===========================
lld |release| Release Notes
===========================
.. contents::
:local:
.. only:: PreRelease
.. warning::
These are in-progress notes for the upcoming LLVM |release| release.
Release notes for previous releases can be found on
`the Download Page <https://releases.llvm.org/download.html>`_.
Introduction
============
This document contains the release notes for the lld linker, release |release|.
Here we describe the status of lld, including major improvements
from the previous release. All lld releases may be downloaded
from the `LLVM releases web site <https://llvm.org/releases/>`_.
Non-comprehensive list of changes in this release
=================================================
ELF Improvements
----------------
* ``ELFCOMPRESS_ZSTD`` compressed input sections are now supported.
(`D129406 <https://reviews.llvm.org/D129406>`_)
* ``--compress-debug-sections=zstd`` is now available to compress debug
sections with zstd (``ELFCOMPRESS_ZSTD``).
(`D133548 <https://reviews.llvm.org/D133548>`_)
* ``--no-warnings``/``-w`` is now available to suppress warnings.
(`D136569 <https://reviews.llvm.org/D136569>`_)
* ``DT_RISCV_VARIANT_CC`` is now produced if at least one ``R_RISCV_JUMP_SLOT``
relocation references a symbol with the ``STO_RISCV_VARIANT_CC`` bit.
(`D107951 <https://reviews.llvm.org/D107951>`_)
* When ``--threads=`` is not specified, the number of concurrency is now capped to 16.
A large ``--thread=`` can harm performance, especially with some system
malloc implementations like glibc's.
(`D147493 <https://reviews.llvm.org/D147493>`_)
* ``--remap-inputs=`` and ``--remap-inputs-file=`` are added to remap input files.
(`D148859 <https://reviews.llvm.org/D148859>`_)
* ``--lto=`` is now available to support ``clang -funified-lto``
(`D123805 <https://reviews.llvm.org/D123805>`_)
* ``--lto-CGO[0-3]`` is now available to control ``CodeGenOptLevel`` independent of the LTO optimization level.
(`D141970 <https://reviews.llvm.org/D141970>`_)
* ``--check-dynamic-relocations=`` is now correct 32-bit targets when the addend is larger than 0x80000000.
(`D149347 <https://reviews.llvm.org/D149347>`_)
* ``--print-memory-usage`` has been implemented for memory regions.
(`D150644 <https://reviews.llvm.org/D150644>`_)
* ``SHF_MERGE``, ``--icf=``, and ``--build-id=fast`` have switched to 64-bit xxh3.
(`D154813 <https://reviews.llvm.org/D154813>`_)
* Quoted output section names can now be used in linker scripts.
(`#60496 <https://github.com/llvm/llvm-project/issues/60496>`_)
* ``MEMORY`` can now be used without a ``SECTIONS`` command.
(`D145132 <https://reviews.llvm.org/D145132>`_)
* ``REVERSE`` can now be used in input section descriptions to reverse the order of input sections.
(`D145381 <https://reviews.llvm.org/D145381>`_)
* Program header assignment can now be used within ``OVERLAY``. This functionality was accidentally lost in 2020.
(`D150445 <https://reviews.llvm.org/D150445>`_)
* Operators ``^`` and ``^=`` can now be used in linker scripts.
* LoongArch is now supported.
* ``DT_AARCH64_MEMTAG_*`` dynamic tags are now supported.
(`D143769 <https://reviews.llvm.org/D143769>`_)
* AArch32 port now supports BE-8 and BE-32 modes for big-endian.
(`D140201 <https://reviews.llvm.org/D140201>`_)
(`D140202 <https://reviews.llvm.org/D140202>`_)
(`D150870 <https://reviews.llvm.org/D150870>`_)
* ``R_ARM_THM_ALU_ABS_G*`` relocations are now supported.
(`D153407 <https://reviews.llvm.org/D153407>`_)
* ``.ARM.exidx`` sections may start at non-zero output section offset.
(`D148033 <https://reviews.llvm.org/D148033>`_)
* Arm Cortex-M Security Extensions is now implemented.
(`D139092 <https://reviews.llvm.org/D139092>`_)
* BTI landing pads are now added to PLT entries accessed by range extension thunks or relative vtables.
(`D148704 <https://reviews.llvm.org/D148704>`_)
(`D153264 <https://reviews.llvm.org/D153264>`_)
* AArch64 short range thunk has been implemented to mitigate the performance loss of a long range thunk.
(`D148701 <https://reviews.llvm.org/D148701>`_)
* ``R_AVR_8_LO8/R_AVR_8_HI8/R_AVR_8_HLO8/R_AVR_LO8_LDI_GS/R_AVR_HI8_LDI_GS`` have been implemented.
(`D147100 <https://reviews.llvm.org/D147100>`_)
(`D147364 <https://reviews.llvm.org/D147364>`_)
* ``--no-power10-stubs`` now works for PowerPC64.
* ``DT_PPC64_OPT`` is now supported;
(`D150631 <https://reviews.llvm.org/D150631>`_)
* ``PT_RISCV_ATTRIBUTES`` is added to include the SHT_RISCV_ATTRIBUTES section.
(`D152065 <https://reviews.llvm.org/D152065>`_)
* ``R_RISCV_PLT32`` is added to support C++ relative vtables.
(`D143115 <https://reviews.llvm.org/D143115>`_)
* RISC-V global pointer relaxation has been implemented. Specify ``--relax-gp`` to enable the linker relaxation.
(`D143673 <https://reviews.llvm.org/D143673>`_)
* The symbol value of ``foo`` is correctly handled when ``--wrap=foo`` and RISC-V linker relaxation are used.
(`D151768 <https://reviews.llvm.org/D151768>`_)
* x86-64 large data sections are now placed away from code sections to alleviate relocation overflow pressure.
(`D150510 <https://reviews.llvm.org/D150510>`_)
* ``--fat-lto-objects`` option is added to support LLVM FatLTO.
Without ``--fat-lto-objects``, LLD will link LLVM FatLTO objects using the
relocatable object file. (`D146778 <https://reviews.llvm.org/D146778>`_)
* common-page-size can now be larger than the system page-size.
(`#57618 <https://github.com/llvm/llvm-project/issues/57618>`_)
Breaking changes
----------------
COFF Improvements
-----------------
* Added support for ``--time-trace`` and associated ``--time-trace-granularity``.
This generates a .json profile trace of the linker execution.
MinGW Improvements
------------------
MachO Improvements
------------------
WebAssembly Improvements
------------------------
Fixes
#####