ld/NEWS

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