ld/NEWS

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