C#: Remove the JumpReturnKind and the related summary component stack.

Author: michaelnebel

csharp/ql/lib/semmle/code/csharp/dataflow/FlowSummary.qll

@@ -64,15 +64,6 @@ module SummaryComponent {
   /** Gets a summary component that represents the return value of a call. */
   SummaryComponent return() { result = return(any(DataFlowDispatch::NormalReturnKind rk)) }
 
-  /** Gets a summary component that represents a jump to `c`. */
-  SummaryComponent jump(Callable c) {
-    result =
-      return(any(DataFlowDispatch::JumpReturnKind jrk |
-          jrk.getTarget() = c.getUnboundDeclaration() and
-          jrk.getTargetReturnKind() instanceof DataFlowDispatch::NormalReturnKind
-        ))
-  }
-
   predicate syntheticGlobal = SummaryComponentInternal::syntheticGlobal/1;
 
   class SyntheticGlobal = SummaryComponentInternal::SyntheticGlobal;
@@ -114,9 +105,6 @@ module SummaryComponentStack {
   /** Gets a singleton stack representing the return value of a call. */
   SummaryComponentStack return() { result = singleton(SummaryComponent::return()) }
 
-  /** Gets a singleton stack representing a jump to `c`. */
-  SummaryComponentStack jump(Callable c) { result = singleton(SummaryComponent::jump(c)) }
-
   /** Gets a singleton stack representing a synthetic global with name `name`. */
   SummaryComponentStack syntheticGlobal(string synthetic) {
     result = singleton(SummaryComponent::syntheticGlobal(synthetic))

csharp/ql/lib/semmle/code/csharp/dataflow/internal/DataFlowDispatch.qll

@@ -74,18 +74,6 @@ newtype TReturnKind =
     exists(Ssa::ExplicitDefinition def | def.isCapturedVariableDefinitionFlowOut(_, _) |
       v = def.getSourceVariable().getAssignable()
     )
-  } or
-  TJumpReturnKind(Callable target, ReturnKind rk) {
-    target.isUnboundDeclaration() and
-    (
-      rk instanceof NormalReturnKind and
-      (
-        target instanceof Constructor or
-        not target.getReturnType() instanceof VoidType
-      )
-      or
-      exists(target.getParameter(rk.(OutRefReturnKind).getPosition()))
-    )
   }
 
 /**
@@ -257,27 +245,6 @@ class ImplicitCapturedReturnKind extends ReturnKind, TImplicitCapturedReturnKind
   override string toString() { result = "captured " + v }
 }
 
-/**
- * A value returned through the output of another callable.
- *
- * This is currently only used to model flow summaries where data may flow into
- * one API entry point and out of another.
- */
-class JumpReturnKind extends ReturnKind, TJumpReturnKind {
-  private Callable target;
-  private ReturnKind rk;
-
-  JumpReturnKind() { this = TJumpReturnKind(target, rk) }
-
-  /** Gets the target of the jump. */
-  Callable getTarget() { result = target }
-
-  /** Gets the return kind of the target. */
-  ReturnKind getTargetReturnKind() { result = rk }
-
-  override string toString() { result = "jump to " + target }
-}
-
 /** A callable used for data flow. */
 class DataFlowCallable extends TDataFlowCallable {
   /** Get the underlying source code callable, if any. */

csharp/ql/lib/semmle/code/csharp/dataflow/internal/DataFlowPrivate.qll

@@ -1457,8 +1457,7 @@ private module ReturnNodes {
     private ReturnKind rk;
 
     SummaryReturnNode() {
-      FlowSummaryImpl::Private::summaryReturnNode(this.getSummaryNode(), rk) and
-      not rk instanceof JumpReturnKind
+      FlowSummaryImpl::Private::summaryReturnNode(this.getSummaryNode(), rk)
       or
       exists(Parameter p, int pos |
         summaryPostUpdateNodeIsOutOrRef(this, p) and
@@ -1708,12 +1707,6 @@ predicate jumpStep(Node pred, Node succ) {
     flr.hasNonlocalValue()
   )
   or
-  exists(JumpReturnKind jrk, NonDelegateDataFlowCall call |
-    FlowSummaryImpl::Private::summaryReturnNode(pred.(FlowSummaryNode).getSummaryNode(), jrk) and
-    jrk.getTarget() = call.getATarget(_) and
-    succ = getAnOutNode(call, jrk.getTargetReturnKind())
-  )
-  or
   FlowSummaryImpl::Private::Steps::summaryJumpStep(pred.(FlowSummaryNode).getSummaryNode(),
     succ.(FlowSummaryNode).getSummaryNode())
 }

csharp/ql/lib/semmle/code/csharp/dataflow/internal/FlowSummaryImplSpecific.qll

@@ -61,7 +61,7 @@ DataFlowType getParameterType(SummarizedCallable c, ParameterPosition pos) {
   )
 }
 
-private DataFlowType getReturnTypeBase(DotNet::Callable c, ReturnKind rk) {
+DataFlowType getReturnType(DotNet::Callable c, ReturnKind rk) {
   exists(Type t | result = Gvn::getGlobalValueNumber(t) |
     rk instanceof NormalReturnKind and
     (
@@ -75,15 +75,6 @@ private DataFlowType getReturnTypeBase(DotNet::Callable c, ReturnKind rk) {
   )
 }
 
-/** Gets the return type of kind `rk` for callable `c`. */
-bindingset[c]
-DataFlowType getReturnType(SummarizedCallable c, ReturnKind rk) {
-  result = getReturnTypeBase(c, rk)
-  or
-  rk =
-    any(JumpReturnKind jrk | result = getReturnTypeBase(jrk.getTarget(), jrk.getTargetReturnKind()))
-}
-
 /**
  * Gets the type of the parameter matching arguments at position `pos` in a
  * synthesized call that targets a callback of type `t`.