ld/NEWS

   1 -*- text -*-
   2
   3 Changes in 2.33:
   4
   5 * Add command-line option --no-print-map-discarded.
   6
   7 * The Cortex-A53 Erratum 843419 workaround now supports a choice of which
   8   workaround to use.  The option --fix-cortex-a53-843419 now takes an
   9   optional argument --fix-cortex-a53-843419[=full|adr|adrp] which can be
  10   used to force a particular workaround to be used.  See --help for AArch64
  11   for more details.
  12
  13 Changes in 2.33:
  14
  15 * Add target handlers for AArch64 for ELF GNU program properties.
  16
  17 * Add support for GNU_PROPERTY_AARCH64_FEATURE_1_BTI in ELF GNU program
  18   properties in the AArch64 ELF linker.
  19
  20 * Add support for GNU_PROPERTY_AARCH64_FEATURE_1_PAC in ELF GNU program
  21   properties in the AArch64 ELF linker.
  22
  23 * Add -z force-bti for AArch64 to enable GNU_PROPERTY_AARCH64_FEATURE_1_BTI
  24   on output while warning about missing GNU_PROPERTY_AARCH64_FEATURE_1_BTI
  25   on inputs and use PLTs protected with BTI.
  26
  27 * Add -z pac-plt for AArch64 to pick PAC enabled PLTs.
  28
  29 Changes in 2.32:
  30
  31 * Report property change in linker map file when merging GNU properties.
  32
  33 * Add support for the C-SKY processor series.
  34
  35 * -t now doesn't report members within archives, unless -t is given twice.
  36   A single -t is now more useful when generating a list of files that should be
  37   packaged for a linker bug report.  For example:
  38     gcc hello.c -save-temps -Wl,-t | xargs realpath | sort | uniq > files
  39     tar cJf test.tar.xz `cat files`
  40
  41 Changes in 2.31:
  42
  43 * Speed up direct linking with DLLs for Cygwin and Mingw targets.
  44
  45 * Add a configure option --enable-separate-code to decide whether
  46   -z separate-code should be enabled in ELF linker by default.  Default
  47   to yes for Linux/x86 targets.  Note that -z separate-code can increase
  48   disk and memory size.
  49
  50 Changes in 2.30:
  51
  52 * Add -z separate-code to generate separate code PT_LOAD segment.
  53
  54 * Add "-z undefs" command-line option as the inverse of the "-z defs" option.
  55
  56 * Add -z globalaudit command-line option to force audit libraries to be run
  57   for every dynamic object loaded by an executable - provided that the loader
  58   supports this functionality.
  59
  60 * Tighten linker script grammar around file name specifiers to prevent the use
  61   of SORT_BY_ALIGNMENT and SORT_BY_INIT_PRIORITY on filenames.  These would
  62   previously be accepted but had no effect.
  63
  64 * The EXCLUDE_FILE directive can now be placed within any SORT_* directive
  65   within input section lists.
  66
  67 Changes in 2.29:
  68
  69 * Support for -z shstk in the x86 ELF linker to generate
  70   GNU_PROPERTY_X86_FEATURE_1_SHSTK in ELF GNU program properties.
  71
  72 * Add support for GNU_PROPERTY_X86_FEATURE_1_SHSTK in ELF GNU program
  73   properties in the x86 ELF linker.
  74
  75 * Add support for GNU_PROPERTY_X86_FEATURE_1_IBT in ELF GNU program
  76   properties in the x86 ELF linker.
  77
  78 * Support for -z ibtplt in the x86 ELF linker to generate IBT-enabled
  79   PLT.
  80
  81 * Support for -z ibt in the x86 ELF linker to generate IBT-enabled
  82   PLT as well as GNU_PROPERTY_X86_FEATURE_1_IBT in ELF GNU program
  83   properties.
  84
  85 * Add support for ELF SHF_GNU_MBIND and PT_GNU_MBIND_XXX.
  86
  87 * Add support for ELF GNU program properties.
  88
  89 * Add support for the Texas Instruments PRU processor.
  90
  91 * When configuring for arc*-*-linux* targets the default linker emulation will
  92   change if --with-cpu=nps400 is used at configure time.
  93
  94 * Improve assignment of LMAs to orphan sections in some edge cases where a
  95   mixture of both AT>LMA_REGION and AT(LMA) are used.
  96
  97 * Orphan sections placed after an empty section that has an AT(LMA) will now
  98   take an load memory address starting from LMA.
  99
 100 * Section groups can now be resolved (the group deleted and the group members
 101   placed like normal sections) at partial link time either using the new linker
 102   option --force-group-allocation or by placing FORCE_GROUP_ALLOCATION into the
 103   linker script.
 104
 105 Changes in 2.28:
 106
 107 * The EXCLUDE_FILE linker script construct can now be applied outside of the
 108   section list in order for the exclusions to apply over all input sections in
 109   the list.
 110
 111 * Add support for the RISC-V architecture.
 112
 113 * The command-line option --no-eh-frame-hdr can now be used in ELF based
 114   linkers to disable the automatic generation of .eh_frame_hdr sections.
 115
 116 * Add --in-implib=<infile> to the ARM linker to enable specifying a set of
 117   Secure Gateway veneers that must exist in the output import library specified
 118   by --out-implib=<outfile> and the address they must have.  As such,
 119   --in-implib is only supported in combination with --cmse-implib.
 120
 121 * Extended the --out-implib=<file> option, previously restricted to x86 PE
 122   targets, to any ELF based target.  This allows the generation of an import
 123   library for an ELF executable, which can then be used by another application
 124   to link against the executable.
 125
 126 Changes in 2.27:
 127
 128 * Add a configure option --enable-relro to decide whether -z relro should
 129   be enabled in ELF linker by default.  Default to yes for all Linux
 130   targets except FRV, HPPA, IA64 and MIPS.  Note that -z relro can increase
 131   disk and memory size.
 132
 133 * Support for -z noreloc-overflow in the x86-64 ELF linker to disable
 134   relocation overflow check.
 135
 136 * Add -z common/-z nocommon options for ELF targets to control whether to
 137   convert common symbols to the STT_COMMON type during a relocatable link.
 138
 139 * Support for -z nodynamic-undefined-weak in the x86 ELF linker, which
 140   avoids dynamic relocations against undefined weak symbols in executable.
 141
 142 * The NOCROSSREFSTO command was added to the linker script language.
 143
 144 * Add --no-apply-dynamic-relocs to the AArch64 linker to do not apply link-time
 145   values for dynamic relocations.
 146
 147 Changes in 2.26:
 148
 149 * Add --fix-stm32l4xx-629360 to the ARM linker to enable a link-time
 150   workaround for a bug in the bus matrix / memory controller for some of
 151   the STM32 Cortex-M4 based products (STM32L4xx)
 152
 153 * Add a configure option --enable-compressed-debug-sections={all,ld} to
 154   decide whether DWARF debug sections should be compressed by default.
 155
 156 * Add support for the ARC EM/HS, and ARC600/700 architectures.
 157
 158 * Experimental support for linker garbage collection (--gc-sections)
 159   has been enabled for COFF and PE based targets.
 160
 161 * New command-line option for ELF targets to compress DWARF debug
 162   sections, --compress-debug-sections=[none|zlib|zlib-gnu|zlib-gabi].
 163
 164 * New command-line option, --orphan-handling=[place|warn|error|discard], to
 165   adjust how orphan sections are handled.  The default is 'place' which gives
 166   the current behaviour, 'warn' and 'error' issue a warning or error
 167   respectively when orphan sections are found, and 'discard' will discard all
 168   orphan sections.
 169
 170 * Add support for LLVM plugin.
 171
 172 * Add --print-memory-usage option to report memory blocks usage.
 173
 174 * Add --require-defined option, it's like --undefined except the new symbol
 175   must be defined by the end of the link.
 176
 177 Changes in 2.25:
 178
 179 * PE binaries now once again contain real timestamps by default.  To disable
 180   the inclusion of a timestamp in a PE binary, use the --no-insert-timestamp
 181   command-line option.
