compilers: add arm compiler detection to Spack

- added arm.py with support for detecting `armclang` and `armflang`

Co-authored-by: Srinath Vadlamani <srinath.vadlamani@arm.com>

lib/spack/spack/compilers/arm.py

@@ -0,0 +1,73 @@
+# Copyright 2013-2018 Lawrence Livermore National Security, LLC and other
+# Spack Project Developers. See the top-level COPYRIGHT file for details.
+#
+# SPDX-License-Identifier: (Apache-2.0 OR MIT)
+
+import re
+
+from spack.compiler import Compiler, _version_cache
+from spack.util.executable import Executable
+
+
+class Arm(Compiler):
+    # Subclasses use possible names of C compiler
+    cc_names = ['armclang']
+
+    # Subclasses use possible names of C++ compiler
+    cxx_names = ['armclang++']
+
+    # Subclasses use possible names of Fortran 77 compiler
+    f77_names = ['armflang']
+
+    # Subclasses use possible names of Fortran 90 compiler
+    fc_names = ['armflang']
+
+    # Named wrapper links within lib/spack/env
+    link_paths = {'cc': 'clang/clang',
+                  'cxx': 'clang/clang++',
+                  'f77': 'clang/flang',
+                  'fc': 'clang/flang'}
+
+    @property
+    def openmp_flag(self):
+        return "-fopenmp"
+
+    @property
+    def cxx11_flag(self):
+        return "-std=c++11"
+
+    @property
+    def cxx14_flag(self):
+        return "-std=c++14"
+
+    @property
+    def cxx17_flag(self):
+        return "-std=c++1z"
+
+    @property
+    def pic_flag(self):
+        return "-fPIC"
+
+    @classmethod
+    def default_version(cls, comp):
+        if comp not in _version_cache:
+            compiler = Executable(comp)
+            output = compiler('--version', output=str, error=str)
+
+            ver = 'unknown'
+            match = re.search(r'Arm C/C++/Fortran Compiler version ([^ )]+)',
+                              output)
+            if match:
+                ver = match.group(1)
+
+            _version_cache[comp] = ver
+
+        return _version_cache[comp]
+
+    @classmethod
+    def fc_version(cls, fc):
+        return cls.default_version(fc)
+
+    @classmethod
+    def f77_version(cls, f77):
+        return cls.fc_version(f77)