ld/NEWS

   1 -*- text -*-
   2
   3 * New command line option for ELF targets to compress DWARF debug
   4   sections, --compress-debug-sections=[none|zlib|zlib-gnu|zlib-gabi].
   5
   6 * Add --warn-orphan option to report orphan sections.
   7
   8 * Add support for LLVM plugin.
   9
  10 Changes in 2.25:
  11
  12 * PE binaries now once again contain real timestamps by default.  To disable
  13   the inclusion of a timestamp in a PE binary, use the --no-insert-timestamp
  14   command line option.
  15
  16 * Replace support for openrisc and or32 with support for or1k.
  17
  18 * Add support for the --build-id command line option to COFF based targets.
  19
  20 * x86/x86_64 pe-coff now supports the --build-id option.
  21
  22 * Add support for the Andes NDS32.
  23
  24 Changes in 2.24:
  25
  26 * Add LOG2CEIL() builtin function to the linker script language
  27
  28 * Add support for the Texas Instruments MSP430X processor.
  29
  30 * Add support for Altera Nios II.
  31
  32 * Add support for the V850E3V5 architecture.
  33
  34 * Add support for the Imagination Technologies Meta processor.
  35
  36 * --enable-new-dtags no longer generates old dtags in addition to new dtags.
  37
  38 * Remove linker support for MIPS ECOFF targets.
  39
  40 * Add ALIGN_WITH_INPUT to the linker script language to force the alignment of
  41   an output section to use the maximum alignment of all its input sections.
  42
  43 Changes in 2.23:
  44
  45 * Enable compressed debug section feature for x86/x86_64 pe-coff.
  46
  47 * Add support for the 64-bit ARM architecture: AArch64.
  48
  49 * Added SORT_NONE to the linker script language to disable section sorting.
  50
  51 * Add a linker-provided symbol when producing ELF output, '__ehdr_start'
  52   to point to the ELF file header (and nearby program headers) in the
  53   program's memory image.
  54
  55 * Add support for S12X processor.
  56
  57 * Add support for the VLE extension to the PowerPC architecture.
  58
  59 * Add support for the Freescale XGATE architecture.
  60
  61 * Add option -f FILE on AIX (for response file).
  62
  63 * Add support for the Renesas RL78 architecture.
  64
  65 * Add support for the Adapteva EPIPHANY architecture.
  66
  67 Changes in 2.22:
  68
  69 * --copy-dt-needed-entries is no longer enabled by default.  Instead
  70   --no-copy-dt-needed-entries is the default.
  71
  72 * INPUT_SECTION_FLAGS has been added to the linker script language
  73   to allow selection of input sections by section header section flags.
  74
  75 * Add support for the Tilera TILEPro and TILE-Gx architectures.
  76
  77 * Added SORT_BY_INIT_PRIORITY to the linker script language to permit
  78   sorting sections by numerical value of the GCC init_priority attribute
  79   encoded in the section name.
  80
  81 Changes in 2.21:
  82
  83 * Linker script expression evaluation is somewhat more sane.  This may
  84   break scripts that depend on quirks of the old expression evaluation.
  85
  86 * Turn off underscoring for x86_64 PE+-COFF targets.  For old behavior the
  87   option --enable-leading-mingw64-underscores can be used on configure of
  88   bfd.
  89
  90 * Add support for the TMS320C6000 (TI C6X) processor family.
  91
  92 * --add-needed renamed to --copy-dt-needed-entries in order to avoid confusion
  93   with --as-needed option.
  94
  95 * Extend .def file syntax by '== <ID>' for imports and exports. This allows
  96   to alias the import/export table name written in PE image.
  97
  98 * Add --exclude-all-symbols option to PE based linkers.  This prevents all
  99   symbols from automatically being exported.
 100
 101 * Add support for the Renesas RX processor.
 102
 103 * Add support for alpha-vms target.
 104
 105 Changes in 2.20:
 106
 107 * GNU/Linux targets now support the STB_GNU_UNIQUE symbol binding.  This is a
 108   GNU extension to the standard set of ELF symbol bindings.  The binding will
 109   be passed on to the dynamic linker which will make sure that in the entire
 110   process there is just one symbol with the given name and type in use.
 111
 112 * PE targets now support a GNU extension to allow the alignment of common
 113   common symbols to be specified.  This support uses custom options in
 114   the .drectve section, which will be disregarded by the native tools.
 115
 116 * PE targets now add primitive support for ELF version scripts; symbols
 117   are not versioned, but the local and global symbol visibility directives
 118   are respected when filtering symbols in auto-export mode.
 119
 120 * New option --no-export-dynamic to undo the effect of the -E and
 121   --export-dynamic options.
 122
 123 * ELF: --warn-alternate-em option to warn if an object has alternate
 124   ELF machine code.
 125
 126 * New script function REGION_ALIAS to add alias names to memory regions.
 127
 128 * PE targets no longer make use of the long section names PE extension to
 129   the COFF format when generating executable images, by default.  The old
 130   (slightly non-conformant) behaviour can still be invoked by using the
 131   new '--enable-long-section-names' command-line option.  It is also enabled
 132   automatically in the presence of un-stripped debug information, as GDB
 133   needs to be able to find the debug info sections by their full names.
 134
 135 * For GNU/Linux systems the linker will now avoid processing any relocations
 136   made against symbols of the STT_GNU_IFUNC type and instead emit them into
 137   the resulting binary for processing by the loader.
 138
 139 * --as-needed now links in a dynamic library if it satisfies undefined
 140   symbols in regular objects, or in other dynamic libraries.  In the
 141   latter case the library is not linked if it is found in a DT_NEEDED
 142   entry of one of the libraries already linked.
 143
 144 * Add a new command line option, -Ttext-segment ADDR, for ELF targets
 145   to set the address of the first byte of the text segment.
 146
 147 * Add support for Sunplus score architecture.
 148
 149 * Add new option --use-nul-prefixed-import-tables to ld for PE targets to
 150   allow fallback to old import table generation with null element prefix.
 151
 152 * Windows PE systems now support a new --exclude-modules-for-implib option,
 153   allowing users to partition object files and archive members between a DLL
 154   and its associated import library as they are generated during linking.
 155
 156 * Add support for Lattice Mico32 (lm32) architecture.
 157
 158 * Add CR16 ELF --embedded-relocs (used to embedded relocations into binaries
 159   for Embedded-PIC code) option.
 160
 161 * Add to the PE/PE+ targets the support of two different kinds of
 162   pseudo-relocations.  They can be selected by the switches
 163   --enable-runtime-pseudo-reloc-v1 and --enable-runtime-pseudo-reloc-v2.
 164   For the switch --enable-runtime-pseudo-reloc it uses for 32-bit
 165   runtime pseudo relocation version one, for 64-bit the version two.
 166
 167 Changes in 2.19:
 168
 169 * Linker scripts support a new INSERT command that makes it easier to
 170   augment the default script.
 171
 172 * Linker script input section filespecs may now specify a file within an
 173   archive by writing "archive:file".
 174
 175 * The --sort-common switch now has an optional argument which specifies the
 176   direction of sorting.
 177
 178 * The M68K linker now supports multiple GOT generation schemes controlled via
 179   the --got=<type> command line option.
 180
 181 * The ARM EABI linker will now generate stubs for function calls to symbols
 182   that are too far away.  The placement of the stubs is controlled by a new
 183   linker command line option: --stub-group-size=N.
 184
 185 Changes in 2.18:
 186
 187 * Linker sources now released under version 3 of the GNU General Public
 188   License.
 189
 190 * ELF: New --build-id option to generate a unique per-binary identifier
 191   embedded in a note section.
 192
 193 * Added support for National Semicondutor CompactRISC (ie CR16) target.
 194
 195 * -l:foo now searches the library path for a filename called foo,
 196   without converting it to libfoo.a or libfoo.so.
 197
 198 * Add a new command line option '--default-script=FILE' or '-dT FILE'
 199   which specifies a replacement for the built in, default linker
 200   script.
 201
 202 * ELF: Add -Bsymbolic-functions, --dynamic-list-cpp-new, which puts C++
 203   operator new and delete on the dynamic list, and --dynamic-list-data,
 204   builtin list for --dynamic-list, which puts global data symbols on the
 205   dynamic list.
