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authorbapt <bapt@FreeBSD.org>2015-01-04 00:58:30 +0000
committerbapt <bapt@FreeBSD.org>2015-01-04 00:58:30 +0000
commit6947e68c2d0b3f89be0bdf9b0ef84502bf18027d (patch)
tree8a96c88ad6e18cb490442897926a87f349d66802 /contrib/binutils/ld
parentfdb01c77003977d286c195a7d5c8d4d0e0277df6 (diff)
downloadFreeBSD-src-6947e68c2d0b3f89be0bdf9b0ef84502bf18027d.zip
FreeBSD-src-6947e68c2d0b3f89be0bdf9b0ef84502bf18027d.tar.gz
Add pregenerated documentation for as(1) and ld(1)
Diffstat (limited to 'contrib/binutils/ld')
-rw-r--r--contrib/binutils/ld/configdoc.texi25
-rw-r--r--contrib/binutils/ld/ld.txt6564
2 files changed, 6589 insertions, 0 deletions
diff --git a/contrib/binutils/ld/configdoc.texi b/contrib/binutils/ld/configdoc.texi
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+@c ------------------------------ CONFIGURATION VARS:
+@c 1. Inclusiveness of this manual
+@set GENERIC
+
+@c 2. Specific target machines
+@set ARM
+@set H8300
+@set HPPA
+@set I960
+@set M68HC11
+@set MMIX
+@set MSP430
+@set POWERPC
+@set POWERPC64
+@set Renesas
+@set SPU
+@set TICOFF
+@set WIN32
+@set XTENSA
+
+@c 3. Properties of this configuration
+@clear SingleFormat
+@set UsesEnvVars
+@c ------------------------------ end CONFIGURATION VARS
+
diff --git a/contrib/binutils/ld/ld.txt b/contrib/binutils/ld/ld.txt
new file mode 100644
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--- /dev/null
+++ b/contrib/binutils/ld/ld.txt
@@ -0,0 +1,6564 @@
+START-INFO-DIR-ENTRY
+* Ld: (ld). The GNU linker.
+END-INFO-DIR-ENTRY
+
+LD
+1 Overview
+2 Invocation
+ 2.1 Command Line Options
+ 2.1.1 Options Specific to i386 PE Targets
+ 2.1.2 Options specific to Motorola 68HC11 and 68HC12 targets
+ 2.2 Environment Variables
+3 Linker Scripts
+ 3.1 Basic Linker Script Concepts
+ 3.2 Linker Script Format
+ 3.3 Simple Linker Script Example
+ 3.4 Simple Linker Script Commands
+ 3.4.1 Setting the Entry Point
+ 3.4.2 Commands Dealing with Files
+ 3.4.3 Commands Dealing with Object File Formats
+ 3.4.4 Other Linker Script Commands
+ 3.5 Assigning Values to Symbols
+ 3.5.1 Simple Assignments
+ 3.5.2 PROVIDE
+ 3.5.3 PROVIDE_HIDDEN
+ 3.5.4 Source Code Reference
+ 3.6 SECTIONS Command
+ 3.6.1 Output Section Description
+ 3.6.2 Output Section Name
+ 3.6.3 Output Section Address
+ 3.6.4 Input Section Description
+ 3.6.4.1 Input Section Basics
+ 3.6.4.2 Input Section Wildcard Patterns
+ 3.6.4.3 Input Section for Common Symbols
+ 3.6.4.4 Input Section and Garbage Collection
+ 3.6.4.5 Input Section Example
+ 3.6.5 Output Section Data
+ 3.6.6 Output Section Keywords
+ 3.6.7 Output Section Discarding
+ 3.6.8 Output Section Attributes
+ 3.6.8.1 Output Section Type
+ 3.6.8.2 Output Section LMA
+ 3.6.8.3 Forced Output Alignment
+ 3.6.8.4 Forced Input Alignment
+ 3.6.8.5 Output Section Region
+ 3.6.8.6 Output Section Phdr
+ 3.6.8.7 Output Section Fill
+ 3.6.9 Overlay Description
+ 3.7 MEMORY Command
+ 3.8 PHDRS Command
+ 3.9 VERSION Command
+ 3.10 Expressions in Linker Scripts
+ 3.10.1 Constants
+ 3.10.2 Symbol Names
+ 3.10.3 Orphan Sections
+ 3.10.4 The Location Counter
+ 3.10.5 Operators
+ 3.10.6 Evaluation
+ 3.10.7 The Section of an Expression
+ 3.10.8 Builtin Functions
+ 3.11 Implicit Linker Scripts
+4 Machine Dependent Features
+ 4.1 'ld' and the H8/300
+ 4.2 'ld' and the Intel 960 Family
+ 4.3 'ld' and the Motorola 68HC11 and 68HC12 families
+ 4.3.1 Linker Relaxation
+ 4.3.2 Trampoline Generation
+ 4.4 'ld' and the ARM family
+ 4.5 'ld' and HPPA 32-bit ELF Support
+ 4.6 'ld' and MMIX
+ 4.7 'ld' and MSP430
+ 4.8 'ld' and PowerPC 32-bit ELF Support
+ 4.9 'ld' and PowerPC64 64-bit ELF Support
+ 4.10 'ld' and SPU ELF Support
+ 4.11 'ld''s Support for Various TI COFF Versions
+ 4.12 'ld' and WIN32 (cygwin/mingw)
+ 4.13 'ld' and Xtensa Processors
+5 BFD
+ 5.1 How It Works: An Outline of BFD
+ 5.1.1 Information Loss
+ 5.1.2 The BFD canonical object-file format
+6 Reporting Bugs
+ 6.1 Have You Found a Bug?
+ 6.2 How to Report Bugs
+Appendix A MRI Compatible Script Files
+Appendix B GNU Free Documentation License
+ ADDENDUM: How to use this License for your documents
+LD Index
+LD
+**
+
+This file documents the GNU linker ld version "2.17.50 [FreeBSD]
+2007-07-03".
+
+ 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".
+
+1 Overview
+**********
+
+'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 'ld'.
+
+ '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.
+
+ This version of 'ld' uses the general purpose BFD libraries to
+operate on object files. This allows 'ld' to read, combine, and write
+object files in many different formats--for example, COFF or 'a.out'.
+Different formats may be linked together to produce any available kind
+of object file. *Note BFD::, for more information.
+
+ Aside from its flexibility, the GNU linker is more helpful than other
+linkers in providing diagnostic information. Many linkers abandon
+execution immediately upon encountering an error; whenever possible,
+'ld' continues executing, allowing you to identify other errors (or, in
+some cases, to get an output file in spite of the error).
+
+2 Invocation
+************
+
+The GNU linker '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.
+
+2.1 Command Line Options
+========================
+
+The linker supports a plethora of command-line options, but in actual
+practice few of them are used in any particular context. For instance,
+a frequent use of 'ld' is to link standard Unix object files on a
+standard, supported Unix system. On such a system, to link a file
+'hello.o':
+
+ ld -o OUTPUT /lib/crt0.o hello.o -lc
+
+ This tells 'ld' to produce a file called OUTPUT as the result of
+linking the file '/lib/crt0.o' with 'hello.o' and the library 'libc.a',
+which will come from the standard search directories. (See the
+discussion of the '-l' option below.)
+
+ Some of the command-line options to 'ld' may be specified at any
+point in the command line. However, options which refer to files, such
+as '-l' or '-T', cause the file to be read at the point at which the
+option appears in the command line, relative to the object files and
+other file options. Repeating non-file options with a different
+argument will either have no further effect, or override prior
+occurrences (those further to the left on the command line) of that
+option. Options which may be meaningfully specified more than once are
+noted in the descriptions below.
+
+ Non-option arguments are object files or archives which are to be
+linked together. They may follow, precede, or be mixed in with
+command-line options, except that an object file argument may not be
+placed between an option and its argument.
+
+ Usually the linker is invoked with at least one object file, but you
+can specify other forms of binary input files using '-l', '-R', and the
+script command language. If _no_ binary input files at all are
+specified, the linker does not produce any output, and issues the
+message 'No input files'.
+
+ If the linker cannot recognize the format of an object file, it will
+assume that it is a linker script. A script specified in this way
+augments the main linker script used for the link (either the default
+linker script or the one specified by using '-T'). This feature 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 'INPUT'
+or 'GROUP' to load other objects. Note that specifying a script in this
+way merely augments the main linker script; use the '-T' option to
+replace the default linker script entirely. *Note Scripts::.
+
+ For options whose names are a single letter, option arguments must
+either follow the option letter without intervening whitespace, or be
+given as separate arguments immediately following the option that
+requires them.
+
+ For options whose names are multiple letters, either one dash or two
+can precede the option name; for example, '-trace-symbol' and
+'--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 preceded by two dashes. This is to reduce confusion with the '-o'
+option. So for example '-omagic' sets the output file name to 'magic'
+whereas '--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,
+'--trace-symbol foo' and '--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 (e.g. 'gcc') then all the linker command line options should be
+prefixed by '-Wl,' (or whatever is appropriate for the particular
+compiler driver) like this:
+
+ gcc -Wl,--startgroup foo.o bar.o -Wl,--endgroup
+
+ 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:
+
+'@FILE'
+ Read command-line options from FILE. The options read are inserted
+ in place of the original @FILE option. If FILE does not exist, or
+ cannot be read, then the option will be treated literally, and not
+ removed.
+
+ Options in FILE are separated by whitespace. A whitespace
+ character may be included in an option by surrounding the entire
+ option in either single or double quotes. Any character (including
+ a backslash) may be included by prefixing the character to be
+ included with a backslash. The FILE may itself contain additional
+ @FILE options; any such options will be processed recursively.
+
+'-aKEYWORD'
+ This option is supported for HP/UX compatibility. The KEYWORD
+ argument must be one of the strings 'archive', 'shared', or
+ 'default'. '-aarchive' is functionally equivalent to '-Bstatic',
+ and the other two keywords are functionally equivalent to
+ '-Bdynamic'. This option may be used any number of times.
+
+'-AARCHITECTURE'
+'--architecture=ARCHITECTURE'
+ In the current release of 'ld', this option is useful only for the
+ Intel 960 family of architectures. In that 'ld' configuration, the
+ ARCHITECTURE argument identifies the particular architecture in the
+ 960 family, enabling some safeguards and modifying the
+ archive-library search path. *Note 'ld' and the Intel 960 family:
+ i960, for details.
+
+ Future releases of 'ld' may support similar functionality for other
+ architecture families.
+
+'-b INPUT-FORMAT'
+'--format=INPUT-FORMAT'
+ 'ld' may be configured to support more than one kind of object
+ file. If your 'ld' is configured this way, you can use the '-b'
+ option to specify the binary format for input object files that
+ follow this option on the command line. Even when 'ld' is
+ configured to support alternative object formats, you don't usually
+ need to specify this, as 'ld' should be configured to expect as a
+ default input format the most usual format on each machine.
+ INPUT-FORMAT is a text string, the name of a particular format
+ supported by the BFD libraries. (You can list the available binary
+ formats with 'objdump -i'.) *Note BFD::.
+
+ You may want to use this option if you are linking files with an
+ unusual binary format. You can also use '-b' to switch formats
+ explicitly (when linking object files of different formats), by
+ including '-b INPUT-FORMAT' before each group of object files in a
+ particular format.
+
+ The default format is taken from the environment variable
+ 'GNUTARGET'. *Note Environment::. You can also define the input
+ format from a script, using the command 'TARGET'; see *note Format
+ Commands::.
+
+'-c MRI-COMMANDFILE'
+'--mri-script=MRI-COMMANDFILE'
+ For compatibility with linkers produced by MRI, 'ld' accepts script
+ files written in an alternate, restricted command language,
+ described in *note MRI Compatible Script Files: MRI. Introduce MRI
+ script files with the option '-c'; use the '-T' option to run
+ linker scripts written in the general-purpose 'ld' scripting
+ language. If MRI-CMDFILE does not exist, 'ld' looks for it in the
+ directories specified by any '-L' options.
+
+'-d'
+'-dc'
+'-dp'
+ These three options are equivalent; multiple forms are supported
+ for compatibility with other linkers. They assign space to common
+ symbols even if a relocatable output file is specified (with '-r').
+ The script command 'FORCE_COMMON_ALLOCATION' has the same effect.
+ *Note Miscellaneous Commands::.
+
+'-e ENTRY'
+'--entry=ENTRY'
+ Use ENTRY as the explicit symbol for beginning execution of your
+ program, rather than the default entry point. If there is no
+ symbol named ENTRY, the linker will try to parse ENTRY as a number,
+ and use that as the entry address (the number will be interpreted
+ in base 10; you may use a leading '0x' for base 16, or a leading
+ '0' for base 8). *Note Entry Point::, for a discussion of defaults
+ and other ways of specifying the entry point.
+
+'--exclude-libs LIB,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 '--exclude-libs ALL' excludes symbols
+ in all archive libraries from automatic export. This option is
+ available only for the i386 PE targeted port of the linker and for
+ ELF targeted ports. For i386 PE, symbols explicitly listed in a
+ .def file are still exported, regardless of this option. For ELF
+ targeted ports, symbols affected by this option will be treated as
+ hidden.
+
+'-E'
+'--export-dynamic'
+ When creating a dynamically linked executable, add all symbols to
+ the dynamic symbol table. The dynamic symbol table is the set of
+ symbols which are visible from dynamic objects at run time.
+
+ If you do not use this option, the dynamic symbol table will
+ normally contain only those symbols which are referenced by some
+ dynamic object mentioned in the link.
+
+ If you use 'dlopen' to load a dynamic object which needs to refer
+ back to the symbols defined by the program, rather than some other
+ dynamic object, then you will probably need to use this option when
+ linking the program itself.
+
+ You can also use the dynamic list to control what symbols should be
+ added to the dynamic symbol table if the output format supports it.
+ See the description of '--dynamic-list'.
+
+'-EB'
+ Link big-endian objects. This affects the default output format.
+
+'-EL'
+ Link little-endian objects. This affects the default output
+ format.
+
+'-f'
+'--auxiliary NAME'
+ When creating an ELF shared object, set the internal DT_AUXILIARY
+ field to the specified name. This tells the dynamic linker that
+ the symbol table of the shared object should be used as an
+ auxiliary filter on the symbol table of the shared object NAME.
+
+ If you later link a program against this filter object, then, when
+ you run the program, the dynamic linker will see the DT_AUXILIARY
+ field. If the dynamic linker resolves any symbols from the filter
+ object, it will first check whether there is a definition in the
+ shared object NAME. If there is one, it will be used instead of
+ the definition in the filter object. The shared object NAME need
+ not exist. Thus the shared object NAME may be used to provide an
+ alternative implementation of certain functions, perhaps for
+ debugging or for machine specific performance.
+
+ This option may be specified more than once. The DT_AUXILIARY
+ entries will be created in the order in which they appear on the
+ command line.
+
+'-F NAME'
+'--filter NAME'
+ When creating an ELF shared object, set the internal DT_FILTER
+ field to the specified name. This tells the dynamic linker that
+ the symbol table of the shared object which is being created should
+ be used as a filter on the symbol table of the shared object NAME.
+
+ If you later link a program against this filter object, then, when
+ you run the program, the dynamic linker will see the DT_FILTER
+ field. The dynamic linker will resolve symbols according to the
+ symbol table of the filter object as usual, but it will actually
+ link to the definitions found in the shared object NAME. Thus the
+ filter object can be used to select a subset of the symbols
+ provided by the object NAME.
+
+ Some older linkers used the '-F' option throughout a compilation
+ toolchain for specifying object-file format for both input and
+ output object files. The GNU linker uses other mechanisms for this
+ purpose: the '-b', '--format', '--oformat' options, the 'TARGET'
+ command in linker scripts, and the 'GNUTARGET' environment
+ variable. The GNU linker will ignore the '-F' option when not
+ creating an ELF shared object.
+
+'-fini 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 '_fini'
+ as the function to call.
+
+'-g'
+ Ignored. Provided for compatibility with other tools.
+
+'-GVALUE'
+'--gpsize=VALUE'
+ Set the maximum size of objects to be optimized using the GP
+ register to SIZE. This is only meaningful for object file formats
+ such as MIPS ECOFF which supports putting large and small objects
+ into different sections. This is ignored for other object file
+ formats.
+
+'-hNAME'
+'-soname=NAME'
+ When creating an ELF shared object, set the internal DT_SONAME
+ field to the specified name. When an executable is linked with a
+ shared object which has a DT_SONAME field, then when the executable
+ is run the dynamic linker will attempt to load the shared object
+ specified by the DT_SONAME field rather than the using the file
+ name given to the linker.
+
+'-i'
+ Perform an incremental link (same as option '-r').
+
+'-init 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 '_init'
+ as the function to call.
+
+'-lNAMESPEC'
+'--library=NAMESPEC'
+ Add the archive or object file specified by NAMESPEC to the list of
+ files to link. This option may be used any number of times. If
+ NAMESPEC is of the form ':FILENAME', 'ld' will search the library
+ path for a file called FILENAME, otherise it will search the
+ library path for a file called 'libNAMESPEC.a'.
+
+ On systems which support shared libraries, 'ld' may also search for
+ files other than 'libNAMESPEC.a'. Specifically, on ELF and SunOS
+ systems, 'ld' will search a directory for a library called
+ 'libNAMESPEC.so' before searching for one called 'libNAMESPEC.a'.
+ (By convention, a '.so' extension indicates a shared library.)
+ Note that this behavior does not apply to ':FILENAME', which always
+ specifies a file called FILENAME.
+
+ The linker will search an archive only once, at the location where
+ it is specified on the command line. If the archive defines a
+ symbol which was undefined in some object which appeared before the
+ archive on the command line, the linker will include the
+ appropriate file(s) from the 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 '-(' 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.
+
+ This type of archive searching is standard for Unix linkers.
+ However, if you are using 'ld' on AIX, note that it is different
+ from the behaviour of the AIX linker.
+
+'-LSEARCHDIR'
+'--library-path=SEARCHDIR'
+ Add path SEARCHDIR to the list of paths that 'ld' will search for
+ archive libraries and '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 '-L' options apply to all '-l' options,
+ regardless of the order in which the options appear.
+
+ If SEARCHDIR begins with '=', then the '=' will be replaced by the
+ "sysroot prefix", a path specified when the linker is configured.
+
+ The default set of paths searched (without being specified with
+ '-L') depends on which emulation mode 'ld' is using, and in some
+ cases also on how it was configured. *Note Environment::.
+
+ The paths can also be specified in a link script with the
+ 'SEARCH_DIR' command. Directories specified this way are searched
+ at the point in which the linker script appears in the command
+ line.
+
+'-mEMULATION'
+ Emulate the EMULATION linker. You can list the available
+ emulations with the '--verbose' or '-V' options.
+
+ If the '-m' option is not used, the emulation is taken from the
+ 'LDEMULATION' environment variable, if that is defined.
+
+ Otherwise, the default emulation depends upon how the linker was
+ configured.
+
+'-M'
+'--print-map'
+ Print a link map to the standard output. A link map provides
+ information about the link, including the following:
+
+ * Where object files are mapped into memory.
+ * How common symbols are allocated.
+ * All archive members included in the link, with a mention of
+ the symbol which caused the archive member to be brought in.
+ * The values assigned to symbols.
+
+ Note - symbols whose values are computed by an expression
+ which involves a reference to a previous value of the same
+ symbol may not have correct result displayed in the link map.
+ This is because the linker discards intermediate results and
+ only retains the final value of an expression. Under such
+ circumstances the linker will display the final value enclosed
+ by square brackets. Thus for example a linker script
+ containing:
+
+ foo = 1
+ foo = foo * 4
+ foo = foo + 8
+
+ will produce the following output in the link map if the '-M'
+ option is used:
+
+ 0x00000001 foo = 0x1
+ [0x0000000c] foo = (foo * 0x4)
+ [0x0000000c] foo = (foo + 0x8)
+
+ See *note Expressions:: for more information about expressions
+ in linker scripts.
+
+'-n'
+'--nmagic'
+ Turn off page alignment of sections, and mark the output as
+ 'NMAGIC' if possible.
+
+'-N'
+'--omagic'
+ Set the text and data sections to be readable and writable. Also,
+ do 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 'OMAGIC'. Note: Although a writable
+ text section is allowed for PE-COFF targets, it does not conform to
+ the format specification published by Microsoft.
+
+'--no-omagic'
+ This option negates most of the effects of the '-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 '-Bdynamic' for this.
+
+'-o OUTPUT'
+'--output=OUTPUT'
+ Use OUTPUT as the name for the program produced by 'ld'; if this
+ option is not specified, the name 'a.out' is used by default. The
+ script command 'OUTPUT' can also specify the output file name.
+
+'-O LEVEL'
+ If LEVEL is a numeric values greater than zero 'ld' optimizes the
+ output. This might take significantly longer and therefore
+ probably should only be enabled for the final binary.
+
+'-q'
+'--emit-relocs'
+ Leave relocation sections and contents in fully linked executables.
+ Post link analysis and optimization tools may need this information
+ in order to perform correct modifications of executables. This
+ results in larger executables.
+
+ This option is currently only supported on ELF platforms.
+
+'--force-dynamic'
+ Force the output file to have dynamic sections. This option is
+ specific to VxWorks targets.
+
+'-r'
+'--relocatable'
+ Generate relocatable output--i.e., generate an output file that can
+ in turn serve as input to 'ld'. This is often called "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 'OMAGIC'. If this option is not specified, an absolute
+ file is produced. When linking C++ programs, this option _will
+ not_ resolve references to constructors; to do that, use '-Ur'.
+
+ When an input file does not have the same format as the output
+ file, partial linking is only supported if that input file does not
+ contain any relocations. Different output formats can have further
+ restrictions; for example some 'a.out'-based formats do not support
+ partial linking with input files in other formats at all.
+
+ This option does the same thing as '-i'.
+
+'-R FILENAME'
+'--just-symbols=FILENAME'
+ Read symbol names and their addresses from FILENAME, but do not
+ relocate it or include it in the output. This allows your output
+ file 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 '-R' option is
+ followed by a directory name, rather than a file name, it is
+ treated as the '-rpath' option.
+
+'-s'
+'--strip-all'
+ Omit all symbol information from the output file.
+
+'-S'
+'--strip-debug'
+ Omit debugger symbol information (but not all symbols) from the
+ output file.
+
+'-t'
+'--trace'
+ Print the names of the input files as 'ld' processes them.
+
+'-T SCRIPTFILE'
+'--script=SCRIPTFILE'
+ Use SCRIPTFILE as the linker script. This script replaces 'ld''s
+ default linker script (rather than adding to it), so COMMANDFILE
+ must specify everything necessary to describe the output file.
+ *Note Scripts::. If SCRIPTFILE does not exist in the current
+ directory, 'ld' looks for it in the directories specified by any
+ preceding '-L' options. Multiple '-T' options accumulate.
+
+'-dT SCRIPTFILE'
+'--default-script=SCRIPTFILE'
+ Use SCRIPTFILE as the default linker script. *Note Scripts::.
+
+ This option is similar to the '--script' option except that
+ processing of the script is delayed until after the rest of the
+ command line has been processed. This allows options placed after
+ the '--default-script' option on the command line to affect the
+ behaviour of the linker script, which can be important when the
+ linker command line cannot be directly controlled by the user. (eg
+ because the command line is being constructed by another tool, such
+ as 'gcc').
+
+'-u SYMBOL'
+'--undefined=SYMBOL'
+ Force SYMBOL to be entered in the output file as an undefined
+ symbol. Doing this may, for example, trigger linking of additional
+ modules from standard libraries. '-u' may be repeated with
+ different option arguments to enter additional undefined symbols.
+ This option is equivalent to the 'EXTERN' linker script command.
+
+'-Ur'
+ For anything other than C++ programs, this option is equivalent to
+ '-r': it generates relocatable output--i.e., an output file that
+ can in turn serve as input to 'ld'. When linking C++ programs,
+ '-Ur' _does_ resolve references to constructors, unlike '-r'. It
+ does not work to use '-Ur' on files that were themselves linked
+ with '-Ur'; once the constructor table has been built, it cannot be
+ added to. Use '-Ur' only for the last partial link, and '-r' for
+ the others.
+
+'--unique[=SECTION]'
+ Creates a separate output section for every input section matching
+ SECTION, or if the optional wildcard 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.
+
+'-v'
+'--version'
+'-V'
+ Display the version number for 'ld'. The '-V' option also lists
+ the supported emulations.
+
+'-x'
+'--discard-all'
+ Delete all local symbols.
+
+'-X'
+'--discard-locals'
+ Delete all temporary local symbols. (These symbols start with
+ system-specific local label prefixes, typically '.L' for ELF
+ systems or 'L' for traditional a.out systems.)
+
+'-y SYMBOL'
+'--trace-symbol=SYMBOL'
+ Print the name of each linked file in which SYMBOL appears. This
+ option may be given any number of times. On many systems it is
+ necessary to prepend an underscore.
+
+ This option is useful when you have an undefined symbol in your
+ link but don't know where the reference is coming from.
+
+'-Y PATH'
+ Add PATH to the default library search path. This option exists
+ for Solaris compatibility.
+
+'-z KEYWORD'
+ The recognized keywords are:
+
+ 'combreloc'
+ Combines multiple reloc sections and sorts them to make
+ dynamic symbol lookup caching possible.
+
+ 'defs'
+ Disallows undefined symbols in object files. Undefined
+ symbols in shared libraries are still allowed.
+
+ 'execstack'
+ Marks the object as requiring executable stack.
+
+ 'initfirst'
+ This option is only meaningful when building a shared object.
+ It marks the object so that its runtime initialization will
+ occur before the runtime initialization of any other objects
+ brought into the process at the same time. Similarly the
+ runtime finalization of the object will occur after the
+ runtime finalization of any other objects.
+
+ 'interpose'
+ Marks the object that its symbol table interposes before all
+ symbols but the primary executable.
+
+ 'lazy'
+ When generating an executable or shared library, mark it to
+ tell the dynamic linker to defer function call resolution to
+ the point when the function is called (lazy binding), rather
+ than at load time. Lazy binding is the default.
+
+ 'loadfltr'
+ Marks the object that its filters be processed immediately at
+ runtime.
+
+ 'muldefs'
+ Allows multiple definitions.
+
+ 'nocombreloc'
+ Disables multiple reloc sections combining.
+
+ 'nocopyreloc'
+ Disables production of copy relocs.
+
+ 'nodefaultlib'
+ Marks the object that the search for dependencies of this
+ object will ignore any default library search paths.
+
+ 'nodelete'
+ Marks the object shouldn't be unloaded at runtime.
+
+ 'nodlopen'
+ Marks the object not available to 'dlopen'.
+
+ 'nodump'
+ Marks the object can not be dumped by 'dldump'.
+
+ 'noexecstack'
+ Marks the object as not requiring executable stack.
+
+ 'norelro'
+ Don't create an ELF 'PT_GNU_RELRO' segment header in the
+ object.
+
+ 'now'
+ When generating an executable or shared library, mark it to
+ tell the dynamic linker to resolve all symbols when the
+ program is started, or when the shared library is linked to
+ using dlopen, instead of deferring function call resolution to
+ the point when the function is first called.
+
+ 'origin'
+ Marks the object may contain $ORIGIN.
+
+ 'relro'
+ Create an ELF 'PT_GNU_RELRO' segment header in the object.
+
+ 'max-page-size=VALUE'
+ Set the emulation maximum page size to VALUE.
+
+ 'common-page-size=VALUE'
+ Set the emulation common page size to VALUE.
+
+ Other keywords are ignored for Solaris compatibility.
+
+'-( ARCHIVES -)'
+'--start-group ARCHIVES --end-group'
+ The ARCHIVES should be a list of archive files. They may be either
+ explicit file names, or '-l' options.
+
+ The specified archives are searched repeatedly until no new
+ undefined references are created. Normally, an archive is searched
+ only once in the order that it is specified on the command line.
+ If a symbol in that archive is needed to resolve an undefined
+ symbol referred to by an object in an archive that appears later on
+ the command line, the linker would not be able to resolve that
+ reference. By grouping the archives, they all be searched
+ repeatedly until all possible references are resolved.
+
+ Using this option has a significant performance cost. It is best
+ to use it only when there are unavoidable circular references
+ between two or more archives.
+
+'--accept-unknown-input-arch'
+'--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 '--accept-unknown-input-arch' option has
+ been added to restore the old behaviour.
+
+'--as-needed'
+'--no-as-needed'
+ This option affects ELF DT_NEEDED tags for dynamic libraries
+ mentioned on the command line after the '--as-needed' option.
+ Normally, the linker will add a DT_NEEDED tag for each dynamic
+ library mentioned on the command line, regardless of whether the
+ library is actually needed. '--as-needed' causes DT_NEEDED tags to
+ only be emitted for libraries that satisfy some symbol reference
+ from regular objects which is undefined at the point that the
+ library was linked. '--no-as-needed' restores the default
+ behaviour.
+
+'--add-needed'
+'--no-add-needed'
+ This option affects the treatment of dynamic libraries from ELF
+ DT_NEEDED tags in dynamic libraries mentioned on the command line
+ after the '--no-add-needed' option. Normally, the linker will add
+ a DT_NEEDED tag for each dynamic library from DT_NEEDED tags.
+ '--no-add-needed' causes DT_NEEDED tags will never be emitted for
+ those libraries from DT_NEEDED tags. '--add-needed' restores the
+ default behaviour.
+
+'-assert KEYWORD'
+ This option is ignored for SunOS compatibility.
+
+'-Bdynamic'
+'-dy'
+'-call_shared'
+ Link against dynamic libraries. This is only meaningful on
+ platforms for which shared libraries are supported. This option is
+ normally the 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 '-l' options which follow it.
+
+'-Bgroup'
+ Set the 'DF_1_GROUP' flag in the '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.
+ '--unresolved-symbols=report-all' is implied. This option is only
+ meaningful on ELF platforms which support shared libraries.
+
+'-Bstatic'
+'-dn'
+'-non_shared'
+'-static'
+ Do not link against shared libraries. This is only meaningful on
+ 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 '-l' options which follow it. This
+ option also implies '--unresolved-symbols=report-all'. This option
+ can be used with '-shared'. Doing so means that a shared library
+ is being created but that all of the library's external references
+ must be resolved by pulling in entries from static libraries.
+
+'-Bsymbolic'
+ When creating a shared library, bind references to global symbols
+ to the definition within the shared library, if any. Normally, it
+ is possible for a program linked against a shared library to
+ override the definition within the shared library. This option is
+ only meaningful on ELF platforms which support shared libraries.
+
+'-Bsymbolic-functions'
+ When creating a shared library, bind references to global function
+ symbols to the definition within the shared library, if any. This
+ option is only meaningful on ELF platforms which support shared
+ libraries.
+
+'--dynamic-list=DYNAMIC-LIST-FILE'
+ Specify the name of a dynamic list file to the linker. This is
+ typically used when creating shared libraries to specify a list of
+ global symbols whose references shouldn't be bound to the
+ definition within the shared library, or creating dynamically
+ linked executables to specify a list of symbols which should be
+ added to the symbol table in the executable. This option is only
+ meaningful on ELF platforms which support shared libraries.
+
+ The format of the dynamic list is the same as the version node
+ without scope and node name. See *note VERSION:: for more
+ information.
+
+'--dynamic-list-data'
+ Include all global data symbols to the dynamic list.
+
+'--dynamic-list-cpp-new'
+ Provide the builtin dynamic list for C++ operator new and delete.
+ It is mainly useful for building shared libstdc++.
+
+'--dynamic-list-cpp-typeinfo'
+ Provide the builtin dynamic list for C++ runtime type
+ identification.
+
+'--check-sections'
+'--no-check-sections'
+ Asks the linker _not_ to check section addresses after they have
+ been assigned to see if there are any overlaps. Normally the
+ linker will perform this check, and if it finds any overlaps it
+ will produce suitable error messages. The linker does know about,
+ and does make allowances for sections in overlays. The default
+ behaviour can be restored by using the command line switch
+ '--check-sections'.
+
+'--cref'
+ Output a cross reference table. If a linker map file is being
+ generated, the cross reference table is printed to the map file.
+ Otherwise, it is printed on the standard output.
+
+ The format of the table is intentionally simple, so that it may be
+ easily processed by a script if necessary. The symbols are printed
+ out, sorted by name. For each symbol, a list of file names is
+ given. If the symbol is defined, the first file listed is the
+ location of the definition. The remaining files contain references
+ to the symbol.
+
+'--no-define-common'
+ This option inhibits the assignment of addresses to common symbols.
+ The script command 'INHIBIT_COMMON_ALLOCATION' has the same effect.
+ *Note Miscellaneous Commands::.
+
+ The '--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 '--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.
+
+'--defsym SYMBOL=EXPRESSION'
+ Create a global symbol in the output file, containing the absolute
+ address given by EXPRESSION. You may use this option as many times
+ as necessary to define multiple symbols in the command line. A
+ limited form of arithmetic is supported for the EXPRESSION in this
+ context: you may give a hexadecimal constant or the name of an
+ existing symbol, or use '+' and '-' to add or subtract hexadecimal
+ constants or symbols. If you need more elaborate expressions,
+ consider using the linker command language from a script (*note
+ Assignment: Symbol Definitions: Assignments.). _Note:_ there
+ should be no white space between SYMBOL, the equals sign ("<=>"),
+ and EXPRESSION.
+
+'--demangle[=STYLE]'
+'--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.
+ 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 'COLLECT_NO_DEMANGLE' is
+ set. These options may be used to override the default.
+
+'--dynamic-linker FILE'
+ Set the name of the dynamic linker. This is only meaningful when
+ generating dynamically linked ELF executables. The default dynamic
+ linker is normally correct; don't use this unless you know what you
+ are doing.
+
+'--fatal-warnings'
+ Treat all warnings as errors.
+
+'--force-exe-suffix'
+ Make sure that an output file has a .exe suffix.
+
+ If a successfully built fully linked output file does not have a
+ '.exe' or '.dll' suffix, this option forces the linker to copy the
+ output file to one of the same name with a '.exe' suffix. This
+ option is useful when using unmodified Unix makefiles on a
+ Microsoft Windows host, since some versions of Windows won't run an
+ image unless it ends in a '.exe' suffix.
+
+'--gc-sections'
+'--no-gc-sections'
+ Enable garbage collection of unused input sections. It is ignored
+ on targets that do not support this option. This option is not
+ compatible with '-r' or '--emit-relocs'. The default behaviour (of
+ not performing this garbage collection) can be restored by
+ specifying '--no-gc-sections' on the command line.
+
+'--print-gc-sections'
+'--no-print-gc-sections'
+ List all sections removed by garbage collection. The listing is
+ printed on stderr. This option is only effective if garbage
+ collection has been enabled via the '--gc-sections') option. The
+ default behaviour (of not listing the sections that are removed)
+ can be restored by specifying '--no-print-gc-sections' on the
+ command line.
+
+'--help'
+ Print a summary of the command-line options on the standard output
+ and exit.
+
+'--target-help'
+ Print a summary of all target specific options on the standard
+ output and exit.
+
+'-Map MAPFILE'
+ Print a link map to the file MAPFILE. See the description of the
+ '-M' option, above.
+
+'--no-keep-memory'
+ 'ld' normally optimizes for speed over memory usage by caching the
+ symbol tables of input files in memory. This option tells 'ld' to
+ instead optimize for memory usage, by rereading the symbol tables
+ as necessary. This may be required if 'ld' runs out of memory
+ space while linking a large executable.
+
+'--no-undefined'
+'-z defs'
+ Report unresolved symbol references from regular object files.
+ This is done even if the linker is creating a non-symbolic shared
+ library. The switch '--[no-]allow-shlib-undefined' controls the
+ behaviour for reporting unresolved references found in shared
+ libraries being linked in.
+
+'--allow-multiple-definition'
+'-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.
+
+'--allow-shlib-undefined'
+'--no-allow-shlib-undefined'
+ Allows (the default) or disallows undefined symbols in shared
+ libraries. This switch is similar to '--no-undefined' except that
+ it determines the behaviour when the undefined symbols are in a
+ shared library rather than a regular object file. It does not
+ affect how undefined symbols in regular object files are handled.
+
+ The reason that '--allow-shlib-undefined' is the default is that
+ the shared library being specified at link time may not be the same
+ as the 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.
+ (The kernel patches them at load time to select which function is
+ most appropriate for the current architecture. This is used for
+ example to dynamically select an appropriate memset function).
+ Apparently it is also normal for HPPA shared libraries to have
+ undefined symbols.
+
+'--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.
+
+'--default-symver'
+ Create and use a default symbol version (the soname) for
+ unversioned exported symbols.
+
+'--default-imported-symver'
+ Create and use a default symbol version (the soname) for
+ unversioned imported symbols.
+
+'--no-warn-mismatch'
+ Normally '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 '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.
+
+'--no-warn-search-mismatch'
+ Normally 'ld' will give a warning if it finds an incompatible
+ library during a library search. This option silences the warning.
+
+'--no-whole-archive'
+ Turn off the effect of the '--whole-archive' option for subsequent
+ archive files.
+
+'--noinhibit-exec'
+ Retain the executable output file whenever it is still usable.
+ Normally, the linker will not produce an output file if it
+ encounters errors during the link process; it exits without writing
+ an output file when it issues any error whatsoever.
+
+'-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.
+
+'--oformat OUTPUT-FORMAT'
+ 'ld' may be configured to support more than one kind of object
+ file. If your 'ld' is configured this way, you can use the
+ '--oformat' option to specify the binary format for the output
+ object file. Even when 'ld' is configured to support alternative
+ object formats, you don't usually need to specify this, as 'ld'
+ should be configured to produce as a default output format the most
+ usual format on each machine. OUTPUT-FORMAT is a text string, the
+ name of a particular format supported by the BFD libraries. (You
+ can list the available binary formats with 'objdump -i'.) The
+ script command 'OUTPUT_FORMAT' can also specify the output format,
+ but this option overrides it. *Note BFD::.
+
+'-pie'
+'--pic-executable'
+ Create a position independent executable. This is currently only
+ supported on ELF platforms. Position independent executables are
+ similar to shared libraries in that they are relocated by the
+ dynamic linker to the virtual address the OS chooses for them
+ (which can vary between invocations). Like normal dynamically
+ linked executables they can be executed and symbols defined in the
+ executable cannot be overridden by shared libraries.
+
+'-qmagic'
+ This option is ignored for Linux compatibility.
+
+'-Qy'
+ This option is ignored for SVR4 compatibility.
+
+'--relax'
+ An option with machine dependent effects. This option is only
+ supported on a few targets. *Note 'ld' and the H8/300: H8/300.
+ *Note 'ld' and the Intel 960 family: i960. *Note 'ld' and Xtensa
+ Processors: Xtensa. *Note 'ld' and the 68HC11 and 68HC12:
+ M68HC11/68HC12. *Note 'ld' and PowerPC 32-bit ELF Support: PowerPC
+ ELF32.
+
+ On some platforms, the '--relax' option performs global
+ optimizations that become possible when the linker resolves
+ addressing in the program, such as relaxing address modes and
+ synthesizing new instructions in the output object file.
+
+ On some platforms these link time global optimizations may make
+ symbolic debugging of the resulting executable impossible. This is
+ known to be the case for the Matsushita MN10200 and MN10300 family
+ of processors.
+
+ On platforms where this is not supported, '--relax' is accepted,
+ but ignored.
+
+'--retain-symbols-file FILENAME'
+ Retain _only_ the symbols listed in the file FILENAME, discarding
+ all others. FILENAME is simply a flat file, with one symbol name
+ per line. This option is especially useful in environments (such
+ as VxWorks) where a large global symbol table is accumulated
+ gradually, to conserve run-time memory.
+
+ '--retain-symbols-file' does _not_ discard undefined symbols, or
+ symbols needed for relocations.
+
+ You may only specify '--retain-symbols-file' once in the command
+ line. It overrides '-s' and '-S'.
+
+'-rpath DIR'
+ Add a directory to the runtime library search path. This is used
+ when linking an ELF executable with shared objects. All '-rpath'
+ arguments are concatenated and passed to the runtime linker, which
+ uses them to locate shared objects at runtime. The '-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 '-rpath-link' option. If '-rpath' is not used when linking
+ an ELF executable, the contents of the environment variable
+ 'LD_RUN_PATH' will be used if it is defined.
+
+ The '-rpath' option may also be used on SunOS. By default, on
+ SunOS, the linker will form a runtime search patch out of all the
+ '-L' options it is given. If a '-rpath' option is used, the
+ runtime search path will be formed exclusively using the '-rpath'
+ options, ignoring the '-L' options. This can be useful when using
+ gcc, which adds many '-L' options which may be on NFS mounted file
+ systems.
+
+ For compatibility with other ELF linkers, if the '-R' option is
+ followed by a directory name, rather than a file name, it is
+ treated as the '-rpath' option.
+
+'-rpath-link DIR'
+ When using ELF or SunOS, one shared library may require another.
+ This happens when an 'ld -shared' link includes a shared library as
+ one of the input files.
+
+ 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 '-rpath-link'
+ option specifies the first set of directories to search. The
+ '-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.
+
+ 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:
+ 1. Any directories specified by '-rpath-link' options.
+ 2. Any directories specified by '-rpath' options. The difference
+ between '-rpath' and '-rpath-link' is that directories
+ specified by '-rpath' options are included in the executable
+ and used at runtime, whereas the '-rpath-link' option is only
+ effective at link time. Searching '-rpath' in this way is
+ only supported by native linkers and cross linkers which have
+ been configured with the '--with-sysroot' option.
+ 3. On an ELF system, if the '-rpath' and 'rpath-link' options
+ were not used, search the contents of the environment variable
+ 'LD_RUN_PATH'. It is for the native linker only.
+ 4. On SunOS, if the '-rpath' option was not used, search any
+ directories specified using '-L' options.
+ 5. For a native linker, the contents of the environment variable
+ 'LD_LIBRARY_PATH'.
+ 6. For a native ELF linker, the directories in 'DT_RUNPATH' or
+ 'DT_RPATH' of a shared library are searched for shared
+ libraries needed by it. The 'DT_RPATH' entries are ignored if
+ 'DT_RUNPATH' entries exist.
+ 7. The default directories, normally '/lib' and '/usr/lib'.
+ 8. For a native linker on an ELF system, if the file
+ '/etc/ld.so.conf' exists, the list of directories found in
+ that file.
+
+ If the required shared library is not found, the linker will issue
+ a warning and continue with the link.
+
+'-shared'
+'-Bshareable'
+ 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 '-e' option is not used and there
+ are undefined symbols in the link.
+
+'--sort-common'
+ This option tells '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 byte, then all the four byte,
+ and then everything else. This is to prevent gaps between symbols
+ due to alignment constraints.
+
+'--sort-section name'
+ This option will apply 'SORT_BY_NAME' to all wildcard section
+ patterns in the linker script.
+
+'--sort-section alignment'
+ This option will apply 'SORT_BY_ALIGNMENT' to all wildcard section
+ patterns in the linker script.
+
+'--split-by-file [SIZE]'
+ Similar to '--split-by-reloc' but creates a new output section for
+ each input file when SIZE is reached. SIZE defaults to a size of 1
+ if not given.
+
+'--split-by-reloc [COUNT]'
+ Tries to creates extra sections in the output file so that no
+ single output section in the file contains more than COUNT
+ relocations. 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
+ COUNT relocations one output section will contain that many
+ relocations. COUNT defaults to a value of 32768.
+
+'--stats'
+ Compute and display statistics about the operation of the linker,
+ such as execution time and memory usage.
+
+'--sysroot=DIRECTORY'
+ Use DIRECTORY as the location of the sysroot, overriding the
+ configure-time default. This option is only supported by linkers
+ that were configured using '--with-sysroot'.
+
+'--traditional-format'
+ For some targets, the output of 'ld' is different in some ways from
+ the output of some existing linker. This switch requests 'ld' to
+ use the traditional format instead.
+
+ For example, on SunOS, '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 'dbx' program can not read the resulting program ('gdb'
+ has no trouble). The '--traditional-format' switch tells 'ld' to
+ not combine duplicate entries.
+
+'--section-start SECTIONNAME=ORG'
+ Locate a section in the output file at the absolute address given
+ by ORG. You may use this option as many times as necessary to
+ locate multiple sections in the command line. ORG must be a single
+ hexadecimal integer; for compatibility with other linkers, you may
+ omit the leading '0x' usually associated with hexadecimal values.
+ _Note:_ there should be no white space between SECTIONNAME, the
+ equals sign ("<=>"), and ORG.
+
+'-Tbss ORG'
+'-Tdata ORG'
+'-Ttext ORG'
+ Same as -section-start, with '.bss', '.data' or '.text' as the
+ SECTIONNAME.
+
+'--unresolved-symbols=METHOD'
+ Determine how to handle unresolved symbols. There are four
+ possible values for 'method':
+
+ 'ignore-all'
+ Do not report any unresolved symbols.
+
+ 'report-all'
+ Report all unresolved symbols. This is the default.
+
+ 'ignore-in-object-files'
+ Report unresolved symbols that are contained in shared
+ libraries, but ignore them if they come from regular object
+ files.
+
+ 'ignore-in-shared-libs'
+ Report unresolved symbols that come from regular object files,
+ but ignore them if they come from shared libraries. This can
+ be useful when creating a dynamic binary and it is known that
+ all the shared libraries that it should be referencing are
+ included on the linker's command line.
+
+ The behaviour for shared libraries on their own can also be
+ controlled by the '--[no-]allow-shlib-undefined' option.
+
+ Normally the linker will generate an error message for each
+ reported unresolved symbol but the option
+ '--warn-unresolved-symbols' can change this to a warning.
+
+'--dll-verbose'
+'--verbose'
+ Display the version number for 'ld' and list the linker emulations
+ supported. Display which input files can and cannot be opened.
+ Display the linker script being used by the linker.
+
+'--version-script=VERSION-SCRIPTFILE'
+ Specify the name of a version script to the linker. This is
+ typically used when creating shared libraries to specify additional
+ information about the version hierarchy for the library being
+ created. This option is only meaningful on ELF platforms which
+ support shared libraries. *Note VERSION::.
+
+'--warn-common'
+ Warn when a common symbol is combined with another common symbol or
+ with a symbol definition. Unix linkers allow this somewhat sloppy
+ practise, but linkers on some other operating systems do not. This
+ option allows you to find potential problems from combining global
+ symbols. Unfortunately, some C libraries use this practise, so you
+ may get some warnings about symbols in the libraries as well as in
+ your programs.
+
+ There are three kinds of global symbols, illustrated here by C
+ examples:
+
+ 'int i = 1;'
+ A definition, which goes in the initialized data section of
+ the output file.
+
+ 'extern int i;'
+ An undefined reference, which does not allocate space. There
+ must be either a definition or a common symbol for the
+ variable somewhere.
+
+ 'int i;'
+ A common symbol. If there are only (one or more) common
+ symbols for a variable, it goes in the uninitialized data area
+ of the output file. The linker merges multiple common symbols
+ for the same variable into a single symbol. If they are of
+ different sizes, it picks the largest size. The linker turns
+ a common symbol into a declaration, if there is a definition
+ of the same variable.
+
+ The '--warn-common' option can produce five kinds of warnings.
+ Each warning consists of a pair of lines: the first describes the
+ symbol just encountered, and the second describes the previous
+ symbol encountered with the same name. One or both of the two
+ symbols will be a common symbol.
+
+ 1. Turning a common symbol into a reference, because there is
+ already a definition for the symbol.
+ FILE(SECTION): warning: common of `SYMBOL'
+ overridden by definition
+ FILE(SECTION): warning: defined here
+
+ 2. Turning a common symbol into a reference, because a later
+ definition for the symbol is encountered. This is the same as
+ the previous case, except that the symbols are encountered in
+ a different order.
+ FILE(SECTION): warning: definition of `SYMBOL'
+ overriding common
+ FILE(SECTION): warning: common is here
+
+ 3. Merging a common symbol with a previous same-sized common
+ symbol.
+ FILE(SECTION): warning: multiple common
+ of `SYMBOL'
+ FILE(SECTION): warning: previous common is here
+
+ 4. Merging a common symbol with a previous larger common symbol.
+ FILE(SECTION): warning: common of `SYMBOL'
+ overridden by larger common
+ FILE(SECTION): warning: larger common is here
+
+ 5. Merging a common symbol with a previous smaller common symbol.
+ This is the same as the previous case, except that the symbols
+ are encountered in a different order.
+ FILE(SECTION): warning: common of `SYMBOL'
+ overriding smaller common
+ FILE(SECTION): warning: smaller common is here
+
+'--warn-constructors'
+ Warn if any global constructors are used. This is only useful for
+ a few object file formats. For formats like COFF or ELF, the
+ linker can not detect the use of global constructors.
+
+'--warn-multiple-gp'
+ Warn if multiple global pointer values are required in the output
+ file. This is only meaningful for certain processors, such as the
+ Alpha. Specifically, some processors put large-valued constants in
+ a special section. A special register (the global pointer) points
+ into the middle of this section, so that constants can be loaded
+ efficiently via a base-register relative addressing mode. Since
+ the offset in base-register relative mode is fixed and relatively
+ small (e.g., 16 bits), this limits the maximum size of the constant
+ pool. Thus, in large programs, it is often necessary to use
+ multiple global pointer values in order to be able to address all
+ possible constants. This option causes a warning to be issued
+ whenever this case occurs.
+
+'--warn-once'
+ Only warn once for each undefined symbol, rather than once per
+ module which refers to it.
+
+'--warn-section-align'
+ Warn if the address of an output section is changed because of
+ alignment. Typically, the alignment will be set by an input
+ section. The address will only be changed if it not explicitly
+ specified; that is, if the 'SECTIONS' command does not specify a
+ start address for the section (*note SECTIONS::).
+
+'--warn-shared-textrel'
+ Warn if the linker adds a DT_TEXTREL to a shared object.
+
+'--warn-unresolved-symbols'
+ If the linker is going to report an unresolved symbol (see the
+ option '--unresolved-symbols') it will normally generate an error.
+ This option makes it generate a warning instead.
+
+'--error-unresolved-symbols'
+ This restores the linker's default behaviour of generating errors
+ when it is reporting unresolved symbols.
+
+'--whole-archive'
+ For each archive mentioned on the command line after the
+ '--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 '-Wl,-whole-archive'.
+ Second, don't forget to use '-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.
+
+'--wrap SYMBOL'
+ Use a wrapper function for SYMBOL. Any undefined reference to
+ SYMBOL will be resolved to '__wrap_SYMBOL'. Any undefined
+ reference to '__real_SYMBOL' will be resolved to SYMBOL.
+
+ This can be used to provide a wrapper for a system function. The
+ wrapper function should be called '__wrap_SYMBOL'. If it wishes to
+ call the system function, it should call '__real_SYMBOL'.
+
+ Here is a trivial example:
+
+ void *
+ __wrap_malloc (size_t c)
+ {
+ printf ("malloc called with %zu\n", c);
+ return __real_malloc (c);
+ }
+
+ If you link other code with this file using '--wrap malloc', then
+ all calls to 'malloc' will call the function '__wrap_malloc'
+ instead. The call to '__real_malloc' in '__wrap_malloc' will call
+ the real 'malloc' function.
+
+ You may wish to provide a '__real_malloc' function as well, so that
+ links without the '--wrap' option will succeed. If you do this,
+ you should not put the definition of '__real_malloc' in the same
+ file as '__wrap_malloc'; if you do, the assembler may resolve the
+ call before the linker has a chance to wrap it to 'malloc'.
+
+'--eh-frame-hdr'
+ Request creation of '.eh_frame_hdr' section and ELF
+ 'PT_GNU_EH_FRAME' segment header.
+
+'--enable-new-dtags'
+'--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
+ '--enable-new-dtags', the dynamic tags will be created as needed.
+ If you specify '--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.
+
+'--hash-size=NUMBER'
+ Set the default size of the linker's hash tables to a prime number
+ close to NUMBER. Increasing this value can reduce the length of
+ time it takes the linker to perform its tasks, at the expense of
+ increasing the linker's memory requirements. Similarly reducing
+ this value can reduce the memory requirements at the expense of
+ speed.
+
+'--hash-style=STYLE'
+ Set the type of linker's hash table(s). STYLE can be either 'sysv'
+ for classic ELF '.hash' section, 'gnu' for new style GNU
+ '.gnu.hash' section or 'both' for both the classic ELF '.hash' and
+ new style GNU '.gnu.hash' hash tables. The default is 'sysv'.
+
+'--reduce-memory-overheads'
+ This option reduces memory requirements at ld runtime, at the
+ expense of linking speed. This was introduced to select the old
+ O(n^2) algorithm for link map file generation, rather than the new
+ O(n) algorithm which uses about 40% more memory for symbol storage.
+
+ Another effect of the switch is to set the default hash table size
+ to 1021, which again saves memory at the cost of lengthening the
+ linker's run time. This is not done however if the '--hash-size'
+ switch has been used.
+
+ The '--reduce-memory-overheads' switch may be also be used to
+ enable other tradeoffs in future versions of the linker.
+
+2.1.1 Options Specific to i386 PE Targets
+-----------------------------------------
+
+The i386 PE linker supports the '-shared' option, which causes the
+output to be a dynamically linked library (DLL) instead of a normal
+executable. You should name the output '*.dll' when you use this
+option. In addition, the linker fully supports the standard '*.def'
+files, which may be specified on the linker command line like an object
+file (in fact, it should precede archives it exports symbols from, to
+ensure that they get linked in, just like a normal object file).
+
+ In addition to the options common to all targets, the i386 PE linker
+support additional command line options that are specific to the i386 PE
+target. Options that take values may be separated from their values by
+either a space or an equals sign.
+
+'--add-stdcall-alias'
+ If given, symbols with a stdcall suffix (@NN) will be exported
+ as-is and also with the suffix stripped. [This option is specific
+ to the i386 PE targeted port of the linker]
+
+'--base-file FILE'
+ Use FILE as the name of a file in which to save the base addresses
+ of all the relocations needed for generating DLLs with 'dlltool'.
+ [This is an i386 PE specific option]
+
+'--dll'
+ Create a DLL instead of a regular executable. You may also use
+ '-shared' or specify a 'LIBRARY' in a given '.def' file. [This
+ option is specific to the i386 PE targeted port of the linker]
+
+'--enable-stdcall-fixup'
+'--disable-stdcall-fixup'
+ If the link finds a symbol that it cannot resolve, it will attempt
+ to do "fuzzy linking" by looking for another defined symbol that
+ differs only in the format of the symbol name (cdecl vs stdcall)
+ and will resolve that symbol by linking to the match. For example,
+ the undefined symbol '_foo' might be linked to the function
+ '_foo@12', or the undefined symbol '_bar@16' might be linked to the
+ function '_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 '--enable-stdcall-fixup', this feature
+ is fully enabled and warnings are not printed. If you specify
+ '--disable-stdcall-fixup', this feature is disabled and such
+ mismatches are considered to be errors. [This option is specific
+ to the i386 PE targeted port of the linker]
+
+'--export-all-symbols'
+ If given, all global symbols in the objects used to build a DLL
+ will be exported by the DLL. Note that this is the default if there
+ otherwise wouldn't be any exported symbols. When symbols are
+ 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 'DllMain@12',
+ 'DllEntryPoint@0', 'DllMainCRTStartup@12', and '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 '_head_' or ending
+ with '_iname'. In addition, no symbols from 'libgcc', 'libstd++',
+ 'libmingw32', or 'crtX.o' will be exported. Symbols whose names
+ begin with '__rtti_' or '__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: '_cygwin_dll_entry@12',
+ '_cygwin_crt0_common@8', '_cygwin_noncygwin_dll_entry@12',
+ '_fmode', '_impure_ptr', 'cygwin_attach_dll', 'cygwin_premain0',
+ 'cygwin_premain1', 'cygwin_premain2', 'cygwin_premain3', and
+ 'environ'. [This option is specific to the i386 PE targeted port
+ of the linker]
+
+'--exclude-symbols SYMBOL,SYMBOL,...'
+ Specifies a list of symbols which should not be automatically
+ exported. The symbol names may be delimited by commas or colons.
+ [This option is specific to the i386 PE targeted port of the
+ linker]
+
+'--file-alignment'
+ Specify the file alignment. Sections in the file will always begin
+ at file offsets which are multiples of this number. This defaults
+ to 512. [This option is specific to the i386 PE targeted port of
+ the linker]
+
+'--heap RESERVE'
+'--heap RESERVE,COMMIT'
+ Specify the amount of memory to reserve (and optionally commit) to
+ be used as heap for this program. The default is 1Mb reserved, 4K
+ committed. [This option is specific to the i386 PE targeted port
+ of the linker]
+
+'--image-base VALUE'
+ Use VALUE as the base address of your program or dll. This is the
+ lowest memory location that will be used when your program or dll
+ is loaded. To reduce the need to relocate and improve performance
+ of your dlls, each should have a unique base address and not
+ overlap any other dlls. The default is 0x400000 for executables,
+ and 0x10000000 for dlls. [This option is specific to the i386 PE
+ targeted port of the linker]
+
+'--kill-at'
+ If given, the stdcall suffixes (@NN) will be stripped from symbols
+ before they are exported. [This option is specific to the i386 PE
+ targeted port of the linker]
+
+'--large-address-aware'
+ If given, the appropriate bit in the "Characteristics" field of the
+ COFF header is set to indicate that this executable supports
+ virtual addresses greater than 2 gigabytes. This should be used in
+ conjunction with the /3GB or /USERVA=VALUE megabytes switch in the
+ "[operating systems]" section of the BOOT.INI. Otherwise, this bit
+ has no effect. [This option is specific to PE targeted ports of
+ the linker]
+
+'--major-image-version VALUE'
+ Sets the major number of the "image version". Defaults to 1.
+ [This option is specific to the i386 PE targeted port of the
+ linker]
+
+'--major-os-version VALUE'
+ Sets the major number of the "os version". Defaults to 4. [This
+ option is specific to the i386 PE targeted port of the linker]
+
+'--major-subsystem-version VALUE'
+ Sets the major number of the "subsystem version". Defaults to 4.
+ [This option is specific to the i386 PE targeted port of the
+ linker]
+
+'--minor-image-version VALUE'
+ Sets the minor number of the "image version". Defaults to 0.
+ [This option is specific to the i386 PE targeted port of the
+ linker]
+
+'--minor-os-version VALUE'
+ Sets the minor number of the "os version". Defaults to 0. [This
+ option is specific to the i386 PE targeted port of the linker]
+
+'--minor-subsystem-version VALUE'
+ Sets the minor number of the "subsystem version". Defaults to 0.
+ [This option is specific to the i386 PE targeted port of the
+ linker]
+
+'--output-def FILE'
+ The linker will create the file FILE which will contain a DEF file
+ corresponding to the DLL the linker is generating. This DEF file
+ (which should be called '*.def') may be used to create an import
+ library with 'dlltool' or may be used as a reference to
+ automatically or implicitly exported symbols. [This option is
+ specific to the i386 PE targeted port of the linker]
+
+'--out-implib FILE'
+ The linker will create the file FILE which will contain an import
+ lib corresponding to the DLL the linker is generating. This import
+ lib (which should be called '*.dll.a' or '*.a' may be used to link
+ clients against the generated DLL; this behaviour makes it possible
+ to skip a separate 'dlltool' import library creation step. [This
+ option is specific to the i386 PE targeted port of the linker]
+
+'--enable-auto-image-base'
+ Automatically choose the image base for DLLs, unless one is
+ specified using the '--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. [This option is specific to the i386 PE
+ targeted port of the linker]
+
+'--disable-auto-image-base'
+ Do not automatically generate a unique image base. If there is no
+ user-specified image base ('--image-base') then use the platform
+ default. [This option is specific to the i386 PE targeted port of
+ the linker]
+
+'--dll-search-prefix STRING'
+ When linking dynamically to a dll without an import library, search
+ for '<string><basename>.dll' in preference to 'lib<basename>.dll'.
+ This behaviour allows easy distinction between DLLs built for the
+ various "subplatforms": native, cygwin, uwin, pw, etc. For
+ instance, cygwin DLLs typically use '--dll-search-prefix=cyg'.
+ [This option is specific to the i386 PE targeted port of the
+ linker]
+
+'--enable-auto-import'
+ Do sophisticated linking of '_symbol' to '__imp__symbol' for DATA
+ imports from DLLs, and create the necessary thunking symbols when
+ building the import libraries with those DATA exports. Note: Use
+ of the 'auto-import' extension will cause the text section of the
+ image file to be made writable. This does not conform to the
+ PE-COFF format specification published by Microsoft.
+
+ Using 'auto-import' 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 '--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 environment
+ 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:
+
+ extern type extern_array[];
+ extern_array[1] -->
+ { volatile type *t=extern_array; t[1] }
+
+ or
+
+ extern type extern_array[];
+ extern_array[1] -->
+ { volatile int t=1; extern_array[t] }
+
+ For structs (and most other multiword data types) the only option
+ is to make the struct itself (or the long long, or the ...)
+ variable:
+
+ extern struct s extern_struct;
+ extern_struct.field -->
+ { volatile struct s *t=&extern_struct; t->field }
+
+ or
+
+ extern long long extern_ll;
+ extern_ll -->
+ { volatile long long * local_ll=&extern_ll; *local_ll }
+
+ A third method of dealing with this difficulty is to abandon
+ 'auto-import' for the offending symbol and mark it with
+ '__declspec(dllimport)'. However, in practise 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:
+ --foo.h
+ extern int arr[];
+ --foo.c
+ #include "foo.h"
+ void main(int argc, char **argv){
+ printf("%d\n",arr[1]);
+ }
+
+ Solution 1:
+ --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]);
+ }
+
+ Solution 2:
+ --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]);
+ }
+
+ 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). [This option is specific to the i386 PE targeted port
+ of the linker]
+
+'--disable-auto-import'
+ Do not attempt to do sophisticated linking of '_symbol' to
+ '__imp__symbol' for DATA imports from DLLs. [This option is
+ specific to the i386 PE targeted port of the linker]
+
+'--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. [This option is specific to the i386 PE
+ targeted port of the linker]
+
+'--disable-runtime-pseudo-reloc'
+ Do not create pseudo relocations for non-zero offset DATA imports
+ from DLLs. This is the default. [This option is specific to the
+ i386 PE targeted port of the linker]
+
+'--enable-extra-pe-debug'
+ Show additional debug info related to auto-import symbol thunking.
+ [This option is specific to the i386 PE targeted port of the
+ linker]
+
+'--section-alignment'
+ Sets the section alignment. Sections in memory will always begin
+ at addresses which are a multiple of this number. Defaults to
+ 0x1000. [This option is specific to the i386 PE targeted port of
+ the linker]
+
+'--stack RESERVE'
+'--stack RESERVE,COMMIT'
+ Specify the amount of memory to reserve (and optionally commit) to
+ be used as stack for this program. The default is 2Mb reserved, 4K
+ committed. [This option is specific to the i386 PE targeted port
+ of the linker]
+
+'--subsystem WHICH'
+'--subsystem WHICH:MAJOR'
+'--subsystem WHICH:MAJOR.MINOR'
+ Specifies the subsystem under which your program will execute. The
+ legal values for WHICH are 'native', 'windows', 'console', 'posix',
+ and 'xbox'. You may optionally set the subsystem version also.
+ Numeric values are also accepted for WHICH. [This option is
+ specific to the i386 PE targeted port of the linker]
+
+2.1.2 Options specific to Motorola 68HC11 and 68HC12 targets
+------------------------------------------------------------
+
+The 68HC11 and 68HC12 linkers support specific options to control the
+memory bank switching mapping and trampoline code generation.
+
+'--no-trampoline'
+ This option disables the generation of trampoline. By default a
+ trampoline is generated for each far function which is called using
+ a 'jsr' instruction (this happens when a pointer to a far function
+ is taken).
+
+'--bank-window NAME'
+ This option indicates to the linker the name of the memory region
+ in the 'MEMORY' specification that describes the memory bank
+ window. The definition of such region is then used by the linker
+ to compute paging and addresses within the memory window.
+
+2.2 Environment Variables
+=========================
+
+You can change the behaviour of 'ld' with the environment variables
+'GNUTARGET', 'LDEMULATION' and 'COLLECT_NO_DEMANGLE'.
+
+ 'GNUTARGET' determines the input-file object format if you don't use
+'-b' (or its synonym '--format'). Its value should be one of the BFD
+names for an input format (*note BFD::). If there is no 'GNUTARGET' in
+the environment, 'ld' uses the natural format of the target. If
+'GNUTARGET' is set to 'default' then BFD attempts to discover the input
+format by examining binary input files; this method often succeeds, but
+there are potential ambiguities, since there is no method of ensuring
+that the magic number used to specify object-file formats is unique.
+However, the configuration procedure for BFD on each system places the
+conventional format for that system first in the search-list, so
+ambiguities are resolved in favor of convention.
+
+ 'LDEMULATION' determines the default emulation if you don't use the
+'-m' option. The emulation can affect various aspects of linker
+behaviour, particularly the default linker script. You can list the
+available emulations with the '--verbose' or '-V' options. If the '-m'
+option is not used, and the 'LDEMULATION' environment variable is not
+defined, the default emulation depends upon how the linker was
+configured.
+
+ Normally, the linker will default to demangling symbols. However, if
+'COLLECT_NO_DEMANGLE' is set in the environment, then it will default to
+not demangling symbols. This environment variable is used in a similar
+fashion by the 'gcc' linker wrapper program. The default may be
+overridden by the '--demangle' and '--no-demangle' options.
+
+3 Linker Scripts
+****************
+
+Every link is controlled by a "linker script". This script is written
+in the linker command language.
+
+ The main purpose of the linker script is to describe how the sections
+in the input files should be mapped into the output file, and to control
+the memory layout of the output file. Most linker scripts do nothing
+more than this. However, when necessary, the linker script can also
+direct the linker to perform many other operations, using the commands
+described below.
+
+ The linker always uses a linker script. If you do not supply one
+yourself, the linker will use a default script that is compiled into the
+linker executable. You can use the '--verbose' command line option to
+display the default linker script. Certain command line options, such
+as '-r' or '-N', will affect the default linker script.
+
+ You may supply your own linker script by using the '-T' command line
+option. When you do this, your linker script will replace the default
+linker script.
+
+ You may also use linker scripts implicitly by naming them as input
+files to the linker, as though they were files to be linked. *Note
+Implicit Linker Scripts::.
+
+3.1 Basic Linker Script Concepts
+================================
+
+We need to define some basic concepts and vocabulary in order to
+describe the linker script language.
+
+ The linker combines input files into a single output file. The
+output file and each input file are in a special data format known as an
+"object file format". Each file is called an "object file". The output
+file is often called an "executable", but for our purposes we will also
+call it an object file. Each object file has, among other things, a
+list of "sections". We sometimes refer to a section in an input file as
+an "input section"; similarly, a section in the output file is an
+"output section".
+
+ Each section in an object file has a name and a size. Most sections
+also have an associated block of data, known as the "section contents".
+A section may be marked as "loadable", which mean that the contents
+should be loaded into memory when the output file is run. A section
+with no contents may be "allocatable", which means that an area in
+memory should be set aside, but nothing in particular should be loaded
+there (in some cases this memory must be zeroed out). A section which
+is neither loadable nor allocatable typically contains some sort of
+debugging information.
+
+ Every loadable or allocatable output section has two addresses. The
+first is the "VMA", or virtual memory address. This is the address the
+section will have when the output file is run. The second is the "LMA",
+or load memory address. This is the address at which the section will
+be loaded. In most cases the two addresses will be the same. An
+example of when they might be different is when a data section is loaded
+into ROM, and then copied into RAM when the program starts up (this
+technique is often used to initialize global variables in a ROM based
+system). In this case the ROM address would be the LMA, and the RAM
+address would be the VMA.
+
+ You can see the sections in an object file by using the 'objdump'
+program with the '-h' option.
+
+ Every object file also has a list of "symbols", known as the "symbol
+table". A symbol may be defined or undefined. Each symbol has a name,
+and each defined symbol has an address, among other information. If you
+compile a C or C++ program into an object file, you will get a defined
+symbol for every defined function and global or static variable. Every
+undefined function or global variable which is referenced in the input
+file will become an undefined symbol.
+
+ You can see the symbols in an object file by using the 'nm' program,
+or by using the 'objdump' program with the '-t' option.
+
+3.2 Linker Script Format
+========================
+
+Linker scripts are text files.
+
+ You write a linker script as a series of commands. Each command is
+either a keyword, possibly followed by arguments, or an assignment to a
+symbol. You may separate commands using semicolons. Whitespace is
+generally ignored.
+
+ Strings such as file or format names can normally be entered
+directly. If the file name contains a character such as a comma which
+would otherwise serve to separate file names, you may put the file name
+in double quotes. There is no way to use a double quote character in a
+file name.
+
+ You may include comments in linker scripts just as in C, delimited by
+'/*' and '*/'. As in C, comments are syntactically equivalent to
+whitespace.
+
+3.3 Simple Linker Script Example
+================================
+
+Many linker scripts are fairly simple.
+
+ The simplest possible linker script has just one command: 'SECTIONS'.
+You use the 'SECTIONS' command to describe the memory layout of the
+output file.
+
+ The 'SECTIONS' command is a powerful command. Here we will describe
+a simple use of it. Let's assume your program consists only of code,
+initialized data, and uninitialized data. These will be in the '.text',
+'.data', and '.bss' sections, respectively. Let's assume further that
+these are the only sections which appear in your input files.
+
+ For this example, let's say that the code should be loaded at address
+0x10000, and that the data should start at address 0x8000000. Here is a
+linker script which will do that:
+ SECTIONS
+ {
+ . = 0x10000;
+ .text : { *(.text) }
+ . = 0x8000000;
+ .data : { *(.data) }
+ .bss : { *(.bss) }
+ }
+
+ You write the 'SECTIONS' command as the keyword 'SECTIONS', followed
+by a series of symbol assignments and output section descriptions
+enclosed in curly braces.
+
+ The first line inside the 'SECTIONS' command of the above example
+sets the value of the special symbol '.', 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. At the start of the 'SECTIONS'
+command, the location counter has the value '0'.
+
+ The second line defines an output section, '.text'. The colon is
+required syntax which may be ignored for now. Within the curly braces
+after the output section name, you list the names of the input sections
+which should be placed into this output section. The '*' is a wildcard
+which matches any file name. The expression '*(.text)' means all
+'.text' input sections in all input files.
+
+ Since the location counter is '0x10000' when the output section
+'.text' is defined, the linker will set the address of the '.text'
+section in the output file to be '0x10000'.
+
+ The remaining lines define the '.data' and '.bss' sections in the
+output file. The linker will place the '.data' output section at
+address '0x8000000'. After the linker places the '.data' output
+section, the value of the location counter will be '0x8000000' plus the
+size of the '.data' output section. The effect is that the linker will
+place the '.bss' output section immediately after the '.data' output
+section in memory.
+
+ The linker will ensure that each output section has the required
+alignment, by increasing the location counter if necessary. In this
+example, the specified addresses for the '.text' and '.data' sections
+will probably satisfy any alignment constraints, but the linker may have
+to create a small gap between the '.data' and '.bss' sections.
+
+ That's it! That's a simple and complete linker script.
+
+3.4 Simple Linker Script Commands
+=================================
+
+In this section we describe the simple linker script commands.
+
+3.4.1 Setting the Entry Point
+-----------------------------
+
+The first instruction to execute in a program is called the "entry
+point". You can use the 'ENTRY' linker script command to set the entry
+point. The argument is a symbol name:
+ ENTRY(SYMBOL)
+
+ There are several ways to set the entry point. The linker will set
+the entry point by trying each of the following methods in order, and
+stopping when one of them succeeds:
+ * the '-e' ENTRY command-line option;
+ * the 'ENTRY(SYMBOL)' command in a linker script;
+ * the value of the symbol 'start', if defined;
+ * the address of the first byte of the '.text' section, if present;
+ * The address '0'.
+
+3.4.2 Commands Dealing with Files
+---------------------------------
+
+Several linker script commands deal with files.
+
+'INCLUDE FILENAME'
+ Include the linker script FILENAME at this point. The file will be
+ searched for in the current directory, and in any directory
+ specified with the '-L' option. You can nest calls to 'INCLUDE' up
+ to 10 levels deep.
+
+'INPUT(FILE, FILE, ...)'
+'INPUT(FILE FILE ...)'
+ The 'INPUT' command directs the linker to include the named files
+ in the link, as though they were named on the command line.
+
+ For example, if you always want to include 'subr.o' any time you do
+ a link, but you can't be bothered to put it on every link command
+ line, then you can put 'INPUT (subr.o)' in your linker script.
+
+ In fact, if you like, you can list all of your input files in the
+ linker script, and then invoke the linker with nothing but a '-T'
+ option.
+
+ In case a "sysroot prefix" is configured, and the filename starts
+ with the '/' character, and the script being processed was located
+ inside the "sysroot prefix", the filename will be looked for in the
+ "sysroot prefix". Otherwise, the linker will try to open the file
+ in the current directory. If it is not found, the linker will
+ search through the archive library search path. See the
+ description of '-L' in *note Command Line Options: Options.
+
+ If you use 'INPUT (-lFILE)', 'ld' will transform the name to
+ 'libFILE.a', as with the command line argument '-l'.
+
+ When you use the 'INPUT' command in an implicit linker script, the
+ files will be included in the link at the point at which the linker
+ script file is included. This can affect archive searching.
+
+'GROUP(FILE, FILE, ...)'
+'GROUP(FILE FILE ...)'
+ The 'GROUP' command is like 'INPUT', except that the named files
+ should all be archives, and they are searched repeatedly until no
+ new undefined references are created. See the description of '-('
+ in *note Command Line Options: Options.
+
+'AS_NEEDED(FILE, FILE, ...)'
+'AS_NEEDED(FILE FILE ...)'
+ This construct can appear only inside of the 'INPUT' or 'GROUP'
+ commands, among other filenames. The files listed will be handled
+ as if they appear directly in the 'INPUT' or 'GROUP' commands, with
+ the exception of ELF shared libraries, that will be added only when
+ they are actually needed. This construct essentially enables
+ '--as-needed' option for all the files listed inside of it and
+ restores previous '--as-needed' resp. '--no-as-needed' setting
+ afterwards.
+
+'OUTPUT(FILENAME)'
+ The 'OUTPUT' command names the output file. Using
+ 'OUTPUT(FILENAME)' in the linker script is exactly like using '-o
+ FILENAME' on the command line (*note Command Line Options:
+ Options.). If both are used, the command line option takes
+ precedence.
+
+ You can use the 'OUTPUT' command to define a default name for the
+ output file other than the usual default of 'a.out'.
+
+'SEARCH_DIR(PATH)'
+ The 'SEARCH_DIR' command adds PATH to the list of paths where 'ld'
+ looks for archive libraries. Using 'SEARCH_DIR(PATH)' is exactly
+ like using '-L PATH' on the command line (*note Command Line
+ Options: Options.). If both are used, then the linker will search
+ both paths. Paths specified using the command line option are
+ searched first.
+
+'STARTUP(FILENAME)'
+ The 'STARTUP' command is just like the 'INPUT' command, except that
+ FILENAME will become the first input file to be linked, as though
+ it were specified first on the command line. This may be useful
+ when using a system in which the entry point is always the start of
+ the first file.
+
+3.4.3 Commands Dealing with Object File Formats
+-----------------------------------------------
+
+A couple of linker script commands deal with object file formats.
+
+'OUTPUT_FORMAT(BFDNAME)'
+'OUTPUT_FORMAT(DEFAULT, BIG, LITTLE)'
+ The 'OUTPUT_FORMAT' command names the BFD format to use for the
+ output file (*note BFD::). Using 'OUTPUT_FORMAT(BFDNAME)' is
+ exactly like using '--oformat BFDNAME' on the command line (*note
+ Command Line Options: Options.). If both are used, the command
+ line option takes precedence.
+
+ You can use 'OUTPUT_FORMAT' with three arguments to use different
+ formats based on the '-EB' and '-EL' command line options. This
+ permits the linker script to set the output format based on the
+ desired endianness.
+
+ If neither '-EB' nor '-EL' are used, then the output format will be
+ the first argument, DEFAULT. If '-EB' is used, the output format
+ will be the second argument, BIG. If '-EL' is used, the output
+ format will be the third argument, LITTLE.
+
+ For example, the default linker script for the MIPS ELF target uses
+ this command:
+ OUTPUT_FORMAT(elf32-bigmips, elf32-bigmips, elf32-littlemips)
+ This says that the default format for the output file is
+ 'elf32-bigmips', but if the user uses the '-EL' command line
+ option, the output file will be created in the 'elf32-littlemips'
+ format.
+
+'TARGET(BFDNAME)'
+ The 'TARGET' command names the BFD format to use when reading input
+ files. It affects subsequent 'INPUT' and 'GROUP' commands. This
+ command is like using '-b BFDNAME' on the command line (*note
+ Command Line Options: Options.). If the 'TARGET' command is used
+ but 'OUTPUT_FORMAT' is not, then the last 'TARGET' command is also
+ used to set the format for the output file. *Note BFD::.
+
+3.4.4 Other Linker Script Commands
+----------------------------------
+
+There are a few other linker scripts commands.
+
+'ASSERT(EXP, MESSAGE)'
+ Ensure that EXP is non-zero. If it is zero, then exit the linker
+ with an error code, and print MESSAGE.
+
+'EXTERN(SYMBOL SYMBOL ...)'
+ Force SYMBOL to be entered in the output file as an undefined
+ symbol. Doing this may, for example, trigger linking of additional
+ modules from standard libraries. You may list several SYMBOLs for
+ each 'EXTERN', and you may use 'EXTERN' multiple times. This
+ command has the same effect as the '-u' command-line option.
+
+'FORCE_COMMON_ALLOCATION'
+ This command has the same effect as the '-d' command-line option:
+ to make 'ld' assign space to common symbols even if a relocatable
+ output file is specified ('-r').
+
+'INHIBIT_COMMON_ALLOCATION'
+ This command has the same effect as the '--no-define-common'
+ command-line option: to make 'ld' omit the assignment of addresses
+ to common symbols even for a non-relocatable output file.
+
+'NOCROSSREFS(SECTION SECTION ...)'
+ This command may be used to tell 'ld' to issue an error about any
+ references among certain output sections.
+
+ In certain types of programs, particularly on embedded systems when
+ using overlays, when one section is loaded into memory, another
+ section will not be. Any direct references between the two
+ sections would be errors. For example, it would be an error if
+ code in one section called a function defined in the other section.
+
+ The 'NOCROSSREFS' command takes a list of output section names. If
+ 'ld' detects any cross references between the sections, it reports
+ an error and returns a non-zero exit status. Note that the
+ 'NOCROSSREFS' command uses output section names, not input section
+ names.
+
+'OUTPUT_ARCH(BFDARCH)'
+ Specify a particular output machine architecture. The argument is
+ one of the names used by the BFD library (*note BFD::). You can
+ see the architecture of an object file by using the 'objdump'
+ program with the '-f' option.
+
+3.5 Assigning Values to Symbols
+===============================
+
+You may assign a value to a symbol in a linker script. This will define
+the symbol and place it into the symbol table with a global scope.
+
+3.5.1 Simple Assignments
+------------------------
+
+You may assign to a symbol using any of the C assignment operators:
+
+'SYMBOL = EXPRESSION ;'
+'SYMBOL += EXPRESSION ;'
+'SYMBOL -= EXPRESSION ;'
+'SYMBOL *= EXPRESSION ;'
+'SYMBOL /= EXPRESSION ;'
+'SYMBOL <<= EXPRESSION ;'
+'SYMBOL >>= EXPRESSION ;'
+'SYMBOL &= EXPRESSION ;'
+'SYMBOL |= EXPRESSION ;'
+
+ The first case will define SYMBOL to the value of EXPRESSION. In the
+other cases, SYMBOL must already be defined, and the value will be
+adjusted accordingly.
+
+ The special symbol name '.' indicates the location counter. You may
+only use this within a 'SECTIONS' command. *Note Location Counter::.
+
+ The semicolon after EXPRESSION is required.
+
+ Expressions are defined below; see *note Expressions::.
+
+ You may write symbol assignments as commands in their own right, or
+as statements within a 'SECTIONS' command, or as part of an output
+section description in a 'SECTIONS' command.
+
+ The section of the symbol will be set from the section of the
+expression; for more information, see *note Expression Section::.
+
+ Here is an example showing the three different places that symbol
+assignments may be used:
+
+ floating_point = 0;
+ SECTIONS
+ {
+ .text :
+ {
+ *(.text)
+ _etext = .;
+ }
+ _bdata = (. + 3) & ~ 3;
+ .data : { *(.data) }
+ }
+In this example, the symbol 'floating_point' will be defined as zero.
+The symbol '_etext' will be defined as the address following the last
+'.text' input section. The symbol '_bdata' will be defined as the
+address following the '.text' output section aligned upward to a 4 byte
+boundary.
+
+3.5.2 PROVIDE
+-------------
+
+In some cases, it is desirable for a linker script to define a symbol
+only if it is referenced and is not defined by any object included in
+the link. For example, traditional linkers defined the symbol 'etext'.
+However, ANSI C requires that the user be able to use 'etext' as a
+function name without encountering an error. The 'PROVIDE' keyword may
+be used to define a symbol, such as 'etext', only if it is referenced
+but not defined. The syntax is 'PROVIDE(SYMBOL = EXPRESSION)'.
+
+ Here is an example of using 'PROVIDE' to define 'etext':
+ SECTIONS
+ {
+ .text :
+ {
+ *(.text)
+ _etext = .;
+ PROVIDE(etext = .);
+ }
+ }
+
+ In this example, if the program defines '_etext' (with a leading
+underscore), the linker will give a multiple definition error. If, on
+the other hand, the program defines 'etext' (with no leading
+underscore), the linker will silently use the definition in the program.
+If the program references 'etext' but does not define it, the linker
+will use the definition in the linker script.
+
+3.5.3 PROVIDE_HIDDEN
+--------------------
+
+Similar to 'PROVIDE'. For ELF targeted ports, the symbol will be hidden
+and won't be exported.
+
+3.5.4 Source Code Reference
+---------------------------
+
+Accessing a linker script defined variable from source code is not
+intuitive. In particular a linker script symbol is not equivalent to a
+variable declaration in a high level language, it is instead a symbol
+that does not have a value.
+
+ Before going further, it is important to note that compilers often
+transform names in the source code into different names when they are
+stored in the symbol table. For example, Fortran compilers commonly
+prepend or append an underscore, and C++ performs extensive 'name
+mangling'. Therefore there might be a discrepancy between the name of a
+variable as it is used in source code and the name of the same variable
+as it is defined in a linker script. For example in C a linker script
+variable might be referred to as:
+
+ extern int foo;
+
+ But in the linker script it might be defined as:
+
+ _foo = 1000;
+
+ In the remaining examples however it is assumed that no name
+transformation has taken place.
+
+ When a symbol is declared in a high level language such as C, two
+things happen. The first is that the compiler reserves enough space in
+the program's memory to hold the _value_ of the symbol. The second is
+that the compiler creates an entry in the program's symbol table which
+holds the symbol's _address_. ie the symbol table contains the address
+of the block of memory holding the symbol's value. So for example the
+following C declaration, at file scope:
+
+ int foo = 1000;
+
+ creates a entry called 'foo' in the symbol table. This entry holds
+the address of an 'int' sized block of memory where the number 1000 is
+initially stored.
+
+ When a program references a symbol the compiler generates code that
+first accesses the symbol table to find the address of the symbol's
+memory block and then code to read the value from that memory block.
+So:
+
+ foo = 1;
+
+ looks up the symbol 'foo' in the symbol table, gets the address
+associated with this symbol and then writes the value 1 into that
+address. Whereas:
+
+ int * a = & foo;
+
+ looks up the symbol 'foo' in the symbol table, gets it address and
+then copies this address into the block of memory associated with the
+variable 'a'.
+
+ Linker scripts symbol declarations, by contrast, create an entry in
+the symbol table but do not assign any memory to them. Thus they are an
+address without a value. So for example the linker script definition:
+
+ foo = 1000;
+
+ creates an entry in the symbol table called 'foo' which holds the
+address of memory location 1000, but nothing special is stored at
+address 1000. This means that you cannot access the _value_ of a linker
+script defined symbol - it has no value - all you can do is access the
+_address_ of a linker script defined symbol.
