Remove the old class initialization strategy

Author: Christian Wimmer

sdk/src/org.graalvm.nativeimage/src/org/graalvm/nativeimage/impl/RuntimeClassInitializationSupport.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2018, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * The Universal Permissive License (UPL), Version 1.0
@@ -46,11 +46,25 @@ public interface RuntimeClassInitializationSupport {
 
     void initializeAtBuildTime(String name, String reason);
 
-    void rerunInitialization(String name, String reason);
+    @Deprecated
+    default void rerunInitialization(String name, String reason) {
+        /*
+         * There is no more difference between initializing a class at run-time and re-running the
+         * class initializer at run time.
+         */
+        initializeAtRunTime(name, reason);
+    }
 
     void initializeAtRunTime(Class<?> aClass, String reason);
 
-    void rerunInitialization(Class<?> aClass, String reason);
+    @Deprecated
+    default void rerunInitialization(Class<?> aClass, String reason) {
+        /*
+         * There is no more difference between initializing a class at run-time and re-running the
+         * class initializer at run time.
+         */
+        initializeAtRunTime(aClass, reason);
+    }
 
     void initializeAtBuildTime(Class<?> aClass, String reason);
 }

substratevm/CHANGELOG.md

@@ -3,6 +3,7 @@
 This changelog summarizes major changes to GraalVM Native Image.
 
 ## GraalVM for JDK 23 (Internal Version 24.1.0)
+* (GR-51520) The old class initialization strategy, which was deprecated in GraalVM for JDK 22, is removed. The option `StrictImageHeap` no longer has any effect.
 * (GR-51106) Fields that are accessed via a `VarHandle` or `MethodHandle` are no longer marked as "unsafe accessed" when the `VarHandle`/`MethodHandle` can be fully intrinsified.
 * (GR-49996) Ensure explicitly set image name (e.g., via `-o imagename`) is not accidentally overwritten by `-jar jarfile` option.
 * (GR-48683) Together with Red Hat, we added partial support for the JFR event `OldObjectSample`.

substratevm/mx.substratevm/mx_substratevm.py

@@ -1547,11 +1547,7 @@ def cinterfacetutorial(args):
 
 @mx.command(suite.name, 'clinittest', 'Runs the ')
 def clinittest(args):
-    def build_and_test_clinittest_images(native_image, args=None):
-        build_and_test_clinittest_image(native_image, args, True)
-        build_and_test_clinittest_image(native_image, args, False)
-
-    def build_and_test_clinittest_image(native_image, args, new_class_init_policy):
+    def build_and_test_clinittest_image(native_image, args):
         args = [] if args is None else args
         test_cp = classpath('com.oracle.svm.test')
         build_dir = join(svmbuild_dir(), 'clinittest')
@@ -1561,11 +1557,6 @@ def build_and_test_clinittest_image(native_image, args, new_class_init_policy):
             mx.rmtree(build_dir)
         mx.ensure_dir_exists(build_dir)
 
-        if new_class_init_policy:
-            policy_args = svm_experimental_options(['-H:+SimulateClassInitializer']) + ['--features=com.oracle.svm.test.clinit.TestClassInitializationFeatureNewPolicyFeature']
-        else:
-            policy_args = svm_experimental_options(['-H:-StrictImageHeap', '-H:-SimulateClassInitializer']) + ['--features=com.oracle.svm.test.clinit.TestClassInitializationFeatureOldPolicyFeature']
-
         # Build and run the example
         binary_path = join(build_dir, 'clinittest')
         native_image([
@@ -1575,9 +1566,10 @@ def build_and_test_clinittest_image(native_image, args, new_class_init_policy):
                 '-o', binary_path,
                 '-H:+ReportExceptionStackTraces',
                 '-H:Class=com.oracle.svm.test.clinit.TestClassInitialization',
+                '--features=com.oracle.svm.test.clinit.TestClassInitializationFeature',
             ] + svm_experimental_options([
                 '-H:+PrintClassInitialization',
-            ]) + policy_args + args)
+            ]) + args)
         mx.run([binary_path])
 
