ld/NEWS

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