 182
 183 * Replace support for openrisc and or32 with support for or1k.
 184
 185 * Add support for the --build-id command-line option to COFF based targets.
 186
 187 * x86/x86_64 pe-coff now supports the --build-id option.
 188
 189 * Add support for the Andes NDS32.
 190
 191 Changes in 2.24:
 192
 193 * Add LOG2CEIL() builtin function to the linker script language
 194
 195 * Add support for the Texas Instruments MSP430X processor.
 196
 197 * Add support for Altera Nios II.
 198
 199 * Add support for the V850E3V5 architecture.
 200
 201 * Add support for the Imagination Technologies Meta processor.
 202
 203 * --enable-new-dtags no longer generates old dtags in addition to new dtags.
 204
 205 * Remove linker support for MIPS ECOFF targets.
 206
 207 * Add ALIGN_WITH_INPUT to the linker script language to force the alignment of
 208   an output section to use the maximum alignment of all its input sections.
 209
 210 Changes in 2.23:
 211
 212 * Enable compressed debug section feature for x86/x86_64 pe-coff.
 213
 214 * Add support for the 64-bit ARM architecture: AArch64.
 215
 216 * Added SORT_NONE to the linker script language to disable section sorting.
 217
 218 * Add a linker-provided symbol when producing ELF output, '__ehdr_start'
 219   to point to the ELF file header (and nearby program headers) in the
 220   program's memory image.
 221
 222 * Add support for S12X processor.
 223
 224 * Add support for the VLE extension to the PowerPC architecture.
 225
 226 * Add support for the Freescale XGATE architecture.
 227
 228 * Add option -f FILE on AIX (for response file).
 229
 230 * Add support for the Renesas RL78 architecture.
 231
 232 * Add support for the Adapteva EPIPHANY architecture.
 233
 234 Changes in 2.22:
 235
 236 * --copy-dt-needed-entries is no longer enabled by default.  Instead
 237   --no-copy-dt-needed-entries is the default.
 238
 239 * INPUT_SECTION_FLAGS has been added to the linker script language
 240   to allow selection of input sections by section header section flags.
 241
 242 * Add support for the Tilera TILEPro and TILE-Gx architectures.
 243
 244 * Added SORT_BY_INIT_PRIORITY to the linker script language to permit
 245   sorting sections by numerical value of the GCC init_priority attribute
 246   encoded in the section name.
 247
 248 Changes in 2.21:
 249
 250 * Linker script expression evaluation is somewhat more sane.  This may
 251   break scripts that depend on quirks of the old expression evaluation.
 252
 253 * Turn off underscoring for x86_64 PE+-COFF targets.  For old behavior the
 254   option --enable-leading-mingw64-underscores can be used on configure of
 255   bfd.
 256
 257 * Add support for the TMS320C6000 (TI C6X) processor family.
 258
 259 * --add-needed renamed to --copy-dt-needed-entries in order to avoid confusion
 260   with --as-needed option.
 261
 262 * Extend .def file syntax by '== <ID>' for imports and exports. This allows
 263   to alias the import/export table name written in PE image.
 264
 265 * Add --exclude-all-symbols option to PE based linkers.  This prevents all
 266   symbols from automatically being exported.
 267
 268 * Add support for the Renesas RX processor.
 269
 270 * Add support for alpha-vms target.
 271
 272 Changes in 2.20:
 273
 274 * GNU/Linux targets now support the STB_GNU_UNIQUE symbol binding.  This is a
 275   GNU extension to the standard set of ELF symbol bindings.  The binding will
 276   be passed on to the dynamic linker which will make sure that in the entire
 277   process there is just one symbol with the given name and type in use.
 278
 279 * PE targets now support a GNU extension to allow the alignment of common
 280   common symbols to be specified.  This support uses custom options in
 281   the .drectve section, which will be disregarded by the native tools.
 282
 283 * PE targets now add primitive support for ELF version scripts; symbols
 284   are not versioned, but the local and global symbol visibility directives
 285   are respected when filtering symbols in auto-export mode.
 286
 287 * New option --no-export-dynamic to undo the effect of the -E and
 288   --export-dynamic options.
 289
 290 * ELF: --warn-alternate-em option to warn if an object has alternate
 291   ELF machine code.
 292
 293 * New script function REGION_ALIAS to add alias names to memory regions.
 294
 295 * PE targets no longer make use of the long section names PE extension to
 296   the COFF format when generating executable images, by default.  The old
 297   (slightly non-conformant) behaviour can still be invoked by using the
 298   new '--enable-long-section-names' command-line option.  It is also enabled
 299   automatically in the presence of un-stripped debug information, as GDB
 300   needs to be able to find the debug info sections by their full names.
 301
 302 * For GNU/Linux systems the linker will now avoid processing any relocations
 303   made against symbols of the STT_GNU_IFUNC type and instead emit them into
 304   the resulting binary for processing by the loader.
 305
 306 * --as-needed now links in a dynamic library if it satisfies undefined
 307   symbols in regular objects, or in other dynamic libraries.  In the
 308   latter case the library is not linked if it is found in a DT_NEEDED
 309   entry of one of the libraries already linked.
 310
 311 * Add a new command-line option, -Ttext-segment ADDR, for ELF targets
 312   to set the address of the first byte of the text segment.
 313
 314 * Add support for Sunplus score architecture.
 315
 316 * Add new option --use-nul-prefixed-import-tables to ld for PE targets to
 317   allow fallback to old import table generation with null element prefix.
 318
 319 * Windows PE systems now support a new --exclude-modules-for-implib option,
 320   allowing users to partition object files and archive members between a DLL
 321   and its associated import library as they are generated during linking.
 322
 323 * Add support for Lattice Mico32 (lm32) architecture.
 324
 325 * Add CR16 ELF --embedded-relocs (used to embedded relocations into binaries
 326   for Embedded-PIC code) option.
 327
 328 * Add to the PE/PE+ targets the support of two different kinds of
 329   pseudo-relocations.  They can be selected by the switches
 330   --enable-runtime-pseudo-reloc-v1 and --enable-runtime-pseudo-reloc-v2.
 331   For the switch --enable-runtime-pseudo-reloc it uses for 32-bit
 332   runtime pseudo relocation version one, for 64-bit the version two.
 333
 334 Changes in 2.19:
 335
 336 * Linker scripts support a new INSERT command that makes it easier to
 337   augment the default script.
 338
 339 * Linker script input section filespecs may now specify a file within an
 340   archive by writing "archive:file".
 341
 342 * The --sort-common switch now has an optional argument which specifies the
 343   direction of sorting.
 344
 345 * The M68K linker now supports multiple GOT generation schemes controlled via
 346   the --got=<type> command-line option.
 347
 348 * The ARM EABI linker will now generate stubs for function calls to symbols
 349   that are too far away.  The placement of the stubs is controlled by a new
 350   linker command-line option: --stub-group-size=N.
 351
 352 Changes in 2.18:
 353
 354 * Linker sources now released under version 3 of the GNU General Public
 355   License.
 356
 357 * ELF: New --build-id option to generate a unique per-binary identifier
 358   embedded in a note section.
 359
 360 * Added support for National Semicondutor CompactRISC (ie CR16) target.
 361
 362 * -l:foo now searches the library path for a filename called foo,
 363   without converting it to libfoo.a or libfoo.so.
 364
 365 * Add a new command-line option '--default-script=FILE' or '-dT FILE'
 366   which specifies a replacement for the built in, default linker
 367   script.
 368
 369 * ELF: Add -Bsymbolic-functions, --dynamic-list-cpp-new, which puts C++
 370   operator new and delete on the dynamic list, and --dynamic-list-data,
 371   builtin list for --dynamic-list, which puts global data symbols on the
 372   dynamic list.
 373
 374 * Add support for x86_64 PE+ target.
 375
 376 * Add support for Score target.
 377
 378 * ELF: Add --dynamic-list option to specify a list of global symbols
 379   whose references shouldn't be bound to the definition within the
 380   shared library, or a list of symbols which should be added to the
 381   symbol table in the executable.
 382
 383 * The default output section LMA has changed for allocatable sections from
 384   being equal to VMA, to keeping the difference between LMA and VMA the same as
 385   the previous output section in the same region.  This is a more useful
 386   default when using overlays and other cases where you specify an LMA
 387   differing from the VMA for some sections.
 388
 389 * New switch: --print-gc-sections to list any sections removed by garabge
 390   collection.
 391
 392 * ARM: Added --vfp11-denorm-fix option to work around an erratum in current
 393   VFP11 coprocessors.
 394
 395 Changes in 2.17:
 396
 397 * Support for the Infineon XC16X has been added by KPIT Cummins Infosystems.
 398
 399 * Modify the Linux linker search order to better match ld.so search order.
 400   Look for DT_NEEDED libraries in paths specified by ld.so.conf before
 401   searching the default directories, rather than vice versa.
 402   Use $prefix/etc/ld.so.conf if it exists, otherwise /etc/ld.so.conf.
 403
 404 * PE-COFF: Forward exports from DLL's can now be specified in .def files
 405   passed directly to ld.
 406
 407 * Support for the Z80 processor family has been added.
 408
 409 * Add support for the "@<file>" syntax to the command line, so that extra
 410   switches can be read from <file>.
 411
 412 Changes in 2.16:
 413
 414 * Support for the R_ARM_V4BX relocation as defined in the ARM AAELF
 415   specification has been added via the --fix-v4bx command-line option.
 416
 417 * New linker script construct AS_NEEDED(), which sets the --as-needed flag
 418   for input files listed inside of it.
 419
 420 * A new command-line option, --sysroot, can be used to override the
 421   default sysroot location.  It only applies to toolchains that were
 422   configured using --with-sysroot.
 423
 424 * New linker script functions: ORIGIN() and LENGTH() which return information
 425   about a specified memory region.
 426
 427 * Port to MAXQ processor contributed by HCL Tech.
 428
 429 * Added SEGMENT_START to the linker script language to permit the user to
 430   override the base address for a segment from the command-line.
 431
 432 * ELF: --warn-shared-textrel option to warn if adding a DT_TEXTREL to a shared
 433   object.
 434
 435 * Added SORT_BY_NAME and SORT_BY_ALIGNMENT to the linker script
 436   language to permit sorting sections by section name or section
 437   maximum alignment.
 438
 439 * Added a new linker command-line switch, --sort-section name|alignment,
 440   to sort sections by section name or maximum alignment.
 441
 442 * ELF: --add-needed/--no-add-needed options to control if a DT_NEEDED tag
 443   should be added when a shared library comes from DT_NEEDED tags.
 444
 445 * Support for the crx-elf target added.
 446
 447 * Support for the sh-symbianelf target added.
 448
 449 * A new linker command-line switch has been added which allows the hash table
 450   size to be set to a suitable prime value near to its argument.  This switch
 451   is --hash-size=<NUMBER>.  Also if the switch --reduce-memory-overheads is
 452   used, and --hash-size has not been used, then the default value will be set
 453   to 1021.
 454
 455 * Linker map files are now generated with an O(N) algorithm for finding symbols
 456   that are defined in each section.  This uses about 40% more memory for
 457   symbols than the old O(N^2) algorithm.  You can use the new
 458   --reduce-memory-overheads option to select the old algorithm; this option
 459   might also be used in the future to select similar tradeoffs.
 460
 461 Changes in 2.15:
 462
 463 * ELF: --as-needed/--no-as-needed options to control if a DT_NEEDED tag should
 464   be added only when a shared library is referenced.
 465
 466 * PE: --large-address-aware option to indicate executables support virtual
 467   addresses greater than 2 gigabytes.
 468
 469 * DWARF 2 support for i386pe added.
 470
 471 * The linker script operator DEFINED() will now yield 1 only for a symbol that
 472   is defined before the statement where DEFINED is used.
 473
 474 * The MIPS --embedded-relocs (used to embed relocations into binaries for
 475   Embedded-PIC code) is deprecated and will be removed in a future release.
 476
 477 * cr16c support added by NSC.
 478
 479 * m32r Linux (ELF) support added by Renesas.
 480
 481 * Improved linker's handling of unresolved symbols.  The switch
 482   --unresolved-symbols=<method> has been added to tell the linker when it
 483   should report them and the switch --warn-unresolved-symbols has been added to
 484   make reports be issued as warning messages rather than errors.
 485
 486 Changes in 2.14:
 487
 488 * Added support for Xtensa architecture.
 489
 490 * Added --with-sysroot configure switch to specify a target system root, for
 491   linking against a target filesystem image.
 492
 493 * Added --accept-unknown-linker-format to restore old linker behaviour (pre
 494   2.14) of silently accepting and linking in any files in an unknown binary
 495   file format.
 496
 497 * Added --no-omagic to undo the effects of the -N option.
 498
 499 * Support for Texas Instruments TMS320C4x and TMS320C3x series of
 500   DSP's contributed by Michael Hayes and Svein E. Seldal.
 501
 502 * Added --with-lib-path configure switch to specify default value for
 503   LIB_PATH.
 504
 505 * ARM port to QNX operating system added by Graeme Peterson.
 506
 507 * IP2K support added by Denis Chertykov.
 508
 509 Changes in 2.13:
 510
 511 * Support for the Fujitsu FRV architecture added by Red Hat. Models for FR400
 512   and FR500 included.
 513
 514 Changes in version 2.13:
 515
 516 * DEC VAX ELF support, by Matt Thomas.
 517
 518 Changes in version 2.12:
 519
 520 * Support for Don Knuth's MMIX, by Hans-Peter Nilsson.
 521
 522 * Support for the OpenRISC 32-bit embedded processor by OpenCores.
 523
 524 * Support for -z nocopyreloc in the x86 ELF linker, which disables
 525   production of copy relocs.  Warning: using this option may result in
 526   non-sharable applications.
 527
 528 * Support for -z combreloc in the ELF linker, which puts dynamic
 529   relocations against the same symbol together, so that dynamic linker
 530   can use an one-entry symbol lookup cache.
 531
 532 * Support for ELF SHF_MERGE section merging, by Jakub Jelinek.
 533
 534 Changes in version 2.11:
 535
 536 * Support for AMD x86-64 architecture, by Jan Hubicka, SuSE Labs.
 537
 538 * Support added for eliminating duplicate DWARF2 debug information by
 539   having the compiler generate the information in sections called
 540   .gnu.linkonce.wi.XXXX where XXXX is a checksum for the contents.  The
 541   linker then merges these sections together into the normal .debug_info
 542   section.
 543
 544 * The native ELF linker now searches the directories in DT_RUNPATH or
 545   DT_RPATH of a shared library for shared libraries needed by it.
 546
 547 * TI C54x support, by Timothy Wall.
 548
 549 * Added command-line switch --section-start to set the start address of any
 550   specified section.
 551
 552 * Added ability to emit full relocation information in linked executables,
 553   enabled by --emit-relocs.  Some post-linkage optimization tools need
 554   this information in order to be able to correctly identify and perform
 555   symbol relative addressing in the event of changes in section contents
 556   (instructions being added or deleted, extending data sections, etc.)
 557
 558 * Support for i860, by Jason Eckhardt (preliminary, alpha quality).
 559
 560 * Support for CRIS (Axis Communications ETRAX series).
 561
 562 * Support for PDP-11 and 2.11BSD a.out format, by Lars Brinkhoff.
 563
 564 Changes in version 2.10:
 565
 566 * Added AT> to the linker script language to allow load-time allocation of
 567   sections into regions.
 568
 569 * Added garbage collection of unused sections, enabled by --gc-sections.
 570   It does require a bit of backend support; currently implemented are
 571   arm-elf, avr-elf, d10v-elf, fr30-elf, i386-elf, m32r-elf, m68k-elf,
 572   mcore-elf, mips-elf, mn10300-elf, ppc-elf, sh-elf, sparc-elf, and v850-elf.
 573   Others will ignore the option.
 574
 575 * Added SORT to the linker script language to permit sorting sections by file
 576   name or section name.
 577
 578 * Added EXTERN to the linker script language as an equivalent to the -u
 579   command-line option.
 580
 581 * Added ASSERT to the linker script language.
 582
 583 * Added EXCLUDE_FILE to the linker script language for further control over
 584   wildcard file names.
 585
 586 * Added -O option to optimize linker output (as of this writing, this only
 587   affects ELF shared library generation).
 588
 589 * The -e option now accepts a number as well as a symbol name.
 590
 591 * Added --no-undefined option to disallow undefined symbols when creating a
 592   shared library.
 593
 594 * The linker now issues a warning, not an error, for an undefined symbol when
 595   using -Bsymbolic; use the new --no-undefined option to get the old
 596   behaviour.
 597
 598 * Added --demangle and --no-demangle options.
 599
 600 Changes in version 2.9:
 601
 602 * Added SQUAD to the linker script language.
 603
 604 * New option --no-warn-mismatch.
 605
 606 * The MEMORY command now parses the attributes to determine where sections that
 607   are not placed in a specific memory region are placed.
 608
 609 Changes in version 2.8:
 610
 611 * Linker scripts may now contain shell wildcard characters for file and section
 612   names.
 613
 614 * The linker now supports symbol versions in ELF.
 615
 616 * The NOCROSSREFS command was added to the linker script language.
 617
 618 * The LOADADDR expression was added to the linker script language.
 619
 620 * MAX and MIN functions were added to the linker script language.
 621
 622 * The OVERLAY construct was added to the linker script language.
 623
 624 * New option --warn-section-align to warn when the address of an output section
 625   changes due to alignment of an input section.
 626
 627 * New options --filter/-F and --auxiliary/-f.
 628
 629 Changes in version 2.7:
 630
 631 * New option --cref to print out a cross reference table.
 632
 633 * New option --wrap SYMBOL.
 634
 635 * New option --no-whole-archive, to turn off the effect of --whole-archive.
 636
 637 * Input sections assigned to the output section /DISCARD/ in the linker script
 638   are not included in the output file.
 639
 640 * The SunOS and ELF linkers now merge stabs debugging information which uses
 641   the N_BINCL and N_EINCL stab types.  This reduces the amount of debugging
 642   information generated.
 643
 644 Changes in version 2.6:
 645
 646 * When an ELF section name is representable as a C identifier (this is not true
 647 of most ELF section names), the linker will automatically define symbols
 648 __start_SECNAME and __stop_SECNAME, where SECNAME is the section name, at the
 649 beginning and the end of the section.  This is used by glibc.
 650
 651   Addendum: Current versions of the linker (at least for version 2.18 onwards
 652 and possibly much earlier as well) place two restrictions on this feature:  The
 653 symbols are only implemented for orphaned sections, not for explicitly placed
 654 sections and they are PROVIDEd rather than being defined.
 655
 656 * When an ELF section named .gnu.warning is encountered in an input file, the
 657 contents of the section are displayed as an error message, and the section is
 658 not copied into the output file.  This is used by glibc.
 659
 660 * When an ELF section named .gnu.warning.SYMBOL is encountered in an input
 661 file, and the symbol SYMBOL is referenced by some object file, the contents of
 662 the section are displayed as an error message.  The section is not copied into
 663 the output file, unless doing a relocatable or shared link.  This is used by
 664 glibc.
 665
 666 * New options -split-by-reloc and -split-by-file.
 667
 668 * The linker now supports linking PIC compiled code on SPARC SunOS.  It can
 669 also create SPARC SunOS shared libraries, and, like the native SunOS linker,
 670 will do so whenever there is an undefined symbol in the link and neither the -e
 671 nor the -r option was used.
 672
 673 * The -rpath option may be used on SunOS to set the list of directories to be
 674 searched at run time.  This overrides the default of building the list from the
 675 -L options.
 676
 677 * The COFF linker now combines debugging information for structs, unions, and
 678 enums, so that even if the same type is defined in multiple input files it will
 679 only be defined once in the output file.  The --traditional-format switch will
 680 prevent this optimization.
 681
 682 Changes in version 2.5:
 683
 684 * The linker now supports linking against SunOS shared libraries.  It still can
 685 not link SunOS PIC (Position Independent Code) files, so it can not be used to
 686 generate shared libraries.
 687
 688 * The linker now supports linking against ELF shared libraries for the i386
 689 (UnixWare) and SPARC (Solaris).  It can also link ELF PIC files, and can be
 690 used to generate shared libraries.  Shared library generation is not well
 691 tested; please report any problems encountered.  The linker is now enabled for
 692 Solaris again.
 693
 694 * Eric Youngdale has contributed Linux support code, including linking against
 695 Linux a.out shared libraries.  The linker produces Linux QMAGIC binaries.
 696
 697 * The ELF backend has been converted to the new linker code.  To use the new
 698 ELF linker, each particular target requires a relocation function.  So far,
 699 this function has been written for i386 (UnixWare), SPARC (Solaris) MIPS (Irix
 700 5), and HPPA ELF targets.
 701
 702 * The -( (--start-group) and -) (--end-group) options have been added to
 703 support searching a group of archives as though they were a single archive.
 704 This can also be used in a linker script, as GROUP ( files ).
 705
 706 * When a file is named on the command line, and the linker does not recognize
 707 it as an object file, the linker will now treat the file as a linker script
 708 file.  A linker script named in this way augments, but does not replace, the
 709 default linker script.
 710
 711 * The -warn-once option was added.  It causes the linker to only warn once per
 712 undefined symbol, rather than once per reference.
 713
 714 * The COFF backend has been converted to the new linker code.  As with ELF, to
 715 use the new linker, each particular target requires a relocation function.  So
 716 far, this function has been written for the i386, m68k, a29k and SH targets.
 717
 718 * The -V flag was made a synonym for -v, for SVR4 compatibility.  The old -V
 719 behaviour is available via --verbose.
 720
 721 Changes in version 2.4:
 722
 723 * New linker code, by Steve Chamberlain and Ian Taylor.  For a.out and ecoff
 724   formats (so far), this should result in considerable savings in time
 725   and memory used while linking; slightly poorer performance than
 726   before for formats not converted yet.
 727
 728 * Command-line parsing is no longer done with flex.  This means
 729   oddball characters in filenames won't get treated as argument
 730   separators.
 731
 732 * HP-PA ELF support, by Jeff Law.  (No SOM support yet.)
 733
 734 * Mach i386 support, by David Mackenzie.
 735
 736 * Irix 4 shared libraries are now supported (Irix 5 uses ELF, and ELF shared
 737   libraries are not yet supported).
 738
 739 * COFF shared libraries (as on SCO) should work as well.
 740
 741 * The linker is disabled for Solaris.  (Actually, it was in 2.3 also, I just
 742   forgot to note it.)  Some of their C library routines don't work when
 743   statically linked, and the GNU linker doesn't support dynamic linking yet.
 744
 745 Changes in version 2.3:
 746
 747 * Weak symbols are now supported.
 748
 749 * ELF support has been added.  The linker has been bootstrapped on
 750   UnixWare and Solaris.
 751
 752 * Alpha OSF/1 support has been added (non dynamic linking only).
 753
 754 Changes in version 2.2:
 755
 756 * The `bfd' library has been updated to reduce a.out-format string
 757   table size.  The effect of this is that files linked from many input
 758   files with duplicate symbols (`-g' debugging records, or identical
 759   static symbols) should be much smaller.
 760
 761 Changes in version 2.1:
 762
 763 * The ld -ySYMBOL flag (to trace references to SYMBOL) is now implemented.
 764
 765 * There is now support for writing ECOFF files, so ld and the
 766   other utilities should work on Risc/Ultrix and Irix.
 767
 768 \f
 769 Copyright (C) 2012-2019 Free Software Foundation, Inc.
 770
 771 Copying and distribution of this file, with or without modification,
 772 are permitted in any medium without royalty provided the copyright
 773 notice and this notice are preserved.
 774
 775 Local variables:
 776 fill-column: 79
 777 End: