1-*- text -*- 2 3Changes in 2.28: 4 5* The EXCLUDE_FILE linker script construct can now be applied outside of the 6 section list in order for the exclusions to apply over all input sections in 7 the list. 8 9* Add support for the RISC-V architecture. 10 11* The command line option --no-eh-frame-hdr can now be used in ELF based 12 linkers to disable the automatic generation of .eh_frame_hdr sections. 13 14* Add --in-implib=<infile> to the ARM linker to enable specifying a set of 15 Secure Gateway veneers that must exist in the output import library specified 16 by --out-implib=<outfile> and the address they must have. As such, 17 --in-implib is only supported in combination with --cmse-implib. 18 19* Extended the --out-implib=<file> option, previously restricted to x86 PE 20 targets, to any ELF based target. This allows the generation of an import 21 library for an ELF executable, which can then be used by another application 22 to link against the executable. 23 24Changes in 2.27: 25 26* Add a configure option --enable-relro to decide whether -z relro should 27 be enabled in ELF linker by default. Default to yes for all Linux 28 targets except FRV, HPPA, IA64 and MIPS. 29 30* Support for -z noreloc-overflow in the x86-64 ELF linker to disable 31 relocation overflow check. 32 33* Add -z common/-z nocommon options for ELF targets to control whether to 34 convert common symbols to the STT_COMMON type during a relocatable link. 35 36* Support for -z nodynamic-undefined-weak in the x86 ELF linker, which 37 avoids dynamic relocations against undefined weak symbols in executable. 38 39* The NOCROSSREFSTO command was added to the linker script language. 40 41* Add --no-apply-dynamic-relocs to the AArch64 linker to do not apply link-time 42 values for dynamic relocations. 43 44Changes in 2.26: 45 46* Add --fix-stm32l4xx-629360 to the ARM linker to enable a link-time 47 workaround for a bug in the bus matrix / memory controller for some of 48 the STM32 Cortex-M4 based products (STM32L4xx) 49 50* Add a configure option --enable-compressed-debug-sections={all,ld} to 51 decide whether DWARF debug sections should be compressed by default. 52 53* Add support for the ARC EM/HS, and ARC600/700 architectures. 54 55* Experimental support for linker garbage collection (--gc-sections) 56 has been enabled for COFF and PE based targets. 57 58* New command line option for ELF targets to compress DWARF debug 59 sections, --compress-debug-sections=[none|zlib|zlib-gnu|zlib-gabi]. 60 61* New command line option, --orphan-handling=[place|warn|error|discard], to 62 adjust how orphan sections are handled. The default is 'place' which gives 63 the current behaviour, 'warn' and 'error' issue a warning or error 64 respectively when orphan sections are found, and 'discard' will discard all 65 orphan sections. 66 67* Add support for LLVM plugin. 68 69* Add --print-memory-usage option to report memory blocks usage. 70 71* Add --require-defined option, it's like --undefined except the new symbol 72 must be defined by the end of the link. 73 74Changes in 2.25: 75 76* PE binaries now once again contain real timestamps by default. To disable 77 the inclusion of a timestamp in a PE binary, use the --no-insert-timestamp 78 command line option. 79 80* Replace support for openrisc and or32 with support for or1k. 81 82* Add support for the --build-id command line option to COFF based targets. 83 84* x86/x86_64 pe-coff now supports the --build-id option. 85 86* Add support for the Andes NDS32. 87 88Changes in 2.24: 89 90* Add LOG2CEIL() builtin function to the linker script language 91 92* Add support for the Texas Instruments MSP430X processor. 93 94* Add support for Altera Nios II. 95 96* Add support for the V850E3V5 architecture. 97 98* Add support for the Imagination Technologies Meta processor. 99 100* --enable-new-dtags no longer generates old dtags in addition to new dtags. 101 102* Remove linker support for MIPS ECOFF targets. 103 104* Add ALIGN_WITH_INPUT to the linker script language to force the alignment of 105 an output section to use the maximum alignment of all its input sections. 106 107Changes in 2.23: 108 109* Enable compressed debug section feature for x86/x86_64 pe-coff. 110 111* Add support for the 64-bit ARM architecture: AArch64. 112 113* Added SORT_NONE to the linker script language to disable section sorting. 114 115* Add a linker-provided symbol when producing ELF output, '__ehdr_start' 116 to point to the ELF file header (and nearby program headers) in the 117 program's memory image. 118 119* Add support for S12X processor. 