ld/NEWS

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