Some common options:
- * ``-DLLVM_ENABLE_PROJECTS='...'`` --- semicolon-separated list of the LLVM
- sub-projects you'd like to additionally build. Can include any of: clang,
- clang-tools-extra, compiler-rt,cross-project-tests, flang, libc, libclc,
- libcxx, libcxxabi, libunwind, lld, lldb, mlir, openmp, polly, or pstl.
+ * ``-DLLVM_ENABLE_PROJECTS='...'`` and ``-DLLVM_ENABLE_RUNTIMES='...'`` ---
+ semicolon-separated list of the LLVM sub-projects and runtimes you'd like to
+ additionally build. ``LLVM_ENABLE_PROJECTS`` can include any of: clang,
+ clang-tools-extra, cross-project-tests, flang, libc, libclc, lld, lldb,
+ mlir, openmp, polly, or pstl. ``LLVM_ENABLE_RUNTIMES`` can include any of
+ libcxx, libcxxabi, libunwind, compiler-rt, libc or openmp. Some runtime
+ projects can be specified either in ``LLVM_ENABLE_PROJECTS`` or in
+ ``LLVM_ENABLE_RUNTIMES``.
For example, to build LLVM, Clang, libcxx, and libcxxabi, use
- ``-DLLVM_ENABLE_PROJECTS="clang;libcxx;libcxxabi"``.
+ ``-DLLVM_ENABLE_PROJECTS="clang" -DLLVM_ENABLE_RUNTIMES="libcxx;libcxxabi"``.
* ``-DCMAKE_INSTALL_PREFIX=directory`` --- Specify for *directory* the full
path name of where you want the LLVM tools and libraries to be installed
- (default ``/usr/local``).
+ (default ``/usr/local``). Be careful if you install runtime libraries: if
+ your system uses those provided by LLVM (like libc++ or libc++abi), you
+ must not overwrite your system's copy of those libraries, since that
+ could render your system unusable. In general, using something like
+ ``/usr`` is not advised, but ``/usr/local`` is fine.
* ``-DCMAKE_BUILD_TYPE=type`` --- Valid options for *type* are Debug,
Release, RelWithDebInfo, and MinSizeRel. Default is Debug.
implements taken branch sampling (`-b/-j` flag). For that reason, it may not be possible to
collect the accurate profile in a virtualized environment, e.g. in the cloud.
We do support regular sampling profiles, but the performance
-improvements are expected to be more modest.
+improvements are expected to be more modest.
```bash
$ mkdir ${TOPLEV}/stage3
$ cmake -G Ninja ${TOPLEV}/llvm-project/llvm -DLLVM_TARGETS_TO_BUILD=X86 \
-DCMAKE_BUILD_TYPE=Release \
-DCMAKE_C_COMPILER=gcc -DCMAKE_CXX_COMPILER=g++ -DCMAKE_ASM_COMPILER=gcc \
- -DLLVM_ENABLE_PROJECTS="clang;lld;compiler-rt" \
+ -DLLVM_ENABLE_PROJECTS="clang;lld" \
+ -DLLVM_ENABLE_RUNTIMES="compiler-rt" \
-DCOMPILER_RT_BUILD_SANITIZERS=OFF -DCOMPILER_RT_BUILD_XRAY=OFF \
-DCOMPILER_RT_BUILD_LIBFUZZER=OFF \
-DCMAKE_INSTALL_PREFIX=${TOPLEV}/stage1/install
.. code-block:: console
+ mkdir libcxx-build
cd libcxx-build
# An example using ninja
- cmake -GNinja path/to/llvm-project/llvm \
+ cmake -GNinja -S <monorepo-root>/runtimes \
-DCMAKE_C_COMPILER=clang \
-DCMAKE_CXX_COMPILER=clang++ \
-DLLVM_USE_SANITIZER="DataFlow" \
- -DLLVM_ENABLE_LIBCXX=ON \
- -DLLVM_ENABLE_PROJECTS="libcxx;libcxxabi"
+ -DLLVM_ENABLE_RUNTIMES="libcxx;libcxxabi"
ninja cxx cxxabi
^^^^^^^^^^^^^^^^
LLVM's unwinder library is part of the llvm-project git repository. To
-build it, pass ``-DLLVM_ENABLE_PROJECTS=libunwind`` to the cmake invocation.
+build it, pass ``-DLLVM_ENABLE_RUNTIMES=libunwind`` to the cmake invocation.
If using libc++abi, you may need to configure it to use libunwind
rather than libgcc_s by passing ``-DLIBCXXABI_USE_LLVM_UNWINDER=YES``
<p>Generally, you need to build LLVM/Clang in order to build compiler-rt. You
can build it either together with llvm and clang, or separately.
- <p>To build it together, simply add compiler-rt to the -DLLVM_ENABLE_PROJECTS= option to
+ <p>To build it together, simply add compiler-rt to the -DLLVM_ENABLE_RUNTIMES= option to
cmake.
<p>To build it separately, first
and
also review [how flang uses modern C++ features](docs/C++17.md).
-If you are interested in writing new documentation, follow
-[markdown style guide from LLVM](https://github.com/llvm/llvm-project/blob/main/llvm/docs/MarkdownQuickstartTemplate.md).
+If you are interested in writing new documentation, follow
+[LLVM's Markdown style guide](https://github.com/llvm/llvm-project/blob/main/llvm/docs/MarkdownQuickstartTemplate.md).
## Building flang
There are two ways to build flang. The first method is to build it at the same
floating point numbers. It's not needed to run the automated tests.
Here's a complete set of commands to clone all of the necessary source and do
-the build.
+the build.
First clone the source:
```bash
-DLLVM_TARGETS_TO_BUILD=host \
-DCMAKE_INSTALL_PREFIX=$INSTALLDIR
-DLLVM_LIT_ARGS=-v \
- -DLLVM_ENABLE_PROJECTS="clang;mlir;flang;compiler-rt"
+ -DLLVM_ENABLE_PROJECTS="clang;mlir;flang" \
+ -DLLVM_ENABLE_RUNTIMES="compiler-rt"
ninja
```
.. code-block:: bash
- $ cmake -G Ninja -S llvm -B build \
- -DLLVM_ENABLE_PROJECTS="libcxx" \
+ $ cmake -G Ninja -S runtimes -B build \
+ -DLLVM_ENABLE_RUNTIMES="libcxx" \
-DLIBCXX_CXX_ABI=libstdc++ \
-DLIBCXX_CXX_ABI_INCLUDE_PATHS="/usr/include/c++/4.7/;/usr/include/c++/4.7/x86_64-linux-gnu/"
$ ninja -C build install-cxx
.. code-block:: bash
- $ cmake -G Ninja -S llvm -B build \
- -DLLVM_ENABLE_PROJECTS="libcxx" \
+ $ cmake -G Ninja -S runtimes -B build \
+ -DLLVM_ENABLE_RUNTIMES="libcxx" \
-DLIBCXX_CXX_ABI=libcxxrt \
-DLIBCXX_CXX_ABI_INCLUDE_PATHS=path/to/libcxxrt-sources/src
$ ninja -C build install-cxx
* ``cd where you want to build llvm``
* ``mkdir build``
* ``cd build``
- * ``cmake -G <generator> -DLLVM_ENABLE_PROJECTS=libunwind [options] <path to llvm sources>``
+ * ``cmake -G <generator> -DLLVM_ENABLE_RUNTIMES=libunwind [options] <llvm-monorepo>/runtimes``
For more information about configuring libunwind see :ref:`CMake Options`.
This section provides documentation of the CMake options that are intended to
help construct distributions. This is not an exhaustive list, and many
additional options are documented in the :doc:`CMake` page. Some key options
-that are already documented include: *LLVM_TARGETS_TO_BUILD*,
-*LLVM_ENABLE_PROJECTS*, *LLVM_BUILD_LLVM_DYLIB*, and *LLVM_LINK_LLVM_DYLIB*.
+that are already documented include: *LLVM_TARGETS_TO_BUILD*, *LLVM_ENABLE_PROJECTS*,
+*LLVM_ENABLE_RUNTIMES*, *LLVM_BUILD_LLVM_DYLIB*, and *LLVM_LINK_LLVM_DYLIB*.
**LLVM_ENABLE_RUNTIMES**:STRING
When building a distribution that includes LLVM runtime projects (i.e. libcxx,
Control which projects are enabled. For example you may want to work on clang
or lldb by specifying ``-DLLVM_ENABLE_PROJECTS="clang;lldb"``.
+**LLVM_ENABLE_RUNTIMES**:STRING
+ Control which runtimes are enabled. For example you may want to work on
+ libc++ or libc++abi by specifying ``-DLLVM_ENABLE_RUNTIMES="libcxx;libcxxabi"``.
+
**LLVM_LIBDIR_SUFFIX**:STRING
Extra suffix to append to the directory where libraries are to be
installed. On a 64-bit architecture, one could use ``-DLLVM_LIBDIR_SUFFIX=64``
**LLVM_ENABLE_PROJECTS**:STRING
Semicolon-separated list of projects to build, or *all* for building all
- (clang, lldb, compiler-rt, lld, polly, etc) projects. This flag assumes
- that projects are checked out side-by-side and not nested, i.e. clang
- needs to be in parallel of llvm instead of nested in `llvm/tools`.
- This feature allows to have one build for only LLVM and another for clang+llvm
- using the same source checkout.
+ (clang, lldb, lld, polly, etc) projects. This flag assumes that projects
+ are checked out side-by-side and not nested, i.e. clang needs to be in
+ parallel of llvm instead of nested in `llvm/tools`. This feature allows
+ to have one build for only LLVM and another for clang+llvm using the same
+ source checkout.
The full list is:
- ``clang;clang-tools-extra;compiler-rt;cross-project-tests;libc;libclc;lld;lldb;openmp;polly;pstl``
+ ``clang;clang-tools-extra;cross-project-tests;libc;libclc;lld;lldb;openmp;polly;pstl``
**LLVM_ENABLE_RUNTIMES**:STRING
- Build libc++, libc++abi or other projects using that a just-built compiler.
- This is the correct way to build libc++ when putting together a toolchain.
+ Build libc++, libc++abi, libunwind or compiler-rt using the just-built compiler.
+ This is the correct way to build runtimes when putting together a toolchain.
It will build the builtins separately from the other runtimes to preserve
correct dependency ordering. If you want to build the runtimes using a system
compiler, see the `libc++ documentation <https://libcxx.llvm.org/BuildingLibcxx.html>`_.
| | other LLVM subprojects to additionally build. (Only|
| | effective when using a side-by-side project layout |
| | e.g. via git). The default list is empty. Can |
-| | include: clang, clang-tools-extra, compiler-rt, |
-| | cross-project-tests, flang, libc, libclc, libcxx, |
-| | libcxxabi, libunwind, lld, lldb, mlir, openmp, |
-| | polly, or pstl. |
+| | include: clang, clang-tools-extra, |
+| | cross-project-tests, flang, libc, libclc, lld, |
+| | lldb, mlir, openmp, polly, or pstl. |
++-------------------------+----------------------------------------------------+
+| LLVM_ENABLE_RUNTIMES | A semicolon-delimited list selecting which of the |
+| | runtimes to build. (Only effective when using the |
+| | full monorepo layout). The default list is empty. |
+| | Can include: compiler-rt, libc, libcxx, libcxxabi, |
+| | libunwind, or openmp. |
+-------------------------+----------------------------------------------------+
| LLVM_ENABLE_SPHINX | Build sphinx-based documentation from the source |
| | code. This is disabled by default because it is |
compiling more than one project, separate the items with a semicolon. Should
you run into issues with the semicolon, try surrounding it with single quotes.
+* -DLLVM_ENABLE_RUNTIMES
+ Set this equal to the runtimes you wish to compile (e.g. libcxx, libcxxabi, etc.)
+ If compiling more than one runtime, separate the items with a semicolon. Should
+ you run into issues with the semicolon, try surrounding it with single quotes.
+
* -DCLANG_ENABLE_STATIC_ANALYZER
Set this option to OFF if you do not require the clang static analyzer. This
should improve your build time slightly.