ld/NEWS

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