When parsing an identifier as an expression in C++, only try to annotate it
as a type or scope token if the next token requires it.
This eliminates a lot of redundant lookups in C++, but there's room for
improvement; a better solution would do a single lookup whose kind and
results would be passed through the parser.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@92930 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Parse/ParseExpr.cpp b/lib/Parse/ParseExpr.cpp
index bdbc67f..4d6988d 100644
--- a/lib/Parse/ParseExpr.cpp
+++ b/lib/Parse/ParseExpr.cpp
@@ -616,9 +616,17 @@
// Turn a potentially qualified name into a annot_typename or
// annot_cxxscope if it would be valid. This handles things like x::y, etc.
if (getLang().CPlusPlus) {
- // If TryAnnotateTypeOrScopeToken annotates the token, tail recurse.
- if (TryAnnotateTypeOrScopeToken())
- return ParseCastExpression(isUnaryExpression, isAddressOfOperand);
+ // Avoid the unnecessary parse-time lookup in the common case
+ // where the syntax forbids a type.
+ const Token &Next = NextToken();
+ if (Next.is(tok::coloncolon) ||
+ (!ColonIsSacred && Next.is(tok::colon)) ||
+ Next.is(tok::less) ||
+ Next.is(tok::l_paren)) {
+ // If TryAnnotateTypeOrScopeToken annotates the token, tail recurse.
+ if (TryAnnotateTypeOrScopeToken())
+ return ParseCastExpression(isUnaryExpression, isAddressOfOperand);
+ }
}
// Consume the identifier so that we can see if it is followed by a '(' or