ld/NEWS

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