cached stages iteration 2

python/ql/lib/semmle/python/ApiGraphs.qll

@@ -9,6 +9,7 @@
 // Importing python under the `py` namespace to avoid importing `CallNode` from `Flow.qll` and thereby having a naming conflict with `API::CallNode`.
 private import python as py
 import semmle.python.dataflow.new.DataFlow
+private import semmle.python.internal.CachedStages
 
 /**
  * Provides classes and predicates for working with APIs used in a database.
@@ -683,6 +684,7 @@ module API {
      */
     cached
     DataFlow::LocalSourceNode trackUseNode(DataFlow::LocalSourceNode src) {
+      Stages::TypeTracking::ref() and
       result = trackUseNode(src, DataFlow::TypeTracker::end()) and
       not result instanceof DataFlow::ModuleVariableNode
     }

python/ql/lib/semmle/python/AstExtended.qll

@@ -1,4 +1,5 @@
 import python
+private import semmle.python.internal.CachedStages
 
 /** A syntactic node (Class, Function, Module, Expr, Stmt or Comprehension) corresponding to a flow node */
 abstract class AstNode extends AstNode_ {
@@ -20,6 +21,7 @@ abstract class AstNode extends AstNode_ {
   ControlFlowNode getAFlowNode() { py_flow_bb_node(result, this, _, _) }
 
   /** Gets the location for this AST node */
+  cached
   Location getLocation() { none() }
 
   /**
@@ -106,7 +108,10 @@ class Comprehension extends Comprehension_, AstNode {
 
   override string toString() { result = "Comprehension" }
 
-  override Location getLocation() { result = Comprehension_.super.getLocation() }
+  override Location getLocation() {
+    Stages::SSA::ref() and
+    result = Comprehension_.super.getLocation()
+  }
 
   override AstNode getAChildNode() { result = this.getASubExpression() }
 

python/ql/lib/semmle/python/Exprs.qll

@@ -1,6 +1,7 @@
 import python
 private import semmle.python.pointsto.PointsTo
 private import semmle.python.objects.ObjectInternal
+private import semmle.python.internal.CachedStages
 
 /** An expression */
 class Expr extends Expr_, AstNode {
@@ -8,7 +9,11 @@ class Expr extends Expr_, AstNode {
   override Scope getScope() { py_scopes(this, result) }
 
   /** Gets a textual representation of this element. */
-  override string toString() { result = "Expression" }
+  cached
+  override string toString() {
+    Stages::SSA::ref() and
+    result = "Expression"
+  }
 
   /** Gets the module in which this expression occurs */
   Module getEnclosingModule() { result = this.getScope().getEnclosingModule() }

python/ql/lib/semmle/python/Flow.qll

@@ -1001,12 +1001,16 @@ class BasicBlock extends @py_flow_node {
   string toString() { result = "BasicBlock" }
 
   /** Whether this basic block strictly dominates the other */
-  pragma[nomagic]
+  cached
-  predicate strictlyDominates(BasicBlock other) { other.getImmediateDominator+() = this }
+  predicate strictlyDominates(BasicBlock other) {
+    Stages::SSA::ref() and
+    other.getImmediateDominator+() = this
+  }
 
   /** Whether this basic block dominates the other */
-  pragma[nomagic]
+  cached
   predicate dominates(BasicBlock other) {
+    Stages::SSA::ref() and
     this = other
     or
     this.strictlyDominates(other)

python/ql/lib/semmle/python/Module.qll

@@ -1,6 +1,7 @@
 import python
 private import semmle.python.objects.ObjectAPI
 private import semmle.python.objects.Modules
+private import semmle.python.internal.CachedStages
 
 /**
  * A module. This is the top level element in an AST, corresponding to a source file.
@@ -221,7 +222,9 @@ private predicate transitively_imported_from_entry_point(File file) {
   )
 }
 
+cached
 string moduleNameFromFile(Container file) {
+  Stages::SSA::ref() and
   exists(string basename |
     basename = moduleNameFromBase(file) and
     legalShortName(basename)

python/ql/lib/semmle/python/dataflow/new/internal/TypeTracker.qll

@@ -1,6 +1,7 @@
 /** Step Summaries and Type Tracking */
 
 private import TypeTrackerSpecific
+private import semmle.python.internal.CachedStages
 
 /**
  * A string that may appear as the name of a piece of content. This will usually include things like:
@@ -40,6 +41,7 @@ private module Cached {
   /** Gets the summary resulting from appending `step` to type-tracking summary `tt`. */
   cached
   TypeTracker append(TypeTracker tt, StepSummary step) {
+    Stages::TypeTracking::ref() and
     exists(Boolean hasCall, OptionalContentName content | tt = MkTypeTracker(hasCall, content) |
       step = LevelStep() and result = tt
       or

python/ql/lib/semmle/python/internal/CachedStages.qll

@@ -37,6 +37,7 @@ module Stages {
    */
   cached
   module SSA {
+    // TODO: This is more a "basic AST", not a "SSA" stage.
     /**
      * Always holds.
      * Ensures that a predicate is evaluated as part of the Ast stage.
@@ -47,6 +48,10 @@ module Stages {
     private import semmle.python.essa.SsaDefinitions as SsaDefinitions
     private import semmle.python.essa.SsaCompute as SsaCompute
     private import semmle.python.essa.Essa as Essa
+    private import semmle.python.Module as PyModule
+    private import semmle.python.Exprs as Exprs
+    private import semmle.python.AstExtended as AstExtended
+    private import semmle.python.Flow as PyFlow
 
     /**
      * DONT USE!
@@ -61,6 +66,47 @@ module Stages {
       SsaCompute::SsaDefinitions::reachesEndOfBlock(_, _, _, _)
       or
       exists(any(Essa::PhiFunction p).getInput(_))
+      or
+      exists(PyModule::moduleNameFromFile(_))
+      or
+      exists(any(Exprs::Expr e).toString())
+      or
+      exists(any(AstExtended::AstNode n).getLocation())
+      or
+      exists(any(PyFlow::BasicBlock b).getImmediateDominator())
+      or
+      any(PyFlow::BasicBlock b).strictlyDominates(_)
+      or
+      any(PyFlow::BasicBlock b).dominates(_)
+    }
+  }
+
+  /**
+   * The `TypeTracking` stage.
+   */
+  cached
+  module TypeTracking {
+    /**
+     * Always holds.
+     * Ensures that a predicate is evaluated as part of the Ast stage.
+     */
+    cached
+    predicate ref() { 1 = 1 }
+
+    private import semmle.python.dataflow.new.DataFlow::DataFlow as NewDataFlow
+    private import semmle.python.ApiGraphs::API as API
+
+    /**
+     * DONT USE!
+     * Contains references to each predicate that use the above `ref` predicate.
+     */
+    cached
+    predicate backref() {
+      1 = 1
+      or
+      exists(any(NewDataFlow::TypeTracker t).append(_))
+      or
+      exists(any(API::Node n).getAMember().getAUse())
     }
   }
 
@@ -83,6 +129,7 @@ module Stages {
     private import semmle.python.types.Object as TypeObject
     private import semmle.python.objects.TObject as TObject
     private import semmle.python.Flow as Flow
+    private import semmle.python.objects.ObjectInternal as ObjectInternal
 
     /**
      * DONT USE!
@@ -107,6 +154,8 @@ module Stages {
       exists(TObject::TObject f)
       or
       exists(any(Flow::ControlFlowNode c).toString())
+      or
+      exists(any(ObjectInternal::ObjectInternal o).toString())
     }
   }
 

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

@@ -15,9 +15,11 @@ import semmle.python.objects.Callables
 import semmle.python.objects.Constants
 import semmle.python.objects.Sequences
 import semmle.python.objects.Descriptors
+private import semmle.python.internal.CachedStages
 
 class ObjectInternal extends TObject {
   /** Gets a textual representation of this element. */
+  cached
   abstract string toString();
 
   /**
@@ -213,7 +215,10 @@ class ObjectInternal extends TObject {
 class BuiltinOpaqueObjectInternal extends ObjectInternal, TBuiltinOpaqueObject {
   override Builtin getBuiltin() { this = TBuiltinOpaqueObject(result) }
 
-  override string toString() { result = this.getBuiltin().getClass().getName() + " object" }
+  override string toString() {
+    Stages::DataFlow::ref() and
+    result = this.getBuiltin().getClass().getName() + " object"
+  }
 
   override boolean booleanValue() {
     // TO DO ... Depends on class. `result = this.getClass().instancesBooleanValue()`