Index: clang-tidy/CMakeLists.txt
===================================================================
--- clang-tidy/CMakeLists.txt
+++ clang-tidy/CMakeLists.txt
@@ -26,6 +26,7 @@
   )
 
 add_subdirectory(tool)
+add_subdirectory(plugin)
 add_subdirectory(cert)
 add_subdirectory(llvm)
 add_subdirectory(cppcoreguidelines)
Index: clang-tidy/ClangTidyDiagnosticConsumer.h
===================================================================
--- clang-tidy/ClangTidyDiagnosticConsumer.h
+++ clang-tidy/ClangTidyDiagnosticConsumer.h
@@ -221,6 +221,7 @@
 private:
   // Calls setDiagnosticsEngine() and storeError().
   friend class ClangTidyDiagnosticConsumer;
+  friend class ClangTidyPluginAction;
 
   /// \brief Sets the \c DiagnosticsEngine so that Diagnostics can be generated
   /// correctly.
Index: clang-tidy/plugin/CMakeLists.txt
===================================================================
--- /dev/null
+++ clang-tidy/plugin/CMakeLists.txt
@@ -0,0 +1,20 @@
+add_clang_library(clangTidyPlugin
+  ClangTidyPlugin.cpp
+
+  LINK_LIBS
+  clangAST
+  clangASTMatchers
+  clangBasic
+  clangFrontend
+  clangSema
+  clangTidy
+  clangTidyCERTModule
+  clangTidyCppCoreGuidelinesModule
+  clangTidyGoogleModule
+  clangTidyLLVMModule
+  clangTidyMiscModule
+  clangTidyModernizeModule
+  clangTidyPerformanceModule
+  clangTidyReadabilityModule
+  clangTooling
+  )
Index: clang-tidy/plugin/ClangTidyPlugin.cpp
===================================================================
--- /dev/null
+++ clang-tidy/plugin/ClangTidyPlugin.cpp
@@ -0,0 +1,122 @@
+//===- ClangTidyPlugin.cpp - clang-tidy as a clang plugin -----------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "../ClangTidy.h"
+#include "../ClangTidyModule.h"
+#include "clang/Frontend/CompilerInstance.h"
+#include "clang/Frontend/FrontendPluginRegistry.h"
+#include "clang/Frontend/MultiplexConsumer.h"
+
+namespace clang {
+namespace tidy {
+
+/// The core clang tidy plugin action. This just provides the AST consumer and
+/// command line flag parsing for using clang-tidy as a clang plugin.
+class ClangTidyPluginAction : public PluginASTAction {
+  /// Wrapper to grant the context the same lifetime as the action. We use
+  /// MultiplexConsumer to avoid writing out all the forwarding methods.
+  class WrapConsumer : public MultiplexConsumer {
+    std::unique_ptr<ClangTidyContext> Context;
+
+  public:
+    WrapConsumer(std::unique_ptr<ClangTidyContext> Context,
+                 std::vector<std::unique_ptr<ASTConsumer>> Consumer)
+        : MultiplexConsumer(std::move(Consumer)), Context(std::move(Context)) {}
+  };
+
+public:
+  std::unique_ptr<ASTConsumer> CreateASTConsumer(CompilerInstance &Compiler,
+                                                 StringRef File) override {
+    // Insert the current diagnostics engine.
+    Context->setDiagnosticsEngine(&Compiler.getDiagnostics());
+
+    // Create the AST consumer.
+    ClangTidyASTConsumerFactory Factory(*Context);
+    std::vector<std::unique_ptr<ASTConsumer>> Vec;
+    Vec.push_back(Factory.CreateASTConsumer(Compiler, File));
+
+    return llvm::make_unique<WrapConsumer>(std::move(Context), std::move(Vec));
+  }
+
+  bool ParseArgs(const CompilerInstance &,
+                 const std::vector<std::string> &Args) override {
