diff --git a/lld/docs/MachO/index.rst b/lld/docs/MachO/index.rst new file mode 100644 --- /dev/null +++ b/lld/docs/MachO/index.rst @@ -0,0 +1,76 @@ +LLD - The LLVM Linker +===================== + +LLD is a linker from the LLVM project that is a drop-in replacement +for system linkers and runs much faster than them. It also provides +features that are useful for toolchain developers. This document +will describe the Mach-O port. + +Features +-------- + +- LLD is a drop-in replacement for Apple's Mach-O linker, ld64, that accepts the + same command line arguments. + +- LLD is very fast. When you link a large program on a multicore + machine, you can expect that LLD runs more than twice as fast as the ld64 linker. + +Download +-------- + +LLD is available as a pre-built binary by going to the [latest release](https://github.com/llvm/llvm-project/releases), +downloading the appropriate bundle (``clang+llvm---.tar.xz``), +decompressing it, and locating the binary at ``bin/ld64.lld``. Note +that if ``ld64.lld`` is moved out of ``bin``, it must still be accompanied +by its sibling file ``lld``. + +Build +----- + +If you have already checked out LLVM using SVN, you can check out LLD +under ``tools`` directory just like you probably did for clang. For the +details, see `Getting Started with the LLVM System +`_. + +If you haven't checked out LLVM, the easiest way to build LLD is to +check out the entire LLVM projects/sub-projects from a git mirror and +build that tree. You need `cmake` and of course a C++ compiler. + +.. code-block:: console + + $ git clone https://github.com/llvm/llvm-project llvm-project + $ mkdir build + $ cd build + $ cmake -DCMAKE_BUILD_TYPE=Release -DLLVM_ENABLE_PROJECTS=lld -DCMAKE_INSTALL_PREFIX=/usr/local ../llvm-project/llvm + $ make install + +Using LLD +--------- + +LLD can be used by adding ``-fuse-ld=/path/to/ld64.lld`` to the linker flags. +For Xcode, this can be done by adding it to "Other linker flags" in the build +settings. For Bazel, this can be done with ``--linkopt`` or with +[rules_apple_linker](https://github.com/keith/rules_apple_linker). +The user may also need to add ``-Wl,--deduplicate-literals`` in order +to match Apple's linker behavior more closely. + +Internals +--------- + +For the internals of the linker, please read :doc:`NewLLD`. It is a bit +outdated but the fundamental concepts remain valid. We'll update the +document soon. + +.. toctree:: + :maxdepth: 1 + + NewLLD + WebAssembly + windows_support + missingkeyfunction + error_handling_script + Partitions + ReleaseNotes + ELF/linker_script + ELF/start-stop-gc + ELF/warn_backrefs