Index: clang-tools-extra/clang-apply-replacements/tool/ClangApplyReplacementsMain.cpp
===================================================================
--- clang-tools-extra/clang-apply-replacements/tool/ClangApplyReplacementsMain.cpp
+++ clang-tools-extra/clang-apply-replacements/tool/ClangApplyReplacementsMain.cpp
@@ -48,6 +48,10 @@
              "Use -style to choose formatting style.\n"),
     cl::cat(FormattingCategory));
 
+static cl::opt<bool> ForceOverwriteReadOnly(
+    "force", cl::desc("Overwrite read-only files when applying replacements\n"),
+    cl::init(false), cl::cat(ReplacementCategory));
+
 // FIXME: Consider making the default behaviour for finding a style
 // configuration file to start the search anew for every file being changed to
 // handle situations where the style is different for different parts of a
@@ -152,6 +156,13 @@
 
     // Write new file to disk
     std::error_code EC;
+    if (ForceOverwriteReadOnly) {
+      using namespace llvm::sys::fs;
+      if (auto ErrorOrPerms = getPermissions(FileName)) {
+        perms P = ErrorOrPerms.get();
+        setPermissions(FileName, P | all_write);
+      }
+    }
     llvm::raw_fd_ostream FileStream(FileName, EC, llvm::sys::fs::OF_None);
     if (EC) {
       llvm::errs() << "Could not open " << FileName << " for writing\n";