+    ClangTidyGlobalOptions GlobalOptions;
+    ClangTidyOptions DefaultOptions;
+    ClangTidyOptions OverrideOptions;
+
+    // Parse the extra command line args.
+    // FIXME: This is very limited at the moment.
+    for (StringRef Arg : Args)
+      if (Arg.startswith("-checks="))
+        OverrideOptions.Checks = Arg.substr(strlen("-checks="));
+
+    auto Options = llvm::make_unique<FileOptionsProvider>(
+        GlobalOptions, DefaultOptions, OverrideOptions);
+    Context = llvm::make_unique<ClangTidyContext>(std::move(Options));
+    return true;
+  }
+
+private:
+  std::unique_ptr<ClangTidyContext> Context;
+};
+} // namespace tidy
+} // namespace clang
+
+// This anchor is used to force the linker to link in the generated object file
+// and thus register the clang-tidy plugin.
+volatile int ClangTidyPluginAnchorSource = 0;
+
+static clang::FrontendPluginRegistry::Add<clang::tidy::ClangTidyPluginAction>
+    X("clang-tidy", "clang-tidy");
+
+namespace clang {
+namespace tidy {
+
+// This anchor is used to force the linker to link the CERTModule.
+extern volatile int CERTModuleAnchorSource;
+static int LLVM_ATTRIBUTE_UNUSED CERTModuleAnchorDestination =
+    CERTModuleAnchorSource;
+
+// This anchor is used to force the linker to link the LLVMModule.
+extern volatile int LLVMModuleAnchorSource;
+static int LLVM_ATTRIBUTE_UNUSED LLVMModuleAnchorDestination =
+    LLVMModuleAnchorSource;
+
+// This anchor is used to force the linker to link the CppCoreGuidelinesModule.
+extern volatile int CppCoreGuidelinesModuleAnchorSource;
+static int LLVM_ATTRIBUTE_UNUSED CppCoreGuidelinesModuleAnchorDestination =
+    CppCoreGuidelinesModuleAnchorSource;
+
+// This anchor is used to force the linker to link the GoogleModule.
+extern volatile int GoogleModuleAnchorSource;
+static int LLVM_ATTRIBUTE_UNUSED GoogleModuleAnchorDestination =
+    GoogleModuleAnchorSource;
+
+// This anchor is used to force the linker to link the MiscModule.
+extern volatile int MiscModuleAnchorSource;
+static int LLVM_ATTRIBUTE_UNUSED MiscModuleAnchorDestination =
+    MiscModuleAnchorSource;
+
+// This anchor is used to force the linker to link the ModernizeModule.
+extern volatile int ModernizeModuleAnchorSource;
+static int LLVM_ATTRIBUTE_UNUSED ModernizeModuleAnchorDestination =
+    ModernizeModuleAnchorSource;
+
+// This anchor is used to force the linker to link the PerformanceModule.
+extern volatile int PerformanceModuleAnchorSource;
+static int LLVM_ATTRIBUTE_UNUSED PerformanceModuleAnchorDestination =
+    PerformanceModuleAnchorSource;
+
+// This anchor is used to force the linker to link the ReadabilityModule.
+extern volatile int ReadabilityModuleAnchorSource;
+static int LLVM_ATTRIBUTE_UNUSED ReadabilityModuleAnchorDestination =
+    ReadabilityModuleAnchorSource;
+
+} // namespace tidy
+} // namespace clang
Index: test/clang-tidy/basic.cpp
===================================================================
--- test/clang-tidy/basic.cpp
+++ test/clang-tidy/basic.cpp
@@ -1,4 +1,5 @@
 // RUN: clang-tidy %s -checks='-*,llvm-namespace-comment' -- | FileCheck %s
+// RUN: c-index-test -test-load-source-reparse 2 all %s -Xclang -add-plugin -Xclang clang-tidy -Xclang -plugin-arg-clang-tidy -Xclang -checks='-*,llvm-namespace-comment' 2>&1 | FileCheck %s
 
 namespace i {
 }