[PATCH] D17149: Consolidate and improve the handling of built-in feature-like macros

[Richard Smith via cfe-commits]

rsmith added inline comments.

================
Comment at: lib/Lex/PPMacroExpansion.cpp:1430-1432
@@ +1429,5 @@
+                                            Preprocessor &PP,
+                                            int(*Op)(Token &Tok,
+                                                     Preprocessor &PP,
+                                                     bool &HasLexedNextTok)) {
+  // Parse the initial '('.
----------------
Use `llvm::function_ref` here instead, and don't pass a `Preprocessor` into the function (instead, capture it in a lambda).

================
Comment at: lib/Lex/PPMacroExpansion.cpp:1456-1457
@@ +1455,4 @@
+
+    // Parse next non-comment, non-annotation token.
+    do PP.LexUnexpandedNonComment(Tok); while (Tok.isAnnotation());
+
----------------
If we get an annotation token here, we should reject it, not silently ignore it. Also, we shouldn't see comment tokens here (we shouldn't be doing macro expansion with comments enabled); you should call `LexUnexpandedToken` rather than `LexUnexpandedNonComment`.

================
Comment at: lib/Lex/PPMacroExpansion.cpp:1481-1484
@@ +1480,6 @@
+          auto Diag = PP.Diag(Tok.getLocation(), diag::err_pp_unexpected_after);
+          if (IdentifierInfo *LastII = LastTok.getIdentifierInfo())
+            Diag << LastII;
+          else
+            Diag << LastTok.getKind();
+          Diag << tok::l_paren << LastTok.getLocation();
----------------
The only way we can get here without already having a value or producing a diagnostic is if this is the first token inside the parens. So this will always say "unexpected '(' after '('".

I think it would be better to always `break` here after incrementing `ParenDepth` (even when `!Result.hasValue()`), and let `Op` produce the relevant diagnostic for this case.

================
Comment at: lib/Lex/PPMacroExpansion.cpp:1519
@@ +1518,3 @@
+
+    // Diagnose expected ')'.
+    if (!SuppressDiagnostic) {
----------------
expected -> missing


http://reviews.llvm.org/D17149