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