ld/NEWS

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