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ld: Support customized output section type
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1 -*- text -*-
2
3 * TYPE=<type> is now supported in an output section description to set the
4 section type value.
5
6 Changes in 2.38:
7
8 * Add -z pack-relative-relocs/-z no pack-relative-relocs to x86 ELF
9 linker to pack relative relocations in the DT_RELR section.
10
11 * Add support for the LoongArch architecture.
12
13 * Add -z indirect-extern-access/-z noindirect-extern-access to x86 ELF
14 linker to control canonical function pointers and copy relocation.
15
16 * Add --max-cache-size=SIZE to set the the maximum cache size to SIZE
17 bytes.
18
19 Changes in 2.37:
20
21 * arm-symbianelf support removed.
22
23 * Add -z report-relative-reloc to x86 ELF linker to report dynamic
24 relative relocations.
25
26 * Add -z start-stop-gc to disable special treatment of __start_*/__stop_*
27 references when --gc-sections.
28
29 * Add -Bno-symbolic to cancel -Bsymbolic and -Bsymbolic-functions.
30
31 Changes in 2.36:
32
33 * Add libdep plugin, for linking dependencies of static libraries that
34 were recorded by ar in the __.LIBDEP archive member.
35
36 * Add --error-handling-script=<NAME> command line option to allow a helper
37 script to be invoked when an undefined symbol or a missing library is
38 encountered. This option can be suppressed via the configure time
39 switch: --enable-error-handling-script=no.
40
41 * Add -z lam-u48 to x86-64 ELF linker to generate LAM_U48 property.
42
43 * Add -z lam-u57 to x86-64 ELF linker to enerate LAM_U57 property.
44
45 * Add -z lam-u48-report=[none|warning|error] to report missing LAM_U48
46 property.
47
48 * Add -z lam-u57-report=[none|warning|error] to report missing LAM_U57
49 property.
50
51 * Add -z lam-report=[none|warning|error] to report missing LAM_U48 and
52 LAM_U57 properties.
53
54 * Add -z x86-64-{baseline|v[234]} to the x86 ELF linker to mark
55 x86-64-{baseline|v[234]} ISA level as needed.
56
57 * Add -z unique-symbol to avoid duplicated local symbol names.
58
59 * The creation of PE format DLLs now defaults to using a more secure set of DLL
60 characteristics.
61
62 * The linker now deduplicates the types in .ctf sections. The new
63 command-line option --ctf-share-types describes how to do this:
64 its default value, share-unconflicted, produces the most compact
65 output.
66
67 * The linker now omits the "variable section" from .ctf sections by
68 default, saving space. This is almost certainly what you want
69 unless you are working on a project that has its own analogue
70 of symbol tables that are not reflected in the ELF symtabs.
71
72 * Add support for the SHF_GNU_RETAIN ELF section flag.
73 This flag specifies that the section should not be garbage collected by the
74 linker.
75
76 Changes in 2.35:
77
78 * X86 NaCl target support is removed.
79
80 * Add ELF linker command-line options, --export-dynamic-symbol and
81 --export-dynamic-symbol-list, to make symbols dynamic.
82
83 * Add a configure option, --enable-textrel-check=[no|yes|warning|error],
84 to decide what ELF linker should do by default with DT_TEXTREL in an
85 executable or shared library. Default to yes for Linux/x86 targets.
86
87 * The -Map=<filename> command line option has been extended so that if
88 <filename> is a directory then <filename>/<output-filename>.map will be
89 created.
90
91 * Add a command-line option for ELF linker, --warn-textrel, to warn that
92 DT_TEXTREL is set in a position-independent executable or shared object.
93
94 * Add command-line options --enable-non-contiguous-regions and
95 --enable-non-contiguous-regions-warnings.
96
97 * Add command-line option --imagic for the pdp11-aout target to output format
98 IMAGIC (0411) for separate instruction and data spaces, and change the
99 default format option for pdp11-aout to be --omagic.
100
101 * Relative pathnames in INPUT() and GROUP() directives in linker scripts are
102 searched relative to the directory of the linker script before other search
103 paths.
104
105 * Add ELF linker command-line option `-z start-stop-visibility=...' to control
106 the visibility of synthetic `__start_SECNAME` and `__stop_SECNAME` symbols.
107
108 * Add command-line option --dependency-file to write a Make-style dependency
109 file listing the input files consulted by the linker, like the files written
110 by the compiler's -M -MP options.
111
112 Changes in 2.34:
113
114 * The ld check for "PHDR segment not covered by LOAD segment" is more
115 effective, catching cases that were wrongly allowed by previous versions of
116 ld. If you see this error it is likely you are linking with a bad linker
117 script or the binary you are building is not intended to be loaded by a
118 dynamic loader. In the latter case --no-dynamic-linker is appropriate.
119
120 * cr16c support removed.
121
122 * Add support for z80-elf.
123
124 * Add support for relocation of each byte or word of multibyte value to Z80
125 targets.
126
127 * Add support for Zilog eZ80 (both ADL and Z80 mode) and Zilog Z180 CPUs.
128
129 Changes in 2.33:
130
131 * Add command-line option --no-print-map-discarded.
132
133 * The Cortex-A53 Erratum 843419 workaround now supports a choice of which
134 workaround to use. The option --fix-cortex-a53-843419 now takes an
135 optional argument --fix-cortex-a53-843419[=full|adr|adrp] which can be
136 used to force a particular workaround to be used. See --help for AArch64
137 for more details.
138
139 * Add target handlers for AArch64 for ELF GNU program properties.
140
141 * Add support for GNU_PROPERTY_AARCH64_FEATURE_1_BTI in ELF GNU program
142 properties in the AArch64 ELF linker.
143
144 * Add support for GNU_PROPERTY_AARCH64_FEATURE_1_PAC in ELF GNU program
145 properties in the AArch64 ELF linker.
146
147 * Add -z force-bti for AArch64 to enable GNU_PROPERTY_AARCH64_FEATURE_1_BTI
148 on output while warning about missing GNU_PROPERTY_AARCH64_FEATURE_1_BTI
149 on inputs and use PLTs protected with BTI.
150
151 * Add -z pac-plt for AArch64 to pick PAC enabled PLTs.
152
153 Changes in 2.32:
154
155 * Report property change in linker map file when merging GNU properties.
156
157 * Add support for the C-SKY processor series.
158
159 * -t now doesn't report members within archives, unless -t is given twice.
160 A single -t is now more useful when generating a list of files that should be
161 packaged for a linker bug report. For example:
162 gcc hello.c -save-temps -Wl,-t | xargs realpath | sort | uniq > files
163 tar cJf test.tar.xz `cat files`
164
165 Changes in 2.31:
166
167 * Speed up direct linking with DLLs for Cygwin and Mingw targets.
168
169 * Add a configure option --enable-separate-code to decide whether
170 -z separate-code should be enabled in ELF linker by default. Default
171 to yes for Linux/x86 targets. Note that -z separate-code can increase
172 disk and memory size.
173
174 Changes in 2.30:
175
176 * Add -z separate-code to generate separate code PT_LOAD segment.
177
178 * Add "-z undefs" command-line option as the inverse of the "-z defs" option.
179
180 * Add -z globalaudit command-line option to force audit libraries to be run
181 for every dynamic object loaded by an executable - provided that the loader
182 supports this functionality.
183
184 * Tighten linker script grammar around file name specifiers to prevent the use
185 of SORT_BY_ALIGNMENT and SORT_BY_INIT_PRIORITY on filenames. These would
186 previously be accepted but had no effect.
187
188 * The EXCLUDE_FILE directive can now be placed within any SORT_* directive
189 within input section lists.
190
191 Changes in 2.29:
192
193 * Support for -z shstk in the x86 ELF linker to generate
194 GNU_PROPERTY_X86_FEATURE_1_SHSTK in ELF GNU program properties.
195
196 * Add support for GNU_PROPERTY_X86_FEATURE_1_SHSTK in ELF GNU program
197 properties in the x86 ELF linker.
198
199 * Add support for GNU_PROPERTY_X86_FEATURE_1_IBT in ELF GNU program
200 properties in the x86 ELF linker.
201
202 * Support for -z ibtplt in the x86 ELF linker to generate IBT-enabled
203 PLT.
204
205 * Support for -z ibt in the x86 ELF linker to generate IBT-enabled
206 PLT as well as GNU_PROPERTY_X86_FEATURE_1_IBT in ELF GNU program
207 properties.
208
209 * Add support for ELF SHF_GNU_MBIND and PT_GNU_MBIND_XXX.
210
211 * Add support for ELF GNU program properties.
212
213 * Add support for the Texas Instruments PRU processor.
214
215 * When configuring for arc*-*-linux* targets the default linker emulation will
216 change if --with-cpu=nps400 is used at configure time.
217
218 * Improve assignment of LMAs to orphan sections in some edge cases where a
219 mixture of both AT>LMA_REGION and AT(LMA) are used.
220
221 * Orphan sections placed after an empty section that has an AT(LMA) will now
222 take an load memory address starting from LMA.
223
224 * Section groups can now be resolved (the group deleted and the group members
225 placed like normal sections) at partial link time either using the new linker
226 option --force-group-allocation or by placing FORCE_GROUP_ALLOCATION into the
227 linker script.
228
229 Changes in 2.28:
230
231 * The EXCLUDE_FILE linker script construct can now be applied outside of the
232 section list in order for the exclusions to apply over all input sections in
233 the list.
234
235 * Add support for the RISC-V architecture.
236
237 * The command-line option --no-eh-frame-hdr can now be used in ELF based
238 linkers to disable the automatic generation of .eh_frame_hdr sections.
239
240 * Add --in-implib=<infile> to the ARM linker to enable specifying a set of
241 Secure Gateway veneers that must exist in the output import library specified
242 by --out-implib=<outfile> and the address they must have. As such,
243 --in-implib is only supported in combination with --cmse-implib.
244
245 * Extended the --out-implib=<file> option, previously restricted to x86 PE
246 targets, to any ELF based target. This allows the generation of an import
247 library for an ELF executable, which can then be used by another application
248 to link against the executable.
249
250 Changes in 2.27:
251
252 * Add a configure option --enable-relro to decide whether -z relro should
253 be enabled in ELF linker by default. Default to yes for all Linux
254 targets except FRV, HPPA, IA64 and MIPS. Note that -z relro can increase
255 disk and memory size.
256
257 * Support for -z noreloc-overflow in the x86-64 ELF linker to disable
258 relocation overflow check.
259
260 * Add -z common/-z nocommon options for ELF targets to control whether to
261 convert common symbols to the STT_COMMON type during a relocatable link.
262
263 * Support for -z nodynamic-undefined-weak in the x86 ELF linker, which
264 avoids dynamic relocations against undefined weak symbols in executable.
265
266 * The NOCROSSREFSTO command was added to the linker script language.
267
268 * Add --no-apply-dynamic-relocs to the AArch64 linker to do not apply link-time
269 values for dynamic relocations.
270
271 Changes in 2.26:
272
273 * Add --fix-stm32l4xx-629360 to the ARM linker to enable a link-time
274 workaround for a bug in the bus matrix / memory controller for some of
275 the STM32 Cortex-M4 based products (STM32L4xx)
276
277 * Add a configure option --enable-compressed-debug-sections={all,ld} to
278 decide whether DWARF debug sections should be compressed by default.
279
280 * Add support for the ARC EM/HS, and ARC600/700 architectures.
281
282 * Experimental support for linker garbage collection (--gc-sections)
283 has been enabled for COFF and PE based targets.
284
285 * New command-line option for ELF targets to compress DWARF debug
286 sections, --compress-debug-sections=[none|zlib|zlib-gnu|zlib-gabi].
287
288 * New command-line option, --orphan-handling=[place|warn|error|discard], to
289 adjust how orphan sections are handled. The default is 'place' which gives
290 the current behaviour, 'warn' and 'error' issue a warning or error
291 respectively when orphan sections are found, and 'discard' will discard all
292 orphan sections.
293
294 * Add support for LLVM plugin.
295
296 * Add --print-memory-usage option to report memory blocks usage.
297
298 * Add --require-defined option, it's like --undefined except the new symbol
299 must be defined by the end of the link.
300
301 Changes in 2.25:
302
303 * PE binaries now once again contain real timestamps by default. To disable
304 the inclusion of a timestamp in a PE binary, use the --no-insert-timestamp
305 command-line option.
306
307 * Replace support for openrisc and or32 with support for or1k.
308
309 * Add support for the --build-id command-line option to COFF based targets.
310
311 * x86/x86_64 pe-coff now supports the --build-id option.
312
313 * Add support for the Andes NDS32.
314
315 Changes in 2.24:
316
317 * Add LOG2CEIL() builtin function to the linker script language
318
319 * Add support for the Texas Instruments MSP430X processor.
320
321 * Add support for Altera Nios II.
322
323 * Add support for the V850E3V5 architecture.
324
325 * Add support for the Imagination Technologies Meta processor.
326
327 * --enable-new-dtags no longer generates old dtags in addition to new dtags.
328
329 * Remove linker support for MIPS ECOFF targets.
330
331 * Add ALIGN_WITH_INPUT to the linker script language to force the alignment of
332 an output section to use the maximum alignment of all its input sections.
333
334 Changes in 2.23:
335
336 * Enable compressed debug section feature for x86/x86_64 pe-coff.
337
338 * Add support for the 64-bit ARM architecture: AArch64.
339
340 * Added SORT_NONE to the linker script language to disable section sorting.
341
342 * Add a linker-provided symbol when producing ELF output, '__ehdr_start'
343 to point to the ELF file header (and nearby program headers) in the
344 program's memory image.
345
346 * Add support for S12X processor.
347
348 * Add support for the VLE extension to the PowerPC architecture.
349
350 * Add support for the Freescale XGATE architecture.
351
352 * Add option -f FILE on AIX (for response file).
353
354 * Add support for the Renesas RL78 architecture.
355
356 * Add support for the Adapteva EPIPHANY architecture.
357
358 Changes in 2.22:
359
360 * --copy-dt-needed-entries is no longer enabled by default. Instead
361 --no-copy-dt-needed-entries is the default.
362
363 * INPUT_SECTION_FLAGS has been added to the linker script language
364 to allow selection of input sections by section header section flags.
365
366 * Add support for the Tilera TILEPro and TILE-Gx architectures.
367
368 * Added SORT_BY_INIT_PRIORITY to the linker script language to permit
369 sorting sections by numerical value of the GCC init_priority attribute
370 encoded in the section name.
371
372 Changes in 2.21:
373
374 * Linker script expression evaluation is somewhat more sane. This may
375 break scripts that depend on quirks of the old expression evaluation.
376
377 * Turn off underscoring for x86_64 PE+-COFF targets. For old behavior the
378 option --enable-leading-mingw64-underscores can be used on configure of
379 bfd.
380
381 * Add support for the TMS320C6000 (TI C6X) processor family.
382
383 * --add-needed renamed to --copy-dt-needed-entries in order to avoid confusion
384 with --as-needed option.
385
386 * Extend .def file syntax by '== <ID>' for imports and exports. This allows
387 to alias the import/export table name written in PE image.
388
389 * Add --exclude-all-symbols option to PE based linkers. This prevents all
390 symbols from automatically being exported.
391
392 * Add support for the Renesas RX processor.
393
394 * Add support for alpha-vms target.
395
396 Changes in 2.20:
397
398 * GNU/Linux targets now support the STB_GNU_UNIQUE symbol binding. This is a
399 GNU extension to the standard set of ELF symbol bindings. The binding will
400 be passed on to the dynamic linker which will make sure that in the entire
401 process there is just one symbol with the given name and type in use.
402
403 * PE targets now support a GNU extension to allow the alignment of common
404 common symbols to be specified. This support uses custom options in
405 the .drectve section, which will be disregarded by the native tools.
406
407 * PE targets now add primitive support for ELF version scripts; symbols
408 are not versioned, but the local and global symbol visibility directives
409 are respected when filtering symbols in auto-export mode.
410
411 * New option --no-export-dynamic to undo the effect of the -E and
412 --export-dynamic options.
413
414 * ELF: --warn-alternate-em option to warn if an object has alternate
415 ELF machine code.
416
417 * New script function REGION_ALIAS to add alias names to memory regions.
418
419 * PE targets no longer make use of the long section names PE extension to
420 the COFF format when generating executable images, by default. The old
421 (slightly non-conformant) behaviour can still be invoked by using the
422 new '--enable-long-section-names' command-line option. It is also enabled
423 automatically in the presence of un-stripped debug information, as GDB
424 needs to be able to find the debug info sections by their full names.
425
426 * For GNU/Linux systems the linker will now avoid processing any relocations
427 made against symbols of the STT_GNU_IFUNC type and instead emit them into
428 the resulting binary for processing by the loader.
429
430 * --as-needed now links in a dynamic library if it satisfies undefined
431 symbols in regular objects, or in other dynamic libraries. In the
432 latter case the library is not linked if it is found in a DT_NEEDED
433 entry of one of the libraries already linked.
434
435 * Add a new command-line option, -Ttext-segment ADDR, for ELF targets
436 to set the address of the first byte of the text segment.
437
438 * Add support for Sunplus score architecture.
439
440 * Add new option --use-nul-prefixed-import-tables to ld for PE targets to
441 allow fallback to old import table generation with null element prefix.
442
443 * Windows PE systems now support a new --exclude-modules-for-implib option,
444 allowing users to partition object files and archive members between a DLL
445 and its associated import library as they are generated during linking.
446
447 * Add support for Lattice Mico32 (lm32) architecture.
448
449 * Add CR16 ELF --embedded-relocs (used to embedded relocations into binaries
450 for Embedded-PIC code) option.
451
452 * Add to the PE/PE+ targets the support of two different kinds of
453 pseudo-relocations. They can be selected by the switches
454 --enable-runtime-pseudo-reloc-v1 and --enable-runtime-pseudo-reloc-v2.
455 For the switch --enable-runtime-pseudo-reloc it uses for 32-bit
456 runtime pseudo relocation version one, for 64-bit the version two.
457
458 Changes in 2.19:
459
460 * Linker scripts support a new INSERT command that makes it easier to
461 augment the default script.
462
463 * Linker script input section filespecs may now specify a file within an
464 archive by writing "archive:file".
465
466 * The --sort-common switch now has an optional argument which specifies the
467 direction of sorting.
468
469 * The M68K linker now supports multiple GOT generation schemes controlled via
470 the --got=<type> command-line option.
471
472 * The ARM EABI linker will now generate stubs for function calls to symbols
473 that are too far away. The placement of the stubs is controlled by a new
474 linker command-line option: --stub-group-size=N.
475
476 Changes in 2.18:
477
478 * Linker sources now released under version 3 of the GNU General Public
479 License.
480
481 * ELF: New --build-id option to generate a unique per-binary identifier
482 embedded in a note section.
483
484 * Added support for National Semicondutor CompactRISC (ie CR16) target.
485
486 * -l:foo now searches the library path for a filename called foo,
487 without converting it to libfoo.a or libfoo.so.
488
489 * Add a new command-line option '--default-script=FILE' or '-dT FILE'
490 which specifies a replacement for the built in, default linker
491 script.
492
493 * ELF: Add -Bsymbolic-functions, --dynamic-list-cpp-new, which puts C++
494 operator new and delete on the dynamic list, and --dynamic-list-data,
495 builtin list for --dynamic-list, which puts global data symbols on the
496 dynamic list.
497
498 * Add support for x86_64 PE+ target.
499
500 * Add support for Score target.
501
502 * ELF: Add --dynamic-list option to specify a list of global symbols
503 whose references shouldn't be bound to the definition within the
504 shared library, or a list of symbols which should be added to the
505 symbol table in the executable.
506
507 * The default output section LMA has changed for allocatable sections from
508 being equal to VMA, to keeping the difference between LMA and VMA the same as
509 the previous output section in the same region. This is a more useful
510 default when using overlays and other cases where you specify an LMA
511 differing from the VMA for some sections.
512
513 * New switch: --print-gc-sections to list any sections removed by garabge
514 collection.
515
516 * ARM: Added --vfp11-denorm-fix option to work around an erratum in current
517 VFP11 coprocessors.
518
519 Changes in 2.17:
520
521 * Support for the Infineon XC16X has been added by KPIT Cummins Infosystems.
522
523 * Modify the Linux linker search order to better match ld.so search order.
524 Look for DT_NEEDED libraries in paths specified by ld.so.conf before
525 searching the default directories, rather than vice versa.
526 Use $prefix/etc/ld.so.conf if it exists, otherwise /etc/ld.so.conf.
527
528 * PE-COFF: Forward exports from DLL's can now be specified in .def files
529 passed directly to ld.
530
531 * Support for the Z80 processor family has been added.
532
533 * Add support for the "@<file>" syntax to the command line, so that extra
534 switches can be read from <file>.
535
536 Changes in 2.16:
537
538 * Support for the R_ARM_V4BX relocation as defined in the ARM AAELF
539 specification has been added via the --fix-v4bx command-line option.
540
541 * New linker script construct AS_NEEDED(), which sets the --as-needed flag
542 for input files listed inside of it.
543
544 * A new command-line option, --sysroot, can be used to override the
545 default sysroot location. It only applies to toolchains that were
546 configured using --with-sysroot.
547
548 * New linker script functions: ORIGIN() and LENGTH() which return information
549 about a specified memory region.
550
551 * Port to MAXQ processor contributed by HCL Tech.
552
553 * Added SEGMENT_START to the linker script language to permit the user to
554 override the base address for a segment from the command-line.
555
556 * ELF: --warn-shared-textrel option to warn if adding a DT_TEXTREL to a shared
557 object.
558
559 * Added SORT_BY_NAME and SORT_BY_ALIGNMENT to the linker script
560 language to permit sorting sections by section name or section
561 maximum alignment.
562
563 * Added a new linker command-line switch, --sort-section name|alignment,
564 to sort sections by section name or maximum alignment.
565
566 * ELF: --add-needed/--no-add-needed options to control if a DT_NEEDED tag
567 should be added when a shared library comes from DT_NEEDED tags.
568
569 * Support for the crx-elf target added.
570
571 * Support for the sh-symbianelf target added.
572
573 * A new linker command-line switch has been added which allows the hash table
574 size to be set to a suitable prime value near to its argument. This switch
575 is --hash-size=<NUMBER>. Also if the switch --reduce-memory-overheads is
576 used, and --hash-size has not been used, then the default value will be set
577 to 1021.
578
579 * Linker map files are now generated with an O(N) algorithm for finding symbols
580 that are defined in each section. This uses about 40% more memory for
581 symbols than the old O(N^2) algorithm. You can use the new
582 --reduce-memory-overheads option to select the old algorithm; this option
583 might also be used in the future to select similar tradeoffs.
584
585 Changes in 2.15:
586
587 * ELF: --as-needed/--no-as-needed options to control if a DT_NEEDED tag should
588 be added only when a shared library is referenced.
589
590 * PE: --large-address-aware option to indicate executables support virtual
591 addresses greater than 2 gigabytes.
592
593 * DWARF 2 support for i386pe added.
594
595 * The linker script operator DEFINED() will now yield 1 only for a symbol that
596 is defined before the statement where DEFINED is used.
597
598 * The MIPS --embedded-relocs (used to embed relocations into binaries for
599 Embedded-PIC code) is deprecated and will be removed in a future release.
600
601 * cr16c support added by NSC.
602
603 * m32r Linux (ELF) support added by Renesas.
604
605 * Improved linker's handling of unresolved symbols. The switch
606 --unresolved-symbols=<method> has been added to tell the linker when it
607 should report them and the switch --warn-unresolved-symbols has been added to
608 make reports be issued as warning messages rather than errors.
609
610 Changes in 2.14:
611
612 * Added support for Xtensa architecture.
613
614 * Added --with-sysroot configure switch to specify a target system root, for
615 linking against a target filesystem image.
616
617 * Added --accept-unknown-linker-format to restore old linker behaviour (pre
618 2.14) of silently accepting and linking in any files in an unknown binary
619 file format.
620
621 * Added --no-omagic to undo the effects of the -N option.
622
623 * Support for Texas Instruments TMS320C4x and TMS320C3x series of
624 DSP's contributed by Michael Hayes and Svein E. Seldal.
625
626 * Added --with-lib-path configure switch to specify default value for
627 LIB_PATH.
628
629 * ARM port to QNX operating system added by Graeme Peterson.
630
631 * IP2K support added by Denis Chertykov.
632
633 Changes in 2.13:
634
635 * Support for the Fujitsu FRV architecture added by Red Hat. Models for FR400
636 and FR500 included.
637
638 Changes in version 2.13:
639
640 * DEC VAX ELF support, by Matt Thomas.
641
642 Changes in version 2.12:
643
644 * Support for Don Knuth's MMIX, by Hans-Peter Nilsson.
645
646 * Support for the OpenRISC 32-bit embedded processor by OpenCores.
647
648 * Support for -z nocopyreloc in the x86 ELF linker, which disables
649 production of copy relocs. Warning: using this option may result in
650 non-sharable applications.
651
652 * Support for -z combreloc in the ELF linker, which puts dynamic
653 relocations against the same symbol together, so that dynamic linker
654 can use an one-entry symbol lookup cache.
655
656 * Support for ELF SHF_MERGE section merging, by Jakub Jelinek.
657
658 Changes in version 2.11:
659
660 * Support for AMD x86-64 architecture, by Jan Hubicka, SuSE Labs.
661
662 * Support added for eliminating duplicate DWARF2 debug information by
663 having the compiler generate the information in sections called
664 .gnu.linkonce.wi.XXXX where XXXX is a checksum for the contents. The
665 linker then merges these sections together into the normal .debug_info
666 section.
667
668 * The native ELF linker now searches the directories in DT_RUNPATH or
669 DT_RPATH of a shared library for shared libraries needed by it.
670
671 * TI C54x support, by Timothy Wall.
672
673 * Added command-line switch --section-start to set the start address of any
674 specified section.
675
676 * Added ability to emit full relocation information in linked executables,
677 enabled by --emit-relocs. Some post-linkage optimization tools need
678 this information in order to be able to correctly identify and perform
679 symbol relative addressing in the event of changes in section contents
680 (instructions being added or deleted, extending data sections, etc.)
681
682 * Support for i860, by Jason Eckhardt (preliminary, alpha quality).
683
684 * Support for CRIS (Axis Communications ETRAX series).
685
686 * Support for PDP-11 and 2.11BSD a.out format, by Lars Brinkhoff.
687
688 Changes in version 2.10:
689
690 * Added AT> to the linker script language to allow load-time allocation of
691 sections into regions.
692
693 * Added garbage collection of unused sections, enabled by --gc-sections.
694 It does require a bit of backend support; currently implemented are
695 arm-elf, avr-elf, d10v-elf, fr30-elf, i386-elf, m32r-elf, m68k-elf,
696 mcore-elf, mips-elf, mn10300-elf, ppc-elf, sh-elf, sparc-elf, and v850-elf.
697 Others will ignore the option.
698
699 * Added SORT to the linker script language to permit sorting sections by file
700 name or section name.
701
702 * Added EXTERN to the linker script language as an equivalent to the -u
703 command-line option.
704
705 * Added ASSERT to the linker script language.
706
707 * Added EXCLUDE_FILE to the linker script language for further control over
708 wildcard file names.
709
710 * Added -O option to optimize linker output (as of this writing, this only
711 affects ELF shared library generation).
712
713 * The -e option now accepts a number as well as a symbol name.
714
715 * Added --no-undefined option to disallow undefined symbols when creating a
716 shared library.
717
718 * The linker now issues a warning, not an error, for an undefined symbol when
719 using -Bsymbolic; use the new --no-undefined option to get the old
720 behaviour.
721
722 * Added --demangle and --no-demangle options.
723
724 Changes in version 2.9:
725
726 * Added SQUAD to the linker script language.
727
728 * New option --no-warn-mismatch.
729
730 * The MEMORY command now parses the attributes to determine where sections that
731 are not placed in a specific memory region are placed.
732
733 Changes in version 2.8:
734
735 * Linker scripts may now contain shell wildcard characters for file and section
736 names.
737
738 * The linker now supports symbol versions in ELF.
739
740 * The NOCROSSREFS command was added to the linker script language.
741
742 * The LOADADDR expression was added to the linker script language.
743
744 * MAX and MIN functions were added to the linker script language.
745
746 * The OVERLAY construct was added to the linker script language.
747
748 * New option --warn-section-align to warn when the address of an output section
749 changes due to alignment of an input section.
750
751 * New options --filter/-F and --auxiliary/-f.
752
753 Changes in version 2.7:
754
755 * New option --cref to print out a cross reference table.
756
757 * New option --wrap SYMBOL.
758
759 * New option --no-whole-archive, to turn off the effect of --whole-archive.
760
761 * Input sections assigned to the output section /DISCARD/ in the linker script
762 are not included in the output file.
763
764 * The SunOS and ELF linkers now merge stabs debugging information which uses
765 the N_BINCL and N_EINCL stab types. This reduces the amount of debugging
766 information generated.
767
768 Changes in version 2.6:
769
770 * When an ELF section name is representable as a C identifier (this is not true
771 of most ELF section names), the linker will automatically define symbols
772 __start_SECNAME and __stop_SECNAME, where SECNAME is the section name, at the
773 beginning and the end of the section. This is used by glibc.
774
775 Addendum: Current versions of the linker (at least for version 2.18 onwards
776 and possibly much earlier as well) place two restrictions on this feature: The
777 symbols are only implemented for orphaned sections, not for explicitly placed
778 sections and they are PROVIDEd rather than being defined.
779
780 * When an ELF section named .gnu.warning is encountered in an input file, the
781 contents of the section are displayed as an error message, and the section is
782 not copied into the output file. This is used by glibc.
783
784 * When an ELF section named .gnu.warning.SYMBOL is encountered in an input
785 file, and the symbol SYMBOL is referenced by some object file, the contents of
786 the section are displayed as an error message. The section is not copied into
787 the output file, unless doing a relocatable or shared link. This is used by
788 glibc.
789
790 * New options -split-by-reloc and -split-by-file.
791
792 * The linker now supports linking PIC compiled code on SPARC SunOS. It can
793 also create SPARC SunOS shared libraries, and, like the native SunOS linker,
794 will do so whenever there is an undefined symbol in the link and neither the -e
795 nor the -r option was used.
796
797 * The -rpath option may be used on SunOS to set the list of directories to be
798 searched at run time. This overrides the default of building the list from the
799 -L options.
800
801 * The COFF linker now combines debugging information for structs, unions, and
802 enums, so that even if the same type is defined in multiple input files it will
803 only be defined once in the output file. The --traditional-format switch will
804 prevent this optimization.
805
806 Changes in version 2.5:
807
808 * The linker now supports linking against SunOS shared libraries. It still can
809 not link SunOS PIC (Position Independent Code) files, so it can not be used to
810 generate shared libraries.
811
812 * The linker now supports linking against ELF shared libraries for the i386
813 (UnixWare) and SPARC (Solaris). It can also link ELF PIC files, and can be
814 used to generate shared libraries. Shared library generation is not well
815 tested; please report any problems encountered. The linker is now enabled for
816 Solaris again.
817
818 * Eric Youngdale has contributed Linux support code, including linking against
819 Linux a.out shared libraries. The linker produces Linux QMAGIC binaries.
820
821 * The ELF backend has been converted to the new linker code. To use the new
822 ELF linker, each particular target requires a relocation function. So far,
823 this function has been written for i386 (UnixWare), SPARC (Solaris) MIPS (Irix
824 5), and HPPA ELF targets.
825
826 * The -( (--start-group) and -) (--end-group) options have been added to
827 support searching a group of archives as though they were a single archive.
828 This can also be used in a linker script, as GROUP ( files ).
829
830 * When a file is named on the command line, and the linker does not recognize
831 it as an object file, the linker will now treat the file as a linker script
832 file. A linker script named in this way augments, but does not replace, the
833 default linker script.
834
835 * The -warn-once option was added. It causes the linker to only warn once per
836 undefined symbol, rather than once per reference.
837
838 * The COFF backend has been converted to the new linker code. As with ELF, to
839 use the new linker, each particular target requires a relocation function. So
840 far, this function has been written for the i386, m68k, a29k and SH targets.
841
842 * The -V flag was made a synonym for -v, for SVR4 compatibility. The old -V
843 behaviour is available via --verbose.
844
845 Changes in version 2.4:
846
847 * New linker code, by Steve Chamberlain and Ian Taylor. For a.out and ecoff
848 formats (so far), this should result in considerable savings in time
849 and memory used while linking; slightly poorer performance than
850 before for formats not converted yet.
851
852 * Command-line parsing is no longer done with flex. This means
853 oddball characters in filenames won't get treated as argument
854 separators.
855
856 * HP-PA ELF support, by Jeff Law. (No SOM support yet.)
857
858 * Mach i386 support, by David Mackenzie.
859
860 * Irix 4 shared libraries are now supported (Irix 5 uses ELF, and ELF shared
861 libraries are not yet supported).
862
863 * COFF shared libraries (as on SCO) should work as well.
864
865 * The linker is disabled for Solaris. (Actually, it was in 2.3 also, I just
866 forgot to note it.) Some of their C library routines don't work when
867 statically linked, and the GNU linker doesn't support dynamic linking yet.
868
869 Changes in version 2.3:
870
871 * Weak symbols are now supported.
872
873 * ELF support has been added. The linker has been bootstrapped on
874 UnixWare and Solaris.
875
876 * Alpha OSF/1 support has been added (non dynamic linking only).
877
878 Changes in version 2.2:
879
880 * The `bfd' library has been updated to reduce a.out-format string
881 table size. The effect of this is that files linked from many input
882 files with duplicate symbols (`-g' debugging records, or identical
883 static symbols) should be much smaller.
884
885 Changes in version 2.1:
886
887 * The ld -ySYMBOL flag (to trace references to SYMBOL) is now implemented.
888
889 * There is now support for writing ECOFF files, so ld and the
890 other utilities should work on Risc/Ultrix and Irix.
891
892 \f
893 Copyright (C) 2012-2022 Free Software Foundation, Inc.
894
895 Copying and distribution of this file, with or without modification,
896 are permitted in any medium without royalty provided the copyright
897 notice and this notice are preserved.
898
899 Local variables:
900 fill-column: 79
901 End: