ld/NEWS

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