1-*- text -*-
2
3Changes in 2.28:
4
5* The EXCLUDE_FILE linker script construct can now be applied outside of the
6  section list in order for the exclusions to apply over all input sections in
7  the list.
8
9* Add support for the RISC-V architecture.
10
11* The command line option --no-eh-frame-hdr can now be used in ELF based
12  linkers to disable the automatic generation of .eh_frame_hdr sections.
13
14* Add --in-implib=<infile> to the ARM linker to enable specifying a set of
15  Secure Gateway veneers that must exist in the output import library specified
16  by --out-implib=<outfile> and the address they must have.  As such,
17  --in-implib is only supported in combination with --cmse-implib.
18
19* Extended the --out-implib=<file> option, previously restricted to x86 PE
20  targets, to any ELF based target.  This allows the generation of an import
21  library for an ELF executable, which can then be used by another application
22  to link against the executable.
23
24Changes in 2.27:
25
26* Add a configure option --enable-relro to decide whether -z relro should
27  be enabled in ELF linker by default.  Default to yes for all Linux
28  targets except FRV, HPPA, IA64 and MIPS.
29
30* Support for -z noreloc-overflow in the x86-64 ELF linker to disable
31  relocation overflow check.
32
33* Add -z common/-z nocommon options for ELF targets to control whether to
34  convert common symbols to the STT_COMMON type during a relocatable link.
35
36* Support for -z nodynamic-undefined-weak in the x86 ELF linker, which
37  avoids dynamic relocations against undefined weak symbols in executable.
38
39* The NOCROSSREFSTO command was added to the linker script language.
40
41* Add --no-apply-dynamic-relocs to the AArch64 linker to do not apply link-time
42  values for dynamic relocations.
43
44Changes in 2.26:
45
46* Add --fix-stm32l4xx-629360 to the ARM linker to enable a link-time
47  workaround for a bug in the bus matrix / memory controller for some of
48  the STM32 Cortex-M4 based products (STM32L4xx)
49
50* Add a configure option --enable-compressed-debug-sections={all,ld} to
51  decide whether DWARF debug sections should be compressed by default.
52
53* Add support for the ARC EM/HS, and ARC600/700 architectures.
54
55* Experimental support for linker garbage collection (--gc-sections)
56  has been enabled for COFF and PE based targets.
57
58* New command line option for ELF targets to compress DWARF debug
59  sections, --compress-debug-sections=[none|zlib|zlib-gnu|zlib-gabi].
60
61* New command line option, --orphan-handling=[place|warn|error|discard], to
62  adjust how orphan sections are handled.  The default is 'place' which gives
63  the current behaviour, 'warn' and 'error' issue a warning or error
64  respectively when orphan sections are found, and 'discard' will discard all
65  orphan sections.
66
67* Add support for LLVM plugin.
68
69* Add --print-memory-usage option to report memory blocks usage.
70
71* Add --require-defined option, it's like --undefined except the new symbol
72  must be defined by the end of the link.
73
74Changes in 2.25:
75
76* PE binaries now once again contain real timestamps by default.  To disable
77  the inclusion of a timestamp in a PE binary, use the --no-insert-timestamp
78  command line option.
79
80* Replace support for openrisc and or32 with support for or1k.
81
82* Add support for the --build-id command line option to COFF based targets.
83
84* x86/x86_64 pe-coff now supports the --build-id option.
85
86* Add support for the Andes NDS32.
87
88Changes in 2.24:
89
90* Add LOG2CEIL() builtin function to the linker script language
91
92* Add support for the Texas Instruments MSP430X processor.
93
94* Add support for Altera Nios II.
95
96* Add support for the V850E3V5 architecture.
97
98* Add support for the Imagination Technologies Meta processor.
99
100* --enable-new-dtags no longer generates old dtags in addition to new dtags.
101
102* Remove linker support for MIPS ECOFF targets.
103
104* Add ALIGN_WITH_INPUT to the linker script language to force the alignment of
105  an output section to use the maximum alignment of all its input sections.
106
107Changes in 2.23:
108
109* Enable compressed debug section feature for x86/x86_64 pe-coff.
110
111* Add support for the 64-bit ARM architecture: AArch64.
112
113* Added SORT_NONE to the linker script language to disable section sorting.
