ld/NEWS

   1 -*- text -*-
   2
   3 * Add support for LLVM plugin.
   4
   5 Changes in 2.25:
   6
   7 * PE binaries now once again contain real timestamps by default.  To disable
   8   the inclusion of a timestamp in a PE binary, use the --no-insert-timestamp
   9   command line option.
  10
  11 * Replace support for openrisc and or32 with support for or1k.
  12
  13 * Add support for the --build-id command line option to COFF based targets.
  14
  15 * x86/x86_64 pe-coff now supports the --build-id option.
  16
  17 * Add support for the Andes NDS32.
  18
  19 Changes in 2.24:
  20
  21 * Add LOG2CEIL() builtin function to the linker script language
  22
  23 * Add support for the Texas Instruments MSP430X processor.
  24
  25 * Add support for Altera Nios II.
  26
  27 * Add support for the V850E3V5 architecture.
  28
  29 * Add support for the Imagination Technologies Meta processor.
  30
  31 * --enable-new-dtags no longer generates old dtags in addition to new dtags.
  32
  33 * Remove linker support for MIPS ECOFF targets.
  34
  35 * Add ALIGN_WITH_INPUT to the linker script language to force the alignment of
  36   an output section to use the maximum alignment of all its input sections.
  37
  38 Changes in 2.23:
  39
  40 * Enable compressed debug section feature for x86/x86_64 pe-coff.
  41
  42 * Add support for the 64-bit ARM architecture: AArch64.
  43
  44 * Added SORT_NONE to the linker script language to disable section sorting.
  45
  46 * Add a linker-provided symbol when producing ELF output, '__ehdr_start'
  47   to point to the ELF file header (and nearby program headers) in the
  48   program's memory image.
  49
  50 * Add support for S12X processor.
  51
  52 * Add support for the VLE extension to the PowerPC architecture.
  53
  54 * Add support for the Freescale XGATE architecture.
  55
  56 * Add option -f FILE on AIX (for response file).
  57
  58 * Add support for the Renesas RL78 architecture.
  59
  60 * Add support for the Adapteva EPIPHANY architecture.
  61
  62 Changes in 2.22:
  63
  64 * --copy-dt-needed-entries is no longer enabled by default.  Instead
  65   --no-copy-dt-needed-entries is the default.
  66
  67 * INPUT_SECTION_FLAGS has been added to the linker script language
  68   to allow selection of input sections by section header section flags.
  69
  70 * Add support for the Tilera TILEPro and TILE-Gx architectures.
  71
  72 * Added SORT_BY_INIT_PRIORITY to the linker script language to permit
  73   sorting sections by numerical value of the GCC init_priority attribute
  74   encoded in the section name.
  75
  76 Changes in 2.21:
  77
  78 * Linker script expression evaluation is somewhat more sane.  This may
  79   break scripts that depend on quirks of the old expression evaluation.
  80
  81 * Turn off underscoring for x86_64 PE+-COFF targets.  For old behavior the
  82   option --enable-leading-mingw64-underscores can be used on configure of
  83   bfd.
  84
  85 * Add support for the TMS320C6000 (TI C6X) processor family.
  86
  87 * --add-needed renamed to --copy-dt-needed-entries in order to avoid confusion
  88   with --as-needed option.
  89
  90 * Extend .def file syntax by '== <ID>' for imports and exports. This allows
  91   to alias the import/export table name written in PE image.
  92
  93 * Add --exclude-all-symbols option to PE based linkers.  This prevents all
  94   symbols from automatically being exported.
  95
  96 * Add support for the Renesas RX processor.
  97
  98 * Add support for alpha-vms target.
  99
 100 Changes in 2.20:
 101
 102 * GNU/Linux targets now support the STB_GNU_UNIQUE symbol binding.  This is a
 103   GNU extension to the standard set of ELF symbol bindings.  The binding will
 104   be passed on to the dynamic linker which will make sure that in the entire
 105   process there is just one symbol with the given name and type in use.
 106
 107 * PE targets now support a GNU extension to allow the alignment of common
 108   common symbols to be specified.  This support uses custom options in
 109   the .drectve section, which will be disregarded by the native tools.
 110
 111 * PE targets now add primitive support for ELF version scripts; symbols
 112   are not versioned, but the local and global symbol visibility directives
 113   are respected when filtering symbols in auto-export mode.
 114
 115 * New option --no-export-dynamic to undo the effect of the -E and
 116   --export-dynamic options.
 117
 118 * ELF: --warn-alternate-em option to warn if an object has alternate
 119   ELF machine code.
 120
 121 * New script function REGION_ALIAS to add alias names to memory regions.
 122
 123 * PE targets no longer make use of the long section names PE extension to
 124   the COFF format when generating executable images, by default.  The old
 125   (slightly non-conformant) behaviour can still be invoked by using the
 126   new '--enable-long-section-names' command-line option.  It is also enabled
 127   automatically in the presence of un-stripped debug information, as GDB
 128   needs to be able to find the debug info sections by their full names.
 129
 130 * For GNU/Linux systems the linker will now avoid processing any relocations
 131   made against symbols of the STT_GNU_IFUNC type and instead emit them into
 132   the resulting binary for processing by the loader.
 133
 134 * --as-needed now links in a dynamic library if it satisfies undefined
 135   symbols in regular objects, or in other dynamic libraries.  In the
 136   latter case the library is not linked if it is found in a DT_NEEDED
 137   entry of one of the libraries already linked.
 138
 139 * Add a new command line option, -Ttext-segment ADDR, for ELF targets
 140   to set the address of the first byte of the text segment.
 141
 142 * Add support for Sunplus score architecture.
 143
 144 * Add new option --use-nul-prefixed-import-tables to ld for PE targets to
 145   allow fallback to old import table generation with null element prefix.
 146
 147 * Windows PE systems now support a new --exclude-modules-for-implib option,
 148   allowing users to partition object files and archive members between a DLL
 149   and its associated import library as they are generated during linking.
 150
 151 * Add support for Lattice Mico32 (lm32) architecture.
 152
 153 * Add CR16 ELF --embedded-relocs (used to embedded relocations into binaries
 154   for Embedded-PIC code) option.
 155
 156 * Add to the PE/PE+ targets the support of two different kinds of
 157   pseudo-relocations.  They can be selected by the switches
 158   --enable-runtime-pseudo-reloc-v1 and --enable-runtime-pseudo-reloc-v2.
 159   For the switch --enable-runtime-pseudo-reloc it uses for 32-bit
 160   runtime pseudo relocation version one, for 64-bit the version two.
 161
 162 Changes in 2.19:
 163
 164 * Linker scripts support a new INSERT command that makes it easier to
 165   augment the default script.
 166
 167 * Linker script input section filespecs may now specify a file within an
 168   archive by writing "archive:file".
 169
 170 * The --sort-common switch now has an optional argument which specifies the
 171   direction of sorting.
 172
 173 * The M68K linker now supports multiple GOT generation schemes controlled via
 174   the --got=<type> command line option.
 175
 176 * The ARM EABI linker will now generate stubs for function calls to symbols
 177   that are too far away.  The placement of the stubs is controlled by a new
 178   linker command line option: --stub-group-size=N.
 179
 180 Changes in 2.18:
 181
 182 * Linker sources now released under version 3 of the GNU General Public
 183   License.
 184
 185 * ELF: New --build-id option to generate a unique per-binary identifier
 186   embedded in a note section.
 187
 188 * Added support for National Semicondutor CompactRISC (ie CR16) target.
 189
 190 * -l:foo now searches the library path for a filename called foo,
 191   without converting it to libfoo.a or libfoo.so.
 192
 193 * Add a new command line option '--default-script=FILE' or '-dT FILE'
 194   which specifies a replacement for the built in, default linker
 195   script.
 196
 197 * ELF: Add -Bsymbolic-functions, --dynamic-list-cpp-new, which puts C++
 198   operator new and delete on the dynamic list, and --dynamic-list-data,
 199   builtin list for --dynamic-list, which puts global data symbols on the
 200   dynamic list.
 201
 202 * Add support for x86_64 PE+ target.
 203
 204 * Add support for Score target.
 205
 206 * ELF: Add --dynamic-list option to specify a list of global symbols
 207   whose references shouldn't be bound to the definition within the
 208   shared library, or a list of symbols which should be added to the
 209   symbol table in the executable.
 210
 211 * The default output section LMA has changed for allocatable sections from
 212   being equal to VMA, to keeping the difference between LMA and VMA the same as
 213   the previous output section in the same region.  This is a more useful
 214   default when using overlays and other cases where you specify an LMA
 215   differing from the VMA for some sections.
 216
 217 * New switch: --print-gc-sections to list any sections removed by garabge
 218   collection.
 219
 220 * ARM: Added --vfp11-denorm-fix option to work around an erratum in current
 221   VFP11 coprocessors.
 222
 223 Changes in 2.17:
 224
 225 * Support for the Infineon XC16X has been added by KPIT Cummins Infosystems.
 226
 227 * Modify the Linux linker search order to better match ld.so search order.
 228   Look for DT_NEEDED libraries in paths specified by ld.so.conf before
 229   searching the default directories, rather than vice versa.
 230   Use $prefix/etc/ld.so.conf if it exists, otherwise /etc/ld.so.conf.
 231
 232 * PE-COFF: Forward exports from DLL's can now be specified in .def files
 233   passed directly to ld.
 234
 235 * Support for the Z80 processor family has been added.
 236
 237 * Add support for the "@<file>" syntax to the command line, so that extra
 238   switches can be read from <file>.
 239
 240 Changes in 2.16:
 241
 242 * Support for the R_ARM_V4BX relocation as defined in the ARM AAELF
 243   specification has been added via the --fix-v4bx command-line option.
 244
 245 * New linker script construct AS_NEEDED(), which sets the --as-needed flag
 246   for input files listed inside of it.
 247
 248 * A new command-line option, --sysroot, can be used to override the
 249   default sysroot location.  It only applies to toolchains that were
 250   configured using --with-sysroot.
 251
 252 * New linker script functions: ORIGIN() and LENGTH() which return information
 253   about a specified memory region.
 254
 255 * Port to MAXQ processor contributed by HCL Tech.
 256
 257 * Added SEGMENT_START to the linker script language to permit the user to
 258   override the base address for a segment from the command-line.
 259
 260 * ELF: --warn-shared-textrel option to warn if adding a DT_TEXTREL to a shared
 261   object.
 262
 263 * Added SORT_BY_NAME and SORT_BY_ALIGNMENT to the linker script
 264   language to permit sorting sections by section name or section
 265   maximum alignment.
 266
 267 * Added a new linker command line switch, --sort-section name|alignment,
 268   to sort sections by section name or maximum alignment.
 269
 270 * ELF: --add-needed/--no-add-needed options to control if a DT_NEEDED tag
 271   should be added when a shared library comes from DT_NEEDED tags.
 272
 273 * Support for the crx-elf target added.
 274
 275 * Support for the sh-symbianelf target added.
 276
 277 * A new linker command line switch has been added which allows the hash table
 278   size to be set to a suitable prime value near to its argument.  This switch
 279   is --hash-size=<NUMBER>.  Also if the switch --reduce-memory-overheads is
 280   used, and --hash-size has not been used, then the default value will be set
 281   to 1021.
 282
 283 * Linker map files are now generated with an O(N) algorithm for finding symbols
 284   that are defined in each section.  This uses about 40% more memory for
 285   symbols than the old O(N^2) algorithm.  You can use the new
 286   --reduce-memory-overheads option to select the old algorithm; this option
 287   might also be used in the future to select similar tradeoffs.
 288
 289 Changes in 2.15:
 290
 291 * ELF: --as-needed/--no-as-needed options to control if a DT_NEEDED tag should
 292   be added only when a shared library is referenced.
 293
 294 * PE: --large-address-aware option to indicate executables support virtual
 295   addresses greater than 2 gigabytes.
 296
 297 * DWARF 2 support for i386pe added.
 298
 299 * The linker script operator DEFINED() will now yield 1 only for a symbol that
 300   is defined before the statement where DEFINED is used.
 301
 302 * The MIPS --embedded-relocs (used to embed relocations into binaries for
 303   Embedded-PIC code) is deprecated and will be removed in a future release.
 304
 305 * cr16c support added by NSC.
 306
 307 * m32r Linux (ELF) support added by Renesas.
 308
 309 * Improved linker's handling of unresolved symbols.  The switch
 310   --unresolved-symbols=<method> has been added to tell the linker when it
 311   should report them and the switch --warn-unresolved-symbols has been added to
 312   make reports be issued as warning messages rather than errors.
 313
 314 Changes in 2.14:
 315
 316 * Added support for Xtensa architecture.
 317
 318 * Added --with-sysroot configure switch to specify a target system root, for
 319   linking against a target filesystem image.
 320
 321 * Added --accept-unknown-linker-format to restore old linker behaviour (pre
 322   2.14) of silently accepting and linking in any files in an unknown binary
 323   file format.
 324
 325 * Added --no-omagic to undo the effects of the -N option.
 326
 327 * Support for Texas Instruments TMS320C4x and TMS320C3x series of
 328   DSP's contributed by Michael Hayes and Svein E. Seldal.
 329
 330 * Added --with-lib-path configure switch to specify default value for
 331   LIB_PATH.
 332
 333 * ARM port to QNX operating system added by Graeme Peterson.
 334
 335 * IP2K support added by Denis Chertykov.
 336
 337 Changes in 2.13:
 338
 339 * Support for the Fujitsu FRV architecture added by Red Hat. Models for FR400
 340   and FR500 included.
 341
 342 Changes in version 2.13:
 343
 344 * DEC VAX ELF support, by Matt Thomas.
 345
 346 Changes in version 2.12:
 347
 348 * Support for Don Knuth's MMIX, by Hans-Peter Nilsson.
 349
 350 * Support for the OpenRISC 32-bit embedded processor by OpenCores.
 351
 352 * Support for -z nocopyreloc in the x86 ELF linker, which disables
 353   production of copy relocs.  Warning: using this option may result in
 354   non-sharable applications.
 355
 356 * Support for -z combreloc in the ELF linker, which puts dynamic
 357   relocations against the same symbol together, so that dynamic linker
 358   can use an one-entry symbol lookup cache.
 359
 360 * Support for ELF SHF_MERGE section merging, by Jakub Jelinek.
 361
 362 Changes in version 2.11:
 363
 364 * Support for AMD x86-64 architecture, by Jan Hubicka, SuSE Labs.
 365
 366 * Support added for eliminating duplicate DWARF2 debug information by
 367   having the compiler generate the information in sections called
 368   .gnu.linkonce.wi.XXXX where XXXX is a checksum for the contents.  The
 369   linker then merges these sections together into the normal .debug_info
 370   section.
 371
 372 * The native ELF linker now searches the directories in DT_RUNPATH or
 373   DT_RPATH of a shared library for shared libraries needed by it.
 374
 375 * TI C54x support, by Timothy Wall.
 376
 377 * Added command line switch --section-start to set the start address of any
 378   specified section.
 379
 380 * Added ability to emit full relocation information in linked executables,
 381   enabled by --emit-relocs.  Some post-linkage optimization tools need
 382   this information in order to be able to correctly identify and perform
 383   symbol relative addressing in the event of changes in section contents
 384   (instructions being added or deleted, extending data sections, etc.)
 385
 386 * Support for i860, by Jason Eckhardt (preliminary, alpha quality).
 387
 388 * Support for CRIS (Axis Communications ETRAX series).
 389
 390 * Support for PDP-11 and 2.11BSD a.out format, by Lars Brinkhoff.
 391
 392 Changes in version 2.10:
 393
 394 * Added AT> to the linker script language to allow load-time allocation of
 395   sections into regions.
 396
 397 * Added garbage collection of unused sections, enabled by --gc-sections.
 398   It does require a bit of backend support; currently implemented are
 399   arm-elf, avr-elf, d10v-elf, fr30-elf, i386-elf, m32r-elf, m68k-elf,
 400   mcore-elf, mips-elf, mn10300-elf, ppc-elf, sh-elf, sparc-elf, and v850-elf.
 401   Others will ignore the option.
 402
 403 * Added SORT to the linker script language to permit sorting sections by file
 404   name or section name.
 405
 406 * Added EXTERN to the linker script language as an equivalent to the -u
 407   command-line option.
 408
 409 * Added ASSERT to the linker script language.
 410
 411 * Added EXCLUDE_FILE to the linker script language for further control over
 412   wildcard file names.
 413
 414 * Added -O option to optimize linker output (as of this writing, this only
 415   affects ELF shared library generation).
 416
 417 * The -e option now accepts a number as well as a symbol name.
 418
 419 * Added --no-undefined option to disallow undefined symbols when creating a
 420   shared library.
 421
 422 * The linker now issues a warning, not an error, for an undefined symbol when
 423   using -Bsymbolic; use the new --no-undefined option to get the old
 424   behaviour.
 425
 426 * Added --demangle and --no-demangle options.
 427
 428 Changes in version 2.9:
 429
 430 * Added SQUAD to the linker script language.
 431
 432 * New option --no-warn-mismatch.
 433
 434 * The MEMORY command now parses the attributes to determine where sections that
 435   are not placed in a specific memory region are placed.
 436
 437 Changes in version 2.8:
 438
 439 * Linker scripts may now contain shell wildcard characters for file and section
 440   names.
 441
 442 * The linker now supports symbol versions in ELF.
 443
 444 * The NOCROSSREFS command was added to the linker script language.
 445
 446 * The LOADADDR expression was added to the linker script language.
 447
 448 * MAX and MIN functions were added to the linker script language.
 449
 450 * The OVERLAY construct was added to the linker script language.
 451
 452 * New option --warn-section-align to warn when the address of an output section
 453   changes due to alignment of an input section.
 454
 455 * New options --filter/-F and --auxiliary/-f.
 456
 457 Changes in version 2.7:
 458
 459 * New option --cref to print out a cross reference table.
 460
 461 * New option --wrap SYMBOL.
 462
 463 * New option --no-whole-archive, to turn off the effect of --whole-archive.
 464
 465 * Input sections assigned to the output section /DISCARD/ in the linker script
 466   are not included in the output file.
 467
 468 * The SunOS and ELF linkers now merge stabs debugging information which uses
 469   the N_BINCL and N_EINCL stab types.  This reduces the amount of debugging
 470   information generated.
 471
 472 Changes in version 2.6:
 473
 474 * When an ELF section name is representable as a C identifier (this is not true
 475 of most ELF section names), the linker will automatically define symbols
 476 __start_SECNAME and __stop_SECNAME, where SECNAME is the section name, at the
 477 beginning and the end of the section.  This is used by glibc.
 478
 479   Addendum: Current versions of the linker (at least for version 2.18 onwards
 480 and possibly much earlier as well) place two restrictions on this feature:  The
 481 symbols are only implemented for orphaned sections, not for explicitly placed
 482 sections and they are PROVIDEd rather than being defined.
 483
 484 * When an ELF section named .gnu.warning is encountered in an input file, the
 485 contents of the section are displayed as an error message, and the section is
 486 not copied into the output file.  This is used by glibc.
 487
 488 * When an ELF section named .gnu.warning.SYMBOL is encountered in an input
 489 file, and the symbol SYMBOL is referenced by some object file, the contents of
 490 the section are displayed as an error message.  The section is not copied into
 491 the output file, unless doing a relocatable or shared link.  This is used by
 492 glibc.
 493
 494 * New options -split-by-reloc and -split-by-file.
 495
 496 * The linker now supports linking PIC compiled code on SPARC SunOS.  It can
 497 also create SPARC SunOS shared libraries, and, like the native SunOS linker,
 498 will do so whenever there is an undefined symbol in the link and neither the -e
 499 nor the -r option was used.
 500
 501 * The -rpath option may be used on SunOS to set the list of directories to be
 502 searched at run time.  This overrides the default of building the list from the
 503 -L options.
 504
 505 * The COFF linker now combines debugging information for structs, unions, and
 506 enums, so that even if the same type is defined in multiple input files it will
 507 only be defined once in the output file.  The --traditional-format switch will
 508 prevent this optimization.
 509
 510 Changes in version 2.5:
 511
 512 * The linker now supports linking against SunOS shared libraries.  It still can
 513 not link SunOS PIC (Position Independent Code) files, so it can not be used to
 514 generate shared libraries.
 515
 516 * The linker now supports linking against ELF shared libraries for the i386
 517 (UnixWare) and SPARC (Solaris).  It can also link ELF PIC files, and can be
 518 used to generate shared libraries.  Shared library generation is not well
 519 tested; please report any problems encountered.  The linker is now enabled for
 520 Solaris again.
 521
 522 * Eric Youngdale has contributed Linux support code, including linking against
 523 Linux a.out shared libraries.  The linker produces Linux QMAGIC binaries.
 524
 525 * The ELF backend has been converted to the new linker code.  To use the new
 526 ELF linker, each particular target requires a relocation function.  So far,
 527 this function has been written for i386 (UnixWare), SPARC (Solaris) MIPS (Irix
 528 5), and HPPA ELF targets.
 529
 530 * The -( (--start-group) and -) (--end-group) options have been added to
 531 support searching a group of archives as though they were a single archive.
 532 This can also be used in a linker script, as GROUP ( files ).
 533
 534 * When a file is named on the command line, and the linker does not recognize
 535 it as an object file, the linker will now treat the file as a linker script
 536 file.  A linker script named in this way augments, but does not replace, the
 537 default linker script.
 538
 539 * The -warn-once option was added.  It causes the linker to only warn once per
 540 undefined symbol, rather than once per reference.
 541
 542 * The COFF backend has been converted to the new linker code.  As with ELF, to
 543 use the new linker, each particular target requires a relocation function.  So
 544 far, this function has been written for the i386, m68k, a29k and SH targets.
 545
 546 * The -V flag was made a synonym for -v, for SVR4 compatibility.  The old -V
 547 behaviour is available via --verbose.
 548
 549 Changes in version 2.4:
 550
 551 * New linker code, by Steve Chamberlain and Ian Taylor.  For a.out and ecoff
 552   formats (so far), this should result in considerable savings in time
 553   and memory used while linking; slightly poorer performance than
 554   before for formats not converted yet.
 555
 556 * Command-line parsing is no longer done with flex.  This means
 557   oddball characters in filenames won't get treated as argument
 558   separators.
 559
 560 * HP-PA ELF support, by Jeff Law.  (No SOM support yet.)
 561
 562 * Mach i386 support, by David Mackenzie.
 563
 564 * Irix 4 shared libraries are now supported (Irix 5 uses ELF, and ELF shared
 565   libraries are not yet supported).
 566
 567 * COFF shared libraries (as on SCO) should work as well.
 568
 569 * The linker is disabled for Solaris.  (Actually, it was in 2.3 also, I just
 570   forgot to note it.)  Some of their C library routines don't work when
 571   statically linked, and the GNU linker doesn't support dynamic linking yet.
 572
 573 Changes in version 2.3:
 574
 575 * Weak symbols are now supported.
 576
 577 * ELF support has been added.  The linker has been bootstrapped on
 578   UnixWare and Solaris.
 579
 580 * Alpha OSF/1 support has been added (non dynamic linking only).
 581
 582 Changes in version 2.2:
 583
 584 * The `bfd' library has been updated to reduce a.out-format string
 585   table size.  The effect of this is that files linked from many input
 586   files with duplicate symbols (`-g' debugging records, or identical
 587   static symbols) should be much smaller.
 588
 589 Changes in version 2.1:
 590
 591 * The ld -ySYMBOL flag (to trace references to SYMBOL) is now implemented.
 592
 593 * There is now support for writing ECOFF files, so ld and the
 594   other utilities should work on Risc/Ultrix and Irix.
 595
 596 \f
 597 Copyright (C) 2012-2015 Free Software Foundation, Inc.
 598
 599 Copying and distribution of this file, with or without modification,
 600 are permitted in any medium without royalty provided the copyright
 601 notice and this notice are preserved.
 602
 603 Local variables:
 604 fill-column: 79
 605 End: