ld/NEWS

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