* Makefile.in (OBS): Add version.o.
[deliverable/binutils-gdb.git] / ld / NEWS
1 -*- text -*-
2
3 * PE-COFF: Forward exports from DLL's can now be specified in .def files
4 passed directly to ld.
5
6 * Support for the Z80 processor family has been added.
7
8 * Add support for the "@<file>" syntax to the command line, so that extra
9 switches can be read from <file>.
10
11 Changes in 2.16:
12
13 * Support for the R_ARM_V4BX relocation as defined in the ARM AAELF
14 specification has been added via the --fix-v4bx command-line option.
15
16 * New linker script construct AS_NEEDED(), which sets the --as-needed flag
17 for input files listed inside of it.
18
19 * A new command-line option, --sysroot, can be used to override the
20 default sysroot location. It only applies to toolchains that were
21 configured using --with-sysroot.
22
23 * New linker script functions: ORIGIN() and LENGTH() which return information
24 about a specified memory region.
25
26 * Port to MAXQ processor contributed by HCL Tech.
27
28 * Added SEGMENT_START to the linker script language to permit the user to
29 override the base address for a segment from the command-line.
30
31 * ELF: --warn-shared-textrel option to warn if adding a DT_TEXTREL to a shared
32 object.
33
34 * Added SORT_BY_NAME and SORT_BY_ALIGNMENT to the linker script
35 language to permit sorting sections by section name or section
36 maximum alignment.
37
38 * Added a new linker command line switch, --sort-section name|alignment,
39 to sort sections by section name or maximum alignment.
40
41 * ELF: --add-needed/--no-add-needed options to control if a DT_NEEDED tag
42 should be added when a shared library comes from DT_NEEDED tags.
43
44 * Support for the crx-elf target added.
45
46 * Support for the sh-symbianelf target added.
47
48 * A new linker command line switch has been added which allows the hash table
49 size to be set to a suitable prime value near to its argument. This switch
50 is --hash-size=<NUMBER>. Also if the switch --reduce-memory-overheads is
51 used, and --hash-size has not been used, then the default value will be set
52 to 1021.
53
54 * Linker map files are now generated with an O(N) algorithm for finding symbols
55 that are defined in each section. This uses about 40% more memory for
56 symbols than the old O(N^2) algorithm. You can use the new
57 --reduce-memory-overheads option to select the old algorithm; this option
58 might also be used in the future to select similar tradeoffs.
59
60 Changes in 2.15:
61
62 * ELF: --as-needed/--no-as-needed options to control if a DT_NEEDED tag should
63 be added only when a shared library is referenced.
64
65 * PE: --large-address-aware option to indicate executables support virtual
66 addresses greater than 2 gigabytes.
67
68 * DWARF 2 support for i386pe added.
69
70 * The linker script operator DEFINED() will now yield 1 only for a symbol that
71 is defined before the statement where DEFINED is used.
72
73 * The MIPS --embedded-relocs (used to embed relocations into binaries for
74 Embedded-PIC code) is deprecated and will be removed in a future release.
75
76 * cr16c support added by NSC.
77
78 * m32r Linux (ELF) support added by Renesas.
79
80 * Improved linker's handling of unresolved symbols. The switch
81 --unresolved-symbols=<method> has been added to tell the linker when it
82 should report them and the switch --warn-unresolved-symbols has been added to
83 make reports be issued as warning messages rather than errors.
84
85 Changes in 2.14:
86
87 * Added support for Xtensa architecture.
88
89 * Added --with-sysroot configure switch to specify a target system root, for
90 linking against a target filesystem image.
91
92 * Added --accept-unknown-linker-format to restore old linker behaviour (pre
93 2.14) of silently accepting and linking in any files in an unknown binary
94 file format.
95
96 * Added --no-omagic to undo the effects of the -N option.
97
98 * Support for Texas Instruments TMS320C4x and TMS320C3x series of
99 DSP's contributed by Michael Hayes and Svein E. Seldal.
100
101 * Added --with-lib-path configure switch to specify default value for
102 LIB_PATH.
103
104 * ARM port to QNX operating system added by Graeme Peterson.
105
106 * IP2K support added by Denis Chertykov.
107
108 Changes in 2.13:
109
110 * Support for the Fujitsu FRV architecture added by Red Hat. Models for FR400
111 and FR500 included.
112
113 Changes in version 2.13:
114
115 * DEC VAX ELF support, by Matt Thomas.
116
117 Changes in version 2.12:
118
119 * Support for Don Knuth's MMIX, by Hans-Peter Nilsson.
120
121 * Support for the OpenRISC 32-bit embedded processor by OpenCores.
122
123 * Support for -z nocopyreloc in the x86 ELF linker, which disables
124 production of copy relocs. Warning: using this option may result in
125 non-sharable applications.
126
127 * Support for -z combreloc in the ELF linker, which puts dynamic
128 relocations against the same symbol together, so that dynamic linker
129 can use an one-entry symbol lookup cache.
130
131 * Support for ELF SHF_MERGE section merging, by Jakub Jelinek.
132
133 Changes in version 2.11:
134
135 * Support for AMD x86-64 architecture, by Jan Hubicka, SuSE Labs.
136
137 * Support added for eliminating duplicate DWARF2 debug information by
138 having the compiler generate the information in sections called
139 .gnu.linkonce.wi.XXXX where XXXX is a checksum for the contents. The
140 linker then merges these sections together into the normal .debug_info
141 section.
142
143 * The native ELF linker now searches the directories in DT_RUNPATH or
144 DT_RPATH of a shared library for shared libraries needed by it.
145
146 * TI C54x support, by Timothy Wall.
147
148 * Added command line switch --section-start to set the start address of any
149 specified section.
150
151 * Added ability to emit full relocation information in linked executables,
152 enabled by --emit-relocs. Some post-linkage optimization tools need
153 this information in order to be able to correctly identify and perform
154 symbol relative addressing in the event of changes in section contents
155 (instructions being added or deleted, extending data sections, etc.)
156
157 * Support for i860, by Jason Eckhardt (preliminary, alpha quality).
158
159 * Support for CRIS (Axis Communications ETRAX series).
160
161 * Support for PDP-11 and 2.11BSD a.out format, by Lars Brinkhoff.
162
163 Changes in version 2.10:
164
165 * Added AT> to the linker script language to allow load-time allocation of
166 sections into regions.
167
168 * Added garbage collection of unused sections, enabled by --gc-sections.
169 It does require a bit of backend support; currently implemented are
170 arm-elf, avr-elf, d10v-elf, fr30-elf, i386-elf, m32r-elf, m68k-elf,
171 mcore-elf, mips-elf, mn10300-elf, ppc-elf, sh-elf, sparc-elf, and v850-elf.
172 Others will ignore the option.
173
174 * Added SORT to the linker script language to permit sorting sections by file
175 name or section name.
176
177 * Added EXTERN to the linker script language as an equivalent to the -u
178 command-line option.
179
180 * Added ASSERT to the linker script language.
181
182 * Added EXCLUDE_FILE to the linker script language for further control over
183 wildcard file names.
184
185 * Added -O option to optimize linker output (as of this writing, this only
186 affects ELF shared library generation).
187
188 * The -e option now accepts a number as well as a symbol name.
189
190 * Added --no-undefined option to disallow undefined symbols when creating a
191 shared library.
192
193 * The linker now issues a warning, not an error, for an undefined symbol when
194 using -Bsymbolic; use the new --no-undefined option to get the old
195 behaviour.
196
197 * Added --demangle and --no-demangle options.
198
199 Changes in version 2.9:
200
201 * Added SQUAD to the linker script language.
202
203 * New option --no-warn-mismatch.
204
205 * The MEMORY command now parses the attributes to determine where sections that
206 are not placed in a specific memory region are placed.
207
208 Changes in version 2.8:
209
210 * Linker scripts may now contain shell wildcard characters for file and section
211 names.
212
213 * The linker now supports symbol versions in ELF.
214
215 * The NOCROSSREFS command was added to the linker script language.
216
217 * The LOADADDR expression was added to the linker script language.
218
219 * MAX and MIN functions were added to the linker script language.
220
221 * The OVERLAY construct was added to the linker script language.
222
223 * New option --warn-section-align to warn when the address of an output section
224 changes due to alignment of an input section.
225
226 * New options --filter/-F and --auxiliary/-f.
227
228 Changes in version 2.7:
229
230 * New option --cref to print out a cross reference table.
231
232 * New option --wrap SYMBOL.
233
234 * New option --no-whole-archive, to turn off the effect of --whole-archive.
235
236 * Input sections assigned to the output section /DISCARD/ in the linker script
237 are not included in the output file.
238
239 * The SunOS and ELF linkers now merge stabs debugging information which uses
240 the N_BINCL and N_EINCL stab types. This reduces the amount of debugging
241 information generated.
242
243 Changes in version 2.6:
244
245 * When an ELF section name is representable as a C identifier (this is not true
246 of most ELF section names), the linker will automatically define symbols
247 __start_SECNAME and __stop_SECNAME, where SECNAME is the section name, at the
248 beginning and the end of the section. This is used by glibc.
249
250 * When an ELF section named .gnu.warning is encountered in an input file, the
251 contents of the section are displayed as an error message, and the section is
252 not copied into the output file. This is used by glibc.
253
254 * When an ELF section named .gnu.warning.SYMBOL is encountered in an input
255 file, and the symbol SYMBOL is referenced by some object file, the contents of
256 the section are displayed as an error message. The section is not copied into
257 the output file, unless doing a relocatable or shared link. This is used by
258 glibc.
259
260 * New options -split-by-reloc and -split-by-file.
261
262 * The linker now supports linking PIC compiled code on SPARC SunOS. It can
263 also create SPARC SunOS shared libraries, and, like the native SunOS linker,
264 will do so whenever there is an undefined symbol in the link and neither the -e
265 nor the -r option was used.
266
267 * The -rpath option may be used on SunOS to set the list of directories to be
268 searched at run time. This overrides the default of building the list from the
269 -L options.
270
271 * The COFF linker now combines debugging information for structs, unions, and
272 enums, so that even if the same type is defined in multiple input files it will
273 only be defined once in the output file. The --traditional-format switch will
274 prevent this optimization.
275
276 Changes in version 2.5:
277
278 * The linker now supports linking against SunOS shared libraries. It still can
279 not link SunOS PIC (Position Independent Code) files, so it can not be used to
280 generate shared libraries.
281
282 * The linker now supports linking against ELF shared libraries for the i386
283 (UnixWare) and SPARC (Solaris). It can also link ELF PIC files, and can be
284 used to generate shared libraries. Shared library generation is not well
285 tested; please report any problems encountered. The linker is now enabled for
286 Solaris again.
287
288 * Eric Youngdale has contributed Linux support code, including linking against
289 Linux a.out shared libraries. The linker produces Linux QMAGIC binaries.
290
291 * The ELF backend has been converted to the new linker code. To use the new
292 ELF linker, each particular target requires a relocation function. So far,
293 this function has been written for i386 (UnixWare), SPARC (Solaris) MIPS (Irix
294 5), and HPPA ELF targets.
295
296 * The -( (--start-group) and -) (--end-group) options have been added to
297 support searching a group of archives as though they were a single archive.
298 This can also be used in a linker script, as GROUP ( files ).
299
300 * When a file is named on the command line, and the linker does not recognize
301 it as an object file, the linker will now treat the file as a linker script
302 file. A linker script named in this way augments, but does not replace, the
303 default linker script.
304
305 * The -warn-once option was added. It causes the linker to only warn once per
306 undefined symbol, rather than once per reference.
307
308 * The COFF backend has been converted to the new linker code. As with ELF, to
309 use the new linker, each particular target requires a relocation function. So
310 far, this function has been written for the i386, m68k, a29k and SH targets.
311
312 * The -V flag was made a synonym for -v, for SVR4 compatibility. The old -V
313 behaviour is available via --verbose.
314
315 Changes in version 2.4:
316
317 * New linker code, by Steve Chamberlain and Ian Taylor. For a.out and ecoff
318 formats (so far), this should result in considerable savings in time
319 and memory used while linking; slightly poorer performance than
320 before for formats not converted yet.
321
322 * Command-line parsing is no longer done with flex. This means
323 oddball characters in filenames won't get treated as argument
324 separators.
325
326 * HP-PA ELF support, by Jeff Law. (No SOM support yet.)
327
328 * Mach i386 support, by David Mackenzie.
329
330 * Irix 4 shared libraries are now supported (Irix 5 uses ELF, and ELF shared
331 libraries are not yet supported).
332
333 * COFF shared libraries (as on SCO) should work as well.
334
335 * The linker is disabled for Solaris. (Actually, it was in 2.3 also, I just
336 forgot to note it.) Some of their C library routines don't work when
337 statically linked, and the GNU linker doesn't support dynamic linking yet.
338
339 Changes in version 2.3:
340
341 * Weak symbols are now supported.
342
343 * ELF support has been added. The linker has been bootstrapped on
344 UnixWare and Solaris.
345
346 * Alpha OSF/1 support has been added (non dynamic linking only).
347
348 Changes in version 2.2:
349
350 * The `bfd' library has been updated to reduce a.out-format string
351 table size. The effect of this is that files linked from many input
352 files with duplicate symbols (`-g' debugging records, or identical
353 static symbols) should be much smaller.
354
355 Changes in version 2.1:
356
357 * The ld -ySYMBOL flag (to trace references to SYMBOL) is now implemented.
358
359 * There is now support for writing ECOFF files, so ld and the
360 other utilities should work on Risc/Ultrix and Irix.
361
362 \f
363 Local variables:
364 fill-column: 79
365 End:
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