Image size: stuff preserved bit into existing bitsets for JNI methods/fields

Author: DSouzaM

substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/jni/access/JNIAccessibleClass.java

@@ -39,21 +39,21 @@
 /**
  * Information on a class that can be looked up and accessed via JNI.
  */
-public final class JNIAccessibleClass extends JNIAccessibleElement {
+public final class JNIAccessibleClass implements PreservableJNIElement {
     private final Class<?> classObject;
     private EconomicMap<JNIAccessibleMethodDescriptor, JNIAccessibleMethod> methods;
     private EconomicMap<CharSequence, JNIAccessibleField> fields;
+    private boolean preserved;
 
     @Platforms(HOSTED_ONLY.class)
     public JNIAccessibleClass(Class<?> clazz, boolean preserved) {
-        super(preserved);
         assert clazz != null;
         this.classObject = clazz;
+        this.preserved = preserved;
     }
 
     @Platforms(HOSTED_ONLY.class)
     JNIAccessibleClass() {
-        super(false);
         /* For negative queries */
         this.classObject = null;
     }
@@ -127,4 +127,17 @@ public JNIAccessibleMethod getMethod(JNIAccessibleMethodDescriptor descriptor) {
     String getJNIName() {
         return ClassNameSupport.reflectionNameToJNIName(classObject.getName());
     }
+
+    @Override
+    public boolean isPreserved() {
+        return preserved;
+    }
+
+    @Override
+    public void reportReregistered(boolean updatedPreserved) {
+        // State can only ever go from "preserved" to "not preserved".
+        if (!updatedPreserved) {
+            this.preserved = false;
+        }
+    }
 }

substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/jni/access/JNIAccessibleField.java

@@ -47,21 +47,21 @@
 /**
  * Information on a field that can be looked up and accessed via JNI.
  */
-public final class JNIAccessibleField extends JNIAccessibleMember {
+public final class JNIAccessibleField extends JNIAccessibleMember implements PreservableJNIElement {
     /* 10000000...0 */
     private static final UnsignedWord ID_STATIC_FLAG = Word.unsigned(-1L).unsignedShiftRight(1).add(1);
     /* 01000000...0 */
-    private static final UnsignedWord ID_OBJECT_FLAG = ID_STATIC_FLAG.unsignedShiftRight(1);
+    private static final UnsignedWord ID_PRESERVED_FLAG = ID_STATIC_FLAG.unsignedShiftRight(1);
     /* 00100000...0 */
-    private static final UnsignedWord ID_NEGATIVE_FLAG = ID_OBJECT_FLAG.unsignedShiftRight(1);
+    private static final UnsignedWord ID_NEGATIVE_FLAG = ID_PRESERVED_FLAG.unsignedShiftRight(1);
     /* 00010000...0 */
     private static final UnsignedWord ID_LAYER_NUMBER_MASK = ID_NEGATIVE_FLAG.unsignedShiftRight(1);
     private static final int ID_LAYER_NUMBER_SHIFT = 60;
     /* 00001111...1 */
     private static final UnsignedWord ID_OFFSET_MASK = ID_LAYER_NUMBER_MASK.subtract(1);
 
     public static JNIAccessibleField negativeFieldQuery(JNIAccessibleClass jniClass) {
-        return new JNIAccessibleField(false, jniClass, null, 0);
+        return new JNIAccessibleField(jniClass, null, 0, false);
     }
 
     /**
@@ -99,31 +99,33 @@ private static int getLayerNumberFromId(UnsignedWord id) {
         }
     }
 
-    @Platforms(HOSTED_ONLY.class) private final UnsignedWord flags;
+    @Platforms(HOSTED_ONLY.class) private UnsignedWord flags;
 
     /**
      * Represents the {@link JNIFieldId} of the field.
      *
      * From left (MSB) to right (LSB):
      * <ul>
      * <li>1 bit for a flag indicating whether the field is static</li>
-     * <li>1 bit for a flag indicating whether the field is an object reference</li>
+     * <li>1 bit for a flag indicating whether the field is preserved</li>
      * <li>1 bit for a flag indicating whether the field is a negative query</li>
-     * <li>Remaining 61 bits for (unsigned) offset in the object</li>
+     * <li>1 bit for an unsigned integer indicating the layer number</li>
+     * <li>Remaining 60 bits for (unsigned) offset in the object</li>
      * </ul>
      */
     @UnknownPrimitiveField(availability = ReadyForCompilation.class)//
     private UnsignedWord id = Word.zero();
 
