Make CGlobalDataBasePointer layer aware to ensure the base corresponding to the correct layer is used when accessing CGlobalData

Zeavee · Zeavee · commit db0006f6059a · 2025-09-23T18:02:48.000+02:00
diff --git a/substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/CGlobalDataPointerSingleton.java b/substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/CGlobalDataPointerSingleton.java
@@ -0,0 +1,77 @@
+/*
+ * Copyright (c) 2025, 2025, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+package com.oracle.svm.core;
+
+import java.util.EnumSet;
+
+import org.graalvm.nativeimage.Platform;
+import org.graalvm.nativeimage.Platforms;
+
+import com.oracle.svm.core.c.BoxedRelocatedPointer;
+import com.oracle.svm.core.feature.AutomaticallyRegisteredImageSingleton;
+import com.oracle.svm.core.graal.code.CGlobalDataBasePointer;
+import com.oracle.svm.core.layeredimagesingleton.ImageSingletonWriter;
+import com.oracle.svm.core.layeredimagesingleton.LayeredImageSingletonBuilderFlags;
+import com.oracle.svm.core.layeredimagesingleton.LayeredImageSingletonSupport;
+import com.oracle.svm.core.layeredimagesingleton.MultiLayeredImageSingleton;
+
+/**
+ * This singleton contains the {@link CGlobalDataBasePointer} of the current layer. In layered
+ * images, there is one {@link com.oracle.svm.core.c.CGlobalData} memory space for each layer, so
+ * when reading a {@link com.oracle.svm.core.c.CGlobalData}, the corresponding base needs to be
+ * used.
+ */
+@AutomaticallyRegisteredImageSingleton
+public class CGlobalDataPointerSingleton implements MultiLayeredImageSingleton {
+
+    /**
+     * Image heap object storing the base address of CGlobalData memory using a relocation. Before
+     * the image heap is set up, CGlobalData must be accessed via relocations in the code instead.
+     */
+    private final BoxedRelocatedPointer cGlobalDataRuntimeBaseAddress = new BoxedRelocatedPointer(CGlobalDataBasePointer.INSTANCE);
+
+    @Platforms(Platform.HOSTED_ONLY.class)
+    public static CGlobalDataPointerSingleton currentLayer() {
+        return LayeredImageSingletonSupport.singleton().lookup(CGlobalDataPointerSingleton.class, false, true);
+    }
+
+    public static CGlobalDataPointerSingleton[] allLayers() {
+        return MultiLayeredImageSingleton.getAllLayers(CGlobalDataPointerSingleton.class);
+    }
+
+    public BoxedRelocatedPointer getRuntimeBaseAddress() {
+        return cGlobalDataRuntimeBaseAddress;
+    }
+
+    @Override
+    public EnumSet<LayeredImageSingletonBuilderFlags> getImageBuilderFlags() {
+        return LayeredImageSingletonBuilderFlags.ALL_ACCESS;
+    }
+
+    @Override
+    public PersistFlags preparePersist(ImageSingletonWriter writer) {
+        return PersistFlags.NOTHING;
+    }
+}
diff --git a/substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/SubstrateDiagnostics.java b/substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/SubstrateDiagnostics.java
@@ -50,6 +50,7 @@
 import com.oracle.svm.core.SubstrateDiagnostics.DumpDeoptStubPointer;
 import com.oracle.svm.core.SubstrateDiagnostics.DumpRecentDeoptimizations;
 import com.oracle.svm.core.SubstrateDiagnostics.DumpRuntimeCodeInfoMemory;
+import com.oracle.svm.core.c.BoxedRelocatedPointer;
 import com.oracle.svm.core.c.NonmovableArrays;
 import com.oracle.svm.core.code.CodeInfo;
 import com.oracle.svm.core.code.CodeInfoAccess;
@@ -67,7 +68,6 @@
 import com.oracle.svm.core.feature.AutomaticallyRegisteredImageSingleton;
 import com.oracle.svm.core.feature.InternalFeature;
 import com.oracle.svm.core.graal.RuntimeCompilation;
-import com.oracle.svm.core.graal.code.CGlobalDataInfo;
 import com.oracle.svm.core.graal.stackvalue.UnsafeStackValue;
 import com.oracle.svm.core.heap.Heap;
 import com.oracle.svm.core.heap.RestrictHeapAccess;
@@ -912,7 +912,15 @@ public void printDiagnostics(Log log, ErrorContext context, int maxDiagnosticLev
             if (SubstrateOptions.useRelativeCodePointers()) {
                 log.string("Code base: ").zhex(KnownIntrinsics.codeBase()).newline();
             }
-            log.string("CGlobalData base: ").zhex(CGlobalDataInfo.CGLOBALDATA_RUNTIME_BASE_ADDRESS.getPointer()).newline();
+            CGlobalDataPointerSingleton[] layeredSingletons = CGlobalDataPointerSingleton.allLayers();
+            if (ImageLayerBuildingSupport.buildingImageLayer()) {
+                for (int i = 0; i < layeredSingletons.length; ++i) {
+                    log.string("CGlobalData base for layer ").unsigned(i).string(": ").zhex(layeredSingletons[i].getRuntimeBaseAddress().getPointer()).newline();
+                }
+            } else {
+                BoxedRelocatedPointer baseAddress = layeredSingletons[0].getRuntimeBaseAddress();
+                log.string("CGlobalData base: ").zhex(baseAddress.getPointer()).newline();
+            }
             log.string("Containerized: ").bool(Container.singleton().isContainerized()).newline();
 
             if (Container.singleton().isContainerized()) {
diff --git a/substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/graal/code/CGlobalDataInfo.java b/substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/graal/code/CGlobalDataInfo.java
@@ -32,7 +32,6 @@
 
 import com.oracle.svm.core.BuildPhaseProvider.AfterHeapLayout;
 import com.oracle.svm.core.BuildPhaseProvider.AfterHostedUniverse;
-import com.oracle.svm.core.c.BoxedRelocatedPointer;
 import com.oracle.svm.core.c.CGlobalDataImpl;
 import com.oracle.svm.core.heap.UnknownPrimitiveField;
 import com.oracle.svm.core.util.VMError;
@@ -43,12 +42,6 @@
  * {@link CGlobalDataImpl} within static fields.
  */
 public final class CGlobalDataInfo {
-    /**
-     * Image heap object storing the base address of CGlobalData memory using a relocation. Before
-     * the image heap is set up, CGlobalData must be accessed via relocations in the code instead.
-     */
-    public static final BoxedRelocatedPointer CGLOBALDATA_RUNTIME_BASE_ADDRESS = new BoxedRelocatedPointer(CGlobalDataBasePointer.INSTANCE);
-
     private final CGlobalDataImpl<?> data;
     private final boolean isSymbolReference;
 
@@ -68,13 +61,16 @@ public final class CGlobalDataInfo {
     /** Cache until writing the image in case the {@link Supplier} is costly or has side-effects. */
     @Platforms(HOSTED_ONLY.class) private byte[] bytes;
 
+    private final int layerNum;
+
     @Platforms(Platform.HOSTED_ONLY.class)
-    public CGlobalDataInfo(CGlobalDataImpl<?> data, boolean definedAsGlobalInPriorLayer) {
+    public CGlobalDataInfo(CGlobalDataImpl<?> data, boolean definedAsGlobalInPriorLayer, int layerNum) {
         assert data != null;
         this.data = data;
         this.isSymbolReference = data.isSymbolReference();
         assert !this.isSymbolReference || data.symbolName != null;
         this.definedAsGlobalInPriorLayer = definedAsGlobalInPriorLayer;
+        this.layerNum = layerNum;
     }
 
     public CGlobalDataImpl<?> getData() {
diff --git a/substratevm/src/com.oracle.svm.hosted/src/com/oracle/svm/hosted/c/CGlobalDataFeature.java b/substratevm/src/com.oracle.svm.hosted/src/com/oracle/svm/hosted/c/CGlobalDataFeature.java
@@ -40,6 +40,7 @@
 import org.graalvm.nativeimage.ImageSingletons;
 
 import com.oracle.graal.pointsto.meta.AnalysisType;
+import com.oracle.svm.core.CGlobalDataPointerSingleton;
 import com.oracle.svm.core.ParsingReason;
 import com.oracle.svm.core.c.BoxedRelocatedPointer;
 import com.oracle.svm.core.c.CGlobalData;
@@ -50,14 +51,17 @@
 import com.oracle.svm.core.feature.InternalFeature;
 import com.oracle.svm.core.graal.code.CGlobalDataInfo;
 import com.oracle.svm.core.graal.nodes.CGlobalDataLoadAddressNode;
+import com.oracle.svm.core.imagelayer.DynamicImageLayerInfo;
 import com.oracle.svm.core.imagelayer.ImageLayerBuildingSupport;
 import com.oracle.svm.core.traits.BuiltinTraits.BuildtimeAccessOnly;
 import com.oracle.svm.core.traits.BuiltinTraits.NoLayeredCallbacks;
 import com.oracle.svm.core.traits.SingletonLayeredInstallationKind.Independent;
 import com.oracle.svm.core.traits.SingletonTraits;
 import com.oracle.svm.core.util.VMError;
+import com.oracle.svm.hosted.FeatureImpl;
 import com.oracle.svm.hosted.image.RelocatableBuffer;
 import com.oracle.svm.hosted.imagelayer.CodeLocation;
+import com.oracle.svm.hosted.imagelayer.LoadImageSingletonFeature;
 import com.oracle.svm.hosted.meta.HostedSnippetReflectionProvider;
 import com.oracle.svm.util.ReflectionUtil;
 
@@ -90,10 +94,12 @@
 import jdk.graal.compiler.nodes.graphbuilderconf.InvocationPlugin.RequiredInvocationPlugin;
 import jdk.graal.compiler.nodes.graphbuilderconf.InvocationPlugins.Registration;
 import jdk.graal.compiler.nodes.java.LoadFieldNode;
+import jdk.graal.compiler.nodes.java.LoadIndexedNode;
 import jdk.graal.compiler.nodes.memory.ReadNode;
 import jdk.graal.compiler.nodes.memory.address.OffsetAddressNode;
 import jdk.graal.compiler.phases.util.Providers;
 import jdk.vm.ci.meta.JavaConstant;
+import jdk.vm.ci.meta.JavaKind;
 import jdk.vm.ci.meta.ResolvedJavaField;
 import jdk.vm.ci.meta.ResolvedJavaMethod;
 import jdk.vm.ci.meta.ResolvedJavaType;
@@ -103,6 +109,8 @@
 public class CGlobalDataFeature implements InternalFeature {
 
     private final Method getCGlobalDataInfoMethod = ReflectionUtil.lookupMethod(CGlobalDataNonConstantRegistry.class, "getCGlobalDataInfo", CGlobalDataImpl.class);
+    private final Field layerNumField = ReflectionUtil.lookupField(CGlobalDataInfo.class, "layerNum");
+    private final Field cGlobalDataRuntimeBaseAddressField = ReflectionUtil.lookupField(CGlobalDataPointerSingleton.class, "cGlobalDataRuntimeBaseAddress");
     private final Field offsetField = ReflectionUtil.lookupField(CGlobalDataInfo.class, "offset");
     private final Field isSymbolReferenceField = ReflectionUtil.lookupField(CGlobalDataInfo.class, "isSymbolReference");
     private final Field baseHolderPointerField = ReflectionUtil.lookupField(BoxedRelocatedPointer.class, "pointer");
@@ -132,6 +140,17 @@ public void duringSetup(DuringSetupAccess a) {
         a.registerObjectReplacer(this::replaceObject);
     }
 
+    @Override
+    public void beforeAnalysis(BeforeAnalysisAccess access) {
+        if (ImageLayerBuildingSupport.buildingImageLayer()) {
+            /*
+             * The non-constant registry needs to be rescanned in layered images to make sure it is
+             * always reachable in every layer and that all the data is properly tracked.
+             */
+            ((FeatureImpl.BeforeAnalysisAccessImpl) access).rescanObject(nonConstantRegistry);
+        }
+    }
+
     @Override
     public void afterHeapLayout(AfterHeapLayoutAccess access) {
         layout();
@@ -180,8 +199,39 @@ public boolean apply(GraphBuilderContext b, ResolvedJavaMethod targetMethod, Rec
                         }
                     }
 
-                    JavaConstant baseHolderConstant = providers.getSnippetReflection().forObject(CGlobalDataInfo.CGLOBALDATA_RUNTIME_BASE_ADDRESS);
-                    ConstantNode baseHolder = ConstantNode.forConstant(baseHolderConstant, b.getMetaAccess(), b.getGraph());
+                    ValueNode baseHolder;
+                    if (ImageLayerBuildingSupport.buildingImageLayer()) {
+                        /*
+                         * When building layered images, each layer has its own CGlobalData base
+                         * pointer, meaning the one associated with this specific CGlobalDataInfo
+                         * needs to be used.
+                         */
+                        JavaConstant cGlobalDataPointerSingletonClass = providers.getSnippetReflection().forObject(CGlobalDataPointerSingleton.class);
+                        ConstantNode classConstant = ConstantNode.forConstant(cGlobalDataPointerSingletonClass, b.getMetaAccess(), b.getGraph());
+
+                        /* Load the array containing all the singletons. */
+                        ValueNode layers = b.add(ImageSingletons.lookup(LoadImageSingletonFeature.class).loadMultiLayeredImageSingleton(b, classConstant));
+
+                        /*
+                         * Get the layer number of the CGlobalDataInfo to get the index to use in
+                         * the singleton array.
+                         */
+                        ValueNode layerNum = b.add(LoadFieldNode.create(b.getAssumptions(), info, b.getMetaAccess().lookupJavaField(layerNumField)));
+
+                        /* Use the layer number to get the corresponding singleton. */
+                        ValueNode singleton = b.add(LoadIndexedNode.create(b.getAssumptions(), layers, layerNum, null, JavaKind.Object, b.getMetaAccess(), b.getConstantReflection()));
+
+                        /* Get the CGlobalData base pointer from the singleton. */
+                        baseHolder = b.add(LoadFieldNode.create(b.getAssumptions(), singleton, b.getMetaAccess().lookupJavaField(cGlobalDataRuntimeBaseAddressField)));
+                    } else {
+                        /*
+                         * In standalone image, there is only one CGlobalData base pointer, so there
+                         * is no need to have a custom access.
+                         */
+                        JavaConstant baseHolderConstant = providers.getSnippetReflection().forObject(CGlobalDataPointerSingleton.currentLayer().getRuntimeBaseAddress());
+                        baseHolder = ConstantNode.forConstant(baseHolderConstant, b.getMetaAccess(), b.getGraph());
+                    }
+
                     ResolvedJavaField holderPointerField = providers.getMetaAccess().lookupJavaField(baseHolderPointerField);
                     StampPair pointerStamp = StampPair.createSingle(providers.getWordTypes().getWordStamp((ResolvedJavaType) holderPointerField.getType()));
                     LoadFieldNode baseAddress = b.add(LoadFieldNode.createOverrideStamp(pointerStamp, baseHolder, holderPointerField));
@@ -270,7 +320,7 @@ CGlobalDataInfo createCGlobalDataInfo(CGlobalDataImpl<?> data, boolean definedAs
                             "We currently do not allow CGlobalData code locations to be in a hidden class. Please adapt the code accordingly. Location: %s",
                             data.codeLocation);
         }
-        CGlobalDataInfo cGlobalDataInfo = new CGlobalDataInfo(data, definedAsGlobalInPriorLayer);
+        CGlobalDataInfo cGlobalDataInfo = new CGlobalDataInfo(data, definedAsGlobalInPriorLayer, DynamicImageLayerInfo.getCurrentLayerNumber());
         if (data.nonConstant) {
             nonConstantRegistry.registerNonConstantSymbol(cGlobalDataInfo);
         }
diff --git a/substratevm/src/com.oracle.svm.hosted/src/com/oracle/svm/hosted/imagelayer/LoadImageSingletonFeature.java b/substratevm/src/com.oracle.svm.hosted/src/com/oracle/svm/hosted/imagelayer/LoadImageSingletonFeature.java
@@ -37,7 +37,6 @@
 import java.util.Objects;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.function.BiConsumer;
-import java.util.function.BiFunction;
 import java.util.function.Consumer;
 
 import org.graalvm.nativeimage.AnnotationAccess;
@@ -128,29 +127,13 @@ public boolean isInConfiguration(IsInConfigurationAccess access) {
 
     @Override
     public void registerInvocationPlugins(Providers providers, GraphBuilderConfiguration.Plugins plugins, ParsingReason reason) {
-        BiFunction<GraphBuilderContext, ValueNode, ValueNode> loadMultiLayeredImageSingleton = (b, classNode) -> {
-            Class<?> key = b.getSnippetReflection().asObject(Class.class, classNode.asJavaConstant());
-
-            if (ImageLayerBuildingSupport.buildingSharedLayer()) {
-                /*
-                 * Load reference to the proper slot within the cross-layer singleton table.
-                 */
-                return LoadImageSingletonFactory.loadLayeredImageSingleton(key, b.getMetaAccess());
-            } else {
-                /*
-                 * Can directly load the array of all objects
-                 */
-                JavaConstant multiLayerArray = getMultiLayerConstant(key, b.getMetaAccess(), b.getSnippetReflection());
-                return ConstantNode.forConstant(multiLayerArray, 1, true, b.getMetaAccess());
-            }
-        };
 
         InvocationPlugins.Registration r = new InvocationPlugins.Registration(plugins.getInvocationPlugins(), MultiLayeredImageSingleton.class);
         r.register(new InvocationPlugin.RequiredInvocationPlugin("getAllLayers", Class.class) {
 
             @Override
             public boolean apply(GraphBuilderContext b, ResolvedJavaMethod targetMethod, Receiver unused, ValueNode classNode) {
-                b.addPush(JavaKind.Object, loadMultiLayeredImageSingleton.apply(b, classNode));
+                b.addPush(JavaKind.Object, loadMultiLayeredImageSingleton(b, classNode));
                 return true;
             }
         });
@@ -159,7 +142,7 @@ public boolean apply(GraphBuilderContext b, ResolvedJavaMethod targetMethod, Rec
             @Override
             public boolean apply(GraphBuilderContext b, ResolvedJavaMethod targetMethod, Receiver unused, ValueNode classNode, ValueNode indexNode) {
                 try (InvocationPluginHelper helper = new InvocationPluginHelper(b, targetMethod)) {
-                    ValueNode layerArray = b.add(loadMultiLayeredImageSingleton.apply(b, classNode));
+                    ValueNode layerArray = b.add(loadMultiLayeredImageSingleton(b, classNode));
 
                     helper.intrinsicArrayRangeCheck(layerArray, indexNode, ConstantNode.forInt(1));
                     var arrayElem = LoadIndexedNode.create(null, layerArray, indexNode, null, JavaKind.Object, b.getMetaAccess(), b.getConstantReflection());
@@ -181,6 +164,23 @@ static void checkAllowNullEntries(Class<?> key) {
                         "This MultiLayeredSingleton requires an entry to be installed in every layer. Please see the javadoc within MultiLayeredAllowNullEntries for more details.");
     }
 
+    public ValueNode loadMultiLayeredImageSingleton(GraphBuilderContext b, ValueNode classNode) {
+        Class<?> key = b.getSnippetReflection().asObject(Class.class, classNode.asJavaConstant());
+
+        if (ImageLayerBuildingSupport.buildingSharedLayer()) {
+            /*
+             * Load reference to the proper slot within the cross-layer singleton table.
+             */
+            return LoadImageSingletonFactory.loadLayeredImageSingleton(key, b.getMetaAccess());
+        } else {
+            /*
+             * Can directly load the array of all objects
+             */
+            JavaConstant multiLayerArray = getMultiLayerConstant(key, b.getMetaAccess(), b.getSnippetReflection());
+            return ConstantNode.forConstant(multiLayerArray, 1, true, b.getMetaAccess());
+        }
+    }
+
     /**
      * This method needs to be called after all image singletons are registered. Currently, some
      * singletons are registered in
