ld/NEWS

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