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