Remove SubstrateVirtualThreads.

Author: peter-hofer

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

@@ -138,9 +138,6 @@ protected void onValueUpdate(EconomicMap<OptionKey<?>, Object> values, Boolean o
         }
     };
 
-    @Option(help = "Support continuations (without requiring a Project Loom JDK)") //
-    public static final HostedOptionKey<Boolean> SupportContinuations = new HostedOptionKey<>(false);
-
     public static final int ForceFallback = 10;
     public static final int Automatic = 5;
     public static final int NoFallback = 0;

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

@@ -28,9 +28,7 @@
 
 import com.oracle.svm.core.NeverInline;
 import com.oracle.svm.core.SubstrateOptions;
-import com.oracle.svm.core.Uninterruptible;
 import com.oracle.svm.core.annotate.Alias;
-import com.oracle.svm.core.annotate.AnnotateOriginal;
 import com.oracle.svm.core.annotate.Delete;
 import com.oracle.svm.core.annotate.InjectAccessors;
 import com.oracle.svm.core.annotate.RecomputeFieldValue;
@@ -52,10 +50,6 @@ public static String getSavedProperty(String name) {
         return SystemPropertiesSupport.singleton().getSavedProperties().get(name);
     }
 
-    @AnnotateOriginal
-    @Uninterruptible(reason = "Called from uninterruptible code.", mayBeInlined = true)
-    public static native Thread.State toThreadState(int threadStatus);
-
     @Substitute
     @NeverInline("Starting a stack walk in the caller frame")
     public static ClassLoader latestUserDefinedLoader0() {

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

@@ -32,7 +32,6 @@
 import org.graalvm.word.WordFactory;
 
 import com.oracle.svm.core.NeverInline;
-import com.oracle.svm.core.SubstrateOptions;
 import com.oracle.svm.core.heap.StoredContinuation;
 import com.oracle.svm.core.heap.StoredContinuationAccess;
 import com.oracle.svm.core.heap.VMOperationInfos;
@@ -42,15 +41,12 @@
 import com.oracle.svm.core.stack.StackOverflowCheck;
 import com.oracle.svm.core.util.VMError;
 
-/**
- * Foundation for continuation support via {@link SubstrateVirtualThread} or
- * {@linkplain Target_jdk_internal_vm_Continuation Project Loom}.
- */
+/** Foundation for {@linkplain Target_jdk_internal_vm_Continuation Project Loom} support. */
 @InternalVMMethod
 public final class Continuation {
     @Fold
     public static boolean isSupported() {
-        return SubstrateOptions.SupportContinuations.getValue() || LoomSupport.isEnabled();
+        return LoomSupport.isEnabled();
     }
 
     public static final int YIELDING = -2;
@@ -69,7 +65,6 @@ public static boolean isSupported() {
     /** While executing, frame pointer of initial frame of continuation, {@code null} otherwise. */
     private Pointer baseSP;
 
-    private boolean done;
     private int overflowCheckState;
 
     Continuation(Runnable target) {
@@ -167,7 +162,6 @@ private void enter2() {
         Pointer returnSP = sp;
         CodePointer returnIP = ip;
 
-        done = true;
         ip = WordFactory.nullPointer();
         sp = WordFactory.nullPointer();
         baseSP = WordFactory.nullPointer();
@@ -215,18 +209,14 @@ private Integer yield0() {
         throw VMError.shouldNotReachHereAtRuntime();
     }
 
-    public boolean isStarted() {
+    boolean isStarted() {
         return stored != null || ip.isNonNull();
     }
 
-    public boolean isEmpty() {
+    boolean isEmpty() {
         return stored == null;
     }
 
-    public boolean isDone() {
-        return done;
-    }
-
     private static final class TryPreemptOperation extends JavaVMOperation {
         int preemptStatus = FREEZE_OK;
 

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

@@ -36,8 +36,6 @@
 import com.oracle.svm.core.feature.InternalFeature;
 import com.oracle.svm.core.heap.StoredContinuation;
 import com.oracle.svm.core.heap.StoredContinuationAccess;
-import com.oracle.svm.core.option.SubstrateOptionsParser;
-import com.oracle.svm.core.util.UserError;
 import com.oracle.svm.core.util.VMError;
 import com.oracle.svm.util.ReflectionUtil;
 
@@ -78,22 +76,6 @@ public void afterRegistration(AfterRegistrationAccess access) {
             LoomVirtualThreads vt = new LoomVirtualThreads();
             ImageSingletons.add(VirtualThreads.class, vt);
             ImageSingletons.add(LoomVirtualThreads.class, vt); // for simpler check in LoomSupport
-        } else if (SubstrateOptions.SupportContinuations.getValue()) {
-            if (DeoptimizationSupport.enabled()) {
-                throw UserError.abort("Option %s is in use, but is not supported together with Truffle JIT compilation.",
-                                SubstrateOptionsParser.commandArgument(SubstrateOptions.SupportContinuations, "+"));
-            } else if (SubstrateOptions.useLLVMBackend()) {
-                throw UserError.abort("Option %s is in use, but is not supported together with the LLVM backend.",
-                                SubstrateOptionsParser.commandArgument(SubstrateOptions.SupportContinuations, "+"));
-            } else if (JavaVersionUtil.JAVA_SPEC == 17) {
-                ImageSingletons.add(VirtualThreads.class, new SubstrateVirtualThreads());
-            } else if (JavaVersionUtil.JAVA_SPEC >= firstLoomPreviewVersion && JavaVersionUtil.JAVA_SPEC <= lastLoomPreviewVersion) {
-                throw UserError.abort("Virtual threads on JDK %d are supported only with preview features enabled (--enable-preview). Using option %s is unnecessary.",
-                                JavaVersionUtil.JAVA_SPEC, SubstrateOptionsParser.commandArgument(SubstrateOptions.SupportContinuations, "+"));
-            } else {
-                throw UserError.abort("Option %s is in use, but is not supported on JDK %d.",
-                                SubstrateOptionsParser.commandArgument(SubstrateOptions.SupportContinuations, "+"), JavaVersionUtil.JAVA_SPEC);
-            }
         }
         finishedRegistration = true;
     }
@@ -129,6 +111,6 @@ public void beforeCompilation(BeforeCompilationAccess access) {
     }
 
     static void abortIfUnsupported() {
-        VMError.guarantee(Continuation.isSupported(), "Virtual thread internals are reachable but support is not available or active.");
+        VMError.guarantee(Continuation.isSupported(), "Virtual threads internals are reachable but support is not available or active.");
     }
 }