1 files changed, 32 insertions, 12 deletions

diff --git a/clang/lib/Parse/ParseDeclCXX.cpp b/clang/lib/Parse/ParseDeclCXX.cpp
index 9369f0f56c9..c814775c77e 100644
--- a/clang/lib/Parse/ParseDeclCXX.cpp
+++ b/clang/lib/Parse/ParseDeclCXX.cpp
@@ -3790,6 +3790,28 @@ IdentifierInfo *Parser::TryParseCXX11AttributeIdentifier(SourceLocation &Loc) {
     }
     return nullptr;
 
+  case tok::numeric_constant: {
+    // If we got a numeric constant, check to see if it comes from a macro that
+    // corresponds to the predefined __clang__ macro. If it does, warn the user
+    // and recover by pretending they said _Clang instead.
+    if (Tok.getLocation().isMacroID()) {
+      SmallString<8> ExpansionBuf;
+      SourceLocation ExpansionLoc =
+          PP.getSourceManager().getExpansionLoc(Tok.getLocation());
+      StringRef Spelling = PP.getSpelling(ExpansionLoc, ExpansionBuf);
+      if (Spelling == "__clang__") {
+        SourceRange TokRange(
+            ExpansionLoc,
+            PP.getSourceManager().getExpansionLoc(Tok.getEndLoc()));
+        Diag(Tok, diag::warn_wrong_clang_attr_namespace)
+            << FixItHint::CreateReplacement(TokRange, "_Clang");
+        Loc = ConsumeToken();
+        return &PP.getIdentifierTable().get("_Clang");
+      }
+    }
+    return nullptr;
+  }
+
   case tok::ampamp:       // 'and'
   case tok::pipe:         // 'bitor'
   case tok::pipepipe:     // 'or'
@@ -3865,24 +3887,22 @@ bool Parser::ParseCXX11AttributeArgs(IdentifierInfo *AttrName,
     // Eat the left paren, then skip to the ending right paren.
     ConsumeParen();
     SkipUntil(tok::r_paren);
-    return false;

-  }

-

-  if (ScopeName &&

-      (ScopeName->getName() == "gnu" || ScopeName->getName() == "__gnu__")) {

-    // GNU-scoped attributes have some special cases to handle GNU-specific

-    // behaviors.

-    ParseGNUAttributeArgs(AttrName, AttrNameLoc, Attrs, EndLoc, ScopeName,

+    return false;
+  }
+
+  if (ScopeName && (ScopeName->isStr("gnu") || ScopeName->isStr("__gnu__"))) {
+    // GNU-scoped attributes have some special cases to handle GNU-specific
+    // behaviors.
+    ParseGNUAttributeArgs(AttrName, AttrNameLoc, Attrs, EndLoc, ScopeName,
                           ScopeLoc, Syntax, nullptr);
     return true;
   }
 
   unsigned NumArgs;
   // Some Clang-scoped attributes have some special parsing behavior.
-  if (ScopeName && ScopeName->getName() == "clang")
-    NumArgs =
-        ParseClangAttributeArgs(AttrName, AttrNameLoc, Attrs, EndLoc, ScopeName,
-                                ScopeLoc, Syntax);
+  if (ScopeName && (ScopeName->isStr("clang") || ScopeName->isStr("_Clang")))
+    NumArgs = ParseClangAttributeArgs(AttrName, AttrNameLoc, Attrs, EndLoc,
+                                      ScopeName, ScopeLoc, Syntax);
   else
     NumArgs =
         ParseAttributeArgsCommon(AttrName, AttrNameLoc, Attrs, EndLoc,