ld/NEWS

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