ld/NEWS

   1 -*- text -*-
   2
   3 * Add --error-handling-script=<NAME> command line option to allow a helper
   4   script to be invoked when an undefined symbol or a missing library is
   5   encountered.  This option can be suppressed via the configure time
   6   switch: --enable-error-handling-script=no.
   7
   8 * Add -z x86-64-{baseline|v[234]} to the x86 ELF linker to mark
   9   x86-64-{baseline|v[234]} ISA level as needed.
  10
  11 * Add -z unique-symbol to avoid duplicated local symbol names.
  12
  13 * The creation of PE format DLLs now defaults to using a more secure set of DLL
  14   characteristics.
  15
  16 * The linker now deduplicates the types in .ctf sections.  The new
  17   command-line option --ctf-share-types describes how to do this:
  18   its default value, share-unconflicted, produces the most compact
  19   output.
  20
  21 * The linker now omits the "variable section" from .ctf sections by
  22   default, saving space.  This is almost certainly what you want
  23   unless you are working on a project that has its own analogue
  24   of symbol tables that are not reflected in the ELF symtabs.
  25
  26 * Add support for the SHF_GNU_RETAIN ELF section flag.
  27   This flag specifies that the section should not be garbage collected by the
  28   linker.
  29
  30 Changes in 2.35:
  31
  32 * X86 NaCl target support is removed.
  33
  34 * Add ELF linker command-line options, --export-dynamic-symbol and
  35   --export-dynamic-symbol-list, to make symbols dynamic.
  36
  37 * Add a configure option, --enable-textrel-check=[no|yes|warning|error],
  38   to decide what ELF linker should do by default with DT_TEXTREL in an
  39   executable or shared library.  Default to yes for Linux/x86 targets.
  40
  41 * The -Map=<filename> command line option has been extended so that if
  42   <filename> is a directory then <filename>/<output-filename>.map will be
  43   created.
  44
  45 * Add a command-line option for ELF linker, --warn-textrel, to warn that
  46   DT_TEXTREL is set in a position-independent executable or shared object.
  47
  48 * Add command-line options --enable-non-contiguous-regions and
  49   --enable-non-contiguous-regions-warnings.
  50
  51 * Add command-line option --imagic for the pdp11-aout target to output format
  52   IMAGIC (0411) for separate instruction and data spaces, and change the
  53   default format option for pdp11-aout to be --omagic.
  54
  55 * Relative pathnames in INPUT() and GROUP() directives in linker scripts are
  56   searched relative to the directory of the linker script before other search
  57   paths.
  58
  59 * Add ELF linker command-line option `-z start-stop-visibility=...' to control
  60   the visibility of synthetic `__start_SECNAME` and `__stop_SECNAME` symbols.
  61
  62 * Add command-line option --dependency-file to write a Make-style dependency
  63   file listing the input files consulted by the linker, like the files written
  64   by the compiler's -M -MP options.
  65
  66 Changes in 2.34:
  67
  68 * The ld check for "PHDR segment not covered by LOAD segment" is more
  69   effective, catching cases that were wrongly allowed by previous versions of
  70   ld.  If you see this error it is likely you are linking with a bad linker
  71   script or the binary you are building is not intended to be loaded by a
  72   dynamic loader.  In the latter case --no-dynamic-linker is appropriate.
  73
  74 * cr16c support removed.
  75
  76 * Add support for z80-elf.
  77
  78 * Add support for relocation of each byte or word of multibyte value to Z80
  79   targets.
  80
  81 * Add support for Zilog eZ80 (both ADL and Z80 mode) and Zilog Z180 CPUs.
  82
  83 Changes in 2.33:
  84
  85 * Add command-line option --no-print-map-discarded.
  86
  87 * The Cortex-A53 Erratum 843419 workaround now supports a choice of which
  88   workaround to use.  The option --fix-cortex-a53-843419 now takes an
  89   optional argument --fix-cortex-a53-843419[=full|adr|adrp] which can be
  90   used to force a particular workaround to be used.  See --help for AArch64
  91   for more details.
  92
  93 * Add target handlers for AArch64 for ELF GNU program properties.
  94
  95 * Add support for GNU_PROPERTY_AARCH64_FEATURE_1_BTI in ELF GNU program
  96   properties in the AArch64 ELF linker.
  97
  98 * Add support for GNU_PROPERTY_AARCH64_FEATURE_1_PAC in ELF GNU program
  99   properties in the AArch64 ELF linker.
