ld/NEWS

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