+
+ Hence when you are using a linker script defined symbol in source
+code you should always take the address of the symbol, and never attempt
+to use its value. For example suppose you want to copy the contents of
+a section of memory called .ROM into a section called .FLASH and the
+linker script contains these declarations:
+
+ start_of_ROM = .ROM;
+ end_of_ROM = .ROM + sizeof (.ROM) - 1;
+ start_of_FLASH = .FLASH;
+
+ Then the C source code to perform the copy would be:
+
+ extern char start_of_ROM, end_of_ROM, start_of_FLASH;
+
+ memcpy (& start_of_FLASH, & start_of_ROM, & end_of_ROM - & start_of_ROM);
+
+ Note the use of the '&' operators. These are correct.
+
+3.6 SECTIONS Command
+====================
+
+The 'SECTIONS' command tells the linker how to map input sections into
+output sections, and how to place the output sections in memory.
+
+ The format of the 'SECTIONS' command is:
+ SECTIONS
+ {
+ SECTIONS-COMMAND
+ SECTIONS-COMMAND
+ ...
+ }
+
+ Each SECTIONS-COMMAND may of be one of the following:
+
+ * an 'ENTRY' command (*note Entry command: Entry Point.)
+ * a symbol assignment (*note Assignments::)
+ * an output section description
+ * an overlay description
+
+ The 'ENTRY' command and symbol assignments are permitted inside the
+'SECTIONS' command for convenience in using the location counter in
+those commands. This can also make the linker script easier to
+understand because you can use those commands at meaningful points in
+the layout of the output file.
+
+ Output section descriptions and overlay descriptions are described
+below.
+
+ If you do not use a 'SECTIONS' command in your linker script, the
+linker will place each input section into an identically named output
+section in the order that the sections are first encountered in the
+input files. If all input sections are present in the first file, for
+example, the order of sections in the output file will match the order
+in the first input file. The first section will be at address zero.
+
+3.6.1 Output Section Description
+--------------------------------
+
+The full description of an output section looks like this:
+ SECTION [ADDRESS] [(TYPE)] :
+ [AT(LMA)] [ALIGN(SECTION_ALIGN)] [SUBALIGN(SUBSECTION_ALIGN)]
+ {
+ OUTPUT-SECTION-COMMAND
+ OUTPUT-SECTION-COMMAND
+ ...
+ } [>REGION] [AT>LMA_REGION] [:PHDR :PHDR ...] [=FILLEXP]
+
+ Most output sections do not use most of the optional section
+attributes.
+
+ The whitespace around SECTION is required, so that the section name
+is unambiguous. The colon and the curly braces are also required. The
+line breaks and other white space are optional.
+
+ Each OUTPUT-SECTION-COMMAND may be one of the following:
+
+ * a symbol assignment (*note Assignments::)
+ * an input section description (*note Input Section::)
+ * data values to include directly (*note Output Section Data::)
+ * a special output section keyword (*note Output Section Keywords::)
+
+3.6.2 Output Section Name
+-------------------------
+
+The name of the output section is SECTION. SECTION must meet the
+constraints of your output format. In formats which only support a
+limited number of sections, such as 'a.out', the name must be one of the
+names supported by the format ('a.out', for example, allows only
+'.text', '.data' or '.bss'). If the output format supports any number
+of sections, but with numbers and not names (as is the case for Oasys),
+the name should be supplied as a quoted numeric string. A section name
+may consist of any sequence of characters, but a name which contains any
+unusual characters such as commas must be quoted.
+
+ The output section name '/DISCARD/' is special; *note Output Section
+Discarding::.
+
+3.6.3 Output Section Address
+----------------------------
+
+The ADDRESS is an expression for the VMA (the virtual memory address) of
+the output section. If you do not provide ADDRESS, the linker will set
+it based on REGION if present, or otherwise based on the current value
+of the location counter.
+
+ If you provide ADDRESS, the address of the output section will be set
+to precisely that. If you provide neither ADDRESS nor REGION, then the
+address of the output section will be set to the current value of the
+location counter aligned to the alignment requirements of the output
+section. The alignment requirement of the output section is the
+strictest alignment of any input section contained within the output
+section.
+
+ For example,
+ .text . : { *(.text) }
+and
+ .text : { *(.text) }
+are subtly different. The first will set the address of the '.text'
+output section to the current value of the location counter. The second
+will set it to the current value of the location counter aligned to the
+strictest alignment of a '.text' input section.
+
+ The ADDRESS may be an arbitrary expression; *note Expressions::. For
+example, if you want to align the section on a 0x10 byte boundary, so
+that the lowest four bits of the section address are zero, you could do
+something like this:
+ .text ALIGN(0x10) : { *(.text) }
+This works because 'ALIGN' returns the current location counter aligned
+upward to the specified value.
+
+ Specifying ADDRESS for a section will change the value of the
+location counter.
+
+3.6.4 Input Section Description
+-------------------------------
+
+The most common output section command is an input section description.
+
+ The input section description is the most basic linker script
+operation. You use output sections to tell the linker how to lay out
+your program in memory. You use input section descriptions to tell the
+linker how to map the input files into your memory layout.
+
+3.6.4.1 Input Section Basics
+............................
+
+An input section description consists of a file name optionally followed
+by a list of section names in parentheses.
+
+ The file name and the section name may be wildcard patterns, which we
+describe further below (*note Input Section Wildcards::).
+
+ The most common input section description is to include all input
+sections with a particular name in the output section. For example, to
+include all input '.text' sections, you would write:
+ *(.text)
+Here the '*' 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:
+ (*(EXCLUDE_FILE (*crtend.o *otherfile.o) .ctors))
+ will cause all .ctors sections from all files except 'crtend.o' and
+'otherfile.o' to be included.
+
+ There are two ways to include more than one section:
+ *(.text .rdata)
+ *(.text) *(.rdata)
+The difference between these is the order in which the '.text' and
+'.rdata' input sections will appear in the output section. In the first
+example, they will be intermingled, appearing in the same order as they
+are found in the linker input. In the second example, all '.text' input
+sections will appear first, followed by all '.rdata' input sections.
+
+ You can specify a file name to include sections from a particular
+file. You would do this if one or more of your files contain special
+data that needs to be at a particular location in memory. For example:
+ data.o(.data)
+
+ If you use a file name without a list of sections, then all sections
+in the input file will be included in the output section. This is not
+commonly done, but it may by useful on occasion. For example:
+ data.o
+
+ When you use a file name which does not contain any wild card
+characters, the linker will first see if you also specified the file
+name on the linker command line or in an 'INPUT' command. If you did
+not, the linker will attempt to open the file as an input file, as
+though it appeared on the command line. Note that this differs from an
+'INPUT' command, because the linker will not search for the file in the
+archive search path.
+
+3.6.4.2 Input Section Wildcard Patterns
+.......................................
+
+In an input section description, either the file name or the section
+name or both may be wildcard patterns.
+
+ The file name of '*' seen in many examples is a simple wildcard
+pattern for the file name.
+
+ The wildcard patterns are like those used by the Unix shell.
+
+'*'
+ matches any number of characters
+'?'
+ matches any single character
+'[CHARS]'
+ matches a single instance of any of the CHARS; the '-' character
+ may be used to specify a range of characters, as in '[a-z]' to
+ match any lower case letter
+'\'
+ quotes the following character
+
+ When a file name is matched with a wildcard, the wildcard characters
+will not match a '/' character (used to separate directory names on
+Unix). A pattern consisting of a single '*' character is an exception;
+it will always match any file name, whether it contains a '/' or not.
+In a section name, the wildcard characters will match a '/' character.
+
+ File name wildcard patterns only match files which are explicitly
+specified on the command line or in an 'INPUT' command. The linker does
+not search directories to expand wildcards.
+
+ If a file name matches more than one wildcard pattern, or if a file
+name appears explicitly and is also matched by a wildcard pattern, the
+linker will use the first match in the linker script. For example, this
+sequence of input section descriptions is probably in error, because the
+'data.o' rule will not be used:
+ .data : { *(.data) }
+ .data1 : { data.o(.data) }
+
+ Normally, the linker will place files and sections matched by
+wildcards in the order in which they are seen during the link. You can
+change this by using the 'SORT_BY_NAME' keyword, which appears before a
+wildcard pattern in parentheses (e.g., 'SORT_BY_NAME(.text*)'). When
+the 'SORT_BY_NAME' keyword is used, the linker will sort the files or
+sections into ascending order by name before placing them in the output
+file.
+
+ 'SORT_BY_ALIGNMENT' is very similar to 'SORT_BY_NAME'. The
+difference is 'SORT_BY_ALIGNMENT' will sort sections into ascending
+order by alignment before placing them in the output file.
+
+ 'SORT' is an alias for 'SORT_BY_NAME'.
+
+ When there are nested section sorting commands in linker script,
+there can be at most 1 level of nesting for section sorting commands.
+
+ 1. 'SORT_BY_NAME' ('SORT_BY_ALIGNMENT' (wildcard section pattern)).
+ It will sort the input sections by name first, then by alignment if
+ 2 sections have the same name.
+ 2. 'SORT_BY_ALIGNMENT' ('SORT_BY_NAME' (wildcard section pattern)).
+ It will sort the input sections by alignment first, then by name if
+ 2 sections have the same alignment.
+ 3. 'SORT_BY_NAME' ('SORT_BY_NAME' (wildcard section pattern)) is
+ treated the same as 'SORT_BY_NAME' (wildcard section pattern).
+ 4. 'SORT_BY_ALIGNMENT' ('SORT_BY_ALIGNMENT' (wildcard section
+ pattern)) is treated the same as 'SORT_BY_ALIGNMENT' (wildcard
+ section pattern).
+ 5. All other nested section sorting commands are invalid.
+
+ When both command line section sorting option and linker script
+section sorting command are used, section sorting command always takes
+precedence over the command line option.
+
+ If the section sorting command in linker script isn't nested, the
+command line option will make the section sorting command to be treated
+as nested sorting command.
+
+ 1. 'SORT_BY_NAME' (wildcard section pattern ) with '--sort-sections
+ alignment' is equivalent to 'SORT_BY_NAME' ('SORT_BY_ALIGNMENT'
+ (wildcard section pattern)).
+ 2. 'SORT_BY_ALIGNMENT' (wildcard section pattern) with '--sort-section
+ name' is equivalent to 'SORT_BY_ALIGNMENT' ('SORT_BY_NAME'
+ (wildcard section pattern)).
+
+ If the section sorting command in linker script is nested, the
+command line option will be ignored.
+
+ If you ever get confused about where input sections are going, use
+the '-M' linker option to generate a map file. The map file shows
+precisely how input sections are mapped to output sections.
+
+ This example shows how wildcard patterns might be used to partition
+files. This linker script directs the linker to place all '.text'
+sections in '.text' and all '.bss' sections in '.bss'. The linker will
+place the '.data' section from all files beginning with an upper case
+character in '.DATA'; for all other files, the linker will place the
+'.data' section in '.data'.
+ SECTIONS {
+ .text : { *(.text) }
+ .DATA : { [A-Z]*(.data) }
+ .data : { *(.data) }
+ .bss : { *(.bss) }
+ }
+
+3.6.4.3 Input Section for Common Symbols
+........................................
+
+A special notation is needed for common symbols, because in many object
+file formats common symbols do not have a particular input section. The
+linker treats common symbols as though they are in an input section
+named 'COMMON'.
+
+ You may use file names with the 'COMMON' section just as with any
+other input sections. You can use this to place common symbols from a
+particular input file in one section while common symbols from other
+input files are placed in another section.
+
+ In most cases, common symbols in input files will be placed in the
+'.bss' section in the output file. For example:
+ .bss { *(.bss) *(COMMON) }
+
+ Some object file formats have more than one type of common symbol.
+For example, the MIPS ELF object file format distinguishes standard
+common symbols and small common symbols. In this case, the linker will
+use a different special section name for other types of common symbols.
+In the case of MIPS ELF, the linker uses 'COMMON' for standard common
+symbols and '.scommon' for small common symbols. This permits you to
+map the different types of common symbols into memory at different
+locations.
+
+ You will sometimes see '[COMMON]' in old linker scripts. This
+notation is now considered obsolete. It is equivalent to '*(COMMON)'.
+
+3.6.4.4 Input Section and Garbage Collection
+............................................
+
+When link-time garbage collection is in use ('--gc-sections'), it is
+often useful to mark sections that should not be eliminated. This is
+accomplished by surrounding an input section's wildcard entry with
+'KEEP()', as in 'KEEP(*(.init))' or 'KEEP(SORT_BY_NAME(*)(.ctors))'.
+
+3.6.4.5 Input Section Example
+.............................
+
+The following example is a complete linker script. It tells the linker
+to read all of the sections from file 'all.o' and place them at the
+start of output section 'outputa' which starts at location '0x10000'.
+All of section '.input1' from file 'foo.o' follows immediately, in the
+same output section. All of section '.input2' from 'foo.o' goes into
+output section 'outputb', followed by section '.input1' from 'foo1.o'.
+All of the remaining '.input1' and '.input2' sections from any files are
+written to output section 'outputc'.
+
+ SECTIONS {
+ outputa 0x10000 :
+ {
+ all.o
+ foo.o (.input1)
+ }
+ outputb :
+ {
+ foo.o (.input2)
+ foo1.o (.input1)
+ }
+ outputc :
+ {
+ *(.input1)
+ *(.input2)
+ }
+ }
+
+3.6.5 Output Section Data
+-------------------------
+
+You can include explicit bytes of data in an output section by using
+'BYTE', 'SHORT', 'LONG', 'QUAD', or 'SQUAD' as an output section
+command. Each keyword is followed by an expression in parentheses
+providing the value to store (*note Expressions::). The value of the
+expression is stored at the current value of the location counter.
+
+ The 'BYTE', 'SHORT', 'LONG', and 'QUAD' commands store one, two,
+four, and eight bytes (respectively). After storing the bytes, the
+location counter is incremented by the number of bytes stored.
+
+ For example, this will store the byte 1 followed by the four byte
+value of the symbol 'addr':
+ BYTE(1)
+ LONG(addr)
+
+ When using a 64 bit host or target, 'QUAD' and 'SQUAD' are the same;
+they both store an 8 byte, or 64 bit, value. When both host and target
+are 32 bits, an expression is computed as 32 bits. In this case 'QUAD'
+stores a 32 bit value zero extended to 64 bits, and 'SQUAD' stores a 32
+bit value sign extended to 64 bits.
+
+ If the object file format of the output file has an explicit
+endianness, which is the normal case, the value will be stored in that
+endianness. When the object file format does not have an explicit
+endianness, as is 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:
+ SECTIONS { .text : { *(.text) } LONG(1) .data : { *(.data) } }
+ whereas this will work:
+ SECTIONS { .text : { *(.text) ; LONG(1) } .data : { *(.data) } }
+
+ You may use the 'FILL' command to set the fill pattern for the
+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 value of the expression, repeated as necessary. A 'FILL'
+statement covers memory locations after the point at which it occurs in
+the section definition; by including more than one '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 '0x90':
+ FILL(0x90909090)
+
+ The 'FILL' command is similar to the '=FILLEXP' output section
+attribute, but it only affects the part of the section following the
+'FILL' command, rather than the entire section. If both are used, the
+'FILL' command takes precedence. *Note Output Section Fill::, for
+details on the fill expression.
+
+3.6.6 Output Section Keywords
+-----------------------------
+
+There are a couple of keywords which can appear as output section
+commands.
+
+'CREATE_OBJECT_SYMBOLS'
+ The command tells the linker to create a symbol for each input
+ file. The name of each symbol will be the name of the
+ corresponding input file. The section of each symbol will be the
+ output section in which the 'CREATE_OBJECT_SYMBOLS' command
+ appears.
+
+ This is conventional for the a.out object file format. It is not
+ normally used for any other object file format.
+
+'CONSTRUCTORS'
+ When linking using the a.out object file format, the linker uses an
+ unusual set construct to support C++ global constructors and
+ destructors. When linking object file formats which do not support
+ arbitrary sections, such as ECOFF and XCOFF, the linker will
+ automatically recognize C++ global constructors and destructors by
+ name. For these object file formats, the 'CONSTRUCTORS' command
+ tells the linker to place constructor information in the output
+ section where the 'CONSTRUCTORS' command appears. The
+ 'CONSTRUCTORS' command is ignored for other object file formats.
+
+ The symbol '__CTOR_LIST__' marks the start of the global
+ constructors, and the symbol '__CTOR_END__' marks the end.
+ Similarly, '__DTOR_LIST__' and '__DTOR_END__' mark the start and
+ end of the global destructors. The first word in the list is the
+ number of entries, followed by the address of each constructor or
+ destructor, followed by a zero word. The compiler must arrange to
+ actually run the code. For these object file formats GNU C++
+ normally calls constructors from a subroutine '__main'; a call to
+ '__main' is automatically inserted into the startup code for
+ 'main'. GNU C++ normally runs destructors either by using
+ 'atexit', or directly from the function 'exit'.
+
+ For object file formats such as 'COFF' or 'ELF' which support
+ arbitrary section names, GNU C++ will normally arrange to put the
+ addresses of global constructors and destructors into the '.ctors'
+ and '.dtors' sections. Placing the following sequence into your
+ linker script will build the sort of table which the GNU C++
+ runtime code expects to see.
+
+ __CTOR_LIST__ = .;
+ LONG((__CTOR_END__ - __CTOR_LIST__) / 4 - 2)
+ *(.ctors)
+ LONG(0)
+ __CTOR_END__ = .;
+ __DTOR_LIST__ = .;
+ LONG((__DTOR_END__ - __DTOR_LIST__) / 4 - 2)
+ *(.dtors)
+ LONG(0)
+ __DTOR_END__ = .;
+
+ If you are using the GNU C++ support for initialization priority,
+ which provides some control over the order in which global
+ constructors are run, you must sort the constructors at link time
+ to ensure that they are executed in the correct order. When using
+ the 'CONSTRUCTORS' command, use 'SORT_BY_NAME(CONSTRUCTORS)'
+ instead. When using the '.ctors' and '.dtors' sections, use
+ '*(SORT_BY_NAME(.ctors))' and '*(SORT_BY_NAME(.dtors))' instead of
+ just '*(.ctors)' and '*(.dtors)'.
+
+ Normally the compiler and linker will handle these issues
+ automatically, and you will not need to concern yourself with them.
+ However, you may need to consider this if you are using C++ and
+ writing your own linker scripts.
+
+3.6.7 Output Section Discarding
+-------------------------------
+
+The linker will not create output sections with no contents. This is
+for convenience when referring to input sections that may or may not be
+present in any of the input files. For example:
+ .foo : { *(.foo) }
+will only create a '.foo' section in the output file if there is a
+'.foo' section in at least one input file, and if the input sections are
+not all empty. Other link script directives that allocate space in an
+output section will also create the output section.
+
+ The linker will ignore address assignments (*note Output Section
+Address::) on discarded output sections, except when the linker script
+defines symbols in the output section. In that case the linker will
+obey the address assignments, possibly advancing dot even though the
+section is discarded.
+
+ The special output section name '/DISCARD/' may be used to discard
+input sections. Any input sections which are assigned to an output
+section named '/DISCARD/' are not included in the output file.
+
+3.6.8 Output Section Attributes
+-------------------------------
+
+We showed above that the full description of an output section looked
+like this:
+ SECTION [ADDRESS] [(TYPE)] :
+ [AT(LMA)] [ALIGN(SECTION_ALIGN)] [SUBALIGN(SUBSECTION_ALIGN)]
+ {
+ OUTPUT-SECTION-COMMAND
+ OUTPUT-SECTION-COMMAND
+ ...
+ } [>REGION] [AT>LMA_REGION] [:PHDR :PHDR ...] [=FILLEXP]
+ We've already described SECTION, ADDRESS, and OUTPUT-SECTION-COMMAND.
+In this section we will describe the remaining section attributes.
+
+3.6.8.1 Output Section Type
+...........................
+
+Each output section may have a type. The type is a keyword in
+parentheses. The following types are defined:
+
+'NOLOAD'
+ The section should be marked as not loadable, so that it will not
+ be loaded into memory when the program is run.
+'DSECT'
+'COPY'
+'INFO'
+'OVERLAY'
+ These type names are supported for backward compatibility, and are
+ rarely used. They all have the same effect: the section should be
+ marked as not allocatable, so that no memory is allocated for the
+ section when the program is run.
+
+ The linker normally sets the attributes of an output section based on
+the input sections which map into it. You can override this by using
+the section type. For example, in the script sample below, the 'ROM'
+section is addressed at memory location '0' and does not need to be
+loaded when the program is run. The contents of the 'ROM' section will
+appear in the linker output file as usual.
+ SECTIONS {
+ ROM 0 (NOLOAD) : { ... }
+ ...
+ }
+
+3.6.8.2 Output Section LMA
+..........................
+
+Every section has a virtual address (VMA) and a load address (LMA); see
+*note Basic Script Concepts::. The address expression which may appear
+in an output section description sets the VMA (*note Output Section
+Address::).
+
+ The expression LMA that follows the 'AT' keyword specifies the load
+address of the section.
+
+ Alternatively, with 'AT>LMA_REGION' expression, you may specify a
+memory region for the section's load address. *Note MEMORY::. Note
+that if the section has not had a VMA assigned to it then the linker
+will use the LMA_REGION as the VMA region as well.
+
+ If neither 'AT' nor 'AT>' is specified for an allocatable section,
+the linker will set the LMA such that the difference between VMA and LMA
+for the section is the same as the preceding output section in the same
+region. If there is no preceding output section or the section is not
+allocatable, the linker will set the LMA equal to the VMA. *Note Output
+Section Region::.
+
+ This feature is designed to make it easy to build a ROM image. For
+example, the following linker script creates three output sections: one
+called '.text', which starts at '0x1000', one called '.mdata', which is
+loaded at the end of the '.text' section even though its VMA is
+'0x2000', and one called '.bss' to hold uninitialized data at address
+'0x3000'. The symbol '_data' is defined with the value '0x2000', which
+shows that the location counter holds the VMA value, not the LMA value.
+
+ SECTIONS
+ {
+ .text 0x1000 : { *(.text) _etext = . ; }
+ .mdata 0x2000 :
+ AT ( ADDR (.text) + SIZEOF (.text) )
+ { _data = . ; *(.data); _edata = . ; }
+ .bss 0x3000 :
+ { _bstart = . ; *(.bss) *(COMMON) ; _bend = . ;}
+ }
+
+ The run-time initialization code for use with a program generated
+with this linker script would include something like the following, to
+copy the initialized data from the ROM image to its runtime address.
+Notice how this code takes advantage of the symbols defined by the
+linker script.
+
+ extern char _etext, _data, _edata, _bstart, _bend;
+ char *src = &_etext;
+ char *dst = &_data;
+
+ /* ROM has data at end of text; copy it. */
+ while (dst < &_edata) {
+ *dst++ = *src++;
+ }
+
+ /* Zero bss */
+ for (dst = &_bstart; dst< &_bend; dst++)
+ *dst = 0;
+
+3.6.8.3 Forced Output Alignment
+...............................
+
+You can increase an output section's alignment by using ALIGN.
+
+3.6.8.4 Forced Input Alignment
+..............................
+
+You can force input section alignment within an output section by using
+SUBALIGN. The value specified overrides any alignment given by input
+sections, whether larger or smaller.
+
+3.6.8.5 Output Section Region
+.............................
+
+You can assign a section to a previously defined region of memory by
+using '>REGION'. *Note MEMORY::.
+
+ Here is a simple example:
+ MEMORY { rom : ORIGIN = 0x1000, LENGTH = 0x1000 }
+ SECTIONS { ROM : { *(.text) } >rom }
+
+3.6.8.6 Output Section Phdr
+...........................
+
+You can assign a section to a previously defined program segment by
+using ':PHDR'. *Note PHDRS::. If a section is assigned to one or more
+segments, then all subsequent allocated sections will be assigned to
+those segments as well, unless they use an explicitly ':PHDR' modifier.
+You can use ':NONE' to tell the linker to not put the section in any
+segment at all.
+
+ Here is a simple example:
+ PHDRS { text PT_LOAD ; }
+ SECTIONS { .text : { *(.text) } :text }
+
+3.6.8.7 Output Section Fill
+...........................
+
+You can set the fill pattern for an entire section by using '=FILLEXP'.
+FILLEXP is an expression (*note 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 value, repeated as necessary. If the fill expression is
+a simple hex number, ie. a string of hex digit starting with '0x' and
+without a trailing 'k' or '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 '+', 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 'FILL' command in the
+output section commands; (*note Output Section Data::).
+
+ Here is a simple example:
+ SECTIONS { .text : { *(.text) } =0x90909090 }
+
+3.6.9 Overlay Description
+-------------------------
+
+An overlay description provides an easy way to describe sections which
+are to be loaded as part of a single memory image but are to be run at
+the same memory address. At run time, some sort of overlay manager will
+copy the overlaid sections in and out of the runtime memory address as
+required, perhaps by simply manipulating addressing bits. This approach
+can be useful, for example, when a certain region of memory is faster
+than another.
+
+ Overlays are described using the 'OVERLAY' command. The 'OVERLAY'
+command is used within a 'SECTIONS' command, like an output section
+description. The full syntax of the 'OVERLAY' command is as follows:
+ OVERLAY [START] : [NOCROSSREFS] [AT ( LDADDR )]
+ {
+ SECNAME1
+ {
+ OUTPUT-SECTION-COMMAND
+ OUTPUT-SECTION-COMMAND
+ ...
+ } [:PHDR...] [=FILL]
+ SECNAME2
+ {
+ OUTPUT-SECTION-COMMAND
+ OUTPUT-SECTION-COMMAND
+ ...
+ } [:PHDR...] [=FILL]
+ ...
+ } [>REGION] [:PHDR...] [=FILL]
+
+ Everything is optional except 'OVERLAY' (a keyword), and each section
+must have a name (SECNAME1 and SECNAME2 above). The section definitions
+within the 'OVERLAY' construct are identical to those within the general
+'SECTIONS' contruct (*note SECTIONS::), except that no addresses and no
+memory regions may be defined for sections within an 'OVERLAY'.
+
+ The sections are all defined with the same starting address. The
+load addresses of the sections are arranged such that they are
+consecutive in memory starting at the load address used for the
+'OVERLAY' as a whole (as with normal section definitions, the load
+address is optional, and defaults to the start address; the start
+address is also optional, and defaults to the current value of the
+location counter).
+
+ If the 'NOCROSSREFS' keyword is used, and there any references among
+the sections, the linker will report an error. Since the sections all
+run at the same address, it normally does not make sense for one section
+to refer directly to another. *Note NOCROSSREFS: Miscellaneous
+Commands.
+
+ For each section within the 'OVERLAY', the linker automatically
+provides two symbols. The symbol '__load_start_SECNAME' is defined as
+the starting load address of the section. The symbol
+'__load_stop_SECNAME' is defined as the final load address of the
+section. Any characters within SECNAME which are not legal within C
+identifiers are removed. C (or assembler) code may use these symbols to
+move the overlaid sections around as necessary.
+
+ At the end of the overlay, the value of the location counter is set
+to the start address of the overlay plus the size of the largest
+section.
+
+ Here is an example. Remember that this would appear inside a
+'SECTIONS' construct.
+ OVERLAY 0x1000 : AT (0x4000)
+ {
+ .text0 { o1/*.o(.text) }
+ .text1 { o2/*.o(.text) }
+ }
+This will define both '.text0' and '.text1' to start at address 0x1000.
+'.text0' will be loaded at address 0x4000, and '.text1' will be loaded
+immediately after '.text0'. The following symbols will be defined if
+referenced: '__load_start_text0', '__load_stop_text0',
+'__load_start_text1', '__load_stop_text1'.
+
+ C code to copy overlay '.text1' into the overlay area might look like
+the following.
+
+ extern char __load_start_text1, __load_stop_text1;
+ memcpy ((char *) 0x1000, &__load_start_text1,
+ &__load_stop_text1 - &__load_start_text1);
+
+ Note that the 'OVERLAY' command is just syntactic sugar, since
+everything it does can be done using the more basic commands. The above
+example could have been written identically as follows.
+
+ .text0 0x1000 : AT (0x4000) { o1/*.o(.text) }
+ PROVIDE (__load_start_text0 = LOADADDR (.text0));
+ PROVIDE (__load_stop_text0 = LOADADDR (.text0) + SIZEOF (.text0));
+ .text1 0x1000 : AT (0x4000 + SIZEOF (.text0)) { o2/*.o(.text) }
+ PROVIDE (__load_start_text1 = LOADADDR (.text1));
+ PROVIDE (__load_stop_text1 = LOADADDR (.text1) + SIZEOF (.text1));
+ . = 0x1000 + MAX (SIZEOF (.text0), SIZEOF (.text1));
+
+3.7 MEMORY Command
+==================
+
+The linker's default configuration permits allocation of all available
+memory. You can override this by using the 'MEMORY' command.
+
+ The 'MEMORY' command describes the location and size of blocks of
+memory in the target. You can use it to describe which memory regions
+may be used by the linker, and which memory regions it must avoid. You
+can then assign sections to particular memory regions. The linker will
+set section addresses based on the memory regions, and will warn about
+regions that become too full. The linker will not shuffle sections
+around to fit into the available regions.
+
+ A linker script may contain at most one use of the 'MEMORY' command.
+However, you can define as many blocks of memory within it as you wish.
+The syntax is:
+ MEMORY
+ {
+ NAME [(ATTR)] : ORIGIN = ORIGIN, LENGTH = LEN
+ ...
+ }
+
+ The NAME is a name used in the linker script to refer to the region.
+The region name has no meaning outside of the linker script. Region
+names are stored in a separate name space, and will not conflict with
+symbol names, file names, or section names. Each memory region must
+have a distinct name.
+
+ The ATTR string is an optional list of attributes that specify
+whether to use a particular memory region for an input section which is
+not explicitly mapped in the linker script. As described in *note
+SECTIONS::, if you do not specify an output section for some input
+section, the linker will create an output section with the same name as
+the input section. If you define region attributes, the linker will use
+them to select the memory region for the output section that it creates.
+
+ The ATTR string must consist only of the following characters:
+'R'
+ Read-only section
+'W'
+ Read/write section
+'X'
+ Executable section
+'A'
+ Allocatable section
+'I'
+ Initialized section
+'L'
+ Same as 'I'
+'!'
+ Invert the sense of any of the preceding attributes
+
+ If a unmapped section matches any of the listed attributes other than
+'!', it will be placed in the memory region. The '!' attribute reverses
+this test, so that an unmapped section will be placed in the memory
+region only if it does not match any of the listed attributes.
+
+ The ORIGIN is an numerical expression for the start address of the
+memory region. The expression must evaluate to a constant and it cannot
+involve any symbols. The keyword 'ORIGIN' may be abbreviated to 'org'
+or 'o' (but not, for example, 'ORG').
+
+ The LEN is an expression for the size in bytes of the memory region.
+As with the ORIGIN expression, the expression must be numerical only and
+must evaluate to a constant. The keyword 'LENGTH' may be abbreviated to
+'len' or 'l'.
+
+ In the following example, we specify that there are two memory
+regions available for allocation: one starting at '0' for 256 kilobytes,
+and the other starting at '0x40000000' for four megabytes. The linker
+will place into the 'rom' memory region every section which is not
+explicitly mapped into a memory region, and is either read-only or
+executable. The linker will place other sections which are not
+explicitly mapped into a memory region into the 'ram' memory region.
+
+ MEMORY
+ {
+ rom (rx) : ORIGIN = 0, LENGTH = 256K
+ ram (!rx) : org = 0x40000000, l = 4M
+ }
+
+ Once you define a memory region, you can direct the linker to place
+specific output sections into that memory region by using the '>REGION'
+output section attribute. For example, if you have a memory region
+named 'mem', you would use '>mem' in the output section definition.
+*Note Output Section Region::. If no address was specified for the
+output section, the linker will set the address to the next available
+address within the memory region. If the combined output sections
+directed to a memory region are too large for the region, the linker
+will issue an error message.
+
+ It is possible to access the origin and length of a memory in an
+expression via the 'ORIGIN(MEMORY)' and 'LENGTH(MEMORY)' functions:
+
+ _fstack = ORIGIN(ram) + LENGTH(ram) - 4;
+
+3.8 PHDRS Command
+=================
+
+The ELF object file format uses "program headers", also knows as
+"segments". The program headers describe how the program should be
+loaded into memory. You can print them out by using the 'objdump'
+program with the '-p' option.
+
+ When you run an ELF program on a native ELF system, the system loader
+reads the program headers in order to figure out how to load the
+program. This will only work if the program headers are set correctly.
+This manual does not describe the details of how the system loader
+interprets program headers; for more information, see the ELF ABI.
+
+ The linker will create reasonable program headers by default.
+However, in some cases, you may need to specify the program headers more
+precisely. You may use the 'PHDRS' command for this purpose. When the
+linker sees the 'PHDRS' command in the linker script, it will not create
+any program headers other than the ones specified.
+
+ The linker only pays attention to the 'PHDRS' command when generating
+an ELF output file. In other cases, the linker will simply ignore
+'PHDRS'.
+
+ This is the syntax of the 'PHDRS' command. The words 'PHDRS',
+'FILEHDR', 'AT', and 'FLAGS' are keywords.
+
+ PHDRS
+ {
+ NAME TYPE [ FILEHDR ] [ PHDRS ] [ AT ( ADDRESS ) ]
+ [ FLAGS ( FLAGS ) ] ;
+ }
+
+ The NAME is used only for reference in the 'SECTIONS' command of the
+linker script. It is not put into the output file. Program header
+names are stored in a separate name space, and will not conflict with
+symbol names, file names, or section names. Each program header must
+have a distinct name.
+
+ Certain program header types describe segments of memory which the
+system loader will load from the file. In the linker script, you
+specify the contents of these segments by placing allocatable output
+sections in the segments. You use the ':PHDR' output section attribute
+to place a section in a particular segment. *Note Output Section
+Phdr::.
+
+ It is normal to put certain sections in more than one segment. This
+merely implies that one segment of memory contains another. You may
+repeat ':PHDR', using it once for each segment which should contain the
+section.
+
+ If you place a section in one or more segments using ':PHDR', then
+the linker will place all subsequent allocatable sections which do not
+specify ':PHDR' in the same segments. This is for convenience, since
+generally a whole set of contiguous sections will be placed in a single
+segment. You can use ':NONE' to override the default segment and tell
+the linker to not put the section in any segment at all.
+
+ You may use the 'FILEHDR' and 'PHDRS' keywords appear after the
+program header type to further describe the contents of the segment.
+The 'FILEHDR' keyword means that the segment should include the ELF file
+header. The 'PHDRS' keyword means that the segment should include the
+ELF program headers themselves.
+
+ The TYPE may be one of the following. The numbers indicate the value
+of the keyword.
+
+'PT_NULL' (0)
+ Indicates an unused program header.
+
+'PT_LOAD' (1)
+ Indicates that this program header describes a segment to be loaded
+ from the file.
+
+'PT_DYNAMIC' (2)
+ Indicates a segment where dynamic linking information can be found.
+
+'PT_INTERP' (3)
+ Indicates a segment where the name of the program interpreter may
+ be found.
+
+'PT_NOTE' (4)
+ Indicates a segment holding note information.
+
+'PT_SHLIB' (5)
+ A reserved program header type, defined but not specified by the
+ ELF ABI.
+
+'PT_PHDR' (6)
+ Indicates a segment where the program headers may be found.
+
+EXPRESSION
+ An expression giving the numeric type of the program header. This
+ may be used for types not defined above.
+
+ You can specify that a segment should be loaded at a particular
+address in memory by using an 'AT' expression. This is identical to the
+'AT' command used as an output section attribute (*note Output Section
+LMA::). The 'AT' command for a program header overrides the output
+section attribute.
+
+ The linker will normally set the segment flags based on the sections
+which comprise the segment. You may use the 'FLAGS' keyword to
+explicitly specify the segment flags. The value of FLAGS must be an
+integer. It is used to set the 'p_flags' field of the program header.
+
+ Here is an example of 'PHDRS'. This shows a typical set of program
+headers used on a native ELF system.
+
+ PHDRS
+ {
+ headers PT_PHDR PHDRS ;
+ interp PT_INTERP ;
+ text PT_LOAD FILEHDR PHDRS ;
+ data PT_LOAD ;
+ dynamic PT_DYNAMIC ;
+ }
+
+ SECTIONS
+ {
+ . = SIZEOF_HEADERS;
+ .interp : { *(.interp) } :text :interp
+ .text : { *(.text) } :text
+ .rodata : { *(.rodata) } /* defaults to :text */
+ ...
+ . = . + 0x1000; /* move to a new page in memory */
+ .data : { *(.data) } :data
+ .dynamic : { *(.dynamic) } :data :dynamic
+ ...
+ }
+
+3.9 VERSION Command
+===================
+
+The linker supports symbol versions when using ELF. Symbol versions are
+only useful when using shared libraries. The dynamic linker can use
+symbol versions to select a specific version of a function when it runs
+a program that may have been linked against an earlier version of the
+shared library.
+
+ You can include a version script directly in the main linker script,
+or you can supply the version script as an implicit linker script. You
+can also use the '--version-script' linker option.
+
+ The syntax of the 'VERSION' command is simply
+ VERSION { version-script-commands }
+
+ The format of the version script commands is identical to that used
+by Sun's linker in Solaris 2.5. The version script defines a tree of
+version nodes. You specify the node names and interdependencies in the
+version script. You can specify which symbols are bound to which
+version nodes, and you can reduce a specified set of symbols to local
+scope so that they are not globally visible outside of the shared
+library.
+
+ The easiest way to demonstrate the version script language is with a
+few examples.
+
+ VERS_1.1 {
+ global:
+ foo1;
+ local:
+ old*;
+ original*;
+ new*;
+ };
+
+ VERS_1.2 {
+ foo2;
+ } VERS_1.1;
+
+ VERS_2.0 {
+ bar1; bar2;
+ extern "C++" {
+ ns::*;
+ "int f(int, double)";
+ }
+ } VERS_1.2;
+
+ This example version script defines three version nodes. The first
+version node defined is 'VERS_1.1'; it has no other dependencies. The
+script binds the symbol 'foo1' to 'VERS_1.1'. It reduces a number of
+symbols to local scope so that they are not visible outside of the
+shared library; this is done using wildcard patterns, so that any symbol
+whose name begins with 'old', 'original', or 'new' is matched. The
+wildcard patterns available are the same as those used in the shell when
+matching filenames (also known as "globbing"). However, if you specify
+the symbol name inside double quotes, then the name is treated as
+literal, rather than as a glob pattern.
+
+ Next, the version script defines node 'VERS_1.2'. This node depends
+upon 'VERS_1.1'. The script binds the symbol 'foo2' to the version node
+'VERS_1.2'.
+
+ Finally, the version script defines node 'VERS_2.0'. This node
+depends upon 'VERS_1.2'. The scripts binds the symbols 'bar1' and
+'bar2' are bound to the version node 'VERS_2.0'.
+
+ 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 'global: *;'
+somewhere in the version script.
+
+ The names of the version nodes have no specific meaning other than
+what they might suggest to the person reading them. The '2.0' version
+could just as well have appeared in between '1.1' and '1.2'. However,
+this would be a confusing way to write a version script.
+
+ Node name can be omitted, 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.
+
+ { global: foo; bar; local: *; };
+
+ 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 shared library it is linked against. Thus at runtime, the dynamic
+loader can make a quick check to make sure that the libraries you have
+linked against do in fact supply all of the version nodes that the
+application will need to resolve all of the dynamic symbols. In this
+way it is possible for the dynamic linker to know with certainty that
+all external symbols that it needs will be resolvable without having to
+search for each symbol reference.
+
+ The symbol versioning is in effect a much more sophisticated way of
+doing minor version checking that SunOS does. The fundamental problem
+that is being addressed here is that typically references to external
+functions are bound on an as-needed basis, and are not all bound when
+the application starts up. If a shared library is out of date, a
+required interface may be missing; when the application tries to use
+that interface, it may suddenly and unexpectedly fail. With symbol
+versioning, the user will get a warning when they start their program if
+the libraries being used with the application are too old.
+
+ There are several GNU extensions to Sun's versioning approach. The
+first of these is the ability to bind a symbol to a version node in the
+source file where the symbol is defined instead of in the versioning
+script. This was done mainly to reduce the burden on the library
+maintainer. You can do this by putting something like:
+ __asm__(".symver original_foo,foo@VERS_1.1");
+in the C source file. This renames the function 'original_foo' to be an
+alias for 'foo' bound to the version node 'VERS_1.1'. The 'local:'
+directive can be used to prevent the symbol 'original_foo' from being
+exported. A '.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
+an incompatible change to an interface without increasing the major
+version number of the shared library, while still allowing applications
+linked against the old interface to continue to function.
+
+ To do this, you must use multiple '.symver' directives in the source
+file. Here is an example:
+
+ __asm__(".symver original_foo,foo@");
+ __asm__(".symver old_foo,foo@VERS_1.1");
+ __asm__(".symver old_foo1,foo@VERS_1.2");
+ __asm__(".symver new_foo,foo@@VERS_2.0");
+
+ In this example, 'foo@' represents the symbol 'foo' bound to the
+unspecified base version of the symbol. The source file that contains
+this example would define 4 C functions: 'original_foo', 'old_foo',
+'old_foo1', and 'new_foo'.
+
+ When you have multiple definitions of a given symbol, there needs to
+be some way to specify a default version to which external references to
+this symbol will be bound. You can do this with the 'foo@@VERS_2.0'
+type of '.symver' directive. You can only declare one version of a
+symbol as the default in this manner; otherwise you would effectively
+have multiple definitions of the same symbol.
+
+ If you wish to bind a reference to a specific version of the symbol
+within the shared library, you can use the aliases of convenience (i.e.,
+'old_foo'), or you can use the '.symver' directive to specifically bind
+to an external version of the function in question.
+
+ You can also specify the language in the version script:
+
+ VERSION extern "lang" { version-script-commands }
+
+ The supported 'lang's are 'C', 'C++', and 'Java'. The linker will
+iterate over the list of symbols at the link time and demangle them
+according to 'lang' before matching them to the patterns specified in
+'version-script-commands'.
+
+ Demangled names may contains spaces and other special characters. As
+described above, you can use a glob pattern to match demangled names, or
+you can use a double-quoted string to match the string exactly. In the
+latter case, be aware that minor differences (such as differing
+whitespace) between the version script and the demangler output will
+cause a mismatch. As the exact string generated by the demangler might
+change in the future, even if the mangled name does not, you should
+check that all of your version directives are behaving as you expect
+when you upgrade.
+
+3.10 Expressions in Linker Scripts
+==================================
+
+The syntax for expressions in the linker script language is identical to
+that of C expressions. All expressions are evaluated as integers. All
+expressions are evaluated in the same size, which is 32 bits if both the
+host and target are 32 bits, and is otherwise 64 bits.
+
+ You can use and set symbol values in expressions.
+
+ The linker defines several special purpose builtin functions for use
+in expressions.
+
+3.10.1 Constants
+----------------
+
+All constants are integers.
+
+ As in C, the linker considers an integer beginning with '0' to be
+octal, and an integer beginning with '0x' or '0X' to be hexadecimal.
+The linker considers other integers to be decimal.
+
+ In addition, you can use the suffixes 'K' and 'M' to scale a constant
+by '1024' or '1024*1024' respectively. For example, the following all
+refer to the same quantity:
+ _fourk_1 = 4K;
+ _fourk_2 = 4096;
+ _fourk_3 = 0x1000;
+
+3.10.2 Symbol Names
+-------------------
+
+Unless quoted, symbol names start with a letter, underscore, or period
+and may include letters, digits, underscores, periods, and hyphens.
+Unquoted symbol names must not conflict with any keywords. You can
+specify a symbol which contains odd characters or has the same name as a
+keyword by surrounding the symbol name in double quotes:
+ "SECTION" = 9;
+ "with a space" = "also with a space" + 10;
+
+ Since symbols can contain many non-alphabetic characters, it is
+safest to delimit symbols with spaces. For example, 'A-B' is one
+symbol, whereas 'A - B' is an expression involving subtraction.
+
+3.10.3 Orphan Sections
+----------------------
+
+Orphan sections are sections present in the input files which are not
+explicitly placed into the output file by the linker script. The linker
+will still copy these sections into the output file, but it has to guess
+as to where they should be placed. The linker uses a simple heuristic
+to do this. It attempts to place orphan sections after non-orphan
+sections of the same attribute, such as code vs data, loadable vs
+non-loadable, etc. If there is not enough room to do this then it
+places at the end of the file.
+
+ For ELF targets, the attribute of the section includes section type
+as well as section flag.
+
+3.10.4 The Location Counter
+---------------------------
+
+The special linker variable "dot" '.' always contains the current output
+location counter. Since the '.' always refers to a location in an
+output section, it may only appear in an expression within a 'SECTIONS'
+command. The '.' symbol may appear anywhere that an ordinary symbol is
+allowed in an expression.
+
+ Assigning a value to '.' will cause the location counter to be moved.
+This may be used to create holes in the output section. The location
+counter may not be moved backwards inside an output section, and may not
+be moved backwards outside of an output section if so doing creates
+areas with overlapping LMAs.
+
+ SECTIONS
+ {
+ output :
+ {
+ file1(.text)
+ . = . + 1000;
+ file2(.text)
+ . += 1000;
+ file3(.text)
+ } = 0x12345678;
+ }
+In the previous example, the '.text' section from 'file1' is located at
+the beginning of the output section 'output'. It is followed by a 1000
+byte gap. Then the '.text' section from 'file2' appears, also with a
+1000 byte gap following before the '.text' section from 'file3'. The
+notation '= 0x12345678' specifies what data to write in the gaps (*note
+Output Section Fill::).
+
+ Note: '.' actually refers to the byte offset from the start of the
+current containing object. Normally this is the 'SECTIONS' statement,
+whose start address is 0, hence '.' can be used as an absolute address.
+If '.' 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:
+
+ SECTIONS
+ {
+ . = 0x100
+ .text: {
+ *(.text)
+ . = 0x200
+ }
+ . = 0x500
+ .data: {
+ *(.data)
+ . += 0x600
+ }
+ }
+
+ The '.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
+'.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 '.'
+backwards). The '.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
+'.data' input sections and before the end of the '.data' output section
+itself.
+
+ Setting symbols to the value of the location counter outside of an
+output section statement can result in unexpected values if the linker
+needs to place orphan sections. For example, given the following:
+
+ SECTIONS
+ {
+ start_of_text = . ;
+ .text: { *(.text) }
+ end_of_text = . ;
+
+ start_of_data = . ;
+ .data: { *(.data) }
+ end_of_data = . ;
+ }
+
+ If the linker needs to place some input section, e.g. '.rodata', not
+mentioned in the script, it might choose to place that section between
+'.text' and '.data'. You might think the linker should place '.rodata'
+on the blank line in the above script, but blank lines are of no
+particular significance to the linker. As well, the linker doesn't
+associate the above symbol names with their sections. Instead, it
+assumes that all assignments or other statements belong to the previous
+output section, except for the special case of an assignment to '.'.
+I.e., the linker will place the orphan '.rodata' section as if the
+script was written as follows:
+
+ SECTIONS
+ {
+ start_of_text = . ;
+ .text: { *(.text) }
+ end_of_text = . ;
+
+ start_of_data = . ;
+ .rodata: { *(.rodata) }
+ .data: { *(.data) }
+ end_of_data = . ;
+ }
+
+ This may or may not be the script author's intention for the value of
+'start_of_data'. One way to influence the orphan section placement is
+to assign the location counter to itself, as the linker assumes that an
+assignment to '.' is setting the start address of a following output
+section and thus should be grouped with that section. So you could
+write:
+
+ SECTIONS
+ {
+ start_of_text = . ;
+ .text: { *(.text) }
+ end_of_text = . ;
+
+ . = . ;
+ start_of_data = . ;
+ .data: { *(.data) }
+ end_of_data = . ;
+ }
+
+ Now, the orphan '.rodata' section will be placed between
+'end_of_text' and 'start_of_data'.
+
+3.10.5 Operators
+----------------
+
+The linker recognizes the standard C set of arithmetic operators, with
+the standard bindings and precedence levels:
+ precedence associativity Operators Notes
+ (highest)
+ 1 left ! - ~ (1)
+ 2 left * / %
+ 3 left + -
+ 4 left >> <<
+ 5 left == != > < <= >=
+ 6 left &
+ 7 left |
+ 8 left &&
+ 9 left ||
+ 10 right ? :
+ 11 right &= += -= *= /= (2)
+ (lowest)
+ Notes: (1) Prefix operators (2) *Note Assignments::.
+
+3.10.6 Evaluation
+-----------------
+
+The linker evaluates expressions lazily. It only computes the value of
+an expression when absolutely necessary.
+
+ The linker needs some information, such as the value of the start
+address of the first section, and the origins and lengths of memory
+regions, in order to do any linking at all. These values are computed
+as soon as possible when the linker reads in the linker script.
+
+ However, other values (such as symbol values) are not known or needed
+until after storage allocation. Such values are evaluated later, when
+other information (such as the sizes of output sections) is available
+for use in the symbol assignment expression.
+
+ The sizes of sections cannot be known until after allocation, so
+assignments dependent upon these are not performed until after
+allocation.
+
+ Some expressions, such as those depending upon the location counter
+'.', must be evaluated during section allocation.
+
+ If the result of an expression is required, but the value is not
+available, then an error results. For example, a script like the
+following
+ SECTIONS
+ {
+ .text 9+this_isnt_constant :
+ { *(.text) }
+ }
+will cause the error message 'non constant expression for initial
+address'.
+
+3.10.7 The Section of an Expression
+-----------------------------------
+
+When the linker evaluates an expression, the result is either absolute
+or relative to some section. A relative expression is expressed as a
+fixed offset from the base of a section.
+
+ The position of the expression within the linker script determines
+whether it is absolute or relative. An expression which appears within
+an output section definition is relative to the base of the output
+section. An expression which appears elsewhere will be absolute.
+
+ A symbol set to a relative expression will be relocatable if you
+request relocatable output using the '-r' option. That means that a
+further link operation may change the value of the symbol. The symbol's
+section will be the section of the relative expression.
+
+ A symbol set to an absolute expression will retain the same value
+through any further link operation. The symbol will be absolute, and
+will not have any particular associated section.
+
+ You can use the builtin function 'ABSOLUTE' to force an expression to
+be absolute when it would otherwise be relative. For example, to create
+an absolute symbol set to the address of the end of the output section
+'.data':
+ SECTIONS
+ {
+ .data : { *(.data) _edata = ABSOLUTE(.); }
+ }
+If 'ABSOLUTE' were not used, '_edata' would be relative to the '.data'
+section.
+
+3.10.8 Builtin Functions
+------------------------
+
+The linker script language includes a number of builtin functions for
+use in linker script expressions.
+
+'ABSOLUTE(EXP)'
+ Return the absolute (non-relocatable, as opposed to non-negative)
+ value of the expression EXP. Primarily useful to assign an
+ absolute value to a symbol within a section definition, where
+ symbol values are normally section relative. *Note Expression
+ Section::.
+
+'ADDR(SECTION)'
+ Return the absolute address (the VMA) of the named SECTION. Your
+ script must previously have defined the location of that section.
+ In the following example, 'symbol_1' and 'symbol_2' are assigned
+ identical values:
+ SECTIONS { ...
+ .output1 :
+ {
+ start_of_output_1 = ABSOLUTE(.);
+ ...
+ }
+ .output :
+ {
+ symbol_1 = ADDR(.output1);
+ symbol_2 = start_of_output_1;
+ }
+ ... }
+
+'ALIGN(ALIGN)'
+'ALIGN(EXP,ALIGN)'
+ Return the location counter ('.') or arbitrary expression aligned
+ to the next ALIGN boundary. The single operand 'ALIGN' doesn't
+ change the value of the location counter--it just does arithmetic
+ on it. The two operand 'ALIGN' allows an arbitrary expression to
+ be aligned upwards ('ALIGN(ALIGN)' is equivalent to 'ALIGN(.,
+ ALIGN)').
+
+ Here is an example which aligns the output '.data' section to the
+ next '0x2000' byte boundary after the preceding section and sets a
+ variable within the section to the next '0x8000' boundary after the
+ input sections:
+ SECTIONS { ...
+ .data ALIGN(0x2000): {
+ *(.data)
+ variable = ALIGN(0x8000);
+ }
+ ... }
+ The first use of 'ALIGN' in this example specifies the location of
+ a section because it is used as the optional ADDRESS attribute of a
+ section definition (*note Output Section Address::). The second
+ use of 'ALIGN' is used to defines the value of a symbol.
+
+ The builtin function 'NEXT' is closely related to 'ALIGN'.
+
+'ALIGNOF(SECTION)'
+ Return the alignment in bytes of the named SECTION, if that section
+ has been allocated. If the section has not been allocated when
+ this is evaluated, the linker will report an error. In the
+ following example, the alignment of the '.output' section is stored
+ as the first value in that section.
+ SECTIONS{ ...
+ .output {
+ LONG (ALIGNOF (.output))
+ ...
+ }
+ ... }
+
+'BLOCK(EXP)'
+ This is a synonym for 'ALIGN', for compatibility with older linker
+ scripts. It is most often seen when setting the address of an
+ output section.
+
+'DATA_SEGMENT_ALIGN(MAXPAGESIZE, COMMONPAGESIZE)'
+ This is equivalent to either
+ (ALIGN(MAXPAGESIZE) + (. & (MAXPAGESIZE - 1)))
+ or
+ (ALIGN(MAXPAGESIZE) + (. & (MAXPAGESIZE - COMMONPAGESIZE)))
+ depending on whether the latter uses fewer COMMONPAGESIZE sized
+ pages for the data segment (area between the result of this
+ expression and 'DATA_SEGMENT_END') than the former or not. If the
+ latter form is used, it means COMMONPAGESIZE bytes of runtime
+ memory will be saved at the expense of up to COMMONPAGESIZE wasted
+ bytes in the on-disk file.
+
+ This expression can only be used directly in 'SECTIONS' commands,
+ not in any output section descriptions and only once in the linker
+ script. COMMONPAGESIZE should be less or equal to MAXPAGESIZE and
+ should be the system page size the object wants to be optimized for
+ (while still working on system page sizes up to MAXPAGESIZE).
+
+ Example:
+ . = DATA_SEGMENT_ALIGN(0x10000, 0x2000);
+
+'DATA_SEGMENT_END(EXP)'
+ This defines the end of data segment for 'DATA_SEGMENT_ALIGN'
+ evaluation purposes.
+
+ . = DATA_SEGMENT_END(.);
+
+'DATA_SEGMENT_RELRO_END(OFFSET, EXP)'
+ This defines the end of the 'PT_GNU_RELRO' segment when '-z relro'
+ option is used. Second argument is returned. When '-z relro'
+ option is not present, 'DATA_SEGMENT_RELRO_END' does nothing,
+ otherwise 'DATA_SEGMENT_ALIGN' is padded so that EXP + OFFSET is
+ aligned to the most commonly used page boundary for particular
+ target. If present in the linker script, it must always come in
+ between 'DATA_SEGMENT_ALIGN' and 'DATA_SEGMENT_END'.
+
+ . = DATA_SEGMENT_RELRO_END(24, .);
+
+'DEFINED(SYMBOL)'
+ Return 1 if SYMBOL is in the linker global symbol table and is
+ defined before the statement using DEFINED in the script, otherwise
+ return 0. You can use this function to provide default values for
+ symbols. For example, the following script fragment shows how to
+ set a global symbol 'begin' to the first location in the '.text'
+ section--but if a symbol called 'begin' already existed, its value
+ is preserved:
+
+ SECTIONS { ...
+ .text : {
+ begin = DEFINED(begin) ? begin : . ;
+ ...
+ }
+ ...
+ }
+
+'LENGTH(MEMORY)'
+ Return the length of the memory region named MEMORY.
+
+'LOADADDR(SECTION)'
+ Return the absolute LMA of the named SECTION. This is normally the
+ same as 'ADDR', but it may be different if the 'AT' attribute is
+ used in the output section definition (*note Output Section LMA::).
+
+'MAX(EXP1, EXP2)'
+ Returns the maximum of EXP1 and EXP2.
+
+'MIN(EXP1, EXP2)'
+ Returns the minimum of EXP1 and EXP2.
+
+'NEXT(EXP)'
+ Return the next unallocated address that is a multiple of EXP.
+ This function is closely related to 'ALIGN(EXP)'; unless you use
+ the 'MEMORY' command to define discontinuous memory for the output
+ file, the two functions are equivalent.
+
+'ORIGIN(MEMORY)'
+ Return the origin of the memory region named MEMORY.
+
+'SEGMENT_START(SEGMENT, DEFAULT)'
+ Return the base address of the named SEGMENT. If an explicit value
+ has been given for this segment (with a command-line '-T' option)
+ that value will be returned; otherwise the value will be DEFAULT.
+ At present, the '-T' command-line option can only be used to set
+ the base address for the "text", "data", and "bss" sections, but
+ you use 'SEGMENT_START' with any segment name.
+
+'SIZEOF(SECTION)'
+ Return the size in bytes of the named SECTION, if that section has
+ been allocated. If the section has not been allocated when this is
+ evaluated, the linker will report an error. In the following
+ example, 'symbol_1' and 'symbol_2' are assigned identical values:
+ SECTIONS{ ...
+ .output {
+ .start = . ;
+ ...
+ .end = . ;
+ }
+ symbol_1 = .end - .start ;
+ symbol_2 = SIZEOF(.output);
+ ... }
+
+'SIZEOF_HEADERS'
+'sizeof_headers'
+ Return the size in bytes of the output file's headers. This is
+ information which appears at the start of the output file. You can
+ use this number when setting the start address of the first
+ section, if you choose, to facilitate paging.
+
+ When producing an ELF output file, if the linker script uses the
+ 'SIZEOF_HEADERS' builtin function, the linker must compute the
+ number of program headers before it has determined all the section
+ addresses and sizes. If the linker later discovers that it needs
+ additional program headers, it will report an error 'not enough
+ room for program headers'. To avoid this error, you must avoid
+ using the 'SIZEOF_HEADERS' function, or you must rework your linker
+ script to avoid forcing the linker to use additional program
+ headers, or you must define the program headers yourself using the
+ 'PHDRS' command (*note PHDRS::).
+
+3.11 Implicit Linker Scripts
+============================
+
+If you specify a linker input file which the linker can not recognize as
+an object file or an archive file, it will try to read the file as a
+linker script. If the file can not be parsed as a linker script, the
+linker will report an error.
+
+ An implicit linker script will not replace the default linker script.
+
+ Typically an implicit linker script would contain only symbol
+assignments, or the 'INPUT', 'GROUP', or 'VERSION' commands.
+
+ Any input files read because of an implicit linker script will be
+read at the position in the command line where the implicit linker
+script was read. This can affect archive searching.
+
+4 Machine Dependent Features
+****************************
+
+'ld' has additional features on some platforms; the following sections
+describe them. Machines where 'ld' has no additional functionality are
+not listed.
+
+4.1 'ld' and the H8/300
+=======================
+
+For the H8/300, 'ld' can perform these global optimizations when you
+specify the '--relax' command-line option.
+
+_relaxing address modes_
+ 'ld' finds all 'jsr' and 'jmp' instructions whose targets are
+ within eight bits, and turns them into eight-bit program-counter
+ relative 'bsr' and 'bra' instructions, respectively.
+
+_synthesizing instructions_
+ 'ld' finds all '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 'mov.b '@'AA:16' into 'mov.b '@'AA:8' whenever the
+ address AA is in the top page of memory).
+
+_bit manipulation instructions_
+ 'ld' finds all bit manipulation instructions like 'band, bclr,
+ biand, bild, bior, bist, bixor, bld, bnot, bor, bset, bst, btst,
+ bxor' which use 32 bit and 16 bit absolute address form, but refer
+ to the top page of memory, and changes them to use the 8 bit
+ address form. (That is: the linker turns 'bset #xx:3,'@'AA:32'
+ into 'bset #xx:3,'@'AA:8' whenever the address AA is in the top
+ page of memory).
+
+_system control instructions_
+ 'ld' finds all 'ldc.w, stc.w' instructions which use the 32 bit
+ absolute address form, but refer to the top page of memory, and
+ changes them to use 16 bit address form. (That is: the linker
+ turns 'ldc.w '@'AA:32,ccr' into 'ldc.w '@'AA:16,ccr' whenever the
+ address AA is in the top page of memory).
+
+4.2 'ld' and the Intel 960 Family
+=================================
+
+You can use the '-AARCHITECTURE' command line option to specify one of
+the two-letter names identifying members of the 960 family; the option
+specifies the desired output target, and warns of any incompatible
+instructions in the input files. It also modifies the linker's search
+strategy for archive libraries, to support the use of libraries specific
+to each particular architecture, by including in the search loop names
+suffixed with the string identifying the architecture.
+
+ For example, if your 'ld' command line included '-ACA' as well as
+'-ltry', the linker would look (in its built-in search paths, and in any
+paths you specify with '-L') for a library with the names
+
+ try
+ libtry.a
+ tryca
+ libtryca.a
+
+The first two possibilities would be considered in any event; the last
+two are due to the use of '-ACA'.
+
+ You can meaningfully use '-A' more than once on a command line, since
+the 960 architecture family allows combination of target architectures;
+each use will add another pair of name variants to search for when '-l'
+specifies a library.
+
+ 'ld' supports the '--relax' option for the i960 family. If you
+specify '--relax', 'ld' finds all 'balx' and 'calx' instructions whose
+targets are within 24 bits, and turns them into 24-bit program-counter
+relative 'bal' and 'cal' instructions, respectively. 'ld' also turns
+'cal' instructions into 'bal' instructions when it determines that the
+target subroutine is a leaf routine (that is, the target subroutine does
+not itself call any subroutines).
+
+4.3 'ld' and the Motorola 68HC11 and 68HC12 families
+====================================================
+
+4.3.1 Linker Relaxation
+-----------------------
+
+For the Motorola 68HC11, 'ld' can perform these global optimizations
+when you specify the '--relax' command-line option.
+
+_relaxing address modes_
+ 'ld' finds all 'jsr' and 'jmp' instructions whose targets are
+ within eight bits, and turns them into eight-bit program-counter
+ relative 'bsr' and 'bra' instructions, respectively.
+
+ 'ld' also looks at all 16-bit extended addressing modes and
+ transforms them in a direct addressing mode when the address is in
+ page 0 (between 0 and 0x0ff).
+
+_relaxing gcc instruction group_
+ When 'gcc' is called with '-mrelax', it can emit group of
+ instructions that the linker can optimize to use a 68HC11 direct
+ addressing mode. These instructions consists of 'bclr' or 'bset'
+ instructions.
+
+4.3.2 Trampoline Generation
+---------------------------
+
+For 68HC11 and 68HC12, 'ld' can generate trampoline code to call a far
+function using a normal 'jsr' instruction. The linker will also change
+the relocation to some far function to use the trampoline address
+instead of the function address. This is typically the case when a
+pointer to a function is taken. The pointer will in fact point to the
+function trampoline.
+
+ The '--pic-veneer' switch makes the linker use PIC sequences for
+ARM/Thumb interworking veneers, even if the rest of the binary is not
+PIC. This avoids problems on uClinux targets where '--emit-relocs' is
+used to generate relocatable binaries.
+
+4.4 'ld' and the ARM family
+===========================
+
+For the ARM, 'ld' will generate code stubs to allow functions calls
+between ARM and Thumb code. These stubs only work with code that has
+been compiled and assembled with the '-mthumb-interwork' command line
+option. If it is necessary to link with old ARM object files or
+libraries, which have not been compiled with the -mthumb-interwork
+option then the '--support-old-code' command line switch should be given
+to the linker. This will make it generate larger stub functions which
+will work with non-interworking aware ARM code. Note, however, the
+linker does not support generating stubs for function calls to
+non-interworking aware Thumb code.
+
+ The '--thumb-entry' switch is a duplicate of the generic '--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.
+
+ The '--be8' switch instructs 'ld' to generate BE8 format executables.
+This option is only valid when linking big-endian objects. The
+resulting image will contain big-endian data and little-endian code.
+
+ The 'R_ARM_TARGET1' relocation is typically used for entries in the
+'.init_array' section. It is interpreted as either 'R_ARM_REL32' or
+'R_ARM_ABS32', depending on the target. The '--target1-rel' and
+'--target1-abs' switches override the default.
+
+ The '--target2=type' switch overrides the default definition of the
+'R_ARM_TARGET2' relocation. Valid values for 'type', their meanings,
+and target defaults are as follows:
+'rel'
+ 'R_ARM_REL32' (arm*-*-elf, arm*-*-eabi)
+'abs'
+ 'R_ARM_ABS32' (arm*-*-symbianelf)
+'got-rel'
+ 'R_ARM_GOT_PREL' (arm*-*-linux, arm*-*-*bsd)
+
+ The 'R_ARM_V4BX' relocation (defined by the ARM AAELF specification)
+enables objects compiled for the ARMv4 architecture to be
+interworking-safe when linked with other objects compiled for ARMv4t,
+but also allows pure ARMv4 binaries to be built from the same ARMv4
+objects.
+
+ In the latter case, the switch '--fix-v4bx' must be passed to the
+linker, which causes v4t 'BX rM' instructions to be rewritten as 'MOV
+PC,rM', since v4 processors do not have a 'BX' instruction.
+
+ In the former case, the switch should not be used, and 'R_ARM_V4BX'
+relocations are ignored.
+
+ The '--use-blx' switch enables the linker to use ARM/Thumb BLX
+instructions (available on ARMv5t and above) in various situations.
+Currently it is used to perform calls via the PLT from Thumb code using
+BLX rather than using BX and a mode-switching stub before each PLT
+entry. This should lead to such calls executing slightly faster.
+
+ This option is enabled implicitly for SymbianOS, so there is no need
+to specify it if you are using that target.
+
+ The '--vfp11-denorm-fix' switch enables a link-time workaround for a
+bug in certain VFP11 coprocessor hardware, which sometimes allows
+instructions with denorm operands (which must be handled by support
+code) to have those operands overwritten by subsequent instructions
+before the support code can read the intended values.
+
+ The bug may be avoided in scalar mode if you allow at least one
+intervening instruction between a VFP11 instruction which uses a
+register and another instruction which writes to the same register, or
+at least two intervening instructions if vector mode is in use. The bug
+only affects full-compliance floating-point mode: you do not need this
+workaround if you are using "runfast" mode. Please contact ARM for
+further details.
+
+ If you know you are using buggy VFP11 hardware, you can enable this
+workaround by specifying the linker option '--vfp-denorm-fix=scalar' if
+you are using the VFP11 scalar mode only, or '--vfp-denorm-fix=vector'
+if you are using vector mode (the latter also works for scalar code).
+The default is '--vfp-denorm-fix=none'.
+
+ If the workaround is enabled, instructions are scanned for
+potentially-troublesome sequences, and a veneer is created for each such
+sequence which may trigger the erratum. The veneer consists of the
+first instruction of the sequence and a branch back to the subsequent
+instruction. The original instruction is then replaced with a branch to
+the veneer. The extra cycles required to call and return from the
+veneer are sufficient to avoid the erratum in both the scalar and vector
+cases.
+
+ The '--no-enum-size-warning' switch prevents the linker from warning
+when linking object files that specify incompatible EABI enumeration
+size attributes. For example, with this switch enabled, linking of an
+object file using 32-bit enumeration values with another using
+enumeration values fitted into the smallest possible space will not be
+diagnosed.
+
+4.5 'ld' and HPPA 32-bit ELF Support
+====================================
+
+When generating a shared library, 'ld' will by default generate import
+stubs suitable for use with a single sub-space application. The
+'--multi-subspace' switch causes 'ld' to generate export stubs, and
+different (larger) import stubs suitable for use with multiple
+sub-spaces.
+
+ Long branch stubs and import/export stubs are placed by 'ld' in stub
+sections located between groups of input sections. '--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 'N' chooses
+this scheme, ensuring that branches to stubs always use a negative
+offset. Two special values of 'N' are recognized, '1' and '-1'. These
+both instruct '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 'N' respectively.
+
+ Note that '--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.
+
+4.6 'ld' and MMIX
+=================
+
+For MMIX, there is a choice of generating 'ELF' object files or 'mmo'
+object files when linking. The simulator 'mmix' understands the 'mmo'
+format. The binutils 'objcopy' utility can translate between the two
+formats.
+
+ There is one special section, the '.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
+'.MMIX.reg_contents' section corresponds to the first allocated global
+register multiplied by 8. Register '$255' is not included in this
+section; it is always set to the program entry, which is at the symbol
+'Main' for 'mmo' files.
+
+ Symbols with the prefix '__.MMIX.start.', for example
+'__.MMIX.start..text' and '__.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.
+
+4.7 'ld' and MSP430
+===================
+
+For the MSP430 it is possible to select the MPU architecture. The flag
+'-m [mpu type]' will select an appropriate linker script for selected
+MPU type. (To get a list of known MPUs just pass '-m help' option to
+the linker).
+
+ The linker will recognize some extra sections which are MSP430
+specific:
+
+''.vectors''
+ Defines a portion of ROM where interrupt vectors located.
+
+''.bootloader''
+ Defines the bootloader portion of the ROM (if applicable). Any
+ code in this section will be uploaded to the MPU.
+
+''.infomem''
+ Defines an information memory section (if applicable). Any code in
+ this section will be uploaded to the MPU.
+
+''.infomemnobits''
+ This is the same as the '.infomem' section except that any code in
+ this section will not be uploaded to the MPU.
+
+''.noinit''
+ Denotes a portion of RAM located above '.bss' section.
+
+ The last two sections are used by gcc.
+
+4.8 'ld' and PowerPC 32-bit ELF Support
+=======================================
+
+Branches on PowerPC processors are limited to a signed 26-bit
+displacement, which may result in 'ld' giving 'relocation truncated to
+fit' errors with very large programs. '--relax' enables the generation
+of trampolines that can access the entire 32-bit address space. These
+trampolines are inserted at section boundaries, so may not themselves be
+reachable if an input section exceeds 33M in size.
+
+'--bss-plt'
+ Current PowerPC GCC accepts a '-msecure-plt' option that generates
+ code capable of using a newer PLT and GOT layout that has the
+ security advantage of no executable section ever needing to be
+ writable and no writable section ever being executable. PowerPC
+ 'ld' will generate this layout, including stubs to access the PLT,
+ if all input files (including startup and static libraries) were
+ compiled with '-msecure-plt'. '--bss-plt' forces the old BSS PLT
+ (and GOT layout) which can give slightly better performance.
+
+'--secure-plt'
+ 'ld' will use the new PLT and GOT layout if it is linking new
+ '-fpic' or '-fPIC' code, but does not do so automatically when
+ linking non-PIC code. This option requests the new PLT and GOT
+ layout. A warning will be given if some object file requires the
+ old style BSS PLT.
+
+'--sdata-got'
+ The new secure PLT and GOT are placed differently relative to other
+ sections compared to older BSS PLT and GOT placement. The location
+ of '.plt' must change because the new secure PLT is an initialized
+ section while the old PLT is uninitialized. The reason for the
+ '.got' change is more subtle: The new placement allows '.got' to be
+ read-only in applications linked with '-z relro -z now'. However,
+ this placement means that '.sdata' cannot always be used in shared
+ libraries, because the PowerPC ABI accesses '.sdata' in shared
+ libraries from the GOT pointer. '--sdata-got' forces the old GOT
+ placement. PowerPC GCC doesn't use '.sdata' in shared libraries,
+ so this option is really only useful for other compilers that may
+ do so.
+
+'--emit-stub-syms'
+ This option causes 'ld' to label linker stubs with a local symbol
+ that encodes the stub type and destination.
+
+'--no-tls-optimize'
+ PowerPC 'ld' normally performs some optimization of code sequences
+ used to access Thread-Local Storage. Use this option to disable
+ the optimization.
+
+4.9 'ld' and PowerPC64 64-bit ELF Support
+=========================================
+
+'--stub-group-size'
+ Long branch stubs, PLT call stubs and TOC adjusting stubs are
+ placed by 'ld' in stub sections located between groups of input
+ sections. '--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 'N'
+ chooses this scheme, ensuring that branches to stubs always use a
+ negative offset. Two special values of 'N' are recognized, '1' and
+ '-1'. These both instruct '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
+ 'N' respectively.
+
+ Note that '--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.
+
+'--emit-stub-syms'
+ This option causes 'ld' to label linker stubs with a local symbol
+ that encodes the stub type and destination.
+
+'--dotsyms, --no-dotsyms'
+ These two options control how 'ld' interprets version patterns in a
+ version script. Older PowerPC64 compilers emitted both a function
+ descriptor symbol with the same name as the function, and a code
+ entry symbol with the name prefixed by a dot ('.'). To properly
+ version a function 'foo', the version script thus needs to control
+ both 'foo' and '.foo'. The option '--dotsyms', on by default,
+ automatically adds the required dot-prefixed patterns. Use
+ '--no-dotsyms' to disable this feature.
+
+'--no-tls-optimize'
+ PowerPC64 'ld' normally performs some optimization of code
+ sequences used to access Thread-Local Storage. Use this option to
+ disable the optimization.
+
+'--no-opd-optimize'
+ PowerPC64 'ld' normally removes '.opd' section entries
+ corresponding to deleted link-once functions, or functions removed
+ by the action of '--gc-sections' or linker scrip '/DISCARD/'. Use
+ this option to disable '.opd' optimization.
+
+'--non-overlapping-opd'
+ Some PowerPC64 compilers have an option to generate compressed
+ '.opd' entries spaced 16 bytes apart, overlapping the third word,
+ the static chain pointer (unused in C) with the first word of the
+ next entry. This option expands such entries to the full 24 bytes.
+
+'--no-toc-optimize'
+ PowerPC64 'ld' normally removes unused '.toc' section entries.
+ Such entries are detected by examining relocations that reference
+ the TOC in code sections. A reloc in a deleted code section marks
+ a TOC word as unneeded, while a reloc in a kept code section marks
+ a TOC word as needed. Since the TOC may reference itself, TOC
+ relocs are also examined. TOC words marked as both needed and
+ unneeded will of course be kept. TOC words without any referencing
+ reloc are assumed to be part of a multi-word entry, and are kept or
+ discarded as per the nearest marked preceding word. This works
+ reliably for compiler generated code, but may be incorrect if
+ assembly code is used to insert TOC entries. Use this option to
+ disable the optimization.
+
+'--no-multi-toc'
+ By default, PowerPC64 GCC generates code for a TOC model where TOC
+ entries are accessed with a 16-bit offset from r2. This limits the
+ total TOC size to 64K. PowerPC64 'ld' extends this limit by
+ grouping code sections such that each group uses less than 64K for
+ its TOC entries, then inserts r2 adjusting stubs between
+ inter-group calls. 'ld' does not split apart input sections, so
+ cannot help if a single input file has a '.toc' section that
+ exceeds 64K, most likely from linking multiple files with 'ld -r'.
+ Use this option to turn off this feature.
+
+4.10 'ld' and SPU ELF Support
+=============================
+
+'--plugin'
+ This option marks an executable as a PIC plugin module.
+
+'--no-overlays'
+ Normally, 'ld' recognizes calls to functions within overlay
+ regions, and redirects such calls to an overlay manager via a stub.
+ 'ld' also provides a built-in overlay manager. This option turns
+ off all this special overlay handling.
+
+'--emit-stub-syms'
+ This option causes 'ld' to label overlay stubs with a local symbol
+ that encodes the stub type and destination.
+
+'--extra-overlay-stubs'
+ This option causes 'ld' to add overlay call stubs on all function
+ calls out of overlay regions. Normally stubs are not added on
+ calls to non-overlay regions.
+
+'--local-store=lo:hi'
+ 'ld' usually checks that a final executable for SPU fits in the
+ address range 0 to 256k. This option may be used to change the
+ range. Disable the check entirely with '--local-store=0:0'.
+
+'--stack-analysis'
+ SPU local store space is limited. Over-allocation of stack space
+ unnecessarily limits space available for code and data, while
+ under-allocation results in runtime failures. If given this
+ option, 'ld' will provide an estimate of maximum stack usage. 'ld'
+ does this by examining symbols in code sections to determine the
+ extents of functions, and looking at function prologues for stack
+ adjusting instructions. A call-graph is created by looking for
+ relocations on branch instructions. The graph is then searched for
+ the maximum stack usage path. Note that this analysis does not
+ find calls made via function pointers, and does not handle
+ recursion and other cycles in the call graph. Stack usage may be
+ under-estimated if your code makes such calls. Also, stack usage
+ for dynamic allocation, e.g. alloca, will not be detected. If a
+ link map is requested, detailed information about each function's
+ stack usage and calls will be given.
+
+'--emit-stack-syms'
+ This option, if given along with '--stack-analysis' will result in
+ 'ld' emitting stack sizing symbols for each function. These take
+ the form '__stack_<function_name>' for global functions, and
+ '__stack_<number>_<function_name>' for static functions.
+ '<number>' is the section id in hex. The value of such symbols is
+ the stack requirement for the corresponding function. The symbol
+ size will be zero, type 'STT_NOTYPE', binding 'STB_LOCAL', and
+ section 'SHN_ABS'.
+
+4.11 'ld''s Support for Various TI COFF Versions
+================================================
+
+The '--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;
+'ld' will read any version or byte order, but the output header format
+depends on the default specified by the specific target.
+
+4.12 'ld' and WIN32 (cygwin/mingw)
+==================================
+
+This section describes some of the win32 specific 'ld' issues. See
+*note Command Line Options: Options. for detailed description of the
+command line options mentioned here.
+
+_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 'ld' have specific support
+ for creating such libraries provided with the '--out-implib'
+ command line option.
+
+_exporting DLL symbols_
+ The cygwin/mingw 'ld' has several ways to export symbols for dll's.
+
+ _using auto-export functionality_
+ By default 'ld' exports symbols with the auto-export
+ functionality, which is controlled by the following command
+ line options:
+
+ * -export-all-symbols [This is the default]
+ * -exclude-symbols
+ * -exclude-libs
+
+ If, however, '--export-all-symbols' is not given explicitly on
+ the command line, then the default auto-export behavior will
+ be _disabled_ if either of the following are true:
+
+ * A DEF file is used.
+ * Any symbol in any object file was marked with the
+ __declspec(dllexport) attribute.
+
+ _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
+ '<dll name>.def' and is added as any other object file to the
+ linker's command line. The file's name must end in '.def' or
+ '.DEF'.
+
+ gcc -o <output> <objectfiles> <dll name>.def
+
+ Using a DEF file turns off the normal auto-export behavior,
+ unless the '--export-all-symbols' option is also used.
+
+ Here is an example of a DEF file for a shared library called
+ 'xyz.dll':
+
+ LIBRARY "xyz.dll" BASE=0x20000000
+
+ EXPORTS
+ foo
+ bar
+ _bar = bar
+ another_foo = abc.dll.afoo
+ var1 DATA
+
+ This example defines a DLL with a non-default base address and
+ five symbols in the export table. The third exported symbol
+ '_bar' is an alias for the second. The fourth symbol,
+ 'another_foo' is resolved by "forwarding" to another module
+ and treating it as an alias for 'afoo' exported from the DLL
+ 'abc.dll'. The final symbol 'var1' is declared to be a data
+ object.
+
+ The optional 'LIBRARY <name>' command indicates the _internal_
+ name of the output DLL. If '<name>' does not include a suffix,
+ the default library suffix, '.DLL' is appended.
+
+ When the .DEF file is used to build an application, rather
+ than a library, the 'NAME <name>' command should be used
+ instead of 'LIBRARY'. If '<name>' does not include a suffix,
+ the default executable suffix, '.EXE' is appended.
+
+ With either 'LIBRARY <name>' or 'NAME <name>' the optional
+ specification 'BASE = <number>' may be used to specify a
+ non-default base address for the image.
+
+ If neither 'LIBRARY <name>' nor 'NAME <name>' is specified, or
+ they specify an empty string, the internal name is the same as
+ the filename specified on the command line.
+
+ The complete specification of an export symbol is:
+
+ EXPORTS
+ ( ( ( <name1> [ = <name2> ] )
+ | ( <name1> = <module-name> . <external-name>))
+ [ @ <integer> ] [NONAME] [DATA] [CONSTANT] [PRIVATE] ) *
+
+ Declares '<name1>' as an exported symbol from the DLL, or
+ declares '<name1>' as an exported alias for '<name2>'; or
+ declares '<name1>' as a "forward" alias for the symbol
+ '<external-name>' in the DLL '<module-name>'. Optionally, the
+ symbol may be exported by the specified ordinal '<integer>'
+ alias.
+
+ The optional keywords that follow the declaration indicate:
+
+ 'NONAME': Do not put the symbol name in the DLL's export
+ table. It will still be exported by its ordinal alias (either
+ the value specified by the .def specification or, otherwise,
+ the value assigned by the linker). The symbol name, however,
+ does remain visible in the import library (if any), unless
+ 'PRIVATE' is also specified.
+
+ 'DATA': The symbol is a variable or object, rather than a
+ function. The import lib will export only an indirect
+ reference to 'foo' as the symbol '_imp__foo' (ie, 'foo' must
+ be resolved as '*_imp__foo').
+
+ 'CONSTANT': Like 'DATA', but put the undecorated 'foo' as well
+ as '_imp__foo' into the import library. Both refer to the
+ read-only import address table's pointer to the variable, not
+ to the variable itself. This can be dangerous. If the user
+ code fails to add the 'dllimport' attribute and also fails to
+ explicitly add the extra indirection that the use of the
+ attribute enforces, the application will behave unexpectedly.
+
+ 'PRIVATE': Put the symbol in the DLL's export table, but do
+ not put it into the static import library used to resolve
+ imports at link time. The symbol can still be imported using
+ the 'LoadLibrary/GetProcAddress' API at runtime or by by using
+ the GNU ld extension of linking directly to the DLL without an
+ import library.
+
+ See ld/deffilep.y in the binutils sources for the full
+ specification of other DEF file statements
+
+ While linking a shared dll, 'ld' is able to create a DEF file
+ with the '--output-def <file>' command line option.
+
+ _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:
+
+ __declspec(dllexport) int a_variable
+ __declspec(dllexport) void a_function(int with_args)
+
+ 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 '--export-all-symbols' option is also used.
+
+ Note that object files that wish to access these symbols must
+ _not_ decorate them with dllexport. Instead, they should use
+ dllimport, instead:
+
+ __declspec(dllimport) int a_variable
+ __declspec(dllimport) void a_function(int with_args)
+
+ 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 '--enable-auto-import' and
+ 'automatic data imports' for more information.
+
+_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
+ achieve a behavior that conforms to that on POSIX/Un*x platforms.
+ This feature is enabled with the '--enable-auto-import'
+ command-line option, although it is enabled by default on
+ cygwin/mingw. The '--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 '--enable-auto-import' for details."
+
+ The '--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 _runtime pseudo-relocs_
+ feature, described below.
+
+ For complex variables imported from DLLs (such as structs or
+ classes), object files typically contain a base address for the
+ variable and an offset (_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 '--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.
+
+ '--enable-runtime-pseudo-relocs' is not the default; it must be
+ explicitly enabled as needed.
+
+_direct linking to a dll_
+ The cygwin/mingw ports of '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, especially when linking
+ large libraries or applications. When '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 '-L' and '-l', because '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 '-lxxx' it will
+ attempt to find, in the first directory of its search path,
+
+ libxxx.dll.a
+ xxx.dll.a
+ libxxx.a
+ xxx.lib
+ cygxxx.dll (*)
+ libxxx.dll
+ xxx.dll
+
+ before moving on to the next directory in the search path.
+
+ (*) Actually, this is not 'cygxxx.dll' but in fact is
+ '<prefix>xxx.dll', where '<prefix>' is set by the 'ld' option
+ '--dll-search-prefix=<prefix>'. In the case of cygwin, the
+ standard gcc spec file includes '--dll-search-prefix=cyg', so in
+ effect we actually search for 'cygxxx.dll'.
+
+ Other win32-based unix environments, such as mingw or pw32, may use
+ other '<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 'bin' directory for
+ applications and dll's and a 'lib' directory for the import
+ libraries (using cygwin nomenclature):
+
+ bin/
+ cygxxx.dll
+ lib/
+ libxxx.dll.a (in case of dll's)
+ libxxx.a (in case of static archive)
+
+ Linking directly to a dll without using the import library can be
+ done two ways:
+
+ 1. Use the dll directly by adding the 'bin' path to the link line
+ gcc -Wl,-verbose -o a.exe -L../bin/ -lxxx
+
+ However, as the dll's often have version numbers appended to their
+ names ('cygncurses-5.dll') this will often fail, unless one
+ specifies '-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 '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.
+
+ ln -s bin/cygxxx.dll lib/[cyg|lib|]xxx.dll[.a]
+
+ Then you can link without any make environment changes.
+
+ gcc -Wl,-verbose -o a.exe -L../lib/ -lxxx
+
+ This technique also avoids the version number problems, because the
+ following is perfectly legal
+
+ bin/
+ cygxxx-5.dll
+ lib/
+ libxxx.dll.a -> ../bin/cygxxx-5.dll
+
+ Linking directly to a dll without using an import lib will work
+ even when auto-import features are exercised, and even when
+ '--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
+ three reasons:
+
+ 1. Until recently, the link-directly-to-dll functionality did
+ _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.
+
+ 3. Symbol aliases can only be resolved using an import lib. This
+ is critical when linking against OS-supplied dll's (eg, the win32
+ API) in which symbols are usually exported as undecorated aliases
+ of their stdcall-decorated assembly names.
+
+ 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 many 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.
+
+_symbol aliasing_
+ _adding additional names_
+ Sometimes, it is useful to export symbols with additional
+ names. A symbol 'foo' will be exported as 'foo', but it can
+ also be exported as '_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:
+
+ LIBRARY "xyz.dll" BASE=0x61000000
+
+ EXPORTS
+ foo
+ _foo = foo
+
+ The line '_foo = foo' maps the symbol 'foo' to '_foo'.
+
+ Another method for creating a symbol alias is to create it in
+ the source code using the "weak" attribute:
+
+ void foo () { /* Do something. */; }
+ void _foo () __attribute__ ((weak, alias ("foo")));
+
+ See the gcc manual for more information about attributes and
+ weak symbols.
+
+ _renaming symbols_
+ Sometimes it is useful to rename exports. For instance, the
+ cygwin kernel does this regularly. A symbol '_foo' can be
+ exported as 'foo' but not as '_foo' by using special
+ directives in the DEF file. (This will also affect the import
+ library, if it is created). In the following example:
+
+ LIBRARY "xyz.dll" BASE=0x61000000
+
+ EXPORTS
+ _foo = foo
+
+ The line '_foo = foo' maps the exported symbol 'foo' to
+ '_foo'.
+
+ Note: using a DEF file disables the default auto-export behavior,
+ unless the '--export-all-symbols' command line option is used. If,
+ however, you are trying to rename symbols, then you should list
+ _all_ desired exports in the DEF file, including the symbols that
+ are not being renamed, and do _not_ use the '--export-all-symbols'
+ option. If you list only the renamed symbols in the DEF file, and
+ use '--export-all-symbols' to handle the other symbols, then the
+ both the new names _and_ the original names for the renamed symbols
+ will be exported. In effect, you'd be aliasing those symbols, not
+ renaming them, which is probably not what you wanted.
+
+_weak externals_
+ The Windows object format, PE, specifies a form of weak symbols
+ called weak externals. When a weak symbol is linked and the symbol
+ is not defined, the weak symbol becomes an alias for some other
+ symbol. There are three variants of weak externals:
+ * Definition is searched for in objects and libraries,
+ historically called lazy externals.
+ * Definition is searched for only in other objects, not in
+ libraries. This form is not presently implemented.
+ * No search; the symbol is an alias. This form is not presently
+ implemented.
+ As a GNU extension, weak symbols that do not specify an alternate
+ symbol are supported. If the symbol is undefined when linking, the
+ symbol uses a default value.
+
+4.13 'ld' and Xtensa Processors
+===============================
+
+The default 'ld' behavior for Xtensa processors is to interpret
+'SECTIONS' commands so that lists of explicitly named sections in a
+specification with a wildcard file will be interleaved when necessary to
+keep literal pools within the range of PC-relative load offsets. For
+example, with the command:
+
+ SECTIONS
+ {
+ .text : {
+ *(.literal .text)
+ }
+ }
+
+'ld' may interleave some of the '.literal' and '.text' sections from
+different object files to ensure that the literal pools are within the
+range of PC-relative load offsets. A valid interleaving might place the
+'.literal' sections from an initial group of files followed by the
+'.text' sections of that group of files. Then, the '.literal' sections
+from the rest of the files and the '.text' sections from the rest of the
+files would follow.
+
+ Relaxation is enabled by default for the Xtensa version of 'ld' and
+provides two important link-time optimizations. The first optimization
+is to combine identical literal values to reduce code size. A redundant
+literal will be removed and all the 'L32R' instructions that use it will
+be changed to reference an identical literal, as long as the location of
+the replacement literal is within the offset range of all the 'L32R'
+instructions. The second optimization is to remove unnecessary overhead
+from assembler-generated "longcall" sequences of 'L32R'/'CALLXN' when
+the target functions are within range of direct 'CALLN' instructions.
+
+ For each of these cases where an indirect call sequence can be
+optimized to a direct call, the linker will change the 'CALLXN'
+instruction to a 'CALLN' instruction, remove the 'L32R' instruction, and
+remove the literal referenced by the 'L32R' instruction if it is not
+used for anything else. Removing the 'L32R' instruction always reduces
+code size but can potentially hurt performance by changing the alignment
+of subsequent branch targets. By default, the linker will always
+preserve alignments, either by switching some instructions between
+24-bit encodings and the equivalent density instructions or by inserting
+a no-op in place of the 'L32R' instruction that was removed. If code
+size is more important than performance, the '--size-opt' option can be
+used to prevent the linker from widening density instructions or
+inserting no-ops, except in a few cases where no-ops are required for
+correctness.
+
+ The following Xtensa-specific command-line options can be used to
+control the linker:
+
+'--no-relax'
+ Since the Xtensa version of 'ld' enables the '--relax' option by
+ default, the '--no-relax' option is provided to disable relaxation.
+
+'--size-opt'
+ When optimizing indirect calls to direct calls, optimize for code
+ size more than performance. With this option, the linker will not
+ insert no-ops or widen density instructions to preserve branch
+ target alignment. There may still be some cases where no-ops are
+ required to preserve the correctness of the code.
+
+5 BFD
+*****
+
+The linker accesses object and archive files using the BFD libraries.
+These libraries allow the linker to use the same routines to operate on
+object files whatever the object file format. A different object file
+format can be supported simply by creating a new BFD back end and adding
+it to the library. To conserve runtime memory, however, the linker and
+associated tools are usually configured to support only a subset of the
+object file formats available. You can use 'objdump -i' (*note objdump:
+(binutils.info)objdump.) to list all the formats available for your
+configuration.
+
+ As with most implementations, BFD is a compromise between several
+conflicting requirements. The major factor influencing BFD design was
+efficiency: any time used converting between formats is time which would
+not have been spent had BFD not been involved. This is partly offset by
+abstraction payback; since BFD simplifies applications and back ends,
+more time and care may be spent optimizing algorithms for a greater
+speed.
+
+ One minor artifact of the BFD solution which you should bear in mind
+is the potential for information loss. There are two places where
+useful information can be lost using the BFD mechanism: during
+conversion and during output. *Note BFD information loss::.
+
+5.1 How It Works: An Outline of BFD
+===================================
+
+When an object file is opened, BFD subroutines automatically determine
+the format of the input object file. They then build a descriptor in
+memory with pointers to routines that will be used to access elements of
+the object file's data structures.
+
+ As different information from the object files is required, BFD reads
+from different sections of the file and processes them. For example, a
+very common operation for the linker is processing symbol tables. Each
+BFD back end provides a routine for converting between the object file's
+representation of symbols and an internal canonical format. When the
+linker asks for the symbol table of an object file, it calls through a
+memory pointer to the routine from the relevant BFD back end which reads
+and converts the table into a canonical form. The linker then operates
+upon the canonical form. When the link is finished and the linker
+writes the output file's symbol table, another BFD back end routine is
+called to take the newly created symbol table and convert it into the
+chosen output format.
+
+5.1.1 Information Loss
+----------------------
+
+_Information can be lost during output._ The output formats supported
+by BFD do not provide identical facilities, and information which can be
+described in one form has nowhere to go in another format. One example
+of this is alignment information in 'b.out'. There is nowhere in an
+'a.out' format file to store alignment information on the contained
+data, so when a file is linked from 'b.out' and an 'a.out' image is
+produced, alignment information will not propagate to the output file.
+(The linker will still use the alignment information internally, so the
+link is performed correctly).
+
+ Another example is COFF section names. COFF files may contain an
+unlimited number of sections, each one with a textual section name. If
+the target of the link is a format which does not have many sections
+(e.g., 'a.out') or has sections without names (e.g., the Oasys format),
+the link cannot be done simply. You can circumvent this problem by
+describing the desired input-to-output section mapping with the linker
+command language.
+
+ _Information can be lost during canonicalization._ The BFD internal
+canonical form of the external formats is not exhaustive; there are
+structures in input formats for which there is no direct representation
+internally. This means that the BFD back ends cannot maintain all
+possible data richness through the transformation between external to
+internal and back to external formats.
+
+ This limitation is only a problem when an application reads one
+format and writes another. Each BFD back end is responsible for
+maintaining as much data as possible, and the internal BFD canonical
+form has structures which are opaque to the BFD core, and exported only
+to the back ends. When a file is read in one format, the canonical form
+is generated for BFD and the application. At the same time, the back
+end saves away any information which may otherwise be lost. If the data
+is then written back in the same format, the back end routine will be
+able to use the canonical form provided by the BFD core as well as the
+information it prepared earlier. Since there is a great deal of
+commonality between back ends, there is no information lost when linking
+or copying big endian COFF to little endian COFF, or 'a.out' to 'b.out'.
+When a mixture of formats is linked, the information is only lost from
+the files whose format differs from the destination.
+
+5.1.2 The BFD canonical object-file format
+------------------------------------------
+
+The greatest potential for loss of information occurs when there is the
+least overlap between the information provided by the source format,
+that stored by the canonical format, and that needed by the destination
+format. A brief description of the canonical form may help you
+understand which kinds of data you can count on preserving across
+conversions.
+
+_files_
+ Information stored on a per-file basis includes target machine
+ architecture, particular implementation format type, a demand
+ pageable bit, and a write protected bit. Information like Unix
+ magic numbers is not stored here--only the magic numbers' meaning,
+ so a 'ZMAGIC' file would have both the demand pageable bit and the
+ write protected text bit set. The byte order of the target is
+ stored on a per-file basis, so that big- and little-endian object
+ files may be used with one another.
+
+_sections_
+ Each section in the input file contains the name of the section,
+ the section's original address in the object file, size and
+ alignment information, various flags, and pointers into other BFD
+ data structures.
+
+_symbols_
+ Each symbol contains a pointer to the information for the object
+ file which originally defined it, its name, its value, and various
+ flag bits. When a BFD back end reads in a symbol table, it
+ relocates all symbols to make them relative to the base of the
+ section where they were defined. Doing this ensures that each
+ symbol points to its containing section. Each symbol also has a
+ varying amount of hidden private data for the BFD back end. Since
+ the symbol points to the original file, the private data format for
+ that symbol is accessible. 'ld' can operate on a collection of
+ symbols of wildly different formats without problems.
+
+ Normal global and simple local symbols are maintained on output, so
+ an output file (no matter its format) will retain symbols pointing
+ to functions and to global, static, and common variables. Some
+ symbol information is not worth retaining; in 'a.out', type
+ information is stored in the symbol table as long symbol names.
+ This information would be useless to most COFF debuggers; the
+ linker has command line switches to allow users to throw it away.
+
+ There is one word of type information within the symbol, so if the
+ format supports symbol type information within symbols (for
+ example, COFF, IEEE, Oasys) and the type is simple enough to fit
+ within one word (nearly everything but aggregates), the information
+ will be preserved.
+
+_relocation level_
+ Each canonical BFD relocation record contains a pointer to the
+ symbol to relocate to, the offset of the data to relocate, the
+ section the data is in, and a pointer to a relocation type
+ descriptor. Relocation is performed by passing messages through
+ the relocation type descriptor and the symbol pointer. Therefore,
+ relocations can be performed on output data using a relocation
+ method that is only available in one of the input formats. For
+ instance, Oasys provides a byte relocation format. A relocation
+ record requesting this relocation type would point indirectly to a
+ routine to perform this, so the relocation may be performed on a
+ byte being written to a 68k COFF file, even though 68k COFF has no
+ such relocation type.
+
+_line numbers_
+ Object formats can contain, for debugging purposes, some form of
+ mapping between symbols, source line numbers, and addresses in the
+ output file. These addresses have to be relocated along with the
+ symbol information. Each symbol with an associated list of line
+ number records points to the first record of the list. The head of
+ a line number list consists of a pointer to the symbol, which
+ allows finding out the address of the function whose line number is
+ being described. The rest of the list is made up of pairs: offsets
+ into the section and line numbers. Any format which can simply
+ derive this information can pass it successfully between formats
+ (COFF, IEEE and Oasys).
+
+6 Reporting Bugs
+****************
+
+Your bug reports play an essential role in making '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 'ld' work
+better. Bug reports are your contribution to the maintenance of 'ld'.
+
+ In order for a bug report to serve its purpose, you must include the
+information that enables us to fix the bug.
+
+6.1 Have You Found a Bug?
+=========================
+
+If you are not sure whether you have found a bug, here are some
+guidelines:
+
+ * If the linker gets a fatal signal, for any input whatever, that is
+ a 'ld' bug. Reliable linkers never crash.
+
+ * If 'ld' produces an error message for valid input, that is a bug.
+
+ * If '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.
+
+ * If you are an experienced user of linkers, your suggestions for
+ improvement of 'ld' are welcome in any case.
+
+6.2 How to Report Bugs
+======================
+
+A number of companies and individuals offer support for GNU products.
+If you obtained '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 'etc/SERVICE' in the GNU Emacs distribution.
+
+ The fundamental principle of reporting bugs usefully is this: *report
+all the facts*. If you are not sure whether to state a fact or leave it
+out, state it!
+
+ 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.
+
+ Sometimes people give a few sketchy facts and ask, "Does this ring a
+bell?" This cannot help us fix a bug, so it is basically useless. We
+respond by asking for enough details to enable us to investigate. You
+might as well expedite matters by sending them to begin with.
+
+ To enable us to fix the bug, you should include all these things:
+
+ * The version of 'ld'. 'ld' announces it if you start it with the
+ '--version' argument.
+
+ Without this, we will not know whether there is any point in
+ looking for the bug in the current version of 'ld'.
+
+ * Any patches you may have applied to the 'ld' source, including any
+ patches made to the 'BFD' library.
+
+ * The type of machine you are using, and the operating system name
+ and version number.
+
+ * What compiler (and its version) was used to compile 'ld'--e.g.
+ "'gcc-2.7'".
+
+ * The command arguments you gave the linker to link your example and
+ observe the bug. To guarantee you will not omit something
+ important, list them all. A copy of the Makefile (or the output
+ from make) is sufficient.
+
+ If we were to try to guess the arguments, we would probably guess
+ wrong and then we might not encounter the bug.
+
+ * 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 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 'gas' or compiled using
+ 'gcc', then it may be OK to send the source files rather than the
+ object files. In this case, be sure to say exactly what version of
+ 'gas' or 'gcc' was used to produce the object files. Also say how
+ 'gas' or 'gcc' were configured.
+
+ * 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 '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 'ld' is out of sync, 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 you had not told us to expect a
+ crash, then we would not be able to draw any conclusion from our
+ observations.
+
+ * If you wish to suggest changes to the 'ld' source, send us context
+ diffs, as generated by 'diff' with the '-u', '-c', or '-p' option.
+ Always send diffs from the old file to the new file. If you even
+ discuss something in the 'ld' source, refer to it by context, not
+ by line number.
+
+ The line numbers in our development sources will not match those in
+ your sources. Your line numbers would convey no useful information
+ to us.
+
+ Here are some things that are not necessary:
+
+ * A description of the envelope of the bug.
+
+ Often people who encounter a bug spend a lot of time investigating
+ which changes to the input file will make the bug go away and which
+ changes will not affect it.
+
+ This is often time consuming and not very useful, because the way
+ we will find the bug is by running a single example under the
+ debugger with breakpoints, not by pure deduction from a series of
+ examples. We recommend that you save your time for something else.
+
+ Of course, if you can find a simpler example to report _instead_ of
+ the original one, that is a convenience for us. Errors in the
+ output will be easier to spot, running under the debugger will take
+ less time, and so on.
+
+ However, simplification is not vital; if you do not want to do
+ this, report the bug anyway and send us the entire test case you
+ used.
+
+ * A patch for the bug.
+
+ A patch for the bug does help us if it is a good one. But do not
+ omit the necessary information, such as the test case, on the
+ assumption that 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 '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 fixed.
+
+ And if we cannot understand what bug you are trying to fix, or why
+ your patch should be an improvement, we will not install it. A
+ test case will help us to understand.
+
+ * A guess about what the bug is or what it depends on.
+
+ Such guesses are usually wrong. Even we cannot guess right about
+ such things without first using the debugger to find the facts.
+
+Appendix A MRI Compatible Script Files
+**************************************
+
+To aid users making the transition to GNU 'ld' from the MRI linker, 'ld'
+can use MRI compatible linker scripts as an alternative to the more
+general-purpose linker scripting language described in *note Scripts::.
+MRI compatible linker scripts have a much simpler command set than the
+scripting language otherwise used with 'ld'. GNU '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 'a.out' object
+file format, since it only has three sections and MRI scripts lack some
+features to make use of them.
+
+ You can specify a file containing an MRI-compatible script using the
+'-c' command-line option.
+
+ 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, 'ld' issues a
+warning message, but continues processing the script.
+
+ Lines beginning with '*' are comments.
+
+ You can write these commands using all upper-case letters, or all
+lower case; for example, 'chip' is the same as 'CHIP'. The following
+list shows only the upper-case form of each command.
+
+'ABSOLUTE SECNAME'
+'ABSOLUTE SECNAME, SECNAME, ... SECNAME'
+ Normally, 'ld' includes in the output file all sections from all
+ the input files. However, in an MRI-compatible script, you can use
+ the 'ABSOLUTE' command to restrict the sections that will be
+ present in your output program. If the 'ABSOLUTE' command is used
+ at all in a script, then only the sections named explicitly in
+ 'ABSOLUTE' commands will appear in the linker output. You can
+ still use other input sections (whatever you select on the command
+ line, or using 'LOAD') to resolve addresses in the output file.
+
+'ALIAS OUT-SECNAME, IN-SECNAME'
+ Use this command to place the data from input section IN-SECNAME in
+ a section called OUT-SECNAME in the linker output file.
+
+ IN-SECNAME may be an integer.
+
+'ALIGN SECNAME = EXPRESSION'
+ Align the section called SECNAME to EXPRESSION. The EXPRESSION
+ should be a power of two.
+
+'BASE EXPRESSION'
+ Use the value of EXPRESSION as the lowest address (other than
+ absolute addresses) in the output file.
+
+'CHIP EXPRESSION'
+'CHIP EXPRESSION, EXPRESSION'
+ This command does nothing; it is accepted only for compatibility.
+
+'END'
+ This command does nothing whatever; it's only accepted for
+ compatibility.
+
+'FORMAT OUTPUT-FORMAT'
+ Similar to the 'OUTPUT_FORMAT' command in the more general linker
+ language, but restricted to one of these output formats:
+
+ 1. S-records, if OUTPUT-FORMAT is 'S'
+
+ 2. IEEE, if OUTPUT-FORMAT is 'IEEE'
+
+ 3. COFF (the 'coff-m68k' variant in BFD), if OUTPUT-FORMAT is
+ 'COFF'
+
+'LIST ANYTHING...'
+ Print (to the standard output file) a link map, as produced by the
+ 'ld' command-line option '-M'.
+
+ The keyword 'LIST' may be followed by anything on the same line,
+ with no change in its effect.
+
+'LOAD FILENAME'
+'LOAD FILENAME, FILENAME, ... FILENAME'
+ Include one or more object file FILENAME in the link; this has the
+ same effect as specifying FILENAME directly on the 'ld' command
+ line.
+
+'NAME OUTPUT-NAME'
+ OUTPUT-NAME is the name for the program produced by 'ld'; the
+ MRI-compatible command 'NAME' is equivalent to the command-line
+ option '-o' or the general script language command 'OUTPUT'.
+
+'ORDER SECNAME, SECNAME, ... SECNAME'
+'ORDER SECNAME SECNAME SECNAME'
+ Normally, '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
+ 'ORDER' command. The sections you list with 'ORDER' will appear
+ first in your output file, in the order specified.
+
+'PUBLIC NAME=EXPRESSION'
+'PUBLIC NAME,EXPRESSION'
+'PUBLIC NAME EXPRESSION'
+ Supply a value (EXPRESSION) for external symbol NAME used in the
+ linker input files.
+
+'SECT SECNAME, EXPRESSION'
+'SECT SECNAME=EXPRESSION'
+'SECT SECNAME EXPRESSION'
+ You can use any of these three forms of the 'SECT' command to
+ specify the start address (EXPRESSION) for section SECNAME. If you
+ have more than one 'SECT' statement for the same SECNAME, only the
+ _first_ sets the start address.
+
+Appendix B GNU Free Documentation License
+*****************************************
+
+ Version 1.1, March 2000
+
+ Copyright (C) 2000, 2003 Free Software Foundation, Inc.
+ 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 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
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+ 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:
+
+ 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."
+
+ 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.
+
+LD Index
+********
+
+* Menu:
+
+* ": Symbols. (line 3620)
+* -(: Options. (line 756)
+* --accept-unknown-input-arch: Options. (line 774)
+* --add-needed: Options. (line 796)
+* --add-stdcall-alias: Options. (line 1532)
+* --allow-multiple-definition: Options. (line 1004)
+* --allow-shlib-undefined: Options. (line 1010)
+* --architecture=ARCH: Options. (line 227)
+* --as-needed: Options. (line 784)
+* --auxiliary: Options. (line 328)
+* --bank-window: Options. (line 1867)
+* --base-file: Options. (line 1537)
+* --be8: ARM. (line 4205)
+* --bss-plt: PowerPC ELF32. (line 4376)
+* --check-sections: Options. (line 877)
+* --cref: Options. (line 887)
+* --default-imported-symver: Options. (line 1038)
+* --default-script=SCRIPT: Options. (line 601)
+* --default-symver: Options. (line 1034)
+* --defsym SYMBOL=EXP: Options. (line 915)
+* --demangle[=STYLE]: Options. (line 928)
+* --disable-auto-image-base: Options. (line 1682)
+* --disable-auto-import: Options. (line 1810)
+* --disable-new-dtags: Options. (line 1479)
+* --disable-runtime-pseudo-reloc: Options. (line 1823)
+* --disable-stdcall-fixup: Options. (line 1547)
+* --discard-all: Options. (line 647)
+* --discard-locals: Options. (line 651)
+* --dll: Options. (line 1542)
+* --dll-search-prefix: Options. (line 1688)
+* --dotsyms: PowerPC64 ELF64. (line 4446)
+* --dynamic-linker FILE: Options. (line 941)
+* --dynamic-list-cpp-new: Options. (line 869)
+* --dynamic-list-cpp-typeinfo: Options. (line 873)
+* --dynamic-list-data: Options. (line 866)
+* --dynamic-list=DYNAMIC-LIST-FILE: Options. (line 853)
+* --eh-frame-hdr: Options. (line 1475)
+* --emit-relocs: Options. (line 537)
+* --emit-stack-syms: SPU ELF. (line 4541)
+* --emit-stub-syms: PowerPC ELF32. (line 4407)
+* --emit-stub-syms <1>: PowerPC64 ELF64. (line 4442)
+* --emit-stub-syms <2>: SPU ELF. (line 4510)
+* --enable-auto-image-base: Options. (line 1674)
+* --enable-auto-import: Options. (line 1697)
+* --enable-extra-pe-debug: Options. (line 1828)
+* --enable-new-dtags: Options. (line 1479)
+* --enable-runtime-pseudo-reloc: Options. (line 1815)
+* --enable-stdcall-fixup: Options. (line 1547)
+* --entry=ENTRY: Options. (line 281)
+* --error-unresolved-symbols: Options. (line 1428)
+* --exclude-libs: Options. (line 291)
+* --exclude-symbols: Options. (line 1588)
+* --export-all-symbols: Options. (line 1564)
+* --export-dynamic: Options. (line 302)
+* --extra-overlay-stubs: SPU ELF. (line 4514)
+* --fatal-warnings: Options. (line 947)
+* --file-alignment: Options. (line 1594)
+* --filter: Options. (line 349)
+* --fix-v4bx: ARM. (line 4224)
+* --force-dynamic: Options. (line 546)
+* --force-exe-suffix: Options. (line 950)
+* --format=FORMAT: Options. (line 238)
+* --format=VERSION: TI COFF. (line 4554)
+* --gc-sections: Options. (line 960)
+* --gpsize: Options. (line 381)
+* --hash-size=NUMBER: Options. (line 1488)
+* --hash-style=STYLE: Options. (line 1496)
+* --heap: Options. (line 1600)
+* --help: Options. (line 977)
+* --image-base: Options. (line 1607)
+* --just-symbols=FILE: Options. (line 568)
+* --kill-at: Options. (line 1616)
+* --large-address-aware: Options. (line 1621)
+* --library-path=DIR: Options. (line 440)
+* --library=NAMESPEC: Options. (line 407)
+* --local-store=lo:hi: SPU ELF. (line 4519)
+* --major-image-version: Options. (line 1630)
+* --major-os-version: Options. (line 1635)
+* --major-subsystem-version: Options. (line 1639)
+* --minor-image-version: Options. (line 1644)
+* --minor-os-version: Options. (line 1649)
+* --minor-subsystem-version: Options. (line 1653)
+* --mri-script=MRI-CMDFILE: Options. (line 262)
+* --multi-subspace: HPPA ELF32. (line 4285)
+* --nmagic: Options. (line 506)
+* --no-accept-unknown-input-arch: Options. (line 774)
+* --no-add-needed: Options. (line 796)
+* --no-allow-shlib-undefined: Options. (line 1010)
+* --no-as-needed: Options. (line 784)
+* --no-check-sections: Options. (line 877)
+* --no-define-common: Options. (line 899)
+* --no-demangle: Options. (line 928)
+* --no-dotsyms: PowerPC64 ELF64. (line 4446)
+* --no-enum-size-warning: ARM. (line 4275)
+* --no-gc-sections: Options. (line 960)
+* --no-keep-memory: Options. (line 989)
+* --no-multi-toc: PowerPC64 ELF64. (line 4487)
+* --no-omagic: Options. (line 520)
+* --no-opd-optimize: PowerPC64 ELF64. (line 4461)
+* --no-overlays: SPU ELF. (line 4504)
+* --no-print-gc-sections: Options. (line 968)
+* --no-relax: Xtensa. (line 5005)
+* --no-tls-optimize: PowerPC ELF32. (line 4411)
+* --no-tls-optimize <1>: PowerPC64 ELF64. (line 4456)
+* --no-toc-optimize: PowerPC64 ELF64. (line 4473)
+* --no-trampoline: Options. (line 1861)
+* --no-undefined: Options. (line 996)
+* --no-undefined-version: Options. (line 1029)
+* --no-warn-mismatch: Options. (line 1042)
+* --no-warn-search-mismatch: Options. (line 1051)
+* --no-whole-archive: Options. (line 1055)
+* --noinhibit-exec: Options. (line 1059)
+* --non-overlapping-opd: PowerPC64 ELF64. (line 4467)
+* --oformat: Options. (line 1070)
+* --omagic: Options. (line 511)
+* --out-implib: Options. (line 1666)
+* --output-def: Options. (line 1658)
+* --output=OUTPUT: Options. (line 526)
+* --pic-executable: Options. (line 1083)
+* --pic-veneer: M68HC11/68HC12. (line 4180)
+* --plugin: SPU ELF. (line 4501)
+* --print-gc-sections: Options. (line 968)
+* --print-map: Options. (line 472)
+* --reduce-memory-overheads: Options. (line 1502)
+* --relax: Options. (line 1099)
+* '--relax' on i960: i960. (line 4138)
+* --relax on PowerPC: PowerPC ELF32. (line 4369)
+* '--relax' on Xtensa: Xtensa. (line 4977)
+* --relocatable: Options. (line 550)
+* --script=SCRIPT: Options. (line 592)
+* --sdata-got: PowerPC ELF32. (line 4393)
+* --section-alignment: Options. (line 1833)
+* --section-start SECTIONNAME=ORG: Options. (line 1265)
+* --secure-plt: PowerPC ELF32. (line 4386)
+* --sort-common: Options. (line 1212)
+* --sort-section alignment: Options. (line 1222)
+* --sort-section name: Options. (line 1218)
+* --split-by-file: Options. (line 1226)
+* --split-by-reloc: Options. (line 1231)
+* --stack: Options. (line 1839)
+* --stack-analysis: SPU ELF. (line 4524)
+* --stats: Options. (line 1244)
+* --strip-all: Options. (line 579)
+* --strip-debug: Options. (line 583)
+* --stub-group-size: PowerPC64 ELF64. (line 4419)
+* --stub-group-size=N: HPPA ELF32. (line 4291)
+* --subsystem: Options. (line 1846)
+* --support-old-code: ARM. (line 4188)
+* --sysroot: Options. (line 1248)
+* --target-help: Options. (line 981)
+* --target1-abs: ARM. (line 4209)
+* --target1-rel: ARM. (line 4209)
+* --target2=TYPE: ARM. (line 4214)
+* --thumb-entry=ENTRY: ARM. (line 4199)
+* --trace: Options. (line 588)
+* --trace-symbol=SYMBOL: Options. (line 657)
+* --traditional-format: Options. (line 1253)
+* --undefined=SYMBOL: Options. (line 614)
+* --unique[=SECTION]: Options. (line 632)
+* --unresolved-symbols: Options. (line 1280)
+* --use-blx: ARM. (line 4237)
+* --verbose: Options. (line 1309)
+* --version: Options. (line 641)
+* --version-script=VERSION-SCRIPTFILE: Options. (line 1315)
+* --vfp11-denorm-fix: ARM. (line 4246)
+* --warn-common: Options. (line 1322)
+* --warn-constructors: Options. (line 1390)
+* --warn-multiple-gp: Options. (line 1395)
+* --warn-once: Options. (line 1409)
+* --warn-section-align: Options. (line 1413)
+* --warn-shared-textrel: Options. (line 1420)
+* --warn-unresolved-symbols: Options. (line 1423)
+* --whole-archive: Options. (line 1432)
+* --wrap: Options. (line 1446)
+* -AARCH: Options. (line 226)
+* -aKEYWORD: Options. (line 219)
+* -assert KEYWORD: Options. (line 806)
+* -b FORMAT: Options. (line 238)
+* -Bdynamic: Options. (line 809)
+* -Bgroup: Options. (line 819)
+* -Bshareable: Options. (line 1204)
+* -Bstatic: Options. (line 826)
+* -Bsymbolic: Options. (line 840)
+* -Bsymbolic-functions: Options. (line 847)
+* -c MRI-CMDFILE: Options. (line 262)
+* -call_shared: Options. (line 809)
+* -d: Options. (line 272)
+* -dc: Options. (line 272)
+* -dn: Options. (line 826)
+* -dp: Options. (line 272)
+* -dT SCRIPT: Options. (line 601)
+* -dy: Options. (line 809)
+* -E: Options. (line 302)
+* -e ENTRY: Options. (line 281)
+* -EB: Options. (line 321)
+* -EL: Options. (line 324)
+* -f: Options. (line 328)
+* -F: Options. (line 349)
+* -fini: Options. (line 372)
+* -g: Options. (line 378)
+* -G: Options. (line 381)
+* -hNAME: Options. (line 389)
+* -i: Options. (line 398)
+* -IFILE: Options. (line 941)
+* -init: Options. (line 401)
+* -LDIR: Options. (line 440)
+* -lNAMESPEC: Options. (line 407)
+* -M: Options. (line 472)
+* -m EMULATION: Options. (line 462)
+* -Map: Options. (line 985)
+* -n: Options. (line 506)
+* -N: Options. (line 511)
+* -non_shared: Options. (line 826)
+* -nostdlib: Options. (line 1065)
+* -O LEVEL: Options. (line 532)
+* -o OUTPUT: Options. (line 526)
+* -pie: Options. (line 1083)
+* -q: Options. (line 537)
+* -qmagic: Options. (line 1093)
+* -Qy: Options. (line 1096)
+* -r: Options. (line 550)
+* -R FILE: Options. (line 568)
+* -rpath: Options. (line 1134)
+* -rpath-link: Options. (line 1156)
+* -s: Options. (line 579)
+* -S: Options. (line 583)
+* -shared: Options. (line 1204)
+* -soname=NAME: Options. (line 389)
+* -static: Options. (line 826)
+* -t: Options. (line 588)
+* -T SCRIPT: Options. (line 592)
+* -Tbss ORG: Options. (line 1274)
+* -Tdata ORG: Options. (line 1274)
+* -Ttext ORG: Options. (line 1274)
+* -u SYMBOL: Options. (line 614)
+* -Ur: Options. (line 622)
+* -v: Options. (line 641)
+* -V: Options. (line 641)
+* -x: Options. (line 647)
+* -X: Options. (line 651)
+* -Y PATH: Options. (line 666)
+* -y SYMBOL: Options. (line 657)
+* -z defs: Options. (line 996)
+* -z KEYWORD: Options. (line 670)
+* -z muldefs: Options. (line 1004)
+* .: Location Counter. (line 3650)
+* /DISCARD/: Output Section Discarding.
+ (line 2932)
+* :PHDR: Output Section Phdr.
+ (line 3065)
+* =FILLEXP: Output Section Fill.
+ (line 3079)
+* >REGION: Output Section Region.
+ (line 3055)
+* [COMMON]: Input Section Common.
+ (line 2744)
+* 'ABSOLUTE' (MRI): MRI. (line 5391)
+* absolute and relocatable symbols: Expression Section. (line 3828)
+* absolute expressions: Expression Section. (line 3828)
+* ABSOLUTE(EXP): Builtin Functions. (line 3864)
+* ADDR(SECTION): Builtin Functions. (line 3871)
+* address, section: Output Section Address.
+ (line 2522)
+* 'ALIAS' (MRI): MRI. (line 5402)
+* 'ALIGN' (MRI): MRI. (line 5408)
+* align expression: Builtin Functions. (line 3890)
+* align location counter: Builtin Functions. (line 3890)
+* ALIGN(ALIGN): Builtin Functions. (line 3890)
+* ALIGN(EXP,ALIGN): Builtin Functions. (line 3890)
+* ALIGN(SECTION_ALIGN): Forced Output Alignment.
+ (line 3043)
+* ALIGNOF(SECTION): Builtin Functions. (line 3915)
+* allocating memory: MEMORY. (line 3196)
+* architecture: Miscellaneous Commands.
+ (line 2254)
+* architectures: Options. (line 226)
+* archive files, from cmd line: Options. (line 407)
+* archive search path in linker script: File Commands. (line 2158)
+* arithmetic: Expressions. (line 3591)
+* arithmetic operators: Operators. (line 3773)
+* ARM interworking support: ARM. (line 4188)
+* ASSERT: Miscellaneous Commands.
+ (line 2217)
+* assertion in linker script: Miscellaneous Commands.
+ (line 2217)
+* assignment in scripts: Assignments. (line 2262)
+* AS_NEEDED(FILES): File Commands. (line 2138)
+* AT(LMA): Output Section LMA. (line 2983)
+* AT>LMA_REGION: Output Section LMA. (line 2983)
+* automatic data imports: WIN32. (line 4723)
+* back end: BFD. (line 5019)
+* 'BASE' (MRI): MRI. (line 5412)
+* BE8: ARM. (line 4205)
+* BFD canonical format: Canonical format. (line 5114)
+* BFD requirements: BFD. (line 5029)
+* big-endian objects: Options. (line 321)
+* binary input format: Options. (line 238)
+* BLOCK(EXP): Builtin Functions. (line 3928)
+* bug criteria: Bug Criteria. (line 5201)
+* bug reports: Bug Reporting. (line 5219)
+* bugs in 'ld': Reporting Bugs. (line 5188)
+* BYTE(EXPRESSION): Output Section Data.
+ (line 2788)
+* C++ constructors, arranging in link: Output Section Keywords.
+ (line 2857)
+* 'CHIP' (MRI): MRI. (line 5416)
+* COLLECT_NO_DEMANGLE: Environment. (line 1899)
+* combining symbols, warnings on: Options. (line 1322)
+* command files: Scripts. (line 1908)
+* command line: Options. (line 130)
+* common allocation: Options. (line 272)
+* common allocation <1>: Options. (line 899)
+* common allocation in linker script: Miscellaneous Commands.
+ (line 2228)
+* common allocation in linker script <1>: Miscellaneous Commands.
+ (line 2233)
+* common symbol placement: Input Section Common.
+ (line 2721)
+* compatibility, MRI: Options. (line 262)
+* constants in linker scripts: Constants. (line 3604)
+* constructors: Options. (line 622)
+* CONSTRUCTORS: Output Section Keywords.
+ (line 2857)
+* constructors, arranging in link: Output Section Keywords.
+ (line 2857)
+* crash of linker: Bug Criteria. (line 5204)
+* CREATE_OBJECT_SYMBOLS: Output Section Keywords.
+ (line 2847)
+* creating a DEF file: WIN32. (line 4691)
+* cross reference table: Options. (line 887)
+* cross references: Miscellaneous Commands.
+ (line 2238)
+* current output location: Location Counter. (line 3650)
+* data: Output Section Data.
+ (line 2788)
+* DATA_SEGMENT_ALIGN(MAXPAGESIZE, COMMONPAGESIZE): Builtin Functions.
+ (line 3933)
+* DATA_SEGMENT_END(EXP): Builtin Functions. (line 3954)
+* DATA_SEGMENT_RELRO_END(OFFSET, EXP): Builtin Functions. (line 3960)
+* dbx: Options. (line 1258)
+* DEF files, creating: Options. (line 1658)
+* default emulation: Environment. (line 1891)
+* default input format: Environment. (line 1879)
+* DEFINED(SYMBOL): Builtin Functions. (line 3971)
+* deleting local symbols: Options. (line 647)
+* demangling, default: Environment. (line 1899)
+* demangling, from command line: Options. (line 928)
+* direct linking to a dll: WIN32. (line 4771)
+* discarding sections: Output Section Discarding.
+ (line 2917)
+* discontinuous memory: MEMORY. (line 3196)
+* DLLs, creating: Options. (line 1564)
+* DLLs, creating <1>: Options. (line 1658)
+* DLLs, creating <2>: Options. (line 1666)
+* DLLs, linking to: Options. (line 1688)
+* dot: Location Counter. (line 3650)
+* dot inside sections: Location Counter. (line 3680)
+* dot outside sections: Location Counter. (line 3710)
+* dynamic linker, from command line: Options. (line 941)
+* dynamic symbol table: Options. (line 302)
+* ELF program headers: PHDRS. (line 3293)
+* emulation: Options. (line 462)
+* emulation, default: Environment. (line 1891)
+* 'END' (MRI): MRI. (line 5420)
+* endianness: Options. (line 321)
+* entry point: Entry Point. (line 2076)
+* entry point, from command line: Options. (line 281)
+* entry point, thumb: ARM. (line 4199)
+* ENTRY(SYMBOL): Entry Point. (line 2076)
+* error on valid input: Bug Criteria. (line 5207)
+* example of linker script: Simple Example. (line 2005)
+* exporting DLL symbols: WIN32. (line 4576)
+* expression evaluation order: Evaluation. (line 3794)
+* expression sections: Expression Section. (line 3828)
+* expression, absolute: Builtin Functions. (line 3864)
+* expressions: Expressions. (line 3591)
+* EXTERN: Miscellaneous Commands.
+ (line 2221)
+* fatal signal: Bug Criteria. (line 5204)
+* file name wildcard patterns: Input Section Wildcards.
+ (line 2616)
+* FILEHDR: PHDRS. (line 3348)
+* filename symbols: Output Section Keywords.
+ (line 2847)
+* fill pattern, entire section: Output Section Fill.
+ (line 3079)
+* FILL(EXPRESSION): Output Section Data.
+ (line 2821)
+* finalization function: Options. (line 372)
+* first input file: File Commands. (line 2166)
+* first instruction: Entry Point. (line 2076)
+* FIX_V4BX: ARM. (line 4224)
+* FORCE_COMMON_ALLOCATION: Miscellaneous Commands.
+ (line 2228)
+* forcing input section alignment: Forced Input Alignment.
+ (line 3048)
+* forcing output section alignment: Forced Output Alignment.
+ (line 3043)
+* forcing the creation of dynamic sections: Options. (line 546)
+* 'FORMAT' (MRI): MRI. (line 5424)
+* functions in expressions: Builtin Functions. (line 3860)
+* garbage collection: Options. (line 960)
+* garbage collection <1>: Options. (line 968)
+* garbage collection <2>: Input Section Keep. (line 2750)
+* generating optimized output: Options. (line 532)
+* GNU linker: Overview. (line 100)
+* GNUTARGET: Environment. (line 1879)
+* GROUP(FILES): File Commands. (line 2131)
+* grouping input files: File Commands. (line 2131)
+* groups of archives: Options. (line 756)
+* H8/300 support: H8/300. (line 4078)
+* header size: Builtin Functions. (line 4035)
+* heap size: Options. (line 1600)
+* help: Options. (line 977)
+* holes: Location Counter. (line 3656)
+* holes, filling: Output Section Data.
+ (line 2821)
+* HPPA multiple sub-space stubs: HPPA ELF32. (line 4285)
+* HPPA stub grouping: HPPA ELF32. (line 4291)
+* i960 support: i960. (line 4112)
+* image base: Options. (line 1607)
+* implicit linker scripts: Implicit Linker Scripts.
+ (line 4054)
+* import libraries: WIN32. (line 4567)
+* INCLUDE FILENAME: File Commands. (line 2096)
+* including a linker script: File Commands. (line 2096)
+* including an entire archive: Options. (line 1432)
+* incremental link: Options. (line 398)
+* INHIBIT_COMMON_ALLOCATION: Miscellaneous Commands.
+ (line 2233)
+* initialization function: Options. (line 401)
+* initialized data in ROM: Output Section LMA. (line 3003)
+* input file format in linker script: Format Commands. (line 2204)
+* input filename symbols: Output Section Keywords.
+ (line 2847)
+* input files in linker scripts: File Commands. (line 2103)
+* input files, displaying: Options. (line 588)
+* input format: Options. (line 238)
+* input format <1>: Options. (line 238)
+* input object files in linker scripts: File Commands. (line 2103)
+* input section alignment: Forced Input Alignment.
+ (line 3048)
+* input section basics: Input Section Basics.
+ (line 2568)
+* input section wildcards: Input Section Wildcards.
+ (line 2616)
+* input sections: Input Section. (line 2558)
+* INPUT(FILES): File Commands. (line 2103)
+* integer notation: Constants. (line 3604)
+* integer suffixes: Constants. (line 3610)
+* internal object-file format: Canonical format. (line 5114)
+* invalid input: Bug Criteria. (line 5209)
+* K and M integer suffixes: Constants. (line 3610)
+* KEEP: Input Section Keep. (line 2750)
+* l =: MEMORY. (line 3256)
+* lazy evaluation: Evaluation. (line 3794)
+* 'ld' bugs, reporting: Bug Reporting. (line 5219)
+* LDEMULATION: Environment. (line 1891)
+* len =: MEMORY. (line 3256)
+* LENGTH =: MEMORY. (line 3256)
+* LENGTH(MEMORY): Builtin Functions. (line 3988)
+* library search path in linker script: File Commands. (line 2158)
+* link map: Options. (line 472)
+* link-time runtime library search path: Options. (line 1156)
+* linker crash: Bug Criteria. (line 5204)
+* linker script concepts: Basic Script Concepts.
+ (line 1935)
+* linker script example: Simple Example. (line 2005)
+* linker script file commands: File Commands. (line 2093)
+* linker script format: Script Format. (line 1985)
+* linker script input object files: File Commands. (line 2103)
+* linker script simple commands: Simple Commands. (line 2071)
+* linker scripts: Scripts. (line 1908)
+* 'LIST' (MRI): MRI. (line 5435)
+* little-endian objects: Options. (line 324)
+* 'LOAD' (MRI): MRI. (line 5442)
+* load address: Output Section LMA. (line 2983)
+* LOADADDR(SECTION): Builtin Functions. (line 3991)
+* loading, preventing: Output Section Type.
+ (line 2969)
+* local symbols, deleting: Options. (line 651)
+* location counter: Location Counter. (line 3650)
+* LONG(EXPRESSION): Output Section Data.
+ (line 2788)
+* M and K integer suffixes: Constants. (line 3610)
+* M68HC11 and 68HC12 support: M68HC11/68HC12. (line 4148)
+* machine architecture: Miscellaneous Commands.
+ (line 2254)
+* machine dependencies: Machine Dependent. (line 4071)
+* mapping input sections to output sections: Input Section. (line 2558)
+* MAX: Builtin Functions. (line 3995)
+* MEMORY: MEMORY. (line 3196)
+* memory region attributes: MEMORY. (line 3222)
+* memory regions: MEMORY. (line 3196)
+* memory regions and sections: Output Section Region.
+ (line 3055)
+* memory usage: Options. (line 989)
+* MIN: Builtin Functions. (line 3998)
+* MRI compatibility: MRI. (line 5365)
+* MSP430 extra sections: MSP430. (line 4343)
+* 'NAME' (MRI): MRI. (line 5448)
+* name, section: Output Section Name.
+ (line 2506)
+* names: Symbols. (line 3620)
+* naming the output file: Options. (line 526)
+* NEXT(EXP): Builtin Functions. (line 4002)
+* NMAGIC: Options. (line 506)
+* NOCROSSREFS(SECTIONS): Miscellaneous Commands.
+ (line 2238)
+* NOLOAD: Output Section Type.
+ (line 2969)
+* not enough room for program headers: Builtin Functions. (line 4040)
+* NO_ENUM_SIZE_WARNING: ARM. (line 4275)
+* o =: MEMORY. (line 3251)
+* objdump -i: BFD. (line 5019)
+* object file management: BFD. (line 5019)
+* object files: Options. (line 153)
+* object formats available: BFD. (line 5019)
+* object size: Options. (line 381)
+* OMAGIC: Options. (line 511)
+* OMAGIC <1>: Options. (line 520)
+* opening object files: BFD outline. (line 5045)
+* operators for arithmetic: Operators. (line 3773)
+* options: Options. (line 130)
+* 'ORDER' (MRI): MRI. (line 5453)
+* org =: MEMORY. (line 3251)
+* ORIGIN =: MEMORY. (line 3251)
+* ORIGIN(MEMORY): Builtin Functions. (line 4008)
+* orphan: Orphan Sections. (line 3635)
+* output file after errors: Options. (line 1059)
+* output file format in linker script: Format Commands. (line 2179)
+* output file name in linker script: File Commands. (line 2148)
+* output section alignment: Forced Output Alignment.
+ (line 3043)
+* output section attributes: Output Section Attributes.
+ (line 2939)
+* output section data: Output Section Data.
+ (line 2788)
+* OUTPUT(FILENAME): File Commands. (line 2148)
+* OUTPUT_ARCH(BFDARCH): Miscellaneous Commands.
+ (line 2254)
+* OUTPUT_FORMAT(BFDNAME): Format Commands. (line 2179)
+* OVERLAY: Overlay Description.
+ (line 3101)
+* overlays: Overlay Description.
+ (line 3101)
+* partial link: Options. (line 550)
+* PHDRS: PHDRS. (line 3293)
+* PHDRS <1>: PHDRS. (line 3348)
+* PIC_VENEER: M68HC11/68HC12. (line 4180)
+* position independent executables: Options. (line 1085)
+* PowerPC ELF32 options: PowerPC ELF32. (line 4376)
+* PowerPC GOT: PowerPC ELF32. (line 4393)
+* PowerPC long branches: PowerPC ELF32. (line 4369)
+* PowerPC PLT: PowerPC ELF32. (line 4376)
+* PowerPC stub symbols: PowerPC ELF32. (line 4407)
+* PowerPC TLS optimization: PowerPC ELF32. (line 4411)
+* PowerPC64 dot symbols: PowerPC64 ELF64. (line 4446)
+* PowerPC64 ELF64 options: PowerPC64 ELF64. (line 4419)
+* PowerPC64 multi-TOC: PowerPC64 ELF64. (line 4487)
+* PowerPC64 OPD optimization: PowerPC64 ELF64. (line 4461)
+* PowerPC64 OPD spacing: PowerPC64 ELF64. (line 4467)
+* PowerPC64 stub grouping: PowerPC64 ELF64. (line 4419)
+* PowerPC64 stub symbols: PowerPC64 ELF64. (line 4442)
+* PowerPC64 TLS optimization: PowerPC64 ELF64. (line 4456)
+* PowerPC64 TOC optimization: PowerPC64 ELF64. (line 4473)
+* precedence in expressions: Operators. (line 3773)
+* prevent unnecessary loading: Output Section Type.
+ (line 2969)
+* program headers: PHDRS. (line 3293)
+* program headers and sections: Output Section Phdr.
+ (line 3065)
+* program headers, not enough room: Builtin Functions. (line 4040)
+* program segments: PHDRS. (line 3293)
+* PROVIDE: PROVIDE. (line 2321)
+* PROVIDE_HIDDEN: PROVIDE_HIDDEN. (line 2350)
+* 'PUBLIC' (MRI): MRI. (line 5461)
+* QUAD(EXPRESSION): Output Section Data.
+ (line 2788)
+* quoted symbol names: Symbols. (line 3620)
+* read-only text: Options. (line 506)
+* read/write from cmd line: Options. (line 511)
+* regions of memory: MEMORY. (line 3196)
+* relative expressions: Expression Section. (line 3828)
+* relaxing addressing modes: Options. (line 1099)
+* relaxing on H8/300: H8/300. (line 4081)
+* relaxing on i960: i960. (line 4138)
+* relaxing on M68HC11: M68HC11/68HC12. (line 4155)
+* relaxing on Xtensa: Xtensa. (line 4977)
+* relocatable and absolute symbols: Expression Section. (line 3828)
+* relocatable output: Options. (line 550)
+* removing sections: Output Section Discarding.
+ (line 2917)
+* reporting bugs in 'ld': Reporting Bugs. (line 5188)
+* requirements for BFD: BFD. (line 5029)
+* retain relocations in final executable: Options. (line 537)
+* retaining specified symbols: Options. (line 1120)
+* ROM initialized data: Output Section LMA. (line 3003)
+* round up expression: Builtin Functions. (line 3890)
+* round up location counter: Builtin Functions. (line 3890)
+* runtime library name: Options. (line 389)
+* runtime library search path: Options. (line 1134)
+* runtime pseudo-relocation: WIN32. (line 4749)
+* scaled integers: Constants. (line 3610)
+* scommon section: Input Section Common.
+ (line 2735)
+* script files: Options. (line 592)
+* script files <1>: Options. (line 601)
+* scripts: Scripts. (line 1908)
+* search directory, from cmd line: Options. (line 440)
+* search path in linker script: File Commands. (line 2158)
+* SEARCH_DIR(PATH): File Commands. (line 2158)
+* 'SECT' (MRI): MRI. (line 5467)
+* section address: Output Section Address.
+ (line 2522)
+* section address in expression: Builtin Functions. (line 3871)
+* section alignment: Builtin Functions. (line 3915)
+* section alignment, warnings on: Options. (line 1413)
+* section data: Output Section Data.
+ (line 2788)
+* section fill pattern: Output Section Fill.
+ (line 3079)
+* section load address: Output Section LMA. (line 2983)
+* section load address in expression: Builtin Functions. (line 3991)
+* section name: Output Section Name.
+ (line 2506)
+* section name wildcard patterns: Input Section Wildcards.
+ (line 2616)
+* section size: Builtin Functions. (line 4019)
+* section, assigning to memory region: Output Section Region.
+ (line 3055)
+* section, assigning to program header: Output Section Phdr.
+ (line 3065)
+* SECTIONS: SECTIONS. (line 2443)
+* sections, discarding: Output Section Discarding.
+ (line 2917)
+* segment origins, cmd line: Options. (line 1274)
+* segments, ELF: PHDRS. (line 3293)
+* SEGMENT_START(SEGMENT, DEFAULT): Builtin Functions. (line 4011)
+* shared libraries: Options. (line 1206)
+* SHORT(EXPRESSION): Output Section Data.
+ (line 2788)
+* SIZEOF(SECTION): Builtin Functions. (line 4019)
+* SIZEOF_HEADERS: Builtin Functions. (line 4035)
+* small common symbols: Input Section Common.
+ (line 2735)
+* SORT: Input Section Wildcards.
+ (line 2665)
+* SORT_BY_ALIGNMENT: Input Section Wildcards.
+ (line 2661)
+* SORT_BY_NAME: Input Section Wildcards.
+ (line 2653)
+* SPU: SPU ELF. (line 4524)
+* SPU <1>: SPU ELF. (line 4541)
+* SPU ELF options: SPU ELF. (line 4501)
+* SPU extra overlay stubs: SPU ELF. (line 4514)
+* SPU local store size: SPU ELF. (line 4519)
+* SPU overlay stub symbols: SPU ELF. (line 4510)
+* SPU overlays: SPU ELF. (line 4504)
+* SPU plugins: SPU ELF. (line 4501)
+* SQUAD(EXPRESSION): Output Section Data.
+ (line 2788)
+* stack size: Options. (line 1839)
+* standard Unix system: Options. (line 131)
+* start of execution: Entry Point. (line 2076)
+* STARTUP(FILENAME): File Commands. (line 2166)
+* strip all symbols: Options. (line 579)
+* strip debugger symbols: Options. (line 583)
+* stripping all but some symbols: Options. (line 1120)
+* SUBALIGN(SUBSECTION_ALIGN): Forced Input Alignment.
+ (line 3048)
+* suffixes for integers: Constants. (line 3610)
+* symbol defaults: Builtin Functions. (line 3971)
+* symbol definition, scripts: Assignments. (line 2262)
+* symbol names: Symbols. (line 3620)
+* symbol tracing: Options. (line 657)
+* symbol versions: VERSION. (line 3424)
+* symbol-only input: Options. (line 568)
+* symbols, from command line: Options. (line 915)
+* symbols, relocatable and absolute: Expression Section. (line 3828)
+* symbols, retaining selectively: Options. (line 1120)
+* synthesizing linker: Options. (line 1099)
+* synthesizing on H8/300: H8/300. (line 4086)
+* TARGET(BFDNAME): Format Commands. (line 2204)
+* TARGET1: ARM. (line 4209)
+* TARGET2: ARM. (line 4214)
+* thumb entry point: ARM. (line 4199)
+* TI COFF versions: TI COFF. (line 4554)
+* traditional format: Options. (line 1253)
+* trampoline generation on M68HC11: M68HC11/68HC12. (line 4173)
+* trampoline generation on M68HC12: M68HC11/68HC12. (line 4173)
+* unallocated address, next: Builtin Functions. (line 4002)
+* undefined symbol: Options. (line 614)
+* undefined symbol in linker script: Miscellaneous Commands.
+ (line 2221)
+* undefined symbols, warnings on: Options. (line 1409)
+* uninitialized data placement: Input Section Common.
+ (line 2721)
+* unspecified memory: Output Section Data.
+ (line 2821)
+* usage: Options. (line 977)
+* USE_BLX: ARM. (line 4237)
+* using a DEF file: WIN32. (line 4596)
+* using auto-export functionality: WIN32. (line 4579)
+* Using decorations: WIN32. (line 4695)
+* variables, defining: Assignments. (line 2262)
+* verbose: Options. (line 1309)
+* version: Options. (line 641)
+* version script: VERSION. (line 3424)
+* version script, symbol versions: Options. (line 1315)
+* VERSION {script text}: VERSION. (line 3424)
+* versions of symbols: VERSION. (line 3424)
+* VFP11_DENORM_FIX: ARM. (line 4246)
+* warnings, on combining symbols: Options. (line 1322)
+* warnings, on section alignment: Options. (line 1413)
+* warnings, on undefined symbols: Options. (line 1409)
+* weak externals: WIN32. (line 4938)
+* what is this?: Overview. (line 100)
+* wildcard file name patterns: Input Section Wildcards.
+ (line 2616)
+* Xtensa options: Xtensa. (line 5005)
+* Xtensa processors: Xtensa. (line 4956)
+
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