ld/NEWS

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