ld/NEWS

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