ld/NEWS

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