ld/NEWS

   1 -*- text -*-
   2
   3 * Add command-line option --no-print-map-discarded.
   4
   5 Changes in 2.33:
   6
   7 * Add target handlers for AArch64 for ELF GNU program properties.
   8
   9 * Add support for GNU_PROPERTY_AARCH64_FEATURE_1_BTI in ELF GNU program
  10   properties in the AArch64 ELF linker.
  11
  12 * Add support for GNU_PROPERTY_AARCH64_FEATURE_1_PAC in ELF GNU program
  13   properties in the AArch64 ELF linker.
  14
  15 * Add --force-bti for AArch64 to enable GNU_PROPERTY_AARCH64_FEATURE_1_BTI
  16   on output while warning about missing GNU_PROPERTY_AARCH64_FEATURE_1_BTI
  17   on inputs and use PLTs protected with BTI.
  18
  19 * Add --pac-plt for AArch64 to pick PAC enabled PLTs.
  20
  21 Changes in 2.32:
  22
  23 * Report property change in linker map file when merging GNU properties.
  24
  25 * Add support for the C-SKY processor series.
  26
  27 * -t now doesn't report members within archives, unless -t is given twice.
  28   A single -t is now more useful when generating a list of files that should be
  29   packaged for a linker bug report.  For example:
  30     gcc hello.c -save-temps -Wl,-t | xargs realpath | sort | uniq > files
  31     tar cJf test.tar.xz `cat files`
  32
  33 Changes in 2.31:
  34
  35 * Speed up direct linking with DLLs for Cygwin and Mingw targets.
  36
  37 * Add a configure option --enable-separate-code to decide whether
  38   -z separate-code should be enabled in ELF linker by default.  Default
  39   to yes for Linux/x86 targets.  Note that -z separate-code can increase
  40   disk and memory size.
  41
  42 Changes in 2.30:
  43
  44 * Add -z separate-code to generate separate code PT_LOAD segment.
  45
  46 * Add "-z undefs" command-line option as the inverse of the "-z defs" option.
  47
  48 * Add -z globalaudit command-line option to force audit libraries to be run
  49   for every dynamic object loaded by an executable - provided that the loader
  50   supports this functionality.
  51
  52 * Tighten linker script grammar around file name specifiers to prevent the use
  53   of SORT_BY_ALIGNMENT and SORT_BY_INIT_PRIORITY on filenames.  These would
  54   previously be accepted but had no effect.
  55
  56 * The EXCLUDE_FILE directive can now be placed within any SORT_* directive
  57   within input section lists.
  58
  59 Changes in 2.29:
  60
  61 * Support for -z shstk in the x86 ELF linker to generate
  62   GNU_PROPERTY_X86_FEATURE_1_SHSTK in ELF GNU program properties.
  63
  64 * Add support for GNU_PROPERTY_X86_FEATURE_1_SHSTK in ELF GNU program
  65   properties in the x86 ELF linker.
  66
  67 * Add support for GNU_PROPERTY_X86_FEATURE_1_IBT in ELF GNU program
  68   properties in the x86 ELF linker.
  69
  70 * Support for -z ibtplt in the x86 ELF linker to generate IBT-enabled
  71   PLT.
  72
  73 * Support for -z ibt in the x86 ELF linker to generate IBT-enabled
  74   PLT as well as GNU_PROPERTY_X86_FEATURE_1_IBT in ELF GNU program
  75   properties.
  76
  77 * Add support for ELF SHF_GNU_MBIND and PT_GNU_MBIND_XXX.
  78
  79 * Add support for ELF GNU program properties.
  80
  81 * Add support for the Texas Instruments PRU processor.
  82
  83 * When configuring for arc*-*-linux* targets the default linker emulation will
  84   change if --with-cpu=nps400 is used at configure time.
  85
  86 * Improve assignment of LMAs to orphan sections in some edge cases where a
  87   mixture of both AT>LMA_REGION and AT(LMA) are used.
  88
  89 * Orphan sections placed after an empty section that has an AT(LMA) will now
  90   take an load memory address starting from LMA.
