently only supported on ELF, XCOFF
and SunOS platforms. On SunOS, the linker will automatically create a
-shared library if the @code{-e} option is not used and there are
+shared library if the @option{-e} option is not used and there are
undefined symbols in the link.
@item --sort-common
@kindex --sort-common
-This option tells @code{ld} to sort the common symbols by size when it
+This option tells @command{ld} to sort the common symbols by size when it
places them in the appropriate output sections. First come all the one
-byte symbols, then all the two bytes, then all the four bytes, and then
+byte symbols, then all the two byte, then all the four byte, and then
everything else. This is to prevent gaps between symbols due to
alignment constraints.
@kindex --split-by-file
@item --split-by-file [@var{size}]
-Similar to @code{--split-by-reloc} but creates a new output section for
+Similar to @option{--split-by-reloc} but creates a new output section for
each input file when @var{size} is reached. @var{size} defaults to a
size of 1 if not given.
@kindex --traditional-format
@cindex traditional format
@item --traditional-format
-For some targets, the output of @code{ld} is different in some ways from
-the output of some existing linker. This switch requests @code{ld} to
+For some targets, the output of @command{ld} is different in some ways from
+the output of some existing linker. This switch requests @command{ld} to
use the traditional format instead.
@cindex dbx
-For example, on SunOS, @code{ld} combines duplicate entries in the
+For example, on SunOS, @command{ld} combines duplicate entries in the
symbol string table. This can reduce the size of an output file with
full debugging information by over 30 percent. Unfortunately, the SunOS
@code{dbx} program can not read the resulting program (@code{gdb} has no
-trouble). The @samp{--traditional-format} switch tells @code{ld} to not
+trouble). The @samp{--traditional-format} switch tells @command{ld} to not
combine duplicate entries.
@kindex --section-start @var{sectionname}=@var{org}
@cindex verbose
@item --dll-verbose
@itemx --verbose
-Display the version number for @code{ld} and list the linker emulations
+Display the version number for @command{ld} and list the linker emulations
supported. Display which input files can and cannot be opened. Display
-the linker script if using a default builtin script.
+the linker script being used by the linker.
@kindex --version-script=@var{version-scriptfile}
@cindex version script, symbol versions
@cindex including an entire archive
@item --whole-archive
For each archive mentioned on the command line after the
-@code{--whole-archive} option, include every object file in the archive
+@option{--whole-archive} option, include every object file in the archive
in the link, rather than searching the archive for the required object
files. This is normally used to turn an archive file into a shared
library, forcing every object to be included in the resulting shared
library. This option may be used more than once.
Two notes when using this option from gcc: First, gcc doesn't know
-about this option, so you have to use @code{-Wl,-whole-archive}.
-Second, don't forget to use @code{-Wl,-no-whole-archive} after your
+about this option, so you have to use @option{-Wl,-whole-archive}.
+Second, don't forget to use @option{-Wl,-no-whole-archive} after your
list of archives, because gcc will add its own list of archives to
your link and you may not want this flag to affect those as well.
@}
@end smallexample
-If you link other code with this file using @code{--wrap malloc}, then
+If you link other code with this file using @option{--wrap malloc}, then
all calls to @code{malloc} will call the function @code{__wrap_malloc}
instead. The call to @code{__real_malloc} in @code{__wrap_malloc} will
call the real @code{malloc} function.
You may wish to provide a @code{__real_malloc} function as well, so that
-links without the @code{--wrap} option will succeed. If you do this,
+links without the @option{--wrap} option will succeed. If you do this,
you should not put the definition of @code{__real_malloc} in the same
file as @code{__wrap_malloc}; if you do, the assembler may resolve the
call before the linker has a chance to wrap it to @code{malloc}.
@itemx --disable-new-dtags
This linker can create the new dynamic tags in ELF. But the older ELF
systems may not understand them. If you specify
-@code{--enable-new-dtags}, the dynamic tags will be created as needed.
-If you specify @code{--disable-new-dtags}, no new dynamic tags will be
+@option{--enable-new-dtags}, the dynamic tags will be created as needed.
+If you specify @option{--disable-new-dtags}, no new dynamic tags will be
created. By default, the new dynamic tags are not created. Note that
those options are only available for ELF systems.
@c man begin OPTIONS
-The i386 PE linker supports the @code{-shared} option, which causes
+The i386 PE linker supports the @option{-shared} option, which causes
the output to be a dynamically linked library (DLL) instead of a
normal executable. You should name the output @code{*.dll} when you
use this option. In addition, the linker fully supports the standard
PE target. Options that take values may be separated from their
values by either a space or an equals sign.
-@table @code
+@table @gcctabopt
@kindex --add-stdcall-alias
@item --add-stdcall-alias
@kindex --dll
@item --dll
Create a DLL instead of a regular executable. You may also use
-@code{-shared} or specify a @code{LIBRARY} in a given @code{.def}
+@option{-shared} or specify a @code{LIBRARY} in a given @code{.def}
file.
@kindex --enable-stdcall-fixup
to the function @code{_bar}. When the linker does this, it prints a
warning, since it normally should have failed to link, but sometimes
import libraries generated from third-party dlls may need this feature
-to be usable. If you specify @code{--enable-stdcall-fixup}, this
+to be usable. If you specify @option{--enable-stdcall-fixup}, this
feature is fully enabled and warnings are not printed. If you specify
-@code{--disable-stdcall-fixup}, this feature is disabled and such
+@option{--disable-stdcall-fixup}, this feature is disabled and such
mismatches are considered to be errors.
@cindex DLLs, creating
explicitly exported via DEF files or implicitly exported via function
attributes, the default is to not export anything else unless this
option is given. Note that the symbols @code{DllMain@@12},
-@code{DllEntryPoint@@0}, and @code{impure_ptr} will not be automatically
-exported.
+@code{DllEntryPoint@@0}, @code{DllMainCRTStartup@@12}, and
+@code{impure_ptr} will not be automatically
+exported. Also, symbols imported from other DLLs will not be
+re-exported, nor will symbols specifying the DLL's internal layout
+such as those beginning with @code{_head_} or ending with
+@code{_iname}. In addition, no symbols from @code{libgcc},
+@code{libstd++}, @code{libmingw32}, or @code{crtX.o} will be exported.
+Symbols whose names begin with @code{__rtti_} or @code{__builtin_} will
+not be exported, to help with C++ DLLs. Finally, there is an
+extensive list of cygwin-private symbols that are not exported
+(obviously, this applies on when building DLLs for cygwin targets).
+These cygwin-excludes are: @code{_cygwin_dll_entry@@12},
+@code{_cygwin_crt0_common@@8}, @code{_cygwin_noncygwin_dll_entry@@12},
+@code{_fmode}, @code{_impure_ptr}, @code{cygwin_attach_dll},
+@code{cygwin_premain0}, @code{cygwin_premain1}, @code{cygwin_premain2},
+@code{cygwin_premain3}, and @code{environ}.
@kindex --exclude-symbols
@item --exclude-symbols @var{symbol},@var{symbol},...
Specifies a list of symbols which should not be automatically
exported. The symbol names may be delimited by commas or colons.
