ld/NEWS

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