C++: move resolveCall to its own file for perf

This avoids a performance issue in DataFlowImpl::localFlowStep when the
DataFlow::Configuration subclasses in DefaultTaintTracking are active
in the same query as other Configuration
subclasses.
ResolveCall.qll is kept internal for the moment.

Author: rdmarsh2

cpp/ql/lib/semmle/code/cpp/ir/dataflow/DefaultTaintTracking.qll

@@ -4,7 +4,7 @@ private import semmle.code.cpp.ir.dataflow.DataFlow
 private import semmle.code.cpp.ir.dataflow.internal.DataFlowUtil
 private import semmle.code.cpp.ir.dataflow.DataFlow3
 private import semmle.code.cpp.ir.IR
-private import semmle.code.cpp.ir.dataflow.internal.DataFlowDispatch as Dispatch
+private import semmle.code.cpp.ir.dataflow.internal.ResolveCall
 private import semmle.code.cpp.controlflow.IRGuards
 private import semmle.code.cpp.models.interfaces.Taint
 private import semmle.code.cpp.models.interfaces.DataFlow
@@ -355,20 +355,6 @@ predicate taintedIncludingGlobalVars(Expr source, Element tainted, string global
  */
 GlobalOrNamespaceVariable globalVarFromId(string id) { id = result.getQualifiedName() }
 
-/**
- * Resolve potential target function(s) for `call`.
- *
- * If `call` is a call through a function pointer (`ExprCall`) or
- * targets a virtual method, simple data flow analysis is performed
- * in order to identify target(s).
- */
-Function resolveCall(Call call) {
-  exists(CallInstruction callInstruction |
-    callInstruction.getAST() = call and
-    result = Dispatch::viableCallable(callInstruction)
-  )
-}
-
 /**
  * Provides definitions for augmenting source/sink pairs with data-flow paths
  * between them. From a `@kind path-problem` query, import this module in the

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

@@ -0,0 +1,23 @@
+/**
+ * Provides a predicate for non-contextual virtual dispatch and function
+ * pointer resolution, built on top of the `DataFlowDispatch` library.
+ */
+
+import cpp
+private import semmle.code.cpp.ir.ValueNumbering
+private import DataFlowDispatch
+private import semmle.code.cpp.ir.IR
+
+/**
+ * Resolve potential target function(s) for `call`.
+ *
+ * If `call` is a call through a function pointer (`ExprCall`) or
+ * targets a virtual method, simple data flow analysis is performed
+ * in order to identify target(s).
+ */
+Function resolveCall(Call call) {
+  exists(CallInstruction callInstruction |
+    callInstruction.getAST() = call and
+    result = viableCallable(callInstruction)
+  )
+}

cpp/ql/lib/semmle/code/cpp/security/FunctionWithWrappers.qll

@@ -17,7 +17,7 @@
 
 import cpp
 import PrintfLike
-private import TaintTracking
+private import semmle.code.cpp.ir.dataflow.internal.ResolveCall
 
 bindingset[index]
 private string toCause(Function func, int index) {