Index: include/clang/AST/Attr.h
===================================================================
--- include/clang/AST/Attr.h
+++ include/clang/AST/Attr.h
@@ -23,9 +23,9 @@
 #include "clang/Basic/OpenMPKinds.h"
 #include "clang/Basic/Sanitizers.h"
 #include "clang/Basic/SourceLocation.h"
-#include "clang/Basic/VersionTuple.h"
 #include "llvm/ADT/StringSwitch.h"
 #include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/VersionTuple.h"
 #include "llvm/Support/raw_ostream.h"
 #include <algorithm>
 #include <cassert>
Index: include/clang/AST/Availability.h
===================================================================
--- include/clang/AST/Availability.h
+++ include/clang/AST/Availability.h
@@ -15,8 +15,8 @@
 #define LLVM_CLANG_AST_AVAILABILITY_H
 
 #include "clang/Basic/SourceLocation.h"
-#include "clang/Basic/VersionTuple.h"
 #include "llvm/ADT/StringRef.h"
+#include "llvm/Support/VersionTuple.h"
 
 namespace clang {
 
Index: include/clang/AST/DeclBase.h
===================================================================
--- include/clang/AST/DeclBase.h
+++ include/clang/AST/DeclBase.h
@@ -19,7 +19,6 @@
 #include "clang/Basic/LLVM.h"
 #include "clang/Basic/SourceLocation.h"
 #include "clang/Basic/Specifiers.h"
-#include "clang/Basic/VersionTuple.h"
 #include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/PointerIntPair.h"
 #include "llvm/ADT/PointerUnion.h"
@@ -28,6 +27,7 @@
 #include "llvm/Support/Casting.h"
 #include "llvm/Support/Compiler.h"
 #include "llvm/Support/PrettyStackTrace.h"
+#include "llvm/Support/VersionTuple.h"
 #include <algorithm>
 #include <cassert>
 #include <cstddef>
Index: include/clang/AST/ExprObjC.h
===================================================================
--- include/clang/AST/ExprObjC.h
+++ include/clang/AST/ExprObjC.h
@@ -25,7 +25,6 @@
 #include "clang/Basic/LLVM.h"
 #include "clang/Basic/SourceLocation.h"
 #include "clang/Basic/Specifiers.h"
-#include "clang/Basic/VersionTuple.h"
 #include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/None.h"
 #include "llvm/ADT/Optional.h"
@@ -36,6 +35,7 @@
 #include "llvm/Support/Casting.h"
 #include "llvm/Support/Compiler.h"
 #include "llvm/Support/TrailingObjects.h"
+#include "llvm/Support/VersionTuple.h"
 #include "llvm/Support/type_traits.h"
 #include <cassert>
 #include <cstddef>
Index: include/clang/Basic/AlignedAllocation.h
===================================================================
--- include/clang/Basic/AlignedAllocation.h
+++ include/clang/Basic/AlignedAllocation.h
@@ -16,9 +16,9 @@
 #ifndef LLVM_CLANG_BASIC_ALIGNED_ALLOCATION_H
 #define LLVM_CLANG_BASIC_ALIGNED_ALLOCATION_H
 
-#include "clang/Basic/VersionTuple.h"
 #include "llvm/ADT/Triple.h"
 #include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/VersionTuple.h"
 
 namespace clang {
 
Index: include/clang/Basic/LLVM.h
===================================================================
--- include/clang/Basic/LLVM.h
+++ include/clang/Basic/LLVM.h
@@ -28,6 +28,7 @@
   // ADT's.
   class StringRef;
   class Twine;
+  class VersionTuple;
   template<typename T> class ArrayRef;
   template<typename T> class MutableArrayRef;
   template<typename T> class OwningArrayRef;
@@ -60,17 +61,18 @@
   using llvm::cast_or_null;
   
   // ADT's.
-  using llvm::None;
-  using llvm::Optional;
-  using llvm::StringRef;
-  using llvm::Twine;
   using llvm::ArrayRef;
   using llvm::MutableArrayRef;
+  using llvm::None;
+  using llvm::Optional;
   using llvm::OwningArrayRef;
+  using llvm::SaveAndRestore;
   using llvm::SmallString;
   using llvm::SmallVector;
   using llvm::SmallVectorImpl;
-  using llvm::SaveAndRestore;
+  using llvm::StringRef;
+  using llvm::Twine;
+  using llvm::VersionTuple;
 
   // Error handling.
   using llvm::Expected;
Index: include/clang/Basic/ObjCRuntime.h
===================================================================
--- include/clang/Basic/ObjCRuntime.h
+++ include/clang/Basic/ObjCRuntime.h
@@ -16,10 +16,10 @@
 #define LLVM_CLANG_BASIC_OBJCRUNTIME_H
 
 #include "clang/Basic/LLVM.h"
-#include "clang/Basic/VersionTuple.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/Triple.h"
 #include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/VersionTuple.h"
 #include <string>
 
 namespace clang {
Index: include/clang/Basic/TargetInfo.h
===================================================================
--- include/clang/Basic/TargetInfo.h
+++ include/clang/Basic/TargetInfo.h
@@ -20,7 +20,6 @@
 #include "clang/Basic/Specifiers.h"
 #include "clang/Basic/TargetCXXABI.h"
 #include "clang/Basic/TargetOptions.h"
-#include "clang/Basic/VersionTuple.h"
 #include "llvm/ADT/APInt.h"
 #include "llvm/ADT/IntrusiveRefCntPtr.h"
 #include "llvm/ADT/Optional.h"
@@ -30,6 +29,7 @@
 #include "llvm/ADT/Triple.h"
 #include "llvm/IR/DataLayout.h"
 #include "llvm/Support/DataTypes.h"
+#include "llvm/Support/VersionTuple.h"
 #include <cassert>
 #include <string>
 #include <vector>
Index: include/clang/Basic/VersionTuple.h
===================================================================
--- include/clang/Basic/VersionTuple.h
+++ /dev/null
@@ -1,153 +0,0 @@
-//===- VersionTuple.h - Version Number Handling -----------------*- C++ -*-===//
-//
-//                     The LLVM Compiler Infrastructure
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-///
-/// \file
-/// Defines the clang::VersionTuple class, which represents a version in
-/// the form major[.minor[.subminor]].
-///
-//===----------------------------------------------------------------------===//
-#ifndef LLVM_CLANG_BASIC_VERSIONTUPLE_H
-#define LLVM_CLANG_BASIC_VERSIONTUPLE_H
-
-#include "clang/Basic/LLVM.h"
-#include "llvm/ADT/Optional.h"
-#include <string>
-#include <tuple>
-
-namespace clang {
-
-/// Represents a version number in the form major[.minor[.subminor[.build]]].
-class VersionTuple {
-  unsigned Major : 32;
-
-  unsigned Minor : 31;
-  unsigned HasMinor : 1;
-
-  unsigned Subminor : 31;
-  unsigned HasSubminor : 1;
-
-  unsigned Build : 31;
-  unsigned HasBuild : 1;
-
-public:
-  VersionTuple()
-      : Major(0), Minor(0), HasMinor(false), Subminor(0), HasSubminor(false),
-        Build(0), HasBuild(false) {}
-
-  explicit VersionTuple(unsigned Major)
-      : Major(Major), Minor(0), HasMinor(false), Subminor(0),
-        HasSubminor(false), Build(0), HasBuild(false) {}
-
-  explicit VersionTuple(unsigned Major, unsigned Minor)
-      : Major(Major), Minor(Minor), HasMinor(true), Subminor(0),
-        HasSubminor(false), Build(0), HasBuild(false) {}
-
-  explicit VersionTuple(unsigned Major, unsigned Minor, unsigned Subminor)
-      : Major(Major), Minor(Minor), HasMinor(true), Subminor(Subminor),
-        HasSubminor(true), Build(0), HasBuild(false) {}
-
-  explicit VersionTuple(unsigned Major, unsigned Minor, unsigned Subminor,
-                        unsigned Build)
-      : Major(Major), Minor(Minor), HasMinor(true), Subminor(Subminor),
-        HasSubminor(true), Build(Build), HasBuild(true) {}
-
-  /// Determine whether this version information is empty
-  /// (e.g., all version components are zero).
-  bool empty() const {
-    return Major == 0 && Minor == 0 && Subminor == 0 && Build == 0;
-  }
-
-  /// Retrieve the major version number.
-  unsigned getMajor() const { return Major; }
-
-  /// Retrieve the minor version number, if provided.
-  Optional<unsigned> getMinor() const {
-    if (!HasMinor)
-      return None;
-    return Minor;
-  }
-
-  /// Retrieve the subminor version number, if provided.
-  Optional<unsigned> getSubminor() const {
-    if (!HasSubminor)
-      return None;
-    return Subminor;
-  }
-
-  /// Retrieve the build version number, if provided.
-  Optional<unsigned> getBuild() const {
-    if (!HasBuild)
-      return None;
-    return Build;
-  }
-  
-  /// Determine if two version numbers are equivalent. If not
-  /// provided, minor and subminor version numbers are considered to be zero.
-  friend bool operator==(const VersionTuple& X, const VersionTuple &Y) {
-    return X.Major == Y.Major && X.Minor == Y.Minor &&
-           X.Subminor == Y.Subminor && X.Build == Y.Build;
-  }
-
-  /// Determine if two version numbers are not equivalent.
-  ///
-  /// If not provided, minor and subminor version numbers are considered to be 
-  /// zero.
-  friend bool operator!=(const VersionTuple &X, const VersionTuple &Y) {
-    return !(X == Y);
-  }
-
-  /// Determine whether one version number precedes another.
-  ///
-  /// If not provided, minor and subminor version numbers are considered to be
-  /// zero.
-  friend bool operator<(const VersionTuple &X, const VersionTuple &Y) {
-    return std::tie(X.Major, X.Minor, X.Subminor, X.Build) <
-           std::tie(Y.Major, Y.Minor, Y.Subminor, Y.Build);
-  }
-
-  /// Determine whether one version number follows another.
-  ///
-  /// If not provided, minor and subminor version numbers are considered to be
-  /// zero.
-  friend bool operator>(const VersionTuple &X, const VersionTuple &Y) {
-    return Y < X;
-  }
-
-  /// Determine whether one version number precedes or is
-  /// equivalent to another. 
-  ///
-  /// If not provided, minor and subminor version numbers are considered to be
-  /// zero.
-  friend bool operator<=(const VersionTuple &X, const VersionTuple &Y) {
-    return !(Y < X);
-  }
-
-  /// Determine whether one version number follows or is
-  /// equivalent to another.
-  ///
-  /// If not provided, minor and subminor version numbers are considered to be
-  /// zero.
-  friend bool operator>=(const VersionTuple &X, const VersionTuple &Y) {
-    return !(X < Y);
-  }
-
-  /// Retrieve a string representation of the version number.
-  std::string getAsString() const;
-
-  /// Try to parse the given string as a version number.
-  /// \returns \c true if the string does not match the regular expression
-  ///   [0-9]+(\.[0-9]+){0,3}
-  bool tryParse(StringRef string);
-};
-
-/// Print a version number.
-raw_ostream& operator<<(raw_ostream &Out, const VersionTuple &V);
-
-} // end namespace clang
-#endif // LLVM_CLANG_BASIC_VERSIONTUPLE_H
Index: include/clang/Driver/ToolChain.h
===================================================================
--- include/clang/Driver/ToolChain.h
+++ include/clang/Driver/ToolChain.h
@@ -12,7 +12,6 @@
 
 #include "clang/Basic/LLVM.h"
 #include "clang/Basic/Sanitizers.h"
-#include "clang/Basic/VersionTuple.h"
 #include "clang/Driver/Action.h"
 #include "clang/Driver/Multilib.h"
 #include "clang/Driver/Types.h"
@@ -22,6 +21,7 @@
 #include "llvm/ADT/Triple.h"
 #include "llvm/MC/MCTargetOptions.h"
 #include "llvm/Option/Option.h"
+#include "llvm/Support/VersionTuple.h"
 #include "llvm/Target/TargetOptions.h"
 #include <cassert>
 #include <memory>
Index: include/clang/Parse/Parser.h
===================================================================
--- include/clang/Parse/Parser.h
+++ include/clang/Parse/Parser.h
@@ -45,7 +45,6 @@
   class ColonProtectionRAIIObject;
   class InMessageExpressionRAIIObject;
   class PoisonSEHIdentifiersRAIIObject;
-  class VersionTuple;
   class OMPClause;
   class ObjCTypeParamList;
   class ObjCTypeParameter;
Index: include/clang/Sema/AttributeList.h
===================================================================
--- include/clang/Sema/AttributeList.h
+++ include/clang/Sema/AttributeList.h
@@ -18,11 +18,11 @@
 #include "clang/Basic/AttrSubjectMatchRules.h"
 #include "clang/Basic/SourceLocation.h"
 #include "clang/Basic/TargetInfo.h"
-#include "clang/Basic/VersionTuple.h"
 #include "clang/Sema/Ownership.h"
 #include "llvm/ADT/PointerUnion.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/Support/Allocator.h"
+#include "llvm/Support/VersionTuple.h"
 #include <cassert>
 #include <cstddef>
 #include <cstring>
Index: include/clang/Serialization/ASTReader.h
===================================================================
--- include/clang/Serialization/ASTReader.h
+++ include/clang/Serialization/ASTReader.h
@@ -28,7 +28,6 @@
 #include "clang/Basic/OpenCLOptions.h"
 #include "clang/Basic/SourceLocation.h"
 #include "clang/Basic/Version.h"
-#include "clang/Basic/VersionTuple.h"
 #include "clang/Lex/ExternalPreprocessorSource.h"
 #include "clang/Lex/HeaderSearch.h"
 #include "clang/Lex/PreprocessingRecord.h"
@@ -62,6 +61,7 @@
 #include "llvm/Support/Endian.h"
 #include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/Timer.h"
+#include "llvm/Support/VersionTuple.h"
 #include <cassert>
 #include <cstddef>
 #include <cstdint>
Index: include/clang/Serialization/ASTWriter.h
===================================================================
--- include/clang/Serialization/ASTWriter.h
+++ include/clang/Serialization/ASTWriter.h
@@ -93,7 +93,6 @@
 class TemplateParameterList;
 class Token;
 class TypeSourceInfo;
-class VersionTuple;
 
 /// Writes an AST file containing the contents of a translation unit.
 ///
Index: lib/AST/DeclBase.cpp
===================================================================
--- lib/AST/DeclBase.cpp
+++ lib/AST/DeclBase.cpp
@@ -34,7 +34,6 @@
 #include "clang/Basic/PartialDiagnostic.h"
 #include "clang/Basic/SourceLocation.h"
 #include "clang/Basic/TargetInfo.h"
-#include "clang/Basic/VersionTuple.h"
 #include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/PointerIntPair.h"
 #include "llvm/ADT/SmallVector.h"
@@ -42,6 +41,7 @@
 #include "llvm/Support/Casting.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/MathExtras.h"
+#include "llvm/Support/VersionTuple.h"
 #include "llvm/Support/raw_ostream.h"
 #include <algorithm>
 #include <cassert>
Index: lib/Basic/CMakeLists.txt
===================================================================
--- lib/Basic/CMakeLists.txt
+++ lib/Basic/CMakeLists.txt
@@ -93,7 +93,6 @@
   Targets/XCore.cpp
   TokenKinds.cpp
   Version.cpp
-  VersionTuple.cpp
   VirtualFileSystem.cpp
   Warnings.cpp
   XRayInstr.cpp
Index: lib/Basic/ObjCRuntime.cpp
===================================================================
--- lib/Basic/ObjCRuntime.cpp
+++ lib/Basic/ObjCRuntime.cpp
@@ -13,8 +13,8 @@
 //===----------------------------------------------------------------------===//
 
