ld/NEWS

   1 -*- text -*-
   2
   3 * --as-needed now links in a dynamic library if it satisfies undefined
   4   symbols in regular objects, or in other dynamic libraries.  In the
   5   latter case the library is not linked if it is found in a DT_NEEDED
   6   entry of one of the libraries already linked.
   7
   8 * Add a new command line option, -Ttext-segment ADDR, for ELF targets
   9   to set the address of the first byte of the text segment.
  10
  11 * Add new option --use-nul-prefixed-import-tables to ld for PE targets to
  12   allow fallback to old import table generation with null element prefix.
  13
  14 * Windows PE systems now support a new --exclude-modules-for-implib option,
  15   allowing users to partition object files and archive members between a DLL
  16   and its associated import library as they are generated during linking.
  17
  18 * Add support for Lattice Mico32 (lm32) architecture.
  19
  20 * Add CR16 ELF --embedded-relocs (used to embedded relocations into binaries
  21   for Embedded-PIC code) option.
  22
  23 * Add to the PE/PE+ targets the support of two different kinds of
  24   pseudo-relocations.  They can be selected by the switches
  25   --enable-runtime-pseudo-reloc-v1 and --enable-runtime-pseudo-reloc-v2.
  26   For the switch --enable-runtime-pseudo-reloc it uses for 32-bit
  27   runtime pseudo relocation version one, for 64-bit the version two.
  28
  29 Changes in 2.19:
  30
  31 * Linker scripts support a new INSERT command that makes it easier to
  32   augment the default script.
  33
  34 * Linker script input section filespecs may now specify a file within an
  35   archive by writing "archive:file".
  36
  37 * The --sort-common switch now has an optional argument which specifies the
  38   direction of sorting.
  39
  40 * The M68K linker now supports multiple GOT generation schemes controlled via
  41   the --got=<type> command line option.
  42
  43 * The ARM EABI linker will now generate stubs for function calls to symbols
  44   that are too far away.  The placement of the stubs is controlled by a new
  45   linker command line option: --stub-group-size=N.
  46
  47 Changes in 2.18:
  48
  49 * Linker sources now released under version 3 of the GNU General Public
  50   License.
  51
  52 * ELF: New --build-id option to generate a unique per-binary identifier
  53   embedded in a note section.
  54
  55 * Added support for National Semicondutor CompactRISC (ie CR16) target.
  56
  57 * -l:foo now searches the library path for a filename called foo,
  58   without converting it to libfoo.a or libfoo.so.
  59
  60 * Add a new command line option '--default-script=FILE' or '-dT FILE'
  61   which specifies a replacement for the built in, default linker
  62   script.
  63
  64 * ELF: Add -Bsymbolic-functions, --dynamic-list-cpp-new, which puts C++
  65   operator new and delete on the dynamic list, and --dynamic-list-data,
  66   builtin list for --dynamic-list, which puts global data symbols on the
  67   dynamic list.
  68
  69 * Add support for x86_64 PE+ target.
  70
  71 * Add support for Score target.
  72
  73 * ELF: Add --dynamic-list option to specify a list of global symbols
  74   whose references shouldn't be bound to the definition within the
  75   shared library, or a list of symbols which should be added to the
  76   symbol table in the executable.
  77
  78 * The default output section LMA has changed for allocatable sections from
  79   being equal to VMA, to keeping the difference between LMA and VMA the same as
  80   the previous output section in the same region.  This is a more useful
  81   default when using overlays and other cases where you specify an LMA
  82   differing from the VMA for some sections.
  83
  84 * New switch: --print-gc-sections to list any sections removed by garabge
  85   collection.
  86
  87 * ARM: Added --vfp11-denorm-fix option to work around an erratum in current
  88   VFP11 coprocessors.
  89
  90 Changes in 2.17:
  91
  92 * Support for the Infineon XC16X has been added by KPIT Cummins Infosystems.
  93
  94 * Modify the Linux linker search order to better match ld.so search order.
  95   Look for DT_NEEDED libraries in paths specified by ld.so.conf before
  96   searching the default directories, rather than vice versa.
  97   Use $prefix/etc/ld.so.conf if it exists, otherwise /etc/ld.so.conf.
  98
  99 * PE-COFF: Forward exports from DLL's can now be specified in .def files
 100   passed directly to ld.
 101
 102 * Support for the Z80 processor family has been added.
 103
 104 * Add support for the "@<file>" syntax to the command line, so that extra
 105   switches can be read from <file>.
 106
 107 Changes in 2.16:
 108
 109 * Support for the R_ARM_V4BX relocation as defined in the ARM AAELF
 110   specification has been added via the --fix-v4bx command-line option.
 111
 112 * New linker script construct AS_NEEDED(), which sets the --as-needed flag
 113   for input files listed inside of it.
 114
 115 * A new command-line option, --sysroot, can be used to override the
 116   default sysroot location.  It only applies to toolchains that were
 117   configured using --with-sysroot.
 118
 119 * New linker script functions: ORIGIN() and LENGTH() which return information
 120   about a specified memory region.
 121
 122 * Port to MAXQ processor contributed by HCL Tech.
 123
 124 * Added SEGMENT_START to the linker script language to permit the user to
 125   override the base address for a segment from the command-line.
 126
 127 * ELF: --warn-shared-textrel option to warn if adding a DT_TEXTREL to a shared
 128   object.
 129
 130 * Added SORT_BY_NAME and SORT_BY_ALIGNMENT to the linker script
 131   language to permit sorting sections by section name or section
 132   maximum alignment.
 133
 134 * Added a new linker command line switch, --sort-section name|alignment,
 135   to sort sections by section name or maximum alignment.
 136
 137 * ELF: --add-needed/--no-add-needed options to control if a DT_NEEDED tag
 138   should be added when a shared library comes from DT_NEEDED tags.
 139
 140 * Support for the crx-elf target added.
 141
 142 * Support for the sh-symbianelf target added.
 143
 144 * A new linker command line switch has been added which allows the hash table
 145   size to be set to a suitable prime value near to its argument.  This switch
 146   is --hash-size=<NUMBER>.  Also if the switch --reduce-memory-overheads is
 147   used, and --hash-size has not been used, then the default value will be set
 148   to 1021.
 149
 150 * Linker map files are now generated with an O(N) algorithm for finding symbols
 151   that are defined in each section.  This uses about 40% more memory for
 152   symbols than the old O(N^2) algorithm.  You can use the new
 153   --reduce-memory-overheads option to select the old algorithm; this option
 154   might also be used in the future to select similar tradeoffs.
 155
 156 Changes in 2.15:
 157
 158 * ELF: --as-needed/--no-as-needed options to control if a DT_NEEDED tag should
 159   be added only when a shared library is referenced.
 160
 161 * PE: --large-address-aware option to indicate executables support virtual
 162   addresses greater than 2 gigabytes.
 163
 164 * DWARF 2 support for i386pe added.
 165
 166 * The linker script operator DEFINED() will now yield 1 only for a symbol that
 167   is defined before the statement where DEFINED is used.
 168
 169 * The MIPS --embedded-relocs (used to embed relocations into binaries for
 170   Embedded-PIC code) is deprecated and will be removed in a future release.
 171
 172 * cr16c support added by NSC.
 173
 174 * m32r Linux (ELF) support added by Renesas.
 175
 176 * Improved linker's handling of unresolved symbols.  The switch
 177   --unresolved-symbols=<method> has been added to tell the linker when it
 178   should report them and the switch --warn-unresolved-symbols has been added to
 179   make reports be issued as warning messages rather than errors.
 180
 181 Changes in 2.14:
 182
 183 * Added support for Xtensa architecture.
 184
 185 * Added --with-sysroot configure switch to specify a target system root, for
 186   linking against a target filesystem image.
 187
 188 * Added --accept-unknown-linker-format to restore old linker behaviour (pre
 189   2.14) of silently accepting and linking in any files in an unknown binary
 190   file format.
 191
 192 * Added --no-omagic to undo the effects of the -N option.
 193
 194 * Support for Texas Instruments TMS320C4x and TMS320C3x series of
 195   DSP's contributed by Michael Hayes and Svein E. Seldal.
 196
 197 * Added --with-lib-path configure switch to specify default value for
 198   LIB_PATH.
 199
 200 * ARM port to QNX operating system added by Graeme Peterson.
 201
 202 * IP2K support added by Denis Chertykov.
 203
 204 Changes in 2.13:
 205
 206 * Support for the Fujitsu FRV architecture added by Red Hat. Models for FR400
 207   and FR500 included.
 208
 209 Changes in version 2.13:
 210
 211 * DEC VAX ELF support, by Matt Thomas.
 212
 213 Changes in version 2.12:
 214
 215 * Support for Don Knuth's MMIX, by Hans-Peter Nilsson.
 216
 217 * Support for the OpenRISC 32-bit embedded processor by OpenCores.
 218
 219 * Support for -z nocopyreloc in the x86 ELF linker, which disables
 220   production of copy relocs.  Warning: using this option may result in
 221   non-sharable applications.
 222
 223 * Support for -z combreloc in the ELF linker, which puts dynamic
 224   relocations against the same symbol together, so that dynamic linker
 225   can use an one-entry symbol lookup cache.
 226
 227 * Support for ELF SHF_MERGE section merging, by Jakub Jelinek.
 228
 229 Changes in version 2.11:
 230
 231 * Support for AMD x86-64 architecture, by Jan Hubicka, SuSE Labs.
 232
 233 * Support added for eliminating duplicate DWARF2 debug information by
 234   having the compiler generate the information in sections called
 235   .gnu.linkonce.wi.XXXX where XXXX is a checksum for the contents.  The
 236   linker then merges these sections together into the normal .debug_info
 237   section.
 238
 239 * The native ELF linker now searches the directories in DT_RUNPATH or
 240   DT_RPATH of a shared library for shared libraries needed by it.
 241
 242 * TI C54x support, by Timothy Wall.
 243
 244 * Added command line switch --section-start to set the start address of any
 245   specified section.
 246
 247 * Added ability to emit full relocation information in linked executables,
 248   enabled by --emit-relocs.  Some post-linkage optimization tools need
 249   this information in order to be able to correctly identify and perform
 250   symbol relative addressing in the event of changes in section contents
 251   (instructions being added or deleted, extending data sections, etc.)
 252
 253 * Support for i860, by Jason Eckhardt (preliminary, alpha quality).
 254
 255 * Support for CRIS (Axis Communications ETRAX series).
 256
 257 * Support for PDP-11 and 2.11BSD a.out format, by Lars Brinkhoff.
 258
 259 Changes in version 2.10:
 260
 261 * Added AT> to the linker script language to allow load-time allocation of
 262   sections into regions.
 263
 264 * Added garbage collection of unused sections, enabled by --gc-sections.
 265   It does require a bit of backend support; currently implemented are
 266   arm-elf, avr-elf, d10v-elf, fr30-elf, i386-elf, m32r-elf, m68k-elf,
 267   mcore-elf, mips-elf, mn10300-elf, ppc-elf, sh-elf, sparc-elf, and v850-elf.
 268   Others will ignore the option.
 269
 270 * Added SORT to the linker script language to permit sorting sections by file
 271   name or section name.
 272
 273 * Added EXTERN to the linker script language as an equivalent to the -u
 274   command-line option.
 275
 276 * Added ASSERT to the linker script language.
 277
 278 * Added EXCLUDE_FILE to the linker script language for further control over
 279   wildcard file names.
 280
 281 * Added -O option to optimize linker output (as of this writing, this only
 282   affects ELF shared library generation).
 283
 284 * The -e option now accepts a number as well as a symbol name.
 285
 286 * Added --no-undefined option to disallow undefined symbols when creating a
 287   shared library.
 288
 289 * The linker now issues a warning, not an error, for an undefined symbol when
 290   using -Bsymbolic; use the new --no-undefined option to get the old
 291   behaviour.
 292
 293 * Added --demangle and --no-demangle options.
 294
 295 Changes in version 2.9:
 296
 297 * Added SQUAD to the linker script language.
 298
 299 * New option --no-warn-mismatch.
 300
 301 * The MEMORY command now parses the attributes to determine where sections that
 302   are not placed in a specific memory region are placed.
 303
 304 Changes in version 2.8:
 305
 306 * Linker scripts may now contain shell wildcard characters for file and section
 307   names.
 308
 309 * The linker now supports symbol versions in ELF.
 310
 311 * The NOCROSSREFS command was added to the linker script language.
 312
 313 * The LOADADDR expression was added to the linker script language.
 314
 315 * MAX and MIN functions were added to the linker script language.
 316
 317 * The OVERLAY construct was added to the linker script language.
 318
 319 * New option --warn-section-align to warn when the address of an output section
 320   changes due to alignment of an input section.
 321
 322 * New options --filter/-F and --auxiliary/-f.
 323
 324 Changes in version 2.7:
 325
 326 * New option --cref to print out a cross reference table.
 327
 328 * New option --wrap SYMBOL.
 329
 330 * New option --no-whole-archive, to turn off the effect of --whole-archive.
 331
 332 * Input sections assigned to the output section /DISCARD/ in the linker script
 333   are not included in the output file.
 334
 335 * The SunOS and ELF linkers now merge stabs debugging information which uses
 336   the N_BINCL and N_EINCL stab types.  This reduces the amount of debugging
 337   information generated.
 338
 339 Changes in version 2.6:
 340
 341 * When an ELF section name is representable as a C identifier (this is not true
 342 of most ELF section names), the linker will automatically define symbols
 343 __start_SECNAME and __stop_SECNAME, where SECNAME is the section name, at the
 344 beginning and the end of the section.  This is used by glibc.
 345
 346   Addendum: Current versions of the linker (at least for version 2.18 onwards
 347 and possibly much earlier as well) place two restrictions on this feature:  The
 348 symbols are only implemented for orphaned sections, not for explicitly placed
 349 sections and they are PROVIDEd rather than being defined.
 350
 351 * When an ELF section named .gnu.warning is encountered in an input file, the
 352 contents of the section are displayed as an error message, and the section is
 353 not copied into the output file.  This is used by glibc.
 354
 355 * When an ELF section named .gnu.warning.SYMBOL is encountered in an input
 356 file, and the symbol SYMBOL is referenced by some object file, the contents of
 357 the section are displayed as an error message.  The section is not copied into
 358 the output file, unless doing a relocatable or shared link.  This is used by
 359 glibc.
 360
 361 * New options -split-by-reloc and -split-by-file.
 362
 363 * The linker now supports linking PIC compiled code on SPARC SunOS.  It can
 364 also create SPARC SunOS shared libraries, and, like the native SunOS linker,
 365 will do so whenever there is an undefined symbol in the link and neither the -e
 366 nor the -r option was used.
 367
 368 * The -rpath option may be used on SunOS to set the list of directories to be
 369 searched at run time.  This overrides the default of building the list from the
 370 -L options.
 371
 372 * The COFF linker now combines debugging information for structs, unions, and
 373 enums, so that even if the same type is defined in multiple input files it will
 374 only be defined once in the output file.  The --traditional-format switch will
 375 prevent this optimization.
 376
 377 Changes in version 2.5:
 378
 379 * The linker now supports linking against SunOS shared libraries.  It still can
 380 not link SunOS PIC (Position Independent Code) files, so it can not be used to
 381 generate shared libraries.
 382
 383 * The linker now supports linking against ELF shared libraries for the i386
 384 (UnixWare) and SPARC (Solaris).  It can also link ELF PIC files, and can be
 385 used to generate shared libraries.  Shared library generation is not well
 386 tested; please report any problems encountered.  The linker is now enabled for
 387 Solaris again.
 388
 389 * Eric Youngdale has contributed Linux support code, including linking against
 390 Linux a.out shared libraries.  The linker produces Linux QMAGIC binaries.
 391
 392 * The ELF backend has been converted to the new linker code.  To use the new
 393 ELF linker, each particular target requires a relocation function.  So far,
 394 this function has been written for i386 (UnixWare), SPARC (Solaris) MIPS (Irix
 395 5), and HPPA ELF targets.
 396
 397 * The -( (--start-group) and -) (--end-group) options have been added to
 398 support searching a group of archives as though they were a single archive.
 399 This can also be used in a linker script, as GROUP ( files ).
 400
 401 * When a file is named on the command line, and the linker does not recognize
 402 it as an object file, the linker will now treat the file as a linker script
 403 file.  A linker script named in this way augments, but does not replace, the
 404 default linker script.
 405
 406 * The -warn-once option was added.  It causes the linker to only warn once per
 407 undefined symbol, rather than once per reference.
 408
 409 * The COFF backend has been converted to the new linker code.  As with ELF, to
 410 use the new linker, each particular target requires a relocation function.  So
 411 far, this function has been written for the i386, m68k, a29k and SH targets.
 412
 413 * The -V flag was made a synonym for -v, for SVR4 compatibility.  The old -V
 414 behaviour is available via --verbose.
 415
 416 Changes in version 2.4:
 417
 418 * New linker code, by Steve Chamberlain and Ian Taylor.  For a.out and ecoff
 419   formats (so far), this should result in considerable savings in time
 420   and memory used while linking; slightly poorer performance than
 421   before for formats not converted yet.
 422
 423 * Command-line parsing is no longer done with flex.  This means
 424   oddball characters in filenames won't get treated as argument
 425   separators.
 426
 427 * HP-PA ELF support, by Jeff Law.  (No SOM support yet.)
 428
 429 * Mach i386 support, by David Mackenzie.
 430
 431 * Irix 4 shared libraries are now supported (Irix 5 uses ELF, and ELF shared
 432   libraries are not yet supported).
 433
 434 * COFF shared libraries (as on SCO) should work as well.
 435
 436 * The linker is disabled for Solaris.  (Actually, it was in 2.3 also, I just
 437   forgot to note it.)  Some of their C library routines don't work when
 438   statically linked, and the GNU linker doesn't support dynamic linking yet.
 439
 440 Changes in version 2.3:
 441
 442 * Weak symbols are now supported.
 443
 444 * ELF support has been added.  The linker has been bootstrapped on
 445   UnixWare and Solaris.
 446
 447 * Alpha OSF/1 support has been added (non dynamic linking only).
 448
 449 Changes in version 2.2:
 450
 451 * The `bfd' library has been updated to reduce a.out-format string
 452   table size.  The effect of this is that files linked from many input
 453   files with duplicate symbols (`-g' debugging records, or identical
 454   static symbols) should be much smaller.
 455
 456 Changes in version 2.1:
 457
 458 * The ld -ySYMBOL flag (to trace references to SYMBOL) is now implemented.
 459
 460 * There is now support for writing ECOFF files, so ld and the
 461   other utilities should work on Risc/Ultrix and Irix.
 462
 463 \f
 464 Local variables:
 465 fill-column: 79
 466 End: