Expose whether a PointerVal has nullability properties.

Also remove unused parameter of getPointerNullState.

PiperOrigin-RevId: 533139747

nullability/pointer_nullability.cc

@@ -34,8 +34,13 @@ PointerValue* getPointerValueFromExpr(const Expr* PointerExpr,
       Env.getValue(*PointerExpr, SkipPast::Reference));
 }
 
+bool hasPointerNullState(const dataflow::PointerValue& PointerVal) {
+  return PointerVal.getProperty(kKnown) != nullptr &&
+         PointerVal.getProperty(kNull) != nullptr;
+}
+
 std::pair<AtomicBoolValue&, AtomicBoolValue&> getPointerNullState(
-    const PointerValue& PointerVal, const Environment& Env) {
+    const PointerValue& PointerVal) {
   auto& PointerKnown = *cast<AtomicBoolValue>(PointerVal.getProperty(kKnown));
   auto& PointerNull = *cast<AtomicBoolValue>(PointerVal.getProperty(kNull));
   return {PointerKnown, PointerNull};
@@ -61,7 +66,7 @@ void initPointerNullState(PointerValue& PointerVal, Environment& Env,
 }
 
 bool isNullable(const PointerValue& PointerVal, const Environment& Env) {
-  auto [PointerKnown, PointerNull] = getPointerNullState(PointerVal, Env);
+  auto [PointerKnown, PointerNull] = getPointerNullState(PointerVal);
   auto& PointerNotKnownNull =
       Env.makeNot(Env.makeAnd(PointerKnown, PointerNull));
   return !Env.flowConditionImplies(PointerNotKnownNull);

nullability/pointer_nullability.h

@@ -29,13 +29,22 @@ namespace nullability {
 dataflow::PointerValue* getPointerValueFromExpr(
     const Expr* PointerExpr, const dataflow::Environment& Env);
 
+// Returns true if the pointer has all properties necessary for representing
+// complete nullness information.
+// Otherwise, returns false.
+//
+// Pointers that are the value of some expression always have null state once
+// that expression has been analyzed. Other pointers, like the values of unused
+// parameters, may lack this state. This state is only set by
+// PointerNullabilityAnalysis, not by the dataflow framework.
+bool hasPointerNullState(const dataflow::PointerValue& PointerVal);
+
 /// Returns the properties representing the nullness information of a pointer.
 ///
 /// The first boolean indicates if the pointer's nullability is known.
 /// The second boolean indicates if the pointer's value is null.
 std::pair<dataflow::AtomicBoolValue&, dataflow::AtomicBoolValue&>
-getPointerNullState(const dataflow::PointerValue& PointerVal,
-                    const dataflow::Environment& Env);
+getPointerNullState(const dataflow::PointerValue& PointerVal);
 
 /// Sets the nullness properties on `PointerVal` if not already initialised.
 ///

nullability/pointer_nullability_analysis.cc

@@ -298,8 +298,8 @@ void transferFlowSensitiveNullCheckComparison(
 
   if (!LHS || !RHS) return;
 
-  auto [LHSKnown, LHSNull] = getPointerNullState(*LHS, State.Env);
-  auto [RHSKnown, RHSNull] = getPointerNullState(*RHS, State.Env);
+  auto [LHSKnown, LHSNull] = getPointerNullState(*LHS);
+  auto [RHSKnown, RHSNull] = getPointerNullState(*RHS);
   auto& LHSKnownNotNull =
       State.Env.makeAnd(LHSKnown, State.Env.makeNot(LHSNull));
   auto& RHSKnownNotNull =
@@ -325,8 +325,7 @@ void transferFlowSensitiveNullCheckImplicitCastPtrToBool(
       getPointerValueFromExpr(CastExpr->IgnoreImplicit(), State.Env);
   if (!PointerVal) return;
 
-  auto [PointerKnown, PointerNull] =
-      getPointerNullState(*PointerVal, State.Env);
+  auto [PointerKnown, PointerNull] = getPointerNullState(*PointerVal);
   auto& CastExprLoc = State.Env.createStorageLocation(*CastExpr);
   State.Env.setValue(CastExprLoc, State.Env.makeNot(PointerNull));
   State.Env.setStorageLocation(*CastExpr, CastExprLoc);
@@ -726,8 +725,8 @@ bool PointerNullabilityAnalysis::merge(QualType Type, const Value& Val1,
     return false;
   }
 
-  auto [Known1, Null1] = getPointerNullState(cast<PointerValue>(Val1), Env1);
-  auto [Known2, Null2] = getPointerNullState(cast<PointerValue>(Val2), Env2);
+  auto [Known1, Null1] = getPointerNullState(cast<PointerValue>(Val1));
+  auto [Known2, Null2] = getPointerNullState(cast<PointerValue>(Val2));
 
   auto& Known = mergeBoolValues(Known1, Env1, Known2, Env2, MergedEnv);
   auto& Null = mergeBoolValues(Null1, Env1, Null2, Env2, MergedEnv);