 #include "clang/Basic/ObjCRuntime.h"
-#include "clang/Basic/VersionTuple.h"
 #include "llvm/ADT/StringRef.h"
+#include "llvm/Support/VersionTuple.h"
 #include "llvm/Support/raw_ostream.h"
 #include <cstddef>
 #include <string>
Index: lib/Basic/VersionTuple.cpp
===================================================================
--- lib/Basic/VersionTuple.cpp
+++ /dev/null
@@ -1,100 +0,0 @@
-//===- VersionTuple.cpp - Version Number Handling ---------------*- C++ -*-===//
-//
-//                     The LLVM Compiler Infrastructure
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-//
-// This file implements the VersionTuple class, which represents a version in
-// the form major[.minor[.subminor]].
-//
-//===----------------------------------------------------------------------===//
-#include "clang/Basic/VersionTuple.h"
-#include "llvm/Support/raw_ostream.h"
-
-using namespace clang;
-
-std::string VersionTuple::getAsString() const {
-  std::string Result;
-  {
-    llvm::raw_string_ostream Out(Result);
-    Out << *this;
-  }
-  return Result;
-}
-
-raw_ostream& clang::operator<<(raw_ostream &Out, 
-                                     const VersionTuple &V) {
-  Out << V.getMajor();
-  if (Optional<unsigned> Minor = V.getMinor())
-    Out << '.' << *Minor;
-  if (Optional<unsigned> Subminor = V.getSubminor())
-    Out << '.' << *Subminor;
-  if (Optional<unsigned> Build = V.getBuild())
-    Out << '.' << *Build;
-  return Out;
-}
-
-static bool parseInt(StringRef &input, unsigned &value) {
-  assert(value == 0);
-  if (input.empty()) return true;
-
-  char next = input[0];
-  input = input.substr(1);
-  if (next < '0' || next > '9') return true;
-  value = (unsigned) (next - '0');
-
-  while (!input.empty()) {
-    next = input[0];
-    if (next < '0' || next > '9') return false;
-    input = input.substr(1);
-    value = value * 10 + (unsigned) (next - '0');
-  }
-
-  return false;
-}
-
-bool VersionTuple::tryParse(StringRef input) {
-  unsigned major = 0, minor = 0, micro = 0, build = 0;
-
-  // Parse the major version, [0-9]+
-  if (parseInt(input, major)) return true;
-
-  if (input.empty()) {
-    *this = VersionTuple(major);
-    return false;
-  }
-
-  // If we're not done, parse the minor version, \.[0-9]+
-  if (input[0] != '.') return true;
-  input = input.substr(1);
-  if (parseInt(input, minor)) return true;
-
-  if (input.empty()) {
-    *this = VersionTuple(major, minor);
-    return false;
-  }
-
-  // If we're not done, parse the micro version, \.[0-9]+
-  if (input[0] != '.') return true;
-  input = input.substr(1);
-  if (parseInt(input, micro)) return true;
-
-  if (input.empty()) {
-    *this = VersionTuple(major, minor, micro);
-    return false;
-  }
-
-  // If we're not done, parse the micro version, \.[0-9]+
-  if (input[0] != '.') return true;
-  input = input.substr(1);
-  if (parseInt(input, build)) return true;
-
-  // If we have characters left over, it's an error.
-  if (!input.empty()) return true;
-
-  *this = VersionTuple(major, minor, micro, build);
-  return false;
-}
Index: lib/Driver/ToolChain.cpp
===================================================================
--- lib/Driver/ToolChain.cpp
+++ lib/Driver/ToolChain.cpp
@@ -13,7 +13,6 @@
 #include "ToolChains/Clang.h"
 #include "clang/Basic/ObjCRuntime.h"
 #include "clang/Basic/Sanitizers.h"
-#include "clang/Basic/VersionTuple.h"
 #include "clang/Basic/VirtualFileSystem.h"
 #include "clang/Config/config.h"
 #include "clang/Driver/Action.h"
@@ -29,6 +28,7 @@
 #include "llvm/ADT/Triple.h"
 #include "llvm/ADT/Twine.h"
 #include "llvm/Config/llvm-config.h"
+#include "llvm/MC/MCTargetOptions.h"
 #include "llvm/Option/Arg.h"
 #include "llvm/Option/ArgList.h"
 #include "llvm/Option/OptTable.h"
@@ -36,9 +36,9 @@
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/Path.h"
-#include "llvm/MC/MCTargetOptions.h"
 #include "llvm/Support/TargetParser.h"
 #include "llvm/Support/TargetRegistry.h"
+#include "llvm/Support/VersionTuple.h"
 #include <cassert>
 #include <cstddef>
 #include <cstring>
Index: lib/Driver/ToolChains/Cuda.h
===================================================================
--- lib/Driver/ToolChains/Cuda.h
+++ lib/Driver/ToolChains/Cuda.h
@@ -11,14 +11,14 @@
 #define LLVM_CLANG_LIB_DRIVER_TOOLCHAINS_CUDA_H
 
