[HHH-16772] Generated bytecode for HibernateAccessOptimizer class is invalid and causes operand stack overflow issue

hibernate-core/src/main/java/org/hibernate/bytecode/internal/bytebuddy/BytecodeProviderImpl.java

@@ -537,7 +537,10 @@ public class BytecodeProviderImpl implements BytecodeProvider {
 				);
 			}
 			methodVisitor.visitInsn( Opcodes.RETURN );
-			return new Size( 2, instrumentedMethod.getStackSize() );
+			return new Size(
+					is64BitType( type ) ? 3 : 2,
+					instrumentedMethod.getStackSize()
+			);
 		}
 
 		private int getLoadOpCode(Class<?> type) {
@@ -554,6 +557,10 @@ public class BytecodeProviderImpl implements BytecodeProvider {
 			}
 			return Opcodes.ALOAD;
 		}
+
+		private boolean is64BitType(Class<?> type) {
+			return type == long.class || type == double.class;
+		}
 	}
 
 	private List<ForeignPackageClassInfo> createForeignPackageClassInfos(Class<?> clazz) {

hibernate-core/src/test/java/org/hibernate/bytecode/internal/bytebuddy/GenerateProxiesTest.java

@@ -6,13 +6,18 @@ import static org.junit.Assert.assertNotNull;
 import java.io.IOException;
 import java.lang.reflect.InvocationTargetException;
 
+import java.util.LinkedHashMap;
+import java.util.Map;
 import org.hibernate.bytecode.enhance.internal.bytebuddy.EnhancerImpl;
 import org.hibernate.bytecode.enhance.spi.DefaultEnhancementContext;
 import org.hibernate.bytecode.enhance.spi.EnhancementException;
 import org.hibernate.bytecode.enhance.spi.Enhancer;
 import org.hibernate.bytecode.spi.ByteCodeHelper;
 import org.hibernate.bytecode.spi.ReflectionOptimizer;
+import org.hibernate.property.access.internal.PropertyAccessStrategyFieldImpl;
+import org.hibernate.property.access.spi.PropertyAccess;
 import org.hibernate.proxy.pojo.bytebuddy.ByteBuddyProxyHelper;
+import org.hibernate.testing.orm.junit.JiraKey;
 import org.junit.Test;
 
 public class GenerateProxiesTest {
@@ -43,6 +48,29 @@ public class GenerateProxiesTest {
 		assertNotNull( reflectionOptimizer.getInstantiationOptimizer().newInstance() );
 	}
 
+	@Test
+	@JiraKey("HHH-16772")
+	public void generateFastMappedSuperclassAndReflectionOptimizer() {
+		BytecodeProviderImpl bytecodeProvider  = new BytecodeProviderImpl();
+		final Map<String, PropertyAccess> propertyAccessMap = new LinkedHashMap<>();
+
+		final PropertyAccessStrategyFieldImpl propertyAccessStrategy = new PropertyAccessStrategyFieldImpl();
+
+		propertyAccessMap.put(
+				"timestamp",
+				propertyAccessStrategy.buildPropertyAccess(MappedSuperclassEntity.class, "value", true )
+		);
+
+		ReflectionOptimizer reflectionOptimizer = bytecodeProvider.getReflectionOptimizer(
+				MappedSuperclassEntity.class,
+				propertyAccessMap
+		);
+
+		assertNotNull(reflectionOptimizer);
+		assertEquals( 1, reflectionOptimizer.getAccessOptimizer().getPropertyNames().length );
+		assertNotNull( reflectionOptimizer.getInstantiationOptimizer().newInstance() );
+	}
+
 	@Test
 	public void generateEnhancedClass() throws EnhancementException, IOException {
 		Enhancer enhancer = new EnhancerImpl( new DefaultEnhancementContext(), new ByteBuddyState() );

hibernate-core/src/test/java/org/hibernate/bytecode/internal/bytebuddy/MappedSuperclassEntity.java

@@ -0,0 +1,15 @@
+/*
+ * Hibernate, Relational Persistence for Idiomatic Java
+ *
+ * License: GNU Lesser General Public License (LGPL), version 2.1 or later.
+ * See the lgpl.txt file in the root directory or <http://www.gnu.org/licenses/lgpl-2.1.html>.
+ */
+package org.hibernate.bytecode.internal.bytebuddy;
+
+import jakarta.persistence.Entity;
+import org.hibernate.bytecode.internal.bytebuddy.mappedsuperclass.BaseMappedSuperclass;
+
+@Entity
+public class MappedSuperclassEntity extends BaseMappedSuperclass {
+
+}

hibernate-core/src/test/java/org/hibernate/bytecode/internal/bytebuddy/mappedsuperclass/BaseMappedSuperclass.java

@@ -0,0 +1,19 @@
+/*
+ * Hibernate, Relational Persistence for Idiomatic Java
+ *
+ * License: GNU Lesser General Public License (LGPL), version 2.1 or later.
+ * See the lgpl.txt file in the root directory or <http://www.gnu.org/licenses/lgpl-2.1.html>.
+ */
+package org.hibernate.bytecode.internal.bytebuddy.mappedsuperclass;
+
+import jakarta.persistence.Id;
+import jakarta.persistence.MappedSuperclass;
+
+@MappedSuperclass
+public abstract class BaseMappedSuperclass {
+
+  @Id
+  protected Long id;
+
+  protected long value;
+}