[CMake][Fuchsia] Support for building on Windows

[phosek]

Summary

This change adds the necessary flags for building the full Fuchsia
toolchain on Windows.

clang/cmake/caches/Fuchsia-stage2.cmake

 set(LLVM_ENABLE_TERMINFO OFF CACHE BOOL "")
 set(LLVM_ENABLE_UNWIND_TABLES OFF CACHE BOOL "")
 set(LLVM_ENABLE_ZLIB ON CACHE BOOL "")
 set(LLVM_INCLUDE_DOCS OFF CACHE BOOL "")
 set(LLVM_INCLUDE_EXAMPLES OFF CACHE BOOL "")
 set(LLVM_INCLUDE_GO_TESTS OFF CACHE BOOL "")
 set(LLVM_USE_RELATIVE_PATHS_IN_DEBUG_INFO ON CACHE BOOL "")
 
+if(WIN32 AND NOT MINGW)
+  set(LLVM_USE_CRT_RELEASE "MT" CACHE STRING "")
+endif()
+
 set(CLANG_DEFAULT_CXX_STDLIB libc++ CACHE STRING "")
 if(NOT APPLE)
   set(CLANG_DEFAULT_LINKER lld CACHE STRING "")
   set(CLANG_DEFAULT_OBJCOPY llvm-objcopy CACHE STRING "")
 endif()
 set(CLANG_DEFAULT_RTLIB compiler-rt CACHE STRING "")
 set(CLANG_SPAWN_CC1 ON CACHE BOOL "")
 set(CLANG_ENABLE_ARCMT OFF CACHE BOOL "")
 set(CLANG_ENABLE_STATIC_ANALYZER ON CACHE BOOL "")
 set(CLANG_PLUGIN_SUPPORT OFF CACHE BOOL "")
 
 set(ENABLE_EXPERIMENTAL_NEW_PASS_MANAGER ON CACHE BOOL "")
 set(ENABLE_LINKER_BUILD_ID ON CACHE BOOL "")
 set(ENABLE_X86_RELAX_RELOCATIONS ON CACHE BOOL "")
 
 set(CMAKE_BUILD_TYPE Release CACHE STRING "")
 if (APPLE)
   set(MACOSX_DEPLOYMENT_TARGET 10.7 CACHE STRING "")
+elseif(WIN32 AND NOT MINGW)
+  set(CMAKE_MSVC_RUNTIME_LIBRARY "MultiThreaded" CACHE STRING "")
 endif()
 
 if(APPLE)
   list(APPEND BUILTIN_TARGETS "default")
   list(APPEND RUNTIME_TARGETS "default")
 
   set(COMPILER_RT_ENABLE_TVOS OFF CACHE BOOL "")
   set(COMPILER_RT_ENABLE_WATCHOS OFF CACHE BOOL "")
if(APPLE)
   set(LIBCXX_USE_COMPILER_RT ON CACHE BOOL "")
   set(LIBCXX_ENABLE_SHARED OFF CACHE BOOL "")
   set(LIBCXX_ENABLE_STATIC_ABI_LIBRARY ON CACHE BOOL "")
   set(LIBCXX_ABI_VERSION 2 CACHE STRING "")
   set(DARWIN_ios_ARCHS armv7;armv7s;arm64 CACHE STRING "")
   set(DARWIN_iossim_ARCHS i386;x86_64 CACHE STRING "")
   set(DARWIN_osx_ARCHS x86_64 CACHE STRING "")
   set(SANITIZER_MIN_OSX_VERSION 10.7 CACHE STRING "")
+elseif(WIN32 AND NOT MINGW)
+  list(APPEND BUILTIN_TARGETS "default")
+  list(APPEND RUNTIME_TARGETS "default")
+
+  set(LIBCXX_HAS_WIN32_THREAD_API ON CACHE BOOL "")
+  set(LIBCXX_ENABLE_MONOTONIC_CLOCK ON CACHE BOOL "")
+  set(LIBCXX_SUPPORTS_STD_EQ_CXX11_FLAG ON CACHE BOOL "")
+  set(LIBCXX_HAVE_CXX_ATOMICS_WITHOUT_LIB ON CACHE BOOL "")
+  set(LIBCXX_ENABLE_EXPERIMENTAL_LIBRARY OFF CACHE BOOL "")
+  set(LIBCXX_ENABLE_FILESYSTEM OFF CACHE BOOL "")
+  set(LIBCXX_ENABLE_ABI_LINKER_SCRIPT OFF CACHE BOOL "")
 endif()
 
 foreach(target aarch64-unknown-linux-gnu;armv7-unknown-linux-gnueabihf;i386-unknown-linux-gnu;x86_64-unknown-linux-gnu)
   if(LINUX_${target}_SYSROOT)
     # Set the per-target builtins options.
     list(APPEND BUILTIN_TARGETS "${target}")
     set(BUILTINS_${target}_CMAKE_SYSTEM_NAME Linux CACHE STRING "")
     set(BUILTINS_${target}_CMAKE_BUILD_TYPE RelWithDebInfo CACHE STRING "")
+    set(BUILTINS_${target}_CMAKE_C_FLAGS "--target=${target}" CACHE STRING "")
+    set(BUILTINS_${target}_CMAKE_CXX_FLAGS "--target=${target}" CACHE STRING "")
+    set(BUILTINS_${target}_CMAKE_ASM_FLAGS "--target=${target}" CACHE STRING "")
     set(BUILTINS_${target}_CMAKE_SYSROOT ${LINUX_${target}_SYSROOT} CACHE STRING "")
     set(BUILTINS_${target}_CMAKE_SHARED_LINKER_FLAGS "-fuse-ld=lld" CACHE STRING "")
     set(BUILTINS_${target}_CMAKE_MODULE_LINKER_FLAGS "-fuse-ld=lld" CACHE STRING "")
     set(BUILTINS_${target}_CMAKE_EXE_LINKER_FLAG "-fuse-ld=lld" CACHE STRING "")
 
     # Set the per-target runtimes options.
     list(APPEND RUNTIME_TARGETS "${target}")
     set(RUNTIMES_${target}_CMAKE_SYSTEM_NAME Linux CACHE STRING "")
     set(RUNTIMES_${target}_CMAKE_BUILD_TYPE RelWithDebInfo CACHE STRING "")
+    set(RUNTIMES_${target}_CMAKE_C_FLAGS "--target=${target}" CACHE STRING "")
+    set(RUNTIMES_${target}_CMAKE_CXX_FLAGS "--target=${target}" CACHE STRING "")
+    set(RUNTIMES_${target}_CMAKE_ASM_FLAGS "--target=${target}" CACHE STRING "")
     set(RUNTIMES_${target}_CMAKE_SYSROOT ${LINUX_${target}_SYSROOT} CACHE STRING "")
     set(RUNTIMES_${target}_CMAKE_SHARED_LINKER_FLAGS "-fuse-ld=lld" CACHE STRING "")
     set(RUNTIMES_${target}_CMAKE_MODULE_LINKER_FLAGS "-fuse-ld=lld" CACHE STRING "")
     set(RUNTIMES_${target}_CMAKE_EXE_LINKER_FLAGS "-fuse-ld=lld" CACHE STRING "")
     set(RUNTIMES_${target}_LLVM_ENABLE_ASSERTIONS ON CACHE BOOL "")
     set(RUNTIMES_${target}_LIBUNWIND_ENABLE_SHARED OFF CACHE BOOL "")
     set(RUNTIMES_${target}_LIBUNWIND_USE_COMPILER_RT ON CACHE BOOL "")
     set(RUNTIMES_${target}_LIBUNWIND_INSTALL_LIBRARY OFF CACHE BOOL "")
foreach(target aarch64-unknown-linux-gnu;armv7-unknown-linux-gnueabihf;i386-unknown-linux-gnu;x86_64-unknown-linux-gnu)
   endif()
 endforeach()
 
 if(FUCHSIA_SDK)
   set(FUCHSIA_aarch64_NAME arm64)
   set(FUCHSIA_x86_64_NAME x64)
   set(FUCHSIA_riscv64_NAME riscv64)
   foreach(target x86_64;aarch64;riscv64)
-    set(FUCHSIA_${target}_COMPILER_FLAGS "-I${FUCHSIA_SDK}/pkg/fdio/include")
+    set(FUCHSIA_${target}_COMPILER_FLAGS "--target=${target}-unknown-fuchsia -I${FUCHSIA_SDK}/pkg/fdio/include")
     set(FUCHSIA_${target}_LINKER_FLAGS "-L${FUCHSIA_SDK}/arch/${FUCHSIA_${target}_NAME}/lib")
     set(FUCHSIA_${target}_SYSROOT "${FUCHSIA_SDK}/arch/${FUCHSIA_${target}_NAME}/sysroot")
   endforeach()
 
   foreach(target x86_64;aarch64;riscv64)
     # Set the per-target builtins options.
     list(APPEND BUILTIN_TARGETS "${target}-unknown-fuchsia")
     set(BUILTINS_${target}-unknown-fuchsia_CMAKE_SYSTEM_NAME Fuchsia CACHE STRING "")

clang/cmake/caches/Fuchsia.cmake

 # This file sets up a CMakeCache for a Fuchsia toolchain build.
 
 set(LLVM_TARGETS_TO_BUILD X86;ARM;AArch64;RISCV CACHE STRING "")
 
 set(PACKAGE_VENDOR Fuchsia CACHE STRING "")
 
 set(LLVM_ENABLE_BACKTRACES OFF CACHE BOOL "")
 set(LLVM_ENABLE_PER_TARGET_RUNTIME_DIR ON CACHE BOOL "")
 set(LLVM_ENABLE_TERMINFO OFF CACHE BOOL "")
 set(LLVM_ENABLE_UNWIND_TABLES OFF CACHE BOOL "")
 set(LLVM_ENABLE_ZLIB OFF CACHE BOOL "")
 set(LLVM_INCLUDE_DOCS OFF CACHE BOOL "")
 set(LLVM_INCLUDE_EXAMPLES OFF CACHE BOOL "")
 set(LLVM_INCLUDE_GO_TESTS OFF CACHE BOOL "")
 
+if(WIN32 AND NOT MINGW)
+  set(LLVM_USE_CRT_RELEASE "MT" CACHE STRING "")
+endif()
+
 set(CLANG_DEFAULT_CXX_STDLIB libc++ CACHE STRING "")
 if(NOT APPLE)
   set(CLANG_DEFAULT_LINKER lld CACHE STRING "")
   set(CLANG_DEFAULT_OBJCOPY llvm-objcopy CACHE STRING "")
 endif()
 set(CLANG_DEFAULT_RTLIB compiler-rt CACHE STRING "")
 set(CLANG_ENABLE_ARCMT OFF CACHE BOOL "")
 set(CLANG_ENABLE_STATIC_ANALYZER ON CACHE BOOL "")
 set(CLANG_PLUGIN_SUPPORT OFF CACHE BOOL "")
 
 set(ENABLE_EXPERIMENTAL_NEW_PASS_MANAGER ON CACHE BOOL "")
 set(ENABLE_LINKER_BUILD_ID ON CACHE BOOL "")
 set(ENABLE_X86_RELAX_RELOCATIONS ON CACHE BOOL "")
 
 set(LLVM_ENABLE_ASSERTIONS ON CACHE BOOL "")
 set(CMAKE_BUILD_TYPE Release CACHE STRING "")
-if (APPLE)
+if(APPLE)
   set(MACOSX_DEPLOYMENT_TARGET 10.7 CACHE STRING "")
+elseif(WIN32 AND NOT MINGW)
+  set(CMAKE_MSVC_RUNTIME_LIBRARY "MultiThreaded" CACHE STRING "")
 endif()
 
 if(APPLE)
   set(COMPILER_RT_ENABLE_IOS OFF CACHE BOOL "")
   set(COMPILER_RT_ENABLE_TVOS OFF CACHE BOOL "")
   set(COMPILER_RT_ENABLE_WATCHOS OFF CACHE BOOL "")
 endif()
 
 set(LIBUNWIND_ENABLE_SHARED OFF CACHE BOOL "")
 set(LIBUNWIND_INSTALL_LIBRARY OFF CACHE BOOL "")
 set(LIBUNWIND_USE_COMPILER_RT ON CACHE BOOL "")
 set(LIBCXXABI_ENABLE_SHARED OFF CACHE BOOL "")
 set(LIBCXXABI_ENABLE_STATIC_UNWINDER ON CACHE BOOL "")
 set(LIBCXXABI_INSTALL_LIBRARY OFF CACHE BOOL "")
 set(LIBCXXABI_USE_COMPILER_RT ON CACHE BOOL "")
 set(LIBCXXABI_USE_LLVM_UNWINDER ON CACHE BOOL "")
 set(LIBCXX_ABI_VERSION 2 CACHE STRING "")
 set(LIBCXX_ENABLE_SHARED OFF CACHE BOOL "")
+if(WIN32 AND NOT MINGW)
+  set(LIBCXX_HAS_WIN32_THREAD_API ON CACHE BOOL "")
+  set(LIBCXX_ENABLE_MONOTONIC_CLOCK ON CACHE BOOL "")
+  set(LIBCXX_SUPPORTS_STD_EQ_CXX11_FLAG ON CACHE BOOL "")
+  set(LIBCXX_HAVE_CXX_ATOMICS_WITHOUT_LIB ON CACHE BOOL "")
+  set(LIBCXX_ENABLE_EXPERIMENTAL_LIBRARY OFF CACHE BOOL "")
+  set(LIBCXX_ENABLE_FILESYSTEM OFF CACHE BOOL "")
+  set(LIBCXX_ENABLE_ABI_LINKER_SCRIPT OFF CACHE BOOL "")
+else()
   set(LIBCXX_ENABLE_STATIC_ABI_LIBRARY ON CACHE BOOL "")
-set(LIBCXX_USE_COMPILER_RT ON CACHE BOOL "")
+endif()
 
 if(BOOTSTRAP_CMAKE_SYSTEM_NAME)
   set(target "${BOOTSTRAP_CMAKE_CXX_COMPILER_TARGET}")
   if(STAGE2_LINUX_${target}_SYSROOT)
     set(BUILTINS_${target}_CMAKE_SYSTEM_NAME Linux CACHE STRING "")
     set(BUILTINS_${target}_CMAKE_BUILD_TYPE Release CACHE STRING "")
     set(BUILTINS_${target}_CMAKE_SYSROOT ${STAGE2_LINUX_${target}_SYSROOT} CACHE STRING "")
     set(LLVM_BUILTIN_TARGETS "${target}" CACHE STRING "")