| ======================= |
| lld 8.0.0 Release Notes |
| ======================= |
| |
| .. contents:: |
| :local: |
| |
| Introduction |
| ============ |
| |
| lld is a high-performance linker that supports ELF (Unix), COFF (Windows), |
| Mach-O (macOS), MinGW and WebAssembly. lld is command-line-compatible with |
| GNU linkers and Microsoft link.exe and is significantly faster than the |
| system default linkers. |
| |
| lld 8.0.0 has lots of feature improvements and bug fixes. |
| |
| Non-comprehensive list of changes in this release |
| ================================================= |
| |
| ELF Improvements |
| ---------------- |
| |
| * lld now supports RISC-V. (`r339364 |
| <https://reviews.llvm.org/rL339364>`_) |
| |
| * Default image base address has changed from 65536 to 2 MiB for i386 |
| and 4 MiB for AArch64 to make lld-generated executables work better |
| with automatic superpage promotion. FreeBSD can promote contiguous |
| non-superpages to a superpage if they are aligned to the superpage |
| size. (`r342746 <https://reviews.llvm.org/rL342746>`_) |
| |
| * lld now attempts to place a ``.note`` segment in the first page of a |
| generated file, so that you can find some important information |
| (``.note.gnu.build-id`` in particular) in a core file even if a core |
| file is truncated by ulimit. |
| (`r349524 <https://reviews.llvm.org/rL349524>`_) |
| |
| * lld now reports an error if ``_GLOBAL_OFFSET_TABLE_`` symbol is |
| defined by an input object file, as the symbol is supposed to be |
| synthesized by the linker. |
| (`r347854 <https://reviews.llvm.org/rL347854>`_) |
| |
| * lld/Hexagon can now link Linux kernel and musl libc for Qualcomm |
| Hexagon ISA. |
| |
| * Initial MSP430 ISA support has landed. |
| |
| * lld now uses the ``sigrie`` instruction as a trap instruction for |
| MIPS targets. |
| |
| * lld now creates a TLS segment for AArch64 with a slightly larger |
| alignment requirement, so that the loader makes a few bytes room |
| before each TLS segment at runtime. The aim of this change is to |
| make room to accomodate nonstandard Android TLS slots while keeping |
| the compatibility with the standard AArch64 ABI. |
| (`r350681 <https://reviews.llvm.org/rL350681>`_) |
| |
| * The following flags have been added: ``--call-graph-profile``, |
| ``--no-call-graph-profile``, ``--warn-ifunc-textrel``, |
| ``-z interpose``, ``-z global``, ``-z nodefaultlib`` |
| |
| COFF Improvements |
| ----------------- |
| |
| * PDB GUID is set to hash of PDB contents instead to a random byte |
| sequence for build reproducibility. |
| |
| * ``/pdbsourcepath:`` is now also used to make ``"cwd"``, ``"exe"``, ``"pdb"`` |
| in the env block of PDB outputs absolute if they are relative, and to make |
| paths to obj files referenced in PDB outputs absolute if they are relative. |
| Together with the previous item, this makes it possible to generate |
| executables and PDBs that are fully deterministic and independent of the |
| absolute path to the build directory, so that different machines building |
| the same code in different directories can produce exactly the same output. |
| |
| * The following flags have been added: ``/force:multiple`` |
| |
| * lld now can link against import libraries produced by GNU tools. |
| |
| * lld can create thunks for ARM and ARM64, to allow linking larger images |
| (over 16 MB for ARM and over 128 MB for ARM64) |
| |
| * Several speed and memory usage improvements. |
| |
| * lld now creates debug info for typedefs. |
| |
| * lld can now link obj files produced by ``cl.exe /Z7 /Yc``. |
| |
| * lld now understands ``%_PDB%`` and ``%_EXT%`` in ``/pdbaltpath:``. |
| |
| * Undefined symbols are now printed in demangled form in addition to raw form. |
| |
| MinGW Improvements |
| ------------------ |
| |
| * lld can now automatically import data variables from DLLs without the |
| use of the dllimport attribute. |
| |
| * lld can now use existing normal MinGW sysroots with import libraries and |
| CRT startup object files for GNU binutils. lld can handle most object |
| files produced by GCC, and thus works as a drop-in replacement for |
| ld.bfd in such environments. (There are known issues with linking crtend.o |
| from GCC in setups with DWARF exceptions though, where object files are |
| linked in a different order than with GNU ld, inserting a DWARF exception |
| table terminator too early.) |
| |
| * lld now supports COFF embedded directives for linking to nondefault |
| libraries, just like for the normal COFF target. |
| |
| * Actually generate a codeview build id signature, even if not creating a PDB. |
| Previously, the ``--build-id`` option did not actually generate a build id |
| unless ``--pdb`` was specified. |
| |
| WebAssembly Improvements |
| ------------------------ |
| |
| * Add initial support for creating shared libraries (-shared). |
| Note: The shared library format is still under active development and may |
| undergo significant changes in future versions. |
| See: https://github.com/WebAssembly/tool-conventions/blob/master/DynamicLinking.md |
