ld/NEWS

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