Python points-to: restore getArgumentForCall() API method.

python/ql/src/semmle/python/objects/Callables.qll

@@ -53,6 +53,7 @@ abstract class CallableObjectInternal extends ObjectInternal {
     override int length() { none() }
 
     abstract predicate neverReturns();
+
 }
 
 
@@ -151,6 +152,11 @@ class PythonFunctionObjectInternal extends CallableObjectInternal, TPythonFuncti
     override predicate neverReturns() {
         InterProceduralPointsTo::neverReturns(this.getScope())
     }
+
+    override predicate functionAndOffset(CallableObjectInternal function, int offset) {
+        function = this and offset = 0
+    }
+
 }
 
 
@@ -262,6 +268,10 @@ class BuiltinFunctionObjectInternal extends CallableObjectInternal, TBuiltinFunc
         this = Module::named("sys").attr("exit")
     }
 
+    override predicate functionAndOffset(CallableObjectInternal function, int offset) {
+        function = this and offset = 0
+    }
+
 }
 
 
@@ -347,6 +357,10 @@ class BuiltinMethodObjectInternal extends CallableObjectInternal, TBuiltinMethod
 
     override predicate neverReturns() { none() }
 
+    override predicate functionAndOffset(CallableObjectInternal function, int offset) {
+        function = this and offset = 0
+    }
+
 }
 
 class BoundMethodObjectInternal extends CallableObjectInternal, TBoundMethod {
@@ -422,6 +436,10 @@ class BoundMethodObjectInternal extends CallableObjectInternal, TBoundMethod {
         this.getFunction().neverReturns()
    }
 
+    override predicate functionAndOffset(CallableObjectInternal function, int offset) {
+        function = this.getFunction() and offset = 1
+    }
+
 }
 
 

python/ql/src/semmle/python/objects/Classes.qll

@@ -122,6 +122,10 @@ class PythonClassObjectInternal extends ClassObjectInternal, TPythonClassObject
 
     override boolean isComparable() { result = true }
 
+    override predicate functionAndOffset(CallableObjectInternal function, int offset) {
+        this.lookup("__init__", function, _) and offset = 1
+    }
+
 }
 
 class BuiltinClassObjectInternal extends ClassObjectInternal, TBuiltinClassObject {

python/ql/src/semmle/python/objects/ObjectAPI.qll

@@ -118,17 +118,35 @@ class CallableValue extends Value {
         result = this.(CallableObjectInternal).getParameterByName(name)
     }
 
-    ControlFlowNode getArgumentForCall(CallNode call, NameNode param) {
-        this.getACall() = call and
-        (
-            exists(int n | call.getArg(n) = result and param = this.getParameter(n))
+    ControlFlowNode getArgumentForCall(CallNode call, int n) {
+        exists(ObjectInternal called, int offset |
+            PointsToInternal::pointsTo(call.getFunction(), _, called, _) and
+            called.functionAndOffset(this, offset) 
+            |
+            call.getArg(n-offset) = result
             or
-            exists(string name | call.getArgByName(name) = result and param = this.getParameterByName(name))
+            exists(string name | call.getArgByName(name) = result and this.(PythonFunctionObjectInternal).getScope().getArg(n+offset).getName() = name)
+            or
+            called instanceof BoundMethodObjectInternal and
+            offset = 1 and n = 0 and result = call.getFunction().(AttrNode).getObject()
         )
-        or
-        exists(BoundMethodObjectInternal bm |
-            result = getArgumentForCall(call, param) and
-            this = bm.getFunction()
+    }
+
+    ControlFlowNode getNamedArgumentForCall(CallNode call, string name) {
+        exists(CallableObjectInternal called, int offset |
+            PointsToInternal::pointsTo(call.getFunction(), _, called, _) and
+            called.functionAndOffset(this, offset)
+            |
+            exists(int n |
+                call.getArg(n) = result and
+                this.(PythonFunctionObjectInternal).getScope().getArg(n+offset).getName() = name
+            )
+            or
+            call.getArgByName(name) = result and
+            exists(this.(PythonFunctionObjectInternal).getScope().getArgByName(name))
+            or
+            called instanceof BoundMethodObjectInternal and
+            offset = 1 and name = "self" and result = call.getFunction().(AttrNode).getObject()
         )
     }
 

python/ql/src/semmle/python/objects/ObjectInternal.qll

@@ -103,6 +103,8 @@ class ObjectInternal extends TObject {
      */
     abstract int length();
 
+    predicate functionAndOffset(CallableObjectInternal function, int offset) { none() }
+
 }
 
 

python/ql/src/semmle/python/types/FunctionObject.qll

@@ -71,14 +71,14 @@ abstract class FunctionObject extends Object {
         This predicate will correctly handle `x.y()`, treating `x` as the zeroth argument.
     */
     ControlFlowNode getArgumentForCall(CallNode call, int n) {
-        result = theCallable().getArgumentForCall(call, this.getFunction().getArg(n).asName().getAFlowNode())
+        result = theCallable().getArgumentForCall(call, n)
     }
 
     /** Gets the `ControlFlowNode` that will be passed as the named argument to `this` when called at `call`.
         This predicate will correctly handle `x.y()`, treating `x` as the self argument.
     */
     ControlFlowNode getNamedArgumentForCall(CallNode call, string name) {
-        result = theCallable().getArgumentForCall(call, this.getFunction().getArgByName(name).asName().getAFlowNode())
+        result = theCallable().getNamedArgumentForCall(call, name)
     }
 
     /** Whether this function never returns. This is an approximation.