ld/NEWS

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