diff --git a/include/llvm/ADT/APFloat.h b/include/llvm/ADT/APFloat.h
index acfefe9d89a..50f1463d7ea 100644
--- a/include/llvm/ADT/APFloat.h
+++ b/include/llvm/ADT/APFloat.h
@@ -236,19 +236,19 @@ public:
       APInt fill(64, type);
       return getQNaN(Sem, Negative, &fill);
     } else {
-      return getQNaN(Sem, Negative, 0);
+      return getQNaN(Sem, Negative, nullptr);
     }
   }
 
   /// Factory for QNaN values.
   static APFloat getQNaN(const fltSemantics &Sem, bool Negative = false,
-                         const APInt *payload = 0) {
+                         const APInt *payload = nullptr) {
     return makeNaN(Sem, false, Negative, payload);
   }
 
   /// Factory for SNaN values.
   static APFloat getSNaN(const fltSemantics &Sem, bool Negative = false,
-                         const APInt *payload = 0) {
+                         const APInt *payload = nullptr) {
     return makeNaN(Sem, true, Negative, payload);
   }
 
@@ -500,7 +500,8 @@ private:
 
   void makeLargest(bool Neg = false);
   void makeSmallest(bool Neg = false);
-  void makeNaN(bool SNaN = false, bool Neg = false, const APInt *fill = 0);
+  void makeNaN(bool SNaN = false, bool Neg = false,
+               const APInt *fill = nullptr);
   static APFloat makeNaN(const fltSemantics &Sem, bool SNaN, bool Negative,
                          const APInt *fill);
   void makeInf(bool Neg = false);
diff --git a/include/llvm/ADT/ArrayRef.h b/include/llvm/ADT/ArrayRef.h
index fcf280d4451..87b9bb95abf 100644
--- a/include/llvm/ADT/ArrayRef.h
+++ b/include/llvm/ADT/ArrayRef.h
@@ -52,7 +52,7 @@ namespace llvm {
     /*implicit*/ ArrayRef() : Data(0), Length(0) {}
 
     /// Construct an empty ArrayRef from None.
-    /*implicit*/ ArrayRef(NoneType) : Data(0), Length(0) {}
+    /*implicit*/ ArrayRef(NoneType) : Data(nullptr), Length(0) {}
 
     /// Construct an ArrayRef from a single element.
     /*implicit*/ ArrayRef(const T &OneElt)
diff --git a/include/llvm/ADT/DenseMap.h b/include/llvm/ADT/DenseMap.h
index 037989f49db..37385da23b1 100644
--- a/include/llvm/ADT/DenseMap.h
+++ b/include/llvm/ADT/DenseMap.h
@@ -461,12 +461,12 @@ private:
     const unsigned NumBuckets = getNumBuckets();
 
     if (NumBuckets == 0) {
-      FoundBucket = 0;
+      FoundBucket = nullptr;
       return false;
     }
 
     // FoundTombstone - Keep track of whether we find a tombstone while probing.
-    const BucketT *FoundTombstone = 0;
+    const BucketT *FoundTombstone = nullptr;
     const KeyT EmptyKey = getEmptyKey();
     const KeyT TombstoneKey = getTombstoneKey();
     assert(!KeyInfoT::isEqual(Val, EmptyKey) &&
@@ -665,7 +665,7 @@ private:
   bool allocateBuckets(unsigned Num) {
     NumBuckets = Num;
     if (NumBuckets == 0) {
-      Buckets = 0;
+      Buckets = nullptr;
       return false;
     }
 
diff --git a/include/llvm/ADT/FoldingSet.h b/include/llvm/ADT/FoldingSet.h
index 188010d8ba4..9b7ee8520d7 100644
--- a/include/llvm/ADT/FoldingSet.h
+++ b/include/llvm/ADT/FoldingSet.h
@@ -137,7 +137,7 @@ public:
 
   public:
 
-    Node() : NextInFoldingSetBucket(0) {}
+    Node() : NextInFoldingSetBucket(nullptr) {}
 
     // Accessors
     void *getNextInBucket() const { return NextInFoldingSetBucket; }
@@ -269,7 +269,7 @@ class FoldingSetNodeIDRef {
   const unsigned *Data;
   size_t Size;
 public:
-  FoldingSetNodeIDRef() : Data(0), Size(0) {}
+  FoldingSetNodeIDRef() : Data(nullptr), Size(0) {}
   FoldingSetNodeIDRef(const unsigned *D, size_t S) : Data(D), Size(S) {}
 
   /// ComputeHash - Compute a strong hash value for this FoldingSetNodeIDRef,
diff --git a/include/llvm/ADT/IntrusiveRefCntPtr.h b/include/llvm/ADT/IntrusiveRefCntPtr.h
index 729e37f06a1..449f445e71b 100644
--- a/include/llvm/ADT/IntrusiveRefCntPtr.h
+++ b/include/llvm/ADT/IntrusiveRefCntPtr.h
@@ -139,7 +139,7 @@ public:
   public:
     typedef T element_type;
 
-    explicit IntrusiveRefCntPtr() : Obj(0) {}
+    explicit IntrusiveRefCntPtr() : Obj(nullptr) {}
 
     IntrusiveRefCntPtr(T* obj) : Obj(obj) {
       retain();
@@ -150,7 +150,7 @@ public:
     }
 
     IntrusiveRefCntPtr(IntrusiveRefCntPtr&& S) : Obj(S.Obj) {
-      S.Obj = 0;
+      S.Obj = nullptr;
     }
 
     template <class X>
@@ -179,7 +179,7 @@ public:
 
     typedef T* (IntrusiveRefCntPtr::*unspecified_bool_type) () const;
     operator unspecified_bool_type() const {
-      return Obj == 0 ? 0 : &IntrusiveRefCntPtr::getPtr;
+      return Obj == nullptr ? nullptr : &IntrusiveRefCntPtr::getPtr;
     }
 
     void swap(IntrusiveRefCntPtr& other) {
@@ -190,7 +190,7 @@ public:
 
     void reset() {
       release();
-      Obj = 0;
+      Obj = nullptr;
     }
 
     void resetWithoutRelease() {
diff --git a/include/llvm/ADT/StringMap.h b/include/llvm/ADT/StringMap.h
index 4e74cf6529e..d4daf531782 100644
--- a/include/llvm/ADT/StringMap.h
+++ b/include/llvm/ADT/StringMap.h
@@ -50,7 +50,7 @@ protected:
 protected:
   explicit StringMapImpl(unsigned itemSize) : ItemSize(itemSize) {
     // Initialize the map with zero buckets to allocation.
-    TheTable = 0;
+    TheTable = nullptr;
     NumBuckets = 0;
     NumItems = 0;
     NumTombstones = 0;
@@ -330,7 +330,7 @@ public:
       if (Bucket && Bucket != getTombstoneVal()) {
         static_cast<MapEntryTy*>(Bucket)->Destroy(Allocator);
       }
-      Bucket = 0;
+      Bucket = nullptr;
     }
 
     NumItems = 0;
@@ -410,7 +410,7 @@ protected:
 public:
   typedef StringMapEntry<ValueTy> value_type;
 
-  StringMapConstIterator() : Ptr(0) { }
+  StringMapConstIterator() : Ptr(nullptr) { }
 
   explicit StringMapConstIterator(StringMapEntryBase **Bucket,
                                   bool NoAdvance = false)
@@ -443,7 +443,7 @@ public:
 
 private:
   void AdvancePastEmptyBuckets() {
-    while (*Ptr == 0 || *Ptr == StringMapImpl::getTombstoneVal())
+    while (*Ptr == nullptr || *Ptr == StringMapImpl::getTombstoneVal())
       ++Ptr;
   }
 };
diff --git a/include/llvm/ADT/StringRef.h b/include/llvm/ADT/StringRef.h
index 0514d7b1964..d306b399faf 100644
--- a/include/llvm/ADT/StringRef.h
+++ b/include/llvm/ADT/StringRef.h
@@ -70,7 +70,7 @@ namespace llvm {
     /// @{
 
     /// Construct an empty string ref.
-    /*implicit*/ StringRef() : Data(0), Length(0) {}
+    /*implicit*/ StringRef() : Data(nullptr), Length(0) {}
 
     /// Construct a string ref from a cstring.
     /*implicit*/ StringRef(const char *Str)
@@ -186,7 +186,7 @@ namespace llvm {
 
     /// str - Get the contents as an std::string.
     std::string str() const {
-      if (Data == 0) return std::string();
+      if (Data == nullptr) return std::string();
       return std::string(Data, Length);
     }
 
diff --git a/include/llvm/ADT/StringSwitch.h b/include/llvm/ADT/StringSwitch.h
index 7fd6e279603..0393a0c373e 100644
--- a/include/llvm/ADT/StringSwitch.h
+++ b/include/llvm/ADT/StringSwitch.h
@@ -49,7 +49,7 @@ class StringSwitch {
 
 public:
   explicit StringSwitch(StringRef S)
-  : Str(S), Result(0) { }
+  : Str(S), Result(nullptr) { }
 
   template<unsigned N>
   StringSwitch& Case(const char (&S)[N], const T& Value) {
diff --git a/include/llvm/ADT/Twine.h b/include/llvm/ADT/Twine.h
index e16c6b49138..a54fd743ad6 100644
--- a/include/llvm/ADT/Twine.h
+++ b/include/llvm/ADT/Twine.h
@@ -374,7 +374,7 @@ namespace llvm {
     static Twine utohexstr(const uint64_t &Val) {
       Child LHS, RHS;
       LHS.uHex = &Val;
-      RHS.twine = 0;
+      RHS.twine = nullptr;
       return Twine(LHS, UHexKind, RHS, EmptyKind);
     }
 
diff --git a/include/llvm/ADT/ilist.h b/include/llvm/ADT/ilist.h
index 6aeaa91f1b1..3c076d4399d 100644
--- a/include/llvm/ADT/ilist.h
+++ b/include/llvm/ADT/ilist.h
@@ -175,7 +175,7 @@ public:
 
   ilist_iterator(pointer NP) : NodePtr(NP) {}
   ilist_iterator(reference NR) : NodePtr(&NR) {}
-  ilist_iterator() : NodePtr(0) {}
+  ilist_iterator() : NodePtr(nullptr) {}
 
   // This is templated so that we can allow constructing a const iterator from
   // a nonconst iterator...
@@ -383,7 +383,7 @@ public:
   // Miscellaneous inspection routines.
   size_type max_size() const { return size_type(-1); }
   bool LLVM_ATTRIBUTE_UNUSED_RESULT empty() const {
-    return Head == 0 || Head == getTail();
+    return Head == nullptr || Head == getTail();
   }
 
   // Front and back accessor functions...
@@ -451,8 +451,8 @@ public:
     // an ilist (and potentially deleted) with iterators still pointing at it.
     // When those iterators are incremented or decremented, they will assert on
     // the null next/prev pointer instead of "usually working".
-    this->setNext(Node, 0);
-    this->setPrev(Node, 0);
+    this->setNext(Node, nullptr);
+    this->setPrev(Node, nullptr);
     return Node;
   }
 
diff --git a/include/llvm/ADT/ilist_node.h b/include/llvm/ADT/ilist_node.h
index 03612440e7a..269fa519580 100644
--- a/include/llvm/ADT/ilist_node.h
+++ b/include/llvm/ADT/ilist_node.h
@@ -30,7 +30,7 @@ protected:
   NodeTy *getPrev() { return Prev; }
   const NodeTy *getPrev() const { return Prev; }
   void setPrev(NodeTy *P) { Prev = P; }
-  ilist_half_node() : Prev(0) {}
+  ilist_half_node() : Prev(nullptr) {}
 };
 
 template<typename NodeTy>
@@ -48,7 +48,7 @@ class ilist_node : private ilist_half_node<NodeTy> {
   const NodeTy *getNext() const { return Next; }
   void setNext(NodeTy *N) { Next = N; }
 protected:
-  ilist_node() : Next(0) {}
+  ilist_node() : Next(nullptr) {}
 
 public:
   /// @name Adjacent Node Accessors
diff --git a/include/llvm/Support/Allocator.h b/include/llvm/Support/Allocator.h
index 06413225a98..d9cb8ba428b 100644
--- a/include/llvm/Support/Allocator.h
+++ b/include/llvm/Support/Allocator.h
@@ -106,7 +106,7 @@ protected:
   /// Used so that we can compute how much space was wasted.
   size_t BytesAllocated;
 
-  BumpPtrAllocatorBase() : CurSlab(0), BytesAllocated(0) {}
+  BumpPtrAllocatorBase() : CurSlab(nullptr), BytesAllocated(0) {}
 };
 
 /// \brief Allocate memory in an ever growing pool, as if by bump-pointer.
@@ -142,7 +142,7 @@ public:
     if (!CurSlab)
       return;
     DeallocateSlabs(CurSlab->NextPtr);
-    CurSlab->NextPtr = 0;
+    CurSlab->NextPtr = nullptr;
     CurPtr = (char *)(CurSlab + 1);
     End = ((char *)CurSlab) + CurSlab->Size;
     BytesAllocated = 0;
diff --git a/include/llvm/Support/Casting.h b/include/llvm/Support/Casting.h
index 689f5908343..5f3e94d6938 100644
--- a/include/llvm/Support/Casting.h
+++ b/include/llvm/Support/Casting.h
@@ -275,7 +275,7 @@ dyn_cast(Y &Val) {
 template <class X, class Y>
 LLVM_ATTRIBUTE_UNUSED_RESULT inline typename cast_retty<X, Y *>::ret_type
 dyn_cast(Y *Val) {
-  return isa<X>(Val) ? cast<X>(Val) : 0;
+  return isa<X>(Val) ? cast<X>(Val) : nullptr;
 }
 
 // dyn_cast_or_null<X> - Functionally identical to dyn_cast, except that a null
@@ -284,7 +284,7 @@ dyn_cast(Y *Val) {
 template <class X, class Y>
 LLVM_ATTRIBUTE_UNUSED_RESULT inline typename cast_retty<X, Y *>::ret_type
 dyn_cast_or_null(Y *Val) {
-  return (Val && isa<X>(Val)) ? cast<X>(Val) : 0;
+  return (Val && isa<X>(Val)) ? cast<X>(Val) : nullptr;
 }
 
 } // End llvm namespace
diff --git a/include/llvm/Support/CommandLine.h b/include/llvm/Support/CommandLine.h
index e49a97ea541..006680587b6 100644
--- a/include/llvm/Support/CommandLine.h
+++ b/include/llvm/Support/CommandLine.h
@@ -41,14 +41,14 @@ namespace cl {
 // ParseCommandLineOptions - Command line option processing entry point.
 //
 void ParseCommandLineOptions(int argc, const char * const *argv,
-                             const char *Overview = 0);
+                             const char *Overview = nullptr);
 
 //===----------------------------------------------------------------------===//
 // ParseEnvironmentOptions - Environment variable option processing alternate
 //                           entry point.
 //
 void ParseEnvironmentOptions(const char *progName, const char *envvar,
-                             const char *Overview = 0);
+                             const char *Overview = nullptr);
 
 ///===---------------------------------------------------------------------===//
 /// SetVersionPrinter - Override the default (LLVM specific) version printer
@@ -146,7 +146,7 @@ private:
   const char *const Description;
   void registerCategory();
 public:
-  OptionCategory(const char *const Name, const char *const Description = 0)
+  OptionCategory(const char *const Name, const char *const Description = nullptr)
       : Name(Name), Description(Description) { registerCategory(); }
   const char *getName() const { return Name; }
   const char *getDescription() const { return Description; }
@@ -238,7 +238,7 @@ protected:
                   enum OptionHidden Hidden)
     : NumOccurrences(0), Occurrences(OccurrencesFlag), Value(0),
       HiddenFlag(Hidden), Formatting(NormalFormatting), Misc(0),
-      Position(0), AdditionalVals(0), NextRegistered(0),
+      Position(0), AdditionalVals(0), NextRegistered(nullptr),
       ArgStr(""), HelpStr(""), ValueStr(""), Category(&GeneralCategory) {
   }
 
@@ -763,7 +763,7 @@ public:
   }
 
   // getValueName - Do not print =<value> at all.
-  const char *getValueName() const override { return 0; }
+  const char *getValueName() const override { return nullptr; }
 
   void printOptionDiff(const Option &O, bool V, OptVal Default,
                        size_t GlobalWidth) const;
@@ -787,7 +787,7 @@ public:
   }
 
   // getValueName - Do not print =<value> at all.
-  const char *getValueName() const override { return 0; }
+  const char *getValueName() const override { return nullptr; }
 
   void printOptionDiff(const Option &O, boolOrDefault V, OptVal Default,
                        size_t GlobalWidth) const;
@@ -1068,7 +1068,7 @@ class opt_storage {
            "or cl::init specified before cl::location()!!");
   }
 public:
-  opt_storage() : Location(0) {}
+  opt_storage() : Location(nullptr) {}
 
   bool setLocation(Option &O, DataType &L) {
     if (Location)
@@ -1469,7 +1469,7 @@ class bits_storage {
   }
 
 public:
-  bits_storage() : Location(0) {}
+  bits_storage() : Location(nullptr) {}
 
   bool setLocation(Option &O, unsigned &L) {
     if (Location)
@@ -1664,7 +1664,7 @@ class alias : public Option {
   void done() {
     if (!hasArgStr())
       error("cl::alias must have argument name specified!");
-    if (AliasFor == 0)
+    if (AliasFor == nullptr)
       error("cl::alias must have an cl::aliasopt(option) specified!");
       addArgument();
   }
@@ -1677,27 +1677,28 @@ public:
 
   // One option...
   template<class M0t>
-  explicit alias(const M0t &M0) : Option(Optional, Hidden), AliasFor(0) {
+  explicit alias(const M0t &M0) : Option(Optional, Hidden), AliasFor(nullptr) {
     apply(M0, this);
     done();
   }
   // Two options...
   template<class M0t, class M1t>
-  alias(const M0t &M0, const M1t &M1) : Option(Optional, Hidden), AliasFor(0) {
+  alias(const M0t &M0, const M1t &M1)
+    : Option(Optional, Hidden), AliasFor(nullptr) {
     apply(M0, this); apply(M1, this);
     done();
   }
   // Three options...
   template<class M0t, class M1t, class M2t>
   alias(const M0t &M0, const M1t &M1, const M2t &M2)
-    : Option(Optional, Hidden), AliasFor(0) {
+    : Option(Optional, Hidden), AliasFor(nullptr) {
     apply(M0, this); apply(M1, this); apply(M2, this);
     done();
   }
   // Four options...
   template<class M0t, class M1t, class M2t, class M3t>
   alias(const M0t &M0, const M1t &M1, const M2t &M2, const M3t &M3)
-    : Option(Optional, Hidden), AliasFor(0) {
+    : Option(Optional, Hidden), AliasFor(nullptr) {
     apply(M0, this); apply(M1, this); apply(M2, this); apply(M3, this);
     done();
   }
diff --git a/include/llvm/Support/CrashRecoveryContext.h b/include/llvm/Support/CrashRecoveryContext.h
index 4500efe7b8b..6b9e0439790 100644
--- a/include/llvm/Support/CrashRecoveryContext.h
+++ b/include/llvm/Support/CrashRecoveryContext.h
@@ -58,7 +58,7 @@ class CrashRecoveryContext {
   };
 
 public:
-  CrashRecoveryContext() : Impl(0), head(0) {}
+  CrashRecoveryContext() : Impl(nullptr), head(nullptr) {}
   ~CrashRecoveryContext();
   
   void registerCleanup(CrashRecoveryContextCleanup *cleanup);
diff --git a/include/llvm/Support/DynamicLibrary.h b/include/llvm/Support/DynamicLibrary.h
index 1e2d16ccbc8..de47be62a79 100644
--- a/include/llvm/Support/DynamicLibrary.h
+++ b/include/llvm/Support/DynamicLibrary.h
@@ -65,7 +65,7 @@ namespace sys {
     /// It is safe to call this function multiple times for the same library.
     /// @brief Open a dynamic library permanently.
     static DynamicLibrary getPermanentLibrary(const char *filename,
-                                              std::string *errMsg = 0);
+                                              std::string *errMsg = nullptr);
 
     /// This function permanently loads the dynamic library at the given path.
     /// Use this instead of getPermanentLibrary() when you won't need to get
@@ -73,7 +73,7 @@ namespace sys {
     ///
     /// It is safe to call this function multiple times for the same library.
     static bool LoadLibraryPermanently(const char *Filename,
-                                       std::string *ErrMsg = 0) {
+                                       std::string *ErrMsg = nullptr) {
       return !getPermanentLibrary(Filename, ErrMsg).isValid();
     }
 
diff --git a/include/llvm/Support/ErrorHandling.h b/include/llvm/Support/ErrorHandling.h
index b948d97bff9..ac3a4d86469 100644
--- a/include/llvm/Support/ErrorHandling.h
+++ b/include/llvm/Support/ErrorHandling.h
@@ -47,7 +47,7 @@ namespace llvm {
   /// \param user_data - An argument which will be passed to the install error
   /// handler.
   void install_fatal_error_handler(fatal_error_handler_t handler,
-                                   void *user_data = 0);
+                                   void *user_data = nullptr);
 
   /// Restores default error handling behaviour.
   /// This must not be called between llvm_start_multithreaded() and
@@ -59,7 +59,7 @@ namespace llvm {
   /// remove_fatal_error_handler in its destructor.
   struct ScopedFatalErrorHandler {
     explicit ScopedFatalErrorHandler(fatal_error_handler_t handler,
-                                     void *user_data = 0) {
+                                     void *user_data = nullptr) {
       install_fatal_error_handler(handler, user_data);
     }
 
@@ -86,9 +86,9 @@ namespace llvm {
   /// This function calls abort(), and prints the optional message to stderr.
   /// Use the llvm_unreachable macro (that adds location info), instead of
   /// calling this function directly.
-  LLVM_ATTRIBUTE_NORETURN void llvm_unreachable_internal(const char *msg=0,
-                                                         const char *file=0,
-                                                         unsigned line=0);
+  LLVM_ATTRIBUTE_NORETURN void
+  llvm_unreachable_internal(const char *msg=nullptr, const char *file=nullptr,
+                            unsigned line=0);
 }
 
 /// Marks that the current location is not supposed to be reachable.
diff --git a/include/llvm/Support/FileSystem.h b/include/llvm/Support/FileSystem.h
index b511a8e203c..52182a8e77b 100644
--- a/include/llvm/Support/FileSystem.h
+++ b/include/llvm/Support/FileSystem.h
@@ -814,7 +814,7 @@ public:
   }
 
   /// Construct end iterator.
-  directory_iterator() : State(0) {}
+  directory_iterator() : State(nullptr) {}
 
   // No operator++ because we need error_code.
   directory_iterator &increment(error_code &ec) {
@@ -828,9 +828,9 @@ public:
   bool operator==(const directory_iterator &RHS) const {
     if (State == RHS.State)
       return true;
-    if (RHS.State == 0)
+    if (RHS.State == nullptr)
       return State->CurrentEntry == directory_entry();
-    if (State == 0)
+    if (State == nullptr)
       return RHS.State->CurrentEntry == directory_entry();
     return State->CurrentEntry == RHS.State->CurrentEntry;
   }
diff --git a/include/llvm/Support/FileUtilities.h b/include/llvm/Support/FileUtilities.h
index 873b8df30e0..3f2f176eb46 100644
--- a/include/llvm/Support/FileUtilities.h
+++ b/include/llvm/Support/FileUtilities.h
@@ -30,7 +30,7 @@ namespace llvm {
   int DiffFilesWithTolerance(StringRef FileA,
                              StringRef FileB,
                              double AbsTol, double RelTol,
-                             std::string *Error = 0);
+                             std::string *Error = nullptr);
 
 
   /// FileRemover - This class is a simple object meant to be stack allocated.
diff --git a/include/llvm/Support/FormattedStream.h b/include/llvm/Support/FormattedStream.h
index 78c4809e120..8137daaff1f 100644
--- a/include/llvm/Support/FormattedStream.h
+++ b/include/llvm/Support/FormattedStream.h
@@ -85,12 +85,12 @@ public:
   /// underneath it.
   ///
   formatted_raw_ostream(raw_ostream &Stream, bool Delete = false) 
-    : raw_ostream(), TheStream(0), DeleteStream(false), Position(0, 0) {
+    : raw_ostream(), TheStream(nullptr), DeleteStream(false), Position(0, 0) {
     setStream(Stream, Delete);
   }
   explicit formatted_raw_ostream()
-    : raw_ostream(), TheStream(0), DeleteStream(false), Position(0, 0) {
-    Scanned = 0;
+    : raw_ostream(), TheStream(nullptr), DeleteStream(false), Position(0, 0) {
+    Scanned = nullptr;
   }
 
   ~formatted_raw_ostream() {
@@ -114,7 +114,7 @@ public:
       SetUnbuffered();
     TheStream->SetUnbuffered();
 
-    Scanned = 0;
+    Scanned = nullptr;
   }
 
   /// PadToColumn - Align the output to some column number.  If the current
diff --git a/include/llvm/Support/GraphWriter.h b/include/llvm/Support/GraphWriter.h
index 62547ddf0ce..660c519ed64 100644
--- a/include/llvm/Support/GraphWriter.h
+++ b/include/llvm/Support/GraphWriter.h
@@ -259,8 +259,8 @@ public:
 
   /// emitSimpleNode - Outputs a simple (non-record) node
   void emitSimpleNode(const void *ID, const std::string &Attr,
-                      const std::string &Label, unsigned NumEdgeSources = 0,
-                      const std::vector<std::string> *EdgeSourceLabels = 0) {
+                   const std::string &Label, unsigned NumEdgeSources = 0,
+                   const std::vector<std::string> *EdgeSourceLabels = nullptr) {
     O << "\tNode" << ID << "[ ";
     if (!Attr.empty())
       O << Attr << ",";
diff --git a/include/llvm/Support/LEB128.h b/include/llvm/Support/LEB128.h
index 9ef5fe6bef8..ea76c9b5892 100644
--- a/include/llvm/Support/LEB128.h
+++ b/include/llvm/Support/LEB128.h
@@ -77,7 +77,7 @@ inline unsigned encodeULEB128(uint64_t Value, uint8_t *p,
 
 
 /// Utility function to decode a ULEB128 value.
-inline uint64_t decodeULEB128(const uint8_t *p, unsigned *n = 0) {
+inline uint64_t decodeULEB128(const uint8_t *p, unsigned *n = nullptr) {
   const uint8_t *orig_p = p;
   uint64_t Value = 0;
   unsigned Shift = 0;
diff --git a/include/llvm/Support/LineIterator.h b/include/llvm/Support/LineIterator.h
index 7077656da67..e4f9a1c3c1a 100644
--- a/include/llvm/Support/LineIterator.h
+++ b/include/llvm/Support/LineIterator.h
@@ -37,7 +37,7 @@ class line_iterator
 
 public:
   /// \brief Default construct an "end" iterator.
-  line_iterator() : Buffer(0) {}
+  line_iterator() : Buffer(nullptr) {}
 
   /// \brief Construct a new iterator around some memory buffer.
   explicit line_iterator(const MemoryBuffer &Buffer, char CommentMarker = '\0');
diff --git a/include/llvm/Support/ManagedStatic.h b/include/llvm/Support/ManagedStatic.h
index 5587618d11b..1bb8cea092f 100644
--- a/include/llvm/Support/ManagedStatic.h
+++ b/include/llvm/Support/ManagedStatic.h
@@ -47,7 +47,7 @@ protected:
   void RegisterManagedStatic(void *(*creator)(), void (*deleter)(void*)) const;
 public:
   /// isConstructed - Return true if this object has not been created yet.
-  bool isConstructed() const { return Ptr != 0; }
+  bool isConstructed() const { return Ptr != nullptr; }
 
   void destroy() const;
 };
diff --git a/include/llvm/Support/Memory.h b/include/llvm/Support/Memory.h
index 8251fcd96c4..0996adb23f9 100644
--- a/include/llvm/Support/Memory.h
+++ b/include/llvm/Support/Memory.h
@@ -28,7 +28,7 @@ namespace sys {
   /// @brief Memory block abstraction.
   class MemoryBlock {
   public:
-    MemoryBlock() : Address(0), Size(0) { }
+    MemoryBlock() : Address(nullptr), Size(0) { }
     MemoryBlock(void *addr, size_t size) : Address(addr), Size(size) { }
     void *base() const { return Address; }
     size_t size() const { return Size; }
@@ -120,7 +120,7 @@ namespace sys {
     /// @brief Allocate Read/Write/Execute memory.
     static MemoryBlock AllocateRWX(size_t NumBytes,
                                    const MemoryBlock *NearBlock,
-                                   std::string *ErrMsg = 0);
+                                   std::string *ErrMsg = nullptr);
 
     /// This method releases a block of Read/Write/Execute memory that was
     /// allocated with the AllocateRWX method. It should not be used to
@@ -129,7 +129,7 @@ namespace sys {
     /// On success, this returns false, otherwise it returns true and fills
     /// in *ErrMsg.
     /// @brief Release Read/Write/Execute memory.
-    static bool ReleaseRWX(MemoryBlock &block, std::string *ErrMsg = 0);
+    static bool ReleaseRWX(MemoryBlock &block, std::string *ErrMsg = nullptr);
 
 
     /// InvalidateInstructionCache - Before the JIT can run a block of code
@@ -140,12 +140,12 @@ namespace sys {
     /// setExecutable - Before the JIT can run a block of code, it has to be
     /// given read and executable privilege. Return true if it is already r-x
     /// or the system is able to change its previlege.
-    static bool setExecutable(MemoryBlock &M, std::string *ErrMsg = 0);
+    static bool setExecutable(MemoryBlock &M, std::string *ErrMsg = nullptr);
 
     /// setWritable - When adding to a block of code, the JIT may need
     /// to mark a block of code as RW since the protections are on page
     /// boundaries, and the JIT internal allocations are not page aligned.
-    static bool setWritable(MemoryBlock &M, std::string *ErrMsg = 0);
+    static bool setWritable(MemoryBlock &M, std::string *ErrMsg = nullptr);
 
     /// setRangeExecutable - Mark the page containing a range of addresses
     /// as executable.
diff --git a/include/llvm/Support/Program.h b/include/llvm/Support/Program.h
index a1067a649ce..9160b7dd92b 100644
--- a/include/llvm/Support/Program.h
+++ b/include/llvm/Support/Program.h
@@ -87,11 +87,11 @@ struct ProcessInfo {
       const char **args, ///< A vector of strings that are passed to the
       ///< program.  The first element should be the name of the program.
       ///< The list *must* be terminated by a null char* entry.
-      const char **env = 0, ///< An optional vector of strings to use for
+      const char **env = nullptr, ///< An optional vector of strings to use for
       ///< the program's environment. If not provided, the current program's
       ///< environment will be used.
-      const StringRef **redirects = 0, ///< An optional array of pointers to
-      ///< paths. If the array is null, no redirection is done. The array
+      const StringRef **redirects = nullptr, ///< An optional array of pointers
+      ///< to paths. If the array is null, no redirection is done. The array
       ///< should have a size of at least three. The inferior process's
       ///< stdin(0), stdout(1), and stderr(2) will be redirected to the
       ///< corresponding paths.
@@ -107,11 +107,11 @@ struct ProcessInfo {
       ///< of memory can be allocated by process. If memory usage will be
       ///< higher limit, the child is killed and this call returns. If zero
       ///< - no memory limit.
-      std::string *ErrMsg = 0, ///< If non-zero, provides a pointer to a string
-      ///< instance in which error messages will be returned. If the string
-      ///< is non-empty upon return an error occurred while invoking the
+      std::string *ErrMsg = nullptr, ///< If non-zero, provides a pointer to a
+      ///< string instance in which error messages will be returned. If the
+      ///< string is non-empty upon return an error occurred while invoking the
       ///< program.
-      bool *ExecutionFailed = 0);
+      bool *ExecutionFailed = nullptr);
 
   /// Similar to ExecuteAndWait, but returns immediately.
   /// @returns The \see ProcessInfo of the newly launced process.
@@ -119,9 +119,9 @@ struct ProcessInfo {
   /// Wait until the process finished execution or win32 CloseHandle() API on
   /// ProcessInfo.ProcessHandle to avoid memory leaks.
   ProcessInfo
-  ExecuteNoWait(StringRef Program, const char **args, const char **env = 0,
-                const StringRef **redirects = 0, unsigned memoryLimit = 0,
-                std::string *ErrMsg = 0, bool *ExecutionFailed = 0);
+  ExecuteNoWait(StringRef Program, const char **args, const char **env = nullptr,
+                const StringRef **redirects = nullptr, unsigned memoryLimit = 0,
+                std::string *ErrMsg = nullptr, bool *ExecutionFailed = nullptr);
 
