Cannot build LLVM on Windows 10 using Visual Studio 2015 - c++

Question

I'm trying to install LLVM on Windows 10 using Visual Studio, using the guide http://llvm.org/docs/GettingStartedVS.html, but I'm getting errors:
Here is my view in CMake GUI, where I've directed it to use the C++ compiler C:/Program Files (x86)/Microsoft Visual Studio 14.0/VC/bin/cl.exe.
I've already created a new directory called llvm for the build, since I cannot build in the source directory.
What am I doing wrong?
The configure process displays the following output:
The C compiler identification is unknown
The CXX compiler identification is unknown
The ASM compiler identification is MSVC
Found assembler: C:/Program Files (x86)/Microsoft Visual Studio 14.0/VC/bin/cl.exe
CMake Error at CMakeLists.txt:48 (project):
No CMAKE_C_COMPILER could be found.
Check for working CXX compiler: C:/Program Files (x86)/Microsoft Visual Studio 14.0/VC/bin/cl.exe
CMake Error: Generator: execution of make failed. Make command was: "MSBuild.exe" "cmTC_c88f4.vcxproj" "/p:Configuration=Debug" "/p:VisualStudioVersion=15.0"
Check for working CXX compiler: C:/Program Files (x86)/Microsoft Visual Studio 14.0/VC/bin/cl.exe -- broken
CMake Error at C:/Program Files/CMake/share/cmake-3.7/Modules/CMakeTestCXXCompiler.cmake:44 (message):
The C++ compiler "C:/Program Files (x86)/Microsoft Visual Studio
14.0/VC/bin/cl.exe" is not able to compile a simple test program.
It fails with the following output:
Change Dir: C:/dev/llvm/CMakeFiles/CMakeTmp
Run Build Command:"MSBuild.exe" "cmTC_c88f4.vcxproj"
"/p:Configuration=Debug" "/p:VisualStudioVersion=15.0"
Generator: execution of make failed. Make command was: "MSBuild.exe"
"cmTC_c88f4.vcxproj" "/p:Configuration=Debug" "/p:VisualStudioVersion=15.0"
CMake will not be able to correctly generate this project.
Call Stack (most recent call first):
CMakeLists.txt:48 (project)
Configuring incomplete, errors occurred!
See also "C:/dev/llvm/CMakeFiles/CMakeOutput.log".
See also "C:/dev/llvm/CMakeFiles/CMakeError.log".

Answer 1

I am working with your same setup(exception being Windows 32-bit), the LLVM version I have chosen is 4.0.0. I followed the tutorial for setting it up with clang.
I made notes for my entire process.
Instructions for building LLVM 4.0.0 from source:
Create a folder named LLVM in any suitable location.
cd LLVM
svn co http://llvm.org/svn/llvm-project/llvm/trunk llvm
cd llvm\tools
svn co http://llvm.org/svn/llvm-project/cfe/trunk clang
cd .... # going back to where you started
mkdir build
cd build
cmake -G "Visual Studio 14" ..\llvm ##depends on the version of VS you use, I used VS 2015 -> VISUAL STUDIO 14.0
If successful, in the build directory you will find LLVM.sln file which can be opened in Visual Studio, once opened, you can navigate through the solution explorer and right click the ALL_BUILD project -> Build.
Notes:
I'm using Visual Studio 2015 (Update 3)
I'm using Windows 10 32-bit system
Header files dependencies can be fixed by appending paths to the files where it can be found in the Visual Studio 14.0 folder in Program Files.
My environment variables for reference:
**INCLUDE=C:\Program Files\Microsoft Visual Studio 14.0\VC\INCLUDE;C:\Program Files\Microsoft Visual Studio 14.0\VC\ATLMFC\INCLUDE;C:\Program Files\Windows Kits\10\include\10.0.10240.0\ucrt;C:\Program Files\Windows Kits\NETFXSDK\4.6.1\include\um;C:\Program Files\Windows Kits\8.1\include\shared;C:\Program Files\Windows Kits\8.1\include\um;C:\Program Files\Windows Kits\8.1\include\winrt;
**LIBPATH=C:\Windows\Microsoft.NET\Framework\v4.0.30319;C:\Program Files\Microsoft Visual Studio 14.0\VC\LIB;C:\Program Files\Microsoft Visual Studio 14.0\VC\ATLMFC\LIB;C:\Program Files\Windows Kits\8.1\References\CommonConfiguration\Neutral;\Microsoft.VCLibs\14.0\References\CommonConfiguration\neutral;
Set the PATH enviroment variable for llvm tools like clang, llc, lli, etc., if they're not recognized on developer command prompt.
You may also find executables like clang and clang++ missing from the build when downloading from the github. I copied these from the prebuilt binaries which I had downloaded for windows which can be found on the LLVM releases page.
Hope this helps!