ld/NEWS

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