QL4QL: Extend ql/inline-overlay-caller

Author: kaspersv

ql/ql/src/codeql_ql/ast/Ast.qll

@@ -2542,6 +2542,10 @@ private class CallerArg extends AnnotationArg {
   CallerArg() { this.getValue() = "caller" }
 }
 
+private class CallerQArg extends AnnotationArg {
+  CallerQArg() { this.getValue() = "caller?" }
+}
+
 private class LocalArg extends AnnotationArg {
   LocalArg() { this.getValue() = "local" }
 }
@@ -2616,6 +2620,13 @@ class OverlayCaller extends Annotation {
   override string toString() { result = "overlay[caller]" }
 }
 
+/** An `overlay[caller?]` annotation. */
+class OverlayCallerQ extends Annotation {
+  OverlayCallerQ() { this.getName() = "overlay" and this.getArgs(0) instanceof CallerQArg }
+
+  override string toString() { result = "overlay[caller?]" }
+}
+
 /** An `overlay[local]` annotation. */
 class OverlayLocal extends Annotation {
   OverlayLocal() { this.getName() = "overlay" and this.getArgs(0) instanceof LocalArg }

ql/ql/src/queries/overlay/InlineOverlayCaller.ql

@@ -31,11 +31,12 @@ where
   mayBeLocal(p) and
   p.getAnAnnotation() instanceof Inline and
   not p.getAnAnnotation() instanceof OverlayCaller and
+  not p.getAnAnnotation() instanceof OverlayCallerQ and
   not p.isPrivate()
 select p,
   "This possibly local non-private inline predicate will not " +
     "be inlined across the overlay frontier. This may negatively " +
     "affect evaluation performance. Consider adding an " +
-    "`overlay[caller]` annotation to allow inlining across the " +
-    "overlay frontier. Note that adding an `overlay[caller]` " +
+    "`overlay[caller]` or `overlay[caller?]` annotation to allow inlining across the " +
+    "overlay frontier. Note that adding an `overlay[caller]` or `overlay[caller?]`" +
     "annotation affects semantics under overlay evaluation."

ql/ql/test/queries/overlay/InlineOverlayCaller/Test.qll

@@ -12,3 +12,7 @@ predicate bar(int x) { x = 43 }
 
 pragma[inline]
 private predicate baz(int x) { x = 44 }
+
+overlay[caller?]
+pragma[inline]
+predicate baw(int x) { x == 45 }