120 121* Add support for the VLE extension to the PowerPC architecture. 122 123* Add support for the Freescale XGATE architecture. 124 125* Add option -f FILE on AIX (for response file). 126 127* Add support for the Renesas RL78 architecture. 128 129* Add support for the Adapteva EPIPHANY architecture. 130 131Changes in 2.22: 132 133* --copy-dt-needed-entries is no longer enabled by default. Instead 134 --no-copy-dt-needed-entries is the default. 135 136* INPUT_SECTION_FLAGS has been added to the linker script language 137 to allow selection of input sections by section header section flags. 138 139* Add support for the Tilera TILEPro and TILE-Gx architectures. 140 141* Added SORT_BY_INIT_PRIORITY to the linker script language to permit 142 sorting sections by numerical value of the GCC init_priority attribute 143 encoded in the section name. 144 145Changes in 2.21: 146 147* Linker script expression evaluation is somewhat more sane. This may 148 break scripts that depend on quirks of the old expression evaluation. 149 150* Turn off underscoring for x86_64 PE+-COFF targets. For old behavior the 151 option --enable-leading-mingw64-underscores can be used on configure of 152 bfd. 153 154* Add support for the TMS320C6000 (TI C6X) processor family. 155 156* --add-needed renamed to --copy-dt-needed-entries in order to avoid confusion 157 with --as-needed option. 158 159* Extend .def file syntax by '== <ID>' for imports and exports. This allows 160 to alias the import/export table name written in PE image. 161 162* Add --exclude-all-symbols option to PE based linkers. This prevents all 163 symbols from automatically being exported. 164 165* Add support for the Renesas RX processor. 166 167* Add support for alpha-vms target. 168 169Changes in 2.20: 170 171* GNU/Linux targets now support the STB_GNU_UNIQUE symbol binding. This is a 172 GNU extension to the standard set of ELF symbol bindings. The binding will 173 be passed on to the dynamic linker which will make sure that in the entire 174 process there is just one symbol with the given name and type in use. 175 176* PE targets now support a GNU extension to allow the alignment of common 177 common symbols to be specified. This support uses custom options in 178 the .drectve section, which will be disregarded by the native tools. 179 180* PE targets now add primitive support for ELF version scripts; symbols 181 are not versioned, but the local and global symbol visibility directives 182 are respected when filtering symbols in auto-export mode. 183 184* New option --no-export-dynamic to undo the effect of the -E and 185 --export-dynamic options. 186 187* ELF: --warn-alternate-em option to warn if an object has alternate 188 ELF machine code. 189 190* New script function REGION_ALIAS to add alias names to memory regions. 191 192* PE targets no longer make use of the long section names PE extension to 193 the COFF format when generating executable images, by default. The old 194 (slightly non-conformant) behaviour can still be invoked by using the 195 new '--enable-long-section-names' command-line option. It is also enabled 196 automatically in the presence of un-stripped debug information, as GDB 197 needs to be able to find the debug info sections by their full names. 198 199* For GNU/Linux systems the linker will now avoid processing any relocations 200 made against symbols of the STT_GNU_IFUNC type and instead emit them into 201 the resulting binary for processing by the loader. 202 203* --as-needed now links in a dynamic library if it satisfies undefined 204 symbols in regular objects, or in other dynamic libraries. In the 205 latter case the library is not linked if it is found in a DT_NEEDED 206 entry of one of the libraries already linked. 207 208* Add a new command line option, -Ttext-segment ADDR, for ELF targets 209 to set the address of the first byte of the text segment. 210 211* Add support for Sunplus score architecture. 212 213* Add new option --use-nul-prefixed-import-tables to ld for PE targets to 214 allow fallback to old import table generation with null element prefix. 215 216* Windows PE systems now support a new --exclude-modules-for-implib option, 217 allowing users to partition object files and archive members between a DLL 218 and its associated import library as they are generated during linking. 219 220* Add support for Lattice Mico32 (lm32) architecture. 221 222* Add CR16 ELF --embedded-relocs (used to embedded relocations into binaries 223 for Embedded-PIC code) option. 224 225* Add to the PE/PE+ targets the support of two different kinds of 226 pseudo-relocations. They can be selected by the switches 227 --enable-runtime-pseudo-reloc-v1 and --enable-runtime-pseudo-reloc-v2. 228 For the switch --enable-runtime-pseudo-reloc it uses for 32-bit 229 runtime pseudo relocation version one, for 64-bit the version two. 230 231Changes in 2.19: 232 233* Linker scripts support a new INSERT command that makes it easier to 234 augment the default script. 235 236* Linker script input section filespecs may now specify a file within an 237 archive by writing "archive:file". 238 239* The --sort-common switch now has an optional argument which specifies the 240 direction of sorting. 241 242* The M68K linker now supports multiple GOT generation schemes controlled via 243 the --got=<type> command line option. 244 245* The ARM EABI linker will now generate stubs for function calls to symbols 246 that are too far away. The placement of the stubs is controlled by a new 247 linker command line option: --stub-group-size=N. 248 249Changes in 2.18: 250 251* Linker sources now released under version 3 of the GNU General Public 252 License. 253 254* ELF: New --build-id option to generate a unique per-binary identifier 255 embedded in a note section. 256 257* Added support for National Semicondutor CompactRISC (ie CR16) target. 258 259* -l:foo now searches the library path for a filename called foo, 260 without converting it to libfoo.a or libfoo.so. 261 262* Add a new command line option '--default-script=FILE' or '-dT FILE' 263 which specifies a replacement for the built in, default linker 264 script. 265 266* ELF: Add -Bsymbolic-functions, --dynamic-list-cpp-new, which puts C++ 267 operator new and delete on the dynamic list, and --dynamic-list-data, 268 builtin list for --dynamic-list, which puts global data symbols on the 269 dynamic list. 270 271* Add support for x86_64 PE+ target. 272 273* Add support for Score target. 274 275* ELF: Add --dynamic-list option to specify a list of global symbols 276 whose references shouldn't be bound to the definition within the 277 shared library, or a list of symbols which should be added to the 278 symbol table in the executable. 279 280* The default output section LMA has changed for allocatable sections from 281 being equal to VMA, to keeping the difference between LMA and VMA the same as 282 the previous output section in the same region. This is a more useful 283 default when using overlays and other cases where you specify an LMA 284 differing from the VMA for some sections. 285 286* New switch: --print-gc-sections to list any sections removed by garabge 287 collection. 288 289* ARM: Added --vfp11-denorm-fix option to work around an erratum in current 290 VFP11 coprocessors. 291 292Changes in 2.17: 293 294* Support for the Infineon XC16X has been added by KPIT Cummins Infosystems. 295 296* Modify the Linux linker search order to better match ld.so search order. 297 Look for DT_NEEDED libraries in paths specified by ld.so.conf before 298 searching the default directories, rather than vice versa. 299 Use $prefix/etc/ld.so.conf if it exists, otherwise /etc/ld.so.conf. 300 301* PE-COFF: Forward exports from DLL's can now be specified in .def files 302 passed directly to ld. 303 304* Support for the Z80 processor family has been added. 305 306* Add support for the "@<file>" syntax to the command line, so that extra 307 switches can be read from <file>. 308 309Changes in 2.16: 310 311* Support for the R_ARM_V4BX relocation as defined in the ARM AAELF 312 specification has been added via the --fix-v4bx command-line option. 313 314* New linker script construct AS_NEEDED(), which sets the --as-needed flag 315 for input files listed inside of it. 316 317* A new command-line option, --sysroot, can be used to override the 318 default sysroot location. It only applies to toolchains that were 319 configured using --with-sysroot. 320 321* New linker script functions: ORIGIN() and LENGTH() which return information 322 about a specified memory region. 323 324* Port to MAXQ processor contributed by HCL Tech. 325 326* Added SEGMENT_START to the linker script language to permit the user to 327 override the base address for a segment from the command-line. 328 329* ELF: --warn-shared-textrel option to warn if adding a DT_TEXTREL to a shared 330 object. 331 332* Added SORT_BY_NAME and SORT_BY_ALIGNMENT to the linker script 333 language to permit sorting sections by section name or section 334 maximum alignment. 335 336* Added a new linker command line switch, --sort-section name|alignment, 337 to sort sections by section name or maximum alignment. 338 339* ELF: --add-needed/--no-add-needed options to control if a DT_NEEDED tag 340 should be added when a shared library comes from DT_NEEDED tags. 341 342* Support for the crx-elf target added. 343 344* Support for the sh-symbianelf target added. 345 346* A new linker command line switch has been added which allows the hash table 347 size to be set to a suitable prime value near to its argument. This switch 348 is --hash-size=<NUMBER>. Also if the switch --reduce-memory-overheads is 349 used, and --hash-size has not been used, then the default value will be set 350 to 1021. 351 352* Linker map files are now generated with an O(N) algorithm for finding symbols 353 that are defined in each section. This uses about 40% more memory for 354 symbols than the old O(N^2) algorithm. You can use the new 355 --reduce-memory-overheads option to select the old algorithm; this option 356 might also be used in the future to select similar tradeoffs. 357 358Changes in 2.15: 359 360* ELF: --as-needed/--no-as-needed options to control if a DT_NEEDED tag should 361 be added only when a shared library is referenced. 362 363* PE: --large-address-aware option to indicate executables support virtual 364 addresses greater than 2 gigabytes. 365 366* DWARF 2 support for i386pe added. 367 368* The linker script operator DEFINED() will now yield 1 only for a symbol that 369 is defined before the statement where DEFINED is used. 370 371* The MIPS --embedded-relocs (used to embed relocations into binaries for 372 Embedded-PIC code) is deprecated and will be removed in a future release. 373 374* cr16c support added by NSC. 375 376* m32r Linux (ELF) support added by Renesas. 377 378* Improved linker's handling of unresolved symbols. The switch 379 --unresolved-symbols=<method> has been added to tell the linker when it 380 should report them and the switch --warn-unresolved-symbols has been added to 381 make reports be issued as warning messages rather than errors. 382 383Changes in 2.14: 384 385* Added support for Xtensa architecture. 386 387* Added --with-sysroot configure switch to specify a target system root, for 388 linking against a target filesystem image. 389 390* Added --accept-unknown-linker-format to restore old linker behaviour (pre 391 2.14) of silently accepting and linking in any files in an unknown binary 392 file format. 393 394* Added --no-omagic to undo the effects of the -N option. 395 396* Support for Texas Instruments TMS320C4x and TMS320C3x series of 397 DSP's contributed by Michael Hayes and Svein E. Seldal. 398 399* Added --with-lib-path configure switch to specify default value for 400 LIB_PATH. 401 402* ARM port to QNX operating system added by Graeme Peterson. 403 404* IP2K support added by Denis Chertykov. 405 406Changes in 2.13: 407 408* Support for the Fujitsu FRV architecture added by Red Hat. Models for FR400 409 and FR500 included. 410 411Changes in version 2.13: 412 413* DEC VAX ELF support, by Matt Thomas. 414 415Changes in version 2.12: 416 417* Support for Don Knuth's MMIX, by Hans-Peter Nilsson. 418 419* Support for the OpenRISC 32-bit embedded processor by OpenCores. 420 421* Support for -z nocopyreloc in the x86 ELF linker, which disables 422 production of copy relocs. Warning: using this option may result in 423 non-sharable applications. 424 425* Support for -z combreloc in the ELF linker, which puts dynamic 426 relocations against the same symbol together, so that dynamic linker 427 can use an one-entry symbol lookup cache. 428 429* Support for ELF SHF_MERGE section merging, by Jakub Jelinek. 430 431Changes in version 2.11: 432 433* Support for AMD x86-64 architecture, by Jan Hubicka, SuSE Labs. 434 435* Support added for eliminating duplicate DWARF2 debug information by 436 having the compiler generate the information in sections called 437 .gnu.linkonce.wi.XXXX where XXXX is a checksum for the contents. The 438 linker then merges these sections together into the normal .debug_info 439 section. 440 441* The native ELF linker now searches the directories in DT_RUNPATH or 442 DT_RPATH of a shared library for shared libraries needed by it. 443 444* TI C54x support, by Timothy Wall. 445 446* Added command line switch --section-start to set the start address of any 447 specified section. 448 449* Added ability to emit full relocation information in linked executables, 450 enabled by --emit-relocs. Some post-linkage optimization tools need 451 this information in order to be able to correctly identify and perform 452 symbol relative addressing in the event of changes in section contents 453 (instructions being added or deleted, extending data sections, etc.) 454 455* Support for i860, by Jason Eckhardt (preliminary, alpha quality). 456 457* Support for CRIS (Axis Communications ETRAX series). 458 459* Support for PDP-11 and 2.11BSD a.out format, by Lars Brinkhoff. 460 461Changes in version 2.10: 462 463* Added AT> to the linker script language to allow load-time allocation of 464 sections into regions. 465 466* Added garbage collection of unused sections, enabled by --gc-sections. 467 It does require a bit of backend support; currently implemented are 468 arm-elf, avr-elf, d10v-elf, fr30-elf, i386-elf, m32r-elf, m68k-elf, 469 mcore-elf, mips-elf, mn10300-elf, ppc-elf, sh-elf, sparc-elf, and v850-elf. 470 Others will ignore the option. 471 472* Added SORT to the linker script language to permit sorting sections by file 473 name or section name. 474 475* Added EXTERN to the linker script language as an equivalent to the -u 476 command-line option. 477 478* Added ASSERT to the linker script language. 479 480* Added EXCLUDE_FILE to the linker script language for further control over 481 wildcard file names. 482 483* Added -O option to optimize linker output (as of this writing, this only 484 affects ELF shared library generation). 485 486* The -e option now accepts a number as well as a symbol name. 487 488* Added --no-undefined option to disallow undefined symbols when creating a 489 shared library. 490 491* The linker now issues a warning, not an error, for an undefined symbol when 492 using -Bsymbolic; use the new --no-undefined option to get the old 493 behaviour. 494 495* Added --demangle and --no-demangle options. 496 497Changes in version 2.9: 498 499* Added SQUAD to the linker script language. 500 501* New option --no-warn-mismatch. 502 503* The MEMORY command now parses the attributes to determine where sections that 504 are not placed in a specific memory region are placed. 505 506Changes in version 2.8: 507 508* Linker scripts may now contain shell wildcard characters for file and section 509 names. 510 511* The linker now supports symbol versions in ELF. 512 513* The NOCROSSREFS command was added to the linker script language. 514 515* The LOADADDR expression was added to the linker script language. 516 517* MAX and MIN functions were added to the linker script language. 518 519* The OVERLAY construct was added to the linker script language. 520 521* New option --warn-section-align to warn when the address of an output section 522 changes due to alignment of an input section. 523 524* New options --filter/-F and --auxiliary/-f. 525 526Changes in version 2.7: 527 528* New option --cref to print out a cross reference table. 529 530* New option --wrap SYMBOL. 531 532* New option --no-whole-archive, to turn off the effect of --whole-archive. 533 534* Input sections assigned to the output section /DISCARD/ in the linker script 535 are not included in the output file. 536 537* The SunOS and ELF linkers now merge stabs debugging information which uses 538 the N_BINCL and N_EINCL stab types. This reduces the amount of debugging 539 information generated. 540 541Changes in version 2.6: 542 543* When an ELF section name is representable as a C identifier (this is not true 544of most ELF section names), the linker will automatically define symbols 545__start_SECNAME and __stop_SECNAME, where SECNAME is the section name, at the 546beginning and the end of the section. This is used by glibc. 547 548 Addendum: Current versions of the linker (at least for version 2.18 onwards 549and possibly much earlier as well) place two restrictions on this feature: The 550symbols are only implemented for orphaned sections, not for explicitly placed 551sections and they are PROVIDEd rather than being defined. 552 553* When an ELF section named .gnu.warning is encountered in an input file, the 554contents of the section are displayed as an error message, and the section is 555not copied into the output file. This is used by glibc. 556 557* When an ELF section named .gnu.warning.SYMBOL is encountered in an input 558file, and the symbol SYMBOL is referenced by some object file, the contents of 559the section are displayed as an error message. The section is not copied into 560the output file, unless doing a relocatable or shared link. This is used by 561glibc. 562 563* New options -split-by-reloc and -split-by-file. 564 565* The linker now supports linking PIC compiled code on SPARC SunOS. It can 566also create SPARC SunOS shared libraries, and, like the native SunOS linker, 567will do so whenever there is an undefined symbol in the link and neither the -e 568nor the -r option was used. 569 570* The -rpath option may be used on SunOS to set the list of directories to be 571searched at run time. This overrides the default of building the list from the 572-L options. 573 574* The COFF linker now combines debugging information for structs, unions, and 575enums, so that even if the same type is defined in multiple input files it will 576only be defined once in the output file. The --traditional-format switch will 577prevent this optimization. 578 579Changes in version 2.5: 580 581* The linker now supports linking against SunOS shared libraries. It still can 582not link SunOS PIC (Position Independent Code) files, so it can not be used to 583generate shared libraries. 584 585* The linker now supports linking against ELF shared libraries for the i386 586(UnixWare) and SPARC (Solaris). It can also link ELF PIC files, and can be 587used to generate shared libraries. Shared library generation is not well 588tested; please report any problems encountered. The linker is now enabled for 589Solaris again. 590 591* Eric Youngdale has contributed Linux support code, including linking against 592Linux a.out shared libraries. The linker produces Linux QMAGIC binaries. 593 594* The ELF backend has been converted to the new linker code. To use the new 595ELF linker, each particular target requires a relocation function. So far, 596this function has been written for i386 (UnixWare), SPARC (Solaris) MIPS (Irix 5975), and HPPA ELF targets. 598 599* The -( (--start-group) and -) (--end-group) options have been added to 600support searching a group of archives as though they were a single archive. 601This can also be used in a linker script, as GROUP ( files ). 602 603* When a file is named on the command line, and the linker does not recognize 604it as an object file, the linker will now treat the file as a linker script 605file. A linker script named in this way augments, but does not replace, the 606default linker script. 607 608* The -warn-once option was added. It causes the linker to only warn once per 609undefined symbol, rather than once per reference. 610 611* The COFF backend has been converted to the new linker code. As with ELF, to 612use the new linker, each particular target requires a relocation function. So 613far, this function has been written for the i386, m68k, a29k and SH targets. 614 615* The -V flag was made a synonym for -v, for SVR4 compatibility. The old -V 616behaviour is available via --verbose. 617 618Changes in version 2.4: 619 620* New linker code, by Steve Chamberlain and Ian Taylor. For a.out and ecoff 621 formats (so far), this should result in considerable savings in time 622 and memory used while linking; slightly poorer performance than 623 before for formats not converted yet. 624 625* Command-line parsing is no longer done with flex. This means 626 oddball characters in filenames won't get treated as argument 627 separators. 628 629* HP-PA ELF support, by Jeff Law. (No SOM support yet.) 630 631* Mach i386 support, by David Mackenzie. 632 633* Irix 4 shared libraries are now supported (Irix 5 uses ELF, and ELF shared 634 libraries are not yet supported). 635 636* COFF shared libraries (as on SCO) should work as well. 637 638* The linker is disabled for Solaris. (Actually, it was in 2.3 also, I just 639 forgot to note it.) Some of their C library routines don't work when 640 statically linked, and the GNU linker doesn't support dynamic linking yet. 641 642Changes in version 2.3: 643 644* Weak symbols are now supported. 645 646* ELF support has been added. The linker has been bootstrapped on 647 UnixWare and Solaris. 648 649* Alpha OSF/1 support has been added (non dynamic linking only). 650 651Changes in version 2.2: 652 653* The `bfd' library has been updated to reduce a.out-format string 654 table size. The effect of this is that files linked from many input 655 files with duplicate symbols (`-g' debugging records, or identical 656 static symbols) should be much smaller. 657 658Changes in version 2.1: 659 660* The ld -ySYMBOL flag (to trace references to SYMBOL) is now implemented. 661 662* There is now support for writing ECOFF files, so ld and the 663 other utilities should work on Risc/Ultrix and Irix. 664 665 666Copyright (C) 2012-2017 Free Software Foundation, Inc. 667 668Copying and distribution of this file, with or without modification, 669are permitted in any medium without royalty provided the copyright 670notice and this notice are preserved. 671 672Local variables: 673fill-column: 79 674End: 675