 206
 207 * Add support for x86_64 PE+ target.
 208
 209 * Add support for Score target.
 210
 211 * ELF: Add --dynamic-list option to specify a list of global symbols
 212   whose references shouldn't be bound to the definition within the
 213   shared library, or a list of symbols which should be added to the
 214   symbol table in the executable.
 215
 216 * The default output section LMA has changed for allocatable sections from
 217   being equal to VMA, to keeping the difference between LMA and VMA the same as
 218   the previous output section in the same region.  This is a more useful
 219   default when using overlays and other cases where you specify an LMA
 220   differing from the VMA for some sections.
 221
 222 * New switch: --print-gc-sections to list any sections removed by garabge
 223   collection.
 224
 225 * ARM: Added --vfp11-denorm-fix option to work around an erratum in current
 226   VFP11 coprocessors.
 227
 228 Changes in 2.17:
 229
 230 * Support for the Infineon XC16X has been added by KPIT Cummins Infosystems.
 231
 232 * Modify the Linux linker search order to better match ld.so search order.
 233   Look for DT_NEEDED libraries in paths specified by ld.so.conf before
 234   searching the default directories, rather than vice versa.
 235   Use $prefix/etc/ld.so.conf if it exists, otherwise /etc/ld.so.conf.
 236
 237 * PE-COFF: Forward exports from DLL's can now be specified in .def files
 238   passed directly to ld.
 239
 240 * Support for the Z80 processor family has been added.
 241
 242 * Add support for the "@<file>" syntax to the command line, so that extra
 243   switches can be read from <file>.
 244
 245 Changes in 2.16:
 246
 247 * Support for the R_ARM_V4BX relocation as defined in the ARM AAELF
 248   specification has been added via the --fix-v4bx command-line option.
 249
 250 * New linker script construct AS_NEEDED(), which sets the --as-needed flag
 251   for input files listed inside of it.
 252
 253 * A new command-line option, --sysroot, can be used to override the
 254   default sysroot location.  It only applies to toolchains that were
 255   configured using --with-sysroot.
 256
 257 * New linker script functions: ORIGIN() and LENGTH() which return information
 258   about a specified memory region.
 259
 260 * Port to MAXQ processor contributed by HCL Tech.
 261
 262 * Added SEGMENT_START to the linker script language to permit the user to
 263   override the base address for a segment from the command-line.
 264
 265 * ELF: --warn-shared-textrel option to warn if adding a DT_TEXTREL to a shared
 266   object.
 267
 268 * Added SORT_BY_NAME and SORT_BY_ALIGNMENT to the linker script
 269   language to permit sorting sections by section name or section
 270   maximum alignment.
 271
 272 * Added a new linker command line switch, --sort-section name|alignment,
 273   to sort sections by section name or maximum alignment.
 274
 275 * ELF: --add-needed/--no-add-needed options to control if a DT_NEEDED tag
 276   should be added when a shared library comes from DT_NEEDED tags.
 277
 278 * Support for the crx-elf target added.
 279
 280 * Support for the sh-symbianelf target added.
 281
 282 * A new linker command line switch has been added which allows the hash table
 283   size to be set to a suitable prime value near to its argument.  This switch
 284   is --hash-size=<NUMBER>.  Also if the switch --reduce-memory-overheads is
 285   used, and --hash-size has not been used, then the default value will be set
 286   to 1021.
 287
 288 * Linker map files are now generated with an O(N) algorithm for finding symbols
 289   that are defined in each section.  This uses about 40% more memory for
 290   symbols than the old O(N^2) algorithm.  You can use the new
 291   --reduce-memory-overheads option to select the old algorithm; this option
 292   might also be used in the future to select similar tradeoffs.
 293
 294 Changes in 2.15:
 295
 296 * ELF: --as-needed/--no-as-needed options to control if a DT_NEEDED tag should
 297   be added only when a shared library is referenced.
 298
 299 * PE: --large-address-aware option to indicate executables support virtual
 300   addresses greater than 2 gigabytes.
 301
 302 * DWARF 2 support for i386pe added.
 303
 304 * The linker script operator DEFINED() will now yield 1 only for a symbol that
 305   is defined before the statement where DEFINED is used.
 306
 307 * The MIPS --embedded-relocs (used to embed relocations into binaries for
 308   Embedded-PIC code) is deprecated and will be removed in a future release.
 309
 310 * cr16c support added by NSC.
 311
 312 * m32r Linux (ELF) support added by Renesas.
 313
 314 * Improved linker's handling of unresolved symbols.  The switch
 315   --unresolved-symbols=<method> has been added to tell the linker when it
 316   should report them and the switch --warn-unresolved-symbols has been added to
 317   make reports be issued as warning messages rather than errors.
 318
 319 Changes in 2.14:
 320
 321 * Added support for Xtensa architecture.
 322
 323 * Added --with-sysroot configure switch to specify a target system root, for
 324   linking against a target filesystem image.
 325
 326 * Added --accept-unknown-linker-format to restore old linker behaviour (pre
 327   2.14) of silently accepting and linking in any files in an unknown binary
 328   file format.
 329
 330 * Added --no-omagic to undo the effects of the -N option.
 331
 332 * Support for Texas Instruments TMS320C4x and TMS320C3x series of
 333   DSP's contributed by Michael Hayes and Svein E. Seldal.
 334
 335 * Added --with-lib-path configure switch to specify default value for
 336   LIB_PATH.
 337
 338 * ARM port to QNX operating system added by Graeme Peterson.
 339
 340 * IP2K support added by Denis Chertykov.
 341
 342 Changes in 2.13:
 343
 344 * Support for the Fujitsu FRV architecture added by Red Hat. Models for FR400
 345   and FR500 included.
 346
 347 Changes in version 2.13:
 348
 349 * DEC VAX ELF support, by Matt Thomas.
 350
 351 Changes in version 2.12:
 352
 353 * Support for Don Knuth's MMIX, by Hans-Peter Nilsson.
 354
 355 * Support for the OpenRISC 32-bit embedded processor by OpenCores.
 356
 357 * Support for -z nocopyreloc in the x86 ELF linker, which disables
 358   production of copy relocs.  Warning: using this option may result in
 359   non-sharable applications.
 360
 361 * Support for -z combreloc in the ELF linker, which puts dynamic
 362   relocations against the same symbol together, so that dynamic linker
 363   can use an one-entry symbol lookup cache.
 364
 365 * Support for ELF SHF_MERGE section merging, by Jakub Jelinek.
 366
 367 Changes in version 2.11:
 368
 369 * Support for AMD x86-64 architecture, by Jan Hubicka, SuSE Labs.
 370
 371 * Support added for eliminating duplicate DWARF2 debug information by
 372   having the compiler generate the information in sections called
 373   .gnu.linkonce.wi.XXXX where XXXX is a checksum for the contents.  The
 374   linker then merges these sections together into the normal .debug_info
 375   section.
 376
 377 * The native ELF linker now searches the directories in DT_RUNPATH or
 378   DT_RPATH of a shared library for shared libraries needed by it.
 379
 380 * TI C54x support, by Timothy Wall.
 381
 382 * Added command line switch --section-start to set the start address of any
 383   specified section.
 384
 385 * Added ability to emit full relocation information in linked executables,
 386   enabled by --emit-relocs.  Some post-linkage optimization tools need
 387   this information in order to be able to correctly identify and perform
 388   symbol relative addressing in the event of changes in section contents
 389   (instructions being added or deleted, extending data sections, etc.)
 390
 391 * Support for i860, by Jason Eckhardt (preliminary, alpha quality).
 392
 393 * Support for CRIS (Axis Communications ETRAX series).
 394
 395 * Support for PDP-11 and 2.11BSD a.out format, by Lars Brinkhoff.
 396
 397 Changes in version 2.10:
 398
 399 * Added AT> to the linker script language to allow load-time allocation of
 400   sections into regions.
 401
 402 * Added garbage collection of unused sections, enabled by --gc-sections.
 403   It does require a bit of backend support; currently implemented are
 404   arm-elf, avr-elf, d10v-elf, fr30-elf, i386-elf, m32r-elf, m68k-elf,
 405   mcore-elf, mips-elf, mn10300-elf, ppc-elf, sh-elf, sparc-elf, and v850-elf.
 406   Others will ignore the option.
 407
 408 * Added SORT to the linker script language to permit sorting sections by file
 409   name or section name.
 410
 411 * Added EXTERN to the linker script language as an equivalent to the -u
 412   command-line option.
 413
 414 * Added ASSERT to the linker script language.
 415
 416 * Added EXCLUDE_FILE to the linker script language for further control over
 417   wildcard file names.
 418
 419 * Added -O option to optimize linker output (as of this writing, this only
 420   affects ELF shared library generation).
 421
 422 * The -e option now accepts a number as well as a symbol name.
 423
 424 * Added --no-undefined option to disallow undefined symbols when creating a
 425   shared library.
 426
 427 * The linker now issues a warning, not an error, for an undefined symbol when
 428   using -Bsymbolic; use the new --no-undefined option to get the old
 429   behaviour.
 430
 431 * Added --demangle and --no-demangle options.
 432
 433 Changes in version 2.9:
 434
 435 * Added SQUAD to the linker script language.
 436
 437 * New option --no-warn-mismatch.
 438
 439 * The MEMORY command now parses the attributes to determine where sections that
 440   are not placed in a specific memory region are placed.
 441
 442 Changes in version 2.8:
 443
 444 * Linker scripts may now contain shell wildcard characters for file and section
 445   names.
 446
 447 * The linker now supports symbol versions in ELF.
 448
 449 * The NOCROSSREFS command was added to the linker script language.
 450
 451 * The LOADADDR expression was added to the linker script language.
 452
 453 * MAX and MIN functions were added to the linker script language.
 454
 455 * The OVERLAY construct was added to the linker script language.
 456
 457 * New option --warn-section-align to warn when the address of an output section
 458   changes due to alignment of an input section.
 459
 460 * New options --filter/-F and --auxiliary/-f.
 461
 462 Changes in version 2.7:
 463
 464 * New option --cref to print out a cross reference table.
 465
 466 * New option --wrap SYMBOL.
 467
 468 * New option --no-whole-archive, to turn off the effect of --whole-archive.
 469
 470 * Input sections assigned to the output section /DISCARD/ in the linker script
 471   are not included in the output file.
 472
 473 * The SunOS and ELF linkers now merge stabs debugging information which uses
 474   the N_BINCL and N_EINCL stab types.  This reduces the amount of debugging
 475   information generated.
 476
 477 Changes in version 2.6:
 478
 479 * When an ELF section name is representable as a C identifier (this is not true
 480 of most ELF section names), the linker will automatically define symbols
 481 __start_SECNAME and __stop_SECNAME, where SECNAME is the section name, at the
 482 beginning and the end of the section.  This is used by glibc.
 483
 484   Addendum: Current versions of the linker (at least for version 2.18 onwards
 485 and possibly much earlier as well) place two restrictions on this feature:  The
 486 symbols are only implemented for orphaned sections, not for explicitly placed
 487 sections and they are PROVIDEd rather than being defined.
 488
 489 * When an ELF section named .gnu.warning is encountered in an input file, the
 490 contents of the section are displayed as an error message, and the section is
 491 not copied into the output file.  This is used by glibc.
 492
 493 * When an ELF section named .gnu.warning.SYMBOL is encountered in an input
 494 file, and the symbol SYMBOL is referenced by some object file, the contents of
 495 the section are displayed as an error message.  The section is not copied into
 496 the output file, unless doing a relocatable or shared link.  This is used by
 497 glibc.
 498
 499 * New options -split-by-reloc and -split-by-file.
 500
 501 * The linker now supports linking PIC compiled code on SPARC SunOS.  It can
 502 also create SPARC SunOS shared libraries, and, like the native SunOS linker,
 503 will do so whenever there is an undefined symbol in the link and neither the -e
 504 nor the -r option was used.
 505
 506 * The -rpath option may be used on SunOS to set the list of directories to be
 507 searched at run time.  This overrides the default of building the list from the
 508 -L options.
 509
 510 * The COFF linker now combines debugging information for structs, unions, and
 511 enums, so that even if the same type is defined in multiple input files it will
 512 only be defined once in the output file.  The --traditional-format switch will
 513 prevent this optimization.
