ld/NEWS

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