Add witness_assert_depth[_to_rank]().

This makes it possible to make lock state assertions about precisely
which locks are held.

include/jemalloc/internal/private_symbols.txt

@@ -549,13 +549,15 @@ tsdn_fetch
 tsdn_null
 tsdn_rtree_ctx
 tsdn_tsd
+witness_assert_depth
+witness_assert_depth_to_rank
 witness_assert_lockless
 witness_assert_not_owner
 witness_assert_owner
+witness_depth_error
 witness_init
 witness_lock
 witness_lock_error
-witness_lockless_error
 witness_not_owner_error
 witness_owner
 witness_owner_error

include/jemalloc/internal/witness_externs.h

@@ -23,10 +23,12 @@ extern witness_not_owner_error_t *witness_not_owner_error;
 void	witness_not_owner_error(const witness_t *witness);
 #endif
 #ifdef JEMALLOC_JET
-typedef void (witness_lockless_error_t)(const witness_list_t *);
-extern witness_lockless_error_t *witness_lockless_error;
+typedef void (witness_depth_error_t)(const witness_list_t *,
+    witness_rank_t rank_inclusive, unsigned depth);
+extern witness_depth_error_t *witness_depth_error;
 #else
-void	witness_lockless_error(const witness_list_t *witnesses);
+void	witness_depth_error(const witness_list_t *witnesses,
+    witness_rank_t rank_inclusive, unsigned depth);
 #endif
 
 void	witnesses_cleanup(tsd_t *tsd);

include/jemalloc/internal/witness_inlines.h

@@ -5,6 +5,9 @@
 bool	witness_owner(tsd_t *tsd, const witness_t *witness);
 void	witness_assert_owner(tsdn_t *tsdn, const witness_t *witness);
 void	witness_assert_not_owner(tsdn_t *tsdn, const witness_t *witness);
+void witness_assert_depth_to_rank(tsdn_t *tsdn, witness_rank_t rank_inclusive,
+    unsigned depth);
+void witness_assert_depth(tsdn_t *tsdn, unsigned depth);
 void	witness_assert_lockless(tsdn_t *tsdn);
 void	witness_lock(tsdn_t *tsdn, witness_t *witness);
 void	witness_unlock(tsdn_t *tsdn, witness_t *witness);
@@ -78,8 +81,10 @@ witness_assert_not_owner(tsdn_t *tsdn, const witness_t *witness) {
 }
 
 JEMALLOC_INLINE void
-witness_assert_lockless(tsdn_t *tsdn) {
+witness_assert_depth_to_rank(tsdn_t *tsdn, witness_rank_t rank_inclusive,
+    unsigned depth) {
 	tsd_t *tsd;
+	unsigned d;
 	witness_list_t *witnesses;
 	witness_t *w;
 
@@ -92,11 +97,30 @@ witness_assert_lockless(tsdn_t *tsdn) {
 	}
 	tsd = tsdn_tsd(tsdn);
 
+	d = 0;
 	witnesses = tsd_witnessesp_get(tsd);
 	w = ql_last(witnesses, link);
 	if (w != NULL) {
-		witness_lockless_error(witnesses);
+		ql_reverse_foreach(w, witnesses, link) {
+			if (w->rank < rank_inclusive) {
+				break;
+			}
+			d++;
+		}
 	}
+	if (d != depth) {
+		witness_depth_error(witnesses, rank_inclusive, depth);
+	}
+}
+
+JEMALLOC_INLINE void
+witness_assert_depth(tsdn_t *tsdn, unsigned depth) {
+	witness_assert_depth_to_rank(tsdn, WITNESS_RANK_MIN, depth);
+}
+
+JEMALLOC_INLINE void
+witness_assert_lockless(tsdn_t *tsdn) {
+	witness_assert_depth(tsdn, 0);
 }
 
 JEMALLOC_INLINE void

include/jemalloc/internal/witness_types.h

@@ -13,6 +13,8 @@ typedef int witness_comp_t (const witness_t *, void *, const witness_t *,
  */
 #define WITNESS_RANK_OMIT		0U
 
+#define WITNESS_RANK_MIN		1U
+
 #define WITNESS_RANK_INIT		1U
 #define WITNESS_RANK_CTL		1U
 #define WITNESS_RANK_ARENAS		2U