5 * The linker has a new command line option to suppress the generation of any
6 warning or error messages. This can be useful when there is a need to create
7 a known non-working binary. The option is -w or --no-warnings.
9 * ld now supports zstd compressed debug sections. The new option
10 --compress-debug-sections=zstd compresses debug sections with zstd.
12 * Add --enable-default-compressed-debug-sections-algorithm={zlib,zstd}
13 that selects the default compression algorithm
14 for --enable-compressed-debug-sections.
16 * Remove support for -z bndplt (MPX prefix instructions).
20 * The ELF linker will now generate a warning message if the stack is made
21 executable. By default this warning is not issued if the user has
22 specifically requested an executable stack via the "-z execstack"
23 command line option, but the warning can be forced via the new
24 "--warn-execstack" option. Alternatively all warnings about creating
25 an executable stack can be suppressed via the "--no-warn-execstack"
28 In addition the ELF linker will also warn if it creates a memory resident
29 segment with all three of the Read, Write and eXecute permissions set, or
30 if it creates a thread local data segment with the eXecute permission set.
31 These warnings can be disabled via --no-warn-rwx-segments option and
32 re-enabled via the --warn-rwx-segments option.
34 New configure options can also control these new features:
36 --enable-warn-execstack=no
37 will disable the warnings about creating an executable stack.
39 --enable-warn-execstack=yes
40 will make --warn-execstack enabled by default.
42 --enable-warn-rwx-segments=no
43 will make --no-warn-rwx-segments enabled by default.
45 --enable-default-execstack=no
46 will stop the creation of an executable stack simply because an input file
47 is missing a .note.GNU-stack section, even on architectures where this
48 behaviour is the default.
50 * TYPE=<type> is now supported in an output section description to set the
53 * Remove (rudimentary) support for the x86-64 sub-architectures Intel L1OM and
56 * The ELF linker now supports a new --package-metadata option that allows
57 embedding a JSON payload in accordance to the Package Metadata specification.
58 If support for libjansson is enabled at build time, the linker will use it to
59 validate the input. This can be enabled with --enable-jansson.
60 For more details, see: https://systemd.io/ELF_PACKAGE_METADATA/
64 * Add -z pack-relative-relocs/-z no pack-relative-relocs to x86 ELF
65 linker to pack relative relocations in the DT_RELR section.
67 * Add support for the LoongArch architecture.
69 * Add -z indirect-extern-access/-z noindirect-extern-access to x86 ELF
70 linker to control canonical function pointers and copy relocation.
72 * Add --max-cache-size=SIZE to set the the maximum cache size to SIZE
77 * arm-symbianelf support removed.
79 * Add -z report-relative-reloc to x86 ELF linker to report dynamic
82 * Add -z start-stop-gc to disable special treatment of __start_*/__stop_*
83 references when --gc-sections.
85 * Add -Bno-symbolic to cancel -Bsymbolic and -Bsymbolic-functions.
89 * Add libdep plugin, for linking dependencies of static libraries that
90 were recorded by ar in the __.LIBDEP archive member.
92 * Add --error-handling-script=<NAME> command line option to allow a helper
93 script to be invoked when an undefined symbol or a missing library is
94 encountered. This option can be suppressed via the configure time
95 switch: --enable-error-handling-script=no.
97 * Add -z lam-u48 to x86-64 ELF linker to generate LAM_U48 property.
99 * Add -z lam-u57 to x86-64 ELF linker to enerate LAM_U57 property.
101 * Add -z lam-u48-report=[none|warning|error] to report missing LAM_U48
104 * Add -z lam-u57-report=[none|warning|error] to report missing LAM_U57
107 * Add -z lam-report=[none|warning|error] to report missing LAM_U48 and
110 * Add -z x86-64-{baseline|v[234]} to the x86 ELF linker to mark
111 x86-64-{baseline|v[234]} ISA level as needed.
113 * Add -z unique-symbol to avoid duplicated local symbol names.
115 * The creation of PE format DLLs now defaults to using a more secure set of DLL
118 * The linker now deduplicates the types in .ctf sections. The new
119 command-line option --ctf-share-types describes how to do this:
120 its default value, share-unconflicted, produces the most compact
123 * The linker now omits the "variable section" from .ctf sections by
124 default, saving space. This is almost certainly what you want
125 unless you are working on a project that has its own analogue
126 of symbol tables that are not reflected in the ELF symtabs.
