Separate Apple Clang from LLVM Clang (#17110)

* Separate Apple Clang from LLVM Clang

Apple Clang is a compiler of its own. All places
referring to "-apple" suffix have been updated.

* Hack to use a dash in 'apple-clang'

To be able to use autodoc from Sphinx we need
a valid Python name for the module that contains
Apple's Clang code.

* Updated packages to account for the existence of apple-clang

Co-authored-by: Adam J. Stewart <ajstewart426@gmail.com>

* Added unit test for XCode related functions

Co-authored-by: Gregory Becker <becker33@llnl.gov>
Co-authored-by: Adam J. Stewart <ajstewart426@gmail.com>

lib/spack/llnl/util/cpu/microarchitecture.py

@@ -204,10 +204,22 @@ def optimization_flags(self, compiler, version):
             compiler (str): name of the compiler to be used
             version (str): version of the compiler to be used
         """
-        # If we don't have information on compiler return an empty string
-        if compiler not in self.compilers:
+        # If we don't have information on compiler at all
+        # return an empty string
+        if compiler not in self.family.compilers:
             return ''
 
+        # If we have information but it stops before this
+        # microarchitecture, fall back to the best known target
+        if compiler not in self.compilers:
+            best_target = [
+                x for x in self.ancestors if compiler in x.compilers
+            ][0]
+            msg = ("'{0}' compiler is known to optimize up to the '{1}'"
+                   " microarchitecture in the '{2}' architecture family")
+            msg = msg.format(compiler, best_target, best_target.family)
+            raise UnsupportedMicroarchitecture(msg)
+
         # If we have information on this compiler we need to check the
         # version being used
         compiler_info = self.compilers[compiler]
@@ -219,15 +231,10 @@ def optimization_flags(self, compiler, version):
         def satisfies_constraint(entry, version):
             min_version, max_version = entry['versions'].split(':')
 
-            # Check version suffixes
-            min_version, min_suffix = version_components(min_version)
-            max_version, max_suffix = version_components(max_version)
-            version, suffix = version_components(version)
-
-            # If the suffixes are not all equal there's no match
-            if ((suffix != min_suffix and min_version) or
-                (suffix != max_suffix and max_version)):
-                return False
+            # Extract numeric part of the version
+            min_version, _ = version_components(min_version)
+            max_version, _ = version_components(max_version)
+            version, _ = version_components(version)
 
             # Assume compiler versions fit into semver
             tuplify = lambda x: tuple(int(y) for y in x.split('.'))

lib/spack/llnl/util/cpu/microarchitectures.json

@@ -61,12 +61,14 @@
             "flags": "-march={name} -mtune={name}"
           }
         ],
-        "clang": [
+        "apple-clang": [
           {
-            "versions": "0.0.0-apple:",
+            "versions": ":",
             "name": "x86-64",
             "flags": "-march={name}"
-          },
+          }
+        ],
+        "clang": [
           {
             "versions": ":",
             "name": "x86-64",