ld/NEWS

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