[PATCH smatch-devel 4/5] smatch: add passed-to debug helper

Add __smatch_passed_to() to check_debug so validation and developers can
print the linked call history for a variable expression.

Cover sequential calls using different argument positions and verify the
reported $N indexes.

Assisted-by: Codex:5.6
Signed-off-by: Harshit Mogalapalli <[email protected]>
---
 check_debug.c             |  9 +++++++++
 check_debug.h             |  3 +++
 validation/sm_passed_to.c | 21 +++++++++++++++++++++
 3 files changed, 33 insertions(+)
 create mode 100644 validation/sm_passed_to.c

diff --git a/check_debug.c b/check_debug.c
index 30b9e617ca5d..59970412a491 100644
--- a/check_debug.c
+++ b/check_debug.c
@@ -782,6 +782,14 @@ static void match_about(const char *fn, struct expression *expr, void *info)
 	debug_print_about(arg);
 }
 
+static void match_passed_to(const char *fn, struct expression *expr, void *info)
+{
+	struct expression *arg;
+
+	arg = get_check_arg(expr, 0);
+	print_passed_to(arg);
+}
+
 static void match_intersection(const char *fn, struct expression *expr, void *info)
 {
 	struct expression *one, *two;
@@ -1173,6 +1181,7 @@ void check_debug(int id)
 	my_id = id;
 
 	add_function_hook("__smatch_about", &match_about, NULL);
+	add_function_hook("__smatch_passed_to", &match_passed_to, NULL);
 	add_function_hook("__smatch_all_values", &match_all_values, NULL);
 	add_function_hook("__smatch_state", &match_state, NULL);
 	add_function_hook("__smatch_states", &match_states, NULL);
diff --git a/check_debug.h b/check_debug.h
index 59714b7b82ab..5758919059cf 100644
--- a/check_debug.h
+++ b/check_debug.h
@@ -6,6 +6,9 @@
 static inline void __smatch_about(long var){}
 #define __smatch_about(x) __smatch_about(cast_ptr(x))
 
+static inline void __smatch_passed_to(long var){}
+#define __smatch_passed_to(x) __smatch_passed_to(cast_ptr(x))
+
 static inline void __smatch_cur_stree(void){}
 static inline void __smatch_all_values(void){}
 static inline void __smatch_state(const char *check_name, const char *state_name){}
diff --git a/validation/sm_passed_to.c b/validation/sm_passed_to.c
new file mode 100644
index 000000000000..57c284f96e22
--- /dev/null
+++ b/validation/sm_passed_to.c
@@ -0,0 +1,21 @@
+#include "check_debug.h"
+
+void first(int ignored, int value);
+void second(int value);
+
+void func(int value)
+{
+	first(0, value);
+	second(value);
+	__smatch_passed_to(value);
+}
+
+/*
+ * check-name: smatch passed to
+ * check-command: smatch -I.. sm_passed_to.c
+ *
+ * check-output-start
+sm_passed_to.c:10 func() passed to first $1
+sm_passed_to.c:10 func() passed to second $0
+ * check-output-end
+ */
-- 
2.52.0