require "language/haskell"

class GhcAT82 < Formula
  include Language::Haskell::Cabal

  desc "Glorious Glasgow Haskell Compilation System"
  homepage "https://haskell.org/ghc/"
  url "https://downloads.haskell.org/~ghc/8.2.2/ghc-8.2.2-src.tar.xz"
  sha256 "bb8ec3634aa132d09faa270bbd604b82dfa61f04855655af6f9d14a9eedc05fc"

  bottle do
    sha256 "e7650911076879185c002c576337a642e07421618839fcc80ecf1481f2552675" => :mojave
    sha256 "3e712f2fd81912376f95e010b6612fd7214d84c0cf6f97ca47daafb0523f4b30" => :high_sierra
    sha256 "f079ae6408f3d27dcc407e0f6ed89e09a62d77b52e44e69d3df84494e99a37cc" => :sierra
    sha256 "d830f4b1f555c80f6de364e2d9a9defe8e62202415419ff9a6106dfff25ad5fb" => :el_capitan
  end

  keg_only :versioned_formula

  depends_on "python" => :build if build.bottle?
  depends_on "sphinx-doc" => :build
  depends_on :macos => :lion

  resource "gmp" do
    url "https://ftp.gnu.org/gnu/gmp/gmp-6.1.2.tar.xz"
    mirror "https://gmplib.org/download/gmp/gmp-6.1.2.tar.xz"
    mirror "https://ftpmirror.gnu.org/gmp/gmp-6.1.2.tar.xz"
    sha256 "87b565e89a9a684fe4ebeeddb8399dce2599f9c9049854ca8c0dfbdea0e21912"
  end

  if MacOS.version <= :lion
    fails_with :clang do
      cause <<~EOS
        Fails to bootstrap ghc-cabal. Error is:
          libraries/Cabal/Cabal/Distribution/Compat/Binary/Class.hs:398:14:
              The last statement in a 'do' block must be an expression
                n <- get :: Get Int getMany n
      EOS
    end
  end

  # https://www.haskell.org/ghc/download_ghc_8_0_1#macosx_x86_64
  # "This is a distribution for Mac OS X, 10.7 or later."
  resource "binary" do
    url "https://downloads.haskell.org/~ghc/8.2.2/ghc-8.2.2-x86_64-apple-darwin.tar.xz"
    sha256 "f90fcf62f7e0936a6dfc3601cf663729bfe9bbf85097d2d75f0a16f8c2e95c27"
  end

  resource "testsuite" do
    url "https://downloads.haskell.org/~ghc/8.2.2/ghc-8.2.2-testsuite.tar.xz"
    sha256 "927ff939f46a0f79aa87e16e56e0a024a288c78259bed874cb15aa96a653566c"
  end

  def install
    ENV["CC"] = ENV.cc
    ENV["LD"] = "ld"

    # Setting -march=native, which is what --build-from-source does, fails
    # on Skylake (and possibly other architectures as well) with the error
    # "Segmentation fault: 11" for at least the following files:
    #   utils/haddock/dist/build/Haddock/Backends/Hyperlinker/Types.dyn_o
    #   utils/haddock/dist/build/Documentation/Haddock/Types.dyn_o
    #   utils/haddock/dist/build/Haddock/GhcUtils.dyn_o
    #   utils/haddock/dist/build/Paths_haddock.dyn_o
    #   utils/haddock/dist/build/ResponseFile.dyn_o
    # Setting -march=core2 works around the bug.
    # Reported 22 May 2016: https://ghc.haskell.org/trac/ghc/ticket/12100
    # Note that `unless build.bottle?` avoids overriding --bottle-arch=[...].
    ENV["HOMEBREW_OPTFLAGS"] = "-march=#{Hardware.oldest_cpu}" unless build.bottle?

    # Build a static gmp rather than in-tree gmp, otherwise it links to brew's.
    gmp = libexec/"integer-gmp"

    # MPN_PATH: The lowest common denominator asm paths that work on Darwin,
    # corresponding to Yonah and Merom. Obviates --disable-assembly.
    ENV["MPN_PATH"] = "x86_64/fastsse x86_64/core2 x86_64 generic" if build.bottle?

    # GMP *does not* use PIC by default without shared libs  so --with-pic
    # is mandatory or else you'll get "illegal text relocs" errors.
    resource("gmp").stage do
      system "./configure", "--prefix=#{gmp}", "--with-pic", "--disable-shared"
      system "make"
      system "make", "check"
      ENV.deparallelize { system "make", "install" }
    end

    args = ["--with-gmp-includes=#{gmp}/include",
            "--with-gmp-libraries=#{gmp}/lib"]

    # As of Xcode 7.3 (and the corresponding CLT) `nm` is a symlink to `llvm-nm`
    # and the old `nm` is renamed `nm-classic`. Building with the new `nm`, a
    # segfault occurs with the following error:
    #   make[1]: * [compiler/stage2/dll-split.stamp] Segmentation fault: 11
    # Upstream is aware of the issue and is recommending the use of nm-classic
    # until Apple restores POSIX compliance:
    # https://ghc.haskell.org/trac/ghc/ticket/11744
    # https://ghc.haskell.org/trac/ghc/ticket/11823
    # https://mail.haskell.org/pipermail/ghc-devs/2016-April/011862.html
    # LLVM itself has already fixed the bug: llvm-mirror/llvm@ae7cf585
    # rdar://25311883 and rdar://25299678
    if DevelopmentTools.clang_build_version >= 703 && DevelopmentTools.clang_build_version < 800
      args << "--with-nm=#{`xcrun --find nm-classic`.chomp}"
    end

    resource("binary").stage do
      binary = buildpath/"binary"

      system "./configure", "--prefix=#{binary}", *args
      ENV.deparallelize { system "make", "install" }

      ENV.prepend_path "PATH", binary/"bin"
    end

    system "./configure", "--prefix=#{prefix}", *args
    system "make"

    if build.bottle?
      resource("testsuite").stage { buildpath.install Dir["*"] }
      cd "testsuite" do
        system "make", "clean"
        system "make", "CLEANUP=1", "THREADS=#{ENV.make_jobs}", "fast"
      end
    end

    ENV.deparallelize { system "make", "install" }
    Dir.glob(lib/"*/package.conf.d/package.cache") { |f| rm f }
  end

  def post_install
    system "#{bin}/ghc-pkg", "recache"
  end

  test do
    (testpath/"hello.hs").write('main = putStrLn "Hello Homebrew"')
    system "#{bin}/runghc", testpath/"hello.hs"
  end
end