JS: Add debug tools for detecting lost nodes/edges

Author: New Product Launch Poster For Drugs

javascript/ql/lib/semmle/javascript/ApiGraphs.qll

@@ -819,7 +819,7 @@ module API {
  * Holds if `rhs` is the right-hand side of a definition of a node that should have an
  * incoming edge from `base` labeled `lbl` in the API graph.
  */
- private predicate rhs(TApiNode base, Label::ApiLabel lbl, DataFlow::Node rhs) {
+ predicate rhs(TApiNode base, Label::ApiLabel lbl, DataFlow::Node rhs) {
  hasSemantics(rhs) and
  (
  base = MkRoot() and
@@ -1058,7 +1058,7 @@ module API {
  * Holds if `ref` is a use of a node that should have an incoming edge from `base` labeled
  * `lbl` in the API graph.
  */
- private predicate use(TApiNode base, Label::ApiLabel lbl, DataFlow::Node ref) {
+ predicate use(TApiNode base, Label::ApiLabel lbl, DataFlow::Node ref) {
  hasSemantics(ref) and
  (
  base = MkRoot() and
@@ -1706,6 +1706,43 @@ module API {
 
  import Cached
 
+ private module Debug {
+ private module FullInput implements StageInputSig {
+ pragma[inline]
+ predicate isAdditionalUseRoot(Node node) { none() }
+
+ pragma[inline]
+ predicate isAdditionalDefRoot(Node node) { none() }
+
+ bindingset[node]
+ predicate inScope(DataFlow::Node node) { any() }
+ }
+
+ private module Full = Stage<FullInput>;
+
+ query predicate missingDefNode(DataFlow::Node node) {
+ Full::rhs(_, _, node) and
+ not exists(MkDef(node))
+ }
+
+ query predicate missingUseNode(DataFlow::Node node) {
+ Full::use(_, _, node) and
+ not exists(MkUse(node))
+ }
+
+ query predicate lostEdge(Node pred, Label::ApiLabel lbl, Node succ) {
+ Full::edge(pred, lbl, succ) and
+ not Cached::edge(pred, lbl, succ)
+ }
+
+ query predicate counts(int numEdges, int numOverlayEdges, float ratio) {
+ numEdges = count(Node pred, Label::ApiLabel lbl, Node succ | Full::edge(pred, lbl, succ)) and
+ numOverlayEdges =
+ count(Node pred, Label::ApiLabel lbl, Node succ | Stage2::edge(pred, lbl, succ)) and
+ ratio = numOverlayEdges / numEdges.(float)
+ }
+ }
+
  /**
  * Holds if there is an edge from `pred` to `succ` in the API graph.
  */