ld: Add -fno-lto to linker tests
[binutils-gdb.git] / ld / NEWS
1 -*- text -*-
2
3 * The linker now deduplicates the types in .ctf sections. The new
4 command-line option --ctf-share-types describes how to do this:
5 its default value, share-unconflicted, produces the most compact
6 output.
7
8 * The linker now omits the "variable section" from .ctf sections by
9 default, saving space. This is almost certainly what you want
10 unless you are working on a project that has its own analogue
11 of symbol tables that are not reflected in the ELF symtabs.
12
13 Changes in 2.35:
14
15 * X86 NaCl target support is removed.
16
17 * Add ELF linker command-line options, --export-dynamic-symbol and
18 --export-dynamic-symbol-list, to make symbols dynamic.
19
20 * Add a configure option, --enable-textrel-check=[no|yes|warning|error],
21 to decide what ELF linker should do by default with DT_TEXTREL in an
22 executable or shared library. Default to yes for Linux/x86 targets.
23
24 * The -Map=<filename> command line option has been extended so that if
25 <filename> is a directory then <filename>/<output-filename>.map will be
26 created.
27
28 * Add a command-line option for ELF linker, --warn-textrel, to warn that
29 DT_TEXTREL is set in a position-independent executable or shared object.
30
31 * Add command-line options --enable-non-contiguous-regions and
32 --enable-non-contiguous-regions-warnings.
33
34 * Add command-line option --imagic for the pdp11-aout target to output format
35 IMAGIC (0411) for separate instruction and data spaces, and change the
36 default format option for pdp11-aout to be --omagic.
37
38 * Relative pathnames in INPUT() and GROUP() directives in linker scripts are
39 searched relative to the directory of the linker script before other search
40 paths.
41
42 * Add ELF linker command-line option `-z start-stop-visibility=...' to control
43 the visibility of synthetic `__start_SECNAME` and `__stop_SECNAME` symbols.
44
45 * Add command-line option --dependency-file to write a Make-style dependency
46 file listing the input files consulted by the linker, like the files written
47 by the compiler's -M -MP options.
48
49 Changes in 2.34:
50
51 * The ld check for "PHDR segment not covered by LOAD segment" is more
52 effective, catching cases that were wrongly allowed by previous versions of
53 ld. If you see this error it is likely you are linking with a bad linker
54 script or the binary you are building is not intended to be loaded by a
55 dynamic loader. In the latter case --no-dynamic-linker is appropriate.
56
57 * cr16c support removed.
58
59 * Add support for z80-elf.
60
61 * Add support for relocation of each byte or word of multibyte value to Z80
62 targets.
63
64 * Add support for Zilog eZ80 (both ADL and Z80 mode) and Zilog Z180 CPUs.
65
66 Changes in 2.33:
67
68 * Add command-line option --no-print-map-discarded.
69
70 * The Cortex-A53 Erratum 843419 workaround now supports a choice of which
71 workaround to use. The option --fix-cortex-a53-843419 now takes an
72 optional argument --fix-cortex-a53-843419[=full|adr|adrp] which can be
73 used to force a particular workaround to be used. See --help for AArch64
74 for more details.
75
76 * Add target handlers for AArch64 for ELF GNU program properties.
77
78 * Add support for GNU_PROPERTY_AARCH64_FEATURE_1_BTI in ELF GNU program
79 properties in the AArch64 ELF linker.
80
81 * Add support for GNU_PROPERTY_AARCH64_FEATURE_1_PAC in ELF GNU program
82 properties in the AArch64 ELF linker.
83
84 * Add -z force-bti for AArch64 to enable GNU_PROPERTY_AARCH64_FEATURE_1_BTI
85 on output while warning about missing GNU_PROPERTY_AARCH64_FEATURE_1_BTI
86 on inputs and use PLTs protected with BTI.
87
88 * Add -z pac-plt for AArch64 to pick PAC enabled PLTs.
89
90 Changes in 2.32:
91
92 * Report property change in linker map file when merging GNU properties.
93
94 * Add support for the C-SKY processor series.
95
96 * -t now doesn't report members within archives, unless -t is given twice.
