ld/NEWS

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