114
115* Add a linker-provided symbol when producing ELF output, '__ehdr_start'
116  to point to the ELF file header (and nearby program headers) in the
117  program's memory image.
118
119* Add support for S12X processor.
120
121* Add support for the VLE extension to the PowerPC architecture.
122
123* Add support for the Freescale XGATE architecture.
124
125* Add option -f FILE on AIX (for response file).
126
127* Add support for the Renesas RL78 architecture.
128
129* Add support for the Adapteva EPIPHANY architecture.
130
131Changes in 2.22:
132
133* --copy-dt-needed-entries is no longer enabled by default.  Instead
134  --no-copy-dt-needed-entries is the default.
135
136* INPUT_SECTION_FLAGS has been added to the linker script language
137  to allow selection of input sections by section header section flags.
138
139* Add support for the Tilera TILEPro and TILE-Gx architectures.
140
141* Added SORT_BY_INIT_PRIORITY to the linker script language to permit
142  sorting sections by numerical value of the GCC init_priority attribute
143  encoded in the section name.
144
145Changes in 2.21:
146
147* Linker script expression evaluation is somewhat more sane.  This may
148  break scripts that depend on quirks of the old expression evaluation.
149
150* Turn off underscoring for x86_64 PE+-COFF targets.  For old behavior the
151  option --enable-leading-mingw64-underscores can be used on configure of
152  bfd.
153
154* Add support for the TMS320C6000 (TI C6X) processor family.
155
156* --add-needed renamed to --copy-dt-needed-entries in order to avoid confusion
157  with --as-needed option.
158
159* Extend .def file syntax by '== <ID>' for imports and exports. This allows
160  to alias the import/export table name written in PE image.
161
162* Add --exclude-all-symbols option to PE based linkers.  This prevents all
163  symbols from automatically being exported.
164
165* Add support for the Renesas RX processor.
166
167* Add support for alpha-vms target.
168
169Changes in 2.20:
170
171* GNU/Linux targets now support the STB_GNU_UNIQUE symbol binding.  This is a
172  GNU extension to the standard set of ELF symbol bindings.  The binding will
173  be passed on to the dynamic linker which will make sure that in the entire
174  process there is just one symbol with the given name and type in use.
175
176* PE targets now support a GNU extension to allow the alignment of common
177  common symbols to be specified.  This support uses custom options in
178  the .drectve section, which will be disregarded by the native tools.
179
180* PE targets now add primitive support for ELF version scripts; symbols
181  are not versioned, but the local and global symbol visibility directives
182  are respected when filtering symbols in auto-export mode.
183
184* New option --no-export-dynamic to undo the effect of the -E and
185  --export-dynamic options.
186
187* ELF: --warn-alternate-em option to warn if an object has alternate
188  ELF machine code.
189
190* New script function REGION_ALIAS to add alias names to memory regions.
191
192* PE targets no longer make use of the long section names PE extension to
193  the COFF format when generating executable images, by default.  The old
194  (slightly non-conformant) behaviour can still be invoked by using the
195  new '--enable-long-section-names' command-line option.  It is also enabled
196  automatically in the presence of un-stripped debug information, as GDB
197  needs to be able to find the debug info sections by their full names.
198
199* For GNU/Linux systems the linker will now avoid processing any relocations
200  made against symbols of the STT_GNU_IFUNC type and instead emit them into
201  the resulting binary for processing by the loader.
202
203* --as-needed now links in a dynamic library if it satisfies undefined
204  symbols in regular objects, or in other dynamic libraries.  In the
205  latter case the library is not linked if it is found in a DT_NEEDED
206  entry of one of the libraries already linked.
207
208* Add a new command line option, -Ttext-segment ADDR, for ELF targets
209  to set the address of the first byte of the text segment.
210
211* Add support for Sunplus score architecture.
212
213* Add new option --use-nul-prefixed-import-tables to ld for PE targets to
214  allow fallback to old import table generation with null element prefix.
215
216* Windows PE systems now support a new --exclude-modules-for-implib option,
217  allowing users to partition object files and archive members between a DLL
218  and its associated import library as they are generated during linking.
219
220* Add support for Lattice Mico32 (lm32) architecture.
