19 files changed, 1460 insertions, 318 deletions

diff --git a/tools/llvm-cov/CMakeLists.txt b/tools/llvm-cov/CMakeLists.txt
index 193218a6639f2..e22828e11effe 100644
--- a/tools/llvm-cov/CMakeLists.txt
+++ b/tools/llvm-cov/CMakeLists.txt
@@ -1,4 +1,4 @@
-set(LLVM_LINK_COMPONENTS core support object profiledata)
+set(LLVM_LINK_COMPONENTS core support object coverage profiledata)
 
 add_llvm_tool(llvm-cov
   llvm-cov.cpp
@@ -8,5 +8,7 @@ add_llvm_tool(llvm-cov
   CoverageReport.cpp
   CoverageSummaryInfo.cpp
   SourceCoverageView.cpp
+  SourceCoverageViewHTML.cpp
+  SourceCoverageViewText.cpp
   TestingSupport.cpp
   )
diff --git a/tools/llvm-cov/CodeCoverage.cpp b/tools/llvm-cov/CodeCoverage.cpp
index 8dc4d665f23ca..0a4d1a67d6105 100644
--- a/tools/llvm-cov/CodeCoverage.cpp
+++ b/tools/llvm-cov/CodeCoverage.cpp
@@ -13,24 +13,25 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "RenderingSupport.h"
 #include "CoverageFilters.h"
 #include "CoverageReport.h"
 #include "CoverageViewOptions.h"
+#include "RenderingSupport.h"
 #include "SourceCoverageView.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/Triple.h"
-#include "llvm/ProfileData/CoverageMapping.h"
+#include "llvm/ProfileData/Coverage/CoverageMapping.h"
 #include "llvm/ProfileData/InstrProfReader.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/Format.h"
-#include "llvm/Support/ManagedStatic.h"
+#include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/Path.h"
-#include "llvm/Support/PrettyStackTrace.h"
 #include "llvm/Support/Process.h"
-#include "llvm/Support/Signals.h"
+#include "llvm/Support/Program.h"
+#include "llvm/Support/ThreadPool.h"
+#include "llvm/Support/ToolOutputFile.h"
 #include <functional>
 #include <system_error>
 
@@ -51,28 +52,47 @@ public:
   /// \brief Print the error message to the error output stream.
   void error(const Twine &Message, StringRef Whence = "");
 
+  /// \brief Record (but do not print) an error message in a thread-safe way.
+  void deferError(const Twine &Message, StringRef Whence = "");
+
+  /// \brief Record (but do not print) a warning message in a thread-safe way.
+  void deferWarning(const Twine &Message, StringRef Whence = "");
+
+  /// \brief Print (and then clear) all deferred error and warning messages.
+  void consumeDeferredMessages();
+
+  /// \brief Append a reference to a private copy of \p Path into SourceFiles.
+  void addCollectedPath(const std::string &Path);
+
   /// \brief Return a memory buffer for the given source file.
   ErrorOr<const MemoryBuffer &> getSourceFile(StringRef SourceFile);
 
   /// \brief Create source views for the expansions of the view.
   void attachExpansionSubViews(SourceCoverageView &View,
                                ArrayRef<ExpansionRecord> Expansions,
-                               CoverageMapping &Coverage);
+                               const CoverageMapping &Coverage);
 
   /// \brief Create the source view of a particular function.
   std::unique_ptr<SourceCoverageView>
-  createFunctionView(const FunctionRecord &Function, CoverageMapping &Coverage);
+  createFunctionView(const FunctionRecord &Function,
+                     const CoverageMapping &Coverage);
 
   /// \brief Create the main source view of a particular source file.
   std::unique_ptr<SourceCoverageView>
-  createSourceFileView(StringRef SourceFile, CoverageMapping &Coverage);
+  createSourceFileView(StringRef SourceFile, const CoverageMapping &Coverage);
 
-  /// \brief Load the coverage mapping data. Return true if an error occured.
+  /// \brief Load the coverage mapping data. Return nullptr if an error occured.
   std::unique_ptr<CoverageMapping> load();
 
+  /// \brief If a demangler is available, demangle all symbol names.
+  void demangleSymbols(const CoverageMapping &Coverage);
+
+  /// \brief Demangle \p Sym if possible. Otherwise, just return \p Sym.
+  StringRef getSymbolForHumans(StringRef Sym) const;
+
   int run(Command Cmd, int argc, const char **argv);
 
-  typedef std::function<int(int, const char **)> CommandLineParserType;
+  typedef llvm::function_ref<int(int, const char **)> CommandLineParserType;
 
   int show(int argc, const char **argv,
            CommandLineParserType commandLineParser);
@@ -84,25 +104,69 @@ public:
   CoverageViewOptions ViewOpts;
   std::string PGOFilename;
   CoverageFiltersMatchAll Filters;
-  std::vector<std::string> SourceFiles;
-  std::vector<std::pair<std::string, std::unique_ptr<MemoryBuffer>>>
-      LoadedSourceFiles;
+  std::vector<StringRef> SourceFiles;
   bool CompareFilenamesOnly;
   StringMap<std::string> RemappedFilenames;
   std::string CoverageArch;
+
+private:
+  /// A cache for demangled symbol names.
+  StringMap<std::string> DemangledNames;
+
+  /// File paths (absolute, or otherwise) to input source files.
+  std::vector<std::string> CollectedPaths;
+
+  /// Errors and warnings which have not been printed.
+  std::mutex DeferredMessagesLock;
+  std::vector<std::string> DeferredMessages;
+
+  /// A container for input source file buffers.
+  std::mutex LoadedSourceFilesLock;
+  std::vector<std::pair<std::string, std::unique_ptr<MemoryBuffer>>>
+      LoadedSourceFiles;
 };
 }
 
-void CodeCoverageTool::error(const Twine &Message, StringRef Whence) {
-  errs() << "error: ";
+static std::string getErrorString(const Twine &Message, StringRef Whence,
+                                  bool Warning) {
+  std::string Str = (Warning ? "warning" : "error");
+  Str += ": ";
   if (!Whence.empty())
-    errs() << Whence << ": ";
-  errs() << Message << "\n";
+    Str += Whence.str() + ": ";
+  Str += Message.str() + "\n";
+  return Str;
+}
+
+void CodeCoverageTool::error(const Twine &Message, StringRef Whence) {
+  errs() << getErrorString(Message, Whence, false);
+}
+
+void CodeCoverageTool::deferError(const Twine &Message, StringRef Whence) {
+  std::unique_lock<std::mutex> Guard{DeferredMessagesLock};
+  DeferredMessages.emplace_back(getErrorString(Message, Whence, false));
+}
+
+void CodeCoverageTool::deferWarning(const Twine &Message, StringRef Whence) {
+  std::unique_lock<std::mutex> Guard{DeferredMessagesLock};
+  DeferredMessages.emplace_back(getErrorString(Message, Whence, true));
+}
+
+void CodeCoverageTool::consumeDeferredMessages() {
+  std::unique_lock<std::mutex> Guard{DeferredMessagesLock};
+  for (const std::string &Message : DeferredMessages)
+    ViewOpts.colored_ostream(errs(), raw_ostream::RED) << Message;
+  DeferredMessages.clear();
+}
+
+void CodeCoverageTool::addCollectedPath(const std::string &Path) {
+  CollectedPaths.push_back(Path);
+  SourceFiles.emplace_back(CollectedPaths.back());
 }
 
 ErrorOr<const MemoryBuffer &>
 CodeCoverageTool::getSourceFile(StringRef SourceFile) {
   // If we've remapped filenames, look up the real location for this file.
+  std::unique_lock<std::mutex> Guard{LoadedSourceFilesLock};
   if (!RemappedFilenames.empty()) {
     auto Loc = RemappedFilenames.find(SourceFile);
     if (Loc != RemappedFilenames.end())
@@ -113,17 +177,16 @@ CodeCoverageTool::getSourceFile(StringRef SourceFile) {
       return *Files.second;
   auto Buffer = MemoryBuffer::getFile(SourceFile);
   if (auto EC = Buffer.getError()) {
-    error(EC.message(), SourceFile);
+    deferError(EC.message(), SourceFile);
     return EC;
   }
   LoadedSourceFiles.emplace_back(SourceFile, std::move(Buffer.get()));
   return *LoadedSourceFiles.back().second;
 }
 
-void
-CodeCoverageTool::attachExpansionSubViews(SourceCoverageView &View,
-                                          ArrayRef<ExpansionRecord> Expansions,
-                                          CoverageMapping &Coverage) {
+void CodeCoverageTool::attachExpansionSubViews(
+    SourceCoverageView &View, ArrayRef<ExpansionRecord> Expansions,
+    const CoverageMapping &Coverage) {
   if (!ViewOpts.ShowExpandedRegions)
     return;
   for (const auto &Expansion : Expansions) {
@@ -135,8 +198,9 @@ CodeCoverageTool::attachExpansionSubViews(SourceCoverageView &View,
       continue;
 
     auto SubViewExpansions = ExpansionCoverage.getExpansions();
-    auto SubView = llvm::make_unique<SourceCoverageView>(
-        SourceBuffer.get(), ViewOpts, std::move(ExpansionCoverage));
+    auto SubView =
+        SourceCoverageView::create(Expansion.Function.Name, SourceBuffer.get(),
+                                   ViewOpts, std::move(ExpansionCoverage));
     attachExpansionSubViews(*SubView, SubViewExpansions, Coverage);
     View.addExpansion(Expansion.Region, std::move(SubView));
   }
@@ -144,7 +208,7 @@ CodeCoverageTool::attachExpansionSubViews(SourceCoverageView &View,
 
 std::unique_ptr<SourceCoverageView>
 CodeCoverageTool::createFunctionView(const FunctionRecord &Function,
-                                     CoverageMapping &Coverage) {
+                                     const CoverageMapping &Coverage) {
   auto FunctionCoverage = Coverage.getCoverageForFunction(Function);
   if (FunctionCoverage.empty())
     return nullptr;
@@ -153,8 +217,9 @@ CodeCoverageTool::createFunctionView(const FunctionRecord &Function,
     return nullptr;
 
   auto Expansions = FunctionCoverage.getExpansions();
-  auto View = llvm::make_unique<SourceCoverageView>(
-      SourceBuffer.get(), ViewOpts, std::move(FunctionCoverage));
+  auto View = SourceCoverageView::create(getSymbolForHumans(Function.Name),
+                                         SourceBuffer.get(), ViewOpts,
+                                         std::move(FunctionCoverage));
   attachExpansionSubViews(*View, Expansions, Coverage);
 
   return View;
@@ -162,7 +227,7 @@ CodeCoverageTool::createFunctionView(const FunctionRecord &Function,
 
 std::unique_ptr<SourceCoverageView>
 CodeCoverageTool::createSourceFileView(StringRef SourceFile,
-                                       CoverageMapping &Coverage) {
+                                       const CoverageMapping &Coverage) {
   auto SourceBuffer = getSourceFile(SourceFile);
   if (!SourceBuffer)
     return nullptr;
@@ -171,15 +236,16 @@ CodeCoverageTool::createSourceFileView(StringRef SourceFile,
     return nullptr;
 
   auto Expansions = FileCoverage.getExpansions();
-  auto View = llvm::make_unique<SourceCoverageView>(
-      SourceBuffer.get(), ViewOpts, std::move(FileCoverage));
+  auto View = SourceCoverageView::create(SourceFile, SourceBuffer.get(),
+                                         ViewOpts, std::move(FileCoverage));
   attachExpansionSubViews(*View, Expansions, Coverage);
 
