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