clang: add 'version_argument', remove redundant method (#17071)

lib/spack/spack/compilers/clang.py

@@ -50,6 +50,8 @@ class Clang(Compiler):
     # Subclasses use possible names of Fortran 90 compiler
     fc_names = ['flang', 'gfortran', 'xlf90_r']
 
+    version_argument = '--version'
+
     @property
     def debug_flags(self):
         return ['-gcodeview', '-gdwarf-2', '-gdwarf-3', '-gdwarf-4',
@@ -201,26 +203,6 @@ def fc_pic_flag(self):
 
     required_libs = ['libclang']
 
-    @classmethod
-    @llnl.util.lang.memoized
-    def default_version(cls, comp):
-        """The ``--version`` option works for clang compilers.
-        On most platforms, output looks like this::
-
-            clang version 3.1 (trunk 149096)
-            Target: x86_64-unknown-linux-gnu
-            Thread model: posix
-
-        On macOS, it looks like this::
-
-            Apple LLVM version 7.0.2 (clang-700.1.81)
-            Target: x86_64-apple-darwin15.2.0
-            Thread model: posix
-        """
-        compiler = Executable(comp)
-        output = compiler('--version', output=str, error=str)
-        return cls.extract_version_from_output(output)
-
     @classmethod
     @llnl.util.lang.memoized
     def extract_version_from_output(cls, output):

lib/spack/spack/test/compilers/basics.py

@@ -389,6 +389,7 @@ def test_clang_flags():
     supported_flag_test("fc_pic_flag",  "-fPIC", "clang@2.0.0-apple")
 
     # non-Apple Clang.
+    supported_flag_test("version_argument", "--version", "clang@foo.bar")
     supported_flag_test("openmp_flag", "-fopenmp", "clang@3.3")
     unsupported_flag_test("cxx11_flag", "clang@3.2")
     supported_flag_test("cxx11_flag", "-std=c++11", "clang@3.3")