ld/NEWS

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