diff --git a/.appveyor.yml b/.appveyor.yml
index b280f1d86..35251ffc6 100644
--- a/.appveyor.yml
+++ b/.appveyor.yml
@@ -5,16 +5,20 @@ os: Visual Studio 2015
 
 install:
     - set PATH=C:\msys64\usr\bin;%PATH%
+    - set MSYSTEM=MINGW64
     - bash -lc ""
     - bash -lc "pacman --noconfirm --needed -Sy bash pacman pacman-mirrors msys2-runtime msys2-runtime-devel"
     # we don't actually need ada, fortran, libgfortran, or objc, but in
     # order to update gcc we need to also update those packages as well...
     - bash -lc "pacman --noconfirm -S mingw-w64-x86_64-{gcc,gcc-ada,gcc-fortran,gcc-libgfortran,gcc-objc,cmake,make,icu,jemalloc,zlib}"
 before_build:
+    - set MSYSTEM=MINGW64
     - cd C:\projects\meta
     - git submodule update --init --recursive
     - bash -lc "export PATH=/mingw64/bin:$PATH && cd $APPVEYOR_BUILD_FOLDER && mkdir build && cd build && cmake .. -G \"MSYS Makefiles\""
 build_script:
-    - bash -lc "export PATH=/mingw64/bin:$PATH && cd $APPVEYOR_BUILD_FOLDER/build && make"
+    - set MSYSTEM=MINGW64
+    - bash -lc "export PATH=/mingw64/bin:$PATH && cd $APPVEYOR_BUILD_FOLDER/build && make -j2"
 test_script:
+    - set MSYSTEM=MINGW64
     - bash -lc "export PATH=/mingw64/bin:$PATH && cd $APPVEYOR_BUILD_FOLDER/build && cp ../config.toml . && ./unit-test --reporter=spec"
diff --git a/.travis.yml b/.travis.yml
index 071c06c40..412cff95b 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -5,6 +5,10 @@ language: cpp
 
 sudo: false
 
+cache:
+  directories:
+    deps/icu
+
 addons:
   apt:
     packages: &default-packages
@@ -49,6 +53,18 @@ matrix:
             - gcc-5
             - g++-5
 
+    # Linux/GCC 6
+    - os: linux
+      env: COMPILER=gcc GCC_VERSION=6
+      addons:
+        apt:
+          sources:
+            - ubuntu-toolchain-r-test
+          packages:
+            - *default-packages
+            - gcc-6
+            - g++-6
+
     # Linux/Clang 3.6
     - os: linux
       env: COMPILER=clang CLANG_VERSION=3.6
@@ -81,7 +97,7 @@ matrix:
       osx_image: xcode7.2
       env: COMPILER=clang
 
-    # OS X/GCC 5
+    # OS X/GCC 6
     - os: osx
       env: COMPILER=gcc
 
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 13ae6fa26..4779eaf59 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,57 @@
+# [v2.3.0][2.3.0]
+## New features
+- Forward and inverted indexes are now stored in one directory. **To make
+    use of your existing indexes, you will need to move their
+    directories.** For example, a configuration that used to look like the
+    following
+
+    ```toml
+    dataset = "20newsgroups"
+    corpus = "line.toml"
+    forward-index = "20news-fwd"
+    inverted-index = "20news-inv"
+    ```
+
+    will now look like the following
+
+    ```toml
+    dataset = "20newsgroups"
+    corpus = "line.toml"
+    index = "20news-index"
+    ```
+
+    and your folder structure should now look like
+
+    ```
+    20news-index
+    ├── fwd
+    └── inv
+    ```
+
+    You can do this by simply moving the old folders around like so:
+
+    ```bash
+    mkdir 20news-index
+    mv 20news-fwd 20news-index/fwd
+    mv 20news-inv 20news-index/inv
+    ```
+- `stats::multinomial` now can report the number of unique event types
+    counted (`unique_events()`)
+- `std::vector` can now be hashed via `hash_append`.
+
+## Bug fixes
+- Fix rounding bug in language model-based rankers. This bug caused
+    severely degraded performance for these rankers with short queries. The
+    unit tests have been improved to prevent such a regression in the
+    future.
+
+## Enhancements
+- The bundled ICU version has been bumped to ICU 57.1.
+- MeTA will now attempt to build its own version of ICU on Windows if it
+    fails to find a suitable ICU installed.
+- CI support for GCC 6.x was added for all three major platforms.
+- CI support also uses a fixed version of LLVM/libc++ instead of trunk.
+
 # [v2.2.0][2.2.0]
 ## New features
 - Parallelized versions of PageRank and Personalized PageRank have been
@@ -381,7 +435,8 @@
 # [v1.0][1.0]
 - Initial release.
 
-[unreleased]: https://github.com/meta-toolkit/meta/compare/v2.2.0...develop
+[unreleased]: https://github.com/meta-toolkit/meta/compare/v2.3.0...develop
+[2.3.0]: https://github.com/meta-toolkit/meta/compare/v2.2.0...v2.3.0
 [2.2.0]: https://github.com/meta-toolkit/meta/compare/v2.1.0...v2.2.0
 [2.1.0]: https://github.com/meta-toolkit/meta/compare/v2.0.1...v2.1.0
 [2.0.1]: https://github.com/meta-toolkit/meta/compare/v2.0.0...v2.0.1
diff --git a/CMakeLists.txt b/CMakeLists.txt
index e9d799c3a..e1cedc627 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -41,9 +41,9 @@ list(APPEND CMAKE_MODULE_PATH ${CMAKE_CURRENT_SOURCE_DIR}/deps/meta-cmake/)
 
 # We require Unicode 8 for the unit tests, which was added in ICU 56.1
 FindOrBuildICU(
-  VERSION 56.1
-  URL http://download.icu-project.org/files/icu4c/56.1/icu4c-56_1-src.tgz
-  URL_HASH MD5=c4a2d71ff56aec5ebfab2a3f059be99d
+  VERSION 57.1
+  URL http://download.icu-project.org/files/icu4c/57.1/icu4c-57_1-src.tgz
+  URL_HASH MD5=976734806026a4ef8bdd17937c8898b9
 )
 
 add_library(meta-definitions INTERFACE)
@@ -54,7 +54,7 @@ if(UNIX OR MINGW)
   target_compile_options(meta-definitions INTERFACE -Wall -Wextra -pedantic)
 
   if (CMAKE_CXX_COMPILER_ID MATCHES "Clang")
-    SetClangOptions()
+    SetClangOptions(meta-definitions)
   endif()
 endif()
 
diff --git a/STYLE.md b/STYLE.md
index c429a91d8..38da6d985 100644
--- a/STYLE.md
+++ b/STYLE.md
@@ -30,7 +30,7 @@ void myclass::member(const type&);
 - Prefer `enum class` (strongly typed `enum`s).
 - Prefer no pointer over `unique_ptr` over `shared_ptr`.
 - Do not use `rand()` [deprecated in
-  C++14](www.open-std.org/jtc1/sc22/wg21/docs/papers/2014/n3841.pdf).
+  C++14](http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2014/n3841.pdf).
 - Use `#ifndef META_FILE_NAME_H_` for double inclusion guards.
 - `#define` kept to a minimum, and ALL_CAPS_SNAKE if used.
 - Lines should be no longer than 80 characters
diff --git a/config.toml b/config.toml
index 82b6d1b57..1b3f5987b 100644
--- a/config.toml
+++ b/config.toml
@@ -10,8 +10,7 @@ query-path = "../queries.txt" # create this file
 
 dataset = "ceeaus"
 corpus = "line.toml" # located inside dataset folder
-forward-index = "ceeaus-fwd"
-inverted-index = "ceeaus-inv"
+index = "ceeaus"
 indexer-ram-budget = 1024 # **estimated** RAM budget for indexing in MB
                           # always set this lower than your physical RAM!
 # indexer-num-threads = 8 # default value is system thread concurrency
@@ -32,7 +31,6 @@ method = "one-vs-all"
 [classifier.base]
 method = "sgd"
 loss = "hinge"
-prefix = "sgd-model"
 
 [lda]
 inference = "gibbs"
diff --git a/deps/meta-cmake b/deps/meta-cmake
index fa6cdb474..bafbe8112 160000
--- a/deps/meta-cmake
+++ b/deps/meta-cmake
@@ -1 +1 @@
-Subproject commit fa6cdb474edeae25d0ffafc44458583e39412d39
+Subproject commit bafbe81127faab9679fb7bfdb9f81c2d60d3f74a
diff --git a/deps/meta-stlsoft b/deps/meta-stlsoft
index 2fe7ee921..586c4fe84 160000
--- a/deps/meta-stlsoft
+++ b/deps/meta-stlsoft
@@ -1 +1 @@
-Subproject commit 2fe7ee9211bfd1b6b4d15adc99e13aacacc5f5a2
+Subproject commit 586c4fe84e8d822d1581f04d006f9b86ae75b8bb
diff --git a/include/meta/corpus/corpus.h b/include/meta/corpus/corpus.h
index d14565405..3ea7c309a 100644
--- a/include/meta/corpus/corpus.h
+++ b/include/meta/corpus/corpus.h
@@ -78,7 +78,7 @@ class corpus
     /**
      * @return the corpus' metadata schema
      */
-    virtual metadata::schema schema() const;
+    virtual metadata::schema_type schema() const;
 
     /**
      * Destructor.
diff --git a/include/meta/corpus/file_corpus.h b/include/meta/corpus/file_corpus.h
index f3b3ca9d4..d56943e44 100644
--- a/include/meta/corpus/file_corpus.h
+++ b/include/meta/corpus/file_corpus.h
@@ -58,7 +58,7 @@ class file_corpus : public corpus
     /**
      * @return the metadata schema for this corpus
      */
-    metadata::schema schema() const override;
+    metadata::schema_type schema() const override;
 
   private:
     /// the current document we are on
diff --git a/include/meta/corpus/libsvm_corpus.h b/include/meta/corpus/libsvm_corpus.h
index f4fd77924..3cfb8f285 100644
--- a/include/meta/corpus/libsvm_corpus.h
+++ b/include/meta/corpus/libsvm_corpus.h
@@ -55,7 +55,7 @@ class libsvm_corpus : public corpus
 
     uint64_t size() const override;
 
-    metadata::schema schema() const override;
+    metadata::schema_type schema() const override;
 
   private:
     /// The current document we are on
diff --git a/include/meta/corpus/metadata.h b/include/meta/corpus/metadata.h
index 38476ca3d..8f2e4c4e5 100644
--- a/include/meta/corpus/metadata.h
+++ b/include/meta/corpus/metadata.h
@@ -62,9 +62,9 @@ class metadata
 
     // I want the below to be a const field_info, but g++ gives a cryptic
     // compiler error in that case... clang++ accepts it just fine. -sigh-
-    using schema = std::vector<field_info>;
+    using schema_type = std::vector<field_info>;
 
-    metadata(const char* start, const schema& sch)
+    metadata(const char* start, const schema_type& sch)
         : schema_{&sch}, start_{start}
     {
         // nothing
@@ -124,6 +124,14 @@ class metadata
         return util::nullopt;
     }
 
+    /**
+     * Returns the schema for this metadata object.
+     */
+    const schema_type& schema() const
+    {
+        return *schema_;
+    }
+
     /**
      * Tagged union to represent a single metadata field.
      */
@@ -303,7 +311,7 @@ class metadata
     };
 
     /// pointer to the metadata_file's schema
-    const schema* schema_;
+    const schema_type* schema_;
 
     /// the start of the metadata within the metadata_file
     const char* start_;
@@ -314,7 +322,7 @@ class metadata
  * @param config The configuration group that specifies the metadata
  * @return the corresponding metadata::schema object.
  */
-metadata::schema metadata_schema(const cpptoml::table& config);
+metadata::schema_type metadata_schema(const cpptoml::table& config);
 
 /**
  * Exception class for metadata operations.
diff --git a/include/meta/corpus/metadata_parser.h b/include/meta/corpus/metadata_parser.h
index 2fd4ed3e9..3f139362d 100644
--- a/include/meta/corpus/metadata_parser.h
+++ b/include/meta/corpus/metadata_parser.h
@@ -32,7 +32,7 @@ class metadata_parser
      * @param filename The name of the file to parse
      * @param schema The schema to parse the file with
      */
-    metadata_parser(const std::string& filename, metadata::schema schema);
+    metadata_parser(const std::string& filename, metadata::schema_type schema);
 
     /**
      * @return the metadata vector for the next document in the file
@@ -42,14 +42,14 @@ class metadata_parser
     /**
      * @return the schema for the metadata in this file
      */
-    const metadata::schema& schema() const;
+    const metadata::schema_type& schema() const;
 
   private:
     /// the parser used to extract metadata
     io::mifstream infile_;
 
