Merge pull request #21116 from github/tausbn/python-add-dataflow-overlay-annotations

Add `overlay[local]` annotations

Author: tausbn

python/ql/lib/analysis/DefinitionTracking.qll

@@ -471,11 +471,10 @@ Definition getUniqueDefinition(Expr use) {
   not result = TLocalDefinition(use)
 }
 
-/** A helper class to get suitable locations for attributes */
-class NiceLocationExpr extends Expr {
-  /** Gets a textual representation of this element. */
-  override string toString() { result = this.(Expr).toString() }
+final class FinalExpr = Expr;
 
+/** A helper class to get suitable locations for attributes */
+class NiceLocationExpr extends FinalExpr {
   /**
    * Holds if this element is at the specified location.
    * The location spans column `bc` of line `bl` to

python/ql/lib/change-notes/2026-02-18-add-overlay-annotations.md

@@ -0,0 +1,5 @@
+---
+category: majorAnalysis
+---
+
+- The CodeQL Python libraries have been updated to be compatible with overlay evaluation. This should result in a significant speedup on analyses for which a base database already exists. Note that it may be necessary to add `overlay[local?] module;` to user-managed libraries that extend classes that are now marked as `overlay[local]`.

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

@@ -451,6 +451,7 @@ module API {
    * allowing this predicate to be used in a negative
    * context when constructing new nodes.
    */
+  overlay[local]
   predicate moduleImportExists(string m) {
     Impl::isImported(m) and
     // restrict `moduleImport` so it will never give results for a dotted name. Note
@@ -695,6 +696,7 @@ module API {
      *
      * This is determined syntactically.
      */
+    overlay[local]
     cached
     predicate isImported(string name) {
       // Ignore the following module name for Python 2, as we alias `__builtin__` to `builtins` elsewhere

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

@@ -1,3 +1,6 @@
+overlay[local]
+module;
+
 import python
 private import semmle.python.internal.CachedStages
 

python/ql/lib/semmle/python/AstGenerated.qll

@@ -3,6 +3,8 @@
  *      WARNING: Any modifications to this file will be lost.
  *      Relations can be changed by modifying master.py.
  */
+overlay[local]
+module;
 
 import python
 

python/ql/lib/semmle/python/Class.qll

@@ -1,6 +1,8 @@
 /**
  * Provides classes representing Python classes.
  */
+overlay[local]
+module;
 
 import python
 

python/ql/lib/semmle/python/Comment.qll

@@ -1,6 +1,8 @@
 /**
  * Provides classes representing comments in Python.
  */
+overlay[local]
+module;
 
 import python
 

python/ql/lib/semmle/python/Comprehensions.qll

@@ -1,3 +1,6 @@
+overlay[local]
+module;
+
 import python
 
 /** The base class for list, set and dictionary comprehensions, and generator expressions. */

python/ql/lib/semmle/python/Constants.qll

@@ -1,4 +1,6 @@
 /** Standard builtin types and modules */
+overlay[local]
+module;
 
 import python
 

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

@@ -1,3 +1,6 @@
+overlay[local]
+module;
+
 private import python
 private import semmle.python.internal.CachedStages