ld/NEWS

   1 -*- text -*-
   2
   3 * arm-symbianelf support removed.
   4
   5 * Add -z report-relative-reloc to x86 ELF linker to report dynamic
   6   relative relocations.
   7
   8 Changes in 2.36:
   9
  10 * Add libdep plugin, for linking dependencies of static libraries that
  11   were recorded by ar in the __.LIBDEP archive member.
  12
  13 * Add --error-handling-script=<NAME> command line option to allow a helper
  14   script to be invoked when an undefined symbol or a missing library is
  15   encountered.  This option can be suppressed via the configure time
  16   switch: --enable-error-handling-script=no.
  17
  18 * Add -z lam-u48 to x86-64 ELF linker to generate LAM_U48 property.
  19
  20 * Add -z lam-u57 to x86-64 ELF linker to enerate LAM_U57 property.
  21
  22 * Add -z lam-u48-report=[none|warning|error] to report missing LAM_U48
  23   property.
  24
  25 * Add -z lam-u57-report=[none|warning|error] to report missing LAM_U57
  26   property.
  27
  28 * Add -z lam-report=[none|warning|error] to report missing LAM_U48 and
  29   LAM_U57 properties.
  30
  31 * Add -z x86-64-{baseline|v[234]} to the x86 ELF linker to mark
  32   x86-64-{baseline|v[234]} ISA level as needed.
  33
  34 * Add -z unique-symbol to avoid duplicated local symbol names.
  35
  36 * The creation of PE format DLLs now defaults to using a more secure set of DLL
  37   characteristics.
  38
  39 * The linker now deduplicates the types in .ctf sections.  The new
  40   command-line option --ctf-share-types describes how to do this:
  41   its default value, share-unconflicted, produces the most compact
  42   output.
  43
  44 * The linker now omits the "variable section" from .ctf sections by
  45   default, saving space.  This is almost certainly what you want
  46   unless you are working on a project that has its own analogue
  47   of symbol tables that are not reflected in the ELF symtabs.
  48
  49 * Add support for the SHF_GNU_RETAIN ELF section flag.
  50   This flag specifies that the section should not be garbage collected by the
  51   linker.
  52
  53 Changes in 2.35:
  54
  55 * X86 NaCl target support is removed.
  56
  57 * Add ELF linker command-line options, --export-dynamic-symbol and
  58   --export-dynamic-symbol-list, to make symbols dynamic.
  59
  60 * Add a configure option, --enable-textrel-check=[no|yes|warning|error],
  61   to decide what ELF linker should do by default with DT_TEXTREL in an
  62   executable or shared library.  Default to yes for Linux/x86 targets.
  63
  64 * The -Map=<filename> command line option has been extended so that if
  65   <filename> is a directory then <filename>/<output-filename>.map will be
  66   created.
  67
  68 * Add a command-line option for ELF linker, --warn-textrel, to warn that
  69   DT_TEXTREL is set in a position-independent executable or shared object.
  70
  71 * Add command-line options --enable-non-contiguous-regions and
  72   --enable-non-contiguous-regions-warnings.
  73
  74 * Add command-line option --imagic for the pdp11-aout target to output format
  75   IMAGIC (0411) for separate instruction and data spaces, and change the
  76   default format option for pdp11-aout to be --omagic.
  77
  78 * Relative pathnames in INPUT() and GROUP() directives in linker scripts are
  79   searched relative to the directory of the linker script before other search
  80   paths.
  81
  82 * Add ELF linker command-line option `-z start-stop-visibility=...' to control
  83   the visibility of synthetic `__start_SECNAME` and `__stop_SECNAME` symbols.
  84
  85 * Add command-line option --dependency-file to write a Make-style dependency
  86   file listing the input files consulted by the linker, like the files written
  87   by the compiler's -M -MP options.
  88
  89 Changes in 2.34:
  90
  91 * The ld check for "PHDR segment not covered by LOAD segment" is more
  92   effective, catching cases that were wrongly allowed by previous versions of
  93   ld.  If you see this error it is likely you are linking with a bad linker
  94   script or the binary you are building is not intended to be loaded by a
  95   dynamic loader.  In the latter case --no-dynamic-linker is appropriate.
  96
  97 * cr16c support removed.
  98
  99 * Add support for z80-elf.
 100
 101 * Add support for relocation of each byte or word of multibyte value to Z80
 102   targets.
 103
 104 * Add support for Zilog eZ80 (both ADL and Z80 mode) and Zilog Z180 CPUs.
 105
 106 Changes in 2.33:
 107
 108 * Add command-line option --no-print-map-discarded.
 109
 110 * The Cortex-A53 Erratum 843419 workaround now supports a choice of which
 111   workaround to use.  The option --fix-cortex-a53-843419 now takes an
 112   optional argument --fix-cortex-a53-843419[=full|adr|adrp] which can be
 113   used to force a particular workaround to be used.  See --help for AArch64
 114   for more details.
 115
 116 * Add target handlers for AArch64 for ELF GNU program properties.
 117
 118 * Add support for GNU_PROPERTY_AARCH64_FEATURE_1_BTI in ELF GNU program
 119   properties in the AArch64 ELF linker.
 120
 121 * Add support for GNU_PROPERTY_AARCH64_FEATURE_1_PAC in ELF GNU program
 122   properties in the AArch64 ELF linker.
 123
 124 * Add -z force-bti for AArch64 to enable GNU_PROPERTY_AARCH64_FEATURE_1_BTI
 125   on output while warning about missing GNU_PROPERTY_AARCH64_FEATURE_1_BTI
 126   on inputs and use PLTs protected with BTI.
 127
 128 * Add -z pac-plt for AArch64 to pick PAC enabled PLTs.
 129
 130 Changes in 2.32:
 131
 132 * Report property change in linker map file when merging GNU properties.
 133
 134 * Add support for the C-SKY processor series.
 135
 136 * -t now doesn't report members within archives, unless -t is given twice.
 137   A single -t is now more useful when generating a list of files that should be
 138   packaged for a linker bug report.  For example:
 139     gcc hello.c -save-temps -Wl,-t | xargs realpath | sort | uniq > files
 140     tar cJf test.tar.xz `cat files`
 141
 142 Changes in 2.31:
 143
 144 * Speed up direct linking with DLLs for Cygwin and Mingw targets.
 145
 146 * Add a configure option --enable-separate-code to decide whether
 147   -z separate-code should be enabled in ELF linker by default.  Default
 148   to yes for Linux/x86 targets.  Note that -z separate-code can increase
 149   disk and memory size.
 150
 151 Changes in 2.30:
 152
 153 * Add -z separate-code to generate separate code PT_LOAD segment.
 154
 155 * Add "-z undefs" command-line option as the inverse of the "-z defs" option.
 156
 157 * Add -z globalaudit command-line option to force audit libraries to be run
 158   for every dynamic object loaded by an executable - provided that the loader
 159   supports this functionality.
 160
 161 * Tighten linker script grammar around file name specifiers to prevent the use
 162   of SORT_BY_ALIGNMENT and SORT_BY_INIT_PRIORITY on filenames.  These would
 163   previously be accepted but had no effect.
 164
 165 * The EXCLUDE_FILE directive can now be placed within any SORT_* directive
 166   within input section lists.
 167
 168 Changes in 2.29:
 169
 170 * Support for -z shstk in the x86 ELF linker to generate
 171   GNU_PROPERTY_X86_FEATURE_1_SHSTK in ELF GNU program properties.
 172
 173 * Add support for GNU_PROPERTY_X86_FEATURE_1_SHSTK in ELF GNU program
 174   properties in the x86 ELF linker.
 175
 176 * Add support for GNU_PROPERTY_X86_FEATURE_1_IBT in ELF GNU program
 177   properties in the x86 ELF linker.
 178
 179 * Support for -z ibtplt in the x86 ELF linker to generate IBT-enabled
 180   PLT.
 181
 182 * Support for -z ibt in the x86 ELF linker to generate IBT-enabled
 183   PLT as well as GNU_PROPERTY_X86_FEATURE_1_IBT in ELF GNU program
 184   properties.
 185
 186 * Add support for ELF SHF_GNU_MBIND and PT_GNU_MBIND_XXX.
 187
 188 * Add support for ELF GNU program properties.
 189
 190 * Add support for the Texas Instruments PRU processor.
 191
 192 * When configuring for arc*-*-linux* targets the default linker emulation will
 193   change if --with-cpu=nps400 is used at configure time.
 194
 195 * Improve assignment of LMAs to orphan sections in some edge cases where a
 196   mixture of both AT>LMA_REGION and AT(LMA) are used.
 197
 198 * Orphan sections placed after an empty section that has an AT(LMA) will now
 199   take an load memory address starting from LMA.
 200
 201 * Section groups can now be resolved (the group deleted and the group members
 202   placed like normal sections) at partial link time either using the new linker
 203   option --force-group-allocation or by placing FORCE_GROUP_ALLOCATION into the
 204   linker script.
 205
 206 Changes in 2.28:
 207
 208 * The EXCLUDE_FILE linker script construct can now be applied outside of the
 209   section list in order for the exclusions to apply over all input sections in
 210   the list.
 211
 212 * Add support for the RISC-V architecture.
 213
 214 * The command-line option --no-eh-frame-hdr can now be used in ELF based
 215   linkers to disable the automatic generation of .eh_frame_hdr sections.
 216
 217 * Add --in-implib=<infile> to the ARM linker to enable specifying a set of
 218   Secure Gateway veneers that must exist in the output import library specified
 219   by --out-implib=<outfile> and the address they must have.  As such,
 220   --in-implib is only supported in combination with --cmse-implib.
 221
 222 * Extended the --out-implib=<file> option, previously restricted to x86 PE
 223   targets, to any ELF based target.  This allows the generation of an import
 224   library for an ELF executable, which can then be used by another application
 225   to link against the executable.
 226
 227 Changes in 2.27:
 228
 229 * Add a configure option --enable-relro to decide whether -z relro should
 230   be enabled in ELF linker by default.  Default to yes for all Linux
 231   targets except FRV, HPPA, IA64 and MIPS.  Note that -z relro can increase
 232   disk and memory size.
 233
 234 * Support for -z noreloc-overflow in the x86-64 ELF linker to disable
 235   relocation overflow check.
 236
 237 * Add -z common/-z nocommon options for ELF targets to control whether to
 238   convert common symbols to the STT_COMMON type during a relocatable link.
 239
 240 * Support for -z nodynamic-undefined-weak in the x86 ELF linker, which
 241   avoids dynamic relocations against undefined weak symbols in executable.
 242
 243 * The NOCROSSREFSTO command was added to the linker script language.
 244
 245 * Add --no-apply-dynamic-relocs to the AArch64 linker to do not apply link-time
 246   values for dynamic relocations.
 247
 248 Changes in 2.26:
 249
 250 * Add --fix-stm32l4xx-629360 to the ARM linker to enable a link-time
 251   workaround for a bug in the bus matrix / memory controller for some of
 252   the STM32 Cortex-M4 based products (STM32L4xx)
 253
 254 * Add a configure option --enable-compressed-debug-sections={all,ld} to
 255   decide whether DWARF debug sections should be compressed by default.
 256
 257 * Add support for the ARC EM/HS, and ARC600/700 architectures.
 258
 259 * Experimental support for linker garbage collection (--gc-sections)
 260   has been enabled for COFF and PE based targets.
 261
 262 * New command-line option for ELF targets to compress DWARF debug
 263   sections, --compress-debug-sections=[none|zlib|zlib-gnu|zlib-gabi].
 264
 265 * New command-line option, --orphan-handling=[place|warn|error|discard], to
 266   adjust how orphan sections are handled.  The default is 'place' which gives
 267   the current behaviour, 'warn' and 'error' issue a warning or error
 268   respectively when orphan sections are found, and 'discard' will discard all
 269   orphan sections.
 270
 271 * Add support for LLVM plugin.
 272
 273 * Add --print-memory-usage option to report memory blocks usage.
 274
 275 * Add --require-defined option, it's like --undefined except the new symbol
 276   must be defined by the end of the link.
 277
 278 Changes in 2.25:
 279
 280 * PE binaries now once again contain real timestamps by default.  To disable
 281   the inclusion of a timestamp in a PE binary, use the --no-insert-timestamp
 282   command-line option.
 283
 284 * Replace support for openrisc and or32 with support for or1k.
 285
 286 * Add support for the --build-id command-line option to COFF based targets.
 287
 288 * x86/x86_64 pe-coff now supports the --build-id option.
 289
 290 * Add support for the Andes NDS32.
 291
 292 Changes in 2.24:
 293
 294 * Add LOG2CEIL() builtin function to the linker script language
 295
 296 * Add support for the Texas Instruments MSP430X processor.
 297
 298 * Add support for Altera Nios II.
 299
 300 * Add support for the V850E3V5 architecture.
 301
 302 * Add support for the Imagination Technologies Meta processor.
 303
 304 * --enable-new-dtags no longer generates old dtags in addition to new dtags.
 305
 306 * Remove linker support for MIPS ECOFF targets.
 307
 308 * Add ALIGN_WITH_INPUT to the linker script language to force the alignment of
 309   an output section to use the maximum alignment of all its input sections.
 310
 311 Changes in 2.23:
 312
 313 * Enable compressed debug section feature for x86/x86_64 pe-coff.
 314
 315 * Add support for the 64-bit ARM architecture: AArch64.
 316
 317 * Added SORT_NONE to the linker script language to disable section sorting.
 318
 319 * Add a linker-provided symbol when producing ELF output, '__ehdr_start'
 320   to point to the ELF file header (and nearby program headers) in the
 321   program's memory image.
 322
 323 * Add support for S12X processor.
 324
 325 * Add support for the VLE extension to the PowerPC architecture.
 326
 327 * Add support for the Freescale XGATE architecture.
 328
 329 * Add option -f FILE on AIX (for response file).
 330
 331 * Add support for the Renesas RL78 architecture.
 332
 333 * Add support for the Adapteva EPIPHANY architecture.
 334
 335 Changes in 2.22:
 336
 337 * --copy-dt-needed-entries is no longer enabled by default.  Instead
 338   --no-copy-dt-needed-entries is the default.
 339
 340 * INPUT_SECTION_FLAGS has been added to the linker script language
 341   to allow selection of input sections by section header section flags.
 342
 343 * Add support for the Tilera TILEPro and TILE-Gx architectures.
 344
 345 * Added SORT_BY_INIT_PRIORITY to the linker script language to permit
 346   sorting sections by numerical value of the GCC init_priority attribute
 347   encoded in the section name.
 348
 349 Changes in 2.21:
 350
 351 * Linker script expression evaluation is somewhat more sane.  This may
 352   break scripts that depend on quirks of the old expression evaluation.
 353
 354 * Turn off underscoring for x86_64 PE+-COFF targets.  For old behavior the
 355   option --enable-leading-mingw64-underscores can be used on configure of
 356   bfd.
 357
 358 * Add support for the TMS320C6000 (TI C6X) processor family.
 359
 360 * --add-needed renamed to --copy-dt-needed-entries in order to avoid confusion
 361   with --as-needed option.
 362
 363 * Extend .def file syntax by '== <ID>' for imports and exports. This allows
 364   to alias the import/export table name written in PE image.
 365
 366 * Add --exclude-all-symbols option to PE based linkers.  This prevents all
 367   symbols from automatically being exported.
 368
 369 * Add support for the Renesas RX processor.
 370
 371 * Add support for alpha-vms target.
 372
 373 Changes in 2.20:
 374
 375 * GNU/Linux targets now support the STB_GNU_UNIQUE symbol binding.  This is a
 376   GNU extension to the standard set of ELF symbol bindings.  The binding will
 377   be passed on to the dynamic linker which will make sure that in the entire
 378   process there is just one symbol with the given name and type in use.
 379
 380 * PE targets now support a GNU extension to allow the alignment of common
 381   common symbols to be specified.  This support uses custom options in
 382   the .drectve section, which will be disregarded by the native tools.
 383
 384 * PE targets now add primitive support for ELF version scripts; symbols
 385   are not versioned, but the local and global symbol visibility directives
 386   are respected when filtering symbols in auto-export mode.
 387
 388 * New option --no-export-dynamic to undo the effect of the -E and
 389   --export-dynamic options.
 390
 391 * ELF: --warn-alternate-em option to warn if an object has alternate
 392   ELF machine code.
 393
 394 * New script function REGION_ALIAS to add alias names to memory regions.
 395
 396 * PE targets no longer make use of the long section names PE extension to
 397   the COFF format when generating executable images, by default.  The old
 398   (slightly non-conformant) behaviour can still be invoked by using the
 399   new '--enable-long-section-names' command-line option.  It is also enabled
 400   automatically in the presence of un-stripped debug information, as GDB
 401   needs to be able to find the debug info sections by their full names.
 402
 403 * For GNU/Linux systems the linker will now avoid processing any relocations
 404   made against symbols of the STT_GNU_IFUNC type and instead emit them into
 405   the resulting binary for processing by the loader.
 406
 407 * --as-needed now links in a dynamic library if it satisfies undefined
 408   symbols in regular objects, or in other dynamic libraries.  In the
 409   latter case the library is not linked if it is found in a DT_NEEDED
 410   entry of one of the libraries already linked.
 411
 412 * Add a new command-line option, -Ttext-segment ADDR, for ELF targets
 413   to set the address of the first byte of the text segment.
 414
 415 * Add support for Sunplus score architecture.
 416
 417 * Add new option --use-nul-prefixed-import-tables to ld for PE targets to
 418   allow fallback to old import table generation with null element prefix.
 419
 420 * Windows PE systems now support a new --exclude-modules-for-implib option,
 421   allowing users to partition object files and archive members between a DLL
 422   and its associated import library as they are generated during linking.
 423
 424 * Add support for Lattice Mico32 (lm32) architecture.
 425
 426 * Add CR16 ELF --embedded-relocs (used to embedded relocations into binaries
 427   for Embedded-PIC code) option.
 428
 429 * Add to the PE/PE+ targets the support of two different kinds of
 430   pseudo-relocations.  They can be selected by the switches
 431   --enable-runtime-pseudo-reloc-v1 and --enable-runtime-pseudo-reloc-v2.
 432   For the switch --enable-runtime-pseudo-reloc it uses for 32-bit
 433   runtime pseudo relocation version one, for 64-bit the version two.
 434
 435 Changes in 2.19:
 436
 437 * Linker scripts support a new INSERT command that makes it easier to
 438   augment the default script.
 439
 440 * Linker script input section filespecs may now specify a file within an
 441   archive by writing "archive:file".
 442
 443 * The --sort-common switch now has an optional argument which specifies the
 444   direction of sorting.
 445
 446 * The M68K linker now supports multiple GOT generation schemes controlled via
 447   the --got=<type> command-line option.
 448
 449 * The ARM EABI linker will now generate stubs for function calls to symbols
 450   that are too far away.  The placement of the stubs is controlled by a new
 451   linker command-line option: --stub-group-size=N.
 452
 453 Changes in 2.18:
 454
 455 * Linker sources now released under version 3 of the GNU General Public
 456   License.
 457
 458 * ELF: New --build-id option to generate a unique per-binary identifier
 459   embedded in a note section.
 460
 461 * Added support for National Semicondutor CompactRISC (ie CR16) target.
 462
 463 * -l:foo now searches the library path for a filename called foo,
 464   without converting it to libfoo.a or libfoo.so.
 465
 466 * Add a new command-line option '--default-script=FILE' or '-dT FILE'
 467   which specifies a replacement for the built in, default linker
 468   script.
 469
 470 * ELF: Add -Bsymbolic-functions, --dynamic-list-cpp-new, which puts C++
 471   operator new and delete on the dynamic list, and --dynamic-list-data,
 472   builtin list for --dynamic-list, which puts global data symbols on the
 473   dynamic list.
 474
 475 * Add support for x86_64 PE+ target.
 476
 477 * Add support for Score target.
 478
 479 * ELF: Add --dynamic-list option to specify a list of global symbols
 480   whose references shouldn't be bound to the definition within the
 481   shared library, or a list of symbols which should be added to the
 482   symbol table in the executable.
 483
 484 * The default output section LMA has changed for allocatable sections from
 485   being equal to VMA, to keeping the difference between LMA and VMA the same as
 486   the previous output section in the same region.  This is a more useful
 487   default when using overlays and other cases where you specify an LMA
 488   differing from the VMA for some sections.
 489
 490 * New switch: --print-gc-sections to list any sections removed by garabge
 491   collection.
 492
 493 * ARM: Added --vfp11-denorm-fix option to work around an erratum in current
 494   VFP11 coprocessors.
 495
 496 Changes in 2.17:
 497
 498 * Support for the Infineon XC16X has been added by KPIT Cummins Infosystems.
 499
 500 * Modify the Linux linker search order to better match ld.so search order.
 501   Look for DT_NEEDED libraries in paths specified by ld.so.conf before
 502   searching the default directories, rather than vice versa.
 503   Use $prefix/etc/ld.so.conf if it exists, otherwise /etc/ld.so.conf.
 504
 505 * PE-COFF: Forward exports from DLL's can now be specified in .def files
 506   passed directly to ld.
 507
 508 * Support for the Z80 processor family has been added.
 509
 510 * Add support for the "@<file>" syntax to the command line, so that extra
 511   switches can be read from <file>.
 512
 513 Changes in 2.16:
 514
 515 * Support for the R_ARM_V4BX relocation as defined in the ARM AAELF
 516   specification has been added via the --fix-v4bx command-line option.
 517
 518 * New linker script construct AS_NEEDED(), which sets the --as-needed flag
 519   for input files listed inside of it.
 520
 521 * A new command-line option, --sysroot, can be used to override the
 522   default sysroot location.  It only applies to toolchains that were
 523   configured using --with-sysroot.
 524
 525 * New linker script functions: ORIGIN() and LENGTH() which return information
 526   about a specified memory region.
 527
 528 * Port to MAXQ processor contributed by HCL Tech.
 529
 530 * Added SEGMENT_START to the linker script language to permit the user to
 531   override the base address for a segment from the command-line.
 532
 533 * ELF: --warn-shared-textrel option to warn if adding a DT_TEXTREL to a shared
 534   object.
 535
 536 * Added SORT_BY_NAME and SORT_BY_ALIGNMENT to the linker script
 537   language to permit sorting sections by section name or section
 538   maximum alignment.
 539
 540 * Added a new linker command-line switch, --sort-section name|alignment,
 541   to sort sections by section name or maximum alignment.
 542
 543 * ELF: --add-needed/--no-add-needed options to control if a DT_NEEDED tag
 544   should be added when a shared library comes from DT_NEEDED tags.
 545
 546 * Support for the crx-elf target added.
 547
 548 * Support for the sh-symbianelf target added.
 549
 550 * A new linker command-line switch has been added which allows the hash table
 551   size to be set to a suitable prime value near to its argument.  This switch
 552   is --hash-size=<NUMBER>.  Also if the switch --reduce-memory-overheads is
 553   used, and --hash-size has not been used, then the default value will be set
 554   to 1021.
 555
 556 * Linker map files are now generated with an O(N) algorithm for finding symbols
 557   that are defined in each section.  This uses about 40% more memory for
 558   symbols than the old O(N^2) algorithm.  You can use the new
 559   --reduce-memory-overheads option to select the old algorithm; this option
 560   might also be used in the future to select similar tradeoffs.
 561
 562 Changes in 2.15:
 563
 564 * ELF: --as-needed/--no-as-needed options to control if a DT_NEEDED tag should
 565   be added only when a shared library is referenced.
 566
 567 * PE: --large-address-aware option to indicate executables support virtual
 568   addresses greater than 2 gigabytes.
 569
 570 * DWARF 2 support for i386pe added.
 571
 572 * The linker script operator DEFINED() will now yield 1 only for a symbol that
 573   is defined before the statement where DEFINED is used.
 574
 575 * The MIPS --embedded-relocs (used to embed relocations into binaries for
 576   Embedded-PIC code) is deprecated and will be removed in a future release.
 577
 578 * cr16c support added by NSC.
 579
 580 * m32r Linux (ELF) support added by Renesas.
 581
 582 * Improved linker's handling of unresolved symbols.  The switch
 583   --unresolved-symbols=<method> has been added to tell the linker when it
 584   should report them and the switch --warn-unresolved-symbols has been added to
 585   make reports be issued as warning messages rather than errors.
 586
 587 Changes in 2.14:
 588
 589 * Added support for Xtensa architecture.
 590
 591 * Added --with-sysroot configure switch to specify a target system root, for
 592   linking against a target filesystem image.
 593
 594 * Added --accept-unknown-linker-format to restore old linker behaviour (pre
 595   2.14) of silently accepting and linking in any files in an unknown binary
 596   file format.
 597
 598 * Added --no-omagic to undo the effects of the -N option.
 599
 600 * Support for Texas Instruments TMS320C4x and TMS320C3x series of
 601   DSP's contributed by Michael Hayes and Svein E. Seldal.
 602
 603 * Added --with-lib-path configure switch to specify default value for
 604   LIB_PATH.
 605
 606 * ARM port to QNX operating system added by Graeme Peterson.
 607
 608 * IP2K support added by Denis Chertykov.
 609
 610 Changes in 2.13:
 611
 612 * Support for the Fujitsu FRV architecture added by Red Hat. Models for FR400
 613   and FR500 included.
 614
 615 Changes in version 2.13:
 616
 617 * DEC VAX ELF support, by Matt Thomas.
 618
 619 Changes in version 2.12:
 620
 621 * Support for Don Knuth's MMIX, by Hans-Peter Nilsson.
 622
 623 * Support for the OpenRISC 32-bit embedded processor by OpenCores.
 624
 625 * Support for -z nocopyreloc in the x86 ELF linker, which disables
 626   production of copy relocs.  Warning: using this option may result in
 627   non-sharable applications.
 628
 629 * Support for -z combreloc in the ELF linker, which puts dynamic
 630   relocations against the same symbol together, so that dynamic linker
 631   can use an one-entry symbol lookup cache.
 632
 633 * Support for ELF SHF_MERGE section merging, by Jakub Jelinek.
 634
 635 Changes in version 2.11:
 636
 637 * Support for AMD x86-64 architecture, by Jan Hubicka, SuSE Labs.
 638
 639 * Support added for eliminating duplicate DWARF2 debug information by
 640   having the compiler generate the information in sections called
 641   .gnu.linkonce.wi.XXXX where XXXX is a checksum for the contents.  The
 642   linker then merges these sections together into the normal .debug_info
 643   section.
 644
 645 * The native ELF linker now searches the directories in DT_RUNPATH or
 646   DT_RPATH of a shared library for shared libraries needed by it.
 647
 648 * TI C54x support, by Timothy Wall.
 649
 650 * Added command-line switch --section-start to set the start address of any
 651   specified section.
 652
 653 * Added ability to emit full relocation information in linked executables,
 654   enabled by --emit-relocs.  Some post-linkage optimization tools need
 655   this information in order to be able to correctly identify and perform
 656   symbol relative addressing in the event of changes in section contents
 657   (instructions being added or deleted, extending data sections, etc.)
 658
 659 * Support for i860, by Jason Eckhardt (preliminary, alpha quality).
 660
 661 * Support for CRIS (Axis Communications ETRAX series).
 662
 663 * Support for PDP-11 and 2.11BSD a.out format, by Lars Brinkhoff.
 664
 665 Changes in version 2.10:
 666
 667 * Added AT> to the linker script language to allow load-time allocation of
 668   sections into regions.
 669
 670 * Added garbage collection of unused sections, enabled by --gc-sections.
 671   It does require a bit of backend support; currently implemented are
 672   arm-elf, avr-elf, d10v-elf, fr30-elf, i386-elf, m32r-elf, m68k-elf,
 673   mcore-elf, mips-elf, mn10300-elf, ppc-elf, sh-elf, sparc-elf, and v850-elf.
 674   Others will ignore the option.
 675
 676 * Added SORT to the linker script language to permit sorting sections by file
 677   name or section name.
 678
 679 * Added EXTERN to the linker script language as an equivalent to the -u
 680   command-line option.
 681
 682 * Added ASSERT to the linker script language.
 683
 684 * Added EXCLUDE_FILE to the linker script language for further control over
 685   wildcard file names.
 686
 687 * Added -O option to optimize linker output (as of this writing, this only
 688   affects ELF shared library generation).
 689
 690 * The -e option now accepts a number as well as a symbol name.
 691
 692 * Added --no-undefined option to disallow undefined symbols when creating a
 693   shared library.
 694
 695 * The linker now issues a warning, not an error, for an undefined symbol when
 696   using -Bsymbolic; use the new --no-undefined option to get the old
 697   behaviour.
 698
 699 * Added --demangle and --no-demangle options.
 700
 701 Changes in version 2.9:
 702
 703 * Added SQUAD to the linker script language.
 704
 705 * New option --no-warn-mismatch.
 706
 707 * The MEMORY command now parses the attributes to determine where sections that
 708   are not placed in a specific memory region are placed.
 709
 710 Changes in version 2.8:
 711
 712 * Linker scripts may now contain shell wildcard characters for file and section
 713   names.
 714
 715 * The linker now supports symbol versions in ELF.
 716
 717 * The NOCROSSREFS command was added to the linker script language.
 718
 719 * The LOADADDR expression was added to the linker script language.
 720
 721 * MAX and MIN functions were added to the linker script language.
 722
 723 * The OVERLAY construct was added to the linker script language.
 724
 725 * New option --warn-section-align to warn when the address of an output section
 726   changes due to alignment of an input section.
 727
 728 * New options --filter/-F and --auxiliary/-f.
 729
 730 Changes in version 2.7:
 731
 732 * New option --cref to print out a cross reference table.
 733
 734 * New option --wrap SYMBOL.
 735
 736 * New option --no-whole-archive, to turn off the effect of --whole-archive.
 737
 738 * Input sections assigned to the output section /DISCARD/ in the linker script
 739   are not included in the output file.
 740
 741 * The SunOS and ELF linkers now merge stabs debugging information which uses
 742   the N_BINCL and N_EINCL stab types.  This reduces the amount of debugging
 743   information generated.
 744
 745 Changes in version 2.6:
 746
 747 * When an ELF section name is representable as a C identifier (this is not true
 748 of most ELF section names), the linker will automatically define symbols
 749 __start_SECNAME and __stop_SECNAME, where SECNAME is the section name, at the
 750 beginning and the end of the section.  This is used by glibc.
 751
 752   Addendum: Current versions of the linker (at least for version 2.18 onwards
 753 and possibly much earlier as well) place two restrictions on this feature:  The
 754 symbols are only implemented for orphaned sections, not for explicitly placed
 755 sections and they are PROVIDEd rather than being defined.
 756
 757 * When an ELF section named .gnu.warning is encountered in an input file, the
 758 contents of the section are displayed as an error message, and the section is
 759 not copied into the output file.  This is used by glibc.
 760
 761 * When an ELF section named .gnu.warning.SYMBOL is encountered in an input
 762 file, and the symbol SYMBOL is referenced by some object file, the contents of
 763 the section are displayed as an error message.  The section is not copied into
 764 the output file, unless doing a relocatable or shared link.  This is used by
 765 glibc.
 766
 767 * New options -split-by-reloc and -split-by-file.
 768
 769 * The linker now supports linking PIC compiled code on SPARC SunOS.  It can
 770 also create SPARC SunOS shared libraries, and, like the native SunOS linker,
 771 will do so whenever there is an undefined symbol in the link and neither the -e
 772 nor the -r option was used.
 773
 774 * The -rpath option may be used on SunOS to set the list of directories to be
 775 searched at run time.  This overrides the default of building the list from the
 776 -L options.
 777
 778 * The COFF linker now combines debugging information for structs, unions, and
 779 enums, so that even if the same type is defined in multiple input files it will
 780 only be defined once in the output file.  The --traditional-format switch will
 781 prevent this optimization.
 782
 783 Changes in version 2.5:
 784
 785 * The linker now supports linking against SunOS shared libraries.  It still can
 786 not link SunOS PIC (Position Independent Code) files, so it can not be used to
 787 generate shared libraries.
 788
 789 * The linker now supports linking against ELF shared libraries for the i386
 790 (UnixWare) and SPARC (Solaris).  It can also link ELF PIC files, and can be
 791 used to generate shared libraries.  Shared library generation is not well
 792 tested; please report any problems encountered.  The linker is now enabled for
 793 Solaris again.
 794
 795 * Eric Youngdale has contributed Linux support code, including linking against
 796 Linux a.out shared libraries.  The linker produces Linux QMAGIC binaries.
 797
 798 * The ELF backend has been converted to the new linker code.  To use the new
 799 ELF linker, each particular target requires a relocation function.  So far,
 800 this function has been written for i386 (UnixWare), SPARC (Solaris) MIPS (Irix
 801 5), and HPPA ELF targets.
 802
 803 * The -( (--start-group) and -) (--end-group) options have been added to
 804 support searching a group of archives as though they were a single archive.
 805 This can also be used in a linker script, as GROUP ( files ).
 806
 807 * When a file is named on the command line, and the linker does not recognize
 808 it as an object file, the linker will now treat the file as a linker script
 809 file.  A linker script named in this way augments, but does not replace, the
 810 default linker script.
 811
 812 * The -warn-once option was added.  It causes the linker to only warn once per
 813 undefined symbol, rather than once per reference.
 814
 815 * The COFF backend has been converted to the new linker code.  As with ELF, to
 816 use the new linker, each particular target requires a relocation function.  So
 817 far, this function has been written for the i386, m68k, a29k and SH targets.
 818
 819 * The -V flag was made a synonym for -v, for SVR4 compatibility.  The old -V
 820 behaviour is available via --verbose.
 821
 822 Changes in version 2.4:
 823
 824 * New linker code, by Steve Chamberlain and Ian Taylor.  For a.out and ecoff
 825   formats (so far), this should result in considerable savings in time
 826   and memory used while linking; slightly poorer performance than
 827   before for formats not converted yet.
 828
 829 * Command-line parsing is no longer done with flex.  This means
 830   oddball characters in filenames won't get treated as argument
 831   separators.
 832
 833 * HP-PA ELF support, by Jeff Law.  (No SOM support yet.)
 834
 835 * Mach i386 support, by David Mackenzie.
 836
 837 * Irix 4 shared libraries are now supported (Irix 5 uses ELF, and ELF shared
 838   libraries are not yet supported).
 839
 840 * COFF shared libraries (as on SCO) should work as well.
 841
 842 * The linker is disabled for Solaris.  (Actually, it was in 2.3 also, I just
 843   forgot to note it.)  Some of their C library routines don't work when
 844   statically linked, and the GNU linker doesn't support dynamic linking yet.
 845
 846 Changes in version 2.3:
 847
 848 * Weak symbols are now supported.
 849
 850 * ELF support has been added.  The linker has been bootstrapped on
 851   UnixWare and Solaris.
 852
 853 * Alpha OSF/1 support has been added (non dynamic linking only).
 854
 855 Changes in version 2.2:
 856
 857 * The `bfd' library has been updated to reduce a.out-format string
 858   table size.  The effect of this is that files linked from many input
 859   files with duplicate symbols (`-g' debugging records, or identical
 860   static symbols) should be much smaller.
 861
 862 Changes in version 2.1:
 863
 864 * The ld -ySYMBOL flag (to trace references to SYMBOL) is now implemented.
 865
 866 * There is now support for writing ECOFF files, so ld and the
 867   other utilities should work on Risc/Ultrix and Irix.
 868
 869 \f
 870 Copyright (C) 2012-2021 Free Software Foundation, Inc.
 871
 872 Copying and distribution of this file, with or without modification,
 873 are permitted in any medium without royalty provided the copyright
 874 notice and this notice are preserved.
 875
 876 Local variables:
 877 fill-column: 79
 878 End: