ld/NEWS

   1 -*- text -*-
   2
   3 * Add support for the --build-id command line option to COFF based targets.
   4
   5 * x86/x86_64 pe-coff now supports the --build-id option.
   6
   7 * Add support for the Andes NDS32.
   8
   9 Changes in 2.24:
  10
  11 * Add LOG2CEIL() builtin function to the linker script language
  12
  13 * Add support for the Texas Instruments MSP430X processor.
  14
  15 * Add support for Altera Nios II.
  16
  17 * Add support for the V850E3V5 architecture.
  18
  19 * Add support for the Imagination Technologies Meta processor.
  20
  21 * --enable-new-dtags no longer generates old dtags in addition to new dtags.
  22
  23 * Remove linker support for MIPS ECOFF targets.
  24
  25 * Add ALIGN_WITH_INPUT to the linker script language to force the alignment of
  26   an output section to use the maximum alignment of all its input sections.
  27
  28 Changes in 2.23:
  29
  30 * Enable compressed debug section feature for x86/x86_64 pe-coff.
  31
  32 * Add support for the 64-bit ARM architecture: AArch64.
  33
  34 * Added SORT_NONE to the linker script language to disable section sorting.
  35
  36 * Add a linker-provided symbol when producing ELF output, '__ehdr_start'
  37   to point to the ELF file header (and nearby program headers) in the
  38   program's memory image.
  39
  40 * Add support for S12X processor.
  41
  42 * Add support for the VLE extension to the PowerPC architecture.
  43
  44 * Add support for the Freescale XGATE architecture.
  45
  46 * Add option -f FILE on AIX (for response file).
  47
  48 * Add support for the Renesas RL78 architecture.
  49
  50 * Add support for the Adapteva EPIPHANY architecture.
  51
  52 Changes in 2.22:
  53
  54 * --copy-dt-needed-entries is no longer enabled by default.  Instead
  55   --no-copy-dt-needed-entries is the default.
  56
  57 * INPUT_SECTION_FLAGS has been added to the linker script language
  58   to allow selection of input sections by section header section flags.
  59
  60 * Add support for the Tilera TILEPro and TILE-Gx architectures.
  61
  62 * Added SORT_BY_INIT_PRIORITY to the linker script language to permit
  63   sorting sections by numerical value of the GCC init_priority attribute
  64   encoded in the section name.
  65
  66 Changes in 2.21:
  67
  68 * Linker script expression evaluation is somewhat more sane.  This may
  69   break scripts that depend on quirks of the old expression evaluation.
  70
  71 * Turn off underscoring for x86_64 PE+-COFF targets.  For old behavior the
  72   option --enable-leading-mingw64-underscores can be used on configure of
  73   bfd.
  74
  75 * Add support for the TMS320C6000 (TI C6X) processor family.
  76
  77 * --add-needed renamed to --copy-dt-needed-entries in order to avoid confusion
  78   with --as-needed option.
  79
  80 * Extend .def file syntax by '== <ID>' for imports and exports. This allows
  81   to alias the import/export table name written in PE image.
  82
  83 * Add --exclude-all-symbols option to PE based linkers.  This prevents all
  84   symbols from automatically being exported.
  85
  86 * Add support for the Renesas RX processor.
  87
  88 * Add support for alpha-vms target.
  89
  90 Changes in 2.20:
  91
  92 * GNU/Linux targets now support the STB_GNU_UNIQUE symbol binding.  This is a
  93   GNU extension to the standard set of ELF symbol bindings.  The binding will
  94   be passed on to the dynamic linker which will make sure that in the entire
  95   process there is just one symbol with the given name and type in use.
  96
  97 * PE targets now support a GNU extension to allow the alignment of common
  98   common symbols to be specified.  This support uses custom options in
  99   the .drectve section, which will be disregarded by the native tools.
 100
 101 * PE targets now add primitive support for ELF version scripts; symbols
 102   are not versioned, but the local and global symbol visibility directives
 103   are respected when filtering symbols in auto-export mode.
 104
 105 * New option --no-export-dynamic to undo the effect of the -E and
 106   --export-dynamic options.
 107
 108 * ELF: --warn-alternate-em option to warn if an object has alternate
 109   ELF machine code.
 110
 111 * New script function REGION_ALIAS to add alias names to memory regions.
 112
 113 * PE targets no longer make use of the long section names PE extension to
 114   the COFF format when generating executable images, by default.  The old
 115   (slightly non-conformant) behaviour can still be invoked by using the
 116   new '--enable-long-section-names' command-line option.  It is also enabled
 117   automatically in the presence of un-stripped debug information, as GDB
 118   needs to be able to find the debug info sections by their full names.
 119
 120 * For GNU/Linux systems the linker will now avoid processing any relocations
 121   made against symbols of the STT_GNU_IFUNC type and instead emit them into
 122   the resulting binary for processing by the loader.
 123
 124 * --as-needed now links in a dynamic library if it satisfies undefined
 125   symbols in regular objects, or in other dynamic libraries.  In the
 126   latter case the library is not linked if it is found in a DT_NEEDED
 127   entry of one of the libraries already linked.
 128
 129 * Add a new command line option, -Ttext-segment ADDR, for ELF targets
 130   to set the address of the first byte of the text segment.
 131
 132 * Add support for Sunplus score architecture.
 133
 134 * Add new option --use-nul-prefixed-import-tables to ld for PE targets to
 135   allow fallback to old import table generation with null element prefix.
 136
 137 * Windows PE systems now support a new --exclude-modules-for-implib option,
 138   allowing users to partition object files and archive members between a DLL
 139   and its associated import library as they are generated during linking.
 140
 141 * Add support for Lattice Mico32 (lm32) architecture.
 142
 143 * Add CR16 ELF --embedded-relocs (used to embedded relocations into binaries
 144   for Embedded-PIC code) option.
 145
 146 * Add to the PE/PE+ targets the support of two different kinds of
 147   pseudo-relocations.  They can be selected by the switches
 148   --enable-runtime-pseudo-reloc-v1 and --enable-runtime-pseudo-reloc-v2.
 149   For the switch --enable-runtime-pseudo-reloc it uses for 32-bit
 150   runtime pseudo relocation version one, for 64-bit the version two.
 151
 152 Changes in 2.19:
 153
 154 * Linker scripts support a new INSERT command that makes it easier to
 155   augment the default script.
 156
 157 * Linker script input section filespecs may now specify a file within an
 158   archive by writing "archive:file".
 159
 160 * The --sort-common switch now has an optional argument which specifies the
 161   direction of sorting.
 162
 163 * The M68K linker now supports multiple GOT generation schemes controlled via
 164   the --got=<type> command line option.
 165
 166 * The ARM EABI linker will now generate stubs for function calls to symbols
 167   that are too far away.  The placement of the stubs is controlled by a new
 168   linker command line option: --stub-group-size=N.
 169
 170 Changes in 2.18:
 171
 172 * Linker sources now released under version 3 of the GNU General Public
 173   License.
 174
 175 * ELF: New --build-id option to generate a unique per-binary identifier
 176   embedded in a note section.
 177
 178 * Added support for National Semicondutor CompactRISC (ie CR16) target.
 179
 180 * -l:foo now searches the library path for a filename called foo,
 181   without converting it to libfoo.a or libfoo.so.
 182
 183 * Add a new command line option '--default-script=FILE' or '-dT FILE'
 184   which specifies a replacement for the built in, default linker
 185   script.
 186
 187 * ELF: Add -Bsymbolic-functions, --dynamic-list-cpp-new, which puts C++
 188   operator new and delete on the dynamic list, and --dynamic-list-data,
 189   builtin list for --dynamic-list, which puts global data symbols on the
 190   dynamic list.
 191
 192 * Add support for x86_64 PE+ target.
 193
 194 * Add support for Score target.
 195
 196 * ELF: Add --dynamic-list option to specify a list of global symbols
 197   whose references shouldn't be bound to the definition within the
 198   shared library, or a list of symbols which should be added to the
 199   symbol table in the executable.
 200
 201 * The default output section LMA has changed for allocatable sections from
 202   being equal to VMA, to keeping the difference between LMA and VMA the same as
 203   the previous output section in the same region.  This is a more useful
 204   default when using overlays and other cases where you specify an LMA
 205   differing from the VMA for some sections.
 206
 207 * New switch: --print-gc-sections to list any sections removed by garabge
 208   collection.
 209
 210 * ARM: Added --vfp11-denorm-fix option to work around an erratum in current
 211   VFP11 coprocessors.
 212
 213 Changes in 2.17:
 214
 215 * Support for the Infineon XC16X has been added by KPIT Cummins Infosystems.
 216
 217 * Modify the Linux linker search order to better match ld.so search order.
 218   Look for DT_NEEDED libraries in paths specified by ld.so.conf before
 219   searching the default directories, rather than vice versa.
 220   Use $prefix/etc/ld.so.conf if it exists, otherwise /etc/ld.so.conf.
 221
 222 * PE-COFF: Forward exports from DLL's can now be specified in .def files
 223   passed directly to ld.
 224
 225 * Support for the Z80 processor family has been added.
 226
 227 * Add support for the "@<file>" syntax to the command line, so that extra
 228   switches can be read from <file>.
 229
 230 Changes in 2.16:
 231
 232 * Support for the R_ARM_V4BX relocation as defined in the ARM AAELF
 233   specification has been added via the --fix-v4bx command-line option.
 234
 235 * New linker script construct AS_NEEDED(), which sets the --as-needed flag
 236   for input files listed inside of it.
 237
 238 * A new command-line option, --sysroot, can be used to override the
 239   default sysroot location.  It only applies to toolchains that were
 240   configured using --with-sysroot.
 241
 242 * New linker script functions: ORIGIN() and LENGTH() which return information
 243   about a specified memory region.
 244
 245 * Port to MAXQ processor contributed by HCL Tech.
 246
 247 * Added SEGMENT_START to the linker script language to permit the user to
 248   override the base address for a segment from the command-line.
 249
 250 * ELF: --warn-shared-textrel option to warn if adding a DT_TEXTREL to a shared
 251   object.
 252
 253 * Added SORT_BY_NAME and SORT_BY_ALIGNMENT to the linker script
 254   language to permit sorting sections by section name or section
 255   maximum alignment.
 256
 257 * Added a new linker command line switch, --sort-section name|alignment,
 258   to sort sections by section name or maximum alignment.
 259
 260 * ELF: --add-needed/--no-add-needed options to control if a DT_NEEDED tag
 261   should be added when a shared library comes from DT_NEEDED tags.
 262
 263 * Support for the crx-elf target added.
 264
 265 * Support for the sh-symbianelf target added.
 266
 267 * A new linker command line switch has been added which allows the hash table
 268   size to be set to a suitable prime value near to its argument.  This switch
 269   is --hash-size=<NUMBER>.  Also if the switch --reduce-memory-overheads is
 270   used, and --hash-size has not been used, then the default value will be set
 271   to 1021.
 272
 273 * Linker map files are now generated with an O(N) algorithm for finding symbols
 274   that are defined in each section.  This uses about 40% more memory for
 275   symbols than the old O(N^2) algorithm.  You can use the new
 276   --reduce-memory-overheads option to select the old algorithm; this option
 277   might also be used in the future to select similar tradeoffs.
 278
 279 Changes in 2.15:
 280
 281 * ELF: --as-needed/--no-as-needed options to control if a DT_NEEDED tag should
 282   be added only when a shared library is referenced.
 283
 284 * PE: --large-address-aware option to indicate executables support virtual
 285   addresses greater than 2 gigabytes.
 286
 287 * DWARF 2 support for i386pe added.
 288
 289 * The linker script operator DEFINED() will now yield 1 only for a symbol that
 290   is defined before the statement where DEFINED is used.
 291
 292 * The MIPS --embedded-relocs (used to embed relocations into binaries for
 293   Embedded-PIC code) is deprecated and will be removed in a future release.
 294
 295 * cr16c support added by NSC.
 296
 297 * m32r Linux (ELF) support added by Renesas.
 298
 299 * Improved linker's handling of unresolved symbols.  The switch
 300   --unresolved-symbols=<method> has been added to tell the linker when it
 301   should report them and the switch --warn-unresolved-symbols has been added to
 302   make reports be issued as warning messages rather than errors.
 303
 304 Changes in 2.14:
 305
 306 * Added support for Xtensa architecture.
 307
 308 * Added --with-sysroot configure switch to specify a target system root, for
 309   linking against a target filesystem image.
 310
 311 * Added --accept-unknown-linker-format to restore old linker behaviour (pre
 312   2.14) of silently accepting and linking in any files in an unknown binary
 313   file format.
 314
 315 * Added --no-omagic to undo the effects of the -N option.
 316
 317 * Support for Texas Instruments TMS320C4x and TMS320C3x series of
 318   DSP's contributed by Michael Hayes and Svein E. Seldal.
 319
 320 * Added --with-lib-path configure switch to specify default value for
 321   LIB_PATH.
 322
 323 * ARM port to QNX operating system added by Graeme Peterson.
 324
 325 * IP2K support added by Denis Chertykov.
 326
 327 Changes in 2.13:
 328
 329 * Support for the Fujitsu FRV architecture added by Red Hat. Models for FR400
 330   and FR500 included.
 331
 332 Changes in version 2.13:
 333
 334 * DEC VAX ELF support, by Matt Thomas.
 335
 336 Changes in version 2.12:
 337
 338 * Support for Don Knuth's MMIX, by Hans-Peter Nilsson.
 339
 340 * Support for the OpenRISC 32-bit embedded processor by OpenCores.
 341
 342 * Support for -z nocopyreloc in the x86 ELF linker, which disables
 343   production of copy relocs.  Warning: using this option may result in
 344   non-sharable applications.
 345
 346 * Support for -z combreloc in the ELF linker, which puts dynamic
 347   relocations against the same symbol together, so that dynamic linker
 348   can use an one-entry symbol lookup cache.
 349
 350 * Support for ELF SHF_MERGE section merging, by Jakub Jelinek.
 351
 352 Changes in version 2.11:
 353
 354 * Support for AMD x86-64 architecture, by Jan Hubicka, SuSE Labs.
 355
 356 * Support added for eliminating duplicate DWARF2 debug information by
 357   having the compiler generate the information in sections called
 358   .gnu.linkonce.wi.XXXX where XXXX is a checksum for the contents.  The
 359   linker then merges these sections together into the normal .debug_info
 360   section.
 361
 362 * The native ELF linker now searches the directories in DT_RUNPATH or
 363   DT_RPATH of a shared library for shared libraries needed by it.
 364
 365 * TI C54x support, by Timothy Wall.
 366
 367 * Added command line switch --section-start to set the start address of any
 368   specified section.
 369
 370 * Added ability to emit full relocation information in linked executables,
 371   enabled by --emit-relocs.  Some post-linkage optimization tools need
 372   this information in order to be able to correctly identify and perform
 373   symbol relative addressing in the event of changes in section contents
 374   (instructions being added or deleted, extending data sections, etc.)
 375
 376 * Support for i860, by Jason Eckhardt (preliminary, alpha quality).
 377
 378 * Support for CRIS (Axis Communications ETRAX series).
 379
 380 * Support for PDP-11 and 2.11BSD a.out format, by Lars Brinkhoff.
 381
 382 Changes in version 2.10:
 383
 384 * Added AT> to the linker script language to allow load-time allocation of
 385   sections into regions.
 386
 387 * Added garbage collection of unused sections, enabled by --gc-sections.
 388   It does require a bit of backend support; currently implemented are
 389   arm-elf, avr-elf, d10v-elf, fr30-elf, i386-elf, m32r-elf, m68k-elf,
 390   mcore-elf, mips-elf, mn10300-elf, ppc-elf, sh-elf, sparc-elf, and v850-elf.
 391   Others will ignore the option.
 392
 393 * Added SORT to the linker script language to permit sorting sections by file
 394   name or section name.
 395
 396 * Added EXTERN to the linker script language as an equivalent to the -u
 397   command-line option.
 398
 399 * Added ASSERT to the linker script language.
 400
 401 * Added EXCLUDE_FILE to the linker script language for further control over
 402   wildcard file names.
 403
 404 * Added -O option to optimize linker output (as of this writing, this only
 405   affects ELF shared library generation).
 406
 407 * The -e option now accepts a number as well as a symbol name.
 408
 409 * Added --no-undefined option to disallow undefined symbols when creating a
 410   shared library.
 411
 412 * The linker now issues a warning, not an error, for an undefined symbol when
 413   using -Bsymbolic; use the new --no-undefined option to get the old
 414   behaviour.
 415
 416 * Added --demangle and --no-demangle options.
 417
 418 Changes in version 2.9:
 419
 420 * Added SQUAD to the linker script language.
 421
 422 * New option --no-warn-mismatch.
 423
 424 * The MEMORY command now parses the attributes to determine where sections that
 425   are not placed in a specific memory region are placed.
 426
 427 Changes in version 2.8:
 428
 429 * Linker scripts may now contain shell wildcard characters for file and section
 430   names.
 431
 432 * The linker now supports symbol versions in ELF.
 433
 434 * The NOCROSSREFS command was added to the linker script language.
 435
 436 * The LOADADDR expression was added to the linker script language.
 437
 438 * MAX and MIN functions were added to the linker script language.
 439
 440 * The OVERLAY construct was added to the linker script language.
 441
 442 * New option --warn-section-align to warn when the address of an output section
 443   changes due to alignment of an input section.
 444
 445 * New options --filter/-F and --auxiliary/-f.
 446
 447 Changes in version 2.7:
 448
 449 * New option --cref to print out a cross reference table.
 450
 451 * New option --wrap SYMBOL.
 452
 453 * New option --no-whole-archive, to turn off the effect of --whole-archive.
 454
 455 * Input sections assigned to the output section /DISCARD/ in the linker script
 456   are not included in the output file.
 457
 458 * The SunOS and ELF linkers now merge stabs debugging information which uses
 459   the N_BINCL and N_EINCL stab types.  This reduces the amount of debugging
 460   information generated.
 461
 462 Changes in version 2.6:
 463
 464 * When an ELF section name is representable as a C identifier (this is not true
 465 of most ELF section names), the linker will automatically define symbols
 466 __start_SECNAME and __stop_SECNAME, where SECNAME is the section name, at the
 467 beginning and the end of the section.  This is used by glibc.
 468
 469   Addendum: Current versions of the linker (at least for version 2.18 onwards
 470 and possibly much earlier as well) place two restrictions on this feature:  The
 471 symbols are only implemented for orphaned sections, not for explicitly placed
 472 sections and they are PROVIDEd rather than being defined.
 473
 474 * When an ELF section named .gnu.warning is encountered in an input file, the
 475 contents of the section are displayed as an error message, and the section is
 476 not copied into the output file.  This is used by glibc.
 477
 478 * When an ELF section named .gnu.warning.SYMBOL is encountered in an input
 479 file, and the symbol SYMBOL is referenced by some object file, the contents of
 480 the section are displayed as an error message.  The section is not copied into
 481 the output file, unless doing a relocatable or shared link.  This is used by
 482 glibc.
 483
 484 * New options -split-by-reloc and -split-by-file.
 485
 486 * The linker now supports linking PIC compiled code on SPARC SunOS.  It can
 487 also create SPARC SunOS shared libraries, and, like the native SunOS linker,
 488 will do so whenever there is an undefined symbol in the link and neither the -e
 489 nor the -r option was used.
 490
 491 * The -rpath option may be used on SunOS to set the list of directories to be
 492 searched at run time.  This overrides the default of building the list from the
 493 -L options.
 494
 495 * The COFF linker now combines debugging information for structs, unions, and
 496 enums, so that even if the same type is defined in multiple input files it will
 497 only be defined once in the output file.  The --traditional-format switch will
 498 prevent this optimization.
 499
 500 Changes in version 2.5:
 501
 502 * The linker now supports linking against SunOS shared libraries.  It still can
 503 not link SunOS PIC (Position Independent Code) files, so it can not be used to
 504 generate shared libraries.
 505
 506 * The linker now supports linking against ELF shared libraries for the i386
 507 (UnixWare) and SPARC (Solaris).  It can also link ELF PIC files, and can be
 508 used to generate shared libraries.  Shared library generation is not well
 509 tested; please report any problems encountered.  The linker is now enabled for
 510 Solaris again.
 511
 512 * Eric Youngdale has contributed Linux support code, including linking against
 513 Linux a.out shared libraries.  The linker produces Linux QMAGIC binaries.
 514
 515 * The ELF backend has been converted to the new linker code.  To use the new
 516 ELF linker, each particular target requires a relocation function.  So far,
 517 this function has been written for i386 (UnixWare), SPARC (Solaris) MIPS (Irix
 518 5), and HPPA ELF targets.
 519
 520 * The -( (--start-group) and -) (--end-group) options have been added to
 521 support searching a group of archives as though they were a single archive.
 522 This can also be used in a linker script, as GROUP ( files ).
 523
 524 * When a file is named on the command line, and the linker does not recognize
 525 it as an object file, the linker will now treat the file as a linker script
 526 file.  A linker script named in this way augments, but does not replace, the
 527 default linker script.
 528
 529 * The -warn-once option was added.  It causes the linker to only warn once per
 530 undefined symbol, rather than once per reference.
 531
 532 * The COFF backend has been converted to the new linker code.  As with ELF, to
 533 use the new linker, each particular target requires a relocation function.  So
 534 far, this function has been written for the i386, m68k, a29k and SH targets.
 535
 536 * The -V flag was made a synonym for -v, for SVR4 compatibility.  The old -V
 537 behaviour is available via --verbose.
 538
 539 Changes in version 2.4:
 540
 541 * New linker code, by Steve Chamberlain and Ian Taylor.  For a.out and ecoff
 542   formats (so far), this should result in considerable savings in time
 543   and memory used while linking; slightly poorer performance than
 544   before for formats not converted yet.
 545
 546 * Command-line parsing is no longer done with flex.  This means
 547   oddball characters in filenames won't get treated as argument
 548   separators.
 549
 550 * HP-PA ELF support, by Jeff Law.  (No SOM support yet.)
 551
 552 * Mach i386 support, by David Mackenzie.
 553
 554 * Irix 4 shared libraries are now supported (Irix 5 uses ELF, and ELF shared
 555   libraries are not yet supported).
 556
 557 * COFF shared libraries (as on SCO) should work as well.
 558
 559 * The linker is disabled for Solaris.  (Actually, it was in 2.3 also, I just
 560   forgot to note it.)  Some of their C library routines don't work when
 561   statically linked, and the GNU linker doesn't support dynamic linking yet.
 562
 563 Changes in version 2.3:
 564
 565 * Weak symbols are now supported.
 566
 567 * ELF support has been added.  The linker has been bootstrapped on
 568   UnixWare and Solaris.
 569
 570 * Alpha OSF/1 support has been added (non dynamic linking only).
 571
 572 Changes in version 2.2:
 573
 574 * The `bfd' library has been updated to reduce a.out-format string
 575   table size.  The effect of this is that files linked from many input
 576   files with duplicate symbols (`-g' debugging records, or identical
 577   static symbols) should be much smaller.
 578
 579 Changes in version 2.1:
 580
 581 * The ld -ySYMBOL flag (to trace references to SYMBOL) is now implemented.
 582
 583 * There is now support for writing ECOFF files, so ld and the
 584   other utilities should work on Risc/Ultrix and Irix.
 585
 586 \f
 587 Copyright (C) 2012-2014 Free Software Foundation, Inc.
 588
 589 Copying and distribution of this file, with or without modification,
 590 are permitted in any medium without royalty provided the copyright
 591 notice and this notice are preserved.
 592
 593 Local variables:
 594 fill-column: 79
 595 End: