Swift: Adopt shared ConditionalCompletionSplitting implementation

swift/ql/lib/codeql/swift/controlflow/internal/ControlFlowGraphImplSpecific.qll

@@ -46,10 +46,6 @@ module CfgInput implements InputSig<Location> {
 
   CfgScope getCfgScope(AstNode n) { result = scopeOfAst(n.asAstNode()) }
 
-  class SplitKindBase = Splitting::TSplitKind;
-
-  class Split = Splitting::Split;
-
   class SuccessorType = Cfg::SuccessorType;
 
   /** Gets a successor type that matches completion `c`. */
@@ -88,4 +84,19 @@ module CfgInput implements InputSig<Location> {
   }
 }
 
-module CfgImpl = Make<Location, CfgInput>;
+private module CfgSplittingInput implements SplittingInputSig<Location, CfgInput> {
+  private import Splitting as S
+
+  class SplitKindBase = S::TSplitKind;
+
+  class Split = S::Split;
+}
+
+private module ConditionalCompletionSplittingInput implements
+  ConditionalCompletionSplittingInputSig<Location, CfgInput, CfgSplittingInput>
+{
+  import Splitting::ConditionalCompletionSplitting::ConditionalCompletionSplittingInput
+}
+
+module CfgImpl =
+  MakeWithSplitting<Location, CfgInput, CfgSplittingInput, ConditionalCompletionSplittingInput>;

swift/ql/lib/codeql/swift/controlflow/internal/Splitting.qll

@@ -26,7 +26,7 @@ class Split extends TSplit {
   string toString() { none() }
 }
 
-private module ConditionalCompletionSplitting {
+module ConditionalCompletionSplitting {
   /** A split for conditional completions. */
   class ConditionalCompletionSplit extends Split, TConditionalCompletionSplit {
     ConditionalCompletion completion;
@@ -38,7 +38,7 @@ private module ConditionalCompletionSplitting {
     override string toString() { result = completion.toString() }
   }
 
-  private class ConditionalCompletionSplitKind extends SplitKind, TConditionalCompletionSplitKind {
+  private class ConditionalCompletionSplitKind_ extends SplitKind, TConditionalCompletionSplitKind {
     override int getListOrder() { result = 0 }
 
     override predicate isEnabled(ControlFlowElement n) { this.appliesTo(n) }
@@ -46,54 +46,44 @@ private module ConditionalCompletionSplitting {
     override string toString() { result = "ConditionalCompletion" }
   }
 
-  private class ConditionalCompletionSplitImpl extends SplitImpl instanceof ConditionalCompletionSplit
-  {
-    override ConditionalCompletionSplitKind getKind() { any() }
+  module ConditionalCompletionSplittingInput {
+    private import Completion as Comp
 
-    override predicate hasEntry(ControlFlowElement pred, ControlFlowElement succ, Completion c) {
-      succ(pred, succ, c) and
-      last(succ, _, super.getCompletion()) and
+    class ConditionalCompletion = Comp::ConditionalCompletion;
+
+    class ConditionalCompletionSplitKind extends ConditionalCompletionSplitKind_, TSplitKind { }
+
+    class ConditionalCompletionSplit = ConditionalCompletionSplitting::ConditionalCompletionSplit;
+
+    bindingset[parent, parentCompletion]
+    private predicate condPropagateAstExpr(
+      AstNode parent, ConditionalCompletion parentCompletion, AstNode child,
+      ConditionalCompletion childCompletion
+    ) {
+      child = parent.(NotExpr).getOperand().getFullyConverted() and
+      childCompletion.(BooleanCompletion).getDual() = parentCompletion
+      or
+      childCompletion = parentCompletion and
       (
-        astLast(succ.asAstNode().(NotExpr).getOperand().getFullyConverted(), pred, c) and
-        super.getCompletion().(BooleanCompletion).getDual() = c
+        child = parent.(LogicalAndExpr).getAnOperand().getFullyConverted()
         or
-        astLast(succ.asAstNode().(LogicalAndExpr).getAnOperand().getFullyConverted(), pred, c) and
-        super.getCompletion() = c
+        child = parent.(LogicalOrExpr).getAnOperand().getFullyConverted()
         or
-        astLast(succ.asAstNode().(LogicalOrExpr).getAnOperand().getFullyConverted(), pred, c) and
-        super.getCompletion() = c
+        child = parent.(IfExpr).getBranch(_).getFullyConverted()
         or
-        succ.asAstNode() =
-          any(IfExpr ce |
-            astLast(ce.getBranch(_).getFullyConverted(), pred, c) and
-            super.getCompletion() = c
-          )
-        or
-        exists(Expr e, Exprs::Conversions::ConversionOrIdentityTree conv |
-          succ.asAstNode() = conv.getAst() and
-          conv.convertsFrom(e) and
-          astLast(e, pred, c) and
-          super.getCompletion() = c
+        exists(Exprs::Conversions::ConversionOrIdentityTree conv |
+          parent = conv.getAst() and
+          conv.convertsFrom(child)
         )
       )
     }
 
-    override predicate hasEntryScope(CfgInput::CfgScope scope, ControlFlowElement succ) { none() }
-
-    override predicate hasExit(ControlFlowElement pred, ControlFlowElement succ, Completion c) {
-      this.appliesTo(pred) and
-      succ(pred, succ, c) and
-      if c instanceof ConditionalCompletion then super.getCompletion() = c else any()
-    }
-
-    override predicate hasExitScope(CfgInput::CfgScope scope, ControlFlowElement last, Completion c) {
-      this.appliesTo(last) and
-      succExit(scope, last, c) and
-      if c instanceof ConditionalCompletion then super.getCompletion() = c else any()
-    }
-
-    override predicate hasSuccessor(ControlFlowElement pred, ControlFlowElement succ, Completion c) {
-      none()
+    bindingset[parent, parentCompletion]
+    predicate condPropagateExpr(
+      ControlFlowElement parent, ConditionalCompletion parentCompletion, ControlFlowElement child,
+      ConditionalCompletion childCompletion
+    ) {
+      condPropagateAstExpr(parent.asAstNode(), parentCompletion, child.asAstNode(), childCompletion)
     }
   }
 }