3 * PE targets no longer make use of the long section names PE extension to
4 the COFF format when generating executable images, by default. The old
5 (slightly non-conformant) behaviour can still be invoked by using the
6 new '--enable-long-section-names' command-line option.
8 * --as-needed now links in a dynamic library if it satisfies undefined
9 symbols in regular objects, or in other dynamic libraries. In the
10 latter case the library is not linked if it is found in a DT_NEEDED
11 entry of one of the libraries already linked.
13 * Add a new command line option, -Ttext-segment ADDR, for ELF targets
14 to set the address of the first byte of the text segment.
16 * Add support for Sunplus score architecture.
18 * Add new option --use-nul-prefixed-import-tables to ld for PE targets to
19 allow fallback to old import table generation with null element prefix.
21 * Windows PE systems now support a new --exclude-modules-for-implib option,
22 allowing users to partition object files and archive members between a DLL
23 and its associated import library as they are generated during linking.
25 * Add support for Lattice Mico32 (lm32) architecture.
27 * Add CR16 ELF --embedded-relocs (used to embedded relocations into binaries
28 for Embedded-PIC code) option.
30 * Add to the PE/PE+ targets the support of two different kinds of
31 pseudo-relocations. They can be selected by the switches
32 --enable-runtime-pseudo-reloc-v1 and --enable-runtime-pseudo-reloc-v2.
33 For the switch --enable-runtime-pseudo-reloc it uses for 32-bit
34 runtime pseudo relocation version one, for 64-bit the version two.
38 * Linker scripts support a new INSERT command that makes it easier to
39 augment the default script.
41 * Linker script input section filespecs may now specify a file within an
42 archive by writing "archive:file".
44 * The --sort-common switch now has an optional argument which specifies the
47 * The M68K linker now supports multiple GOT generation schemes controlled via
48 the --got=<type> command line option.
50 * The ARM EABI linker will now generate stubs for function calls to symbols
51 that are too far away. The placement of the stubs is controlled by a new
52 linker command line option: --stub-group-size=N.
56 * Linker sources now released under version 3 of the GNU General Public
59 * ELF: New --build-id option to generate a unique per-binary identifier
60 embedded in a note section.
62 * Added support for National Semicondutor CompactRISC (ie CR16) target.
64 * -l:foo now searches the library path for a filename called foo,
65 without converting it to libfoo.a or libfoo.so.
67 * Add a new command line option '--default-script=FILE' or '-dT FILE'
68 which specifies a replacement for the built in, default linker
71 * ELF: Add -Bsymbolic-functions, --dynamic-list-cpp-new, which puts C++
72 operator new and delete on the dynamic list, and --dynamic-list-data,
73 builtin list for --dynamic-list, which puts global data symbols on the
76 * Add support for x86_64 PE+ target.
78 * Add support for Score target.
80 * ELF: Add --dynamic-list option to specify a list of global symbols
81 whose references shouldn't be bound to the definition within the
82 shared library, or a list of symbols which should be added to the
83 symbol table in the executable.
85 * The default output section LMA has changed for allocatable sections from
86 being equal to VMA, to keeping the difference between LMA and VMA the same as
87 the previous output section in the same region. This is a more useful
88 default when using overlays and other cases where you specify an LMA
89 differing from the VMA for some sections.
91 * New switch: --print-gc-sections to list any sections removed by garabge
94 * ARM: Added --vfp11-denorm-fix option to work around an erratum in current
99 * Support for the Infineon XC16X has been added by KPIT Cummins Infosystems.
101 * Modify the Linux linker search order to better match ld.so search order.
102 Look for DT_NEEDED libraries in paths specified by ld.so.conf before
103 searching the default directories, rather than vice versa.
104 Use $prefix/etc/ld.so.conf if it exists, otherwise /etc/ld.so.conf.
106 * PE-COFF: Forward exports from DLL's can now be specified in .def files
107 passed directly to ld.
109 * Support for the Z80 processor family has been added.
111 * Add support for the "@<file>" syntax to the command line, so that extra
112 switches can be read from <file>.
116 * Support for the R_ARM_V4BX relocation as defined in the ARM AAELF
117 specification has been added via the --fix-v4bx command-line option.
119 * New linker script construct AS_NEEDED(), which sets the --as-needed flag
120 for input files listed inside of it.
122 * A new command-line option, --sysroot, can be used to override the
123 default sysroot location. It only applies to toolchains that were
124 configured using --with-sysroot.
126 * New linker script functions: ORIGIN() and LENGTH() which return information
127 about a specified memory region.
129 * Port to MAXQ processor contributed by HCL Tech.
131 * Added SEGMENT_START to the linker script language to permit the user to
132 override the base address for a segment from the command-line.
134 * ELF: --warn-shared-textrel option to warn if adding a DT_TEXTREL to a shared
137 * Added SORT_BY_NAME and SORT_BY_ALIGNMENT to the linker script
138 language to permit sorting sections by section name or section
141 * Added a new linker command line switch, --sort-section name|alignment,
142 to sort sections by section name or maximum alignment.
144 * ELF: --add-needed/--no-add-needed options to control if a DT_NEEDED tag
145 should be added when a shared library comes from DT_NEEDED tags.
147 * Support for the crx-elf target added.
149 * Support for the sh-symbianelf target added.
151 * A new linker command line switch has been added which allows the hash table
152 size to be set to a suitable prime value near to its argument. This switch
153 is --hash-size=<NUMBER>. Also if the switch --reduce-memory-overheads is
154 used, and --hash-size has not been used, then the default value will be set
157 * Linker map files are now generated with an O(N) algorithm for finding symbols
158 that are defined in each section. This uses about 40% more memory for
159 symbols than the old O(N^2) algorithm. You can use the new
160 --reduce-memory-overheads option to select the old algorithm; this option
161 might also be used in the future to select similar tradeoffs.
165 * ELF: --as-needed/--no-as-needed options to control if a DT_NEEDED tag should
166 be added only when a shared library is referenced.
168 * PE: --large-address-aware option to indicate executables support virtual
169 addresses greater than 2 gigabytes.
171 * DWARF 2 support for i386pe added.
173 * The linker script operator DEFINED() will now yield 1 only for a symbol that
174 is defined before the statement where DEFINED is used.
176 * The MIPS --embedded-relocs (used to embed relocations into binaries for
177 Embedded-PIC code) is deprecated and will be removed in a future release.
179 * cr16c support added by NSC.
181 * m32r Linux (ELF) support added by Renesas.
183 * Improved linker's handling of unresolved symbols. The switch
184 --unresolved-symbols=<method> has been added to tell the linker when it
185 should report them and the switch --warn-unresolved-symbols has been added to
186 make reports be issued as warning messages rather than errors.
190 * Added support for Xtensa architecture.
192 * Added --with-sysroot configure switch to specify a target system root, for
193 linking against a target filesystem image.
195 * Added --accept-unknown-linker-format to restore old linker behaviour (pre
196 2.14) of silently accepting and linking in any files in an unknown binary
199 * Added --no-omagic to undo the effects of the -N option.
201 * Support for Texas Instruments TMS320C4x and TMS320C3x series of
202 DSP's contributed by Michael Hayes and Svein E. Seldal.
204 * Added --with-lib-path configure switch to specify default value for
207 * ARM port to QNX operating system added by Graeme Peterson.
209 * IP2K support added by Denis Chertykov.
213 * Support for the Fujitsu FRV architecture added by Red Hat. Models for FR400
216 Changes in version 2.13:
218 * DEC VAX ELF support, by Matt Thomas.
220 Changes in version 2.12:
222 * Support for Don Knuth's MMIX, by Hans-Peter Nilsson.
224 * Support for the OpenRISC 32-bit embedded processor by OpenCores.
226 * Support for -z nocopyreloc in the x86 ELF linker, which disables
227 production of copy relocs. Warning: using this option may result in
228 non-sharable applications.
230 * Support for -z combreloc in the ELF linker, which puts dynamic
231 relocations against the same symbol together, so that dynamic linker
232 can use an one-entry symbol lookup cache.
234 * Support for ELF SHF_MERGE section merging, by Jakub Jelinek.
236 Changes in version 2.11:
238 * Support for AMD x86-64 architecture, by Jan Hubicka, SuSE Labs.
240 * Support added for eliminating duplicate DWARF2 debug information by
241 having the compiler generate the information in sections called
242 .gnu.linkonce.wi.XXXX where XXXX is a checksum for the contents. The
243 linker then merges these sections together into the normal .debug_info
246 * The native ELF linker now searches the directories in DT_RUNPATH or
247 DT_RPATH of a shared library for shared libraries needed by it.
249 * TI C54x support, by Timothy Wall.
251 * Added command line switch --section-start to set the start address of any
254 * Added ability to emit full relocation information in linked executables,
255 enabled by --emit-relocs. Some post-linkage optimization tools need
256 this information in order to be able to correctly identify and perform
257 symbol relative addressing in the event of changes in section contents
258 (instructions being added or deleted, extending data sections, etc.)
260 * Support for i860, by Jason Eckhardt (preliminary, alpha quality).
262 * Support for CRIS (Axis Communications ETRAX series).
264 * Support for PDP-11 and 2.11BSD a.out format, by Lars Brinkhoff.
266 Changes in version 2.10:
268 * Added AT> to the linker script language to allow load-time allocation of
269 sections into regions.
271 * Added garbage collection of unused sections, enabled by --gc-sections.
272 It does require a bit of backend support; currently implemented are
273 arm-elf, avr-elf, d10v-elf, fr30-elf, i386-elf, m32r-elf, m68k-elf,
274 mcore-elf, mips-elf, mn10300-elf, ppc-elf, sh-elf, sparc-elf, and v850-elf.
275 Others will ignore the option.
277 * Added SORT to the linker script language to permit sorting sections by file
278 name or section name.
280 * Added EXTERN to the linker script language as an equivalent to the -u
283 * Added ASSERT to the linker script language.
285 * Added EXCLUDE_FILE to the linker script language for further control over
288 * Added -O option to optimize linker output (as of this writing, this only
289 affects ELF shared library generation).
291 * The -e option now accepts a number as well as a symbol name.
293 * Added --no-undefined option to disallow undefined symbols when creating a
296 * The linker now issues a warning, not an error, for an undefined symbol when
297 using -Bsymbolic; use the new --no-undefined option to get the old
300 * Added --demangle and --no-demangle options.
302 Changes in version 2.9:
304 * Added SQUAD to the linker script language.
306 * New option --no-warn-mismatch.
308 * The MEMORY command now parses the attributes to determine where sections that
309 are not placed in a specific memory region are placed.
311 Changes in version 2.8:
313 * Linker scripts may now contain shell wildcard characters for file and section
316 * The linker now supports symbol versions in ELF.
318 * The NOCROSSREFS command was added to the linker script language.
320 * The LOADADDR expression was added to the linker script language.
322 * MAX and MIN functions were added to the linker script language.
324 * The OVERLAY construct was added to the linker script language.
326 * New option --warn-section-align to warn when the address of an output section
327 changes due to alignment of an input section.
329 * New options --filter/-F and --auxiliary/-f.
331 Changes in version 2.7:
333 * New option --cref to print out a cross reference table.
335 * New option --wrap SYMBOL.
337 * New option --no-whole-archive, to turn off the effect of --whole-archive.
339 * Input sections assigned to the output section /DISCARD/ in the linker script
340 are not included in the output file.
342 * The SunOS and ELF linkers now merge stabs debugging information which uses
343 the N_BINCL and N_EINCL stab types. This reduces the amount of debugging
344 information generated.
346 Changes in version 2.6:
348 * When an ELF section name is representable as a C identifier (this is not true
349 of most ELF section names), the linker will automatically define symbols
350 __start_SECNAME and __stop_SECNAME, where SECNAME is the section name, at the
351 beginning and the end of the section. This is used by glibc.
353 Addendum: Current versions of the linker (at least for version 2.18 onwards
354 and possibly much earlier as well) place two restrictions on this feature: The
355 symbols are only implemented for orphaned sections, not for explicitly placed
356 sections and they are PROVIDEd rather than being defined.
358 * When an ELF section named .gnu.warning is encountered in an input file, the
359 contents of the section are displayed as an error message, and the section is
360 not copied into the output file. This is used by glibc.
362 * When an ELF section named .gnu.warning.SYMBOL is encountered in an input
363 file, and the symbol SYMBOL is referenced by some object file, the contents of
364 the section are displayed as an error message. The section is not copied into
365 the output file, unless doing a relocatable or shared link. This is used by
368 * New options -split-by-reloc and -split-by-file.
370 * The linker now supports linking PIC compiled code on SPARC SunOS. It can
371 also create SPARC SunOS shared libraries, and, like the native SunOS linker,
372 will do so whenever there is an undefined symbol in the link and neither the -e
373 nor the -r option was used.
375 * The -rpath option may be used on SunOS to set the list of directories to be
376 searched at run time. This overrides the default of building the list from the
379 * The COFF linker now combines debugging information for structs, unions, and
380 enums, so that even if the same type is defined in multiple input files it will
381 only be defined once in the output file. The --traditional-format switch will
382 prevent this optimization.
384 Changes in version 2.5:
386 * The linker now supports linking against SunOS shared libraries. It still can
387 not link SunOS PIC (Position Independent Code) files, so it can not be used to
388 generate shared libraries.
390 * The linker now supports linking against ELF shared libraries for the i386
391 (UnixWare) and SPARC (Solaris). It can also link ELF PIC files, and can be
392 used to generate shared libraries. Shared library generation is not well
393 tested; please report any problems encountered. The linker is now enabled for
396 * Eric Youngdale has contributed Linux support code, including linking against
397 Linux a.out shared libraries. The linker produces Linux QMAGIC binaries.
399 * The ELF backend has been converted to the new linker code. To use the new
400 ELF linker, each particular target requires a relocation function. So far,
401 this function has been written for i386 (UnixWare), SPARC (Solaris) MIPS (Irix
402 5), and HPPA ELF targets.
404 * The -( (--start-group) and -) (--end-group) options have been added to
405 support searching a group of archives as though they were a single archive.
406 This can also be used in a linker script, as GROUP ( files ).
408 * When a file is named on the command line, and the linker does not recognize
409 it as an object file, the linker will now treat the file as a linker script
410 file. A linker script named in this way augments, but does not replace, the
411 default linker script.
413 * The -warn-once option was added. It causes the linker to only warn once per
414 undefined symbol, rather than once per reference.
416 * The COFF backend has been converted to the new linker code. As with ELF, to
417 use the new linker, each particular target requires a relocation function. So
418 far, this function has been written for the i386, m68k, a29k and SH targets.
420 * The -V flag was made a synonym for -v, for SVR4 compatibility. The old -V
421 behaviour is available via --verbose.
423 Changes in version 2.4:
425 * New linker code, by Steve Chamberlain and Ian Taylor. For a.out and ecoff
426 formats (so far), this should result in considerable savings in time
427 and memory used while linking; slightly poorer performance than
428 before for formats not converted yet.
430 * Command-line parsing is no longer done with flex. This means
431 oddball characters in filenames won't get treated as argument
434 * HP-PA ELF support, by Jeff Law. (No SOM support yet.)
436 * Mach i386 support, by David Mackenzie.
438 * Irix 4 shared libraries are now supported (Irix 5 uses ELF, and ELF shared
439 libraries are not yet supported).
441 * COFF shared libraries (as on SCO) should work as well.
443 * The linker is disabled for Solaris. (Actually, it was in 2.3 also, I just
444 forgot to note it.) Some of their C library routines don't work when
445 statically linked, and the GNU linker doesn't support dynamic linking yet.
447 Changes in version 2.3:
449 * Weak symbols are now supported.
451 * ELF support has been added. The linker has been bootstrapped on
452 UnixWare and Solaris.
454 * Alpha OSF/1 support has been added (non dynamic linking only).
456 Changes in version 2.2:
458 * The `bfd' library has been updated to reduce a.out-format string
459 table size. The effect of this is that files linked from many input
460 files with duplicate symbols (`-g' debugging records, or identical
461 static symbols) should be much smaller.
463 Changes in version 2.1:
465 * The ld -ySYMBOL flag (to trace references to SYMBOL) is now implemented.
467 * There is now support for writing ECOFF files, so ld and the
468 other utilities should work on Risc/Ultrix and Irix.