     @Platforms(HOSTED_ONLY.class)
-    public JNIAccessibleField(boolean preserved, JNIAccessibleClass declaringClass, JavaKind kind, int modifiers) {
-        super(preserved, declaringClass);
+    public JNIAccessibleField(JNIAccessibleClass declaringClass, JavaKind kind, int modifiers, boolean preserved) {
+        super(declaringClass);
 
         UnsignedWord bits = Modifier.isStatic(modifiers) ? ID_STATIC_FLAG : Word.zero();
         if (kind == null) {
             bits = bits.or(ID_NEGATIVE_FLAG);
-        } else if (kind.isObject()) {
-            bits = bits.or(ID_OBJECT_FLAG);
+        }
+        if (preserved) {
+            bits = bits.or(ID_PRESERVED_FLAG);
         }
         this.flags = bits;
     }
@@ -161,4 +163,18 @@ public void finishBeforeCompilation(int offset, int layerNumber, EconomicSet<Cla
         }
         setHidingSubclasses(hidingSubclasses);
     }
+
+    @Override
+    public boolean isPreserved() {
+        return id.and(ID_PRESERVED_FLAG).notEqual(0);
+    }
+
+    @Platforms(HOSTED_ONLY.class)
+    @Override
+    public void reportReregistered(boolean updatedPreserved) {
+        // State can only ever go from "preserved" to "not preserved".
+        if (!updatedPreserved) {
+            flags = flags.and(ID_PRESERVED_FLAG.not());
+        }
+    }
 }

substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/jni/access/JNIAccessibleMember.java

@@ -31,14 +31,13 @@
 import com.oracle.svm.core.BuildPhaseProvider.ReadyForCompilation;
 import com.oracle.svm.core.heap.UnknownObjectField;
 
-abstract class JNIAccessibleMember extends JNIAccessibleElement {
+abstract class JNIAccessibleMember {
     private final JNIAccessibleClass declaringClass;
 
     @UnknownObjectField(fullyQualifiedTypes = "org.graalvm.collections.EconomicMapImpl", canBeNull = true, availability = ReadyForCompilation.class) //
     private EconomicSet<Class<?>> hidingSubclasses;
 
-    JNIAccessibleMember(boolean preserved, JNIAccessibleClass declaringClass) {
-        super(preserved);
+    JNIAccessibleMember(JNIAccessibleClass declaringClass) {
         this.declaringClass = declaringClass;
     }
 

substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/jni/access/JNIAccessibleMethod.java

@@ -48,7 +48,7 @@
 /**
  * Information on a method that can be looked up and called via JNI.
  */
-public final class JNIAccessibleMethod extends JNIAccessibleMember {
+public final class JNIAccessibleMethod extends JNIAccessibleMember implements PreservableJNIElement {
     public static final int VTABLE_INDEX_STATICALLY_BOUND_METHOD = -1;
     public static final int VTABLE_INDEX_NOT_YET_COMPUTED = -2;
     public static final int INTERFACE_TYPEID_CLASS_TABLE = -1;
@@ -57,7 +57,7 @@ public final class JNIAccessibleMethod extends JNIAccessibleMember {
     public static final int NEW_OBJECT_TARGET_INVALID_FOR_ABSTRACT_TYPE = -1;
 
     public static JNIAccessibleMethod negativeMethodQuery(JNIAccessibleClass jniClass) {
-        return new JNIAccessibleMethod(false, jniClass, RuntimeMetadataDecoderImpl.NEGATIVE_FLAG_MASK);
+        return new JNIAccessibleMethod(jniClass, RuntimeMetadataDecoderImpl.NEGATIVE_FLAG_MASK, false);
     }
 
     @Platforms(HOSTED_ONLY.class)
@@ -79,7 +79,7 @@ public static ResolvedJavaField getCallVariantWrapperField(MetaAccessProvider me
         return metaAccess.lookupJavaField(ReflectionUtil.lookupField(JNIAccessibleMethod.class, name.toString()));
     }
 
-    private final int modifiers;
+    private int modifiers;
     @UnknownPrimitiveField(availability = ReadyForCompilation.class)//
     private int vtableIndex = VTABLE_INDEX_NOT_YET_COMPUTED;
     @UnknownPrimitiveField(availability = ReadyForCompilation.class)//
@@ -104,9 +104,10 @@ public static ResolvedJavaField getCallVariantWrapperField(MetaAccessProvider me
     @SuppressWarnings("unused") private CodePointer valistNonvirtualWrapper;
 
