Dataflow: Add totalorder predicates to all languages.

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

@@ -9,7 +9,7 @@ private import DataFlowUtil
 /**
  * Gets a function that might be called by `call`.
  */
-Function viableCallable(DataFlowCall call) {
+DataFlowCallable viableCallable(DataFlowCall call) {
   result = call.(Call).getTarget()
   or
   // If the target of the call does not have a body in the snapshot, it might

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

@@ -242,7 +242,17 @@ class CastNode extends Node {
   CastNode() { none() } // stub implementation
 }
 
-class DataFlowCallable = Function;
+class DataFlowCallable extends Function {
+  /** Gets a best-effort total ordering. */
+  int totalorder() {
+    this =
+      rank[result](DataFlowCallable c, string file, int startline, int startcolumn |
+        c.getLocation().hasLocationInfo(file, startline, startcolumn, _, _)
+      |
+        c order by file, startline, startcolumn
+      )
+  }
+}
 
 class DataFlowExpr = Expr;
 
@@ -261,7 +271,17 @@ class DataFlowCall extends Expr instanceof Call {
   ExprNode getNode() { result.getExpr() = this }
 
   /** Gets the enclosing callable of this call. */
-  Function getEnclosingCallable() { result = this.getEnclosingFunction() }
+  DataFlowCallable getEnclosingCallable() { result = this.getEnclosingFunction() }
+
+  /** Gets a best-effort total ordering. */
+  int totalorder() {
+    this =
+      rank[result](DataFlowCall c, int startline, int startcolumn |
+        c.getLocation().hasLocationInfo(_, startline, startcolumn, _, _)
+      |
+        c order by startline, startcolumn
+      )
+  }
 }
 
 class NodeRegion instanceof Unit {

cpp/ql/lib/semmle/code/cpp/ir/dataflow/internal/DataFlowPrivate.qll

@@ -1062,6 +1062,16 @@ class DataFlowCallable extends TDataFlowCallable {
     result = this.asSummarizedCallable() or // SummarizedCallable = Function (in CPP)
     result = this.asSourceCallable()
   }
+
+  /** Gets a best-effort total ordering. */
+  int totalorder() {
+    this =
+      rank[result](DataFlowCallable c, string file, int startline, int startcolumn |
+        c.getLocation().hasLocationInfo(file, startline, startcolumn, _, _)
+      |
+        c order by file, startline, startcolumn
+      )
+  }
 }
 
 /**
@@ -1159,6 +1169,16 @@ class DataFlowCall extends TDataFlowCall {
    * Gets the location of this call.
    */
   Location getLocation() { none() }
+
+  /** Gets a best-effort total ordering. */
+  int totalorder() {
+    this =
+      rank[result](DataFlowCall c, int startline, int startcolumn |
+        c.getLocation().hasLocationInfo(_, startline, startcolumn, _, _)
+      |
+        c order by startline, startcolumn
+      )
+  }
 }
 
 /**