Index: clang-tools-extra/trunk/clang-tidy/ClangTidy.cpp
===================================================================
--- clang-tools-extra/trunk/clang-tidy/ClangTidy.cpp
+++ clang-tools-extra/trunk/clang-tidy/ClangTidy.cpp
@@ -481,6 +481,16 @@
   ClangTool Tool(Compilations, InputFiles,
                  std::make_shared<PCHContainerOperations>(), BaseFS);
 
+  // Add __clang_analyzer__ macro definition for compatibility with the clang
+  // static analyzer.
+  ArgumentsAdjuster ClangTidyMacroDefinitionInserter =
+      [&Context](const CommandLineArguments &Args, StringRef Filename) {
+        ClangTidyOptions Opts = Context.getOptionsForFile(Filename);
+        CommandLineArguments AdjustedArgs = Args;
+        AdjustedArgs.emplace_back("-D__clang_analyzer__");
+        return AdjustedArgs;
+      };
+
   // Add extra arguments passed by the clang-tidy command-line.
   ArgumentsAdjuster PerFileExtraArgumentsInserter =
       [&Context](const CommandLineArguments &Args, StringRef Filename) {
@@ -515,6 +525,7 @@
         return AdjustedArgs;
       };
 
+  Tool.appendArgumentsAdjuster(ClangTidyMacroDefinitionInserter);
   Tool.appendArgumentsAdjuster(PerFileExtraArgumentsInserter);
   Tool.appendArgumentsAdjuster(PluginArgumentsRemover);
   if (Profile)
Index: clang-tools-extra/trunk/test/clang-tidy/clang-tidy-__clang_analyzer__macro.cpp
===================================================================
--- clang-tools-extra/trunk/test/clang-tidy/clang-tidy-__clang_analyzer__macro.cpp
+++ clang-tools-extra/trunk/test/clang-tidy/clang-tidy-__clang_analyzer__macro.cpp
@@ -0,0 +1,8 @@
+// RUN: %check_clang_tidy %s * %t
+
+#if defined(__clang_analyzer__)
+#warning __clang_analyzer__ is defined
+#endif
+// CHECK-MESSAGES: :[[@LINE-2]]:2: warning: __clang_analyzer__ is defined [clang-diagnostic-#warnings]
+
+