ld/NEWS

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