diff --git a/hphp/third_party/folly/folly/Bits.h b/hphp/third_party/folly/folly/Bits.h
index 0b45f84f3..2b5225243 100644
--- a/hphp/third_party/folly/folly/Bits.h
+++ b/hphp/third_party/folly/folly/Bits.h
@@ -57,10 +57,6 @@
 
 #include "folly/Portability.h"
 
-#ifndef _GNU_SOURCE
-#define _GNU_SOURCE 1
-#endif
-
 #ifndef __GNUC__
 #error GCC required
 #endif
diff --git a/hphp/third_party/folly/folly/FBString.h b/hphp/third_party/folly/folly/FBString.h
index a410a1861..cc34fe668 100644
--- a/hphp/third_party/folly/folly/FBString.h
+++ b/hphp/third_party/folly/folly/FBString.h
@@ -985,7 +985,7 @@ private:
   }
 
 public:
-  // 21.3.1 construct/copy/destroy
+  // C++11 21.4.2 construct/copy/destroy
   explicit basic_fbstring(const A& a = A()) {
   }
 
@@ -1047,6 +1047,11 @@ public:
       : store_(s, n, c, a) {
   }
 
+  // Construction from initialization list
+  basic_fbstring(std::initializer_list<value_type> il) {
+    assign(il.begin(), il.end());
+  }
+
   ~basic_fbstring() {
   }
 
@@ -1076,7 +1081,7 @@ public:
   basic_fbstring& operator=(basic_fbstring&& goner) {
     if (FBSTRING_UNLIKELY(&goner == this)) {
       // Compatibility with std::basic_string<>,
-      // 21.4.2 [string.cons] / 23 requires self-move-assignment support.
+      // C++11 21.4.2 [string.cons] / 23 requires self-move-assignment support.
       return *this;
     }
     // No need of this anymore
@@ -1121,11 +1126,17 @@ public:
     return *this;
   }
 
-  // 21.3.2 iterators:
+  basic_fbstring& operator=(std::initializer_list<value_type> il) {
+    return assign(il.begin(), il.end());
+  }
+
+  // C++11 21.4.3 iterators:
   iterator begin() { return store_.mutable_data(); }
 
   const_iterator begin() const { return store_.data(); }
 
+  const_iterator cbegin() const { return begin(); }
+
   iterator end() {
     return store_.mutable_data() + store_.size();
   }
@@ -1134,6 +1145,8 @@ public:
     return store_.data() + store_.size();
   }
 
+  const_iterator cend() const { return end(); }
+
   reverse_iterator rbegin() {
     return reverse_iterator(end());
   }
@@ -1142,6 +1155,8 @@ public:
     return const_reverse_iterator(end());
   }
 
+  const_reverse_iterator crbegin() const { return rbegin(); }
+
   reverse_iterator rend() {
     return reverse_iterator(begin());
   }
@@ -1150,6 +1165,8 @@ public:
     return const_reverse_iterator(begin());
   }
 
+  const_reverse_iterator crend() const { return rend(); }
+
   // Added by C++11
   // C++11 21.4.5, element access:
   const value_type& front() const { return *begin(); }
@@ -1169,7 +1186,7 @@ public:
     store_.shrink(1);
   }
 
-  // 21.3.3 capacity:
+  // C++11 21.4.4 capacity:
   size_type size() const { return store_.size(); }
 
   size_type length() const { return size(); }
@@ -1213,11 +1230,19 @@ public:
     store_.reserve(res_arg);
   }
 
+  void shrink_to_fit() {
+    // Shrink only if slack memory is sufficiently large
+    if (capacity() < size() * 3 / 2) {
+      return;
+    }
+    basic_fbstring(cbegin(), cend()).swap(*this);
+  }
+
   void clear() { resize(0); }
 
   bool empty() const { return size() == 0; }
 
-  // 21.3.4 element access:
+  // C++11 21.4.5 element access:
   const_reference operator[](size_type pos) const {
     return *(c_str() + pos);
   }
@@ -1240,7 +1265,7 @@ public:
     return (*this)[n];
   }
 
-  // 21.3.5 modifiers:
+  // C++11 21.4.6 modifiers:
   basic_fbstring& operator+=(const basic_fbstring& str) {
     return append(str);
   }
@@ -1254,6 +1279,11 @@ public:
     return *this;
   }
 
+  basic_fbstring& operator+=(std::initializer_list<value_type> il) {
+    append(il);
+    return *this;
+  }
+
   basic_fbstring& append(const basic_fbstring& str) {
 #ifndef NDEBUG
     auto desiredSize = size() + str.size();
@@ -1323,6 +1353,10 @@ public:
     return *this;
   }
 
+  basic_fbstring& append(std::initializer_list<value_type> il) {
+    return append(il.begin(), il.end());
+  }
+
   void push_back(const value_type c) {             // primitive
     store_.push_back(c);
   }
@@ -1332,6 +1366,10 @@ public:
     return assign(str.data(), str.size());
   }
 
+  basic_fbstring& assign(basic_fbstring&& str) {
+    return *this = std::move(str);
+  }
+
   basic_fbstring& assign(const basic_fbstring& str, const size_type pos,
                          size_type n) {
     const size_type sz = str.size();
@@ -1362,6 +1400,10 @@ public:
     return assign(s, traits_type::length(s));
   }
 
+  basic_fbstring& assign(std::initializer_list<value_type> il) {
+    return assign(il.begin(), il.end());
+  }
+
   template <class ItOrLength, class ItOrChar>
   basic_fbstring& assign(ItOrLength first_or_n, ItOrChar last_or_c) {
     return replace(begin(), end(), first_or_n, last_or_c);
@@ -1394,7 +1436,7 @@ public:
     return *this;
   }
 
-  iterator insert(const iterator p, const value_type c) {
+  iterator insert(const_iterator p, const value_type c) {
     const size_type pos = p - begin();
     insert(p, 1, c);
     return begin() + pos;
@@ -1403,10 +1445,11 @@ public:
 private:
   template <int i> class Selector {};
 
-  basic_fbstring& insertImplDiscr(iterator p,
-                                  size_type n, value_type c, Selector<1>) {
+  iterator insertImplDiscr(const_iterator p,
+                           size_type n, value_type c, Selector<1>) {
     Invariant checker(*this);
     (void) checker;
+    auto const pos = p - begin();
     assert(p >= begin() && p <= end());
     if (capacity() - size() < n) {
       const size_type sz = p - begin();
@@ -1414,33 +1457,33 @@ private:
       p = begin() + sz;
     }
     const iterator oldEnd = end();
-    if( n < size_type(oldEnd - p)) {
+    if (n < size_type(oldEnd - p)) {
       append(oldEnd - n, oldEnd);
       //std::copy(
       //    reverse_iterator(oldEnd - n),
       //    reverse_iterator(p),
       //    reverse_iterator(oldEnd));
-      fbstring_detail::pod_move(&*p, &*oldEnd - n, &*p + n);
-      std::fill(p, p + n, c);
+      fbstring_detail::pod_move(&*p, &*oldEnd - n,
+                                begin() + pos + n);
+      std::fill(begin() + pos, begin() + pos + n, c);
     } else {
       append(n - (end() - p), c);
-      append(p, oldEnd);
-      std::fill(p, oldEnd, c);
+      append(iterator(p), oldEnd);
+      std::fill(iterator(p), oldEnd, c);
     }
     store_.writeTerminator();
-    return *this;
+    return begin() + pos;
   }
 
   template<class InputIter>
-  basic_fbstring& insertImplDiscr(iterator i,
-                                  InputIter b, InputIter e, Selector<0>) {
-    insertImpl(i, b, e,
+  iterator insertImplDiscr(const_iterator i,
+                           InputIter b, InputIter e, Selector<0>) {
+    return insertImpl(i, b, e,
                typename std::iterator_traits<InputIter>::iterator_category());
-    return *this;
   }
 
   template <class FwdIterator>
-  void insertImpl(iterator i,
+  iterator insertImpl(const_iterator i,
                   FwdIterator s1, FwdIterator s2, std::forward_iterator_tag) {
     Invariant checker(*this);
     (void) checker;
@@ -1462,9 +1505,9 @@ private:
       const iterator tailBegin = end() - n2;
       store_.expand_noinit(n2);
       fbstring_detail::pod_copy(tailBegin, tailBegin + n2, end() - n2);
-      std::copy(reverse_iterator(tailBegin), reverse_iterator(i),
+      std::copy(const_reverse_iterator(tailBegin), const_reverse_iterator(i),
                 reverse_iterator(tailBegin + n2));
-      std::copy(s1, s2, i);
+      std::copy(s1, s2, begin() + pos);
     } else {
       FwdIterator t = s1;
       const size_type old_size = size();
@@ -1474,27 +1517,35 @@ private:
       std::copy(t, s2, begin() + old_size);
       fbstring_detail::pod_copy(data() + pos, data() + old_size,
                                  begin() + old_size + newElems);
-      std::copy(s1, t, i);
+      std::copy(s1, t, begin() + pos);
     }
     store_.writeTerminator();
+    return begin() + pos;
   }
 
   template <class InputIterator>
-  void insertImpl(iterator i,
-                  InputIterator b, InputIterator e, std::input_iterator_tag) {
+  iterator insertImpl(const_iterator i,
+                      InputIterator b, InputIterator e,
+                      std::input_iterator_tag) {
+    const auto pos = i - begin();
     basic_fbstring temp(begin(), i);
     for (; b != e; ++b) {
       temp.push_back(*b);
     }
-    temp.append(i, end());
+    temp.append(i, cend());
     swap(temp);
+    return begin() + pos;
   }
 
 public:
   template <class ItOrLength, class ItOrChar>
-  void insert(iterator p, ItOrLength first_or_n, ItOrChar last_or_c) {
+  iterator insert(const_iterator p, ItOrLength first_or_n, ItOrChar last_or_c) {
     Selector<std::numeric_limits<ItOrLength>::is_specialized> sel;
-    insertImplDiscr(p, first_or_n, last_or_c, sel);
+    return insertImplDiscr(p, first_or_n, last_or_c, sel);
+  }
+
+  iterator insert(const_iterator p, std::initializer_list<value_type> il) {
+    return insert(p, il.begin(), il.end());
   }
 
   basic_fbstring& erase(size_type pos = 0, size_type n = npos) {
@@ -1690,7 +1741,6 @@ public:
     store_.swap(rhs.store_);
   }
 
-  // 21.3.6 string operations:
   const value_type* c_str() const {
     return store_.c_str();
   }
@@ -2165,7 +2215,7 @@ bool operator>=(const typename basic_fbstring<E, T, A, S>::value_type* lhs,
  return !(lhs < rhs);
 }
 
-// subclause 21.3.7.8:
+// C++11 21.4.8.8
 template <typename E, class T, class A, class S>
 void swap(basic_fbstring<E, T, A, S>& lhs, basic_fbstring<E, T, A, S>& rhs) {
   lhs.swap(rhs);
diff --git a/hphp/third_party/folly/folly/Hash.h b/hphp/third_party/folly/folly/Hash.h
index 132ad846e..cbd07b56b 100644
--- a/hphp/third_party/folly/folly/Hash.h
+++ b/hphp/third_party/folly/folly/Hash.h
@@ -21,6 +21,7 @@
 #include <stdint.h>
 #include <string>
 #include <utility>
+#include <tuple>
 
 #include "folly/SpookyHashV1.h"
 #include "folly/SpookyHashV2.h"
@@ -348,6 +349,26 @@ template<> struct hasher<uint64_t> {
   }
 };
 
+// recursion
+template <size_t index, typename... Ts>
+struct TupleHasher {
+  size_t operator()(std::tuple<Ts...> const& key) const {
+    return hash::hash_combine(
+      TupleHasher<index - 1, Ts...>()(key),
+      std::get<index>(key));
+  }
+};
+
+// base
+template <typename... Ts>
+struct TupleHasher<0, Ts...> {
+  size_t operator()(std::tuple<Ts...> const& key) const {
+    // we could do std::hash here directly, but hash_combine hides all the
+    // ugly templating implicitly
+    return hash::hash_combine(std::get<0>(key));
+  }
+};
+
 } // namespace folly
 
 // Custom hash functions.
@@ -361,6 +382,18 @@ namespace std {
       return folly::hash::hash_combine(x.first, x.second);
     }
   };
+
+  // Hash function for tuples. Requires default hash functions for all types.
+  template <typename... Ts>
+  struct hash<std::tuple<Ts...>> {
+    size_t operator()(std::tuple<Ts...> const& key) const {
+      folly::TupleHasher<
+        std::tuple_size<std::tuple<Ts...>>::value - 1, // start index
+        Ts...> hasher;
+
+      return hasher(key);
+    }
+  };
 } // namespace std
 
 #endif
diff --git a/hphp/third_party/folly/folly/String.h b/hphp/third_party/folly/folly/String.h
index 93a4c6583..d706a0321 100644
--- a/hphp/third_party/folly/folly/String.h
+++ b/hphp/third_party/folly/folly/String.h
@@ -443,6 +443,13 @@ void join(const Delim& delimiter,
   join(delimiter, container.begin(), container.end(), output);
 }
 
+template <class Delim, class Value, class String>
+void join(const Delim& delimiter,
+          const std::initializer_list<Value>& values,
+          String& output) {
+  join(delimiter, values.begin(), values.end(), output);
+}
+
 template <class Delim, class Container>
 std::string join(const Delim& delimiter,
                  const Container& container) {
@@ -451,6 +458,14 @@ std::string join(const Delim& delimiter,
   return output;
 }
 
+template <class Delim, class Value>
+std::string join(const Delim& delimiter,
+                 const std::initializer_list<Value>& values) {
+  std::string output;
+  join(delimiter, values.begin(), values.end(), output);
+  return output;
+}
+
 } // namespace folly
 
 // Hash functions for string and fbstring usable with e.g. hash_map
diff --git a/hphp/third_party/folly/folly/experimental/Gen-inl.h b/hphp/third_party/folly/folly/experimental/Gen-inl.h
index 8b0c4dc74..f553cc869 100644
--- a/hphp/third_party/folly/folly/experimental/Gen-inl.h
+++ b/hphp/third_party/folly/folly/experimental/Gen-inl.h
@@ -1675,11 +1675,11 @@ class RangeConcat : public Operator<RangeConcat> {
  public:
   RangeConcat() { }
 
-  template<class Source,
-           class Range,
+  template<class Range,
+           class Source,
            class InnerValue = typename ValueTypeOfRange<Range>::RefType>
   class Generator
-    : public GenImpl<InnerValue, Generator<Source, Range, InnerValue>> {
+    : public GenImpl<InnerValue, Generator<Range, Source, InnerValue>> {
     Source source_;
    public:
     explicit Generator(Source source)
@@ -1709,19 +1709,91 @@ class RangeConcat : public Operator<RangeConcat> {
 
   template<class Value,
            class Source,
-           class Gen = Generator<Source, Value>>
+           class Gen = Generator<Value, Source>>
   Gen compose(GenImpl<Value, Source>&& source) const {
     return Gen(std::move(source.self()));
   }
 
   template<class Value,
            class Source,
-           class Gen = Generator<Source, Value>>
+           class Gen = Generator<Value, Source>>
   Gen compose(const GenImpl<Value, Source>& source) const {
     return Gen(source.self());
   }
 };
 
