ld/NEWS

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