1-*- text -*- 2 3Changes in 2.21: 4 5 6* Linker script expression evaluation is somewhat more sane. This may 7 break scripts that depend on quirks of the old expression evaluation. 8 9* Turn off underscoring for x86_64 PE+-COFF targets. For old behavior the 10 option --enable-leading-mingw64-underscores can be used on configure of 11 bfd. 12 13* Add support for the TMS320C6000 (TI C6X) processor family. 14 15* --add-needed renamed to --copy-dt-needed-entries in order to avoid confusion 16 with --as-needed option. 17 18* Extend .def file syntax by '== <ID>' for imports and exports. This allows 19 to alias the import/export table name written in PE image. 20 21* Add --exlcude-all-symbols option to PE based linkers. This prevents all 22 symbols from automatically being exported. 23 24* Add support for the Renesas RX processor. 25 26* Add support for alpha-vms target. 27 28Changes in 2.20: 29 30* GNU/Linux targets now support the STB_GNU_UNIQUE symbol binding. This is a 31 GNU extension to the standard set of ELF symbol bindings. The binding will 32 be passed on to the dynamic linker which will make sure that in the entire 33 process there is just one symbol with the given name and type in use. 34 35* PE targets now support a GNU extension to allow the alignment of common 36 common symbols to be specified. This support uses custom options in 37 the .drectve section, which will be disregarded by the native tools. 38 39* PE targets now add primitive support for ELF version scripts; symbols 40 are not versioned, but the local and global symbol visibility directives 41 are respected when filtering symbols in auto-export mode. 42 43* New option --no-export-dynamic to undo the effect of the -E and 44 --export-dynamic options. 45 46* ELF: --warn-alternate-em option to warn if an object has alternate 47 ELF machine code. 48 49* New script function REGION_ALIAS to add alias names to memory regions. 50 51* PE targets no longer make use of the long section names PE extension to 52 the COFF format when generating executable images, by default. The old 53 (slightly non-conformant) behaviour can still be invoked by using the 54 new '--enable-long-section-names' command-line option. It is also enabled 55 automatically in the presence of un-stripped debug information, as GDB 56 needs to be able to find the debug info sections by their full names. 57 58* For GNU/Linux systems the linker will now avoid processing any relocations 59 made against symbols of the STT_GNU_IFUNC type and instead emit them into 60 the resulting binary for processing by the loader. 61 62* --as-needed now links in a dynamic library if it satisfies undefined 63 symbols in regular objects, or in other dynamic libraries. In the 64 latter case the library is not linked if it is found in a DT_NEEDED 65 entry of one of the libraries already linked. 66 67* Add a new command line option, -Ttext-segment ADDR, for ELF targets 68 to set the address of the first byte of the text segment. 69 70* Add support for Sunplus score architecture. 71 72* Add new option --use-nul-prefixed-import-tables to ld for PE targets to 73 allow fallback to old import table generation with null element prefix. 74 75* Windows PE systems now support a new --exclude-modules-for-implib option, 76 allowing users to partition object files and archive members between a DLL 77 and its associated import library as they are generated during linking. 78 79* Add support for Lattice Mico32 (lm32) architecture. 80 81* Add CR16 ELF --embedded-relocs (used to embedded relocations into binaries 82 for Embedded-PIC code) option. 83 84* Add to the PE/PE+ targets the support of two different kinds of 85 pseudo-relocations. They can be selected by the switches 86 --enable-runtime-pseudo-reloc-v1 and --enable-runtime-pseudo-reloc-v2. 87 For the switch --enable-runtime-pseudo-reloc it uses for 32-bit 88 runtime pseudo relocation version one, for 64-bit the version two. 89 90Changes in 2.19: 91 92* Linker scripts support a new INSERT command that makes it easier to 93 augment the default script. 94 95* Linker script input section filespecs may now specify a file within an 96 archive by writing "archive:file". 97 98* The --sort-common switch now has an optional argument which specifies the 99 direction of sorting. 100 101* The M68K linker now supports multiple GOT generation schemes controlled via 102 the --got=<type> command line option. 103 104* The ARM EABI linker will now generate stubs for function calls to symbols 105 that are too far away. The placement of the stubs is controlled by a new 106 linker command line option: --stub-group-size=N. 107 108Changes in 2.18: 109 110* Linker sources now released under version 3 of the GNU General Public 111 License. 112 113* ELF: New --build-id option to generate a unique per-binary identifier 114 embedded in a note section. 115 116* Added support for National Semicondutor CompactRISC (ie CR16) target. 117 118* -l:foo now searches the library path for a filename called foo, 119 without converting it to libfoo.a or libfoo.so. 120 121* Add a new command line option '--default-script=FILE' or '-dT FILE' 122 which specifies a replacement for the built in, default linker 123 script. 124 125* ELF: Add -Bsymbolic-functions, --dynamic-list-cpp-new, which puts C++ 126 operator new and delete on the dynamic list, and --dynamic-list-data, 127 builtin list for --dynamic-list, which puts global data symbols on the 128 dynamic list. 129 130* Add support for x86_64 PE+ target. 131 132* Add support for Score target. 133 134* ELF: Add --dynamic-list option to specify a list of global symbols 135 whose references shouldn't be bound to the definition within the 136 shared library, or a list of symbols which should be added to the 137 symbol table in the executable. 138 139* The default output section LMA has changed for allocatable sections from 140 being equal to VMA, to keeping the difference between LMA and VMA the same as 141 the previous output section in the same region. This is a more useful 142 default when using overlays and other cases where you specify an LMA 143 differing from the VMA for some sections. 144 145* New switch: --print-gc-sections to list any sections removed by garabge 146 collection. 147 148* ARM: Added --vfp11-denorm-fix option to work around an erratum in current 149 VFP11 coprocessors. 150 151Changes in 2.17: 152 153* Support for the Infineon XC16X has been added by KPIT Cummins Infosystems. 154 155* Modify the Linux linker search order to better match ld.so search order. 156 Look for DT_NEEDED libraries in paths specified by ld.so.conf before 157 searching the default directories, rather than vice versa. 158 Use $prefix/etc/ld.so.conf if it exists, otherwise /etc/ld.so.conf. 159 160* PE-COFF: Forward exports from DLL's can now be specified in .def files 161 passed directly to ld. 162 163* Support for the Z80 processor family has been added. 164 165* Add support for the "@<file>" syntax to the command line, so that extra 166 switches can be read from <file>. 167 168Changes in 2.16: 169 170* Support for the R_ARM_V4BX relocation as defined in the ARM AAELF 171 specification has been added via the --fix-v4bx command-line option. 172 173* New linker script construct AS_NEEDED(), which sets the --as-needed flag 174 for input files listed inside of it. 175 176* A new command-line option, --sysroot, can be used to override the 177 default sysroot location. It only applies to toolchains that were 178 configured using --with-sysroot. 179 180* New linker script functions: ORIGIN() and LENGTH() which return information 181 about a specified memory region. 182 183* Port to MAXQ processor contributed by HCL Tech. 184 185* Added SEGMENT_START to the linker script language to permit the user to 186 override the base address for a segment from the command-line. 187 188* ELF: --warn-shared-textrel option to warn if adding a DT_TEXTREL to a shared 189 object. 190 191* Added SORT_BY_NAME and SORT_BY_ALIGNMENT to the linker script 192 language to permit sorting sections by section name or section 193 maximum alignment. 194 195* Added a new linker command line switch, --sort-section name|alignment, 196 to sort sections by section name or maximum alignment. 197 198* ELF: --add-needed/--no-add-needed options to control if a DT_NEEDED tag 199 should be added when a shared library comes from DT_NEEDED tags. 200 201* Support for the crx-elf target added. 202 203* Support for the sh-symbianelf target added. 204 205* A new linker command line switch has been added which allows the hash table 206 size to be set to a suitable prime value near to its argument. This switch 207 is --hash-size=<NUMBER>. Also if the switch --reduce-memory-overheads is 208 used, and --hash-size has not been used, then the default value will be set 209 to 1021. 210 211* Linker map files are now generated with an O(N) algorithm for finding symbols 212 that are defined in each section. This uses about 40% more memory for 213 symbols than the old O(N^2) algorithm. You can use the new 214 --reduce-memory-overheads option to select the old algorithm; this option 215 might also be used in the future to select similar tradeoffs. 216 217Changes in 2.15: 218 219* ELF: --as-needed/--no-as-needed options to control if a DT_NEEDED tag should 220 be added only when a shared library is referenced. 221 222* PE: --large-address-aware option to indicate executables support virtual 223 addresses greater than 2 gigabytes. 224 225* DWARF 2 support for i386pe added. 226 227* The linker script operator DEFINED() will now yield 1 only for a symbol that 228 is defined before the statement where DEFINED is used. 229 230* The MIPS --embedded-relocs (used to embed relocations into binaries for 231 Embedded-PIC code) is deprecated and will be removed in a future release. 232 233* cr16c support added by NSC. 234 235* m32r Linux (ELF) support added by Renesas. 236 237* Improved linker's handling of unresolved symbols. The switch 238 --unresolved-symbols=<method> has been added to tell the linker when it 239 should report them and the switch --warn-unresolved-symbols has been added to 240 make reports be issued as warning messages rather than errors. 241 242Changes in 2.14: 243 244* Added support for Xtensa architecture. 245 246* Added --with-sysroot configure switch to specify a target system root, for 247 linking against a target filesystem image. 248 249* Added --accept-unknown-linker-format to restore old linker behaviour (pre 250 2.14) of silently accepting and linking in any files in an unknown binary 251 file format. 252 253* Added --no-omagic to undo the effects of the -N option. 254 255* Support for Texas Instruments TMS320C4x and TMS320C3x series of 256 DSP's contributed by Michael Hayes and Svein E. Seldal. 257 258* Added --with-lib-path configure switch to specify default value for 259 LIB_PATH. 260 261* ARM port to QNX operating system added by Graeme Peterson. 262 263* IP2K support added by Denis Chertykov. 264 265Changes in 2.13: 266 267* Support for the Fujitsu FRV architecture added by Red Hat. Models for FR400 268 and FR500 included. 269 270Changes in version 2.13: 271 272* DEC VAX ELF support, by Matt Thomas. 273 274Changes in version 2.12: 275 276* Support for Don Knuth's MMIX, by Hans-Peter Nilsson. 277 278* Support for the OpenRISC 32-bit embedded processor by OpenCores. 279 280* Support for -z nocopyreloc in the x86 ELF linker, which disables 281 production of copy relocs. Warning: using this option may result in 282 non-sharable applications. 283 284* Support for -z combreloc in the ELF linker, which puts dynamic 285 relocations against the same symbol together, so that dynamic linker 286 can use an one-entry symbol lookup cache. 287 288* Support for ELF SHF_MERGE section merging, by Jakub Jelinek. 289 290Changes in version 2.11: 291 292* Support for AMD x86-64 architecture, by Jan Hubicka, SuSE Labs. 293 294* Support added for eliminating duplicate DWARF2 debug information by 295 having the compiler generate the information in sections called 296 .gnu.linkonce.wi.XXXX where XXXX is a checksum for the contents. The 297 linker then merges these sections together into the normal .debug_info 298 section. 299 300* The native ELF linker now searches the directories in DT_RUNPATH or 301 DT_RPATH of a shared library for shared libraries needed by it. 302 303* TI C54x support, by Timothy Wall. 304 305* Added command line switch --section-start to set the start address of any 306 specified section. 307 308* Added ability to emit full relocation information in linked executables, 309 enabled by --emit-relocs. Some post-linkage optimization tools need 310 this information in order to be able to correctly identify and perform 311 symbol relative addressing in the event of changes in section contents 312 (instructions being added or deleted, extending data sections, etc.) 313 314* Support for i860, by Jason Eckhardt (preliminary, alpha quality). 315 316* Support for CRIS (Axis Communications ETRAX series). 317 318* Support for PDP-11 and 2.11BSD a.out format, by Lars Brinkhoff. 319 320Changes in version 2.10: 321 322* Added AT> to the linker script language to allow load-time allocation of 323 sections into regions. 324 325* Added garbage collection of unused sections, enabled by --gc-sections. 326 It does require a bit of backend support; currently implemented are 327 arm-elf, avr-elf, d10v-elf, fr30-elf, i386-elf, m32r-elf, m68k-elf, 328 mcore-elf, mips-elf, mn10300-elf, ppc-elf, sh-elf, sparc-elf, and v850-elf. 329 Others will ignore the option. 330 331* Added SORT to the linker script language to permit sorting sections by file 332 name or section name. 333 334* Added EXTERN to the linker script language as an equivalent to the -u 335 command-line option. 336 337* Added ASSERT to the linker script language. 338 339* Added EXCLUDE_FILE to the linker script language for further control over 340 wildcard file names. 341 342* Added -O option to optimize linker output (as of this writing, this only 343 affects ELF shared library generation). 344 345* The -e option now accepts a number as well as a symbol name. 346 347* Added --no-undefined option to disallow undefined symbols when creating a 348 shared library. 349 350* The linker now issues a warning, not an error, for an undefined symbol when 351 using -Bsymbolic; use the new --no-undefined option to get the old 352 behaviour. 353 354* Added --demangle and --no-demangle options. 355 356Changes in version 2.9: 357 358* Added SQUAD to the linker script language. 359 360* New option --no-warn-mismatch. 361 362* The MEMORY command now parses the attributes to determine where sections that 363 are not placed in a specific memory region are placed. 364 365Changes in version 2.8: 366 367* Linker scripts may now contain shell wildcard characters for file and section 368 names. 369 370* The linker now supports symbol versions in ELF. 371 372* The NOCROSSREFS command was added to the linker script language. 373 374* The LOADADDR expression was added to the linker script language. 375 376* MAX and MIN functions were added to the linker script language. 377 378* The OVERLAY construct was added to the linker script language. 379 380* New option --warn-section-align to warn when the address of an output section 381 changes due to alignment of an input section. 382 383* New options --filter/-F and --auxiliary/-f. 384 385Changes in version 2.7: 386 387* New option --cref to print out a cross reference table. 388 389* New option --wrap SYMBOL. 390 391* New option --no-whole-archive, to turn off the effect of --whole-archive. 392 393* Input sections assigned to the output section /DISCARD/ in the linker script 394 are not included in the output file. 395 396* The SunOS and ELF linkers now merge stabs debugging information which uses 397 the N_BINCL and N_EINCL stab types. This reduces the amount of debugging 398 information generated. 399 400Changes in version 2.6: 401 402* When an ELF section name is representable as a C identifier (this is not true 403of most ELF section names), the linker will automatically define symbols 404__start_SECNAME and __stop_SECNAME, where SECNAME is the section name, at the 405beginning and the end of the section. This is used by glibc. 406 407 Addendum: Current versions of the linker (at least for version 2.18 onwards 408and possibly much earlier as well) place two restrictions on this feature: The 409symbols are only implemented for orphaned sections, not for explicitly placed 410sections and they are PROVIDEd rather than being defined. 411 412* When an ELF section named .gnu.warning is encountered in an input file, the 413contents of the section are displayed as an error message, and the section is 414not copied into the output file. This is used by glibc. 415 416* When an ELF section named .gnu.warning.SYMBOL is encountered in an input 417file, and the symbol SYMBOL is referenced by some object file, the contents of 418the section are displayed as an error message. The section is not copied into 419the output file, unless doing a relocatable or shared link. This is used by 420glibc. 421 422* New options -split-by-reloc and -split-by-file. 423 424* The linker now supports linking PIC compiled code on SPARC SunOS. It can 425also create SPARC SunOS shared libraries, and, like the native SunOS linker, 426will do so whenever there is an undefined symbol in the link and neither the -e 427nor the -r option was used. 428 429* The -rpath option may be used on SunOS to set the list of directories to be 430searched at run time. This overrides the default of building the list from the 431-L options. 432 433* The COFF linker now combines debugging information for structs, unions, and 434enums, so that even if the same type is defined in multiple input files it will 435only be defined once in the output file. The --traditional-format switch will 436prevent this optimization. 437 438Changes in version 2.5: 439 440* The linker now supports linking against SunOS shared libraries. It still can 441not link SunOS PIC (Position Independent Code) files, so it can not be used to 442generate shared libraries. 443 444* The linker now supports linking against ELF shared libraries for the i386 445(UnixWare) and SPARC (Solaris). It can also link ELF PIC files, and can be 446used to generate shared libraries. Shared library generation is not well 447tested; please report any problems encountered. The linker is now enabled for 448Solaris again. 449 450* Eric Youngdale has contributed Linux support code, including linking against 451Linux a.out shared libraries. The linker produces Linux QMAGIC binaries. 452 453* The ELF backend has been converted to the new linker code. To use the new 454ELF linker, each particular target requires a relocation function. So far, 455this function has been written for i386 (UnixWare), SPARC (Solaris) MIPS (Irix 4565), and HPPA ELF targets. 457 458* The -( (--start-group) and -) (--end-group) options have been added to 459support searching a group of archives as though they were a single archive. 460This can also be used in a linker script, as GROUP ( files ). 461 462* When a file is named on the command line, and the linker does not recognize 463it as an object file, the linker will now treat the file as a linker script 464file. A linker script named in this way augments, but does not replace, the 465default linker script. 466 467* The -warn-once option was added. It causes the linker to only warn once per 468undefined symbol, rather than once per reference. 469 470* The COFF backend has been converted to the new linker code. As with ELF, to 471use the new linker, each particular target requires a relocation function. So 472far, this function has been written for the i386, m68k, a29k and SH targets. 473 474* The -V flag was made a synonym for -v, for SVR4 compatibility. The old -V 475behaviour is available via --verbose. 476 477Changes in version 2.4: 478 479* New linker code, by Steve Chamberlain and Ian Taylor. For a.out and ecoff 480 formats (so far), this should result in considerable savings in time 481 and memory used while linking; slightly poorer performance than 482 before for formats not converted yet. 483 484* Command-line parsing is no longer done with flex. This means 485 oddball characters in filenames won't get treated as argument 486 separators. 487 488* HP-PA ELF support, by Jeff Law. (No SOM support yet.) 489 490* Mach i386 support, by David Mackenzie. 491 492* Irix 4 shared libraries are now supported (Irix 5 uses ELF, and ELF shared 493 libraries are not yet supported). 494 495* COFF shared libraries (as on SCO) should work as well. 496 497* The linker is disabled for Solaris. (Actually, it was in 2.3 also, I just 498 forgot to note it.) Some of their C library routines don't work when 499 statically linked, and the GNU linker doesn't support dynamic linking yet. 500 501Changes in version 2.3: 502 503* Weak symbols are now supported. 504 505* ELF support has been added. The linker has been bootstrapped on 506 UnixWare and Solaris. 507 508* Alpha OSF/1 support has been added (non dynamic linking only). 509 510Changes in version 2.2: 511 512* The `bfd' library has been updated to reduce a.out-format string 513 table size. The effect of this is that files linked from many input 514 files with duplicate symbols (`-g' debugging records, or identical 515 static symbols) should be much smaller. 516 517Changes in version 2.1: 518 519* The ld -ySYMBOL flag (to trace references to SYMBOL) is now implemented. 520 521* There is now support for writing ECOFF files, so ld and the 522 other utilities should work on Risc/Ultrix and Irix. 523 524 525Local variables: 526fill-column: 79 527End: 528