ld/NEWS

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