ld/NEWS

   1 -*- text -*-
   2 * Add -z globalaudit command line option to force audit libraries to be run
   3   for every dynamic object loaded by an executable - provided that the loader
   4   supports this functionality.
   5
   6 * Tighten linker script grammar around file name specifiers to prevent the use
   7   of SORT_BY_ALIGNMENT and SORT_BY_INIT_PRIORITY on filenames.  These would
   8   previously be accepted but had no effect.
   9
  10 * The EXCLUDE_FILE directive can now be placed within any SORT_* directive
  11   within input section lists.
  12
  13 Changes in 2.29:
  14
  15 * Support for -z shstk in the x86 ELF linker to generate
  16   GNU_PROPERTY_X86_FEATURE_1_SHSTK in ELF GNU program properties.
  17
  18 * Add support for GNU_PROPERTY_X86_FEATURE_1_SHSTK in ELF GNU program
  19   properties in the x86 ELF linker.
  20
  21 * Add support for GNU_PROPERTY_X86_FEATURE_1_IBT in ELF GNU program
  22   properties in the x86 ELF linker.
  23
  24 * Support for -z ibtplt in the x86 ELF linker to generate IBT-enabled
  25   PLT.
  26
  27 * Support for -z ibt in the x86 ELF linker to generate IBT-enabled
  28   PLT as well as GNU_PROPERTY_X86_FEATURE_1_IBT in ELF GNU program
  29   properties.
  30
  31 * Add support for ELF SHF_GNU_MBIND and PT_GNU_MBIND_XXX.
  32
  33 * Add support for ELF GNU program properties.
  34
  35 * Add support for the Texas Instruments PRU processor.
  36
  37 * When configuring for arc*-*-linux* targets the default linker emulation will
  38   change if --with-cpu=nps400 is used at configure time.
  39
  40 * Improve assignment of LMAs to orphan sections in some edge cases where a
  41   mixture of both AT>LMA_REGION and AT(LMA) are used.
  42
  43 * Orphan sections placed after an empty section that has an AT(LMA) will now
  44   take an load memory address starting from LMA.
  45
  46 * Section groups can now be resolved (the group deleted and the group members
  47   placed like normal sections) at partial link time either using the new linker
  48   option --force-group-allocation or by placing FORCE_GROUP_ALLOCATION into the
  49   linker script.
  50
  51 Changes in 2.28:
  52
  53 * The EXCLUDE_FILE linker script construct can now be applied outside of the
  54   section list in order for the exclusions to apply over all input sections in
  55   the list.
  56
  57 * Add support for the RISC-V architecture.
  58
  59 * The command line option --no-eh-frame-hdr can now be used in ELF based
  60   linkers to disable the automatic generation of .eh_frame_hdr sections.
  61
  62 * Add --in-implib=<infile> to the ARM linker to enable specifying a set of
  63   Secure Gateway veneers that must exist in the output import library specified
  64   by --out-implib=<outfile> and the address they must have.  As such,
  65   --in-implib is only supported in combination with --cmse-implib.
  66
  67 * Extended the --out-implib=<file> option, previously restricted to x86 PE
  68   targets, to any ELF based target.  This allows the generation of an import
  69   library for an ELF executable, which can then be used by another application
  70   to link against the executable.
  71
  72 Changes in 2.27:
  73
  74 * Add a configure option --enable-relro to decide whether -z relro should
  75   be enabled in ELF linker by default.  Default to yes for all Linux
  76   targets except FRV, HPPA, IA64 and MIPS.  Note that -z relro can increase
  77   disk and memory size.
  78
  79 * Support for -z noreloc-overflow in the x86-64 ELF linker to disable
  80   relocation overflow check.
  81
  82 * Add -z common/-z nocommon options for ELF targets to control whether to
  83   convert common symbols to the STT_COMMON type during a relocatable link.
  84
  85 * Support for -z nodynamic-undefined-weak in the x86 ELF linker, which
  86   avoids dynamic relocations against undefined weak symbols in executable.
  87
  88 * The NOCROSSREFSTO command was added to the linker script language.
  89
  90 * Add --no-apply-dynamic-relocs to the AArch64 linker to do not apply link-time
  91   values for dynamic relocations.
  92
  93 Changes in 2.26:
  94
  95 * Add --fix-stm32l4xx-629360 to the ARM linker to enable a link-time
  96   workaround for a bug in the bus matrix / memory controller for some of
  97   the STM32 Cortex-M4 based products (STM32L4xx)
  98
  99 * Add a configure option --enable-compressed-debug-sections={all,ld} to
 100   decide whether DWARF debug sections should be compressed by default.
 101
 102 * Add support for the ARC EM/HS, and ARC600/700 architectures.
 103
 104 * Experimental support for linker garbage collection (--gc-sections)
 105   has been enabled for COFF and PE based targets.
 106
 107 * New command line option for ELF targets to compress DWARF debug
 108   sections, --compress-debug-sections=[none|zlib|zlib-gnu|zlib-gabi].
 109
 110 * New command line option, --orphan-handling=[place|warn|error|discard], to
 111   adjust how orphan sections are handled.  The default is 'place' which gives
 112   the current behaviour, 'warn' and 'error' issue a warning or error
 113   respectively when orphan sections are found, and 'discard' will discard all
 114   orphan sections.
 115
 116 * Add support for LLVM plugin.
 117
 118 * Add --print-memory-usage option to report memory blocks usage.
 119
 120 * Add --require-defined option, it's like --undefined except the new symbol
 121   must be defined by the end of the link.
 122
 123 Changes in 2.25:
 124
 125 * PE binaries now once again contain real timestamps by default.  To disable
 126   the inclusion of a timestamp in a PE binary, use the --no-insert-timestamp
 127   command line option.
 128
 129 * Replace support for openrisc and or32 with support for or1k.
 130
 131 * Add support for the --build-id command line option to COFF based targets.
 132
 133 * x86/x86_64 pe-coff now supports the --build-id option.
 134
 135 * Add support for the Andes NDS32.
 136
 137 Changes in 2.24:
 138
 139 * Add LOG2CEIL() builtin function to the linker script language
 140
 141 * Add support for the Texas Instruments MSP430X processor.
 142
 143 * Add support for Altera Nios II.
 144
 145 * Add support for the V850E3V5 architecture.
 146
 147 * Add support for the Imagination Technologies Meta processor.
 148
 149 * --enable-new-dtags no longer generates old dtags in addition to new dtags.
 150
 151 * Remove linker support for MIPS ECOFF targets.
 152
 153 * Add ALIGN_WITH_INPUT to the linker script language to force the alignment of
 154   an output section to use the maximum alignment of all its input sections.
 155
 156 Changes in 2.23:
 157
 158 * Enable compressed debug section feature for x86/x86_64 pe-coff.
 159
 160 * Add support for the 64-bit ARM architecture: AArch64.
 161
 162 * Added SORT_NONE to the linker script language to disable section sorting.
 163
 164 * Add a linker-provided symbol when producing ELF output, '__ehdr_start'
 165   to point to the ELF file header (and nearby program headers) in the
 166   program's memory image.
 167
 168 * Add support for S12X processor.
 169
 170 * Add support for the VLE extension to the PowerPC architecture.
 171
 172 * Add support for the Freescale XGATE architecture.
 173
 174 * Add option -f FILE on AIX (for response file).
 175
 176 * Add support for the Renesas RL78 architecture.
 177
 178 * Add support for the Adapteva EPIPHANY architecture.
 179
 180 Changes in 2.22:
 181
 182 * --copy-dt-needed-entries is no longer enabled by default.  Instead
 183   --no-copy-dt-needed-entries is the default.
 184
 185 * INPUT_SECTION_FLAGS has been added to the linker script language
 186   to allow selection of input sections by section header section flags.
 187
 188 * Add support for the Tilera TILEPro and TILE-Gx architectures.
 189
 190 * Added SORT_BY_INIT_PRIORITY to the linker script language to permit
 191   sorting sections by numerical value of the GCC init_priority attribute
 192   encoded in the section name.
 193
 194 Changes in 2.21:
 195
 196 * Linker script expression evaluation is somewhat more sane.  This may
 197   break scripts that depend on quirks of the old expression evaluation.
 198
 199 * Turn off underscoring for x86_64 PE+-COFF targets.  For old behavior the
 200   option --enable-leading-mingw64-underscores can be used on configure of
 201   bfd.
 202
 203 * Add support for the TMS320C6000 (TI C6X) processor family.
 204
 205 * --add-needed renamed to --copy-dt-needed-entries in order to avoid confusion
 206   with --as-needed option.
 207
 208 * Extend .def file syntax by '== <ID>' for imports and exports. This allows
 209   to alias the import/export table name written in PE image.
 210
 211 * Add --exclude-all-symbols option to PE based linkers.  This prevents all
 212   symbols from automatically being exported.
 213
 214 * Add support for the Renesas RX processor.
 215
 216 * Add support for alpha-vms target.
 217
 218 Changes in 2.20:
 219
 220 * GNU/Linux targets now support the STB_GNU_UNIQUE symbol binding.  This is a
 221   GNU extension to the standard set of ELF symbol bindings.  The binding will
 222   be passed on to the dynamic linker which will make sure that in the entire
 223   process there is just one symbol with the given name and type in use.
 224
 225 * PE targets now support a GNU extension to allow the alignment of common
 226   common symbols to be specified.  This support uses custom options in
 227   the .drectve section, which will be disregarded by the native tools.
 228
 229 * PE targets now add primitive support for ELF version scripts; symbols
 230   are not versioned, but the local and global symbol visibility directives
 231   are respected when filtering symbols in auto-export mode.
 232
 233 * New option --no-export-dynamic to undo the effect of the -E and
 234   --export-dynamic options.
 235
 236 * ELF: --warn-alternate-em option to warn if an object has alternate
 237   ELF machine code.
 238
 239 * New script function REGION_ALIAS to add alias names to memory regions.
 240
 241 * PE targets no longer make use of the long section names PE extension to
 242   the COFF format when generating executable images, by default.  The old
 243   (slightly non-conformant) behaviour can still be invoked by using the
 244   new '--enable-long-section-names' command-line option.  It is also enabled
 245   automatically in the presence of un-stripped debug information, as GDB
 246   needs to be able to find the debug info sections by their full names.
 247
 248 * For GNU/Linux systems the linker will now avoid processing any relocations
 249   made against symbols of the STT_GNU_IFUNC type and instead emit them into
 250   the resulting binary for processing by the loader.
 251
 252 * --as-needed now links in a dynamic library if it satisfies undefined
 253   symbols in regular objects, or in other dynamic libraries.  In the
 254   latter case the library is not linked if it is found in a DT_NEEDED
 255   entry of one of the libraries already linked.
 256
 257 * Add a new command line option, -Ttext-segment ADDR, for ELF targets
 258   to set the address of the first byte of the text segment.
 259
 260 * Add support for Sunplus score architecture.
 261
 262 * Add new option --use-nul-prefixed-import-tables to ld for PE targets to
 263   allow fallback to old import table generation with null element prefix.
 264
 265 * Windows PE systems now support a new --exclude-modules-for-implib option,
 266   allowing users to partition object files and archive members between a DLL
 267   and its associated import library as they are generated during linking.
 268
 269 * Add support for Lattice Mico32 (lm32) architecture.
 270
 271 * Add CR16 ELF --embedded-relocs (used to embedded relocations into binaries
 272   for Embedded-PIC code) option.
 273
 274 * Add to the PE/PE+ targets the support of two different kinds of
 275   pseudo-relocations.  They can be selected by the switches
 276   --enable-runtime-pseudo-reloc-v1 and --enable-runtime-pseudo-reloc-v2.
 277   For the switch --enable-runtime-pseudo-reloc it uses for 32-bit
 278   runtime pseudo relocation version one, for 64-bit the version two.
 279
 280 Changes in 2.19:
 281
 282 * Linker scripts support a new INSERT command that makes it easier to
 283   augment the default script.
 284
 285 * Linker script input section filespecs may now specify a file within an
 286   archive by writing "archive:file".
 287
 288 * The --sort-common switch now has an optional argument which specifies the
 289   direction of sorting.
 290
 291 * The M68K linker now supports multiple GOT generation schemes controlled via
 292   the --got=<type> command line option.
 293
 294 * The ARM EABI linker will now generate stubs for function calls to symbols
 295   that are too far away.  The placement of the stubs is controlled by a new
 296   linker command line option: --stub-group-size=N.
 297
 298 Changes in 2.18:
 299
 300 * Linker sources now released under version 3 of the GNU General Public
 301   License.
 302
 303 * ELF: New --build-id option to generate a unique per-binary identifier
 304   embedded in a note section.
 305
 306 * Added support for National Semicondutor CompactRISC (ie CR16) target.
 307
 308 * -l:foo now searches the library path for a filename called foo,
 309   without converting it to libfoo.a or libfoo.so.
 310
 311 * Add a new command line option '--default-script=FILE' or '-dT FILE'
 312   which specifies a replacement for the built in, default linker
 313   script.
 314
 315 * ELF: Add -Bsymbolic-functions, --dynamic-list-cpp-new, which puts C++
 316   operator new and delete on the dynamic list, and --dynamic-list-data,
 317   builtin list for --dynamic-list, which puts global data symbols on the
 318   dynamic list.
 319
 320 * Add support for x86_64 PE+ target.
 321
 322 * Add support for Score target.
 323
 324 * ELF: Add --dynamic-list option to specify a list of global symbols
 325   whose references shouldn't be bound to the definition within the
 326   shared library, or a list of symbols which should be added to the
 327   symbol table in the executable.
 328
 329 * The default output section LMA has changed for allocatable sections from
 330   being equal to VMA, to keeping the difference between LMA and VMA the same as
 331   the previous output section in the same region.  This is a more useful
 332   default when using overlays and other cases where you specify an LMA
 333   differing from the VMA for some sections.
 334
 335 * New switch: --print-gc-sections to list any sections removed by garabge
 336   collection.
 337
 338 * ARM: Added --vfp11-denorm-fix option to work around an erratum in current
 339   VFP11 coprocessors.
 340
 341 Changes in 2.17:
 342
 343 * Support for the Infineon XC16X has been added by KPIT Cummins Infosystems.
 344
 345 * Modify the Linux linker search order to better match ld.so search order.
 346   Look for DT_NEEDED libraries in paths specified by ld.so.conf before
 347   searching the default directories, rather than vice versa.
 348   Use $prefix/etc/ld.so.conf if it exists, otherwise /etc/ld.so.conf.
 349
 350 * PE-COFF: Forward exports from DLL's can now be specified in .def files
 351   passed directly to ld.
 352
 353 * Support for the Z80 processor family has been added.
 354
 355 * Add support for the "@<file>" syntax to the command line, so that extra
 356   switches can be read from <file>.
 357
 358 Changes in 2.16:
 359
 360 * Support for the R_ARM_V4BX relocation as defined in the ARM AAELF
 361   specification has been added via the --fix-v4bx command-line option.
 362
 363 * New linker script construct AS_NEEDED(), which sets the --as-needed flag
 364   for input files listed inside of it.
 365
 366 * A new command-line option, --sysroot, can be used to override the
 367   default sysroot location.  It only applies to toolchains that were
 368   configured using --with-sysroot.
 369
 370 * New linker script functions: ORIGIN() and LENGTH() which return information
 371   about a specified memory region.
 372
 373 * Port to MAXQ processor contributed by HCL Tech.
 374
 375 * Added SEGMENT_START to the linker script language to permit the user to
 376   override the base address for a segment from the command-line.
 377
 378 * ELF: --warn-shared-textrel option to warn if adding a DT_TEXTREL to a shared
 379   object.
 380
 381 * Added SORT_BY_NAME and SORT_BY_ALIGNMENT to the linker script
 382   language to permit sorting sections by section name or section
 383   maximum alignment.
 384
 385 * Added a new linker command line switch, --sort-section name|alignment,
 386   to sort sections by section name or maximum alignment.
 387
 388 * ELF: --add-needed/--no-add-needed options to control if a DT_NEEDED tag
 389   should be added when a shared library comes from DT_NEEDED tags.
 390
 391 * Support for the crx-elf target added.
 392
 393 * Support for the sh-symbianelf target added.
 394
 395 * A new linker command line switch has been added which allows the hash table
 396   size to be set to a suitable prime value near to its argument.  This switch
 397   is --hash-size=<NUMBER>.  Also if the switch --reduce-memory-overheads is
 398   used, and --hash-size has not been used, then the default value will be set
 399   to 1021.
 400
 401 * Linker map files are now generated with an O(N) algorithm for finding symbols
 402   that are defined in each section.  This uses about 40% more memory for
 403   symbols than the old O(N^2) algorithm.  You can use the new
 404   --reduce-memory-overheads option to select the old algorithm; this option
 405   might also be used in the future to select similar tradeoffs.
 406
 407 Changes in 2.15:
 408
 409 * ELF: --as-needed/--no-as-needed options to control if a DT_NEEDED tag should
 410   be added only when a shared library is referenced.
 411
 412 * PE: --large-address-aware option to indicate executables support virtual
 413   addresses greater than 2 gigabytes.
 414
 415 * DWARF 2 support for i386pe added.
 416
 417 * The linker script operator DEFINED() will now yield 1 only for a symbol that
 418   is defined before the statement where DEFINED is used.
 419
 420 * The MIPS --embedded-relocs (used to embed relocations into binaries for
 421   Embedded-PIC code) is deprecated and will be removed in a future release.
 422
 423 * cr16c support added by NSC.
 424
 425 * m32r Linux (ELF) support added by Renesas.
 426
 427 * Improved linker's handling of unresolved symbols.  The switch
 428   --unresolved-symbols=<method> has been added to tell the linker when it
 429   should report them and the switch --warn-unresolved-symbols has been added to
 430   make reports be issued as warning messages rather than errors.
 431
 432 Changes in 2.14:
 433
 434 * Added support for Xtensa architecture.
 435
 436 * Added --with-sysroot configure switch to specify a target system root, for
 437   linking against a target filesystem image.
 438
 439 * Added --accept-unknown-linker-format to restore old linker behaviour (pre
 440   2.14) of silently accepting and linking in any files in an unknown binary
 441   file format.
 442
 443 * Added --no-omagic to undo the effects of the -N option.
 444
 445 * Support for Texas Instruments TMS320C4x and TMS320C3x series of
 446   DSP's contributed by Michael Hayes and Svein E. Seldal.
 447
 448 * Added --with-lib-path configure switch to specify default value for
 449   LIB_PATH.
 450
 451 * ARM port to QNX operating system added by Graeme Peterson.
 452
 453 * IP2K support added by Denis Chertykov.
 454
 455 Changes in 2.13:
 456
 457 * Support for the Fujitsu FRV architecture added by Red Hat. Models for FR400
 458   and FR500 included.
 459
 460 Changes in version 2.13:
 461
 462 * DEC VAX ELF support, by Matt Thomas.
 463
 464 Changes in version 2.12:
 465
 466 * Support for Don Knuth's MMIX, by Hans-Peter Nilsson.
 467
 468 * Support for the OpenRISC 32-bit embedded processor by OpenCores.
 469
 470 * Support for -z nocopyreloc in the x86 ELF linker, which disables
 471   production of copy relocs.  Warning: using this option may result in
 472   non-sharable applications.
 473
 474 * Support for -z combreloc in the ELF linker, which puts dynamic
 475   relocations against the same symbol together, so that dynamic linker
 476   can use an one-entry symbol lookup cache.
 477
 478 * Support for ELF SHF_MERGE section merging, by Jakub Jelinek.
 479
 480 Changes in version 2.11:
 481
 482 * Support for AMD x86-64 architecture, by Jan Hubicka, SuSE Labs.
 483
 484 * Support added for eliminating duplicate DWARF2 debug information by
 485   having the compiler generate the information in sections called
 486   .gnu.linkonce.wi.XXXX where XXXX is a checksum for the contents.  The
 487   linker then merges these sections together into the normal .debug_info
 488   section.
 489
 490 * The native ELF linker now searches the directories in DT_RUNPATH or
 491   DT_RPATH of a shared library for shared libraries needed by it.
 492
 493 * TI C54x support, by Timothy Wall.
 494
 495 * Added command line switch --section-start to set the start address of any
 496   specified section.
 497
 498 * Added ability to emit full relocation information in linked executables,
 499   enabled by --emit-relocs.  Some post-linkage optimization tools need
 500   this information in order to be able to correctly identify and perform
 501   symbol relative addressing in the event of changes in section contents
 502   (instructions being added or deleted, extending data sections, etc.)
 503
 504 * Support for i860, by Jason Eckhardt (preliminary, alpha quality).
 505
 506 * Support for CRIS (Axis Communications ETRAX series).
 507
 508 * Support for PDP-11 and 2.11BSD a.out format, by Lars Brinkhoff.
 509
 510 Changes in version 2.10:
 511
 512 * Added AT> to the linker script language to allow load-time allocation of
 513   sections into regions.
 514
 515 * Added garbage collection of unused sections, enabled by --gc-sections.
 516   It does require a bit of backend support; currently implemented are
 517   arm-elf, avr-elf, d10v-elf, fr30-elf, i386-elf, m32r-elf, m68k-elf,
 518   mcore-elf, mips-elf, mn10300-elf, ppc-elf, sh-elf, sparc-elf, and v850-elf.
 519   Others will ignore the option.
 520
 521 * Added SORT to the linker script language to permit sorting sections by file
 522   name or section name.
 523
 524 * Added EXTERN to the linker script language as an equivalent to the -u
 525   command-line option.
 526
 527 * Added ASSERT to the linker script language.
 528
 529 * Added EXCLUDE_FILE to the linker script language for further control over
 530   wildcard file names.
 531
 532 * Added -O option to optimize linker output (as of this writing, this only
 533   affects ELF shared library generation).
 534
 535 * The -e option now accepts a number as well as a symbol name.
 536
 537 * Added --no-undefined option to disallow undefined symbols when creating a
 538   shared library.
 539
 540 * The linker now issues a warning, not an error, for an undefined symbol when
 541   using -Bsymbolic; use the new --no-undefined option to get the old
 542   behaviour.
 543
 544 * Added --demangle and --no-demangle options.
 545
 546 Changes in version 2.9:
 547
 548 * Added SQUAD to the linker script language.
 549
 550 * New option --no-warn-mismatch.
 551
 552 * The MEMORY command now parses the attributes to determine where sections that
 553   are not placed in a specific memory region are placed.
 554
 555 Changes in version 2.8:
 556
 557 * Linker scripts may now contain shell wildcard characters for file and section
 558   names.
 559
 560 * The linker now supports symbol versions in ELF.
 561
 562 * The NOCROSSREFS command was added to the linker script language.
 563
 564 * The LOADADDR expression was added to the linker script language.
 565
 566 * MAX and MIN functions were added to the linker script language.
 567
 568 * The OVERLAY construct was added to the linker script language.
 569
 570 * New option --warn-section-align to warn when the address of an output section
 571   changes due to alignment of an input section.
 572
 573 * New options --filter/-F and --auxiliary/-f.
 574
 575 Changes in version 2.7:
 576
 577 * New option --cref to print out a cross reference table.
 578
 579 * New option --wrap SYMBOL.
 580
 581 * New option --no-whole-archive, to turn off the effect of --whole-archive.
 582
 583 * Input sections assigned to the output section /DISCARD/ in the linker script
 584   are not included in the output file.
 585
 586 * The SunOS and ELF linkers now merge stabs debugging information which uses
 587   the N_BINCL and N_EINCL stab types.  This reduces the amount of debugging
 588   information generated.
 589
 590 Changes in version 2.6:
 591
 592 * When an ELF section name is representable as a C identifier (this is not true
 593 of most ELF section names), the linker will automatically define symbols
 594 __start_SECNAME and __stop_SECNAME, where SECNAME is the section name, at the
 595 beginning and the end of the section.  This is used by glibc.
 596
 597   Addendum: Current versions of the linker (at least for version 2.18 onwards
 598 and possibly much earlier as well) place two restrictions on this feature:  The
 599 symbols are only implemented for orphaned sections, not for explicitly placed
 600 sections and they are PROVIDEd rather than being defined.
 601
 602 * When an ELF section named .gnu.warning is encountered in an input file, the
 603 contents of the section are displayed as an error message, and the section is
 604 not copied into the output file.  This is used by glibc.
 605
 606 * When an ELF section named .gnu.warning.SYMBOL is encountered in an input
 607 file, and the symbol SYMBOL is referenced by some object file, the contents of
 608 the section are displayed as an error message.  The section is not copied into
 609 the output file, unless doing a relocatable or shared link.  This is used by
 610 glibc.
 611
 612 * New options -split-by-reloc and -split-by-file.
 613
 614 * The linker now supports linking PIC compiled code on SPARC SunOS.  It can
 615 also create SPARC SunOS shared libraries, and, like the native SunOS linker,
 616 will do so whenever there is an undefined symbol in the link and neither the -e
 617 nor the -r option was used.
 618
 619 * The -rpath option may be used on SunOS to set the list of directories to be
 620 searched at run time.  This overrides the default of building the list from the
 621 -L options.
 622
 623 * The COFF linker now combines debugging information for structs, unions, and
 624 enums, so that even if the same type is defined in multiple input files it will
 625 only be defined once in the output file.  The --traditional-format switch will
 626 prevent this optimization.
 627
 628 Changes in version 2.5:
 629
 630 * The linker now supports linking against SunOS shared libraries.  It still can
 631 not link SunOS PIC (Position Independent Code) files, so it can not be used to
 632 generate shared libraries.
 633
 634 * The linker now supports linking against ELF shared libraries for the i386
 635 (UnixWare) and SPARC (Solaris).  It can also link ELF PIC files, and can be
 636 used to generate shared libraries.  Shared library generation is not well
 637 tested; please report any problems encountered.  The linker is now enabled for
 638 Solaris again.
 639
 640 * Eric Youngdale has contributed Linux support code, including linking against
 641 Linux a.out shared libraries.  The linker produces Linux QMAGIC binaries.
 642
 643 * The ELF backend has been converted to the new linker code.  To use the new
 644 ELF linker, each particular target requires a relocation function.  So far,
 645 this function has been written for i386 (UnixWare), SPARC (Solaris) MIPS (Irix
 646 5), and HPPA ELF targets.
 647
 648 * The -( (--start-group) and -) (--end-group) options have been added to
 649 support searching a group of archives as though they were a single archive.
 650 This can also be used in a linker script, as GROUP ( files ).
 651
 652 * When a file is named on the command line, and the linker does not recognize
 653 it as an object file, the linker will now treat the file as a linker script
 654 file.  A linker script named in this way augments, but does not replace, the
 655 default linker script.
 656
 657 * The -warn-once option was added.  It causes the linker to only warn once per
 658 undefined symbol, rather than once per reference.
 659
 660 * The COFF backend has been converted to the new linker code.  As with ELF, to
 661 use the new linker, each particular target requires a relocation function.  So
 662 far, this function has been written for the i386, m68k, a29k and SH targets.
 663
 664 * The -V flag was made a synonym for -v, for SVR4 compatibility.  The old -V
 665 behaviour is available via --verbose.
 666
 667 Changes in version 2.4:
 668
 669 * New linker code, by Steve Chamberlain and Ian Taylor.  For a.out and ecoff
 670   formats (so far), this should result in considerable savings in time
 671   and memory used while linking; slightly poorer performance than
 672   before for formats not converted yet.
 673
 674 * Command-line parsing is no longer done with flex.  This means
 675   oddball characters in filenames won't get treated as argument
 676   separators.
 677
 678 * HP-PA ELF support, by Jeff Law.  (No SOM support yet.)
 679
 680 * Mach i386 support, by David Mackenzie.
 681
 682 * Irix 4 shared libraries are now supported (Irix 5 uses ELF, and ELF shared
 683   libraries are not yet supported).
 684
 685 * COFF shared libraries (as on SCO) should work as well.
 686
 687 * The linker is disabled for Solaris.  (Actually, it was in 2.3 also, I just
 688   forgot to note it.)  Some of their C library routines don't work when
 689   statically linked, and the GNU linker doesn't support dynamic linking yet.
 690
 691 Changes in version 2.3:
 692
 693 * Weak symbols are now supported.
 694
 695 * ELF support has been added.  The linker has been bootstrapped on
 696   UnixWare and Solaris.
 697
 698 * Alpha OSF/1 support has been added (non dynamic linking only).
 699
 700 Changes in version 2.2:
 701
 702 * The `bfd' library has been updated to reduce a.out-format string
 703   table size.  The effect of this is that files linked from many input
 704   files with duplicate symbols (`-g' debugging records, or identical
 705   static symbols) should be much smaller.
 706
 707 Changes in version 2.1:
 708
 709 * The ld -ySYMBOL flag (to trace references to SYMBOL) is now implemented.
 710
 711 * There is now support for writing ECOFF files, so ld and the
 712   other utilities should work on Risc/Ultrix and Irix.
 713
 714 \f
 715 Copyright (C) 2012-2018 Free Software Foundation, Inc.
 716
 717 Copying and distribution of this file, with or without modification,
 718 are permitted in any medium without royalty provided the copyright
 719 notice and this notice are preserved.
 720
 721 Local variables:
 722 fill-column: 79
 723 End: