llvm 12.0.0

- deparallelize ARM build to avoid build failures.
- remove patches that no longer apply
- explicitly specify install rpath, as this is no longer specified in
  the build

Formula/llvm.rb

@@ -1,44 +1,12 @@
 class Llvm < Formula
   desc "Next-gen compiler infrastructure"
   homepage "https://llvm.org/"
+  url "https://github.com/llvm/llvm-project/releases/download/llvmorg-12.0.0/llvm-project-12.0.0.src.tar.xz"
+  sha256 "9ed1688943a4402d7c904cc4515798cdb20080066efa010fe7e1f2551b423628"
   # The LLVM Project is under the Apache License v2.0 with LLVM Exceptions
   license "Apache-2.0" => { with: "LLVM-exception" }
-  revision 1
   head "https://github.com/llvm/llvm-project.git", branch: "main"
 
-  stable do
-    url "https://github.com/llvm/llvm-project/releases/download/llvmorg-11.1.0/llvm-project-11.1.0.src.tar.xz"
-    sha256 "74d2529159fd118c3eac6f90107b5611bccc6f647fdea104024183e8d5e25831"
-
-    patch do
-      url "https://github.com/llvm/llvm-project/commit/c86f56e32e724c6018e579bb2bc11e667c96fc96.patch?full_index=1"
-      sha256 "6e13e01b4f9037bb6f43f96cb752d23b367fe7db4b66d9bf2a4aeab9234b740a"
-    end
-
-    patch do
-      url "https://github.com/llvm/llvm-project/commit/31e5f7120bdd2f76337686d9d169b1c00e6ee69c.patch?full_index=1"
-      sha256 "f025110aa6bf80bd46d64a0e2b1e2064d165353cd7893bef570b6afba7e90b4d"
-    end
-
-    patch do
-      url "https://github.com/llvm/llvm-project/commit/3c7bfbd6831b2144229734892182d403e46d7baf.patch?full_index=1"
-      sha256 "62014ddad6d5c485ecedafe3277fe7978f3f61c940976e3e642536726abaeb68"
-    end
-
-    patch do
-      url "https://github.com/llvm/llvm-project/commit/c4d7536136b331bada079b2afbb2bd09ad8296bf.patch?full_index=1"
-      sha256 "2b894cbaf990510969bf149697882c86a068a1d704e749afa5d7b71b6ee2eb9f"
-    end
-
-    # Upstream ARM patch for OpenMP runtime, remove in next version
-    # https://reviews.llvm.org/D91002
-    # https://bugs.llvm.org/show_bug.cgi?id=47609
-    patch do
-      url "https://raw.githubusercontent.com/Homebrew/formula-patches/6166a68c/llvm/openmp_arm.patch"
-      sha256 "70fe3836b423e593688cd1cc7a3d76ee6406e64b9909f1a2f780c6f018f89b1e"
-    end
-  end
-
   livecheck do
     url :homepage
     regex(/LLVM (\d+\.\d+\.\d+)/i)
@@ -66,10 +34,10 @@ class Llvm < Formula
   # See: Homebrew/homebrew-core/issues/35513
   depends_on "cmake" => :build
   depends_on "swig" => :build
-  depends_on "libffi"
   depends_on "python@3.9"
 
   uses_from_macos "libedit"
+  uses_from_macos "libffi", since: :catalina
   uses_from_macos "libxml2"
   uses_from_macos "ncurses"
   uses_from_macos "zlib"
@@ -128,8 +96,6 @@ class Llvm < Formula
       -DLLVM_ENABLE_Z3_SOLVER=OFF
       -DLLVM_OPTIMIZED_TABLEGEN=ON
       -DLLVM_TARGETS_TO_BUILD=all
-      -DFFI_INCLUDE_DIR=#{Formula["libffi"].opt_lib}/libffi-#{Formula["libffi"].version}/include
-      -DFFI_LIBRARY_DIR=#{Formula["libffi"].opt_lib}
       -DLLDB_USE_SYSTEM_DEBUGSERVER=ON
       -DLLDB_ENABLE_PYTHON=ON
       -DLLDB_ENABLE_LUA=OFF
@@ -139,19 +105,22 @@ class Llvm < Formula
       -DCLANG_PYTHON_BINDINGS_VERSIONS=#{py_ver}
     ]
 
+    if MacOS.version >= :catalina
+      args << "-DFFI_INCLUDE_DIR=#{MacOS.sdk_path}/usr/include/ffi"
+      args << "-DFFI_LIBRARY_DIR=#{MacOS.sdk_path}/usr/lib"
+    else
+      args << "-DFFI_INCLUDE_DIR=#{Formula["libffi"].opt_include}"
+      args << "-DFFI_LIBRARY_DIR=#{Formula["libffi"].opt_lib}"
+    end
+
     on_macos do
       args << "-DLLVM_BUILD_LLVM_C_DYLIB=ON"
       args << "-DLLVM_ENABLE_LIBCXX=ON"
       args << "-DLLVM_CREATE_XCODE_TOOLCHAIN=#{MacOS::Xcode.installed? ? "ON" : "OFF"}"
+      args << "-DRUNTIMES_CMAKE_ARGS=-DCMAKE_INSTALL_RPATH=@loader_path/../lib"
 
       sdk = MacOS.sdk_path_if_needed
       args << "-DDEFAULT_SYSROOT=#{sdk}" if sdk
-
-      if MacOS.version == :mojave && MacOS::CLT.installed?
-        # Mojave CLT linker via software update is older than Xcode.
-        # Use it to retain compatibility.
-        args << "-DCMAKE_LINKER=/Library/Developer/CommandLineTools/usr/bin/ld"
-      end
     end
 
     on_linux do
@@ -165,6 +134,8 @@ class Llvm < Formula
     llvmpath = buildpath/"llvm"
     mkdir llvmpath/"build" do
       system "cmake", "-G", "Unix Makefiles", "..", *(std_cmake_args + args)
+      # Workaround for CMake Error: failed to create symbolic link
+      ENV.deparallelize if Hardware::CPU.arm?
       system "cmake", "--build", "."
       system "cmake", "--build", ".", "--target", "install"
       system "cmake", "--build", ".", "--target", "install-xcode-toolchain" if MacOS::Xcode.installed?