ld/NEWS

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