ld/NEWS

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