ld/NEWS

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