ld/NEWS

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