sim: ppc: unify header & function & type tests too
[binutils-gdb.git] / ld / NEWS
1 -*- text -*-
2
3 * arm-symbianelf support removed.
4
5 * Add -z report-relative-reloc to x86 ELF linker to report dynamic
6 relative relocations.
7
8 * Add -z start-stop-gc to disable special treatment of __start_*/__stop_*
9 references when --gc-sections.
10
11 * Add -Bno-symbolic to cancel -Bsymbolic and -Bsymbolic-functions.
12
13 Changes in 2.36:
14
15 * Add libdep plugin, for linking dependencies of static libraries that
16 were recorded by ar in the __.LIBDEP archive member.
17
18 * Add --error-handling-script=<NAME> command line option to allow a helper
19 script to be invoked when an undefined symbol or a missing library is
20 encountered. This option can be suppressed via the configure time
21 switch: --enable-error-handling-script=no.
22
23 * Add -z lam-u48 to x86-64 ELF linker to generate LAM_U48 property.
24
25 * Add -z lam-u57 to x86-64 ELF linker to enerate LAM_U57 property.
26
27 * Add -z lam-u48-report=[none|warning|error] to report missing LAM_U48
28 property.
29
30 * Add -z lam-u57-report=[none|warning|error] to report missing LAM_U57
31 property.
32
33 * Add -z lam-report=[none|warning|error] to report missing LAM_U48 and
34 LAM_U57 properties.
35
36 * Add -z x86-64-{baseline|v[234]} to the x86 ELF linker to mark
37 x86-64-{baseline|v[234]} ISA level as needed.
38
39 * Add -z unique-symbol to avoid duplicated local symbol names.
40
41 * The creation of PE format DLLs now defaults to using a more secure set of DLL
42 characteristics.
43
44 * The linker now deduplicates the types in .ctf sections. The new
45 command-line option --ctf-share-types describes how to do this:
46 its default value, share-unconflicted, produces the most compact
47 output.
48
49 * The linker now omits the "variable section" from .ctf sections by
50 default, saving space. This is almost certainly what you want
51 unless you are working on a project that has its own analogue
52 of symbol tables that are not reflected in the ELF symtabs.
53
54 * Add support for the SHF_GNU_RETAIN ELF section flag.
55 This flag specifies that the section should not be garbage collected by the
56 linker.
57
58 Changes in 2.35:
59
60 * X86 NaCl target support is removed.
61
62 * Add ELF linker command-line options, --export-dynamic-symbol and
63 --export-dynamic-symbol-list, to make symbols dynamic.
64
65 * Add a configure option, --enable-textrel-check=[no|yes|warning|error],
66 to decide what ELF linker should do by default with DT_TEXTREL in an
67 executable or shared library. Default to yes for Linux/x86 targets.
68
69 * The -Map=<filename> command line option has been extended so that if
70 <filename> is a directory then <filename>/<output-filename>.map will be
71 created.
72
73 * Add a command-line option for ELF linker, --warn-textrel, to warn that
74 DT_TEXTREL is set in a position-independent executable or shared object.
75
76 * Add command-line options --enable-non-contiguous-regions and
77 --enable-non-contiguous-regions-warnings.
78
79 * Add command-line option --imagic for the pdp11-aout target to output format
80 IMAGIC (0411) for separate instruction and data spaces, and change the
81 default format option for pdp11-aout to be --omagic.
82
83 * Relative pathnames in INPUT() and GROUP() directives in linker scripts are
84 searched relative to the directory of the linker script before other search
85 paths.
86
87 * Add ELF linker command-line option `-z start-stop-visibility=...' to control
88 the visibility of synthetic `__start_SECNAME` and `__stop_SECNAME` symbols.
89
90 * Add command-line option --dependency-file to write a Make-style dependency
91 file listing the input files consulted by the linker, like the files written
92 by the compiler's -M -MP options.
93
94 Changes in 2.34:
95
96 * The ld check for "PHDR segment not covered by LOAD segment" is more
97 effective, catching cases that were wrongly allowed by previous versions of
98 ld. If you see this error it is likely you are linking with a bad linker
99 script or the binary you are building is not intended to be loaded by a
100 dynamic loader. In the latter case --no-dynamic-linker is appropriate.
101
102 * cr16c support removed.
103
104 * Add support for z80-elf.
105
106 * Add support for relocation of each byte or word of multibyte value to Z80
107 targets.
108
109 * Add support for Zilog eZ80 (both ADL and Z80 mode) and Zilog Z180 CPUs.
110
111 Changes in 2.33:
112
113 * Add command-line option --no-print-map-discarded.
114
115 * The Cortex-A53 Erratum 843419 workaround now supports a choice of which
116 workaround to use. The option --fix-cortex-a53-843419 now takes an
117 optional argument --fix-cortex-a53-843419[=full|adr|adrp] which can be
118 used to force a particular workaround to be used. See --help for AArch64
119 for more details.
120
121 * Add target handlers for AArch64 for ELF GNU program properties.
122
123 * Add support for GNU_PROPERTY_AARCH64_FEATURE_1_BTI in ELF GNU program
124 properties in the AArch64 ELF linker.
125
126 * Add support for GNU_PROPERTY_AARCH64_FEATURE_1_PAC in ELF GNU program
127 properties in the AArch64 ELF linker.
128
129 * Add -z force-bti for AArch64 to enable GNU_PROPERTY_AARCH64_FEATURE_1_BTI
130 on output while warning about missing GNU_PROPERTY_AARCH64_FEATURE_1_BTI
131 on inputs and use PLTs protected with BTI.
132
133 * Add -z pac-plt for AArch64 to pick PAC enabled PLTs.
134
135 Changes in 2.32:
136
137 * Report property change in linker map file when merging GNU properties.
138
139 * Add support for the C-SKY processor series.
140
141 * -t now doesn't report members within archives, unless -t is given twice.
142 A single -t is now more useful when generating a list of files that should be
143 packaged for a linker bug report. For example:
144 gcc hello.c -save-temps -Wl,-t | xargs realpath | sort | uniq > files
145 tar cJf test.tar.xz `cat files`
146
147 Changes in 2.31:
148
149 * Speed up direct linking with DLLs for Cygwin and Mingw targets.
150
151 * Add a configure option --enable-separate-code to decide whether
152 -z separate-code should be enabled in ELF linker by default. Default
153 to yes for Linux/x86 targets. Note that -z separate-code can increase
154 disk and memory size.
155
156 Changes in 2.30:
157
158 * Add -z separate-code to generate separate code PT_LOAD segment.
159
160 * Add "-z undefs" command-line option as the inverse of the "-z defs" option.
161
162 * Add -z globalaudit command-line option to force audit libraries to be run
163 for every dynamic object loaded by an executable - provided that the loader
164 supports this functionality.
165
166 * Tighten linker script grammar around file name specifiers to prevent the use
167 of SORT_BY_ALIGNMENT and SORT_BY_INIT_PRIORITY on filenames. These would
168 previously be accepted but had no effect.
169
170 * The EXCLUDE_FILE directive can now be placed within any SORT_* directive
171 within input section lists.
172
173 Changes in 2.29:
174
175 * Support for -z shstk in the x86 ELF linker to generate
176 GNU_PROPERTY_X86_FEATURE_1_SHSTK in ELF GNU program properties.
177
178 * Add support for GNU_PROPERTY_X86_FEATURE_1_SHSTK in ELF GNU program
179 properties in the x86 ELF linker.
180
181 * Add support for GNU_PROPERTY_X86_FEATURE_1_IBT in ELF GNU program
182 properties in the x86 ELF linker.
183
184 * Support for -z ibtplt in the x86 ELF linker to generate IBT-enabled
185 PLT.
186
187 * Support for -z ibt in the x86 ELF linker to generate IBT-enabled
188 PLT as well as GNU_PROPERTY_X86_FEATURE_1_IBT in ELF GNU program
189 properties.
190
191 * Add support for ELF SHF_GNU_MBIND and PT_GNU_MBIND_XXX.
192
193 * Add support for ELF GNU program properties.
194
195 * Add support for the Texas Instruments PRU processor.
196
197 * When configuring for arc*-*-linux* targets the default linker emulation will
198 change if --with-cpu=nps400 is used at configure time.
199
200 * Improve assignment of LMAs to orphan sections in some edge cases where a
201 mixture of both AT>LMA_REGION and AT(LMA) are used.
202
203 * Orphan sections placed after an empty section that has an AT(LMA) will now
204 take an load memory address starting from LMA.
205
206 * Section groups can now be resolved (the group deleted and the group members
207 placed like normal sections) at partial link time either using the new linker
208 option --force-group-allocation or by placing FORCE_GROUP_ALLOCATION into the
209 linker script.
210
211 Changes in 2.28:
212
213 * The EXCLUDE_FILE linker script construct can now be applied outside of the
214 section list in order for the exclusions to apply over all input sections in
215 the list.
216
217 * Add support for the RISC-V architecture.
218
219 * The command-line option --no-eh-frame-hdr can now be used in ELF based
220 linkers to disable the automatic generation of .eh_frame_hdr sections.
221
222 * Add --in-implib=<infile> to the ARM linker to enable specifying a set of
223 Secure Gateway veneers that must exist in the output import library specified
224 by --out-implib=<outfile> and the address they must have. As such,
225 --in-implib is only supported in combination with --cmse-implib.
226
227 * Extended the --out-implib=<file> option, previously restricted to x86 PE
228 targets, to any ELF based target. This allows the generation of an import
229 library for an ELF executable, which can then be used by another application
230 to link against the executable.
231
232 Changes in 2.27:
233
234 * Add a configure option --enable-relro to decide whether -z relro should
235 be enabled in ELF linker by default. Default to yes for all Linux
236 targets except FRV, HPPA, IA64 and MIPS. Note that -z relro can increase
237 disk and memory size.
238
239 * Support for -z noreloc-overflow in the x86-64 ELF linker to disable
240 relocation overflow check.
241
242 * Add -z common/-z nocommon options for ELF targets to control whether to
243 convert common symbols to the STT_COMMON type during a relocatable link.
244
245 * Support for -z nodynamic-undefined-weak in the x86 ELF linker, which
246 avoids dynamic relocations against undefined weak symbols in executable.
247
248 * The NOCROSSREFSTO command was added to the linker script language.
249
250 * Add --no-apply-dynamic-relocs to the AArch64 linker to do not apply link-time
251 values for dynamic relocations.
252
253 Changes in 2.26:
254
255 * Add --fix-stm32l4xx-629360 to the ARM linker to enable a link-time
256 workaround for a bug in the bus matrix / memory controller for some of
257 the STM32 Cortex-M4 based products (STM32L4xx)
258
259 * Add a configure option --enable-compressed-debug-sections={all,ld} to
260 decide whether DWARF debug sections should be compressed by default.
261
262 * Add support for the ARC EM/HS, and ARC600/700 architectures.
263
264 * Experimental support for linker garbage collection (--gc-sections)
265 has been enabled for COFF and PE based targets.
266
267 * New command-line option for ELF targets to compress DWARF debug
268 sections, --compress-debug-sections=[none|zlib|zlib-gnu|zlib-gabi].
269
270 * New command-line option, --orphan-handling=[place|warn|error|discard], to
271 adjust how orphan sections are handled. The default is 'place' which gives
272 the current behaviour, 'warn' and 'error' issue a warning or error
273 respectively when orphan sections are found, and 'discard' will discard all
274 orphan sections.
275
276 * Add support for LLVM plugin.
277
278 * Add --print-memory-usage option to report memory blocks usage.
279
280 * Add --require-defined option, it's like --undefined except the new symbol
281 must be defined by the end of the link.
282
283 Changes in 2.25:
284
285 * PE binaries now once again contain real timestamps by default. To disable
286 the inclusion of a timestamp in a PE binary, use the --no-insert-timestamp
287 command-line option.
288
289 * Replace support for openrisc and or32 with support for or1k.
290
291 * Add support for the --build-id command-line option to COFF based targets.
292
293 * x86/x86_64 pe-coff now supports the --build-id option.
294
295 * Add support for the Andes NDS32.
296
297 Changes in 2.24:
298
299 * Add LOG2CEIL() builtin function to the linker script language
300
301 * Add support for the Texas Instruments MSP430X processor.
302
303 * Add support for Altera Nios II.
304
305 * Add support for the V850E3V5 architecture.
306
307 * Add support for the Imagination Technologies Meta processor.
308
309 * --enable-new-dtags no longer generates old dtags in addition to new dtags.
310
311 * Remove linker support for MIPS ECOFF targets.
312
313 * Add ALIGN_WITH_INPUT to the linker script language to force the alignment of
314 an output section to use the maximum alignment of all its input sections.
315
316 Changes in 2.23:
317
318 * Enable compressed debug section feature for x86/x86_64 pe-coff.
319
320 * Add support for the 64-bit ARM architecture: AArch64.
321
322 * Added SORT_NONE to the linker script language to disable section sorting.
323
324 * Add a linker-provided symbol when producing ELF output, '__ehdr_start'
325 to point to the ELF file header (and nearby program headers) in the
326 program's memory image.
327
328 * Add support for S12X processor.
329
330 * Add support for the VLE extension to the PowerPC architecture.
331
332 * Add support for the Freescale XGATE architecture.
333
334 * Add option -f FILE on AIX (for response file).
335
336 * Add support for the Renesas RL78 architecture.
337
338 * Add support for the Adapteva EPIPHANY architecture.
339
340 Changes in 2.22:
341
342 * --copy-dt-needed-entries is no longer enabled by default. Instead
343 --no-copy-dt-needed-entries is the default.
344
345 * INPUT_SECTION_FLAGS has been added to the linker script language
346 to allow selection of input sections by section header section flags.
347
348 * Add support for the Tilera TILEPro and TILE-Gx architectures.
349
350 * Added SORT_BY_INIT_PRIORITY to the linker script language to permit
351 sorting sections by numerical value of the GCC init_priority attribute
352 encoded in the section name.
353
354 Changes in 2.21:
355
356 * Linker script expression evaluation is somewhat more sane. This may
357 break scripts that depend on quirks of the old expression evaluation.
358
359 * Turn off underscoring for x86_64 PE+-COFF targets. For old behavior the
360 option --enable-leading-mingw64-underscores can be used on configure of
361 bfd.
362
363 * Add support for the TMS320C6000 (TI C6X) processor family.
364
365 * --add-needed renamed to --copy-dt-needed-entries in order to avoid confusion
366 with --as-needed option.
367
368 * Extend .def file syntax by '== <ID>' for imports and exports. This allows
369 to alias the import/export table name written in PE image.
370
371 * Add --exclude-all-symbols option to PE based linkers. This prevents all
372 symbols from automatically being exported.
373
374 * Add support for the Renesas RX processor.
375
376 * Add support for alpha-vms target.
377
378 Changes in 2.20:
379
380 * GNU/Linux targets now support the STB_GNU_UNIQUE symbol binding. This is a
381 GNU extension to the standard set of ELF symbol bindings. The binding will
382 be passed on to the dynamic linker which will make sure that in the entire
383 process there is just one symbol with the given name and type in use.
384
385 * PE targets now support a GNU extension to allow the alignment of common
386 common symbols to be specified. This support uses custom options in
387 the .drectve section, which will be disregarded by the native tools.
388
389 * PE targets now add primitive support for ELF version scripts; symbols
390 are not versioned, but the local and global symbol visibility directives
391 are respected when filtering symbols in auto-export mode.
392
393 * New option --no-export-dynamic to undo the effect of the -E and
394 --export-dynamic options.
395
396 * ELF: --warn-alternate-em option to warn if an object has alternate
397 ELF machine code.
398
399 * New script function REGION_ALIAS to add alias names to memory regions.
400
401 * PE targets no longer make use of the long section names PE extension to
402 the COFF format when generating executable images, by default. The old
403 (slightly non-conformant) behaviour can still be invoked by using the
404 new '--enable-long-section-names' command-line option. It is also enabled
405 automatically in the presence of un-stripped debug information, as GDB
406 needs to be able to find the debug info sections by their full names.
407
408 * For GNU/Linux systems the linker will now avoid processing any relocations
409 made against symbols of the STT_GNU_IFUNC type and instead emit them into
410 the resulting binary for processing by the loader.
411
412 * --as-needed now links in a dynamic library if it satisfies undefined
413 symbols in regular objects, or in other dynamic libraries. In the
414 latter case the library is not linked if it is found in a DT_NEEDED
415 entry of one of the libraries already linked.
416
417 * Add a new command-line option, -Ttext-segment ADDR, for ELF targets
418 to set the address of the first byte of the text segment.
419
420 * Add support for Sunplus score architecture.
421
422 * Add new option --use-nul-prefixed-import-tables to ld for PE targets to
423 allow fallback to old import table generation with null element prefix.
424
425 * Windows PE systems now support a new --exclude-modules-for-implib option,
426 allowing users to partition object files and archive members between a DLL
427 and its associated import library as they are generated during linking.
428
429 * Add support for Lattice Mico32 (lm32) architecture.
430
431 * Add CR16 ELF --embedded-relocs (used to embedded relocations into binaries
432 for Embedded-PIC code) option.
433
434 * Add to the PE/PE+ targets the support of two different kinds of
435 pseudo-relocations. They can be selected by the switches
436 --enable-runtime-pseudo-reloc-v1 and --enable-runtime-pseudo-reloc-v2.
437 For the switch --enable-runtime-pseudo-reloc it uses for 32-bit
438 runtime pseudo relocation version one, for 64-bit the version two.
439
440 Changes in 2.19:
441
442 * Linker scripts support a new INSERT command that makes it easier to
443 augment the default script.
444
445 * Linker script input section filespecs may now specify a file within an
446 archive by writing "archive:file".
447
448 * The --sort-common switch now has an optional argument which specifies the
449 direction of sorting.
450
451 * The M68K linker now supports multiple GOT generation schemes controlled via
452 the --got=<type> command-line option.
453
454 * The ARM EABI linker will now generate stubs for function calls to symbols
455 that are too far away. The placement of the stubs is controlled by a new
456 linker command-line option: --stub-group-size=N.
457
458 Changes in 2.18:
459
460 * Linker sources now released under version 3 of the GNU General Public
461 License.
462
463 * ELF: New --build-id option to generate a unique per-binary identifier
464 embedded in a note section.
465
466 * Added support for National Semicondutor CompactRISC (ie CR16) target.
467
468 * -l:foo now searches the library path for a filename called foo,
469 without converting it to libfoo.a or libfoo.so.
470
471 * Add a new command-line option '--default-script=FILE' or '-dT FILE'
472 which specifies a replacement for the built in, default linker
473 script.
474
475 * ELF: Add -Bsymbolic-functions, --dynamic-list-cpp-new, which puts C++
476 operator new and delete on the dynamic list, and --dynamic-list-data,
477 builtin list for --dynamic-list, which puts global data symbols on the
478 dynamic list.
479
480 * Add support for x86_64 PE+ target.
481
482 * Add support for Score target.
483
484 * ELF: Add --dynamic-list option to specify a list of global symbols
485 whose references shouldn't be bound to the definition within the
486 shared library, or a list of symbols which should be added to the
487 symbol table in the executable.
488
489 * The default output section LMA has changed for allocatable sections from
490 being equal to VMA, to keeping the difference between LMA and VMA the same as
491 the previous output section in the same region. This is a more useful
492 default when using overlays and other cases where you specify an LMA
493 differing from the VMA for some sections.
494
495 * New switch: --print-gc-sections to list any sections removed by garabge
496 collection.
497
498 * ARM: Added --vfp11-denorm-fix option to work around an erratum in current
499 VFP11 coprocessors.
500
501 Changes in 2.17:
502
503 * Support for the Infineon XC16X has been added by KPIT Cummins Infosystems.
504
505 * Modify the Linux linker search order to better match ld.so search order.
506 Look for DT_NEEDED libraries in paths specified by ld.so.conf before
507 searching the default directories, rather than vice versa.
508 Use $prefix/etc/ld.so.conf if it exists, otherwise /etc/ld.so.conf.
509
510 * PE-COFF: Forward exports from DLL's can now be specified in .def files
511 passed directly to ld.
512
513 * Support for the Z80 processor family has been added.
514
515 * Add support for the "@<file>" syntax to the command line, so that extra
516 switches can be read from <file>.
517
518 Changes in 2.16:
519
520 * Support for the R_ARM_V4BX relocation as defined in the ARM AAELF
521 specification has been added via the --fix-v4bx command-line option.
522
523 * New linker script construct AS_NEEDED(), which sets the --as-needed flag
524 for input files listed inside of it.
525
526 * A new command-line option, --sysroot, can be used to override the
527 default sysroot location. It only applies to toolchains that were
528 configured using --with-sysroot.
529
530 * New linker script functions: ORIGIN() and LENGTH() which return information
531 about a specified memory region.
532
533 * Port to MAXQ processor contributed by HCL Tech.
534
535 * Added SEGMENT_START to the linker script language to permit the user to
536 override the base address for a segment from the command-line.
537
538 * ELF: --warn-shared-textrel option to warn if adding a DT_TEXTREL to a shared
539 object.
540
541 * Added SORT_BY_NAME and SORT_BY_ALIGNMENT to the linker script
542 language to permit sorting sections by section name or section
543 maximum alignment.
544
545 * Added a new linker command-line switch, --sort-section name|alignment,
546 to sort sections by section name or maximum alignment.
547
548 * ELF: --add-needed/--no-add-needed options to control if a DT_NEEDED tag
549 should be added when a shared library comes from DT_NEEDED tags.
550
551 * Support for the crx-elf target added.
552
553 * Support for the sh-symbianelf target added.
554
555 * A new linker command-line switch has been added which allows the hash table
556 size to be set to a suitable prime value near to its argument. This switch
557 is --hash-size=<NUMBER>. Also if the switch --reduce-memory-overheads is
558 used, and --hash-size has not been used, then the default value will be set
559 to 1021.
560
561 * Linker map files are now generated with an O(N) algorithm for finding symbols
562 that are defined in each section. This uses about 40% more memory for
563 symbols than the old O(N^2) algorithm. You can use the new
564 --reduce-memory-overheads option to select the old algorithm; this option
565 might also be used in the future to select similar tradeoffs.
566
567 Changes in 2.15:
568
569 * ELF: --as-needed/--no-as-needed options to control if a DT_NEEDED tag should
570 be added only when a shared library is referenced.
571
572 * PE: --large-address-aware option to indicate executables support virtual
573 addresses greater than 2 gigabytes.
574
575 * DWARF 2 support for i386pe added.
576
577 * The linker script operator DEFINED() will now yield 1 only for a symbol that
578 is defined before the statement where DEFINED is used.
579
580 * The MIPS --embedded-relocs (used to embed relocations into binaries for
581 Embedded-PIC code) is deprecated and will be removed in a future release.
582
583 * cr16c support added by NSC.
584
585 * m32r Linux (ELF) support added by Renesas.
586
587 * Improved linker's handling of unresolved symbols. The switch
588 --unresolved-symbols=<method> has been added to tell the linker when it
589 should report them and the switch --warn-unresolved-symbols has been added to
590 make reports be issued as warning messages rather than errors.
591
592 Changes in 2.14:
593
594 * Added support for Xtensa architecture.
595
596 * Added --with-sysroot configure switch to specify a target system root, for
597 linking against a target filesystem image.
598
599 * Added --accept-unknown-linker-format to restore old linker behaviour (pre
600 2.14) of silently accepting and linking in any files in an unknown binary
601 file format.
602
603 * Added --no-omagic to undo the effects of the -N option.
604
605 * Support for Texas Instruments TMS320C4x and TMS320C3x series of
606 DSP's contributed by Michael Hayes and Svein E. Seldal.
607
608 * Added --with-lib-path configure switch to specify default value for
609 LIB_PATH.
610
611 * ARM port to QNX operating system added by Graeme Peterson.
612
613 * IP2K support added by Denis Chertykov.
614
615 Changes in 2.13:
616
617 * Support for the Fujitsu FRV architecture added by Red Hat. Models for FR400
618 and FR500 included.
619
620 Changes in version 2.13:
621
622 * DEC VAX ELF support, by Matt Thomas.
623
624 Changes in version 2.12:
625
626 * Support for Don Knuth's MMIX, by Hans-Peter Nilsson.
627
628 * Support for the OpenRISC 32-bit embedded processor by OpenCores.
629
630 * Support for -z nocopyreloc in the x86 ELF linker, which disables
631 production of copy relocs. Warning: using this option may result in
632 non-sharable applications.
633
634 * Support for -z combreloc in the ELF linker, which puts dynamic
635 relocations against the same symbol together, so that dynamic linker
636 can use an one-entry symbol lookup cache.
637
638 * Support for ELF SHF_MERGE section merging, by Jakub Jelinek.
639
640 Changes in version 2.11:
641
642 * Support for AMD x86-64 architecture, by Jan Hubicka, SuSE Labs.
643
644 * Support added for eliminating duplicate DWARF2 debug information by
645 having the compiler generate the information in sections called
646 .gnu.linkonce.wi.XXXX where XXXX is a checksum for the contents. The
647 linker then merges these sections together into the normal .debug_info
648 section.
649
650 * The native ELF linker now searches the directories in DT_RUNPATH or
651 DT_RPATH of a shared library for shared libraries needed by it.
652
653 * TI C54x support, by Timothy Wall.
654
655 * Added command-line switch --section-start to set the start address of any
656 specified section.
657
658 * Added ability to emit full relocation information in linked executables,
659 enabled by --emit-relocs. Some post-linkage optimization tools need
660 this information in order to be able to correctly identify and perform
661 symbol relative addressing in the event of changes in section contents
662 (instructions being added or deleted, extending data sections, etc.)
663
664 * Support for i860, by Jason Eckhardt (preliminary, alpha quality).
665
666 * Support for CRIS (Axis Communications ETRAX series).
667
668 * Support for PDP-11 and 2.11BSD a.out format, by Lars Brinkhoff.
669
670 Changes in version 2.10:
671
672 * Added AT> to the linker script language to allow load-time allocation of
673 sections into regions.
674
675 * Added garbage collection of unused sections, enabled by --gc-sections.
676 It does require a bit of backend support; currently implemented are
677 arm-elf, avr-elf, d10v-elf, fr30-elf, i386-elf, m32r-elf, m68k-elf,
678 mcore-elf, mips-elf, mn10300-elf, ppc-elf, sh-elf, sparc-elf, and v850-elf.
679 Others will ignore the option.
680
681 * Added SORT to the linker script language to permit sorting sections by file
682 name or section name.
683
684 * Added EXTERN to the linker script language as an equivalent to the -u
685 command-line option.
686
687 * Added ASSERT to the linker script language.
688
689 * Added EXCLUDE_FILE to the linker script language for further control over
690 wildcard file names.
691
692 * Added -O option to optimize linker output (as of this writing, this only
693 affects ELF shared library generation).
694
695 * The -e option now accepts a number as well as a symbol name.
696
697 * Added --no-undefined option to disallow undefined symbols when creating a
698 shared library.
699
700 * The linker now issues a warning, not an error, for an undefined symbol when
701 using -Bsymbolic; use the new --no-undefined option to get the old
702 behaviour.
703
704 * Added --demangle and --no-demangle options.
705
706 Changes in version 2.9:
707
708 * Added SQUAD to the linker script language.
709
710 * New option --no-warn-mismatch.
711
712 * The MEMORY command now parses the attributes to determine where sections that
713 are not placed in a specific memory region are placed.
714
715 Changes in version 2.8:
716
717 * Linker scripts may now contain shell wildcard characters for file and section
718 names.
719
720 * The linker now supports symbol versions in ELF.
721
722 * The NOCROSSREFS command was added to the linker script language.
723
724 * The LOADADDR expression was added to the linker script language.
725
726 * MAX and MIN functions were added to the linker script language.
727
728 * The OVERLAY construct was added to the linker script language.
729
730 * New option --warn-section-align to warn when the address of an output section
731 changes due to alignment of an input section.
732
733 * New options --filter/-F and --auxiliary/-f.
734
735 Changes in version 2.7:
736
737 * New option --cref to print out a cross reference table.
738
739 * New option --wrap SYMBOL.
740
741 * New option --no-whole-archive, to turn off the effect of --whole-archive.
742
743 * Input sections assigned to the output section /DISCARD/ in the linker script
744 are not included in the output file.
745
746 * The SunOS and ELF linkers now merge stabs debugging information which uses
747 the N_BINCL and N_EINCL stab types. This reduces the amount of debugging
748 information generated.
749
750 Changes in version 2.6:
751
752 * When an ELF section name is representable as a C identifier (this is not true
753 of most ELF section names), the linker will automatically define symbols
754 __start_SECNAME and __stop_SECNAME, where SECNAME is the section name, at the
755 beginning and the end of the section. This is used by glibc.
756
757 Addendum: Current versions of the linker (at least for version 2.18 onwards
758 and possibly much earlier as well) place two restrictions on this feature: The
759 symbols are only implemented for orphaned sections, not for explicitly placed
760 sections and they are PROVIDEd rather than being defined.
761
762 * When an ELF section named .gnu.warning is encountered in an input file, the
763 contents of the section are displayed as an error message, and the section is
764 not copied into the output file. This is used by glibc.
765
766 * When an ELF section named .gnu.warning.SYMBOL is encountered in an input
767 file, and the symbol SYMBOL is referenced by some object file, the contents of
768 the section are displayed as an error message. The section is not copied into
769 the output file, unless doing a relocatable or shared link. This is used by
770 glibc.
771
772 * New options -split-by-reloc and -split-by-file.
