Python: remove NonLibraryNormalCall

yoff · yoff · commit fa2da2f3ecff · 2022-09-11T22:25:29.000+02:00
it is not necessary to distinguish these calls,
so we remove the class from the hierarchy.
diff --git a/python/ql/lib/semmle/python/dataflow/new/internal/DataFlowDispatchPointsTo.qll b/python/ql/lib/semmle/python/dataflow/new/internal/DataFlowDispatchPointsTo.qll
@@ -103,10 +103,10 @@ module ArgumentPassing {
    * Used to limit the size of predicates.
    */
   predicate connects(CallNode call, CallableValue callable) {
-    exists(NonLibraryNormalCall c, NonLibraryDataFlowCallable k |
+    exists(NormalCall c, NonLibraryDataFlowCallable k |
       call = c.getNode() and
       callable = k.getCallableValue() and
-      k = c.getNonLibraryCallable()
+      k = c.getCallable()
     )
   }
 
@@ -511,81 +511,64 @@ class NormalCall extends DataFlowSourceCall, TNormalCall {
 
   abstract override Node getArg(int n);
 
-  override ControlFlowNode getNode() { result = call }
+  override CallNode getNode() { result = call }
 
   abstract override DataFlowCallable getCallable();
 
   override DataFlowCallable getEnclosingCallable() { result.getScope() = call.getNode().getScope() }
 }
 
-/** A (non-special) call that does not go to a library callable. */
-abstract class NonLibraryNormalCall extends NormalCall {
-  abstract Node getNonLibraryArg(int n);
-
-  final override Node getArg(int n) { result = this.getNonLibraryArg(n) }
-
-  abstract DataFlowCallable getNonLibraryCallable();
-
-  final override DataFlowCallable getCallable() { result = this.getNonLibraryCallable() }
-}
-
 /**
  * A call to a function.
  * This excludes calls to bound methods, classes, and special methods.
  * Bound method calls and class calls insert an argument for the explicit
  * `self` parameter, and special method calls have special argument passing.
  */
-class FunctionCall extends NonLibraryNormalCall {
+class FunctionCall extends NormalCall {
   NonLibraryDataFlowCallable callable;
 
   FunctionCall() {
     call = any(FunctionValue f).getAFunctionCall() and
     call = callable.getACall()
   }
 
-  override Node getNonLibraryArg(int n) {
-    result = getArg(call, TNoShift(), callable.getCallableValue(), n)
-  }
+  override Node getArg(int n) { result = getArg(call, TNoShift(), callable.getCallableValue(), n) }
 
-  override DataFlowCallable getNonLibraryCallable() { result = callable }
+  override DataFlowCallable getCallable() { result = callable }
 }
 
 /** A call to a lambda. */
-class LambdaCall extends NonLibraryNormalCall {
+class LambdaCall extends NormalCall {
   NonLibraryDataFlowCallable callable;
 
   LambdaCall() {
     call = callable.getACall() and
     callable = TLambda(any(Function f))
   }
 
-  override Node getNonLibraryArg(int n) {
-    result = getArg(call, TNoShift(), callable.getCallableValue(), n)
-  }
+  override Node getArg(int n) { result = getArg(call, TNoShift(), callable.getCallableValue(), n) }
 
-  override DataFlowCallable getNonLibraryCallable() { result = callable }
+  override DataFlowCallable getCallable() { result = callable }
 }
 
 /**
  * Represents a call to a bound method call.
  * The node representing the instance is inserted as argument to the `self` parameter.
  */
-class MethodCall extends NonLibraryNormalCall {
+class MethodCall extends NormalCall {
   FunctionValue bm;
 
   MethodCall() { call = bm.getAMethodCall() }
 
   private CallableValue getCallableValue() { result = bm }
 
-  override Node getNonLibraryArg(int n) {
+  override Node getArg(int n) {
     n > 0 and result = getArg(call, TShiftOneUp(), this.getCallableValue(), n)
     or
     n = 0 and result = TCfgNode(call.getFunction().(AttrNode).getObject())
   }
 
-  override DataFlowCallable getNonLibraryCallable() {
-    result = TCallableValue(this.getCallableValue())
-  }
+  override DataFlowCallable getCallable() { result = TCallableValue(this.getCallableValue()) }
 }
 
 /**
@@ -594,7 +577,7 @@ class MethodCall extends NonLibraryNormalCall {
  * That makes the call node be the post-update node holding the value of the object
  * after the constructor has run.
  */
-class ClassCall extends NonLibraryNormalCall {
+class ClassCall extends NormalCall {
   ClassValue c;
 
   ClassCall() {
@@ -604,15 +587,13 @@ class ClassCall extends NonLibraryNormalCall {
 
   private CallableValue getCallableValue() { c.getScope().getInitMethod() = result.getScope() }
 
-  override Node getNonLibraryArg(int n) {
+  override Node getArg(int n) {
     n > 0 and result = getArg(call, TShiftOneUp(), this.getCallableValue(), n)
     or
     n = 0 and result = TSyntheticPreUpdateNode(TCfgNode(call))
   }
 
-  override DataFlowCallable getNonLibraryCallable() {
-    result = TCallableValue(this.getCallableValue())
-  }
+  override DataFlowCallable getCallable() { result = TCallableValue(this.getCallableValue()) }
 }
 
 /** A call to a special method. */
diff --git a/python/ql/lib/semmle/python/dataflow/new/internal/DataFlowPrivate.qll b/python/ql/lib/semmle/python/dataflow/new/internal/DataFlowPrivate.qll
@@ -137,15 +137,15 @@ module SyntheticPostUpdateNode {
    * and should not have an extra node synthesised.
    */
   Node argumentPreUpdateNode() {
-    result = any(FunctionCall c).getNonLibraryArg(_)
+    result = any(FunctionCall c).getArg(_)
     or
     // Avoid argument 0 of method calls as those have read post-update nodes.
-    exists(MethodCall c, int n | n > 0 | result = c.getNonLibraryArg(n))
+    exists(MethodCall c, int n | n > 0 | result = c.getArg(n))
     or
     result = any(SpecialCall c).getArg(_)
     or
     // Avoid argument 0 of class calls as those have non-synthetic post-update nodes.
-    exists(ClassCall c, int n | n > 0 | result = c.getNonLibraryArg(n))
+    exists(ClassCall c, int n | n > 0 | result = c.getArg(n))
     or
     // any argument of any call that we have not been able to resolve
     exists(CallNode call | not resolvedCall(call) |
diff --git a/python/ql/lib/semmle/python/dataflow/new/internal/FlowSummaryImplSpecific.qll b/python/ql/lib/semmle/python/dataflow/new/internal/FlowSummaryImplSpecific.qll
@@ -11,15 +11,20 @@
  *   These are identified by strings and has predicates for finding calls to them.
  *
  * Having both extracted and non-extracted callables means that we now have three types of calls:
- * - Extracted calls to extracted callables, either `NonLibraryNormalCall` or `SpecialCall`. These are handled by standard data flow.
- * - Extracted calls to non-extracted callables, `LibraryCall`. These are handled by summaries.
+ * - Extracted calls to extracted callables, either `NormalCall` or `SpecialCall`. These are handled by standard data flow.
+ * - Extracted calls to non-extracted callables, `LibraryCall`. These are handled by loking up the relevant summary when the
+ *   global data flwo graph is connected up via `getViableCallable`.
  * - Non-extracted calls, `SummaryCall`. These are synthesised by the flow summary framework.
  *
- * The first two can be referred to as `DataFlowSourceCall`. They have been split up for the benefit of call resolutiuon.
+ * The first two can be referred to as `DataFlowSourceCall`. In fact, `LibraryCall` is a subclass of `NormalCall`, where
+ * `getCallable` is set to `none()`. The member predicate `DataFlowSourceCall::getCallable` is _not_ the mechanism for
+ * call resolution in global data flow. That mechanism is `getViableCallable`.
  * Resolving a call to a non-extracted callable goes via `LibraryCallable::getACall`, which may involve type tracking.
  * To avoid that type tracking becomes mutualy recursive with data flow, type tracking must use a call graph not including summaries.
+ * Type tracking sees the callgraph given by `DataFlowSourceCall::getACallable`.
  *
- * We do not support summaries of special methods.
+ * We do not support summaries of special methods via the special methods framework,
+ * the summary would have to identify the call.
  */
 
 private import python
