ld/NEWS

   1 -*- text -*-
   2
   3 * Add support for the Andes NDS32.
   4
   5 Changes in 2.24:
   6
   7 * Add LOG2CEIL() builtin function to the linker script language
   8
   9 * Add support for the Texas Instruments MSP430X processor.
  10
  11 * Add support for Altera Nios II.
  12
  13 * Add support for the V850E3V5 architecture.
  14
  15 * Add support for the Imagination Technologies Meta processor.
  16
  17 * --enable-new-dtags no longer generates old dtags in addition to new dtags.
  18
  19 * Remove linker support for MIPS ECOFF targets.
  20
  21 * Add ALIGN_WITH_INPUT to the linker script language to force the alignment of
  22   an output section to use the maximum alignment of all its input sections.
  23
  24 Changes in 2.23:
  25
  26 * Enable compressed debug section feature for x86/x86_64 pe-coff.
  27
  28 * Add support for the 64-bit ARM architecture: AArch64.
  29
  30 * Added SORT_NONE to the linker script language to disable section sorting.
  31
  32 * Add a linker-provided symbol when producing ELF output, '__ehdr_start'
  33   to point to the ELF file header (and nearby program headers) in the
  34   program's memory image.
  35
  36 * Add support for S12X processor.
  37
  38 * Add support for the VLE extension to the PowerPC architecture.
  39
  40 * Add support for the Freescale XGATE architecture.
  41
  42 * Add option -f FILE on AIX (for response file).
  43
  44 * Add support for the Renesas RL78 architecture.
  45
  46 * Add support for the Adapteva EPIPHANY architecture.
  47
  48 Changes in 2.22:
  49
  50 * --copy-dt-needed-entries is no longer enabled by default.  Instead
  51   --no-copy-dt-needed-entries is the default.
  52
  53 * INPUT_SECTION_FLAGS has been added to the linker script language
  54   to allow selection of input sections by section header section flags.
  55
  56 * Add support for the Tilera TILEPro and TILE-Gx architectures.
  57
  58 * Added SORT_BY_INIT_PRIORITY to the linker script language to permit
  59   sorting sections by numerical value of the GCC init_priority attribute
  60   encoded in the section name.
  61
  62 Changes in 2.21:
  63
  64 * Linker script expression evaluation is somewhat more sane.  This may
  65   break scripts that depend on quirks of the old expression evaluation.
  66
  67 * Turn off underscoring for x86_64 PE+-COFF targets.  For old behavior the
  68   option --enable-leading-mingw64-underscores can be used on configure of
  69   bfd.
  70
  71 * Add support for the TMS320C6000 (TI C6X) processor family.
  72
  73 * --add-needed renamed to --copy-dt-needed-entries in order to avoid confusion
  74   with --as-needed option.
  75
  76 * Extend .def file syntax by '== <ID>' for imports and exports. This allows
  77   to alias the import/export table name written in PE image.
  78
  79 * Add --exclude-all-symbols option to PE based linkers.  This prevents all
  80   symbols from automatically being exported.
  81
  82 * Add support for the Renesas RX processor.
  83
  84 * Add support for alpha-vms target.
  85
  86 Changes in 2.20:
  87
  88 * GNU/Linux targets now support the STB_GNU_UNIQUE symbol binding.  This is a
  89   GNU extension to the standard set of ELF symbol bindings.  The binding will
  90   be passed on to the dynamic linker which will make sure that in the entire
  91   process there is just one symbol with the given name and type in use.
  92
  93 * PE targets now support a GNU extension to allow the alignment of common
  94   common symbols to be specified.  This support uses custom options in
  95   the .drectve section, which will be disregarded by the native tools.
  96
  97 * PE targets now add primitive support for ELF version scripts; symbols
  98   are not versioned, but the local and global symbol visibility directives
  99   are respected when filtering symbols in auto-export mode.
 100
 101 * New option --no-export-dynamic to undo the effect of the -E and
 102   --export-dynamic options.
 103
 104 * ELF: --warn-alternate-em option to warn if an object has alternate
 105   ELF machine code.
 106
 107 * New script function REGION_ALIAS to add alias names to memory regions.
 108
 109 * PE targets no longer make use of the long section names PE extension to
 110   the COFF format when generating executable images, by default.  The old
 111   (slightly non-conformant) behaviour can still be invoked by using the
 112   new '--enable-long-section-names' command-line option.  It is also enabled
 113   automatically in the presence of un-stripped debug information, as GDB
 114   needs to be able to find the debug info sections by their full names.
 115
 116 * For GNU/Linux systems the linker will now avoid processing any relocations
 117   made against symbols of the STT_GNU_IFUNC type and instead emit them into
 118   the resulting binary for processing by the loader.
 119
 120 * --as-needed now links in a dynamic library if it satisfies undefined
 121   symbols in regular objects, or in other dynamic libraries.  In the
 122   latter case the library is not linked if it is found in a DT_NEEDED
 123   entry of one of the libraries already linked.
 124
 125 * Add a new command line option, -Ttext-segment ADDR, for ELF targets
 126   to set the address of the first byte of the text segment.
 127
 128 * Add support for Sunplus score architecture.
 129
 130 * Add new option --use-nul-prefixed-import-tables to ld for PE targets to
 131   allow fallback to old import table generation with null element prefix.
 132
 133 * Windows PE systems now support a new --exclude-modules-for-implib option,
 134   allowing users to partition object files and archive members between a DLL
 135   and its associated import library as they are generated during linking.
 136
 137 * Add support for Lattice Mico32 (lm32) architecture.
 138
 139 * Add CR16 ELF --embedded-relocs (used to embedded relocations into binaries
 140   for Embedded-PIC code) option.
 141
 142 * Add to the PE/PE+ targets the support of two different kinds of
 143   pseudo-relocations.  They can be selected by the switches
 144   --enable-runtime-pseudo-reloc-v1 and --enable-runtime-pseudo-reloc-v2.
 145   For the switch --enable-runtime-pseudo-reloc it uses for 32-bit
 146   runtime pseudo relocation version one, for 64-bit the version two.
 147
 148 Changes in 2.19:
 149
 150 * Linker scripts support a new INSERT command that makes it easier to
 151   augment the default script.
 152
 153 * Linker script input section filespecs may now specify a file within an
 154   archive by writing "archive:file".
 155
 156 * The --sort-common switch now has an optional argument which specifies the
 157   direction of sorting.
 158
 159 * The M68K linker now supports multiple GOT generation schemes controlled via
 160   the --got=<type> command line option.
 161
 162 * The ARM EABI linker will now generate stubs for function calls to symbols
 163   that are too far away.  The placement of the stubs is controlled by a new
 164   linker command line option: --stub-group-size=N.
 165
 166 Changes in 2.18:
 167
 168 * Linker sources now released under version 3 of the GNU General Public
 169   License.
 170
 171 * ELF: New --build-id option to generate a unique per-binary identifier
 172   embedded in a note section.
 173
 174 * Added support for National Semicondutor CompactRISC (ie CR16) target.
 175
 176 * -l:foo now searches the library path for a filename called foo,
 177   without converting it to libfoo.a or libfoo.so.
 178
 179 * Add a new command line option '--default-script=FILE' or '-dT FILE'
 180   which specifies a replacement for the built in, default linker
 181   script.
 182
 183 * ELF: Add -Bsymbolic-functions, --dynamic-list-cpp-new, which puts C++
 184   operator new and delete on the dynamic list, and --dynamic-list-data,
 185   builtin list for --dynamic-list, which puts global data symbols on the
 186   dynamic list.
 187
 188 * Add support for x86_64 PE+ target.
 189
 190 * Add support for Score target.
 191
 192 * ELF: Add --dynamic-list option to specify a list of global symbols
 193   whose references shouldn't be bound to the definition within the
 194   shared library, or a list of symbols which should be added to the
 195   symbol table in the executable.
 196
 197 * The default output section LMA has changed for allocatable sections from
 198   being equal to VMA, to keeping the difference between LMA and VMA the same as
 199   the previous output section in the same region.  This is a more useful
 200   default when using overlays and other cases where you specify an LMA
 201   differing from the VMA for some sections.
 202
 203 * New switch: --print-gc-sections to list any sections removed by garabge
 204   collection.
 205
 206 * ARM: Added --vfp11-denorm-fix option to work around an erratum in current
 207   VFP11 coprocessors.
 208
 209 Changes in 2.17:
 210
 211 * Support for the Infineon XC16X has been added by KPIT Cummins Infosystems.
 212
 213 * Modify the Linux linker search order to better match ld.so search order.
 214   Look for DT_NEEDED libraries in paths specified by ld.so.conf before
 215   searching the default directories, rather than vice versa.
 216   Use $prefix/etc/ld.so.conf if it exists, otherwise /etc/ld.so.conf.
 217
 218 * PE-COFF: Forward exports from DLL's can now be specified in .def files
 219   passed directly to ld.
 220
 221 * Support for the Z80 processor family has been added.
 222
 223 * Add support for the "@<file>" syntax to the command line, so that extra
 224   switches can be read from <file>.
 225
 226 Changes in 2.16:
 227
 228 * Support for the R_ARM_V4BX relocation as defined in the ARM AAELF
 229   specification has been added via the --fix-v4bx command-line option.
 230
 231 * New linker script construct AS_NEEDED(), which sets the --as-needed flag
 232   for input files listed inside of it.
 233
 234 * A new command-line option, --sysroot, can be used to override the
 235   default sysroot location.  It only applies to toolchains that were
 236   configured using --with-sysroot.
 237
 238 * New linker script functions: ORIGIN() and LENGTH() which return information
 239   about a specified memory region.
 240
 241 * Port to MAXQ processor contributed by HCL Tech.
 242
 243 * Added SEGMENT_START to the linker script language to permit the user to
 244   override the base address for a segment from the command-line.
 245
 246 * ELF: --warn-shared-textrel option to warn if adding a DT_TEXTREL to a shared
 247   object.
 248
 249 * Added SORT_BY_NAME and SORT_BY_ALIGNMENT to the linker script
 250   language to permit sorting sections by section name or section
 251   maximum alignment.
 252
 253 * Added a new linker command line switch, --sort-section name|alignment,
 254   to sort sections by section name or maximum alignment.
 255
 256 * ELF: --add-needed/--no-add-needed options to control if a DT_NEEDED tag
 257   should be added when a shared library comes from DT_NEEDED tags.
 258
 259 * Support for the crx-elf target added.
 260
 261 * Support for the sh-symbianelf target added.
 262
 263 * A new linker command line switch has been added which allows the hash table
 264   size to be set to a suitable prime value near to its argument.  This switch
 265   is --hash-size=<NUMBER>.  Also if the switch --reduce-memory-overheads is
 266   used, and --hash-size has not been used, then the default value will be set
 267   to 1021.
 268
 269 * Linker map files are now generated with an O(N) algorithm for finding symbols
 270   that are defined in each section.  This uses about 40% more memory for
 271   symbols than the old O(N^2) algorithm.  You can use the new
 272   --reduce-memory-overheads option to select the old algorithm; this option
 273   might also be used in the future to select similar tradeoffs.
 274
 275 Changes in 2.15:
 276
 277 * ELF: --as-needed/--no-as-needed options to control if a DT_NEEDED tag should
 278   be added only when a shared library is referenced.
 279
 280 * PE: --large-address-aware option to indicate executables support virtual
 281   addresses greater than 2 gigabytes.
 282
 283 * DWARF 2 support for i386pe added.
 284
 285 * The linker script operator DEFINED() will now yield 1 only for a symbol that
 286   is defined before the statement where DEFINED is used.
 287
 288 * The MIPS --embedded-relocs (used to embed relocations into binaries for
 289   Embedded-PIC code) is deprecated and will be removed in a future release.
 290
 291 * cr16c support added by NSC.
 292
 293 * m32r Linux (ELF) support added by Renesas.
 294
 295 * Improved linker's handling of unresolved symbols.  The switch
 296   --unresolved-symbols=<method> has been added to tell the linker when it
 297   should report them and the switch --warn-unresolved-symbols has been added to
 298   make reports be issued as warning messages rather than errors.
 299
 300 Changes in 2.14:
 301
 302 * Added support for Xtensa architecture.
 303
 304 * Added --with-sysroot configure switch to specify a target system root, for
 305   linking against a target filesystem image.
 306
 307 * Added --accept-unknown-linker-format to restore old linker behaviour (pre
 308   2.14) of silently accepting and linking in any files in an unknown binary
 309   file format.
 310
 311 * Added --no-omagic to undo the effects of the -N option.
 312
 313 * Support for Texas Instruments TMS320C4x and TMS320C3x series of
 314   DSP's contributed by Michael Hayes and Svein E. Seldal.
 315
 316 * Added --with-lib-path configure switch to specify default value for
 317   LIB_PATH.
 318
 319 * ARM port to QNX operating system added by Graeme Peterson.
 320
 321 * IP2K support added by Denis Chertykov.
 322
 323 Changes in 2.13:
 324
 325 * Support for the Fujitsu FRV architecture added by Red Hat. Models for FR400
 326   and FR500 included.
 327
 328 Changes in version 2.13:
 329
 330 * DEC VAX ELF support, by Matt Thomas.
 331
 332 Changes in version 2.12:
 333
 334 * Support for Don Knuth's MMIX, by Hans-Peter Nilsson.
 335
 336 * Support for the OpenRISC 32-bit embedded processor by OpenCores.
 337
 338 * Support for -z nocopyreloc in the x86 ELF linker, which disables
 339   production of copy relocs.  Warning: using this option may result in
 340   non-sharable applications.
 341
 342 * Support for -z combreloc in the ELF linker, which puts dynamic
 343   relocations against the same symbol together, so that dynamic linker
 344   can use an one-entry symbol lookup cache.
 345
 346 * Support for ELF SHF_MERGE section merging, by Jakub Jelinek.
 347
 348 Changes in version 2.11:
 349
 350 * Support for AMD x86-64 architecture, by Jan Hubicka, SuSE Labs.
 351
 352 * Support added for eliminating duplicate DWARF2 debug information by
 353   having the compiler generate the information in sections called
 354   .gnu.linkonce.wi.XXXX where XXXX is a checksum for the contents.  The
 355   linker then merges these sections together into the normal .debug_info
 356   section.
 357
 358 * The native ELF linker now searches the directories in DT_RUNPATH or
 359   DT_RPATH of a shared library for shared libraries needed by it.
 360
 361 * TI C54x support, by Timothy Wall.
 362
 363 * Added command line switch --section-start to set the start address of any
 364   specified section.
 365
 366 * Added ability to emit full relocation information in linked executables,
 367   enabled by --emit-relocs.  Some post-linkage optimization tools need
 368   this information in order to be able to correctly identify and perform
 369   symbol relative addressing in the event of changes in section contents
 370   (instructions being added or deleted, extending data sections, etc.)
 371
 372 * Support for i860, by Jason Eckhardt (preliminary, alpha quality).
 373
 374 * Support for CRIS (Axis Communications ETRAX series).
 375
 376 * Support for PDP-11 and 2.11BSD a.out format, by Lars Brinkhoff.
 377
 378 Changes in version 2.10:
 379
 380 * Added AT> to the linker script language to allow load-time allocation of
 381   sections into regions.
 382
 383 * Added garbage collection of unused sections, enabled by --gc-sections.
 384   It does require a bit of backend support; currently implemented are
 385   arm-elf, avr-elf, d10v-elf, fr30-elf, i386-elf, m32r-elf, m68k-elf,
 386   mcore-elf, mips-elf, mn10300-elf, ppc-elf, sh-elf, sparc-elf, and v850-elf.
 387   Others will ignore the option.
 388
 389 * Added SORT to the linker script language to permit sorting sections by file
 390   name or section name.
 391
 392 * Added EXTERN to the linker script language as an equivalent to the -u
 393   command-line option.
 394
 395 * Added ASSERT to the linker script language.
 396
 397 * Added EXCLUDE_FILE to the linker script language for further control over
 398   wildcard file names.
 399
 400 * Added -O option to optimize linker output (as of this writing, this only
 401   affects ELF shared library generation).
 402
 403 * The -e option now accepts a number as well as a symbol name.
 404
 405 * Added --no-undefined option to disallow undefined symbols when creating a
 406   shared library.
 407
 408 * The linker now issues a warning, not an error, for an undefined symbol when
 409   using -Bsymbolic; use the new --no-undefined option to get the old
 410   behaviour.
 411
 412 * Added --demangle and --no-demangle options.
 413
 414 Changes in version 2.9:
 415
 416 * Added SQUAD to the linker script language.
 417
 418 * New option --no-warn-mismatch.
 419
 420 * The MEMORY command now parses the attributes to determine where sections that
 421   are not placed in a specific memory region are placed.
 422
 423 Changes in version 2.8:
 424
 425 * Linker scripts may now contain shell wildcard characters for file and section
 426   names.
 427
 428 * The linker now supports symbol versions in ELF.
 429
 430 * The NOCROSSREFS command was added to the linker script language.
 431
 432 * The LOADADDR expression was added to the linker script language.
 433
 434 * MAX and MIN functions were added to the linker script language.
 435
 436 * The OVERLAY construct was added to the linker script language.
 437
 438 * New option --warn-section-align to warn when the address of an output section
 439   changes due to alignment of an input section.
 440
 441 * New options --filter/-F and --auxiliary/-f.
 442
 443 Changes in version 2.7:
 444
 445 * New option --cref to print out a cross reference table.
 446
 447 * New option --wrap SYMBOL.
 448
 449 * New option --no-whole-archive, to turn off the effect of --whole-archive.
 450
 451 * Input sections assigned to the output section /DISCARD/ in the linker script
 452   are not included in the output file.
 453
 454 * The SunOS and ELF linkers now merge stabs debugging information which uses
 455   the N_BINCL and N_EINCL stab types.  This reduces the amount of debugging
 456   information generated.
 457
 458 Changes in version 2.6:
 459
 460 * When an ELF section name is representable as a C identifier (this is not true
 461 of most ELF section names), the linker will automatically define symbols
 462 __start_SECNAME and __stop_SECNAME, where SECNAME is the section name, at the
 463 beginning and the end of the section.  This is used by glibc.
 464
 465   Addendum: Current versions of the linker (at least for version 2.18 onwards
 466 and possibly much earlier as well) place two restrictions on this feature:  The
 467 symbols are only implemented for orphaned sections, not for explicitly placed
 468 sections and they are PROVIDEd rather than being defined.
 469
 470 * When an ELF section named .gnu.warning is encountered in an input file, the
 471 contents of the section are displayed as an error message, and the section is
 472 not copied into the output file.  This is used by glibc.
 473
 474 * When an ELF section named .gnu.warning.SYMBOL is encountered in an input
 475 file, and the symbol SYMBOL is referenced by some object file, the contents of
 476 the section are displayed as an error message.  The section is not copied into
 477 the output file, unless doing a relocatable or shared link.  This is used by
 478 glibc.
 479
 480 * New options -split-by-reloc and -split-by-file.
 481
 482 * The linker now supports linking PIC compiled code on SPARC SunOS.  It can
 483 also create SPARC SunOS shared libraries, and, like the native SunOS linker,
 484 will do so whenever there is an undefined symbol in the link and neither the -e
 485 nor the -r option was used.
 486
 487 * The -rpath option may be used on SunOS to set the list of directories to be
 488 searched at run time.  This overrides the default of building the list from the
 489 -L options.
 490
 491 * The COFF linker now combines debugging information for structs, unions, and
 492 enums, so that even if the same type is defined in multiple input files it will
 493 only be defined once in the output file.  The --traditional-format switch will
 494 prevent this optimization.
 495
 496 Changes in version 2.5:
 497
 498 * The linker now supports linking against SunOS shared libraries.  It still can
 499 not link SunOS PIC (Position Independent Code) files, so it can not be used to
 500 generate shared libraries.
 501
 502 * The linker now supports linking against ELF shared libraries for the i386
 503 (UnixWare) and SPARC (Solaris).  It can also link ELF PIC files, and can be
 504 used to generate shared libraries.  Shared library generation is not well
 505 tested; please report any problems encountered.  The linker is now enabled for
 506 Solaris again.
 507
 508 * Eric Youngdale has contributed Linux support code, including linking against
 509 Linux a.out shared libraries.  The linker produces Linux QMAGIC binaries.
 510
 511 * The ELF backend has been converted to the new linker code.  To use the new
 512 ELF linker, each particular target requires a relocation function.  So far,
 513 this function has been written for i386 (UnixWare), SPARC (Solaris) MIPS (Irix
 514 5), and HPPA ELF targets.
 515
 516 * The -( (--start-group) and -) (--end-group) options have been added to
 517 support searching a group of archives as though they were a single archive.
 518 This can also be used in a linker script, as GROUP ( files ).
 519
 520 * When a file is named on the command line, and the linker does not recognize
 521 it as an object file, the linker will now treat the file as a linker script
 522 file.  A linker script named in this way augments, but does not replace, the
 523 default linker script.
 524
 525 * The -warn-once option was added.  It causes the linker to only warn once per
 526 undefined symbol, rather than once per reference.
 527
 528 * The COFF backend has been converted to the new linker code.  As with ELF, to
 529 use the new linker, each particular target requires a relocation function.  So
 530 far, this function has been written for the i386, m68k, a29k and SH targets.
 531
 532 * The -V flag was made a synonym for -v, for SVR4 compatibility.  The old -V
 533 behaviour is available via --verbose.
 534
 535 Changes in version 2.4:
 536
 537 * New linker code, by Steve Chamberlain and Ian Taylor.  For a.out and ecoff
 538   formats (so far), this should result in considerable savings in time
 539   and memory used while linking; slightly poorer performance than
 540   before for formats not converted yet.
 541
 542 * Command-line parsing is no longer done with flex.  This means
 543   oddball characters in filenames won't get treated as argument
 544   separators.
 545
 546 * HP-PA ELF support, by Jeff Law.  (No SOM support yet.)
 547
 548 * Mach i386 support, by David Mackenzie.
 549
 550 * Irix 4 shared libraries are now supported (Irix 5 uses ELF, and ELF shared
 551   libraries are not yet supported).
 552
 553 * COFF shared libraries (as on SCO) should work as well.
 554
 555 * The linker is disabled for Solaris.  (Actually, it was in 2.3 also, I just
 556   forgot to note it.)  Some of their C library routines don't work when
 557   statically linked, and the GNU linker doesn't support dynamic linking yet.
 558
 559 Changes in version 2.3:
 560
 561 * Weak symbols are now supported.
 562
 563 * ELF support has been added.  The linker has been bootstrapped on
 564   UnixWare and Solaris.
 565
 566 * Alpha OSF/1 support has been added (non dynamic linking only).
 567
 568 Changes in version 2.2:
 569
 570 * The `bfd' library has been updated to reduce a.out-format string
 571   table size.  The effect of this is that files linked from many input
 572   files with duplicate symbols (`-g' debugging records, or identical
 573   static symbols) should be much smaller.
 574
 575 Changes in version 2.1:
 576
 577 * The ld -ySYMBOL flag (to trace references to SYMBOL) is now implemented.
 578
 579 * There is now support for writing ECOFF files, so ld and the
 580   other utilities should work on Risc/Ultrix and Irix.
 581
 582 \f
 583 Copyright (C) 2012 Free Software Foundation, Inc.
 584
 585 Copying and distribution of this file, with or without modification,
 586 are permitted in any medium without royalty provided the copyright
 587 notice and this notice are preserved.
 588
 589 Local variables:
 590 fill-column: 79
 591 End: