Merge pull request #989 from LLNL/features/cflags-documentation

updated documentation for cflags PR

4 files changed, 158 insertions, 74 deletions

diff --git a/lib/spack/docs/basic_usage.rst b/lib/spack/docs/basic_usage.rst
index 6efed83621..2eed9dddd4 100644
--- a/lib/spack/docs/basic_usage.rst
+++ b/lib/spack/docs/basic_usage.rst
@@ -102,8 +102,8 @@ that the packages is installed:
    ==> adept-utils is already installed in /home/gamblin2/spack/opt/chaos_5_x86_64_ib/gcc@4.4.7/adept-utils@1.0-5adef8da.
    ==> Trying to fetch from https://github.com/hpc/mpileaks/releases/download/v1.0/mpileaks-1.0.tar.gz
    ######################################################################## 100.0%
-   ==> Staging archive: /home/gamblin2/spack/var/spack/stage/mpileaks@1.0%gcc@4.4.7=chaos_5_x86_64_ib-59f6ad23/mpileaks-1.0.tar.gz
-   ==> Created stage in /home/gamblin2/spack/var/spack/stage/mpileaks@1.0%gcc@4.4.7=chaos_5_x86_64_ib-59f6ad23.
+   ==> Staging archive: /home/gamblin2/spack/var/spack/stage/mpileaks@1.0%gcc@4.4.7 arch=chaos_5_x86_64_ib-59f6ad23/mpileaks-1.0.tar.gz
+   ==> Created stage in /home/gamblin2/spack/var/spack/stage/mpileaks@1.0%gcc@4.4.7 arch=chaos_5_x86_64_ib-59f6ad23.
    ==> No patches needed for mpileaks.
    ==> Building mpileaks.
 
@@ -132,10 +132,10 @@ sites, as installing a version that one user needs will not disrupt
 existing installations for other users.
 
 In addition to different versions, Spack can customize the compiler,
-compile-time options (variants), and platform (for cross compiles) of
-an installation.  Spack is unique in that it can also configure the
-*dependencies* a package is built with.  For example, two
-configurations of the same version of a package, one built with boost
+compile-time options (variants), compiler flags, and platform (for
+cross compiles) of an installation.  Spack is unique in that it can
+also configure the *dependencies* a package is built with.  For example,
+two configurations of the same version of a package, one built with boost
 1.39.0, and the other version built with version 1.43.0, can coexist.
 
 This can all be done on the command line using the *spec* syntax.
@@ -334,6 +334,11 @@ of libelf would look like this:
    -- chaos_5_x86_64_ib / gcc@4.4.7 --------------------------------
    libdwarf@20130729-d9b90962
 
+We can also search for packages that have a certain attribute. For example,
+``spack find -l libdwarf +debug`` will show only installations of libdwarf
+with the 'debug' compile-time option enabled, while ``spack find -l +debug``
+will find every installed package with a 'debug' compile-time option enabled.
+
 The full spec syntax is discussed in detail in :ref:`sec-specs`.
 
 
@@ -463,6 +468,26 @@ For compilers, like ``clang``, that do not support Fortran, put
 Once you save the file, the configured compilers will show up in the
 list displayed by ``spack compilers``.
 
+You can also add compiler flags to manually configured compilers. The
+valid flags are ``cflags``, ``cxxflags``, ``fflags``, ``cppflags``,
+``ldflags``, and ``ldlibs``. For example,::
+
+    ...
+    chaos_5_x86_64_ib:
+      ...
+      intel@15.0.0:
+          cc: /usr/local/bin/icc-15.0.024-beta
+          cxx: /usr/local/bin/icpc-15.0.024-beta
+          f77: /usr/local/bin/ifort-15.0.024-beta
+          fc: /usr/local/bin/ifort-15.0.024-beta
+          cppflags: -O3 -fPIC
+      ...
+
+These flags will be treated by spack as if they were enterred from
+the command line each time this compiler is used. The compiler wrappers
+then inject those flags into the compiler command. Compiler flags
+enterred from the command line will be discussed in more detail in the
+following section.
 
 .. _sec-specs:
 
@@ -480,7 +505,7 @@ the full syntax of specs.
 
 Here is an example of a much longer spec than we've seen thus far::
 
-   mpileaks @1.2:1.4 %gcc@4.7.5 +debug -qt =bgqos_0 ^callpath @1.1 %gcc@4.7.2
+   mpileaks @1.2:1.4 %gcc@4.7.5 +debug -qt arch=bgq_os ^callpath @1.1 %gcc@4.7.2
 
 If provided to ``spack install``, this will install the ``mpileaks``
 library at some version between ``1.2`` and ``1.4`` (inclusive),
@@ -498,8 +523,12 @@ More formally, a spec consists of the following pieces:
 * ``%`` Optional compiler specifier, with an optional compiler version
   (``gcc`` or ``gcc@4.7.3``)
 * ``+`` or ``-`` or ``~`` Optional variant specifiers (``+debug``,
-  ``-qt``, or ``~qt``)
-* ``=`` Optional architecture specifier (``bgqos_0``)
+  ``-qt``, or ``~qt``) for boolean variants
+* ``name=<value>`` Optional variant specifiers that are not restricted to
+boolean variants
+* ``name=<value>`` Optional compiler flag specifiers. Valid flag names are
+``cflags``, ``cxxflags``, ``fflags``, ``cppflags``, ``ldflags``, and ``ldlibs``.
+* ``arch=<value>`` Optional architecture specifier (``arch=bgq_os``)
 * ``^`` Dependency specs (``^callpath@1.1``)
 
 There are two things to notice here.  The first is that specs are
@@ -579,7 +608,7 @@ compilers, variants, and architectures just like any other spec.
 Specifiers are associated with the nearest package name to their left.
 For example, above, ``@1.1`` and ``%gcc@4.7.2`` associates with the
 ``callpath`` package, while ``@1.2:1.4``, ``%gcc@4.7.5``, ``+debug``,
-``-qt``, and ``=bgqos_0`` all associate with the ``mpileaks`` package.
+``-qt``, and ``arch=bgq_os`` all associate with the ``mpileaks`` package.
 
 In the diagram above, ``mpileaks`` depends on ``mpich`` with an
 unspecified version, but packages can depend on other packages with
@@ -635,22 +664,25 @@ based on site policies.
 Variants
 ~~~~~~~~~~~~~~~~~~~~~~~
 
-.. Note::
-
-   Variants are not yet supported, but will be in the next Spack
-   release (0.9), due in Q2 2015.
-
-Variants are named options associated with a particular package, and
-they can be turned on or off.  For example, above, supplying
-``+debug`` causes ``mpileaks`` to be built with debug flags.  The
-names of particular variants available for a package depend on what
-was provided by the package author.  ``spack info <package>`` will
+Variants are named options associated with a particular package. They are
+optional, as each package must provide default values for each variant it
+makes available. Variants can be specified using
+a flexible parameter syntax ``name=<value>``. For example,
+``spack install libelf debug=True`` will install libelf build with debug
+flags. The names of particular variants available for a package depend on
+what was provided by the package author. ``spack into <package>`` will
 provide information on what build variants are available.
 
-Depending on the package a variant may be on or off by default.  For
-``mpileaks`` here, ``debug`` is off by default, and we turned it on
-with ``+debug``.  If a package is on by default you can turn it off by
-either adding ``-name`` or ``~name`` to the spec.
+For compatibility with earlier versions, variants which happen to be
+boolean in nature can be specified by a syntax that represents turning
+options on and off. For example, in the previous spec we could have
+supplied ``libelf +debug`` with the same effect of enabling the debug
+compile time option for the libelf package.
+
+Depending on the package a variant may have any default value.  For
+``libelf`` here, ``debug`` is ``False`` by default, and we turned it on
+with ``debug=True`` or ``+debug``.  If a package is ``True`` by default
+you can turn it off by either adding ``-name`` or ``~name`` to the spec.
 
 There are two syntaxes here because, depending on context, ``~`` and
 ``-`` may mean different things.  In most shells, the following will
@@ -662,7 +694,7 @@ result in the shell performing home directory substitution:
    mpileaks~debug    # use this instead
 
 If there is a user called ``debug``, the ``~`` will be incorrectly
-expanded.  In this situation, you would want to write ``mpileaks
+expanded.  In this situation, you would want to write ``libelf
 -debug``.  However, ``-`` can be ambiguous when included after a
 package name without spaces:
 
@@ -677,12 +709,35 @@ package, not a request for ``mpileaks`` built without ``debug``
 options.  In this scenario, you should write ``mpileaks~debug`` to
 avoid ambiguity.
 
-When spack normalizes specs, it prints them out with no spaces and
-uses only ``~`` for disabled variants.  We allow ``-`` and spaces on
-the command line is provided for convenience and legibility.
+When spack normalizes specs, it prints them out with no spaces boolean
+variants using the backwards compatibility syntax and uses only ``~``
+for disabled boolean variants.  We allow ``-`` and spaces on the command
+line is provided for convenience and legibility.
 
 
-Architecture specifier
+Compiler Flags
+~~~~~~~~~~~~~~~~~~~~~~~
+
+Compiler flags are specified using the same syntax as non-boolean variants,
+but fulfill a different purpose. While the function of a variant is set by
+the package, compiler flags are used by the compiler wrappers to inject
+flags into the compile line of the build. Additionally, compiler flags are
+inherited by dependencies. ``spack install libdwarf cppflags=\"-g\"`` will
+install both libdwarf and libelf with the ``-g`` flag injected into their
+compile line.
+
+Notice that the value of the compiler flags must be escape quoted on the
+command line. From within python files, the same spec would be specified
+``libdwarf cppflags="-g"``. This is necessary because of how the shell
+handles the quote symbols.
+
+The six compiler flags are injected in the order of implicit make commands
+in gnu autotools. If all flags are set, the order is
+``$cppflags $cflags|$cxxflags $ldflags command $ldlibs`` for C and C++ and
+``$fflags $cppflags $ldflags command $ldlibs`` for fortran.
+
+
+Architecture specifiers
 ~~~~~~~~~~~~~~~~~~~~~~~
 
 .. Note::
@@ -690,12 +745,9 @@ Architecture specifier
    Architecture specifiers are part of specs but are not yet
    functional. They will be in Spack version 1.0, due in Q3 2015.
 
-The architecture specifier starts with a ``=`` and also comes after
-some package name within a spec.  It allows a user to specify a
-particular architecture for the package to be built.  This is mostly
-used for architectures that need cross-compilation, and in most cases,
-users will not need to specify the architecture when they install a
-package.
+The architecture specifier looks identical to a variant specifier for a
+non-boolean variant. The architecture can be specified only using the
+reserved name ``arch`` (``arch=bgq_os``).
 
 
 .. _sec-virtual-dependencies:
@@ -773,6 +825,23 @@ any MPI implementation will do.  If another package depends on
 error.  Likewise, if you try to plug in some package that doesn't
 provide MPI, Spack will raise an error.
 
+Specifying Specs by Hash
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Complicated specs can become cumbersome to enter on the command line,
+especially when many of the qualifications are necessary to
+distinguish between similar installs, for example when using the
+``uninstall`` command. To avoid this, when referencing an existing spec,
+Spack allows you to reference specs by their hash. We previously
+discussed the spec hash that Spack computes. In place of a spec in any
+command, substitute ``/<hash>`` where ``<hash>`` is any amount from
+the beginning of a spec hash. If the given spec hash is sufficient
+to be unique, Spack will replace the reference with the spec to which
+it refers. Otherwise, it will prompt for a more qualified hash.
+
+Note that this will not work to reinstall a depencency uninstalled by
+``spack uninstall -f``.
+
 .. _spack-providers:
 
 ``spack providers``
@@ -1002,8 +1071,8 @@ than one installed package matches it), then Spack will warn you:
 
    $ spack load libelf
    ==> Error: Multiple matches for spec libelf.  Choose one:
-   libelf@0.8.13%gcc@4.4.7=chaos_5_x86_64_ib
-   libelf@0.8.13%intel@15.0.0=chaos_5_x86_64_ib
+   libelf@0.8.13%gcc@4.4.7 arch=chaos_5_x86_64_ib
+   libelf@0.8.13%intel@15.0.0 arch=chaos_5_x86_64_ib
 
 You can either type the ``spack load`` command again with a fully
 qualified argument, or you can add just enough extra constraints to
@@ -1282,7 +1351,7 @@ You can find extensions for your Python installation like this:
 .. code-block:: sh
 
    $ spack extensions python
-   ==> python@2.7.8%gcc@4.4.7=chaos_5_x86_64_ib-703c7a96
+   ==> python@2.7.8%gcc@4.4.7 arch=chaos_5_x86_64_ib-703c7a96
    ==> 36 extensions:
    geos          py-ipython     py-pexpect    py-pyside            py-sip
    py-basemap    py-libxml2     py-pil        py-pytz              py-six
@@ -1372,9 +1441,9 @@ installation:
 .. code-block:: sh
 
    $ spack activate py-numpy
-   ==> Activated extension py-setuptools@11.3.1%gcc@4.4.7=chaos_5_x86_64_ib-3c74eb69 for python@2.7.8%gcc@4.4.7.
-   ==> Activated extension py-nose@1.3.4%gcc@4.4.7=chaos_5_x86_64_ib-5f70f816 for python@2.7.8%gcc@4.4.7.
-   ==> Activated extension py-numpy@1.9.1%gcc@4.4.7=chaos_5_x86_64_ib-66733244 for python@2.7.8%gcc@4.4.7.
+   ==> Activated extension py-setuptools@11.3.1%gcc@4.4.7 arch=chaos_5_x86_64_ib-3c74eb69 for python@2.7.8%gcc@4.4.7.
+   ==> Activated extension py-nose@1.3.4%gcc@4.4.7 arch=chaos_5_x86_64_ib-5f70f816 for python@2.7.8%gcc@4.4.7.
+   ==> Activated extension py-numpy@1.9.1%gcc@4.4.7 arch=chaos_5_x86_64_ib-66733244 for python@2.7.8%gcc@4.4.7.
 
 Several things have happened here.  The user requested that
 ``py-numpy`` be activated in the ``python`` installation it was built
@@ -1389,7 +1458,7 @@ packages listed as activated:
 .. code-block:: sh
 
    $ spack extensions python
-   ==> python@2.7.8%gcc@4.4.7=chaos_5_x86_64_ib-703c7a96
+   ==> python@2.7.8%gcc@4.4.7  arch=chaos_5_x86_64_ib-703c7a96
    ==> 36 extensions:
    geos          py-ipython     py-pexpect    py-pyside            py-sip
    py-basemap    py-libxml2     py-pil        py-pytz              py-six
@@ -1437,7 +1506,7 @@ dependencies, you can use ``spack activate -f``:
 .. code-block:: sh
 
    $ spack activate -f py-numpy
-   ==> Activated extension py-numpy@1.9.1%gcc@4.4.7=chaos_5_x86_64_ib-66733244 for python@2.7.8%gcc@4.4.7.
+   ==> Activated extension py-numpy@1.9.1%gcc@4.4.7 arch=chaos_5_x86_64_ib-66733244 for python@2.7.8%gcc@4.4.7.
 
 .. _spack-deactivate:
 
diff --git a/lib/spack/docs/configuration.rst b/lib/spack/docs/configuration.rst
index c0b79a7f44..c613071c65 100644
--- a/lib/spack/docs/configuration.rst
+++ b/lib/spack/docs/configuration.rst
@@ -70,9 +70,9 @@ directory. Here's an example of an external configuration:
    packages:
       openmpi:
          paths:
-            openmpi@1.4.3%gcc@4.4.7=chaos_5_x86_64_ib: /opt/openmpi-1.4.3
-            openmpi@1.4.3%gcc@4.4.7=chaos_5_x86_64_ib+debug: /opt/openmpi-1.4.3-debug
-            openmpi@1.6.5%intel@10.1=chaos_5_x86_64_ib: /opt/openmpi-1.6.5-intel
+            openmpi@1.4.3%gcc@4.4.7 arch=chaos_5_x86_64_ib: /opt/openmpi-1.4.3
+            openmpi@1.4.3%gcc@4.4.7 arch=chaos_5_x86_64_ib+debug: /opt/openmpi-1.4.3-debug
+            openmpi@1.6.5%intel@10.1 arch=chaos_5_x86_64_ib: /opt/openmpi-1.6.5-intel
 
 This example lists three installations of OpenMPI, one built with gcc,
 one built with gcc and debug information, and another built with Intel.
@@ -108,9 +108,9 @@ be:
   packages:
     openmpi:
       paths:
-        openmpi@1.4.3%gcc@4.4.7=chaos_5_x86_64_ib: /opt/openmpi-1.4.3
-        openmpi@1.4.3%gcc@4.4.7=chaos_5_x86_64_ib+debug: /opt/openmpi-1.4.3-debug
-        openmpi@1.6.5%intel@10.1=chaos_5_x86_64_ib: /opt/openmpi-1.6.5-intel
+        openmpi@1.4.3%gcc@4.4.7 arch=chaos_5_x86_64_ib: /opt/openmpi-1.4.3
+        openmpi@1.4.3%gcc@4.4.7 arch=chaos_5_x86_64_ib+debug: /opt/openmpi-1.4.3-debug
+        openmpi@1.6.5%intel@10.1 arch=chaos_5_x86_64_ib: /opt/openmpi-1.6.5-intel
       buildable: False
 
