diff --git a/include/clang/Basic/DiagnosticFrontendKinds.td b/include/clang/Basic/DiagnosticFrontendKinds.td
index b1453e3..2e0b4ba 100644
--- a/include/clang/Basic/DiagnosticFrontendKinds.td
+++ b/include/clang/Basic/DiagnosticFrontendKinds.td
@@ -22,7 +22,7 @@
 def err_fe_stderr_binary : Error<"unable to change standard error to binary">,
   DefaultFatal;
 def err_fe_dependency_file_requires_MT : Error<
-    "-dependency-file requires at least one -MT option">;
+    "-dependency-file requires at least one -MT or -MQ option">;
 def err_fe_incompatible_options : Error<
     "'%0' cannot be used with '%1'">, DefaultFatal;
 def err_fe_no_fixit_and_codegen : Error<
diff --git a/include/clang/Driver/CC1Options.td b/include/clang/Driver/CC1Options.td
index 488e336..124288a 100644
--- a/include/clang/Driver/CC1Options.td
+++ b/include/clang/Driver/CC1Options.td
@@ -156,6 +156,7 @@
   HelpText<"Filename (or -) to write dependency output to">;
 def sys_header_deps : Flag<"-sys-header-deps">,
   HelpText<"Include system headers in dependency output">;
+def MQ : Separate<"-MQ">, HelpText<"Specify target to quote for dependency">;
 def MT : Separate<"-MT">, HelpText<"Specify target for dependency">;
 def MP : Flag<"-MP">,
   HelpText<"Create phony target for each dependency (other than main file)">;
diff --git a/lib/Driver/Tools.cpp b/lib/Driver/Tools.cpp
index e5ee287..2a37991 100644
--- a/lib/Driver/Tools.cpp
+++ b/lib/Driver/Tools.cpp
@@ -56,6 +56,35 @@
         << A->getAsString(Args) << "-static";
 }
 
+// Quote target names for inclusion in GNU Make dependency files.
+// Only the characters '$', '#', ' ', '\t' are quoted.
+static void QuoteTarget(llvm::StringRef Target,
+                        llvm::SmallVectorImpl<char> &Res) {
+  for (unsigned i = 0, e = Target.size(); i != e; ++i) {
+    switch (Target[i]) {
+    case ' ':
+    case '\t':
+      // Escape the preceding backslashes
+      for (int j = i - 1; j >= 0 && Target[j] == '\\'; --j)
+        Res.push_back('\\');
+
+      // Escape the space/tab
+      Res.push_back('\\');
+      break;
+    case '$':
+      Res.push_back('$');
+      break;
+    case '#':
+      Res.push_back('\\');
+      break;
+    default:
+      break;
+    }
+
+    Res.push_back(Target[i]);
+  }
+}
+
 void Clang::AddPreprocessingOptions(const Driver &D,
                                     const ArgList &Args,
                                     ArgStringList &CmdArgs,
@@ -91,9 +120,7 @@
     CmdArgs.push_back("-dependency-file");
     CmdArgs.push_back(DepFile);
 
-    // Add an -MT option if the user didn't specify their own.
-    //
-    // FIXME: This should use -MQ, when we support it.
+    // Add a default target if one wasn't specified.
     if (!Args.hasArg(options::OPT_MT) && !Args.hasArg(options::OPT_MQ)) {
       const char *DepTarget;
 
@@ -114,7 +141,9 @@
       }
 
       CmdArgs.push_back("-MT");
-      CmdArgs.push_back(DepTarget);
+      llvm::SmallString<128> Quoted;
+      QuoteTarget(DepTarget, Quoted);
+      CmdArgs.push_back(Args.MakeArgString(Quoted));
     }
 
     if (A->getOption().matches(options::OPT_M) ||
@@ -123,7 +152,25 @@
   }
 
   Args.AddLastArg(CmdArgs, options::OPT_MP);
-  Args.AddAllArgs(CmdArgs, options::OPT_MT);
+
+  // Convert all -MQ <target> args to -MT <quoted target>
+  for (arg_iterator it = Args.filtered_begin(options::OPT_MT,
+                                             options::OPT_MQ),
+         ie = Args.filtered_end(); it != ie; ++it) {
+
+    it->claim();
+
+    if (it->getOption().matches(options::OPT_MQ)) {
+      CmdArgs.push_back("-MT");
+      llvm::SmallString<128> Quoted;
+      QuoteTarget(it->getValue(Args), Quoted);
+      CmdArgs.push_back(Args.MakeArgString(Quoted));
+
+    // -MT flag - no change
+    } else {
+      it->render(Args, CmdArgs);
+    }
+  }
 
   // Add -i* options, and automatically translate to
   // -include-pch/-include-pth for transparent PCH support. It's
@@ -930,7 +977,6 @@
 
   Arg *Unsupported;
   if ((Unsupported = Args.getLastArg(options::OPT_MG)) ||
-      (Unsupported = Args.getLastArg(options::OPT_MQ)) ||
       (Unsupported = Args.getLastArg(options::OPT_iframework)) ||
       (Unsupported = Args.getLastArg(options::OPT_fshort_enums)))
     D.Diag(clang::diag::err_drv_clang_unsupported)
diff --git a/test/Preprocessor/dependencies-and-pp.c b/test/Preprocessor/dependencies-and-pp.c
index d7bf4df..7877df3 100644
--- a/test/Preprocessor/dependencies-and-pp.c
+++ b/test/Preprocessor/dependencies-and-pp.c
@@ -1,5 +1,31 @@
+// Test -MT and -E flags, PR4063
+
 // RUN: %clang -E -o %t.1 %s
 // RUN: %clang -E -MD -MF %t.d -MT foo -o %t.2 %s
 // RUN: diff %t.1 %t.2
 // RUN: grep "foo:" %t.d
 // RUN: grep "dependencies-and-pp.c" %t.d
+
+// Test -MQ flag without quoting
+
+// RUN: %clang -E -MD -MF %t.d -MQ foo -o %t %s
+// RUN: grep "foo:" %t.d
+
+// Test -MQ flag with quoting
+
+// RUN: %clang -E -MD -MF %t.d -MQ '$fo\ooo ooo\ ooo\\ ooo#oo' -o %t %s
+// RUN: fgrep '$$fo\ooo\ ooo\\\ ooo\\\\\ ooo\#oo:' %t.d
+
+// Test consecutive -MT flags
+
+// RUN: %clang -E -MD -MF %t.d -MT foo -MT bar -MT baz -o %t %s
+// RUN: diff %t.1 %t
+// RUN: fgrep "foo bar baz:" %t.d
+
+// Test consecutive -MT and -MQ flags
+
+// RUN: %clang -E -MD -MF %t.d -MT foo -MQ '$(bar)' -MT 'b az' -MQ 'qu ux' -MQ ' space' -o %t %s
+// RUN: fgrep 'foo $$(bar) b az qu\ ux \ space:' %t.d
+
+// TODO: Test default target without quoting
+// TODO: Test default target with quoting