forked from OSchip/llvm-project
259 lines
11 KiB
ReStructuredText
259 lines
11 KiB
ReStructuredText
==================================================================
|
|
Getting Started with the LLVM System using Microsoft Visual Studio
|
|
==================================================================
|
|
|
|
|
|
.. contents::
|
|
:local:
|
|
|
|
|
|
Overview
|
|
========
|
|
Welcome to LLVM on Windows! This document only covers LLVM on Windows using
|
|
Visual Studio, not WSL, mingw or cygwin. In order to get started, you first need
|
|
to know some basic information.
|
|
|
|
There are many different projects that compose LLVM. The first piece is the
|
|
LLVM suite. This contains all of the tools, libraries, and header files needed
|
|
to use LLVM. It contains an assembler, disassembler, bitcode analyzer and
|
|
bitcode optimizer. It also contains basic regression tests that can be used to
|
|
test the LLVM tools and the Clang front end.
|
|
|
|
The second piece is the `Clang <https://clang.llvm.org/>`_ front end. This
|
|
component compiles C, C++, Objective C, and Objective C++ code into LLVM
|
|
bitcode. Clang typically uses LLVM libraries to optimize the bitcode and emit
|
|
machine code. LLVM fully supports the COFF object file format, which is
|
|
compatible with all other existing Windows toolchains.
|
|
|
|
There are more LLVM projects which this document does not discuss.
|
|
|
|
|
|
Requirements
|
|
============
|
|
Before you begin to use the LLVM system, review the requirements given
|
|
below. This may save you some trouble by knowing ahead of time what hardware
|
|
and software you will need.
|
|
|
|
Hardware
|
|
--------
|
|
Any system that can adequately run Visual Studio 2019 is fine. The LLVM
|
|
source tree including the git index consumes approximately 3GB.
|
|
Object files, libraries and executables consume approximately 5GB in
|
|
Release mode and much more in Debug mode. SSD drive and >16GB RAM are
|
|
recommended.
|
|
|
|
|
|
Software
|
|
--------
|
|
You will need `Visual Studio <https://visualstudio.microsoft.com/>`_ 2019 or
|
|
later, with the latest Update installed. Visual Studio Community Edition
|
|
suffices.
|
|
|
|
You will also need the `CMake <http://www.cmake.org/>`_ build system since it
|
|
generates the project files you will use to build with. CMake is bundled with
|
|
Visual Studio 2019 so separate installation is not required. If you do install
|
|
CMake separately, Visual Studio 2022 will require CMake Version 3.21 or later.
|
|
|
|
If you would like to run the LLVM tests you will need `Python
|
|
<http://www.python.org/>`_. Version 3.6 and newer are known to work. You can
|
|
install Python with Visual Studio 2019, from the Microsoft store or from
|
|
the `Python web site <http://www.python.org/>`_. We recommend the latter since it
|
|
allows you to to adjust installation options.
|
|
|
|
You will need `Git for Windows <https://git-scm.com/>`_ with bash tools, too.
|
|
Git for Windows is also bundled with Visual Studio 2019.
|
|
|
|
|
|
Getting Started
|
|
===============
|
|
Here's the short story for getting up and running quickly with LLVM.
|
|
These instruction were tested with Visual Studio 2019 and Python 3.9.6:
|
|
|
|
1. Download and install `Visual Studio <https://visualstudio.microsoft.com/>`_.
|
|
2. In the Visual Studio installer, Workloads tab, select the
|
|
**Desktop development with C++** workload. Under Individual components tab,
|
|
select **Git for Windows**.
|
|
3. Complete the Visual Studio installation.
|
|
4. Download and install the latest `Python 3 release <http://www.python.org/>`_.
|
|
5. In the first install screen, select both **Install launcher for all users**
|
|
and **Add Python to the PATH**. This will allow installing psutil for all
|
|
users for the regression tests and make Python available from the command
|
|
line.
|
|
6. In the second install screen, select (again) **Install for all users** and
|
|
if you want to develop `lldb <https://lldb.llvm.org/>`_, selecting
|
|
**Download debug binaries** is useful.
|
|
7. Complete the Python installation.
|
|
8. Run a "Developer Command Prompt for VS 2019" **as administrator**. This command
|
|
prompt provides correct path and environment variables to Visual Studio and
|
|
the installed tools.
