Adding flang - a llvm based Fortran compiler (#5459)

* flang: initial commit

* flang: added symlink to clang's flang

* add flang wrapper

* flang wrapper: inject rpath as well

* flang wrapper: PATH -> -B

var/spack/repos/builtin/packages/flang/package.py

@@ -0,0 +1,80 @@
+##############################################################################
+# Copyright (c) 2017, Los Alamos National Security, LLC
+# Produced at the Los Alamos National Laboratory.
+#
+# This file is part of Spack.
+# Created by Todd Gamblin, tgamblin@llnl.gov, All rights reserved.
+# LLNL-CODE-647188
+#
+# For details, see https://github.com/llnl/spack
+# Please also see the NOTICE and LICENSE files for our notice and the LGPL.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License (as
+# published by the Free Software Foundation) version 2.1, February 1999.
+#
+# This program is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the IMPLIED WARRANTY OF
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the terms and
+# conditions of the GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public
+# License along with this program; if not, write to the Free Software
+# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+##############################################################################
+
+from spack import *
+import os
+
+
+class Flang(CMakePackage):
+    """Flang is a Fortran compiler targeting LLVM."""
+    homepage = "https://github.com/flang-compiler/flang"
+    url      = "https://github.com/flang-compiler/flang/flecsi/tarball/v1.0"
+
+    version('develop', git='https://github.com/flang-compiler/flang', branch='master')
+
+    depends_on(
+        "llvm+clang",
+        patches=patch('https://github.com/llvm-mirror/clang/pull/33.diff',
+                      sha256='e46d7ab305e5e95c51f4656d9b52058143cd85d859b312b3c80e93a02d54b4a5',
+                      when='@4.0.1', level=1, working_dir='tools/clang'))
+
+    def patch(self):
+        # Don't use -Werror
+        # https://github.com/flang-compiler/flang/pull/85
+        filter_file(r'-Werror', '', 'CMakeLists.txt')
+
+    def cmake_args(self):
+        options = [
+            '-DCMAKE_C_COMPILER=%s' % os.path.join(
+                self.spec['llvm'].prefix.bin, 'clang'),
+            '-DCMAKE_CXX_COMPILER=%s' % os.path.join(
+                self.spec['llvm'].prefix.bin, 'clang++'),
+            '-DCMAKE_Fortran_COMPILER=%s' % os.path.join(
+                self.spec['llvm'].prefix.bin, 'flang'),
+            '-DFLANG_LIBOMP=%s' % find_libraries(
+                'libomp', root=self.spec['llvm'].prefix.lib)
+        ]
+
+        return options
+
+    @run_after('install')
+    def post_install(self):
+        # we are installing flang in a path different from llvm, so we
+        # create a wrapper with -L for e.g. libflangrti.so and -I for
+        # e.g. iso_c_binding.mod. -B is needed to help flang to find
+        # flang1 and flang2. rpath_arg is needed so that executables
+        # generated by flang can find libflang later.
+        flang = os.path.join(self.spec.prefix.bin, 'flang')
+        with open(flang, 'w') as out:
+            out.write('#!/bin/bash\n')
+            out.write(
+                '{0} -I{1} -L{2} {3}{4} -B{5} "$@"\n'.format(
+                    os.path.join(self.spec['llvm'].prefix.bin, 'flang'),
+                    self.prefix.include, self.prefix.lib,
+                    self.compiler.fc_rpath_arg, self.prefix.lib,
+                    self.spec.prefix.bin))
+            out.close()
+        chmod = which('chmod')
+        chmod('+x', flang)