   /// Return true if the given arguments fit within system-specific
   /// argument length limits.
@@ -142,9 +142,9 @@ struct ProcessInfo {
       ///< will perform a non-blocking wait on the child process.
       bool WaitUntilTerminates, ///< If true, ignores \p SecondsToWait and waits
       ///< until child has terminated.
-      std::string *ErrMsg = 0 ///< If non-zero, provides a pointer to a string
-      ///< instance in which error messages will be returned. If the string
-      ///< is non-empty upon return an error occurred while invoking the
+      std::string *ErrMsg = nullptr ///< If non-zero, provides a pointer to a
+      ///< string instance in which error messages will be returned. If the
+      ///< string is non-empty upon return an error occurred while invoking the
       ///< program.
       );
   }
diff --git a/include/llvm/Support/Regex.h b/include/llvm/Support/Regex.h
index 2eea369ee4b..bf533ca1aa6 100644
--- a/include/llvm/Support/Regex.h
+++ b/include/llvm/Support/Regex.h
@@ -55,7 +55,7 @@ namespace llvm {
     Regex(Regex &&regex) {
       preg = regex.preg;
       error = regex.error;
-      regex.preg = NULL;
+      regex.preg = nullptr;
     }
     ~Regex();
 
@@ -75,7 +75,7 @@ namespace llvm {
     /// the first group is always the entire pattern.
     ///
     /// This returns true on a successful match.
-    bool match(StringRef String, SmallVectorImpl<StringRef> *Matches = 0);
+    bool match(StringRef String, SmallVectorImpl<StringRef> *Matches = nullptr);
 
     /// sub - Return the result of replacing the first match of the regex in
     /// \p String with the \p Repl string. Backreferences like "\0" in the
@@ -87,7 +87,8 @@ namespace llvm {
     /// \param Error If non-null, any errors in the substitution (invalid
     /// backreferences, trailing backslashes) will be recorded as a non-empty
     /// string.
-    std::string sub(StringRef Repl, StringRef String, std::string *Error = 0);
+    std::string sub(StringRef Repl, StringRef String,
+                    std::string *Error = nullptr);
 
     /// \brief If this function returns true, ^Str$ is an extended regular
     /// expression that matches Str and only Str.
diff --git a/include/llvm/Support/SMLoc.h b/include/llvm/Support/SMLoc.h
index 0906471f624..d5b4c57a8fd 100644
--- a/include/llvm/Support/SMLoc.h
+++ b/include/llvm/Support/SMLoc.h
@@ -23,9 +23,9 @@ namespace llvm {
 class SMLoc {
   const char *Ptr;
 public:
-  SMLoc() : Ptr(0) {}
+  SMLoc() : Ptr(nullptr) {}
 
-  bool isValid() const { return Ptr != 0; }
+  bool isValid() const { return Ptr != nullptr; }
 
   bool operator==(const SMLoc &RHS) const { return RHS.Ptr == Ptr; }
   bool operator!=(const SMLoc &RHS) const { return RHS.Ptr != Ptr; }
diff --git a/include/llvm/Support/Signals.h b/include/llvm/Support/Signals.h
index 58ed175dc22..6cbc1f6854a 100644
--- a/include/llvm/Support/Signals.h
+++ b/include/llvm/Support/Signals.h
@@ -28,7 +28,7 @@ namespace sys {
   /// This function registers signal handlers to ensure that if a signal gets
   /// delivered that the named file is removed.
   /// @brief Remove a file if a fatal signal occurs.
-  bool RemoveFileOnSignal(StringRef Filename, std::string* ErrMsg = 0);
+  bool RemoveFileOnSignal(StringRef Filename, std::string* ErrMsg = nullptr);
 
   /// This function removes a file from the list of files to be removed on
   /// signal delivery.
diff --git a/include/llvm/Support/SourceMgr.h b/include/llvm/Support/SourceMgr.h
index dd4897432d9..39f896d65db 100644
--- a/include/llvm/Support/SourceMgr.h
+++ b/include/llvm/Support/SourceMgr.h
@@ -71,7 +71,8 @@ private:
   SourceMgr(const SourceMgr&) LLVM_DELETED_FUNCTION;
   void operator=(const SourceMgr&) LLVM_DELETED_FUNCTION;
 public:
-  SourceMgr() : LineNoCache(0), DiagHandler(0), DiagContext(0) {}
+  SourceMgr()
+    : LineNoCache(nullptr), DiagHandler(nullptr), DiagContext(nullptr) {}
   ~SourceMgr();
 
   void setIncludeDirs(const std::vector<std::string> &Dirs) {
@@ -80,7 +81,7 @@ public:
 
   /// setDiagHandler - Specify a diagnostic handler to be invoked every time
   /// PrintMessage is called. Ctx is passed into the handler when it is invoked.
-  void setDiagHandler(DiagHandlerTy DH, void *Ctx = 0) {
+  void setDiagHandler(DiagHandlerTy DH, void *Ctx = nullptr) {
     DiagHandler = DH;
     DiagContext = Ctx;
   }
@@ -222,10 +223,10 @@ class SMDiagnostic {
 public:
   // Null diagnostic.
   SMDiagnostic()
-    : SM(0), LineNo(0), ColumnNo(0), Kind(SourceMgr::DK_Error) {}
+    : SM(nullptr), LineNo(0), ColumnNo(0), Kind(SourceMgr::DK_Error) {}
   // Diagnostic with no location (e.g. file not found, command line arg error).
   SMDiagnostic(StringRef filename, SourceMgr::DiagKind Knd, StringRef Msg)
-    : SM(0), Filename(filename), LineNo(-1), ColumnNo(-1), Kind(Knd),
+    : SM(nullptr), Filename(filename), LineNo(-1), ColumnNo(-1), Kind(Knd),
       Message(Msg) {}
 
   // Diagnostic with a location.
diff --git a/include/llvm/Support/StreamableMemoryObject.h b/include/llvm/Support/StreamableMemoryObject.h
index 0259630c8a2..9c9e55c0a75 100644
--- a/include/llvm/Support/StreamableMemoryObject.h
+++ b/include/llvm/Support/StreamableMemoryObject.h
@@ -116,7 +116,7 @@ public:
     // the memory doesn't go away/get reallocated, but it's
     // not currently necessary. Users that need the pointer don't stream.
     assert(0 && "getPointer in streaming memory objects not allowed");
-    return NULL;
+    return nullptr;
   }
   bool isValidAddress(uint64_t address) const override;
   bool isObjectEnd(uint64_t address) const override;
diff --git a/include/llvm/Support/StringPool.h b/include/llvm/Support/StringPool.h
index 71adbc5342e..7e1394cb233 100644
--- a/include/llvm/Support/StringPool.h
+++ b/include/llvm/Support/StringPool.h
@@ -48,7 +48,7 @@ namespace llvm {
       unsigned Refcount; ///< Number of referencing PooledStringPtrs.
 
     public:
-      PooledString() : Pool(0), Refcount(0) { }
+      PooledString() : Pool(nullptr), Refcount(0) { }
     };
 
     friend class PooledStringPtr;
@@ -81,7 +81,7 @@ namespace llvm {
     entry_t *S;
 
   public:
-    PooledStringPtr() : S(0) {}
+    PooledStringPtr() : S(nullptr) {}
 
     explicit PooledStringPtr(entry_t *E) : S(E) {
       if (S) ++S->getValue().Refcount;
@@ -107,7 +107,7 @@ namespace llvm {
         S->getValue().Pool->InternTable.remove(S);
         S->Destroy();
       }
-      S = 0;
+      S = nullptr;
     }
 
     ~PooledStringPtr() { clear(); }
@@ -128,7 +128,7 @@ namespace llvm {
     }
 
     inline const char *operator*() const { return begin(); }
-    inline operator bool() const { return S != 0; }
+    inline operator bool() const { return S != nullptr; }
 
     inline bool operator==(const PooledStringPtr &That) { return S == That.S; }
     inline bool operator!=(const PooledStringPtr &That) { return S != That.S; }
diff --git a/include/llvm/Support/TargetRegistry.h b/include/llvm/Support/TargetRegistry.h
index 8e7478c1558..162749a9e35 100644
--- a/include/llvm/Support/TargetRegistry.h
+++ b/include/llvm/Support/TargetRegistry.h
@@ -233,8 +233,8 @@ namespace llvm {
 
   public:
     Target()
-        : AsmStreamerCtorFn(0), MCRelocationInfoCtorFn(0),
-          MCSymbolizerCtorFn(0) {}
+        : AsmStreamerCtorFn(nullptr), MCRelocationInfoCtorFn(nullptr),
+          MCSymbolizerCtorFn(nullptr) {}
 
     /// @name Target Information
     /// @{
@@ -256,10 +256,10 @@ namespace llvm {
     bool hasJIT() const { return HasJIT; }
 
     /// hasTargetMachine - Check if this target supports code generation.
-    bool hasTargetMachine() const { return TargetMachineCtorFn != 0; }
+    bool hasTargetMachine() const { return TargetMachineCtorFn != nullptr; }
 
     /// hasMCAsmBackend - Check if this target supports .o generation.
-    bool hasMCAsmBackend() const { return MCAsmBackendCtorFn != 0; }
+    bool hasMCAsmBackend() const { return MCAsmBackendCtorFn != nullptr; }
 
     /// @}
     /// @name Feature Constructors
@@ -275,7 +275,7 @@ namespace llvm {
     MCAsmInfo *createMCAsmInfo(const MCRegisterInfo &MRI,
                                StringRef Triple) const {
       if (!MCAsmInfoCtorFn)
-        return 0;
+        return nullptr;
       return MCAsmInfoCtorFn(MRI, Triple);
     }
 
@@ -285,7 +285,7 @@ namespace llvm {
                                        CodeModel::Model CM,
                                        CodeGenOpt::Level OL) const {
       if (!MCCodeGenInfoCtorFn)
-        return 0;
+        return nullptr;
       return MCCodeGenInfoCtorFn(Triple, RM, CM, OL);
     }
 
@@ -293,7 +293,7 @@ namespace llvm {
     ///
     MCInstrInfo *createMCInstrInfo() const {
       if (!MCInstrInfoCtorFn)
-        return 0;
+        return nullptr;
       return MCInstrInfoCtorFn();
     }
 
@@ -301,7 +301,7 @@ namespace llvm {
     ///
     MCInstrAnalysis *createMCInstrAnalysis(const MCInstrInfo *Info) const {
       if (!MCInstrAnalysisCtorFn)
-        return 0;
+        return nullptr;
       return MCInstrAnalysisCtorFn(Info);
     }
 
@@ -309,7 +309,7 @@ namespace llvm {
     ///
     MCRegisterInfo *createMCRegInfo(StringRef Triple) const {
       if (!MCRegInfoCtorFn)
-        return 0;
+        return nullptr;
       return MCRegInfoCtorFn(Triple);
     }
 
@@ -325,7 +325,7 @@ namespace llvm {
     MCSubtargetInfo *createMCSubtargetInfo(StringRef Triple, StringRef CPU,
                                            StringRef Features) const {
       if (!MCSubtargetInfoCtorFn)
-        return 0;
+        return nullptr;
       return MCSubtargetInfoCtorFn(Triple, CPU, Features);
     }
 
@@ -342,7 +342,7 @@ namespace llvm {
                              CodeModel::Model CM = CodeModel::Default,
                              CodeGenOpt::Level OL = CodeGenOpt::Default) const {
       if (!TargetMachineCtorFn)
-        return 0;
+        return nullptr;
       return TargetMachineCtorFn(*this, Triple, CPU, Features, Options,
                                  RM, CM, OL);
     }
@@ -353,7 +353,7 @@ namespace llvm {
     MCAsmBackend *createMCAsmBackend(const MCRegisterInfo &MRI,
                                      StringRef Triple, StringRef CPU) const {
       if (!MCAsmBackendCtorFn)
-        return 0;
+        return nullptr;
       return MCAsmBackendCtorFn(*this, MRI, Triple, CPU);
     }
 
@@ -365,7 +365,7 @@ namespace llvm {
                                          MCAsmParser &Parser,
                                          const MCInstrInfo &MII) const {
       if (!MCAsmParserCtorFn)
-        return 0;
+        return nullptr;
       return MCAsmParserCtorFn(STI, Parser, MII);
     }
 
@@ -373,13 +373,13 @@ namespace llvm {
     /// takes ownership of the MCStreamer object.
     AsmPrinter *createAsmPrinter(TargetMachine &TM, MCStreamer &Streamer) const{
       if (!AsmPrinterCtorFn)
-        return 0;
+        return nullptr;
       return AsmPrinterCtorFn(TM, Streamer);
     }
 
     MCDisassembler *createMCDisassembler(const MCSubtargetInfo &STI) const {
       if (!MCDisassemblerCtorFn)
-        return 0;
+        return nullptr;
       return MCDisassemblerCtorFn(*this, STI);
     }
 
@@ -389,7 +389,7 @@ namespace llvm {
                                        const MCRegisterInfo &MRI,
                                        const MCSubtargetInfo &STI) const {
       if (!MCInstPrinterCtorFn)
-        return 0;
+        return nullptr;
       return MCInstPrinterCtorFn(*this, SyntaxVariant, MAI, MII, MRI, STI);
     }
 
@@ -400,7 +400,7 @@ namespace llvm {
                                        const MCSubtargetInfo &STI,
                                        MCContext &Ctx) const {
       if (!MCCodeEmitterCtorFn)
-        return 0;
+        return nullptr;
       return MCCodeEmitterCtorFn(II, MRI, STI, Ctx);
     }
 
@@ -421,7 +421,7 @@ namespace llvm {
                                        bool RelaxAll,
                                        bool NoExecStack) const {
       if (!MCObjectStreamerCtorFn)
-        return 0;
+        return nullptr;
       return MCObjectStreamerCtorFn(*this, TT, Ctx, TAB, _OS, _Emitter, STI,
                                     RelaxAll, NoExecStack);
     }
@@ -486,7 +486,7 @@ namespace llvm {
       explicit iterator(Target *T) : Current(T) {}
       friend struct TargetRegistry;
     public:
-      iterator() : Current(0) {}
+      iterator() : Current(nullptr) {}
 
       bool operator==(const iterator &x) const {
         return Current == x.Current;
diff --git a/include/llvm/Support/Timer.h b/include/llvm/Support/Timer.h
index d009d7fae51..c9c1fd3f417 100644
--- a/include/llvm/Support/Timer.h
+++ b/include/llvm/Support/Timer.h
@@ -85,9 +85,9 @@ class Timer {
   
   Timer **Prev, *Next;   // Doubly linked list of timers in the group.
 public:
-  explicit Timer(StringRef N) : TG(0) { init(N); }
-  Timer(StringRef N, TimerGroup &tg) : TG(0) { init(N, tg); }
-  Timer(const Timer &RHS) : TG(0) {
+  explicit Timer(StringRef N) : TG(nullptr) { init(N); }
+  Timer(StringRef N, TimerGroup &tg) : TG(nullptr) { init(N, tg); }
+  Timer(const Timer &RHS) : TG(nullptr) {
     assert(RHS.TG == 0 && "Can only copy uninitialized timers");
   }
   const Timer &operator=(const Timer &T) {
@@ -97,12 +97,12 @@ public:
   ~Timer();
 
   // Create an uninitialized timer, client must use 'init'.
-  explicit Timer() : TG(0) {}
+  explicit Timer() : TG(nullptr) {}
   void init(StringRef N);
   void init(StringRef N, TimerGroup &tg);
   
   const std::string &getName() const { return Name; }
-  bool isInitialized() const { return TG != 0; }
+  bool isInitialized() const { return TG != nullptr; }
   
   /// startTimer - Start the timer running.  Time between calls to
   /// startTimer/stopTimer is counted by the Timer class.  Note that these calls
diff --git a/include/llvm/Support/YAMLParser.h b/include/llvm/Support/YAMLParser.h
index 5194b52c3e6..cbe154464f3 100644
--- a/include/llvm/Support/YAMLParser.h
+++ b/include/llvm/Support/YAMLParser.h
@@ -235,7 +235,8 @@ class KeyValueNode : public Node {
   void anchor() override;
 public:
   KeyValueNode(std::unique_ptr<Document> &D)
-      : Node(NK_KeyValue, D, StringRef(), StringRef()), Key(0), Value(0) {}
+    : Node(NK_KeyValue, D, StringRef(), StringRef()), Key(nullptr),
+      Value(nullptr) {}
 
