Correctly detect sign-ness of wchar_t

[tberghammer]

Summary

Correctly detect sign-ness of wchar_t

The underlying type of wchar_t is not defined by the standard. This CL
add logic to correctly use the type specified for the current target
based on TargetInfo.

[tberghammer]

r233795

source/Symbol/ClangASTContext.cpp

if (ast)
                 if (QualTypeMatchesBitSize (bit_size, ast, ast->LongDoubleTy))
                     return ClangASTType (ast, ast->LongDoubleTy.getAsOpaquePtr());
                 break;
                 
             case DW_ATE_signed:
                 if (type_name)
                 {
                     if (streq(type_name, "wchar_t") &&
-                        QualTypeMatchesBitSize (bit_size, ast, ast->WCharTy))
+                        QualTypeMatchesBitSize (bit_size, ast, ast->WCharTy) &&
+                        TargetInfo::isTypeSigned (getTargetInfo()->getWCharType()))
                         return ClangASTType (ast, ast->WCharTy.getAsOpaquePtr());
                     if (streq(type_name, "void") &&
                         QualTypeMatchesBitSize (bit_size, ast, ast->VoidTy))
                         return ClangASTType (ast, ast->VoidTy.getAsOpaquePtr());
                     if (strstr(type_name, "long long") &&
                         QualTypeMatchesBitSize (bit_size, ast, ast->LongLongTy))
                         return ClangASTType (ast, ast->LongLongTy.getAsOpaquePtr());
                     if (strstr(type_name, "long") &&
if (ast)
                 }
                 if (QualTypeMatchesBitSize (bit_size, ast, ast->SignedCharTy))
                     return ClangASTType (ast, ast->SignedCharTy.getAsOpaquePtr());
                 break;
                 
             case DW_ATE_unsigned:
                 if (type_name)
                 {
+                    if (streq(type_name, "wchar_t"))
+                    {
+                        if (QualTypeMatchesBitSize (bit_size, ast, ast->WCharTy))
+                        {
+                            if (!TargetInfo::isTypeSigned (getTargetInfo()->getWCharType()))
+                                return ClangASTType (ast, ast->WCharTy.getAsOpaquePtr());
+                        }
+                    }
                     if (strstr(type_name, "long long"))
                     {
                         if (QualTypeMatchesBitSize (bit_size, ast, ast->UnsignedLongLongTy))
                             return ClangASTType (ast, ast->UnsignedLongLongTy.getAsOpaquePtr());
                     }
                     else if (strstr(type_name, "long"))
                     {
                         if (QualTypeMatchesBitSize (bit_size, ast, ast->UnsignedLongTy))