\input texinfo
@setfilename ld.info
@c Copyright 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000,
-@c 2001, 2002, 2003, 2004, 2005, 2006 Free Software Foundation, Inc.
+@c 2001, 2002, 2003, 2004, 2005, 2006, 2007 Free Software Foundation, Inc.
@syncodeindex ky cp
@c man begin INCLUDE
@include configdoc.texi
@c (configdoc.texi is generated by the Makefile)
-@include ldver.texi
+@include bfdver.texi
@c man end
@c @smallbook
@c Configure for the generation of man pages
@set UsesEnvVars
@set GENERIC
-@set ARC
@set ARM
-@set D10V
-@set D30V
-@set H8/300
-@set H8/500
+@set H8300
@set HPPA
-@set I370
-@set I80386
-@set I860
@set I960
-@set M32R
@set M68HC11
-@set M680X0
-@set MCORE
-@set MIPS
@set MMIX
@set MSP430
-@set PDP11
-@set PJ
@set POWERPC
@set POWERPC64
-@set SH
-@set SPARC
-@set TIC54X
-@set V850
-@set VAX
+@set Renesas
+@set SPU
+@set TICOFF
@set WIN32
@set XTENSA
@end ifset
@end format
@end ifinfo
-@ifinfo
-This file documents the @sc{gnu} linker LD version @value{VERSION}.
-
-Copyright (C) 1991, 92, 93, 94, 95, 96, 97, 98, 99, 2000,
-2001, 2002, 2003, 2004, 2005, 2006 Free Software Foundation, Inc.
+@copying
+This file documents the @sc{gnu} linker LD
+@ifset VERSION_PACKAGE
+@value{VERSION_PACKAGE}
+@end ifset
+version @value{VERSION}.
-@ignore
+Copyright @copyright{} 1991, 92, 93, 94, 95, 96, 97, 98, 99, 2000,
+2001, 2002, 2003, 2004, 2005, 2006, 2007 Free Software Foundation, Inc.
Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.1
with no Invariant Sections, with no Front-Cover Texts, and with no
Back-Cover Texts. A copy of the license is included in the
section entitled ``GNU Free Documentation License''.
-
-Permission is granted to process this file through Tex and print the
-results, provided the printed document carries copying permission
-notice identical to this one except for the removal of this paragraph
-(this paragraph not being relevant to the printed manual).
-
-@end ignore
-@end ifinfo
+@end copying
@iftex
@finalout
@setchapternewpage odd
@titlepage
@title The GNU linker
@sp 1
-@subtitle @code{ld} version 2
+@subtitle @code{ld}
+@ifset VERSION_PACKAGE
+@subtitle @value{VERSION_PACKAGE}
+@end ifset
@subtitle Version @value{VERSION}
@author Steve Chamberlain
@author Ian Lance Taylor
@vskip 0pt plus 1filll
@c man begin COPYRIGHT
Copyright @copyright{} 1991, 92, 93, 94, 95, 96, 97, 98, 99, 2000, 2001,
-2002, 2003, 2004, 2005, 2006 Free Software Foundation, Inc.
+2002, 2003, 2004, 2005, 2006, 2007 Free Software Foundation, Inc.
Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.1
@end titlepage
@end iftex
+@contents
@c FIXME: Talk about importance of *order* of args, cmds to linker!
@ifnottex
@node Top
@top LD
-This file documents the @sc{gnu} linker ld version @value{VERSION}.
+This file documents the @sc{gnu} linker ld
+@ifset VERSION_PACKAGE
+@value{VERSION_PACKAGE}
+@end ifset
+version @value{VERSION}.
This document is distributed under the terms of the GNU Free
Documentation License. A copy of the license is included in the
@ifset POWERPC64
* PowerPC64 ELF64:: ld and PowerPC64 64-bit ELF Support
@end ifset
+@ifset SPU
+* SPU ELF:: ld and SPU ELF Support
+@end ifset
@ifset TICOFF
* TI COFF:: ld and the TI COFF
@end ifset
dynamic object, then you will probably need to use this option when
linking the program itself.
-You can also use the version script to control what symbols should
+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 @samp{--version-script} in @ref{VERSION}.
+See the description of @samp{--dynamic-list}.
@ifclear SingleFormat
@cindex big-endian objects
function to call.
@cindex archive files, from cmd line
-@kindex -l@var{archive}
-@kindex --library=@var{archive}
-@item -l@var{archive}
-@itemx --library=@var{archive}
-Add archive file @var{archive} to the list of files to link. This
-option may be used any number of times. @command{ld} will search its
-path-list for occurrences of @code{lib@var{archive}.a} for every
-@var{archive} specified.
+@kindex -l@var{namespec}
+@kindex --library=@var{namespec}
+@item -l@var{namespec}
+@itemx --library=@var{namespec}
+Add the archive or object file specified by @var{namespec} to the
+list of files to link. This option may be used any number of times.
+If @var{namespec} is of the form @file{:@var{filename}}, @command{ld}
+will search the library path for a file called @var{filename}, otherise it
+will search the library path for a file called @file{lib@var{namespec}.a}.
On systems which support shared libraries, @command{ld} may also search for
-libraries with extensions other than @code{.a}. Specifically, on ELF
-and SunOS systems, @command{ld} will search a directory for a library with
-an extension of @code{.so} before searching for one with an extension of
-@code{.a}. By convention, a @code{.so} extension indicates a shared
-library.
+files other than @file{lib@var{namespec}.a}. Specifically, on ELF
+and SunOS systems, @command{ld} will search a directory for a library
+called @file{lib@var{namespec}.so} before searching for one called
+@file{lib@var{namespec}.a}. (By convention, a @code{.so} extension
+indicates a shared library.) Note that this behavior does not apply
+to @file{:@var{filename}}, which always specifies a file called
+@var{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
specified by any preceding @samp{-L} options. Multiple @samp{-T}
options accumulate.
+@kindex -dT @var{script}
+@kindex --default-script=@var{script}
+@cindex script files
+@item -dT @var{scriptfile}
+@itemx --default-script=@var{scriptfile}
+Use @var{scriptfile} as the default linker script. @xref{Scripts}.
+
+This option is similar to the @option{--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
+@option{--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
+@samp{gcc}).
+
@kindex -u @var{symbol}
@kindex --undefined=@var{symbol}
@cindex undefined symbol
@kindex -X
@kindex --discard-locals
@cindex local symbols, deleting
-@cindex L, deleting symbols beginning
@item -X
@itemx --discard-locals
-Delete all temporary local symbols. For most targets, this is all local
-symbols whose names begin with @samp{L}.
+Delete all temporary local symbols. (These symbols start with
+system-specific local label prefixes, typically @samp{.L} for ELF systems
+or @samp{L} for traditional a.out systems.)
@kindex -y @var{symbol}
@kindex --trace-symbol=@var{symbol}
within the shared library. This option is only meaningful on ELF
platforms which support shared libraries.
+@kindex -Bsymbolic-functions
+@item -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.
+
+@kindex --dynamic-list=@var{dynamic-list-file}
+@item --dynamic-list=@var{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 @ref{VERSION} for more information.
+
+@kindex --dynamic-list-data
+@item --dynamic-list-data
+Include all global data symbols to the dynamic list.
+
+@kindex --dynamic-list-cpp-new
+@item --dynamic-list-cpp-new
+Provide the builtin dynamic list for C++ operator new and delete. It
+is mainly useful for building shared libstdc++.
+
+@kindex --dynamic-list-cpp-typeinfo
+@item --dynamic-list-cpp-typeinfo
+Provide the builtin dynamic list for C++ runtime type identification.
+
@kindex --check-sections
@kindex --no-check-sections
@item --check-sections
@kindex --gc-sections
@kindex --no-gc-sections
@cindex garbage collection
-@item --no-gc-sections
-@itemx --gc-sections
+@item --gc-sections
+@itemx --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 @samp{-r}. The default behaviour (of not performing this garbage
-collection) can be restored by specifying @samp{--no-gc-sections} on
-the command line.
+with @samp{-r} or @samp{--emit-relocs}. The default behaviour (of not
+performing this garbage collection) can be restored by specifying
+@samp{--no-gc-sections} on the command line.
+
+@kindex --print-gc-sections
+@kindex --no-print-gc-sections
+@cindex garbage collection
+@item --print-gc-sections
+@itemx --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 @samp{--gc-sections}) option. The
+default behaviour (of not listing the sections that are removed) can
+be restored by specifying @samp{--no-print-gc-sections} on the command
+line.
@cindex help
@cindex usage
have taken some special action that ensures that the linker errors are
inappropriate.
+@kindex --no-warn-search-mismatch
+@item --no-warn-search-mismatch
+Normally @command{ld} will give a warning if it finds an incompatible
+library during a library search. This option silences the warning.
+
@kindex --no-whole-archive
@item --no-whole-archive
Turn off the effect of the @option{--whole-archive} option for subsequent
@cindex discarding sections
@cindex sections, discarding
@cindex removing sections
-The linker will not create output section which do not have any
-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:
+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:
@smallexample
-.foo @{ *(.foo) @}
+.foo : @{ *(.foo) @}
@end smallexample
@noindent
will only create a @samp{.foo} section in the output file if there is a
-@samp{.foo} section in at least one input file.
+@samp{.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.
-If you use anything other than an input section description as an output
-section command, such as a symbol assignment, then the output section
-will always be created, even if there are no matching input sections.
+The linker will ignore address assignments (@pxref{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.
@cindex /DISCARD/
The special output section name @samp{/DISCARD/} may be used to discard
an output section description sets the VMA (@pxref{Output Section
Address}).
-The linker will normally set the LMA equal to the VMA. You can change
-that by using the @code{AT} keyword. The expression @var{lma} that
-follows the @code{AT} keyword specifies the load address of the
-section.
+The expression @var{lma} that follows the @code{AT} keyword specifies
+the load address of the section.
Alternatively, with @samp{AT>@var{lma_region}} expression, you may
specify a memory region for the section's load address. @xref{MEMORY}.
Note that if the section has not had a VMA assigned to it then the
linker will use the @var{lma_region} as the VMA region as well.
+
+If neither @code{AT} nor @code{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.
@xref{Output Section Region}.
@cindex ROM initialized data
NOCROSSREFS}.
For each section within the @code{OVERLAY}, the linker automatically
-defines two symbols. The symbol @code{__load_start_@var{secname}} is
+provides two symbols. The symbol @code{__load_start_@var{secname}} is
defined as the starting load address of the section. The symbol
@code{__load_stop_@var{secname}} is defined as the final load address of
the section. Any characters within @var{secname} which are not legal
This will define both @samp{.text0} and @samp{.text1} to start at
address 0x1000. @samp{.text0} will be loaded at address 0x4000, and
@samp{.text1} will be loaded immediately after @samp{.text0}. The
-following symbols will be defined: @code{__load_start_text0},
+following symbols will be defined if referenced: @code{__load_start_text0},
@code{__load_stop_text0}, @code{__load_start_text1},
@code{__load_stop_text1}.
@smallexample
@group
.text0 0x1000 : AT (0x4000) @{ o1/*.o(.text) @}
- __load_start_text0 = LOADADDR (.text0);
- __load_stop_text0 = LOADADDR (.text0) + SIZEOF (.text0);
+ PROVIDE (__load_start_text0 = LOADADDR (.text0));
+ PROVIDE (__load_stop_text0 = LOADADDR (.text0) + SIZEOF (.text0));
.text1 0x1000 : AT (0x4000 + SIZEOF (.text0)) @{ o2/*.o(.text) @}
- __load_start_text1 = LOADADDR (.text1);
- __load_stop_text1 = LOADADDR (.text1) + SIZEOF (.text1);
+ PROVIDE (__load_start_text1 = LOADADDR (.text1));
+ PROVIDE (__load_stop_text1 = LOADADDR (.text1) + SIZEOF (.text1));
. = 0x1000 + MAX (SIZEOF (.text0), SIZEOF (.text1));
@end group
@end smallexample
could just as well have appeared in between @samp{1.1} and @samp{1.2}.
However, this would be a confusing way to write a version script.
-Node name can be omited, provided it is the only version node
+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.
@cindex holes
Assigning a value to @code{.} will cause the location counter to be
moved. This may be used to create holes in the output section. The
-location counter may never be moved backwards.
+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.
@smallexample
SECTIONS
The builtin function @code{NEXT} is closely related to @code{ALIGN}.
+@item ALIGNOF(@var{section})
+@kindex ALIGNOF(@var{section})
+@cindex section alignment
+Return the alignment in bytes of the named @var{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 @code{.output} section is stored as the first
+value in that section.
+@smallexample
+@group
+SECTIONS@{ @dots{}
+ .output @{
+ LONG (ALIGNOF (.output))
+ @dots{}
+ @}
+@dots{} @}
+@end group
+@end smallexample
+
@item BLOCK(@var{exp})
@kindex BLOCK(@var{exp})
This is a synonym for @code{ALIGN}, for compatibility with older linker
@ifset POWERPC64
* PowerPC64 ELF64:: @command{ld} and PowerPC64 64-bit ELF Support
@end ifset
+@ifset SPU
+* SPU ELF:: @command{ld} and SPU ELF Support
+@end ifset
@ifset TICOFF
* TI COFF:: @command{ld} and TI COFF
@end ifset
case when a pointer to a function is taken. The pointer will in fact
point to the function trampoline.
+@cindex PIC_VENEER
+@kindex --pic-veneer
+The @samp{--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
+@samp{--emit-relocs} is used to generate relocatable binaries.
+
@ifclear GENERIC
@lowersections
@end ifclear
This option is enabled implicitly for SymbianOS, so there is no need to
specify it if you are using that target.
+@cindex VFP11_DENORM_FIX
+@kindex --vfp11-denorm-fix
+The @samp{--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
+@samp{--vfp-denorm-fix=scalar} if you are using the VFP11 scalar
+mode only, or @samp{--vfp-denorm-fix=vector} if you are using
+vector mode (the latter also works for scalar code). The default is
+@samp{--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.
+
+@cindex NO_ENUM_SIZE_WARNING
+@kindex --no-enum-size-warning
+The @samp{--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.
+
@ifclear GENERIC
@lowersections
@end ifclear
compiled with @samp{-msecure-plt}. @samp{--bss-plt} forces the old
BSS PLT (and GOT layout) which can give slightly better performance.
+@kindex --secure-plt
+@item --secure-plt
+@command{ld} will use the new PLT and GOT layout if it is linking new
+@samp{-fpic} or @samp{-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.
+
@cindex PowerPC GOT
@kindex --sdata-got
@item --sdata-got
@end ifclear
@end ifset
+@ifset SPU
+@ifclear GENERIC
+@raisesections
+@end ifclear
+
+@node SPU ELF
+@section @command{ld} and SPU ELF Support
+
+@cindex SPU ELF options
+@table @option
+
+@cindex SPU plugins
+@kindex --plugin
+@item --plugin
+This option marks an executable as a PIC plugin module.
+
+@cindex SPU overlays
+@kindex --no-overlays
+@item --no-overlays
+Normally, @command{ld} recognizes calls to functions within overlay
+regions, and redirects such calls to an overlay manager via a stub.
+@command{ld} also provides a built-in overlay manager. This option
+turns off all this special overlay handling.
+
+@cindex SPU overlay stub symbols
+@kindex --emit-stub-syms
+@item --emit-stub-syms
+This option causes @command{ld} to label overlay stubs with a local
+symbol that encodes the stub type and destination.
+
+@cindex SPU extra overlay stubs
+@kindex --extra-overlay-stubs
+@item --extra-overlay-stubs
+This option causes @command{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.
+
+@cindex SPU local store size
+@kindex --local-store=lo:hi
+@item --local-store=lo:hi
+@command{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 @option{--local-store=0:0}.
+
+@cindex SPU
+@kindex --stack-analysis
+@item --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,
+@command{ld} will provide an estimate of maximum stack usage.
+@command{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.
+
+@cindex SPU
+@kindex --emit-stack-syms
+@item --emit-stack-syms
+This option, if given along with @option{--stack-analysis} will result
+in @command{ld} emitting stack sizing symbols for each function.
+These take the form @code{__stack_<function_name>} for global
+functions, and @code{__stack_<number>_<function_name>} for static
+functions. @code{<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 @code{STT_NOTYPE}, binding
+@code{STB_LOCAL}, and section @code{SHN_ABS}.
+@end table
+
+@ifclear GENERIC
+@lowersections
+@end ifclear
+@end ifset
+
@ifset TICOFF
@ifclear GENERIC
@raisesections
individuals in the file @file{etc/SERVICE} in the @sc{gnu} Emacs
distribution.
+@ifset BUGURL
Otherwise, send bug reports for @command{ld} to
-@samp{bug-binutils@@gnu.org}.
+@value{BUGURL}.
+@end ifset
The fundamental principle of reporting bugs usefully is this:
@strong{report all the facts}. If you are not sure whether to state a
% Blame: doc@cygnus.com, 28mar91.
@end tex
-
-@contents
@bye
projects / deliverable / binutils-gdb.git / blobdiff