From 36f63dca98ecf5ff67d29eb43114c7061c777a2c Mon Sep 17 00:00:00 2001 From: Nick Clifton Date: Fri, 21 Feb 2003 10:27:06 +0000 Subject: Apply Bob Wilson's linker documenation clean ups. --- ld/ld.texinfo | 981 ++++++++++++++++++++-------------------------------------- 1 file changed, 341 insertions(+), 640 deletions(-) (limited to 'ld/ld.texinfo') diff --git a/ld/ld.texinfo b/ld/ld.texinfo index 62ec58d..d49c4f1 100644 --- a/ld/ld.texinfo +++ b/ld/ld.texinfo @@ -69,7 +69,7 @@ under the terms of the GNU Free Documentation License, Version 1.1 or any later version published by the Free Software Foundation; with no Invariant Sections, with no Front-Cover Texts, and with no Back-Cover Texts. A copy of the license is included in the -section entitled "GNU Free Documentation License". +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 @@ -112,7 +112,7 @@ under the terms of the GNU Free Documentation License, Version 1.1 or any later version published by the Free Software Foundation; with no Invariant Sections, with no Front-Cover Texts, and with no Back-Cover Texts. A copy of the license is included in the -section entitled "GNU Free Documentation License". +section entitled ``GNU Free Documentation License''. @c man end @end titlepage @@ -126,7 +126,7 @@ This file documents the @sc{gnu} linker ld version @value{VERSION}. This document is distributed under the terms of the GNU Free Documentation License. A copy of the license is included in the -section entitled "GNU Free Documentation License". +section entitled ``GNU Free Documentation License''. @menu * Overview:: Overview @@ -145,6 +145,12 @@ section entitled "GNU Free Documentation License". @ifset I960 * i960:: ld and the Intel 960 family @end ifset +@ifset ARM +* ARM:: ld and the ARM family +@end ifset +@ifset HPPA +* HPPA ELF32:: ld and HPPA 32-bit ELF +@end ifset @ifset TICOFF * TI COFF:: ld and the TI COFF @end ifset @@ -280,7 +286,7 @@ and the script command language. If @emph{no} binary input files at all are specified, the linker does not produce any output, and issues the message @samp{No input files}. -If the linker can not recognize the format of an object file, it will +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 @samp{-T}). This feature @@ -298,7 +304,7 @@ option that requires them. For options whose names are multiple letters, either one dash or two can precede the option name; for example, @samp{-trace-symbol} and -@samp{--trace-symbol} are equivalent. Note - there is one exception to +@samp{--trace-symbol} are equivalent. Note---there is one exception to this rule. Multiple letter options that start with a lower case 'o' can only be preceeded by two dashes. This is to reduce confusion with the @samp{-o} option. So for example @samp{-omagic} sets the output file @@ -312,8 +318,8 @@ immediately following the option that requires them. For example, Unique abbreviations of the names of multiple-letter options are accepted. -Note - if the linker is being invoked indirectly, via a compiler driver -(eg @samp{gcc}) then all the linker command line options should be +Note---if the linker is being invoked indirectly, via a compiler driver +(e.g. @samp{gcc}) then all the linker command line options should be prefixed by @samp{-Wl,} (or whatever is appropriate for the particular compiler driver) like this: @@ -458,6 +464,7 @@ You can also use the version script 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}. +@ifclear SingleFormat @cindex big-endian objects @cindex endianness @kindex -EB @@ -468,6 +475,7 @@ Link big-endian objects. This affects the default output format. @kindex -EL @item -EL Link little-endian objects. This affects the default output format. +@end ifclear @kindex -f @kindex --auxiliary @@ -510,11 +518,15 @@ used to select a subset of the symbols provided by the object Some older linkers used the @option{-F} option throughout a compilation toolchain for specifying object-file format for both input and output -object files. The @sc{gnu} linker uses other mechanisms for this -purpose: the @option{-b}, @option{--format}, @option{--oformat} options, the +object files. +@ifclear SingleFormat +The @sc{gnu} linker uses other mechanisms for this purpose: the +@option{-b}, @option{--format}, @option{--oformat} options, the @code{TARGET} command in linker scripts, and the @code{GNUTARGET} -environment variable. The @sc{gnu} linker will ignore the @option{-F} -option when not creating an ELF shared object. +environment variable. +@end ifclear +The @sc{gnu} linker will ignore the @option{-F} option when not +creating an ELF shared object. @cindex finalization function @kindex -fini @@ -1434,7 +1446,7 @@ the linker script being used by the linker. @itemx --version-script=@var{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 heirarchy for the library being created. This option +about the version hierarchy for the library being created. This option is only meaningful on ELF platforms which support shared libraries. @xref{VERSION}. @@ -1625,7 +1637,7 @@ those options are only available for ELF systems. @c man end -@subsection Options specific to i386 PE targets +@subsection Options Specific to i386 PE Targets @c man begin OPTIONS @@ -1667,7 +1679,7 @@ file. @item --enable-stdcall-fixup @itemx --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 +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 @code{_foo} might be linked to the function @@ -1750,27 +1762,27 @@ symbols before they are exported. @kindex --major-image-version @item --major-image-version @var{value} -Sets the major number of the "image version". Defaults to 1. +Sets the major number of the ``image version''. Defaults to 1. @kindex --major-os-version @item --major-os-version @var{value} -Sets the major number of the "os version". Defaults to 4. +Sets the major number of the ``os version''. Defaults to 4. @kindex --major-subsystem-version @item --major-subsystem-version @var{value} -Sets the major number of the "subsystem version". Defaults to 4. +Sets the major number of the ``subsystem version''. Defaults to 4. @kindex --minor-image-version @item --minor-image-version @var{value} -Sets the minor number of the "image version". Defaults to 0. +Sets the minor number of the ``image version''. Defaults to 0. @kindex --minor-os-version @item --minor-os-version @var{value} -Sets the minor number of the "os version". Defaults to 0. +Sets the minor number of the ``os version''. Defaults to 0. @kindex --minor-subsystem-version @item --minor-subsystem-version @var{value} -Sets the minor number of the "subsystem version". Defaults to 0. +Sets the minor number of the ``subsystem version''. Defaults to 0. @cindex DEF files, creating @cindex DLLs, creating @@ -1989,8 +2001,12 @@ subsystem version also. @c man begin ENVIRONMENT You can change the behavior of @command{ld} with the environment variables -@code{GNUTARGET}, @code{LDEMULATION}, and @code{COLLECT_NO_DEMANGLE}. +@ifclear SingleFormat +@code{GNUTARGET}, +@end ifclear +@code{LDEMULATION} and @code{COLLECT_NO_DEMANGLE}. +@ifclear SingleFormat @kindex GNUTARGET @cindex default input format @code{GNUTARGET} determines the input-file object format if you don't @@ -2004,6 +2020,7 @@ 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. +@end ifclear @kindex LDEMULATION @cindex default emulation @@ -2230,7 +2247,7 @@ In this section we describe the simple linker script commands. @end menu @node Entry Point -@subsection Setting the entry point +@subsection Setting the Entry Point @kindex ENTRY(@var{symbol}) @cindex start of execution @cindex first instruction @@ -2259,7 +2276,7 @@ The address @code{0}. @end itemize @node File Commands -@subsection Commands dealing with files +@subsection Commands Dealing with Files @cindex linker script file commands Several linker script commands deal with files. @@ -2346,7 +2363,7 @@ first file. @ifclear SingleFormat @node Format Commands -@subsection Commands dealing with object file formats +@subsection Commands Dealing with Object File Formats A couple of linker script commands deal with object file formats. @table @code @@ -2393,7 +2410,7 @@ command is also used to set the format for the output file. @xref{BFD}. @end ifclear @node Miscellaneous Commands -@subsection Other linker script commands +@subsection Other Linker Script Commands There are a few other linker scripts commands. @table @code @@ -2560,7 +2577,7 @@ If the program references @samp{etext} but does not define it, the linker will use the definition in the linker script. @node SECTIONS -@section SECTIONS command +@section SECTIONS Command @kindex SECTIONS The @code{SECTIONS} command tells the linker how to map input sections into output sections, and how to place the output sections in memory. @@ -2617,7 +2634,7 @@ in the first input file. The first section will be at address zero. @end menu @node Output Section Description -@subsection Output section description +@subsection Output Section Description The full description of an output section looks like this: @smallexample @group @@ -2650,7 +2667,7 @@ a special output section keyword (@pxref{Output Section Keywords}) @end itemize @node Output Section Name -@subsection Output section name +@subsection Output Section Name @cindex name, section @cindex section name The name of the output section is @var{section}. @var{section} must @@ -2668,7 +2685,7 @@ The output section name @samp{/DISCARD/} is special; @ref{Output Section Discarding}. @node Output Section Address -@subsection Output section address +@subsection Output Section Description @cindex address, section @cindex section address The @var{address} is an expression for the VMA (the virtual memory @@ -2715,7 +2732,7 @@ Specifying @var{address} for a section will change the value of the location counter. @node Input Section -@subsection Input section description +@subsection Input Section Description @cindex input sections @cindex mapping input sections to output sections The most common output section command is an input section description. @@ -2734,7 +2751,7 @@ map the input files into your memory layout. @end menu @node Input Section Basics -@subsubsection Input section basics +@subsubsection Input Section Basics @cindex input section basics An input section description consists of a file name optionally followed by a list of section names in parentheses. @@ -2795,7 +2812,7 @@ though it appeared on the command line. Note that this differs from an the archive search path. @node Input Section Wildcards -@subsubsection Input section wildcard patterns +@subsubsection Input Section Wildcard Patterns @cindex input section wildcards @cindex wildcard file name patterns @cindex file name wildcard patterns @@ -2872,7 +2889,7 @@ SECTIONS @{ @end smallexample @node Input Section Common -@subsubsection Input section for common symbols +@subsubsection Input Section for Common Symbols @cindex common symbol placement @cindex uninitialized data placement A special notation is needed for common symbols, because in many object @@ -2908,7 +2925,7 @@ notation is now considered obsolete. It is equivalent to @samp{*(COMMON)}. @node Input Section Keep -@subsubsection Input section and garbage collection +@subsubsection Input Section and Garbage Collection @cindex KEEP @cindex garbage collection When link-time garbage collection is in use (@samp{--gc-sections}), @@ -2918,7 +2935,7 @@ with @code{KEEP()}, as in @code{KEEP(*(.init))} or @code{KEEP(SORT(*)(.ctors))}. @node Input Section Example -@subsubsection Input section example +@subsubsection Input Section Example The following example is a complete linker script. It tells the linker to read all of the sections from file @file{all.o} and place them at the start of output section @samp{outputa} which starts at location @@ -2937,11 +2954,15 @@ SECTIONS @{ all.o foo.o (.input1) @} +@end group +@group outputb : @{ foo.o (.input2) foo1.o (.input1) @} +@end group +@group outputc : @{ *(.input1) @@ -2952,7 +2973,7 @@ SECTIONS @{ @end smallexample @node Output Section Data -@subsection Output section data +@subsection Output Section Data @cindex data @cindex section data @cindex output section data @@ -2992,7 +3013,7 @@ 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 +Note---these commands only work inside a section description and not between them, so the following will produce an error from the linker: @smallexample SECTIONS @{@ .text : @{@ *(.text) @}@ LONG(1) .data : @{@ *(.data) @}@ @}@ @@ -3029,7 +3050,7 @@ precedence. @xref{Output Section Fill}, for details on the fill expression. @node Output Section Keywords -@subsection Output section keywords +@subsection Output Section Keywords There are a couple of keywords which can appear as output section commands. @@ -3108,7 +3129,7 @@ scripts. @end table @node Output Section Discarding -@subsection Output section discarding +@subsection Output Section Discarding @cindex discarding sections @cindex sections, discarding @cindex removing sections @@ -3132,7 +3153,7 @@ input sections. Any input sections which are assigned to an output section named @samp{/DISCARD/} are not included in the output file. @node Output Section Attributes -@subsection Output section attributes +@subsection Output Section Attributes @cindex output section attributes We showed above that the full description of an output section looked like this: @@ -3159,7 +3180,7 @@ remaining section attributes. @end menu @node Output Section Type -@subsubsection Output section type +@subsubsection Output Section Type Each output section may have a type. The type is a keyword in parentheses. The following types are defined: @@ -3196,7 +3217,7 @@ SECTIONS @{ @end smallexample @node Output Section LMA -@subsubsection Output section LMA +@subsubsection Output Section LMA @kindex AT>@var{lma_region} @kindex AT(@var{lma}) @cindex load address @@ -3261,7 +3282,7 @@ for (dst = &_bstart; dst< &_bend; dst++) @end smallexample @node Output Section Region -@subsubsection Output section region +@subsubsection Output Section Region @kindex >@var{region} @cindex section, assigning to memory region @cindex memory regions and sections @@ -3277,7 +3298,7 @@ SECTIONS @{ ROM : @{ *(.text) @} >rom @} @end smallexample @node Output Section Phdr -@subsubsection Output section phdr +@subsubsection Output Section Phdr @kindex :@var{phdr} @cindex section, assigning to program header @cindex program headers and sections @@ -3297,7 +3318,7 @@ SECTIONS @{ .text : @{ *(.text) @} :text @} @end smallexample @node Output Section Fill -@subsubsection Output section fill +@subsubsection Output Section Fill @kindex =@var{fillexp} @cindex section fill pattern @cindex fill pattern, entire section @@ -3325,7 +3346,7 @@ SECTIONS @{ .text : @{ *(.text) @} =0x90909090 @} @end smallexample @node Overlay Description -@subsection Overlay description +@subsection Overlay Description @kindex OVERLAY @cindex overlays An overlay description provides an easy way to describe sections which @@ -3439,7 +3460,7 @@ example could have been written identically as follows. @end smallexample @node MEMORY -@section MEMORY command +@section MEMORY Command @kindex MEMORY @cindex memory regions @cindex regions of memory @@ -3857,7 +3878,7 @@ 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. @samp{old_foo}), or you can use the @samp{.symver} directive to +(i.e., @samp{old_foo}), or you can use the @samp{.symver} directive to specifically bind to an external version of the function in question. You can also specify the language in the version script: @@ -3913,20 +3934,20 @@ hexadecimal. The linker considers other integers to be decimal. In addition, you can use the suffixes @code{K} and @code{M} to scale a constant by @c TEXI2ROFF-KILL -@ifinfo +@ifnottex @c END TEXI2ROFF-KILL @code{1024} or @code{1024*1024} @c TEXI2ROFF-KILL -@end ifinfo +@end ifnottex @tex ${\rm 1024}$ or ${\rm 1024}^2$ @end tex @c END TEXI2ROFF-KILL respectively. For example, the following all refer to the same quantity: @smallexample - _fourk_1 = 4K; - _fourk_2 = 4096; - _fourk_3 = 0x1000; +_fourk_1 = 4K; +_fourk_2 = 4096; +_fourk_3 = 0x1000; @end smallexample @node Symbols @@ -3941,8 +3962,8 @@ 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: @smallexample - "SECTION" = 9; - "with a space" = "also with a space" + 10; +"SECTION" = 9; +"with a space" = "also with a space" + 10; @end smallexample Since symbols can contain many non-alphabetic characters, it is safest @@ -4029,7 +4050,7 @@ the @samp{.data} output section itself. The linker recognizes the standard C set of arithmetic operators, with the standard bindings and precedence levels: @c TEXI2ROFF-KILL -@ifinfo +@ifnottex @c END TEXI2ROFF-KILL @smallexample precedence associativity Operators Notes @@ -4051,7 +4072,7 @@ Notes: (1) Prefix operators (2) @xref{Assignments}. @c TEXI2ROFF-KILL -@end ifinfo +@end ifnottex @tex \vskip \baselineskip %"lispnarrowing" is the extra indent used generally for smallexample @@ -4401,15 +4422,23 @@ sections describe them. Machines where @command{ld} has no additional functionality are not listed. @menu -* H8/300:: @code{ld} and the H8/300 -* i960:: @code{ld} and the Intel 960 family -* ARM:: @code{ld} and the ARM family -* HPPA ELF32:: @code{ld} and HPPA 32-bit ELF +@ifset H8300 +* H8/300:: @command{ld} and the H8/300 +@end ifset +@ifset I960 +* i960:: @command{ld} and the Intel 960 family +@end ifset +@ifset ARM +* ARM:: @command{ld} and the ARM family +@end ifset +@ifset HPPA +* HPPA ELF32:: @command{ld} and HPPA 32-bit ELF +@end ifset @ifset MMIX -* MMIX:: @code{ld} and MMIX +* MMIX:: @command{ld} and MMIX @end ifset @ifset MSP430 -* MSP430:: @code{ld} and MSP430 +* MSP430:: @command{ld} and MSP430 @end ifset @ifset TICOFF * TI COFF:: @command{ld} and TI COFF @@ -4420,8 +4449,6 @@ functionality are not listed. @end menu @end ifset -@c FIXME! This could use @raisesections/@lowersections, but there seems to be a conflict -@c between those and node-defaulting. @ifset H8300 @ifclear GENERIC @raisesections @@ -4458,6 +4485,248 @@ top page of memory). @end ifclear @end ifset +@ifclear GENERIC +@ifset Hitachi +@c This stuff is pointless to say unless you're especially concerned +@c with Hitachi chips; don't enable it for generic case, please. +@node Hitachi +@chapter @command{ld} and Other Hitachi Chips + +@command{ld} also supports the H8/300H, the H8/500, and the Hitachi SH. No +special features, commands, or command-line options are required for +these chips. +@end ifset +@end ifclear + +@ifset I960 +@ifclear GENERIC +@raisesections +@end ifclear + +@node i960 +@section @command{ld} and the Intel 960 Family + +@cindex i960 support + +You can use the @samp{-A@var{architecture}} 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 @command{ld} command line included @w{@samp{-ACA}} as +well as @w{@samp{-ltry}}, the linker would look (in its built-in search +paths, and in any paths you specify with @samp{-L}) for a library with +the names + +@smallexample +@group +try +libtry.a +tryca +libtryca.a +@end group +@end smallexample + +@noindent +The first two possibilities would be considered in any event; the last +two are due to the use of @w{@samp{-ACA}}. + +You can meaningfully use @samp{-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 @w{@samp{-l}} +specifies a library. + +@cindex @option{--relax} on i960 +@cindex relaxing on i960 +@command{ld} supports the @samp{--relax} option for the i960 family. If +you specify @samp{--relax}, @command{ld} finds all @code{balx} and +@code{calx} instructions whose targets are within 24 bits, and turns +them into 24-bit program-counter relative @code{bal} and @code{cal} +instructions, respectively. @command{ld} also turns @code{cal} +instructions into @code{bal} instructions when it determines that the +target subroutine is a leaf routine (that is, the target subroutine does +not itself call any subroutines). + +@ifclear GENERIC +@lowersections +@end ifclear +@end ifset + +@ifset ARM +@ifclear GENERIC +@raisesections +@end ifclear + +@node ARM +@section @command{ld}'s Support for Interworking Between ARM and Thumb Code + +@cindex ARM interworking support +@kindex --support-old-code +For the ARM, @command{ld} will generate code stubs to allow functions calls +betweem ARM and Thumb code. These stubs only work with code that has +been compiled and assembled with the @samp{-mthumb-interwork} command +line option. If it is necessary to link with old ARM object files or +libraries, which have not been compiled with the -mthumb-interwork +option then the @samp{--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. + +@cindex thumb entry point +@cindex entry point, thumb +@kindex --thumb-entry=@var{entry} +The @samp{--thumb-entry} switch is a duplicate of the generic +@samp{--entry} switch, in that it sets the program's starting address. +But it also sets the bottom bit of the address, so that it can be +branched to using a BX instruction, and the program will start +executing in Thumb mode straight away. + +@ifclear GENERIC +@lowersections +@end ifclear +@end ifset + +@ifset HPPA +@ifclear GENERIC +@raisesections +@end ifclear + +@node HPPA ELF32 +@section @command{ld} and HPPA 32-bit ELF Support +@cindex HPPA multiple sub-space stubs +@kindex --multi-subspace +When generating a shared library, @command{ld} will by default generate +import stubs suitable for use with a single sub-space application. +The @samp{--multi-subspace} switch causes @command{ld} to generate export +stubs, and different (larger) import stubs suitable for use with +multiple sub-spaces. + +@cindex HPPA stub grouping +@kindex --stub-group-size=@var{N} +Long branch stubs and import/export stubs are placed by @command{ld} in +stub sections located between groups of input sections. +@samp{--stub-group-size} specifies the maximum size of a group of input +sections handled by one stub section. Since branch offsets are signed, +a stub section may serve two groups of input sections, one group before +the stub section, and one group after it. However, when using +conditional branches that require stubs, it may be better (for branch +prediction) that stub sections only serve one group of input sections. +A negative value for @samp{N} chooses this scheme, ensuring that +branches to stubs always use a negative offset. Two special values of +@samp{N} are recognized, @samp{1} and @samp{-1}. These both instruct +@command{ld} to automatically size input section groups for the branch types +detected, with the same behaviour regarding stub placement as other +positive or negative values of @samp{N} respectively. + +Note that @samp{--stub-group-size} does not split input sections. A +single input section larger than the group size specified will of course +create a larger group (of one section). If input sections are too +large, it may not be possible for a branch to reach its stub. + +@ifclear GENERIC +@lowersections +@end ifclear +@end ifset + +@ifset MMIX +@ifclear GENERIC +@raisesections +@end ifclear + +@node MMIX +@section @code{ld} and MMIX +For MMIX, there is a choice of generating @code{ELF} object files or +@code{mmo} object files when linking. The simulator @code{mmix} +understands the @code{mmo} format. The binutils @code{objcopy} utility +can translate between the two formats. + +There is one special section, the @samp{.MMIX.reg_contents} section. +Contents in this section is assumed to correspond to that of global +registers, and symbols referring to it are translated to special symbols, +equal to registers. In a final link, the start address of the +@samp{.MMIX.reg_contents} section corresponds to the first allocated +global register multiplied by 8. Register @code{$255} is not included in +this section; it is always set to the program entry, which is at the +symbol @code{Main} for @code{mmo} files. + +Symbols with the prefix @code{__.MMIX.start.}, for example +@code{__.MMIX.start..text} and @code{__.MMIX.start..data} are special; +there must be only one each, even if they are local. The default linker +script uses these to set the default start address of a section. + +Initial and trailing multiples of zero-valued 32-bit words in a section, +are left out from an mmo file. + +@ifclear GENERIC +@lowersections +@end ifclear +@end ifset + +@ifset MSP430 +@ifclear GENERIC +@raisesections +@end ifclear + +@node MSP430 +@section @code{ld} and MSP430 +For the MSP430 it is possible to select the MPU architecture. The flag @samp{-m [mpu type]} +will select an appropriate linker script for selected MPU type. (To get a list of known MPUs +just pass @samp{-m help} option to the linker). + +@cindex MSP430 extra sections +The linker will recognize some extra sections which are MSP430 specific: + +@table @code +@item @samp{.vectors} +Defines a portion of ROM where interrupt vectors located. + +@item @samp{.bootloader} +Defines the bootloader portion of the ROM (if applicable). Any code +in this section will be uploaded to the MPU. + +@item @samp{.infomem} +Defines an information memory section (if applicable). Any code in +this section will be uploaded to the MPU. + +@item @samp{.infomemnobits} +This is the same as the @samp{.infomem} section except that any code +in this section will not be uploaded to the MPU. + +@item @samp{.noinit} +Denotes a portion of RAM located above @samp{.bss} section. + +The last two sections are used by gcc. +@end table + +@ifclear GENERIC +@lowersections +@end ifclear +@end ifset + +@ifset TICOFF +@ifclear GENERIC +@raisesections +@end ifclear + +@node TI COFF +@section @command{ld}'s Support for Various TI COFF Versions +@cindex TI COFF versions +@kindex --format=@var{version} +The @samp{--format} switch allows selection of one of the various +TI COFF versions. The latest of this writing is 2; versions 0 and 1 are +also supported. The TI COFF versions also vary in header byte-order +format; @command{ld} will read any version or byte order, but the output +header format depends on the default specified by the specific target. + +@ifclear GENERIC +@lowersections +@end ifclear +@end ifset + @ifset WIN32 @ifclear GENERIC @raisesections @@ -4808,212 +5077,6 @@ which is probably not what you wanted. @end ifclear @end ifset -@ifclear GENERIC -@ifset Hitachi -@c This stuff is pointless to say unless you're especially concerned -@c with Hitachi chips; don't enable it for generic case, please. -@node Hitachi -@chapter @command{ld} and other Hitachi chips - -@command{ld} also supports the H8/300H, the H8/500, and the Hitachi SH. No -special features, commands, or command-line options are required for -these chips. -@end ifset -@end ifclear - -@ifset I960 -@ifclear GENERIC -@raisesections -@end ifclear - -@node i960 -@section @command{ld} and the Intel 960 family - -@cindex i960 support - -You can use the @samp{-A@var{architecture}} 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 @command{ld} command line included @w{@samp{-ACA}} as -well as @w{@samp{-ltry}}, the linker would look (in its built-in search -paths, and in any paths you specify with @samp{-L}) for a library with -the names - -@smallexample -@group -try -libtry.a -tryca -libtryca.a -@end group -@end smallexample - -@noindent -The first two possibilities would be considered in any event; the last -two are due to the use of @w{@samp{-ACA}}. - -You can meaningfully use @samp{-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 @w{@samp{-l}} -specifies a library. - -@cindex @option{--relax} on i960 -@cindex relaxing on i960 -@command{ld} supports the @samp{--relax} option for the i960 family. If -you specify @samp{--relax}, @command{ld} finds all @code{balx} and -@code{calx} instructions whose targets are within 24 bits, and turns -them into 24-bit program-counter relative @code{bal} and @code{cal} -instructions, respectively. @command{ld} also turns @code{cal} -instructions into @code{bal} instructions when it determines that the -target subroutine is a leaf routine (that is, the target subroutine does -not itself call any subroutines). - -@ifclear GENERIC -@lowersections -@end ifclear -@end ifset - -@ifclear GENERIC -@raisesections -@end ifclear - -@node ARM -@section @command{ld}'s support for interworking between ARM and Thumb code - -@cindex ARM interworking support -@kindex --support-old-code -For the ARM, @command{ld} will generate code stubs to allow functions calls -betweem ARM and Thumb code. These stubs only work with code that has -been compiled and assembled with the @samp{-mthumb-interwork} command -line option. If it is necessary to link with old ARM object files or -libraries, which have not been compiled with the -mthumb-interwork -option then the @samp{--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. - -@cindex thumb entry point -@cindex entry point, thumb -@kindex --thumb-entry=@var{entry} -The @samp{--thumb-entry} switch is a duplicate of the generic -@samp{--entry} switch, in that it sets the program's starting address. -But it also sets the bottom bit of the address, so that it can be -branched to using a BX instruction, and the program will start -executing in Thumb mode straight away. - -@node HPPA ELF32 -@section @command{ld} and HPPA 32-bit ELF support -@cindex HPPA multiple sub-space stubs -@kindex --multi-subspace -When generating a shared library, @command{ld} will by default generate -import stubs suitable for use with a single sub-space application. -The @samp{--multi-subspace} switch causes @command{ld} to generate export -stubs, and different (larger) import stubs suitable for use with -multiple sub-spaces. - -@cindex HPPA stub grouping -@kindex --stub-group-size=@var{N} -Long branch stubs and import/export stubs are placed by @command{ld} in -stub sections located between groups of input sections. -@samp{--stub-group-size} specifies the maximum size of a group of input -sections handled by one stub section. Since branch offsets are signed, -a stub section may serve two groups of input sections, one group before -the stub section, and one group after it. However, when using -conditional branches that require stubs, it may be better (for branch -prediction) that stub sections only serve one group of input sections. -A negative value for @samp{N} chooses this scheme, ensuring that -branches to stubs always use a negative offset. Two special values of -@samp{N} are recognized, @samp{1} and @samp{-1}. These both instruct -@command{ld} to automatically size input section groups for the branch types -detected, with the same behaviour regarding stub placement as other -positive or negative values of @samp{N} respectively. - -Note that @samp{--stub-group-size} does not split input sections. A -single input section larger than the group size specified will of course -create a larger group (of one section). If input sections are too -large, it may not be possible for a branch to reach its stub. - -@ifset MMIX -@node MMIX -@section @code{ld} and MMIX -For MMIX, there is choice of generating @code{ELF} object files or -@code{mmo} object files when linking. The simulator @code{mmix} -understands the @code{mmo} format. The binutils @code{objcopy} utility -can translate between the two formats. - -There is one special section, the @samp{.MMIX.reg_contents} section. -Contents in this section is assumed to correspond to that of global -registers, and symbols referring to it are translated to special symbols, -equal to registers. In a final link, the start address of the -@samp{.MMIX.reg_contents} section corresponds to the first allocated -global register multiplied by 8. Register @code{$255} is not included in -this section; it is always set to the program entry, which is at the -symbol @code{Main} for @code{mmo} files. - -Symbols with the prefix @code{__.MMIX.start.}, for example -@code{__.MMIX.start..text} and @code{__.MMIX.start..data} are special; -there must be only one each, even if they are local. The default linker -script uses these to set the default start address of a section. - -Initial and trailing multiples of zero-valued 32-bit words in a section, -are left out from an mmo file. -@end ifset - -@ifset MSP430 -@node MSP430 -@section @code{ld} and MSP430 -For the MSP430 it is possible to select the MPU architecture. The flag @samp{-m [mpu type]} -will select an appropriate linker script for selected MPU type. (To get a list of known MPUs -just pass @samp{-m help} option to the linker). - -@cindex MSP430 extra sections -The linker will recognize some extra sections which are MSP430 specific: - -@table @code -@item @samp{.vectors} -Defines a portion of ROM where interrupt vectors located. - -@item @samp{.bootloader} -Defines the bootloader portion of the ROM (if applicable). Any code -in this section will be uploaded to the MPU. - -@item @samp{.infomem} -Defines an information memory section (if applicable). Any code in -this section will be uploaded to the MPU. - -@item @samp{.infomemnobits} -This is the same as the @samp{.infomem} section except that any code -in this section will not be uploaded to the MPU. - -@item @samp{.noinit} -Denotes a portion of RAM located above @samp{.bss} section. - -The last two sections are used by gcc. -@end table -@end ifset - -@ifset TICOFF -@node TI COFF -@section @command{ld}'s support for various TI COFF versions -@cindex TI COFF versions -@kindex --format=@var{version} -The @samp{--format} switch allows selection of one of the various -TI COFF versions. The latest of this writing is 2; versions 0 and 1 are -also supported. The TI COFF versions also vary in header byte-order -format; @command{ld} will read any version or byte order, but the output -header format depends on the default specified by the specific target. -@end ifset - -@ifclear GENERIC -@lowersections -@end ifclear - @ifclear SingleFormat @node BFD @chapter BFD @@ -5052,7 +5115,7 @@ conversion and during output. @xref{BFD information loss}. @end menu @node BFD outline -@section How it works: an outline of BFD +@section How It Works: An Outline of BFD @cindex opening object files @include bfdsumm.texi @end ifclear @@ -5079,7 +5142,7 @@ information that enables us to fix the bug. @end menu @node Bug Criteria -@section Have you found a bug? +@section Have You Found a Bug? @cindex bug criteria If you are not sure whether you have found a bug, here are some guidelines: @@ -5108,7 +5171,7 @@ improvement of @command{ld} are welcome in any case. @end itemize @node Bug Reporting -@section How to report bugs +@section How to Report Bugs @cindex bug reports @cindex @command{ld} bugs, reporting @@ -5143,9 +5206,9 @@ the bug if it is new to us. Therefore, always write your bug reports on the assumption that the bug has not been reported previously. Sometimes people give a few sketchy facts and ask, ``Does this ring a -bell?'' Those bug reports are useless, and we urge everyone to -@emph{refuse to respond to them} except to chide the sender to report -bugs properly. +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: @@ -5404,369 +5467,7 @@ If you have more than one @code{SECT} statement for the same @var{secname}, only the @emph{first} sets the start address. @end table -@node GNU Free Documentation License -@appendix GNU Free Documentation License -@cindex GNU Free Documentation License - - GNU Free Documentation License - - Version 1.1, March 2000 - - Copyright (C) 2000 Free Software Foundation, Inc. - 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA - - Everyone is permitted to copy and distribute verbatim copies - of this license document, but changing it is not allowed. - - -0. PREAMBLE - -The purpose of this License is to make a manual, textbook, or other -written document "free" in the sense of freedom: to assure everyone -the effective freedom to copy and redistribute it, with or without -modifying it, either commercially or noncommercially. Secondarily, -this License preserves for the author and publisher a way to get -credit for their work, while not being considered responsible for -modifications made by others. - -This License is a kind of "copyleft", which means that derivative -works of the document must themselves be free in the same sense. It -complements the GNU General Public License, which is a copyleft -license designed for free software. - -We have designed this License in order to use it for manuals for free -software, because free software needs free documentation: a free -program should come with manuals providing the same freedoms that the -software does. But this License is not limited to software manuals; -it can be used for any textual work, regardless of subject matter or -whether it is published as a printed book. We recommend this License -principally for works whose purpose is instruction or reference. - - -1. 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TRANSLATION - -Translation is considered a kind of modification, so you may -distribute translations of the Document under the terms of section 4. -Replacing Invariant Sections with translations requires special -permission from their copyright holders, but you may include -translations of some or all Invariant Sections in addition to the -original versions of these Invariant Sections. You may include a -translation of this License provided that you also include the -original English version of this License. In case of a disagreement -between the translation and the original English version of this -License, the original English version will prevail. - - -9. TERMINATION - -You may not copy, modify, sublicense, or distribute the Document except -as expressly provided for under this License. Any other attempt to -copy, modify, sublicense or distribute the Document is void, and will -automatically terminate your rights under this License. However, -parties who have received copies, or rights, from you under this -License will not have their licenses terminated so long as such -parties remain in full compliance. - - -10. FUTURE REVISIONS OF THIS LICENSE - -The Free Software Foundation may publish new, revised versions -of the GNU Free Documentation License from time to time. Such new -versions will be similar in spirit to the present version, but may -differ in detail to address new problems or concerns. See -http://www.gnu.org/copyleft/. - -Each version of the License is given a distinguishing version number. -If the Document specifies that a particular numbered version of this -License "or any later version" applies to it, you have the option of -following the terms and conditions either of that specified version or -of any later version that has been published (not as a draft) by the -Free Software Foundation. If the Document does not specify a version -number of this License, you may choose any version ever published (not -as a draft) by the Free Software Foundation. - - -ADDENDUM: How to use this License for your documents - -To use this License in a document you have written, include a copy of -the License in the document and put the following copyright and -license notices just after the title page: - -@smallexample - Copyright (c) YEAR YOUR NAME. - Permission is granted to copy, distribute and/or modify this document - under the terms of the GNU Free Documentation License, Version 1.1 - or any later version published by the Free Software Foundation; - with the Invariant Sections being LIST THEIR TITLES, with the - Front-Cover Texts being LIST, and with the Back-Cover Texts being LIST. - A copy of the license is included in the section entitled "GNU - Free Documentation License". -@end smallexample - -If you have no Invariant Sections, write "with no Invariant Sections" -instead of saying which ones are invariant. If you have no -Front-Cover Texts, write "no Front-Cover Texts" instead of -"Front-Cover Texts being LIST"; likewise for Back-Cover Texts. - -If your document contains nontrivial examples of program code, we -recommend releasing these examples in parallel under your choice of -free software license, such as the GNU General Public License, -to permit their use in free software. +@include fdl.texi @node Index @unnumbered Index -- cgit v1.1