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| -rw-r--r-- | lld/docs/ReleaseNotes.rst | 133 |
1 files changed, 127 insertions, 6 deletions
diff --git a/lld/docs/ReleaseNotes.rst b/lld/docs/ReleaseNotes.rst index 513ad37e278e..466a7f707354 100644 --- a/lld/docs/ReleaseNotes.rst +++ b/lld/docs/ReleaseNotes.rst @@ -24,22 +24,143 @@ Non-comprehensive list of changes in this release ELF Improvements ---------------- -* New ``--time-trace`` option records a time trace file that can be viewed in +* ``--lto-emit-asm`` is added to emit assembly output for debugging purposes. + (`D77231 <https://reviews.llvm.org/D77231>`_) +* ``--lto-whole-program-visibility`` is added to support LTO whole-program devirtualization. + (`D71913 <https://reviews.llvm.org/D71913>`_) +* ``--print-archive-stats=`` is added to print the number of members and the number of fetched members for each archive. + The feature is similar to GNU gold's ``--print-symbol-counts=``. + (`D78983 <https://reviews.llvm.org/D78983>`_) +* ``--shuffle-sections=`` is added to introduce randomization in the output to help reduce measurement bias and detect static initialization order fiasco. + (`D74791 <https://reviews.llvm.org/D74791>`_) + (`D74887 <https://reviews.llvm.org/D74887>`_) +* ``--time-trace`` is added. It records a time trace file that can be viewed in chrome://tracing. The file can be specified with ``--time-trace-file``. Trace granularity can be specified with ``--time-trace-granularity``. (`D71060 <https://reviews.llvm.org/D71060>`_) -* For ARM architectures the default max page size was increased to 64k. - This increases compatibility with systems where a non standard page - size was configured. This also is inline with GNU ld defaults. - (`D77330 <https://reviews.llvm.org/D77330>`_) -* ... +* ``--thinlto-single-module`` is added to compile a subset of modules in ThinLTO for debugging purposes. + (`D80406 <https://reviews.llvm.org/D80406>`_) +* ``--unique`` is added to create separate output sections for orphan sections. + (`D75536 <https://reviews.llvm.org/D75536>`_) +* ``--warn-backrefs`` has been improved to emulate GNU ld's archive semantics. + If a link passes with warnings from ``--warn-backrefs``, it almost assuredly + means that the link will fail with GNU ld, or the symbol will get different + resolutions in GNU ld and LLD. ``--warn-backrefs-exclude=`` is added to + exclude known issues. + (`D77522 <https://reviews.llvm.org/D77522>`_) + (`D77630 <https://reviews.llvm.org/D77630>`_) + (`D77512 <https://reviews.llvm.org/D77512>`_) +* ``--no-relax`` is accepted but ignored. The Linux kernel's RISC-V port uses this option. + (`D81359 <https://reviews.llvm.org/D81359>`_) +* ``--rosegment`` (default) is added to complement ``--no-rosegment``. + GNU gold from 2.35 onwards support both options. +* ``--threads=N`` is added. The default uses all threads. + (`D76885 <https://reviews.llvm.org/D76885>`_) +* ``--wrap`` has better compatibility with GNU ld. +* ``-z dead-reloc-in-nonalloc=<section_glob>=<value>`` is added to resolve an absolute relocation + referencing a discarded symbol. + (`D83264 <https://reviews.llvm.org/D83264>`_) +* Changed tombstone values to (``.debug_ranges``/``.debug_loc``) 1 and (other ``.debug_*``) 0. + A tombstone value is the computed value of a relocation referencing a discarded symbol (``--gc-sections``, ICF or ``/DISCARD/``). + (`D84825 <https://reviews.llvm.org/D84825>`_) + In the future many .debug_* may switch to 0xffffffff/0xffffffffffffffff as the tombstone value. +* ``-z keep-text-section-prefix`` moves ``.text.unknown.*`` input sections to ``.text.unknown``. +* ``-z rel`` and ``-z rela`` are added to select the REL/RELA format for dynamic relocations. + The default is target specific and typically matches the form used in relocatable objects. +* ``-z start-stop-visibility={default,protected,internal,hidden}`` is added. + GNU ld/gold from 2.35 onwards support this option. + (`D55682 <https://reviews.llvm.org/D55682>`_) +* When ``-r`` or ``--emit-relocs`` is specified, the GNU ld compatible + ``--discard-all`` and ``--discard-locals`` semantics are implemented. + (`D77807 <https://reviews.llvm.org/D77807>`_) +* ``--emit-relocs --strip-debug`` can now be used together. + (`D74375 <https://reviews.llvm.org/D74375>`_) +* ``--gdb-index`` supports DWARF v5. + (`D79061 <https://reviews.llvm.org/D79061>`_) + (`D85579 <https://reviews.llvm.org/D85579>`_) +* ``-r`` allows SHT_X86_64_UNWIND to be merged into SHT_PROGBITS. + This allows clang/GCC produced object files to be mixed together. + (`D85785 <https://reviews.llvm.org/D85785>`_) +* Better linker script support related to output section alignments and LMA regions. + (`D74286 <https://reviews.llvm.org/D75724>`_) + (`D74297 <https://reviews.llvm.org/D75724>`_) + (`D75724 <https://reviews.llvm.org/D75724>`_) + (`D81986 <https://reviews.llvm.org/D81986>`_) +* In a input section description, the filename can be specified in double quotes. + ``archive:file`` syntax is added. + (`D72517 <https://reviews.llvm.org/D72517>`_) + (`D75100 <https://reviews.llvm.org/D75100>`_) +* Linker script specified empty ``(.init|.preinit|.fini)_array`` are allowed with RELRO. + (`D76915 <https://reviews.llvm.org/D76915>`_) +* ``INSERT AFTER`` and ``INSERT BEFORE`` work for orphan sections now. + (`D74375 <https://reviews.llvm.org/D74375>`_) +* ``INPUT_SECTION_FLAGS`` is supported in linker scripts. + (`D72745 <https://reviews.llvm.org/D72745>`_) +* ``DF_1_PIE`` is set for position-independent executables. + (`D80872 <https://reviews.llvm.org/D80872>`_) +* For a symbol assignment ``alias = aliasee;``, ``alias`` inherits the ``aliasee``'s symbol type. + (`D86263 <https://reviews.llvm.org/D86263>`_) +* ``SHT_GNU_verneed`` in shared objects are parsed, and versioned undefined symbols in shared objects are respected. + (`D80059 <https://reviews.llvm.org/D80059>`_) +* SHF_LINK_ORDER and non-SHF_LINK_ORDER sections can be mixed along as the SHF_LINK_ORDER components are contiguous. + (`D77007 <https://reviews.llvm.org/D77007>`_) +* An out-of-range relocation diagnostic mentions the referenced symbol now. + (`D73518 <https://reviews.llvm.org/D73518>`_) +* AArch64: ``R_AARCH64_PLT32`` is supported. + (`D81184 <https://reviews.llvm.org/D81184>`_) +* ARM: SBREL type relocations are supported. + (`D74375 <https://reviews.llvm.org/D74375>`_) +* ARM: ``R_ARM_ALU_PC_G0``, ``R_ARM_LDR_PC_G0``, ``R_ARM_THUMB_PC8`` and ``R_ARM_THUMB__PC12`` are supported. + (`D75349 <https://reviews.llvm.org/D75349>`_) + (`D77200 <https://reviews.llvm.org/D77200>`_) +* ARM: various improvements to .ARM.exidx: ``/DISCARD/`` support for a subset, out-of-range handling, support for non monotonic section order. + (`PR44824 <https://llvm.org/PR44824>`_) +* AVR: many relocation types are supported. + (`D78741 <https://reviews.llvm.org/D78741>`_) +* Hexagon: General Dynamic and some other relocation types are supported. +* PPC: Canonical PLT and range extension thunks with addends are supported. + (`D73399 <https://reviews.llvm.org/D73399>`_) + (`D73424 <https://reviews.llvm.org/D73424>`_) + (`D75394 <https://reviews.llvm.org/D75394>`_) +* PPC and PPC64: copy relocations. + (`D73255 <https://reviews.llvm.org/D73255>`_) +* PPC64: ``_savegpr[01]_{14..31}`` and ``_restgpr[01]_{14..31}`` can be synthesized. + (`D79977 <https://reviews.llvm.org/D79977>`_) +* PPC64: ``R_PPC64_GOT_PCREL34`` and ``R_PPC64_REL24_NOTOC`` are supported. r2 save stub is supported. + (`D81948 <https://reviews.llvm.org/D81948>`_) + (`D82950 <https://reviews.llvm.org/D82950>`_) + (`D82816 <https://reviews.llvm.org/D82816>`_) +* RISC-V: ``R_RISCV_IRELATIVE`` is supported. + (`D74022 <https://reviews.llvm.org/D74022>`_) +* RISC-V: ``R_RISCV_ALIGN`` is errored because GNU ld style linker relaxation is not supported. + (`D71820 <https://reviews.llvm.org/D71820>`_) +* SPARCv9: more relocation types are supported. + (`D77672 <https://reviews.llvm.org/D77672>`_) Breaking changes ---------------- * One-dash form of some long option (``--thinlto-*``, ``--lto-*``, ``--shuffle-sections=``) are no longer supported. + (`D79371 <https://reviews.llvm.org/D79371>`_) * ``--export-dynamic-symbol`` no longer implies ``-u``. + The new behavior matches GNU ld from binutils 2.35 onwards. + (`D80487 <https://reviews.llvm.org/D80487>`_) +* ARM: the default max page size was increased from 4096 to 65536. + This increases compatibility with systems where a non standard page + size was configured. This also is inline with GNU ld defaults. + (`D77330 <https://reviews.llvm.org/D77330>`_) +* ARM: for non-STT_FUNC symbols, Thumb interworking thunks are not added and BL/BLX are not substituted. + (`D73474 <https://reviews.llvm.org/D73474>`_) + (`D73542 <https://reviews.llvm.org/D73542>`_) +* AArch64: ``--force-bti`` is renamed to ``-z force-bti`. ``--pac-plt`` is renamed to ``-z pac-plt``. + This change is compatibile with GNU ld. +* A readonly ``PT_LOAD`` is created in the presence of a ``SECTIONS`` command. + The new behavior is consistent with the longstanding behavior in the absence of a SECTIONS command. +* Orphan section names like ``.rodata.foo`` and ``.text.foo`` are not grouped into ``.rodata`` and ``.text`` in the presence of a ``SECTIONS`` command. + The new behavior matches GNU ld. + (`D75225 <https://reviews.llvm.org/D75225>`_) +* ``--no-threads`` is removed. Use ``--threads=1`` instead. ``--threads`` (no-op) is removed. COFF Improvements ----------------- |