773
774 * The linker now supports linking PIC compiled code on SPARC SunOS. It can
775 also create SPARC SunOS shared libraries, and, like the native SunOS linker,
776 will do so whenever there is an undefined symbol in the link and neither the -e
777 nor the -r option was used.
778
779 * The -rpath option may be used on SunOS to set the list of directories to be
780 searched at run time. This overrides the default of building the list from the
781 -L options.
782
783 * The COFF linker now combines debugging information for structs, unions, and
784 enums, so that even if the same type is defined in multiple input files it will
785 only be defined once in the output file. The --traditional-format switch will
786 prevent this optimization.
787
788 Changes in version 2.5:
789
790 * The linker now supports linking against SunOS shared libraries. It still can
791 not link SunOS PIC (Position Independent Code) files, so it can not be used to
792 generate shared libraries.
793
794 * The linker now supports linking against ELF shared libraries for the i386
795 (UnixWare) and SPARC (Solaris). It can also link ELF PIC files, and can be
796 used to generate shared libraries. Shared library generation is not well
797 tested; please report any problems encountered. The linker is now enabled for
798 Solaris again.
799
800 * Eric Youngdale has contributed Linux support code, including linking against
801 Linux a.out shared libraries. The linker produces Linux QMAGIC binaries.
802
803 * The ELF backend has been converted to the new linker code. To use the new
804 ELF linker, each particular target requires a relocation function. So far,
805 this function has been written for i386 (UnixWare), SPARC (Solaris) MIPS (Irix
806 5), and HPPA ELF targets.
807
808 * The -( (--start-group) and -) (--end-group) options have been added to
809 support searching a group of archives as though they were a single archive.
810 This can also be used in a linker script, as GROUP ( files ).
811
812 * When a file is named on the command line, and the linker does not recognize
813 it as an object file, the linker will now treat the file as a linker script
814 file. A linker script named in this way augments, but does not replace, the
815 default linker script.
816
817 * The -warn-once option was added. It causes the linker to only warn once per
818 undefined symbol, rather than once per reference.
819
820 * The COFF backend has been converted to the new linker code. As with ELF, to
821 use the new linker, each particular target requires a relocation function. So
822 far, this function has been written for the i386, m68k, a29k and SH targets.
823
824 * The -V flag was made a synonym for -v, for SVR4 compatibility. The old -V
825 behaviour is available via --verbose.
826
827 Changes in version 2.4:
828
829 * New linker code, by Steve Chamberlain and Ian Taylor. For a.out and ecoff
830 formats (so far), this should result in considerable savings in time
831 and memory used while linking; slightly poorer performance than
832 before for formats not converted yet.
833
834 * Command-line parsing is no longer done with flex. This means
835 oddball characters in filenames won't get treated as argument
836 separators.
837
838 * HP-PA ELF support, by Jeff Law. (No SOM support yet.)
839
840 * Mach i386 support, by David Mackenzie.
841
842 * Irix 4 shared libraries are now supported (Irix 5 uses ELF, and ELF shared
843 libraries are not yet supported).
844
845 * COFF shared libraries (as on SCO) should work as well.
846
847 * The linker is disabled for Solaris. (Actually, it was in 2.3 also, I just
848 forgot to note it.) Some of their C library routines don't work when
849 statically linked, and the GNU linker doesn't support dynamic linking yet.
850
851 Changes in version 2.3:
852
853 * Weak symbols are now supported.
854
855 * ELF support has been added. The linker has been bootstrapped on
856 UnixWare and Solaris.
857
858 * Alpha OSF/1 support has been added (non dynamic linking only).
859
860 Changes in version 2.2:
861
862 * The `bfd' library has been updated to reduce a.out-format string
863 table size. The effect of this is that files linked from many input
864 files with duplicate symbols (`-g' debugging records, or identical
865 static symbols) should be much smaller.
866
867 Changes in version 2.1:
868
869 * The ld -ySYMBOL flag (to trace references to SYMBOL) is now implemented.
870
871 * There is now support for writing ECOFF files, so ld and the
872 other utilities should work on Risc/Ultrix and Irix.
873
874 \f
875 Copyright (C) 2012-2021 Free Software Foundation, Inc.
876
877 Copying and distribution of this file, with or without modification,
878 are permitted in any medium without royalty provided the copyright
879 notice and this notice are preserved.
880
881 Local variables:
882 fill-column: 79
883 End: