ld/NEWS

   1 -*- text -*-
   2
   3 Changes in 2.33:
   4
   5 * Add target handlers for AArch64 for ELF GNU program properties.
   6
   7 * Add support for GNU_PROPERTY_AARCH64_FEATURE_1_BTI in ELF GNU program
   8   properties in the AArch64 ELF linker.
   9
  10 * Add support for GNU_PROPERTY_AARCH64_FEATURE_1_PAC in ELF GNU program
  11   properties in the AArch64 ELF linker.
  12
  13 Changes in 2.32:
  14
  15 * Report property change in linker map file when merging GNU properties.
  16
  17 * Add support for the C-SKY processor series.
  18
  19 * -t now doesn't report members within archives, unless -t is given twice.
  20   A single -t is now more useful when generating a list of files that should be
  21   packaged for a linker bug report.  For example:
  22     gcc hello.c -save-temps -Wl,-t | xargs realpath | sort | uniq > files
  23     tar cJf test.tar.xz `cat files`
  24
  25 Changes in 2.31:
  26
  27 * Speed up direct linking with DLLs for Cygwin and Mingw targets.
  28
  29 * Add a configure option --enable-separate-code to decide whether
  30   -z separate-code should be enabled in ELF linker by default.  Default
  31   to yes for Linux/x86 targets.  Note that -z separate-code can increase
  32   disk and memory size.
  33
  34 Changes in 2.30:
  35
  36 * Add -z separate-code to generate separate code PT_LOAD segment.
  37
  38 * Add "-z undefs" command-line option as the inverse of the "-z defs" option.
  39
  40 * Add -z globalaudit command-line option to force audit libraries to be run
  41   for every dynamic object loaded by an executable - provided that the loader
  42   supports this functionality.
  43
  44 * Tighten linker script grammar around file name specifiers to prevent the use
  45   of SORT_BY_ALIGNMENT and SORT_BY_INIT_PRIORITY on filenames.  These would
  46   previously be accepted but had no effect.
  47
  48 * The EXCLUDE_FILE directive can now be placed within any SORT_* directive
  49   within input section lists.
  50
  51 Changes in 2.29:
  52
  53 * Support for -z shstk in the x86 ELF linker to generate
  54   GNU_PROPERTY_X86_FEATURE_1_SHSTK in ELF GNU program properties.
  55
  56 * Add support for GNU_PROPERTY_X86_FEATURE_1_SHSTK in ELF GNU program
  57   properties in the x86 ELF linker.
  58
  59 * Add support for GNU_PROPERTY_X86_FEATURE_1_IBT in ELF GNU program
  60   properties in the x86 ELF linker.
  61
  62 * Support for -z ibtplt in the x86 ELF linker to generate IBT-enabled
  63   PLT.
  64
  65 * Support for -z ibt in the x86 ELF linker to generate IBT-enabled
  66   PLT as well as GNU_PROPERTY_X86_FEATURE_1_IBT in ELF GNU program
  67   properties.
  68
  69 * Add support for ELF SHF_GNU_MBIND and PT_GNU_MBIND_XXX.
  70
  71 * Add support for ELF GNU program properties.
  72
  73 * Add support for the Texas Instruments PRU processor.
  74
  75 * When configuring for arc*-*-linux* targets the default linker emulation will
  76   change if --with-cpu=nps400 is used at configure time.
  77
  78 * Improve assignment of LMAs to orphan sections in some edge cases where a
  79   mixture of both AT>LMA_REGION and AT(LMA) are used.
  80
  81 * Orphan sections placed after an empty section that has an AT(LMA) will now
  82   take an load memory address starting from LMA.
  83
  84 * Section groups can now be resolved (the group deleted and the group members
  85   placed like normal sections) at partial link time either using the new linker
  86   option --force-group-allocation or by placing FORCE_GROUP_ALLOCATION into the
  87   linker script.
  88
  89 Changes in 2.28:
  90
  91 * The EXCLUDE_FILE linker script construct can now be applied outside of the
  92   section list in order for the exclusions to apply over all input sections in
  93   the list.
  94
  95 * Add support for the RISC-V architecture.
  96
  97 * The command-line option --no-eh-frame-hdr can now be used in ELF based
  98   linkers to disable the automatic generation of .eh_frame_hdr sections.
  99
 100 * Add --in-implib=<infile> to the ARM linker to enable specifying a set of
 101   Secure Gateway veneers that must exist in the output import library specified
 102   by --out-implib=<outfile> and the address they must have.  As such,
 103   --in-implib is only supported in combination with --cmse-implib.
 104
 105 * Extended the --out-implib=<file> option, previously restricted to x86 PE
 106   targets, to any ELF based target.  This allows the generation of an import
 107   library for an ELF executable, which can then be used by another application
 108   to link against the executable.
 109
 110 Changes in 2.27:
 111
 112 * Add a configure option --enable-relro to decide whether -z relro should
 113   be enabled in ELF linker by default.  Default to yes for all Linux
 114   targets except FRV, HPPA, IA64 and MIPS.  Note that -z relro can increase
 115   disk and memory size.
 116
 117 * Support for -z noreloc-overflow in the x86-64 ELF linker to disable
 118   relocation overflow check.
 119
 120 * Add -z common/-z nocommon options for ELF targets to control whether to
 121   convert common symbols to the STT_COMMON type during a relocatable link.
 122
 123 * Support for -z nodynamic-undefined-weak in the x86 ELF linker, which
 124   avoids dynamic relocations against undefined weak symbols in executable.
 125
 126 * The NOCROSSREFSTO command was added to the linker script language.
 127
 128 * Add --no-apply-dynamic-relocs to the AArch64 linker to do not apply link-time
 129   values for dynamic relocations.
 130
 131 Changes in 2.26:
 132
 133 * Add --fix-stm32l4xx-629360 to the ARM linker to enable a link-time
 134   workaround for a bug in the bus matrix / memory controller for some of
 135   the STM32 Cortex-M4 based products (STM32L4xx)
 136
 137 * Add a configure option --enable-compressed-debug-sections={all,ld} to
 138   decide whether DWARF debug sections should be compressed by default.
 139
 140 * Add support for the ARC EM/HS, and ARC600/700 architectures.
 141
 142 * Experimental support for linker garbage collection (--gc-sections)
 143   has been enabled for COFF and PE based targets.
 144
 145 * New command-line option for ELF targets to compress DWARF debug
 146   sections, --compress-debug-sections=[none|zlib|zlib-gnu|zlib-gabi].
 147
 148 * New command-line option, --orphan-handling=[place|warn|error|discard], to
 149   adjust how orphan sections are handled.  The default is 'place' which gives
 150   the current behaviour, 'warn' and 'error' issue a warning or error
 151   respectively when orphan sections are found, and 'discard' will discard all
 152   orphan sections.
 153
 154 * Add support for LLVM plugin.
 155
 156 * Add --print-memory-usage option to report memory blocks usage.
 157
 158 * Add --require-defined option, it's like --undefined except the new symbol
 159   must be defined by the end of the link.
 160
 161 Changes in 2.25:
 162
 163 * PE binaries now once again contain real timestamps by default.  To disable
 164   the inclusion of a timestamp in a PE binary, use the --no-insert-timestamp
 165   command-line option.
 166
 167 * Replace support for openrisc and or32 with support for or1k.
 168
 169 * Add support for the --build-id command-line option to COFF based targets.
 170
 171 * x86/x86_64 pe-coff now supports the --build-id option.
 172
 173 * Add support for the Andes NDS32.
 174
 175 Changes in 2.24:
 176
 177 * Add LOG2CEIL() builtin function to the linker script language
 178
 179 * Add support for the Texas Instruments MSP430X processor.
 180
 181 * Add support for Altera Nios II.
 182
 183 * Add support for the V850E3V5 architecture.
 184
 185 * Add support for the Imagination Technologies Meta processor.
