ld/NEWS

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