Support alternate attribute spelling __enable_if__

Attribute names usually support an alternate spelling that uses double
underscores before and after the attribute name, like e.g. attribute
((__aligned__)) for attribute ((aligned)). This is necessary to allow
use of attributes in system headers without polluting the name space.

However, for attribute ((enable_if)) that alternate spelling does not
work correctly. This is because of code in Parser::ParseGNUAttributeArgs
(ParseDecl.cpp) that specifically checks for the "enable_if" spelling
without allowing the alternate spelling.

Similar code in ParseDecl.cpp uses the normalizeAttrName helper to allow
both spellings. This patch adds use of that helper for the "enable_if"
check as well, which fixes attribute ((__enable_if__)).

Differential Revision: http://reviews.llvm.org/D11142

llvm-svn: 242029

1 files changed, 2 insertions, 1 deletions

diff --git a/clang/lib/Parse/ParseDecl.cpp b/clang/lib/Parse/ParseDecl.cpp
index bc253f7f861..f46af889e25 100644
--- a/clang/lib/Parse/ParseDecl.cpp
+++ b/clang/lib/Parse/ParseDecl.cpp
@@ -365,7 +365,8 @@ void Parser::ParseGNUAttributeArgs(IdentifierInfo *AttrName,
   // These may refer to the function arguments, but need to be parsed early to
   // participate in determining whether it's a redeclaration.
   std::unique_ptr<ParseScope> PrototypeScope;
-  if (AttrName->isStr("enable_if") && D && D->isFunctionDeclarator()) {
+  if (normalizeAttrName(AttrName->getName()) == "enable_if" &&
+      D && D->isFunctionDeclarator()) {
     DeclaratorChunk::FunctionTypeInfo FTI = D->getFunctionTypeInfo();
     PrototypeScope.reset(new ParseScope(this, Scope::FunctionPrototypeScope |
                                         Scope::FunctionDeclarationScope |