2 * ELF: Add --dynamic-list option to specify a list of global symbols
3 whose references shouldn't be bound to the definition within the
4 shared library, or a list of symbols which should be added to the
5 symbol table in the executable.
7 * The default output section LMA has changed for allocatable sections from
8 being equal to VMA, to keeping the difference between LMA and VMA the same as
9 the previous output section in the same region. This is a more useful
10 default when using overlays and other cases where you specify an LMA
11 differing from the VMA for some sections.
13 * New switch: --print-gc-sections to list any sections removed by garabge
18 * Support for the Infineon XC16X has been added by KPIT Cummins Infosystems.
20 * Modify the Linux linker search order to better match ld.so search order.
21 Look for DT_NEEDED libraries in paths specified by ld.so.conf before
22 searching the default directories, rather than vice versa.
23 Use $prefix/etc/ld.so.conf if it exists, otherwise /etc/ld.so.conf.
25 * PE-COFF: Forward exports from DLL's can now be specified in .def files
26 passed directly to ld.
28 * Support for the Z80 processor family has been added.
30 * Add support for the "@<file>" syntax to the command line, so that extra
31 switches can be read from <file>.
35 * Support for the R_ARM_V4BX relocation as defined in the ARM AAELF
36 specification has been added via the --fix-v4bx command-line option.
38 * New linker script construct AS_NEEDED(), which sets the --as-needed flag
39 for input files listed inside of it.
41 * A new command-line option, --sysroot, can be used to override the
42 default sysroot location. It only applies to toolchains that were
43 configured using --with-sysroot.
45 * New linker script functions: ORIGIN() and LENGTH() which return information
46 about a specified memory region.
48 * Port to MAXQ processor contributed by HCL Tech.
50 * Added SEGMENT_START to the linker script language to permit the user to
51 override the base address for a segment from the command-line.
53 * ELF: --warn-shared-textrel option to warn if adding a DT_TEXTREL to a shared
56 * Added SORT_BY_NAME and SORT_BY_ALIGNMENT to the linker script
57 language to permit sorting sections by section name or section
60 * Added a new linker command line switch, --sort-section name|alignment,
61 to sort sections by section name or maximum alignment.
63 * ELF: --add-needed/--no-add-needed options to control if a DT_NEEDED tag
64 should be added when a shared library comes from DT_NEEDED tags.
66 * Support for the crx-elf target added.
68 * Support for the sh-symbianelf target added.
70 * A new linker command line switch has been added which allows the hash table
71 size to be set to a suitable prime value near to its argument. This switch
72 is --hash-size=<NUMBER>. Also if the switch --reduce-memory-overheads is
73 used, and --hash-size has not been used, then the default value will be set
76 * Linker map files are now generated with an O(N) algorithm for finding symbols
77 that are defined in each section. This uses about 40% more memory for
78 symbols than the old O(N^2) algorithm. You can use the new
79 --reduce-memory-overheads option to select the old algorithm; this option
80 might also be used in the future to select similar tradeoffs.
84 * ELF: --as-needed/--no-as-needed options to control if a DT_NEEDED tag should
85 be added only when a shared library is referenced.
87 * PE: --large-address-aware option to indicate executables support virtual
88 addresses greater than 2 gigabytes.
90 * DWARF 2 support for i386pe added.
92 * The linker script operator DEFINED() will now yield 1 only for a symbol that
93 is defined before the statement where DEFINED is used.
95 * The MIPS --embedded-relocs (used to embed relocations into binaries for
96 Embedded-PIC code) is deprecated and will be removed in a future release.
98 * cr16c support added by NSC.
100 * m32r Linux (ELF) support added by Renesas.
102 * Improved linker's handling of unresolved symbols. The switch
103 --unresolved-symbols=<method> has been added to tell the linker when it
104 should report them and the switch --warn-unresolved-symbols has been added to
105 make reports be issued as warning messages rather than errors.
109 * Added support for Xtensa architecture.
111 * Added --with-sysroot configure switch to specify a target system root, for
112 linking against a target filesystem image.
114 * Added --accept-unknown-linker-format to restore old linker behaviour (pre
115 2.14) of silently accepting and linking in any files in an unknown binary
118 * Added --no-omagic to undo the effects of the -N option.
120 * Support for Texas Instruments TMS320C4x and TMS320C3x series of
121 DSP's contributed by Michael Hayes and Svein E. Seldal.
123 * Added --with-lib-path configure switch to specify default value for
126 * ARM port to QNX operating system added by Graeme Peterson.
128 * IP2K support added by Denis Chertykov.
132 * Support for the Fujitsu FRV architecture added by Red Hat. Models for FR400
135 Changes in version 2.13:
137 * DEC VAX ELF support, by Matt Thomas.
139 Changes in version 2.12:
141 * Support for Don Knuth's MMIX, by Hans-Peter Nilsson.
143 * Support for the OpenRISC 32-bit embedded processor by OpenCores.
145 * Support for -z nocopyreloc in the x86 ELF linker, which disables
146 production of copy relocs. Warning: using this option may result in
147 non-sharable applications.
149 * Support for -z combreloc in the ELF linker, which puts dynamic
150 relocations against the same symbol together, so that dynamic linker
151 can use an one-entry symbol lookup cache.
153 * Support for ELF SHF_MERGE section merging, by Jakub Jelinek.
155 Changes in version 2.11:
157 * Support for AMD x86-64 architecture, by Jan Hubicka, SuSE Labs.
159 * Support added for eliminating duplicate DWARF2 debug information by
160 having the compiler generate the information in sections called
161 .gnu.linkonce.wi.XXXX where XXXX is a checksum for the contents. The
162 linker then merges these sections together into the normal .debug_info
165 * The native ELF linker now searches the directories in DT_RUNPATH or
166 DT_RPATH of a shared library for shared libraries needed by it.
168 * TI C54x support, by Timothy Wall.
170 * Added command line switch --section-start to set the start address of any
173 * Added ability to emit full relocation information in linked executables,
174 enabled by --emit-relocs. Some post-linkage optimization tools need
175 this information in order to be able to correctly identify and perform
176 symbol relative addressing in the event of changes in section contents
177 (instructions being added or deleted, extending data sections, etc.)
179 * Support for i860, by Jason Eckhardt (preliminary, alpha quality).
181 * Support for CRIS (Axis Communications ETRAX series).
183 * Support for PDP-11 and 2.11BSD a.out format, by Lars Brinkhoff.
185 Changes in version 2.10:
187 * Added AT> to the linker script language to allow load-time allocation of
188 sections into regions.
190 * Added garbage collection of unused sections, enabled by --gc-sections.
191 It does require a bit of backend support; currently implemented are
192 arm-elf, avr-elf, d10v-elf, fr30-elf, i386-elf, m32r-elf, m68k-elf,
193 mcore-elf, mips-elf, mn10300-elf, ppc-elf, sh-elf, sparc-elf, and v850-elf.
194 Others will ignore the option.
196 * Added SORT to the linker script language to permit sorting sections by file
197 name or section name.
199 * Added EXTERN to the linker script language as an equivalent to the -u
202 * Added ASSERT to the linker script language.
204 * Added EXCLUDE_FILE to the linker script language for further control over
207 * Added -O option to optimize linker output (as of this writing, this only
208 affects ELF shared library generation).
210 * The -e option now accepts a number as well as a symbol name.
212 * Added --no-undefined option to disallow undefined symbols when creating a
215 * The linker now issues a warning, not an error, for an undefined symbol when
216 using -Bsymbolic; use the new --no-undefined option to get the old
219 * Added --demangle and --no-demangle options.
221 Changes in version 2.9:
223 * Added SQUAD to the linker script language.
225 * New option --no-warn-mismatch.
227 * The MEMORY command now parses the attributes to determine where sections that
228 are not placed in a specific memory region are placed.
230 Changes in version 2.8:
232 * Linker scripts may now contain shell wildcard characters for file and section
235 * The linker now supports symbol versions in ELF.
237 * The NOCROSSREFS command was added to the linker script language.
239 * The LOADADDR expression was added to the linker script language.
241 * MAX and MIN functions were added to the linker script language.
243 * The OVERLAY construct was added to the linker script language.
245 * New option --warn-section-align to warn when the address of an output section
246 changes due to alignment of an input section.
248 * New options --filter/-F and --auxiliary/-f.
250 Changes in version 2.7:
252 * New option --cref to print out a cross reference table.
254 * New option --wrap SYMBOL.
256 * New option --no-whole-archive, to turn off the effect of --whole-archive.
258 * Input sections assigned to the output section /DISCARD/ in the linker script
259 are not included in the output file.
261 * The SunOS and ELF linkers now merge stabs debugging information which uses
262 the N_BINCL and N_EINCL stab types. This reduces the amount of debugging
263 information generated.
265 Changes in version 2.6:
267 * When an ELF section name is representable as a C identifier (this is not true
268 of most ELF section names), the linker will automatically define symbols
269 __start_SECNAME and __stop_SECNAME, where SECNAME is the section name, at the
270 beginning and the end of the section. This is used by glibc.
272 * When an ELF section named .gnu.warning is encountered in an input file, the
273 contents of the section are displayed as an error message, and the section is
274 not copied into the output file. This is used by glibc.
276 * When an ELF section named .gnu.warning.SYMBOL is encountered in an input
277 file, and the symbol SYMBOL is referenced by some object file, the contents of
278 the section are displayed as an error message. The section is not copied into
279 the output file, unless doing a relocatable or shared link. This is used by
282 * New options -split-by-reloc and -split-by-file.
284 * The linker now supports linking PIC compiled code on SPARC SunOS. It can
285 also create SPARC SunOS shared libraries, and, like the native SunOS linker,
286 will do so whenever there is an undefined symbol in the link and neither the -e
287 nor the -r option was used.
289 * The -rpath option may be used on SunOS to set the list of directories to be
290 searched at run time. This overrides the default of building the list from the
293 * The COFF linker now combines debugging information for structs, unions, and
294 enums, so that even if the same type is defined in multiple input files it will
295 only be defined once in the output file. The --traditional-format switch will
296 prevent this optimization.
298 Changes in version 2.5:
300 * The linker now supports linking against SunOS shared libraries. It still can
301 not link SunOS PIC (Position Independent Code) files, so it can not be used to
302 generate shared libraries.
304 * The linker now supports linking against ELF shared libraries for the i386
305 (UnixWare) and SPARC (Solaris). It can also link ELF PIC files, and can be
306 used to generate shared libraries. Shared library generation is not well
307 tested; please report any problems encountered. The linker is now enabled for
310 * Eric Youngdale has contributed Linux support code, including linking against
311 Linux a.out shared libraries. The linker produces Linux QMAGIC binaries.
313 * The ELF backend has been converted to the new linker code. To use the new
314 ELF linker, each particular target requires a relocation function. So far,
315 this function has been written for i386 (UnixWare), SPARC (Solaris) MIPS (Irix
316 5), and HPPA ELF targets.
318 * The -( (--start-group) and -) (--end-group) options have been added to
319 support searching a group of archives as though they were a single archive.
320 This can also be used in a linker script, as GROUP ( files ).
322 * When a file is named on the command line, and the linker does not recognize
323 it as an object file, the linker will now treat the file as a linker script
324 file. A linker script named in this way augments, but does not replace, the
325 default linker script.
327 * The -warn-once option was added. It causes the linker to only warn once per
328 undefined symbol, rather than once per reference.
330 * The COFF backend has been converted to the new linker code. As with ELF, to
331 use the new linker, each particular target requires a relocation function. So
332 far, this function has been written for the i386, m68k, a29k and SH targets.
334 * The -V flag was made a synonym for -v, for SVR4 compatibility. The old -V
335 behaviour is available via --verbose.
337 Changes in version 2.4:
339 * New linker code, by Steve Chamberlain and Ian Taylor. For a.out and ecoff
340 formats (so far), this should result in considerable savings in time
341 and memory used while linking; slightly poorer performance than
342 before for formats not converted yet.
344 * Command-line parsing is no longer done with flex. This means
345 oddball characters in filenames won't get treated as argument
348 * HP-PA ELF support, by Jeff Law. (No SOM support yet.)
350 * Mach i386 support, by David Mackenzie.
352 * Irix 4 shared libraries are now supported (Irix 5 uses ELF, and ELF shared
353 libraries are not yet supported).
355 * COFF shared libraries (as on SCO) should work as well.
357 * The linker is disabled for Solaris. (Actually, it was in 2.3 also, I just
358 forgot to note it.) Some of their C library routines don't work when
359 statically linked, and the GNU linker doesn't support dynamic linking yet.
361 Changes in version 2.3:
363 * Weak symbols are now supported.
365 * ELF support has been added. The linker has been bootstrapped on
366 UnixWare and Solaris.
368 * Alpha OSF/1 support has been added (non dynamic linking only).
370 Changes in version 2.2:
372 * The `bfd' library has been updated to reduce a.out-format string
373 table size. The effect of this is that files linked from many input
374 files with duplicate symbols (`-g' debugging records, or identical
375 static symbols) should be much smaller.
377 Changes in version 2.1:
379 * The ld -ySYMBOL flag (to trace references to SYMBOL) is now implemented.
381 * There is now support for writing ECOFF files, so ld and the
382 other utilities should work on Risc/Ultrix and Irix.