ld/NEWS

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