ld/NEWS

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