+
+/**
+ * GuardImpl - For handling exceptions from downstream computation. Requires the
+ * type of exception to catch, and handler function to invoke in the event of
+ * the exception. Note that the handler may:
+ *   1) return true to continue processing the sequence
+ *   2) return false to end the sequence immediately
+ *   3) throw, to pass the exception to the next catch
+ * The handler must match the signature 'bool(Exception&, Value)'.
+ *
+ * This type is used through the `guard` helper, like so:
+ *
+ *  auto indexes
+ *    = byLine(STDIN_FILENO)
+ *    | guard<std::runtime_error>([](std::runtime_error& e,
+ *                                   StringPiece sp) {
+ *        LOG(ERROR) << sp << ": " << e.str();
+ *        return true; // continue processing subsequent lines
+ *      })
+ *    | eachTo<int>()
+ *    | as<vector>();
+ *
+ *  TODO(tjackson): Rename this back to Guard.
+ **/
+template<class Exception,
+         class ErrorHandler>
+class GuardImpl : public Operator<GuardImpl<Exception, ErrorHandler>> {
+  ErrorHandler handler_;
+ public:
+  GuardImpl(ErrorHandler handler)
+    : handler_(std::move(handler)) {}
+
+  template<class Value,
+           class Source>
+  class Generator : public GenImpl<Value, Generator<Value, Source>> {
+    Source source_;
+    ErrorHandler handler_;
+  public:
+    explicit Generator(Source source,
+                       ErrorHandler handler)
+      : source_(std::move(source)),
+        handler_(std::move(handler)) {}
+
+    template<class Handler>
+    bool apply(Handler&& handler) const {
+      return source_.apply([&](Value value) -> bool {
+        try {
+          handler(std::forward<Value>(value));
+          return true;
+        } catch (Exception& e) {
+          return handler_(e, std::forward<Value>(value));
+        }
+      });
+    }
+
+    static constexpr bool infinite = Source::infinite;
+  };
+
+  template<class Value,
+           class Source,
+           class Gen = Generator<Value, Source>>
+  Gen compose(GenImpl<Value, Source>&& source) const {
+    return Gen(std::move(source.self()), handler_);
+  }
+
+  template<class Value,
+           class Source,
+           class Gen = Generator<Value, Source>>
+  Gen compose(const GenImpl<Value, Source>& source) const {
+    return Gen(source.self(), handler_);
+  }
+};
 } //::detail
 
 /**
diff --git a/hphp/third_party/folly/folly/experimental/Gen.h b/hphp/third_party/folly/folly/experimental/Gen.h
index 47fab1976..342968b02 100644
--- a/hphp/third_party/folly/folly/experimental/Gen.h
+++ b/hphp/third_party/folly/folly/experimental/Gen.h
@@ -343,6 +343,10 @@ struct GeneratorBuilder;
 template<class Needle>
 class Contains;
 
+template<class Exception,
+         class ErrorHandler>
+class GuardImpl;
+
 }
 
 /**
@@ -622,6 +626,16 @@ Contains contains(Needle&& needle) {
   return Contains(std::forward<Needle>(needle));
 }
 
+template<class Exception,
+         class ErrorHandler,
+         class GuardImpl =
+           detail::GuardImpl<
+             Exception,
+             typename std::decay<ErrorHandler>::type>>
+GuardImpl guard(ErrorHandler&& handler) {
+  return GuardImpl(std::forward<ErrorHandler>(handler));
+}
+
 }} // folly::gen
 
 #include "folly/experimental/Gen-inl.h"
diff --git a/hphp/third_party/folly/folly/io/RecordIO.cpp b/hphp/third_party/folly/folly/io/RecordIO.cpp
index 566ce3656..a40750573 100644
--- a/hphp/third_party/folly/folly/io/RecordIO.cpp
+++ b/hphp/third_party/folly/folly/io/RecordIO.cpp
@@ -201,7 +201,6 @@ RecordInfo findRecord(ByteRange searchRange,
   static const uint32_t magic = Header::kMagic;
   static const ByteRange magicRange(reinterpret_cast<const uint8_t*>(&magic),
                                     sizeof(magic));
-  static constexpr size_t headerTail = sizeof(Header) - sizeof(magic);
 
   DCHECK_GE(searchRange.begin(), wholeRange.begin());
   DCHECK_LE(searchRange.end(), wholeRange.end());