         # Check the reports for initialized classes
@@ -1591,16 +1583,8 @@ def checkLine(line, marker, init_kind, msg, wrongly_initialized_lines):
                                                    "Classes marked with " + marker + " must have init kind " + init_kind + " and message " + msg)]
             with open(classes_file) as f:
                 for line in f:
-                    if new_class_init_policy:
-                        checkLine(line, "MustBeSafeEarly", "SIMULATED", "classes are initialized at run time by default", wrongly_initialized_lines)
-                        checkLine(line, "MustBeSafeLate", "SIMULATED", "classes are initialized at run time by default", wrongly_initialized_lines)
-                        checkLine(line, "MustBeSimulated", "SIMULATED", "classes are initialized at run time by default", wrongly_initialized_lines)
-                        checkLine(line, "MustBeDelayed", "RUN_TIME", "classes are initialized at run time by default", wrongly_initialized_lines)
-                    else:
-                        checkLine(line, "MustBeSafeEarly", "BUILD_TIME", "class proven as side-effect free before analysis", wrongly_initialized_lines)
-                        checkLine(line, "MustBeSafeLate", "BUILD_TIME", "class proven as side-effect free after analysis", wrongly_initialized_lines)
-                        checkLine(line, "MustBeSimulated", "RUN_TIME", "classes are initialized at run time by default", wrongly_initialized_lines)
-                        checkLine(line, "MustBeDelayed", "RUN_TIME", "classes are initialized at run time by default", wrongly_initialized_lines)
+                    checkLine(line, "MustBeSimulated", "SIMULATED", "classes are initialized at run time by default", wrongly_initialized_lines)
+                    checkLine(line, "MustBeDelayed", "RUN_TIME", "classes are initialized at run time by default", wrongly_initialized_lines)
 
                 if len(wrongly_initialized_lines) > 0:
                     msg = ""
@@ -1613,7 +1597,7 @@ def checkLine(line, marker, init_kind, msg, wrongly_initialized_lines):
 
         check_class_initialization(all_classes_file)
 
-    native_image_context_run(build_and_test_clinittest_images, args)
+    native_image_context_run(build_and_test_clinittest_image, args)
 
 
 class SubstrateJvmFuncsFallbacksBuilder(mx.Project):

substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/jdk/JNIRegistrationUtil.java

@@ -65,10 +65,10 @@ protected static boolean isWindows() {
         return Platform.includedIn(Platform.WINDOWS.class);
     }
 
-    protected static void rerunClassInit(FeatureAccess access, String... classNames) {
+    protected static void initializeAtRunTime(FeatureAccess access, String... classNames) {
         RuntimeClassInitializationSupport classInitSupport = ImageSingletons.lookup(RuntimeClassInitializationSupport.class);
         for (String className : classNames) {
-            classInitSupport.rerunInitialization(clazz(access, className), "for JDK native code support via JNI");
+            classInitSupport.initializeAtRunTime(clazz(access, className), "for JDK native code support via JNI");
         }
     }
 

substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/jdk/JavaNetHttpFeature.java

@@ -56,7 +56,7 @@ public void afterRegistration(AfterRegistrationAccess access) {
     public void duringSetup(DuringSetupAccess access) {
         RuntimeClassInitializationSupport rci = ImageSingletons.lookup(RuntimeClassInitializationSupport.class);
         rci.initializeAtRunTime("jdk.internal.net.http", "for reading properties at run time");
-        rci.rerunInitialization("jdk.internal.net.http.websocket.OpeningHandshake", "contains a SecureRandom reference");
+        rci.initializeAtRunTime("jdk.internal.net.http.websocket.OpeningHandshake", "contains a SecureRandom reference");
     }
 
     @Override

substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/jdk/RecomputedFields.java

@@ -296,7 +296,7 @@ private void processFieldUpdater(Object updater) {
 class InnocuousForkJoinWorkerThreadFeature implements InternalFeature {
     @Override
     public void duringSetup(DuringSetupAccess access) {
-        ImageSingletons.lookup(RuntimeClassInitializationSupport.class).rerunInitialization(access.findClassByName("java.util.concurrent.ForkJoinWorkerThread$InnocuousForkJoinWorkerThread"),
+        ImageSingletons.lookup(RuntimeClassInitializationSupport.class).initializeAtRunTime(access.findClassByName("java.util.concurrent.ForkJoinWorkerThread$InnocuousForkJoinWorkerThread"),
                         "innocuousThreadGroup must be initialized at run time");
     }
 }

substratevm/src/com.oracle.svm.hosted/src/com/oracle/svm/hosted/NativeImageGenerator.java

@@ -894,7 +894,7 @@ protected void setupNativeImage(OptionValues options, Map<Method, CEntryPointDat
                 ImageSingletons.add(LinkAtBuildTimeSupport.class, new LinkAtBuildTimeSupport(loader, classLoaderSupport));
                 ImageSingletons.add(ObservableImageHeapMapProvider.class, new ObservableImageHeapMapProviderImpl());
 
-                ClassInitializationSupport classInitializationSupport = ClassInitializationSupport.create(originalMetaAccess, loader);
+                ClassInitializationSupport classInitializationSupport = new ClassInitializationSupport(originalMetaAccess, loader);
                 ImageSingletons.add(RuntimeClassInitializationSupport.class, classInitializationSupport);
                 ClassInitializationFeature.processClassInitializationOptions(classInitializationSupport);
 

substratevm/src/com.oracle.svm.hosted/src/com/oracle/svm/hosted/SVMHost.java

@@ -32,11 +32,9 @@
 import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
 import java.lang.reflect.Modifier;
-import java.util.Collections;
 import java.util.Comparator;
 import java.util.EnumSet;
 import java.util.HashMap;
-import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
 import java.util.Optional;
@@ -76,11 +74,9 @@
 import com.oracle.svm.core.SubstrateOptions.OptimizationLevel;
 import com.oracle.svm.core.annotate.InjectAccessors;
 import com.oracle.svm.core.c.CGlobalData;
-import com.oracle.svm.core.classinitialization.EnsureClassInitializedNode;
 import com.oracle.svm.core.graal.meta.SubstrateForeignCallLinkage;
 import com.oracle.svm.core.graal.meta.SubstrateForeignCallsProvider;
 import com.oracle.svm.core.graal.stackvalue.StackValueNode;
-import com.oracle.svm.core.graal.thread.VMThreadLocalAccess;
 import com.oracle.svm.core.heap.StoredContinuation;
 import com.oracle.svm.core.heap.Target_java_lang_ref_Reference;
 import com.oracle.svm.core.heap.UnknownClass;
@@ -130,11 +126,8 @@
 import jdk.graal.compiler.nodes.StaticDeoptimizingNode;
 import jdk.graal.compiler.nodes.StructuredGraph;
 import jdk.graal.compiler.nodes.ValueNode;
-import jdk.graal.compiler.nodes.extended.UnsafeAccessNode;
 import jdk.graal.compiler.nodes.graphbuilderconf.GraphBuilderConfiguration;
 import jdk.graal.compiler.nodes.graphbuilderconf.IntrinsicContext;
-import jdk.graal.compiler.nodes.java.AccessFieldNode;
-import jdk.graal.compiler.nodes.java.AccessMonitorNode;
 import jdk.graal.compiler.options.Option;
 import jdk.graal.compiler.options.OptionKey;
 import jdk.graal.compiler.options.OptionValues;
@@ -170,8 +163,6 @@ public class SVMHost extends HostVM {
      * need to keep the whole graphs alive.
      */
     private final ConcurrentMap<AnalysisMethod, Boolean> containsStackValueNode = new ConcurrentHashMap<>();
-    private final ConcurrentMap<AnalysisMethod, Boolean> classInitializerSideEffect = new ConcurrentHashMap<>();
-    private final ConcurrentMap<AnalysisMethod, Set<AnalysisType>> initializedClasses = new ConcurrentHashMap<>();
     private final ConcurrentMap<AnalysisMethod, Boolean> analysisTrivialMethods = new ConcurrentHashMap<>();
 
     private final Set<AnalysisField> finalFieldsInitializedOutsideOfConstructor = ConcurrentHashMap.newKeySet();
@@ -642,53 +633,6 @@ public void methodBeforeTypeFlowCreationHook(BigBang bb, AnalysisMethod method,
             } else if (n instanceof ReachabilityRegistrationNode node) {
                 bb.postTask(debug -> node.getRegistrationTask().ensureDone());
             }
-            checkClassInitializerSideEffect(method, n);
-        }
-    }
-
-    /**
-     * Classes are only safe for automatic initialization if the class initializer has no side
-     * effect on other classes and cannot be influenced by other classes. Otherwise there would be
-     * observable side effects. For example, if a class initializer of class A writes a static field
-     * B.f in class B, then someone could rely on reading the old value of B.f before triggering
-     * initialization of A. Similarly, if a class initializer of class A reads a static field B.f,
-     * then an early automatic initialization of class A could read a non-yet-set value of B.f.
-     *
-     * Note that it is not necessary to disallow instance field accesses: Objects allocated by the
-     * class initializer itself can always be accessed because they are independent from other
-     * initializers; all other objects must be loaded transitively from a static field.
-     *
-     * Currently, we are conservative and mark all methods that access static fields as unsafe for
-     * automatic class initialization (unless the class initializer itself accesses a static field
-     * of its own class - the common way of initializing static fields). The check could be relaxed
-     * by tracking the call chain, i.e., allowing static field accesses when the root method of the
-     * call chain is the class initializer. But this does not fit well into the current approach
-     * where each method has a `Safety` flag.
-     */
-    private void checkClassInitializerSideEffect(AnalysisMethod method, Node n) {
-        if (n instanceof AccessFieldNode) {
-            ResolvedJavaField field = ((AccessFieldNode) n).field();
-            if (field.isStatic() && (!method.isClassInitializer() || !field.getDeclaringClass().equals(method.getDeclaringClass()))) {
-                classInitializerSideEffect.put(method, true);
-            }
-        } else if (n instanceof UnsafeAccessNode || n instanceof VMThreadLocalAccess) {
-            /*
-             * Unsafe memory access nodes are rare, so it does not pay off to check what kind of
-             * field they are accessing.
-             *
-             * Methods that access a thread-local value cannot be initialized at image build time
-             * because such values are not available yet.
-             */
-            classInitializerSideEffect.put(method, true);
-        } else if (n instanceof EnsureClassInitializedNode) {
-            ResolvedJavaType type = ((EnsureClassInitializedNode) n).constantTypeOrNull(getProviders(method.getMultiMethodKey()).getConstantReflection());
-            if (type != null) {
-                initializedClasses.computeIfAbsent(method, k -> new HashSet<>()).add((AnalysisType) type);
-            } else {
-                classInitializerSideEffect.put(method, true);
-            }
-        } else if (n instanceof AccessMonitorNode) {
-            classInitializerSideEffect.put(method, true);
         }
     }
 
@@ -707,19 +651,6 @@ public boolean containsStackValueNode(AnalysisMethod method) {
         return containsStackValueNode.containsKey(method);
     }
 
-    public boolean hasClassInitializerSideEffect(AnalysisMethod method) {
-        return classInitializerSideEffect.containsKey(method);
-    }
-
-    public Set<AnalysisType> getInitializedClasses(AnalysisMethod method) {
-        Set<AnalysisType> result = initializedClasses.get(method);
-        if (result != null) {
-            return result;
-        } else {
-            return Collections.emptySet();
-        }
-    }
-
     public boolean isAnalysisTrivialMethod(AnalysisMethod method) {
         return analysisTrivialMethods.containsKey(method);
     }