implement __has_feature(address_sanitizer)

lib/Lex/PPMacroExpansion.cpp

 //===--- MacroExpansion.cpp - Top level Macro Expansion -------------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 // This file implements the top level handling of macro expasion for the
@@ skipping 565 matching lines @@
   TIMELoc = TmpTok.getLocation();
 }
 
 
 /// HasFeature - Return true if we recognize and implement the feature
 /// specified by the identifier as a standard language feature.
 static bool HasFeature(const Preprocessor &PP, const IdentifierInfo *II) {
   const LangOptions &LangOpts = PP.getLangOptions();
 
   return llvm::StringSwitch<bool>(II->getName())
+           .Case("address_sanitizer", LangOpts.AddressSanitizer)
            .Case("attribute_analyzer_noreturn", true)
            .Case("attribute_availability", true)
            .Case("attribute_cf_returns_not_retained", true)
            .Case("attribute_cf_returns_retained", true)
            .Case("attribute_deprecated_with_message", true)
            .Case("attribute_ext_vector_type", true)
            .Case("attribute_ns_returns_not_retained", true)
            .Case("attribute_ns_returns_retained", true)
            .Case("attribute_ns_consumes_self", true)
            .Case("attribute_ns_consumed", true)
@@ skipping 507 matching lines @@
                Tok.getLocation(), Tok.getLocation());
 }
 
 void Preprocessor::markMacroAsUsed(MacroInfo *MI) {
   // If the 'used' status changed, and the macro requires 'unused' warning,
   // remove its SourceLocation from the warn-for-unused-macro locations.
   if (MI->isWarnIfUnused() && !MI->isUsed())
     WarnUnusedMacroLocs.erase(MI->getDefinitionLoc());
   MI->setIsUsed(true);
 }