|
|
9. In the terminal window, type the commands:
|
|
|
|
.. code-block:: bat
|
|
|
|
c:
|
|
cd \
|
|
|
|
You may install the llvm sources in other location than ``c:\llvm`` but do not
|
|
install into a path containing spaces (e.g. ``c:\Documents and Settings\...``)
|
|
as it will fail.
|
|
|
|
10. Register the Microsoft Debug Interface Access (DIA) DLLs
|
|
|
|
.. code-block:: bat
|
|
|
|
regsvr32 "%VSINSTALLDIR%\DIA SDK\bin\msdia140.dll"
|
|
regsvr32 "%VSINSTALLDIR%\DIA SDK\bin\amd64\msdia140.dll"
|
|
|
|
The DIA library is required for LLVM PDB tests and
|
|
`LLDB development <https://lldb.llvm.org/resources/build.html>`_.
|
|
|
|
11. Install psutil and obtain LLVM source code:
|
|
|
|
.. code-block:: bat
|
|
|
|
pip install psutil
|
|
git clone https://github.com/llvm/llvm-project.git llvm
|
|
|
|
Instead of ``git clone`` you may download a compressed source distribution
|
|
from the `releases page <https://github.com/llvm/llvm-project/releases>`_.
|
|
Select the last link: ``Source code (zip)`` and unpack the downloaded file using
|
|
Windows Explorer built-in zip support or any other unzip tool.
|
|
|
|
12. Finally, configure LLVM using CMake:
|
|
|
|
.. code-block:: bat
|
|
|
|
cmake -S llvm\llvm -B build -DLLVM_ENABLE_PROJECTS=clang -DLLVM_TARGETS_TO_BUILD=X86 -Thost=x64
|
|
exit
|
|
|
|
``LLVM_ENABLE_PROJECTS`` specifies any additional LLVM projects you want to
|
|
build while ``LLVM_TARGETS_TO_BUILD`` selects the compiler targets. If
|
|
``LLVM_TARGETS_TO_BUILD`` is omitted by default all targets are built
|
|
slowing compilation and using more disk space.
|
|
See the :doc:`LLVM CMake guide <CMake>` for detailed information about
|
|
how to configure the LLVM build.
|
|
|
|
The ``cmake`` command line tool is bundled with Visual Studio but its GUI is
|
|
not. You may install `CMake <http://www.cmake.org/>`_ to use its GUI to change
|
|
CMake variables or modify the above command line.
|
|
|
|
* Once CMake is installed then the simplest way is to just start the
|
|
CMake GUI, select the directory where you have LLVM extracted to, and
|
|
the default options should all be fine. One option you may really
|
|
want to change, regardless of anything else, might be the
|
|
``CMAKE_INSTALL_PREFIX`` setting to select a directory to INSTALL to
|
|
once compiling is complete, although installation is not mandatory for
|
|
using LLVM. Another important option is ``LLVM_TARGETS_TO_BUILD``,
|
|
which controls the LLVM target architectures that are included on the
|
|
build.
|
|
* CMake generates project files for all build types. To select a specific
|
|
build type, use the Configuration manager from the VS IDE or the
|
|
``/property:Configuration`` command line option when using MSBuild.
|
|
* By default, the Visual Studio project files generated by CMake use the
|
|
32-bit toolset. If you are developing on a 64-bit version of Windows and
|
|
want to use the 64-bit toolset, pass the ``-Thost=x64`` flag when
|
|
generating the Visual Studio solution. This requires CMake 3.8.0 or later.
|
|
|
|
13. Start Visual Studio and select configuration:
|
|
|
|
In the directory you created the project files will have an ``llvm.sln``
|
|
file, just double-click on that to open Visual Studio. The default Visual
|
|
Studio configuration is **Debug** which is slow and generates a huge amount
|
|
of debug information on disk. For now, we recommend selecting **Release**
|
|
configuration for the LLVM project which will build the fastest or
|
|
**RelWithDebInfo** which is also several time larger than Release.
|
|
Another technique is to build all of LLVM in Release mode and change
|
|
compiler flags, disabling optimization and enabling debug information, only
|
|
for specific librares or source files you actually need to debug.
