ld/NEWS

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