[JVMCI] Make ResolvedJavaType return a List<? extends JavaType> [GR-70208]

Author: zapster

substratevm/src/com.oracle.graal.pointsto/src/com/oracle/graal/pointsto/meta/AnalysisType.java

@@ -225,8 +225,14 @@ public abstract class AnalysisType extends AnalysisElement implements WrappedJav
 
     private volatile AnalysisType arrayClass = null;
 
-    private static final List<JavaType> PERMITTED_SUBCLASSES_INIT = new ArrayList<>();
-    private volatile List<JavaType> permittedSubclasses = PERMITTED_SUBCLASSES_INIT;
+    /**
+     * Sentinel marker for the uninitialized state of {@link #permittedSubclasses}. Indicates that
+     * the permitted subclasses (for sealed types) has not yet been computed. Distinguishes this
+     * state from both a computed {@code null} (not sealed) and a computed list (which may be
+     * empty).
+     */
+    private static final List<AnalysisType> PERMITTED_SUBCLASSES_UNINITIALIZED = new ArrayList<>();
+    private volatile List<AnalysisType> permittedSubclasses = PERMITTED_SUBCLASSES_UNINITIALIZED;
 
     @SuppressWarnings("this-escape")
     public AnalysisType(AnalysisUniverse universe, ResolvedJavaType javaType, JavaKind storageKind, AnalysisType objectType, AnalysisType cloneableType) {
@@ -967,9 +973,9 @@ public final AnalysisType getArrayClass() {
     }
 
     @Override
-    public List<JavaType> getPermittedSubclasses() {
-        if (permittedSubclasses == PERMITTED_SUBCLASSES_INIT) {
-            List<JavaType> wrappedPermittedSubclasses = wrapped.getPermittedSubclasses();
+    public List<? extends AnalysisType> getPermittedSubclasses() {
+        if (permittedSubclasses == PERMITTED_SUBCLASSES_UNINITIALIZED) {
+            List<? extends JavaType> wrappedPermittedSubclasses = wrapped.getPermittedSubclasses();
             permittedSubclasses = wrappedPermittedSubclasses == null ? null : wrappedPermittedSubclasses.stream().map(universe::lookup).collect(Collectors.toUnmodifiableList());
         }
         return permittedSubclasses;

substratevm/src/com.oracle.svm.graal/src/com/oracle/svm/graal/meta/SubstrateType.java

@@ -45,7 +45,6 @@
 import jdk.vm.ci.meta.Assumptions.AssumptionResult;
 import jdk.vm.ci.meta.JavaConstant;
 import jdk.vm.ci.meta.JavaKind;
-import jdk.vm.ci.meta.JavaType;
 import jdk.vm.ci.meta.MetaUtil;
 import jdk.vm.ci.meta.ResolvedJavaField;
 import jdk.vm.ci.meta.ResolvedJavaMethod;
@@ -320,7 +319,7 @@ public ResolvedJavaType getArrayClass() {
     }
 
     @Override
-    public List<JavaType> getPermittedSubclasses() {
+    public List<? extends SubstrateType> getPermittedSubclasses() {
         Class<?>[] hubPermittedSubclasses = hub.getPermittedSubclasses();
         if (hubPermittedSubclasses == null) {
             return null;

substratevm/src/com.oracle.svm.hosted/src/com/oracle/svm/hosted/annotation/CustomSubstitutionType.java

@@ -207,7 +207,7 @@ public ResolvedJavaType getArrayClass() {
     }
 
     @Override
-    public List<JavaType> getPermittedSubclasses() {
+    public List<? extends JavaType> getPermittedSubclasses() {
         return original.getPermittedSubclasses();
     }
 

substratevm/src/com.oracle.svm.hosted/src/com/oracle/svm/hosted/meta/HostedArrayClass.java

@@ -29,7 +29,6 @@
 import com.oracle.graal.pointsto.meta.AnalysisType;
 
 import jdk.vm.ci.meta.JavaKind;
-import jdk.vm.ci.meta.JavaType;
 
 public class HostedArrayClass extends HostedClass {
 
@@ -73,7 +72,7 @@ public final HostedType getComponentType() {
     }
 
     @Override
-    public List<JavaType> getPermittedSubclasses() {
+    public List<? extends HostedType> getPermittedSubclasses() {
         return null;
     }
 

substratevm/src/com.oracle.svm.hosted/src/com/oracle/svm/hosted/meta/HostedPrimitiveType.java

