Park Darwin main thread in CFRunLoop for headed AWT/Swing to fix hang

substratevm/src/com.oracle.svm.core.posix/src/com/oracle/svm/core/posix/darwin/DarwinMainCFRunLoopSupportImpl.java

@@ -0,0 +1,127 @@
+/*
+ * Copyright (c) 2026, 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.posix.darwin;
+
+import static com.oracle.svm.core.posix.headers.darwin.CoreFoundation.CFRunLoopAddTimer;
+import static com.oracle.svm.core.posix.headers.darwin.CoreFoundation.CFRunLoopGetCurrent;
+import static com.oracle.svm.core.posix.headers.darwin.CoreFoundation.CFRunLoopRunInMode;
+import static com.oracle.svm.core.posix.headers.darwin.CoreFoundation.CFRunLoopTimerCreate;
+import static com.oracle.svm.core.posix.headers.darwin.CoreFoundation.CFRelease;
+import static com.oracle.svm.core.posix.headers.darwin.CoreFoundation.kCFAllocatorDefault;
+import static com.oracle.svm.core.posix.headers.darwin.CoreFoundation.kCFRunLoopDefaultMode;
+import static com.oracle.svm.core.posix.headers.darwin.CoreFoundation.kCFRunLoopRunFinished;
+
+import org.graalvm.nativeimage.Platform;
+import org.graalvm.nativeimage.Platforms;
+import org.graalvm.nativeimage.c.function.CEntryPoint;
+import org.graalvm.nativeimage.c.function.CEntryPointLiteral;
+import org.graalvm.nativeimage.c.type.VoidPointer;
+import org.graalvm.word.WordFactory;
+
+import com.oracle.svm.core.DarwinMainCFRunLoopSupport;
+import com.oracle.svm.core.SubstrateOptions;
+import com.oracle.svm.core.feature.InternalFeature;
+import com.oracle.svm.core.posix.headers.darwin.CoreFoundation.CFRunLoopTimerCallBack;
+import com.oracle.svm.core.posix.headers.darwin.CoreFoundation.CFRunLoopTimerRef;
+import com.oracle.svm.guest.staging.c.function.CEntryPointOptions;
+import com.oracle.svm.guest.staging.c.function.CEntryPointOptions.NoEpilogue;
+import com.oracle.svm.guest.staging.c.function.CEntryPointOptions.NoPrologue;
+import com.oracle.svm.shared.Uninterruptible;
+import com.oracle.svm.shared.feature.AutomaticallyRegisteredFeature;
+import com.oracle.svm.shared.singletons.traits.BuiltinTraits.AllAccess;
+import com.oracle.svm.shared.singletons.traits.BuiltinTraits.SingleLayer;
+import com.oracle.svm.shared.singletons.traits.SingletonLayeredInstallationKind.InitialLayerOnly;
+import com.oracle.svm.shared.singletons.traits.SingletonTraits;
+import com.oracle.svm.shared.util.VMError;
+
+import org.graalvm.nativeimage.ImageSingletons;
+
+/**
+ * Parks the process main thread in a CFRunLoop, matching OpenJDK libjli /
+ * {@code sdk/.../launcher.cc} {@code ParkEventLoop}.
+ *
+ * @see <a href="https://github.com/oracle/graal/issues/13994">oracle/graal#13994</a>
+ */
+@Platforms(Platform.DARWIN.class)
