ld/NEWS

   1 -*- text -*-
   2
   3 * Add support for the ARC EM/HS, and ARC600/700 architectures.
   4
   5 * Experimental support for linker garbage collection (--gc-sections)
   6   has been enabled for COFF and PE based targets.
   7
   8 * New command line option for ELF targets to compress DWARF debug
   9   sections, --compress-debug-sections=[none|zlib|zlib-gnu|zlib-gabi].
  10
  11 * New command line option, --orphan-handling=[place|warn|error|discard], to
  12   adjust how orphan sections are handled.  The default is 'place' which gives
  13   the current behaviour, 'warn' and 'error' issue a warning or error
  14   respectively when orphan sections are found, and 'discard' will discard all
  15   orphan sections.
  16
  17 * Add support for LLVM plugin.
  18
  19 * Add --print-memory-usage option to report memory blocks usage.
  20
  21 * Add --require-defined option, it's like --undefined except the new symbol
  22   must be defined by the end of the link.
  23
  24 Changes in 2.25:
  25
  26 * PE binaries now once again contain real timestamps by default.  To disable
  27   the inclusion of a timestamp in a PE binary, use the --no-insert-timestamp
  28   command line option.
  29
  30 * Replace support for openrisc and or32 with support for or1k.
  31
  32 * Add support for the --build-id command line option to COFF based targets.
  33
  34 * x86/x86_64 pe-coff now supports the --build-id option.
  35
  36 * Add support for the Andes NDS32.
  37
  38 Changes in 2.24:
  39
  40 * Add LOG2CEIL() builtin function to the linker script language
  41
  42 * Add support for the Texas Instruments MSP430X processor.
  43
  44 * Add support for Altera Nios II.
  45
  46 * Add support for the V850E3V5 architecture.
  47
  48 * Add support for the Imagination Technologies Meta processor.
  49
  50 * --enable-new-dtags no longer generates old dtags in addition to new dtags.
  51
  52 * Remove linker support for MIPS ECOFF targets.
  53
  54 * Add ALIGN_WITH_INPUT to the linker script language to force the alignment of
  55   an output section to use the maximum alignment of all its input sections.
  56
  57 Changes in 2.23:
  58
  59 * Enable compressed debug section feature for x86/x86_64 pe-coff.
  60
  61 * Add support for the 64-bit ARM architecture: AArch64.
  62
  63 * Added SORT_NONE to the linker script language to disable section sorting.
  64
  65 * Add a linker-provided symbol when producing ELF output, '__ehdr_start'
  66   to point to the ELF file header (and nearby program headers) in the
  67   program's memory image.
  68
  69 * Add support for S12X processor.
  70
  71 * Add support for the VLE extension to the PowerPC architecture.
  72
  73 * Add support for the Freescale XGATE architecture.
  74
  75 * Add option -f FILE on AIX (for response file).
  76
  77 * Add support for the Renesas RL78 architecture.
  78
  79 * Add support for the Adapteva EPIPHANY architecture.
  80
  81 Changes in 2.22:
  82
  83 * --copy-dt-needed-entries is no longer enabled by default.  Instead
  84   --no-copy-dt-needed-entries is the default.
  85
  86 * INPUT_SECTION_FLAGS has been added to the linker script language
  87   to allow selection of input sections by section header section flags.
  88
  89 * Add support for the Tilera TILEPro and TILE-Gx architectures.
  90
  91 * Added SORT_BY_INIT_PRIORITY to the linker script language to permit
  92   sorting sections by numerical value of the GCC init_priority attribute
  93   encoded in the section name.
  94
  95 Changes in 2.21:
  96
  97 * Linker script expression evaluation is somewhat more sane.  This may
  98   break scripts that depend on quirks of the old expression evaluation.
  99
 100 * Turn off underscoring for x86_64 PE+-COFF targets.  For old behavior the
 101   option --enable-leading-mingw64-underscores can be used on configure of
 102   bfd.
 103
 104 * Add support for the TMS320C6000 (TI C6X) processor family.
 105
 106 * --add-needed renamed to --copy-dt-needed-entries in order to avoid confusion
 107   with --as-needed option.
 108
 109 * Extend .def file syntax by '== <ID>' for imports and exports. This allows
 110   to alias the import/export table name written in PE image.
 111
 112 * Add --exclude-all-symbols option to PE based linkers.  This prevents all
 113   symbols from automatically being exported.
 114
 115 * Add support for the Renesas RX processor.
 116
 117 * Add support for alpha-vms target.
 118
 119 Changes in 2.20:
 120
 121 * GNU/Linux targets now support the STB_GNU_UNIQUE symbol binding.  This is a
 122   GNU extension to the standard set of ELF symbol bindings.  The binding will
 123   be passed on to the dynamic linker which will make sure that in the entire
 124   process there is just one symbol with the given name and type in use.
 125
 126 * PE targets now support a GNU extension to allow the alignment of common
 127   common symbols to be specified.  This support uses custom options in
 128   the .drectve section, which will be disregarded by the native tools.
 129
 130 * PE targets now add primitive support for ELF version scripts; symbols
 131   are not versioned, but the local and global symbol visibility directives
 132   are respected when filtering symbols in auto-export mode.
 133
 134 * New option --no-export-dynamic to undo the effect of the -E and
 135   --export-dynamic options.
 136
 137 * ELF: --warn-alternate-em option to warn if an object has alternate
 138   ELF machine code.
 139
 140 * New script function REGION_ALIAS to add alias names to memory regions.
 141
 142 * PE targets no longer make use of the long section names PE extension to
 143   the COFF format when generating executable images, by default.  The old
 144   (slightly non-conformant) behaviour can still be invoked by using the
 145   new '--enable-long-section-names' command-line option.  It is also enabled
 146   automatically in the presence of un-stripped debug information, as GDB
 147   needs to be able to find the debug info sections by their full names.
 148
 149 * For GNU/Linux systems the linker will now avoid processing any relocations
 150   made against symbols of the STT_GNU_IFUNC type and instead emit them into
 151   the resulting binary for processing by the loader.
 152
 153 * --as-needed now links in a dynamic library if it satisfies undefined
 154   symbols in regular objects, or in other dynamic libraries.  In the
 155   latter case the library is not linked if it is found in a DT_NEEDED
 156   entry of one of the libraries already linked.
 157
 158 * Add a new command line option, -Ttext-segment ADDR, for ELF targets
 159   to set the address of the first byte of the text segment.
 160
 161 * Add support for Sunplus score architecture.
 162
 163 * Add new option --use-nul-prefixed-import-tables to ld for PE targets to
 164   allow fallback to old import table generation with null element prefix.
 165
 166 * Windows PE systems now support a new --exclude-modules-for-implib option,
 167   allowing users to partition object files and archive members between a DLL
 168   and its associated import library as they are generated during linking.
 169
 170 * Add support for Lattice Mico32 (lm32) architecture.
 171
 172 * Add CR16 ELF --embedded-relocs (used to embedded relocations into binaries
 173   for Embedded-PIC code) option.
 174
 175 * Add to the PE/PE+ targets the support of two different kinds of
 176   pseudo-relocations.  They can be selected by the switches
 177   --enable-runtime-pseudo-reloc-v1 and --enable-runtime-pseudo-reloc-v2.
 178   For the switch --enable-runtime-pseudo-reloc it uses for 32-bit
 179   runtime pseudo relocation version one, for 64-bit the version two.
 180
 181 Changes in 2.19:
 182
 183 * Linker scripts support a new INSERT command that makes it easier to
 184   augment the default script.
 185
 186 * Linker script input section filespecs may now specify a file within an
 187   archive by writing "archive:file".
 188
 189 * The --sort-common switch now has an optional argument which specifies the
 190   direction of sorting.
 191
 192 * The M68K linker now supports multiple GOT generation schemes controlled via
 193   the --got=<type> command line option.
 194
 195 * The ARM EABI linker will now generate stubs for function calls to symbols
 196   that are too far away.  The placement of the stubs is controlled by a new
 197   linker command line option: --stub-group-size=N.
 198
 199 Changes in 2.18:
 200
 201 * Linker sources now released under version 3 of the GNU General Public
 202   License.
 203
 204 * ELF: New --build-id option to generate a unique per-binary identifier
 205   embedded in a note section.
 206
 207 * Added support for National Semicondutor CompactRISC (ie CR16) target.
 208
 209 * -l:foo now searches the library path for a filename called foo,
 210   without converting it to libfoo.a or libfoo.so.
 211
 212 * Add a new command line option '--default-script=FILE' or '-dT FILE'
 213   which specifies a replacement for the built in, default linker
 214   script.
 215
 216 * ELF: Add -Bsymbolic-functions, --dynamic-list-cpp-new, which puts C++
 217   operator new and delete on the dynamic list, and --dynamic-list-data,
 218   builtin list for --dynamic-list, which puts global data symbols on the
 219   dynamic list.
 220
 221 * Add support for x86_64 PE+ target.
 222
 223 * Add support for Score target.
 224
 225 * ELF: Add --dynamic-list option to specify a list of global symbols
 226   whose references shouldn't be bound to the definition within the
 227   shared library, or a list of symbols which should be added to the
 228   symbol table in the executable.
 229
 230 * The default output section LMA has changed for allocatable sections from
 231   being equal to VMA, to keeping the difference between LMA and VMA the same as
 232   the previous output section in the same region.  This is a more useful
 233   default when using overlays and other cases where you specify an LMA
 234   differing from the VMA for some sections.
 235
 236 * New switch: --print-gc-sections to list any sections removed by garabge
 237   collection.
 238
 239 * ARM: Added --vfp11-denorm-fix option to work around an erratum in current
 240   VFP11 coprocessors.
 241
 242 Changes in 2.17:
 243
 244 * Support for the Infineon XC16X has been added by KPIT Cummins Infosystems.
 245
 246 * Modify the Linux linker search order to better match ld.so search order.
 247   Look for DT_NEEDED libraries in paths specified by ld.so.conf before
 248   searching the default directories, rather than vice versa.
 249   Use $prefix/etc/ld.so.conf if it exists, otherwise /etc/ld.so.conf.
 250
 251 * PE-COFF: Forward exports from DLL's can now be specified in .def files
 252   passed directly to ld.
 253
 254 * Support for the Z80 processor family has been added.
 255
 256 * Add support for the "@<file>" syntax to the command line, so that extra
 257   switches can be read from <file>.
 258
 259 Changes in 2.16:
 260
 261 * Support for the R_ARM_V4BX relocation as defined in the ARM AAELF
 262   specification has been added via the --fix-v4bx command-line option.
 263
 264 * New linker script construct AS_NEEDED(), which sets the --as-needed flag
 265   for input files listed inside of it.
 266
 267 * A new command-line option, --sysroot, can be used to override the
 268   default sysroot location.  It only applies to toolchains that were
 269   configured using --with-sysroot.
 270
 271 * New linker script functions: ORIGIN() and LENGTH() which return information
 272   about a specified memory region.
 273
 274 * Port to MAXQ processor contributed by HCL Tech.
 275
 276 * Added SEGMENT_START to the linker script language to permit the user to
 277   override the base address for a segment from the command-line.
 278
 279 * ELF: --warn-shared-textrel option to warn if adding a DT_TEXTREL to a shared
 280   object.
 281
 282 * Added SORT_BY_NAME and SORT_BY_ALIGNMENT to the linker script
 283   language to permit sorting sections by section name or section
 284   maximum alignment.
 285
 286 * Added a new linker command line switch, --sort-section name|alignment,
 287   to sort sections by section name or maximum alignment.
 288
 289 * ELF: --add-needed/--no-add-needed options to control if a DT_NEEDED tag
 290   should be added when a shared library comes from DT_NEEDED tags.
 291
 292 * Support for the crx-elf target added.
 293
 294 * Support for the sh-symbianelf target added.
 295
 296 * A new linker command line switch has been added which allows the hash table
 297   size to be set to a suitable prime value near to its argument.  This switch
 298   is --hash-size=<NUMBER>.  Also if the switch --reduce-memory-overheads is
 299   used, and --hash-size has not been used, then the default value will be set
 300   to 1021.
 301
 302 * Linker map files are now generated with an O(N) algorithm for finding symbols
 303   that are defined in each section.  This uses about 40% more memory for
 304   symbols than the old O(N^2) algorithm.  You can use the new
 305   --reduce-memory-overheads option to select the old algorithm; this option
 306   might also be used in the future to select similar tradeoffs.
 307
 308 Changes in 2.15:
 309
 310 * ELF: --as-needed/--no-as-needed options to control if a DT_NEEDED tag should
 311   be added only when a shared library is referenced.
 312
 313 * PE: --large-address-aware option to indicate executables support virtual
 314   addresses greater than 2 gigabytes.
 315
 316 * DWARF 2 support for i386pe added.
 317
 318 * The linker script operator DEFINED() will now yield 1 only for a symbol that
 319   is defined before the statement where DEFINED is used.
 320
 321 * The MIPS --embedded-relocs (used to embed relocations into binaries for
 322   Embedded-PIC code) is deprecated and will be removed in a future release.
 323
 324 * cr16c support added by NSC.
 325
 326 * m32r Linux (ELF) support added by Renesas.
 327
 328 * Improved linker's handling of unresolved symbols.  The switch
 329   --unresolved-symbols=<method> has been added to tell the linker when it
 330   should report them and the switch --warn-unresolved-symbols has been added to
 331   make reports be issued as warning messages rather than errors.
 332
 333 Changes in 2.14:
 334
 335 * Added support for Xtensa architecture.
 336
 337 * Added --with-sysroot configure switch to specify a target system root, for
 338   linking against a target filesystem image.
 339
 340 * Added --accept-unknown-linker-format to restore old linker behaviour (pre
 341   2.14) of silently accepting and linking in any files in an unknown binary
 342   file format.
 343
 344 * Added --no-omagic to undo the effects of the -N option.
 345
 346 * Support for Texas Instruments TMS320C4x and TMS320C3x series of
 347   DSP's contributed by Michael Hayes and Svein E. Seldal.
 348
 349 * Added --with-lib-path configure switch to specify default value for
 350   LIB_PATH.
 351
 352 * ARM port to QNX operating system added by Graeme Peterson.
 353
 354 * IP2K support added by Denis Chertykov.
 355
 356 Changes in 2.13:
 357
 358 * Support for the Fujitsu FRV architecture added by Red Hat. Models for FR400
 359   and FR500 included.
 360
 361 Changes in version 2.13:
 362
 363 * DEC VAX ELF support, by Matt Thomas.
 364
 365 Changes in version 2.12:
 366
 367 * Support for Don Knuth's MMIX, by Hans-Peter Nilsson.
 368
 369 * Support for the OpenRISC 32-bit embedded processor by OpenCores.
 370
 371 * Support for -z nocopyreloc in the x86 ELF linker, which disables
 372   production of copy relocs.  Warning: using this option may result in
 373   non-sharable applications.
 374
 375 * Support for -z combreloc in the ELF linker, which puts dynamic
 376   relocations against the same symbol together, so that dynamic linker
 377   can use an one-entry symbol lookup cache.
 378
 379 * Support for ELF SHF_MERGE section merging, by Jakub Jelinek.
 380
 381 Changes in version 2.11:
 382
 383 * Support for AMD x86-64 architecture, by Jan Hubicka, SuSE Labs.
 384
 385 * Support added for eliminating duplicate DWARF2 debug information by
 386   having the compiler generate the information in sections called
 387   .gnu.linkonce.wi.XXXX where XXXX is a checksum for the contents.  The
 388   linker then merges these sections together into the normal .debug_info
 389   section.
 390
 391 * The native ELF linker now searches the directories in DT_RUNPATH or
 392   DT_RPATH of a shared library for shared libraries needed by it.
 393
 394 * TI C54x support, by Timothy Wall.
 395
 396 * Added command line switch --section-start to set the start address of any
 397   specified section.
 398
 399 * Added ability to emit full relocation information in linked executables,
 400   enabled by --emit-relocs.  Some post-linkage optimization tools need
 401   this information in order to be able to correctly identify and perform
 402   symbol relative addressing in the event of changes in section contents
 403   (instructions being added or deleted, extending data sections, etc.)
 404
 405 * Support for i860, by Jason Eckhardt (preliminary, alpha quality).
 406
 407 * Support for CRIS (Axis Communications ETRAX series).
 408
 409 * Support for PDP-11 and 2.11BSD a.out format, by Lars Brinkhoff.
 410
 411 Changes in version 2.10:
 412
 413 * Added AT> to the linker script language to allow load-time allocation of
 414   sections into regions.
 415
 416 * Added garbage collection of unused sections, enabled by --gc-sections.
 417   It does require a bit of backend support; currently implemented are
 418   arm-elf, avr-elf, d10v-elf, fr30-elf, i386-elf, m32r-elf, m68k-elf,
 419   mcore-elf, mips-elf, mn10300-elf, ppc-elf, sh-elf, sparc-elf, and v850-elf.
 420   Others will ignore the option.
 421
 422 * Added SORT to the linker script language to permit sorting sections by file
 423   name or section name.
 424
 425 * Added EXTERN to the linker script language as an equivalent to the -u
 426   command-line option.
 427
 428 * Added ASSERT to the linker script language.
 429
 430 * Added EXCLUDE_FILE to the linker script language for further control over
 431   wildcard file names.
 432
 433 * Added -O option to optimize linker output (as of this writing, this only
 434   affects ELF shared library generation).
 435
 436 * The -e option now accepts a number as well as a symbol name.
 437
 438 * Added --no-undefined option to disallow undefined symbols when creating a
 439   shared library.
 440
 441 * The linker now issues a warning, not an error, for an undefined symbol when
 442   using -Bsymbolic; use the new --no-undefined option to get the old
 443   behaviour.
 444
 445 * Added --demangle and --no-demangle options.
 446
 447 Changes in version 2.9:
 448
 449 * Added SQUAD to the linker script language.
 450
 451 * New option --no-warn-mismatch.
 452
 453 * The MEMORY command now parses the attributes to determine where sections that
 454   are not placed in a specific memory region are placed.
 455
 456 Changes in version 2.8:
 457
 458 * Linker scripts may now contain shell wildcard characters for file and section
 459   names.
 460
 461 * The linker now supports symbol versions in ELF.
 462
 463 * The NOCROSSREFS command was added to the linker script language.
 464
 465 * The LOADADDR expression was added to the linker script language.
 466
 467 * MAX and MIN functions were added to the linker script language.
 468
 469 * The OVERLAY construct was added to the linker script language.
 470
 471 * New option --warn-section-align to warn when the address of an output section
 472   changes due to alignment of an input section.
 473
 474 * New options --filter/-F and --auxiliary/-f.
 475
 476 Changes in version 2.7:
 477
 478 * New option --cref to print out a cross reference table.
 479
 480 * New option --wrap SYMBOL.
 481
 482 * New option --no-whole-archive, to turn off the effect of --whole-archive.
 483
 484 * Input sections assigned to the output section /DISCARD/ in the linker script
 485   are not included in the output file.
 486
 487 * The SunOS and ELF linkers now merge stabs debugging information which uses
 488   the N_BINCL and N_EINCL stab types.  This reduces the amount of debugging
 489   information generated.
 490
 491 Changes in version 2.6:
 492
 493 * When an ELF section name is representable as a C identifier (this is not true
 494 of most ELF section names), the linker will automatically define symbols
 495 __start_SECNAME and __stop_SECNAME, where SECNAME is the section name, at the
 496 beginning and the end of the section.  This is used by glibc.
 497
 498   Addendum: Current versions of the linker (at least for version 2.18 onwards
 499 and possibly much earlier as well) place two restrictions on this feature:  The
 500 symbols are only implemented for orphaned sections, not for explicitly placed
 501 sections and they are PROVIDEd rather than being defined.
 502
 503 * When an ELF section named .gnu.warning is encountered in an input file, the
 504 contents of the section are displayed as an error message, and the section is
 505 not copied into the output file.  This is used by glibc.
 506
 507 * When an ELF section named .gnu.warning.SYMBOL is encountered in an input
 508 file, and the symbol SYMBOL is referenced by some object file, the contents of
 509 the section are displayed as an error message.  The section is not copied into
 510 the output file, unless doing a relocatable or shared link.  This is used by
 511 glibc.
 512
 513 * New options -split-by-reloc and -split-by-file.
 514
 515 * The linker now supports linking PIC compiled code on SPARC SunOS.  It can
 516 also create SPARC SunOS shared libraries, and, like the native SunOS linker,
 517 will do so whenever there is an undefined symbol in the link and neither the -e
 518 nor the -r option was used.
 519
 520 * The -rpath option may be used on SunOS to set the list of directories to be
 521 searched at run time.  This overrides the default of building the list from the
 522 -L options.
 523
 524 * The COFF linker now combines debugging information for structs, unions, and
 525 enums, so that even if the same type is defined in multiple input files it will
 526 only be defined once in the output file.  The --traditional-format switch will
 527 prevent this optimization.
 528
 529 Changes in version 2.5:
 530
 531 * The linker now supports linking against SunOS shared libraries.  It still can
 532 not link SunOS PIC (Position Independent Code) files, so it can not be used to
 533 generate shared libraries.
 534
 535 * The linker now supports linking against ELF shared libraries for the i386
 536 (UnixWare) and SPARC (Solaris).  It can also link ELF PIC files, and can be
 537 used to generate shared libraries.  Shared library generation is not well
 538 tested; please report any problems encountered.  The linker is now enabled for
 539 Solaris again.
 540
 541 * Eric Youngdale has contributed Linux support code, including linking against
 542 Linux a.out shared libraries.  The linker produces Linux QMAGIC binaries.
 543
 544 * The ELF backend has been converted to the new linker code.  To use the new
 545 ELF linker, each particular target requires a relocation function.  So far,
 546 this function has been written for i386 (UnixWare), SPARC (Solaris) MIPS (Irix
 547 5), and HPPA ELF targets.
 548
 549 * The -( (--start-group) and -) (--end-group) options have been added to
 550 support searching a group of archives as though they were a single archive.
 551 This can also be used in a linker script, as GROUP ( files ).
 552
 553 * When a file is named on the command line, and the linker does not recognize
 554 it as an object file, the linker will now treat the file as a linker script
 555 file.  A linker script named in this way augments, but does not replace, the
 556 default linker script.
 557
 558 * The -warn-once option was added.  It causes the linker to only warn once per
 559 undefined symbol, rather than once per reference.
 560
 561 * The COFF backend has been converted to the new linker code.  As with ELF, to
 562 use the new linker, each particular target requires a relocation function.  So
 563 far, this function has been written for the i386, m68k, a29k and SH targets.
 564
 565 * The -V flag was made a synonym for -v, for SVR4 compatibility.  The old -V
 566 behaviour is available via --verbose.
 567
 568 Changes in version 2.4:
 569
 570 * New linker code, by Steve Chamberlain and Ian Taylor.  For a.out and ecoff
 571   formats (so far), this should result in considerable savings in time
 572   and memory used while linking; slightly poorer performance than
 573   before for formats not converted yet.
 574
 575 * Command-line parsing is no longer done with flex.  This means
 576   oddball characters in filenames won't get treated as argument
 577   separators.
 578
 579 * HP-PA ELF support, by Jeff Law.  (No SOM support yet.)
 580
 581 * Mach i386 support, by David Mackenzie.
 582
 583 * Irix 4 shared libraries are now supported (Irix 5 uses ELF, and ELF shared
 584   libraries are not yet supported).
 585
 586 * COFF shared libraries (as on SCO) should work as well.
 587
 588 * The linker is disabled for Solaris.  (Actually, it was in 2.3 also, I just
 589   forgot to note it.)  Some of their C library routines don't work when
 590   statically linked, and the GNU linker doesn't support dynamic linking yet.
 591
 592 Changes in version 2.3:
 593
 594 * Weak symbols are now supported.
 595
 596 * ELF support has been added.  The linker has been bootstrapped on
 597   UnixWare and Solaris.
 598
 599 * Alpha OSF/1 support has been added (non dynamic linking only).
 600
 601 Changes in version 2.2:
 602
 603 * The `bfd' library has been updated to reduce a.out-format string
 604   table size.  The effect of this is that files linked from many input
 605   files with duplicate symbols (`-g' debugging records, or identical
 606   static symbols) should be much smaller.
 607
 608 Changes in version 2.1:
 609
 610 * The ld -ySYMBOL flag (to trace references to SYMBOL) is now implemented.
 611
 612 * There is now support for writing ECOFF files, so ld and the
 613   other utilities should work on Risc/Ultrix and Irix.
 614
 615 \f
 616 Copyright (C) 2012-2015 Free Software Foundation, Inc.
 617
 618 Copying and distribution of this file, with or without modification,
 619 are permitted in any medium without royalty provided the copyright
 620 notice and this notice are preserved.
 621
 622 Local variables:
 623 fill-column: 79
 624 End: