class Llvm < Formula
  desc "Next-gen compiler infrastructure"
  homepage "https://llvm.org/"

  stable do
    url "https://github.com/llvm/llvm-project/releases/download/llvmorg-8.0.1/llvm-8.0.1.src.tar.xz"
    sha256 "44787a6d02f7140f145e2250d56c9f849334e11f9ae379827510ed72f12b75e7"

    resource "clang" do
      url "https://github.com/llvm/llvm-project/releases/download/llvmorg-8.0.1/cfe-8.0.1.src.tar.xz"
      sha256 "70effd69f7a8ab249f66b0a68aba8b08af52aa2ab710dfb8a0fba102685b1646"
    end

    resource "clang-extra-tools" do
      url "https://github.com/llvm/llvm-project/releases/download/llvmorg-8.0.1/clang-tools-extra-8.0.1.src.tar.xz"
      sha256 "187179b617e4f07bb605cc215da0527e64990b4a7dd5cbcc452a16b64e02c3e1"
    end

    resource "compiler-rt" do
      url "https://github.com/llvm/llvm-project/releases/download/llvmorg-8.0.1/compiler-rt-8.0.1.src.tar.xz"
      sha256 "11828fb4823387d820c6715b25f6b2405e60837d12a7469e7a8882911c721837"
    end

    resource "libcxx" do
      url "https://github.com/llvm/llvm-project/releases/download/llvmorg-8.0.1/libcxx-8.0.1.src.tar.xz"
      sha256 "7f0652c86a0307a250b5741ab6e82bb10766fb6f2b5a5602a63f30337e629b78"
    end

    resource "libunwind" do
      url "https://github.com/llvm/llvm-project/releases/download/llvmorg-8.0.1/libunwind-8.0.1.src.tar.xz"
      sha256 "1870161dda3172c63e632c1f60624564e1eb0f9233cfa8f040748ca5ff630f6e"
    end

    resource "lld" do
      url "https://github.com/llvm/llvm-project/releases/download/llvmorg-8.0.1/lld-8.0.1.src.tar.xz"
      sha256 "9fba1e94249bd7913e8a6c3aadcb308b76c8c3d83c5ce36c99c3f34d73873d88"
    end

    resource "lldb" do
      url "https://github.com/llvm/llvm-project/releases/download/llvmorg-8.0.1/lldb-8.0.1.src.tar.xz"
      sha256 "e8a79baa6d11dd0650ab4a1b479f699dfad82af627cbbcd49fa6f2dc14e131d7"
    end

    resource "openmp" do
      url "https://github.com/llvm/llvm-project/releases/download/llvmorg-8.0.1/openmp-8.0.1.src.tar.xz"
      sha256 "3e85dd3cad41117b7c89a41de72f2e6aa756ea7b4ef63bb10dcddf8561a7722c"
    end

    resource "polly" do
      url "https://github.com/llvm/llvm-project/releases/download/llvmorg-8.0.1/polly-8.0.1.src.tar.xz"
      sha256 "e8a1f7e8af238b32ce39ab5de1f3317a2e3f7d71a8b1b8bbacbd481ac76fd2d1"
    end
  end

  bottle do
    cellar :any
    sha256 "8017a53698fb2daf1ee34842baf27fe205ccf24292bd5a3afe4af9654aab29f2" => :mojave
    sha256 "ebe23525722afbd8b06744e9ad021cb9cd41ad3167c5fd3c4ea18e2c69767481" => :high_sierra
    sha256 "f1046344d20c85c40554e9378a4f3aaab2c2c6ceb707e0201462c2fd56fe05be" => :sierra
  end

  # Clang cannot find system headers if Xcode CLT is not installed
  pour_bottle? do
    reason "The bottle needs the Xcode CLT to be installed."
    satisfy { MacOS::CLT.installed? }
  end

  head do
    url "https://git.llvm.org/git/llvm.git"

    resource "clang" do
      url "https://git.llvm.org/git/clang.git"
    end

    resource "clang-extra-tools" do
      url "https://git.llvm.org/git/clang-tools-extra.git"
    end

    resource "compiler-rt" do
      url "https://git.llvm.org/git/compiler-rt.git"
    end

    resource "libcxx" do
      url "https://git.llvm.org/git/libcxx.git"
    end

    resource "libunwind" do
      url "https://git.llvm.org/git/libunwind.git"
    end

    resource "lld" do
      url "https://git.llvm.org/git/lld.git"
    end

    resource "lldb" do
      url "https://git.llvm.org/git/lldb.git"
    end

    resource "openmp" do
      url "https://git.llvm.org/git/openmp.git"
    end

    resource "polly" do
      url "https://git.llvm.org/git/polly.git"
    end
  end

  keg_only :provided_by_macos

  # https://llvm.org/docs/GettingStarted.html#requirement
  depends_on "cmake" => :build
  depends_on :xcode => :build
  depends_on "libffi"
  depends_on "swig" if MacOS.version >= :lion

  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/lldb").install resource("lldb")
    (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
      -DLLDB_USE_SYSTEM_DEBUGSERVER=ON
      -DLLDB_DISABLE_PYTHON=1
      -DLIBOMP_INSTALL_ALIASES=OFF
    ]

    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}"]
    (share/"cmake").install "cmake/modules"
    inreplace "#{share}/clang/tools/scan-build/bin/scan-build", "$RealBin/bin/clang", "#{bin}/clang"
    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
    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

    clean_version = version.to_s[/(\d+\.?)+/]

    system "#{bin}/clang", "-L#{lib}", "-fopenmp", "-nobuiltininc",
                           "-I#{lib}/clang/#{clean_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