[clang] [Parser][BoundsSafety] Print attribute as macro if it's system defined (PR #107619)

[Aaron Ballman via cfe-commits]

================
@@ -835,6 +835,17 @@ void Parser::ParseLexedAttribute(LateParsedAttribute &LA,
     Diag(Tok, diag::warn_attribute_on_function_definition)
       << &LA.AttrName;
 
+  const auto &SM = PP.getSourceManager();
+  CharSourceRange ExpansionRange = SM.getExpansionRange(LA.AttrNameLoc);
+  StringRef FoundName =
+      Lexer::getSourceText(ExpansionRange, SM, PP.getLangOpts())
+          .split('(')
+          .first;
+  IdentifierInfo *MacroII = PP.getIdentifierInfo(FoundName);
----------------
AaronBallman wrote:

What if no name is found?

https://github.com/llvm/llvm-project/pull/107619