PS: Implement conditional splitting in the Powershell CFG.

Author: MathiasVP

powershell/ql/lib/semmle/code/powershell/controlflow/internal/ControlFlowGraphImpl.qll

@@ -12,7 +12,6 @@ private import Completion
 private module CfgInput implements CfgShared::InputSig<Location> {
   private import ControlFlowGraphImpl as Impl
   private import Completion as Comp
-  private import Splitting as Splitting
   private import semmle.code.powershell.Cfg as Cfg
 
   class Completion = Comp::Completion;
@@ -35,10 +34,6 @@ private module CfgInput implements CfgShared::InputSig<Location> {
     scope.(Impl::CfgScope).exit(last, c)
   }
 
-  class SplitKindBase = Splitting::TSplitKind;
-
-  class Split = Splitting::Split;
-
   class SuccessorType = Cfg::SuccessorType;
 
   SuccessorType getAMatchingSuccessorType(Completion c) { result = c.getAMatchingSuccessorType() }
@@ -58,7 +53,22 @@ private module CfgInput implements CfgShared::InputSig<Location> {
 }
 
 private import CfgInput
-import CfgShared::Make<Location, CfgInput>
+
+private module CfgSplittingInput implements CfgShared::SplittingInputSig<Location, CfgInput> {
+  private import Splitting as S
+
+  class SplitKindBase = S::TSplitKind;
+
+  class Split = S::Split;
+}
+
+private module ConditionalCompletionSplittingInput implements
+  CfgShared::ConditionalCompletionSplittingInputSig<Location, CfgInput, CfgSplittingInput>
+{
+  import Splitting::ConditionalCompletionSplitting::ConditionalCompletionSplittingInput
+}
+
+import CfgShared::MakeWithSplitting<Location, CfgInput, CfgSplittingInput, ConditionalCompletionSplittingInput>
 
 class CfgScope extends Scope {
   predicate entry(Ast first) { first(this, first) }

powershell/ql/lib/semmle/code/powershell/controlflow/internal/Splitting.qll

@@ -3,20 +3,19 @@
  */
 
 private import powershell
-private import Completion
+private import Completion as Comp
+private import Comp
 private import ControlFlowGraphImpl
 private import Cfg::SuccessorTypes
 private import semmle.code.powershell.controlflow.ControlFlowGraph as Cfg
 
 cached
 private module Cached {
   cached
-  newtype TSplitKind =
-    TConditionalCompletionSplitKind()
+  newtype TSplitKind = TConditionalCompletionSplitKind()
 
   cached
-  newtype TSplit =
-    TConditionalCompletionSplit(ConditionalCompletion c)
+  newtype TSplit = TConditionalCompletionSplit(ConditionalCompletion c)
 }
 
 import Cached
@@ -27,59 +26,57 @@ class Split extends TSplit {
   string toString() { none() }
 }
 
-private module ConditionalCompletionSplitting {
-  /**
-   * A split for conditional completions.
-   */
+module ConditionalCompletionSplitting {
   class ConditionalCompletionSplit extends Split, TConditionalCompletionSplit {
     ConditionalCompletion completion;
 
     ConditionalCompletionSplit() { this = TConditionalCompletionSplit(completion) }
 
+    ConditionalCompletion getCompletion() { result = completion }
+
     override string toString() { result = completion.toString() }
   }
 
-  // private class ConditionalCompletionSplitKind extends SplitKind, TConditionalCompletionSplitKind {
-  //   override int getListOrder() { result = 0 }
-
-  //   override predicate isEnabled(Ast n) { this.appliesTo(n) }
-
-  //   override string toString() { result = "ConditionalCompletion" }
-  // }
-
-  int getNextListOrder() { result = 1 }
-
-//   private class ConditionalCompletionSplitImpl extends SplitImpl instanceof ConditionalCompletionSplit
-//   {
-//     ConditionalCompletion completion;
-
-//     ConditionalCompletionSplitImpl() { this = TConditionalCompletionSplit(completion) }
+  private class ConditionalCompletionSplitKind_ extends SplitKind, TConditionalCompletionSplitKind {
+    override int getListOrder() { result = 0 }
 
-//     override ConditionalCompletionSplitKind getKind() { any() }
+    override predicate isEnabled(Ast n) { this.appliesTo(n) }
 
-//     override predicate hasEntry(Ast pred, Ast succ, Completion c) {
-//       succ(pred, succ, c) and
-//       last(succ, _, completion) and
-//       none() // TODO
-//     }
-
-//     override predicate hasEntryScope(Cfg::CfgScope scope, Ast succ) { none() }
-
-//     override predicate hasExit(Ast pred, Ast succ, Completion c) {
-//       this.appliesTo(pred) and
-//       succ(pred, succ, c) and
-//       if c instanceof ConditionalCompletion then completion = c else any()
-//     }
-
-//     override predicate hasExitScope(Cfg::CfgScope scope, Ast last, Completion c) {
-//       this.appliesTo(last) and
-//       succExit(scope, last, c) and
-//       if c instanceof ConditionalCompletion then completion = c else any()
-//     }
+    override string toString() { result = "ConditionalCompletion" }
+  }
 
-//     override predicate hasSuccessor(Ast pred, Ast succ, Completion c) { none() }
-//   }
+  module ConditionalCompletionSplittingInput {
+    private import Completion as Comp
+
+    class ConditionalCompletion = Comp::ConditionalCompletion;
+
+    class ConditionalCompletionSplitKind extends ConditionalCompletionSplitKind_, TSplitKind { }
+
+    class ConditionalCompletionSplit = ConditionalCompletionSplitting::ConditionalCompletionSplit;
+
+    bindingset[parent, parentCompletion]
+    predicate condPropagateExpr(
+      Ast parent, ConditionalCompletion parentCompletion, Ast child,
+      ConditionalCompletion childCompletion
+    ) {
+      child = parent.(NotExpr).getOperand() and
+      childCompletion.(BooleanCompletion).getDual() = parentCompletion
+      or
+      childCompletion = parentCompletion and
+      (
+        child = parent.(LogicalAndExpr).getAnOperand()
+        or
+        child = parent.(LogicalOrExpr).getAnOperand()
+        or
+        child = parent.(ConditionalExpr).getBranch(_)
+      )
+    }
+
+    int getNextListOrder() { result = 1 }
+
+    private class ConditionalCompletionSplitImpl extends SplitImplementations::ConditionalCompletionSplitting::ConditionalCompletionSplitImpl
+    { }
+  }
 }
 
 class ConditionalCompletionSplit = ConditionalCompletionSplitting::ConditionalCompletionSplit;
-