ld/NEWS

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