ld/NEWS

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