Index: include/clang/Format/Format.h
===================================================================
--- include/clang/Format/Format.h
+++ include/clang/Format/Format.h
@@ -1963,6 +1963,11 @@
 /// of ``getStyle()``.
 extern const char *StyleOptionHelpDescription;
 
+/// The suggested format style to use by default. This allows tools using
+/// `getStyle` to have a consistent default style.
+/// Different builds can modify the value to the preferred styles.
+extern const char *DefaultFormatStyle;
+
 /// Construct a FormatStyle based on ``StyleName``.
 ///
 /// ``StyleName`` can take several forms:
Index: lib/Format/Format.cpp
===================================================================
--- lib/Format/Format.cpp
+++ lib/Format/Format.cpp
@@ -2144,6 +2144,8 @@
   return GuessedLanguage;
 }
 
+const char *DefaultFormatStyle = "file";
+
 llvm::Expected<FormatStyle> getStyle(StringRef StyleName, StringRef FileName,
                                      StringRef FallbackStyleName,
                                      StringRef Code, vfs::FileSystem *FS) {
Index: tools/clang-format/ClangFormat.cpp
===================================================================
--- tools/clang-format/ClangFormat.cpp
+++ tools/clang-format/ClangFormat.cpp
@@ -60,9 +60,9 @@
                              "Can only be used with one input file."),
            cl::cat(ClangFormatCategory));
 static cl::opt<std::string>
-    Style("style",
-          cl::desc(clang::format::StyleOptionHelpDescription),
-          cl::init("file"), cl::cat(ClangFormatCategory));
+    Style("style", cl::desc(clang::format::StyleOptionHelpDescription),
+          cl::init(clang::format::DefaultFormatStyle),
+          cl::cat(ClangFormatCategory));
 static cl::opt<std::string>
 FallbackStyle("fallback-style",
               cl::desc("The name of the predefined style used as a\n"