ld/NEWS

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