\input texinfo
@setfilename ld.info
+@c Copyright 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000,
+@c 2001 Free Software Foundation, Inc.
@syncodeindex ky cp
@include configdoc.texi
@c (configdoc.texi is generated by the Makefile)
@ifinfo
This file documents the @sc{gnu} linker LD version @value{VERSION}.
-Copyright (C) 1991, 92, 93, 94, 95, 96, 97, 98, 1999 Free Software Foundation, Inc.
+Copyright (C) 1991, 92, 93, 94, 95, 96, 97, 98, 99, 2000 Free Software Foundation, Inc.
-Permission is granted to make and distribute verbatim copies of
-this manual provided the copyright notice and this permission notice
-are preserved on all copies.
-
-Permission is granted to copy and distribute modified versions of this
-manual under the conditions for verbatim copying, provided also that
-the entire resulting derived work is distributed under the terms of a
-permission notice identical to this one.
+@ignore
-Permission is granted to copy and distribute translations of this manual
-into another language, under the above conditions for modified versions.
+Permission is granted to copy, distribute and/or modify this document
+under the terms of the GNU Free Documentation License, Version 1.1
+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".
-@ignore
Permission is granted to process this file through Tex and print the
results, provided the printed document carries copying permission
notice identical to this one except for the removal of this paragraph
@subtitle Version @value{VERSION}
@author Steve Chamberlain
@author Ian Lance Taylor
-@author Cygnus Solutions
@page
@tex
{\parskip=0pt
-\hfill Cygnus Solutions\par
-\hfill ian\@cygnus.com, doc\@cygnus.com\par
+\hfill Red Hat Inc\par
+\hfill nickc\@credhat.com, doc\@redhat.com\par
\hfill {\it Using LD, the GNU linker}\par
\hfill Edited by Jeffrey Osier (jeffrey\@cygnus.com)\par
}
@end tex
@vskip 0pt plus 1filll
-Copyright @copyright{} 1991, 92, 93, 94, 95, 96, 97, 98, 1999 Free Software Foundation, Inc.
+Copyright @copyright{} 1991, 92, 93, 94, 95, 96, 97, 98, 99, 2000 Free Software Foundation, Inc.
-Permission is granted to make and distribute verbatim copies of
-this manual provided the copyright notice and this permission notice
-are preserved on all copies.
+ Permission is granted to copy, distribute and/or modify this document
+ under the terms of the GNU Free Documentation License, Version 1.1
+ 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".
-Permission is granted to copy and distribute modified versions of this
-manual under the conditions for verbatim copying, provided also that
-the entire resulting derived work is distributed under the terms of a
-permission notice identical to this one.
-
-Permission is granted to copy and distribute translations of this manual
-into another language, under the above conditions for modified versions.
@end titlepage
@end iftex
@c FIXME: Talk about importance of *order* of args, cmds to linker!
@top Using ld
This file documents the @sc{gnu} linker ld version @value{VERSION}.
+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
* Overview:: Overview
* Invocation:: Invocation
@ifset I960
* i960:: ld and the Intel 960 family
@end ifset
+@ifset TICOFF
+* TI COFF:: ld and the TI COFF
+@end ifset
@end ifclear
@ifclear SingleFormat
* BFD:: BFD
* Reporting Bugs:: Reporting Bugs
* MRI:: MRI Compatible Script Files
+* GNU Free Documentation License:: GNU Free Documentation License
* Index:: Index
@end menu
@end ifinfo
option that requires them.
For options whose names are multiple letters, either one dash or two can
-precede the option name; for example, @samp{--oformat} and
-@samp{--oformat} are equivalent. Arguments to multiple-letter options
-must either be separated from the option name by an equals sign, or be
-given as separate arguments immediately following the option that
-requires them. For example, @samp{--oformat srec} and
-@samp{--oformat=srec} are equivalent. Unique abbreviations of the names
-of multiple-letter options are accepted.
+precede the option name; for example, @samp{-trace-symbol} and
+@samp{--trace-symbol} are equivalent. Note - there is one exception to
+this rule. Multiple letter options that start with a lower case 'o' can
+only be preceeded by two dashes. This is to reduce confusion with the
+@samp{-o} option. So for example @samp{-omagic} sets the output file
+name to @samp{magic} whereas @samp{--omagic} sets the NMAGIC flag on the
+output.
+
+Arguments to multiple-letter options must either be separated from the
+option name by an equals sign, or be given as separate arguments
+immediately following the option that requires them. For example,
+@samp{--trace-symbol foo} and @samp{--trace-symbol=foo} are equivalent.
+Unique abbreviations of the names of multiple-letter options are
+accepted.
+
+Note - if the linker is being invoked indirectly, via a compiler driver
+(eg @samp{gcc}) then all the linker command line options should be
+prefixed by @samp{-Wl,} (or whatever is appropriate for the particular
+compiler driver) like this:
+
+@smallexample
+ gcc -Wl,--startgroup foo.o bar.o -Wl,--endgroup
+@end smallexample
+
+This is important, because otherwise the compiler driver program may
+silently drop the linker options, resulting in a bad link.
+
+Here is a table of the generic command line switches accepted by the GNU
+linker:
@table @code
@kindex -a@var{keyword}
binary format. You can also use @samp{-b} to switch formats explicitly (when
linking object files of different formats), by including
@samp{-b @var{input-format}} before each group of object files in a
-particular format.
+particular format.
The default format is taken from the environment variable
@code{GNUTARGET}.
@kindex -d
@kindex -dc
@kindex -dp
-@item -d
+@item -d
@itemx -dc
@itemx -dp
These three options are equivalent; multiple forms are supported for
@cindex entry point, from command line
@kindex -e @var{entry}
@kindex --entry=@var{entry}
-@item -e @var{entry}
+@item -e @var{entry}
@itemx --entry=@var{entry}
Use @var{entry} as the explicit symbol for beginning execution of your
program, rather than the default entry point. If there is no symbol
environment variable. The @sc{gnu} linker will ignore the @code{-F}
option when not creating an ELF shared object.
+@cindex finalization function
+@kindex -fini
+@item -fini @var{name}
+When creating an ELF executable or shared object, call NAME when the
+executable or shared object is unloaded, by setting DT_FINI to the
+address of the function. By default, the linker uses @code{_fini} as
+the function to call.
+
@kindex -g
@item -g
Ignored. Provided for compatibility with other tools.
@item -i
Perform an incremental link (same as option @samp{-r}).
+@cindex initialization function
+@kindex -init
+@item -init @var{name}
+When creating an ELF executable or shared object, call NAME when the
+executable or shared object is loaded, by setting DT_INIT to the address
+of the function. By default, the linker uses @code{_init} as the
+function to call.
+
@cindex archive files, from cmd line
@kindex -l@var{archive}
@kindex --library=@var{archive}
@cindex search directory, from cmd line
@kindex -L@var{dir}
@kindex --library-path=@var{dir}
-@item -L@var{searchdir}
+@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
@kindex --nmagic
@item -n
@itemx --nmagic
-Set the text segment to be read only, and mark the output as
+Turn off page alignment of sections, and mark the output as
@code{NMAGIC} if possible.
@kindex -N
@kindex --omagic
@cindex read/write from cmd line
@cindex OMAGIC
-@item -N
+@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
the output. This might take significantly longer and therefore probably
should only be enabled for the final binary.
+@kindex -q
+@kindex --emit-relocs
+@cindex retain relocations in final executable
+@item -q
+@itemx --emit-relocs
+Leave relocation sections and contents in fully linked exececutables.
+Post link analysis and optimization tools may need this information in
+order to perform correct modifications of executables. This results
+in larger executables.
+
@cindex partial link
@cindex relocatable output
@kindex -r
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 @code{-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}.
@kindex -s
@kindex --strip-all
@cindex strip all symbols
-@item -s
+@item -s
@itemx --strip-all
Omit all symbol information from the output file.
@kindex -S
@kindex --strip-debug
@cindex strip debugger symbols
-@item -S
+@item -S
@itemx --strip-debug
Omit debugger symbol information (but not all symbols) from the output file.
@kindex -t
@kindex --trace
@cindex input files, displaying
-@item -t
+@item -t
@itemx --trace
Print the names of the input files as @code{ld} processes them.
@kindex -Ur
@cindex constructors
-@item -Ur
+@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}
be added to. Use @samp{-Ur} only for the last partial link, and
@samp{-r} for the others.
+@kindex --unique[=@var{SECTION}]
+@item --unique[=@var{SECTION}]
+Creates a separate output section for every input section matching
+@var{SECTION}, or if the optional wildcard @var{SECTION} argument is
+missing, for every orphan input section. An orphan section is one not
+specifically mentioned in a linker script. You may use this option
+multiple times on the command line; It prevents the normal merging of
+input sections with the same name, overriding output section assignments
+in a linker script.
+
@kindex -v
@kindex -V
@kindex --version
@kindex --discard-locals
@cindex local symbols, deleting
@cindex L, deleting symbols beginning
-@item -X
+@item -X
@itemx --discard-locals
Delete all temporary local symbols. For most targets, this is all local
symbols whose names begin with @samp{L}.
@kindex -z @var{keyword}
@item -z @var{keyword}
-This option is ignored for Solaris compatibility.
+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
+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
+before all symbols but the primary executable. @code{loadfltr} marks
+the object that its filtees be processed immediately at runtime.
+@code{nodefaultlib} marks the object that the search for dependencies
+of this object will ignore any default library search paths.
+@code{nodelete} marks the object shouldn't be unloaded at runtime.
+@code{nodlopen} marks the object not available to @code{dlopen}.
+@code{nodump} marks the object can not be dumped by @code{dldump}.
+@code{now} marks the object with the non-lazy runtime binding.
+@code{origin} marks the object may contain $ORIGIN.
+@code{defs} disallows undefined symbols.
@kindex -(
@cindex groups of archives
multiple times on the command line: it affects library searching for
@code{-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
+platforms which support shared libraries.
+
@kindex -Bstatic
@kindex -dn
@kindex -non_shared
@kindex -static
-@item -Bstatic
+@item -Bstatic
@itemx -dn
@itemx -non_shared
@itemx -static
@kindex --check-sections
@kindex --no-check-sections
@item --check-sections
-@item --no-check-sections
+@itemx --no-check-sections
Asks the linker @emph{not} to check section addresses after they have
been assigned to see if there any overlaps. Normally the linker will
perform this check, and if it finds any overlaps it will produce
@var{expression}.
@cindex demangling, from command line
-@kindex --demangle
+@kindex --demangle[=@var{style}]
@kindex --no-demangle
-@item --demangle
+@item --demangle[=@var{style}]
@itemx --no-demangle
These options control whether to demangle symbol names in error messages
and other output. When the linker is told to demangle, it tries to
present symbol names in a readable fashion: it strips leading
underscores if they are used by the object file format, and converts C++
-mangled symbol names into user readable names. The linker will demangle
-by default unless the environment variable @samp{COLLECT_NO_DEMANGLE} is
-set. These options may be used to override the default.
+mangled symbol names into user readable names. Different compilers have
+different mangling styles. The optional demangling style argument can be used
+to choose an appropriate demangling style for your compiler. The linker will
+demangle by default unless the environment variable @samp{COLLECT_NO_DEMANGLE}
+is set. These options may be used to override the default.
@cindex dynamic linker, from command line
@kindex --dynamic-linker @var{file}
@item --help
Print a summary of the command-line options on the standard output and exit.
+@kindex --target-help
+@item --target-help
+Print a summary of all target specific options on the standard output and exit.
+
@kindex -Map
@item -Map @var{mapfile}
Print a link map to the file @var{mapfile}. See the description of the
while linking a large executable.
@kindex --no-undefined
+@kindex -z defs
@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. This option
+are allowed and left to be resolved by the runtime loader. These options
disallows such undefined symbols.
+@kindex --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.
+
@kindex --no-warn-mismatch
@item --no-warn-mismatch
Normally @code{ld} will give an error if you try to link together input
@cindex synthesizing linker
@cindex relaxing addressing modes
@item --relax
-An option with machine dependent effects.
+An option with machine dependent effects.
@ifset GENERIC
This option is only supported on a few targets.
@end ifset
either by specifying a list of names separated by colons, or by
appearing multiple times.
+This option should be used with caution as it overrides the search path
+that may have been hard compiled into a shared library. In such a case it
+is possible to use unintentionally a different search path than the
+runtime linker would do.
+
The linker uses the following search paths to locate required shared
libraries.
@enumerate
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
-at link time.
+at link time. It is for the native linker only.
@item
On an ELF system, if the @code{-rpath} and @code{rpath-link} options
were not used, search the contents of the environment variable
-@code{LD_RUN_PATH}.
+@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.
For a native linker, the contents of the environment variable
@code{LD_LIBRARY_PATH}.
@item
+For a native ELF linker, the directories in @code{DT_RUNPATH} or
+@code{DT_RPATH} of a shared library are searched for shared
+libraries needed by it. The @code{DT_RPATH} entries are ignored if
+@code{DT_RUNPATH} entries exist.
+@item
The default directories, normally @file{/lib} and @file{/usr/lib}.
@item
For a native linker on an ELF system, if the file @file{/etc/ld.so.conf}
alignment constraints.
@kindex --split-by-file
-@item --split-by-file
+@item --split-by-file [@var{size}]
Similar to @code{--split-by-reloc} but creates a new output section for
-each input file.
+each input file when @var{size} is reached. @var{size} defaults to a
+size of 1 if not given.
@kindex --split-by-reloc
-@item --split-by-reloc @var{count}
-Trys to creates extra sections in the output file so that no single
+@item --split-by-reloc [@var{count}]
+Tries to creates extra sections in the output file so that no single
output section in the file contains more than @var{count} relocations.
-This is useful when generating huge relocatable for downloading into
+This is useful when generating huge relocatable files for downloading into
certain real time kernels with the COFF object file format; since COFF
cannot represent more than 65535 relocations in a single section. Note
that this will fail to work with object file formats which do not
support arbitrary sections. The linker will not split up individual
input sections for redistribution, so if a single input section contains
more than @var{count} relocations one output section will contain that
-many relocations.
+many relocations. @var{count} defaults to a value of 32768.
@kindex --stats
@item --stats
trouble). The @samp{--traditional-format} switch tells @code{ld} to not
combine duplicate entries.
+@kindex --section-start @var{sectionname}=@var{org}
+@item --section-start @var{sectionname}=@var{org}
+Locate a section in the output file at the absolute
+address given by @var{org}. You may use this option as many
+times as necessary to locate multiple sections in the command
+line.
+@var{org} must be a single hexadecimal integer;
+for compatibility with other linkers, you may omit the leading
+@samp{0x} usually associated with hexadecimal values. @emph{Note:} there
+should be no white space between @var{sectionname}, the equals
+sign (``@key{=}''), and @var{org}.
+
@kindex -Tbss @var{org}
@kindex -Tdata @var{org}
@kindex -Ttext @var{org}
@kindex --verbose
@cindex verbose
@item --dll-verbose
-@item --verbose
+@itemx --verbose
Display the version number for @code{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.
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
+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.
+
@kindex --wrap
@item --wrap @var{symbol}
Use a wrapper function for @var{symbol}. Any undefined reference to
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}.
+@kindex --enable-new-dtags
+@kindex --disable-new-dtags
+@item --enable-new-dtags
+@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
+created. By default, the new dynamic tags are not created. Note that
+those options are only available for ELF systems.
+
@end table
@subsection Options specific to i386 PE targets
exported.
@kindex --exclude-symbols
-@item --exclude-symbols @var{symbol,symbol,...}
+@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.
followed by a series of symbol assignments and output section
descriptions enclosed in curly braces.
-The first line in the above example sets the special symbol @samp{.},
-which is the location counter. If you do not specify the address of an
-output section in some other way (other ways are described later), the
-address is set from the current value of the location counter. The
-location counter is then incremented by the size of the output section.
-
The first line inside the @samp{SECTIONS} command of the above example
sets the value of the special symbol @samp{.}, which is the location
counter. If you do not specify the address of an output section in some
entry point by trying each of the following methods in order, and
stopping when one of them succeeds:
@itemize @bullet
-@item
+@item
the @samp{-e} @var{entry} command-line option;
-@item
+@item
the @code{ENTRY(@var{symbol})} command in a linker script;
-@item
+@item
the value of the symbol @code{start}, if defined;
-@item
+@item
the address of the first byte of the @samp{.text} section, if present;
-@item
+@item
The address @code{0}.
@end itemize
@subsection Output section description
The full description of an output section looks like this:
@smallexample
-@group
+@group
@var{section} [@var{address}] [(@var{type})] : [AT(@var{lma})]
@{
@var{output-section-command}
@var{output-section-command}
@dots{}
- @} [>@var{region}] [:@var{phdr} :@var{phdr} @dots{}] [=@var{fillexp}]
+ @} [>@var{region}] [AT>@var{lma_region}] [:@var{phdr} :@var{phdr} @dots{}] [=@var{fillexp}]
@end group
@end smallexample
*(.text)
@end smallexample
@noindent
-Here the @samp{*} is a wildcard which matches any file name. To exclude a file
-from matching the file name wildcard, EXCLUDE_FILE may be used to match all files
-except the one specified by EXCLUDE_FILE. For example:
+Here the @samp{*} is a wildcard which matches any file name. To exclude a list
+of files from matching the file name wildcard, EXCLUDE_FILE may be used to
+match all files except the ones specified in the EXCLUDE_FILE list. For
+example:
@smallexample
-(*(EXCLUDE_FILE (*crtend.o) .ctors))
+(*(EXCLUDE_FILE (*crtend.o *otherfile.o) .ctors))
@end smallexample
-will cause all .ctors sections from all files except crtend.o to be included.
+will cause all .ctors sections from all files except @file{crtend.o} and
+@file{otherfile.o} to be included.
There are two ways to include more than one section:
@smallexample
@cindex KEEP
@cindex garbage collection
When link-time garbage collection is in use (@samp{--gc-sections}),
-it is often useful to mark sections that should not be eliminated.
+it is often useful to mark sections that should not be eliminated.
This is accomplished by surrounding an input section's wildcard entry
with @code{KEEP()}, as in @code{KEEP(*(.init))} or
@code{KEEP(SORT(*)(.ctors))}.
@}
@}
@end group
-@end smallexample
+@end smallexample
@node Output Section Data
@subsection Output section data
true of, for example, S-records, the value will be stored in the
endianness of the first input object file.
+Note - these commands only work inside a section description and not
+between them, so the following will produce an error from the linker:
+@smallexample
+SECTIONS @{@ .text : @{@ *(.text) @}@ LONG(1) .data : @{@ *(.data) @}@ @}@
+@end smallexample
+whereas this will work:
+@smallexample
+SECTIONS @{@ .text : @{@ *(.text) ; LONG(1) @}@ .data : @{@ *(.data) @}@ @}@
+@end smallexample
+
@kindex FILL(@var{expression})
@cindex holes, filling
@cindex unspecified memory
We showed above that the full description of an output section looked
like this:
@smallexample
-@group
+@group
@var{section} [@var{address}] [(@var{type})] : [AT(@var{lma})]
@{
@var{output-section-command}
@var{output-section-command}
@dots{}
- @} [>@var{region}] [:@var{phdr} :@var{phdr} @dots{}] [=@var{fillexp}]
+ @} [>@var{region}] [AT>@var{lma_region}] [:@var{phdr} :@var{phdr} @dots{}] [=@var{fillexp}]
@end group
@end smallexample
We've already described @var{section}, @var{address}, and
@var{output-section-command}. In this section we will describe the
remaining section attributes.
-@menu
+@menu
* Output Section Type:: Output section type
* Output Section LMA:: Output section LMA
* Output Section Region:: Output section region
@node Output Section LMA
@subsubsection Output section LMA
+@kindex AT>@var{lma_region}
@kindex AT(@var{lma})
@cindex load address
@cindex section load address
The linker will normally set the LMA equal to the VMA. You can change
that by using the @code{AT} keyword. The expression @var{lma} that
-follows the @code{AT} keyword specifies the load address of the section.
+follows the @code{AT} keyword specifies the load address of the
+section. Alternatively, with @samp{AT>@var{lma_region}} expression,
+you may specify a memory region for the section's load address. @xref{MEMORY}.
@cindex ROM initialized data
@cindex initialized data in ROM
SECTIONS
@{
.text 0x1000 : @{ *(.text) _etext = . ; @}
- .mdata 0x2000 :
+ .mdata 0x2000 :
AT ( ADDR (.text) + SIZEOF (.text) )
@{ _data = . ; *(.data); _edata = . ; @}
.bss 0x3000 :
you wish. The syntax is:
@smallexample
@group
-MEMORY
+MEMORY
@{
@var{name} [(@var{attr})] : ORIGIN = @var{origin}, LENGTH = @var{len}
@dots{}
@smallexample
@group
-MEMORY
+MEMORY
@{
rom (rx) : ORIGIN = 0, LENGTH = 256K
ram (!rx) : org = 0x40000000, l = 4M
global:
foo1;
local:
- old*;
- original*;
- new*;
+ old*;
+ original*;
+ new*;
@};
VERS_1.2 @{
@samp{.text} section from @file{file3}. The notation @samp{= 0x1234}
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
+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:
+
+@smallexample
+SECTIONS
+@{
+ . = 0x100
+ .text: @{
+ *(.text)
+ . = 0x200
+ @}
+ . = 0x500
+ .data: @{
+ *(.data)
+ . += 0x600
+ @}
+@}
+@end smallexample
+
+The @samp{.text} section will be assigned a starting address of 0x100
+and a size of exactly 0x200 bytes, even if there is not enough data in
+the @samp{.text} input sections to fill this area. (If there is too
+much data, an error will be produced because this would be an attempt to
+move @code{.} backwards). The @samp{.data} section will start at 0x500
+and it will have an extra 0x600 bytes worth of space after the end of
+the values from the @samp{.data} input sections and before the end of
+the @samp{.data} output section itself.
+
@need 2000
@node Operators
@subsection Operators
(lowest)
@end smallexample
Notes:
-(1) Prefix operators
+(1) Prefix operators
(2) @xref{Assignments}.
@c TEXI2ROFF-KILL
@end ifinfo
height2pt&\omit&&\omit&&\omit&\cr
&highest&&&&&\cr
% '176 is tilde, '~' in tt font
-&1&&left&&\qquad- \char'176\ !\qquad\dag&\cr
+&1&&left&&\qquad- \char'176\ !\qquad\dag&\cr
&2&&left&&* / \%&\cr
&3&&left&&+ -&\cr
&4&&left&&>> <<&\cr
@group
SECTIONS
@{
- .text 9+this_isnt_constant :
+ .text 9+this_isnt_constant :
@{ *(.text) @}
@}
@end group
@group
SECTIONS @{ @dots{}
.output1 :
- @{
+ @{
start_of_output_1 = ABSOLUTE(.);
@dots{}
@}
* H8/300:: @code{ld} and the H8/300
* 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 TICOFF
+* TI COFF:: @code{ld} and TI COFF
+@end ifset
@end menu
@end ifset
@section @code{ld}'s support for interworking between ARM and Thumb code
@cindex ARM interworking support
-@cindex --support-old-code
+@kindex --support-old-code
For the ARM, @code{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
the linker does not support generating stubs for function calls to
non-interworking aware Thumb code.
+@cindex thumb entry point
+@cindex entry point, thumb
+@kindex --thumb-entry=@var{entry}
+The @samp{--thumb-entry} switch is a duplicate of the generic
+@samp{--entry} switch, in that it sets the program's starting address.
+But it also sets the bottom bit of the address, so that it can be
+branched to using a BX instruction, and the program will start
+executing in Thumb mode straight away.
+
+@node HPPA ELF32
+@section @code{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
+import stubs suitable for use with a single sub-space application.
+The @samp{--multi-subspace} switch causes @code{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
+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 stub section may serve two groups of input sections, one group before
+the stub section, and one group after it. However, when using
+conditional branches that require stubs, it may be better (for branch
+prediction) that stub sections only serve one group of input sections.
+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
+detected, with the same behaviour regarding stub placement as other
+positive or negative values of @samp{N} respectively.
+
+Note that @samp{--stub-group-size} does not split input sections. A
+single input section larger than the group size specified will of course
+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 TICOFF
+@node TI COFF
+@section @code{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
+header format depends on the default specified by the specific target.
+@end ifset
+
@ifclear GENERIC
@lowersections
@end ifclear
distribution.
Otherwise, send bug reports for @code{ld} to
-@samp{bug-gnu-utils@@gnu.org}.
+@samp{bug-binutils@@gnu.org}.
The fundamental principle of reporting bugs usefully is this:
@strong{report all the facts}. If you are not sure whether to state a
@cindex @code{FORMAT} (MRI)
@item FORMAT @var{output-format}
Similar to the @code{OUTPUT_FORMAT} command in the more general linker
-language, but restricted to one of these output formats:
+language, but restricted to one of these output formats:
@enumerate
-@item
+@item
S-records, if @var{output-format} is @samp{S}
@item
@var{secname}, only the @emph{first} sets the start address.
@end table
+@node GNU Free Documentation License
+@appendix GNU Free Documentation License
+@cindex GNU Free Documentation License
+
+ GNU Free Documentation License
+
+ Version 1.1, March 2000
+
+ Copyright (C) 2000 Free Software Foundation, Inc.
+ 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+
+ Everyone is permitted to copy and distribute verbatim copies
+ of this license document, but changing it is not allowed.
+
+
+0. PREAMBLE
+
+The purpose of this License is to make a manual, textbook, or other
+written document "free" in the sense of freedom: to assure everyone
+the effective freedom to copy and redistribute it, with or without
+modifying it, either commercially or noncommercially. Secondarily,
+this License preserves for the author and publisher a way to get
+credit for their work, while not being considered responsible for
+modifications made by others.
+
+This License is a kind of "copyleft", which means that derivative
+works of the document must themselves be free in the same sense. It
+complements the GNU General Public License, which is a copyleft
+license designed for free software.
+
+We have designed this License in order to use it for manuals for free
+software, because free software needs free documentation: a free
+program should come with manuals providing the same freedoms that the
+software does. But this License is not limited to software manuals;
+it can be used for any textual work, regardless of subject matter or
+whether it is published as a printed book. We recommend this License
+principally for works whose purpose is instruction or reference.
+
+
+1. APPLICABILITY AND DEFINITIONS
+
+This License applies to any manual or other work that contains a
+notice placed by the copyright holder saying it can be distributed
+under the terms of this License. The "Document", below, refers to any
+such manual or work. Any member of the public is a licensee, and is
+addressed as "you".
+
+A "Modified Version" of the Document means any work containing the
+Document or a portion of it, either copied verbatim, or with
+modifications and/or translated into another language.
+
+A "Secondary Section" is a named appendix or a front-matter section of
+the Document that deals exclusively with the relationship of the
+publishers or authors of the Document to the Document's overall subject
+(or to related matters) and contains nothing that could fall directly
+within that overall subject. (For example, if the Document is in part a
+textbook of mathematics, a Secondary Section may not explain any
+mathematics.) The relationship could be a matter of historical
+connection with the subject or with related matters, or of legal,
+commercial, philosophical, ethical or political position regarding
+them.
+
+The "Invariant Sections" are certain Secondary Sections whose titles
+are designated, as being those of Invariant Sections, in the notice
+that says that the Document is released under this License.
+
+The "Cover Texts" are certain short passages of text that are listed,
+as Front-Cover Texts or Back-Cover Texts, in the notice that says that
+the Document is released under this License.
+
+A "Transparent" copy of the Document means a machine-readable copy,
+represented in a format whose specification is available to the
+general public, whose contents can be viewed and edited directly and
+straightforwardly with generic text editors or (for images composed of
+pixels) generic paint programs or (for drawings) some widely available
+drawing editor, and that is suitable for input to text formatters or
+for automatic translation to a variety of formats suitable for input
+to text formatters. A copy made in an otherwise Transparent file
+format whose markup has been designed to thwart or discourage
+subsequent modification by readers is not Transparent. A copy that is
+not "Transparent" is called "Opaque".
+
+Examples of suitable formats for Transparent copies include plain
+ASCII without markup, Texinfo input format, LaTeX input format, SGML
+or XML using a publicly available DTD, and standard-conforming simple
+HTML designed for human modification. Opaque formats include
+PostScript, PDF, proprietary formats that can be read and edited only
+by proprietary word processors, SGML or XML for which the DTD and/or
+processing tools are not generally available, and the
+machine-generated HTML produced by some word processors for output
+purposes only.
+
+The "Title Page" means, for a printed book, the title page itself,
+plus such following pages as are needed to hold, legibly, the material
+this License requires to appear in the title page. For works in
+formats which do not have any title page as such, "Title Page" means
+the text near the most prominent appearance of the work's title,
+preceding the beginning of the body of the text.
+
+
+2. VERBATIM COPYING
+
+You may copy and distribute the Document in any medium, either
+commercially or noncommercially, provided that this License, the
+copyright notices, and the license notice saying this License applies
+to the Document are reproduced in all copies, and that you add no other
+conditions whatsoever to those of this License. You may not use
+technical measures to obstruct or control the reading or further
+copying of the copies you make or distribute. However, you may accept
+compensation in exchange for copies. If you distribute a large enough
+number of copies you must also follow the conditions in section 3.
+
+You may also lend copies, under the same conditions stated above, and
+you may publicly display copies.
+
+
+3. COPYING IN QUANTITY
+
+If you publish printed copies of the Document numbering more than 100,
+and the Document's license notice requires Cover Texts, you must enclose
+the copies in covers that carry, clearly and legibly, all these Cover
+Texts: Front-Cover Texts on the front cover, and Back-Cover Texts on
+the back cover. Both covers must also clearly and legibly identify
+you as the publisher of these copies. The front cover must present
+the full title with all words of the title equally prominent and
+visible. You may add other material on the covers in addition.
+Copying with changes limited to the covers, as long as they preserve
+the title of the Document and satisfy these conditions, can be treated
+as verbatim copying in other respects.
+
+If the required texts for either cover are too voluminous to fit
+legibly, you should put the first ones listed (as many as fit
+reasonably) on the actual cover, and continue the rest onto adjacent
+pages.
+
+If you publish or distribute Opaque copies of the Document numbering
+more than 100, you must either include a machine-readable Transparent
+copy along with each Opaque copy, or state in or with each Opaque copy
+a publicly-accessible computer-network location containing a complete
+Transparent copy of the Document, free of added material, which the
+general network-using public has access to download anonymously at no
+charge using public-standard network protocols. If you use the latter
+option, you must take reasonably prudent steps, when you begin
+distribution of Opaque copies in quantity, to ensure that this
+Transparent copy will remain thus accessible at the stated location
+until at least one year after the last time you distribute an Opaque
+copy (directly or through your agents or retailers) of that edition to
+the public.
+
+It is requested, but not required, that you contact the authors of the
+Document well before redistributing any large number of copies, to give
+them a chance to provide you with an updated version of the Document.
+
+
+4. MODIFICATIONS
+
+You may copy and distribute a Modified Version of the Document under
+the conditions of sections 2 and 3 above, provided that you release
+the Modified Version under precisely this License, with the Modified
+Version filling the role of the Document, thus licensing distribution
+and modification of the Modified Version to whoever possesses a copy
+of it. In addition, you must do these things in the Modified Version:
+
+A. Use in the Title Page (and on the covers, if any) a title distinct
+ from that of the Document, and from those of previous versions
+ (which should, if there were any, be listed in the History section
+ of the Document). You may use the same title as a previous version
+ if the original publisher of that version gives permission.
+B. List on the Title Page, as authors, one or more persons or entities
+ responsible for authorship of the modifications in the Modified
+ Version, together with at least five of the principal authors of the
+ Document (all of its principal authors, if it has less than five).
+C. State on the Title page the name of the publisher of the
+ Modified Version, as the publisher.
+D. Preserve all the copyright notices of the Document.
+E. Add an appropriate copyright notice for your modifications
+ adjacent to the other copyright notices.
+F. Include, immediately after the copyright notices, a license notice
+ giving the public permission to use the Modified Version under the
+ terms of this License, in the form shown in the Addendum below.
+G. Preserve in that license notice the full lists of Invariant Sections
+ and required Cover Texts given in the Document's license notice.
+H. Include an unaltered copy of this License.
+I. Preserve the section entitled "History", and its title, and add to
+ it an item stating at least the title, year, new authors, and
+ publisher of the Modified Version as given on the Title Page. If
+ there is no section entitled "History" in the Document, create one
+ stating the title, year, authors, and publisher of the Document as
+ given on its Title Page, then add an item describing the Modified
+ Version as stated in the previous sentence.
+J. Preserve the network location, if any, given in the Document for
+ public access to a Transparent copy of the Document, and likewise
+ the network locations given in the Document for previous versions
+ it was based on. These may be placed in the "History" section.
+ You may omit a network location for a work that was published at
+ least four years before the Document itself, or if the original
+ publisher of the version it refers to gives permission.
+K. In any section entitled "Acknowledgements" or "Dedications",
+ preserve the section's title, and preserve in the section all the
+ substance and tone of each of the contributor acknowledgements
+ and/or dedications given therein.
+L. Preserve all the Invariant Sections of the Document,
+ unaltered in their text and in their titles. Section numbers
+ or the equivalent are not considered part of the section titles.
+M. Delete any section entitled "Endorsements". Such a section
+ may not be included in the Modified Version.
+N. Do not retitle any existing section as "Endorsements"
+ or to conflict in title with any Invariant Section.
+
+If the Modified Version includes new front-matter sections or
+appendices that qualify as Secondary Sections and contain no material
+copied from the Document, you may at your option designate some or all
+of these sections as invariant. To do this, add their titles to the
+list of Invariant Sections in the Modified Version's license notice.
+These titles must be distinct from any other section titles.
+
+You may add a section entitled "Endorsements", provided it contains
+nothing but endorsements of your Modified Version by various
+parties--for example, statements of peer review or that the text has
+been approved by an organization as the authoritative definition of a
+standard.
+
+You may add a passage of up to five words as a Front-Cover Text, and a
+passage of up to 25 words as a Back-Cover Text, to the end of the list
+of Cover Texts in the Modified Version. Only one passage of
+Front-Cover Text and one of Back-Cover Text may be added by (or
+through arrangements made by) any one entity. If the Document already
+includes a cover text for the same cover, previously added by you or
+by arrangement made by the same entity you are acting on behalf of,
+you may not add another; but you may replace the old one, on explicit
+permission from the previous publisher that added the old one.
+
+The author(s) and publisher(s) of the Document do not by this License
+give permission to use their names for publicity for or to assert or
+imply endorsement of any Modified Version.
+
+
+5. COMBINING DOCUMENTS
+
+You may combine the Document with other documents released under this
+License, under the terms defined in section 4 above for modified
+versions, provided that you include in the combination all of the
+Invariant Sections of all of the original documents, unmodified, and
+list them all as Invariant Sections of your combined work in its
+license notice.
+
+The combined work need only contain one copy of this License, and
+multiple identical Invariant Sections may be replaced with a single
+copy. If there are multiple Invariant Sections with the same name but
+different contents, make the title of each such section unique by
+adding at the end of it, in parentheses, the name of the original
+author or publisher of that section if known, or else a unique number.
+Make the same adjustment to the section titles in the list of
+Invariant Sections in the license notice of the combined work.
+
+In the combination, you must combine any sections entitled "History"
+in the various original documents, forming one section entitled
+"History"; likewise combine any sections entitled "Acknowledgements",
+and any sections entitled "Dedications". You must delete all sections
+entitled "Endorsements."
+
+
+6. COLLECTIONS OF DOCUMENTS
+
+You may make a collection consisting of the Document and other documents
+released under this License, and replace the individual copies of this
+License in the various documents with a single copy that is included in
+the collection, provided that you follow the rules of this License for
+verbatim copying of each of the documents in all other respects.
+
+You may extract a single document from such a collection, and distribute
+it individually under this License, provided you insert a copy of this
+License into the extracted document, and follow this License in all
+other respects regarding verbatim copying of that document.
+
+
+7. AGGREGATION WITH INDEPENDENT WORKS
+
+A compilation of the Document or its derivatives with other separate
+and independent documents or works, in or on a volume of a storage or
+distribution medium, does not as a whole count as a Modified Version
+of the Document, provided no compilation copyright is claimed for the
+compilation. Such a compilation is called an "aggregate", and this
+License does not apply to the other self-contained works thus compiled
+with the Document, on account of their being thus compiled, if they
+are not themselves derivative works of the Document.
+
+If the Cover Text requirement of section 3 is applicable to these
+copies of the Document, then if the Document is less than one quarter
+of the entire aggregate, the Document's Cover Texts may be placed on
+covers that surround only the Document within the aggregate.
+Otherwise they must appear on covers around the whole aggregate.
+
+
+8. TRANSLATION
+
+Translation is considered a kind of modification, so you may
+distribute translations of the Document under the terms of section 4.
+Replacing Invariant Sections with translations requires special
+permission from their copyright holders, but you may include
+translations of some or all Invariant Sections in addition to the
+original versions of these Invariant Sections. You may include a
+translation of this License provided that you also include the
+original English version of this License. In case of a disagreement
+between the translation and the original English version of this
+License, the original English version will prevail.
+
+
+9. TERMINATION
+
+You may not copy, modify, sublicense, or distribute the Document except
+as expressly provided for under this License. Any other attempt to
+copy, modify, sublicense or distribute the Document is void, and will
+automatically terminate your rights under this License. However,
+parties who have received copies, or rights, from you under this
+License will not have their licenses terminated so long as such
+parties remain in full compliance.
+
+
+10. FUTURE REVISIONS OF THIS LICENSE
+
+The Free Software Foundation may publish new, revised versions
+of the GNU Free Documentation License from time to time. Such new
+versions will be similar in spirit to the present version, but may
+differ in detail to address new problems or concerns. See
+http://www.gnu.org/copyleft/.
+
+Each version of the License is given a distinguishing version number.
+If the Document specifies that a particular numbered version of this
+License "or any later version" applies to it, you have the option of
+following the terms and conditions either of that specified version or
+of any later version that has been published (not as a draft) by the
+Free Software Foundation. If the Document does not specify a version
+number of this License, you may choose any version ever published (not
+as a draft) by the Free Software Foundation.
+
+
+ADDENDUM: How to use this License for your documents
+
+To use this License in a document you have written, include a copy of
+the License in the document and put the following copyright and
+license notices just after the title page:
+
+@smallexample
+ Copyright (c) YEAR YOUR NAME.
+ Permission is granted to copy, distribute and/or modify this document
+ under the terms of the GNU Free Documentation License, Version 1.1
+ or any later version published by the Free Software Foundation;
+ with the Invariant Sections being LIST THEIR TITLES, with the
+ Front-Cover Texts being LIST, and with the Back-Cover Texts being LIST.
+ A copy of the license is included in the section entitled "GNU
+ Free Documentation License".
+@end smallexample
+
+If you have no Invariant Sections, write "with no Invariant Sections"
+instead of saying which ones are invariant. If you have no
+Front-Cover Texts, write "no Front-Cover Texts" instead of
+"Front-Cover Texts being LIST"; likewise for Back-Cover Texts.
+
+If your document contains nontrivial examples of program code, we
+recommend releasing these examples in parallel under your choice of
+free software license, such as the GNU General Public License,
+to permit their use in free software.
+
@node Index
@unnumbered Index
@contents
@bye
-
-