Re-structured and updated the documentation.

docs/BuildingLLVM.md

@@ -0,0 +1,71 @@
+# Compiling LLVM and Clang from source
+
+This document explains how to build LLVM and Clang from source code.
+
+It's a process only recommended for developers that need to make changes to LLVM or Clang, or
+build the binary packages needed for the CI system.
+
+Git repository URLs found here: [http://llvm.org/docs/GettingStarted.html#git-mirror]
+(http://llvm.org/docs/GettingStarted.html#git-mirror)
+
+1. Clone LLVM to `<CppSharp>\deps\llvm`
+2. Clone Clang to `<CppSharp>\deps\llvm\tools\clang`
+
+Required LLVM/Clang commits:
+
+[LLVM: see /build/LLVM-commit.](https://github.com/mono/CppSharp/tree/master/build/LLVM-commit)
+
+[Clang: see /build/Clang-commit.](https://github.com/mono/CppSharp/tree/master/build/Clang-commit)
+
+## Compiling on Windows/Visual Studio
+
+```shell
+cd <CppSharp>\deps\llvm\build
+
+cmake -G "Visual Studio 12" -DCLANG_BUILD_EXAMPLES=false -DCLANG_INCLUDE_DOCS=false -DCLANG_INCLUDE_TESTS=false -DCLANG_INCLUDE_DOCS=false -DCLANG_BUILD_EXAMPLES=false -DLLVM_TARGETS_TO_BUILD="X86" -DLLVM_INCLUDE_EXAMPLES=false -DLLVM_INCLUDE_DOCS=false -DLLVM_INCLUDE_TESTS=false ..
+
+msbuild LLVM.sln /p:Configuration=RelWithDebInfo;Platform=Win32 /m
+```
+
+Or, if you need 64-bit binaries:
+
+```shell
+cd <CppSharp>\deps\llvm\build
+
+cmake -G "Visual Studio 12 Win64" -DCLANG_BUILD_EXAMPLES=false -DCLANG_INCLUDE_DOCS=false -DCLANG_INCLUDE_TESTS=false -DCLANG_INCLUDE_DOCS=false -DCLANG_BUILD_EXAMPLES=false -DLLVM_TARGETS_TO_BUILD="X86" -DLLVM_INCLUDE_EXAMPLES=false -DLLVM_INCLUDE_DOCS=false -DLLVM_INCLUDE_TESTS=false ..
+
+msbuild LLVM.sln /p:Configuration=RelWithDebInfo;Platform=x64 /m
+```
+
+## Compiling on Mac OS X
+
+1. Compile LLVM solution in *RelWithDebInfo* mode
+   The following CMake variables should be enabled:
+    - LLVM_ENABLE_LIBCXX (enables libc++ standard library support)
+    - LLVM_BUILD_32_BITS for 32-bit builds (defaults to 64-bit)
+
+```shell
+mkdir -p deps/llvm/build && cd deps/llvm/build
+
+cmake -G "Unix Makefiles" -DLLVM_ENABLE_LIBCXX=true -DLLVM_BUILD_32_BITS=true -DCMAKE_BUILD_TYPE=RelWithDebInfo ..
+
+make
+```
+
+## Compiling on Linux
+
+If you do not have native build tools you can install them first with:
+
+```shell
+sudo apt-get install cmake ninja-build build-essential
+```
+
+And then build LLVM with:
+
+```shell
+cd deps/llvm/build
+
+cmake -G Ninja -DCLANG_BUILD_EXAMPLES=false -DCLANG_INCLUDE_DOCS=false -DCLANG_INCLUDE_TESTS=false -DCLANG_INCLUDE_DOCS=false -DCLANG_BUILD_EXAMPLES=false -DLLVM_TARGETS_TO_BUILD="X86" -DLLVM_INCLUDE_EXAMPLES=false -DLLVM_INCLUDE_DOCS=false -DLLVM_INCLUDE_TESTS=false ..
+
+ninja
+```