Index: clang-tools-extra/clangd/CMakeLists.txt
===================================================================
--- clang-tools-extra/clangd/CMakeLists.txt
+++ clang-tools-extra/clangd/CMakeLists.txt
@@ -38,17 +38,16 @@
   XRefs.cpp
 
   index/CanonicalIncludes.cpp
+  index/Dex.cpp
   index/FileIndex.cpp
   index/Index.cpp
+  index/Iterator.cpp
   index/MemIndex.cpp
   index/Merge.cpp
   index/Serialization.cpp
   index/SymbolCollector.cpp
   index/SymbolYAML.cpp
-
-  index/dex/DexIndex.cpp
-  index/dex/Iterator.cpp
-  index/dex/Trigram.cpp
+  index/Trigram.cpp
 
   LINK_LIBS
   clangAST
Index: clang-tools-extra/clangd/index/Dex.h
===================================================================
--- clang-tools-extra/clangd/index/Dex.h
+++ clang-tools-extra/clangd/index/Dex.h
@@ -1,4 +1,4 @@
-//===--- DexIndex.h - Dex Symbol Index Implementation -----------*- C++ -*-===//
+//===--- Dex.h - Efficient Symbol Index Implementation ----------*- C++ -*-===//
 //
 //                     The LLVM Compiler Infrastructure
 //
@@ -17,19 +17,18 @@
 //
 //===----------------------------------------------------------------------===//
 
-#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANGD_INDEX_DEX_DEXINDEX_H
-#define LLVM_CLANG_TOOLS_EXTRA_CLANGD_INDEX_DEX_DEXINDEX_H
+#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANGD_INDEX_DEXINDEX_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANGD_INDEX_DEXINDEX_H
 
-#include "../Index.h"
-#include "../MemIndex.h"
-#include "../SymbolCollector.h"
+#include "Index.h"
 #include "Iterator.h"
+#include "MemIndex.h"
+#include "SymbolCollector.h"
 #include "Token.h"
 #include "Trigram.h"
 
 namespace clang {
 namespace clangd {
-namespace dex {
 
 /// In-memory Dex trigram-based index implementation.
 // FIXME(kbobyrev): Introduce serialization and deserialization of the symbol
@@ -106,8 +105,7 @@
 /// This function is exposed for testing only.
 std::vector<std::string> generateProximityURIs(llvm::StringRef URIPath);
 
-} // namespace dex
 } // namespace clangd
 } // namespace clang
 
-#endif // LLVM_CLANG_TOOLS_EXTRA_CLANGD_INDEX_DEX_DEXINDEX_H
+#endif // LLVM_CLANG_TOOLS_EXTRA_CLANGD_INDEX_DEXINDEX_H
Index: clang-tools-extra/clangd/index/Dex.cpp
===================================================================
--- clang-tools-extra/clangd/index/Dex.cpp
+++ clang-tools-extra/clangd/index/Dex.cpp
@@ -1,4 +1,4 @@
-//===--- DexIndex.cpp - Dex Symbol Index Implementation ---------*- C++ -*-===//
+//===--- Dex.cpp - Efficient Symbol Index Implementation --------*- C++ -*-===//
 //
 //                     The LLVM Compiler Infrastructure
 //
@@ -7,18 +7,17 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "DexIndex.h"
-#include "../../FileDistance.h"
-#include "../../FuzzyMatch.h"
-#include "../../Logger.h"
-#include "../../Quality.h"
+#include "Dex.h"
+#include "../FileDistance.h"
+#include "../FuzzyMatch.h"
+#include "../Logger.h"
+#include "../Quality.h"
 #include "llvm/ADT/StringSet.h"
 #include <algorithm>
 #include <queue>
 
 namespace clang {
 namespace clangd {
-namespace dex {
 
 namespace {
 
@@ -266,6 +265,5 @@
   return Result;
 }
 
-} // namespace dex
 } // namespace clangd
 } // namespace clang
Index: clang-tools-extra/clangd/index/Iterator.h
===================================================================
--- clang-tools-extra/clangd/index/Iterator.h
+++ clang-tools-extra/clangd/index/Iterator.h
@@ -28,8 +28,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANGD_INDEX_DEX_ITERATOR_H
-#define LLVM_CLANG_TOOLS_EXTRA_CLANGD_INDEX_DEX_ITERATOR_H
+#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANGD_INDEX_ITERATOR_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANGD_INDEX_ITERATOR_H
 