     @Platforms(HOSTED_ONLY.class)
-    public JNIAccessibleMethod(boolean preserved, JNIAccessibleClass declaringClass, int modifiers) {
-        super(preserved, declaringClass);
-        this.modifiers = modifiers;
+    public JNIAccessibleMethod(JNIAccessibleClass declaringClass, int modifiers, boolean preserved) {
+        super(declaringClass);
+        assert (modifiers & RuntimeMetadataDecoderImpl.PRESERVED_FLAG_MASK) == 0;
+        this.modifiers = modifiers | (preserved ? RuntimeMetadataDecoderImpl.PRESERVED_FLAG_MASK : 0);
     }
 
     @Uninterruptible(reason = "Called from uninterruptible code.", mayBeInlined = true)
@@ -172,4 +173,17 @@ public void finishBeforeCompilation(EconomicSet<Class<?>> hidingSubclasses, int
         this.valistNonvirtualWrapper = valistNonvirtual;
         setHidingSubclasses(hidingSubclasses);
     }
+
+    @Override
+    public boolean isPreserved() {
+        return (modifiers & RuntimeMetadataDecoderImpl.PRESERVED_FLAG_MASK) != 0;
+    }
+
+    @Override
+    public void reportReregistered(boolean updatedPreserved) {
+        // State can only ever go from "preserved" to "not preserved".
+        if (!updatedPreserved) {
+            modifiers = modifiers & (~RuntimeMetadataDecoderImpl.PRESERVED_FLAG_MASK);
+        }
+    }
 }

substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/jni/access/JNIAccessibleElement.java renamed to substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/jni/access/PreservableJNIElement.java

@@ -24,21 +24,20 @@
  */
 package com.oracle.svm.core.jni.access;
 
-public abstract class JNIAccessibleElement {
-    private volatile boolean preserved;
+import org.graalvm.nativeimage.Platform;
+import org.graalvm.nativeimage.Platforms;
 
-    protected JNIAccessibleElement(boolean preserved) {
-        this.preserved = preserved;
-    }
+/**
+ * Represents a JNI element that can be included in the image by
+ * {@link com.oracle.svm.core.SubstrateOptions#Preserve}. Records whether it was preserved or
+ * actually registered in the image.
+ *
+ * @since 25.1
+ */
+public interface PreservableJNIElement {
 
-    public void reportReregistered(boolean reregisterPreserved) {
-        // State can only ever go from "preserved" to "not preserved".
-        if (!reregisterPreserved) {
-            this.preserved = false;
-        }
-    }
+    boolean isPreserved();
 
-    public boolean isPreserved() {
-        return preserved;
-    }
+    @Platforms(Platform.HOSTED_ONLY.class)
+    void reportReregistered(boolean updatedPreserved);
 }

substratevm/src/com.oracle.svm.hosted/src/com/oracle/svm/hosted/jni/JNIAccessFeature.java

@@ -475,7 +475,7 @@ public void addMethod(Executable method, boolean preserved, DuringAnalysisAccess
             if (!Modifier.isStatic(method.getModifiers()) && !Modifier.isAbstract(method.getModifiers())) {
                 nonvirtualVariantWrappers = createJavaCallVariantWrappers(access, callWrapperMethod.getSignature(), true, method);
             }
-            JNIAccessibleMethod jniMethod = new JNIAccessibleMethod(preserved, jniClass, method.getModifiers());
+            JNIAccessibleMethod jniMethod = new JNIAccessibleMethod(jniClass, method.getModifiers(), preserved);
             calledJavaMethods.add(new JNICallableJavaMethod(descriptor, jniMethod, targetMethod, callWrapperMethod, newObjectMethod, variantWrappers, nonvirtualVariantWrappers));
             return jniMethod;
         });
@@ -513,7 +513,7 @@ private void addField(Field reflField, boolean preserved, boolean writable, Duri
         }
         JNIAccessibleClass jniClass = addClass(reflField.getDeclaringClass(), preserved, access);
         AnalysisField field = access.getMetaAccess().lookupJavaField(reflField);
-        jniClass.addOrUpdateField(field.getName(), preserved, _ -> new JNIAccessibleField(preserved, jniClass, field.getJavaKind(), field.getModifiers()));
+        jniClass.addOrUpdateField(field.getName(), preserved, _ -> new JNIAccessibleField(jniClass, field.getJavaKind(), field.getModifiers(), preserved));
         field.registerAsRead("it is registered for as JNI accessed");
         if (writable) {
             field.registerAsWritten("it is registered as JNI writable");