   /// @brief Parse and return the key.
   ///
@@ -274,7 +275,7 @@ template <class BaseT, class ValueT>
 class basic_collection_iterator
   : public std::iterator<std::forward_iterator_tag, ValueT> {
 public:
-  basic_collection_iterator() : Base(0) {}
+  basic_collection_iterator() : Base(nullptr) {}
   basic_collection_iterator(BaseT *B) : Base(B) {}
 
   ValueT *operator ->() const {
@@ -304,8 +305,8 @@ public:
     assert(Base && "Attempted to advance iterator past end!");
     Base->increment();
     // Create an end iterator.
-    if (Base->CurrentEntry == 0)
-      Base = 0;
+    if (Base->CurrentEntry == nullptr)
+      Base = nullptr;
     return *this;
   }
 
@@ -352,7 +353,7 @@ public:
   MappingNode(std::unique_ptr<Document> &D, StringRef Anchor, StringRef Tag,
               MappingType MT)
       : Node(NK_Mapping, D, Anchor, Tag), Type(MT), IsAtBeginning(true),
-        IsAtEnd(false), CurrentEntry(0) {}
+        IsAtEnd(false), CurrentEntry(nullptr) {}
 
   friend class basic_collection_iterator<MappingNode, KeyValueNode>;
   typedef basic_collection_iterator<MappingNode, KeyValueNode> iterator;
@@ -411,7 +412,7 @@ public:
       : Node(NK_Sequence, D, Anchor, Tag), SeqType(ST), IsAtBeginning(true),
         IsAtEnd(false),
         WasPreviousTokenFlowEntry(true), // Start with an imaginary ','.
-        CurrentEntry(0) {}
+        CurrentEntry(nullptr) {}
 
   friend class basic_collection_iterator<SequenceNode, Node>;
   typedef basic_collection_iterator<SequenceNode, Node> iterator;
@@ -526,7 +527,7 @@ private:
 /// @brief Iterator abstraction for Documents over a Stream.
 class document_iterator {
 public:
-  document_iterator() : Doc(0) {}
+  document_iterator() : Doc(nullptr) {}
   document_iterator(std::unique_ptr<Document> &D) : Doc(&D) {}
 
   bool operator ==(const document_iterator &Other) {
@@ -542,7 +543,7 @@ public:
   document_iterator operator ++() {
     assert(Doc != 0 && "incrementing iterator past the end.");
     if (!(*Doc)->skip()) {
-      Doc->reset(0);
+      Doc->reset(nullptr);
     } else {
       Stream &S = (*Doc)->stream;
       Doc->reset(new Document(S));
diff --git a/include/llvm/Support/YAMLTraits.h b/include/llvm/Support/YAMLTraits.h
index ea217c39fca..774438d95e5 100644
--- a/include/llvm/Support/YAMLTraits.h
+++ b/include/llvm/Support/YAMLTraits.h
@@ -207,7 +207,8 @@ struct has_ScalarTraits
   static double test(...);
 
 public:
-  static bool const value = (sizeof(test<ScalarTraits<T> >(0,0)) == 1);
+  static bool const value =
+    (sizeof(test<ScalarTraits<T> >(nullptr,nullptr)) == 1);
 };
 
 
@@ -340,7 +341,7 @@ struct unvalidatedMappingTraits : public std::integral_constant<bool,
 class IO {
 public:
 
-  IO(void *Ctxt=NULL);
+  IO(void *Ctxt=nullptr);
   virtual ~IO();
 
   virtual bool outputting() = 0;
@@ -765,9 +766,9 @@ public:
   // user-data. The DiagHandler can be specified to provide
   // alternative error reporting.
   Input(StringRef InputContent,
-        void *Ctxt = NULL,
-        SourceMgr::DiagHandlerTy DiagHandler = NULL,
-        void *DiagHandlerCtxt = NULL);
+        void *Ctxt = nullptr,
+        SourceMgr::DiagHandlerTy DiagHandler = nullptr,
+        void *DiagHandlerCtxt = nullptr);
   ~Input();
 
   // Check if there was an syntax or semantic error during parsing.
@@ -896,7 +897,7 @@ private:
 ///
 class Output : public IO {
 public:
-  Output(llvm::raw_ostream &, void *Ctxt=NULL);
+  Output(llvm::raw_ostream &, void *Ctxt=nullptr);
   virtual ~Output();
 
   bool outputting() override;
diff --git a/include/llvm/Support/circular_raw_ostream.h b/include/llvm/Support/circular_raw_ostream.h
index 31141990b55..ee7b89fe8c8 100644
--- a/include/llvm/Support/circular_raw_ostream.h
+++ b/include/llvm/Support/circular_raw_ostream.h
@@ -109,10 +109,10 @@ namespace llvm
     circular_raw_ostream(raw_ostream &Stream, const char *Header,
                          size_t BuffSize = 0, bool Owns = REFERENCE_ONLY) 
         : raw_ostream(/*unbuffered*/true),
-            TheStream(0),
+            TheStream(nullptr),
             OwnsStream(Owns),
             BufferSize(BuffSize),
-            BufferArray(0),
+            BufferArray(nullptr),
             Filled(false),
             Banner(Header) {
       if (BufferSize != 0)
@@ -122,9 +122,9 @@ namespace llvm
     }
     explicit circular_raw_ostream()
         : raw_ostream(/*unbuffered*/true),
-            TheStream(0),
+            TheStream(nullptr),
             OwnsStream(REFERENCE_ONLY),
-            BufferArray(0),
+            BufferArray(nullptr),
             Filled(false),
             Banner("") {
       Cur = BufferArray;
diff --git a/include/llvm/Support/raw_ostream.h b/include/llvm/Support/raw_ostream.h
index 0240035b024..a0f2c7798fb 100644
--- a/include/llvm/Support/raw_ostream.h
+++ b/include/llvm/Support/raw_ostream.h
@@ -76,7 +76,7 @@ public:
   explicit raw_ostream(bool unbuffered=false)
     : BufferMode(unbuffered ? Unbuffered : InternalBuffer) {
     // Start out ready to flush.
-    OutBufStart = OutBufEnd = OutBufCur = 0;
+    OutBufStart = OutBufEnd = OutBufCur = nullptr;
   }
 
   virtual ~raw_ostream();
@@ -102,7 +102,7 @@ public:
   size_t GetBufferSize() const {
     // If we're supposed to be buffered but haven't actually gotten around
     // to allocating the buffer yet, return the value that would be used.
-    if (BufferMode != Unbuffered && OutBufStart == 0)
+    if (BufferMode != Unbuffered && OutBufStart == nullptr)
       return preferred_buffer_size();
 
     // Otherwise just return the size of the allocated buffer.
@@ -115,7 +115,7 @@ public:
   /// set to unbuffered.
   void SetUnbuffered() {
     flush();
-    SetBufferAndMode(0, 0, Unbuffered);
+    SetBufferAndMode(nullptr, 0, Unbuffered);
   }
 
   size_t GetNumBytesInBuffer() const {
diff --git a/include/llvm/Support/system_error.h b/include/llvm/Support/system_error.h
index 4ca4b069748..aa5e9f710ae 100644
--- a/include/llvm/Support/system_error.h
+++ b/include/llvm/Support/system_error.h
@@ -706,7 +706,7 @@ public:
   static void unspecified_bool_true() {}
 
   operator unspecified_bool_type() const { // true if error
-    return _val_ == 0 ? 0 : unspecified_bool_true;
+    return _val_ == 0 ? nullptr : unspecified_bool_true;
   }
 };
 
@@ -771,7 +771,7 @@ public:
   static void unspecified_bool_true() {}
 
   operator unspecified_bool_type() const { // true if error
-    return _val_ == 0 ? 0 : unspecified_bool_true;
+    return _val_ == 0 ? nullptr : unspecified_bool_true;
   }
 };
 
diff --git a/lib/Support/APFloat.cpp b/lib/Support/APFloat.cpp
index 85ce31bcabc..e1fd3c602b7 100644
--- a/lib/Support/APFloat.cpp
+++ b/lib/Support/APFloat.cpp
@@ -1679,7 +1679,7 @@ APFloat::multiply(const APFloat &rhs, roundingMode rounding_mode)
   fs = multiplySpecials(rhs);
 
   if (isFiniteNonZero()) {
-    lostFraction lost_fraction = multiplySignificand(rhs, 0);
+    lostFraction lost_fraction = multiplySignificand(rhs, nullptr);
     fs = normalize(rounding_mode, lost_fraction);
     if (lost_fraction != lfExactlyZero)
       fs = (opStatus) (fs | opInexact);
@@ -2439,7 +2439,7 @@ APFloat::roundSignificandWithExponent(const integerPart *decSigParts,
 
     if (exp >= 0) {
       /* multiplySignificand leaves the precision-th bit set to 1.  */
-      calcLostFraction = decSig.multiplySignificand(pow5, NULL);
+      calcLostFraction = decSig.multiplySignificand(pow5, nullptr);
       powHUerr = powStatus != opOK;
     } else {
       calcLostFraction = decSig.divideSignificand(pow5);
@@ -3795,7 +3795,7 @@ APFloat::opStatus APFloat::next(bool nextDown) {
     if (isSignaling()) {
       result = opInvalidOp;
       // For consistency, propagate the sign of the sNaN to the qNaN.
-      makeNaN(false, isNegative(), 0);
+      makeNaN(false, isNegative(), nullptr);
     }
     break;
   case fcZero:
diff --git a/lib/Support/APInt.cpp b/lib/Support/APInt.cpp
index 0c4672582bf..6dafe9ec3c3 100644
--- a/lib/Support/APInt.cpp
+++ b/lib/Support/APInt.cpp
@@ -1683,10 +1683,10 @@ void APInt::divide(const APInt LHS, unsigned lhsWords,
   // Allocate space for the temporary values we need either on the stack, if
   // it will fit, or on the heap if it won't.
   unsigned SPACE[128];
-  unsigned *U = 0;
-  unsigned *V = 0;
-  unsigned *Q = 0;
-  unsigned *R = 0;
+  unsigned *U = nullptr;
+  unsigned *V = nullptr;
+  unsigned *Q = nullptr;
+  unsigned *R = nullptr;
   if ((Remainder?4:3)*n+2*m+1 <= 128) {
     U = &SPACE[0];
     V = &SPACE[m+n+1];
@@ -1872,7 +1872,7 @@ APInt APInt::udiv(const APInt& RHS) const {
 
   // We have to compute it the hard way. Invoke the Knuth divide algorithm.
   APInt Quotient(1,0); // to hold result.
-  divide(*this, lhsWords, RHS, rhsWords, &Quotient, 0);
+  divide(*this, lhsWords, RHS, rhsWords, &Quotient, nullptr);
   return Quotient;
 }
 
@@ -1920,7 +1920,7 @@ APInt APInt::urem(const APInt& RHS) const {
 
   // We have to compute it the hard way. Invoke the Knuth divide algorithm.
   APInt Remainder(1,0);
-  divide(*this, lhsWords, RHS, rhsWords, 0, &Remainder);
+  divide(*this, lhsWords, RHS, rhsWords, nullptr, &Remainder);
   return Remainder;
 }
 
diff --git a/lib/Support/Allocator.cpp b/lib/Support/Allocator.cpp
index 7e177481cb5..11f7ba80a6f 100644
--- a/lib/Support/Allocator.cpp
+++ b/lib/Support/Allocator.cpp
@@ -28,7 +28,7 @@ MallocSlabAllocator::~MallocSlabAllocator() { }
 MemSlab *MallocSlabAllocator::Allocate(size_t Size) {
   MemSlab *Slab = (MemSlab*)Allocator.Allocate(Size, 0);
   Slab->Size = Size;
-  Slab->NextPtr = 0;
+  Slab->NextPtr = nullptr;
   return Slab;
 }
 
@@ -39,7 +39,7 @@ void MallocSlabAllocator::Deallocate(MemSlab *Slab) {
 void BumpPtrAllocatorBase::PrintStats() const {
   unsigned NumSlabs = 0;
   size_t TotalMemory = 0;
-  for (MemSlab *Slab = CurSlab; Slab != 0; Slab = Slab->NextPtr) {
+  for (MemSlab *Slab = CurSlab; Slab != nullptr; Slab = Slab->NextPtr) {
     TotalMemory += Slab->Size;
     ++NumSlabs;
   }
@@ -53,7 +53,7 @@ void BumpPtrAllocatorBase::PrintStats() const {
 
 size_t BumpPtrAllocatorBase::getTotalMemory() const {
   size_t TotalMemory = 0;
-  for (MemSlab *Slab = CurSlab; Slab != 0; Slab = Slab->NextPtr) {
+  for (MemSlab *Slab = CurSlab; Slab != nullptr; Slab = Slab->NextPtr) {
     TotalMemory += Slab->Size;
   }
   return TotalMemory;
diff --git a/lib/Support/CommandLine.cpp b/lib/Support/CommandLine.cpp
index b3c2614ec96..04a40b46f1f 100644
--- a/lib/Support/CommandLine.cpp
+++ b/lib/Support/CommandLine.cpp
@@ -81,7 +81,7 @@ void StringSaver::anchor() {}
 // Globals for name and overview of program.  Program name is not a string to
 // avoid static ctor/dtor issues.
 static char ProgramName[80] = "<premain>";
-static const char *ProgramOverview = 0;
+static const char *ProgramOverview = nullptr;
 
 // This collects additional help to be printed.
 static ManagedStatic<std::vector<const char*> > MoreHelp;
@@ -100,7 +100,7 @@ void cl::MarkOptionsChanged() {
 
 /// RegisteredOptionList - This is the list of the command line options that
 /// have statically constructed themselves.
-static Option *RegisteredOptionList = 0;
+static Option *RegisteredOptionList = nullptr;
 
 void Option::addArgument() {
   assert(NextRegistered == 0 && "argument multiply registered!");
@@ -144,7 +144,7 @@ static void GetOptionInfo(SmallVectorImpl<Option*> &PositionalOpts,
                           SmallVectorImpl<Option*> &SinkOpts,
                           StringMap<Option*> &OptionsMap) {
   SmallVector<const char*, 16> OptionNames;
-  Option *CAOpt = 0;  // The ConsumeAfter option if it exists.
+  Option *CAOpt = nullptr;  // The ConsumeAfter option if it exists.
   for (Option *O = RegisteredOptionList; O; O = O->getNextRegisteredOption()) {
     // If this option wants to handle multiple option names, get the full set.
     // This handles enum options like "-O1 -O2" etc.
@@ -189,7 +189,7 @@ static void GetOptionInfo(SmallVectorImpl<Option*> &PositionalOpts,
 static Option *LookupOption(StringRef &Arg, StringRef &Value,
                             const StringMap<Option*> &OptionsMap) {
   // Reject all dashes.
-  if (Arg.empty()) return 0;
+  if (Arg.empty()) return nullptr;
 
   size_t EqualPos = Arg.find('=');
 
@@ -197,14 +197,14 @@ static Option *LookupOption(StringRef &Arg, StringRef &Value,
   if (EqualPos == StringRef::npos) {
     // Look up the option.
     StringMap<Option*>::const_iterator I = OptionsMap.find(Arg);
-    return I != OptionsMap.end() ? I->second : 0;
+    return I != OptionsMap.end() ? I->second : nullptr;
   }
 
   // If the argument before the = is a valid option name, we match.  If not,
   // return Arg unmolested.
   StringMap<Option*>::const_iterator I =
     OptionsMap.find(Arg.substr(0, EqualPos));
-  if (I == OptionsMap.end()) return 0;
+  if (I == OptionsMap.end()) return nullptr;
 
   Value = Arg.substr(EqualPos+1);
   Arg = Arg.substr(0, EqualPos);
@@ -219,7 +219,7 @@ static Option *LookupNearestOption(StringRef Arg,
                                    const StringMap<Option*> &OptionsMap,
                                    std::string &NearestString) {
   // Reject all dashes.
-  if (Arg.empty()) return 0;
+  if (Arg.empty()) return nullptr;
 
   // Split on any equal sign.
   std::pair<StringRef, StringRef> SplitArg = Arg.split('=');
@@ -227,7 +227,7 @@ static Option *LookupNearestOption(StringRef Arg,
   StringRef &RHS = SplitArg.second;
 
   // Find the closest match.
-  Option *Best = 0;
+  Option *Best = nullptr;
   unsigned BestDistance = 0;
   for (StringMap<Option*>::const_iterator it = OptionsMap.begin(),
          ie = OptionsMap.end(); it != ie; ++it) {
@@ -300,7 +300,7 @@ static inline bool ProvideOption(Option *Handler, StringRef ArgName,
   // Enforce value requirements
   switch (Handler->getValueExpectedFlag()) {
   case ValueRequired:
-    if (Value.data() == 0) {       // No value specified?
+    if (Value.data() == nullptr) { // No value specified?
       if (i+1 >= argc)
         return Handler->error("requires a value!");
       // Steal the next argument, like for '-o filename'
@@ -349,7 +349,7 @@ static inline bool ProvideOption(Option *Handler, StringRef ArgName,
 
 static bool ProvidePositionalOption(Option *Handler, StringRef Arg, int i) {
   int Dummy = i;
-  return ProvideOption(Handler, Handler->ArgStr, Arg, 0, 0, Dummy);
+  return ProvideOption(Handler, Handler->ArgStr, Arg, 0, nullptr, Dummy);
 }
 
 
@@ -385,7 +385,7 @@ static Option *getOptionPred(StringRef Name, size_t &Length,
     Length = Name.size();
     return OMI->second;    // Found one!
   }
-  return 0;                // No option found!
+  return nullptr;          // No option found!
 }
 
 /// HandlePrefixedOrGroupedOption - The specified argument string (which started
@@ -395,12 +395,12 @@ static Option *getOptionPred(StringRef Name, size_t &Length,
 static Option *HandlePrefixedOrGroupedOption(StringRef &Arg, StringRef &Value,
                                              bool &ErrorParsing,
                                          const StringMap<Option*> &OptionsMap) {
-  if (Arg.size() == 1) return 0;
+  if (Arg.size() == 1) return nullptr;
 
   // Do the lookup!
   size_t Length = 0;
   Option *PGOpt = getOptionPred(Arg, Length, isPrefixedOrGrouping, OptionsMap);
-  if (PGOpt == 0) return 0;
+  if (PGOpt == nullptr) return nullptr;
 
   // If the option is a prefixed option, then the value is simply the
   // rest of the name...  so fall through to later processing, by
@@ -427,7 +427,7 @@ static Option *HandlePrefixedOrGroupedOption(StringRef &Arg, StringRef &Value,
            "Option can not be cl::Grouping AND cl::ValueRequired!");
     int Dummy = 0;
     ErrorParsing |= ProvideOption(PGOpt, OneArgName,
-                                  StringRef(), 0, 0, Dummy);
+                                  StringRef(), 0, nullptr, Dummy);
 
     // Get the next grouping option.
     PGOpt = getOptionPred(Arg, Length, isGrouping, OptionsMap);
@@ -760,7 +760,7 @@ void cl::ParseCommandLineOptions(int argc, const char * const *argv,
   // Determine whether or not there are an unlimited number of positionals
   bool HasUnlimitedPositionals = false;
 
-  Option *ConsumeAfterOpt = 0;
+  Option *ConsumeAfterOpt = nullptr;
   if (!PositionalOpts.empty()) {
     if (PositionalOpts[0]->getNumOccurrencesFlag() == cl::ConsumeAfter) {
       assert(PositionalOpts.size() > 1 &&
@@ -770,7 +770,7 @@ void cl::ParseCommandLineOptions(int argc, const char * const *argv,
 
     // Calculate how many positional values are _required_.
     bool UnboundedFound = false;
-    for (size_t i = ConsumeAfterOpt != 0, e = PositionalOpts.size();
+    for (size_t i = ConsumeAfterOpt != nullptr, e = PositionalOpts.size();
          i != e; ++i) {
       Option *Opt = PositionalOpts[i];
       if (RequiresValue(Opt))
@@ -806,13 +806,13 @@ void cl::ParseCommandLineOptions(int argc, const char * const *argv,
   // If the program has named positional arguments, and the name has been run
   // across, keep track of which positional argument was named.  Otherwise put
   // the positional args into the PositionalVals list...
-  Option *ActivePositionalArg = 0;
+  Option *ActivePositionalArg = nullptr;
 
   // Loop over all of the arguments... processing them.
   bool DashDashFound = false;  // Have we read '--'?
   for (int i = 1; i < argc; ++i) {
-    Option *Handler = 0;
-    Option *NearestHandler = 0;
+    Option *Handler = nullptr;
+    Option *NearestHandler = nullptr;
     std::string NearestHandlerString;
     StringRef Value;
     StringRef ArgName = "";
@@ -846,7 +846,7 @@ void cl::ParseCommandLineOptions(int argc, const char * const *argv,
         // the consume after option... if it's specified...
         //
         if (PositionalVals.size() >= NumPositionalRequired &&
-            ConsumeAfterOpt != 0) {
+            ConsumeAfterOpt != nullptr) {
           for (++i; i < argc; ++i)
             PositionalVals.push_back(std::make_pair(argv[i],i));
           break;   // Handle outside of the argument processing loop...
@@ -884,18 +884,18 @@ void cl::ParseCommandLineOptions(int argc, const char * const *argv,
       Handler = LookupOption(ArgName, Value, Opts);
 
       // Check to see if this "option" is really a prefixed or grouped argument.
-      if (Handler == 0)
+      if (Handler == nullptr)
         Handler = HandlePrefixedOrGroupedOption(ArgName, Value,
                                                 ErrorParsing, Opts);
 
       // Otherwise, look for the closest available option to report to the user
       // in the upcoming error.
-      if (Handler == 0 && SinkOpts.empty())
+      if (Handler == nullptr && SinkOpts.empty())
         NearestHandler = LookupNearestOption(ArgName, Opts,
                                              NearestHandlerString);
     }
 
-    if (Handler == 0) {
+    if (Handler == nullptr) {
       if (SinkOpts.empty()) {
         errs() << ProgramName << ": Unknown command line argument '"
              << argv[i] << "'.  Try: '" << argv[0] << " -help'\n";
@@ -939,7 +939,7 @@ void cl::ParseCommandLineOptions(int argc, const char * const *argv,
          << " positional arguments: See: " << argv[0] << " -help\n";
     ErrorParsing = true;
 
-  } else if (ConsumeAfterOpt == 0) {
+  } else if (ConsumeAfterOpt == nullptr) {
     // Positional args have already been handled if ConsumeAfter is specified.
     unsigned ValNo = 0, NumVals = static_cast<unsigned>(PositionalVals.size());
     for (size_t i = 0, e = PositionalOpts.size(); i != e; ++i) {
@@ -1044,7 +1044,7 @@ void cl::ParseCommandLineOptions(int argc, const char * const *argv,
 //
 
 bool Option::error(const Twine &Message, StringRef ArgName) {
-  if (ArgName.data() == 0) ArgName = ArgStr;
+  if (ArgName.data() == nullptr) ArgName = ArgStr;
   if (ArgName.empty())
     errs() << HelpStr;  // Be nice for positional arguments
   else
@@ -1455,12 +1455,12 @@ public:
     outs() << "USAGE: " << ProgramName << " [options]";
 
     // Print out the positional options.
-    Option *CAOpt = 0;   // The cl::ConsumeAfter option, if it exists...
+    Option *CAOpt = nullptr;   // The cl::ConsumeAfter option, if it exists...
     if (!PositionalOpts.empty() &&
         PositionalOpts[0]->getNumOccurrencesFlag() == ConsumeAfter)
       CAOpt = PositionalOpts[0];
 
-    for (size_t i = CAOpt != 0, e = PositionalOpts.size(); i != e; ++i) {
+    for (size_t i = CAOpt != nullptr, e = PositionalOpts.size(); i != e; ++i) {
       if (PositionalOpts[i]->ArgStr[0])
         outs() << " --" << PositionalOpts[i]->ArgStr;
       outs() << " " << PositionalOpts[i]->HelpStr;
@@ -1555,7 +1555,7 @@ protected:
       outs() << (*Category)->getName() << ":\n";
 
       // Check if description is set.
-      if ((*Category)->getDescription() != 0)
+      if ((*Category)->getDescription() != nullptr)
         outs() << (*Category)->getDescription() << "\n\n";
       else
         outs() << "\n";
@@ -1686,9 +1686,9 @@ void cl::PrintOptionValues() {
     Opts[i].second->printOptionValue(MaxArgLen, PrintAllOptions);
 }
 
-static void (*OverrideVersionPrinter)() = 0;
+static void (*OverrideVersionPrinter)() = nullptr;
 
-static std::vector<void (*)()>* ExtraVersionPrinters = 0;
+static std::vector<void (*)()>* ExtraVersionPrinters = nullptr;
 
 namespace {
 class VersionPrinter {
@@ -1721,7 +1721,7 @@ public:
   void operator=(bool OptionWasSpecified) {
     if (!OptionWasSpecified) return;
 
-    if (OverrideVersionPrinter != 0) {
+    if (OverrideVersionPrinter != nullptr) {
       (*OverrideVersionPrinter)();
       exit(0);
     }
@@ -1729,7 +1729,7 @@ public:
 
     // Iterate over any registered extra printers and call them to add further
     // information.
-    if (ExtraVersionPrinters != 0) {
+    if (ExtraVersionPrinters != nullptr) {
       outs() << '\n';
       for (std::vector<void (*)()>::iterator I = ExtraVersionPrinters->begin(),
                                              E = ExtraVersionPrinters->end();
@@ -1779,7 +1779,7 @@ void cl::SetVersionPrinter(void (*func)()) {
 }
 
 void cl::AddExtraVersionPrinter(void (*func)()) {
-  if (ExtraVersionPrinters == 0)
+  if (ExtraVersionPrinters == nullptr)
     ExtraVersionPrinters = new std::vector<void (*)()>;
 
   ExtraVersionPrinters->push_back(func);
diff --git a/lib/Support/CrashRecoveryContext.cpp b/lib/Support/CrashRecoveryContext.cpp
index ccc00894fb3..513875d4de4 100644
--- a/lib/Support/CrashRecoveryContext.cpp
+++ b/lib/Support/CrashRecoveryContext.cpp
@@ -89,16 +89,16 @@ CrashRecoveryContext::~CrashRecoveryContext() {
 }
 
 bool CrashRecoveryContext::isRecoveringFromCrash() {
-  return tlIsRecoveringFromCrash->get() != 0;
+  return tlIsRecoveringFromCrash->get() != nullptr;
 }
 
 CrashRecoveryContext *CrashRecoveryContext::GetCurrent() {
   if (!gCrashRecoveryEnabled)
-    return 0;
+    return nullptr;
 
   const CrashRecoveryContextImpl *CRCI = CurrentContext->get();
   if (!CRCI)
-    return 0;
+    return nullptr;
 
   return CRCI->CRC;
 }
@@ -120,7 +120,7 @@ CrashRecoveryContext::unregisterCleanup(CrashRecoveryContextCleanup *cleanup) {
   if (cleanup == head) {
     head = cleanup->next;
     if (head)
-      head->prev = 0;
+      head->prev = nullptr;
   }
   else {
     cleanup->prev->next = cleanup->next;
@@ -261,7 +261,7 @@ static void CrashRecoverySignalHandler(int Signal) {
   sigset_t SigMask;
   sigemptyset(&SigMask);
   sigaddset(&SigMask, Signal);
-  sigprocmask(SIG_UNBLOCK, &SigMask, 0);
+  sigprocmask(SIG_UNBLOCK, &SigMask, nullptr);
 
   if (CRCI)
     const_cast<CrashRecoveryContextImpl*>(CRCI)->HandleCrash();
@@ -296,7 +296,7 @@ void CrashRecoveryContext::Disable() {
 
   // Restore the previous signal handlers.
   for (unsigned i = 0; i != NumSignals; ++i)
-    sigaction(Signals[i], &PrevActions[i], 0);
+    sigaction(Signals[i], &PrevActions[i], nullptr);
 }
 
 #endif
diff --git a/lib/Support/DataExtractor.cpp b/lib/Support/DataExtractor.cpp
index a564d211b1d..7b829215d29 100644
--- a/lib/Support/DataExtractor.cpp
+++ b/lib/Support/DataExtractor.cpp
@@ -44,7 +44,7 @@ static T *getUs(uint32_t *offset_ptr, T *dst, uint32_t count,
     // success
     return dst;
   }
-  return NULL;
+  return nullptr;
 }
 
 uint8_t DataExtractor::getU8(uint32_t *offset_ptr) const {
@@ -125,7 +125,7 @@ const char *DataExtractor::getCStr(uint32_t *offset_ptr) const {
     *offset_ptr = pos + 1;
     return Data.data() + offset;
   }
-  return NULL;
+  return nullptr;
 }
 
 uint64_t DataExtractor::getULEB128(uint32_t *offset_ptr) const {
diff --git a/lib/Support/DataStream.cpp b/lib/Support/DataStream.cpp
index 1caeddfe24a..cb36d9c0c02 100644
--- a/lib/Support/DataStream.cpp
+++ b/lib/Support/DataStream.cpp
@@ -83,7 +83,7 @@ DataStreamer *getDataFileStreamer(const std::string &Filename,
   if (error_code e = s->OpenFile(Filename)) {
     *StrError = std::string("Could not open ") + Filename + ": " +
         e.message() + "\n";
-    return NULL;
+    return nullptr;
   }
   return s;
 }
diff --git a/lib/Support/Dwarf.cpp b/lib/Support/Dwarf.cpp
index 6604cc73fae..c9efa61afe6 100644
--- a/lib/Support/Dwarf.cpp
+++ b/lib/Support/Dwarf.cpp
@@ -100,7 +100,7 @@ const char *llvm::dwarf::TagString(unsigned Tag) {
     return "DW_TAG_GNU_formal_parameter_pack";
   case DW_TAG_APPLE_property:            return "DW_TAG_APPLE_property";
   }
-  return 0;
+  return nullptr;
 }
 
 /// ChildrenString - Return the string for the specified children flag.
@@ -110,7 +110,7 @@ const char *llvm::dwarf::ChildrenString(unsigned Children) {
   case DW_CHILDREN_no:                   return "DW_CHILDREN_no";
   case DW_CHILDREN_yes:                  return "DW_CHILDREN_yes";
   }
-  return 0;
+  return nullptr;
 }
 
 /// AttributeString - Return the string for the specified attribute.
@@ -271,7 +271,7 @@ const char *llvm::dwarf::AttributeString(unsigned Attribute) {
   case DW_AT_GNU_pubnames:               return "DW_AT_GNU_pubnames";
   case DW_AT_GNU_pubtypes:               return "DW_AT_GNU_pubtypes";
   }
-  return 0;
+  return nullptr;
 }
 
 /// FormEncodingString - Return the string for the specified form encoding.
@@ -308,7 +308,7 @@ const char *llvm::dwarf::FormEncodingString(unsigned Encoding) {
   case DW_FORM_GNU_addr_index:           return "DW_FORM_GNU_addr_index";
   case DW_FORM_GNU_str_index:            return "DW_FORM_GNU_str_index";
   }
-  return 0;
+  return nullptr;
 }
 
 /// OperationEncodingString - Return the string for the specified operation
@@ -477,7 +477,7 @@ const char *llvm::dwarf::OperationEncodingString(unsigned Encoding) {
   case DW_OP_GNU_addr_index:             return "DW_OP_GNU_addr_index";
   case DW_OP_GNU_const_index:            return "DW_OP_GNU_const_index";
   }
-  return 0;
+  return nullptr;
 }
 
 /// AttributeEncodingString - Return the string for the specified attribute
@@ -503,7 +503,7 @@ const char *llvm::dwarf::AttributeEncodingString(unsigned Encoding) {
   case DW_ATE_lo_user:                   return "DW_ATE_lo_user";
   case DW_ATE_hi_user:                   return "DW_ATE_hi_user";
   }
-  return 0;
+  return nullptr;
 }
 
 /// DecimalSignString - Return the string for the specified decimal sign
@@ -516,7 +516,7 @@ const char *llvm::dwarf::DecimalSignString(unsigned Sign) {
   case DW_DS_leading_separate:           return "DW_DS_leading_separate";
   case DW_DS_trailing_separate:          return "DW_DS_trailing_separate";
   }
-  return 0;
+  return nullptr;
 }
 
 /// EndianityString - Return the string for the specified endianity.
@@ -529,7 +529,7 @@ const char *llvm::dwarf::EndianityString(unsigned Endian) {
   case DW_END_lo_user:                   return "DW_END_lo_user";
   case DW_END_hi_user:                   return "DW_END_hi_user";
   }
-  return 0;
+  return nullptr;
 }
 
 /// AccessibilityString - Return the string for the specified accessibility.
@@ -541,7 +541,7 @@ const char *llvm::dwarf::AccessibilityString(unsigned Access) {
   case DW_ACCESS_protected:              return "DW_ACCESS_protected";
   case DW_ACCESS_private:                return "DW_ACCESS_private";
   }
-  return 0;
+  return nullptr;
 }
 
 /// VisibilityString - Return the string for the specified visibility.
@@ -552,7 +552,7 @@ const char *llvm::dwarf::VisibilityString(unsigned Visibility) {
   case DW_VIS_exported:                  return "DW_VIS_exported";
   case DW_VIS_qualified:                 return "DW_VIS_qualified";
   }
-  return 0;
+  return nullptr;
 }
 
 /// VirtualityString - Return the string for the specified virtuality.
@@ -563,7 +563,7 @@ const char *llvm::dwarf::VirtualityString(unsigned Virtuality) {
   case DW_VIRTUALITY_virtual:            return "DW_VIRTUALITY_virtual";
   case DW_VIRTUALITY_pure_virtual:       return "DW_VIRTUALITY_pure_virtual";
   }
-  return 0;
+  return nullptr;
 }
 
 /// LanguageString - Return the string for the specified language.
@@ -600,7 +600,7 @@ const char *llvm::dwarf::LanguageString(unsigned Language) {
   case DW_LANG_lo_user:                  return "DW_LANG_lo_user";
   case DW_LANG_hi_user:                  return "DW_LANG_hi_user";
   }
-  return 0;
+  return nullptr;
 }
 
 /// CaseString - Return the string for the specified identifier case.
@@ -612,7 +612,7 @@ const char *llvm::dwarf::CaseString(unsigned Case) {
   case DW_ID_down_case:                  return "DW_ID_down_case";
   case DW_ID_case_insensitive:           return "DW_ID_case_insensitive";
   }
-  return 0;
+  return nullptr;
 }
 
 /// ConventionString - Return the string for the specified calling convention.
@@ -625,7 +625,7 @@ const char *llvm::dwarf::ConventionString(unsigned Convention) {
    case DW_CC_lo_user:                    return "DW_CC_lo_user";
    case DW_CC_hi_user:                    return "DW_CC_hi_user";
   }
-  return 0;
+  return nullptr;
 }
 
 /// InlineCodeString - Return the string for the specified inline code.
@@ -637,7 +637,7 @@ const char *llvm::dwarf::InlineCodeString(unsigned Code) {
   case DW_INL_declared_not_inlined:      return "DW_INL_declared_not_inlined";
   case DW_INL_declared_inlined:          return "DW_INL_declared_inlined";
   }
-  return 0;
+  return nullptr;
 }
 
 /// ArrayOrderString - Return the string for the specified array order.
@@ -647,7 +647,7 @@ const char *llvm::dwarf::ArrayOrderString(unsigned Order) {
   case DW_ORD_row_major:                 return "DW_ORD_row_major";
   case DW_ORD_col_major:                 return "DW_ORD_col_major";
   }
-  return 0;
+  return nullptr;
 }
 
 /// DiscriminantString - Return the string for the specified discriminant
@@ -657,7 +657,7 @@ const char *llvm::dwarf::DiscriminantString(unsigned Discriminant) {
   case DW_DSC_label:                     return "DW_DSC_label";
   case DW_DSC_range:                     return "DW_DSC_range";
   }
-  return 0;
+  return nullptr;
 }
 
 /// LNStandardString - Return the string for the specified line number standard.
@@ -677,7 +677,7 @@ const char *llvm::dwarf::LNStandardString(unsigned Standard) {
   case DW_LNS_set_epilogue_begin:        return "DW_LNS_set_epilogue_begin";
   case DW_LNS_set_isa:                   return "DW_LNS_set_isa";
   }
-  return 0;
+  return nullptr;
 }
 
 /// LNExtendedString - Return the string for the specified line number extended
@@ -692,7 +692,7 @@ const char *llvm::dwarf::LNExtendedString(unsigned Encoding) {
   case DW_LNE_lo_user:                   return "DW_LNE_lo_user";
   case DW_LNE_hi_user:                   return "DW_LNE_hi_user";
   }
-  return 0;
+  return nullptr;
 }
 
 /// MacinfoString - Return the string for the specified macinfo type encodings.
@@ -706,7 +706,7 @@ const char *llvm::dwarf::MacinfoString(unsigned Encoding) {
   case DW_MACINFO_end_file:              return "DW_MACINFO_end_file";
   case DW_MACINFO_vendor_ext:            return "DW_MACINFO_vendor_ext";
   }
-  return 0;
+  return nullptr;
 }
 
 /// CallFrameString - Return the string for the specified call frame instruction
@@ -745,7 +745,7 @@ const char *llvm::dwarf::CallFrameString(unsigned Encoding) {
   case DW_CFA_lo_user:                   return "DW_CFA_lo_user";
   case DW_CFA_hi_user:                   return "DW_CFA_hi_user";
   }
-  return 0;
+  return nullptr;
 }
 
 const char *llvm::dwarf::AtomTypeString(unsigned AT) {
@@ -761,7 +761,7 @@ const char *llvm::dwarf::AtomTypeString(unsigned AT) {
   case DW_ATOM_type_flags:
     return "DW_ATOM_type_flags";
   }
-  return 0;
+  return nullptr;
 }
 
 const char *llvm::dwarf::GDBIndexEntryKindString(GDBIndexEntryKind Kind) {
diff --git a/lib/Support/DynamicLibrary.cpp b/lib/Support/DynamicLibrary.cpp
index 5d77153a188..e4a438585b8 100644
--- a/lib/Support/DynamicLibrary.cpp
+++ b/lib/Support/DynamicLibrary.cpp
@@ -51,14 +51,14 @@ using namespace llvm::sys;
 //===          independent code.
 //===----------------------------------------------------------------------===//
 
-static DenseSet<void *> *OpenedHandles = 0;
+static DenseSet<void *> *OpenedHandles = nullptr;
 
 DynamicLibrary DynamicLibrary::getPermanentLibrary(const char *filename,
                                                    std::string *errMsg) {
   SmartScopedLock<true> lock(*SymbolsMutex);
 
   void *handle = dlopen(filename, RTLD_LAZY|RTLD_GLOBAL);
-  if (handle == 0) {
+  if (handle == nullptr) {
     if (errMsg) *errMsg = dlerror();
     return DynamicLibrary();
   }
@@ -70,7 +70,7 @@ DynamicLibrary DynamicLibrary::getPermanentLibrary(const char *filename,
     handle = RTLD_DEFAULT;
 #endif
 
-  if (OpenedHandles == 0)
+  if (OpenedHandles == nullptr)
     OpenedHandles = new DenseSet<void *>();
 
   // If we've already loaded this library, dlclose() the handle in order to
@@ -83,7 +83,7 @@ DynamicLibrary DynamicLibrary::getPermanentLibrary(const char *filename,
 
 void *DynamicLibrary::getAddressOfSymbol(const char *symbolName) {
   if (!isValid())
-    return NULL;
+    return nullptr;
   return dlsym(Data, symbolName);
 }
 
@@ -166,7 +166,7 @@ void* DynamicLibrary::SearchForAddressOfSymbol(const char *symbolName) {
 #endif
 #undef EXPLICIT_SYMBOL
 
-  return 0;
+  return nullptr;
 }
 
 #endif // LLVM_ON_WIN32
diff --git a/lib/Support/ErrorHandling.cpp b/lib/Support/ErrorHandling.cpp
index 1aa8303b9e2..342c4f05cc9 100644
--- a/lib/Support/ErrorHandling.cpp
+++ b/lib/Support/ErrorHandling.cpp
@@ -34,8 +34,8 @@
 
 using namespace llvm;
 
-static fatal_error_handler_t ErrorHandler = 0;
-static void *ErrorHandlerUserData = 0;
+static fatal_error_handler_t ErrorHandler = nullptr;
+static void *ErrorHandlerUserData = nullptr;
 
 void llvm::install_fatal_error_handler(fatal_error_handler_t handler,
                                        void *user_data) {
@@ -47,7 +47,7 @@ void llvm::install_fatal_error_handler(fatal_error_handler_t handler,
 }
 
 void llvm::remove_fatal_error_handler() {
-  ErrorHandler = 0;
+  ErrorHandler = nullptr;
 }
 
 void llvm::report_fatal_error(const char *Reason, bool GenCrashDiag) {
diff --git a/lib/Support/FileOutputBuffer.cpp b/lib/Support/FileOutputBuffer.cpp
index 8f2c9fcce08..7e922df1358 100644
--- a/lib/Support/FileOutputBuffer.cpp
+++ b/lib/Support/FileOutputBuffer.cpp
@@ -97,7 +97,7 @@ error_code FileOutputBuffer::create(StringRef FilePath,
 
 error_code FileOutputBuffer::commit(int64_t NewSmallerSize) {
   // Unmap buffer, letting OS flush dirty pages to file on disk.
-  Region.reset(0);
+  Region.reset(nullptr);
 
   // If requested, resize file as part of commit.
   if ( NewSmallerSize != -1 ) {
diff --git a/lib/Support/FoldingSet.cpp b/lib/Support/FoldingSet.cpp
index 145f12dc1e5..0367c7ce45e 100644
--- a/lib/Support/FoldingSet.cpp
+++ b/lib/Support/FoldingSet.cpp
@@ -190,7 +190,7 @@ FoldingSetNodeID::Intern(BumpPtrAllocator &Allocator) const {
 static FoldingSetImpl::Node *GetNextPtr(void *NextInBucketPtr) {
   // The low bit is set if this is the pointer back to the bucket.
   if (reinterpret_cast<intptr_t>(NextInBucketPtr) & 1)
-    return 0;
+    return nullptr;
   
   return static_cast<FoldingSetImpl::Node*>(NextInBucketPtr);
 }
@@ -262,7 +262,7 @@ void FoldingSetImpl::GrowHashTable() {
     while (Node *NodeInBucket = GetNextPtr(Probe)) {
       // Figure out the next link, remove NodeInBucket from the old link.
       Probe = NodeInBucket->getNextInBucket();
-      NodeInBucket->SetNextInBucket(0);
+      NodeInBucket->SetNextInBucket(nullptr);
 
       // Insert the node into the new bucket, after recomputing the hash.
       InsertNode(NodeInBucket,
@@ -285,7 +285,7 @@ FoldingSetImpl::Node
   void **Bucket = GetBucketFor(IDHash, Buckets, NumBuckets);
   void *Probe = *Bucket;
   
-  InsertPos = 0;
+  InsertPos = nullptr;
   
   FoldingSetNodeID TempID;
   while (Node *NodeInBucket = GetNextPtr(Probe)) {
@@ -298,7 +298,7 @@ FoldingSetImpl::Node
   
   // Didn't find the node, return null with the bucket as the InsertPos.
   InsertPos = Bucket;
-  return 0;
+  return nullptr;
 }
 
 /// InsertNode - Insert the specified node into the folding set, knowing that it
@@ -323,7 +323,7 @@ void FoldingSetImpl::InsertNode(Node *N, void *InsertPos) {
   // If this is the first insertion into this bucket, its next pointer will be
   // null.  Pretend as if it pointed to itself, setting the low bit to indicate
   // that it is a pointer to the bucket.
-  if (Next == 0)
+  if (Next == nullptr)
     Next = reinterpret_cast<void*>(reinterpret_cast<intptr_t>(Bucket)|1);
 
   // Set the node's next pointer, and make the bucket point to the node.
@@ -337,10 +337,10 @@ bool FoldingSetImpl::RemoveNode(Node *N) {
   // Because each bucket is a circular list, we don't need to compute N's hash
   // to remove it.
   void *Ptr = N->getNextInBucket();
-  if (Ptr == 0) return false;  // Not in folding set.
+  if (Ptr == nullptr) return false;  // Not in folding set.
 
   --NumNodes;
-  N->SetNextInBucket(0);
+  N->SetNextInBucket(nullptr);
 
   // Remember what N originally pointed to, either a bucket or another node.
   void *NodeNextPtr = Ptr;
@@ -390,7 +390,7 @@ FoldingSetImpl::Node *FoldingSetImpl::GetOrInsertNode(FoldingSetImpl::Node *N) {
 FoldingSetIteratorImpl::FoldingSetIteratorImpl(void **Bucket) {
   // Skip to the first non-null non-self-cycle bucket.
   while (*Bucket != reinterpret_cast<void*>(-1) &&
-         (*Bucket == 0 || GetNextPtr(*Bucket) == 0))
+         (*Bucket == nullptr || GetNextPtr(*Bucket) == nullptr))
     ++Bucket;
   
   NodePtr = static_cast<FoldingSetNode*>(*Bucket);
@@ -410,7 +410,7 @@ void FoldingSetIteratorImpl::advance() {
     do {
       ++Bucket;
     } while (*Bucket != reinterpret_cast<void*>(-1) &&
-             (*Bucket == 0 || GetNextPtr(*Bucket) == 0));
+             (*Bucket == nullptr || GetNextPtr(*Bucket) == nullptr));
     
     NodePtr = static_cast<FoldingSetNode*>(*Bucket);
   }
@@ -420,5 +420,6 @@ void FoldingSetIteratorImpl::advance() {
 // FoldingSetBucketIteratorImpl Implementation
 
 FoldingSetBucketIteratorImpl::FoldingSetBucketIteratorImpl(void **Bucket) {
-  Ptr = (*Bucket == 0 || GetNextPtr(*Bucket) == 0) ? (void*) Bucket : *Bucket;
+  Ptr = (*Bucket == nullptr || GetNextPtr(*Bucket) == nullptr) ? (void*) Bucket
+                                                               : *Bucket;
 }
diff --git a/lib/Support/FormattedStream.cpp b/lib/Support/FormattedStream.cpp
index 9febf664f2b..618ec2673a1 100644
--- a/lib/Support/FormattedStream.cpp
+++ b/lib/Support/FormattedStream.cpp
@@ -81,7 +81,7 @@ void formatted_raw_ostream::write_impl(const char *Ptr, size_t Size) {
   TheStream->write(Ptr, Size);
 
   // Reset the scanning pointer.
-  Scanned = 0;
+  Scanned = nullptr;
 }
 
 /// fouts() - This returns a reference to a formatted_raw_ostream for
diff --git a/lib/Support/GraphWriter.cpp b/lib/Support/GraphWriter.cpp
index 83aa25507f6..f5b2943e86b 100644
--- a/lib/Support/GraphWriter.cpp
+++ b/lib/Support/GraphWriter.cpp
@@ -83,7 +83,7 @@ static bool LLVM_ATTRIBUTE_UNUSED
 ExecGraphViewer(StringRef ExecPath, std::vector<const char*> &args,
                 StringRef Filename, bool wait, std::string &ErrMsg) {
   if (wait) {
-    if (sys::ExecuteAndWait(ExecPath, &args[0],0,0,0,0,&ErrMsg)) {
+    if (sys::ExecuteAndWait(ExecPath, &args[0],nullptr,nullptr,0,0,&ErrMsg)) {
       errs() << "Error: " << ErrMsg << "\n";
       return false;
     }
@@ -91,7 +91,7 @@ ExecGraphViewer(StringRef ExecPath, std::vector<const char*> &args,
     errs() << " done. \n";
   }
   else {
-    sys::ExecuteNoWait(ExecPath, &args[0],0,0,0,&ErrMsg);
+    sys::ExecuteNoWait(ExecPath, &args[0],nullptr,nullptr,0,&ErrMsg);
     errs() << "Remember to erase graph file: " << Filename.str() << "\n";
   }
   return true;
@@ -108,7 +108,7 @@ void llvm::DisplayGraph(StringRef FilenameRef, bool wait,
   std::vector<const char*> args;
   args.push_back(Graphviz.c_str());
   args.push_back(Filename.c_str());
-  args.push_back(0);
+  args.push_back(nullptr);
 
   errs() << "Running 'Graphviz' program... ";
   if (!ExecGraphViewer(Graphviz, args, Filename, wait, ErrMsg))
diff --git a/lib/Support/IntervalMap.cpp b/lib/Support/IntervalMap.cpp
index 4dfcc404ca4..e11a7f2eb84 100644
--- a/lib/Support/IntervalMap.cpp
+++ b/lib/Support/IntervalMap.cpp
@@ -58,7 +58,7 @@ void Path::moveLeft(unsigned Level) {
     }
   } else if (height() < Level)
     // end() may have created a height=0 path.
-    path.resize(Level + 1, Entry(0, 0, 0));
+    path.resize(Level + 1, Entry(nullptr, 0, 0));
 
   // NR is the subtree containing our left sibling.
   --path[l].offset;
diff --git a/lib/Support/LineIterator.cpp b/lib/Support/LineIterator.cpp
index 056d817526c..947a8fb6062 100644
--- a/lib/Support/LineIterator.cpp
+++ b/lib/Support/LineIterator.cpp
@@ -13,9 +13,10 @@
 using namespace llvm;
 
 line_iterator::line_iterator(const MemoryBuffer &Buffer, char CommentMarker)
-    : Buffer(Buffer.getBufferSize() ? &Buffer : 0),
+    : Buffer(Buffer.getBufferSize() ? &Buffer : nullptr),
       CommentMarker(CommentMarker), LineNumber(1),
-      CurrentLine(Buffer.getBufferSize() ? Buffer.getBufferStart() : 0, 0) {
+      CurrentLine(Buffer.getBufferSize() ? Buffer.getBufferStart() : nullptr,
+                  0) {
   // Ensure that if we are constructed on a non-empty memory buffer that it is
   // a null terminated buffer.
   if (Buffer.getBufferSize()) {
@@ -53,7 +54,7 @@ void line_iterator::advance() {
 
   if (*Pos == '\0') {
     // We've hit the end of the buffer, reset ourselves to the end state.
-    Buffer = 0;
+    Buffer = nullptr;
     CurrentLine = StringRef();
     return;
   }
diff --git a/lib/Support/LockFileManager.cpp b/lib/Support/LockFileManager.cpp
index fb07801a14b..9b4bfbe8198 100644
--- a/lib/Support/LockFileManager.cpp
+++ b/lib/Support/LockFileManager.cpp
@@ -196,7 +196,7 @@ LockFileManager::WaitForUnlockResult LockFileManager::waitForUnlock() {
 #if LLVM_ON_WIN32
     Sleep(Interval);
 #else
-    nanosleep(&Interval, NULL);
+    nanosleep(&Interval, nullptr);
 #endif
     bool LockFileJustDisappeared = false;
 
diff --git a/lib/Support/ManagedStatic.cpp b/lib/Support/ManagedStatic.cpp
index 098cccb68df..e358fe8c5c1 100644
--- a/lib/Support/ManagedStatic.cpp
+++ b/lib/Support/ManagedStatic.cpp
@@ -17,15 +17,15 @@
 #include <cassert>
 using namespace llvm;
 
-static const ManagedStaticBase *StaticList = 0;
+static const ManagedStaticBase *StaticList = nullptr;
 
 void ManagedStaticBase::RegisterManagedStatic(void *(*Creator)(),
                                               void (*Deleter)(void*)) const {
   if (llvm_is_multithreaded()) {
     llvm_acquire_global_lock();
 
-    if (Ptr == 0) {
-      void* tmp = Creator ? Creator() : 0;
+    if (Ptr == nullptr) {
+      void* tmp = Creator ? Creator() : nullptr;
 
       TsanHappensBefore(this);
       sys::MemoryFence();
@@ -47,7 +47,7 @@ void ManagedStaticBase::RegisterManagedStatic(void *(*Creator)(),
   } else {
     assert(Ptr == 0 && DeleterFn == 0 && Next == 0 &&
            "Partially initialized ManagedStatic!?");
-    Ptr = Creator ? Creator() : 0;
+    Ptr = Creator ? Creator() : nullptr;
     DeleterFn = Deleter;
   
     // Add to list of managed statics.
@@ -62,14 +62,14 @@ void ManagedStaticBase::destroy() const {
          "Not destroyed in reverse order of construction?");
   // Unlink from list.
   StaticList = Next;
-  Next = 0;
+  Next = nullptr;
 
   // Destroy memory.
   DeleterFn(Ptr);
   
   // Cleanup.
-  Ptr = 0;
-  DeleterFn = 0;
+  Ptr = nullptr;
+  DeleterFn = nullptr;
 }
 
 /// llvm_shutdown - Deallocate and destroy all ManagedStatic variables.
diff --git a/lib/Support/MemoryBuffer.cpp b/lib/Support/MemoryBuffer.cpp
index 2d593a8f414..773ccfd6f73 100644
--- a/lib/Support/MemoryBuffer.cpp
+++ b/lib/Support/MemoryBuffer.cpp
@@ -117,7 +117,7 @@ MemoryBuffer *MemoryBuffer::getMemBuffer(StringRef InputData,
 MemoryBuffer *MemoryBuffer::getMemBufferCopy(StringRef InputData,
                                              StringRef BufferName) {
   MemoryBuffer *Buf = getNewUninitMemBuffer(InputData.size(), BufferName);
-  if (!Buf) return 0;
+  if (!Buf) return nullptr;
   memcpy(const_cast<char*>(Buf->getBufferStart()), InputData.data(),
          InputData.size());
   return Buf;
@@ -137,7 +137,7 @@ MemoryBuffer *MemoryBuffer::getNewUninitMemBuffer(size_t Size,
       RoundUpToAlignment(sizeof(MemoryBufferMem) + BufferName.size() + 1, 16);
   size_t RealLen = AlignedStringLen + Size + 1;
   char *Mem = static_cast<char*>(operator new(RealLen, std::nothrow));
-  if (!Mem) return 0;
+  if (!Mem) return nullptr;
 
   // The name is stored after the class itself.
   CopyStringRef(Mem + sizeof(MemoryBufferMem), BufferName);
@@ -155,7 +155,7 @@ MemoryBuffer *MemoryBuffer::getNewUninitMemBuffer(size_t Size,
 /// the MemoryBuffer object.
 MemoryBuffer *MemoryBuffer::getNewMemBuffer(size_t Size, StringRef BufferName) {
   MemoryBuffer *SB = getNewUninitMemBuffer(Size, BufferName);
-  if (!SB) return 0;
+  if (!SB) return nullptr;
   memset(const_cast<char*>(SB->getBufferStart()), 0, Size);
   return SB;
 }
diff --git a/lib/Support/Mutex.cpp b/lib/Support/Mutex.cpp
index 37c9d73daee..292d32a2fb1 100644
--- a/lib/Support/Mutex.cpp
+++ b/lib/Support/Mutex.cpp
@@ -42,7 +42,7 @@ using namespace sys;
 
 // Construct a Mutex using pthread calls
 MutexImpl::MutexImpl( bool recursive)
-  : data_(0)
+  : data_(nullptr)
 {
   // Declare the pthread_mutex data structures
   pthread_mutex_t* mutex =
diff --git a/lib/Support/Path.cpp b/lib/Support/Path.cpp
index 5b73631d989..d345829d4dd 100644
--- a/lib/Support/Path.cpp
+++ b/lib/Support/Path.cpp
@@ -577,7 +577,7 @@ void system_temp_directory(bool erasedOnReboot, SmallVectorImpl<char> &result) {
   // macros defined in <unistd.h> on darwin >= 9
   int ConfName = erasedOnReboot? _CS_DARWIN_USER_TEMP_DIR
                                : _CS_DARWIN_USER_CACHE_DIR;
-  size_t ConfLen = confstr(ConfName, 0, 0);
+  size_t ConfLen = confstr(ConfName, nullptr, 0);
   if (ConfLen > 0) {
     do {
       result.resize(ConfLen);
diff --git a/lib/Support/PrettyStackTrace.cpp b/lib/Support/PrettyStackTrace.cpp
index d4e205cdb3c..aef02e990a2 100644
--- a/lib/Support/PrettyStackTrace.cpp
+++ b/lib/Support/PrettyStackTrace.cpp
@@ -46,7 +46,7 @@ static unsigned PrintStack(const PrettyStackTraceEntry *Entry, raw_ostream &OS){
 /// PrintCurStackTrace - Print the current stack trace to the specified stream.
 static void PrintCurStackTrace(raw_ostream &OS) {
   // Don't print an empty trace.
-  if (PrettyStackTraceHead->get() == 0) return;
+  if (PrettyStackTraceHead->get() == nullptr) return;
   
   // If there are pretty stack frames registered, walk and emit them.
   OS << "Stack dump:\n";
@@ -136,7 +136,7 @@ void PrettyStackTraceProgram::print(raw_ostream &OS) const {
 }
 
 static bool RegisterCrashPrinter() {
-  sys::AddSignalHandler(CrashHandler, 0);
+  sys::AddSignalHandler(CrashHandler, nullptr);
   return false;
 }
 
diff --git a/lib/Support/RWMutex.cpp b/lib/Support/RWMutex.cpp
index 6a34f2d0852..f42be5af50f 100644
--- a/lib/Support/RWMutex.cpp
+++ b/lib/Support/RWMutex.cpp
@@ -44,7 +44,7 @@ using namespace sys;
 
 // Construct a RWMutex using pthread calls
 RWMutexImpl::RWMutexImpl()
-  : data_(0)
+  : data_(nullptr)
 {
   // Declare the pthread_rwlock data structures
   pthread_rwlock_t* rwlock =
@@ -56,7 +56,7 @@ RWMutexImpl::RWMutexImpl()
 #endif
 
   // Initialize the rwlock
-  int errorcode = pthread_rwlock_init(rwlock, NULL);
+  int errorcode = pthread_rwlock_init(rwlock, nullptr);
   (void)errorcode;
   assert(errorcode == 0);
 
diff --git a/lib/Support/Regex.cpp b/lib/Support/Regex.cpp
index 1115534427c..f7fe1e4c792 100644
--- a/lib/Support/Regex.cpp
+++ b/lib/Support/Regex.cpp
@@ -43,7 +43,7 @@ bool Regex::isValid(std::string &Error) {
   if (!error)
     return true;
   
-  size_t len = llvm_regerror(error, preg, NULL, 0);
+  size_t len = llvm_regerror(error, preg, nullptr, 0);
   
   Error.resize(len - 1);
   llvm_regerror(error, preg, &Error[0], len);
diff --git a/lib/Support/SearchForAddressOfSpecialSymbol.cpp b/lib/Support/SearchForAddressOfSpecialSymbol.cpp
index 2d23902bb85..55f3320f640 100644
--- a/lib/Support/SearchForAddressOfSpecialSymbol.cpp
+++ b/lib/Support/SearchForAddressOfSpecialSymbol.cpp
@@ -48,7 +48,7 @@ static void *DoSearch(const char* symbolName) {
 #endif
 
 #undef EXPLICIT_SYMBOL
-  return 0;
+  return nullptr;
 }
 
 namespace llvm {
diff --git a/lib/Support/SmallPtrSet.cpp b/lib/Support/SmallPtrSet.cpp
index 844e41696f9..a80e095ec35 100644
--- a/lib/Support/SmallPtrSet.cpp
+++ b/lib/Support/SmallPtrSet.cpp
@@ -103,7 +103,7 @@ const void * const *SmallPtrSetImplBase::FindBucketFor(const void *Ptr) const {
   unsigned ArraySize = CurArraySize;
   unsigned ProbeAmt = 1;
   const void *const *Array = CurArray;
-  const void *const *Tombstone = 0;
+  const void *const *Tombstone = nullptr;
   while (1) {
     // Found Ptr's bucket?
     if (Array[Bucket] == Ptr)
diff --git a/lib/Support/SourceMgr.cpp b/lib/Support/SourceMgr.cpp
index 4bfd96abe5b..4aa6ff7d31e 100644
--- a/lib/Support/SourceMgr.cpp
+++ b/lib/Support/SourceMgr.cpp
@@ -114,7 +114,7 @@ SourceMgr::getLineAndColumn(SMLoc Loc, int BufferID) const {
     if (*Ptr == '\n') ++LineNo;
 
   // Allocate the line number cache if it doesn't exist.
-  if (LineNoCache == 0)
+  if (LineNoCache == nullptr)
     LineNoCache = new LineNoCacheTy();
 
   // Update the line # cache.
@@ -228,7 +228,7 @@ void SourceMgr::PrintMessage(raw_ostream &OS, SMLoc Loc,
     PrintIncludeStack(getBufferInfo(CurBuf).IncludeLoc, OS);
   }
 
-  Diagnostic.print(0, OS, ShowColors);
+  Diagnostic.print(nullptr, OS, ShowColors);
 }
 
 void SourceMgr::PrintMessage(SMLoc Loc, SourceMgr::DiagKind Kind,
diff --git a/lib/Support/StringMap.cpp b/lib/Support/StringMap.cpp
index 9ac1f867fdd..30b6abb3b42 100644
--- a/lib/Support/StringMap.cpp
+++ b/lib/Support/StringMap.cpp
@@ -27,7 +27,7 @@ StringMapImpl::StringMapImpl(unsigned InitSize, unsigned itemSize) {
   }
   
   // Otherwise, initialize it with zero buckets to avoid the allocation.
-  TheTable = 0;
+  TheTable = nullptr;
   NumBuckets = 0;
   NumItems = 0;
   NumTombstones = 0;
@@ -70,7 +70,7 @@ unsigned StringMapImpl::LookupBucketFor(StringRef Name) {
   while (1) {
     StringMapEntryBase *BucketItem = TheTable[BucketNo];
     // If we found an empty bucket, this key isn't in the table yet, return it.
-    if (LLVM_LIKELY(BucketItem == 0)) {
+    if (LLVM_LIKELY(BucketItem == nullptr)) {
       // If we found a tombstone, we want to reuse the tombstone instead of an
       // empty bucket.  This reduces probing.
       if (FirstTombstone != -1) {
@@ -124,7 +124,7 @@ int StringMapImpl::FindKey(StringRef Key) const {
   while (1) {
     StringMapEntryBase *BucketItem = TheTable[BucketNo];
     // If we found an empty bucket, this key isn't in the table yet, return.
-    if (LLVM_LIKELY(BucketItem == 0))
+    if (LLVM_LIKELY(BucketItem == nullptr))
       return -1;
     
     if (BucketItem == getTombstoneVal()) {
@@ -166,7 +166,7 @@ void StringMapImpl::RemoveKey(StringMapEntryBase *V) {
 /// table, returning it.  If the key is not in the table, this returns null.
 StringMapEntryBase *StringMapImpl::RemoveKey(StringRef Key) {
   int Bucket = FindKey(Key);
-  if (Bucket == -1) return 0;
+  if (Bucket == -1) return nullptr;
   
   StringMapEntryBase *Result = TheTable[Bucket];
   TheTable[Bucket] = getTombstoneVal();
@@ -212,7 +212,7 @@ void StringMapImpl::RehashTable() {
       // Fast case, bucket available.
       unsigned FullHash = HashTable[I];
       unsigned NewBucket = FullHash & (NewSize-1);
-      if (NewTableArray[NewBucket] == 0) {
+      if (NewTableArray[NewBucket] == nullptr) {
         NewTableArray[FullHash & (NewSize-1)] = Bucket;
         NewHashArray[FullHash & (NewSize-1)] = FullHash;
         continue;
diff --git a/lib/Support/StringRef.cpp b/lib/Support/StringRef.cpp
index bd2a37bb5ef..cde8258dece 100644
--- a/lib/Support/StringRef.cpp
+++ b/lib/Support/StringRef.cpp
@@ -281,7 +281,7 @@ void StringRef::split(SmallVectorImpl<StringRef> &A,
   // rest.data() is used to distinguish cases like "a," that splits into
   // "a" + "" and "a" that splits into "a" + 0.
   for (int splits = 0;
-       rest.data() != NULL && (MaxSplit < 0 || splits < MaxSplit);
+       rest.data() != nullptr && (MaxSplit < 0 || splits < MaxSplit);
        ++splits) {
     std::pair<StringRef, StringRef> p = rest.split(Separators);
 
@@ -290,7 +290,7 @@ void StringRef::split(SmallVectorImpl<StringRef> &A,
     rest = p.second;
   }
   // If we have a tail left, add it.
-  if (rest.data() != NULL && (rest.size() != 0 || KeepEmpty))
+  if (rest.data() != nullptr && (rest.size() != 0 || KeepEmpty))
     A.push_back(rest);
 }
 
diff --git a/lib/Support/TargetRegistry.cpp b/lib/Support/TargetRegistry.cpp
index 8d91a53c226..5b0e4a30a9b 100644
--- a/lib/Support/TargetRegistry.cpp
+++ b/lib/Support/TargetRegistry.cpp
@@ -17,7 +17,7 @@
 using namespace llvm;
 
 // Clients are responsible for avoid race conditions in registration.
-static Target *FirstTarget = 0;
+static Target *FirstTarget = nullptr;
 
 TargetRegistry::iterator TargetRegistry::begin() {
   return iterator(FirstTarget);
@@ -29,7 +29,7 @@ const Target *TargetRegistry::lookupTarget(const std::string &ArchName,
   // Allocate target machine.  First, check whether the user has explicitly
   // specified an architecture to compile for. If so we have to look it up by
   // name, because it might be a backend that has no mapping to a target triple.
-  const Target *TheTarget = 0;
+  const Target *TheTarget = nullptr;
   if (!ArchName.empty()) {
     for (TargetRegistry::iterator it = TargetRegistry::begin(),
            ie = TargetRegistry::end(); it != ie; ++it) {
@@ -41,7 +41,7 @@ const Target *TargetRegistry::lookupTarget(const std::string &ArchName,
 
     if (!TheTarget) {
       Error = "error: invalid target '" + ArchName + "'.\n";
-      return 0;
+      return nullptr;
     }
 
     // Adjust the triple to match (if known), otherwise stick with the
@@ -53,11 +53,11 @@ const Target *TargetRegistry::lookupTarget(const std::string &ArchName,
     // Get the target specific parser.
     std::string TempError;
     TheTarget = TargetRegistry::lookupTarget(TheTriple.getTriple(), TempError);
-    if (TheTarget == 0) {
+    if (TheTarget == nullptr) {
       Error = ": error: unable to get target for '"
             + TheTriple.getTriple()
             + "', see --version and --triple.\n";
-      return 0;
+      return nullptr;
     }
   }
 
@@ -69,16 +69,16 @@ const Target *TargetRegistry::lookupTarget(const std::string &TT,
   // Provide special warning when no targets are initialized.
   if (begin() == end()) {
     Error = "Unable to find target for this triple (no targets are registered)";
-    return 0;
+    return nullptr;
   }
-  const Target *Matching = 0;
+  const Target *Matching = nullptr;
   Triple::ArchType Arch =  Triple(TT).getArch();
   for (iterator it = begin(), ie = end(); it != ie; ++it) {
     if (it->ArchMatchFn(Arch)) {
       if (Matching) {
         Error = std::string("Cannot choose between targets \"") +
           Matching->Name  + "\" and \"" + it->Name + "\"";
-        return 0;
+        return nullptr;
       }
       Matching = &*it;
     }
@@ -87,7 +87,7 @@ const Target *TargetRegistry::lookupTarget(const std::string &TT,
   if (!Matching) {
     Error = "No available targets are compatible with this triple, "
       "see -version for the available targets.";
-    return 0;
+    return nullptr;
   }
 
   return Matching;
@@ -121,7 +121,7 @@ const Target *TargetRegistry::getClosestTargetForJIT(std::string &Error) {
 
   if (TheTarget && !TheTarget->hasJIT()) {
     Error = "No JIT compatible target available for this host";
-    return 0;
+    return nullptr;
   }
 
   return TheTarget;
diff --git a/lib/Support/ThreadLocal.cpp b/lib/Support/ThreadLocal.cpp
index aebbcad25cd..2dec9eb417f 100644
--- a/lib/Support/ThreadLocal.cpp
+++ b/lib/Support/ThreadLocal.cpp
@@ -53,7 +53,7 @@ using namespace sys;
 ThreadLocalImpl::ThreadLocalImpl() : data() {
   static_assert(sizeof(pthread_key_t) <= sizeof(data), "size too big");
   pthread_key_t* key = reinterpret_cast<pthread_key_t*>(&data);
-  int errorcode = pthread_key_create(key, NULL);
+  int errorcode = pthread_key_create(key, nullptr);
   assert(errorcode == 0);
   (void) errorcode;
 }
@@ -78,7 +78,7 @@ const void* ThreadLocalImpl::getInstance() {
 }
 
 void ThreadLocalImpl::removeInstance() {
-  setInstance(0);
+  setInstance(nullptr);
 }
 
 }
diff --git a/lib/Support/Threading.cpp b/lib/Support/Threading.cpp
index 9d7ac6c18de..1acfa79b11d 100644
--- a/lib/Support/Threading.cpp
+++ b/lib/Support/Threading.cpp
@@ -21,7 +21,7 @@ using namespace llvm;
 
 static bool multithreaded_mode = false;
 
-static sys::Mutex* global_lock = 0;
+static sys::Mutex* global_lock = nullptr;
 
 bool llvm::llvm_start_multithreaded() {
 #if LLVM_ENABLE_THREADS != 0
@@ -73,7 +73,7 @@ struct ThreadInfo {
 static void *ExecuteOnThread_Dispatch(void *Arg) {
   ThreadInfo *TI = reinterpret_cast<ThreadInfo*>(Arg);
   TI->UserFn(TI->UserData);
-  return 0;
+  return nullptr;
 }
 
 void llvm::llvm_execute_on_thread(void (*Fn)(void*), void *UserData,
@@ -97,7 +97,7 @@ void llvm::llvm_execute_on_thread(void (*Fn)(void*), void *UserData,
     goto error;
 
   // Wait for the thread and clean up.
-  ::pthread_join(Thread, 0);
+  ::pthread_join(Thread, nullptr);
 
  error:
   ::pthread_attr_destroy(&Attr);
diff --git a/lib/Support/Timer.cpp b/lib/Support/Timer.cpp
index 7cf4d372a55..c2ce90c8588 100644
--- a/lib/Support/Timer.cpp
+++ b/lib/Support/Timer.cpp
@@ -77,7 +77,7 @@ raw_ostream *llvm::CreateInfoOutputFile() {
 }
 
 
-static TimerGroup *DefaultTimerGroup = 0;
+static TimerGroup *DefaultTimerGroup = nullptr;
 static TimerGroup *getDefaultTimerGroup() {
   TimerGroup *tmp = DefaultTimerGroup;
   sys::MemoryFence();
@@ -235,11 +235,11 @@ static Timer &getNamedRegionTimer(StringRef Name) {
 
 NamedRegionTimer::NamedRegionTimer(StringRef Name,
                                    bool Enabled)
-  : TimeRegion(!Enabled ? 0 : &getNamedRegionTimer(Name)) {}
+  : TimeRegion(!Enabled ? nullptr : &getNamedRegionTimer(Name)) {}
 
 NamedRegionTimer::NamedRegionTimer(StringRef Name, StringRef GroupName,
                                    bool Enabled)
-  : TimeRegion(!Enabled ? 0 : &NamedGroupedTimers->get(Name, GroupName)) {}
+  : TimeRegion(!Enabled ? nullptr : &NamedGroupedTimers->get(Name, GroupName)){}
 
 //===----------------------------------------------------------------------===//
 //   TimerGroup Implementation
@@ -247,10 +247,10 @@ NamedRegionTimer::NamedRegionTimer(StringRef Name, StringRef GroupName,
 
 /// TimerGroupList - This is the global list of TimerGroups, maintained by the
 /// TimerGroup ctor/dtor and is protected by the TimerLock lock.
-static TimerGroup *TimerGroupList = 0;
+static TimerGroup *TimerGroupList = nullptr;
 
 TimerGroup::TimerGroup(StringRef name)
-  : Name(name.begin(), name.end()), FirstTimer(0) {
+  : Name(name.begin(), name.end()), FirstTimer(nullptr) {
     
   // Add the group to TimerGroupList.
   sys::SmartScopedLock<true> L(*TimerLock);
@@ -264,7 +264,7 @@ TimerGroup::TimerGroup(StringRef name)
 TimerGroup::~TimerGroup() {
   // If the timer group is destroyed before the timers it owns, accumulate and
   // print the timing data.
-  while (FirstTimer != 0)
+  while (FirstTimer != nullptr)
     removeTimer(*FirstTimer);
   
   // Remove the group from the TimerGroupList.
@@ -282,7 +282,7 @@ void TimerGroup::removeTimer(Timer &T) {
   if (T.Started)
     TimersToPrint.push_back(std::make_pair(T.Time, T.Name));
 
-  T.TG = 0;
+  T.TG = nullptr;
   
   // Unlink the timer from our list.
   *T.Prev = T.Next;
@@ -291,7 +291,7 @@ void TimerGroup::removeTimer(Timer &T) {
   
   // Print the report when all timers in this group are destroyed if some of
   // them were started.
-  if (FirstTimer != 0 || TimersToPrint.empty())
+  if (FirstTimer != nullptr || TimersToPrint.empty())
     return;
   
   raw_ostream *OutStream = CreateInfoOutputFile();
diff --git a/lib/Support/Triple.cpp b/lib/Support/Triple.cpp
index 71abb9d1657..e65d02b52f4 100644
--- a/lib/Support/Triple.cpp
+++ b/lib/Support/Triple.cpp
@@ -57,7 +57,7 @@ const char *Triple::getArchTypeName(ArchType Kind) {
 const char *Triple::getArchTypePrefix(ArchType Kind) {
   switch (Kind) {
   default:
-    return 0;
+    return nullptr;
 
   case aarch64:
   case aarch64_be:  return "aarch64";
@@ -210,7 +210,7 @@ Triple::ArchType Triple::getArchTypeForLLVMName(StringRef Name) {
 // Returns architecture name that is understood by the target assembler.
 const char *Triple::getArchNameForAssembler() {
   if (!isOSDarwin() && getVendor() != Triple::Apple)
-    return NULL;
+    return nullptr;
 
   return StringSwitch<const char*>(getArchName())
     .Case("i386", "i386")
@@ -232,7 +232,7 @@ const char *Triple::getArchNameForAssembler() {
     .Case("amdil", "amdil")
     .Case("spir", "spir")
     .Case("spir64", "spir64")
-    .Default(NULL);
+    .Default(nullptr);
 }
 
 static Triple::ArchType parseArch(StringRef ArchName) {
diff --git a/lib/Support/YAMLParser.cpp b/lib/Support/YAMLParser.cpp
index 73ce5e009be..573bb47868f 100644
--- a/lib/Support/YAMLParser.cpp
+++ b/lib/Support/YAMLParser.cpp
@@ -1876,14 +1876,14 @@ Node *KeyValueNode::getValue() {
 void MappingNode::increment() {
   if (failed()) {
     IsAtEnd = true;
-    CurrentEntry = 0;
+    CurrentEntry = nullptr;
     return;
   }
   if (CurrentEntry) {
     CurrentEntry->skip();
     if (Type == MT_Inline) {
       IsAtEnd = true;
-      CurrentEntry = 0;
+      CurrentEntry = nullptr;
       return;
     }
   }
@@ -1896,13 +1896,13 @@ void MappingNode::increment() {
     case Token::TK_BlockEnd:
       getNext();
       IsAtEnd = true;
-      CurrentEntry = 0;
+      CurrentEntry = nullptr;
       break;
     default:
       setError("Unexpected token. Expected Key or Block End", T);
     case Token::TK_Error:
       IsAtEnd = true;
-      CurrentEntry = 0;
+      CurrentEntry = nullptr;
     }
   } else {
     switch (T.Kind) {
@@ -1915,14 +1915,14 @@ void MappingNode::increment() {
     case Token::TK_Error:
       // Set this to end iterator.
       IsAtEnd = true;
-      CurrentEntry = 0;
+      CurrentEntry = nullptr;
       break;
     default:
       setError( "Unexpected token. Expected Key, Flow Entry, or Flow "
                 "Mapping End."
               , T);
       IsAtEnd = true;
-      CurrentEntry = 0;
+      CurrentEntry = nullptr;
     }
   }
 }
@@ -1930,7 +1930,7 @@ void MappingNode::increment() {
 void SequenceNode::increment() {
   if (failed()) {
     IsAtEnd = true;
-    CurrentEntry = 0;
+    CurrentEntry = nullptr;
     return;
   }
   if (CurrentEntry)
@@ -1941,37 +1941,37 @@ void SequenceNode::increment() {
     case Token::TK_BlockEntry:
       getNext();
       CurrentEntry = parseBlockNode();
-      if (CurrentEntry == 0) { // An error occurred.
+      if (CurrentEntry == nullptr) { // An error occurred.
         IsAtEnd = true;
-        CurrentEntry = 0;
+        CurrentEntry = nullptr;
       }
       break;
     case Token::TK_BlockEnd:
       getNext();
       IsAtEnd = true;
-      CurrentEntry = 0;
+      CurrentEntry = nullptr;
       break;
     default:
       setError( "Unexpected token. Expected Block Entry or Block End."
               , T);
     case Token::TK_Error:
       IsAtEnd = true;
-      CurrentEntry = 0;
+      CurrentEntry = nullptr;
     }
   } else if (SeqType == ST_Indentless) {
     switch (T.Kind) {
     case Token::TK_BlockEntry:
       getNext();
       CurrentEntry = parseBlockNode();
-      if (CurrentEntry == 0) { // An error occurred.
+      if (CurrentEntry == nullptr) { // An error occurred.
         IsAtEnd = true;
-        CurrentEntry = 0;
+        CurrentEntry = nullptr;
       }
       break;
     default:
     case Token::TK_Error:
       IsAtEnd = true;
-      CurrentEntry = 0;
+      CurrentEntry = nullptr;
     }
   } else if (SeqType == ST_Flow) {
     switch (T.Kind) {
@@ -1985,7 +1985,7 @@ void SequenceNode::increment() {
     case Token::TK_Error:
       // Set this to end iterator.
       IsAtEnd = true;
-      CurrentEntry = 0;
+      CurrentEntry = nullptr;
       break;
     case Token::TK_StreamEnd:
     case Token::TK_DocumentEnd:
@@ -1993,13 +1993,13 @@ void SequenceNode::increment() {
       setError("Could not find closing ]!", T);
       // Set this to end iterator.
       IsAtEnd = true;
-      CurrentEntry = 0;
+      CurrentEntry = nullptr;
       break;
     default:
       if (!WasPreviousTokenFlowEntry) {
         setError("Expected , between entries!", T);
         IsAtEnd = true;
-        CurrentEntry = 0;
+        CurrentEntry = nullptr;
         break;
       }
       // Otherwise it must be a flow entry.
@@ -2013,7 +2013,7 @@ void SequenceNode::increment() {
   }
 }
 
-Document::Document(Stream &S) : stream(S), Root(0) {
+Document::Document(Stream &S) : stream(S), Root(nullptr) {
   // Tag maps starts with two default mappings.
   TagMap["!"] = "!";
   TagMap["!!"] = "tag:yaml.org,2002:";
@@ -2070,7 +2070,7 @@ parse_property:
   case Token::TK_Anchor:
     if (AnchorInfo.Kind == Token::TK_Anchor) {
       setError("Already encountered an anchor for this node!", T);
-      return 0;
+      return nullptr;
     }
     AnchorInfo = getNext(); // Consume TK_Anchor.
     T = peekNext();
@@ -2078,7 +2078,7 @@ parse_property:
   case Token::TK_Tag:
     if (TagInfo.Kind == Token::TK_Tag) {
       setError("Already encountered a tag for this node!", T);
-      return 0;
+      return nullptr;
     }
     TagInfo = getNext(); // Consume TK_Tag.
     T = peekNext();
@@ -2146,10 +2146,10 @@ parse_property:
     //       !!null null.
     return new (NodeAllocator) NullNode(stream.CurrentDoc);
   case Token::TK_Error:
-    return 0;
+    return nullptr;
   }
   llvm_unreachable("Control flow shouldn't reach here.");
-  return 0;
+  return nullptr;
 }
 
 bool Document::parseDirectives() {
diff --git a/lib/Support/YAMLTraits.cpp b/lib/Support/YAMLTraits.cpp
index 5472e0e1dd4..38f3ec7c7f9 100644
--- a/lib/Support/YAMLTraits.cpp
+++ b/lib/Support/YAMLTraits.cpp
@@ -47,7 +47,7 @@ Input::Input(StringRef InputContent,
              void *DiagHandlerCtxt)
   : IO(Ctxt),
     Strm(new Stream(InputContent, SrcMgr)),
-    CurrentNode(NULL) {
+    CurrentNode(nullptr) {
   if (DiagHandler)
     SrcMgr.setDiagHandler(DiagHandler, DiagHandlerCtxt);
   DocIterator = Strm->begin();
@@ -351,7 +351,7 @@ Input::HNode *Input::createHNodes(Node *N) {
     return new EmptyHNode(N);
   } else {
     setError(N, "unknown node kind");
-    return NULL;
+    return nullptr;
   }
 }