  91
  92 * Section groups can now be resolved (the group deleted and the group members
  93   placed like normal sections) at partial link time either using the new linker
  94   option --force-group-allocation or by placing FORCE_GROUP_ALLOCATION into the
  95   linker script.
  96
  97 Changes in 2.28:
  98
  99 * The EXCLUDE_FILE linker script construct can now be applied outside of the
 100   section list in order for the exclusions to apply over all input sections in
 101   the list.
 102
 103 * Add support for the RISC-V architecture.
 104
 105 * The command-line option --no-eh-frame-hdr can now be used in ELF based
 106   linkers to disable the automatic generation of .eh_frame_hdr sections.
 107
 108 * Add --in-implib=<infile> to the ARM linker to enable specifying a set of
 109   Secure Gateway veneers that must exist in the output import library specified
 110   by --out-implib=<outfile> and the address they must have.  As such,
 111   --in-implib is only supported in combination with --cmse-implib.
 112
 113 * Extended the --out-implib=<file> option, previously restricted to x86 PE
 114   targets, to any ELF based target.  This allows the generation of an import
 115   library for an ELF executable, which can then be used by another application
 116   to link against the executable.
 117
 118 Changes in 2.27:
 119
 120 * Add a configure option --enable-relro to decide whether -z relro should
 121   be enabled in ELF linker by default.  Default to yes for all Linux
 122   targets except FRV, HPPA, IA64 and MIPS.  Note that -z relro can increase
 123   disk and memory size.
 124
 125 * Support for -z noreloc-overflow in the x86-64 ELF linker to disable
 126   relocation overflow check.
 127
 128 * Add -z common/-z nocommon options for ELF targets to control whether to
 129   convert common symbols to the STT_COMMON type during a relocatable link.
 130
 131 * Support for -z nodynamic-undefined-weak in the x86 ELF linker, which
 132   avoids dynamic relocations against undefined weak symbols in executable.
 133
 134 * The NOCROSSREFSTO command was added to the linker script language.
 135
 136 * Add --no-apply-dynamic-relocs to the AArch64 linker to do not apply link-time
 137   values for dynamic relocations.
 138
 139 Changes in 2.26:
 140
 141 * Add --fix-stm32l4xx-629360 to the ARM linker to enable a link-time
 142   workaround for a bug in the bus matrix / memory controller for some of
 143   the STM32 Cortex-M4 based products (STM32L4xx)
 144
 145 * Add a configure option --enable-compressed-debug-sections={all,ld} to
 146   decide whether DWARF debug sections should be compressed by default.
 147
 148 * Add support for the ARC EM/HS, and ARC600/700 architectures.
 149
 150 * Experimental support for linker garbage collection (--gc-sections)
 151   has been enabled for COFF and PE based targets.
 152
 153 * New command-line option for ELF targets to compress DWARF debug
 154   sections, --compress-debug-sections=[none|zlib|zlib-gnu|zlib-gabi].
 155
 156 * New command-line option, --orphan-handling=[place|warn|error|discard], to
 157   adjust how orphan sections are handled.  The default is 'place' which gives
 158   the current behaviour, 'warn' and 'error' issue a warning or error
 159   respectively when orphan sections are found, and 'discard' will discard all
 160   orphan sections.
 161
 162 * Add support for LLVM plugin.
 163
 164 * Add --print-memory-usage option to report memory blocks usage.
 165
 166 * Add --require-defined option, it's like --undefined except the new symbol
 167   must be defined by the end of the link.
 168
 169 Changes in 2.25:
 170
 171 * PE binaries now once again contain real timestamps by default.  To disable
 172   the inclusion of a timestamp in a PE binary, use the --no-insert-timestamp
 173   command-line option.
 174
 175 * Replace support for openrisc and or32 with support for or1k.
 176
 177 * Add support for the --build-id command-line option to COFF based targets.
 178
 179 * x86/x86_64 pe-coff now supports the --build-id option.
 180
 181 * Add support for the Andes NDS32.
 182
 183 Changes in 2.24:
 184
 185 * Add LOG2CEIL() builtin function to the linker script language
 186
 187 * Add support for the Texas Instruments MSP430X processor.
 188
 189 * Add support for Altera Nios II.
 190
 191 * Add support for the V850E3V5 architecture.
 192
 193 * Add support for the Imagination Technologies Meta processor.
 194
 195 * --enable-new-dtags no longer generates old dtags in addition to new dtags.
 196
 197 * Remove linker support for MIPS ECOFF targets.
 198
 199 * Add ALIGN_WITH_INPUT to the linker script language to force the alignment of
 200   an output section to use the maximum alignment of all its input sections.
 201
 202 Changes in 2.23:
 203
 204 * Enable compressed debug section feature for x86/x86_64 pe-coff.
 205
 206 * Add support for the 64-bit ARM architecture: AArch64.
 207
 208 * Added SORT_NONE to the linker script language to disable section sorting.
 209
 210 * Add a linker-provided symbol when producing ELF output, '__ehdr_start'
 211   to point to the ELF file header (and nearby program headers) in the
 212   program's memory image.
 213
 214 * Add support for S12X processor.
 215
 216 * Add support for the VLE extension to the PowerPC architecture.
 217
 218 * Add support for the Freescale XGATE architecture.
 219
 220 * Add option -f FILE on AIX (for response file).
 221
 222 * Add support for the Renesas RL78 architecture.
 223
 224 * Add support for the Adapteva EPIPHANY architecture.
 225
 226 Changes in 2.22:
 227
 228 * --copy-dt-needed-entries is no longer enabled by default.  Instead
 229   --no-copy-dt-needed-entries is the default.
 230
 231 * INPUT_SECTION_FLAGS has been added to the linker script language
 232   to allow selection of input sections by section header section flags.
 233
 234 * Add support for the Tilera TILEPro and TILE-Gx architectures.
 235
 236 * Added SORT_BY_INIT_PRIORITY to the linker script language to permit
 237   sorting sections by numerical value of the GCC init_priority attribute
 238   encoded in the section name.
 239
 240 Changes in 2.21:
 241
 242 * Linker script expression evaluation is somewhat more sane.  This may
 243   break scripts that depend on quirks of the old expression evaluation.
 244
 245 * Turn off underscoring for x86_64 PE+-COFF targets.  For old behavior the
 246   option --enable-leading-mingw64-underscores can be used on configure of
 247   bfd.
 248
 249 * Add support for the TMS320C6000 (TI C6X) processor family.
 250
 251 * --add-needed renamed to --copy-dt-needed-entries in order to avoid confusion
 252   with --as-needed option.
 253
 254 * Extend .def file syntax by '== <ID>' for imports and exports. This allows
 255   to alias the import/export table name written in PE image.
 256
 257 * Add --exclude-all-symbols option to PE based linkers.  This prevents all
 258   symbols from automatically being exported.
 259
 260 * Add support for the Renesas RX processor.
 261
 262 * Add support for alpha-vms target.
 263
 264 Changes in 2.20:
 265
 266 * GNU/Linux targets now support the STB_GNU_UNIQUE symbol binding.  This is a
 267   GNU extension to the standard set of ELF symbol bindings.  The binding will
 268   be passed on to the dynamic linker which will make sure that in the entire
 269   process there is just one symbol with the given name and type in use.
 270
 271 * PE targets now support a GNU extension to allow the alignment of common
 272   common symbols to be specified.  This support uses custom options in
 273   the .drectve section, which will be disregarded by the native tools.
 274
 275 * PE targets now add primitive support for ELF version scripts; symbols
 276   are not versioned, but the local and global symbol visibility directives
 277   are respected when filtering symbols in auto-export mode.
 278
 279 * New option --no-export-dynamic to undo the effect of the -E and
 280   --export-dynamic options.
 281
 282 * ELF: --warn-alternate-em option to warn if an object has alternate
 283   ELF machine code.
 284
 285 * New script function REGION_ALIAS to add alias names to memory regions.
 286
 287 * PE targets no longer make use of the long section names PE extension to
 288   the COFF format when generating executable images, by default.  The old
 289   (slightly non-conformant) behaviour can still be invoked by using the
 290   new '--enable-long-section-names' command-line option.  It is also enabled
 291   automatically in the presence of un-stripped debug information, as GDB
 292   needs to be able to find the debug info sections by their full names.
 293
 294 * For GNU/Linux systems the linker will now avoid processing any relocations
 295   made against symbols of the STT_GNU_IFUNC type and instead emit them into
 296   the resulting binary for processing by the loader.
 297
 298 * --as-needed now links in a dynamic library if it satisfies undefined
 299   symbols in regular objects, or in other dynamic libraries.  In the
 300   latter case the library is not linked if it is found in a DT_NEEDED
 301   entry of one of the libraries already linked.
 302
 303 * Add a new command-line option, -Ttext-segment ADDR, for ELF targets
 304   to set the address of the first byte of the text segment.
 305
 306 * Add support for Sunplus score architecture.
 307
 308 * Add new option --use-nul-prefixed-import-tables to ld for PE targets to
 309   allow fallback to old import table generation with null element prefix.
 310
 311 * Windows PE systems now support a new --exclude-modules-for-implib option,
 312   allowing users to partition object files and archive members between a DLL
 313   and its associated import library as they are generated during linking.
 314
 315 * Add support for Lattice Mico32 (lm32) architecture.
 316
 317 * Add CR16 ELF --embedded-relocs (used to embedded relocations into binaries
 318   for Embedded-PIC code) option.
 319
 320 * Add to the PE/PE+ targets the support of two different kinds of
 321   pseudo-relocations.  They can be selected by the switches
 322   --enable-runtime-pseudo-reloc-v1 and --enable-runtime-pseudo-reloc-v2.
 323   For the switch --enable-runtime-pseudo-reloc it uses for 32-bit
 324   runtime pseudo relocation version one, for 64-bit the version two.
 325
 326 Changes in 2.19:
 327
 328 * Linker scripts support a new INSERT command that makes it easier to
 329   augment the default script.
 330
 331 * Linker script input section filespecs may now specify a file within an
 332   archive by writing "archive:file".
 333
 334 * The --sort-common switch now has an optional argument which specifies the
 335   direction of sorting.
 336
 337 * The M68K linker now supports multiple GOT generation schemes controlled via
 338   the --got=<type> command-line option.
 339
 340 * The ARM EABI linker will now generate stubs for function calls to symbols
 341   that are too far away.  The placement of the stubs is controlled by a new
 342   linker command-line option: --stub-group-size=N.
 343
 344 Changes in 2.18:
 345
 346 * Linker sources now released under version 3 of the GNU General Public
 347   License.
 348
 349 * ELF: New --build-id option to generate a unique per-binary identifier
 350   embedded in a note section.
 351
 352 * Added support for National Semicondutor CompactRISC (ie CR16) target.
 353
 354 * -l:foo now searches the library path for a filename called foo,
 355   without converting it to libfoo.a or libfoo.so.
 356
 357 * Add a new command-line option '--default-script=FILE' or '-dT FILE'
 358   which specifies a replacement for the built in, default linker
 359   script.
 360
 361 * ELF: Add -Bsymbolic-functions, --dynamic-list-cpp-new, which puts C++
 362   operator new and delete on the dynamic list, and --dynamic-list-data,
 363   builtin list for --dynamic-list, which puts global data symbols on the
 364   dynamic list.
 365
 366 * Add support for x86_64 PE+ target.
 367
 368 * Add support for Score target.
 369
 370 * ELF: Add --dynamic-list option to specify a list of global symbols
 371   whose references shouldn't be bound to the definition within the
 372   shared library, or a list of symbols which should be added to the
 373   symbol table in the executable.
 374
 375 * The default output section LMA has changed for allocatable sections from
 376   being equal to VMA, to keeping the difference between LMA and VMA the same as
 377   the previous output section in the same region.  This is a more useful
 378   default when using overlays and other cases where you specify an LMA
 379   differing from the VMA for some sections.
 380
 381 * New switch: --print-gc-sections to list any sections removed by garabge
 382   collection.
 383
 384 * ARM: Added --vfp11-denorm-fix option to work around an erratum in current
 385   VFP11 coprocessors.
 386
 387 Changes in 2.17:
 388
 389 * Support for the Infineon XC16X has been added by KPIT Cummins Infosystems.
 390
 391 * Modify the Linux linker search order to better match ld.so search order.
 392   Look for DT_NEEDED libraries in paths specified by ld.so.conf before
 393   searching the default directories, rather than vice versa.
 394   Use $prefix/etc/ld.so.conf if it exists, otherwise /etc/ld.so.conf.
 395
 396 * PE-COFF: Forward exports from DLL's can now be specified in .def files
 397   passed directly to ld.
 398
 399 * Support for the Z80 processor family has been added.
 400
 401 * Add support for the "@<file>" syntax to the command line, so that extra
 402   switches can be read from <file>.
 403
 404 Changes in 2.16:
 405
 406 * Support for the R_ARM_V4BX relocation as defined in the ARM AAELF
 407   specification has been added via the --fix-v4bx command-line option.
 408
 409 * New linker script construct AS_NEEDED(), which sets the --as-needed flag
 410   for input files listed inside of it.
 411
 412 * A new command-line option, --sysroot, can be used to override the
 413   default sysroot location.  It only applies to toolchains that were
 414   configured using --with-sysroot.
 415
 416 * New linker script functions: ORIGIN() and LENGTH() which return information
 417   about a specified memory region.
 418
 419 * Port to MAXQ processor contributed by HCL Tech.
 420
 421 * Added SEGMENT_START to the linker script language to permit the user to
 422   override the base address for a segment from the command-line.
 423
 424 * ELF: --warn-shared-textrel option to warn if adding a DT_TEXTREL to a shared
 425   object.
 426
 427 * Added SORT_BY_NAME and SORT_BY_ALIGNMENT to the linker script
 428   language to permit sorting sections by section name or section
 429   maximum alignment.
 430
 431 * Added a new linker command-line switch, --sort-section name|alignment,
 432   to sort sections by section name or maximum alignment.
 433
 434 * ELF: --add-needed/--no-add-needed options to control if a DT_NEEDED tag
 435   should be added when a shared library comes from DT_NEEDED tags.
 436
 437 * Support for the crx-elf target added.
 438
 439 * Support for the sh-symbianelf target added.
 440
 441 * A new linker command-line switch has been added which allows the hash table
 442   size to be set to a suitable prime value near to its argument.  This switch
 443   is --hash-size=<NUMBER>.  Also if the switch --reduce-memory-overheads is
 444   used, and --hash-size has not been used, then the default value will be set
 445   to 1021.
 446
 447 * Linker map files are now generated with an O(N) algorithm for finding symbols
 448   that are defined in each section.  This uses about 40% more memory for
 449   symbols than the old O(N^2) algorithm.  You can use the new
 450   --reduce-memory-overheads option to select the old algorithm; this option
 451   might also be used in the future to select similar tradeoffs.
 452
 453 Changes in 2.15:
 454
 455 * ELF: --as-needed/--no-as-needed options to control if a DT_NEEDED tag should
 456   be added only when a shared library is referenced.
 457
 458 * PE: --large-address-aware option to indicate executables support virtual
 459   addresses greater than 2 gigabytes.
 460
 461 * DWARF 2 support for i386pe added.
 462
 463 * The linker script operator DEFINED() will now yield 1 only for a symbol that
 464   is defined before the statement where DEFINED is used.
 465
 466 * The MIPS --embedded-relocs (used to embed relocations into binaries for
 467   Embedded-PIC code) is deprecated and will be removed in a future release.
 468
 469 * cr16c support added by NSC.
 470
 471 * m32r Linux (ELF) support added by Renesas.
 472
 473 * Improved linker's handling of unresolved symbols.  The switch
 474   --unresolved-symbols=<method> has been added to tell the linker when it
 475   should report them and the switch --warn-unresolved-symbols has been added to
 476   make reports be issued as warning messages rather than errors.
 477
 478 Changes in 2.14:
 479
 480 * Added support for Xtensa architecture.
 481
 482 * Added --with-sysroot configure switch to specify a target system root, for
 483   linking against a target filesystem image.
 484
 485 * Added --accept-unknown-linker-format to restore old linker behaviour (pre
 486   2.14) of silently accepting and linking in any files in an unknown binary
 487   file format.
 488
 489 * Added --no-omagic to undo the effects of the -N option.
 490
 491 * Support for Texas Instruments TMS320C4x and TMS320C3x series of
 492   DSP's contributed by Michael Hayes and Svein E. Seldal.
 493
 494 * Added --with-lib-path configure switch to specify default value for
 495   LIB_PATH.
 496
 497 * ARM port to QNX operating system added by Graeme Peterson.
 498
 499 * IP2K support added by Denis Chertykov.
 500
 501 Changes in 2.13:
 502
 503 * Support for the Fujitsu FRV architecture added by Red Hat. Models for FR400
 504   and FR500 included.
 505
 506 Changes in version 2.13:
 507
 508 * DEC VAX ELF support, by Matt Thomas.
 509
 510 Changes in version 2.12:
 511
 512 * Support for Don Knuth's MMIX, by Hans-Peter Nilsson.
 513
 514 * Support for the OpenRISC 32-bit embedded processor by OpenCores.
 515
 516 * Support for -z nocopyreloc in the x86 ELF linker, which disables
 517   production of copy relocs.  Warning: using this option may result in
 518   non-sharable applications.
 519
 520 * Support for -z combreloc in the ELF linker, which puts dynamic
 521   relocations against the same symbol together, so that dynamic linker
 522   can use an one-entry symbol lookup cache.
 523
 524 * Support for ELF SHF_MERGE section merging, by Jakub Jelinek.
 525
 526 Changes in version 2.11:
 527
 528 * Support for AMD x86-64 architecture, by Jan Hubicka, SuSE Labs.
 529
 530 * Support added for eliminating duplicate DWARF2 debug information by
 531   having the compiler generate the information in sections called
 532   .gnu.linkonce.wi.XXXX where XXXX is a checksum for the contents.  The
 533   linker then merges these sections together into the normal .debug_info
 534   section.
 535
 536 * The native ELF linker now searches the directories in DT_RUNPATH or
 537   DT_RPATH of a shared library for shared libraries needed by it.
 538
 539 * TI C54x support, by Timothy Wall.
 540
 541 * Added command-line switch --section-start to set the start address of any
 542   specified section.
 543
 544 * Added ability to emit full relocation information in linked executables,
 545   enabled by --emit-relocs.  Some post-linkage optimization tools need
 546   this information in order to be able to correctly identify and perform
 547   symbol relative addressing in the event of changes in section contents
 548   (instructions being added or deleted, extending data sections, etc.)
 549
 550 * Support for i860, by Jason Eckhardt (preliminary, alpha quality).
 551
 552 * Support for CRIS (Axis Communications ETRAX series).
 553
 554 * Support for PDP-11 and 2.11BSD a.out format, by Lars Brinkhoff.
 555
 556 Changes in version 2.10:
 557
 558 * Added AT> to the linker script language to allow load-time allocation of
 559   sections into regions.
 560
 561 * Added garbage collection of unused sections, enabled by --gc-sections.
 562   It does require a bit of backend support; currently implemented are
 563   arm-elf, avr-elf, d10v-elf, fr30-elf, i386-elf, m32r-elf, m68k-elf,
 564   mcore-elf, mips-elf, mn10300-elf, ppc-elf, sh-elf, sparc-elf, and v850-elf.
 565   Others will ignore the option.
 566
 567 * Added SORT to the linker script language to permit sorting sections by file
 568   name or section name.
 569
 570 * Added EXTERN to the linker script language as an equivalent to the -u
 571   command-line option.
 572
 573 * Added ASSERT to the linker script language.
 574
 575 * Added EXCLUDE_FILE to the linker script language for further control over
 576   wildcard file names.
 577
 578 * Added -O option to optimize linker output (as of this writing, this only
 579   affects ELF shared library generation).
 580
 581 * The -e option now accepts a number as well as a symbol name.
 582
 583 * Added --no-undefined option to disallow undefined symbols when creating a
 584   shared library.
 585
 586 * The linker now issues a warning, not an error, for an undefined symbol when
 587   using -Bsymbolic; use the new --no-undefined option to get the old
 588   behaviour.
 589
 590 * Added --demangle and --no-demangle options.
 591
 592 Changes in version 2.9:
 593
 594 * Added SQUAD to the linker script language.
 595
 596 * New option --no-warn-mismatch.
 597
 598 * The MEMORY command now parses the attributes to determine where sections that
 599   are not placed in a specific memory region are placed.
 600
 601 Changes in version 2.8:
 602
 603 * Linker scripts may now contain shell wildcard characters for file and section
 604   names.
 605
 606 * The linker now supports symbol versions in ELF.
 607
 608 * The NOCROSSREFS command was added to the linker script language.
 609
 610 * The LOADADDR expression was added to the linker script language.
 611
 612 * MAX and MIN functions were added to the linker script language.
 613
 614 * The OVERLAY construct was added to the linker script language.
 615
 616 * New option --warn-section-align to warn when the address of an output section
 617   changes due to alignment of an input section.
 618
 619 * New options --filter/-F and --auxiliary/-f.
 620
 621 Changes in version 2.7:
 622
 623 * New option --cref to print out a cross reference table.
 624
 625 * New option --wrap SYMBOL.
 626
 627 * New option --no-whole-archive, to turn off the effect of --whole-archive.
 628
 629 * Input sections assigned to the output section /DISCARD/ in the linker script
 630   are not included in the output file.
 631
 632 * The SunOS and ELF linkers now merge stabs debugging information which uses
 633   the N_BINCL and N_EINCL stab types.  This reduces the amount of debugging
 634   information generated.
 635
 636 Changes in version 2.6:
 637
 638 * When an ELF section name is representable as a C identifier (this is not true
 639 of most ELF section names), the linker will automatically define symbols
 640 __start_SECNAME and __stop_SECNAME, where SECNAME is the section name, at the
 641 beginning and the end of the section.  This is used by glibc.
 642
 643   Addendum: Current versions of the linker (at least for version 2.18 onwards
 644 and possibly much earlier as well) place two restrictions on this feature:  The
 645 symbols are only implemented for orphaned sections, not for explicitly placed
 646 sections and they are PROVIDEd rather than being defined.
 647
 648 * When an ELF section named .gnu.warning is encountered in an input file, the
 649 contents of the section are displayed as an error message, and the section is
 650 not copied into the output file.  This is used by glibc.
 651
 652 * When an ELF section named .gnu.warning.SYMBOL is encountered in an input
 653 file, and the symbol SYMBOL is referenced by some object file, the contents of
 654 the section are displayed as an error message.  The section is not copied into
 655 the output file, unless doing a relocatable or shared link.  This is used by
 656 glibc.
 657
 658 * New options -split-by-reloc and -split-by-file.
 659
 660 * The linker now supports linking PIC compiled code on SPARC SunOS.  It can
 661 also create SPARC SunOS shared libraries, and, like the native SunOS linker,
 662 will do so whenever there is an undefined symbol in the link and neither the -e
 663 nor the -r option was used.
 664
 665 * The -rpath option may be used on SunOS to set the list of directories to be
 666 searched at run time.  This overrides the default of building the list from the
 667 -L options.
 668
 669 * The COFF linker now combines debugging information for structs, unions, and
 670 enums, so that even if the same type is defined in multiple input files it will
 671 only be defined once in the output file.  The --traditional-format switch will
 672 prevent this optimization.
 673
 674 Changes in version 2.5:
 675
 676 * The linker now supports linking against SunOS shared libraries.  It still can
 677 not link SunOS PIC (Position Independent Code) files, so it can not be used to
 678 generate shared libraries.
 679
 680 * The linker now supports linking against ELF shared libraries for the i386
 681 (UnixWare) and SPARC (Solaris).  It can also link ELF PIC files, and can be
 682 used to generate shared libraries.  Shared library generation is not well
 683 tested; please report any problems encountered.  The linker is now enabled for
 684 Solaris again.
 685
 686 * Eric Youngdale has contributed Linux support code, including linking against
 687 Linux a.out shared libraries.  The linker produces Linux QMAGIC binaries.
 688
 689 * The ELF backend has been converted to the new linker code.  To use the new
 690 ELF linker, each particular target requires a relocation function.  So far,
 691 this function has been written for i386 (UnixWare), SPARC (Solaris) MIPS (Irix
 692 5), and HPPA ELF targets.
 693
 694 * The -( (--start-group) and -) (--end-group) options have been added to
 695 support searching a group of archives as though they were a single archive.
 696 This can also be used in a linker script, as GROUP ( files ).
 697
 698 * When a file is named on the command line, and the linker does not recognize
 699 it as an object file, the linker will now treat the file as a linker script
 700 file.  A linker script named in this way augments, but does not replace, the
 701 default linker script.
 702
 703 * The -warn-once option was added.  It causes the linker to only warn once per
 704 undefined symbol, rather than once per reference.
 705
 706 * The COFF backend has been converted to the new linker code.  As with ELF, to
 707 use the new linker, each particular target requires a relocation function.  So
 708 far, this function has been written for the i386, m68k, a29k and SH targets.
 709
 710 * The -V flag was made a synonym for -v, for SVR4 compatibility.  The old -V
 711 behaviour is available via --verbose.
 712
 713 Changes in version 2.4:
 714
 715 * New linker code, by Steve Chamberlain and Ian Taylor.  For a.out and ecoff
 716   formats (so far), this should result in considerable savings in time
 717   and memory used while linking; slightly poorer performance than
 718   before for formats not converted yet.
 719
 720 * Command-line parsing is no longer done with flex.  This means
 721   oddball characters in filenames won't get treated as argument
 722   separators.
 723
 724 * HP-PA ELF support, by Jeff Law.  (No SOM support yet.)
 725
 726 * Mach i386 support, by David Mackenzie.
 727
 728 * Irix 4 shared libraries are now supported (Irix 5 uses ELF, and ELF shared
 729   libraries are not yet supported).
 730
 731 * COFF shared libraries (as on SCO) should work as well.
 732
 733 * The linker is disabled for Solaris.  (Actually, it was in 2.3 also, I just
 734   forgot to note it.)  Some of their C library routines don't work when
 735   statically linked, and the GNU linker doesn't support dynamic linking yet.
 736
 737 Changes in version 2.3:
 738
 739 * Weak symbols are now supported.
 740
 741 * ELF support has been added.  The linker has been bootstrapped on
 742   UnixWare and Solaris.
 743
 744 * Alpha OSF/1 support has been added (non dynamic linking only).
 745
 746 Changes in version 2.2:
 747
 748 * The `bfd' library has been updated to reduce a.out-format string
 749   table size.  The effect of this is that files linked from many input
 750   files with duplicate symbols (`-g' debugging records, or identical
 751   static symbols) should be much smaller.
 752
 753 Changes in version 2.1:
 754
 755 * The ld -ySYMBOL flag (to trace references to SYMBOL) is now implemented.
 756
 757 * There is now support for writing ECOFF files, so ld and the
 758   other utilities should work on Risc/Ultrix and Irix.
 759
 760 \f
 761 Copyright (C) 2012-2019 Free Software Foundation, Inc.
 762
 763 Copying and distribution of this file, with or without modification,
 764 are permitted in any medium without royalty provided the copyright
 765 notice and this notice are preserved.
 766
 767 Local variables:
 768 fill-column: 79
 769 End: