ld/NEWS

   1 -*- text -*-
   2
   3 * Add a linker-provided symbol when producing ELF output, '__ehdr_start'
   4   to point to the ELF file header (and nearby program headers) in the
   5   program's memory image.
   6
   7 * Add support for S12X processor.
   8
   9 * Add support for the VLE extension to the PowerPC architecture.
  10
  11 * Add support for the Freescale XGATE architecture.
  12
  13 * Add option -f FILE on AIX (for response file).
  14
  15 * Add support for the Renesas RL78 architecture.
  16
  17 * Add support for the Adapteva EPIPHANY architecture.
  18
  19 Changes in 2.22:
  20
  21 * --copy-dt-needed-entries is no longer enabled by default.  Instead
  22   --no-copy-dt-needed-entries is the default.
  23
  24 * INPUT_SECTION_FLAGS has been added to the linker script language
  25   to allow selection of input sections by section header section flags.
  26
  27 * Add support for the Tilera TILEPro and TILE-Gx architectures.
  28
  29 * Added SORT_BY_INIT_PRIORITY to the linker script language to permit
  30   sorting sections by numerical value of the GCC init_priority attribute
  31   encoded in the section name.
  32
  33 Changes in 2.21:
  34
  35 * Linker script expression evaluation is somewhat more sane.  This may
  36   break scripts that depend on quirks of the old expression evaluation.
  37
  38 * Turn off underscoring for x86_64 PE+-COFF targets.  For old behavior the
  39   option --enable-leading-mingw64-underscores can be used on configure of
  40   bfd.
  41
  42 * Add support for the TMS320C6000 (TI C6X) processor family.
  43
  44 * --add-needed renamed to --copy-dt-needed-entries in order to avoid confusion
  45   with --as-needed option.
  46
  47 * Extend .def file syntax by '== <ID>' for imports and exports. This allows
  48   to alias the import/export table name written in PE image.
  49
  50 * Add --exclude-all-symbols option to PE based linkers.  This prevents all
  51   symbols from automatically being exported.
  52
  53 * Add support for the Renesas RX processor.
  54
  55 * Add support for alpha-vms target.
  56
  57 Changes in 2.20:
  58
  59 * GNU/Linux targets now support the STB_GNU_UNIQUE symbol binding.  This is a
  60   GNU extension to the standard set of ELF symbol bindings.  The binding will
  61   be passed on to the dynamic linker which will make sure that in the entire
  62   process there is just one symbol with the given name and type in use.
  63
  64 * PE targets now support a GNU extension to allow the alignment of common
  65   common symbols to be specified.  This support uses custom options in
  66   the .drectve section, which will be disregarded by the native tools.
  67
  68 * PE targets now add primitive support for ELF version scripts; symbols
  69   are not versioned, but the local and global symbol visibility directives
  70   are respected when filtering symbols in auto-export mode.
  71
  72 * New option --no-export-dynamic to undo the effect of the -E and
  73   --export-dynamic options.
  74
  75 * ELF: --warn-alternate-em option to warn if an object has alternate
  76   ELF machine code.
  77
  78 * New script function REGION_ALIAS to add alias names to memory regions.
  79
  80 * PE targets no longer make use of the long section names PE extension to
  81   the COFF format when generating executable images, by default.  The old
  82   (slightly non-conformant) behaviour can still be invoked by using the
  83   new '--enable-long-section-names' command-line option.  It is also enabled
  84   automatically in the presence of un-stripped debug information, as GDB
  85   needs to be able to find the debug info sections by their full names.
  86
  87 * For GNU/Linux systems the linker will now avoid processing any relocations
  88   made against symbols of the STT_GNU_IFUNC type and instead emit them into
  89   the resulting binary for processing by the loader.
  90
  91 * --as-needed now links in a dynamic library if it satisfies undefined
  92   symbols in regular objects, or in other dynamic libraries.  In the
  93   latter case the library is not linked if it is found in a DT_NEEDED
  94   entry of one of the libraries already linked.
  95
  96 * Add a new command line option, -Ttext-segment ADDR, for ELF targets
  97   to set the address of the first byte of the text segment.
  98
  99 * Add support for Sunplus score architecture.
 100
 101 * Add new option --use-nul-prefixed-import-tables to ld for PE targets to
 102   allow fallback to old import table generation with null element prefix.
 103
 104 * Windows PE systems now support a new --exclude-modules-for-implib option,
 105   allowing users to partition object files and archive members between a DLL
 106   and its associated import library as they are generated during linking.
 107
 108 * Add support for Lattice Mico32 (lm32) architecture.
 109
 110 * Add CR16 ELF --embedded-relocs (used to embedded relocations into binaries
 111   for Embedded-PIC code) option.
 112
 113 * Add to the PE/PE+ targets the support of two different kinds of
 114   pseudo-relocations.  They can be selected by the switches
 115   --enable-runtime-pseudo-reloc-v1 and --enable-runtime-pseudo-reloc-v2.
 116   For the switch --enable-runtime-pseudo-reloc it uses for 32-bit
 117   runtime pseudo relocation version one, for 64-bit the version two.
 118
 119 Changes in 2.19:
 120
 121 * Linker scripts support a new INSERT command that makes it easier to
 122   augment the default script.
 123
 124 * Linker script input section filespecs may now specify a file within an
 125   archive by writing "archive:file".
 126
 127 * The --sort-common switch now has an optional argument which specifies the
 128   direction of sorting.
 129
 130 * The M68K linker now supports multiple GOT generation schemes controlled via
 131   the --got=<type> command line option.
 132
 133 * The ARM EABI linker will now generate stubs for function calls to symbols
 134   that are too far away.  The placement of the stubs is controlled by a new
 135   linker command line option: --stub-group-size=N.
 136
 137 Changes in 2.18:
 138
 139 * Linker sources now released under version 3 of the GNU General Public
 140   License.
 141
 142 * ELF: New --build-id option to generate a unique per-binary identifier
 143   embedded in a note section.
 144
 145 * Added support for National Semicondutor CompactRISC (ie CR16) target.
 146
 147 * -l:foo now searches the library path for a filename called foo,
 148   without converting it to libfoo.a or libfoo.so.
 149
 150 * Add a new command line option '--default-script=FILE' or '-dT FILE'
 151   which specifies a replacement for the built in, default linker
 152   script.
 153
 154 * ELF: Add -Bsymbolic-functions, --dynamic-list-cpp-new, which puts C++
 155   operator new and delete on the dynamic list, and --dynamic-list-data,
 156   builtin list for --dynamic-list, which puts global data symbols on the
 157   dynamic list.
 158
 159 * Add support for x86_64 PE+ target.
 160
 161 * Add support for Score target.
 162
 163 * ELF: Add --dynamic-list option to specify a list of global symbols
 164   whose references shouldn't be bound to the definition within the
 165   shared library, or a list of symbols which should be added to the
 166   symbol table in the executable.
 167
 168 * The default output section LMA has changed for allocatable sections from
 169   being equal to VMA, to keeping the difference between LMA and VMA the same as
 170   the previous output section in the same region.  This is a more useful
 171   default when using overlays and other cases where you specify an LMA
 172   differing from the VMA for some sections.
 173
 174 * New switch: --print-gc-sections to list any sections removed by garabge
 175   collection.
 176
 177 * ARM: Added --vfp11-denorm-fix option to work around an erratum in current
 178   VFP11 coprocessors.
 179
 180 Changes in 2.17:
 181
 182 * Support for the Infineon XC16X has been added by KPIT Cummins Infosystems.
 183
 184 * Modify the Linux linker search order to better match ld.so search order.
 185   Look for DT_NEEDED libraries in paths specified by ld.so.conf before
 186   searching the default directories, rather than vice versa.
 187   Use $prefix/etc/ld.so.conf if it exists, otherwise /etc/ld.so.conf.
 188
 189 * PE-COFF: Forward exports from DLL's can now be specified in .def files
 190   passed directly to ld.
 191
 192 * Support for the Z80 processor family has been added.
 193
 194 * Add support for the "@<file>" syntax to the command line, so that extra
 195   switches can be read from <file>.
 196
 197 Changes in 2.16:
 198
 199 * Support for the R_ARM_V4BX relocation as defined in the ARM AAELF
 200   specification has been added via the --fix-v4bx command-line option.
 201
 202 * New linker script construct AS_NEEDED(), which sets the --as-needed flag
 203   for input files listed inside of it.
 204
 205 * A new command-line option, --sysroot, can be used to override the
 206   default sysroot location.  It only applies to toolchains that were
 207   configured using --with-sysroot.
 208
 209 * New linker script functions: ORIGIN() and LENGTH() which return information
 210   about a specified memory region.
 211
 212 * Port to MAXQ processor contributed by HCL Tech.
 213
 214 * Added SEGMENT_START to the linker script language to permit the user to
 215   override the base address for a segment from the command-line.
 216
 217 * ELF: --warn-shared-textrel option to warn if adding a DT_TEXTREL to a shared
 218   object.
 219
 220 * Added SORT_BY_NAME and SORT_BY_ALIGNMENT to the linker script
 221   language to permit sorting sections by section name or section
 222   maximum alignment.
 223
 224 * Added a new linker command line switch, --sort-section name|alignment,
 225   to sort sections by section name or maximum alignment.
 226
 227 * ELF: --add-needed/--no-add-needed options to control if a DT_NEEDED tag
 228   should be added when a shared library comes from DT_NEEDED tags.
 229
 230 * Support for the crx-elf target added.
 231
 232 * Support for the sh-symbianelf target added.
 233
 234 * A new linker command line switch has been added which allows the hash table
 235   size to be set to a suitable prime value near to its argument.  This switch
 236   is --hash-size=<NUMBER>.  Also if the switch --reduce-memory-overheads is
 237   used, and --hash-size has not been used, then the default value will be set
 238   to 1021.
 239
 240 * Linker map files are now generated with an O(N) algorithm for finding symbols
 241   that are defined in each section.  This uses about 40% more memory for
 242   symbols than the old O(N^2) algorithm.  You can use the new
 243   --reduce-memory-overheads option to select the old algorithm; this option
 244   might also be used in the future to select similar tradeoffs.
 245
 246 Changes in 2.15:
 247
 248 * ELF: --as-needed/--no-as-needed options to control if a DT_NEEDED tag should
 249   be added only when a shared library is referenced.
 250
 251 * PE: --large-address-aware option to indicate executables support virtual
 252   addresses greater than 2 gigabytes.
 253
 254 * DWARF 2 support for i386pe added.
 255
 256 * The linker script operator DEFINED() will now yield 1 only for a symbol that
 257   is defined before the statement where DEFINED is used.
 258
 259 * The MIPS --embedded-relocs (used to embed relocations into binaries for
 260   Embedded-PIC code) is deprecated and will be removed in a future release.
 261
 262 * cr16c support added by NSC.
 263
 264 * m32r Linux (ELF) support added by Renesas.
 265
 266 * Improved linker's handling of unresolved symbols.  The switch
 267   --unresolved-symbols=<method> has been added to tell the linker when it
 268   should report them and the switch --warn-unresolved-symbols has been added to
 269   make reports be issued as warning messages rather than errors.
 270
 271 Changes in 2.14:
 272
 273 * Added support for Xtensa architecture.
 274
 275 * Added --with-sysroot configure switch to specify a target system root, for
 276   linking against a target filesystem image.
 277
 278 * Added --accept-unknown-linker-format to restore old linker behaviour (pre
 279   2.14) of silently accepting and linking in any files in an unknown binary
 280   file format.
 281
 282 * Added --no-omagic to undo the effects of the -N option.
 283
 284 * Support for Texas Instruments TMS320C4x and TMS320C3x series of
 285   DSP's contributed by Michael Hayes and Svein E. Seldal.
 286
 287 * Added --with-lib-path configure switch to specify default value for
 288   LIB_PATH.
 289
 290 * ARM port to QNX operating system added by Graeme Peterson.
 291
 292 * IP2K support added by Denis Chertykov.
 293
 294 Changes in 2.13:
 295
 296 * Support for the Fujitsu FRV architecture added by Red Hat. Models for FR400
 297   and FR500 included.
 298
 299 Changes in version 2.13:
 300
 301 * DEC VAX ELF support, by Matt Thomas.
 302
 303 Changes in version 2.12:
 304
 305 * Support for Don Knuth's MMIX, by Hans-Peter Nilsson.
 306
 307 * Support for the OpenRISC 32-bit embedded processor by OpenCores.
 308
 309 * Support for -z nocopyreloc in the x86 ELF linker, which disables
 310   production of copy relocs.  Warning: using this option may result in
 311   non-sharable applications.
 312
 313 * Support for -z combreloc in the ELF linker, which puts dynamic
 314   relocations against the same symbol together, so that dynamic linker
 315   can use an one-entry symbol lookup cache.
 316
 317 * Support for ELF SHF_MERGE section merging, by Jakub Jelinek.
 318
 319 Changes in version 2.11:
 320
 321 * Support for AMD x86-64 architecture, by Jan Hubicka, SuSE Labs.
 322
 323 * Support added for eliminating duplicate DWARF2 debug information by
 324   having the compiler generate the information in sections called
 325   .gnu.linkonce.wi.XXXX where XXXX is a checksum for the contents.  The
 326   linker then merges these sections together into the normal .debug_info
 327   section.
 328
 329 * The native ELF linker now searches the directories in DT_RUNPATH or
 330   DT_RPATH of a shared library for shared libraries needed by it.
 331
 332 * TI C54x support, by Timothy Wall.
 333
 334 * Added command line switch --section-start to set the start address of any
 335   specified section.
 336
 337 * Added ability to emit full relocation information in linked executables,
 338   enabled by --emit-relocs.  Some post-linkage optimization tools need
 339   this information in order to be able to correctly identify and perform
 340   symbol relative addressing in the event of changes in section contents
 341   (instructions being added or deleted, extending data sections, etc.)
 342
 343 * Support for i860, by Jason Eckhardt (preliminary, alpha quality).
 344
 345 * Support for CRIS (Axis Communications ETRAX series).
 346
 347 * Support for PDP-11 and 2.11BSD a.out format, by Lars Brinkhoff.
 348
 349 Changes in version 2.10:
 350
 351 * Added AT> to the linker script language to allow load-time allocation of
 352   sections into regions.
 353
 354 * Added garbage collection of unused sections, enabled by --gc-sections.
 355   It does require a bit of backend support; currently implemented are
 356   arm-elf, avr-elf, d10v-elf, fr30-elf, i386-elf, m32r-elf, m68k-elf,
 357   mcore-elf, mips-elf, mn10300-elf, ppc-elf, sh-elf, sparc-elf, and v850-elf.
 358   Others will ignore the option.
 359
 360 * Added SORT to the linker script language to permit sorting sections by file
 361   name or section name.
 362
 363 * Added EXTERN to the linker script language as an equivalent to the -u
 364   command-line option.
 365
 366 * Added ASSERT to the linker script language.
 367
 368 * Added EXCLUDE_FILE to the linker script language for further control over
 369   wildcard file names.
 370
 371 * Added -O option to optimize linker output (as of this writing, this only
 372   affects ELF shared library generation).
 373
 374 * The -e option now accepts a number as well as a symbol name.
 375
 376 * Added --no-undefined option to disallow undefined symbols when creating a
 377   shared library.
 378
 379 * The linker now issues a warning, not an error, for an undefined symbol when
 380   using -Bsymbolic; use the new --no-undefined option to get the old
 381   behaviour.
 382
 383 * Added --demangle and --no-demangle options.
 384
 385 Changes in version 2.9:
 386
 387 * Added SQUAD to the linker script language.
 388
 389 * New option --no-warn-mismatch.
 390
 391 * The MEMORY command now parses the attributes to determine where sections that
 392   are not placed in a specific memory region are placed.
 393
 394 Changes in version 2.8:
 395
 396 * Linker scripts may now contain shell wildcard characters for file and section
 397   names.
 398
 399 * The linker now supports symbol versions in ELF.
 400
 401 * The NOCROSSREFS command was added to the linker script language.
 402
 403 * The LOADADDR expression was added to the linker script language.
 404
 405 * MAX and MIN functions were added to the linker script language.
 406
 407 * The OVERLAY construct was added to the linker script language.
 408
 409 * New option --warn-section-align to warn when the address of an output section
 410   changes due to alignment of an input section.
 411
 412 * New options --filter/-F and --auxiliary/-f.
 413
 414 Changes in version 2.7:
 415
 416 * New option --cref to print out a cross reference table.
 417
 418 * New option --wrap SYMBOL.
 419
 420 * New option --no-whole-archive, to turn off the effect of --whole-archive.
 421
 422 * Input sections assigned to the output section /DISCARD/ in the linker script
 423   are not included in the output file.
 424
 425 * The SunOS and ELF linkers now merge stabs debugging information which uses
 426   the N_BINCL and N_EINCL stab types.  This reduces the amount of debugging
 427   information generated.
 428
 429 Changes in version 2.6:
 430
 431 * When an ELF section name is representable as a C identifier (this is not true
 432 of most ELF section names), the linker will automatically define symbols
 433 __start_SECNAME and __stop_SECNAME, where SECNAME is the section name, at the
 434 beginning and the end of the section.  This is used by glibc.
 435
 436   Addendum: Current versions of the linker (at least for version 2.18 onwards
 437 and possibly much earlier as well) place two restrictions on this feature:  The
 438 symbols are only implemented for orphaned sections, not for explicitly placed
 439 sections and they are PROVIDEd rather than being defined.
 440
 441 * When an ELF section named .gnu.warning is encountered in an input file, the
 442 contents of the section are displayed as an error message, and the section is
 443 not copied into the output file.  This is used by glibc.
 444
 445 * When an ELF section named .gnu.warning.SYMBOL is encountered in an input
 446 file, and the symbol SYMBOL is referenced by some object file, the contents of
 447 the section are displayed as an error message.  The section is not copied into
 448 the output file, unless doing a relocatable or shared link.  This is used by
 449 glibc.
 450
 451 * New options -split-by-reloc and -split-by-file.
 452
 453 * The linker now supports linking PIC compiled code on SPARC SunOS.  It can
 454 also create SPARC SunOS shared libraries, and, like the native SunOS linker,
 455 will do so whenever there is an undefined symbol in the link and neither the -e
 456 nor the -r option was used.
 457
 458 * The -rpath option may be used on SunOS to set the list of directories to be
 459 searched at run time.  This overrides the default of building the list from the
 460 -L options.
 461
 462 * The COFF linker now combines debugging information for structs, unions, and
 463 enums, so that even if the same type is defined in multiple input files it will
 464 only be defined once in the output file.  The --traditional-format switch will
 465 prevent this optimization.
 466
 467 Changes in version 2.5:
 468
 469 * The linker now supports linking against SunOS shared libraries.  It still can
 470 not link SunOS PIC (Position Independent Code) files, so it can not be used to
 471 generate shared libraries.
 472
 473 * The linker now supports linking against ELF shared libraries for the i386
 474 (UnixWare) and SPARC (Solaris).  It can also link ELF PIC files, and can be
 475 used to generate shared libraries.  Shared library generation is not well
 476 tested; please report any problems encountered.  The linker is now enabled for
 477 Solaris again.
 478
 479 * Eric Youngdale has contributed Linux support code, including linking against
 480 Linux a.out shared libraries.  The linker produces Linux QMAGIC binaries.
 481
 482 * The ELF backend has been converted to the new linker code.  To use the new
 483 ELF linker, each particular target requires a relocation function.  So far,
 484 this function has been written for i386 (UnixWare), SPARC (Solaris) MIPS (Irix
 485 5), and HPPA ELF targets.
 486
 487 * The -( (--start-group) and -) (--end-group) options have been added to
 488 support searching a group of archives as though they were a single archive.
 489 This can also be used in a linker script, as GROUP ( files ).
 490
 491 * When a file is named on the command line, and the linker does not recognize
 492 it as an object file, the linker will now treat the file as a linker script
 493 file.  A linker script named in this way augments, but does not replace, the
 494 default linker script.
 495
 496 * The -warn-once option was added.  It causes the linker to only warn once per
 497 undefined symbol, rather than once per reference.
 498
 499 * The COFF backend has been converted to the new linker code.  As with ELF, to
 500 use the new linker, each particular target requires a relocation function.  So
 501 far, this function has been written for the i386, m68k, a29k and SH targets.
 502
 503 * The -V flag was made a synonym for -v, for SVR4 compatibility.  The old -V
 504 behaviour is available via --verbose.
 505
 506 Changes in version 2.4:
 507
 508 * New linker code, by Steve Chamberlain and Ian Taylor.  For a.out and ecoff
 509   formats (so far), this should result in considerable savings in time
 510   and memory used while linking; slightly poorer performance than
 511   before for formats not converted yet.
 512
 513 * Command-line parsing is no longer done with flex.  This means
 514   oddball characters in filenames won't get treated as argument
 515   separators.
 516
 517 * HP-PA ELF support, by Jeff Law.  (No SOM support yet.)
 518
 519 * Mach i386 support, by David Mackenzie.
 520
 521 * Irix 4 shared libraries are now supported (Irix 5 uses ELF, and ELF shared
 522   libraries are not yet supported).
 523
 524 * COFF shared libraries (as on SCO) should work as well.
 525
 526 * The linker is disabled for Solaris.  (Actually, it was in 2.3 also, I just
 527   forgot to note it.)  Some of their C library routines don't work when
 528   statically linked, and the GNU linker doesn't support dynamic linking yet.
 529
 530 Changes in version 2.3:
 531
 532 * Weak symbols are now supported.
 533
 534 * ELF support has been added.  The linker has been bootstrapped on
 535   UnixWare and Solaris.
 536
 537 * Alpha OSF/1 support has been added (non dynamic linking only).
 538
 539 Changes in version 2.2:
 540
 541 * The `bfd' library has been updated to reduce a.out-format string
 542   table size.  The effect of this is that files linked from many input
 543   files with duplicate symbols (`-g' debugging records, or identical
 544   static symbols) should be much smaller.
 545
 546 Changes in version 2.1:
 547
 548 * The ld -ySYMBOL flag (to trace references to SYMBOL) is now implemented.
 549
 550 * There is now support for writing ECOFF files, so ld and the
 551   other utilities should work on Risc/Ultrix and Irix.
 552
 553 \f
 554 Local variables:
 555 fill-column: 79
 556 End: