ld/NEWS

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