ld/NEWS

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