 186
 187 * --enable-new-dtags no longer generates old dtags in addition to new dtags.
 188
 189 * Remove linker support for MIPS ECOFF targets.
 190
 191 * Add ALIGN_WITH_INPUT to the linker script language to force the alignment of
 192   an output section to use the maximum alignment of all its input sections.
 193
 194 Changes in 2.23:
 195
 196 * Enable compressed debug section feature for x86/x86_64 pe-coff.
 197
 198 * Add support for the 64-bit ARM architecture: AArch64.
 199
 200 * Added SORT_NONE to the linker script language to disable section sorting.
 201
 202 * Add a linker-provided symbol when producing ELF output, '__ehdr_start'
 203   to point to the ELF file header (and nearby program headers) in the
 204   program's memory image.
 205
 206 * Add support for S12X processor.
 207
 208 * Add support for the VLE extension to the PowerPC architecture.
 209
 210 * Add support for the Freescale XGATE architecture.
 211
 212 * Add option -f FILE on AIX (for response file).
 213
 214 * Add support for the Renesas RL78 architecture.
 215
 216 * Add support for the Adapteva EPIPHANY architecture.
 217
 218 Changes in 2.22:
 219
 220 * --copy-dt-needed-entries is no longer enabled by default.  Instead
 221   --no-copy-dt-needed-entries is the default.
 222
 223 * INPUT_SECTION_FLAGS has been added to the linker script language
 224   to allow selection of input sections by section header section flags.
 225
 226 * Add support for the Tilera TILEPro and TILE-Gx architectures.
 227
 228 * Added SORT_BY_INIT_PRIORITY to the linker script language to permit
 229   sorting sections by numerical value of the GCC init_priority attribute
 230   encoded in the section name.
 231
 232 Changes in 2.21:
 233
 234 * Linker script expression evaluation is somewhat more sane.  This may
 235   break scripts that depend on quirks of the old expression evaluation.
 236
 237 * Turn off underscoring for x86_64 PE+-COFF targets.  For old behavior the
 238   option --enable-leading-mingw64-underscores can be used on configure of
 239   bfd.
 240
 241 * Add support for the TMS320C6000 (TI C6X) processor family.
 242
 243 * --add-needed renamed to --copy-dt-needed-entries in order to avoid confusion
 244   with --as-needed option.
 245
 246 * Extend .def file syntax by '== <ID>' for imports and exports. This allows
 247   to alias the import/export table name written in PE image.
 248
 249 * Add --exclude-all-symbols option to PE based linkers.  This prevents all
 250   symbols from automatically being exported.
 251
 252 * Add support for the Renesas RX processor.
 253
 254 * Add support for alpha-vms target.
 255
 256 Changes in 2.20:
 257
 258 * GNU/Linux targets now support the STB_GNU_UNIQUE symbol binding.  This is a
 259   GNU extension to the standard set of ELF symbol bindings.  The binding will
 260   be passed on to the dynamic linker which will make sure that in the entire
 261   process there is just one symbol with the given name and type in use.
 262
 263 * PE targets now support a GNU extension to allow the alignment of common
 264   common symbols to be specified.  This support uses custom options in
 265   the .drectve section, which will be disregarded by the native tools.
 266
 267 * PE targets now add primitive support for ELF version scripts; symbols
 268   are not versioned, but the local and global symbol visibility directives
 269   are respected when filtering symbols in auto-export mode.
 270
 271 * New option --no-export-dynamic to undo the effect of the -E and
 272   --export-dynamic options.
 273
 274 * ELF: --warn-alternate-em option to warn if an object has alternate
 275   ELF machine code.
 276
 277 * New script function REGION_ALIAS to add alias names to memory regions.
 278
 279 * PE targets no longer make use of the long section names PE extension to
 280   the COFF format when generating executable images, by default.  The old
 281   (slightly non-conformant) behaviour can still be invoked by using the
 282   new '--enable-long-section-names' command-line option.  It is also enabled
 283   automatically in the presence of un-stripped debug information, as GDB
 284   needs to be able to find the debug info sections by their full names.
 285
 286 * For GNU/Linux systems the linker will now avoid processing any relocations
 287   made against symbols of the STT_GNU_IFUNC type and instead emit them into
 288   the resulting binary for processing by the loader.
 289
 290 * --as-needed now links in a dynamic library if it satisfies undefined
 291   symbols in regular objects, or in other dynamic libraries.  In the
 292   latter case the library is not linked if it is found in a DT_NEEDED
 293   entry of one of the libraries already linked.
 294
 295 * Add a new command-line option, -Ttext-segment ADDR, for ELF targets
 296   to set the address of the first byte of the text segment.
 297
 298 * Add support for Sunplus score architecture.
 299
 300 * Add new option --use-nul-prefixed-import-tables to ld for PE targets to
 301   allow fallback to old import table generation with null element prefix.
 302
 303 * Windows PE systems now support a new --exclude-modules-for-implib option,
 304   allowing users to partition object files and archive members between a DLL
 305   and its associated import library as they are generated during linking.
 306
 307 * Add support for Lattice Mico32 (lm32) architecture.
 308
 309 * Add CR16 ELF --embedded-relocs (used to embedded relocations into binaries
 310   for Embedded-PIC code) option.
 311
 312 * Add to the PE/PE+ targets the support of two different kinds of
 313   pseudo-relocations.  They can be selected by the switches
 314   --enable-runtime-pseudo-reloc-v1 and --enable-runtime-pseudo-reloc-v2.
 315   For the switch --enable-runtime-pseudo-reloc it uses for 32-bit
 316   runtime pseudo relocation version one, for 64-bit the version two.
 317
 318 Changes in 2.19:
 319
 320 * Linker scripts support a new INSERT command that makes it easier to
 321   augment the default script.
 322
 323 * Linker script input section filespecs may now specify a file within an
 324   archive by writing "archive:file".
 325
 326 * The --sort-common switch now has an optional argument which specifies the
 327   direction of sorting.
 328
 329 * The M68K linker now supports multiple GOT generation schemes controlled via
 330   the --got=<type> command-line option.
 331
 332 * The ARM EABI linker will now generate stubs for function calls to symbols
 333   that are too far away.  The placement of the stubs is controlled by a new
 334   linker command-line option: --stub-group-size=N.
 335
 336 Changes in 2.18:
 337
 338 * Linker sources now released under version 3 of the GNU General Public
 339   License.
 340
 341 * ELF: New --build-id option to generate a unique per-binary identifier
 342   embedded in a note section.
 343
 344 * Added support for National Semicondutor CompactRISC (ie CR16) target.
 345
 346 * -l:foo now searches the library path for a filename called foo,
 347   without converting it to libfoo.a or libfoo.so.
 348
 349 * Add a new command-line option '--default-script=FILE' or '-dT FILE'
 350   which specifies a replacement for the built in, default linker
 351   script.
 352
 353 * ELF: Add -Bsymbolic-functions, --dynamic-list-cpp-new, which puts C++
 354   operator new and delete on the dynamic list, and --dynamic-list-data,
 355   builtin list for --dynamic-list, which puts global data symbols on the
 356   dynamic list.
 357
 358 * Add support for x86_64 PE+ target.
 359
 360 * Add support for Score target.
 361
 362 * ELF: Add --dynamic-list option to specify a list of global symbols
 363   whose references shouldn't be bound to the definition within the
 364   shared library, or a list of symbols which should be added to the
 365   symbol table in the executable.
 366
 367 * The default output section LMA has changed for allocatable sections from
 368   being equal to VMA, to keeping the difference between LMA and VMA the same as
 369   the previous output section in the same region.  This is a more useful
 370   default when using overlays and other cases where you specify an LMA
 371   differing from the VMA for some sections.
 372
 373 * New switch: --print-gc-sections to list any sections removed by garabge
 374   collection.
 375
 376 * ARM: Added --vfp11-denorm-fix option to work around an erratum in current
 377   VFP11 coprocessors.
 378
 379 Changes in 2.17:
 380
 381 * Support for the Infineon XC16X has been added by KPIT Cummins Infosystems.
 382
 383 * Modify the Linux linker search order to better match ld.so search order.
 384   Look for DT_NEEDED libraries in paths specified by ld.so.conf before
 385   searching the default directories, rather than vice versa.
 386   Use $prefix/etc/ld.so.conf if it exists, otherwise /etc/ld.so.conf.
 387
 388 * PE-COFF: Forward exports from DLL's can now be specified in .def files
 389   passed directly to ld.
 390
 391 * Support for the Z80 processor family has been added.
 392
 393 * Add support for the "@<file>" syntax to the command line, so that extra
 394   switches can be read from <file>.
 395
 396 Changes in 2.16:
 397
 398 * Support for the R_ARM_V4BX relocation as defined in the ARM AAELF
 399   specification has been added via the --fix-v4bx command-line option.
 400
 401 * New linker script construct AS_NEEDED(), which sets the --as-needed flag
 402   for input files listed inside of it.
 403
 404 * A new command-line option, --sysroot, can be used to override the
 405   default sysroot location.  It only applies to toolchains that were
 406   configured using --with-sysroot.
 407
 408 * New linker script functions: ORIGIN() and LENGTH() which return information
 409   about a specified memory region.
 410
 411 * Port to MAXQ processor contributed by HCL Tech.
 412
 413 * Added SEGMENT_START to the linker script language to permit the user to
 414   override the base address for a segment from the command-line.
 415
 416 * ELF: --warn-shared-textrel option to warn if adding a DT_TEXTREL to a shared
 417   object.
 418
 419 * Added SORT_BY_NAME and SORT_BY_ALIGNMENT to the linker script
 420   language to permit sorting sections by section name or section
 421   maximum alignment.
 422
 423 * Added a new linker command-line switch, --sort-section name|alignment,
 424   to sort sections by section name or maximum alignment.
 425
 426 * ELF: --add-needed/--no-add-needed options to control if a DT_NEEDED tag
 427   should be added when a shared library comes from DT_NEEDED tags.
 428
 429 * Support for the crx-elf target added.
 430
 431 * Support for the sh-symbianelf target added.
 432
 433 * A new linker command-line switch has been added which allows the hash table
 434   size to be set to a suitable prime value near to its argument.  This switch
 435   is --hash-size=<NUMBER>.  Also if the switch --reduce-memory-overheads is
 436   used, and --hash-size has not been used, then the default value will be set
 437   to 1021.
 438
 439 * Linker map files are now generated with an O(N) algorithm for finding symbols
 440   that are defined in each section.  This uses about 40% more memory for
 441   symbols than the old O(N^2) algorithm.  You can use the new
 442   --reduce-memory-overheads option to select the old algorithm; this option
 443   might also be used in the future to select similar tradeoffs.
 444
 445 Changes in 2.15:
 446
 447 * ELF: --as-needed/--no-as-needed options to control if a DT_NEEDED tag should
 448   be added only when a shared library is referenced.
 449
 450 * PE: --large-address-aware option to indicate executables support virtual
 451   addresses greater than 2 gigabytes.
 452
 453 * DWARF 2 support for i386pe added.
 454
 455 * The linker script operator DEFINED() will now yield 1 only for a symbol that
 456   is defined before the statement where DEFINED is used.
 457
 458 * The MIPS --embedded-relocs (used to embed relocations into binaries for
 459   Embedded-PIC code) is deprecated and will be removed in a future release.
 460
 461 * cr16c support added by NSC.
 462
 463 * m32r Linux (ELF) support added by Renesas.
 464
 465 * Improved linker's handling of unresolved symbols.  The switch
 466   --unresolved-symbols=<method> has been added to tell the linker when it
 467   should report them and the switch --warn-unresolved-symbols has been added to
 468   make reports be issued as warning messages rather than errors.
 469
 470 Changes in 2.14:
 471
 472 * Added support for Xtensa architecture.
 473
 474 * Added --with-sysroot configure switch to specify a target system root, for
 475   linking against a target filesystem image.
 476
 477 * Added --accept-unknown-linker-format to restore old linker behaviour (pre
 478   2.14) of silently accepting and linking in any files in an unknown binary
 479   file format.
 480
 481 * Added --no-omagic to undo the effects of the -N option.
 482
 483 * Support for Texas Instruments TMS320C4x and TMS320C3x series of
 484   DSP's contributed by Michael Hayes and Svein E. Seldal.
 485
 486 * Added --with-lib-path configure switch to specify default value for
 487   LIB_PATH.
 488
 489 * ARM port to QNX operating system added by Graeme Peterson.
 490
 491 * IP2K support added by Denis Chertykov.
 492
 493 Changes in 2.13:
 494
 495 * Support for the Fujitsu FRV architecture added by Red Hat. Models for FR400
 496   and FR500 included.
 497
 498 Changes in version 2.13:
 499
 500 * DEC VAX ELF support, by Matt Thomas.
 501
 502 Changes in version 2.12:
 503
 504 * Support for Don Knuth's MMIX, by Hans-Peter Nilsson.
 505
 506 * Support for the OpenRISC 32-bit embedded processor by OpenCores.
 507
 508 * Support for -z nocopyreloc in the x86 ELF linker, which disables
 509   production of copy relocs.  Warning: using this option may result in
 510   non-sharable applications.
 511
 512 * Support for -z combreloc in the ELF linker, which puts dynamic
 513   relocations against the same symbol together, so that dynamic linker
 514   can use an one-entry symbol lookup cache.
 515
 516 * Support for ELF SHF_MERGE section merging, by Jakub Jelinek.
 517
 518 Changes in version 2.11:
 519
 520 * Support for AMD x86-64 architecture, by Jan Hubicka, SuSE Labs.
 521
 522 * Support added for eliminating duplicate DWARF2 debug information by
 523   having the compiler generate the information in sections called
 524   .gnu.linkonce.wi.XXXX where XXXX is a checksum for the contents.  The
 525   linker then merges these sections together into the normal .debug_info
 526   section.
 527
 528 * The native ELF linker now searches the directories in DT_RUNPATH or
 529   DT_RPATH of a shared library for shared libraries needed by it.
 530
 531 * TI C54x support, by Timothy Wall.
 532
 533 * Added command-line switch --section-start to set the start address of any
 534   specified section.
 535
 536 * Added ability to emit full relocation information in linked executables,
 537   enabled by --emit-relocs.  Some post-linkage optimization tools need
 538   this information in order to be able to correctly identify and perform
 539   symbol relative addressing in the event of changes in section contents
 540   (instructions being added or deleted, extending data sections, etc.)
 541
 542 * Support for i860, by Jason Eckhardt (preliminary, alpha quality).
 543
 544 * Support for CRIS (Axis Communications ETRAX series).
 545
 546 * Support for PDP-11 and 2.11BSD a.out format, by Lars Brinkhoff.
 547
 548 Changes in version 2.10:
 549
 550 * Added AT> to the linker script language to allow load-time allocation of
 551   sections into regions.
 552
 553 * Added garbage collection of unused sections, enabled by --gc-sections.
 554   It does require a bit of backend support; currently implemented are
 555   arm-elf, avr-elf, d10v-elf, fr30-elf, i386-elf, m32r-elf, m68k-elf,
 556   mcore-elf, mips-elf, mn10300-elf, ppc-elf, sh-elf, sparc-elf, and v850-elf.
 557   Others will ignore the option.
 558
 559 * Added SORT to the linker script language to permit sorting sections by file
 560   name or section name.
 561
 562 * Added EXTERN to the linker script language as an equivalent to the -u
 563   command-line option.
 564
 565 * Added ASSERT to the linker script language.
 566
 567 * Added EXCLUDE_FILE to the linker script language for further control over
 568   wildcard file names.
 569
 570 * Added -O option to optimize linker output (as of this writing, this only
 571   affects ELF shared library generation).
 572
 573 * The -e option now accepts a number as well as a symbol name.
 574
 575 * Added --no-undefined option to disallow undefined symbols when creating a
 576   shared library.
 577
 578 * The linker now issues a warning, not an error, for an undefined symbol when
 579   using -Bsymbolic; use the new --no-undefined option to get the old
 580   behaviour.
 581
 582 * Added --demangle and --no-demangle options.
 583
 584 Changes in version 2.9:
 585
 586 * Added SQUAD to the linker script language.
 587
 588 * New option --no-warn-mismatch.
 589
 590 * The MEMORY command now parses the attributes to determine where sections that
 591   are not placed in a specific memory region are placed.
 592
 593 Changes in version 2.8:
 594
 595 * Linker scripts may now contain shell wildcard characters for file and section
 596   names.
 597
 598 * The linker now supports symbol versions in ELF.
 599
 600 * The NOCROSSREFS command was added to the linker script language.
 601
 602 * The LOADADDR expression was added to the linker script language.
 603
 604 * MAX and MIN functions were added to the linker script language.
 605
 606 * The OVERLAY construct was added to the linker script language.
 607
 608 * New option --warn-section-align to warn when the address of an output section
 609   changes due to alignment of an input section.
 610
 611 * New options --filter/-F and --auxiliary/-f.
 612
 613 Changes in version 2.7:
 614
 615 * New option --cref to print out a cross reference table.
 616
 617 * New option --wrap SYMBOL.
 618
 619 * New option --no-whole-archive, to turn off the effect of --whole-archive.
 620
 621 * Input sections assigned to the output section /DISCARD/ in the linker script
 622   are not included in the output file.
 623
 624 * The SunOS and ELF linkers now merge stabs debugging information which uses
 625   the N_BINCL and N_EINCL stab types.  This reduces the amount of debugging
 626   information generated.
 627
 628 Changes in version 2.6:
 629
 630 * When an ELF section name is representable as a C identifier (this is not true
 631 of most ELF section names), the linker will automatically define symbols
 632 __start_SECNAME and __stop_SECNAME, where SECNAME is the section name, at the
 633 beginning and the end of the section.  This is used by glibc.
 634
 635   Addendum: Current versions of the linker (at least for version 2.18 onwards
 636 and possibly much earlier as well) place two restrictions on this feature:  The
 637 symbols are only implemented for orphaned sections, not for explicitly placed
 638 sections and they are PROVIDEd rather than being defined.
 639
 640 * When an ELF section named .gnu.warning is encountered in an input file, the
 641 contents of the section are displayed as an error message, and the section is
 642 not copied into the output file.  This is used by glibc.
 643
 644 * When an ELF section named .gnu.warning.SYMBOL is encountered in an input
 645 file, and the symbol SYMBOL is referenced by some object file, the contents of
 646 the section are displayed as an error message.  The section is not copied into
 647 the output file, unless doing a relocatable or shared link.  This is used by
 648 glibc.
 649
 650 * New options -split-by-reloc and -split-by-file.
 651
 652 * The linker now supports linking PIC compiled code on SPARC SunOS.  It can
 653 also create SPARC SunOS shared libraries, and, like the native SunOS linker,
 654 will do so whenever there is an undefined symbol in the link and neither the -e
 655 nor the -r option was used.
 656
 657 * The -rpath option may be used on SunOS to set the list of directories to be
 658 searched at run time.  This overrides the default of building the list from the
 659 -L options.
 660
 661 * The COFF linker now combines debugging information for structs, unions, and
 662 enums, so that even if the same type is defined in multiple input files it will
 663 only be defined once in the output file.  The --traditional-format switch will
 664 prevent this optimization.
 665
 666 Changes in version 2.5:
 667
 668 * The linker now supports linking against SunOS shared libraries.  It still can
 669 not link SunOS PIC (Position Independent Code) files, so it can not be used to
 670 generate shared libraries.
 671
 672 * The linker now supports linking against ELF shared libraries for the i386
 673 (UnixWare) and SPARC (Solaris).  It can also link ELF PIC files, and can be
 674 used to generate shared libraries.  Shared library generation is not well
 675 tested; please report any problems encountered.  The linker is now enabled for
 676 Solaris again.
 677
 678 * Eric Youngdale has contributed Linux support code, including linking against
 679 Linux a.out shared libraries.  The linker produces Linux QMAGIC binaries.
 680
 681 * The ELF backend has been converted to the new linker code.  To use the new
 682 ELF linker, each particular target requires a relocation function.  So far,
 683 this function has been written for i386 (UnixWare), SPARC (Solaris) MIPS (Irix
 684 5), and HPPA ELF targets.
 685
 686 * The -( (--start-group) and -) (--end-group) options have been added to
 687 support searching a group of archives as though they were a single archive.
 688 This can also be used in a linker script, as GROUP ( files ).
 689
 690 * When a file is named on the command line, and the linker does not recognize
 691 it as an object file, the linker will now treat the file as a linker script
 692 file.  A linker script named in this way augments, but does not replace, the
 693 default linker script.
 694
 695 * The -warn-once option was added.  It causes the linker to only warn once per
 696 undefined symbol, rather than once per reference.
 697
 698 * The COFF backend has been converted to the new linker code.  As with ELF, to
 699 use the new linker, each particular target requires a relocation function.  So
 700 far, this function has been written for the i386, m68k, a29k and SH targets.
 701
 702 * The -V flag was made a synonym for -v, for SVR4 compatibility.  The old -V
 703 behaviour is available via --verbose.
 704
 705 Changes in version 2.4:
 706
 707 * New linker code, by Steve Chamberlain and Ian Taylor.  For a.out and ecoff
 708   formats (so far), this should result in considerable savings in time
 709   and memory used while linking; slightly poorer performance than
 710   before for formats not converted yet.
 711
 712 * Command-line parsing is no longer done with flex.  This means
 713   oddball characters in filenames won't get treated as argument
 714   separators.
 715
 716 * HP-PA ELF support, by Jeff Law.  (No SOM support yet.)
 717
 718 * Mach i386 support, by David Mackenzie.
 719
 720 * Irix 4 shared libraries are now supported (Irix 5 uses ELF, and ELF shared
 721   libraries are not yet supported).
 722
 723 * COFF shared libraries (as on SCO) should work as well.
 724
 725 * The linker is disabled for Solaris.  (Actually, it was in 2.3 also, I just
 726   forgot to note it.)  Some of their C library routines don't work when
 727   statically linked, and the GNU linker doesn't support dynamic linking yet.
 728
 729 Changes in version 2.3:
 730
 731 * Weak symbols are now supported.
 732
 733 * ELF support has been added.  The linker has been bootstrapped on
 734   UnixWare and Solaris.
 735
 736 * Alpha OSF/1 support has been added (non dynamic linking only).
 737
 738 Changes in version 2.2:
 739
 740 * The `bfd' library has been updated to reduce a.out-format string
 741   table size.  The effect of this is that files linked from many input
 742   files with duplicate symbols (`-g' debugging records, or identical
 743   static symbols) should be much smaller.
 744
 745 Changes in version 2.1:
 746
 747 * The ld -ySYMBOL flag (to trace references to SYMBOL) is now implemented.
 748
 749 * There is now support for writing ECOFF files, so ld and the
 750   other utilities should work on Risc/Ultrix and Irix.
 751
 752 \f
 753 Copyright (C) 2012-2019 Free Software Foundation, Inc.
 754
 755 Copying and distribution of this file, with or without modification,
 756 are permitted in any medium without royalty provided the copyright
 757 notice and this notice are preserved.
 758
 759 Local variables:
 760 fill-column: 79
 761 End: