ld/NEWS

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