97 A single -t is now more useful when generating a list of files that should be
98 packaged for a linker bug report. For example:
99 gcc hello.c -save-temps -Wl,-t | xargs realpath | sort | uniq > files
100 tar cJf test.tar.xz `cat files`
101
102 Changes in 2.31:
103
104 * Speed up direct linking with DLLs for Cygwin and Mingw targets.
105
106 * Add a configure option --enable-separate-code to decide whether
107 -z separate-code should be enabled in ELF linker by default. Default
108 to yes for Linux/x86 targets. Note that -z separate-code can increase
109 disk and memory size.
110
111 Changes in 2.30:
112
113 * Add -z separate-code to generate separate code PT_LOAD segment.
114
115 * Add "-z undefs" command-line option as the inverse of the "-z defs" option.
116
117 * Add -z globalaudit command-line option to force audit libraries to be run
118 for every dynamic object loaded by an executable - provided that the loader
119 supports this functionality.
120
121 * Tighten linker script grammar around file name specifiers to prevent the use
122 of SORT_BY_ALIGNMENT and SORT_BY_INIT_PRIORITY on filenames. These would
123 previously be accepted but had no effect.
124
125 * The EXCLUDE_FILE directive can now be placed within any SORT_* directive
126 within input section lists.
127
128 Changes in 2.29:
129
130 * Support for -z shstk in the x86 ELF linker to generate
131 GNU_PROPERTY_X86_FEATURE_1_SHSTK in ELF GNU program properties.
132
133 * Add support for GNU_PROPERTY_X86_FEATURE_1_SHSTK in ELF GNU program
134 properties in the x86 ELF linker.
135
136 * Add support for GNU_PROPERTY_X86_FEATURE_1_IBT in ELF GNU program
137 properties in the x86 ELF linker.
138
139 * Support for -z ibtplt in the x86 ELF linker to generate IBT-enabled
140 PLT.
141
142 * Support for -z ibt in the x86 ELF linker to generate IBT-enabled
143 PLT as well as GNU_PROPERTY_X86_FEATURE_1_IBT in ELF GNU program
144 properties.
145
146 * Add support for ELF SHF_GNU_MBIND and PT_GNU_MBIND_XXX.
147
148 * Add support for ELF GNU program properties.
149
150 * Add support for the Texas Instruments PRU processor.
151
152 * When configuring for arc*-*-linux* targets the default linker emulation will
153 change if --with-cpu=nps400 is used at configure time.
154
155 * Improve assignment of LMAs to orphan sections in some edge cases where a
156 mixture of both AT>LMA_REGION and AT(LMA) are used.
157
158 * Orphan sections placed after an empty section that has an AT(LMA) will now
159 take an load memory address starting from LMA.
160
161 * Section groups can now be resolved (the group deleted and the group members
162 placed like normal sections) at partial link time either using the new linker
163 option --force-group-allocation or by placing FORCE_GROUP_ALLOCATION into the
164 linker script.
165
166 Changes in 2.28:
167
168 * The EXCLUDE_FILE linker script construct can now be applied outside of the
169 section list in order for the exclusions to apply over all input sections in
170 the list.
171
172 * Add support for the RISC-V architecture.
173
174 * The command-line option --no-eh-frame-hdr can now be used in ELF based
175 linkers to disable the automatic generation of .eh_frame_hdr sections.
176
177 * Add --in-implib=<infile> to the ARM linker to enable specifying a set of
178 Secure Gateway veneers that must exist in the output import library specified
179 by --out-implib=<outfile> and the address they must have. As such,
180 --in-implib is only supported in combination with --cmse-implib.
181
182 * Extended the --out-implib=<file> option, previously restricted to x86 PE
183 targets, to any ELF based target. This allows the generation of an import
184 library for an ELF executable, which can then be used by another application
185 to link against the executable.
186
187 Changes in 2.27:
188
189 * Add a configure option --enable-relro to decide whether -z relro should
190 be enabled in ELF linker by default. Default to yes for all Linux
191 targets except FRV, HPPA, IA64 and MIPS. Note that -z relro can increase
192 disk and memory size.
193
194 * Support for -z noreloc-overflow in the x86-64 ELF linker to disable
195 relocation overflow check.
196
197 * Add -z common/-z nocommon options for ELF targets to control whether to
198 convert common symbols to the STT_COMMON type during a relocatable link.
199
200 * Support for -z nodynamic-undefined-weak in the x86 ELF linker, which
201 avoids dynamic relocations against undefined weak symbols in executable.
202
203 * The NOCROSSREFSTO command was added to the linker script language.
204
205 * Add --no-apply-dynamic-relocs to the AArch64 linker to do not apply link-time
206 values for dynamic relocations.
207
208 Changes in 2.26:
209
210 * Add --fix-stm32l4xx-629360 to the ARM linker to enable a link-time
211 workaround for a bug in the bus matrix / memory controller for some of
212 the STM32 Cortex-M4 based products (STM32L4xx)
213
214 * Add a configure option --enable-compressed-debug-sections={all,ld} to
215 decide whether DWARF debug sections should be compressed by default.
216
217 * Add support for the ARC EM/HS, and ARC600/700 architectures.
218
219 * Experimental support for linker garbage collection (--gc-sections)
220 has been enabled for COFF and PE based targets.
221
222 * New command-line option for ELF targets to compress DWARF debug
223 sections, --compress-debug-sections=[none|zlib|zlib-gnu|zlib-gabi].
224
225 * New command-line option, --orphan-handling=[place|warn|error|discard], to
226 adjust how orphan sections are handled. The default is 'place' which gives
227 the current behaviour, 'warn' and 'error' issue a warning or error
228 respectively when orphan sections are found, and 'discard' will discard all
229 orphan sections.
230
231 * Add support for LLVM plugin.
232
233 * Add --print-memory-usage option to report memory blocks usage.
234
235 * Add --require-defined option, it's like --undefined except the new symbol
236 must be defined by the end of the link.
237
238 Changes in 2.25:
239
240 * PE binaries now once again contain real timestamps by default. To disable
241 the inclusion of a timestamp in a PE binary, use the --no-insert-timestamp
242 command-line option.
243
244 * Replace support for openrisc and or32 with support for or1k.
245
246 * Add support for the --build-id command-line option to COFF based targets.
247
248 * x86/x86_64 pe-coff now supports the --build-id option.
249
250 * Add support for the Andes NDS32.
251
252 Changes in 2.24:
253
254 * Add LOG2CEIL() builtin function to the linker script language
255
256 * Add support for the Texas Instruments MSP430X processor.
257
258 * Add support for Altera Nios II.
259
260 * Add support for the V850E3V5 architecture.
261
262 * Add support for the Imagination Technologies Meta processor.
263
264 * --enable-new-dtags no longer generates old dtags in addition to new dtags.
265
266 * Remove linker support for MIPS ECOFF targets.
267
268 * Add ALIGN_WITH_INPUT to the linker script language to force the alignment of
269 an output section to use the maximum alignment of all its input sections.
270
271 Changes in 2.23:
272
273 * Enable compressed debug section feature for x86/x86_64 pe-coff.
274
275 * Add support for the 64-bit ARM architecture: AArch64.
276
277 * Added SORT_NONE to the linker script language to disable section sorting.
278
279 * Add a linker-provided symbol when producing ELF output, '__ehdr_start'
280 to point to the ELF file header (and nearby program headers) in the
281 program's memory image.
282
283 * Add support for S12X processor.
284
285 * Add support for the VLE extension to the PowerPC architecture.
286
287 * Add support for the Freescale XGATE architecture.
288
289 * Add option -f FILE on AIX (for response file).
290
291 * Add support for the Renesas RL78 architecture.
292
293 * Add support for the Adapteva EPIPHANY architecture.
294
295 Changes in 2.22:
296
297 * --copy-dt-needed-entries is no longer enabled by default. Instead
298 --no-copy-dt-needed-entries is the default.
299
300 * INPUT_SECTION_FLAGS has been added to the linker script language
301 to allow selection of input sections by section header section flags.
302
303 * Add support for the Tilera TILEPro and TILE-Gx architectures.
304
305 * Added SORT_BY_INIT_PRIORITY to the linker script language to permit
306 sorting sections by numerical value of the GCC init_priority attribute
307 encoded in the section name.
308
309 Changes in 2.21:
310
311 * Linker script expression evaluation is somewhat more sane. This may
312 break scripts that depend on quirks of the old expression evaluation.
313
314 * Turn off underscoring for x86_64 PE+-COFF targets. For old behavior the
315 option --enable-leading-mingw64-underscores can be used on configure of
316 bfd.
317
318 * Add support for the TMS320C6000 (TI C6X) processor family.
319
320 * --add-needed renamed to --copy-dt-needed-entries in order to avoid confusion
321 with --as-needed option.
322
323 * Extend .def file syntax by '== <ID>' for imports and exports. This allows
324 to alias the import/export table name written in PE image.
325
326 * Add --exclude-all-symbols option to PE based linkers. This prevents all
327 symbols from automatically being exported.
328
329 * Add support for the Renesas RX processor.
330
331 * Add support for alpha-vms target.
332
333 Changes in 2.20:
334
335 * GNU/Linux targets now support the STB_GNU_UNIQUE symbol binding. This is a
336 GNU extension to the standard set of ELF symbol bindings. The binding will
337 be passed on to the dynamic linker which will make sure that in the entire
338 process there is just one symbol with the given name and type in use.
339
340 * PE targets now support a GNU extension to allow the alignment of common
341 common symbols to be specified. This support uses custom options in
342 the .drectve section, which will be disregarded by the native tools.
343
344 * PE targets now add primitive support for ELF version scripts; symbols
345 are not versioned, but the local and global symbol visibility directives
346 are respected when filtering symbols in auto-export mode.
347
348 * New option --no-export-dynamic to undo the effect of the -E and
349 --export-dynamic options.
350
351 * ELF: --warn-alternate-em option to warn if an object has alternate
352 ELF machine code.
353
354 * New script function REGION_ALIAS to add alias names to memory regions.
355
356 * PE targets no longer make use of the long section names PE extension to
357 the COFF format when generating executable images, by default. The old
358 (slightly non-conformant) behaviour can still be invoked by using the
359 new '--enable-long-section-names' command-line option. It is also enabled
360 automatically in the presence of un-stripped debug information, as GDB
361 needs to be able to find the debug info sections by their full names.
362
363 * For GNU/Linux systems the linker will now avoid processing any relocations
364 made against symbols of the STT_GNU_IFUNC type and instead emit them into
365 the resulting binary for processing by the loader.
366
367 * --as-needed now links in a dynamic library if it satisfies undefined
368 symbols in regular objects, or in other dynamic libraries. In the
369 latter case the library is not linked if it is found in a DT_NEEDED
370 entry of one of the libraries already linked.
371
372 * Add a new command-line option, -Ttext-segment ADDR, for ELF targets
373 to set the address of the first byte of the text segment.
374
375 * Add support for Sunplus score architecture.
376
377 * Add new option --use-nul-prefixed-import-tables to ld for PE targets to
378 allow fallback to old import table generation with null element prefix.
379
380 * Windows PE systems now support a new --exclude-modules-for-implib option,
381 allowing users to partition object files and archive members between a DLL
382 and its associated import library as they are generated during linking.
383
384 * Add support for Lattice Mico32 (lm32) architecture.
385
386 * Add CR16 ELF --embedded-relocs (used to embedded relocations into binaries
387 for Embedded-PIC code) option.
388
389 * Add to the PE/PE+ targets the support of two different kinds of
390 pseudo-relocations. They can be selected by the switches
391 --enable-runtime-pseudo-reloc-v1 and --enable-runtime-pseudo-reloc-v2.
392 For the switch --enable-runtime-pseudo-reloc it uses for 32-bit
393 runtime pseudo relocation version one, for 64-bit the version two.
394
395 Changes in 2.19:
396
397 * Linker scripts support a new INSERT command that makes it easier to
398 augment the default script.
399
400 * Linker script input section filespecs may now specify a file within an
401 archive by writing "archive:file".
402
403 * The --sort-common switch now has an optional argument which specifies the
404 direction of sorting.
405
406 * The M68K linker now supports multiple GOT generation schemes controlled via
407 the --got=<type> command-line option.
408
409 * The ARM EABI linker will now generate stubs for function calls to symbols
410 that are too far away. The placement of the stubs is controlled by a new
411 linker command-line option: --stub-group-size=N.
412
413 Changes in 2.18:
414
415 * Linker sources now released under version 3 of the GNU General Public
416 License.
417
418 * ELF: New --build-id option to generate a unique per-binary identifier
419 embedded in a note section.
420
421 * Added support for National Semicondutor CompactRISC (ie CR16) target.
422
423 * -l:foo now searches the library path for a filename called foo,
424 without converting it to libfoo.a or libfoo.so.
425
426 * Add a new command-line option '--default-script=FILE' or '-dT FILE'
427 which specifies a replacement for the built in, default linker
428 script.
429
430 * ELF: Add -Bsymbolic-functions, --dynamic-list-cpp-new, which puts C++
431 operator new and delete on the dynamic list, and --dynamic-list-data,
432 builtin list for --dynamic-list, which puts global data symbols on the
433 dynamic list.
434
435 * Add support for x86_64 PE+ target.
436
437 * Add support for Score target.
438
439 * ELF: Add --dynamic-list option to specify a list of global symbols
440 whose references shouldn't be bound to the definition within the
441 shared library, or a list of symbols which should be added to the
442 symbol table in the executable.
443
444 * The default output section LMA has changed for allocatable sections from
445 being equal to VMA, to keeping the difference between LMA and VMA the same as
446 the previous output section in the same region. This is a more useful
447 default when using overlays and other cases where you specify an LMA
448 differing from the VMA for some sections.
449
450 * New switch: --print-gc-sections to list any sections removed by garabge
451 collection.
452
453 * ARM: Added --vfp11-denorm-fix option to work around an erratum in current
454 VFP11 coprocessors.
455
456 Changes in 2.17:
457
458 * Support for the Infineon XC16X has been added by KPIT Cummins Infosystems.
459
460 * Modify the Linux linker search order to better match ld.so search order.
461 Look for DT_NEEDED libraries in paths specified by ld.so.conf before
462 searching the default directories, rather than vice versa.
463 Use $prefix/etc/ld.so.conf if it exists, otherwise /etc/ld.so.conf.
464
465 * PE-COFF: Forward exports from DLL's can now be specified in .def files
466 passed directly to ld.
467
468 * Support for the Z80 processor family has been added.
469
470 * Add support for the "@<file>" syntax to the command line, so that extra
471 switches can be read from <file>.
472
473 Changes in 2.16:
474
475 * Support for the R_ARM_V4BX relocation as defined in the ARM AAELF
476 specification has been added via the --fix-v4bx command-line option.
477
478 * New linker script construct AS_NEEDED(), which sets the --as-needed flag
479 for input files listed inside of it.
480
481 * A new command-line option, --sysroot, can be used to override the
482 default sysroot location. It only applies to toolchains that were
483 configured using --with-sysroot.
484
485 * New linker script functions: ORIGIN() and LENGTH() which return information
486 about a specified memory region.
487
488 * Port to MAXQ processor contributed by HCL Tech.
489
490 * Added SEGMENT_START to the linker script language to permit the user to
491 override the base address for a segment from the command-line.
492
493 * ELF: --warn-shared-textrel option to warn if adding a DT_TEXTREL to a shared
494 object.
495
496 * Added SORT_BY_NAME and SORT_BY_ALIGNMENT to the linker script
497 language to permit sorting sections by section name or section
498 maximum alignment.
499
500 * Added a new linker command-line switch, --sort-section name|alignment,
501 to sort sections by section name or maximum alignment.
502
503 * ELF: --add-needed/--no-add-needed options to control if a DT_NEEDED tag
504 should be added when a shared library comes from DT_NEEDED tags.
505
506 * Support for the crx-elf target added.
507
508 * Support for the sh-symbianelf target added.
509
510 * A new linker command-line switch has been added which allows the hash table
511 size to be set to a suitable prime value near to its argument. This switch
512 is --hash-size=<NUMBER>. Also if the switch --reduce-memory-overheads is
513 used, and --hash-size has not been used, then the default value will be set
514 to 1021.
515
516 * Linker map files are now generated with an O(N) algorithm for finding symbols
517 that are defined in each section. This uses about 40% more memory for
518 symbols than the old O(N^2) algorithm. You can use the new
519 --reduce-memory-overheads option to select the old algorithm; this option
520 might also be used in the future to select similar tradeoffs.
521
522 Changes in 2.15:
523
524 * ELF: --as-needed/--no-as-needed options to control if a DT_NEEDED tag should
525 be added only when a shared library is referenced.
526
527 * PE: --large-address-aware option to indicate executables support virtual
528 addresses greater than 2 gigabytes.
529
530 * DWARF 2 support for i386pe added.
531
532 * The linker script operator DEFINED() will now yield 1 only for a symbol that
533 is defined before the statement where DEFINED is used.
534
535 * The MIPS --embedded-relocs (used to embed relocations into binaries for
536 Embedded-PIC code) is deprecated and will be removed in a future release.
537
538 * cr16c support added by NSC.
539
540 * m32r Linux (ELF) support added by Renesas.
541
542 * Improved linker's handling of unresolved symbols. The switch
543 --unresolved-symbols=<method> has been added to tell the linker when it
544 should report them and the switch --warn-unresolved-symbols has been added to
545 make reports be issued as warning messages rather than errors.
546
547 Changes in 2.14:
548
549 * Added support for Xtensa architecture.
550
551 * Added --with-sysroot configure switch to specify a target system root, for
552 linking against a target filesystem image.
553
554 * Added --accept-unknown-linker-format to restore old linker behaviour (pre
555 2.14) of silently accepting and linking in any files in an unknown binary
556 file format.
557
558 * Added --no-omagic to undo the effects of the -N option.
559
560 * Support for Texas Instruments TMS320C4x and TMS320C3x series of
561 DSP's contributed by Michael Hayes and Svein E. Seldal.
562
563 * Added --with-lib-path configure switch to specify default value for
564 LIB_PATH.
565
566 * ARM port to QNX operating system added by Graeme Peterson.
567
568 * IP2K support added by Denis Chertykov.
569
570 Changes in 2.13:
571
572 * Support for the Fujitsu FRV architecture added by Red Hat. Models for FR400
573 and FR500 included.
574
575 Changes in version 2.13:
576
577 * DEC VAX ELF support, by Matt Thomas.
578
579 Changes in version 2.12:
580
581 * Support for Don Knuth's MMIX, by Hans-Peter Nilsson.
582
583 * Support for the OpenRISC 32-bit embedded processor by OpenCores.
584
585 * Support for -z nocopyreloc in the x86 ELF linker, which disables
586 production of copy relocs. Warning: using this option may result in
587 non-sharable applications.
588
589 * Support for -z combreloc in the ELF linker, which puts dynamic
590 relocations against the same symbol together, so that dynamic linker
591 can use an one-entry symbol lookup cache.
592
593 * Support for ELF SHF_MERGE section merging, by Jakub Jelinek.
594
595 Changes in version 2.11:
596
597 * Support for AMD x86-64 architecture, by Jan Hubicka, SuSE Labs.
598
599 * Support added for eliminating duplicate DWARF2 debug information by
600 having the compiler generate the information in sections called
601 .gnu.linkonce.wi.XXXX where XXXX is a checksum for the contents. The
602 linker then merges these sections together into the normal .debug_info
603 section.
604
605 * The native ELF linker now searches the directories in DT_RUNPATH or
606 DT_RPATH of a shared library for shared libraries needed by it.
607
608 * TI C54x support, by Timothy Wall.
609
610 * Added command-line switch --section-start to set the start address of any
611 specified section.
612
613 * Added ability to emit full relocation information in linked executables,
614 enabled by --emit-relocs. Some post-linkage optimization tools need
615 this information in order to be able to correctly identify and perform
616 symbol relative addressing in the event of changes in section contents
617 (instructions being added or deleted, extending data sections, etc.)
618
619 * Support for i860, by Jason Eckhardt (preliminary, alpha quality).
620
621 * Support for CRIS (Axis Communications ETRAX series).
622
623 * Support for PDP-11 and 2.11BSD a.out format, by Lars Brinkhoff.
624
625 Changes in version 2.10:
626
627 * Added AT> to the linker script language to allow load-time allocation of
628 sections into regions.
629
630 * Added garbage collection of unused sections, enabled by --gc-sections.
631 It does require a bit of backend support; currently implemented are
632 arm-elf, avr-elf, d10v-elf, fr30-elf, i386-elf, m32r-elf, m68k-elf,
633 mcore-elf, mips-elf, mn10300-elf, ppc-elf, sh-elf, sparc-elf, and v850-elf.
634 Others will ignore the option.
635
636 * Added SORT to the linker script language to permit sorting sections by file
637 name or section name.
638
639 * Added EXTERN to the linker script language as an equivalent to the -u
640 command-line option.
641
642 * Added ASSERT to the linker script language.
643
644 * Added EXCLUDE_FILE to the linker script language for further control over
645 wildcard file names.
646
647 * Added -O option to optimize linker output (as of this writing, this only
648 affects ELF shared library generation).
649
650 * The -e option now accepts a number as well as a symbol name.
651
652 * Added --no-undefined option to disallow undefined symbols when creating a
653 shared library.
654
655 * The linker now issues a warning, not an error, for an undefined symbol when
656 using -Bsymbolic; use the new --no-undefined option to get the old
657 behaviour.
658
659 * Added --demangle and --no-demangle options.
660
661 Changes in version 2.9:
662
663 * Added SQUAD to the linker script language.
664
665 * New option --no-warn-mismatch.
666
667 * The MEMORY command now parses the attributes to determine where sections that
668 are not placed in a specific memory region are placed.
669
670 Changes in version 2.8:
671
672 * Linker scripts may now contain shell wildcard characters for file and section
673 names.
674
675 * The linker now supports symbol versions in ELF.
676
677 * The NOCROSSREFS command was added to the linker script language.
678
679 * The LOADADDR expression was added to the linker script language.
680
681 * MAX and MIN functions were added to the linker script language.
682
683 * The OVERLAY construct was added to the linker script language.
684
685 * New option --warn-section-align to warn when the address of an output section
686 changes due to alignment of an input section.
687
688 * New options --filter/-F and --auxiliary/-f.
689
690 Changes in version 2.7:
691
692 * New option --cref to print out a cross reference table.
693
694 * New option --wrap SYMBOL.
695
696 * New option --no-whole-archive, to turn off the effect of --whole-archive.
697
698 * Input sections assigned to the output section /DISCARD/ in the linker script
699 are not included in the output file.
700
701 * The SunOS and ELF linkers now merge stabs debugging information which uses
702 the N_BINCL and N_EINCL stab types. This reduces the amount of debugging
703 information generated.
704
705 Changes in version 2.6:
706
707 * When an ELF section name is representable as a C identifier (this is not true
708 of most ELF section names), the linker will automatically define symbols
709 __start_SECNAME and __stop_SECNAME, where SECNAME is the section name, at the
710 beginning and the end of the section. This is used by glibc.
711
712 Addendum: Current versions of the linker (at least for version 2.18 onwards
713 and possibly much earlier as well) place two restrictions on this feature: The
714 symbols are only implemented for orphaned sections, not for explicitly placed
715 sections and they are PROVIDEd rather than being defined.
716
717 * When an ELF section named .gnu.warning is encountered in an input file, the
718 contents of the section are displayed as an error message, and the section is
719 not copied into the output file. This is used by glibc.
720
721 * When an ELF section named .gnu.warning.SYMBOL is encountered in an input
722 file, and the symbol SYMBOL is referenced by some object file, the contents of
723 the section are displayed as an error message. The section is not copied into
724 the output file, unless doing a relocatable or shared link. This is used by
725 glibc.
726
727 * New options -split-by-reloc and -split-by-file.
728
729 * The linker now supports linking PIC compiled code on SPARC SunOS. It can
730 also create SPARC SunOS shared libraries, and, like the native SunOS linker,
731 will do so whenever there is an undefined symbol in the link and neither the -e
732 nor the -r option was used.
733
734 * The -rpath option may be used on SunOS to set the list of directories to be
735 searched at run time. This overrides the default of building the list from the
736 -L options.
737
738 * The COFF linker now combines debugging information for structs, unions, and
739 enums, so that even if the same type is defined in multiple input files it will
740 only be defined once in the output file. The --traditional-format switch will
741 prevent this optimization.
742
743 Changes in version 2.5:
744
745 * The linker now supports linking against SunOS shared libraries. It still can
746 not link SunOS PIC (Position Independent Code) files, so it can not be used to
747 generate shared libraries.
748
749 * The linker now supports linking against ELF shared libraries for the i386
750 (UnixWare) and SPARC (Solaris). It can also link ELF PIC files, and can be
751 used to generate shared libraries. Shared library generation is not well
752 tested; please report any problems encountered. The linker is now enabled for
753 Solaris again.
754
755 * Eric Youngdale has contributed Linux support code, including linking against
756 Linux a.out shared libraries. The linker produces Linux QMAGIC binaries.
757
758 * The ELF backend has been converted to the new linker code. To use the new
759 ELF linker, each particular target requires a relocation function. So far,
760 this function has been written for i386 (UnixWare), SPARC (Solaris) MIPS (Irix
761 5), and HPPA ELF targets.
762
763 * The -( (--start-group) and -) (--end-group) options have been added to
764 support searching a group of archives as though they were a single archive.
765 This can also be used in a linker script, as GROUP ( files ).
766
767 * When a file is named on the command line, and the linker does not recognize
768 it as an object file, the linker will now treat the file as a linker script
769 file. A linker script named in this way augments, but does not replace, the
770 default linker script.
771
772 * The -warn-once option was added. It causes the linker to only warn once per
773 undefined symbol, rather than once per reference.
774
775 * The COFF backend has been converted to the new linker code. As with ELF, to
776 use the new linker, each particular target requires a relocation function. So
777 far, this function has been written for the i386, m68k, a29k and SH targets.
778
779 * The -V flag was made a synonym for -v, for SVR4 compatibility. The old -V
780 behaviour is available via --verbose.
781
782 Changes in version 2.4:
783
784 * New linker code, by Steve Chamberlain and Ian Taylor. For a.out and ecoff
785 formats (so far), this should result in considerable savings in time
786 and memory used while linking; slightly poorer performance than
787 before for formats not converted yet.
788
789 * Command-line parsing is no longer done with flex. This means
790 oddball characters in filenames won't get treated as argument
791 separators.
792
793 * HP-PA ELF support, by Jeff Law. (No SOM support yet.)
794
795 * Mach i386 support, by David Mackenzie.
796
797 * Irix 4 shared libraries are now supported (Irix 5 uses ELF, and ELF shared
798 libraries are not yet supported).
799
800 * COFF shared libraries (as on SCO) should work as well.
801
802 * The linker is disabled for Solaris. (Actually, it was in 2.3 also, I just
803 forgot to note it.) Some of their C library routines don't work when
804 statically linked, and the GNU linker doesn't support dynamic linking yet.
805
806 Changes in version 2.3:
807
808 * Weak symbols are now supported.
809
810 * ELF support has been added. The linker has been bootstrapped on
811 UnixWare and Solaris.
812
813 * Alpha OSF/1 support has been added (non dynamic linking only).
814
815 Changes in version 2.2:
816
817 * The `bfd' library has been updated to reduce a.out-format string
818 table size. The effect of this is that files linked from many input
819 files with duplicate symbols (`-g' debugging records, or identical
820 static symbols) should be much smaller.
821
822 Changes in version 2.1:
823
824 * The ld -ySYMBOL flag (to trace references to SYMBOL) is now implemented.
825
826 * There is now support for writing ECOFF files, so ld and the
827 other utilities should work on Risc/Ultrix and Irix.
828
829 \f
830 Copyright (C) 2012-2020 Free Software Foundation, Inc.
831
832 Copying and distribution of this file, with or without modification,
833 are permitted in any medium without royalty provided the copyright
834 notice and this notice are preserved.
835
836 Local variables:
837 fill-column: 79
838 End: