ld/NEWS

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