From c85eface68940368f696807e97ac7d707e8a73eb Mon Sep 17 00:00:00 2001
From: "Jonathan M. Wilbur" <jonathan@wilbur.space>
Date: Tue, 30 Jul 2024 08:54:00 -0400
Subject: [PATCH] feat: treat unknown macros with arguments as undefined

---
 tccpp.c                  | 14 ++++++++++++++
 tests/undef_func_macro.c | 13 +++++++++++++
 2 files changed, 27 insertions(+)
 create mode 100644 tests/undef_func_macro.c

diff --git a/tccpp.c b/tccpp.c
index 6f2bc173..a59ba814 100644
--- a/tccpp.c
+++ b/tccpp.c
@@ -1506,6 +1506,20 @@ static int expr_preprocess(TCCState *s1)
             tokc.i = c;
         } else {
             /* if undefined macro, replace with zero */
+            next_nomacro();
+            // If the undefined macro is followed by parens, just skip them.
+            if (tok == '(') {
+                int bracket_depth = 1;
+                while (bracket_depth > 0) {
+                    next();
+                    if (tok == '(')
+                        bracket_depth++;
+                    else if (tok == ')')
+                        bracket_depth--;
+                }
+            } else {
+                unget_tok(tok); // Is this actually the function I want?
+            }
             tok = TOK_CINT;
             tokc.i = 0;
         }
diff --git a/tests/undef_func_macro.c b/tests/undef_func_macro.c
new file mode 100644
index 00000000..00db8ad0
--- /dev/null
+++ b/tests/undef_func_macro.c
@@ -0,0 +1,13 @@
+int main () {
+// This used to evaluate to 0 (0), which is invalid.
+// Now it should evaluate to 0.
+#if WUMBOED(WUMBO)
+#endif
+
+// Just trying a more complicated test case.
+#if WUMBO && defined(WUMBOLOGY) || WUMBOED(WUMBO) && !WUMBOLOGY
+    return 0;
+#elif WUMBO && defined(WUMBOLOGY) || WUMBOED(WUMBO) && !WUMBOLOGY
+    return 1;
+#endif
+}
-- 
2.11.4.GIT