@@ -29,7 +29,6 @@
 import com.oracle.graal.pointsto.meta.AnalysisType;
 
 import jdk.vm.ci.meta.JavaKind;
-import jdk.vm.ci.meta.JavaType;
 
 public class HostedPrimitiveType extends HostedType {
 
@@ -73,7 +72,7 @@ public final HostedType getComponentType() {
     }
 
     @Override
-    public List<JavaType> getPermittedSubclasses() {
+    public List<? extends HostedType> getPermittedSubclasses() {
         return null;
     }
 

substratevm/src/com.oracle.svm.hosted/src/com/oracle/svm/hosted/meta/HostedType.java

@@ -44,7 +44,6 @@
 import jdk.vm.ci.meta.Assumptions.AssumptionResult;
 import jdk.vm.ci.meta.JavaConstant;
 import jdk.vm.ci.meta.JavaKind;
-import jdk.vm.ci.meta.JavaType;
 import jdk.vm.ci.meta.ResolvedJavaField;
 import jdk.vm.ci.meta.ResolvedJavaMethod;
 import jdk.vm.ci.meta.ResolvedJavaRecordComponent;
@@ -67,8 +66,15 @@ public abstract class HostedType extends HostedElement implements SharedType, Wr
     private final HostedInterface[] interfaces;
 
     protected HostedArrayClass arrayType;
-    private static final List<JavaType> PERMITTED_SUBCLASSES_INIT = new ArrayList<>();
-    private List<JavaType> permittedSubclasses = PERMITTED_SUBCLASSES_INIT;
+
+    /**
+     * Sentinel marker for the uninitialized state of {@link #permittedSubclasses}. Indicates that
+     * the permitted subclasses (for sealed types) has not yet been computed. Distinguishes this
+     * state from both a computed {@code null} (not sealed) and a computed list (which may be
+     * empty).
+     */
+    private static final List<? extends HostedType> PERMITTED_SUBCLASSES_UNINITIALIZED = new ArrayList<>();
+    private List<? extends HostedType> permittedSubclasses = PERMITTED_SUBCLASSES_UNINITIALIZED;
     protected HostedType[] subTypes;
     protected HostedField[] staticFields;
 
@@ -419,12 +425,12 @@ public final HostedArrayClass getArrayClass() {
     }
 
     @Override
-    public List<JavaType> getPermittedSubclasses() {
+    public List<? extends HostedType> getPermittedSubclasses() {
         if (isPrimitive() || isArray()) {
             return null;
         }
-        if (permittedSubclasses == PERMITTED_SUBCLASSES_INIT) {
-            List<JavaType> aPermittedSubclasses = wrapped.getPermittedSubclasses();
+        if (permittedSubclasses == PERMITTED_SUBCLASSES_UNINITIALIZED) {
+            List<? extends AnalysisType> aPermittedSubclasses = wrapped.getPermittedSubclasses();
             permittedSubclasses = aPermittedSubclasses == null ? null : aPermittedSubclasses.stream().map(universe::lookup).collect(Collectors.toUnmodifiableList());
         }
         return permittedSubclasses;

substratevm/src/com.oracle.svm.hosted/src/com/oracle/svm/hosted/substitute/InjectedFieldsType.java

@@ -205,7 +205,7 @@ public ResolvedJavaType getArrayClass() {
     }
 
     @Override
-    public List<JavaType> getPermittedSubclasses() {
+    public List<? extends JavaType> getPermittedSubclasses() {
         return original.getPermittedSubclasses();
     }
 

substratevm/src/com.oracle.svm.hosted/src/com/oracle/svm/hosted/substitute/SubstitutionType.java

@@ -232,7 +232,7 @@ public ResolvedJavaType getArrayClass() {
     }
 
     @Override
-    public List<JavaType> getPermittedSubclasses() {
+    public List<? extends JavaType> getPermittedSubclasses() {
         return annotated.getPermittedSubclasses();
     }