 #include "clang/Basic/Cuda.h"
-#include "clang/Basic/VersionTuple.h"
 #include "clang/Driver/Action.h"
 #include "clang/Driver/Multilib.h"
-#include "clang/Driver/ToolChain.h"
 #include "clang/Driver/Tool.h"
+#include "clang/Driver/ToolChain.h"
 #include "llvm/ADT/Optional.h"
 #include "llvm/ADT/SmallSet.h"
 #include "llvm/Support/Compiler.h"
+#include "llvm/Support/VersionTuple.h"
 #include <set>
 #include <vector>
 
Index: lib/Frontend/CompilerInvocation.cpp
===================================================================
--- lib/Frontend/CompilerInvocation.cpp
+++ lib/Frontend/CompilerInvocation.cpp
@@ -23,7 +23,6 @@
 #include "clang/Basic/SourceLocation.h"
 #include "clang/Basic/TargetOptions.h"
 #include "clang/Basic/Version.h"
-#include "clang/Basic/VersionTuple.h"
 #include "clang/Basic/VirtualFileSystem.h"
 #include "clang/Basic/Visibility.h"
 #include "clang/Basic/XRayInstr.h"
@@ -76,6 +75,7 @@
 #include "llvm/Support/Path.h"
 #include "llvm/Support/Process.h"
 #include "llvm/Support/Regex.h"
+#include "llvm/Support/VersionTuple.h"
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/Target/TargetOptions.h"
 #include <algorithm>
Index: lib/Serialization/ASTReader.cpp
===================================================================
--- lib/Serialization/ASTReader.cpp
+++ lib/Serialization/ASTReader.cpp
@@ -61,7 +61,6 @@
 #include "clang/Basic/TargetOptions.h"
 #include "clang/Basic/TokenKinds.h"
 #include "clang/Basic/Version.h"
-#include "clang/Basic/VersionTuple.h"
 #include "clang/Frontend/PCHContainerOperations.h"
 #include "clang/Lex/HeaderSearch.h"
 #include "clang/Lex/HeaderSearchOptions.h"
@@ -104,8 +103,8 @@
 #include "llvm/ADT/iterator_range.h"
 #include "llvm/Bitcode/BitstreamReader.h"
 #include "llvm/Support/Casting.h"
-#include "llvm/Support/Compression.h"
 #include "llvm/Support/Compiler.h"
+#include "llvm/Support/Compression.h"
 #include "llvm/Support/DJB.h"
 #include "llvm/Support/Endian.h"
 #include "llvm/Support/Error.h"
@@ -115,6 +114,7 @@
 #include "llvm/Support/Path.h"
 #include "llvm/Support/SaveAndRestore.h"
 #include "llvm/Support/Timer.h"
+#include "llvm/Support/VersionTuple.h"
 #include "llvm/Support/raw_ostream.h"
 #include <algorithm>
 #include <cassert>
Index: lib/Serialization/ASTWriter.cpp
===================================================================
--- lib/Serialization/ASTWriter.cpp
+++ lib/Serialization/ASTWriter.cpp
@@ -53,7 +53,6 @@
 #include "clang/Basic/TargetInfo.h"
 #include "clang/Basic/TargetOptions.h"
 #include "clang/Basic/Version.h"
-#include "clang/Basic/VersionTuple.h"
 #include "clang/Lex/HeaderSearch.h"
 #include "clang/Lex/HeaderSearchOptions.h"
 #include "clang/Lex/MacroInfo.h"
@@ -97,6 +96,7 @@
 #include "llvm/Support/OnDiskHashTable.h"
 #include "llvm/Support/Path.h"
 #include "llvm/Support/SHA1.h"
+#include "llvm/Support/VersionTuple.h"
 #include "llvm/Support/raw_ostream.h"
 #include <algorithm>
 #include <cassert>