Merge pull request #17363 from michaelnebel/modelgen/fieldbasedimprovements

C#/Java: Content based model generation improvements.

shared/dataflow/codeql/dataflow/internal/ContentDataFlowImpl.qll

@@ -271,6 +271,38 @@ module MakeImplContentDataFlow<LocationSig Location, InputSig<Location> Lang> {
           result = head + "." + tail
         )
       }
+
+      private ContentSet getAtIndex(int i) {
+        i = 0 and
+        result = this.getHead()
+        or
+        i > 0 and
+        result = this.getTail().getAtIndex(i - 1)
+      }
+
+      private AccessPath reverse0(int i) {
+        i = -1 and result = TAccessPathNil()
+        or
+        i >= 0 and
+        result = TAccessPathCons(this.getAtIndex(i), this.reverse0(i - 1))
+      }
+
+      /**
+       * Gets the length of this access path.
+       */
+      private int length() {
+        result = 0 and this = TAccessPathNil()
+        or
+        result = 1 + this.getTail().length()
+      }
+
+      /**
+       * Gets the reversed access path, if any.
+       *
+       * Note that not all access paths have a reverse as these are not
+       * included by default in the IPA type.
+       */
+      AccessPath reverse() { result = this.reverse0(this.length() - 1) }
     }
 
     /**

shared/mad/codeql/mad/modelgenerator/ModelPrinting.qll

@@ -64,14 +64,23 @@ module ModelPrintingImpl<ModelPrintingLangSig Lang> {
 
     /**
      * Gets the summary model for `api` with `input`, `output` and `kind`.
+     * The model is lifted in case `lift` is true.
      */
     bindingset[input, output, kind]
-    private string asSummaryModel(Printing::SummaryApi api, string input, string output, string kind) {
-      result =
-        asPartialModel(api.lift()) + input + ";" //
-          + output + ";" //
-          + kind + ";" //
-          + Printing::getProvenance()
+    private string asSummaryModel(
+      Printing::SummaryApi api, string input, string output, string kind, boolean lift
+    ) {
+      exists(Lang::Callable c |
+        lift = true and c = api.lift()
+        or
+        lift = false and c = api
+      |
+        result =
+          asPartialModel(c) + input + ";" //
+            + output + ";" //
+            + kind + ";" //
+            + Printing::getProvenance()
+      )
     }
 
     string asNeutralSummaryModel(Printing::SummaryApi api) {
@@ -82,31 +91,35 @@ module ModelPrintingImpl<ModelPrintingLangSig Lang> {
     }
 
     /**
-     * Gets the value summary model for `api` with `input` and `output`.
+     * Gets the lifted value summary model for `api` with `input` and `output`.
      */
     bindingset[input, output]
-    string asValueModel(Printing::SummaryApi api, string input, string output) {
-      result = asSummaryModel(api, input, output, "value")
+    string asLiftedValueModel(Printing::SummaryApi api, string input, string output) {
+      result = asModel(api, input, output, true, true)
     }
 
     /**
-     * Gets the taint summary model for `api` with `input` and `output`.
+     * Gets the lifted taint summary model for `api` with `input` and `output`.
      */
     bindingset[input, output]
-    string asTaintModel(Printing::SummaryApi api, string input, string output) {
-      result = asSummaryModel(api, input, output, "taint")
+    string asLiftedTaintModel(Printing::SummaryApi api, string input, string output) {
+      result = asModel(api, input, output, false, true)
     }
 
     /**
      * Gets the summary model for `api` with `input` and `output`.
+     * (1) If `preservesValue` is true a "value" model is created.
+     * (2) If `lift` is true the model is lifted to the best possible type.
      */
     bindingset[input, output, preservesValue]
-    string asModel(Printing::SummaryApi api, string input, string output, boolean preservesValue) {
+    string asModel(
+      Printing::SummaryApi api, string input, string output, boolean preservesValue, boolean lift
+    ) {
       preservesValue = true and
-      result = asValueModel(api, input, output)
+      result = asSummaryModel(api, input, output, "value", lift)
       or
       preservesValue = false and
-      result = asTaintModel(api, input, output)
+      result = asSummaryModel(api, input, output, "taint", lift)
     }
 
     /**