 The addition of the ``buildable`` flag tells Spack that it should never build
diff --git a/lib/spack/docs/features.rst b/lib/spack/docs/features.rst
index 0998ba8da4..27a3b4b435 100644
--- a/lib/spack/docs/features.rst
+++ b/lib/spack/docs/features.rst
@@ -31,14 +31,21 @@ platform, all on the command line.
    # Specify a compiler (and its version), with %
    $ spack install mpileaks@1.1.2 %gcc@4.7.3
 
-   # Add special compile-time options with +
+   # Add special compile-time options by name
+   $ spack install mpileaks@1.1.2 %gcc@4.7.3 debug=True
+
+   # Add special boolean compile-time options with +
    $ spack install mpileaks@1.1.2 %gcc@4.7.3 +debug
 
-   # Cross-compile for a different architecture with =
-   $ spack install mpileaks@1.1.2 =bgqos_0
+   # Add compiler flags using the conventional names
+   $ spack install mpileaks@1.1.2 %gcc@4.7.3 cppflags=\"-O3 -floop-block\"
+
+   # Cross-compile for a different architecture with arch=
+   $ spack install mpileaks@1.1.2 arch=bgqos_0
 
-Users can specify as many or few options as they care about.  Spack
-will fill in the unspecified values with sensible defaults.
+Users can specify as many or few options as they care about. Spack
+will fill in the unspecified values with sensible defaults. The two listed
+syntaxes for variants are identical when the value is boolean.
 
 
 Customize dependencies
diff --git a/lib/spack/docs/packaging_guide.rst b/lib/spack/docs/packaging_guide.rst
index 63c411ffb5..1f83f611b0 100644
--- a/lib/spack/docs/packaging_guide.rst
+++ b/lib/spack/docs/packaging_guide.rst
@@ -1221,11 +1221,13 @@ just as easily provide a version range:
 
    depends_on("libelf@0.8.2:0.8.4:")
 
-Or a requirement for a particular variant:
+Or a requirement for a particular variant or compiler flags:
 
 .. code-block:: python
 
    depends_on("libelf@0.8+debug")
+   depends_on('libelf debug=True')
+   depends_on('libelf cppflags="-fPIC")
 
 Both users *and* package authors can use the same spec syntax to refer
 to different package configurations.  Users use the spec syntax on the
@@ -1623,21 +1625,21 @@ the user runs ``spack install`` and the time the ``install()`` method
 is called.  The concretized version of the spec above might look like
 this::
 
-   mpileaks@2.3%gcc@4.7.3=linux-ppc64
-       ^callpath@1.0%gcc@4.7.3+debug=linux-ppc64
-           ^dyninst@8.1.2%gcc@4.7.3=linux-ppc64
-               ^libdwarf@20130729%gcc@4.7.3=linux-ppc64
-                   ^libelf@0.8.11%gcc@4.7.3=linux-ppc64
-           ^mpich@3.0.4%gcc@4.7.3=linux-ppc64
+   mpileaks@2.3%gcc@4.7.3 arch=linux-ppc64
+       ^callpath@1.0%gcc@4.7.3+debug arch=linux-ppc64
+           ^dyninst@8.1.2%gcc@4.7.3 arch=linux-ppc64
+               ^libdwarf@20130729%gcc@4.7.3 arch=linux-ppc64
+                   ^libelf@0.8.11%gcc@4.7.3 arch=linux-ppc64
+           ^mpich@3.0.4%gcc@4.7.3 arch=linux-ppc64
 
 .. graphviz::
 
    digraph {
-       "mpileaks@2.3\n%gcc@4.7.3\n=linux-ppc64" -> "mpich@3.0.4\n%gcc@4.7.3\n=linux-ppc64"
-       "mpileaks@2.3\n%gcc@4.7.3\n=linux-ppc64" -> "callpath@1.0\n%gcc@4.7.3+debug\n=linux-ppc64" -> "mpich@3.0.4\n%gcc@4.7.3\n=linux-ppc64"
-       "callpath@1.0\n%gcc@4.7.3+debug\n=linux-ppc64" -> "dyninst@8.1.2\n%gcc@4.7.3\n=linux-ppc64"
-       "dyninst@8.1.2\n%gcc@4.7.3\n=linux-ppc64" -> "libdwarf@20130729\n%gcc@4.7.3\n=linux-ppc64" -> "libelf@0.8.11\n%gcc@4.7.3\n=linux-ppc64"
-       "dyninst@8.1.2\n%gcc@4.7.3\n=linux-ppc64" -> "libelf@0.8.11\n%gcc@4.7.3\n=linux-ppc64"
+       "mpileaks@2.3\n%gcc@4.7.3\n arch=linux-ppc64" -> "mpich@3.0.4\n%gcc@4.7.3\n arch=linux-ppc64"
+       "mpileaks@2.3\n%gcc@4.7.3\n arch=linux-ppc64" -> "callpath@1.0\n%gcc@4.7.3+debug\n arch=linux-ppc64" -> "mpich@3.0.4\n%gcc@4.7.3\n arch=linux-ppc64"
+       "callpath@1.0\n%gcc@4.7.3+debug\n arch=linux-ppc64" -> "dyninst@8.1.2\n%gcc@4.7.3\n arch=linux-ppc64"
+       "dyninst@8.1.2\n%gcc@4.7.3\n arch=linux-ppc64" -> "libdwarf@20130729\n%gcc@4.7.3\n arch=linux-ppc64" -> "libelf@0.8.11\n%gcc@4.7.3\n arch=linux-ppc64"
+       "dyninst@8.1.2\n%gcc@4.7.3\n arch=linux-ppc64" -> "libelf@0.8.11\n%gcc@4.7.3\n arch=linux-ppc64"
    }
 
 Here, all versions, compilers, and platforms are filled in, and there
@@ -1666,9 +1668,9 @@ running ``spack spec``.  For example:
        ^libdwarf
            ^libelf
 
-   dyninst@8.0.1%gcc@4.7.3=linux-ppc64
-       ^libdwarf@20130729%gcc@4.7.3=linux-ppc64
-           ^libelf@0.8.13%gcc@4.7.3=linux-ppc64
+   dyninst@8.0.1%gcc@4.7.3 arch=linux-ppc64
+       ^libdwarf@20130729%gcc@4.7.3 arch=linux-ppc64
+           ^libelf@0.8.13%gcc@4.7.3 arch=linux-ppc64
 
 This is useful when you want to know exactly what Spack will do when
 you ask for a particular spec.
@@ -1908,6 +1910,12 @@ the command line.
     ``$rpath_flag`` can be overriden on a compiler specific basis in
     ``lib/spack/spack/compilers/$compiler.py``.
 
+The compiler wrappers also pass the compiler flags specified by the user from
+the command line (``cflags``, ``cxxflags``, ``fflags``, ``cppflags``, ``ldflags``,
+and/or ``ldlibs``). They do not override the canonical autotools flags with the
+same names (but in ALL-CAPS) that may be passed into the build by particularly
+challenging package scripts.
+
 Compiler flags
 ~~~~~~~~~~~~~~
 In rare circumstances such as compiling and running small unit tests, a package
@@ -2154,12 +2162,12 @@ example:
        def install(self, prefix):
            # Do default install
 
-       @when('=chaos_5_x86_64_ib')
+       @when('arch=chaos_5_x86_64_ib')
        def install(self, prefix):
            # This will be executed instead of the default install if
            # the package's sys_type() is chaos_5_x86_64_ib.
 
-       @when('=bgqos_0")
+       @when('arch=bgqos_0")
        def install(self, prefix):
            # This will be executed if the package's sys_type is bgqos_0
 
@@ -2749,11 +2757,11 @@ build it:
    $ spack stage libelf
    ==> Trying to fetch from http://www.mr511.de/software/libelf-0.8.13.tar.gz
    ######################################################################## 100.0%
-   ==> Staging archive: /Users/gamblin2/src/spack/var/spack/stage/libelf@0.8.13%gcc@4.8.3=linux-ppc64/libelf-0.8.13.tar.gz
-   ==> Created stage in /Users/gamblin2/src/spack/var/spack/stage/libelf@0.8.13%gcc@4.8.3=linux-ppc64.
+   ==> Staging archive: /Users/gamblin2/src/spack/var/spack/stage/libelf@0.8.13%gcc@4.8.3 arch=linux-ppc64/libelf-0.8.13.tar.gz
+   ==> Created stage in /Users/gamblin2/src/spack/var/spack/stage/libelf@0.8.13%gcc@4.8.3 arch=linux-ppc64.
    $ spack cd libelf
    $ pwd
-   /Users/gamblin2/src/spack/var/spack/stage/libelf@0.8.13%gcc@4.8.3=linux-ppc64/libelf-0.8.13
+   /Users/gamblin2/src/spack/var/spack/stage/libelf@0.8.13%gcc@4.8.3 arch=linux-ppc64/libelf-0.8.13
 
 ``spack cd`` here changed he current working directory to the
 directory containing the expanded ``libelf`` source code.  There are a