ss.diff

diff --git a/clang/include/clang/Basic/DiagnosticDriverKinds.td b/clang/include/clang/Basic/DiagnosticDriverKinds.td
index 3833f0f..c401198 100644
--- a/clang/include/clang/Basic/DiagnosticDriverKinds.td
+++ b/clang/include/clang/Basic/DiagnosticDriverKinds.td
@@ -45,7 +45,7 @@ def err_drv_invalid_rtlib_name : Error<
 def err_drv_unsupported_rtlib_for_platform : Error<
   "unsupported runtime library '%0' for platform '%1'">;
 def err_drv_invalid_stdlib_name : Error<
-  "invalid library name in argument '%0'">;
+  "invalid library name in argument '%0'. Do you mean "%1"? ">;
 def err_drv_invalid_output_with_multiple_archs : Error<
   "cannot use '%0' output with multiple -arch options">;
 def err_drv_no_input_files : Error<"no input files">;
diff --git a/clang/include/clang/Driver/Options.h b/clang/include/clang/Driver/Options.h
index 57e4452..f539f41 100644
--- a/clang/include/clang/Driver/Options.h
+++ b/clang/include/clang/Driver/Options.h
@@ -21,6 +21,12 @@ class OptTable;
 namespace clang {
 namespace driver {
 
+namespace ArgValues {
+  enum class stdlib {
+    libcxx, stdlibcxx, platform
+  }
+}
+
 namespace options {
 /// Flags specifically for clang options.  Must not overlap with
 /// llvm::opt::DriverFlag.
diff --git a/clang/lib/Driver/Driver.cpp b/clang/lib/Driver/Driver.cpp
index f36deff..a8e1e4b 100644
--- a/clang/lib/Driver/Driver.cpp
+++ b/clang/lib/Driver/Driver.cpp
@@ -443,22 +443,21 @@ void Driver::setLTOMode(const llvm::opt::ArgList &Args) {
                     options::OPT_fno_lto, false))
     return;
 
-  StringRef LTOName("full");
-
+  OptValue LTOName = options::VAL_lto_full;
   const Arg *A = Args.getLastArg(options::OPT_flto_EQ);
   if (A)
-    LTOName = A->getValue();
-
-  LTOMode = llvm::StringSwitch<LTOKind>(LTOName)
-                .Case("full", LTOK_Full)
-                .Case("thin", LTOK_Thin)
-                .Default(LTOK_Unknown);
+    LTOName = A->getEnumValue();
 
-  if (LTOMode == LTOK_Unknown) {
-    assert(A);
-    Diag(diag::err_drv_unsupported_option_argument) << A->getOption().getName()
+    switch (LTOName) {
+      case VAL_lto_full:
+        return LTOK_Full;
+      case VAL_lto_thin:
+        return LTOK_Thin;
+      default:
+        assert(A);
+        Diag(diag::err_drv_unsupported_option_argument) << A->getOption().getName()
                                                     << A->getValue();
-  }
+    }
 }
 
 /// Compute the desired OpenMP runtime from the flags provided.
diff --git a/clang/lib/Driver/ToolChain.cpp b/clang/lib/Driver/ToolChain.cpp
index 4f82503..8122e90 100644
--- a/clang/lib/Driver/ToolChain.cpp
+++ b/clang/lib/Driver/ToolChain.cpp
@@ -581,15 +581,15 @@ ToolChain::CXXStdlibType ToolChain::GetCXXStdlibType(const ArgList &Args) const{
   StringRef LibName = A ? A->getValue() : CLANG_DEFAULT_CXX_STDLIB;
 
   // Only use "platform" in tests to override CLANG_DEFAULT_CXX_STDLIB!
-  if (LibName == "libc++")
-    return ToolChain::CST_Libcxx;
-  else if (LibName == "libstdc++")
-    return ToolChain::CST_Libstdcxx;
-  else if (LibName == "platform")
-    return GetDefaultCXXStdlibType();
+  switch(LibName) {
+    ArgValues::stdlib::libcxx : return ToolChain::CST_Libcxx; break;
+    ArgValues::stdlib::stdlibcxx : return ToolChain::CST_Libcstdxx; break;
+    ArgValues::stdlib::platform : return GetDefaultCXXStdlibType(); break;
+  }
 
   if (A)
-    getDriver().Diag(diag::err_drv_invalid_stdlib_name) << A->getAsString(Args);
+    getDriver().Diag(diag::err_drv_invalid_stdlib_name) << A->getAsString(Args)
+      << ArgValues::stdlib::libcxx ;
 
   return GetDefaultCXXStdlibType();
 }