-  for (auto Function : Coverage.getInstantiations(SourceFile)) {
+  for (const auto *Function : Coverage.getInstantiations(SourceFile)) {
     auto SubViewCoverage = Coverage.getCoverageForFunction(*Function);
     auto SubViewExpansions = SubViewCoverage.getExpansions();
-    auto SubView = llvm::make_unique<SourceCoverageView>(
-        SourceBuffer.get(), ViewOpts, std::move(SubViewCoverage));
+    auto SubView = SourceCoverageView::create(
+        getSymbolForHumans(Function->Name), SourceBuffer.get(), ViewOpts,
+        std::move(SubViewCoverage));
     attachExpansionSubViews(*SubView, SubViewExpansions, Coverage);
 
     if (SubView) {
@@ -210,10 +276,9 @@ std::unique_ptr<CoverageMapping> CodeCoverageTool::load() {
     errs() << "warning: profile data may be out of date - object is newer\n";
   auto CoverageOrErr = CoverageMapping::load(ObjectFilename, PGOFilename,
                                              CoverageArch);
-  if (std::error_code EC = CoverageOrErr.getError()) {
+  if (Error E = CoverageOrErr.takeError()) {
     colored_ostream(errs(), raw_ostream::RED)
-        << "error: Failed to load coverage: " << EC.message();
-    errs() << "\n";
+        << "error: Failed to load coverage: " << toString(std::move(E)) << "\n";
     return nullptr;
   }
   auto Coverage = std::move(CoverageOrErr.get());
@@ -237,15 +302,95 @@ std::unique_ptr<CoverageMapping> CodeCoverageTool::load() {
     }
   }
 
+  demangleSymbols(*Coverage);
+
   return Coverage;
 }
 
-int CodeCoverageTool::run(Command Cmd, int argc, const char **argv) {
-  // Print a stack trace if we signal out.
-  sys::PrintStackTraceOnErrorSignal();
-  PrettyStackTraceProgram X(argc, argv);
-  llvm_shutdown_obj Y; // Call llvm_shutdown() on exit.
+void CodeCoverageTool::demangleSymbols(const CoverageMapping &Coverage) {
+  if (!ViewOpts.hasDemangler())
+    return;
+
+  // Pass function names to the demangler in a temporary file.
+  int InputFD;
+  SmallString<256> InputPath;
+  std::error_code EC =
+      sys::fs::createTemporaryFile("demangle-in", "list", InputFD, InputPath);
+  if (EC) {
+    error(InputPath, EC.message());
+    return;
+  }
+  tool_output_file InputTOF{InputPath, InputFD};
+
+  unsigned NumSymbols = 0;
+  for (const auto &Function : Coverage.getCoveredFunctions()) {
+    InputTOF.os() << Function.Name << '\n';
+    ++NumSymbols;
+  }
+  InputTOF.os().close();
+
+  // Use another temporary file to store the demangler's output.
+  int OutputFD;
+  SmallString<256> OutputPath;
+  EC = sys::fs::createTemporaryFile("demangle-out", "list", OutputFD,
+                                    OutputPath);
+  if (EC) {
+    error(OutputPath, EC.message());
+    return;
+  }
+  tool_output_file OutputTOF{OutputPath, OutputFD};
+  OutputTOF.os().close();
+
+  // Invoke the demangler.
+  std::vector<const char *> ArgsV;
+  for (const std::string &Arg : ViewOpts.DemanglerOpts)
+    ArgsV.push_back(Arg.c_str());
+  ArgsV.push_back(nullptr);
+  StringRef InputPathRef = InputPath.str();
+  StringRef OutputPathRef = OutputPath.str();
+  StringRef StderrRef;
+  const StringRef *Redirects[] = {&InputPathRef, &OutputPathRef, &StderrRef};
+  std::string ErrMsg;
+  int RC = sys::ExecuteAndWait(ViewOpts.DemanglerOpts[0], ArgsV.data(),
+                               /*env=*/nullptr, Redirects, /*secondsToWait=*/0,
+                               /*memoryLimit=*/0, &ErrMsg);
+  if (RC) {
+    error(ErrMsg, ViewOpts.DemanglerOpts[0]);
+    return;
+  }
 
+  // Parse the demangler's output.
+  auto BufOrError = MemoryBuffer::getFile(OutputPath);
+  if (!BufOrError) {
+    error(OutputPath, BufOrError.getError().message());
+    return;
+  }
+
+  std::unique_ptr<MemoryBuffer> DemanglerBuf = std::move(*BufOrError);
+
+  SmallVector<StringRef, 8> Symbols;
+  StringRef DemanglerData = DemanglerBuf->getBuffer();
+  DemanglerData.split(Symbols, '\n', /*MaxSplit=*/NumSymbols,
+                      /*KeepEmpty=*/false);
+  if (Symbols.size() != NumSymbols) {
+    error("Demangler did not provide expected number of symbols");
+    return;
+  }
+
+  // Cache the demangled names.
+  unsigned I = 0;
+  for (const auto &Function : Coverage.getCoveredFunctions())
+    DemangledNames[Function.Name] = Symbols[I++];
+}
+
+StringRef CodeCoverageTool::getSymbolForHumans(StringRef Sym) const {
+  const auto DemangledName = DemangledNames.find(Sym);
+  if (DemangledName == DemangledNames.end())
+    return Sym;
+  return DemangledName->getValue();
+}
+
+int CodeCoverageTool::run(Command Cmd, int argc, const char **argv) {
   cl::opt<std::string, true> ObjectFilename(
       cl::Positional, cl::Required, cl::location(this->ObjectFilename),
       cl::desc("Covered executable or object file."));
@@ -264,6 +409,15 @@ int CodeCoverageTool::run(Command Cmd, int argc, const char **argv) {
   cl::opt<bool> DebugDump("dump", cl::Optional,
                           cl::desc("Show internal debug dump"));
 
+  cl::opt<CoverageViewOptions::OutputFormat> Format(
+      "format", cl::desc("Output format for line-based coverage reports"),
+      cl::values(clEnumValN(CoverageViewOptions::OutputFormat::Text, "text",
+                            "Text output"),
+                 clEnumValN(CoverageViewOptions::OutputFormat::HTML, "html",
+                            "HTML output"),
+                 clEnumValEnd),
+      cl::init(CoverageViewOptions::OutputFormat::Text));
+
   cl::opt<bool> FilenameEquivalence(
       "filename-equivalence", cl::Optional,
       cl::desc("Treat source files as equivalent to paths in the coverage data "
@@ -310,14 +464,39 @@ int CodeCoverageTool::run(Command Cmd, int argc, const char **argv) {
       "use-color", cl::desc("Emit colored output (default=autodetect)"),
       cl::init(cl::BOU_UNSET));
 
+  cl::list<std::string> DemanglerOpts(
+      "Xdemangler", cl::desc("<demangler-path>|<demangler-option>"));
+
   auto commandLineParser = [&, this](int argc, const char **argv) -> int {
     cl::ParseCommandLineOptions(argc, argv, "LLVM code coverage tool\n");
     ViewOpts.Debug = DebugDump;
     CompareFilenamesOnly = FilenameEquivalence;
 
-    ViewOpts.Colors = UseColor == cl::BOU_UNSET
-                          ? sys::Process::StandardOutHasColors()
-                          : UseColor == cl::BOU_TRUE;
+    ViewOpts.Format = Format;
+    switch (ViewOpts.Format) {
+    case CoverageViewOptions::OutputFormat::Text:
+      ViewOpts.Colors = UseColor == cl::BOU_UNSET
+                            ? sys::Process::StandardOutHasColors()
+                            : UseColor == cl::BOU_TRUE;
+      break;
+    case CoverageViewOptions::OutputFormat::HTML:
+      if (UseColor == cl::BOU_FALSE)
+        error("Color output cannot be disabled when generating html.");
+      ViewOpts.Colors = true;
+      break;
+    }
+
+    // If a demangler is supplied, check if it exists and register it.
+    if (DemanglerOpts.size()) {
+      auto DemanglerPathOrErr = sys::findProgramByName(DemanglerOpts[0]);
+      if (!DemanglerPathOrErr) {
+        error("Could not find the demangler!",
+              DemanglerPathOrErr.getError().message());
+        return 1;
+      }
+      DemanglerOpts[0] = *DemanglerPathOrErr;
+      ViewOpts.DemanglerOpts.swap(DemanglerOpts);
+    }
 
     // Create the function filters
     if (!NameFilters.empty() || !NameRegexFilters.empty()) {
@@ -363,7 +542,7 @@ int CodeCoverageTool::run(Command Cmd, int argc, const char **argv) {
           errs() << "error: " << File << ": " << EC.message();
           return 1;
         }
-      SourceFiles.push_back(Path.str());
+      addCollectedPath(Path.str());
     }
     return 0;
   };
@@ -406,6 +585,12 @@ int CodeCoverageTool::show(int argc, const char **argv,
                                    cl::desc("Show function instantiations"),
                                    cl::cat(ViewCategory));
 
+  cl::opt<std::string> ShowOutputDirectory(
+      "output-dir", cl::init(""),
+      cl::desc("Directory in which coverage information is written out"));
+  cl::alias ShowOutputDirectoryA("o", cl::desc("Alias for --output-dir"),
+                                 cl::aliasopt(ShowOutputDirectory));
+
   auto Err = commandLineParser(argc, argv);
   if (Err)
     return Err;
@@ -417,30 +602,46 @@ int CodeCoverageTool::show(int argc, const char **argv,
   ViewOpts.ShowLineStatsOrRegionMarkers = ShowBestLineRegionsCounts;
   ViewOpts.ShowExpandedRegions = ShowExpansions;
   ViewOpts.ShowFunctionInstantiations = ShowInstantiations;
+  ViewOpts.ShowOutputDirectory = ShowOutputDirectory;
+
+  if (ViewOpts.hasOutputDirectory()) {
+    if (auto E = sys::fs::create_directories(ViewOpts.ShowOutputDirectory)) {
+      error("Could not create output directory!", E.message());
+      return 1;
+    }
+  }
 
   auto Coverage = load();
   if (!Coverage)
     return 1;
 
+  auto Printer = CoveragePrinter::create(ViewOpts);
+
   if (!Filters.empty()) {
-    // Show functions
+    auto OSOrErr = Printer->createViewFile("functions", /*InToplevel=*/true);
+    if (Error E = OSOrErr.takeError()) {
+      error("Could not create view file!", toString(std::move(E)));
+      return 1;
+    }
+    auto OS = std::move(OSOrErr.get());
+
+    // Show functions.
     for (const auto &Function : Coverage->getCoveredFunctions()) {
       if (!Filters.matches(Function))
         continue;
 
       auto mainView = createFunctionView(Function, *Coverage);
       if (!mainView) {
-        ViewOpts.colored_ostream(outs(), raw_ostream::RED)
-            << "warning: Could not read coverage for '" << Function.Name;
-        outs() << "\n";
+        ViewOpts.colored_ostream(errs(), raw_ostream::RED)
+            << "warning: Could not read coverage for '" << Function.Name << "'."
+            << "\n";
         continue;
       }
-      ViewOpts.colored_ostream(outs(), raw_ostream::CYAN) << Function.Name
-                                                          << ":";
-      outs() << "\n";
-      mainView->render(outs(), /*WholeFile=*/false);
-      outs() << "\n";
+
+      mainView->print(*OS.get(), /*WholeFile=*/false, /*ShowSourceName=*/true);
     }
+
+    Printer->closeViewFile(std::move(OS));
     return 0;
   }
 
@@ -448,28 +649,49 @@ int CodeCoverageTool::show(int argc, const char **argv,
   bool ShowFilenames = SourceFiles.size() != 1;
 
   if (SourceFiles.empty())
-    // Get the source files from the function coverage mapping
+    // Get the source files from the function coverage mapping.
     for (StringRef Filename : Coverage->getUniqueSourceFiles())
       SourceFiles.push_back(Filename);
 
-  for (const auto &SourceFile : SourceFiles) {
-    auto mainView = createSourceFileView(SourceFile, *Coverage);
-    if (!mainView) {
-      ViewOpts.colored_ostream(outs(), raw_ostream::RED)
-          << "warning: The file '" << SourceFile << "' isn't covered.";
-      outs() << "\n";
-      continue;
+  // Create an index out of the source files.
+  if (ViewOpts.hasOutputDirectory()) {
+    if (Error E = Printer->createIndexFile(SourceFiles)) {
+      error("Could not create index file!", toString(std::move(E)));
+      return 1;
     }
+  }
 
-    if (ShowFilenames) {
-      ViewOpts.colored_ostream(outs(), raw_ostream::CYAN) << SourceFile << ":";
-      outs() << "\n";
-    }
-    mainView->render(outs(), /*Wholefile=*/true);
-    if (SourceFiles.size() > 1)
-      outs() << "\n";
+  // In -output-dir mode, it's safe to use multiple threads to print files.
+  unsigned ThreadCount = 1;
+  if (ViewOpts.hasOutputDirectory())
+    ThreadCount = std::thread::hardware_concurrency();
+  ThreadPool Pool(ThreadCount);
+
+  for (StringRef SourceFile : SourceFiles) {
+    Pool.async([this, SourceFile, &Coverage, &Printer, ShowFilenames] {
+      auto View = createSourceFileView(SourceFile, *Coverage);
+      if (!View) {
+        deferWarning("The file '" + SourceFile.str() + "' isn't covered.");
+        return;
+      }
+
+      auto OSOrErr = Printer->createViewFile(SourceFile, /*InToplevel=*/false);
+      if (Error E = OSOrErr.takeError()) {
+        deferError("Could not create view file!", toString(std::move(E)));
+        return;
+      }
+      auto OS = std::move(OSOrErr.get());
+
+      View->print(*OS.get(), /*Wholefile=*/true,
+                  /*ShowSourceName=*/ShowFilenames);
+      Printer->closeViewFile(std::move(OS));
+    });
   }
 
+  Pool.wait();
+
+  consumeDeferredMessages();
+
   return 0;
 }
 
@@ -479,6 +701,9 @@ int CodeCoverageTool::report(int argc, const char **argv,
   if (Err)
     return Err;
 
+  if (ViewOpts.Format == CoverageViewOptions::OutputFormat::HTML)
+    error("HTML output for summary reports is not yet supported.");
+
   auto Coverage = load();
   if (!Coverage)
     return 1;
diff --git a/tools/llvm-cov/CoverageFilters.h b/tools/llvm-cov/CoverageFilters.h
index dc5dc98807b1a..756c4b47872c1 100644
--- a/tools/llvm-cov/CoverageFilters.h
+++ b/tools/llvm-cov/CoverageFilters.h
@@ -14,7 +14,7 @@
 #ifndef LLVM_COV_COVERAGEFILTERS_H
 #define LLVM_COV_COVERAGEFILTERS_H
 
-#include "llvm/ProfileData/CoverageMapping.h"
+#include "llvm/ProfileData/Coverage/CoverageMapping.h"
 #include <memory>
 #include <vector>
 
diff --git a/tools/llvm-cov/CoverageReport.cpp b/tools/llvm-cov/CoverageReport.cpp
index ed01a2e154f1b..10e53b3f1f723 100644
--- a/tools/llvm-cov/CoverageReport.cpp
+++ b/tools/llvm-cov/CoverageReport.cpp
@@ -171,7 +171,7 @@ void CoverageReport::render(const FunctionCoverageSummary &Function,
   OS << "\n";
 }
 
-void CoverageReport::renderFunctionReports(ArrayRef<std::string> Files,
+void CoverageReport::renderFunctionReports(ArrayRef<StringRef> Files,
                                            raw_ostream &OS) {
   adjustColumnWidths(Coverage.get());
   bool isFirst = true;
diff --git a/tools/llvm-cov/CoverageReport.h b/tools/llvm-cov/CoverageReport.h
index 7ec3df90b8f92..bb3d734b52a54 100644
--- a/tools/llvm-cov/CoverageReport.h
+++ b/tools/llvm-cov/CoverageReport.h
@@ -32,7 +32,7 @@ public:
                  std::unique_ptr<coverage::CoverageMapping> Coverage)
       : Options(Options), Coverage(std::move(Coverage)) {}
 
-  void renderFunctionReports(ArrayRef<std::string> Files, raw_ostream &OS);
+  void renderFunctionReports(ArrayRef<StringRef> Files, raw_ostream &OS);
 
   void renderFileReports(raw_ostream &OS);
 };
diff --git a/tools/llvm-cov/CoverageSummaryInfo.h b/tools/llvm-cov/CoverageSummaryInfo.h
index c393b00d32a43..822742b635e96 100644
--- a/tools/llvm-cov/CoverageSummaryInfo.h
+++ b/tools/llvm-cov/CoverageSummaryInfo.h
@@ -15,7 +15,7 @@
 #ifndef LLVM_COV_COVERAGESUMMARYINFO_H
 #define LLVM_COV_COVERAGESUMMARYINFO_H
 
-#include "llvm/ProfileData/CoverageMapping.h"
+#include "llvm/ProfileData/Coverage/CoverageMapping.h"
 #include "llvm/Support/raw_ostream.h"
 
 namespace llvm {
@@ -47,6 +47,8 @@ struct RegionCoverageInfo {
   bool isFullyCovered() const { return Covered == NumRegions; }
 
   double getPercentCovered() const {
+    if (NumRegions == 0)
+      return 0.0;
     return double(Covered) / double(NumRegions) * 100.0;
   }
 };
@@ -83,6 +85,8 @@ struct LineCoverageInfo {
   bool isFullyCovered() const { return Covered == (NumLines - NonCodeLines); }
 
   double getPercentCovered() const {
+    if (NumLines - NonCodeLines == 0)
+      return 0.0;
     return double(Covered) / double(NumLines - NonCodeLines) * 100.0;
   }
 };
@@ -109,6 +113,8 @@ struct FunctionCoverageInfo {
   bool isFullyCovered() const { return Executed == NumFunctions; }
 
   double getPercentCovered() const {
+    if (NumFunctions == 0)
+      return 0.0;
     return double(Executed) / double(NumFunctions) * 100.0;
   }
 };
diff --git a/tools/llvm-cov/CoverageViewOptions.h b/tools/llvm-cov/CoverageViewOptions.h
index 1208fad791766..350c264a28764 100644
--- a/tools/llvm-cov/CoverageViewOptions.h
+++ b/tools/llvm-cov/CoverageViewOptions.h
@@ -11,11 +11,17 @@
 #define LLVM_COV_COVERAGEVIEWOPTIONS_H
 
 #include "RenderingSupport.h"
+#include <vector>
 
 namespace llvm {
 
 /// \brief The options for displaying the code coverage information.
 struct CoverageViewOptions {
+  enum class OutputFormat {
+    Text,
+    HTML
+  };
+
   bool Debug;
   bool Colors;
   bool ShowLineNumbers;
@@ -25,12 +31,21 @@ struct CoverageViewOptions {
   bool ShowExpandedRegions;
   bool ShowFunctionInstantiations;
   bool ShowFullFilenames;
+  OutputFormat Format;
+  std::string ShowOutputDirectory;
+  std::vector<std::string> DemanglerOpts;
 
   /// \brief Change the output's stream color if the colors are enabled.
   ColoredRawOstream colored_ostream(raw_ostream &OS,
                                     raw_ostream::Colors Color) const {
     return llvm::colored_ostream(OS, Color, Colors);
   }
+
+  /// \brief Check if an output directory has been specified.
+  bool hasOutputDirectory() const { return !ShowOutputDirectory.empty(); }
+
+  /// \brief Check if a demangler has been specified.
+  bool hasDemangler() const { return !DemanglerOpts.empty(); }
 };
 }
 
diff --git a/tools/llvm-cov/LLVMBuild.txt b/tools/llvm-cov/LLVMBuild.txt
index d6eb74de0d4bf..33f51fb2ed5a9 100644
--- a/tools/llvm-cov/LLVMBuild.txt
+++ b/tools/llvm-cov/LLVMBuild.txt
@@ -19,4 +19,4 @@
 type = Tool
 name = llvm-cov
 parent = Tools
-required_libraries = ProfileData Support Instrumentation
+required_libraries = Coverage Support Instrumentation
diff --git a/tools/llvm-cov/Makefile b/tools/llvm-cov/Makefile
deleted file mode 100644
index 6e32b4d233d7e..0000000000000
--- a/tools/llvm-cov/Makefile
+++ /dev/null
@@ -1,17 +0,0 @@
-##===- tools/llvm-cov/Makefile -----------------------------*- Makefile -*-===##
-# 
-#                     The LLVM Compiler Infrastructure
-#
-# This file is distributed under the University of Illinois Open Source
-# License. See LICENSE.TXT for details.
-# 
-##===----------------------------------------------------------------------===##
-
-LEVEL := ../..
-TOOLNAME := llvm-cov
-LINK_COMPONENTS := core support profiledata object
-
-# This tool has no plugins, optimize startup time.
-TOOL_NO_EXPORTS := 1
-
-include $(LEVEL)/Makefile.common
diff --git a/tools/llvm-cov/RenderingSupport.h b/tools/llvm-cov/RenderingSupport.h
index 3ef155d3fd4bb..aa70fbc23e3c0 100644
--- a/tools/llvm-cov/RenderingSupport.h
+++ b/tools/llvm-cov/RenderingSupport.h
@@ -55,6 +55,7 @@ inline ColoredRawOstream colored_ostream(raw_ostream &OS,
     OS.changeColor(Color, Bold, BG);
   return ColoredRawOstream(OS, IsColorUsed);
 }
-}
+
+} // namespace llvm
 
 #endif // LLVM_COV_RENDERINGSUPPORT_H
diff --git a/tools/llvm-cov/SourceCoverageView.cpp b/tools/llvm-cov/SourceCoverageView.cpp
index 58c8a67952946..baf7c148bb800 100644
--- a/tools/llvm-cov/SourceCoverageView.cpp
+++ b/tools/llvm-cov/SourceCoverageView.cpp
@@ -6,80 +6,82 @@
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
-//
-// This class implements rendering for code coverage of source code.
-//
+///
+/// \file This class implements rendering for code coverage of source code.
+///
 //===----------------------------------------------------------------------===//
 
 #include "SourceCoverageView.h"
-#include "llvm/ADT/Optional.h"
+#include "SourceCoverageViewHTML.h"
+#include "SourceCoverageViewText.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/StringExtras.h"
+#include "llvm/Support/FileSystem.h"
 #include "llvm/Support/LineIterator.h"
+#include "llvm/Support/Path.h"
 
 using namespace llvm;
 
-void SourceCoverageView::renderLine(
-    raw_ostream &OS, StringRef Line, int64_t LineNumber,
-    const coverage::CoverageSegment *WrappedSegment,
-    ArrayRef<const coverage::CoverageSegment *> Segments,
-    unsigned ExpansionCol) {
-  Optional<raw_ostream::Colors> Highlight;
-  SmallVector<std::pair<unsigned, unsigned>, 2> HighlightedRanges;
-
-  // The first segment overlaps from a previous line, so we treat it specially.
-  if (WrappedSegment && WrappedSegment->HasCount && WrappedSegment->Count == 0)
-    Highlight = raw_ostream::RED;
-
-  // Output each segment of the line, possibly highlighted.
-  unsigned Col = 1;
-  for (const auto *S : Segments) {
-    unsigned End = std::min(S->Col, static_cast<unsigned>(Line.size()) + 1);
-    colored_ostream(OS, Highlight ? *Highlight : raw_ostream::SAVEDCOLOR,
-                    Options.Colors && Highlight, /*Bold=*/false, /*BG=*/true)
-        << Line.substr(Col - 1, End - Col);
-    if (Options.Debug && Highlight)
-      HighlightedRanges.push_back(std::make_pair(Col, End));
-    Col = End;
-    if (Col == ExpansionCol)
-      Highlight = raw_ostream::CYAN;
-    else if (S->HasCount && S->Count == 0)
-      Highlight = raw_ostream::RED;
-    else
-      Highlight = None;
-  }
+void CoveragePrinter::StreamDestructor::operator()(raw_ostream *OS) const {
+  if (OS == &outs())
+    return;
+  delete OS;
+}
 
-  // Show the rest of the line
-  colored_ostream(OS, Highlight ? *Highlight : raw_ostream::SAVEDCOLOR,
-                  Options.Colors && Highlight, /*Bold=*/false, /*BG=*/true)
-      << Line.substr(Col - 1, Line.size() - Col + 1);
-  OS << "\n";
-
-  if (Options.Debug) {
-    for (const auto &Range : HighlightedRanges)
-      errs() << "Highlighted line " << LineNumber << ", " << Range.first
-             << " -> " << Range.second << "\n";
-    if (Highlight)
-      errs() << "Highlighted line " << LineNumber << ", " << Col << " -> ?\n";
-  }
+std::string CoveragePrinter::getOutputPath(StringRef Path, StringRef Extension,
+                                           bool InToplevel, bool Relative) {
+  assert(Extension.size() && "The file extension may not be empty");
+
+  SmallString<256> FullPath;
+
+  if (!Relative)
+    FullPath.append(Opts.ShowOutputDirectory);
+
+  if (!InToplevel)
+    sys::path::append(FullPath, getCoverageDir());
+
+  SmallString<256> ParentPath = sys::path::parent_path(Path);
+  sys::path::remove_dots(ParentPath, /*remove_dot_dots=*/true);
+  sys::path::append(FullPath, sys::path::relative_path(ParentPath));
+
+  auto PathFilename = (sys::path::filename(Path) + "." + Extension).str();
+  sys::path::append(FullPath, PathFilename);
+
+  return FullPath.str();
 }
 
-void SourceCoverageView::renderIndent(raw_ostream &OS, unsigned Level) {
-  for (unsigned I = 0; I < Level; ++I)
-    OS << "  |";
+Expected<CoveragePrinter::OwnedStream>
+CoveragePrinter::createOutputStream(StringRef Path, StringRef Extension,
+                                    bool InToplevel) {
+  if (!Opts.hasOutputDirectory())
+    return OwnedStream(&outs());
+
+  std::string FullPath = getOutputPath(Path, Extension, InToplevel, false);
+
+  auto ParentDir = sys::path::parent_path(FullPath);
+  if (auto E = sys::fs::create_directories(ParentDir))
+    return errorCodeToError(E);
+
+  std::error_code E;
+  raw_ostream *RawStream = new raw_fd_ostream(FullPath, E, sys::fs::F_RW);
+  auto OS = CoveragePrinter::OwnedStream(RawStream);
+  if (E)
+    return errorCodeToError(E);
+  return std::move(OS);
 }
 
-void SourceCoverageView::renderViewDivider(unsigned Level, unsigned Length,
-                                           raw_ostream &OS) {
-  assert(Level != 0 && "Cannot render divider at top level");
-  renderIndent(OS, Level - 1);
-  OS.indent(2);
-  for (unsigned I = 0; I < Length; ++I)
-    OS << "-";
+std::unique_ptr<CoveragePrinter>
+CoveragePrinter::create(const CoverageViewOptions &Opts) {
+  switch (Opts.Format) {
+  case CoverageViewOptions::OutputFormat::Text:
+    return llvm::make_unique<CoveragePrinterText>(Opts);
+  case CoverageViewOptions::OutputFormat::HTML:
+    return llvm::make_unique<CoveragePrinterHTML>(Opts);
+  }
+  llvm_unreachable("Unknown coverage output format!");
 }
 
-/// Format a count using engineering notation with 3 significant digits.
-static std::string formatCount(uint64_t N) {
+std::string SourceCoverageView::formatCount(uint64_t N) {
   std::string Number = utostr(N);
   int Len = Number.size();
   if (Len <= 3)
@@ -94,63 +96,49 @@ static std::string formatCount(uint64_t N) {
   return Result;
 }
 
-void
-SourceCoverageView::renderLineCoverageColumn(raw_ostream &OS,
-                                             const LineCoverageInfo &Line) {
-  if (!Line.isMapped()) {
-    OS.indent(LineCoverageColumnWidth) << '|';
-    return;
-  }
-  std::string C = formatCount(Line.ExecutionCount);
-  OS.indent(LineCoverageColumnWidth - C.size());
-  colored_ostream(OS, raw_ostream::MAGENTA,
-                  Line.hasMultipleRegions() && Options.Colors)
-      << C;
-  OS << '|';
+bool SourceCoverageView::shouldRenderRegionMarkers(
+    bool LineHasMultipleRegions) const {
+  return getOptions().ShowRegionMarkers &&
+         (!getOptions().ShowLineStatsOrRegionMarkers || LineHasMultipleRegions);
 }
 
-void SourceCoverageView::renderLineNumberColumn(raw_ostream &OS,
-                                                unsigned LineNo) {
-  SmallString<32> Buffer;
-  raw_svector_ostream BufferOS(Buffer);
-  BufferOS << LineNo;
-  auto Str = BufferOS.str();
-  // Trim and align to the right
-  Str = Str.substr(0, std::min(Str.size(), (size_t)LineNumberColumnWidth));
-  OS.indent(LineNumberColumnWidth - Str.size()) << Str << '|';
+bool SourceCoverageView::hasSubViews() const {
+  return !ExpansionSubViews.empty() || !InstantiationSubViews.empty();
 }
 
-void SourceCoverageView::renderRegionMarkers(
-    raw_ostream &OS, ArrayRef<const coverage::CoverageSegment *> Segments) {
-  unsigned PrevColumn = 1;
-  for (const auto *S : Segments) {
-    if (!S->IsRegionEntry)
-      continue;
-    // Skip to the new region
-    if (S->Col > PrevColumn)
-      OS.indent(S->Col - PrevColumn);
-    PrevColumn = S->Col + 1;
-    std::string C = formatCount(S->Count);
-    PrevColumn += C.size();
-    OS << '^' << C;
+std::unique_ptr<SourceCoverageView>
+SourceCoverageView::create(StringRef SourceName, const MemoryBuffer &File,
+                           const CoverageViewOptions &Options,
+                           coverage::CoverageData &&CoverageInfo) {
+  switch (Options.Format) {
+  case CoverageViewOptions::OutputFormat::Text:
+    return llvm::make_unique<SourceCoverageViewText>(SourceName, File, Options,
+                                                     std::move(CoverageInfo));
+  case CoverageViewOptions::OutputFormat::HTML:
+    return llvm::make_unique<SourceCoverageViewHTML>(SourceName, File, Options,
+                                                     std::move(CoverageInfo));
   }
-  OS << "\n";
+  llvm_unreachable("Unknown coverage output format!");
+}
+
+void SourceCoverageView::addExpansion(
+    const coverage::CounterMappingRegion &Region,
+    std::unique_ptr<SourceCoverageView> View) {
+  ExpansionSubViews.emplace_back(Region, std::move(View));
+}
 
-  if (Options.Debug)
-    for (const auto *S : Segments)
-      errs() << "Marker at " << S->Line << ":" << S->Col << " = "
-             << formatCount(S->Count) << (S->IsRegionEntry ? "\n" : " (pop)\n");
+void SourceCoverageView::addInstantiation(
+    StringRef FunctionName, unsigned Line,
+    std::unique_ptr<SourceCoverageView> View) {
+  InstantiationSubViews.emplace_back(FunctionName, Line, std::move(View));
 }
 
-void SourceCoverageView::render(raw_ostream &OS, bool WholeFile,
-                                unsigned IndentLevel) {
-  // The width of the leading columns
-  unsigned CombinedColumnWidth =
-      (Options.ShowLineStats ? LineCoverageColumnWidth + 1 : 0) +
-      (Options.ShowLineNumbers ? LineNumberColumnWidth + 1 : 0);
-  // The width of the line that is used to divide between the view and the
-  // subviews.
-  unsigned DividerWidth = CombinedColumnWidth + 4;
+void SourceCoverageView::print(raw_ostream &OS, bool WholeFile,
+                               bool ShowSourceName, unsigned ViewDepth) {
+  if (ShowSourceName)
+    renderSourceName(OS);
+
+  renderViewHeader(OS);
 
   // We need the expansions and instantiations sorted so we can go through them
   // while we iterate lines.
@@ -186,79 +174,60 @@ void SourceCoverageView::render(raw_ostream &OS, bool WholeFile,
       LineSegments.push_back(&*NextSegment++);
 
     // Calculate a count to be for the line as a whole.
-    LineCoverageInfo LineCount;
+    LineCoverageStats LineCount;
     if (WrappedSegment && WrappedSegment->HasCount)
       LineCount.addRegionCount(WrappedSegment->Count);
     for (const auto *S : LineSegments)
       if (S->HasCount && S->IsRegionEntry)
-          LineCount.addRegionStartCount(S->Count);
+        LineCount.addRegionStartCount(S->Count);
 
-    // Render the line prefix.
-    renderIndent(OS, IndentLevel);
-    if (Options.ShowLineStats)
+    renderLinePrefix(OS, ViewDepth);
+    if (getOptions().ShowLineStats)
       renderLineCoverageColumn(OS, LineCount);
-    if (Options.ShowLineNumbers)
+    if (getOptions().ShowLineNumbers)
       renderLineNumberColumn(OS, LI.line_number());
 
     // If there are expansion subviews, we want to highlight the first one.
     unsigned ExpansionColumn = 0;
     if (NextESV != EndESV && NextESV->getLine() == LI.line_number() &&
-        Options.Colors)
+        getOptions().Colors)
       ExpansionColumn = NextESV->getStartCol();
 
     // Display the source code for the current line.
-    renderLine(OS, *LI, LI.line_number(), WrappedSegment, LineSegments,
-               ExpansionColumn);
+    renderLine(OS, {*LI, LI.line_number()}, WrappedSegment, LineSegments,
+               ExpansionColumn, ViewDepth);
 
     // Show the region markers.
-    if (Options.ShowRegionMarkers && (!Options.ShowLineStatsOrRegionMarkers ||
-                                      LineCount.hasMultipleRegions()) &&
-        !LineSegments.empty()) {
-      renderIndent(OS, IndentLevel);
-      OS.indent(CombinedColumnWidth);
-      renderRegionMarkers(OS, LineSegments);
-    }
+    if (shouldRenderRegionMarkers(LineCount.hasMultipleRegions()))
+      renderRegionMarkers(OS, LineSegments, ViewDepth);
 
     // Show the expansions and instantiations for this line.
-    unsigned NestedIndent = IndentLevel + 1;
     bool RenderedSubView = false;
     for (; NextESV != EndESV && NextESV->getLine() == LI.line_number();
          ++NextESV) {
-      renderViewDivider(NestedIndent, DividerWidth, OS);
-      OS << "\n";
+      renderViewDivider(OS, ViewDepth + 1);
+
+      // Re-render the current line and highlight the expansion range for
+      // this subview.
       if (RenderedSubView) {
-        // Re-render the current line and highlight the expansion range for
-        // this subview.
         ExpansionColumn = NextESV->getStartCol();
-        renderIndent(OS, IndentLevel);
-        OS.indent(CombinedColumnWidth + (IndentLevel == 0 ? 0 : 1));
-        renderLine(OS, *LI, LI.line_number(), WrappedSegment, LineSegments,
-                   ExpansionColumn);
-        renderViewDivider(NestedIndent, DividerWidth, OS);
-        OS << "\n";
+        renderExpansionSite(OS, {*LI, LI.line_number()}, WrappedSegment,
+                            LineSegments, ExpansionColumn, ViewDepth);
+        renderViewDivider(OS, ViewDepth + 1);
       }
-      // Render the child subview
-      if (Options.Debug)
-        errs() << "Expansion at line " << NextESV->getLine() << ", "
-               << NextESV->getStartCol() << " -> " << NextESV->getEndCol()
-               << "\n";
-      NextESV->View->render(OS, false, NestedIndent);
+
+      renderExpansionView(OS, *NextESV, ViewDepth + 1);
       RenderedSubView = true;
     }
     for (; NextISV != EndISV && NextISV->Line == LI.line_number(); ++NextISV) {
-      renderViewDivider(NestedIndent, DividerWidth, OS);
-      OS << "\n";
-      renderIndent(OS, NestedIndent);
-      OS << ' ';
-      Options.colored_ostream(OS, raw_ostream::CYAN) << NextISV->FunctionName
-                                                     << ":";
-      OS << "\n";
-      NextISV->View->render(OS, false, NestedIndent);
+      renderViewDivider(OS, ViewDepth + 1);
+      renderInstantiationView(OS, *NextISV, ViewDepth + 1);
       RenderedSubView = true;
     }
-    if (RenderedSubView) {
-      renderViewDivider(NestedIndent, DividerWidth, OS);
-      OS << "\n";
-    }
+    if (RenderedSubView)
+      renderViewDivider(OS, ViewDepth + 1);
+    renderLineSuffix(OS, ViewDepth);
   }
+
+  renderViewFooter(OS);
 }
diff --git a/tools/llvm-cov/SourceCoverageView.h b/tools/llvm-cov/SourceCoverageView.h
index 9e6fe5f350012..feef959f86bf1 100644
--- a/tools/llvm-cov/SourceCoverageView.h
+++ b/tools/llvm-cov/SourceCoverageView.h
@@ -6,16 +6,16 @@
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
-//
-// This class implements rendering for code coverage of source code.
-//
+///
+/// \file This class implements rendering for code coverage of source code.
+///
 //===----------------------------------------------------------------------===//
 
