JS: Refactor toDataFlowNode

Author: asgerf

javascript/ql/lib/semmle/javascript/dataflow/internal/CallGraphs.qll

@@ -14,7 +14,7 @@ module CallGraph {
   Function getAFunctionValue(AnalyzedNode node) {
     result = node.getAValue().(AbstractCallable).getFunction()
     or
-    node = NameResolution::trackFunctionValue(result).toDataFlowNode()
+    node = NameResolution::trackFunctionValue(result).toDataFlowNodeOut()
     or
     exists(DataFlow::Node pred |
       AccessPath::step(pred, node) and

javascript/ql/lib/semmle/javascript/dataflow/internal/FlowSteps.qll

@@ -336,13 +336,13 @@ private module CachedSteps {
     // TODO: Ensure name resolution has good enough support for NodeJS and AMD
     exists(NameResolution::Node node1, NameResolution::Node node2 |
       NameResolution::ValueFlow::resolvedReadStep(node1, node2) and
-      pred = node1.toDataFlowNode() and
-      succ = node2.toDataFlowNode()
+      pred = node1.toDataFlowNodeIn() and
+      succ = node2.toDataFlowNodeOut()
     )
     or
     exists(Import imprt, Module mod |
       imprt.getImportedModule() = mod and
-      pred = NameResolution::getModuleBulkExport(mod).toDataFlowNode() and
+      pred = NameResolution::getModuleBulkExport(mod).toDataFlowNodeIn() and
       succ = imprt.getImportedModuleNodeStrict()
     )
   }

javascript/ql/lib/semmle/javascript/internal/NameResolution.qll

@@ -35,19 +35,21 @@ module NameResolution {
       result = this.(JSDocTypeExpr).getLocation()
     }
 
-    DataFlow::Node toDataFlowNode() {
+    DataFlow::Node toDataFlowNodeIn() {
       result = DataFlow::valueNode(this)
       or
-      // TODO: refactor graph to avoid the need for this
+      result = DataFlow::valueNode(this.(Variable).getAnAssignedExpr())
+    }
+
+    DataFlow::Node toDataFlowNodeOut() {
+      result = DataFlow::valueNode(this)
+      or
+      result = DataFlow::valueNode(this.(Variable).getAnAccess())
+      or
       exists(ImportSpecifier spec |
         this = spec.getLocal() and
         result = DataFlow::valueNode(spec)
       )
-      or
-      exists(ExportDeclaration exprt, string name |
-        exprt.exportsAs(this, name) and
-        result = exprt.getSourceNode(name)
-      )
     }
   }