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1 -*- text -*-
2
3 * Add libdep plugin, for linking dependencies of static libraries that
4 were recorded by ar in the __.LIBDEP archive member.
5
6 * Add --error-handling-script=<NAME> command line option to allow a helper
7 script to be invoked when an undefined symbol or a missing library is
8 encountered. This option can be suppressed via the configure time
9 switch: --enable-error-handling-script=no.
10
11 * Add -z lam-u48 to x86-64 ELF linker to generate LAM_U48 property.
12
13 * Add -z lam-u57 to x86-64 ELF linker to enerate LAM_U57 property.
14
15 * Add -z lam-u48-report=[none|warning|error] to report missing LAM_U48
16 property.
17
18 * Add -z lam-u57-report=[none|warning|error] to report missing LAM_U57
19 property.
20
21 * Add -z lam-report=[none|warning|error] to report missing LAM_U48 and
22 LAM_U57 properties.
23
24 * Add -z x86-64-{baseline|v[234]} to the x86 ELF linker to mark
25 x86-64-{baseline|v[234]} ISA level as needed.
26
27 * Add -z unique-symbol to avoid duplicated local symbol names.
28
29 * The creation of PE format DLLs now defaults to using a more secure set of DLL
30 characteristics.
31
32 * The linker now deduplicates the types in .ctf sections. The new
33 command-line option --ctf-share-types describes how to do this:
34 its default value, share-unconflicted, produces the most compact
35 output.
36
37 * The linker now omits the "variable section" from .ctf sections by
38 default, saving space. This is almost certainly what you want
39 unless you are working on a project that has its own analogue
40 of symbol tables that are not reflected in the ELF symtabs.
41
42 * Add support for the SHF_GNU_RETAIN ELF section flag.
43 This flag specifies that the section should not be garbage collected by the
44 linker.
45
46 Changes in 2.35:
47
48 * X86 NaCl target support is removed.
49
50 * Add ELF linker command-line options, --export-dynamic-symbol and
51 --export-dynamic-symbol-list, to make symbols dynamic.
52
53 * Add a configure option, --enable-textrel-check=[no|yes|warning|error],
54 to decide what ELF linker should do by default with DT_TEXTREL in an
55 executable or shared library. Default to yes for Linux/x86 targets.
56
57 * The -Map=<filename> command line option has been extended so that if
58 <filename> is a directory then <filename>/<output-filename>.map will be
59 created.
60
61 * Add a command-line option for ELF linker, --warn-textrel, to warn that
62 DT_TEXTREL is set in a position-independent executable or shared object.
63
64 * Add command-line options --enable-non-contiguous-regions and
65 --enable-non-contiguous-regions-warnings.
66
67 * Add command-line option --imagic for the pdp11-aout target to output format
68 IMAGIC (0411) for separate instruction and data spaces, and change the
69 default format option for pdp11-aout to be --omagic.
70
71 * Relative pathnames in INPUT() and GROUP() directives in linker scripts are
72 searched relative to the directory of the linker script before other search
73 paths.
74
75 * Add ELF linker command-line option `-z start-stop-visibility=...' to control
76 the visibility of synthetic `__start_SECNAME` and `__stop_SECNAME` symbols.
77
78 * Add command-line option --dependency-file to write a Make-style dependency
79 file listing the input files consulted by the linker, like the files written
80 by the compiler's -M -MP options.
81
82 Changes in 2.34:
83
84 * The ld check for "PHDR segment not covered by LOAD segment" is more
85 effective, catching cases that were wrongly allowed by previous versions of
86 ld. If you see this error it is likely you are linking with a bad linker
87 script or the binary you are building is not intended to be loaded by a
88 dynamic loader. In the latter case --no-dynamic-linker is appropriate.
89
90 * cr16c support removed.
91
92 * Add support for z80-elf.
93
94 * Add support for relocation of each byte or word of multibyte value to Z80
95 targets.
96
97 * Add support for Zilog eZ80 (both ADL and Z80 mode) and Zilog Z180 CPUs.
98
99 Changes in 2.33:
100
101 * Add command-line option --no-print-map-discarded.
102
103 * The Cortex-A53 Erratum 843419 workaround now supports a choice of which
104 workaround to use. The option --fix-cortex-a53-843419 now takes an
105 optional argument --fix-cortex-a53-843419[=full|adr|adrp] which can be
106 used to force a particular workaround to be used. See --help for AArch64
107 for more details.
108
109 * Add target handlers for AArch64 for ELF GNU program properties.
110
111 * Add support for GNU_PROPERTY_AARCH64_FEATURE_1_BTI in ELF GNU program
112 properties in the AArch64 ELF linker.
113
114 * Add support for GNU_PROPERTY_AARCH64_FEATURE_1_PAC in ELF GNU program
115 properties in the AArch64 ELF linker.
116
117 * Add -z force-bti for AArch64 to enable GNU_PROPERTY_AARCH64_FEATURE_1_BTI
118 on output while warning about missing GNU_PROPERTY_AARCH64_FEATURE_1_BTI
119 on inputs and use PLTs protected with BTI.
120
121 * Add -z pac-plt for AArch64 to pick PAC enabled PLTs.
122
123 Changes in 2.32:
124
125 * Report property change in linker map file when merging GNU properties.
126
127 * Add support for the C-SKY processor series.
128
129 * -t now doesn't report members within archives, unless -t is given twice.
130 A single -t is now more useful when generating a list of files that should be
131 packaged for a linker bug report. For example:
132 gcc hello.c -save-temps -Wl,-t | xargs realpath | sort | uniq > files
133 tar cJf test.tar.xz `cat files`
134
135 Changes in 2.31:
136
137 * Speed up direct linking with DLLs for Cygwin and Mingw targets.
138
139 * Add a configure option --enable-separate-code to decide whether
140 -z separate-code should be enabled in ELF linker by default. Default
141 to yes for Linux/x86 targets. Note that -z separate-code can increase
142 disk and memory size.
143
144 Changes in 2.30:
145
146 * Add -z separate-code to generate separate code PT_LOAD segment.
147
148 * Add "-z undefs" command-line option as the inverse of the "-z defs" option.
149
150 * Add -z globalaudit command-line option to force audit libraries to be run
151 for every dynamic object loaded by an executable - provided that the loader
152 supports this functionality.
153
154 * Tighten linker script grammar around file name specifiers to prevent the use
155 of SORT_BY_ALIGNMENT and SORT_BY_INIT_PRIORITY on filenames. These would
156 previously be accepted but had no effect.
157
158 * The EXCLUDE_FILE directive can now be placed within any SORT_* directive
159 within input section lists.
160
161 Changes in 2.29:
162
163 * Support for -z shstk in the x86 ELF linker to generate
164 GNU_PROPERTY_X86_FEATURE_1_SHSTK in ELF GNU program properties.
165
166 * Add support for GNU_PROPERTY_X86_FEATURE_1_SHSTK in ELF GNU program
167 properties in the x86 ELF linker.
168
169 * Add support for GNU_PROPERTY_X86_FEATURE_1_IBT in ELF GNU program
170 properties in the x86 ELF linker.
171
172 * Support for -z ibtplt in the x86 ELF linker to generate IBT-enabled
173 PLT.
174
175 * Support for -z ibt in the x86 ELF linker to generate IBT-enabled
176 PLT as well as GNU_PROPERTY_X86_FEATURE_1_IBT in ELF GNU program
177 properties.
178
179 * Add support for ELF SHF_GNU_MBIND and PT_GNU_MBIND_XXX.
180
181 * Add support for ELF GNU program properties.
182
183 * Add support for the Texas Instruments PRU processor.
184
185 * When configuring for arc*-*-linux* targets the default linker emulation will
186 change if --with-cpu=nps400 is used at configure time.
187
188 * Improve assignment of LMAs to orphan sections in some edge cases where a
189 mixture of both AT>LMA_REGION and AT(LMA) are used.
190
191 * Orphan sections placed after an empty section that has an AT(LMA) will now
192 take an load memory address starting from LMA.
193
194 * Section groups can now be resolved (the group deleted and the group members
195 placed like normal sections) at partial link time either using the new linker
196 option --force-group-allocation or by placing FORCE_GROUP_ALLOCATION into the
197 linker script.
198
199 Changes in 2.28:
200
201 * The EXCLUDE_FILE linker script construct can now be applied outside of the
202 section list in order for the exclusions to apply over all input sections in
203 the list.
204
205 * Add support for the RISC-V architecture.
206
207 * The command-line option --no-eh-frame-hdr can now be used in ELF based
208 linkers to disable the automatic generation of .eh_frame_hdr sections.
209
210 * Add --in-implib=<infile> to the ARM linker to enable specifying a set of
211 Secure Gateway veneers that must exist in the output import library specified
212 by --out-implib=<outfile> and the address they must have. As such,
213 --in-implib is only supported in combination with --cmse-implib.
214
215 * Extended the --out-implib=<file> option, previously restricted to x86 PE
216 targets, to any ELF based target. This allows the generation of an import
217 library for an ELF executable, which can then be used by another application
218 to link against the executable.
219
220 Changes in 2.27:
221
222 * Add a configure option --enable-relro to decide whether -z relro should
223 be enabled in ELF linker by default. Default to yes for all Linux
224 targets except FRV, HPPA, IA64 and MIPS. Note that -z relro can increase
225 disk and memory size.
226
227 * Support for -z noreloc-overflow in the x86-64 ELF linker to disable
228 relocation overflow check.
229
230 * Add -z common/-z nocommon options for ELF targets to control whether to
231 convert common symbols to the STT_COMMON type during a relocatable link.
232
233 * Support for -z nodynamic-undefined-weak in the x86 ELF linker, which
234 avoids dynamic relocations against undefined weak symbols in executable.
235
236 * The NOCROSSREFSTO command was added to the linker script language.
237
238 * Add --no-apply-dynamic-relocs to the AArch64 linker to do not apply link-time
239 values for dynamic relocations.
240
241 Changes in 2.26:
242
243 * Add --fix-stm32l4xx-629360 to the ARM linker to enable a link-time
244 workaround for a bug in the bus matrix / memory controller for some of
245 the STM32 Cortex-M4 based products (STM32L4xx)
246
247 * Add a configure option --enable-compressed-debug-sections={all,ld} to
248 decide whether DWARF debug sections should be compressed by default.
249
250 * Add support for the ARC EM/HS, and ARC600/700 architectures.
251
252 * Experimental support for linker garbage collection (--gc-sections)
253 has been enabled for COFF and PE based targets.
254
255 * New command-line option for ELF targets to compress DWARF debug
256 sections, --compress-debug-sections=[none|zlib|zlib-gnu|zlib-gabi].
257
258 * New command-line option, --orphan-handling=[place|warn|error|discard], to
259 adjust how orphan sections are handled. The default is 'place' which gives
260 the current behaviour, 'warn' and 'error' issue a warning or error
261 respectively when orphan sections are found, and 'discard' will discard all
262 orphan sections.
263
264 * Add support for LLVM plugin.
265
266 * Add --print-memory-usage option to report memory blocks usage.
267
268 * Add --require-defined option, it's like --undefined except the new symbol
269 must be defined by the end of the link.
270
271 Changes in 2.25:
272
273 * PE binaries now once again contain real timestamps by default. To disable
274 the inclusion of a timestamp in a PE binary, use the --no-insert-timestamp
275 command-line option.
276
277 * Replace support for openrisc and or32 with support for or1k.
278
279 * Add support for the --build-id command-line option to COFF based targets.
280
281 * x86/x86_64 pe-coff now supports the --build-id option.
282
283 * Add support for the Andes NDS32.
284
285 Changes in 2.24:
286
287 * Add LOG2CEIL() builtin function to the linker script language
288
289 * Add support for the Texas Instruments MSP430X processor.
290
291 * Add support for Altera Nios II.
292
293 * Add support for the V850E3V5 architecture.
294
295 * Add support for the Imagination Technologies Meta processor.
296
297 * --enable-new-dtags no longer generates old dtags in addition to new dtags.
298
299 * Remove linker support for MIPS ECOFF targets.
300
301 * Add ALIGN_WITH_INPUT to the linker script language to force the alignment of
302 an output section to use the maximum alignment of all its input sections.
303
304 Changes in 2.23:
305
306 * Enable compressed debug section feature for x86/x86_64 pe-coff.
307
308 * Add support for the 64-bit ARM architecture: AArch64.
309
310 * Added SORT_NONE to the linker script language to disable section sorting.
311
312 * Add a linker-provided symbol when producing ELF output, '__ehdr_start'
313 to point to the ELF file header (and nearby program headers) in the
314 program's memory image.
315
316 * Add support for S12X processor.
317
318 * Add support for the VLE extension to the PowerPC architecture.
319
320 * Add support for the Freescale XGATE architecture.
321
322 * Add option -f FILE on AIX (for response file).
323
324 * Add support for the Renesas RL78 architecture.
325
326 * Add support for the Adapteva EPIPHANY architecture.
327
328 Changes in 2.22:
329
330 * --copy-dt-needed-entries is no longer enabled by default. Instead
331 --no-copy-dt-needed-entries is the default.
332
333 * INPUT_SECTION_FLAGS has been added to the linker script language
334 to allow selection of input sections by section header section flags.
335
336 * Add support for the Tilera TILEPro and TILE-Gx architectures.
337
338 * Added SORT_BY_INIT_PRIORITY to the linker script language to permit
339 sorting sections by numerical value of the GCC init_priority attribute
340 encoded in the section name.
341
342 Changes in 2.21:
343
344 * Linker script expression evaluation is somewhat more sane. This may
345 break scripts that depend on quirks of the old expression evaluation.
346
347 * Turn off underscoring for x86_64 PE+-COFF targets. For old behavior the
348 option --enable-leading-mingw64-underscores can be used on configure of
349 bfd.
350
351 * Add support for the TMS320C6000 (TI C6X) processor family.
352
353 * --add-needed renamed to --copy-dt-needed-entries in order to avoid confusion
354 with --as-needed option.
355
356 * Extend .def file syntax by '== <ID>' for imports and exports. This allows
357 to alias the import/export table name written in PE image.
358
359 * Add --exclude-all-symbols option to PE based linkers. This prevents all
360 symbols from automatically being exported.
361
362 * Add support for the Renesas RX processor.
363
364 * Add support for alpha-vms target.
365
366 Changes in 2.20:
367
368 * GNU/Linux targets now support the STB_GNU_UNIQUE symbol binding. This is a
369 GNU extension to the standard set of ELF symbol bindings. The binding will
370 be passed on to the dynamic linker which will make sure that in the entire
371 process there is just one symbol with the given name and type in use.
372
373 * PE targets now support a GNU extension to allow the alignment of common
374 common symbols to be specified. This support uses custom options in
375 the .drectve section, which will be disregarded by the native tools.
376
377 * PE targets now add primitive support for ELF version scripts; symbols
378 are not versioned, but the local and global symbol visibility directives
379 are respected when filtering symbols in auto-export mode.
380
381 * New option --no-export-dynamic to undo the effect of the -E and
382 --export-dynamic options.
383
384 * ELF: --warn-alternate-em option to warn if an object has alternate
385 ELF machine code.
386
387 * New script function REGION_ALIAS to add alias names to memory regions.
388
389 * PE targets no longer make use of the long section names PE extension to
390 the COFF format when generating executable images, by default. The old
391 (slightly non-conformant) behaviour can still be invoked by using the
392 new '--enable-long-section-names' command-line option. It is also enabled
393 automatically in the presence of un-stripped debug information, as GDB
394 needs to be able to find the debug info sections by their full names.
395
396 * For GNU/Linux systems the linker will now avoid processing any relocations
397 made against symbols of the STT_GNU_IFUNC type and instead emit them into
398 the resulting binary for processing by the loader.
399
400 * --as-needed now links in a dynamic library if it satisfies undefined
401 symbols in regular objects, or in other dynamic libraries. In the
402 latter case the library is not linked if it is found in a DT_NEEDED
403 entry of one of the libraries already linked.
404
405 * Add a new command-line option, -Ttext-segment ADDR, for ELF targets
406 to set the address of the first byte of the text segment.
407
408 * Add support for Sunplus score architecture.
409
410 * Add new option --use-nul-prefixed-import-tables to ld for PE targets to
411 allow fallback to old import table generation with null element prefix.
412
413 * Windows PE systems now support a new --exclude-modules-for-implib option,
414 allowing users to partition object files and archive members between a DLL
415 and its associated import library as they are generated during linking.
416
417 * Add support for Lattice Mico32 (lm32) architecture.
418
419 * Add CR16 ELF --embedded-relocs (used to embedded relocations into binaries
420 for Embedded-PIC code) option.
421
422 * Add to the PE/PE+ targets the support of two different kinds of
423 pseudo-relocations. They can be selected by the switches
424 --enable-runtime-pseudo-reloc-v1 and --enable-runtime-pseudo-reloc-v2.
425 For the switch --enable-runtime-pseudo-reloc it uses for 32-bit
426 runtime pseudo relocation version one, for 64-bit the version two.
427
428 Changes in 2.19:
429
430 * Linker scripts support a new INSERT command that makes it easier to
431 augment the default script.
432
433 * Linker script input section filespecs may now specify a file within an
434 archive by writing "archive:file".
435
436 * The --sort-common switch now has an optional argument which specifies the
437 direction of sorting.
438
439 * The M68K linker now supports multiple GOT generation schemes controlled via
440 the --got=<type> command-line option.
441
442 * The ARM EABI linker will now generate stubs for function calls to symbols
443 that are too far away. The placement of the stubs is controlled by a new
444 linker command-line option: --stub-group-size=N.
445
446 Changes in 2.18:
447
448 * Linker sources now released under version 3 of the GNU General Public
449 License.
450
451 * ELF: New --build-id option to generate a unique per-binary identifier
452 embedded in a note section.
453
454 * Added support for National Semicondutor CompactRISC (ie CR16) target.
455
456 * -l:foo now searches the library path for a filename called foo,
457 without converting it to libfoo.a or libfoo.so.
458
459 * Add a new command-line option '--default-script=FILE' or '-dT FILE'
460 which specifies a replacement for the built in, default linker
461 script.
462
463 * ELF: Add -Bsymbolic-functions, --dynamic-list-cpp-new, which puts C++
464 operator new and delete on the dynamic list, and --dynamic-list-data,
465 builtin list for --dynamic-list, which puts global data symbols on the
466 dynamic list.
467
468 * Add support for x86_64 PE+ target.
469
470 * Add support for Score target.
471
472 * ELF: Add --dynamic-list option to specify a list of global symbols
473 whose references shouldn't be bound to the definition within the
474 shared library, or a list of symbols which should be added to the
475 symbol table in the executable.
476
477 * The default output section LMA has changed for allocatable sections from
478 being equal to VMA, to keeping the difference between LMA and VMA the same as
479 the previous output section in the same region. This is a more useful
480 default when using overlays and other cases where you specify an LMA
481 differing from the VMA for some sections.
482
483 * New switch: --print-gc-sections to list any sections removed by garabge
484 collection.
485
486 * ARM: Added --vfp11-denorm-fix option to work around an erratum in current
487 VFP11 coprocessors.
488
489 Changes in 2.17:
490
491 * Support for the Infineon XC16X has been added by KPIT Cummins Infosystems.
492
493 * Modify the Linux linker search order to better match ld.so search order.
494 Look for DT_NEEDED libraries in paths specified by ld.so.conf before
495 searching the default directories, rather than vice versa.
496 Use $prefix/etc/ld.so.conf if it exists, otherwise /etc/ld.so.conf.
497
498 * PE-COFF: Forward exports from DLL's can now be specified in .def files
499 passed directly to ld.
500
501 * Support for the Z80 processor family has been added.
502
503 * Add support for the "@<file>" syntax to the command line, so that extra
504 switches can be read from <file>.
505
506 Changes in 2.16:
507
508 * Support for the R_ARM_V4BX relocation as defined in the ARM AAELF
509 specification has been added via the --fix-v4bx command-line option.
510
511 * New linker script construct AS_NEEDED(), which sets the --as-needed flag
512 for input files listed inside of it.
513
514 * A new command-line option, --sysroot, can be used to override the
515 default sysroot location. It only applies to toolchains that were
516 configured using --with-sysroot.
517
518 * New linker script functions: ORIGIN() and LENGTH() which return information
519 about a specified memory region.
520
521 * Port to MAXQ processor contributed by HCL Tech.
522
523 * Added SEGMENT_START to the linker script language to permit the user to
524 override the base address for a segment from the command-line.
525
526 * ELF: --warn-shared-textrel option to warn if adding a DT_TEXTREL to a shared
527 object.
528
529 * Added SORT_BY_NAME and SORT_BY_ALIGNMENT to the linker script
530 language to permit sorting sections by section name or section
531 maximum alignment.
532
533 * Added a new linker command-line switch, --sort-section name|alignment,
534 to sort sections by section name or maximum alignment.
535
536 * ELF: --add-needed/--no-add-needed options to control if a DT_NEEDED tag
537 should be added when a shared library comes from DT_NEEDED tags.
538
539 * Support for the crx-elf target added.
540
541 * Support for the sh-symbianelf target added.
542
543 * A new linker command-line switch has been added which allows the hash table
544 size to be set to a suitable prime value near to its argument. This switch
545 is --hash-size=<NUMBER>. Also if the switch --reduce-memory-overheads is
546 used, and --hash-size has not been used, then the default value will be set
547 to 1021.
548
549 * Linker map files are now generated with an O(N) algorithm for finding symbols
550 that are defined in each section. This uses about 40% more memory for
551 symbols than the old O(N^2) algorithm. You can use the new
552 --reduce-memory-overheads option to select the old algorithm; this option
553 might also be used in the future to select similar tradeoffs.
554
555 Changes in 2.15:
556
557 * ELF: --as-needed/--no-as-needed options to control if a DT_NEEDED tag should
558 be added only when a shared library is referenced.
559
560 * PE: --large-address-aware option to indicate executables support virtual
561 addresses greater than 2 gigabytes.
562
563 * DWARF 2 support for i386pe added.
564
565 * The linker script operator DEFINED() will now yield 1 only for a symbol that
566 is defined before the statement where DEFINED is used.
567
568 * The MIPS --embedded-relocs (used to embed relocations into binaries for
569 Embedded-PIC code) is deprecated and will be removed in a future release.
570
571 * cr16c support added by NSC.
572
573 * m32r Linux (ELF) support added by Renesas.
574
575 * Improved linker's handling of unresolved symbols. The switch
576 --unresolved-symbols=<method> has been added to tell the linker when it
577 should report them and the switch --warn-unresolved-symbols has been added to
578 make reports be issued as warning messages rather than errors.
579
580 Changes in 2.14:
581
582 * Added support for Xtensa architecture.
583
584 * Added --with-sysroot configure switch to specify a target system root, for
585 linking against a target filesystem image.
586
587 * Added --accept-unknown-linker-format to restore old linker behaviour (pre
588 2.14) of silently accepting and linking in any files in an unknown binary
589 file format.
590
591 * Added --no-omagic to undo the effects of the -N option.
592
593 * Support for Texas Instruments TMS320C4x and TMS320C3x series of
594 DSP's contributed by Michael Hayes and Svein E. Seldal.
595
596 * Added --with-lib-path configure switch to specify default value for
597 LIB_PATH.
598
599 * ARM port to QNX operating system added by Graeme Peterson.
600
601 * IP2K support added by Denis Chertykov.
602
603 Changes in 2.13:
604
605 * Support for the Fujitsu FRV architecture added by Red Hat. Models for FR400
606 and FR500 included.
607
608 Changes in version 2.13:
609
610 * DEC VAX ELF support, by Matt Thomas.
611
612 Changes in version 2.12:
613
614 * Support for Don Knuth's MMIX, by Hans-Peter Nilsson.
615
616 * Support for the OpenRISC 32-bit embedded processor by OpenCores.
617
618 * Support for -z nocopyreloc in the x86 ELF linker, which disables
619 production of copy relocs. Warning: using this option may result in
620 non-sharable applications.
621
622 * Support for -z combreloc in the ELF linker, which puts dynamic
623 relocations against the same symbol together, so that dynamic linker
624 can use an one-entry symbol lookup cache.
625
626 * Support for ELF SHF_MERGE section merging, by Jakub Jelinek.
627
628 Changes in version 2.11:
629
630 * Support for AMD x86-64 architecture, by Jan Hubicka, SuSE Labs.
631
632 * Support added for eliminating duplicate DWARF2 debug information by
633 having the compiler generate the information in sections called
634 .gnu.linkonce.wi.XXXX where XXXX is a checksum for the contents. The
635 linker then merges these sections together into the normal .debug_info
636 section.
637
638 * The native ELF linker now searches the directories in DT_RUNPATH or
639 DT_RPATH of a shared library for shared libraries needed by it.
640
641 * TI C54x support, by Timothy Wall.
642
643 * Added command-line switch --section-start to set the start address of any
644 specified section.
645
646 * Added ability to emit full relocation information in linked executables,
647 enabled by --emit-relocs. Some post-linkage optimization tools need
648 this information in order to be able to correctly identify and perform
649 symbol relative addressing in the event of changes in section contents
650 (instructions being added or deleted, extending data sections, etc.)
651
652 * Support for i860, by Jason Eckhardt (preliminary, alpha quality).
653
654 * Support for CRIS (Axis Communications ETRAX series).
655
656 * Support for PDP-11 and 2.11BSD a.out format, by Lars Brinkhoff.
657
658 Changes in version 2.10:
659
660 * Added AT> to the linker script language to allow load-time allocation of
661 sections into regions.
662
663 * Added garbage collection of unused sections, enabled by --gc-sections.
664 It does require a bit of backend support; currently implemented are
665 arm-elf, avr-elf, d10v-elf, fr30-elf, i386-elf, m32r-elf, m68k-elf,
666 mcore-elf, mips-elf, mn10300-elf, ppc-elf, sh-elf, sparc-elf, and v850-elf.
667 Others will ignore the option.
668
669 * Added SORT to the linker script language to permit sorting sections by file
670 name or section name.
671
672 * Added EXTERN to the linker script language as an equivalent to the -u
673 command-line option.
674
675 * Added ASSERT to the linker script language.
676
677 * Added EXCLUDE_FILE to the linker script language for further control over
678 wildcard file names.
679
680 * Added -O option to optimize linker output (as of this writing, this only
681 affects ELF shared library generation).
682
683 * The -e option now accepts a number as well as a symbol name.
684
685 * Added --no-undefined option to disallow undefined symbols when creating a
686 shared library.
687
688 * The linker now issues a warning, not an error, for an undefined symbol when
689 using -Bsymbolic; use the new --no-undefined option to get the old
690 behaviour.
691
692 * Added --demangle and --no-demangle options.
693
694 Changes in version 2.9:
695
696 * Added SQUAD to the linker script language.
697
698 * New option --no-warn-mismatch.
699
700 * The MEMORY command now parses the attributes to determine where sections that
701 are not placed in a specific memory region are placed.
702
703 Changes in version 2.8:
704
705 * Linker scripts may now contain shell wildcard characters for file and section
706 names.
707
708 * The linker now supports symbol versions in ELF.
709
710 * The NOCROSSREFS command was added to the linker script language.
711
712 * The LOADADDR expression was added to the linker script language.
713
714 * MAX and MIN functions were added to the linker script language.
715
716 * The OVERLAY construct was added to the linker script language.
717
718 * New option --warn-section-align to warn when the address of an output section
719 changes due to alignment of an input section.
720
721 * New options --filter/-F and --auxiliary/-f.
722
723 Changes in version 2.7:
724
725 * New option --cref to print out a cross reference table.
726
727 * New option --wrap SYMBOL.
728
729 * New option --no-whole-archive, to turn off the effect of --whole-archive.
730
731 * Input sections assigned to the output section /DISCARD/ in the linker script
732 are not included in the output file.
733
734 * The SunOS and ELF linkers now merge stabs debugging information which uses
735 the N_BINCL and N_EINCL stab types. This reduces the amount of debugging
736 information generated.
737
738 Changes in version 2.6:
739
740 * When an ELF section name is representable as a C identifier (this is not true
741 of most ELF section names), the linker will automatically define symbols
742 __start_SECNAME and __stop_SECNAME, where SECNAME is the section name, at the
743 beginning and the end of the section. This is used by glibc.
744
745 Addendum: Current versions of the linker (at least for version 2.18 onwards
746 and possibly much earlier as well) place two restrictions on this feature: The
747 symbols are only implemented for orphaned sections, not for explicitly placed
748 sections and they are PROVIDEd rather than being defined.
749
750 * When an ELF section named .gnu.warning is encountered in an input file, the
751 contents of the section are displayed as an error message, and the section is
752 not copied into the output file. This is used by glibc.
753
754 * When an ELF section named .gnu.warning.SYMBOL is encountered in an input
755 file, and the symbol SYMBOL is referenced by some object file, the contents of
756 the section are displayed as an error message. The section is not copied into
757 the output file, unless doing a relocatable or shared link. This is used by
758 glibc.
759
760 * New options -split-by-reloc and -split-by-file.
761
762 * The linker now supports linking PIC compiled code on SPARC SunOS. It can
763 also create SPARC SunOS shared libraries, and, like the native SunOS linker,
764 will do so whenever there is an undefined symbol in the link and neither the -e
765 nor the -r option was used.
766
767 * The -rpath option may be used on SunOS to set the list of directories to be
768 searched at run time. This overrides the default of building the list from the
769 -L options.
770
771 * The COFF linker now combines debugging information for structs, unions, and
772 enums, so that even if the same type is defined in multiple input files it will
773 only be defined once in the output file. The --traditional-format switch will
774 prevent this optimization.
775
776 Changes in version 2.5:
777
778 * The linker now supports linking against SunOS shared libraries. It still can
779 not link SunOS PIC (Position Independent Code) files, so it can not be used to
780 generate shared libraries.
781
782 * The linker now supports linking against ELF shared libraries for the i386
783 (UnixWare) and SPARC (Solaris). It can also link ELF PIC files, and can be
784 used to generate shared libraries. Shared library generation is not well
785 tested; please report any problems encountered. The linker is now enabled for
786 Solaris again.
787
788 * Eric Youngdale has contributed Linux support code, including linking against
789 Linux a.out shared libraries. The linker produces Linux QMAGIC binaries.
790
791 * The ELF backend has been converted to the new linker code. To use the new
792 ELF linker, each particular target requires a relocation function. So far,
793 this function has been written for i386 (UnixWare), SPARC (Solaris) MIPS (Irix
794 5), and HPPA ELF targets.
795
796 * The -( (--start-group) and -) (--end-group) options have been added to
797 support searching a group of archives as though they were a single archive.
798 This can also be used in a linker script, as GROUP ( files ).
799
800 * When a file is named on the command line, and the linker does not recognize
801 it as an object file, the linker will now treat the file as a linker script
802 file. A linker script named in this way augments, but does not replace, the
803 default linker script.
804
805 * The -warn-once option was added. It causes the linker to only warn once per
806 undefined symbol, rather than once per reference.
807
808 * The COFF backend has been converted to the new linker code. As with ELF, to
809 use the new linker, each particular target requires a relocation function. So
810 far, this function has been written for the i386, m68k, a29k and SH targets.
811
812 * The -V flag was made a synonym for -v, for SVR4 compatibility. The old -V
813 behaviour is available via --verbose.
814
815 Changes in version 2.4:
816
817 * New linker code, by Steve Chamberlain and Ian Taylor. For a.out and ecoff
818 formats (so far), this should result in considerable savings in time
819 and memory used while linking; slightly poorer performance than
820 before for formats not converted yet.
821
822 * Command-line parsing is no longer done with flex. This means
823 oddball characters in filenames won't get treated as argument
824 separators.
825
826 * HP-PA ELF support, by Jeff Law. (No SOM support yet.)
827
828 * Mach i386 support, by David Mackenzie.
829
830 * Irix 4 shared libraries are now supported (Irix 5 uses ELF, and ELF shared
831 libraries are not yet supported).
832
833 * COFF shared libraries (as on SCO) should work as well.
834
835 * The linker is disabled for Solaris. (Actually, it was in 2.3 also, I just
836 forgot to note it.) Some of their C library routines don't work when
837 statically linked, and the GNU linker doesn't support dynamic linking yet.
838
839 Changes in version 2.3:
840
841 * Weak symbols are now supported.
842
843 * ELF support has been added. The linker has been bootstrapped on
844 UnixWare and Solaris.
845
846 * Alpha OSF/1 support has been added (non dynamic linking only).
847
848 Changes in version 2.2:
849
850 * The `bfd' library has been updated to reduce a.out-format string
851 table size. The effect of this is that files linked from many input
852 files with duplicate symbols (`-g' debugging records, or identical
853 static symbols) should be much smaller.
854
855 Changes in version 2.1:
856
857 * The ld -ySYMBOL flag (to trace references to SYMBOL) is now implemented.
858
859 * There is now support for writing ECOFF files, so ld and the
860 other utilities should work on Risc/Ultrix and Irix.
861
862 \f
863 Copyright (C) 2012-2021 Free Software Foundation, Inc.
864
865 Copying and distribution of this file, with or without modification,
866 are permitted in any medium without royalty provided the copyright
867 notice and this notice are preserved.
868
869 Local variables:
870 fill-column: 79
871 End: