Further review feedback.

Author: christianhaeubl

substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/Containers.java

@@ -26,7 +26,7 @@
 
 import static com.oracle.svm.core.Containers.Options.PreferContainerQuotaForCPUCount;
 import static com.oracle.svm.core.Containers.Options.UseContainerSupport;
-import static com.oracle.svm.core.option.RuntimeOptionKey.RelevantForCompilationIsolates;
+import static com.oracle.svm.core.option.RuntimeOptionKey.RuntimeOptionKeyFlag.RelevantForCompilationIsolates;
 
 import org.graalvm.compiler.options.Option;
 import org.graalvm.compiler.serviceprovider.JavaVersionUtil;

substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/SubstrateDiagnostics.java

@@ -24,9 +24,10 @@
  */
 package com.oracle.svm.core;
 
+import static com.oracle.svm.core.option.RuntimeOptionKey.RuntimeOptionKeyFlag.RelevantForCompilationIsolates;
+
 import java.util.Arrays;
 
-import com.oracle.svm.core.option.RuntimeOptionKey;
 import org.graalvm.collections.EconomicMap;
 import org.graalvm.compiler.api.replacements.Fold;
 import org.graalvm.compiler.core.common.NumUtil;
@@ -69,6 +70,7 @@
 import com.oracle.svm.core.jdk.UninterruptibleUtils.AtomicWord;
 import com.oracle.svm.core.locks.VMLockSupport;
 import com.oracle.svm.core.log.Log;
+import com.oracle.svm.core.option.RuntimeOptionKey;
 import com.oracle.svm.core.stack.JavaFrameAnchor;
 import com.oracle.svm.core.stack.JavaFrameAnchors;
 import com.oracle.svm.core.stack.JavaStackWalker;
@@ -86,8 +88,6 @@
 import com.oracle.svm.core.threadlocal.VMThreadLocalInfos;
 import com.oracle.svm.core.util.Counter;
 
-import static com.oracle.svm.core.option.RuntimeOptionKey.RelevantForCompilationIsolates;
-
 public class SubstrateDiagnostics {
     private static final FastThreadLocalBytes<CCharPointer> threadOnlyAttachedForCrashHandler = FastThreadLocalFactory.createBytes(() -> 1, "SubstrateDiagnostics.threadOnlyAttachedForCrashHandler");
     private static volatile boolean loopOnFatalError;

substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/SubstrateOptions.java

@@ -24,7 +24,7 @@
  */
 package com.oracle.svm.core;
 
-import static com.oracle.svm.core.option.RuntimeOptionKey.RelevantForCompilationIsolates;
+import static com.oracle.svm.core.option.RuntimeOptionKey.RuntimeOptionKeyFlag.RelevantForCompilationIsolates;
 import static org.graalvm.compiler.core.common.GraalOptions.TrackNodeSourcePosition;
 import static org.graalvm.compiler.core.common.SpectrePHTMitigations.None;
 import static org.graalvm.compiler.core.common.SpectrePHTMitigations.Options.SpectrePHTBarriers;
@@ -36,8 +36,6 @@
 import java.nio.file.Path;
 import java.nio.file.Paths;
 
-import com.oracle.svm.core.heap.ReferenceHandler;
-import com.oracle.svm.core.thread.VMOperationControl;
 import org.graalvm.collections.EconomicMap;
 import org.graalvm.collections.UnmodifiableEconomicMap;
 import org.graalvm.compiler.api.replacements.Fold;
@@ -53,12 +51,14 @@
 import org.graalvm.nativeimage.ImageSingletons;
 
 import com.oracle.svm.core.deopt.DeoptimizationSupport;
+import com.oracle.svm.core.heap.ReferenceHandler;
 import com.oracle.svm.core.option.APIOption;
 import com.oracle.svm.core.option.APIOptionGroup;
 import com.oracle.svm.core.option.HostedOptionKey;
 import com.oracle.svm.core.option.ImmutableRuntimeOptionKey;
 import com.oracle.svm.core.option.LocatableMultiOptionValue;
 import com.oracle.svm.core.option.RuntimeOptionKey;
+import com.oracle.svm.core.thread.VMOperationControl;
 import com.oracle.svm.core.util.UserError;
 
 public class SubstrateOptions {

substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/code/RuntimeCodeCache.java

@@ -24,7 +24,7 @@
  */
 package com.oracle.svm.core.code;
 
-import static com.oracle.svm.core.option.RuntimeOptionKey.RelevantForCompilationIsolates;
+import static com.oracle.svm.core.option.RuntimeOptionKey.RuntimeOptionKeyFlag.RelevantForCompilationIsolates;
 import static com.oracle.svm.core.snippets.KnownIntrinsics.readCallerStackPointer;
 
 import org.graalvm.compiler.options.Option;

substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/option/GCRuntimeOptionKey.java

