diff --git a/share/spack/setup-env.sh b/share/spack/setup-env.sh
index 4faae0d2c9da5f0e79305be4c1adb219c3f351a3..6503728d8f256abe6087a1b459a66738b2f4d5fc 100755
--- a/share/spack/setup-env.sh
+++ b/share/spack/setup-env.sh
@@ -55,7 +55,6 @@
 # avoids the need to come up with a user-friendly naming scheme for
 # spack dotfiles.
 ########################################################################
-arrtest[0]='test' || (echo 'Failure: arrays not supported in this version of bash.' && exit 2)
 
 function spack {
     # save raw arguments into an array before butchering them
diff --git a/var/spack/packages/binutils/package.py b/var/spack/packages/binutils/package.py
index 123f4598f696a52495042a2f367421ed4bdbd92e..a79fc5fb6996dcd48b93005dd35e6606843300aa 100644
--- a/var/spack/packages/binutils/package.py
+++ b/var/spack/packages/binutils/package.py
@@ -11,6 +11,7 @@ class Binutils(Package):
 
     # Add a patch that creates binutils libiberty_pic.a which is preferred by OpenSpeedShop and cbtf-krell
     variant('krellpatch', default=False, description="build with openspeedshop based patch.")
+    variant('gold', default=True, description="build the gold linker")
     patch('binutilskrell-2.24.patch', when='@2.24+krellpatch')
 
     variant('libiberty', default=False, description='Also install libiberty.')
@@ -26,6 +27,10 @@ def install(self, spec, prefix):
             '--enable-targets=all',
             '--with-sysroot=/']
 
+        if '+gold' in spec:
+            configure_args.append('--enable-gold')
+            configure_args.append('--enable-plugins')
+
         if '+libiberty' in spec:
             configure_args.append('--enable-install-libiberty')
 
diff --git a/var/spack/packages/clang/package.py b/var/spack/packages/clang/package.py
index e46e08d5f11b7609ee5835d37f105fd07aa5a6a8..99e805d15d047acafa2324b85bc25cdeeaf07b9f 100644
--- a/var/spack/packages/clang/package.py
+++ b/var/spack/packages/clang/package.py
@@ -36,20 +36,42 @@ class Clang(Package):
     homepage = 'http://clang.llvm.org'
     url = 'http://llvm.org/releases/3.7.0/cfe-3.7.0.src.tar.xz'
 
-    depends_on('llvm@3.7.0', when='@3.7.0')
-    depends_on('llvm@3.6.2', when='@3.6.2')
-    depends_on('llvm@3.5.1', when='@3.5.1')
-
-    version('3.7.0', '8f9d27335e7331cf0a4711e952f21f01', url='http://llvm.org/releases/3.7.0/cfe-3.7.0.src.tar.xz')
-    version('3.6.2', 'ff862793682f714bb7862325b9c06e20', url='http://llvm.org/releases/3.6.2/cfe-3.6.2.src.tar.xz')
-    version('3.5.1', '93f9532f8f7e6f1d8e5c1116907051cb', url='http://llvm.org/releases/3.5.1/cfe-3.5.1.src.tar.xz')
-
-    ##########
-    # @3.7.0
-    resource(name='clang-tools-extra',
-             url='http://llvm.org/releases/3.7.0/clang-tools-extra-3.7.0.src.tar.xz',
-             md5='d5a87dacb65d981a427a536f6964642e', destination='tools', when='@3.7.0')
-    ##########
+    clang_url = 'http://llvm.org/releases/%(version)s/cfe-%(version)s.src.tar.xz'
+
+    resources = {
+                    'clang-tools-extra' : {
+                        'url' : 'http://llvm.org/releases/%(version)s/clang-tools-extra-%(version)s.src.tar.xz',
+                        'destination' : 'tools'
+                    },
+                }
+    releases = [ 
+                  {
+                    'version' : '3.7.0',
+                    'md5':'8f9d27335e7331cf0a4711e952f21f01',
+                    'resources' : { 'clang-tools-extra' : 'd5a87dacb65d981a427a536f6964642e' }
+                  },
+                  {
+                    'version' : '3.6.2',
+                    'md5':'ff862793682f714bb7862325b9c06e20',
+                    'resources' : { 'clang-tools-extra' : '3ebc1dc41659fcec3db1b47d81575e06' }
+                  },
+                  {
+                    'version' : '3.5.1',
+                    'md5':'93f9532f8f7e6f1d8e5c1116907051cb',
+                    'resources' : { 'clang-tools-extra' : 'f13f31ed3038acadc6fa63fef812a246' }
+                  },
+               ]
+
+    for release in releases:
+        version(release['version'], release['md5'], url=clang_url % release)
+        depends_on('llvm@%(version)s' % release, when='@%(version)s' % release)
+
+        for name, md5 in release['resources'].items():
+            resource(name=name,
+                     url=resources[name]['url'] % release,
+                     md5=md5,
+                     destination=resources[name]['destination'],
+                     when='@%(version)s' % release)
 
     def install(self, spec, prefix):
         env['CXXFLAGS'] = self.compiler.cxx11_flag
@@ -92,4 +114,4 @@ def do_link(source_dir, destination_dir):
         # Link folder and files in lib
         llvm_dir = clang_lib_dir_at(spec['llvm'].prefix)
         clang_dir = clang_lib_dir_at(self.prefix)
-        do_link(llvm_dir, clang_dir)
\ No newline at end of file
+        do_link(llvm_dir, clang_dir)
diff --git a/var/spack/packages/gcc/package.py b/var/spack/packages/gcc/package.py
index 7ec160d5957513f3136d13c6443a62469570aa29..da90c220237620fe33f4fa580a60242b84b984f8 100644
--- a/var/spack/packages/gcc/package.py
+++ b/var/spack/packages/gcc/package.py
@@ -52,19 +52,45 @@ class Gcc(Package):
     depends_on("mpfr")
     depends_on("gmp")
     depends_on("mpc")     # when @4.5:
-    depends_on("binutils~libiberty")
+    depends_on("binutils~libiberty+gold")
 
     # Save these until we can do optional deps.
     depends_on("isl", when=DEPENDS_ON_ISL_PREDICATE)
     #depends_on("ppl")
     #depends_on("cloog")
 
+    variant('lang_go',      default=True,  description="Include support for the go language")
+    variant('lang_fortran', default=True,  description="Include support for the Fortran language")
+    variant('lang_c',       default=True,  description="Include support for the C language")
+    variant('lang_cxx',     default=True,  description="Include support for the C++ language")
+    variant('lang_ada',     default=False, description="Include support for the ada language")
+    variant('lang_java',    default=False, description="Include support for the java language")
+    variant('lang_objc',    default=True,  description="Include support for the Objective-C language")
+    variant('lang_objcxx',  default=True,  description="Include support for the Objective-C++ language")
+    variant('jit',          default=False, description="Include support for JIT")
+
     def install(self, spec, prefix):
         # libjava/configure needs a minor fix to install into spack paths.
         filter_file(r"'@.*@'", "'@[[:alnum:]]*@'", 'libjava/configure', string=True)
 
-        enabled_languages = set(('c', 'c++', 'fortran', 'java', 'objc'))
-        if spec.satisfies("@4.7.1:"):
+        enabled_languages = set()#('c', 'c++', 'fortran', 'java', 'objc')
+        if '+lang_fortran' in spec:
+            enabled_languages.add('fortran')
+        if '+lang_c' in spec:
+            enabled_languages.add('c')
+        if '+lang_cxx' in spec:
+            enabled_languages.add('c++')
+        if '+lang_java' in spec:
+            enabled_languages.add('java')
+        if '+lang_objc' in spec:
+            enabled_languages.add('objc')
+        if '+lang_objcxx' in spec:
+            enabled_languages.add('obj-c++')
+        if '+lang_ada' in spec:
+            enabled_languages.add('ada')
+        if '+jit' in spec:
+            enabled_languages.add('jit')
+        if spec.satisfies("@4.7.1:") and '+lang_go' in spec:
             enabled_languages.add('go')
 
         # Generic options to compile GCC
diff --git a/var/spack/packages/llvm/package.py b/var/spack/packages/llvm/package.py
index a3307584e08b2b5bc57fe98af798ca375d963579..8a36a873675acfb2635ef7bbed7b2971b5a506c4 100644
--- a/var/spack/packages/llvm/package.py
+++ b/var/spack/packages/llvm/package.py
@@ -3,8 +3,9 @@
 # Produced at the Lawrence Livermore National Laboratory.
 #
 # This file is part of Spack.
-# Written by David Beckingsale, david@llnl.gov, All rights reserved.
-# LLNL-CODE-647188
+# Written by David Beckingsale, david@llnl.gov
+# Heavily modified by others, including Tom Scogland, scogland1@llnl.gov
+# All rights reserved. LLNL-CODE-647188
 #
 # For details, see https://github.com/llnl/spack
 # Please also see the LICENSE file for our notice and the LGPL.
@@ -23,6 +24,7 @@
 # Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 ##############################################################################
 from spack import *
+import os
 
 
 class Llvm(Package):
@@ -40,33 +42,147 @@ class Llvm(Package):
     version('3.5.1', '2d3d8004f38852aa679e5945b8ce0b14', url='http://llvm.org/releases/3.5.1/llvm-3.5.1.src.tar.xz')
     version('3.0', 'a8e5f5f1c1adebae7b4a654c376a6005', url='http://llvm.org/releases/3.0/llvm-3.0.tar.gz') # currently required by mesa package
 
+    variant('debug', default=False, description="Build a debug version of LLVM, this increases binary size considerably")
+    variant('clang', default=True, description="Build the LLVM C/C++/Objective-C compiler frontend")
+    variant('clang_extra', default=True, description="Build the clang extra tools")
+    variant('lldb', default=True, description="Build the LLVM debugger")
+    variant('internal_unwind', default=True, description="Build and use the libcxxabi built-in unwinder")
+    variant('compiler-rt', default=False, description="Compiler runtime including sanitizers and unwinding libraries")
+    variant('gold', default=True, description="Add support for the gold linker and build the gold linker plugin for LTO")
+
+    # Universal dependency
     depends_on('python@2.7:')
 
-    variant('libcxx', default=False, description="Builds the LLVM Standard C++ library targeting C++11")
+    # lldb dependencies
+    depends_on('ncurses', when='+lldb')
+    depends_on('swig', when='+lldb')
+    depends_on('libedit', when='+lldb')
+
+    # gold support
+    depends_on('binutils+gold', when='+gold')
+
+    base_url =  'http://llvm.org/releases/%%(version)s/%(pkg)s-%%(version)s.src.tar.xz'
+    llvm_url = base_url % { 'pkg' : 'llvm'}
+
+    resources = {
+                    'compiler-rt' : {
+                        'url' : base_url % { 'pkg' : 'compiler-rt'},
+                        'destination' : 'projects',
+                        'placement' : 'compiler-rt',
+                    },
+                    'openmp' : {
+                        'url' : base_url % { 'pkg' : 'openmp'},
+                        'destination' : 'projects',
+                        'placement' : 'openmp',
+                    },
+                    'libcxx' : {
+                        'url' : base_url % { 'pkg' : 'libcxx'},
+                        'destination' : 'projects',
+                        'placement' : 'libcxx',
+                    },
+                    'libcxxabi' : {
+                        'url' :  base_url % { 'pkg' : 'libcxxabi'},
+                        'destination' : 'projects',
+                        'placement' : 'libcxxabi',
+                    },
+                    'clang' : {
+                        'url' :  base_url % { 'pkg' : 'cfe'},
+                        'destination' : 'tools',
+                        'placement' : 'clang',
+                    },
+                    'clang-tools-extra' : {
+                        'url' :  base_url % { 'pkg' : 'clang-tools-extra'},
+                        'destination' : 'tools/clang/tools',
+                        'placement' : 'clang-tools-extra',
+                    },
+                    'lldb' : {
+                        'url' :  base_url % { 'pkg' : 'lldb'},
+                        'destination' : 'tools',
+                        'placement' : 'lldb',
+                    },
+                    'polly' : {
+                        'url' :  base_url % { 'pkg' : 'polly'},
+                        'destination' : 'tools',
+                        'placement' : 'polly',
+                    },
+                    'llvm-libunwind' : {
+                        'url' :  base_url % { 'pkg' : 'libunwind'},
+                        'destination' : 'projects',
+                        'placement' : 'libunwind',
+                    },
+                }
+    releases = [ 
+                  {
+                    'version' : '3.7.0',
+                    'md5':'b98b9495e5655a672d6cb83e1a180f8e',
+                    'resources' : { 
+                        # FIXME: compiler-rt 
+                        # 'compiler-rt' : '383c10affd513026f08936b5525523f5',
+                        'openmp' : 'f482c86fdead50ba246a1a2b0bbf206f',
+                        'polly' : '32f93ffc9cc7e042df22089761558f8b',
+                        'libcxx' : '46aa5175cbe1ad42d6e9c995968e56dd',
+                        'libcxxabi' : '5aa769e2fca79fa5335cfae8f6258772',
+                        'clang' : '8f9d27335e7331cf0a4711e952f21f01',
+                        'clang-tools-extra' : 'd5a87dacb65d981a427a536f6964642e',
+                        'lldb' : 'e5931740400d1dc3e7db4c7ba2ceff68',
+                        'llvm-libunwind' : '9a75392eb7eb8ed5c0840007e212baf5',
+                        }
+                  },
+                  {
+                    'version' : '3.6.2',
+                    'md5':'0c1ee3597d75280dee603bae9cbf5cc2',
+                    'resources' : { 
+                        'compiler-rt' : 'e3bc4eb7ba8c39a6fe90d6c988927f3c',
+                        'openmp' : '65dd5863b9b270960a96817e9152b123',
+                        'libcxx' : '22214c90697636ef960a49aef7c1823a',
+                        'libcxxabi' : '17518e361e4e228f193dd91e8ef54ba2',
+                        'clang' : 'ff862793682f714bb7862325b9c06e20',
+                        'clang-tools-extra' : '3ebc1dc41659fcec3db1b47d81575e06',
+                        'lldb' : '51e5eb552f777b950bb0ff326e60d5f0',
+                        }
+                  },
+                  {
+                    'version' : '3.5.1',
+                    'md5':'2d3d8004f38852aa679e5945b8ce0b14',
+                    'resources' : { 
+                        'compiler-rt' : 'd626cfb8a9712cb92b820798ab5bc1f8',
+                        'openmp' : '121ddb10167d7fc38b1f7e4b029cf059',
+                        'libcxx' : '406f09b1dab529f3f7879f4d548329d2',
+                        'libcxxabi' : 'b22c707e8d474a99865ad3c521c3d464',
+                        'clang' : '93f9532f8f7e6f1d8e5c1116907051cb',
+                        'clang-tools-extra' : 'f13f31ed3038acadc6fa63fef812a246',
+                        'lldb' : 'cc5ea8a414c62c33e760517f8929a204',
+                        }
+                  },
+               ]
 
-    ##########
-    # @3.7.0
-    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', placement='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', placement='libcxxabi', when='+libcxx@3.7.0')
-    ##########
+    for release in releases:
+        version(release['version'], release['md5'], url=llvm_url % release)
+
+        for name, md5 in release['resources'].items():
+            resource(name=name,
+                     url=resources[name]['url'] % release,
+                     md5=md5,
+                     destination=resources[name]['destination'],
+                     when='@%(version)s' % release,
+                     placement=resources[name].get('placement', None))
 
     def install(self, spec, prefix):
         env['CXXFLAGS'] = self.compiler.cxx11_flag
+        build_type = 'Debug'  if '+debug' in spec else 'Release'
+
+        if  '+clang' not in spec:
+            if '+clang_extra' in spec:
+                raise SpackException('The clang_extra variant requires the clang variant to be selected')
+            if '+lldb' in spec:
+                raise SpackException('The lldb variant requires the clang variant to be selected')
 
         with working_dir('spack-build', create=True):
             cmake('..',
+                  '-DCMAKE_RELEASE_TYPE=' + build_type,
                   '-DLLVM_REQUIRES_RTTI:BOOL=ON',
                   '-DPYTHON_EXECUTABLE:PATH=%s/bin/python' % spec['python'].prefix,
                   *std_cmake_args)
-            make()
+            make("VERBOSE=1")
             make("install")
+