diff --git a/include/clang/Driver/Arg.h b/include/clang/Driver/Arg.h
index 30bb56a..a9e34d2 100644
--- a/include/clang/Driver/Arg.h
+++ b/include/clang/Driver/Arg.h
@@ -95,6 +95,10 @@
     static bool classof(const Arg *) { return true; }    
 
     void dump() const;
+
+    /// getAsString - Return a formatted version of the argument and
+    /// its values, for debugging and diagnostics.
+    std::string getAsString(const ArgList &Args) const;
   };
 
   /// FlagArg - An argument with no value.
diff --git a/lib/Driver/Arg.cpp b/lib/Driver/Arg.cpp
index eba39dd..c43c9fb 100644
--- a/lib/Driver/Arg.cpp
+++ b/lib/Driver/Arg.cpp
@@ -50,6 +50,22 @@
   llvm::errs() << ">\n";
 }
 
+std::string Arg::getAsString(const ArgList &Args) const {
+  std::string Res;
+  llvm::raw_string_ostream OS(Res);
+
+  ArgStringList ASL;
+  render(Args, ASL);
+  for (ArgStringList::iterator 
+         it = ASL.begin(), ie = ASL.end(); it != ie; ++it) {
+    if (it != ASL.begin())
+      OS << ' ';
+    OS << *it;
+  }
+
+  return OS.str();
+}
+
 void Arg::renderAsInput(const ArgList &Args, ArgStringList &Output) const {
   if (!getOption().hasNoOptAsInput()) {
     render(Args, Output);
diff --git a/lib/Driver/Driver.cpp b/lib/Driver/Driver.cpp
index 2ae8826..2c32401 100644
--- a/lib/Driver/Driver.cpp
+++ b/lib/Driver/Driver.cpp
@@ -75,7 +75,7 @@
     Arg *A = getOpts().ParseOneArg(*Args, Index, End);
     if (A) {
       if (A->getOption().isUnsupported()) {
-        Diag(clang::diag::err_drv_unsupported_opt) << A->getOption().getName();
+        Diag(clang::diag::err_drv_unsupported_opt) << A->getAsString(*Args);
         continue;
       }
 
@@ -368,10 +368,10 @@
     // overwriting the same files.
     if (const Arg *A = Args.getLastArg(options::OPT_M_Group))
       Diag(clang::diag::err_drv_invalid_opt_with_multiple_archs) 
-        << A->getOption().getName();
+        << A->getAsString(Args);
     if (const Arg *A = Args.getLastArg(options::OPT_save_temps))
       Diag(clang::diag::err_drv_invalid_opt_with_multiple_archs) 
-        << A->getOption().getName();
+        << A->getAsString(Args);
   }
 
   ActionList SingleActions;
@@ -534,7 +534,7 @@
   // Reject -Z* at the top level, these options should never have been
   // exposed by gcc.
   if (Arg *A = Args.getLastArg(options::OPT_Z))
-    Diag(clang::diag::err_drv_use_of_Z_option) << A->getValue(Args);
+    Diag(clang::diag::err_drv_use_of_Z_option) << A->getAsString(Args);
 
   // Construct the actions to perform.
   ActionList LinkerInputs;
@@ -552,7 +552,7 @@
       // Claim here to avoid the more general unused warning.
       InputArg->claim();
       Diag(clang::diag::warn_drv_input_file_unused) 
-        << InputArg->getValue(Args)
+        << InputArg->getAsString(Args)
         << getPhaseName(InitialPhase)
         << FinalPhaseArg->getOption().getName();
       continue;
@@ -699,7 +699,7 @@
     // printed.
     if (!A->isClaimed())
       Diag(clang::diag::warn_drv_unused_argument) 
-        << A->getOption().getName();
+        << A->getAsString(C.getArgs());
   }
 }