128 * Add support for the SHF_GNU_RETAIN ELF section flag.
129 This flag specifies that the section should not be garbage collected by the
134 * X86 NaCl target support is removed.
136 * Add ELF linker command-line options, --export-dynamic-symbol and
137 --export-dynamic-symbol-list, to make symbols dynamic.
139 * Add a configure option, --enable-textrel-check=[no|yes|warning|error],
140 to decide what ELF linker should do by default with DT_TEXTREL in an
141 executable or shared library. Default to yes for Linux/x86 targets.
143 * The -Map=<filename> command line option has been extended so that if
144 <filename> is a directory then <filename>/<output-filename>.map will be
147 * Add a command-line option for ELF linker, --warn-textrel, to warn that
148 DT_TEXTREL is set in a position-independent executable or shared object.
150 * Add command-line options --enable-non-contiguous-regions and
151 --enable-non-contiguous-regions-warnings.
153 * Add command-line option --imagic for the pdp11-aout target to output format
154 IMAGIC (0411) for separate instruction and data spaces, and change the
155 default format option for pdp11-aout to be --omagic.
157 * Relative pathnames in INPUT() and GROUP() directives in linker scripts are
158 searched relative to the directory of the linker script before other search
161 * Add ELF linker command-line option `-z start-stop-visibility=...' to control
162 the visibility of synthetic `__start_SECNAME` and `__stop_SECNAME` symbols.
164 * Add command-line option --dependency-file to write a Make-style dependency
165 file listing the input files consulted by the linker, like the files written
166 by the compiler's -M -MP options.
170 * The ld check for "PHDR segment not covered by LOAD segment" is more
171 effective, catching cases that were wrongly allowed by previous versions of
172 ld. If you see this error it is likely you are linking with a bad linker
173 script or the binary you are building is not intended to be loaded by a
174 dynamic loader. In the latter case --no-dynamic-linker is appropriate.
176 * cr16c support removed.
178 * Add support for z80-elf.
180 * Add support for relocation of each byte or word of multibyte value to Z80
183 * Add support for Zilog eZ80 (both ADL and Z80 mode) and Zilog Z180 CPUs.
187 * Add command-line option --no-print-map-discarded.
189 * The Cortex-A53 Erratum 843419 workaround now supports a choice of which
190 workaround to use. The option --fix-cortex-a53-843419 now takes an
191 optional argument --fix-cortex-a53-843419[=full|adr|adrp] which can be
192 used to force a particular workaround to be used. See --help for AArch64
195 * Add target handlers for AArch64 for ELF GNU program properties.
197 * Add support for GNU_PROPERTY_AARCH64_FEATURE_1_BTI in ELF GNU program
198 properties in the AArch64 ELF linker.
200 * Add support for GNU_PROPERTY_AARCH64_FEATURE_1_PAC in ELF GNU program
201 properties in the AArch64 ELF linker.
203 * Add -z force-bti for AArch64 to enable GNU_PROPERTY_AARCH64_FEATURE_1_BTI
204 on output while warning about missing GNU_PROPERTY_AARCH64_FEATURE_1_BTI
205 on inputs and use PLTs protected with BTI.
207 * Add -z pac-plt for AArch64 to pick PAC enabled PLTs.
211 * Report property change in linker map file when merging GNU properties.
213 * Add support for the C-SKY processor series.
215 * -t now doesn't report members within archives, unless -t is given twice.
216 A single -t is now more useful when generating a list of files that should be
217 packaged for a linker bug report. For example:
218 gcc hello.c -save-temps -Wl,-t | xargs realpath | sort | uniq > files
219 tar cJf test.tar.xz `cat files`
223 * Speed up direct linking with DLLs for Cygwin and Mingw targets.
225 * Add a configure option --enable-separate-code to decide whether
226 -z separate-code should be enabled in ELF linker by default. Default
227 to yes for Linux/x86 targets. Note that -z separate-code can increase
228 disk and memory size.
232 * Add -z separate-code to generate separate code PT_LOAD segment.
234 * Add "-z undefs" command-line option as the inverse of the "-z defs" option.
236 * Add -z globalaudit command-line option to force audit libraries to be run
237 for every dynamic object loaded by an executable - provided that the loader
238 supports this functionality.
240 * Tighten linker script grammar around file name specifiers to prevent the use
241 of SORT_BY_ALIGNMENT and SORT_BY_INIT_PRIORITY on filenames. These would
242 previously be accepted but had no effect.
244 * The EXCLUDE_FILE directive can now be placed within any SORT_* directive
245 within input section lists.
249 * Support for -z shstk in the x86 ELF linker to generate
250 GNU_PROPERTY_X86_FEATURE_1_SHSTK in ELF GNU program properties.
252 * Add support for GNU_PROPERTY_X86_FEATURE_1_SHSTK in ELF GNU program
253 properties in the x86 ELF linker.
255 * Add support for GNU_PROPERTY_X86_FEATURE_1_IBT in ELF GNU program
256 properties in the x86 ELF linker.
258 * Support for -z ibtplt in the x86 ELF linker to generate IBT-enabled
261 * Support for -z ibt in the x86 ELF linker to generate IBT-enabled
262 PLT as well as GNU_PROPERTY_X86_FEATURE_1_IBT in ELF GNU program
265 * Add support for ELF SHF_GNU_MBIND and PT_GNU_MBIND_XXX.
267 * Add support for ELF GNU program properties.
269 * Add support for the Texas Instruments PRU processor.
271 * When configuring for arc*-*-linux* targets the default linker emulation will
272 change if --with-cpu=nps400 is used at configure time.
274 * Improve assignment of LMAs to orphan sections in some edge cases where a
275 mixture of both AT>LMA_REGION and AT(LMA) are used.
277 * Orphan sections placed after an empty section that has an AT(LMA) will now
278 take an load memory address starting from LMA.
280 * Section groups can now be resolved (the group deleted and the group members
281 placed like normal sections) at partial link time either using the new linker
282 option --force-group-allocation or by placing FORCE_GROUP_ALLOCATION into the
287 * The EXCLUDE_FILE linker script construct can now be applied outside of the
288 section list in order for the exclusions to apply over all input sections in
291 * Add support for the RISC-V architecture.
293 * The command-line option --no-eh-frame-hdr can now be used in ELF based
294 linkers to disable the automatic generation of .eh_frame_hdr sections.
296 * Add --in-implib=<infile> to the ARM linker to enable specifying a set of
297 Secure Gateway veneers that must exist in the output import library specified
298 by --out-implib=<outfile> and the address they must have. As such,
299 --in-implib is only supported in combination with --cmse-implib.
301 * Extended the --out-implib=<file> option, previously restricted to x86 PE
302 targets, to any ELF based target. This allows the generation of an import
303 library for an ELF executable, which can then be used by another application
304 to link against the executable.
308 * Add a configure option --enable-relro to decide whether -z relro should
309 be enabled in ELF linker by default. Default to yes for all Linux
310 targets except FRV, HPPA, IA64 and MIPS. Note that -z relro can increase
311 disk and memory size.
313 * Support for -z noreloc-overflow in the x86-64 ELF linker to disable
314 relocation overflow check.
316 * Add -z common/-z nocommon options for ELF targets to control whether to
317 convert common symbols to the STT_COMMON type during a relocatable link.
319 * Support for -z nodynamic-undefined-weak in the x86 ELF linker, which
320 avoids dynamic relocations against undefined weak symbols in executable.
322 * The NOCROSSREFSTO command was added to the linker script language.
324 * Add --no-apply-dynamic-relocs to the AArch64 linker to do not apply link-time
325 values for dynamic relocations.
329 * Add --fix-stm32l4xx-629360 to the ARM linker to enable a link-time
330 workaround for a bug in the bus matrix / memory controller for some of
331 the STM32 Cortex-M4 based products (STM32L4xx)
333 * Add a configure option --enable-compressed-debug-sections={all,ld} to
334 decide whether DWARF debug sections should be compressed by default.
336 * Add support for the ARC EM/HS, and ARC600/700 architectures.
338 * Experimental support for linker garbage collection (--gc-sections)
339 has been enabled for COFF and PE based targets.
341 * New command-line option for ELF targets to compress DWARF debug
342 sections, --compress-debug-sections=[none|zlib|zlib-gnu|zlib-gabi].
344 * New command-line option, --orphan-handling=[place|warn|error|discard], to
345 adjust how orphan sections are handled. The default is 'place' which gives
346 the current behaviour, 'warn' and 'error' issue a warning or error
347 respectively when orphan sections are found, and 'discard' will discard all
350 * Add support for LLVM plugin.
352 * Add --print-memory-usage option to report memory blocks usage.
354 * Add --require-defined option, it's like --undefined except the new symbol
355 must be defined by the end of the link.
359 * PE binaries now once again contain real timestamps by default. To disable
360 the inclusion of a timestamp in a PE binary, use the --no-insert-timestamp
363 * Replace support for openrisc and or32 with support for or1k.
365 * Add support for the --build-id command-line option to COFF based targets.
367 * x86/x86_64 pe-coff now supports the --build-id option.
369 * Add support for the Andes NDS32.
373 * Add LOG2CEIL() builtin function to the linker script language
375 * Add support for the Texas Instruments MSP430X processor.
377 * Add support for Altera Nios II.
379 * Add support for the V850E3V5 architecture.
381 * Add support for the Imagination Technologies Meta processor.
383 * --enable-new-dtags no longer generates old dtags in addition to new dtags.
385 * Remove linker support for MIPS ECOFF targets.
387 * Add ALIGN_WITH_INPUT to the linker script language to force the alignment of
388 an output section to use the maximum alignment of all its input sections.
392 * Enable compressed debug section feature for x86/x86_64 pe-coff.
394 * Add support for the 64-bit ARM architecture: AArch64.
396 * Added SORT_NONE to the linker script language to disable section sorting.
398 * Add a linker-provided symbol when producing ELF output, '__ehdr_start'
399 to point to the ELF file header (and nearby program headers) in the
400 program's memory image.
402 * Add support for S12X processor.
404 * Add support for the VLE extension to the PowerPC architecture.
406 * Add support for the Freescale XGATE architecture.
408 * Add option -f FILE on AIX (for response file).
410 * Add support for the Renesas RL78 architecture.
412 * Add support for the Adapteva EPIPHANY architecture.
416 * --copy-dt-needed-entries is no longer enabled by default. Instead
417 --no-copy-dt-needed-entries is the default.
419 * INPUT_SECTION_FLAGS has been added to the linker script language
420 to allow selection of input sections by section header section flags.
422 * Add support for the Tilera TILEPro and TILE-Gx architectures.
424 * Added SORT_BY_INIT_PRIORITY to the linker script language to permit
425 sorting sections by numerical value of the GCC init_priority attribute
426 encoded in the section name.
430 * Linker script expression evaluation is somewhat more sane. This may
431 break scripts that depend on quirks of the old expression evaluation.
433 * Turn off underscoring for x86_64 PE+-COFF targets. For old behavior the
434 option --enable-leading-mingw64-underscores can be used on configure of
437 * Add support for the TMS320C6000 (TI C6X) processor family.
439 * --add-needed renamed to --copy-dt-needed-entries in order to avoid confusion
440 with --as-needed option.
442 * Extend .def file syntax by '== <ID>' for imports and exports. This allows
443 to alias the import/export table name written in PE image.
445 * Add --exclude-all-symbols option to PE based linkers. This prevents all
446 symbols from automatically being exported.
448 * Add support for the Renesas RX processor.
450 * Add support for alpha-vms target.
454 * GNU/Linux targets now support the STB_GNU_UNIQUE symbol binding. This is a
455 GNU extension to the standard set of ELF symbol bindings. The binding will
456 be passed on to the dynamic linker which will make sure that in the entire
457 process there is just one symbol with the given name and type in use.
459 * PE targets now support a GNU extension to allow the alignment of common
460 common symbols to be specified. This support uses custom options in
461 the .drectve section, which will be disregarded by the native tools.
463 * PE targets now add primitive support for ELF version scripts; symbols
464 are not versioned, but the local and global symbol visibility directives
465 are respected when filtering symbols in auto-export mode.
467 * New option --no-export-dynamic to undo the effect of the -E and
468 --export-dynamic options.
470 * ELF: --warn-alternate-em option to warn if an object has alternate
473 * New script function REGION_ALIAS to add alias names to memory regions.
475 * PE targets no longer make use of the long section names PE extension to
476 the COFF format when generating executable images, by default. The old
477 (slightly non-conformant) behaviour can still be invoked by using the
478 new '--enable-long-section-names' command-line option. It is also enabled
479 automatically in the presence of un-stripped debug information, as GDB
480 needs to be able to find the debug info sections by their full names.
482 * For GNU/Linux systems the linker will now avoid processing any relocations
483 made against symbols of the STT_GNU_IFUNC type and instead emit them into
484 the resulting binary for processing by the loader.
486 * --as-needed now links in a dynamic library if it satisfies undefined
487 symbols in regular objects, or in other dynamic libraries. In the
488 latter case the library is not linked if it is found in a DT_NEEDED
489 entry of one of the libraries already linked.
491 * Add a new command-line option, -Ttext-segment ADDR, for ELF targets
492 to set the address of the first byte of the text segment.
494 * Add support for Sunplus score architecture.
496 * Add new option --use-nul-prefixed-import-tables to ld for PE targets to
497 allow fallback to old import table generation with null element prefix.
499 * Windows PE systems now support a new --exclude-modules-for-implib option,
500 allowing users to partition object files and archive members between a DLL
501 and its associated import library as they are generated during linking.
503 * Add support for Lattice Mico32 (lm32) architecture.
505 * Add CR16 ELF --embedded-relocs (used to embedded relocations into binaries
506 for Embedded-PIC code) option.
508 * Add to the PE/PE+ targets the support of two different kinds of
509 pseudo-relocations. They can be selected by the switches
510 --enable-runtime-pseudo-reloc-v1 and --enable-runtime-pseudo-reloc-v2.
511 For the switch --enable-runtime-pseudo-reloc it uses for 32-bit
512 runtime pseudo relocation version one, for 64-bit the version two.
516 * Linker scripts support a new INSERT command that makes it easier to
517 augment the default script.
519 * Linker script input section filespecs may now specify a file within an
520 archive by writing "archive:file".
522 * The --sort-common switch now has an optional argument which specifies the
523 direction of sorting.
525 * The M68K linker now supports multiple GOT generation schemes controlled via
526 the --got=<type> command-line option.
528 * The ARM EABI linker will now generate stubs for function calls to symbols
529 that are too far away. The placement of the stubs is controlled by a new
530 linker command-line option: --stub-group-size=N.
534 * Linker sources now released under version 3 of the GNU General Public
537 * ELF: New --build-id option to generate a unique per-binary identifier
538 embedded in a note section.
540 * Added support for National Semicondutor CompactRISC (ie CR16) target.
542 * -l:foo now searches the library path for a filename called foo,
543 without converting it to libfoo.a or libfoo.so.
545 * Add a new command-line option '--default-script=FILE' or '-dT FILE'
546 which specifies a replacement for the built in, default linker
549 * ELF: Add -Bsymbolic-functions, --dynamic-list-cpp-new, which puts C++
550 operator new and delete on the dynamic list, and --dynamic-list-data,
551 builtin list for --dynamic-list, which puts global data symbols on the
554 * Add support for x86_64 PE+ target.
556 * Add support for Score target.
558 * ELF: Add --dynamic-list option to specify a list of global symbols
559 whose references shouldn't be bound to the definition within the
560 shared library, or a list of symbols which should be added to the
561 symbol table in the executable.
563 * The default output section LMA has changed for allocatable sections from
564 being equal to VMA, to keeping the difference between LMA and VMA the same as
565 the previous output section in the same region. This is a more useful
566 default when using overlays and other cases where you specify an LMA
567 differing from the VMA for some sections.
569 * New switch: --print-gc-sections to list any sections removed by garabge
572 * ARM: Added --vfp11-denorm-fix option to work around an erratum in current
577 * Support for the Infineon XC16X has been added by KPIT Cummins Infosystems.
579 * Modify the Linux linker search order to better match ld.so search order.
580 Look for DT_NEEDED libraries in paths specified by ld.so.conf before
581 searching the default directories, rather than vice versa.
582 Use $prefix/etc/ld.so.conf if it exists, otherwise /etc/ld.so.conf.
584 * PE-COFF: Forward exports from DLL's can now be specified in .def files
585 passed directly to ld.
587 * Support for the Z80 processor family has been added.
589 * Add support for the "@<file>" syntax to the command line, so that extra
590 switches can be read from <file>.
594 * Support for the R_ARM_V4BX relocation as defined in the ARM AAELF
595 specification has been added via the --fix-v4bx command-line option.
597 * New linker script construct AS_NEEDED(), which sets the --as-needed flag
598 for input files listed inside of it.
600 * A new command-line option, --sysroot, can be used to override the
601 default sysroot location. It only applies to toolchains that were
602 configured using --with-sysroot.
604 * New linker script functions: ORIGIN() and LENGTH() which return information
605 about a specified memory region.
607 * Port to MAXQ processor contributed by HCL Tech.
609 * Added SEGMENT_START to the linker script language to permit the user to
610 override the base address for a segment from the command-line.
612 * ELF: --warn-shared-textrel option to warn if adding a DT_TEXTREL to a shared
615 * Added SORT_BY_NAME and SORT_BY_ALIGNMENT to the linker script
616 language to permit sorting sections by section name or section
619 * Added a new linker command-line switch, --sort-section name|alignment,
620 to sort sections by section name or maximum alignment.
622 * ELF: --add-needed/--no-add-needed options to control if a DT_NEEDED tag
623 should be added when a shared library comes from DT_NEEDED tags.
625 * Support for the crx-elf target added.
627 * Support for the sh-symbianelf target added.
629 * A new linker command-line switch has been added which allows the hash table
630 size to be set to a suitable prime value near to its argument. This switch
631 is --hash-size=<NUMBER>. Also if the switch --reduce-memory-overheads is
632 used, and --hash-size has not been used, then the default value will be set
635 * Linker map files are now generated with an O(N) algorithm for finding symbols
636 that are defined in each section. This uses about 40% more memory for
637 symbols than the old O(N^2) algorithm. You can use the new
638 --reduce-memory-overheads option to select the old algorithm; this option
639 might also be used in the future to select similar tradeoffs.
643 * ELF: --as-needed/--no-as-needed options to control if a DT_NEEDED tag should
644 be added only when a shared library is referenced.
646 * PE: --large-address-aware option to indicate executables support virtual
647 addresses greater than 2 gigabytes.
649 * DWARF 2 support for i386pe added.
651 * The linker script operator DEFINED() will now yield 1 only for a symbol that
652 is defined before the statement where DEFINED is used.
654 * The MIPS --embedded-relocs (used to embed relocations into binaries for
655 Embedded-PIC code) is deprecated and will be removed in a future release.
657 * cr16c support added by NSC.
659 * m32r Linux (ELF) support added by Renesas.
661 * Improved linker's handling of unresolved symbols. The switch
662 --unresolved-symbols=<method> has been added to tell the linker when it
663 should report them and the switch --warn-unresolved-symbols has been added to
664 make reports be issued as warning messages rather than errors.
668 * Added support for Xtensa architecture.
670 * Added --with-sysroot configure switch to specify a target system root, for
671 linking against a target filesystem image.
673 * Added --accept-unknown-linker-format to restore old linker behaviour (pre
674 2.14) of silently accepting and linking in any files in an unknown binary
677 * Added --no-omagic to undo the effects of the -N option.
679 * Support for Texas Instruments TMS320C4x and TMS320C3x series of
680 DSP's contributed by Michael Hayes and Svein E. Seldal.
682 * Added --with-lib-path configure switch to specify default value for
685 * ARM port to QNX operating system added by Graeme Peterson.
687 * IP2K support added by Denis Chertykov.
691 * Support for the Fujitsu FRV architecture added by Red Hat. Models for FR400
694 Changes in version 2.13:
696 * DEC VAX ELF support, by Matt Thomas.
698 Changes in version 2.12:
700 * Support for Don Knuth's MMIX, by Hans-Peter Nilsson.
702 * Support for the OpenRISC 32-bit embedded processor by OpenCores.
704 * Support for -z nocopyreloc in the x86 ELF linker, which disables
705 production of copy relocs. Warning: using this option may result in
706 non-sharable applications.
708 * Support for -z combreloc in the ELF linker, which puts dynamic
709 relocations against the same symbol together, so that dynamic linker
710 can use an one-entry symbol lookup cache.
712 * Support for ELF SHF_MERGE section merging, by Jakub Jelinek.
714 Changes in version 2.11:
716 * Support for AMD x86-64 architecture, by Jan Hubicka, SuSE Labs.
718 * Support added for eliminating duplicate DWARF2 debug information by
719 having the compiler generate the information in sections called
720 .gnu.linkonce.wi.XXXX where XXXX is a checksum for the contents. The
721 linker then merges these sections together into the normal .debug_info
724 * The native ELF linker now searches the directories in DT_RUNPATH or
725 DT_RPATH of a shared library for shared libraries needed by it.
727 * TI C54x support, by Timothy Wall.
729 * Added command-line switch --section-start to set the start address of any
732 * Added ability to emit full relocation information in linked executables,
733 enabled by --emit-relocs. Some post-linkage optimization tools need
734 this information in order to be able to correctly identify and perform
735 symbol relative addressing in the event of changes in section contents
736 (instructions being added or deleted, extending data sections, etc.)
738 * Support for i860, by Jason Eckhardt (preliminary, alpha quality).
740 * Support for CRIS (Axis Communications ETRAX series).
742 * Support for PDP-11 and 2.11BSD a.out format, by Lars Brinkhoff.
744 Changes in version 2.10:
746 * Added AT> to the linker script language to allow load-time allocation of
747 sections into regions.
749 * Added garbage collection of unused sections, enabled by --gc-sections.
750 It does require a bit of backend support; currently implemented are
751 arm-elf, avr-elf, d10v-elf, fr30-elf, i386-elf, m32r-elf, m68k-elf,
752 mcore-elf, mips-elf, mn10300-elf, ppc-elf, sh-elf, sparc-elf, and v850-elf.
753 Others will ignore the option.
755 * Added SORT to the linker script language to permit sorting sections by file
756 name or section name.
758 * Added EXTERN to the linker script language as an equivalent to the -u
761 * Added ASSERT to the linker script language.
763 * Added EXCLUDE_FILE to the linker script language for further control over
766 * Added -O option to optimize linker output (as of this writing, this only
767 affects ELF shared library generation).
769 * The -e option now accepts a number as well as a symbol name.
771 * Added --no-undefined option to disallow undefined symbols when creating a
774 * The linker now issues a warning, not an error, for an undefined symbol when
775 using -Bsymbolic; use the new --no-undefined option to get the old
778 * Added --demangle and --no-demangle options.
780 Changes in version 2.9:
782 * Added SQUAD to the linker script language.
784 * New option --no-warn-mismatch.
786 * The MEMORY command now parses the attributes to determine where sections that
787 are not placed in a specific memory region are placed.
789 Changes in version 2.8:
791 * Linker scripts may now contain shell wildcard characters for file and section
794 * The linker now supports symbol versions in ELF.
796 * The NOCROSSREFS command was added to the linker script language.
798 * The LOADADDR expression was added to the linker script language.
800 * MAX and MIN functions were added to the linker script language.
802 * The OVERLAY construct was added to the linker script language.
804 * New option --warn-section-align to warn when the address of an output section
805 changes due to alignment of an input section.
807 * New options --filter/-F and --auxiliary/-f.
809 Changes in version 2.7:
811 * New option --cref to print out a cross reference table.
813 * New option --wrap SYMBOL.
815 * New option --no-whole-archive, to turn off the effect of --whole-archive.
817 * Input sections assigned to the output section /DISCARD/ in the linker script
818 are not included in the output file.
820 * The SunOS and ELF linkers now merge stabs debugging information which uses
821 the N_BINCL and N_EINCL stab types. This reduces the amount of debugging
822 information generated.
824 Changes in version 2.6:
826 * When an ELF section name is representable as a C identifier (this is not true
827 of most ELF section names), the linker will automatically define symbols
828 __start_SECNAME and __stop_SECNAME, where SECNAME is the section name, at the
829 beginning and the end of the section. This is used by glibc.
831 Addendum: Current versions of the linker (at least for version 2.18 onwards
832 and possibly much earlier as well) place two restrictions on this feature: The
833 symbols are only implemented for orphaned sections, not for explicitly placed
834 sections and they are PROVIDEd rather than being defined.
836 * When an ELF section named .gnu.warning is encountered in an input file, the
837 contents of the section are displayed as an error message, and the section is
838 not copied into the output file. This is used by glibc.
840 * When an ELF section named .gnu.warning.SYMBOL is encountered in an input
841 file, and the symbol SYMBOL is referenced by some object file, the contents of
842 the section are displayed as an error message. The section is not copied into
843 the output file, unless doing a relocatable or shared link. This is used by
846 * New options -split-by-reloc and -split-by-file.
848 * The linker now supports linking PIC compiled code on SPARC SunOS. It can
849 also create SPARC SunOS shared libraries, and, like the native SunOS linker,
850 will do so whenever there is an undefined symbol in the link and neither the -e
851 nor the -r option was used.
853 * The -rpath option may be used on SunOS to set the list of directories to be
854 searched at run time. This overrides the default of building the list from the
857 * The COFF linker now combines debugging information for structs, unions, and
858 enums, so that even if the same type is defined in multiple input files it will
859 only be defined once in the output file. The --traditional-format switch will
860 prevent this optimization.
862 Changes in version 2.5:
864 * The linker now supports linking against SunOS shared libraries. It still can
865 not link SunOS PIC (Position Independent Code) files, so it can not be used to
866 generate shared libraries.
868 * The linker now supports linking against ELF shared libraries for the i386
869 (UnixWare) and SPARC (Solaris). It can also link ELF PIC files, and can be
870 used to generate shared libraries. Shared library generation is not well
871 tested; please report any problems encountered. The linker is now enabled for
874 * Eric Youngdale has contributed Linux support code, including linking against
875 Linux a.out shared libraries. The linker produces Linux QMAGIC binaries.
877 * The ELF backend has been converted to the new linker code. To use the new
878 ELF linker, each particular target requires a relocation function. So far,
879 this function has been written for i386 (UnixWare), SPARC (Solaris) MIPS (Irix
880 5), and HPPA ELF targets.
882 * The -( (--start-group) and -) (--end-group) options have been added to
883 support searching a group of archives as though they were a single archive.
884 This can also be used in a linker script, as GROUP ( files ).
886 * When a file is named on the command line, and the linker does not recognize
887 it as an object file, the linker will now treat the file as a linker script
888 file. A linker script named in this way augments, but does not replace, the
889 default linker script.
891 * The -warn-once option was added. It causes the linker to only warn once per
892 undefined symbol, rather than once per reference.
894 * The COFF backend has been converted to the new linker code. As with ELF, to
895 use the new linker, each particular target requires a relocation function. So
896 far, this function has been written for the i386, m68k, a29k and SH targets.
898 * The -V flag was made a synonym for -v, for SVR4 compatibility. The old -V
899 behaviour is available via --verbose.
901 Changes in version 2.4:
903 * New linker code, by Steve Chamberlain and Ian Taylor. For a.out and ecoff
904 formats (so far), this should result in considerable savings in time
905 and memory used while linking; slightly poorer performance than
906 before for formats not converted yet.
908 * Command-line parsing is no longer done with flex. This means
909 oddball characters in filenames won't get treated as argument
912 * HP-PA ELF support, by Jeff Law. (No SOM support yet.)
914 * Mach i386 support, by David Mackenzie.
916 * Irix 4 shared libraries are now supported (Irix 5 uses ELF, and ELF shared
917 libraries are not yet supported).
919 * COFF shared libraries (as on SCO) should work as well.
921 * The linker is disabled for Solaris. (Actually, it was in 2.3 also, I just
922 forgot to note it.) Some of their C library routines don't work when
923 statically linked, and the GNU linker doesn't support dynamic linking yet.
925 Changes in version 2.3:
927 * Weak symbols are now supported.
929 * ELF support has been added. The linker has been bootstrapped on
930 UnixWare and Solaris.
932 * Alpha OSF/1 support has been added (non dynamic linking only).
934 Changes in version 2.2:
936 * The `bfd' library has been updated to reduce a.out-format string
937 table size. The effect of this is that files linked from many input
938 files with duplicate symbols (`-g' debugging records, or identical
939 static symbols) should be much smaller.
941 Changes in version 2.1:
943 * The ld -ySYMBOL flag (to trace references to SYMBOL) is now implemented.
945 * There is now support for writing ECOFF files, so ld and the
946 other utilities should work on Risc/Ultrix and Irix.
949 Copyright (C) 2012-2023 Free Software Foundation, Inc.
951 Copying and distribution of this file, with or without modification,
952 are permitted in any medium without royalty provided the copyright
953 notice and this notice are preserved.