ld/NEWS

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