ld/NEWS

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