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100 lines
3.7 KiB
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=======================
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LLD 6.0.0 Release Notes
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=======================
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.. contents::
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:local:
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Introduction
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============
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This document contains the release notes for the lld linker, release 6.0.0.
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Here we describe the status of lld, including major improvements
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from the previous release. All lld releases may be downloaded
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from the `LLVM releases web site <http://llvm.org/releases/>`_.
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Non-comprehensive list of changes in this release
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=================================================
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ELF Improvements
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----------------
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* A lot of bugs and compatibility issues have been identified and fixed as a
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result of people using lld 5.0 as a standard system linker. In particular,
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linker script and version script support has significantly improved that
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it should be able to handle almost all scripts.
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* A mitigation for Spectre v2 has been implemented. If you pass ``-z
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retpolineplt``, lld uses RET instruction instead of JMP instruction in PLT.
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The option is available for x86 and x86-64.
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* Identical Code Folding (ICF) now de-duplicates .eh_frame entries, so lld now
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generates slightly smaller outputs than before when you pass ``--icf=all``.
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* Analysis for ``--as-needed`` is now done after garbage collection. If garbage
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collector eliminates all sections that use some library, that library is
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eliminated from DT_NEEDED tags. Previously, the analysis ran before garbage
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collection.
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* Size of code segment is now always rounded up to page size to make sure that
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unused bytes at end of code segment is filled with trap instructions (such
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as INT3) instead of zeros.
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* lld is now able to generate Android-style compact dynamic relocation table.
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You can turn on the feature by passing ``--pack-dyn-relocs=android``.
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* Debug information is used in more cases when reporting errors.
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* ``--gdb-index`` gets faster than before.
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* String merging is now multi-threaded, which makes ``-O2`` faster.
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* ``--hash-style=both`` is now default instead of ``--hash-style=sysv`` to
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match the behavior of recent versions of GNU linkers.
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* ARM PLT entries automatically use short or long variants.
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* lld can now identify and patch a code sequence that triggers AArch64 errata 843419.
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Add ``--fix-cortex-a53-843419`` to enable the feature.
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* lld can now generate thunks for out of range branches.
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* MIPS port now generates all output dynamic relocations using Elf_Rel format only.
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* Added handling of the R_MIPS_26 relocation in case of N32/N64 ABIs and
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generating proper PLT entries.
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* The following options have been added: ``--icf=none`` ``-z muldefs``
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``--plugin-opt`` ``--no-eh-frame-hdr`` ``--no-gdb-index``
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``--orphan-handling={place,discard,warn,error}``
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``--pack-dyn-relocs={none,android}`` ``--no-omagic``
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``--no-print-gc-sections`` ``--ignore-function-address-equality`` ``-z
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retpolineplt`` ``--print-icf-sections`` ``--no-pie``
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COFF Improvements
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-----------------
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* A GNU ld style frontend for the COFF linker has been added for MinGW.
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In MinGW environments, the linker is invoked with GNU ld style parameters;
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which lld previously only supported when used as an ELF linker. When
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a PE/COFF target is chosen, those parameters are rewritten into the
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lld-link style parameters and the COFF linker is invoked instead.
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* Initial support for the ARM64 architecture has been added.
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* New ``--version`` flag.
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* Significantly improved support for writing PDB Files.
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* New ``--rsp-quoting`` flag, like ``clang-cl``.
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* ``/manifestuac:no`` no longer incorrectly disables ``/manifestdependency:``.
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* Only write ``.manifest`` files if ``/manifest`` is passed.
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WebAssembly Improvements
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------------------------
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* Initial version of WebAssembly support has landed. You can invoke the
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WebAssembly linker by ``wasm-ld``.
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