 100
 101 * Add -z force-bti for AArch64 to enable GNU_PROPERTY_AARCH64_FEATURE_1_BTI
 102   on output while warning about missing GNU_PROPERTY_AARCH64_FEATURE_1_BTI
 103   on inputs and use PLTs protected with BTI.
 104
 105 * Add -z pac-plt for AArch64 to pick PAC enabled PLTs.
 106
 107 Changes in 2.32:
 108
 109 * Report property change in linker map file when merging GNU properties.
 110
 111 * Add support for the C-SKY processor series.
 112
 113 * -t now doesn't report members within archives, unless -t is given twice.
 114   A single -t is now more useful when generating a list of files that should be
 115   packaged for a linker bug report.  For example:
 116     gcc hello.c -save-temps -Wl,-t | xargs realpath | sort | uniq > files
 117     tar cJf test.tar.xz `cat files`
 118
 119 Changes in 2.31:
 120
 121 * Speed up direct linking with DLLs for Cygwin and Mingw targets.
 122
 123 * Add a configure option --enable-separate-code to decide whether
 124   -z separate-code should be enabled in ELF linker by default.  Default
 125   to yes for Linux/x86 targets.  Note that -z separate-code can increase
 126   disk and memory size.
 127
 128 Changes in 2.30:
 129
 130 * Add -z separate-code to generate separate code PT_LOAD segment.
 131
 132 * Add "-z undefs" command-line option as the inverse of the "-z defs" option.
 133
 134 * Add -z globalaudit command-line option to force audit libraries to be run
 135   for every dynamic object loaded by an executable - provided that the loader
 136   supports this functionality.
 137
 138 * Tighten linker script grammar around file name specifiers to prevent the use
 139   of SORT_BY_ALIGNMENT and SORT_BY_INIT_PRIORITY on filenames.  These would
 140   previously be accepted but had no effect.
 141
 142 * The EXCLUDE_FILE directive can now be placed within any SORT_* directive
 143   within input section lists.
 144
 145 Changes in 2.29:
 146
 147 * Support for -z shstk in the x86 ELF linker to generate
 148   GNU_PROPERTY_X86_FEATURE_1_SHSTK in ELF GNU program properties.
 149
 150 * Add support for GNU_PROPERTY_X86_FEATURE_1_SHSTK in ELF GNU program
 151   properties in the x86 ELF linker.
 152
 153 * Add support for GNU_PROPERTY_X86_FEATURE_1_IBT in ELF GNU program
 154   properties in the x86 ELF linker.
 155
 156 * Support for -z ibtplt in the x86 ELF linker to generate IBT-enabled
 157   PLT.
 158
 159 * Support for -z ibt in the x86 ELF linker to generate IBT-enabled
 160   PLT as well as GNU_PROPERTY_X86_FEATURE_1_IBT in ELF GNU program
 161   properties.
 162
 163 * Add support for ELF SHF_GNU_MBIND and PT_GNU_MBIND_XXX.
 164
 165 * Add support for ELF GNU program properties.
 166
 167 * Add support for the Texas Instruments PRU processor.
 168
 169 * When configuring for arc*-*-linux* targets the default linker emulation will
 170   change if --with-cpu=nps400 is used at configure time.
 171
 172 * Improve assignment of LMAs to orphan sections in some edge cases where a
 173   mixture of both AT>LMA_REGION and AT(LMA) are used.
 174
 175 * Orphan sections placed after an empty section that has an AT(LMA) will now
 176   take an load memory address starting from LMA.
 177
 178 * Section groups can now be resolved (the group deleted and the group members
 179   placed like normal sections) at partial link time either using the new linker
 180   option --force-group-allocation or by placing FORCE_GROUP_ALLOCATION into the
 181   linker script.
 182
 183 Changes in 2.28:
 184
 185 * The EXCLUDE_FILE linker script construct can now be applied outside of the
 186   section list in order for the exclusions to apply over all input sections in
 187   the list.
 188
 189 * Add support for the RISC-V architecture.
 190
 191 * The command-line option --no-eh-frame-hdr can now be used in ELF based
 192   linkers to disable the automatic generation of .eh_frame_hdr sections.
 193
 194 * Add --in-implib=<infile> to the ARM linker to enable specifying a set of
 195   Secure Gateway veneers that must exist in the output import library specified
 196   by --out-implib=<outfile> and the address they must have.  As such,
 197   --in-implib is only supported in combination with --cmse-implib.
 198
 199 * Extended the --out-implib=<file> option, previously restricted to x86 PE
 200   targets, to any ELF based target.  This allows the generation of an import
 201   library for an ELF executable, which can then be used by another application
 202   to link against the executable.
 203
 204 Changes in 2.27:
 205
 206 * Add a configure option --enable-relro to decide whether -z relro should
 207   be enabled in ELF linker by default.  Default to yes for all Linux
 208   targets except FRV, HPPA, IA64 and MIPS.  Note that -z relro can increase
 209   disk and memory size.
 210
 211 * Support for -z noreloc-overflow in the x86-64 ELF linker to disable
 212   relocation overflow check.
 213
 214 * Add -z common/-z nocommon options for ELF targets to control whether to
 215   convert common symbols to the STT_COMMON type during a relocatable link.
 216
 217 * Support for -z nodynamic-undefined-weak in the x86 ELF linker, which
 218   avoids dynamic relocations against undefined weak symbols in executable.
 219
 220 * The NOCROSSREFSTO command was added to the linker script language.
 221
 222 * Add --no-apply-dynamic-relocs to the AArch64 linker to do not apply link-time
 223   values for dynamic relocations.
 224
 225 Changes in 2.26:
 226
 227 * Add --fix-stm32l4xx-629360 to the ARM linker to enable a link-time
 228   workaround for a bug in the bus matrix / memory controller for some of
 229   the STM32 Cortex-M4 based products (STM32L4xx)
 230
 231 * Add a configure option --enable-compressed-debug-sections={all,ld} to
 232   decide whether DWARF debug sections should be compressed by default.
 233
 234 * Add support for the ARC EM/HS, and ARC600/700 architectures.
 235
 236 * Experimental support for linker garbage collection (--gc-sections)
 237   has been enabled for COFF and PE based targets.
 238
 239 * New command-line option for ELF targets to compress DWARF debug
 240   sections, --compress-debug-sections=[none|zlib|zlib-gnu|zlib-gabi].
 241
 242 * New command-line option, --orphan-handling=[place|warn|error|discard], to
 243   adjust how orphan sections are handled.  The default is 'place' which gives
 244   the current behaviour, 'warn' and 'error' issue a warning or error
 245   respectively when orphan sections are found, and 'discard' will discard all
 246   orphan sections.
 247
 248 * Add support for LLVM plugin.
 249
 250 * Add --print-memory-usage option to report memory blocks usage.
 251
 252 * Add --require-defined option, it's like --undefined except the new symbol
 253   must be defined by the end of the link.
 254
 255 Changes in 2.25:
 256
 257 * PE binaries now once again contain real timestamps by default.  To disable
 258   the inclusion of a timestamp in a PE binary, use the --no-insert-timestamp
 259   command-line option.
 260
 261 * Replace support for openrisc and or32 with support for or1k.
 262
 263 * Add support for the --build-id command-line option to COFF based targets.
 264
 265 * x86/x86_64 pe-coff now supports the --build-id option.
 266
 267 * Add support for the Andes NDS32.
 268
 269 Changes in 2.24:
 270
 271 * Add LOG2CEIL() builtin function to the linker script language
 272
 273 * Add support for the Texas Instruments MSP430X processor.
 274
 275 * Add support for Altera Nios II.
 276
 277 * Add support for the V850E3V5 architecture.
 278
 279 * Add support for the Imagination Technologies Meta processor.
 280
 281 * --enable-new-dtags no longer generates old dtags in addition to new dtags.
 282
 283 * Remove linker support for MIPS ECOFF targets.
 284
 285 * Add ALIGN_WITH_INPUT to the linker script language to force the alignment of
 286   an output section to use the maximum alignment of all its input sections.
 287
 288 Changes in 2.23:
 289
 290 * Enable compressed debug section feature for x86/x86_64 pe-coff.
 291
 292 * Add support for the 64-bit ARM architecture: AArch64.
 293
 294 * Added SORT_NONE to the linker script language to disable section sorting.
 295
 296 * Add a linker-provided symbol when producing ELF output, '__ehdr_start'
 297   to point to the ELF file header (and nearby program headers) in the
 298   program's memory image.
 299
 300 * Add support for S12X processor.
 301
 302 * Add support for the VLE extension to the PowerPC architecture.
 303
 304 * Add support for the Freescale XGATE architecture.
 305
 306 * Add option -f FILE on AIX (for response file).
 307
 308 * Add support for the Renesas RL78 architecture.
 309
 310 * Add support for the Adapteva EPIPHANY architecture.
 311
 312 Changes in 2.22:
 313
 314 * --copy-dt-needed-entries is no longer enabled by default.  Instead
 315   --no-copy-dt-needed-entries is the default.
 316
 317 * INPUT_SECTION_FLAGS has been added to the linker script language
 318   to allow selection of input sections by section header section flags.
 319
 320 * Add support for the Tilera TILEPro and TILE-Gx architectures.
 321
 322 * Added SORT_BY_INIT_PRIORITY to the linker script language to permit
 323   sorting sections by numerical value of the GCC init_priority attribute
 324   encoded in the section name.
 325
 326 Changes in 2.21:
 327
 328 * Linker script expression evaluation is somewhat more sane.  This may
 329   break scripts that depend on quirks of the old expression evaluation.
 330
 331 * Turn off underscoring for x86_64 PE+-COFF targets.  For old behavior the
 332   option --enable-leading-mingw64-underscores can be used on configure of
 333   bfd.
 334
 335 * Add support for the TMS320C6000 (TI C6X) processor family.
 336
 337 * --add-needed renamed to --copy-dt-needed-entries in order to avoid confusion
 338   with --as-needed option.
 339
 340 * Extend .def file syntax by '== <ID>' for imports and exports. This allows
 341   to alias the import/export table name written in PE image.
 342
 343 * Add --exclude-all-symbols option to PE based linkers.  This prevents all
 344   symbols from automatically being exported.
 345
 346 * Add support for the Renesas RX processor.
 347
 348 * Add support for alpha-vms target.
 349
 350 Changes in 2.20:
 351
 352 * GNU/Linux targets now support the STB_GNU_UNIQUE symbol binding.  This is a
 353   GNU extension to the standard set of ELF symbol bindings.  The binding will
 354   be passed on to the dynamic linker which will make sure that in the entire
 355   process there is just one symbol with the given name and type in use.
 356
 357 * PE targets now support a GNU extension to allow the alignment of common
 358   common symbols to be specified.  This support uses custom options in
 359   the .drectve section, which will be disregarded by the native tools.
 360
 361 * PE targets now add primitive support for ELF version scripts; symbols
 362   are not versioned, but the local and global symbol visibility directives
 363   are respected when filtering symbols in auto-export mode.
 364
 365 * New option --no-export-dynamic to undo the effect of the -E and
 366   --export-dynamic options.
 367
 368 * ELF: --warn-alternate-em option to warn if an object has alternate
 369   ELF machine code.
 370
 371 * New script function REGION_ALIAS to add alias names to memory regions.
 372
 373 * PE targets no longer make use of the long section names PE extension to
 374   the COFF format when generating executable images, by default.  The old
 375   (slightly non-conformant) behaviour can still be invoked by using the
 376   new '--enable-long-section-names' command-line option.  It is also enabled
 377   automatically in the presence of un-stripped debug information, as GDB
 378   needs to be able to find the debug info sections by their full names.
 379
 380 * For GNU/Linux systems the linker will now avoid processing any relocations
 381   made against symbols of the STT_GNU_IFUNC type and instead emit them into
 382   the resulting binary for processing by the loader.
 383
 384 * --as-needed now links in a dynamic library if it satisfies undefined
 385   symbols in regular objects, or in other dynamic libraries.  In the
 386   latter case the library is not linked if it is found in a DT_NEEDED
 387   entry of one of the libraries already linked.
 388
 389 * Add a new command-line option, -Ttext-segment ADDR, for ELF targets
 390   to set the address of the first byte of the text segment.
 391
 392 * Add support for Sunplus score architecture.
 393
 394 * Add new option --use-nul-prefixed-import-tables to ld for PE targets to
 395   allow fallback to old import table generation with null element prefix.
 396
 397 * Windows PE systems now support a new --exclude-modules-for-implib option,
 398   allowing users to partition object files and archive members between a DLL
 399   and its associated import library as they are generated during linking.
 400
 401 * Add support for Lattice Mico32 (lm32) architecture.
 402
 403 * Add CR16 ELF --embedded-relocs (used to embedded relocations into binaries
 404   for Embedded-PIC code) option.
 405
 406 * Add to the PE/PE+ targets the support of two different kinds of
 407   pseudo-relocations.  They can be selected by the switches
 408   --enable-runtime-pseudo-reloc-v1 and --enable-runtime-pseudo-reloc-v2.
 409   For the switch --enable-runtime-pseudo-reloc it uses for 32-bit
 410   runtime pseudo relocation version one, for 64-bit the version two.
 411
 412 Changes in 2.19:
 413
 414 * Linker scripts support a new INSERT command that makes it easier to
 415   augment the default script.
 416
 417 * Linker script input section filespecs may now specify a file within an
 418   archive by writing "archive:file".
 419
 420 * The --sort-common switch now has an optional argument which specifies the
 421   direction of sorting.
 422
 423 * The M68K linker now supports multiple GOT generation schemes controlled via
 424   the --got=<type> command-line option.
 425
 426 * The ARM EABI linker will now generate stubs for function calls to symbols
 427   that are too far away.  The placement of the stubs is controlled by a new
 428   linker command-line option: --stub-group-size=N.
 429
 430 Changes in 2.18:
 431
 432 * Linker sources now released under version 3 of the GNU General Public
 433   License.
 434
 435 * ELF: New --build-id option to generate a unique per-binary identifier
 436   embedded in a note section.
 437
 438 * Added support for National Semicondutor CompactRISC (ie CR16) target.
 439
 440 * -l:foo now searches the library path for a filename called foo,
 441   without converting it to libfoo.a or libfoo.so.
 442
 443 * Add a new command-line option '--default-script=FILE' or '-dT FILE'
 444   which specifies a replacement for the built in, default linker
 445   script.
 446
 447 * ELF: Add -Bsymbolic-functions, --dynamic-list-cpp-new, which puts C++
 448   operator new and delete on the dynamic list, and --dynamic-list-data,
 449   builtin list for --dynamic-list, which puts global data symbols on the
 450   dynamic list.
 451
 452 * Add support for x86_64 PE+ target.
 453
 454 * Add support for Score target.
 455
 456 * ELF: Add --dynamic-list option to specify a list of global symbols
 457   whose references shouldn't be bound to the definition within the
 458   shared library, or a list of symbols which should be added to the
 459   symbol table in the executable.
 460
 461 * The default output section LMA has changed for allocatable sections from
 462   being equal to VMA, to keeping the difference between LMA and VMA the same as
 463   the previous output section in the same region.  This is a more useful
 464   default when using overlays and other cases where you specify an LMA
 465   differing from the VMA for some sections.
 466
 467 * New switch: --print-gc-sections to list any sections removed by garabge
 468   collection.
 469
 470 * ARM: Added --vfp11-denorm-fix option to work around an erratum in current
 471   VFP11 coprocessors.
 472
 473 Changes in 2.17:
 474
 475 * Support for the Infineon XC16X has been added by KPIT Cummins Infosystems.
 476
 477 * Modify the Linux linker search order to better match ld.so search order.
 478   Look for DT_NEEDED libraries in paths specified by ld.so.conf before
 479   searching the default directories, rather than vice versa.
 480   Use $prefix/etc/ld.so.conf if it exists, otherwise /etc/ld.so.conf.
 481
 482 * PE-COFF: Forward exports from DLL's can now be specified in .def files
 483   passed directly to ld.
 484
 485 * Support for the Z80 processor family has been added.
 486
 487 * Add support for the "@<file>" syntax to the command line, so that extra
 488   switches can be read from <file>.
 489
 490 Changes in 2.16:
 491
 492 * Support for the R_ARM_V4BX relocation as defined in the ARM AAELF
 493   specification has been added via the --fix-v4bx command-line option.
 494
 495 * New linker script construct AS_NEEDED(), which sets the --as-needed flag
 496   for input files listed inside of it.
 497
 498 * A new command-line option, --sysroot, can be used to override the
 499   default sysroot location.  It only applies to toolchains that were
 500   configured using --with-sysroot.
 501
 502 * New linker script functions: ORIGIN() and LENGTH() which return information
 503   about a specified memory region.
 504
 505 * Port to MAXQ processor contributed by HCL Tech.
 506
 507 * Added SEGMENT_START to the linker script language to permit the user to
 508   override the base address for a segment from the command-line.
 509
 510 * ELF: --warn-shared-textrel option to warn if adding a DT_TEXTREL to a shared
 511   object.
 512
 513 * Added SORT_BY_NAME and SORT_BY_ALIGNMENT to the linker script
 514   language to permit sorting sections by section name or section
 515   maximum alignment.
 516
 517 * Added a new linker command-line switch, --sort-section name|alignment,
 518   to sort sections by section name or maximum alignment.
 519
 520 * ELF: --add-needed/--no-add-needed options to control if a DT_NEEDED tag
 521   should be added when a shared library comes from DT_NEEDED tags.
 522
 523 * Support for the crx-elf target added.
 524
 525 * Support for the sh-symbianelf target added.
 526
 527 * A new linker command-line switch has been added which allows the hash table
 528   size to be set to a suitable prime value near to its argument.  This switch
 529   is --hash-size=<NUMBER>.  Also if the switch --reduce-memory-overheads is
 530   used, and --hash-size has not been used, then the default value will be set
 531   to 1021.
 532
 533 * Linker map files are now generated with an O(N) algorithm for finding symbols
 534   that are defined in each section.  This uses about 40% more memory for
 535   symbols than the old O(N^2) algorithm.  You can use the new
 536   --reduce-memory-overheads option to select the old algorithm; this option
 537   might also be used in the future to select similar tradeoffs.
 538
 539 Changes in 2.15:
 540
 541 * ELF: --as-needed/--no-as-needed options to control if a DT_NEEDED tag should
 542   be added only when a shared library is referenced.
 543
 544 * PE: --large-address-aware option to indicate executables support virtual
 545   addresses greater than 2 gigabytes.
 546
 547 * DWARF 2 support for i386pe added.
 548
 549 * The linker script operator DEFINED() will now yield 1 only for a symbol that
 550   is defined before the statement where DEFINED is used.
 551
 552 * The MIPS --embedded-relocs (used to embed relocations into binaries for
 553   Embedded-PIC code) is deprecated and will be removed in a future release.
 554
 555 * cr16c support added by NSC.
 556
 557 * m32r Linux (ELF) support added by Renesas.
 558
 559 * Improved linker's handling of unresolved symbols.  The switch
 560   --unresolved-symbols=<method> has been added to tell the linker when it
 561   should report them and the switch --warn-unresolved-symbols has been added to
 562   make reports be issued as warning messages rather than errors.
 563
 564 Changes in 2.14:
 565
 566 * Added support for Xtensa architecture.
 567
 568 * Added --with-sysroot configure switch to specify a target system root, for
 569   linking against a target filesystem image.
 570
 571 * Added --accept-unknown-linker-format to restore old linker behaviour (pre
 572   2.14) of silently accepting and linking in any files in an unknown binary
 573   file format.
 574
 575 * Added --no-omagic to undo the effects of the -N option.
 576
 577 * Support for Texas Instruments TMS320C4x and TMS320C3x series of
 578   DSP's contributed by Michael Hayes and Svein E. Seldal.
 579
 580 * Added --with-lib-path configure switch to specify default value for
 581   LIB_PATH.
 582
 583 * ARM port to QNX operating system added by Graeme Peterson.
 584
 585 * IP2K support added by Denis Chertykov.
 586
 587 Changes in 2.13:
 588
 589 * Support for the Fujitsu FRV architecture added by Red Hat. Models for FR400
 590   and FR500 included.
 591
 592 Changes in version 2.13:
 593
 594 * DEC VAX ELF support, by Matt Thomas.
 595
 596 Changes in version 2.12:
 597
 598 * Support for Don Knuth's MMIX, by Hans-Peter Nilsson.
 599
 600 * Support for the OpenRISC 32-bit embedded processor by OpenCores.
 601
 602 * Support for -z nocopyreloc in the x86 ELF linker, which disables
 603   production of copy relocs.  Warning: using this option may result in
 604   non-sharable applications.
 605
 606 * Support for -z combreloc in the ELF linker, which puts dynamic
 607   relocations against the same symbol together, so that dynamic linker
 608   can use an one-entry symbol lookup cache.
 609
 610 * Support for ELF SHF_MERGE section merging, by Jakub Jelinek.
 611
 612 Changes in version 2.11:
 613
 614 * Support for AMD x86-64 architecture, by Jan Hubicka, SuSE Labs.
 615
 616 * Support added for eliminating duplicate DWARF2 debug information by
 617   having the compiler generate the information in sections called
 618   .gnu.linkonce.wi.XXXX where XXXX is a checksum for the contents.  The
 619   linker then merges these sections together into the normal .debug_info
 620   section.
 621
 622 * The native ELF linker now searches the directories in DT_RUNPATH or
 623   DT_RPATH of a shared library for shared libraries needed by it.
 624
 625 * TI C54x support, by Timothy Wall.
 626
 627 * Added command-line switch --section-start to set the start address of any
 628   specified section.
 629
 630 * Added ability to emit full relocation information in linked executables,
 631   enabled by --emit-relocs.  Some post-linkage optimization tools need
 632   this information in order to be able to correctly identify and perform
 633   symbol relative addressing in the event of changes in section contents
 634   (instructions being added or deleted, extending data sections, etc.)
 635
 636 * Support for i860, by Jason Eckhardt (preliminary, alpha quality).
 637
 638 * Support for CRIS (Axis Communications ETRAX series).
 639
 640 * Support for PDP-11 and 2.11BSD a.out format, by Lars Brinkhoff.
 641
 642 Changes in version 2.10:
 643
 644 * Added AT> to the linker script language to allow load-time allocation of
 645   sections into regions.
 646
 647 * Added garbage collection of unused sections, enabled by --gc-sections.
 648   It does require a bit of backend support; currently implemented are
 649   arm-elf, avr-elf, d10v-elf, fr30-elf, i386-elf, m32r-elf, m68k-elf,
 650   mcore-elf, mips-elf, mn10300-elf, ppc-elf, sh-elf, sparc-elf, and v850-elf.
 651   Others will ignore the option.
 652
 653 * Added SORT to the linker script language to permit sorting sections by file
 654   name or section name.
 655
 656 * Added EXTERN to the linker script language as an equivalent to the -u
 657   command-line option.
 658
 659 * Added ASSERT to the linker script language.
 660
 661 * Added EXCLUDE_FILE to the linker script language for further control over
 662   wildcard file names.
 663
 664 * Added -O option to optimize linker output (as of this writing, this only
 665   affects ELF shared library generation).
 666
 667 * The -e option now accepts a number as well as a symbol name.
 668
 669 * Added --no-undefined option to disallow undefined symbols when creating a
 670   shared library.
 671
 672 * The linker now issues a warning, not an error, for an undefined symbol when
 673   using -Bsymbolic; use the new --no-undefined option to get the old
 674   behaviour.
 675
 676 * Added --demangle and --no-demangle options.
 677
 678 Changes in version 2.9:
 679
 680 * Added SQUAD to the linker script language.
 681
 682 * New option --no-warn-mismatch.
 683
 684 * The MEMORY command now parses the attributes to determine where sections that
 685   are not placed in a specific memory region are placed.
 686
 687 Changes in version 2.8:
 688
 689 * Linker scripts may now contain shell wildcard characters for file and section
 690   names.
 691
 692 * The linker now supports symbol versions in ELF.
 693
 694 * The NOCROSSREFS command was added to the linker script language.
 695
 696 * The LOADADDR expression was added to the linker script language.
 697
 698 * MAX and MIN functions were added to the linker script language.
 699
 700 * The OVERLAY construct was added to the linker script language.
 701
 702 * New option --warn-section-align to warn when the address of an output section
 703   changes due to alignment of an input section.
 704
 705 * New options --filter/-F and --auxiliary/-f.
 706
 707 Changes in version 2.7:
 708
 709 * New option --cref to print out a cross reference table.
 710
 711 * New option --wrap SYMBOL.
 712
 713 * New option --no-whole-archive, to turn off the effect of --whole-archive.
 714
 715 * Input sections assigned to the output section /DISCARD/ in the linker script
 716   are not included in the output file.
 717
 718 * The SunOS and ELF linkers now merge stabs debugging information which uses
 719   the N_BINCL and N_EINCL stab types.  This reduces the amount of debugging
 720   information generated.
 721
 722 Changes in version 2.6:
 723
 724 * When an ELF section name is representable as a C identifier (this is not true
 725 of most ELF section names), the linker will automatically define symbols
 726 __start_SECNAME and __stop_SECNAME, where SECNAME is the section name, at the
 727 beginning and the end of the section.  This is used by glibc.
 728
 729   Addendum: Current versions of the linker (at least for version 2.18 onwards
 730 and possibly much earlier as well) place two restrictions on this feature:  The
 731 symbols are only implemented for orphaned sections, not for explicitly placed
 732 sections and they are PROVIDEd rather than being defined.
 733
 734 * When an ELF section named .gnu.warning is encountered in an input file, the
 735 contents of the section are displayed as an error message, and the section is
 736 not copied into the output file.  This is used by glibc.
 737
 738 * When an ELF section named .gnu.warning.SYMBOL is encountered in an input
 739 file, and the symbol SYMBOL is referenced by some object file, the contents of
 740 the section are displayed as an error message.  The section is not copied into
 741 the output file, unless doing a relocatable or shared link.  This is used by
 742 glibc.
 743
 744 * New options -split-by-reloc and -split-by-file.
 745
 746 * The linker now supports linking PIC compiled code on SPARC SunOS.  It can
 747 also create SPARC SunOS shared libraries, and, like the native SunOS linker,
 748 will do so whenever there is an undefined symbol in the link and neither the -e
 749 nor the -r option was used.
 750
 751 * The -rpath option may be used on SunOS to set the list of directories to be
 752 searched at run time.  This overrides the default of building the list from the
 753 -L options.
 754
 755 * The COFF linker now combines debugging information for structs, unions, and
 756 enums, so that even if the same type is defined in multiple input files it will
 757 only be defined once in the output file.  The --traditional-format switch will
 758 prevent this optimization.
 759
 760 Changes in version 2.5:
 761
 762 * The linker now supports linking against SunOS shared libraries.  It still can
 763 not link SunOS PIC (Position Independent Code) files, so it can not be used to
 764 generate shared libraries.
 765
 766 * The linker now supports linking against ELF shared libraries for the i386
 767 (UnixWare) and SPARC (Solaris).  It can also link ELF PIC files, and can be
 768 used to generate shared libraries.  Shared library generation is not well
 769 tested; please report any problems encountered.  The linker is now enabled for
 770 Solaris again.
 771
 772 * Eric Youngdale has contributed Linux support code, including linking against
 773 Linux a.out shared libraries.  The linker produces Linux QMAGIC binaries.
 774
 775 * The ELF backend has been converted to the new linker code.  To use the new
 776 ELF linker, each particular target requires a relocation function.  So far,
 777 this function has been written for i386 (UnixWare), SPARC (Solaris) MIPS (Irix
 778 5), and HPPA ELF targets.
 779
 780 * The -( (--start-group) and -) (--end-group) options have been added to
 781 support searching a group of archives as though they were a single archive.
 782 This can also be used in a linker script, as GROUP ( files ).
 783
 784 * When a file is named on the command line, and the linker does not recognize
 785 it as an object file, the linker will now treat the file as a linker script
 786 file.  A linker script named in this way augments, but does not replace, the
 787 default linker script.
 788
 789 * The -warn-once option was added.  It causes the linker to only warn once per
 790 undefined symbol, rather than once per reference.
 791
 792 * The COFF backend has been converted to the new linker code.  As with ELF, to
 793 use the new linker, each particular target requires a relocation function.  So
 794 far, this function has been written for the i386, m68k, a29k and SH targets.
 795
 796 * The -V flag was made a synonym for -v, for SVR4 compatibility.  The old -V
 797 behaviour is available via --verbose.
 798
 799 Changes in version 2.4:
 800
 801 * New linker code, by Steve Chamberlain and Ian Taylor.  For a.out and ecoff
 802   formats (so far), this should result in considerable savings in time
 803   and memory used while linking; slightly poorer performance than
 804   before for formats not converted yet.
 805
 806 * Command-line parsing is no longer done with flex.  This means
 807   oddball characters in filenames won't get treated as argument
 808   separators.
 809
 810 * HP-PA ELF support, by Jeff Law.  (No SOM support yet.)
 811
 812 * Mach i386 support, by David Mackenzie.
 813
 814 * Irix 4 shared libraries are now supported (Irix 5 uses ELF, and ELF shared
 815   libraries are not yet supported).
 816
 817 * COFF shared libraries (as on SCO) should work as well.
 818
 819 * The linker is disabled for Solaris.  (Actually, it was in 2.3 also, I just
 820   forgot to note it.)  Some of their C library routines don't work when
 821   statically linked, and the GNU linker doesn't support dynamic linking yet.
 822
 823 Changes in version 2.3:
 824
 825 * Weak symbols are now supported.
 826
 827 * ELF support has been added.  The linker has been bootstrapped on
 828   UnixWare and Solaris.
 829
 830 * Alpha OSF/1 support has been added (non dynamic linking only).
 831
 832 Changes in version 2.2:
 833
 834 * The `bfd' library has been updated to reduce a.out-format string
 835   table size.  The effect of this is that files linked from many input
 836   files with duplicate symbols (`-g' debugging records, or identical
 837   static symbols) should be much smaller.
 838
 839 Changes in version 2.1:
 840
 841 * The ld -ySYMBOL flag (to trace references to SYMBOL) is now implemented.
 842
 843 * There is now support for writing ECOFF files, so ld and the
 844   other utilities should work on Risc/Ultrix and Irix.
 845
 846 \f
 847 Copyright (C) 2012-2020 Free Software Foundation, Inc.
 848
 849 Copying and distribution of this file, with or without modification,
 850 are permitted in any medium without royalty provided the copyright
 851 notice and this notice are preserved.
 852
 853 Local variables:
 854 fill-column: 79
 855 End: