ld/NEWS

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