 514
 515 Changes in version 2.5:
 516
 517 * The linker now supports linking against SunOS shared libraries.  It still can
 518 not link SunOS PIC (Position Independent Code) files, so it can not be used to
 519 generate shared libraries.
 520
 521 * The linker now supports linking against ELF shared libraries for the i386
 522 (UnixWare) and SPARC (Solaris).  It can also link ELF PIC files, and can be
 523 used to generate shared libraries.  Shared library generation is not well
 524 tested; please report any problems encountered.  The linker is now enabled for
 525 Solaris again.
 526
 527 * Eric Youngdale has contributed Linux support code, including linking against
 528 Linux a.out shared libraries.  The linker produces Linux QMAGIC binaries.
 529
 530 * The ELF backend has been converted to the new linker code.  To use the new
 531 ELF linker, each particular target requires a relocation function.  So far,
 532 this function has been written for i386 (UnixWare), SPARC (Solaris) MIPS (Irix
 533 5), and HPPA ELF targets.
 534
 535 * The -( (--start-group) and -) (--end-group) options have been added to
 536 support searching a group of archives as though they were a single archive.
 537 This can also be used in a linker script, as GROUP ( files ).
 538
 539 * When a file is named on the command line, and the linker does not recognize
 540 it as an object file, the linker will now treat the file as a linker script
 541 file.  A linker script named in this way augments, but does not replace, the
 542 default linker script.
 543
 544 * The -warn-once option was added.  It causes the linker to only warn once per
 545 undefined symbol, rather than once per reference.
 546
 547 * The COFF backend has been converted to the new linker code.  As with ELF, to
 548 use the new linker, each particular target requires a relocation function.  So
 549 far, this function has been written for the i386, m68k, a29k and SH targets.
 550
 551 * The -V flag was made a synonym for -v, for SVR4 compatibility.  The old -V
 552 behaviour is available via --verbose.
 553
 554 Changes in version 2.4:
 555
 556 * New linker code, by Steve Chamberlain and Ian Taylor.  For a.out and ecoff
 557   formats (so far), this should result in considerable savings in time
 558   and memory used while linking; slightly poorer performance than
 559   before for formats not converted yet.
 560
 561 * Command-line parsing is no longer done with flex.  This means
 562   oddball characters in filenames won't get treated as argument
 563   separators.
 564
 565 * HP-PA ELF support, by Jeff Law.  (No SOM support yet.)
 566
 567 * Mach i386 support, by David Mackenzie.
 568
 569 * Irix 4 shared libraries are now supported (Irix 5 uses ELF, and ELF shared
 570   libraries are not yet supported).
 571
 572 * COFF shared libraries (as on SCO) should work as well.
 573
 574 * The linker is disabled for Solaris.  (Actually, it was in 2.3 also, I just
 575   forgot to note it.)  Some of their C library routines don't work when
 576   statically linked, and the GNU linker doesn't support dynamic linking yet.
 577
 578 Changes in version 2.3:
 579
 580 * Weak symbols are now supported.
 581
 582 * ELF support has been added.  The linker has been bootstrapped on
 583   UnixWare and Solaris.
 584
 585 * Alpha OSF/1 support has been added (non dynamic linking only).
 586
 587 Changes in version 2.2:
 588
 589 * The `bfd' library has been updated to reduce a.out-format string
 590   table size.  The effect of this is that files linked from many input
 591   files with duplicate symbols (`-g' debugging records, or identical
 592   static symbols) should be much smaller.
 593
 594 Changes in version 2.1:
 595
 596 * The ld -ySYMBOL flag (to trace references to SYMBOL) is now implemented.
 597
 598 * There is now support for writing ECOFF files, so ld and the
 599   other utilities should work on Risc/Ultrix and Irix.
 600
 601 \f
 602 Copyright (C) 2012-2015 Free Software Foundation, Inc.
 603
 604 Copying and distribution of this file, with or without modification,
 605 are permitted in any medium without royalty provided the copyright
 606 notice and this notice are preserved.
 607
 608 Local variables:
 609 fill-column: 79
 610 End: