reource directive accepts 'basename' keyword

llvm : libc++ variant

lib/spack/spack/directives.py

@@ -276,10 +276,12 @@ def resource(pkg, **kwargs):
     * 'when' : represents the condition upon which the resource is needed (optional)
     * 'destination' : path where to extract / checkout the resource (optional). This path must be a relative path,
     and it must fall inside the stage area of the main package.
+    * 'basename' : basename of the resource source folder within destination (optional).
 
     """
     when = kwargs.get('when', pkg.name)
     destination = kwargs.get('destination', "")
+    basename = kwargs.get('basename', None)
     # Check if the path is relative
     if os.path.isabs(destination):
         message = "The destination keyword of a resource directive can't be an absolute path.\n"
@@ -296,7 +298,8 @@ def resource(pkg, **kwargs):
     resources = pkg.resources.setdefault(when_spec, [])
     fetcher = from_kwargs(**kwargs)
     name = kwargs.get('name')
-    resources.append(Resource(name, fetcher, destination))
+    resources.append(Resource(name, fetcher, destination, basename))
+
 
 class DirectiveError(spack.error.SpackError):
     """This is raised when something is wrong with a package directive."""

lib/spack/spack/package.py

@@ -681,7 +681,8 @@ def _expand_archive(stage, name=self.name):
         for resource in resources:
             stage = resource.fetcher.stage
             _expand_archive(stage, resource.name)
-            link_path = join_path(self.stage.source_path, resource.destination, os.path.basename(stage.source_path))
+            basename = os.path.basename(stage.source_path) if resource.basename is None else resource.basename
+            link_path = join_path(self.stage.source_path, resource.destination, basename)
             if not os.path.exists(link_path):
                 # Create a symlink
                 os.symlink(stage.source_path, link_path)

lib/spack/spack/resource.py

@@ -27,11 +27,13 @@
 package to enable optional features.
 """
 
+
 class Resource(object):
     """
     Represents an optional resource. Aggregates a name, a fetcher and a destination.
     """
-    def __init__(self, name, fetcher, destination):
+    def __init__(self, name, fetcher, destination, basename):
         self.name = name
         self.fetcher = fetcher
         self.destination = destination
+        self.basename = basename

var/spack/packages/llvm/package.py

@@ -41,15 +41,22 @@ class Llvm(Package):
 
     depends_on('python@2.7:')
 
+    variant('libcxx', default=False, description="Builds the LLVM Standard C++ library targeting C++11")
+
     ##########
     # @3.7.0
-    # TODO : Add support for libc++ <- libc++ABI <- libunwind with variant?
     resource(name='compiler-rt',
              url='http://llvm.org/releases/3.7.0/compiler-rt-3.7.0.src.tar.xz', md5='383c10affd513026f08936b5525523f5',
              destination='projects', when='@3.7.0')
     resource(name='openmp',
              url='http://llvm.org/releases/3.7.0/openmp-3.7.0.src.tar.xz', md5='f482c86fdead50ba246a1a2b0bbf206f',
              destination='projects', when='@3.7.0')
+    resource(name='libcxx',
+             url='http://llvm.org/releases/3.7.0/libcxx-3.7.0.src.tar.xz', md5='46aa5175cbe1ad42d6e9c995968e56dd',
+             destination='projects', basename='libcxx', when='+libcxx@3.7.0')
+    resource(name='libcxxabi',
+             url='http://llvm.org/releases/3.7.0/libcxxabi-3.7.0.src.tar.xz', md5='5aa769e2fca79fa5335cfae8f6258772',
+             destination='projects', basename='libcxxabi', when='+libcxx@3.7.0')
     ##########
 
     def install(self, spec, prefix):