diff --git a/clang-tools-extra/cpp11-migrate/Core/Transform.h b/clang-tools-extra/cpp11-migrate/Core/Transform.h
index 264b59526a78..17ec6ce91206 100644
--- a/clang-tools-extra/cpp11-migrate/Core/Transform.h
+++ b/clang-tools-extra/cpp11-migrate/Core/Transform.h
@@ -111,6 +111,15 @@ struct TransformOptions {
   /// \brief Enable the use of performance timers.
   bool EnableTiming;
 
+  /// \brief Allow changes to headers included from the main source file.
+  /// Transform sub-classes should use ModifiableHeaders to determine which
+  /// headers are modifiable and which are not.
+  bool EnableHeaderModifications;
+
+  /// \brief Contains information on which headers are safe to transform and
+  /// which aren't.
+  IncludeExcludeInfo ModifiableHeaders;
+
   /// \brief Maximum allowed level of risk.
   RiskLevel MaxRiskLevel;
 };
diff --git a/clang-tools-extra/cpp11-migrate/tool/Cpp11Migrate.cpp b/clang-tools-extra/cpp11-migrate/tool/Cpp11Migrate.cpp
index cd2e653fbc66..da9edb460afe 100644
--- a/clang-tools-extra/cpp11-migrate/tool/Cpp11Migrate.cpp
+++ b/clang-tools-extra/cpp11-migrate/tool/Cpp11Migrate.cpp
@@ -79,6 +79,15 @@ ExcludeFromFile("exclude-from", cl::Hidden, cl::value_desc("filename"),
                 cl::desc("File containing a list of paths that can not be "
                          "transforms"));
 
+// Header modifications will probably be always on eventually. For now, they
+// need to be explicitly enabled.
+static cl::opt<bool, /*ExternalStorage=*/true> EnableHeaderModifications(
+    "headers",
+    cl::Hidden, // Experimental feature for now.
+    cl::desc("Enable modifications to headers"),
+    cl::location(GlobalOptions.EnableHeaderModifications),
+    cl::init(false));
+
 class EndSyntaxArgumentsAdjuster : public ArgumentsAdjuster {
   CommandLineArguments Adjust(const CommandLineArguments &Args) {
     CommandLineArguments AdjustedArgs = Args;
@@ -113,6 +122,15 @@ int main(int argc, const char **argv) {
   // against the default value when the command line option is not specified.
   GlobalOptions.EnableTiming = (TimingDirectoryName != NoTiming);
 
+  // Populate the ModifiableHeaders structure if header modifications are
+  // enabled.
+  if (GlobalOptions.EnableHeaderModifications) {
+    GlobalOptions.ModifiableHeaders
+        .readListFromString(IncludePaths, ExcludePaths);
+    GlobalOptions.ModifiableHeaders
+        .readListFromFile(IncludeFromFile, ExcludeFromFile);
+  }
+
   TransformManager.createSelectedTransforms(GlobalOptions);
 
   if (TransformManager.begin() == TransformManager.end()) {