1-*- text -*- 2 3Changes in 2.27: 4 5* Add a configure option --enable-relro to decide whether -z relro should 6 be enabled in ELF linker by default. Default to yes for all Linux 7 targets except FRV, HPPA, IA64 and MIPS. 8 9* Support for -z noreloc-overflow in the x86-64 ELF linker to disable 10 relocation overflow check. 11 12* Add -z common/-z nocommon options for ELF targets to control whether to 13 convert common symbols to the STT_COMMON type during a relocatable link. 14 15* Support for -z nodynamic-undefined-weak in the x86 ELF linker, which 16 avoids dynamic relocations against undefined weak symbols in executable. 17 18* The NOCROSSREFSTO command was added to the linker script language. 19 20* Add --no-apply-dynamic-relocs to the AArch64 linker to do not apply link-time 21 values for dynamic relocations. 22 23Changes in 2.26: 24 25* Add --fix-stm32l4xx-629360 to the ARM linker to enable a link-time 26 workaround for a bug in the bus matrix / memory controller for some of 27 the STM32 Cortex-M4 based products (STM32L4xx) 28 29* Add a configure option --enable-compressed-debug-sections={all,ld} to 30 decide whether DWARF debug sections should be compressed by default. 31 32* Add support for the ARC EM/HS, and ARC600/700 architectures. 33 34* Experimental support for linker garbage collection (--gc-sections) 35 has been enabled for COFF and PE based targets. 36 37* New command line option for ELF targets to compress DWARF debug 38 sections, --compress-debug-sections=[none|zlib|zlib-gnu|zlib-gabi]. 39 40* New command line option, --orphan-handling=[place|warn|error|discard], to 41 adjust how orphan sections are handled. The default is 'place' which gives 42 the current behaviour, 'warn' and 'error' issue a warning or error 43 respectively when orphan sections are found, and 'discard' will discard all 44 orphan sections. 45 46* Add support for LLVM plugin. 47 48* Add --print-memory-usage option to report memory blocks usage. 49 50* Add --require-defined option, it's like --undefined except the new symbol 51 must be defined by the end of the link. 52 53Changes in 2.25: 54 55* PE binaries now once again contain real timestamps by default. To disable 56 the inclusion of a timestamp in a PE binary, use the --no-insert-timestamp 57 command line option. 58 59* Replace support for openrisc and or32 with support for or1k. 60 61* Add support for the --build-id command line option to COFF based targets. 62 63* x86/x86_64 pe-coff now supports the --build-id option. 64 65* Add support for the Andes NDS32. 66 67Changes in 2.24: 68 69* Add LOG2CEIL() builtin function to the linker script language 70 71* Add support for the Texas Instruments MSP430X processor. 72 73* Add support for Altera Nios II. 74 75* Add support for the V850E3V5 architecture. 76 77* Add support for the Imagination Technologies Meta processor. 78 79* --enable-new-dtags no longer generates old dtags in addition to new dtags. 80 81* Remove linker support for MIPS ECOFF targets. 82 83* Add ALIGN_WITH_INPUT to the linker script language to force the alignment of 84 an output section to use the maximum alignment of all its input sections. 85 86Changes in 2.23: 87 88* Enable compressed debug section feature for x86/x86_64 pe-coff. 89 90* Add support for the 64-bit ARM architecture: AArch64. 91 92* Added SORT_NONE to the linker script language to disable section sorting. 93 94* Add a linker-provided symbol when producing ELF output, '__ehdr_start' 95 to point to the ELF file header (and nearby program headers) in the 96 program's memory image. 97 98* Add support for S12X processor. 99 100* Add support for the VLE extension to the PowerPC architecture. 101 102* Add support for the Freescale XGATE architecture. 103 104* Add option -f FILE on AIX (for response file). 105 106* Add support for the Renesas RL78 architecture. 107 108* Add support for the Adapteva EPIPHANY architecture. 109 110Changes in 2.22: 111 112* --copy-dt-needed-entries is no longer enabled by default. Instead 113 --no-copy-dt-needed-entries is the default. 114 115* INPUT_SECTION_FLAGS has been added to the linker script language 116 to allow selection of input sections by section header section flags. 117 118* Add support for the Tilera TILEPro and TILE-Gx architectures. 119 120* Added SORT_BY_INIT_PRIORITY to the linker script language to permit 121 sorting sections by numerical value of the GCC init_priority attribute 122 encoded in the section name. 123 124Changes in 2.21: 125 126* Linker script expression evaluation is somewhat more sane. This may 127 break scripts that depend on quirks of the old expression evaluation. 128 129* Turn off underscoring for x86_64 PE+-COFF targets. For old behavior the 130 option --enable-leading-mingw64-underscores can be used on configure of 131 bfd. 132 133* Add support for the TMS320C6000 (TI C6X) processor family. 134 135* --add-needed renamed to --copy-dt-needed-entries in order to avoid confusion 136 with --as-needed option. 137 138* Extend .def file syntax by '== <ID>' for imports and exports. This allows 139 to alias the import/export table name written in PE image. 140 141* Add --exclude-all-symbols option to PE based linkers. This prevents all 142 symbols from automatically being exported. 143 144* Add support for the Renesas RX processor. 145 146* Add support for alpha-vms target. 147 148Changes in 2.20: 149 150* GNU/Linux targets now support the STB_GNU_UNIQUE symbol binding. This is a 151 GNU extension to the standard set of ELF symbol bindings. The binding will 152 be passed on to the dynamic linker which will make sure that in the entire 153 process there is just one symbol with the given name and type in use. 154 155* PE targets now support a GNU extension to allow the alignment of common 156 common symbols to be specified. This support uses custom options in 157 the .drectve section, which will be disregarded by the native tools. 158 159* PE targets now add primitive support for ELF version scripts; symbols 160 are not versioned, but the local and global symbol visibility directives 161 are respected when filtering symbols in auto-export mode. 162 163* New option --no-export-dynamic to undo the effect of the -E and 164 --export-dynamic options. 165 166* ELF: --warn-alternate-em option to warn if an object has alternate 167 ELF machine code. 168 169* New script function REGION_ALIAS to add alias names to memory regions. 170 171* PE targets no longer make use of the long section names PE extension to 172 the COFF format when generating executable images, by default. The old 173 (slightly non-conformant) behaviour can still be invoked by using the 174 new '--enable-long-section-names' command-line option. It is also enabled 175 automatically in the presence of un-stripped debug information, as GDB 176 needs to be able to find the debug info sections by their full names. 177 178* For GNU/Linux systems the linker will now avoid processing any relocations 179 made against symbols of the STT_GNU_IFUNC type and instead emit them into 180 the resulting binary for processing by the loader. 181 182* --as-needed now links in a dynamic library if it satisfies undefined 183 symbols in regular objects, or in other dynamic libraries. In the 184 latter case the library is not linked if it is found in a DT_NEEDED 185 entry of one of the libraries already linked. 186 187* Add a new command line option, -Ttext-segment ADDR, for ELF targets 188 to set the address of the first byte of the text segment. 189 190* Add support for Sunplus score architecture. 191 192* Add new option --use-nul-prefixed-import-tables to ld for PE targets to 193 allow fallback to old import table generation with null element prefix. 194 195* Windows PE systems now support a new --exclude-modules-for-implib option, 196 allowing users to partition object files and archive members between a DLL 197 and its associated import library as they are generated during linking. 198 199* Add support for Lattice Mico32 (lm32) architecture. 200 201* Add CR16 ELF --embedded-relocs (used to embedded relocations into binaries 202 for Embedded-PIC code) option. 203 204* Add to the PE/PE+ targets the support of two different kinds of 205 pseudo-relocations. They can be selected by the switches 206 --enable-runtime-pseudo-reloc-v1 and --enable-runtime-pseudo-reloc-v2. 207 For the switch --enable-runtime-pseudo-reloc it uses for 32-bit 208 runtime pseudo relocation version one, for 64-bit the version two. 209 210Changes in 2.19: 211 212* Linker scripts support a new INSERT command that makes it easier to 213 augment the default script. 214 215* Linker script input section filespecs may now specify a file within an 216 archive by writing "archive:file". 217 218* The --sort-common switch now has an optional argument which specifies the 219 direction of sorting. 220 221* The M68K linker now supports multiple GOT generation schemes controlled via 222 the --got=<type> command line option. 223 224* The ARM EABI linker will now generate stubs for function calls to symbols 225 that are too far away. The placement of the stubs is controlled by a new 226 linker command line option: --stub-group-size=N. 227 228Changes in 2.18: 229 230* Linker sources now released under version 3 of the GNU General Public 231 License. 232 233* ELF: New --build-id option to generate a unique per-binary identifier 234 embedded in a note section. 235 236* Added support for National Semicondutor CompactRISC (ie CR16) target. 237 238* -l:foo now searches the library path for a filename called foo, 239 without converting it to libfoo.a or libfoo.so. 240 241* Add a new command line option '--default-script=FILE' or '-dT FILE' 242 which specifies a replacement for the built in, default linker 243 script. 244 245* ELF: Add -Bsymbolic-functions, --dynamic-list-cpp-new, which puts C++ 246 operator new and delete on the dynamic list, and --dynamic-list-data, 247 builtin list for --dynamic-list, which puts global data symbols on the 248 dynamic list. 249 250* Add support for x86_64 PE+ target. 251 252* Add support for Score target. 253 254* ELF: Add --dynamic-list option to specify a list of global symbols 255 whose references shouldn't be bound to the definition within the 256 shared library, or a list of symbols which should be added to the 257 symbol table in the executable. 258 259* The default output section LMA has changed for allocatable sections from 260 being equal to VMA, to keeping the difference between LMA and VMA the same as 261 the previous output section in the same region. This is a more useful 262 default when using overlays and other cases where you specify an LMA 263 differing from the VMA for some sections. 264 265* New switch: --print-gc-sections to list any sections removed by garabge 266 collection. 267 268* ARM: Added --vfp11-denorm-fix option to work around an erratum in current 269 VFP11 coprocessors. 270 271Changes in 2.17: 272 273* Support for the Infineon XC16X has been added by KPIT Cummins Infosystems. 274 275* Modify the Linux linker search order to better match ld.so search order. 276 Look for DT_NEEDED libraries in paths specified by ld.so.conf before 277 searching the default directories, rather than vice versa. 278 Use $prefix/etc/ld.so.conf if it exists, otherwise /etc/ld.so.conf. 279 280* PE-COFF: Forward exports from DLL's can now be specified in .def files 281 passed directly to ld. 282 283* Support for the Z80 processor family has been added. 284 285* Add support for the "@<file>" syntax to the command line, so that extra 286 switches can be read from <file>. 287 288Changes in 2.16: 289 290* Support for the R_ARM_V4BX relocation as defined in the ARM AAELF 291 specification has been added via the --fix-v4bx command-line option. 292 293* New linker script construct AS_NEEDED(), which sets the --as-needed flag 294 for input files listed inside of it. 295 296* A new command-line option, --sysroot, can be used to override the 297 default sysroot location. It only applies to toolchains that were 298 configured using --with-sysroot. 299 300* New linker script functions: ORIGIN() and LENGTH() which return information 301 about a specified memory region. 302 303* Port to MAXQ processor contributed by HCL Tech. 304 305* Added SEGMENT_START to the linker script language to permit the user to 306 override the base address for a segment from the command-line. 307 308* ELF: --warn-shared-textrel option to warn if adding a DT_TEXTREL to a shared 309 object. 310 311* Added SORT_BY_NAME and SORT_BY_ALIGNMENT to the linker script 312 language to permit sorting sections by section name or section 313 maximum alignment. 314 315* Added a new linker command line switch, --sort-section name|alignment, 316 to sort sections by section name or maximum alignment. 317 318* ELF: --add-needed/--no-add-needed options to control if a DT_NEEDED tag 319 should be added when a shared library comes from DT_NEEDED tags. 320 321* Support for the crx-elf target added. 322 323* Support for the sh-symbianelf target added. 324 325* A new linker command line switch has been added which allows the hash table 326 size to be set to a suitable prime value near to its argument. This switch 327 is --hash-size=<NUMBER>. Also if the switch --reduce-memory-overheads is 328 used, and --hash-size has not been used, then the default value will be set 329 to 1021. 330 331* Linker map files are now generated with an O(N) algorithm for finding symbols 332 that are defined in each section. This uses about 40% more memory for 333 symbols than the old O(N^2) algorithm. You can use the new 334 --reduce-memory-overheads option to select the old algorithm; this option 335 might also be used in the future to select similar tradeoffs. 336 337Changes in 2.15: 338 339* ELF: --as-needed/--no-as-needed options to control if a DT_NEEDED tag should 340 be added only when a shared library is referenced. 341 342* PE: --large-address-aware option to indicate executables support virtual 343 addresses greater than 2 gigabytes. 344 345* DWARF 2 support for i386pe added. 346 347* The linker script operator DEFINED() will now yield 1 only for a symbol that 348 is defined before the statement where DEFINED is used. 349 350* The MIPS --embedded-relocs (used to embed relocations into binaries for 351 Embedded-PIC code) is deprecated and will be removed in a future release. 352 353* cr16c support added by NSC. 354 355* m32r Linux (ELF) support added by Renesas. 356 357* Improved linker's handling of unresolved symbols. The switch 358 --unresolved-symbols=<method> has been added to tell the linker when it 359 should report them and the switch --warn-unresolved-symbols has been added to 360 make reports be issued as warning messages rather than errors. 361 362Changes in 2.14: 363 364* Added support for Xtensa architecture. 365 366* Added --with-sysroot configure switch to specify a target system root, for 367 linking against a target filesystem image. 368 369* Added --accept-unknown-linker-format to restore old linker behaviour (pre 370 2.14) of silently accepting and linking in any files in an unknown binary 371 file format. 372 373* Added --no-omagic to undo the effects of the -N option. 374 375* Support for Texas Instruments TMS320C4x and TMS320C3x series of 376 DSP's contributed by Michael Hayes and Svein E. Seldal. 377 378* Added --with-lib-path configure switch to specify default value for 379 LIB_PATH. 380 381* ARM port to QNX operating system added by Graeme Peterson. 382 383* IP2K support added by Denis Chertykov. 384 385Changes in 2.13: 386 387* Support for the Fujitsu FRV architecture added by Red Hat. Models for FR400 388 and FR500 included. 389 390Changes in version 2.13: 391 392* DEC VAX ELF support, by Matt Thomas. 393 394Changes in version 2.12: 395 396* Support for Don Knuth's MMIX, by Hans-Peter Nilsson. 397 398* Support for the OpenRISC 32-bit embedded processor by OpenCores. 399 400* Support for -z nocopyreloc in the x86 ELF linker, which disables 401 production of copy relocs. Warning: using this option may result in 402 non-sharable applications. 403 404* Support for -z combreloc in the ELF linker, which puts dynamic 405 relocations against the same symbol together, so that dynamic linker 406 can use an one-entry symbol lookup cache. 407 408* Support for ELF SHF_MERGE section merging, by Jakub Jelinek. 409 410Changes in version 2.11: 411 412* Support for AMD x86-64 architecture, by Jan Hubicka, SuSE Labs. 413 414* Support added for eliminating duplicate DWARF2 debug information by 415 having the compiler generate the information in sections called 416 .gnu.linkonce.wi.XXXX where XXXX is a checksum for the contents. The 417 linker then merges these sections together into the normal .debug_info 418 section. 419 420* The native ELF linker now searches the directories in DT_RUNPATH or 421 DT_RPATH of a shared library for shared libraries needed by it. 422 423* TI C54x support, by Timothy Wall. 424 425* Added command line switch --section-start to set the start address of any 426 specified section. 427 428* Added ability to emit full relocation information in linked executables, 429 enabled by --emit-relocs. Some post-linkage optimization tools need 430 this information in order to be able to correctly identify and perform 431 symbol relative addressing in the event of changes in section contents 432 (instructions being added or deleted, extending data sections, etc.) 433 434* Support for i860, by Jason Eckhardt (preliminary, alpha quality). 435 436* Support for CRIS (Axis Communications ETRAX series). 437 438* Support for PDP-11 and 2.11BSD a.out format, by Lars Brinkhoff. 439 440Changes in version 2.10: 441 442* Added AT> to the linker script language to allow load-time allocation of 443 sections into regions. 444 445* Added garbage collection of unused sections, enabled by --gc-sections. 446 It does require a bit of backend support; currently implemented are 447 arm-elf, avr-elf, d10v-elf, fr30-elf, i386-elf, m32r-elf, m68k-elf, 448 mcore-elf, mips-elf, mn10300-elf, ppc-elf, sh-elf, sparc-elf, and v850-elf. 449 Others will ignore the option. 450 451* Added SORT to the linker script language to permit sorting sections by file 452 name or section name. 453 454* Added EXTERN to the linker script language as an equivalent to the -u 455 command-line option. 456 457* Added ASSERT to the linker script language. 458 459* Added EXCLUDE_FILE to the linker script language for further control over 460 wildcard file names. 461 462* Added -O option to optimize linker output (as of this writing, this only 463 affects ELF shared library generation). 464 465* The -e option now accepts a number as well as a symbol name. 466 467* Added --no-undefined option to disallow undefined symbols when creating a 468 shared library. 469 470* The linker now issues a warning, not an error, for an undefined symbol when 471 using -Bsymbolic; use the new --no-undefined option to get the old 472 behaviour. 473 474* Added --demangle and --no-demangle options. 475 476Changes in version 2.9: 477 478* Added SQUAD to the linker script language. 479 480* New option --no-warn-mismatch. 481 482* The MEMORY command now parses the attributes to determine where sections that 483 are not placed in a specific memory region are placed. 484 485Changes in version 2.8: 486 487* Linker scripts may now contain shell wildcard characters for file and section 488 names. 489 490* The linker now supports symbol versions in ELF. 491 492* The NOCROSSREFS command was added to the linker script language. 493 494* The LOADADDR expression was added to the linker script language. 495 496* MAX and MIN functions were added to the linker script language. 497 498* The OVERLAY construct was added to the linker script language. 499 500* New option --warn-section-align to warn when the address of an output section 501 changes due to alignment of an input section. 502 503* New options --filter/-F and --auxiliary/-f. 504 505Changes in version 2.7: 506 507* New option --cref to print out a cross reference table. 508 509* New option --wrap SYMBOL. 510 511* New option --no-whole-archive, to turn off the effect of --whole-archive. 512 513* Input sections assigned to the output section /DISCARD/ in the linker script 514 are not included in the output file. 515 516* The SunOS and ELF linkers now merge stabs debugging information which uses 517 the N_BINCL and N_EINCL stab types. This reduces the amount of debugging 518 information generated. 519 520Changes in version 2.6: 521 522* When an ELF section name is representable as a C identifier (this is not true 523of most ELF section names), the linker will automatically define symbols 524__start_SECNAME and __stop_SECNAME, where SECNAME is the section name, at the 525beginning and the end of the section. This is used by glibc. 526 527 Addendum: Current versions of the linker (at least for version 2.18 onwards 528and possibly much earlier as well) place two restrictions on this feature: The 529symbols are only implemented for orphaned sections, not for explicitly placed 530sections and they are PROVIDEd rather than being defined. 531 532* When an ELF section named .gnu.warning is encountered in an input file, the 533contents of the section are displayed as an error message, and the section is 534not copied into the output file. This is used by glibc. 535 536* When an ELF section named .gnu.warning.SYMBOL is encountered in an input 537file, and the symbol SYMBOL is referenced by some object file, the contents of 538the section are displayed as an error message. The section is not copied into 539the output file, unless doing a relocatable or shared link. This is used by 540glibc. 541 542* New options -split-by-reloc and -split-by-file. 543 544* The linker now supports linking PIC compiled code on SPARC SunOS. It can 545also create SPARC SunOS shared libraries, and, like the native SunOS linker, 546will do so whenever there is an undefined symbol in the link and neither the -e 547nor the -r option was used. 548 549* The -rpath option may be used on SunOS to set the list of directories to be 550searched at run time. This overrides the default of building the list from the 551-L options. 552 553* The COFF linker now combines debugging information for structs, unions, and 554enums, so that even if the same type is defined in multiple input files it will 555only be defined once in the output file. The --traditional-format switch will 556prevent this optimization. 557 558Changes in version 2.5: 559 560* The linker now supports linking against SunOS shared libraries. It still can 561not link SunOS PIC (Position Independent Code) files, so it can not be used to 562generate shared libraries. 563 564* The linker now supports linking against ELF shared libraries for the i386 565(UnixWare) and SPARC (Solaris). It can also link ELF PIC files, and can be 566used to generate shared libraries. Shared library generation is not well 567tested; please report any problems encountered. The linker is now enabled for 568Solaris again. 569 570* Eric Youngdale has contributed Linux support code, including linking against 571Linux a.out shared libraries. The linker produces Linux QMAGIC binaries. 572 573* The ELF backend has been converted to the new linker code. To use the new 574ELF linker, each particular target requires a relocation function. So far, 575this function has been written for i386 (UnixWare), SPARC (Solaris) MIPS (Irix 5765), and HPPA ELF targets. 577 578* The -( (--start-group) and -) (--end-group) options have been added to 579support searching a group of archives as though they were a single archive. 580This can also be used in a linker script, as GROUP ( files ). 581 582* When a file is named on the command line, and the linker does not recognize 583it as an object file, the linker will now treat the file as a linker script 584file. A linker script named in this way augments, but does not replace, the 585default linker script. 586 587* The -warn-once option was added. It causes the linker to only warn once per 588undefined symbol, rather than once per reference. 589 590* The COFF backend has been converted to the new linker code. As with ELF, to 591use the new linker, each particular target requires a relocation function. So 592far, this function has been written for the i386, m68k, a29k and SH targets. 593 594* The -V flag was made a synonym for -v, for SVR4 compatibility. The old -V 595behaviour is available via --verbose. 596 597Changes in version 2.4: 598 599* New linker code, by Steve Chamberlain and Ian Taylor. For a.out and ecoff 600 formats (so far), this should result in considerable savings in time 601 and memory used while linking; slightly poorer performance than 602 before for formats not converted yet. 603 604* Command-line parsing is no longer done with flex. This means 605 oddball characters in filenames won't get treated as argument 606 separators. 607 608* HP-PA ELF support, by Jeff Law. (No SOM support yet.) 609 610* Mach i386 support, by David Mackenzie. 611 612* Irix 4 shared libraries are now supported (Irix 5 uses ELF, and ELF shared 613 libraries are not yet supported). 614 615* COFF shared libraries (as on SCO) should work as well. 616 617* The linker is disabled for Solaris. (Actually, it was in 2.3 also, I just 618 forgot to note it.) Some of their C library routines don't work when 619 statically linked, and the GNU linker doesn't support dynamic linking yet. 620 621Changes in version 2.3: 622 623* Weak symbols are now supported. 624 625* ELF support has been added. The linker has been bootstrapped on 626 UnixWare and Solaris. 627 628* Alpha OSF/1 support has been added (non dynamic linking only). 629 630Changes in version 2.2: 631 632* The `bfd' library has been updated to reduce a.out-format string 633 table size. The effect of this is that files linked from many input 634 files with duplicate symbols (`-g' debugging records, or identical 635 static symbols) should be much smaller. 636 637Changes in version 2.1: 638 639* The ld -ySYMBOL flag (to trace references to SYMBOL) is now implemented. 640 641* There is now support for writing ECOFF files, so ld and the 642 other utilities should work on Risc/Ultrix and Irix. 643 644 645Copyright (C) 2012-2016 Free Software Foundation, Inc. 646 647Copying and distribution of this file, with or without modification, 648are permitted in any medium without royalty provided the copyright 649notice and this notice are preserved. 650 651Local variables: 652fill-column: 79 653End: 654