221
222* Add CR16 ELF --embedded-relocs (used to embedded relocations into binaries
223  for Embedded-PIC code) option.
224
225* Add to the PE/PE+ targets the support of two different kinds of
226  pseudo-relocations.  They can be selected by the switches
227  --enable-runtime-pseudo-reloc-v1 and --enable-runtime-pseudo-reloc-v2.
228  For the switch --enable-runtime-pseudo-reloc it uses for 32-bit
229  runtime pseudo relocation version one, for 64-bit the version two.
230
231Changes in 2.19:
232
233* Linker scripts support a new INSERT command that makes it easier to
234  augment the default script.
235
236* Linker script input section filespecs may now specify a file within an
237  archive by writing "archive:file".
238
239* The --sort-common switch now has an optional argument which specifies the
240  direction of sorting.
241
242* The M68K linker now supports multiple GOT generation schemes controlled via
243  the --got=<type> command line option.
244
245* The ARM EABI linker will now generate stubs for function calls to symbols
246  that are too far away.  The placement of the stubs is controlled by a new
247  linker command line option: --stub-group-size=N.
248
249Changes in 2.18:
250
251* Linker sources now released under version 3 of the GNU General Public
252  License.
253
254* ELF: New --build-id option to generate a unique per-binary identifier
255  embedded in a note section.
256
257* Added support for National Semicondutor CompactRISC (ie CR16) target.
258
259* -l:foo now searches the library path for a filename called foo,
260  without converting it to libfoo.a or libfoo.so.
261
262* Add a new command line option '--default-script=FILE' or '-dT FILE'
263  which specifies a replacement for the built in, default linker
264  script.
265
266* ELF: Add -Bsymbolic-functions, --dynamic-list-cpp-new, which puts C++
267  operator new and delete on the dynamic list, and --dynamic-list-data,
268  builtin list for --dynamic-list, which puts global data symbols on the
269  dynamic list.
270
271* Add support for x86_64 PE+ target.
272
273* Add support for Score target.
274
275* ELF: Add --dynamic-list option to specify a list of global symbols
276  whose references shouldn't be bound to the definition within the
277  shared library, or a list of symbols which should be added to the
278  symbol table in the executable.
279
280* The default output section LMA has changed for allocatable sections from
281  being equal to VMA, to keeping the difference between LMA and VMA the same as
282  the previous output section in the same region.  This is a more useful
283  default when using overlays and other cases where you specify an LMA
284  differing from the VMA for some sections.
285
286* New switch: --print-gc-sections to list any sections removed by garabge
287  collection.
288
289* ARM: Added --vfp11-denorm-fix option to work around an erratum in current
290  VFP11 coprocessors.
291
292Changes in 2.17:
293
294* Support for the Infineon XC16X has been added by KPIT Cummins Infosystems.
295
296* Modify the Linux linker search order to better match ld.so search order.
297  Look for DT_NEEDED libraries in paths specified by ld.so.conf before
298  searching the default directories, rather than vice versa.
299  Use $prefix/etc/ld.so.conf if it exists, otherwise /etc/ld.so.conf.
300
301* PE-COFF: Forward exports from DLL's can now be specified in .def files
302  passed directly to ld.
303
304* Support for the Z80 processor family has been added.
305
306* Add support for the "@<file>" syntax to the command line, so that extra
307  switches can be read from <file>.
308
309Changes in 2.16:
310
311* Support for the R_ARM_V4BX relocation as defined in the ARM AAELF
312  specification has been added via the --fix-v4bx command-line option.
313
314* New linker script construct AS_NEEDED(), which sets the --as-needed flag
315  for input files listed inside of it.
316
317* A new command-line option, --sysroot, can be used to override the
318  default sysroot location.  It only applies to toolchains that were
319  configured using --with-sysroot.
320
321* New linker script functions: ORIGIN() and LENGTH() which return information
322  about a specified memory region.
323
324* Port to MAXQ processor contributed by HCL Tech.
325
326* Added SEGMENT_START to the linker script language to permit the user to
327  override the base address for a segment from the command-line.
328
329* ELF: --warn-shared-textrel option to warn if adding a DT_TEXTREL to a shared
330  object.
331
332* Added SORT_BY_NAME and SORT_BY_ALIGNMENT to the linker script
333  language to permit sorting sections by section name or section
334  maximum alignment.
335
336* Added a new linker command line switch, --sort-section name|alignment,
337  to sort sections by section name or maximum alignment.
338
339* ELF: --add-needed/--no-add-needed options to control if a DT_NEEDED tag
340  should be added when a shared library comes from DT_NEEDED tags.
341
342* Support for the crx-elf target added.
343
344* Support for the sh-symbianelf target added.
345
346* A new linker command line switch has been added which allows the hash table
347  size to be set to a suitable prime value near to its argument.  This switch
348  is --hash-size=<NUMBER>.  Also if the switch --reduce-memory-overheads is
349  used, and --hash-size has not been used, then the default value will be set
350  to 1021.
351
352* Linker map files are now generated with an O(N) algorithm for finding symbols
353  that are defined in each section.  This uses about 40% more memory for
354  symbols than the old O(N^2) algorithm.  You can use the new
355  --reduce-memory-overheads option to select the old algorithm; this option
356  might also be used in the future to select similar tradeoffs.
357
358Changes in 2.15:
359
360* ELF: --as-needed/--no-as-needed options to control if a DT_NEEDED tag should
361  be added only when a shared library is referenced.
362
363* PE: --large-address-aware option to indicate executables support virtual
364  addresses greater than 2 gigabytes.
365
366* DWARF 2 support for i386pe added.
367
368* The linker script operator DEFINED() will now yield 1 only for a symbol that
369  is defined before the statement where DEFINED is used.
370
371* The MIPS --embedded-relocs (used to embed relocations into binaries for
372  Embedded-PIC code) is deprecated and will be removed in a future release.
373
374* cr16c support added by NSC.
375
376* m32r Linux (ELF) support added by Renesas.
377
378* Improved linker's handling of unresolved symbols.  The switch
379  --unresolved-symbols=<method> has been added to tell the linker when it
380  should report them and the switch --warn-unresolved-symbols has been added to
381  make reports be issued as warning messages rather than errors.
382
383Changes in 2.14:
384
385* Added support for Xtensa architecture.
386
387* Added --with-sysroot configure switch to specify a target system root, for
388  linking against a target filesystem image.
389
390* Added --accept-unknown-linker-format to restore old linker behaviour (pre
391  2.14) of silently accepting and linking in any files in an unknown binary
392  file format.
393
394* Added --no-omagic to undo the effects of the -N option.
395
396* Support for Texas Instruments TMS320C4x and TMS320C3x series of
397  DSP's contributed by Michael Hayes and Svein E. Seldal.
398
399* Added --with-lib-path configure switch to specify default value for
400  LIB_PATH.
401
402* ARM port to QNX operating system added by Graeme Peterson.
403
404* IP2K support added by Denis Chertykov.
405
406Changes in 2.13:
407
408* Support for the Fujitsu FRV architecture added by Red Hat. Models for FR400
409  and FR500 included.
410
411Changes in version 2.13:
412
413* DEC VAX ELF support, by Matt Thomas.
414
415Changes in version 2.12:
416
417* Support for Don Knuth's MMIX, by Hans-Peter Nilsson.
418
419* Support for the OpenRISC 32-bit embedded processor by OpenCores.
420
421* Support for -z nocopyreloc in the x86 ELF linker, which disables
422  production of copy relocs.  Warning: using this option may result in
423  non-sharable applications.
424
425* Support for -z combreloc in the ELF linker, which puts dynamic
426  relocations against the same symbol together, so that dynamic linker
427  can use an one-entry symbol lookup cache.
428
429* Support for ELF SHF_MERGE section merging, by Jakub Jelinek.
430
431Changes in version 2.11:
432
433* Support for AMD x86-64 architecture, by Jan Hubicka, SuSE Labs.
434
435* Support added for eliminating duplicate DWARF2 debug information by
436  having the compiler generate the information in sections called
437  .gnu.linkonce.wi.XXXX where XXXX is a checksum for the contents.  The
438  linker then merges these sections together into the normal .debug_info
439  section.
440
441* The native ELF linker now searches the directories in DT_RUNPATH or
442  DT_RPATH of a shared library for shared libraries needed by it.
443
444* TI C54x support, by Timothy Wall.
445
446* Added command line switch --section-start to set the start address of any
447  specified section.
448
449* Added ability to emit full relocation information in linked executables,
450  enabled by --emit-relocs.  Some post-linkage optimization tools need
451  this information in order to be able to correctly identify and perform
452  symbol relative addressing in the event of changes in section contents
453  (instructions being added or deleted, extending data sections, etc.)
454
455* Support for i860, by Jason Eckhardt (preliminary, alpha quality).
456
457* Support for CRIS (Axis Communications ETRAX series).
458
459* Support for PDP-11 and 2.11BSD a.out format, by Lars Brinkhoff.
460
461Changes in version 2.10:
462
463* Added AT> to the linker script language to allow load-time allocation of
464  sections into regions.
465
466* Added garbage collection of unused sections, enabled by --gc-sections.
467  It does require a bit of backend support; currently implemented are
468  arm-elf, avr-elf, d10v-elf, fr30-elf, i386-elf, m32r-elf, m68k-elf,
469  mcore-elf, mips-elf, mn10300-elf, ppc-elf, sh-elf, sparc-elf, and v850-elf.
470  Others will ignore the option.
471
472* Added SORT to the linker script language to permit sorting sections by file
473  name or section name.
474
475* Added EXTERN to the linker script language as an equivalent to the -u
476  command-line option.
477
478* Added ASSERT to the linker script language.
479
480* Added EXCLUDE_FILE to the linker script language for further control over
481  wildcard file names.
482
483* Added -O option to optimize linker output (as of this writing, this only
484  affects ELF shared library generation).
485
486* The -e option now accepts a number as well as a symbol name.
487
488* Added --no-undefined option to disallow undefined symbols when creating a
489  shared library.
490
491* The linker now issues a warning, not an error, for an undefined symbol when
492  using -Bsymbolic; use the new --no-undefined option to get the old
493  behaviour.
494
495* Added --demangle and --no-demangle options.
496
497Changes in version 2.9:
498
499* Added SQUAD to the linker script language.
500
501* New option --no-warn-mismatch.
502
503* The MEMORY command now parses the attributes to determine where sections that
504  are not placed in a specific memory region are placed.
505
506Changes in version 2.8:
507
508* Linker scripts may now contain shell wildcard characters for file and section
509  names.
510
511* The linker now supports symbol versions in ELF.
512
513* The NOCROSSREFS command was added to the linker script language.
514
515* The LOADADDR expression was added to the linker script language.
516
517* MAX and MIN functions were added to the linker script language.
518
519* The OVERLAY construct was added to the linker script language.
520
521* New option --warn-section-align to warn when the address of an output section
522  changes due to alignment of an input section.
523
524* New options --filter/-F and --auxiliary/-f.
525
526Changes in version 2.7:
527
528* New option --cref to print out a cross reference table.
529
530* New option --wrap SYMBOL.
531
532* New option --no-whole-archive, to turn off the effect of --whole-archive.
533
534* Input sections assigned to the output section /DISCARD/ in the linker script
535  are not included in the output file.
536
537* The SunOS and ELF linkers now merge stabs debugging information which uses
538  the N_BINCL and N_EINCL stab types.  This reduces the amount of debugging
539  information generated.
540
541Changes in version 2.6:
542
543* When an ELF section name is representable as a C identifier (this is not true
544of most ELF section names), the linker will automatically define symbols
545__start_SECNAME and __stop_SECNAME, where SECNAME is the section name, at the
546beginning and the end of the section.  This is used by glibc.
547
548  Addendum: Current versions of the linker (at least for version 2.18 onwards
549and possibly much earlier as well) place two restrictions on this feature:  The
550symbols are only implemented for orphaned sections, not for explicitly placed
551sections and they are PROVIDEd rather than being defined.
552
553* When an ELF section named .gnu.warning is encountered in an input file, the
554contents of the section are displayed as an error message, and the section is
555not copied into the output file.  This is used by glibc.
556
557* When an ELF section named .gnu.warning.SYMBOL is encountered in an input
558file, and the symbol SYMBOL is referenced by some object file, the contents of
559the section are displayed as an error message.  The section is not copied into
560the output file, unless doing a relocatable or shared link.  This is used by
561glibc.
562
563* New options -split-by-reloc and -split-by-file.
