Turn off __has_feature(cxx_rtti) when -fno-rtti-data is present

-fno-rtti-data makes it so that vtables emitted in the current TU lack
RTTI data. This means that dynamic_cast usually fails at runtime. Users
of the existing cxx_rtti feature expect all of RTTI to work, not just
some of it.

Chromium bug for context: http://crbug.com/518191

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@244922 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Lex/PPMacroExpansion.cpp

@@ -1076,7 +1076,7 @@ static bool HasFeature(const Preprocessor &PP, const IdentifierInfo *II) {
       .Case("blocks", LangOpts.Blocks)
       .Case("c_thread_safety_attributes", true)
       .Case("cxx_exceptions", LangOpts.CXXExceptions)
-      .Case("cxx_rtti", LangOpts.RTTI)
+      .Case("cxx_rtti", LangOpts.RTTI && LangOpts.RTTIData)
       .Case("enumerator_attributes", true)
       .Case("nullability", true)
       .Case("memory_sanitizer", LangOpts.Sanitize.has(SanitizerKind::Memory))

test/Lexer/has_feature_rtti.cpp

@@ -1,5 +1,6 @@
 // RUN: %clang_cc1 -E %s -o - | FileCheck --check-prefix=CHECK-RTTI %s
 // RUN: %clang_cc1 -E -fno-rtti %s -o - | FileCheck --check-prefix=CHECK-NO-RTTI %s
+// RUN: %clang_cc1 -E -fno-rtti-data %s -o - | FileCheck --check-prefix=CHECK-NO-RTTI %s
 
 #if __has_feature(cxx_rtti)
 int foo();