Implement the NoBuiltin attribute.

The 'nobuiltin' attribute is applied to call sites to indicate that LLVM should
not treat the callee function as a built-in function. I.e., it shouldn't try to
replace that function with different code.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@175835 91177308-0d34-0410-b5e6-96231b3b80d8

lib/AsmParser/LLLexer.cpp

@@ -571,6 +571,7 @@ lltok::Kind LLLexer::LexIdentifier() {
   KEYWORD(naked);
   KEYWORD(nest);
   KEYWORD(noalias);
+  KEYWORD(nobuiltin);
   KEYWORD(nocapture);
   KEYWORD(noduplicate);
   KEYWORD(noimplicitfloat);