+@kindex --exclude-libs
+@item --exclude-libs @var{lib},@var{lib},...
+Specifies a list of archive libraries from which symbols should not be automatically
+exported. The library names may be delimited by commas or colons. Specifying
+@code{--exclude-libs ALL} excludes symbols in all archive libraries from
+automatic export. Symbols explicitly listed in a .def file are still exported,
+regardless of this option.
+
@kindex --file-alignment
@item --file-alignment
Specify the file alignment. Sections in the file will always begin at
library with @code{dlltool} or may be used as a reference to
automatically or implicitly exported symbols.
+@cindex DLLs, creating
+@kindex --out-implib
+@item --out-implib @var{file}
+The linker will create the file @var{file} which will contain an
+import lib corresponding to the DLL the linker is generating. This
+import lib (which should be called @code{*.dll.a} or @code{*.a}
+may be used to link clients against the generated DLL; this behavior
+makes it possible to skip a separate @code{dlltool} import library
+creation step.
+
+@kindex --enable-auto-image-base
+@item --enable-auto-image-base
+Automatically choose the image base for DLLs, unless one is specified
+using the @code{--image-base} argument. By using a hash generated
+from the dllname to create unique image bases for each DLL, in-memory
+collisions and relocations which can delay program execution are
+avoided.
+
+@kindex --disable-auto-image-base
+@item --disable-auto-image-base
+Do not automatically generate a unique image base. If there is no
+user-specified image base (@code{--image-base}) then use the platform
+default.
+
+@cindex DLLs, linking to
+@kindex --dll-search-prefix
+@item --dll-search-prefix @var{string}
+When linking dynamically to a dll without an import library,
+search for @code{<string><basename>.dll} in preference to
+@code{lib<basename>.dll}. This behavior allows easy distinction
+between DLLs built for the various "subplatforms": native, cygwin,
+uwin, pw, etc. For instance, cygwin DLLs typically use
+@code{--dll-search-prefix=cyg}.
+
+@kindex --enable-auto-import
+@item --enable-auto-import
+Do sophisticated linking of @code{_symbol} to @code{__imp__symbol} for
+DATA imports from DLLs, and create the necessary thunking symbols when
+building the import libraries with those DATA exports. This generally
+will 'just work' -- but sometimes you may see this message:
+
+"variable '<var>' can't be auto-imported. Please read the
+documentation for ld's @code{--enable-auto-import} for details."
+
+This message occurs when some (sub)expression accesses an address
+ultimately given by the sum of two constants (Win32 import tables only
+allow one). Instances where this may occur include accesses to member
+fields of struct variables imported from a DLL, as well as using a
+constant index into an array variable imported from a DLL. Any
+multiword variable (arrays, structs, long long, etc) may trigger
+this error condition. However, regardless of the exact data type
+of the offending exported variable, ld will always detect it, issue
+the warning, and exit.
+
+There are several ways to address this difficulty, regardless of the
+data type of the exported variable:
+
+One way is to use --enable-runtime-pseudo-reloc switch. This leaves the task
+of adjusting references in your client code for runtime environment, so
+this method works only when runtime environtment supports this feature.
+
+A second solution is to force one of the 'constants' to be a variable --
+that is, unknown and un-optimizable at compile time. For arrays,
+there are two possibilities: a) make the indexee (the array's address)
+a variable, or b) make the 'constant' index a variable. Thus:
+
+@example
+extern type extern_array[];
+extern_array[1] -->
+ @{ volatile type *t=extern_array; t[1] @}
+@end example
+
+or
+
+@example
+extern type extern_array[];
+extern_array[1] -->
+ @{ volatile int t=1; extern_array[t] @}
+@end example
+
+For structs (and most other multiword data types) the only option
+is to make the struct itself (or the long long, or the ...) variable:
+
+@example
+extern struct s extern_struct;
+extern_struct.field -->
+ @{ volatile struct s *t=&extern_struct; t->field @}
+@end example
+
+or
+
+@example
+extern long long extern_ll;
+extern_ll -->
+ @{ volatile long long * local_ll=&extern_ll; *local_ll @}
+@end example
+
+A third method of dealing with this difficulty is to abandon
+'auto-import' for the offending symbol and mark it with
+@code{__declspec(dllimport)}. However, in practice that
+requires using compile-time #defines to indicate whether you are
+building a DLL, building client code that will link to the DLL, or
+merely building/linking to a static library. In making the choice
+between the various methods of resolving the 'direct address with
+constant offset' problem, you should consider typical real-world usage:
+
+Original:
+@example
+--foo.h
+extern int arr[];
+--foo.c
+#include "foo.h"
+void main(int argc, char **argv)@{
+ printf("%d\n",arr[1]);
+@}
+@end example
+
+Solution 1:
+@example
+--foo.h
+extern int arr[];
+--foo.c
+#include "foo.h"
+void main(int argc, char **argv)@{
+ /* This workaround is for win32 and cygwin; do not "optimize" */
+ volatile int *parr = arr;
+ printf("%d\n",parr[1]);
+@}
+@end example
+
+Solution 2:
+@example
+--foo.h
+/* Note: auto-export is assumed (no __declspec(dllexport)) */
+#if (defined(_WIN32) || defined(__CYGWIN__)) && \
+ !(defined(FOO_BUILD_DLL) || defined(FOO_STATIC))
+#define FOO_IMPORT __declspec(dllimport)
+#else
+#define FOO_IMPORT
+#endif
+extern FOO_IMPORT int arr[];
+--foo.c
+#include "foo.h"
+void main(int argc, char **argv)@{
+ printf("%d\n",arr[1]);
+@}
+@end example
+
+A fourth way to avoid this problem is to re-code your
+library to use a functional interface rather than a data interface
+for the offending variables (e.g. set_foo() and get_foo() accessor
+functions).
+
+@kindex --disable-auto-import
+@item --disable-auto-import
+Do not attempt to do sophisticalted linking of @code{_symbol} to
+@code{__imp__symbol} for DATA imports from DLLs.
+
+@kindex --enable-runtime-pseudo-reloc
+@item --enable-runtime-pseudo-reloc
+If your code contains expressions described in --enable-auto-import section,
+that is, DATA imports from DLL with non-zero offset, this switch will create
+a vector of 'runtime pseudo relocations' which can be used by runtime
+environment to adjust references to such data in your client code.
+
+@kindex --disable-runtime-pseudo-reloc
+@item --disable-runtime-pseudo-reloc
+Do not create pseudo relocations for non-zero offset DATA imports from
+DLLs. This is the default.
+
+@kindex --enable-extra-pe-debug
+@item --enable-extra-pe-debug
+Show additional debug info related to auto-import symbol thunking.
+
@kindex --section-alignment
@item --section-alignment
Sets the section alignment. Sections in memory will always begin at
@item --stack @var{reserve}
@itemx --stack @var{reserve},@var{commit}
Specify the amount of memory to reserve (and optionally commit) to be
-used as stack for this program. The default is 32Mb reserved, 4K
+used as stack for this program. The default is 2Mb reserved, 4K
committed.
@kindex --subsystem
@c man begin ENVIRONMENT
-You can change the behavior of @code{ld} with the environment variables
+You can change the behavior of @command{ld} with the environment variables
@code{GNUTARGET}, @code{LDEMULATION}, and @code{COLLECT_NO_DEMANGLE}.
@kindex GNUTARGET
@code{GNUTARGET} determines the input-file object format if you don't
use @samp{-b} (or its synonym @samp{--format}). Its value should be one
of the BFD names for an input format (@pxref{BFD}). If there is no
-@code{GNUTARGET} in the environment, @code{ld} uses the natural format
+@code{GNUTARGET} in the environment, @command{ld} uses the natural format
of the target. If @code{GNUTARGET} is set to @code{default} then BFD
attempts to discover the input format by examining binary input files;
this method often succeeds, but there are potential ambiguities, since
@cindex including a linker script
Include the linker script @var{filename} at this point. The file will
be searched for in the current directory, and in any directory specified
-with the @code{-L} option. You can nest calls to @code{INCLUDE} up to
+with the @option{-L} option. You can nest calls to @code{INCLUDE} up to
10 levels deep.
@item INPUT(@var{file}, @var{file}, @dots{})
search path. See the description of @samp{-L} in @ref{Options,,Command
Line Options}.
-If you use @samp{INPUT (-l@var{file})}, @code{ld} will transform the
+If you use @samp{INPUT (-l@var{file})}, @command{ld} will transform the
name to @code{lib@var{file}.a}, as with the command line argument
@samp{-l}.
@cindex archive search path in linker script
@cindex search path in linker script
The @code{SEARCH_DIR} command adds @var{path} to the list of paths where
-@code{ld} looks for archive libraries. Using
+@command{ld} looks for archive libraries. Using
@code{SEARCH_DIR(@var{path})} is exactly like using @samp{-L @var{path}}
on the command line (@pxref{Options,,Command Line Options}). If both
are used, then the linker will search both paths. Paths specified using
@cindex output file format in linker script
The @code{OUTPUT_FORMAT} command names the BFD format to use for the
output file (@pxref{BFD}). Using @code{OUTPUT_FORMAT(@var{bfdname})} is
-exactly like using @samp{-oformat @var{bfdname}} on the command line
+exactly like using @samp{--oformat @var{bfdname}} on the command line
(@pxref{Options,,Command Line Options}). If both are used, the command
line option takes precedence.
@kindex FORCE_COMMON_ALLOCATION
@cindex common allocation in linker script
This command has the same effect as the @samp{-d} command-line option:
-to make @code{ld} assign space to common symbols even if a relocatable
+to make @command{ld} assign space to common symbols even if a relocatable
output file is specified (@samp{-r}).
+@item INHIBIT_COMMON_ALLOCATION
+@kindex INHIBIT_COMMON_ALLOCATION
+@cindex common allocation in linker script
+This command has the same effect as the @samp{--no-define-common}
+command-line option: to make @code{ld} omit the assignment of addresses
+to common symbols even for a non-relocatable output file.
+
@item NOCROSSREFS(@var{section} @var{section} @dots{})
@kindex NOCROSSREFS(@var{sections})
@cindex cross references
-This command may be used to tell @code{ld} to issue an error about any
+This command may be used to tell @command{ld} to issue an error about any
references among certain output sections.
In certain types of programs, particularly on embedded systems when
a function defined in the other section.
The @code{NOCROSSREFS} command takes a list of output section names. If
-@code{ld} detects any cross references between the sections, it reports
+@command{ld} detects any cross references between the sections, it reports
an error and returns a non-zero exit status. Note that the
@code{NOCROSSREFS} command uses output section names, not input section
names.
@noindent
The difference between these is the order in which the @samp{.text} and
@samp{.rdata} input sections will appear in the output section. In the
-first example, they will be intermingled. In the second example, all
+first example, they will be intermingled, appearing in the same order as
+they are found in the linker input. In the second example, all
@samp{.text} input sections will appear first, followed by all
@samp{.rdata} input sections.
current section. It is followed by an expression in parentheses. Any
otherwise unspecified regions of memory within the section (for example,
gaps left due to the required alignment of input sections) are filled
-with the two least significant bytes of the expression, repeated as
+with the value of the expression, repeated as
necessary. A @code{FILL} statement covers memory locations after the
point at which it occurs in the section definition; by including more
than one @code{FILL} statement, you can have different fill patterns in
different parts of an output section.
This example shows how to fill unspecified regions of memory with the
-value @samp{0x9090}:
+value @samp{0x90}:
@smallexample
-FILL(0x9090)
+FILL(0x90909090)
@end smallexample
The @code{FILL} command is similar to the @samp{=@var{fillexp}} output
-section attribute (@pxref{Output Section Fill}), but it only affects the
+section attribute, but it only affects the
part of the section following the @code{FILL} command, rather than the
entire section. If both are used, the @code{FILL} command takes
-precedence.
+precedence. @xref{Output Section Fill}, for details on the fill
+expression.
@node Output Section Keywords
@subsection Output section keywords
@samp{=@var{fillexp}}. @var{fillexp} is an expression
(@pxref{Expressions}). Any otherwise unspecified regions of memory
within the output section (for example, gaps left due to the required
-alignment of input sections) will be filled with the two least
-significant bytes of the value, repeated as necessary.
+alignment of input sections) will be filled with the value, repeated as
+necessary. If the fill expression is a simple hex number, ie. a string
+of hex digit starting with @samp{0x} and without a trailing @samp{k} or @samp{M}, then
+an arbitrarily long sequence of hex digits can be used to specify the
+fill pattern; Leading zeros become part of the pattern too. For all
+other cases, including extra parentheses or a unary @code{+}, the fill
+pattern is the four least significant bytes of the value of the
+expression. In all cases, the number is big-endian.
You can also change the fill value with a @code{FILL} command in the
-output section commands; see @ref{Output Section Data}.
+output section commands; (@pxref{Output Section Data}).
Here is a simple example:
@smallexample
@group
-SECTIONS @{ .text : @{ *(.text) @} =0x9090 @}
+SECTIONS @{ .text : @{ *(.text) @} =0x90909090 @}
@end group
@end smallexample
version node defined is @samp{VERS_1.1}; it has no other dependencies.
The script binds the symbol @samp{foo1} to @samp{VERS_1.1}. It reduces
a number of symbols to local scope so that they are not visible outside
-of the shared library.
+of the shared library; this is done using wildcard patterns, so that any
+symbol whose name begins with @samp{old}, @samp{original}, or @samp{new}
+is matched. The wildcard patterns available are the same as those used
+in the shell when matching filenames (also known as ``globbing'').
Next, the version script defines node @samp{VERS_1.2}. This node
depends upon @samp{VERS_1.1}. The script binds the symbol @samp{foo2}
When the linker finds a symbol defined in a library which is not
specifically bound to a version node, it will effectively bind it to an
unspecified base version of the library. You can bind all otherwise
-unspecified symbols to a given version node by using @samp{global: *}
+unspecified symbols to a given version node by using @samp{global: *;}
somewhere in the version script.
The names of the version nodes have no specific meaning other than what
could just as well have appeared in between @samp{1.1} and @samp{1.2}.
However, this would be a confusing way to write a version script.
+Node name can be omited, provided it is the only version node
+in the version script. Such version script doesn't assign any versions to
+symbols, only selects which symbols will be globally visible out and which
+won't.
+
+@smallexample
+@{ global: foo; bar; local: *; @};
+@end smallexample
+
When you link an application against a shared library that has versioned
symbols, the application itself knows which version of each symbol it
requires, and it also knows which version nodes it needs from each
in the C source file. This renames the function @samp{original_foo} to
be an alias for @samp{foo} bound to the version node @samp{VERS_1.1}.
The @samp{local:} directive can be used to prevent the symbol
-@samp{original_foo} from being exported.
+@samp{original_foo} from being exported. A @samp{.symver} directive
+takes precedence over a version script.
The second GNU extension is to allow multiple versions of the same
function to appear in a given shared library. In this way you can make
file2(.text)
. += 1000;
file3(.text)
- @} = 0x1234;
+ @} = 0x12345678;
@}
@end smallexample
@noindent
located at the beginning of the output section @samp{output}. It is
followed by a 1000 byte gap. Then the @samp{.text} section from
@file{file2} appears, also with a 1000 byte gap following before the
-@samp{.text} section from @file{file3}. The notation @samp{= 0x1234}
+@samp{.text} section from @file{file3}. The notation @samp{= 0x12345678}
specifies what data to write in the gaps (@pxref{Output Section Fill}).
@cindex dot inside sections
Note: @code{.} actually refers to the byte offset from the start of the
current containing object. Normally this is the @code{SECTIONS}
-statement, whoes start address is 0, hence @code{.} can be used as an
+statement, whose start address is 0, hence @code{.} can be used as an
absolute address. If @code{.} is used inside a section description
however, it refers to the byte offset from the start of that section,
not an absolute address. Thus in a script like this:
@cindex round up location counter
@cindex align location counter
Return the location counter (@code{.}) aligned to the next @var{exp}
-boundary. @var{exp} must be an expression whose value is a power of
-two. This is equivalent to
-@smallexample
-(. + @var{exp} - 1) & ~(@var{exp} - 1)
-@end smallexample
-
+boundary.
@code{ALIGN} doesn't change the value of the location counter---it just
does arithmetic on it. Here is an example which aligns the output
@code{.data} section to the next @code{0x2000} byte boundary after the
scripts. It is most often seen when setting the address of an output
section.
+@item DATA_SEGMENT_ALIGN(@var{maxpagesize}, @var{commonpagesize})
+@kindex DATA_SEGMENT_ALIGN(@var{maxpagesize}, @var{commonpagesize})
+This is equivalent to either
+@smallexample
+(ALIGN(@var{maxpagesize}) + (. & (@var{maxpagesize} - 1)))
+@end smallexample
+or
+@smallexample
+(ALIGN(@var{maxpagesize}) + (. & (@var{maxpagesize} - @var{commonpagesize})))
+@end smallexample
+@noindent
+depending on whether the latter uses fewer @var{commonpagesize} sized pages
+for the data segment (area between the result of this expression and
+@code{DATA_SEGMENT_END}) than the former or not.
+If the latter form is used, it means @var{commonpagesize} bytes of runtime
+memory will be saved at the expense of up to @var{commonpagesize} wasted
+bytes in the on-disk file.
+
+This expression can only be used directly in @code{SECTIONS} commands, not in
+any output section descriptions and only once in the linker script.
+@var{commonpagesize} should be less or equal to @var{maxpagesize} and should
+be the system page size the object wants to be optimized for (while still
+working on system page sizes up to @var{maxpagesize}).
+
+@noindent
+Example:
+@smallexample
+ . = DATA_SEGMENT_ALIGN(0x10000, 0x2000);
+@end smallexample
+
+@item DATA_SEGMENT_END(@var{exp})
+@kindex DATA_SEGMENT_END(@var{exp})
+This defines the end of data segment for @code{DATA_SEGMENT_ALIGN}
+evaluation purposes.
+
+@smallexample
+ . = DATA_SEGMENT_END(.);
+@end smallexample
+
@item DEFINED(@var{symbol})
@kindex DEFINED(@var{symbol})
@cindex symbol defaults
@chapter Machine Dependent Features
@cindex machine dependencies
-@code{ld} has additional features on some platforms; the following
-sections describe them. Machines where @code{ld} has no additional
+@command{ld} has additional features on some platforms; the following
+sections describe them. Machines where @command{ld} has no additional
functionality are not listed.
@menu
* i960:: @code{ld} and the Intel 960 family
* ARM:: @code{ld} and the ARM family
* HPPA ELF32:: @code{ld} and HPPA 32-bit ELF
+@ifset MMIX
+* MMIX:: @code{ld} and MMIX
+@end ifset
+@ifset MSP430
+* MSP430:: @code{ld} and MSP430
+@end ifset
@ifset TICOFF
-* TI COFF:: @code{ld} and TI COFF
+* TI COFF:: @command{ld} and TI COFF
+@end ifset
+@ifset WIN32
+* WIN32:: @command{ld} and WIN32 (cygwin/mingw)
@end ifset
@end menu
@end ifset
@end ifclear
@node H8/300
-@section @code{ld} and the H8/300
+@section @command{ld} and the H8/300
@cindex H8/300 support
-For the H8/300, @code{ld} can perform these global optimizations when
+For the H8/300, @command{ld} can perform these global optimizations when
you specify the @samp{--relax} command-line option.
@table @emph
@cindex relaxing on H8/300
@item relaxing address modes
-@code{ld} finds all @code{jsr} and @code{jmp} instructions whose
+@command{ld} finds all @code{jsr} and @code{jmp} instructions whose
targets are within eight bits, and turns them into eight-bit
program-counter relative @code{bsr} and @code{bra} instructions,
respectively.
@cindex synthesizing on H8/300
@item synthesizing instructions
@c FIXME: specifically mov.b, or any mov instructions really?
-@code{ld} finds all @code{mov.b} instructions which use the
+@command{ld} finds all @code{mov.b} instructions which use the
sixteen-bit absolute address form, but refer to the top
page of memory, and changes them to use the eight-bit address form.
(That is: the linker turns @samp{mov.b @code{@@}@var{aa}:16} into
@end ifclear
@end ifset
+@ifset WIN32
+@ifclear GENERIC
+@raisesections
+@end ifclear
+
+@node WIN32
+@section @command{ld} and WIN32 (cygwin/mingw)
+
+This section describes some of the win32 specific @command{ld} issues.
+See @ref{Options,,Command Line Options} for detailed decription of the
+command line options mentioned here.
+
+@table @emph
+@cindex import libraries
+@item import libraries
+The standard Windows linker creates and uses so-called import
+libraries, which contains information for linking to dll's. They are
+regular static archives and are handled as any other static
+archive. The cygwin and mingw ports of @command{ld} have specific
+support for creating such libraries provided with the
+@samp{--out-implib} command line option.
+
+@item exporting DLL symbols
+@cindex exporting DLL symbols
+The cygwin/mingw @command{ld} has several ways to export symbols for dll's.
+
+@table @emph
+@item using auto-export functionality
+@cindex using auto-export functionality
+By default @command{ld} exports symbols with the auto-export functionality,
+which is controlled by the following command line options:
+
+@itemize
+@item --export-all-symbols [This is the default]
+@item --exclude-symbols
+@item --exclude-libs
+@end itemize
+
+If, however, @samp{--export-all-symbols} is not given explicitly on the
+command line, then the default auto-export behavior will be @emph{disabled}
+if either of the following are true:
+
+@itemize
+@item A DEF file is used.
+@item Any symbol in any object file was marked with the __declspec(dllexport) attribute.
+@end itemize
+
+@item using a DEF file
+@cindex using a DEF file
+Another way of exporting symbols is using a DEF file. A DEF file is
+an ASCII file containing definitions of symbols which should be
+exported when a dll is created. Usually it is named @samp{<dll
+name>.def} and is added as any other object file to the linker's
+command line. The file's name must end in @samp{.def} or @samp{.DEF}.
+
+@example
+gcc -o <output> <objectfiles> <dll name>.def
+@end example
+
+Using a DEF file turns off the normal auto-export behavior, unless the
+@samp{--export-all-symbols} option is also used.
+
+Here is an example of a DEF file for a shared library called @samp{xyz.dll}:
+
+@example
+LIBRARY "xyz.dll" BASE=0x10000000
+
+EXPORTS
+foo
+bar
+_bar = bar
+@end example
+
+This example defines a base address and three symbols. The third
+symbol is an alias for the second. For the complete format
+specification see ld/deffilep.y in the binutils sources.
+
+@cindex creating a DEF file
+While linking a shared dll, @command{ld} is able to create a DEF file
+with the @samp{--output-def <file>} command line option.
+
+@item Using decorations
+@cindex Using decorations
+Another way of marking symbols for export is to modify the source code
+itself, so that when building the DLL each symbol to be exported is
+declared as:
+
+@example
+__declspec(dllexport) int a_variable
+__declspec(dllexport) void a_function(int with_args)
+@end example
+
+All such symbols will be exported from the DLL. If, however,
+any of the object files in the DLL contain symbols decorated in
+this way, then the normal auto-export behavior is disabled, unless
+the @samp{--export-all-symbols} option is also used.
+
+Note that object files that wish to access these symbols must @emph{not}
+decorate them with dllexport. Instead, they should use dllimport,
+instead:
+
+@example
+__declspec(dllimport) int a_variable
+__declspec(dllimport) void a_function(int with_args)
+@end example
+
+This complicates the structure of library header files, because
+when included by the library itself the header must declare the
+variables and functions as dllexport, but when included by client
+code the header must declare them as dllimport. There are a number
+of idioms that are typically used to do this; often client code can
+omit the __declspec() declaration completely. See
+@samp{--enable-auto-import} and @samp{automatic data imports} for more
+imformation.
+@end table
+
+@cindex automatic data imports
+@item automatic data imports
+The standard Windows dll format supports data imports from dlls only
+by adding special decorations (dllimport/dllexport), which let the
+compiler produce specific assembler instructions to deal with this
+issue. This increases the effort necessary to port existing Un*x
+code to these platforms, especially for large
+c++ libraries and applications. The auto-import feature, which was
+initially provided by Paul Sokolovsky, allows one to omit the
+decorations to archieve a behavior that conforms to that on POSIX/Un*x
+platforms. This feature is enabled with the @samp{--enable-auto-import}
+command-line option, although it is enabled by default on cygwin/mingw.
+The @samp{--enable-auto-import} option itself now serves mainly to
+suppress any warnings that are ordinarily emitted when linked objects
+trigger the feature's use.
+
+auto-import of variables does not always work flawlessly without
+additional assistance. Sometimes, you will see this message
+
+"variable '<var>' can't be auto-imported. Please read the
+documentation for ld's @code{--enable-auto-import} for details."
+
+The @samp{--enable-auto-import} documentation explains why this error
+occurs, and several methods that can be used to overcome this difficulty.
+One of these methods is the @emph{runtime pseudo-relocs} feature, described
+below.
+
+@cindex runtime pseudo-relocation
+For complex variables imported from DLLs (such as structs or classes),
+object files typically contain a base address for the variable and an
+offset (@emph{addend}) within the variable--to specify a particular
+field or public member, for instance. Unfortunately, the runtime loader used
+in win32 environments is incapable of fixing these references at runtime
+without the additional information supplied by dllimport/dllexport decorations.
+The standard auto-import feature described above is unable to resolve these
+references.
+
+The @samp{--enable-runtime-pseudo-relocs} switch allows these references to
+be resolved without error, while leaving the task of adjusting the references
+themselves (with their non-zero addends) to specialized code provided by the
+runtime environment. Recent versions of the cygwin and mingw environments and
+compilers provide this runtime support; older versions do not. However, the
+support is only necessary on the developer's platform; the compiled result will
+run without error on an older system.
+
+@samp{--enable-runtime-pseudo-relocs} is not the default; it must be explicitly
+enabled as needed.
+
+@cindex direct linking to a dll
+@item direct linking to a dll
+The cygwin/mingw ports of @command{ld} support the direct linking,
+including data symbols, to a dll without the usage of any import
+libraries. This is much faster and uses much less memory than does the
+traditional import library method, expecially when linking large
+libraries or applications. When @command{ld} creates an import lib, each
+function or variable exported from the dll is stored in its own bfd, even
+though a single bfd could contain many exports. The overhead involved in
+storing, loading, and processing so many bfd's is quite large, and explains the
+tremendous time, memory, and storage needed to link against particularly
+large or complex libraries when using import libs.
+
+Linking directly to a dll uses no extra command-line switches other than
+@samp{-L} and @samp{-l}, because @command{ld} already searches for a number
+of names to match each library. All that is needed from the developer's
+perspective is an understanding of this search, in order to force ld to
+select the dll instead of an import library.
+
+
+For instance, when ld is called with the argument @samp{-lxxx} it will attempt
+to find, in the first directory of its search path,
+
+@example
+libxxx.dll.a
+xxx.dll.a
+libxxx.a
+cygxxx.dll (*)
+libxxx.dll
+xxx.dll
+@end example
+
+before moving on to the next directory in the search path.
+
+(*) Actually, this is not @samp{cygxxx.dll} but in fact is @samp{<prefix>xxx.dll},
+where @samp{<prefix>} is set by the @command{ld} option
+@samp{--dll-search-prefix=<prefix>}. In the case of cygwin, the standard gcc spec
+file includes @samp{--dll-search-prefix=cyg}, so in effect we actually search for
+@samp{cygxxx.dll}.
+
+Other win32-based unix environments, such as mingw or pw32, may use other
+@samp{<prefix>}es, although at present only cygwin makes use of this feature. It
+was originally intended to help avoid name conflicts among dll's built for the
+various win32/un*x environments, so that (for example) two versions of a zlib dll
+could coexist on the same machine.
+
+The generic cygwin/mingw path layout uses a @samp{bin} directory for
+applications and dll's and a @samp{lib} directory for the import
+libraries (using cygwin nomenclature):
+
+@example
+bin/
+ cygxxx.dll
+lib/
+ libxxx.dll.a (in case of dll's)
+ libxxx.a (in case of static archive)
+@end example
+
+Linking directly to a dll without using the import library can be
+done two ways:
+
+1. Use the dll directly by adding the @samp{bin} path to the link line
+@example
+gcc -Wl,-verbose -o a.exe -L../bin/ -lxxx
+@end example
+
+However, as the dll's often have version numbers appended to their names
+(@samp{cygncurses-5.dll}) this will often fail, unless one specifies
+@samp{-L../bin -lncurses-5} to include the version. Import libs are generally
+not versioned, and do not have this difficulty.
+
+2. Create a symbolic link from the dll to a file in the @samp{lib}
+directory according to the above mentioned search pattern. This
+should be used to avoid unwanted changes in the tools needed for
+making the app/dll.
+
+@example
+ln -s bin/cygxxx.dll lib/[cyg|lib|]xxx.dll[.a]
+@end example
+
+Then you can link without any make environment changes.
+
+@example
+gcc -Wl,-verbose -o a.exe -L../lib/ -lxxx
+@end example
+
+This technique also avoids the version number problems, because the following is
+perfectly legal
+
+@example
+bin/
+ cygxxx-5.dll
+lib/
+ libxxx.dll.a -> ../bin/cygxxx-5.dll
+@end example
+
+Linking directly to a dll without using an import lib will work
+even when auto-import features are exercised, and even when
+@samp{--enable-runtime-pseudo-relocs} is used.
+
+Given the improvements in speed and memory usage, one might justifiably
+wonder why import libraries are used at all. There are two reasons:
+
+1. Until recently, the link-directly-to-dll functionality did @emph{not}
+work with auto-imported data.
+
+2. Sometimes it is necessary to include pure static objects within the
+import library (which otherwise contains only bfd's for indirection
+symbols that point to the exports of a dll). Again, the import lib
+for the cygwin kernel makes use of this ability, and it is not
+possible to do this without an import lib.
+
+So, import libs are not going away. But the ability to replace
+true import libs with a simple symbolic link to (or a copy of)
+a dll, in most cases, is a useful addition to the suite of tools
+binutils makes available to the win32 developer. Given the
+massive improvements in memory requirements during linking, storage
+requirements, and linking speed, we expect that many developers
+will soon begin to use this feature whenever possible.
+
+@item symbol aliasing
+@table @emph
+@item adding additional names
+Sometimes, it is useful to export symbols with additional names.
+A symbol @samp{foo} will be exported as @samp{foo}, but it can also be
+exported as @samp{_foo} by using special directives in the DEF file
+when creating the dll. This will affect also the optional created
+import library. Consider the following DEF file:
+
+@example
+LIBRARY "xyz.dll" BASE=0x61000000
+
+EXPORTS
+foo
+_foo = foo
+@end example
+
+The line @samp{_foo = foo} maps the symbol @samp{foo} to @samp{_foo}.
+
+Another method for creating a symbol alias is to create it in the
+source code using the "weak" attribute:
+
+@example
+void foo () @{ /* Do something. */; @}
+void _foo () __attribute__ ((weak, alias ("foo")));
+@end example
+
+See the gcc manual for more information about attributes and weak
+symbols.
+
+@item renaming symbols
+Sometimes it is useful to rename exports. For instance, the cygwin
+kernel does this regularly. A symbol @samp{_foo} can be exported as
+@samp{foo} but not as @samp{_foo} by using special directives in the
+DEF file. (This will also affect the import library, if it is
+created). In the following example:
+
+@example
+LIBRARY "xyz.dll" BASE=0x61000000
+
+EXPORTS
+_foo = foo
+@end example
+
+The line @samp{_foo = foo} maps the exported symbol @samp{foo} to
+@samp{_foo}.
+@end table
+
+Note: using a DEF file disables the default auto-export behavior,
+unless the @samp{--export-all-symbols} command line option is used.
+If, however, you are trying to rename symbols, then you should list
+@emph{all} desired exports in the DEF file, including the symbols
+that are not being renamed, and do @emph{not} use the
+@samp{--export-all-symbols} option. If you list only the
+renamed symbols in the DEF file, and use @samp{--export-all-symbols}
+to handle the other symbols, then the both the new names @emph{and}
+the original names for the the renamed symbols will be exported.
+In effect, you'd be aliasing those symbols, not renaming them,
+which is probably not what you wanted.
+@end table
+
+@ifclear GENERIC
+@lowersections
+@end ifclear
+@end ifset
+
@ifclear GENERIC
@ifset Hitachi
@c This stuff is pointless to say unless you're especially concerned
@c with Hitachi chips; don't enable it for generic case, please.
@node Hitachi
-@chapter @code{ld} and other Hitachi chips
+@chapter @command{ld} and other Hitachi chips
-@code{ld} also supports the H8/300H, the H8/500, and the Hitachi SH. No
+@command{ld} also supports the H8/300H, the H8/500, and the Hitachi SH. No
special features, commands, or command-line options are required for
these chips.
@end ifset
@end ifclear
@node i960
-@section @code{ld} and the Intel 960 family
+@section @command{ld} and the Intel 960 family
@cindex i960 support
libraries specific to each particular architecture, by including in the
search loop names suffixed with the string identifying the architecture.
-For example, if your @code{ld} command line included @w{@samp{-ACA}} as
+For example, if your @command{ld} command line included @w{@samp{-ACA}} as
well as @w{@samp{-ltry}}, the linker would look (in its built-in search
paths, and in any paths you specify with @samp{-L}) for a library with
the names
use will add another pair of name variants to search for when @w{@samp{-l}}
specifies a library.
-@cindex @code{--relax} on i960
+@cindex @option{--relax} on i960
@cindex relaxing on i960
-@code{ld} supports the @samp{--relax} option for the i960 family. If
-you specify @samp{--relax}, @code{ld} finds all @code{balx} and
+@command{ld} supports the @samp{--relax} option for the i960 family. If
+you specify @samp{--relax}, @command{ld} finds all @code{balx} and
@code{calx} instructions whose targets are within 24 bits, and turns
them into 24-bit program-counter relative @code{bal} and @code{cal}
-instructions, respectively. @code{ld} also turns @code{cal}
+instructions, respectively. @command{ld} also turns @code{cal}
instructions into @code{bal} instructions when it determines that the
target subroutine is a leaf routine (that is, the target subroutine does
not itself call any subroutines).
@end ifclear
@node ARM
-@section @code{ld}'s support for interworking between ARM and Thumb code
+@section @command{ld}'s support for interworking between ARM and Thumb code
@cindex ARM interworking support
@kindex --support-old-code
-For the ARM, @code{ld} will generate code stubs to allow functions calls
+For the ARM, @command{ld} will generate code stubs to allow functions calls
betweem ARM and Thumb code. These stubs only work with code that has
been compiled and assembled with the @samp{-mthumb-interwork} command
line option. If it is necessary to link with old ARM object files or
executing in Thumb mode straight away.
@node HPPA ELF32
-@section @code{ld} and HPPA 32-bit ELF support
+@section @command{ld} and HPPA 32-bit ELF support
@cindex HPPA multiple sub-space stubs
@kindex --multi-subspace
-When generating a shared library, @code{ld} will by default generate
+When generating a shared library, @command{ld} will by default generate
import stubs suitable for use with a single sub-space application.
-The @samp{--multi-subspace} switch causes @code{ld} to generate export
+The @samp{--multi-subspace} switch causes @command{ld} to generate export
stubs, and different (larger) import stubs suitable for use with
multiple sub-spaces.
@cindex HPPA stub grouping
@kindex --stub-group-size=@var{N}
-Long branch stubs and import/export stubs are placed by @code{ld} in
+Long branch stubs and import/export stubs are placed by @command{ld} in
stub sections located between groups of input sections.
@samp{--stub-group-size} specifies the maximum size of a group of input
sections handled by one stub section. Since branch offsets are signed,
A negative value for @samp{N} chooses this scheme, ensuring that
branches to stubs always use a negative offset. Two special values of
@samp{N} are recognized, @samp{1} and @samp{-1}. These both instruct
-@code{ld} to automatically size input section groups for the branch types
+@command{ld} to automatically size input section groups for the branch types
detected, with the same behaviour regarding stub placement as other
positive or negative values of @samp{N} respectively.
create a larger group (of one section). If input sections are too
large, it may not be possible for a branch to reach its stub.
+@ifset MMIX
+@node MMIX
+@section @code{ld} and MMIX
+For MMIX, there is choice of generating @code{ELF} object files or
+@code{mmo} object files when linking. The simulator @code{mmix}
+understands the @code{mmo} format. The binutils @code{objcopy} utility
+can translate between the two formats.
+
+There is one special section, the @samp{.MMIX.reg_contents} section.
+Contents in this section is assumed to correspond to that of global
+registers, and symbols referring to it are translated to special symbols,
+equal to registers. In a final link, the start address of the
+@samp{.MMIX.reg_contents} section corresponds to the first allocated
+global register multiplied by 8. Register @code{$255} is not included in
+this section; it is always set to the program entry, which is at the
+symbol @code{Main} for @code{mmo} files.
+
+Symbols with the prefix @code{__.MMIX.start.}, for example
+@code{__.MMIX.start..text} and @code{__.MMIX.start..data} are special;
+there must be only one each, even if they are local. The default linker
+script uses these to set the default start address of a section.
+
+Initial and trailing multiples of zero-valued 32-bit words in a section,
+are left out from an mmo file.
+@end ifset
+
+@ifset MSP430
+@node MSP430
+@section @code{ld} and MSP430
+For the MSP430 it is possible to select the MPU architecture. The flag @samp{-m [mpu type]}
+will select an appropriate linker script for selected MPU type. (To get a list of known MPUs
+just pass @samp{-m help} option to the linker).
+
+@cindex MSP430 extra sections
+The linker will recognize some extra sections which are MSP430 specific:
+
+@table @code
+@item @samp{.vectors}
+Defines a portion of ROM where interrupt vectors located.
+
+@item @samp{.bootloader}
+Defines the bootloader portion of the ROM (if applicable). Any code
+in this section will be uploaded to the MPU.
+
+@item @samp{.infomem}
+Defines an information memory section (if applicable). Any code in
+this section will be uploaded to the MPU.
+
+@item @samp{.infomemnobits}
+This is the same as the @samp{.infomem} section except that any code
+in this section will not be uploaded to the MPU.
+
+@item @samp{.noinit}
+Denotes a portion of RAM located above @samp{.bss} section.
+
+The last two sections are used by gcc.
+@end table
+@end ifset
+
@ifset TICOFF
@node TI COFF
-@section @code{ld}'s support for various TI COFF versions
+@section @command{ld}'s support for various TI COFF versions
@cindex TI COFF versions
@kindex --format=@var{version}
The @samp{--format} switch allows selection of one of the various
TI COFF versions. The latest of this writing is 2; versions 0 and 1 are
also supported. The TI COFF versions also vary in header byte-order
-format; @code{ld} will read any version or byte order, but the output
+format; @command{ld} will read any version or byte order, but the output
header format depends on the default specified by the specific target.
@end ifset
@node Reporting Bugs
@chapter Reporting Bugs
-@cindex bugs in @code{ld}
-@cindex reporting bugs in @code{ld}
+@cindex bugs in @command{ld}
+@cindex reporting bugs in @command{ld}
-Your bug reports play an essential role in making @code{ld} reliable.
+Your bug reports play an essential role in making @command{ld} reliable.
Reporting a bug may help you by bringing a solution to your problem, or
it may not. But in any case the principal function of a bug report is
-to help the entire community by making the next version of @code{ld}
+to help the entire community by making the next version of @command{ld}
work better. Bug reports are your contribution to the maintenance of
-@code{ld}.
+@command{ld}.
In order for a bug report to serve its purpose, you must include the
information that enables us to fix the bug.
@cindex crash of linker
@item
If the linker gets a fatal signal, for any input whatever, that is a
-@code{ld} bug. Reliable linkers never crash.
+@command{ld} bug. Reliable linkers never crash.
@cindex error on valid input
@item
-If @code{ld} produces an error message for valid input, that is a bug.
+If @command{ld} produces an error message for valid input, that is a bug.
@cindex invalid input
@item
-If @code{ld} does not produce an error message for invalid input, that
+If @command{ld} does not produce an error message for invalid input, that
may be a bug. In the general case, the linker can not verify that
object files are correct.
@item
If you are an experienced user of linkers, your suggestions for
-improvement of @code{ld} are welcome in any case.
+improvement of @command{ld} are welcome in any case.
@end itemize
@node Bug Reporting
@section How to report bugs
@cindex bug reports
-@cindex @code{ld} bugs, reporting
+@cindex @command{ld} bugs, reporting
A number of companies and individuals offer support for @sc{gnu}
-products. If you obtained @code{ld} from a support organization, we
+products. If you obtained @command{ld} from a support organization, we
recommend you contact that organization first.
You can find contact information for many support companies and
individuals in the file @file{etc/SERVICE} in the @sc{gnu} Emacs
distribution.
-Otherwise, send bug reports for @code{ld} to
+Otherwise, send bug reports for @command{ld} to
@samp{bug-binutils@@gnu.org}.
The fundamental principle of reporting bugs usefully is this:
Often people omit facts because they think they know what causes the
problem and assume that some details do not matter. Thus, you might
-assume that the name of a symbol you use in an example does not matter.
-Well, probably it does not, but one cannot be sure. Perhaps the bug is
-a stray memory reference which happens to fetch from the location where
-that name is stored in memory; perhaps, if the name were different, the
-contents of that location would fool the linker into doing the right
-thing despite the bug. Play it safe and give a specific, complete
-example. That is the easiest thing for you to do, and the most helpful.
-
-Keep in mind that the purpose of a bug report is to enable us to fix the bug if
-it is new to us. Therefore, always write your bug reports on the assumption
-that the bug has not been reported previously.
+assume that the name of a symbol you use in an example does not
+matter. Well, probably it does not, but one cannot be sure. Perhaps
+the bug is a stray memory reference which happens to fetch from the
+location where that name is stored in memory; perhaps, if the name
+were different, the contents of that location would fool the linker
+into doing the right thing despite the bug. Play it safe and give a
+specific, complete example. That is the easiest thing for you to do,
+and the most helpful.
+
+Keep in mind that the purpose of a bug report is to enable us to fix
+the bug if it is new to us. Therefore, always write your bug reports
+on the assumption that the bug has not been reported previously.
Sometimes people give a few sketchy facts and ask, ``Does this ring a
bell?'' Those bug reports are useless, and we urge everyone to
@itemize @bullet
@item
-The version of @code{ld}. @code{ld} announces it if you start it with
+The version of @command{ld}. @command{ld} announces it if you start it with
the @samp{--version} argument.
Without this, we will not know whether there is any point in looking for
-the bug in the current version of @code{ld}.
+the bug in the current version of @command{ld}.
@item
-Any patches you may have applied to the @code{ld} source, including any
+Any patches you may have applied to the @command{ld} source, including any
patches made to the @code{BFD} library.
@item
version number.
@item
-What compiler (and its version) was used to compile @code{ld}---e.g.
+What compiler (and its version) was used to compile @command{ld}---e.g.
``@code{gcc-2.7}''.
@item
@item
A complete input file, or set of input files, that will reproduce the
-bug. It is generally most helpful to send the actual object files,
-uuencoded if necessary to get them through the mail system. Making them
-available for anonymous FTP is not as good, but may be the only
-reasonable choice for large object files.
+bug. It is generally most helpful to send the actual object files
+provided that they are reasonably small. Say no more than 10K. For
+bigger files you can either make them available by FTP or HTTP or else
+state that you are willing to send the object file(s) to whomever
+requests them. (Note - your email will be going to a mailing list, so
+we do not want to clog it up with large attachments). But small
+attachments are best.
If the source files were assembled using @code{gas} or compiled using
@code{gcc}, then it may be OK to send the source files rather than the
A description of what behavior you observe that you believe is
incorrect. For example, ``It gets a fatal signal.''
-Of course, if the bug is that @code{ld} gets a fatal signal, then we
+Of course, if the bug is that @command{ld} gets a fatal signal, then we
will certainly notice it. But if the bug is incorrect output, we might
not notice unless it is glaringly wrong. You might as well not give us
a chance to make a mistake.
Even if the problem you experience is a fatal signal, you should still
say so explicitly. Suppose something strange is going on, such as, your
-copy of @code{ld} is out of synch, or you have encountered a bug in the
+copy of @command{ld} is out of synch, or you have encountered a bug in the
C library on your system. (This has happened!) Your copy might crash
and ours would not. If you told us to expect a crash, then when ours
fails to crash, we would know that the bug was not happening for us. If
any conclusion from our observations.
@item
-If you wish to suggest changes to the @code{ld} source, send us context
+If you wish to suggest changes to the @command{ld} source, send us context
diffs, as generated by @code{diff} with the @samp{-u}, @samp{-c}, or
@samp{-p} option. Always send diffs from the old file to the new file.
-If you even discuss something in the @code{ld} source, refer to it by
+If you even discuss something in the @command{ld} source, refer to it by
context, not by line number.
The line numbers in our development sources will not match those in your
a patch is all we need. We might see problems with your patch and decide
to fix the problem another way, or we might not understand it at all.
-Sometimes with a program as complicated as @code{ld} it is very hard to
+Sometimes with a program as complicated as @command{ld} it is very hard to
construct an example that will make the program follow a certain path
through the code. If you do not send us the example, we will not be
able to construct one, so we will not be able to verify that the bug is
@node MRI
@appendix MRI Compatible Script Files
@cindex MRI compatibility
-To aid users making the transition to @sc{gnu} @code{ld} from the MRI
-linker, @code{ld} can use MRI compatible linker scripts as an
+To aid users making the transition to @sc{gnu} @command{ld} from the MRI
+linker, @command{ld} can use MRI compatible linker scripts as an
alternative to the more general-purpose linker scripting language
described in @ref{Scripts}. MRI compatible linker scripts have a much
simpler command set than the scripting language otherwise used with
-@code{ld}. @sc{gnu} @code{ld} supports the most commonly used MRI
+@command{ld}. @sc{gnu} @command{ld} supports the most commonly used MRI
linker commands; these commands are described here.
In general, MRI scripts aren't of much use with the @code{a.out} object
Each command in an MRI-compatible script occupies its own line; each
command line starts with the keyword that identifies the command (though
blank lines are also allowed for punctuation). If a line of an
-MRI-compatible script begins with an unrecognized keyword, @code{ld}
+MRI-compatible script begins with an unrecognized keyword, @command{ld}
issues a warning message, but continues processing the script.
Lines beginning with @samp{*} are comments.
@cindex @code{ABSOLUTE} (MRI)
@item ABSOLUTE @var{secname}
@itemx ABSOLUTE @var{secname}, @var{secname}, @dots{} @var{secname}
-Normally, @code{ld} includes in the output file all sections from all
+Normally, @command{ld} includes in the output file all sections from all
the input files. However, in an MRI-compatible script, you can use the
@code{ABSOLUTE} command to restrict the sections that will be present in
your output program. If the @code{ABSOLUTE} command is used at all in a
@cindex @code{LIST} (MRI)
@item LIST @var{anything}@dots{}
Print (to the standard output file) a link map, as produced by the
-@code{ld} command-line option @samp{-M}.
+@command{ld} command-line option @samp{-M}.
The keyword @code{LIST} may be followed by anything on the
same line, with no change in its effect.
@item LOAD @var{filename}
@itemx LOAD @var{filename}, @var{filename}, @dots{} @var{filename}
Include one or more object file @var{filename} in the link; this has the
-same effect as specifying @var{filename} directly on the @code{ld}
+same effect as specifying @var{filename} directly on the @command{ld}
command line.
@cindex @code{NAME} (MRI)
@item NAME @var{output-name}
-@var{output-name} is the name for the program produced by @code{ld}; the
+@var{output-name} is the name for the program produced by @command{ld}; the
MRI-compatible command @code{NAME} is equivalent to the command-line
option @samp{-o} or the general script language command @code{OUTPUT}.
@cindex @code{ORDER} (MRI)
@item ORDER @var{secname}, @var{secname}, @dots{} @var{secname}
@itemx ORDER @var{secname} @var{secname} @var{secname}
-Normally, @code{ld} orders the sections in its output file in the
+Normally, @command{ld} orders the sections in its output file in the
order in which they first appear in the input files. In an MRI-compatible
script, you can override this ordering with the @code{ORDER} command. The
sections you list with @code{ORDER} will appear first in your output
projects / thirdparty / binutils-gdb.git / blobdiff