 #ifndef LLVM_COV_SOURCECOVERAGEVIEW_H
 #define LLVM_COV_SOURCECOVERAGEVIEW_H
 
 #include "CoverageViewOptions.h"
-#include "llvm/ProfileData/CoverageMapping.h"
+#include "llvm/ProfileData/Coverage/CoverageMapping.h"
 #include "llvm/Support/MemoryBuffer.h"
 #include <vector>
 
@@ -23,7 +23,7 @@ namespace llvm {
 
 class SourceCoverageView;
 
-/// \brief A view that represents a macro or include expansion
+/// \brief A view that represents a macro or include expansion.
 struct ExpansionView {
   coverage::CounterMappingRegion Region;
   std::unique_ptr<SourceCoverageView> View;
@@ -48,7 +48,7 @@ struct ExpansionView {
   }
 };
 
-/// \brief A view that represents a function instantiation
+/// \brief A view that represents a function instantiation.
 struct InstantiationView {
   StringRef FunctionName;
   unsigned Line;
@@ -73,87 +73,211 @@ struct InstantiationView {
   }
 };
 
-/// \brief A code coverage view of a specific source file.
-/// It can have embedded coverage views.
-class SourceCoverageView {
-private:
-  /// \brief Coverage information for a single line.
-  struct LineCoverageInfo {
-    uint64_t ExecutionCount;
-    unsigned RegionCount;
-    bool Mapped;
+/// \brief Coverage statistics for a single line.
+struct LineCoverageStats {
+  uint64_t ExecutionCount;
+  unsigned RegionCount;
+  bool Mapped;
+
+  LineCoverageStats() : ExecutionCount(0), RegionCount(0), Mapped(false) {}
 
-    LineCoverageInfo() : ExecutionCount(0), RegionCount(0), Mapped(false) {}
+  bool isMapped() const { return Mapped; }
 
-    bool isMapped() const { return Mapped; }
+  bool hasMultipleRegions() const { return RegionCount > 1; }
 
-    bool hasMultipleRegions() const { return RegionCount > 1; }
+  void addRegionStartCount(uint64_t Count) {
+    // The max of all region starts is the most interesting value.
+    addRegionCount(RegionCount ? std::max(ExecutionCount, Count) : Count);
+    ++RegionCount;
+  }
+
+  void addRegionCount(uint64_t Count) {
+    Mapped = true;
+    ExecutionCount = Count;
+  }
+};
 
-    void addRegionStartCount(uint64_t Count) {
-      // The max of all region starts is the most interesting value.
-      addRegionCount(RegionCount ? std::max(ExecutionCount, Count) : Count);
-      ++RegionCount;
-    }
+/// \brief A file manager that handles format-aware file creation.
+class CoveragePrinter {
+  const CoverageViewOptions &Opts;
 
-    void addRegionCount(uint64_t Count) {
-      Mapped = true;
-      ExecutionCount = Count;
-    }
+public:
+  struct StreamDestructor {
+    void operator()(raw_ostream *OS) const;
   };
 
+  using OwnedStream = std::unique_ptr<raw_ostream, StreamDestructor>;
+
+protected:
+  CoveragePrinter(const CoverageViewOptions &Opts) : Opts(Opts) {}
+
+  /// \brief Return `OutputDir/ToplevelDir/Path.Extension`. If \p InToplevel is
+  /// false, skip the ToplevelDir component. If \p Relative is false, skip the
+  /// OutputDir component.
+  std::string getOutputPath(StringRef Path, StringRef Extension,
+                            bool InToplevel, bool Relative = true);
+
+  /// \brief If directory output is enabled, create a file in that directory
+  /// at the path given by getOutputPath(). Otherwise, return stdout.
+  Expected<OwnedStream> createOutputStream(StringRef Path, StringRef Extension,
+                                           bool InToplevel);
+
+  /// \brief Return the sub-directory name for file coverage reports.
+  static StringRef getCoverageDir() { return "coverage"; }
+
+public:
+  static std::unique_ptr<CoveragePrinter>
+  create(const CoverageViewOptions &Opts);
+
+  virtual ~CoveragePrinter() {}
+
+  /// @name File Creation Interface
+  /// @{
+
+  /// \brief Create a file to print a coverage view into.
+  virtual Expected<OwnedStream> createViewFile(StringRef Path,
+                                               bool InToplevel) = 0;
+
+  /// \brief Close a file which has been used to print a coverage view.
+  virtual void closeViewFile(OwnedStream OS) = 0;
+
+  /// \brief Create an index which lists reports for the given source files.
+  virtual Error createIndexFile(ArrayRef<StringRef> SourceFiles) = 0;
+
+  /// @}
+};
+
+/// \brief A code coverage view of a source file or function.
+///
+/// A source coverage view and its nested sub-views form a file-oriented
+/// representation of code coverage data. This view can be printed out by a
+/// renderer which implements the Rendering Interface.
+class SourceCoverageView {
+  /// A function or file name.
+  StringRef SourceName;
+
+  /// A memory buffer backing the source on display.
   const MemoryBuffer &File;
+
+  /// Various options to guide the coverage renderer.
   const CoverageViewOptions &Options;
+
+  /// Complete coverage information about the source on display.
   coverage::CoverageData CoverageInfo;
+
+  /// A container for all expansions (e.g macros) in the source on display.
   std::vector<ExpansionView> ExpansionSubViews;
+
+  /// A container for all instantiations (e.g template functions) in the source
+  /// on display.
   std::vector<InstantiationView> InstantiationSubViews;
 
-  /// \brief Render a source line with highlighting.
-  void renderLine(raw_ostream &OS, StringRef Line, int64_t LineNumber,
-                  const coverage::CoverageSegment *WrappedSegment,
-                  ArrayRef<const coverage::CoverageSegment *> Segments,
-                  unsigned ExpansionCol);
+protected:
+  struct LineRef {
+    StringRef Line;
+    int64_t LineNo;
+
+    LineRef(StringRef Line, int64_t LineNo) : Line(Line), LineNo(LineNo) {}
+  };
+
+  using CoverageSegmentArray = ArrayRef<const coverage::CoverageSegment *>;
+
+  /// @name Rendering Interface
+  /// @{
 
-  void renderIndent(raw_ostream &OS, unsigned Level);
+  /// \brief Render a header for the view.
+  virtual void renderViewHeader(raw_ostream &OS) = 0;
 
-  void renderViewDivider(unsigned Offset, unsigned Length, raw_ostream &OS);
+  /// \brief Render a footer for the view.
+  virtual void renderViewFooter(raw_ostream &OS) = 0;
+
+  /// \brief Render the source name for the view.
+  virtual void renderSourceName(raw_ostream &OS) = 0;
+
+  /// \brief Render the line prefix at the given \p ViewDepth.
+  virtual void renderLinePrefix(raw_ostream &OS, unsigned ViewDepth) = 0;
+
+  /// \brief Render the line suffix at the given \p ViewDepth.
+  virtual void renderLineSuffix(raw_ostream &OS, unsigned ViewDepth) = 0;
+
+  /// \brief Render a view divider at the given \p ViewDepth.
+  virtual void renderViewDivider(raw_ostream &OS, unsigned ViewDepth) = 0;
+
+  /// \brief Render a source line with highlighting.
+  virtual void renderLine(raw_ostream &OS, LineRef L,
+                          const coverage::CoverageSegment *WrappedSegment,
+                          CoverageSegmentArray Segments, unsigned ExpansionCol,
+                          unsigned ViewDepth) = 0;
 
   /// \brief Render the line's execution count column.
-  void renderLineCoverageColumn(raw_ostream &OS, const LineCoverageInfo &Line);
+  virtual void renderLineCoverageColumn(raw_ostream &OS,
+                                        const LineCoverageStats &Line) = 0;
 
   /// \brief Render the line number column.
-  void renderLineNumberColumn(raw_ostream &OS, unsigned LineNo);
+  virtual void renderLineNumberColumn(raw_ostream &OS, unsigned LineNo) = 0;
 
   /// \brief Render all the region's execution counts on a line.
-  void
-  renderRegionMarkers(raw_ostream &OS,
-                      ArrayRef<const coverage::CoverageSegment *> Segments);
+  virtual void renderRegionMarkers(raw_ostream &OS,
+                                   CoverageSegmentArray Segments,
+                                   unsigned ViewDepth) = 0;
 
-  static const unsigned LineCoverageColumnWidth = 7;
-  static const unsigned LineNumberColumnWidth = 5;
+  /// \brief Render the site of an expansion.
+  virtual void
+  renderExpansionSite(raw_ostream &OS, LineRef L,
+                      const coverage::CoverageSegment *WrappedSegment,
+                      CoverageSegmentArray Segments, unsigned ExpansionCol,
+                      unsigned ViewDepth) = 0;
 
-public:
-  SourceCoverageView(const MemoryBuffer &File,
+  /// \brief Render an expansion view and any nested views.
+  virtual void renderExpansionView(raw_ostream &OS, ExpansionView &ESV,
+                                   unsigned ViewDepth) = 0;
+
+  /// \brief Render an instantiation view and any nested views.
+  virtual void renderInstantiationView(raw_ostream &OS, InstantiationView &ISV,
+                                       unsigned ViewDepth) = 0;
+
+  /// @}
+
+  /// \brief Format a count using engineering notation with 3 significant
+  /// digits.
+  static std::string formatCount(uint64_t N);
+
+  /// \brief Check if region marker output is expected for a line.
+  bool shouldRenderRegionMarkers(bool LineHasMultipleRegions) const;
+
+  /// \brief Check if there are any sub-views attached to this view.
+  bool hasSubViews() const;
+
+  SourceCoverageView(StringRef SourceName, const MemoryBuffer &File,
                      const CoverageViewOptions &Options,
                      coverage::CoverageData &&CoverageInfo)
-      : File(File), Options(Options), CoverageInfo(std::move(CoverageInfo)) {}
+      : SourceName(SourceName), File(File), Options(Options),
+        CoverageInfo(std::move(CoverageInfo)) {}
+
+public:
+  static std::unique_ptr<SourceCoverageView>
+  create(StringRef SourceName, const MemoryBuffer &File,
+         const CoverageViewOptions &Options,
+         coverage::CoverageData &&CoverageInfo);
+
+  virtual ~SourceCoverageView() {}
+
+  StringRef getSourceName() const { return SourceName; }
 
   const CoverageViewOptions &getOptions() const { return Options; }
 
   /// \brief Add an expansion subview to this view.
   void addExpansion(const coverage::CounterMappingRegion &Region,
-                    std::unique_ptr<SourceCoverageView> View) {
-    ExpansionSubViews.emplace_back(Region, std::move(View));
-  }
+                    std::unique_ptr<SourceCoverageView> View);
 
   /// \brief Add a function instantiation subview to this view.
   void addInstantiation(StringRef FunctionName, unsigned Line,
-                        std::unique_ptr<SourceCoverageView> View) {
-    InstantiationSubViews.emplace_back(FunctionName, Line, std::move(View));
-  }
+                        std::unique_ptr<SourceCoverageView> View);
 
-  /// \brief Print the code coverage information for a specific
-  /// portion of a source file to the output stream.
-  void render(raw_ostream &OS, bool WholeFile, unsigned IndentLevel = 0);
+  /// \brief Print the code coverage information for a specific portion of a
+  /// source file to the output stream.
+  void print(raw_ostream &OS, bool WholeFile, bool ShowSourceName,
+             unsigned ViewDepth = 0);
 };
 
 } // namespace llvm
diff --git a/tools/llvm-cov/SourceCoverageViewHTML.cpp b/tools/llvm-cov/SourceCoverageViewHTML.cpp
new file mode 100644
index 0000000000000..81963e5c54474
--- /dev/null
+++ b/tools/llvm-cov/SourceCoverageViewHTML.cpp
@@ -0,0 +1,436 @@
+//===- SourceCoverageViewHTML.cpp - A html code coverage view -------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file This file implements the html coverage renderer.
+///
+//===----------------------------------------------------------------------===//
+
+#include "SourceCoverageViewHTML.h"
+#include "llvm/ADT/Optional.h"
+#include "llvm/ADT/SmallString.h"
+#include "llvm/ADT/StringExtras.h"
+#include "llvm/Support/Path.h"
+
+using namespace llvm;
+
+namespace {
+
+const char *BeginHeader =
+  "<head>"
+    "<meta name='viewport' content='width=device-width,initial-scale=1'>"
+    "<meta charset='UTF-8'>";
+
+const char *CSSForCoverage =
+  "<style>"
+R"(
+
+.red {
+  background-color: #FFD0D0;
+}
+.cyan {
+  background-color: cyan;
+}
+.black {
+  background-color: black;
+  color: white;
+}
+.green {
+  background-color: #98FFA6;
+  color: white;
+}
+.magenta {
+  background-color: #F998FF;
+  color: white;
+}
+body {
+  font-family: -apple-system, sans-serif;
+}
+pre {
+  margin-top: 0px !important;
+  margin-bottom: 0px !important;
+}
+.source-name-title {
+  padding: 5px 10px;
+  border-bottom: 1px solid #dbdbdb;
+  background-color: #eee;
+}
+.centered {
+  display: table;
+  margin-left: auto;
+  margin-right: auto;
+  border: 1px solid #dbdbdb;
+  border-radius: 3px;
+}
+.expansion-view {
+  background-color: rgba(0, 0, 0, 0);
+  margin-left: 0px;
+  margin-top: 5px;
+  margin-right: 5px;
+  margin-bottom: 5px;
+  border: 1px solid #dbdbdb;
+  border-radius: 3px;
+}
+table {
+  border-collapse: collapse;
+}
+.line-number {
+  text-align: right;
+  color: #aaa;
+}
+.covered-line {
+  text-align: right;
+  color: #0080ff;
+}
+.uncovered-line {
+  text-align: right;
+  color: #ff3300;
+}
+.tooltip {
+  position: relative;
+  display: inline;
+  background-color: #b3e6ff;
+  text-decoration: none;
+}
+.tooltip span.tooltip-content {
+  position: absolute;
+  width: 100px;
+  margin-left: -50px;
+  color: #FFFFFF;
+  background: #000000;
+  height: 30px;
+  line-height: 30px;
+  text-align: center;
+  visibility: hidden;
+  border-radius: 6px;
+}
+.tooltip span.tooltip-content:after {
+  content: '';
+  position: absolute;
+  top: 100%;
+  left: 50%;
+  margin-left: -8px;
+  width: 0; height: 0;
+  border-top: 8px solid #000000;
+  border-right: 8px solid transparent;
+  border-left: 8px solid transparent;
+}
+:hover.tooltip span.tooltip-content {
+  visibility: visible;
+  opacity: 0.8;
+  bottom: 30px;
+  left: 50%;
+  z-index: 999;
+}
+th, td {
+  vertical-align: top;
+  padding: 2px 5px;
+  border-collapse: collapse;
+  border-right: solid 1px #eee;
+  border-left: solid 1px #eee;
+}
+td:first-child {
+  border-left: none;
+}
+td:last-child {
+  border-right: none;
+}
+
+)"
+  "</style>";
+
+const char *EndHeader = "</head>";
+
+const char *BeginCenteredDiv = "<div class='centered'>";
+
+const char *EndCenteredDiv = "</div>";
+
+const char *BeginSourceNameDiv = "<div class='source-name-title'>";
+
+const char *EndSourceNameDiv = "</div>";
+
+const char *BeginCodeTD = "<td class='code'>";
+
+const char *EndCodeTD = "</td>";
+
+const char *BeginPre = "<pre>";
+
+const char *EndPre = "</pre>";
+
+const char *BeginExpansionDiv = "<div class='expansion-view'>";
+
+const char *EndExpansionDiv = "</div>";
+
+const char *BeginTable = "<table>";
+
+const char *EndTable = "</table>";
+
+void emitPrelude(raw_ostream &OS) {
+  OS << "<!doctype html>"
+        "<html>"
+     << BeginHeader << CSSForCoverage << EndHeader << "<body>"
+     << BeginCenteredDiv;
+}
+
+void emitEpilog(raw_ostream &OS) {
+  OS << EndCenteredDiv << "</body>"
+                          "</html>";
+}
+
+// Return a string with the special characters in \p Str escaped.
+std::string escape(StringRef Str) {
+  std::string Result;
+  for (char C : Str) {
+    if (C == '&')
+      Result += "&amp;";
+    else if (C == '<')
+      Result += "&lt;";
+    else if (C == '>')
+      Result += "&gt;";
+    else if (C == '\"')
+      Result += "&quot;";
+    else
+      Result += C;
+  }
+  return Result;
+}
+
+// Create a \p Name tag around \p Str, and optionally set its \p ClassName.
+std::string tag(const std::string &Name, const std::string &Str,
+                const std::string &ClassName = "") {
+  std::string Tag = "<" + Name;
+  if (ClassName != "")
+    Tag += " class='" + ClassName + "'";
+  return Tag + ">" + Str + "</" + Name + ">";
+}
+
+// Create an anchor to \p Link with the label \p Str.
+std::string a(const std::string &Link, const std::string &Str) {
+  return "<a href='" + Link + "'>" + Str + "</a>";
+}
+
+} // anonymous namespace
+
+Expected<CoveragePrinter::OwnedStream>
+CoveragePrinterHTML::createViewFile(StringRef Path, bool InToplevel) {
+  auto OSOrErr = createOutputStream(Path, "html", InToplevel);
+  if (!OSOrErr)
+    return OSOrErr;
+
+  OwnedStream OS = std::move(OSOrErr.get());
+  emitPrelude(*OS.get());
+  return std::move(OS);
+}
+
+void CoveragePrinterHTML::closeViewFile(OwnedStream OS) {
+  emitEpilog(*OS.get());
+}
+
+Error CoveragePrinterHTML::createIndexFile(ArrayRef<StringRef> SourceFiles) {
+  auto OSOrErr = createOutputStream("index", "html", /*InToplevel=*/true);
+  if (Error E = OSOrErr.takeError())
+    return E;
+  auto OS = std::move(OSOrErr.get());
+  raw_ostream &OSRef = *OS.get();
+
+  // Emit a table containing links to reports for each file in the covmapping.
+  emitPrelude(OSRef);
+  OSRef << BeginSourceNameDiv << "Index" << EndSourceNameDiv;
+  OSRef << BeginTable;
+  for (StringRef SF : SourceFiles) {
+    std::string LinkText = escape(sys::path::relative_path(SF));
+    std::string LinkTarget =
+        escape(getOutputPath(SF, "html", /*InToplevel=*/false));
+    OSRef << tag("tr", tag("td", tag("pre", a(LinkTarget, LinkText), "code")));
+  }
+  OSRef << EndTable;
+  emitEpilog(OSRef);
+
+  return Error::success();
+}
+
+void SourceCoverageViewHTML::renderViewHeader(raw_ostream &OS) {
+  OS << BeginTable;
+}
+
+void SourceCoverageViewHTML::renderViewFooter(raw_ostream &OS) {
+  OS << EndTable;
+}
+
+void SourceCoverageViewHTML::renderSourceName(raw_ostream &OS) {
+  OS << BeginSourceNameDiv << tag("pre", escape(getSourceName()))
+     << EndSourceNameDiv;
+}
+
+void SourceCoverageViewHTML::renderLinePrefix(raw_ostream &OS, unsigned) {
+  OS << "<tr>";
+}
+
+void SourceCoverageViewHTML::renderLineSuffix(raw_ostream &OS, unsigned) {
+  // If this view has sub-views, renderLine() cannot close the view's cell.
+  // Take care of it here, after all sub-views have been rendered.
+  if (hasSubViews())
+    OS << EndCodeTD;
+  OS << "</tr>";
+}
+
+void SourceCoverageViewHTML::renderViewDivider(raw_ostream &, unsigned) {
+  // The table-based output makes view dividers unnecessary.
+}
+
+void SourceCoverageViewHTML::renderLine(
+    raw_ostream &OS, LineRef L, const coverage::CoverageSegment *WrappedSegment,
+    CoverageSegmentArray Segments, unsigned ExpansionCol, unsigned) {
+  StringRef Line = L.Line;
+
+  // Steps for handling text-escaping, highlighting, and tooltip creation:
+  //
+  // 1. Split the line into N+1 snippets, where N = |Segments|. The first
+  //    snippet starts from Col=1 and ends at the start of the first segment.
+  //    The last snippet starts at the last mapped column in the line and ends
+  //    at the end of the line. Both are required but may be empty.
+
+  SmallVector<std::string, 8> Snippets;
+
+  unsigned LCol = 1;
+  auto Snip = [&](unsigned Start, unsigned Len) {
+    assert(Start + Len <= Line.size() && "Snippet extends past the EOL");
+    Snippets.push_back(Line.substr(Start, Len));
+    LCol += Len;
+  };
+
+  Snip(LCol - 1, Segments.empty() ? 0 : (Segments.front()->Col - 1));
+
+  for (unsigned I = 1, E = Segments.size(); I < E; ++I) {
+    assert(LCol == Segments[I - 1]->Col && "Snippet start position is wrong");
+    Snip(LCol - 1, Segments[I]->Col - LCol);
+  }
+
+  // |Line| + 1 is needed to avoid underflow when, e.g |Line| = 0 and LCol = 1.
+  Snip(LCol - 1, Line.size() + 1 - LCol);
+  assert(LCol == Line.size() + 1 && "Final snippet doesn't reach the EOL");
+
+  // 2. Escape all of the snippets.
+
+  for (unsigned I = 0, E = Snippets.size(); I < E; ++I)
+    Snippets[I] = escape(Snippets[I]);
+
+  // 3. Use \p WrappedSegment to set the highlight for snippets 0 and 1. Use
+  //    segment 1 to set the highlight for snippet 2, segment 2 to set the
+  //    highlight for snippet 3, and so on.
+
+  Optional<std::string> Color;
+  auto Highlight = [&](const std::string &Snippet) {
+    return tag("span", Snippet, Color.getValue());
+  };
+
+  auto CheckIfUncovered = [](const coverage::CoverageSegment *S) {
+    return S && S->HasCount && S->Count == 0;
+  };
+
+  if (CheckIfUncovered(WrappedSegment) ||
+      CheckIfUncovered(Segments.empty() ? nullptr : Segments.front())) {
+    Color = "red";
+    Snippets[0] = Highlight(Snippets[0]);
+    Snippets[1] = Highlight(Snippets[1]);
+  }
+
+  for (unsigned I = 1, E = Segments.size(); I < E; ++I) {
+    const auto *CurSeg = Segments[I];
+    if (CurSeg->Col == ExpansionCol)
+      Color = "cyan";
+    else if (CheckIfUncovered(CurSeg))
+      Color = "red";
+    else
+      Color = None;
+
+    if (Color.hasValue())
+      Snippets[I + 1] = Highlight(Snippets[I + 1]);
+  }
+
+  // 4. Snippets[1:N+1] correspond to \p Segments[0:N]: use these to generate
+  //    sub-line region count tooltips if needed.
+
+  bool HasMultipleRegions = [&] {
+    unsigned RegionCount = 0;
+    for (const auto *S : Segments)
+      if (S->HasCount && S->IsRegionEntry)
+        if (++RegionCount > 1)
+          return true;
+    return false;
+  }();
+
+  if (shouldRenderRegionMarkers(HasMultipleRegions)) {
+    for (unsigned I = 0, E = Segments.size(); I < E; ++I) {
+      const auto *CurSeg = Segments[I];
+      if (!CurSeg->IsRegionEntry || !CurSeg->HasCount)
+        continue;
+
+      Snippets[I + 1] =
+          tag("div", Snippets[I + 1] + tag("span", formatCount(CurSeg->Count),
+                                          "tooltip-content"),
+              "tooltip");
+    }
+  }
+
+  OS << BeginCodeTD;
+  OS << BeginPre;
+  for (const auto &Snippet : Snippets)
+    OS << Snippet;
+  OS << EndPre;
+
+  // If there are no sub-views left to attach to this cell, end the cell.
+  // Otherwise, end it after the sub-views are rendered (renderLineSuffix()).
+  if (!hasSubViews())
+    OS << EndCodeTD;
+}
+
+void SourceCoverageViewHTML::renderLineCoverageColumn(
+    raw_ostream &OS, const LineCoverageStats &Line) {
+  std::string Count = "";
+  if (Line.isMapped())
+    Count = tag("pre", formatCount(Line.ExecutionCount));
+  std::string CoverageClass =
+      (Line.ExecutionCount > 0) ? "covered-line" : "uncovered-line";
+  OS << tag("td", Count, CoverageClass);
+}
+
+void SourceCoverageViewHTML::renderLineNumberColumn(raw_ostream &OS,
+                                                    unsigned LineNo) {
+  OS << tag("td", tag("pre", utostr(uint64_t(LineNo))), "line-number");
+}
+
+void SourceCoverageViewHTML::renderRegionMarkers(raw_ostream &,
+                                                 CoverageSegmentArray,
+                                                 unsigned) {
+  // Region markers are rendered in-line using tooltips.
+}
+
+void SourceCoverageViewHTML::renderExpansionSite(
+    raw_ostream &OS, LineRef L, const coverage::CoverageSegment *WrappedSegment,
+    CoverageSegmentArray Segments, unsigned ExpansionCol, unsigned ViewDepth) {
+  // Render the line containing the expansion site. No extra formatting needed.
+  renderLine(OS, L, WrappedSegment, Segments, ExpansionCol, ViewDepth);
+}
+
+void SourceCoverageViewHTML::renderExpansionView(raw_ostream &OS,
+                                                 ExpansionView &ESV,
+                                                 unsigned ViewDepth) {
+  OS << BeginExpansionDiv;
+  ESV.View->print(OS, /*WholeFile=*/false, /*ShowSourceName=*/false,
+                  ViewDepth + 1);
+  OS << EndExpansionDiv;
+}
+
+void SourceCoverageViewHTML::renderInstantiationView(raw_ostream &OS,
+                                                     InstantiationView &ISV,
+                                                     unsigned ViewDepth) {
+  OS << BeginExpansionDiv;
+  ISV.View->print(OS, /*WholeFile=*/false, /*ShowSourceName=*/true, ViewDepth);
+  OS << EndExpansionDiv;
+}
diff --git a/tools/llvm-cov/SourceCoverageViewHTML.h b/tools/llvm-cov/SourceCoverageViewHTML.h
new file mode 100644
index 0000000000000..50ecf2bf89970
--- /dev/null
+++ b/tools/llvm-cov/SourceCoverageViewHTML.h
@@ -0,0 +1,83 @@
+//===- SourceCoverageViewHTML.h - A html code coverage view ---------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file This file defines the interface to the html coverage renderer.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_COV_SOURCECOVERAGEVIEWHTML_H
+#define LLVM_COV_SOURCECOVERAGEVIEWHTML_H
+
+#include "SourceCoverageView.h"
+
+namespace llvm {
+
+/// \brief A coverage printer for html output.
+class CoveragePrinterHTML : public CoveragePrinter {
+public:
+  Expected<OwnedStream> createViewFile(StringRef Path,
+                                       bool InToplevel) override;
+
+  void closeViewFile(OwnedStream OS) override;
+
+  Error createIndexFile(ArrayRef<StringRef> SourceFiles) override;
+
+  CoveragePrinterHTML(const CoverageViewOptions &Opts)
+      : CoveragePrinter(Opts) {}
+};
+
+/// \brief A code coverage view which supports html-based rendering.
+class SourceCoverageViewHTML : public SourceCoverageView {
+  void renderViewHeader(raw_ostream &OS) override;
+
+  void renderViewFooter(raw_ostream &OS) override;
+
+  void renderSourceName(raw_ostream &OS) override;
+
+  void renderLinePrefix(raw_ostream &OS, unsigned ViewDepth) override;
+
+  void renderLineSuffix(raw_ostream &OS, unsigned ViewDepth) override;
+
+  void renderViewDivider(raw_ostream &OS, unsigned ViewDepth) override;
+
+  void renderLine(raw_ostream &OS, LineRef L,
+                  const coverage::CoverageSegment *WrappedSegment,
+                  CoverageSegmentArray Segments, unsigned ExpansionCol,
+                  unsigned ViewDepth) override;
+
+  void renderExpansionSite(raw_ostream &OS, LineRef L,
+                           const coverage::CoverageSegment *WrappedSegment,
+                           CoverageSegmentArray Segments, unsigned ExpansionCol,
+                           unsigned ViewDepth) override;
+
+  void renderExpansionView(raw_ostream &OS, ExpansionView &ESV,
+                           unsigned ViewDepth) override;
+
+  void renderInstantiationView(raw_ostream &OS, InstantiationView &ISV,
+                               unsigned ViewDepth) override;
+
+  void renderLineCoverageColumn(raw_ostream &OS,
+                                const LineCoverageStats &Line) override;
+
+  void renderLineNumberColumn(raw_ostream &OS, unsigned LineNo) override;
+
+  void renderRegionMarkers(raw_ostream &OS, CoverageSegmentArray Segments,
+                           unsigned ViewDepth) override;
+
+public:
+  SourceCoverageViewHTML(StringRef SourceName, const MemoryBuffer &File,
+                         const CoverageViewOptions &Options,
+                         coverage::CoverageData &&CoverageInfo)
+      : SourceCoverageView(SourceName, File, Options, std::move(CoverageInfo)) {
+  }
+};
+
+} // namespace llvm
+
+#endif // LLVM_COV_SOURCECOVERAGEVIEWHTML_H
diff --git a/tools/llvm-cov/SourceCoverageViewText.cpp b/tools/llvm-cov/SourceCoverageViewText.cpp
new file mode 100644
index 0000000000000..ae9d6daed08f7
--- /dev/null
+++ b/tools/llvm-cov/SourceCoverageViewText.cpp
@@ -0,0 +1,213 @@
+//===- SourceCoverageViewText.cpp - A text-based code coverage view -------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file This file implements the text-based coverage renderer.
+///
+//===----------------------------------------------------------------------===//
+
+#include "SourceCoverageViewText.h"
+#include "llvm/ADT/Optional.h"
+#include "llvm/ADT/SmallString.h"
+#include "llvm/ADT/StringExtras.h"
+
+using namespace llvm;
+
+Expected<CoveragePrinter::OwnedStream>
+CoveragePrinterText::createViewFile(StringRef Path, bool InToplevel) {
+  return createOutputStream(Path, "txt", InToplevel);
+}
+
+void CoveragePrinterText::closeViewFile(OwnedStream OS) {
+  OS->operator<<('\n');
+}
+
+Error CoveragePrinterText::createIndexFile(ArrayRef<StringRef> SourceFiles) {
+  auto OSOrErr = createOutputStream("index", "txt", /*InToplevel=*/true);
+  if (Error E = OSOrErr.takeError())
+    return E;
+  auto OS = std::move(OSOrErr.get());
+  raw_ostream &OSRef = *OS.get();
+
+  for (StringRef SF : SourceFiles)
+    OSRef << getOutputPath(SF, "txt", /*InToplevel=*/false) << '\n';
+
+  return Error::success();
+}
+
+namespace {
+
+static const unsigned LineCoverageColumnWidth = 7;
+static const unsigned LineNumberColumnWidth = 5;
+
+/// \brief Get the width of the leading columns.
+unsigned getCombinedColumnWidth(const CoverageViewOptions &Opts) {
+  return (Opts.ShowLineStats ? LineCoverageColumnWidth + 1 : 0) +
+         (Opts.ShowLineNumbers ? LineNumberColumnWidth + 1 : 0);
+}
+
+/// \brief The width of the line that is used to divide between the view and
+/// the subviews.
+unsigned getDividerWidth(const CoverageViewOptions &Opts) {
+  return getCombinedColumnWidth(Opts) + 4;
+}
+
+} // anonymous namespace
+
+void SourceCoverageViewText::renderViewHeader(raw_ostream &) {}
+
+void SourceCoverageViewText::renderViewFooter(raw_ostream &) {}
+
+void SourceCoverageViewText::renderSourceName(raw_ostream &OS) {
+  getOptions().colored_ostream(OS, raw_ostream::CYAN) << getSourceName()
+                                                      << ":\n";
+}
+
+void SourceCoverageViewText::renderLinePrefix(raw_ostream &OS,
+                                              unsigned ViewDepth) {
+  for (unsigned I = 0; I < ViewDepth; ++I)
+    OS << "  |";
+}
+
+void SourceCoverageViewText::renderLineSuffix(raw_ostream &, unsigned) {}
+
+void SourceCoverageViewText::renderViewDivider(raw_ostream &OS,
+                                               unsigned ViewDepth) {
+  assert(ViewDepth != 0 && "Cannot render divider at top level");
+  renderLinePrefix(OS, ViewDepth - 1);
+  OS.indent(2);
+  unsigned Length = getDividerWidth(getOptions());
+  for (unsigned I = 0; I < Length; ++I)
+    OS << '-';
+  OS << '\n';
+}
+
+void SourceCoverageViewText::renderLine(
+    raw_ostream &OS, LineRef L,
+    const coverage::CoverageSegment *WrappedSegment,
+    CoverageSegmentArray Segments, unsigned ExpansionCol, unsigned ViewDepth) {
+  StringRef Line = L.Line;
+  unsigned LineNumber = L.LineNo;
+
+  Optional<raw_ostream::Colors> Highlight;
+  SmallVector<std::pair<unsigned, unsigned>, 2> HighlightedRanges;
+
+  // The first segment overlaps from a previous line, so we treat it specially.
+  if (WrappedSegment && WrappedSegment->HasCount && WrappedSegment->Count == 0)
+    Highlight = raw_ostream::RED;
+
+  // Output each segment of the line, possibly highlighted.
+  unsigned Col = 1;
+  for (const auto *S : Segments) {
+    unsigned End = std::min(S->Col, static_cast<unsigned>(Line.size()) + 1);
+    colored_ostream(OS, Highlight ? *Highlight : raw_ostream::SAVEDCOLOR,
+                    getOptions().Colors && Highlight, /*Bold=*/false,
+                    /*BG=*/true)
+        << Line.substr(Col - 1, End - Col);
+    if (getOptions().Debug && Highlight)
+      HighlightedRanges.push_back(std::make_pair(Col, End));
+    Col = End;
+    if (Col == ExpansionCol)
+      Highlight = raw_ostream::CYAN;
+    else if (S->HasCount && S->Count == 0)
+      Highlight = raw_ostream::RED;
+    else
+      Highlight = None;
+  }
+
+  // Show the rest of the line.
+  colored_ostream(OS, Highlight ? *Highlight : raw_ostream::SAVEDCOLOR,
+                  getOptions().Colors && Highlight, /*Bold=*/false, /*BG=*/true)
+      << Line.substr(Col - 1, Line.size() - Col + 1);
+  OS << '\n';
+
+  if (getOptions().Debug) {
+    for (const auto &Range : HighlightedRanges)
+      errs() << "Highlighted line " << LineNumber << ", " << Range.first
+             << " -> " << Range.second << '\n';
+    if (Highlight)
+      errs() << "Highlighted line " << LineNumber << ", " << Col << " -> ?\n";
+  }
+}
+
+void SourceCoverageViewText::renderLineCoverageColumn(
+    raw_ostream &OS, const LineCoverageStats &Line) {
+  if (!Line.isMapped()) {
+    OS.indent(LineCoverageColumnWidth) << '|';
+    return;
+  }
+  std::string C = formatCount(Line.ExecutionCount);
+  OS.indent(LineCoverageColumnWidth - C.size());
+  colored_ostream(OS, raw_ostream::MAGENTA,
+                  Line.hasMultipleRegions() && getOptions().Colors)
+      << C;
+  OS << '|';
+}
+
+void SourceCoverageViewText::renderLineNumberColumn(raw_ostream &OS,
+                                                    unsigned LineNo) {
+  SmallString<32> Buffer;
+  raw_svector_ostream BufferOS(Buffer);
+  BufferOS << LineNo;
+  auto Str = BufferOS.str();
+  // Trim and align to the right.
+  Str = Str.substr(0, std::min(Str.size(), (size_t)LineNumberColumnWidth));
+  OS.indent(LineNumberColumnWidth - Str.size()) << Str << '|';
+}
+
+void SourceCoverageViewText::renderRegionMarkers(
+    raw_ostream &OS, CoverageSegmentArray Segments, unsigned ViewDepth) {
+  renderLinePrefix(OS, ViewDepth);
+  OS.indent(getCombinedColumnWidth(getOptions()));
+
+  unsigned PrevColumn = 1;
+  for (const auto *S : Segments) {
+    if (!S->IsRegionEntry)
+      continue;
+    // Skip to the new region.
+    if (S->Col > PrevColumn)
+      OS.indent(S->Col - PrevColumn);
+    PrevColumn = S->Col + 1;
+    std::string C = formatCount(S->Count);
+    PrevColumn += C.size();
+    OS << '^' << C;
+  }
+  OS << '\n';
+
+  if (getOptions().Debug)
+    for (const auto *S : Segments)
+      errs() << "Marker at " << S->Line << ":" << S->Col << " = "
+             << formatCount(S->Count) << (S->IsRegionEntry ? "\n" : " (pop)\n");
+}
+
+void SourceCoverageViewText::renderExpansionSite(
+    raw_ostream &OS, LineRef L, const coverage::CoverageSegment *WrappedSegment,
+    CoverageSegmentArray Segments, unsigned ExpansionCol, unsigned ViewDepth) {
+  renderLinePrefix(OS, ViewDepth);
+  OS.indent(getCombinedColumnWidth(getOptions()) + (ViewDepth == 0 ? 0 : 1));
+  renderLine(OS, L, WrappedSegment, Segments, ExpansionCol, ViewDepth);
+}
+
+void SourceCoverageViewText::renderExpansionView(raw_ostream &OS,
+                                                 ExpansionView &ESV,
+                                                 unsigned ViewDepth) {
+  // Render the child subview.
+  if (getOptions().Debug)
+    errs() << "Expansion at line " << ESV.getLine() << ", " << ESV.getStartCol()
+           << " -> " << ESV.getEndCol() << '\n';
+  ESV.View->print(OS, /*WholeFile=*/false, /*ShowSourceName=*/false,
+                  ViewDepth + 1);
+}
+
+void SourceCoverageViewText::renderInstantiationView(raw_ostream &OS,
+                                                     InstantiationView &ISV,
+                                                     unsigned ViewDepth) {
+  renderLinePrefix(OS, ViewDepth);
+  OS << ' ';
+  ISV.View->print(OS, /*WholeFile=*/false, /*ShowSourceName=*/true, ViewDepth);
+}
diff --git a/tools/llvm-cov/SourceCoverageViewText.h b/tools/llvm-cov/SourceCoverageViewText.h
new file mode 100644
index 0000000000000..b2331247b37b7
--- /dev/null
+++ b/tools/llvm-cov/SourceCoverageViewText.h
@@ -0,0 +1,83 @@
+//===- SourceCoverageViewText.h - A text-based code coverage view ---------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file This file defines the interface to the text-based coverage renderer.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_COV_SOURCECOVERAGEVIEWTEXT_H
+#define LLVM_COV_SOURCECOVERAGEVIEWTEXT_H
+
+#include "SourceCoverageView.h"
+
+namespace llvm {
+
+/// \brief A coverage printer for text output.
+class CoveragePrinterText : public CoveragePrinter {
+public:
+  Expected<OwnedStream> createViewFile(StringRef Path,
+                                       bool InToplevel) override;
+
+  void closeViewFile(OwnedStream OS) override;
+
+  Error createIndexFile(ArrayRef<StringRef> SourceFiles) override;
+
+  CoveragePrinterText(const CoverageViewOptions &Opts)
+      : CoveragePrinter(Opts) {}
+};
+
+/// \brief A code coverage view which supports text-based rendering.
+class SourceCoverageViewText : public SourceCoverageView {
+  void renderViewHeader(raw_ostream &OS) override;
+
+  void renderViewFooter(raw_ostream &OS) override;
+
+  void renderSourceName(raw_ostream &OS) override;
+
+  void renderLinePrefix(raw_ostream &OS, unsigned ViewDepth) override;
+
+  void renderLineSuffix(raw_ostream &OS, unsigned ViewDepth) override;
+
+  void renderViewDivider(raw_ostream &OS, unsigned ViewDepth) override;
+
+  void renderLine(raw_ostream &OS, LineRef L,
+                  const coverage::CoverageSegment *WrappedSegment,
+                  CoverageSegmentArray Segments, unsigned ExpansionCol,
+                  unsigned ViewDepth) override;
+
+  void renderExpansionSite(raw_ostream &OS, LineRef L,
+                           const coverage::CoverageSegment *WrappedSegment,
+                           CoverageSegmentArray Segments, unsigned ExpansionCol,
+                           unsigned ViewDepth) override;
+
+  void renderExpansionView(raw_ostream &OS, ExpansionView &ESV,
+                           unsigned ViewDepth) override;
+
+  void renderInstantiationView(raw_ostream &OS, InstantiationView &ISV,
+                               unsigned ViewDepth) override;
+
+  void renderLineCoverageColumn(raw_ostream &OS,
+                                const LineCoverageStats &Line) override;
+
+  void renderLineNumberColumn(raw_ostream &OS, unsigned LineNo) override;
+
+  void renderRegionMarkers(raw_ostream &OS, CoverageSegmentArray Segments,
+                           unsigned ViewDepth) override;
+
+public:
+  SourceCoverageViewText(StringRef SourceName, const MemoryBuffer &File,
+                         const CoverageViewOptions &Options,
+                         coverage::CoverageData &&CoverageInfo)
+      : SourceCoverageView(SourceName, File, Options, std::move(CoverageInfo)) {
+  }
+};
+
+} // namespace llvm
+
+#endif // LLVM_COV_SOURCECOVERAGEVIEWTEXT_H
diff --git a/tools/llvm-cov/TestingSupport.cpp b/tools/llvm-cov/TestingSupport.cpp
index 6959897482ca2..72768f4fd583f 100644
--- a/tools/llvm-cov/TestingSupport.cpp
+++ b/tools/llvm-cov/TestingSupport.cpp
@@ -8,11 +8,9 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/Object/ObjectFile.h"
+#include "llvm/ProfileData/InstrProf.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/LEB128.h"
-#include "llvm/Support/ManagedStatic.h"
-#include "llvm/Support/PrettyStackTrace.h"
-#include "llvm/Support/Signals.h"
 #include "llvm/Support/raw_ostream.h"
 #include <functional>
 #include <system_error>
@@ -21,10 +19,6 @@ using namespace llvm;
 using namespace object;
 
 int convertForTestingMain(int argc, const char *argv[]) {
-  sys::PrintStackTraceOnErrorSignal();
-  PrettyStackTraceProgram X(argc, argv);
-  llvm_shutdown_obj Y; // Call llvm_shutdown() on exit.
-
   cl::opt<std::string> InputSourceFile(cl::Positional, cl::Required,
                                        cl::desc("<Source file>"));
 
@@ -36,8 +30,12 @@ int convertForTestingMain(int argc, const char *argv[]) {
   cl::ParseCommandLineOptions(argc, argv, "LLVM code coverage tool\n");
 
   auto ObjErr = llvm::object::ObjectFile::createObjectFile(InputSourceFile);
-  if (auto Err = ObjErr.getError()) {
-    errs() << "error: " << Err.message() << "\n";
+  if (!ObjErr) {
+    std::string Buf;
+    raw_string_ostream OS(Buf);
+    logAllUnhandledErrors(ObjErr.takeError(), OS, "");
+    OS.flush();
+    errs() << "error: " << Buf;
     return 1;
   }
   ObjectFile *OF = ObjErr.get().getBinary();
@@ -54,9 +52,9 @@ int convertForTestingMain(int argc, const char *argv[]) {
     StringRef Name;
     if (Section.getName(Name))
       return 1;
-    if (Name == "__llvm_prf_names") {
+    if (Name == llvm::getInstrProfNameSectionName(false)) {
       ProfileNames = Section;
-    } else if (Name == "__llvm_covmap") {
+    } else if (Name == llvm::getInstrProfCoverageSectionName(false)) {
       CoverageMapping = Section;
     } else
       continue;
@@ -84,7 +82,11 @@ int convertForTestingMain(int argc, const char *argv[]) {
   OS << "llvmcovmtestdata";
   encodeULEB128(ProfileNamesData.size(), OS);
   encodeULEB128(ProfileNamesAddress, OS);
-  OS << ProfileNamesData << CoverageMappingData;
+  OS << ProfileNamesData;
+  // Coverage mapping data is expected to have an alignment of 8.
+  for (unsigned Pad = OffsetToAlignment(OS.tell(), 8); Pad; --Pad)
+    OS.write(uint8_t(0));
+  OS << CoverageMappingData;
 
   return 0;
 }
diff --git a/tools/llvm-cov/gcov.cpp b/tools/llvm-cov/gcov.cpp
index a5343fa29afc3..4652fed2a384e 100644
--- a/tools/llvm-cov/gcov.cpp
+++ b/tools/llvm-cov/gcov.cpp
@@ -16,10 +16,7 @@
 #include "llvm/Support/Errc.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/GCOV.h"
-#include "llvm/Support/ManagedStatic.h"
 #include "llvm/Support/Path.h"
-#include "llvm/Support/PrettyStackTrace.h"
-#include "llvm/Support/Signals.h"
 #include <system_error>
 using namespace llvm;
 
@@ -85,11 +82,6 @@ static void reportCoverage(StringRef SourceFile, StringRef ObjectDir,
 }
 
 int gcovMain(int argc, const char *argv[]) {
-  // Print a stack trace if we signal out.
-  sys::PrintStackTraceOnErrorSignal();
-  PrettyStackTraceProgram X(argc, argv);
-  llvm_shutdown_obj Y; // Call llvm_shutdown() on exit.
-
   cl::list<std::string> SourceFiles(cl::Positional, cl::OneOrMore,
                                     cl::desc("SOURCEFILE"));
 
diff --git a/tools/llvm-cov/llvm-cov.cpp b/tools/llvm-cov/llvm-cov.cpp
index 8c5acaef63b25..ba60cd91da906 100644
--- a/tools/llvm-cov/llvm-cov.cpp
+++ b/tools/llvm-cov/llvm-cov.cpp
@@ -14,8 +14,11 @@
 #include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/StringSwitch.h"
 #include "llvm/Support/CommandLine.h"
+#include "llvm/Support/ManagedStatic.h"
 #include "llvm/Support/Path.h"
+#include "llvm/Support/PrettyStackTrace.h"
 #include "llvm/Support/Process.h"
+#include "llvm/Support/Signals.h"
 #include "llvm/Support/raw_ostream.h"
 #include <string>
 
@@ -51,6 +54,11 @@ static int versionMain(int argc, const char *argv[]) {
 }
 
 int main(int argc, const char **argv) {
+  // Print a stack trace if we signal out.
+  sys::PrintStackTraceOnErrorSignal(argv[0]);
+  PrettyStackTraceProgram X(argc, argv);
+  llvm_shutdown_obj Y; // Call llvm_shutdown() on exit.
+
   // If argv[0] is or ends with 'gcov', always be gcov compatible
   if (sys::path::stem(argv[0]).endswith_lower("gcov"))
     return gcovMain(argc, argv);