     /// the schema for the metadata being extracted
-    metadata::schema schema_;
+    metadata::schema_type schema_;
 };
 }
 }
diff --git a/include/meta/hashing/hash.h b/include/meta/hashing/hash.h
index 9b5d44aff..030423f9f 100644
--- a/include/meta/hashing/hash.h
+++ b/include/meta/hashing/hash.h
@@ -181,6 +181,14 @@ template <class HashAlgorithm, class T1, class T2, class... Ts>
 void hash_append(HashAlgorithm& h, const T1& first, const T2& second,
                  const Ts&... ts);
 
+template <class HashAlgorithm, class T, class Alloc>
+typename std::enable_if<is_contiguously_hashable<T>::value>::type
+hash_append(HashAlgorithm& h, const std::vector<T, Alloc>& v);
+
+template <class HashAlgorithm, class T, class Alloc>
+typename std::enable_if<!is_contiguously_hashable<T>::value>::type
+hash_append(HashAlgorithm& h, const std::vector<T, Alloc>& v);
+
 // begin implementations for hash_append
 
 template <class HashAlgorithm, class T, std::size_t N>
@@ -258,6 +266,23 @@ hash_append(HashAlgorithm& h, const std::basic_string<Char, Traits, Alloc>& s)
     hash_append(h, s.size());
 }
 
+template <class HashAlgorithm, class T, class Alloc>
+typename std::enable_if<is_contiguously_hashable<T>::value>::type
+hash_append(HashAlgorithm& h, const std::vector<T, Alloc>& v)
+{
+    h(v.data(), v.size() * sizeof(T));
+    hash_append(h, v.size());
+}
+
+template <class HashAlgorithm, class T, class Alloc>
+typename std::enable_if<!is_contiguously_hashable<T>::value>::type
+hash_append(HashAlgorithm& h, const std::vector<T, Alloc>& v)
+{
+    for (const auto& val : v)
+        hash_append(h, val);
+    hash_append(h, v.size());
+}
+
 template <class HashAlgorithm, class T1, class T2, class... Ts>
 void hash_append(HashAlgorithm& h, const T1& first, const T2& second,
                  const Ts&... ts)
diff --git a/include/meta/index/disk_index.h b/include/meta/index/disk_index.h
index 7fcf38b84..bece0e476 100644
--- a/include/meta/index/disk_index.h
+++ b/include/meta/index/disk_index.h
@@ -31,11 +31,6 @@ class string_list;
 class vocabulary_map;
 }
 
-namespace tokenizers
-{
-class tokenizer;
-}
-
 namespace util
 {
 template <class>
diff --git a/include/meta/index/make_index.h b/include/meta/index/make_index.h
index 8a67d8fbe..394fe89dd 100644
--- a/include/meta/index/make_index.h
+++ b/include/meta/index/make_index.h
@@ -61,22 +61,10 @@ template <class Index, class... Args>
 std::shared_ptr<Index> make_index(const cpptoml::table& config,
                                   corpus::corpus& docs, Args&&... args)
 {
-    // check if we have paths specified for either kind of index
-    if (!(config.contains("forward-index")
-          && config.contains("inverted-index")))
+    if (!config.contains("index"))
     {
         throw typename Index::exception{
-            "forward-index or inverted-index missing from configuration file"};
-    }
-
-    // make sure that the index names are different!
-    auto fwd_name = config.get_as<std::string>("forward-index");
-    auto inv_name = config.get_as<std::string>("inverted-index");
-
-    if (*fwd_name == *inv_name)
-    {
-        throw typename Index::exception{
-            "forward and inverted index names must be different!"};
+            "index name missing from configuration file"};
     }
 
     // below is needed so that make_shared can find a public ctor to invoke
@@ -88,6 +76,7 @@ std::shared_ptr<Index> make_index(const cpptoml::table& config,
             // nothing
         }
     };
+
     auto idx = std::make_shared<make_shared_enabler>(
         config, std::forward<Args>(args)...);
 
@@ -98,8 +87,7 @@ std::shared_ptr<Index> make_index(const cpptoml::table& config,
     }
     else
     {
-        if (!filesystem::exists(idx->index_name()))
-            filesystem::make_directory(idx->index_name());
+        filesystem::remove_all(idx->index_name());
         idx->create_index(config, docs);
     }
 
@@ -112,23 +100,10 @@ std::shared_ptr<Index> make_index(const cpptoml::table& config,
 template <class Index, class... Args>
 std::shared_ptr<Index> make_index(const cpptoml::table& config, Args&&... args)
 {
-
-    // check if we have paths specified for either kind of index
-    if (!(config.contains("forward-index")
-          && config.contains("inverted-index")))
+    if (!config.contains("index"))
     {
         throw typename Index::exception{
-            "forward-index or inverted-index missing from configuration file"};
-    }
-
-    // make sure that the index names are different!
-    auto fwd_name = config.get_as<std::string>("forward-index");
-    auto inv_name = config.get_as<std::string>("inverted-index");
-
-    if (*fwd_name == *inv_name)
-    {
-        throw typename Index::exception{
-            "forward and inverted index names must be different!"};
+            "index name missing from configuration file"};
     }
 
     // below is needed so that make_shared can find a public ctor to invoke
@@ -140,6 +115,7 @@ std::shared_ptr<Index> make_index(const cpptoml::table& config, Args&&... args)
             // nothing
         }
     };
+
     auto idx = std::make_shared<make_shared_enabler>(
         config, std::forward<Args>(args)...);
 
@@ -150,9 +126,7 @@ std::shared_ptr<Index> make_index(const cpptoml::table& config, Args&&... args)
     }
     else
     {
-        if (!filesystem::exists(idx->index_name()))
-            filesystem::make_directory(idx->index_name());
-
+        filesystem::remove_all(idx->index_name());
         auto docs = corpus::make_corpus(config);
         idx->create_index(config, *docs);
     }
diff --git a/include/meta/index/metadata_file.h b/include/meta/index/metadata_file.h
index 87f1bb40d..350fbeede 100644
--- a/include/meta/index/metadata_file.h
+++ b/include/meta/index/metadata_file.h
@@ -72,7 +72,7 @@ class metadata_file
 
   private:
     /// the schema for this file
-    corpus::metadata::schema schema_;
+    corpus::metadata::schema_type schema_;
 
     /// the seek positions for every document in this file
     util::disk_vector<uint64_t> index_;
diff --git a/include/meta/index/metadata_writer.h b/include/meta/index/metadata_writer.h
index e0d596252..416ff38c8 100644
--- a/include/meta/index/metadata_writer.h
+++ b/include/meta/index/metadata_writer.h
@@ -33,7 +33,7 @@ class metadata_writer
      * @param schema The schema for the metadata we will store
      */
     metadata_writer(const std::string& prefix, uint64_t num_docs,
-                    corpus::metadata::schema schema);
+                    corpus::metadata::schema_type schema);
 
     /**
      * Writes a document's metadata to the database and index.
@@ -59,7 +59,7 @@ class metadata_writer
     std::ofstream db_file_;
 
     /// the schema of the metadata we are writing
-    corpus::metadata::schema schema_;
+    corpus::metadata::schema_type schema_;
 };
 }
 }
diff --git a/include/meta/io/filesystem.h b/include/meta/io/filesystem.h
index ef5e6704d..1a04719e4 100644
--- a/include/meta/io/filesystem.h
+++ b/include/meta/io/filesystem.h
@@ -53,6 +53,13 @@ void rename_file(const std::string& old_name, const std::string& new_name);
  */
 bool make_directory(const std::string& dir_name);
 
+/**
+ * Attempts to create the directory and any other directories in the path
+ * @param path The path to the new directory
+ * @return whether a new directory was created
+ */
+bool make_directories(const std::string& path);
+
 /**
  * @param filename The file to check
  * @return true if the file exists
diff --git a/include/meta/stats/multinomial.h b/include/meta/stats/multinomial.h
index aa3fd7a7a..d4c8200a3 100644
--- a/include/meta/stats/multinomial.h
+++ b/include/meta/stats/multinomial.h
@@ -75,6 +75,11 @@ class multinomial
      */
     double counts() const;
 
+    /**
+     * @return the number of unique event values that have been observed
+     */
+    uint64_t unique_events() const;
+
     /**
      * Runs a function for each observed event for this distribution. Note
      * that this does **not** include the prior, only events that have been
diff --git a/include/meta/stats/multinomial.tcc b/include/meta/stats/multinomial.tcc
index c9fc0347a..5cd7a298d 100644
--- a/include/meta/stats/multinomial.tcc
+++ b/include/meta/stats/multinomial.tcc
@@ -54,6 +54,12 @@ double multinomial<T>::counts() const
     return total_counts_ + prior_.pseudo_counts();
 }
 
+template <class T>
+uint64_t multinomial<T>::unique_events() const
+{
+    return counts_.size();
+}
+
 template <class T>
 template <class Fun>
 void multinomial<T>::each_seen_event(Fun&& fun) const
diff --git a/src/classify/CMakeLists.txt b/src/classify/CMakeLists.txt
index 2ff9a4680..685e094a0 100644
--- a/src/classify/CMakeLists.txt
+++ b/src/classify/CMakeLists.txt
@@ -7,12 +7,16 @@ ExternalProject_Add(liblinear
   SOURCE_DIR ${meta_SOURCE_DIR}/../deps/libsvm-modules/liblinear
   BINARY_DIR ${meta_SOURCE_DIR}/../deps/libsvm-modules/liblinear/build
   CMAKE_ARGS -DCMAKE_BUILD_TYPE=Release
+  CMAKE_CACHE_ARGS "-DCMAKE_C_COMPILER:FILEPATH=${CMAKE_C_COMPILER}"
+                   "-DCMAKE_CXX_COMPILER:FILEPATH=${CMAKE_CXX_COMPILER}"
   INSTALL_COMMAND "")
 
 ExternalProject_Add(libsvm
   SOURCE_DIR ${meta_SOURCE_DIR}/../deps/libsvm-modules/libsvm
   BINARY_DIR ${meta_SOURCE_DIR}/../deps/libsvm-modules/libsvm/build
   CMAKE_ARGS -DCMAKE_BUILD_TYPE=Release
+  CMAKE_CACHE_ARGS "-DCMAKE_C_COMPILER:FILEPATH=${CMAKE_C_COMPILER}"
+                   "-DCMAKE_CXX_COMPILER:FILEPATH=${CMAKE_CXX_COMPILER}"
   INSTALL_COMMAND "")
 
 add_library(meta-classify binary_classifier_factory.cpp
diff --git a/src/classify/confusion_matrix.cpp b/src/classify/confusion_matrix.cpp
index ff0bd4e58..78f81c79d 100644
--- a/src/classify/confusion_matrix.cpp
+++ b/src/classify/confusion_matrix.cpp
@@ -187,19 +187,22 @@ void confusion_matrix::print_stats(std::ostream& out) const
         = std::setw(static_cast<int>(width + printing::make_bold("").size()));
     auto w2 = std::setw(static_cast<int>(12 + printing::make_bold("").size()));
     out.precision(3);
-    out << std::string(width + 12 * 3, '-') << std::endl
+    out << std::string(width + 12 * 4, '-') << std::endl
         << std::left << w1 << printing::make_bold("Class") << std::left << w2
         << printing::make_bold("F1 Score") << std::left << w2
         << printing::make_bold("Precision") << std::left << w2
-        << printing::make_bold("Recall") << std::endl
-        << std::string(width + 12 * 3, '-') << std::endl;
+        << printing::make_bold("Recall") << std::left << w2
+        << printing::make_bold("Class Dist") << std::endl
+        << std::string(width + 12 * 4, '-') << std::endl;
 
     for (auto& cls : classes_)
     {
         auto w3 = std::setw(12); // different width for non-bold
         out << std::left << std::setw(static_cast<int>(width)) << cls
             << std::left << w3 << f1_score(cls) << std::left << w3
-            << precision(cls) << std::left << w3 << recall(cls) << std::endl;
+            << precision(cls) << std::left << w3 << recall(cls)
+            << std::left << w3 << static_cast<double>(counts_.at(cls)) / total_
+            << std::endl;
     }
 
     auto limit = [](double val)
@@ -210,12 +213,12 @@ void confusion_matrix::print_stats(std::ostream& out) const
         return ss.str();
     };
 
-    out << std::string(width + 12 * 3, '-') << std::endl
+    out << std::string(width + 12 * 4, '-') << std::endl
         << w1 << printing::make_bold("Total") << w2
         << printing::make_bold(limit(f1_score())) << w2
         << printing::make_bold(limit(precision())) << w2
         << printing::make_bold(limit(recall())) << std::endl
-        << std::string(width + 12 * 3, '-') << std::endl
+        << std::string(width + 12 * 4, '-') << std::endl
         << total_ << " predictions attempted, overall accuracy: " << accuracy()
         << std::endl;
 
diff --git a/src/corpus/corpus.cpp b/src/corpus/corpus.cpp
index 0073a7f7e..915545e1b 100644
--- a/src/corpus/corpus.cpp
+++ b/src/corpus/corpus.cpp
@@ -25,7 +25,7 @@ std::vector<metadata::field> corpus::next_metadata()
     return mdata_parser_->next();
 }
 
-metadata::schema corpus::schema() const
+metadata::schema_type corpus::schema() const
 {
     auto schema = mdata_parser_->schema();
     if (store_full_text())
diff --git a/src/corpus/file_corpus.cpp b/src/corpus/file_corpus.cpp
index 87c4c1750..0238fa742 100644
--- a/src/corpus/file_corpus.cpp
+++ b/src/corpus/file_corpus.cpp
@@ -78,7 +78,7 @@ uint64_t file_corpus::size() const
     return docs_.size();
 }
 
-metadata::schema file_corpus::schema() const
+metadata::schema_type file_corpus::schema() const
 {
     auto schema = corpus::schema();
     schema.insert(schema.begin(),
diff --git a/src/corpus/libsvm_corpus.cpp b/src/corpus/libsvm_corpus.cpp
index a6bca8604..1b4b53630 100644
--- a/src/corpus/libsvm_corpus.cpp
+++ b/src/corpus/libsvm_corpus.cpp
@@ -65,7 +65,7 @@ document libsvm_corpus::next()
     return doc;
 }
 
-metadata::schema libsvm_corpus::schema() const
+metadata::schema_type libsvm_corpus::schema() const
 {
     auto schema = corpus::schema();
     if (lbl_type_ == label_type::REGRESSION)
diff --git a/src/corpus/metadata.cpp b/src/corpus/metadata.cpp
index 08e2fd938..5479970ea 100644
--- a/src/corpus/metadata.cpp
+++ b/src/corpus/metadata.cpp
@@ -10,9 +10,9 @@ namespace meta
 namespace corpus
 {
 
-metadata::schema metadata_schema(const cpptoml::table& config)
+metadata::schema_type metadata_schema(const cpptoml::table& config)
 {
-    metadata::schema schema;
+    metadata::schema_type schema;
     if (auto metadata = config.get_table_array("metadata"))
     {
         const auto& arr = metadata->get();
diff --git a/src/corpus/metadata_parser.cpp b/src/corpus/metadata_parser.cpp
index e10e64772..1d0e0f60f 100644
--- a/src/corpus/metadata_parser.cpp
+++ b/src/corpus/metadata_parser.cpp
@@ -16,7 +16,7 @@ namespace corpus
 {
 
 metadata_parser::metadata_parser(const std::string& filename,
-                                 metadata::schema schema)
+                                 metadata::schema_type schema)
     : infile_{filename}, schema_{std::move(schema)}
 {
     // nothing
@@ -77,7 +77,7 @@ std::vector<metadata::field> metadata_parser::next()
     return mdata;
 }
 
-const metadata::schema& metadata_parser::schema() const
+const metadata::schema_type& metadata_parser::schema() const
 {
     return schema_;
 }
diff --git a/src/features/tools/CMakeLists.txt b/src/features/tools/CMakeLists.txt
index 8032b0e95..a323bec71 100644
--- a/src/features/tools/CMakeLists.txt
+++ b/src/features/tools/CMakeLists.txt
@@ -1,2 +1,3 @@
 add_executable(feature-summary feature_summary.cpp)
-target_link_libraries(feature-summary meta-features meta-index)
+target_link_libraries(feature-summary meta-features meta-index
+    meta-sequence-analyzers meta-parser-analyzers)
diff --git a/src/features/tools/feature_summary.cpp b/src/features/tools/feature_summary.cpp
index f9c9f40ba..86d7c3270 100644
--- a/src/features/tools/feature_summary.cpp
+++ b/src/features/tools/feature_summary.cpp
@@ -13,6 +13,8 @@
 #include "meta/features/selector_factory.h"
 #include "meta/index/forward_index.h"
 #include "meta/logging/logger.h"
+#include "meta/parser/analyzers/tree_analyzer.h"
+#include "meta/sequence/analyzers/ngram_pos_analyzer.h"
 #include "meta/util/shim.h"
 
 using namespace meta;
@@ -27,6 +29,10 @@ int main(int argc, char* argv[])
 
     logging::set_cerr_logging();
 
+    // Register additional analyzers
+    parser::register_analyzers();
+    sequence::register_analyzers();
+
     auto config = cpptoml::parse_file(argv[1]);
     auto feature_config = config->get_table("features");
     if (!feature_config)
diff --git a/src/index/forward_index.cpp b/src/index/forward_index.cpp
index fe49619be..6ffdef756 100644
--- a/src/index/forward_index.cpp
+++ b/src/index/forward_index.cpp
@@ -121,7 +121,7 @@ class forward_index::impl
 };
 
 forward_index::forward_index(const cpptoml::table& config)
-    : disk_index{config, *config.get_as<std::string>("forward-index")},
+    : disk_index{config, *config.get_as<std::string>("index") + "/fwd"},
       fwd_impl_{this, config}
 {
     /* nothing */
@@ -198,6 +198,9 @@ void forward_index::load_index()
 void forward_index::create_index(const cpptoml::table& config,
                                  corpus::corpus& docs)
 {
+    if (!filesystem::make_directories(index_name()))
+        throw exception{"Unable to create index directory: " + index_name()};
+
     {
         std::ofstream config_file{index_name() + "/config.toml"};
         config_file << config;
diff --git a/src/index/inverted_index.cpp b/src/index/inverted_index.cpp
index 0d1f8bd16..d5b60d1cb 100644
--- a/src/index/inverted_index.cpp
+++ b/src/index/inverted_index.cpp
@@ -87,7 +87,7 @@ inverted_index::impl::impl(inverted_index* idx, const cpptoml::table& config)
 }
 
 inverted_index::inverted_index(const cpptoml::table& config)
-    : disk_index{config, *config.get_as<std::string>("inverted-index")},
+    : disk_index{config, *config.get_as<std::string>("index") + "/inv"},
       inv_impl_{this, config}
 {
     // nothing
@@ -115,6 +115,9 @@ bool inverted_index::valid() const
 void inverted_index::create_index(const cpptoml::table& config,
                                   corpus::corpus& docs)
 {
+    if (!filesystem::make_directories(index_name()))
+        throw exception{"Unable to create index directory: " + index_name()};
+
     // save the config file so we can recreate the analyzer
     {
         std::ofstream config_file{index_name() + "/config.toml"};
diff --git a/src/index/metadata_writer.cpp b/src/index/metadata_writer.cpp
index 44ba66b32..4310ad6b8 100644
--- a/src/index/metadata_writer.cpp
+++ b/src/index/metadata_writer.cpp
@@ -12,7 +12,7 @@ namespace index
 {
 
 metadata_writer::metadata_writer(const std::string& prefix, uint64_t num_docs,
-                                 corpus::metadata::schema schema)
+                                 corpus::metadata::schema_type schema)
     : seek_pos_{prefix + "/metadata.index", num_docs},
       byte_pos_{0},
       db_file_{prefix + "/metadata.db", std::ios::binary},
diff --git a/src/index/ranker/absolute_discount.cpp b/src/index/ranker/absolute_discount.cpp
index d48ea4426..4bb2caddd 100644
--- a/src/index/ranker/absolute_discount.cpp
+++ b/src/index/ranker/absolute_discount.cpp
@@ -14,6 +14,7 @@ namespace index
 {
 
 const util::string_view absolute_discount::id = "absolute-discount";
+const constexpr float absolute_discount::default_delta;
 
 absolute_discount::absolute_discount(float delta) : delta_{delta}
 {
diff --git a/src/index/ranker/dirichlet_prior.cpp b/src/index/ranker/dirichlet_prior.cpp
index 43a4852c3..07536afbe 100644
--- a/src/index/ranker/dirichlet_prior.cpp
+++ b/src/index/ranker/dirichlet_prior.cpp
@@ -13,6 +13,7 @@ namespace index
 {
 
 const util::string_view dirichlet_prior::id = "dirichlet-prior";
+const constexpr float dirichlet_prior::default_mu;
 
 dirichlet_prior::dirichlet_prior(float mu) : mu_{mu}
 {
diff --git a/src/index/ranker/jelinek_mercer.cpp b/src/index/ranker/jelinek_mercer.cpp
index 200752d5f..46ff9440e 100644
--- a/src/index/ranker/jelinek_mercer.cpp
+++ b/src/index/ranker/jelinek_mercer.cpp
@@ -13,6 +13,7 @@ namespace index
 {
 
 const util::string_view jelinek_mercer::id = "jelinek-mercer";
+const constexpr float jelinek_mercer::default_lambda;
 
 jelinek_mercer::jelinek_mercer(float lambda) : lambda_{lambda}
 {
diff --git a/src/index/ranker/lm_ranker.cpp b/src/index/ranker/lm_ranker.cpp
index c5460ff29..dc62fed79 100644
--- a/src/index/ranker/lm_ranker.cpp
+++ b/src/index/ranker/lm_ranker.cpp
@@ -19,7 +19,7 @@ const util::string_view language_model_ranker::id = "language-model";
 float language_model_ranker::score_one(const score_data& sd)
 {
     float ps = smoothed_prob(sd);
-    float pc = sd.corpus_term_count / sd.total_terms;
+    float pc = static_cast<float>(sd.corpus_term_count) / sd.total_terms;
     return sd.query_term_weight
            * fastapprox::fastlog(ps / (doc_constant(sd) * pc));
 }
diff --git a/src/io/filesystem.cpp b/src/io/filesystem.cpp
index 8458b5fb2..f0d121d38 100644
--- a/src/io/filesystem.cpp
+++ b/src/io/filesystem.cpp
@@ -11,6 +11,7 @@
 #include <platformstl/filesystem/filesystem_traits.hpp>
 #include <platformstl/filesystem/path.hpp>
 #include <platformstl/filesystem/readdir_sequence.hpp>
+#include <platformstl/filesystem/directory_functions.hpp>
 #else
 #include <experimental/filesystem>
 #endif
@@ -47,6 +48,11 @@ bool make_directory(const std::string& dir_name)
     return traits::create_directory(dir_name.c_str());
 }
 
+bool make_directories(const std::string& path)
+{
+    return stlsoft::platformstl_project::create_directory_recurse(path);
+}
+
 bool file_exists(const std::string& filename)
 {
     return traits::file_exists(filename.c_str());
@@ -133,6 +139,11 @@ bool make_directory(const std::string& dir_name)
     return fs::create_directory(dir_name);
 }
 
+bool make_directories(const std::string& path)
+{
+    return fs::create_directories(path);
+}
+
 bool file_exists(const std::string& filename)
 {
     return fs::exists(filename);
diff --git a/tests/classifier_test.cpp b/tests/classifier_test.cpp
index 9d3db31df..48905d62b 100644
--- a/tests/classifier_test.cpp
+++ b/tests/classifier_test.cpp
@@ -194,12 +194,10 @@ void run_tests(const std::string& index_type) {
 
 go_bandit([]() {
 
-    filesystem::remove_all("ceeaus-inv");
-    filesystem::remove_all("ceeaus-fwd");
+    filesystem::remove_all("ceeaus");
     run_tests("line");
 
-    filesystem::remove_all("ceeaus-inv");
-    filesystem::remove_all("ceeaus-fwd");
+    filesystem::remove_all("ceeaus");
     run_tests("file");
 
     describe("[classifier] saving and loading model files", [&]() {
@@ -276,8 +274,7 @@ go_bandit([]() {
         });
     });
 
-    filesystem::remove_all("ceeaus-inv");
-    filesystem::remove_all("ceeaus-fwd");
+    filesystem::remove_all("ceeaus");
 
     describe("[classifier] confusion matrix", [&]() {
 
diff --git a/tests/create_config.h b/tests/create_config.h
index d0053f7bd..a78fbdb3c 100644
--- a/tests/create_config.h
+++ b/tests/create_config.h
@@ -57,8 +57,7 @@ create_config(const std::string& corpus_type, bool multi = false) {
     table->insert("dataset", "ceeaus");
     table->insert("corpus", corpus_type + ".toml");
     table->insert("encoding", "shift_jis");
-    table->insert("forward-index", "ceeaus-fwd");
-    table->insert("inverted-index", "ceeaus-inv");
+    table->insert("index", "ceeaus");
 
     auto anas = cpptoml::make_table_array();
     auto ana = cpptoml::make_table();
diff --git a/tests/feature_selection_test.cpp b/tests/feature_selection_test.cpp
index 734a74241..beda82c7b 100644
--- a/tests/feature_selection_test.cpp
+++ b/tests/feature_selection_test.cpp
@@ -69,8 +69,7 @@ go_bandit([]() {
     });
 
     f_idx = nullptr;
-    filesystem::remove_all("ceeaus-inv");
-    filesystem::remove_all("ceeaus-fwd");
+    filesystem::remove_all("ceeaus");
     for (const std::string& id :
          {"chi-square", "info-gain", "corr-coef", "odds-ratio"}) {
         for (const std::string& suffix : {"1", "2", "3", "selected"}) {
diff --git a/tests/forward_index_test.cpp b/tests/forward_index_test.cpp
index 8a5954e0a..de785e208 100644
--- a/tests/forward_index_test.cpp
+++ b/tests/forward_index_test.cpp
@@ -27,8 +27,7 @@ std::shared_ptr<cpptoml::table> create_libsvm_config() {
     config->insert("prefix", *orig_config->get_as<std::string>("prefix"));
     config->insert("corpus", "libsvm.toml");
     config->insert("dataset", "breast-cancer");
-    config->insert("forward-index", "bcancer-fwd");
-    config->insert("inverted-index", "bcancer-inv");
+    config->insert("index", "bcancer");
 
     auto anas = cpptoml::make_table_array();
     auto ana = cpptoml::make_table();
@@ -151,16 +150,14 @@ go_bandit([]() {
         auto file_cfg = tests::create_config("file");
 
         it("should create the index", [&]() {
-            filesystem::remove_all("ceeaus-inv");
-            filesystem::remove_all("ceeaus-fwd");
+            filesystem::remove_all("ceeaus");
             ceeaus_forward_test(*file_cfg);
         });
 
         it("should load the index", [&]() { ceeaus_forward_test(*file_cfg); });
 
         it("should uninvert if specified", [&]() {
-            filesystem::remove_all("ceeaus-inv");
-            filesystem::remove_all("ceeaus-fwd");
+            filesystem::remove_all("ceeaus");
             file_cfg->insert("uninvert", true);
             ceeaus_forward_test(*file_cfg);
         });
@@ -170,16 +167,14 @@ go_bandit([]() {
         auto line_cfg = tests::create_config("line");
 
         it("should create the index", [&]() {
-            filesystem::remove_all("ceeaus-inv");
-            filesystem::remove_all("ceeaus-fwd");
+            filesystem::remove_all("ceeaus");
             ceeaus_forward_test(*line_cfg);
         });
 
         it("should load the index", [&]() { ceeaus_forward_test(*line_cfg); });
 
         it("should uninvert if specified", [&]() {
-            filesystem::remove_all("ceeaus-inv");
-            filesystem::remove_all("ceeaus-fwd");
+            filesystem::remove_all("ceeaus");
             line_cfg->insert("uninvert", true);
             ceeaus_forward_test(*line_cfg);
         });
@@ -213,7 +208,7 @@ go_bandit([]() {
         auto svm_cfg = create_libsvm_config();
 
         it("should create the index", [&]() {
-            filesystem::remove_all("bcancer-fwd");
+            filesystem::remove_all("bcancer");
             bcancer_forward_test(*svm_cfg);
         });
 
@@ -231,12 +226,11 @@ go_bandit([]() {
 
     describe("[forward-index] with zlib", []() {
 
-        filesystem::remove_all("ceeaus-fwd");
+        filesystem::remove_all("ceeaus");
         auto gz_cfg = tests::create_config("gz");
 
         it("should create the index", [&]() {
-            filesystem::remove_all("ceeaus-inv");
-            filesystem::remove_all("ceeaus-fwd");
+            filesystem::remove_all("ceeaus");
             ceeaus_forward_test(*gz_cfg);
         });
 
@@ -244,7 +238,6 @@ go_bandit([]() {
 
     });
 
-    filesystem::remove_all("ceeaus-inv");
-    filesystem::remove_all("ceeaus-fwd");
-    filesystem::remove_all("bcancer-fwd");
+    filesystem::remove_all("ceeaus");
+    filesystem::remove_all("bcancer");
 });
diff --git a/tests/inverted_index_test.cpp b/tests/inverted_index_test.cpp
index d62db6fe2..88e3edc54 100644
--- a/tests/inverted_index_test.cpp
+++ b/tests/inverted_index_test.cpp
@@ -76,7 +76,7 @@ go_bandit([]() {
         auto file_cfg = tests::create_config("file");
 
         it("should create the index", [&]() {
-            filesystem::remove_all("ceeaus-inv");
+            filesystem::remove_all("ceeaus");
             auto idx = index::make_index<index::inverted_index>(*file_cfg);
             check_ceeaus_expected(*idx);
         });
@@ -87,7 +87,7 @@ go_bandit([]() {
             check_term_id(*idx);
         });
 
-        filesystem::remove_all("ceeaus-inv");
+        filesystem::remove_all("ceeaus");
         it("should be able to store full text metadata", [&]() {
             auto docs = corpus::make_corpus(*file_cfg);
             check_full_text(*docs, *file_cfg);
@@ -96,7 +96,7 @@ go_bandit([]() {
 
     describe("[inverted-index] from line config", []() {
 
-        filesystem::remove_all("ceeaus-inv");
+        filesystem::remove_all("ceeaus");
         auto line_cfg = tests::create_config("line");
 
         it("should create the index", [&]() {
@@ -113,7 +113,7 @@ go_bandit([]() {
             check_term_id(*idx); // twice to check splay_caching
         });
 
-        filesystem::remove_all("ceeaus-inv");
+        filesystem::remove_all("ceeaus");
         it("should be able to store full text metadata", [&]() {
             auto docs = corpus::make_corpus(*line_cfg);
             check_full_text(*docs, *line_cfg);
@@ -150,7 +150,7 @@ go_bandit([]() {
 
     describe("[inverted-index] with zlib", []() {
 
-        filesystem::remove_all("ceeaus-inv");
+        filesystem::remove_all("ceeaus");
         auto gz_cfg = tests::create_config("gz");
 
         it("should create the index", [&]() {
@@ -164,12 +164,12 @@ go_bandit([]() {
             check_term_id(*idx);
         });
 
-        filesystem::remove_all("ceeaus-inv");
+        filesystem::remove_all("ceeaus");
         it("should be able to store full text metadata", [&]() {
             auto docs = corpus::make_corpus(*gz_cfg);
             check_full_text(*docs, *gz_cfg);
         });
     });
 
-    filesystem::remove_all("ceeaus-inv");
+    filesystem::remove_all("ceeaus");
 });
diff --git a/tests/ir_eval_test.cpp b/tests/ir_eval_test.cpp
index 8844fc43d..3d2c55cef 100644
--- a/tests/ir_eval_test.cpp
+++ b/tests/ir_eval_test.cpp
@@ -40,7 +40,7 @@ go_bandit([]() {
     describe("[ir-eval] retrieval metrics", []() {
 
         it("should give results on [0, 1] for all measures", []() {
-            filesystem::remove_all("ceeaus-inv");
+            filesystem::remove_all("ceeaus");
             auto file_cfg = tests::create_config("file");
             auto idx = index::make_index<index::inverted_index>(*file_cfg);
             index::okapi_bm25 ranker;
@@ -156,6 +156,8 @@ go_bandit([]() {
             AssertThat(eval.map(),
                        Is().GreaterThanOrEqualTo(0).And().LessThanOrEqualTo(1));
             AssertThat(eval.gmap(), EqualsWithDelta(0.0, delta));
+
+            filesystem::remove_all("ceeaus");
         });
     });
 
diff --git a/tests/ranker_test.cpp b/tests/ranker_test.cpp
index 6463db988..1ac39511e 100644
--- a/tests/ranker_test.cpp
+++ b/tests/ranker_test.cpp
@@ -4,8 +4,8 @@
  */
 
 #include "bandit/bandit.h"
-#include "meta/corpus/document.h"
 #include "create_config.h"
+#include "meta/corpus/document.h"
 #include "meta/index/ranker/all.h"
 
 using namespace bandit;
@@ -15,6 +15,7 @@ namespace {
 
 template <class Ranker, class Index>
 void test_rank(Ranker& r, Index& idx, const std::string& encoding) {
+    // exhaustive search for each document
     for (size_t i = 0; i < idx.num_docs(); ++i) {
         auto d_id = idx.docs()[i];
         auto path = idx.doc_path(d_id);
@@ -33,6 +34,20 @@ void test_rank(Ranker& r, Index& idx, const std::string& encoding) {
                        EqualsWithDelta(ranking[1].score, 0.0001));
         }
     }
+
+    // sanity checks for simple query
+    corpus::document query;
+    query.content("character");
+
+    auto ranking = r.score(idx, query);
+    // ensure there is diversity in the top 10 documents
+    AssertThat(ranking[0].score, Is().GreaterThan(ranking.back().score));
+
+    // check for sorted-ness of ranking
+    for (uint64_t i = 1; i < ranking.size(); ++i) {
+        AssertThat(ranking[i - 1].score,
+                   Is().GreaterThanOrEqualTo(ranking[i].score));
+    }
 }
 }
 
@@ -41,7 +56,7 @@ go_bandit([]() {
     describe("[rankers]", []() {
 
         auto config = tests::create_config("file");
-        filesystem::remove_all("ceeaus-inv");
+        filesystem::remove_all("ceeaus");
         auto idx = index::make_index<index::inverted_index>(*config);
         std::string encoding = "utf-8";
         if (auto enc = config->get_as<std::string>("encoding"))
@@ -73,6 +88,6 @@ go_bandit([]() {
         });
 
         idx = nullptr;
-        filesystem::remove_all("ceeaus-inv");
+        filesystem::remove_all("ceeaus");
     });
 });
diff --git a/tests/regression_test.cpp b/tests/regression_test.cpp
index 4f7940603..26e8f01e2 100644
--- a/tests/regression_test.cpp
+++ b/tests/regression_test.cpp
@@ -53,10 +53,9 @@ go_bandit([]() {
 
     config->insert("dataset", "housing");
     config->insert("corpus", "libsvm.toml");
-    config->insert("forward-index", "housing-fwd");
-    config->insert("inverted-index", "housing-inv");
+    config->insert("index", "housing");
 
-    filesystem::remove_all("housing-fwd");
+    filesystem::remove_all("housing");
     auto f_idx = index::make_index<index::forward_index>(*config);
 
     regression::regression_dataset dataset{
@@ -101,5 +100,5 @@ go_bandit([]() {
     });
 
     f_idx = nullptr;
-    filesystem::remove_all("housing-fwd");
+    filesystem::remove_all("housing");
 });
diff --git a/tests/topics_test.cpp b/tests/topics_test.cpp
index a63309324..508f5be19 100644
--- a/tests/topics_test.cpp
+++ b/tests/topics_test.cpp
@@ -76,5 +76,5 @@ go_bandit([]() {
            [&]() { run_model<topics::parallel_lda_gibbs>(idx, prefix); });
     });
 
-    filesystem::remove_all("ceeaus-fwd");
+    filesystem::remove_all("ceeaus");
 });
diff --git a/travis/install_libcxx.sh b/travis/install_libcxx.sh
index 4edd3c619..779035b20 100755
--- a/travis/install_libcxx.sh
+++ b/travis/install_libcxx.sh
@@ -1,15 +1,21 @@
 #!/bin/bash
 set -v
 cwd=$(pwd)
-svn co --quiet http://llvm.org/svn/llvm-project/llvm/trunk llvm
+
+LLVM_TAG="${LLVM_TAG:-RELEASE_381}"
+
+svn co --quiet http://llvm.org/svn/llvm-project/llvm/tags/$LLVM_TAG/final llvm
+
 cd llvm/projects
-svn co --quiet http://llvm.org/svn/llvm-project/libcxx/trunk libcxx
-svn co --quiet http://llvm.org/svn/llvm-project/libcxxabi/trunk libcxxabi
+svn co --quiet http://llvm.org/svn/llvm-project/libcxx/tags/$LLVM_TAG/final libcxx
+svn co --quiet http://llvm.org/svn/llvm-project/libcxxabi/tags/$LLVM_TAG/final libcxxabi
 cd ../
+
 mkdir build
 cd build
 cmake -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=$HOME ../
 make cxx
 make install-libcxx install-libcxxabi
+
 cd $cwd
 set +v
diff --git a/travis/install_osx.sh b/travis/install_osx.sh
index 99dd5651e..72e22de67 100755
--- a/travis/install_osx.sh
+++ b/travis/install_osx.sh
@@ -11,9 +11,9 @@ fi
 
 if [ "$COMPILER" == "gcc" ]; then
     brew tap homebrew/versions
-    brew install homebrew/versions/gcc5
-    export CC=gcc-5
-    export CXX=g++-5
+    brew install homebrew/versions/gcc6
+    export CC=gcc-6
+    export CXX=g++-6
 fi
 
 if [ "$COMPILER" == "clang" ]; then