@@ -31,8 +31,8 @@
  * Notifies the {@link Heap} implementation after the value of the option has changed.
  */
 public class GCRuntimeOptionKey<T> extends RuntimeOptionKey<T> {
-    public GCRuntimeOptionKey(T defaultValue) {
-        super(defaultValue);
+    public GCRuntimeOptionKey(T defaultValue, RuntimeOptionKeyFlag... flags) {
+        super(defaultValue, flags);
     }
 
     @Override

substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/option/ImmutableGCRuntimeOptionKey.java

@@ -32,8 +32,8 @@
  * option was set.
  */
 public class ImmutableGCRuntimeOptionKey<T> extends ImmutableRuntimeOptionKey<T> {
-    public ImmutableGCRuntimeOptionKey(T defaultValue) {
-        super(defaultValue);
+    public ImmutableGCRuntimeOptionKey(T defaultValue, RuntimeOptionKeyFlag... flags) {
+        super(defaultValue, flags);
     }
 
     @Override

substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/option/ImmutableRuntimeOptionKey.java

@@ -37,12 +37,8 @@
  * A runtime option that can only be modified as long as the VM is not fully initialized yet.
  */
 public class ImmutableRuntimeOptionKey<T> extends RuntimeOptionKey<T> {
-    public ImmutableRuntimeOptionKey(T defaultValue) {
-        super(defaultValue);
-    }
-
-    public ImmutableRuntimeOptionKey(T defaultValue, boolean isRelevantForCompilationIsolate) {
-        super(defaultValue, isRelevantForCompilationIsolate);
+    public ImmutableRuntimeOptionKey(T defaultValue, RuntimeOptionKeyFlag... flags) {
+        super(defaultValue, flags);
     }
 
     @Override

substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/option/RuntimeOptionKey.java

@@ -34,17 +34,11 @@
  * @see com.oracle.svm.core.option
  */
 public class RuntimeOptionKey<T> extends OptionKey<T> {
-    public static final boolean RelevantForCompilationIsolates = true;
+    private final int flags;
 
-    private final boolean copyToCompilationIsolate;
-
-    public RuntimeOptionKey(T defaultValue) {
-        this(defaultValue, false);
-    }
-
-    public RuntimeOptionKey(T defaultValue, boolean isRelevantForCompilationIsolate) {
+    public RuntimeOptionKey(T defaultValue, RuntimeOptionKeyFlag... flags) {
         super(defaultValue);
-        this.copyToCompilationIsolate = isRelevantForCompilationIsolate;
+        this.flags = computeFlags(flags);
     }
 
     /**
@@ -63,11 +57,24 @@ public boolean hasBeenSet() {
     }
 
     public boolean shouldCopyToCompilationIsolate() {
-        return copyToCompilationIsolate;
+        return (flags & RuntimeOptionKeyFlag.RelevantForCompilationIsolates.ordinal()) != 0;
     }
 
     @Fold
     public T getHostedValue() {
         return getValue(RuntimeOptionValues.singleton());
     }
+
+    private static int computeFlags(RuntimeOptionKeyFlag[] flags) {
+        int result = 0;
+        for (RuntimeOptionKeyFlag flag : flags) {
+            assert flag.ordinal() <= Integer.SIZE - 1;
+            result |= 1 << flag.ordinal();
+        }
+        return result;
+    }
+
+    public enum RuntimeOptionKeyFlag {
+        RelevantForCompilationIsolates
+    }
 }

substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/thread/Safepoint.java

@@ -24,6 +24,8 @@
  */
 package com.oracle.svm.core.thread;
 
+import static com.oracle.svm.core.option.RuntimeOptionKey.RuntimeOptionKeyFlag.RelevantForCompilationIsolates;
+
 import java.util.concurrent.atomic.AtomicInteger;
 
 import org.graalvm.compiler.api.replacements.Fold;
@@ -77,8 +79,6 @@
 import com.oracle.svm.core.util.TimeUtils;
 import com.oracle.svm.core.util.VMError;
 
-import static com.oracle.svm.core.option.RuntimeOptionKey.RelevantForCompilationIsolates;
-
 /**
  * Support for initiating safepoints, which are a global state in which all threads are paused so
  * that an invasive operation (such as garbage collection) can execute without interferences.

substratevm/src/com.oracle.svm.graal/src/com/oracle/svm/graal/SubstrateGraalUtils.java

@@ -24,7 +24,7 @@
  */
 package com.oracle.svm.graal;
 
-import static com.oracle.svm.core.option.RuntimeOptionKey.RelevantForCompilationIsolates;
+import static com.oracle.svm.core.option.RuntimeOptionKey.RuntimeOptionKeyFlag.RelevantForCompilationIsolates;
 import static com.oracle.svm.core.util.VMError.shouldNotReachHere;
 
 import java.io.PrintStream;