class LlvmAT39 < Formula
  desc "Next-gen compiler infrastructure"
  homepage "https://llvm.org/"
  url "https://releases.llvm.org/3.9.1/llvm-3.9.1.src.tar.xz"
  sha256 "1fd90354b9cf19232e8f168faf2220e79be555df3aa743242700879e8fd329ee"
  revision 2

  bottle do
    cellar :any
    rebuild 1
    sha256 "0a9b15fb4f4633f7758671d0ced83b54333b58229a2b24905aa7d5f4fe49cfd9" => :mojave
    sha256 "341efc104ef59aa23177e257615cef092ec8f67845b7235a87e8ad1ae210b53c" => :high_sierra
    sha256 "621531bbbc72bb0ffe01e25b3cc6beb2f51f9738aafa6ee52ecc9b3296ba0db3" => :sierra
  end

  keg_only :versioned_formula

  depends_on "cmake" => :build
  depends_on "libffi"

  resource "clang" do
    url "https://releases.llvm.org/3.9.1/cfe-3.9.1.src.tar.xz"
    sha256 "e6c4cebb96dee827fa0470af313dff265af391cb6da8d429842ef208c8f25e63"
  end

  resource "clang-extra-tools" do
    url "https://releases.llvm.org/3.9.1/clang-tools-extra-3.9.1.src.tar.xz"
    sha256 "29a5b65bdeff7767782d4427c7c64d54c3a8684bc6b217b74a70e575e4813635"
  end

  resource "compiler-rt" do
    url "https://releases.llvm.org/3.9.1/compiler-rt-3.9.1.src.tar.xz"
    sha256 "d30967b1a5fa51a2503474aacc913e69fd05ae862d37bf310088955bdb13ec99"
  end

  resource "libcxx" do
    url "https://releases.llvm.org/3.9.1/libcxx-3.9.1.src.tar.xz"
    sha256 "25e615e428f60e651ed09ffd79e563864e3f4bc69a9e93ee41505c419d1a7461"
  end

  resource "libunwind" do
    url "https://releases.llvm.org/3.9.1/libunwind-3.9.1.src.tar.xz"
    sha256 "0b0bc73264d7ab77d384f8a7498729e3c4da8ffee00e1c85ad02a2f85e91f0e6"
  end

  resource "lld" do
    url "https://releases.llvm.org/3.9.1/lld-3.9.1.src.tar.xz"
    sha256 "48e128fabb2ddaee64ecb8935f7ac315b6e68106bc48aeaf655d179c65d87f34"
  end

  resource "lldb" do
    url "https://releases.llvm.org/3.9.1/lldb-3.9.1.src.tar.xz"
    sha256 "7e3311b2a1f80f4d3426e09f9459d079cab4d698258667e50a46dccbaaa460fc"
  end

  resource "openmp" do
    url "https://releases.llvm.org/3.9.1/openmp-3.9.1.src.tar.xz"
    sha256 "d23b324e422c0d5f3d64bae5f550ff1132c37a070e43c7ca93991676c86c7766"
  end

  resource "polly" do
    url "https://releases.llvm.org/3.9.1/polly-3.9.1.src.tar.xz"
    sha256 "9ba5e61fc7bf8c7435f64e2629e0810c9b1d1b03aa5b5605b780d0e177b4cb46"
  end

  def install
    # Apple's libstdc++ is too old to build LLVM
    ENV.libcxx if ENV.compiler == :clang

    (buildpath/"tools/clang").install resource("clang")
    (buildpath/"tools/clang/tools/extra").install resource("clang-extra-tools")
    (buildpath/"projects/openmp").install resource("openmp")
    (buildpath/"projects/libcxx").install resource("libcxx")
    (buildpath/"projects/libunwind").install resource("libunwind")
    (buildpath/"tools/lld").install resource("lld")
    (buildpath/"tools/polly").install resource("polly")
    (buildpath/"projects/compiler-rt").install resource("compiler-rt")

    # compiler-rt has some iOS simulator features that require i386 symbols
    # I'm assuming the rest of clang needs support too for 32-bit compilation
    # to work correctly, but if not, perhaps universal binaries could be
    # limited to compiler-rt. llvm makes this somewhat easier because compiler-rt
    # can almost be treated as an entirely different build from llvm.
    ENV.permit_arch_flags

    args = %W[
      -DLIBOMP_ARCH=x86_64
      -DLINK_POLLY_INTO_TOOLS=ON
      -DLLVM_BUILD_EXTERNAL_COMPILER_RT=ON
      -DLLVM_BUILD_LLVM_DYLIB=ON
      -DLLVM_ENABLE_EH=ON
      -DLLVM_ENABLE_FFI=ON
      -DLLVM_ENABLE_LIBCXX=ON
      -DLLVM_ENABLE_RTTI=ON
      -DLLVM_INCLUDE_DOCS=OFF
      -DLLVM_INSTALL_UTILS=ON
      -DLLVM_OPTIMIZED_TABLEGEN=ON
      -DLLVM_TARGETS_TO_BUILD=all
      -DWITH_POLLY=ON
      -DFFI_INCLUDE_DIR=#{Formula["libffi"].opt_lib}/libffi-#{Formula["libffi"].version}/include
      -DFFI_LIBRARY_DIR=#{Formula["libffi"].opt_lib}
      -DLLVM_CREATE_XCODE_TOOLCHAIN=ON
    ]

    mkdir "build" do
      system "cmake", "-G", "Unix Makefiles", "..", *(std_cmake_args + args)
      system "make"
      system "make", "install"
      system "make", "install-xcode-toolchain"
    end

    (share/"clang/tools").install Dir["tools/clang/tools/scan-{build,view}"]

    # scan-build is in Perl, so the @ in our path needs to be escaped
    inreplace "#{share}/clang/tools/scan-build/bin/scan-build",
              "$RealBin/bin/clang", "#{bin}/clang".gsub("@", "\\@")

    bin.install_symlink share/"clang/tools/scan-build/bin/scan-build", share/"clang/tools/scan-view/bin/scan-view"
    man1.install_symlink share/"clang/tools/scan-build/man/scan-build.1"

    # install llvm python bindings
    (lib/"python2.7/site-packages").install buildpath/"bindings/python/llvm"
    (lib/"python2.7/site-packages").install buildpath/"tools/clang/bindings/python/clang"
  end

  def caveats; <<~EOS
    LLVM executables are installed in #{opt_bin}.
    Extra tools are installed in #{opt_pkgshare}.

    To use the bundled libc++ please add the following LDFLAGS:
      LDFLAGS="-L#{opt_lib} -Wl,-rpath,#{opt_lib}"
  EOS
  end

  test do
    assert_equal prefix.to_s, shell_output("#{bin}/llvm-config --prefix").chomp

    (testpath/"omptest.c").write <<~EOS
      #include <stdlib.h>
      #include <stdio.h>
      #include <omp.h>

      int main() {
          #pragma omp parallel num_threads(4)
          {
            printf("Hello from thread %d, nthreads %d\\n", omp_get_thread_num(), omp_get_num_threads());
          }
          return EXIT_SUCCESS;
      }
    EOS

    system "#{bin}/clang", "-L#{lib}", "-fopenmp", "-nobuiltininc",
                           "-I#{lib}/clang/#{version}/include",
                           "omptest.c", "-o", "omptest"
    testresult = shell_output("./omptest")

    sorted_testresult = testresult.split("\n").sort.join("\n")
    expected_result = <<~EOS
      Hello from thread 0, nthreads 4
      Hello from thread 1, nthreads 4
      Hello from thread 2, nthreads 4
      Hello from thread 3, nthreads 4
    EOS
    assert_equal expected_result.strip, sorted_testresult.strip

    (testpath/"test.c").write <<~EOS
      #include <stdio.h>

      int main()
      {
        printf("Hello World!\\n");
        return 0;
      }
    EOS

    (testpath/"test.cpp").write <<~EOS
      #include <iostream>

      int main()
      {
        std::cout << "Hello World!" << std::endl;
        return 0;
      }
    EOS

    # Testing Command Line Tools
    if MacOS::CLT.installed?
      libclangclt = Dir["/Library/Developer/CommandLineTools/usr/lib/clang/#{MacOS::CLT.version.to_i}*"].last { |f| File.directory? f }

      system "#{bin}/clang++", "-v", "-nostdinc",
              "-I/Library/Developer/CommandLineTools/usr/include/c++/v1",
              "-I#{libclangclt}/include",
              "-I/usr/include", # need it because /Library/.../usr/include/c++/v1/iosfwd refers to <wchar.h>, which CLT installs to /usr/include
              "test.cpp", "-o", "testCLT++"
      assert_includes MachO::Tools.dylibs("testCLT++"), "/usr/lib/libc++.1.dylib"
      assert_equal "Hello World!", shell_output("./testCLT++").chomp

      system "#{bin}/clang", "-v", "-nostdinc",
              "-I/usr/include", # this is where CLT installs stdio.h
              "test.c", "-o", "testCLT"
      assert_equal "Hello World!", shell_output("./testCLT").chomp
    end

    # Testing Xcode
    if MacOS::Xcode.installed?
      libclangxc = Dir["#{MacOS::Xcode.toolchain_path}/usr/lib/clang/#{DevelopmentTools.clang_version}*"].last { |f| File.directory? f }

      system "#{bin}/clang++", "-v", "-nostdinc",
              "-I#{MacOS::Xcode.toolchain_path}/usr/include/c++/v1",
              "-I#{libclangxc}/include",
              "-I#{MacOS.sdk_path}/usr/include",
              "test.cpp", "-o", "testXC++"
      assert_includes MachO::Tools.dylibs("testXC++"), "/usr/lib/libc++.1.dylib"
      assert_equal "Hello World!", shell_output("./testXC++").chomp

      system "#{bin}/clang", "-v", "-nostdinc",
              "-I#{MacOS.sdk_path}/usr/include",
              "test.c", "-o", "testXC"
      assert_equal "Hello World!", shell_output("./testXC").chomp
    end

    # link against installed libc++
    # related to https://github.com/Homebrew/legacy-homebrew/issues/47149
    system "#{bin}/clang++", "-v", "-nostdinc",
            "-std=c++11", "-stdlib=libc++",
            "-I#{MacOS::Xcode.toolchain_path}/usr/include/c++/v1",
            "-I#{libclangxc}/include",
            "-I#{MacOS.sdk_path}/usr/include",
            "-L#{lib}",
            "-Wl,-rpath,#{lib}", "test.cpp", "-o", "test"
    assert_includes MachO::Tools.dylibs("test"), "#{opt_lib}/libc++.1.dylib"
    assert_equal "Hello World!", shell_output("./test").chomp
  end
end