Allow disabling of wchar_t type.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@163221 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Frontend/CompilerInvocation.cpp b/lib/Frontend/CompilerInvocation.cpp
index 6bffa13..bf1a80c 100644
--- a/lib/Frontend/CompilerInvocation.cpp
+++ b/lib/Frontend/CompilerInvocation.cpp
@@ -797,6 +797,8 @@
     Res.push_back("-fno-access-control");
   if (!Opts.CharIsSigned)
     Res.push_back("-fno-signed-char");
+  if (Opts.CPlusPlus && !Opts.WChar)
+    Res.push_back("-fno-wchar");
   if (Opts.ShortWChar)
     Res.push_back("-fshort-wchar");
   if (!Opts.ElideConstructors)
@@ -1871,6 +1873,9 @@
   // OpenCL and C++ both have bool, true, false keywords.
   Opts.Bool = Opts.OpenCL || Opts.CPlusPlus;
 
+  // C++ has wchar_t keyword.
+  Opts.WChar = Opts.CPlusPlus;
+
   Opts.GNUKeywords = Opts.GNUMode;
   Opts.CXXOperatorNames = Opts.CPlusPlus;
 
@@ -2078,6 +2083,7 @@
   Opts.BlocksRuntimeOptional = Args.hasArg(OPT_fblocks_runtime_optional);
   Opts.Modules = Args.hasArg(OPT_fmodules);
   Opts.CharIsSigned = !Args.hasArg(OPT_fno_signed_char);
+  Opts.WChar = Opts.CPlusPlus && !Args.hasArg(OPT_fno_wchar);
   Opts.ShortWChar = Args.hasArg(OPT_fshort_wchar);
   Opts.ShortEnums = Args.hasArg(OPT_fshort_enums);
   Opts.Freestanding = Args.hasArg(OPT_ffreestanding);
diff --git a/lib/Frontend/InitPreprocessor.cpp b/lib/Frontend/InitPreprocessor.cpp
index e24aebd..6aeb05f 100644
--- a/lib/Frontend/InitPreprocessor.cpp
+++ b/lib/Frontend/InitPreprocessor.cpp
@@ -420,11 +420,13 @@
     // Both __PRETTY_FUNCTION__ and __FUNCTION__ are GCC extensions, however
     // VC++ appears to only like __FUNCTION__.
     Builder.defineMacro("__PRETTY_FUNCTION__", "__FUNCTION__");
-    // Work around some issues with Visual C++ headerws.
-    if (LangOpts.CPlusPlus) {
-      // Since we define wchar_t in C++ mode.
+    // Work around some issues with Visual C++ headers.
+    if (LangOpts.WChar) {
+      // wchar_t supported as a keyword.
       Builder.defineMacro("_WCHAR_T_DEFINED");
       Builder.defineMacro("_NATIVE_WCHAR_T_DEFINED");
+    }
+    if (LangOpts.CPlusPlus) {
       // FIXME: Support Microsoft's __identifier extension in the lexer.
       Builder.append("#define __identifier(x) x");
       Builder.append("class type_info;");