564
565* The linker now supports linking PIC compiled code on SPARC SunOS.  It can
566also create SPARC SunOS shared libraries, and, like the native SunOS linker,
567will do so whenever there is an undefined symbol in the link and neither the -e
568nor the -r option was used.
569
570* The -rpath option may be used on SunOS to set the list of directories to be
571searched at run time.  This overrides the default of building the list from the
572-L options.
573
574* The COFF linker now combines debugging information for structs, unions, and
575enums, so that even if the same type is defined in multiple input files it will
576only be defined once in the output file.  The --traditional-format switch will
577prevent this optimization.
578
579Changes in version 2.5:
580
581* The linker now supports linking against SunOS shared libraries.  It still can
582not link SunOS PIC (Position Independent Code) files, so it can not be used to
583generate shared libraries.
584
585* The linker now supports linking against ELF shared libraries for the i386
586(UnixWare) and SPARC (Solaris).  It can also link ELF PIC files, and can be
587used to generate shared libraries.  Shared library generation is not well
588tested; please report any problems encountered.  The linker is now enabled for
589Solaris again.
590
591* Eric Youngdale has contributed Linux support code, including linking against
592Linux a.out shared libraries.  The linker produces Linux QMAGIC binaries.
593
594* The ELF backend has been converted to the new linker code.  To use the new
595ELF linker, each particular target requires a relocation function.  So far,
596this function has been written for i386 (UnixWare), SPARC (Solaris) MIPS (Irix
5975), and HPPA ELF targets.
598
599* The -( (--start-group) and -) (--end-group) options have been added to
600support searching a group of archives as though they were a single archive.
601This can also be used in a linker script, as GROUP ( files ).
602
603* When a file is named on the command line, and the linker does not recognize
604it as an object file, the linker will now treat the file as a linker script
605file.  A linker script named in this way augments, but does not replace, the
606default linker script.
607
608* The -warn-once option was added.  It causes the linker to only warn once per
609undefined symbol, rather than once per reference.
610
611* The COFF backend has been converted to the new linker code.  As with ELF, to
612use the new linker, each particular target requires a relocation function.  So
613far, this function has been written for the i386, m68k, a29k and SH targets.
614
615* The -V flag was made a synonym for -v, for SVR4 compatibility.  The old -V
616behaviour is available via --verbose.
617
618Changes in version 2.4:
619
620* New linker code, by Steve Chamberlain and Ian Taylor.  For a.out and ecoff
621  formats (so far), this should result in considerable savings in time
622  and memory used while linking; slightly poorer performance than
623  before for formats not converted yet.
624
625* Command-line parsing is no longer done with flex.  This means
626  oddball characters in filenames won't get treated as argument
627  separators.
628
629* HP-PA ELF support, by Jeff Law.  (No SOM support yet.)
630
631* Mach i386 support, by David Mackenzie.
632
633* Irix 4 shared libraries are now supported (Irix 5 uses ELF, and ELF shared
634  libraries are not yet supported).
635
636* COFF shared libraries (as on SCO) should work as well.
637
638* The linker is disabled for Solaris.  (Actually, it was in 2.3 also, I just
639  forgot to note it.)  Some of their C library routines don't work when
640  statically linked, and the GNU linker doesn't support dynamic linking yet.
641
642Changes in version 2.3:
643
644* Weak symbols are now supported.
645
646* ELF support has been added.  The linker has been bootstrapped on
647  UnixWare and Solaris.
648
649* Alpha OSF/1 support has been added (non dynamic linking only).
650
651Changes in version 2.2:
652
653* The `bfd' library has been updated to reduce a.out-format string
654  table size.  The effect of this is that files linked from many input
655  files with duplicate symbols (`-g' debugging records, or identical
656  static symbols) should be much smaller.
657
658Changes in version 2.1:
659
660* The ld -ySYMBOL flag (to trace references to SYMBOL) is now implemented.
661
662* There is now support for writing ECOFF files, so ld and the
663  other utilities should work on Risc/Ultrix and Irix.
664
665
666Copyright (C) 2012-2017 Free Software Foundation, Inc.
667
668Copying and distribution of this file, with or without modification,
669are permitted in any medium without royalty provided the copyright
670notice and this notice are preserved.
671
672Local variables:
673fill-column: 79
674End:
675