Index: clang-tools-extra/clang-doc/HTMLGenerator.cpp
===================================================================
--- clang-tools-extra/clang-doc/HTMLGenerator.cpp
+++ clang-tools-extra/clang-doc/HTMLGenerator.cpp
@@ -268,15 +268,22 @@
   return LinkNode;
 }
 
-static std::unique_ptr<HTMLNode> genTypeReference(const Reference &Type,
-                                                  StringRef CurrentDirectory) {
-  if (Type.Path.empty() && !Type.IsInGlobalNamespace)
-    return llvm::make_unique<TextNode>(Type.Name);
+static std::unique_ptr<HTMLNode>
+genTypeReference(const Reference &Type, StringRef CurrentDirectory,
+                 llvm::Optional<StringRef> JumpToSection = None) {
+  if (Type.Path.empty() && !Type.IsInGlobalNamespace) {
+    if (!JumpToSection)
+      return llvm::make_unique<TextNode>(Type.Name);
+    else
+      return genLink(Type.Name, "#" + JumpToSection.getValue());
+  }
   llvm::SmallString<128> Path =
       computeRelativePath(Type.Path, CurrentDirectory);
   llvm::sys::path::append(Path, Type.Name + ".html");
   // Paths in HTML must be in posix-style
   llvm::sys::path::native(Path, llvm::sys::path::Style::posix);
+  if (JumpToSection)
+    Path += ("#" + JumpToSection.getValue()).str();
   return genLink(Type.Name, Path);
 }
 
@@ -303,6 +310,7 @@
 
   std::vector<std::unique_ptr<TagNode>> Out;
   Out.emplace_back(llvm::make_unique<TagNode>(HTMLTag::TAG_H2, "Enums"));
+  Out.back()->Attributes.try_emplace("id", "Enums");
   Out.emplace_back(llvm::make_unique<TagNode>(HTMLTag::TAG_DIV));
   auto &DivBody = Out.back();
   for (const auto &E : Enums) {
@@ -331,6 +339,7 @@
 
   std::vector<std::unique_ptr<TagNode>> Out;
   Out.emplace_back(llvm::make_unique<TagNode>(HTMLTag::TAG_H2, "Functions"));
+  Out.back()->Attributes.try_emplace("id", "Functions");
   Out.emplace_back(llvm::make_unique<TagNode>(HTMLTag::TAG_DIV));
   auto &DivBody = Out.back();
   for (const auto &F : Functions) {
@@ -348,6 +357,7 @@
 
   std::vector<std::unique_ptr<TagNode>> Out;
   Out.emplace_back(llvm::make_unique<TagNode>(HTMLTag::TAG_H2, "Members"));
+  Out.back()->Attributes.try_emplace("id", "Members");
   Out.emplace_back(llvm::make_unique<TagNode>(HTMLTag::TAG_UL));
   auto &ULBody = Out.back();
   for (const auto &M : Members) {
@@ -371,6 +381,7 @@
 
   std::vector<std::unique_ptr<TagNode>> Out;
   Out.emplace_back(llvm::make_unique<TagNode>(HTMLTag::TAG_H2, Title));
+  Out.back()->Attributes.try_emplace("id", Title);
   Out.emplace_back(llvm::make_unique<TagNode>(HTMLTag::TAG_UL));
   auto &ULBody = Out.back();
   for (const auto &R : References)
@@ -407,6 +418,41 @@
   return Out;
 }
 
+template <typename T,
+          typename = std::enable_if<std::is_base_of<T, Info>::value>>
+static Index genInfoIndexItem(const std::vector<T> &Infos, StringRef Title) {
+  Index Idx(Title, Title);
+  for (const auto &C : Infos)
+    Idx.Children.emplace_back(C.extractName(),
+                              llvm::toHex(llvm::toStringRef(C.USR)));
+  return Idx;
+}
+
+static std::vector<std::unique_ptr<TagNode>> genHTML(const Index &Index,
+                                                     StringRef InfoPath) {
+  std::vector<std::unique_ptr<TagNode>> Out;
+  if (!Index.Name.empty()) {
+    Out.emplace_back(llvm::make_unique<TagNode>(HTMLTag::TAG_SPAN));
+    auto &SpanBody = Out.back();
+    if (!Index.JumpToSection)
+      SpanBody->Children.emplace_back(genTypeReference(Index, InfoPath));
+    else
+      SpanBody->Children.emplace_back(genTypeReference(
+          Index, InfoPath, StringRef{Index.JumpToSection.getValue()}));
+  }
+  if (Index.Children.empty())
+    return Out;
+  Out.emplace_back(llvm::make_unique<TagNode>(HTMLTag::TAG_UL));
+  const auto &UlBody = Out.back();
+  for (const auto &C : Index.Children) {
+    auto LiBody = llvm::make_unique<TagNode>(HTMLTag::TAG_LI);
+    std::vector<std::unique_ptr<TagNode>> Nodes = genHTML(C, InfoPath);
+    AppendVector(std::move(Nodes), LiBody->Children);
+    UlBody->Children.emplace_back(std::move(LiBody));
+  }
+  return Out;
+}
+
 static std::unique_ptr<HTMLNode> genHTML(const CommentInfo &I) {
   if (I.Kind == "FullComment") {
     auto FullComment = llvm::make_unique<TagNode>(HTMLTag::TAG_DIV);
@@ -453,6 +499,8 @@
 
   Out.emplace_back(
       llvm::make_unique<TagNode>(HTMLTag::TAG_H3, EnumType + I.Name));
+  Out.back()->Attributes.try_emplace("id",
+                                     llvm::toHex(llvm::toStringRef(I.USR)));
 
   std::unique_ptr<TagNode> Node = genEnumMembersBlock(I.Members);
   if (Node)
@@ -472,6 +520,10 @@
                                                      StringRef ParentInfoDir) {
   std::vector<std::unique_ptr<TagNode>> Out;
   Out.emplace_back(llvm::make_unique<TagNode>(HTMLTag::TAG_H3, I.Name));
+  // USR is used as id for functions instead of name to disambiguate function
+  // overloads.
+  Out.back()->Attributes.try_emplace("id",
+                                     llvm::toHex(llvm::toStringRef(I.USR)));
 
   Out.emplace_back(llvm::make_unique<TagNode>(HTMLTag::TAG_P));
   auto &FunctionHeader = Out.back();
@@ -508,8 +560,8 @@
   return Out;
 }
 
-static std::vector<std::unique_ptr<TagNode>> genHTML(const NamespaceInfo &I,
-                                                     std::string &InfoTitle) {
+static std::vector<std::unique_ptr<TagNode>>
+genHTML(const NamespaceInfo &I, Index &InfoIndex, std::string &InfoTitle) {
   std::vector<std::unique_ptr<TagNode>> Out;
   if (I.Name.str() == "")
     InfoTitle = "Global Namespace";
@@ -536,11 +588,21 @@
       genEnumsBlock(I.ChildEnums);
   AppendVector(std::move(ChildEnums), Out);
 
+  if (!I.ChildNamespaces.empty())
+    InfoIndex.Children.emplace_back("Namespaces", "Namespaces");
+  if (!I.ChildRecords.empty())
+    InfoIndex.Children.emplace_back("Records", "Records");
+  if (!I.ChildFunctions.empty())
+    InfoIndex.Children.emplace_back(
+        genInfoIndexItem(I.ChildFunctions, "Functions"));
+  if (!I.ChildEnums.empty())
+    InfoIndex.Children.emplace_back(genInfoIndexItem(I.ChildEnums, "Enums"));
+
   return Out;
 }
 
-static std::vector<std::unique_ptr<TagNode>> genHTML(const RecordInfo &I,
-                                                     std::string &InfoTitle) {
+static std::vector<std::unique_ptr<TagNode>>
+genHTML(const RecordInfo &I, Index &InfoIndex, std::string &InfoTitle) {
   std::vector<std::unique_ptr<TagNode>> Out;
   InfoTitle = (getTagType(I.TagType) + " " + I.Name).str();
   Out.emplace_back(llvm::make_unique<TagNode>(HTMLTag::TAG_H1, InfoTitle));
@@ -585,6 +647,16 @@
       genEnumsBlock(I.ChildEnums);
   AppendVector(std::move(ChildEnums), Out);
 
+  if (!I.Members.empty())
+    InfoIndex.Children.emplace_back("Members", "Members");
+  if (!I.ChildRecords.empty())
+    InfoIndex.Children.emplace_back("Records", "Records");
+  if (!I.ChildFunctions.empty())
+    InfoIndex.Children.emplace_back(
+        genInfoIndexItem(I.ChildFunctions, "Functions"));
+  if (!I.ChildEnums.empty())
+    InfoIndex.Children.emplace_back(genInfoIndexItem(I.ChildEnums, "Enums"));
+
   return Out;
 }
 
@@ -605,16 +677,17 @@
   HTMLFile F;
   std::string InfoTitle;
   auto MainContentNode = llvm::make_unique<TagNode>(HTMLTag::TAG_DIV);
+  Index InfoIndex;
   switch (I->IT) {
   case InfoType::IT_namespace: {
-    std::vector<std::unique_ptr<TagNode>> Nodes =
-        genHTML(*static_cast<clang::doc::NamespaceInfo *>(I), InfoTitle);
+    std::vector<std::unique_ptr<TagNode>> Nodes = genHTML(
+        *static_cast<clang::doc::NamespaceInfo *>(I), InfoIndex, InfoTitle);
     AppendVector(std::move(Nodes), MainContentNode->Children);
     break;
   }
   case InfoType::IT_record: {
-    std::vector<std::unique_ptr<TagNode>> Nodes =
-        genHTML(*static_cast<clang::doc::RecordInfo *>(I), InfoTitle);
+    std::vector<std::unique_ptr<TagNode>> Nodes = genHTML(
+        *static_cast<clang::doc::RecordInfo *>(I), InfoIndex, InfoTitle);
     AppendVector(std::move(Nodes), MainContentNode->Children);
     break;
   }
@@ -638,6 +711,9 @@
   std::vector<std::unique_ptr<TagNode>> BasicNodes =
       genCommonFileNodes(InfoTitle, I->Path, CDCtx);
   AppendVector(std::move(BasicNodes), F.Children);
+  std::vector<std::unique_ptr<TagNode>> InfoIndexHTML =
+      genHTML(InfoIndex, I->Path);
+  AppendVector(std::move(InfoIndexHTML), F.Children);
   F.Children.emplace_back(std::move(MainContentNode));
   F.Render(OS);
 
Index: clang-tools-extra/clang-doc/Representation.h
===================================================================
--- clang-tools-extra/clang-doc/Representation.h
+++ clang-tools-extra/clang-doc/Representation.h
@@ -350,12 +350,15 @@
 
 struct Index : public Reference {
   Index() = default;
+  Index(StringRef Name, StringRef JumpToSection)
+      : Reference(Name), JumpToSection(JumpToSection) {}
   Index(SymbolID USR, StringRef Name, InfoType IT, StringRef Path)
       : Reference(USR, Name, IT, Path) {}
   // This is used to look for a USR in a vector of Indexes using std::find
   bool operator==(const SymbolID &Other) const { return USR == Other; }
   bool operator<(const Index &Other) const { return Name < Other.Name; }
 
+  llvm::Optional<SmallString<16>> JumpToSection;
   std::vector<Index> Children;
 
   void sort();
Index: clang-tools-extra/unittests/clang-doc/HTMLGeneratorTest.cpp
===================================================================
--- clang-tools-extra/unittests/clang-doc/HTMLGeneratorTest.cpp
+++ clang-tools-extra/unittests/clang-doc/HTMLGeneratorTest.cpp
@@ -9,6 +9,7 @@
 #include "ClangDocTest.h"
 #include "Generators.h"
 #include "Representation.h"
+#include "Serialize.h"
 #include "gtest/gtest.h"
 
 namespace clang {
@@ -59,24 +60,60 @@
 <link rel="stylesheet" href="user-provided-stylesheet.css"/>
 <script src="index.js"></script>
 <div id="index" path=""></div>
+<ul>
+  <li>
+    <span>
+      <a href="#Namespaces">Namespaces</a>
+    </span>
+  </li>
+  <li>
+    <span>
+      <a href="#Records">Records</a>
+    </span>
+  </li>
+  <li>
+    <span>
+      <a href="#Functions">Functions</a>
+    </span>
+    <ul>
+      <li>
+        <span>
+          <a href="#0000000000000000000000000000000000000000">OneFunction</a>
+        </span>
+      </li>
+    </ul>
+  </li>
+  <li>
+    <span>
+      <a href="#Enums">Enums</a>
+    </span>
+    <ul>
+      <li>
+        <span>
+          <a href="#0000000000000000000000000000000000000000">OneEnum</a>
+        </span>
+      </li>
+    </ul>
+  </li>
+</ul>
 <div>
   <h1>namespace Namespace</h1>
-  <h2>Namespaces</h2>
+  <h2 id="Namespaces">Namespaces</h2>
   <ul>
     <li>ChildNamespace</li>
   </ul>
-  <h2>Records</h2>
+  <h2 id="Records">Records</h2>
   <ul>
     <li>ChildStruct</li>
   </ul>
-  <h2>Functions</h2>
+  <h2 id="Functions">Functions</h2>
   <div>
-    <h3>OneFunction</h3>
+    <h3 id="0000000000000000000000000000000000000000">OneFunction</h3>
     <p>OneFunction()</p>
   </div>
-  <h2>Enums</h2>
+  <h2 id="Enums">Enums</h2>
   <div>
-    <h3>enum OneEnum</h3>
+    <h3 id="0000000000000000000000000000000000000000">enum OneEnum</h3>
   </div>
 </div>
 )raw";
@@ -119,6 +156,42 @@
 <link rel="stylesheet" href="../../../clang-doc-default-stylesheet.css"/>
 <script src="../../../index.js"></script>
 <div id="index" path="X/Y/Z"></div>
+<ul>
+  <li>
+    <span>
+      <a href="#Members">Members</a>
+    </span>
+  </li>
+  <li>
+    <span>
+      <a href="#Records">Records</a>
+    </span>
+  </li>
+  <li>
+    <span>
+      <a href="#Functions">Functions</a>
+    </span>
+    <ul>
+      <li>
+        <span>
+          <a href="#0000000000000000000000000000000000000000">OneFunction</a>
+        </span>
+      </li>
+    </ul>
+  </li>
+  <li>
+    <span>
+      <a href="#Enums">Enums</a>
+    </span>
+    <ul>
+      <li>
+        <span>
+          <a href="#0000000000000000000000000000000000000000">OneEnum</a>
+        </span>
+      </li>
+    </ul>
+  </li>
+</ul>
 <div>
   <h1>class r</h1>
   <p>Defined at line 10 of test.cpp</p>
@@ -127,7 +200,7 @@
     <a href="../../../path/to/F.html">F</a>
     , G
   </p>
-  <h2>Members</h2>
+  <h2 id="Members">Members</h2>
   <ul>
     <li>
       private 
@@ -135,18 +208,18 @@
        X
     </li>
   </ul>
-  <h2>Records</h2>
+  <h2 id="Records">Records</h2>
   <ul>
     <li>ChildStruct</li>
   </ul>
-  <h2>Functions</h2>
+  <h2 id="Functions">Functions</h2>
   <div>
-    <h3>OneFunction</h3>
+    <h3 id="0000000000000000000000000000000000000000">OneFunction</h3>
     <p>OneFunction()</p>
   </div>
-  <h2>Enums</h2>
+  <h2 id="Enums">Enums</h2>
   <div>
-    <h3>enum OneEnum</h3>
+    <h3 id="0000000000000000000000000000000000000000">enum OneEnum</h3>
   </div>
 </div>
 )raw";
@@ -155,26 +228,39 @@
 }
 
