ld/NEWS

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