ld/NEWS

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