|
|
|
|
14. Test LLVM in Visual Studio:
|
|
|
|
You can run LLVM tests by merely building the project "check-all". The test
|
|
results will be shown in the VS output window. Once the build succeeds, you
|
|
have verified a working LLVM development environment!
|
|
|
|
You should not see any unexpected failures, but will see many unsupported
|
|
tests and expected failures:
|
|
|
|
::
|
|
|
|
114>Testing Time: 1124.66s
|
|
114> Skipped : 39
|
|
114> Unsupported : 21649
|
|
114> Passed : 51615
|
|
114> Expectedly Failed: 93
|
|
========== Build: 114 succeeded, 0 failed, 321 up-to-date, 0 skipped ==========``
|
|
|
|
Alternatives to manual installation
|
|
===================================
|
|
Instead of the steps above, to simplify the installation procedure you can use
|
|
`Chocolatey <https://chocolatey.org/>`_ as package manager.
|
|
After the `installation <https://chocolatey.org/install>`_ of Chocolatey,
|
|
run these commands in an admin shell to install the required tools:
|
|
|
|
.. code-block:: bat
|
|
|
|
choco install -y git cmake python3
|
|
pip3 install psutil
|
|
|
|
There is also a Windows
|
|
`Dockerfile <https://github.com/llvm/llvm-zorg/blob/main/buildbot/google/docker/windows-base-vscode2019/Dockerfile>`_
|
|
with the entire build tool chain. This can be used to test the build with a
|
|
tool chain different from your host installation or to create build servers.
|
|
|
|
Next steps
|
|
==========
|
|
1. Read the documentation.
|
|
2. Seriously, read the documentation.
|
|
3. Remember that you were warned twice about reading the documentation.
|
|
|
|
Test LLVM on the command line:
|
|
------------------------------
|
|
The LLVM tests can be run by changing directory to the llvm source
|
|
directory and running:
|
|
|
|
.. code-block:: bat
|
|
|
|
c:\llvm> python ..\build\Release\bin\llvm-lit.py llvm\test
|
|
|
|
This example assumes that Python is in your PATH variable, which would be
|
|
after **Add Python to the PATH** was selected during Python installation.
|
|
If you had opened a command window prior to Python installation, you would
|
|
have to close and reopen it to get the updated PATH.
|
|
|
|
A specific test or test directory can be run with:
|
|
|
|
.. code-block:: bat
|
|
|
|
c:\llvm> python ..\build\Release\bin\llvm-lit.py llvm\test\Transforms\Util
|
|
|
|
Build the LLVM Suite:
|
|
---------------------
|
|
* The projects may still be built individually, but to build them all do
|
|
not just select all of them in batch build (as some are meant as
|
|
configuration projects), but rather select and build just the
|
|
``ALL_BUILD`` project to build everything, or the ``INSTALL`` project,
|
|
which first builds the ``ALL_BUILD`` project, then installs the LLVM
|
|
headers, libs, and other useful things to the directory set by the
|
|
``CMAKE_INSTALL_PREFIX`` setting when you first configured CMake.
|
|
* The Fibonacci project is a sample program that uses the JIT. Modify the
|
|
project's debugging properties to provide a numeric command line argument
|
|
or run it from the command line. The program will print the
|
|
corresponding fibonacci value.
|
|
|
|
|
|
Links
|
|
=====
|
|
This document is just an **introduction** to how to use LLVM to do some simple
|
|
things... there are many more interesting and complicated things that you can
|
|
do that aren't documented here (but we'll gladly accept a patch if you want to
|
|
write something up!). For more information about LLVM, check out:
|
|
|
|
* `LLVM homepage <https://llvm.org/>`_
|
|
* `LLVM doxygen tree <https://llvm.org/doxygen/>`_
|
|
* Additional information about the LLVM directory structure and tool chain
|
|
can be found on the main :doc:`GettingStarted` page.
|
|
* If you are having problems building or using LLVM, or if you have any other
|
|
general questions about LLVM, please consult the
|
|
:doc:`Frequently Asked Questions <FAQ>` page.
|