[LTP] [PATCH] check: Deprecated API symbols

[Richard Palethorpe]

The old API represents a big source of complication. It invalidates a
lot of assumptions we can make when writing checks specifically for
the new API.

Cyril proposed ignoring these symbols altogether in a previous
patch. This is a counter proposal to print a warning, but then abandon
checking the symbol any further.

The reasoning is that ignoring them altogether might hide errors. Also
the existence of the old API may be a surprise to new developers. This
change will alert them that a test needs updating and that it is not
to be used as a reference.

Signed-off-by: Richard Palethorpe <rpalethorpe@suse.com>
---
 tools/sparse/sparse-ltp.c | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/tools/sparse/sparse-ltp.c b/tools/sparse/sparse-ltp.c
index 3a38229f1..513033518 100644
--- a/tools/sparse/sparse-ltp.c
+++ b/tools/sparse/sparse-ltp.c
@@ -81,6 +81,32 @@ static void do_entrypoint_checks(struct entrypoint *ep)
 		do_basicblock_checks(bb);
 	} END_FOR_EACH_PTR(bb);
 }
+/* The old API can not comply with the rules. So when we see one of
+ * these symbols we know that it will result in further
+ * warnings. Probably these will suggest inappropriate things. Usually
+ * these symbols should be removed and the new API used
+ * instead. Otherwise they can be ignored until all tests have been
+ * converted to the new API.
+ */
+static bool check_symbol_deprecated(const struct symbol *const sym)
+{
+	static struct ident *TCID_id, *TST_TOTAL_id;
+	const struct ident *id = sym->ident;
+
+	if (!TCID_id) {
+		TCID_id = built_in_ident("TCID");
+		TST_TOTAL_id = built_in_ident("TST_TOTAL");
+	}
+
+	if (id != TCID_id && id != TST_TOTAL_id)
+		return false;
+
+	warning(sym->pos,
+		"Ignoring deprecated API symbol: '%s'. Should this code be converted to the new API?",
+		show_ident(id));
+
+	return true;
+}
 
 /* Check for LTP-003 and LTP-004
  *
@@ -212,6 +238,9 @@ static void check_test_struct(const struct symbol *const sym)
 /* AST level checks */
 static void do_symbol_checks(struct symbol *sym)
 {
+	if (check_symbol_deprecated(sym))
+		return;
+
 	check_symbol_visibility(sym);
 	check_test_struct(sym);
 }
-- 
2.34.0