ld/NEWS

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