ld/NEWS

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