 #include "llvm/ADT/ArrayRef.h"
 #include "llvm/Support/raw_ostream.h"
@@ -39,7 +39,6 @@
 
 namespace clang {
 namespace clangd {
-namespace dex {
 
 /// Symbol position in the list of all index symbols sorted by a pre-computed
 /// symbol quality.
@@ -200,7 +199,6 @@
   Children.push_back(move(Head));
 }
 
-} // namespace dex
 } // namespace clangd
 } // namespace clang
 
Index: clang-tools-extra/clangd/index/Iterator.cpp
===================================================================
--- clang-tools-extra/clangd/index/Iterator.cpp
+++ clang-tools-extra/clangd/index/Iterator.cpp
@@ -14,7 +14,6 @@
 
 namespace clang {
 namespace clangd {
-namespace dex {
 
 namespace {
 
@@ -424,6 +423,5 @@
   return llvm::make_unique<LimitIterator>(move(Child), Limit);
 }
 
-} // namespace dex
 } // namespace clangd
 } // namespace clang
Index: clang-tools-extra/clangd/index/SymbolYAML.cpp
===================================================================
--- clang-tools-extra/clangd/index/SymbolYAML.cpp
+++ clang-tools-extra/clangd/index/SymbolYAML.cpp
@@ -11,7 +11,7 @@
 #include "../Trace.h"
 #include "Index.h"
 #include "Serialization.h"
-#include "dex/DexIndex.h"
+#include "Dex.h"
 #include "llvm/ADT/Optional.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/Support/Errc.h"
@@ -225,7 +225,7 @@
   if (!Slab)
     return nullptr;
   trace::Span Tracer("BuildIndex");
-  return UseDex ? dex::DexIndex::build(std::move(*Slab), URISchemes)
+  return UseDex ? DexIndex::build(std::move(*Slab), URISchemes)
                 : MemIndex::build(std::move(*Slab), RefSlab());
 }
 
Index: clang-tools-extra/clangd/index/Token.h
===================================================================
--- clang-tools-extra/clangd/index/Token.h
+++ clang-tools-extra/clangd/index/Token.h
@@ -19,10 +19,10 @@
 //
 //===----------------------------------------------------------------------===//
 
-#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANGD_DEX_TOKEN_H
-#define LLVM_CLANG_TOOLS_EXTRA_CLANGD_DEX_TOKEN_H
+#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANGD_TOKEN_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANGD_TOKEN_H
 
-#include "../Index.h"
+#include "Index.h"
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/Support/raw_ostream.h"
 #include <string>
@@ -30,7 +30,6 @@
 
 namespace clang {
 namespace clangd {
-namespace dex {
 
 /// A Token represents an attribute of a symbol, such as a particular trigram
 /// present in the name (used for fuzzy search).
@@ -90,32 +89,31 @@
   }
 };
 
-} // namespace dex
 } // namespace clangd
 } // namespace clang
 
 namespace llvm {
 
 // Support Tokens as DenseMap keys.
-template <> struct DenseMapInfo<clang::clangd::dex::Token> {
-  static inline clang::clangd::dex::Token getEmptyKey() {
-    return {clang::clangd::dex::Token::Kind::Sentinel, "EmptyKey"};
+template <> struct DenseMapInfo<clang::clangd::Token> {
+  static inline clang::clangd::Token getEmptyKey() {
+    return {clang::clangd::Token::Kind::Sentinel, "EmptyKey"};
   }
 
-  static inline clang::clangd::dex::Token getTombstoneKey() {
-    return {clang::clangd::dex::Token::Kind::Sentinel, "TombstoneKey"};
+  static inline clang::clangd::Token getTombstoneKey() {
+    return {clang::clangd::Token::Kind::Sentinel, "TombstoneKey"};
   }
 
-  static unsigned getHashValue(const clang::clangd::dex::Token &Tag) {
+  static unsigned getHashValue(const clang::clangd::Token &Tag) {
     return hash_value(Tag);
   }
 
-  static bool isEqual(const clang::clangd::dex::Token &LHS,
-                      const clang::clangd::dex::Token &RHS) {
+  static bool isEqual(const clang::clangd::Token &LHS,
+                      const clang::clangd::Token &RHS) {
     return LHS == RHS;
   }
 };
 
 } // namespace llvm
 
-#endif // LLVM_CLANG_TOOLS_EXTRA_CLANGD_DEX_TOKEN_H
+#endif // LLVM_CLANG_TOOLS_EXTRA_CLANGD_TOKEN_H
Index: clang-tools-extra/clangd/index/Trigram.h
===================================================================
--- clang-tools-extra/clangd/index/Trigram.h
+++ clang-tools-extra/clangd/index/Trigram.h
@@ -29,7 +29,6 @@
 
 namespace clang {
 namespace clangd {
-namespace dex {
 
 /// Returns list of unique fuzzy-search trigrams from unqualified symbol.
 ///
@@ -65,7 +64,6 @@
 /// characters (up to 3) to perform prefix match.
 std::vector<Token> generateQueryTrigrams(llvm::StringRef Query);
 
-} // namespace dex
 } // namespace clangd
 } // namespace clang
 
Index: clang-tools-extra/clangd/index/Trigram.cpp
===================================================================
--- clang-tools-extra/clangd/index/Trigram.cpp
+++ clang-tools-extra/clangd/index/Trigram.cpp
@@ -8,7 +8,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "Trigram.h"
-#include "../../FuzzyMatch.h"
+#include "../FuzzyMatch.h"
 #include "Token.h"
 #include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/DenseSet.h"
@@ -21,7 +21,6 @@
 
 namespace clang {
 namespace clangd {
-namespace dex {
 
 /// This is used to mark unigrams and bigrams and distinct them from complete
 /// trigrams. Since '$' is not present in valid identifier names, it is safe to
@@ -154,6 +153,5 @@
   return Result;
 }
 
-} // namespace dex
 } // namespace clangd
 } // namespace clang
Index: clang-tools-extra/clangd/tool/ClangdMain.cpp
===================================================================
--- clang-tools-extra/clangd/tool/ClangdMain.cpp
+++ clang-tools-extra/clangd/tool/ClangdMain.cpp
@@ -13,7 +13,6 @@
 #include "RIFF.h"
 #include "Trace.h"
 #include "index/SymbolYAML.h"
-#include "index/dex/DexIndex.h"
 #include "clang/Basic/Version.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/FileSystem.h"
Index: clang-tools-extra/unittests/clangd/DexIndexTests.cpp
===================================================================
--- clang-tools-extra/unittests/clangd/DexIndexTests.cpp
+++ clang-tools-extra/unittests/clangd/DexIndexTests.cpp
@@ -10,12 +10,12 @@
 #include "FuzzyMatch.h"
 #include "TestFS.h"
 #include "TestIndex.h"
+#include "index/Dex.h"
 #include "index/Index.h"
+#include "index/Iterator.h"
 #include "index/Merge.h"
-#include "index/dex/DexIndex.h"
-#include "index/dex/Iterator.h"
-#include "index/dex/Token.h"
-#include "index/dex/Trigram.h"
+#include "index/Token.h"
+#include "index/Trigram.h"
 #include "llvm/Support/ScopedPrinter.h"
 #include "llvm/Support/raw_ostream.h"
 #include "gmock/gmock.h"
@@ -29,7 +29,6 @@
 
 namespace clang {
 namespace clangd {
-namespace dex {
 namespace {
 
 std::vector<std::string> URISchemes = {"unittest"};
@@ -610,6 +609,5 @@
 }
 
 } // namespace
-} // namespace dex
 } // namespace clangd
 } // namespace clang
Index: clang-tools-extra/unittests/clangd/TestIndex.h
===================================================================
--- clang-tools-extra/unittests/clangd/TestIndex.h
+++ clang-tools-extra/unittests/clangd/TestIndex.h
@@ -1,4 +1,4 @@
-//===-- IndexHelpers.h ------------------------------------------*- C++ -*-===//
+//===-- TestIndex.h ---------------------------------------------*- C++ -*-===//
 //
 //                     The LLVM Compiler Infrastructure
 //
@@ -12,10 +12,6 @@
 
 #include "index/Index.h"
 #include "index/Merge.h"
-#include "index/dex/DexIndex.h"
-#include "index/dex/Iterator.h"
-#include "index/dex/Token.h"
-#include "index/dex/Trigram.h"
 
 namespace clang {
 namespace clangd {
Index: clang-tools-extra/unittests/clangd/TestIndex.cpp
===================================================================
--- clang-tools-extra/unittests/clangd/TestIndex.cpp
+++ clang-tools-extra/unittests/clangd/TestIndex.cpp
@@ -1,4 +1,4 @@
-//===-- IndexHelpers.cpp ----------------------------------------*- C++ -*-===//
+//===-- TestIndex.cpp -------------------------------------------*- C++ -*-===//
 //
 //                     The LLVM Compiler Infrastructure
 //