+@SingletonTraits(access = AllAccess.class, layeredCallbacks = SingleLayer.class, layeredInstallationKind = InitialLayerOnly.class)
+public final class DarwinMainCFRunLoopSupportImpl implements DarwinMainCFRunLoopSupport {
+
+    /**
+     * Far-future fire date so the timer exists only as a run-loop source (libjli pattern).
+     */
+    private static final double FAR_FUTURE = 1.0e20;
+
+    private static final CEntryPointLiteral<CFRunLoopTimerCallBack> DUMMY_TIMER_CALLBACK = CEntryPointLiteral.create(DarwinMainCFRunLoopSupportImpl.class, "dummyTimer",
+                    CFRunLoopTimerRef.class, VoidPointer.class);
+
+    @Override
+    @Uninterruptible(reason = "Called while the launcher thread is detached from the isolate.")
+    public void parkEventLoop() {
+        /*
+         * See OpenJDK java_md_macosx.m ParkEventLoop and Graal launcher.cc ParkEventLoop: the run
+         * loop needs at least one source; 1e20 is far into the future.
+         */
+        CFRunLoopTimerRef timer = CFRunLoopTimerCreate(kCFAllocatorDefault(), FAR_FUTURE, 0.0, 0, 0, DUMMY_TIMER_CALLBACK.getFunctionPointer(), WordFactory.nullPointer());
+        CFRunLoopAddTimer(CFRunLoopGetCurrent(), timer, kCFRunLoopDefaultMode());
+        CFRelease(timer);
+
+        int result;
+        do {
+            result = CFRunLoopRunInMode(kCFRunLoopDefaultMode(), FAR_FUTURE, false);
+        } while (result != kCFRunLoopRunFinished());
+    }
+
+    @SuppressWarnings("unused")
+    @Uninterruptible(reason = "Called from CFRunLoop.")
+    @CEntryPoint(include = DarwinParkMainInCFRunLoopEnabled.class)
+    @CEntryPointOptions(prologue = NoPrologue.class, epilogue = NoEpilogue.class)
+    static void dummyTimer(CFRunLoopTimerRef timer, VoidPointer info) {
+        /* Intentionally empty — timer exists only to keep the run loop alive. */
+    }
+
+    private static final class DarwinParkMainInCFRunLoopEnabled implements java.util.function.BooleanSupplier {
+        @Override
+        public boolean getAsBoolean() {
+            return SubstrateOptions.DarwinParkMainInCFRunLoop.getValue();
+        }
+    }
+}
+
+@Platforms(Platform.DARWIN.class)
+@AutomaticallyRegisteredFeature
+class DarwinMainCFRunLoopFeature implements InternalFeature {
+    @Override
+    public boolean isInConfiguration(IsInConfigurationAccess access) {
+        return SubstrateOptions.DarwinParkMainInCFRunLoop.getValue();
+    }
+
+    @Override
+    public void afterRegistration(AfterRegistrationAccess access) {
+        if (!Platform.includedIn(Platform.DARWIN.class)) {
+            throw VMError.shouldNotReachHere("-H:+DarwinParkMainInCFRunLoop is only supported on Darwin");
+        }
+        ImageSingletons.add(DarwinMainCFRunLoopSupport.class, new DarwinMainCFRunLoopSupportImpl());
+    }
+}

substratevm/src/com.oracle.svm.core.posix/src/com/oracle/svm/core/posix/headers/darwin/CoreFoundation.java

@@ -0,0 +1,93 @@
+/*
+ * Copyright (c) 2026, 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.posix.headers.darwin;
+
+import org.graalvm.nativeimage.c.CContext;
+import org.graalvm.nativeimage.c.constant.CConstant;
+import org.graalvm.nativeimage.c.function.CFunction;
+import org.graalvm.nativeimage.c.function.CFunction.Transition;
+import org.graalvm.nativeimage.c.function.CFunctionPointer;
+import org.graalvm.nativeimage.c.function.CLibrary;
+import org.graalvm.nativeimage.c.function.InvokeCFunctionPointer;
+import org.graalvm.nativeimage.c.type.VoidPointer;
+import org.graalvm.word.PointerBase;
+
+import com.oracle.svm.core.posix.headers.darwin.CoreFoundationDirectives;
+
+// Checkstyle: stop
+
+/**
+ * Minimal CoreFoundation bindings for parking the Darwin main thread in a CFRunLoop, matching the
+ * pattern used by OpenJDK libjli and {@code org.graalvm.launcher.native} {@code ParkEventLoop}.
+ */
+@CContext(CoreFoundationDirectives.class)
+@CLibrary("-framework CoreFoundation")
+public class CoreFoundation {
+
+    public interface CFTypeRef extends PointerBase {
+    }
+
+    public interface CFAllocatorRef extends CFTypeRef {
+    }
+
+    public interface CFRunLoopRef extends CFTypeRef {
+    }
+
+    public interface CFRunLoopTimerRef extends CFTypeRef {
+    }
+
+    public interface CFStringRef extends CFTypeRef {
+    }
+
+    public interface CFRunLoopTimerCallBack extends CFunctionPointer {
+        @InvokeCFunctionPointer
+        void invoke(CFRunLoopTimerRef timer, VoidPointer info);
+    }
+
+    @CConstant
+    public static native CFAllocatorRef kCFAllocatorDefault();
+
+    @CConstant
+    public static native CFStringRef kCFRunLoopDefaultMode();
+
+    @CConstant
+    public static native int kCFRunLoopRunFinished();
+
+    @CFunction(transition = Transition.NO_TRANSITION)
+    public static native CFRunLoopRef CFRunLoopGetCurrent();
+
+    @CFunction(transition = Transition.NO_TRANSITION)
+    public static native CFRunLoopTimerRef CFRunLoopTimerCreate(CFAllocatorRef allocator, double fireDate, double interval, long flags, long order,
+                    CFRunLoopTimerCallBack callout, VoidPointer context);
+
+    @CFunction(transition = Transition.NO_TRANSITION)
+    public static native void CFRunLoopAddTimer(CFRunLoopRef rl, CFRunLoopTimerRef timer, CFStringRef mode);
+
+    @CFunction(transition = Transition.NO_TRANSITION)
+    public static native int CFRunLoopRunInMode(CFStringRef mode, double seconds, boolean returnAfterSourceHandled);
+
+    @CFunction(transition = Transition.NO_TRANSITION)
+    public static native void CFRelease(CFTypeRef cf);
+}

substratevm/src/com.oracle.svm.core.posix/src/com/oracle/svm/core/posix/headers/darwin/CoreFoundationDirectives.java

@@ -0,0 +1,55 @@
+/*
+ * Copyright (c) 2026, 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.posix.headers.darwin;
+
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+
+import org.graalvm.nativeimage.Platform;
+import org.graalvm.nativeimage.c.CContext;
+
+public class CoreFoundationDirectives implements CContext.Directives {
+    @Override
+    public boolean isInConfiguration() {
+        return Platform.includedIn(Platform.DARWIN.class);
+    }
+
+    @Override
+    public List<String> getHeaderFiles() {
+        return Collections.singletonList("<CoreFoundation/CoreFoundation.h>");
+    }
+
+    @Override
+    public List<String> getOptions() {
+        /* Info-query linking must resolve CF constants such as kCFAllocatorDefault. */
+        return Arrays.asList("-framework", "CoreFoundation");
+    }
+
+    @Override
+    public List<String> getLibraries() {
+        return Collections.singletonList("-framework CoreFoundation");
+    }
+}

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

@@ -0,0 +1,44 @@
+/*
+ * Copyright (c) 2026, 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 com.oracle.svm.shared.Uninterruptible;
+
+/**
+ * Parks the Darwin process main thread in a CoreFoundation run loop so AppKit/Metal work posted to
+ * the main thread can run while Java executes on a dedicated platform thread.
+ * <p>
+ * Mirrors OpenJDK {@code libjli} / Graal {@code launcher.cc} {@code ParkEventLoop}.
+ */
+public interface DarwinMainCFRunLoopSupport {
+
+    /**
+     * Blocks the current (process main) thread in {@code CFRunLoopRunInMode}. Under normal
+     * shutdown the Java main runner calls {@code LibC.exit} after waiting for non-daemon threads,
+     * so this method does not return.
+     */
+    @Uninterruptible(reason = "Called while the launcher thread is detached from the isolate.")
+    void parkEventLoop();
+}