ld/NEWS

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