 TEST(HTMLGeneratorTest, emitFunctionHTML) {
+  llvm::errs() << "1\n";
   FunctionInfo I;
+  llvm::errs() << "2\n";
   I.Name = "f";
+  llvm::errs() << "3\n";
   I.Namespace.emplace_back(EmptySID, "A", InfoType::IT_namespace);
 
+  llvm::errs() << "4\n";
   I.DefLoc = Location(10, llvm::SmallString<16>{"test.cpp"});
+  llvm::errs() << "5\n";
   I.Loc.emplace_back(12, llvm::SmallString<16>{"test.cpp"});
-
+  llvm::errs() << "6\n";
   SmallString<16> PathTo;
+  llvm::errs() << "7\n";
   llvm::sys::path::native("path/to", PathTo);
+  llvm::errs() << "8\n";
   I.ReturnType = TypeInfo(EmptySID, "float", InfoType::IT_default, PathTo);
+  llvm::errs() << "9\n";
   I.Params.emplace_back("int", PathTo, "P");
+  llvm::errs() << "1\n";
   I.IsMethod = true;
+  llvm::errs() << "2\n";
   I.Parent = Reference(EmptySID, "Parent", InfoType::IT_record);
+  llvm::errs() << "3\n";
 
   auto G = getHTMLGenerator();
   assert(G);
   std::string Buffer;
   llvm::raw_string_ostream Actual(Buffer);
   ClangDocContext CDCtx = getClangDocContext();
+  llvm::errs() << "4\n";
   auto Err = G->generateDocForInfo(&I, Actual, CDCtx);
+  llvm::errs() << "5\n";
   assert(!Err);
   std::string Expected = R"raw(<!DOCTYPE html>
 <meta charset="utf-8"/>
@@ -183,7 +269,7 @@
 <script src="index.js"></script>
 <div id="index" path=""></div>
 <div>
-  <h3>f</h3>
+  <h3 id="0000000000000000000000000000000000000000">f</h3>
   <p>
     <a href="path/to/float.html">float</a>
      f(
@@ -193,8 +279,10 @@
   <p>Defined at line 10 of test.cpp</p>
 </div>
 )raw";
+  llvm::errs() << "6\n";
 
   EXPECT_EQ(Expected, Actual.str());
+  llvm::errs() << "7\n";
 }
 
 TEST(HTMLGeneratorTest, emitEnumHTML) {
@@ -222,7 +310,7 @@
 <script src="index.js"></script>
 <div id="index" path=""></div>
 <div>
-  <h3>enum class e</h3>
+  <h3 id="0000000000000000000000000000000000000000">enum class e</h3>
   <ul>
     <li>X</li>
   </ul>
@@ -293,7 +381,7 @@
 <script src="index.js"></script>
 <div id="index" path=""></div>
 <div>
-  <h3>f</h3>
+  <h3 id="0000000000000000000000000000000000000000">f</h3>
   <p>void f(int I, int J)</p>
   <p>Defined at line 10 of test.cpp</p>
   <div>