Add a bit to IdentifierInfo that acts as a simple predicate which
tells us whether Preprocessor::HandleIdentifier needs to be called.
Because this method is only rarely needed, this saves a call and a
bunch of random checks.  This drops the time in HandleIdentifier 
from 3.52ms to .98ms on cocoa.h on my machine.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@62675 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Lex/Preprocessor.cpp b/lib/Lex/Preprocessor.cpp
index 5d9fc95..e53c392 100644
--- a/lib/Lex/Preprocessor.cpp
+++ b/lib/Lex/Preprocessor.cpp
@@ -718,6 +718,11 @@
 /// HandleIdentifier - This callback is invoked when the lexer reads an
 /// identifier.  This callback looks up the identifier in the map and/or
 /// potentially macro expands it or turns it into a named token (like 'for').
+///
+/// Note that callers of this method are guarded by checking the
+/// IdentifierInfo's 'isHandleIdentifierCase' bit.  If this method changes, the
+/// IdentifierInfo methods that compute these properties will need to change to
+/// match.
 void Preprocessor::HandleIdentifier(Token &Identifier) {
   assert(Identifier.getIdentifierInfo() &&
          "Can't handle identifiers without identifier info!");