[GR-54786] Cross-isolate exception dispatch for isolated compilation.

PullRequest: graal/19884

Author: peter-hofer

substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/c/function/CEntryPointOptions.java

@@ -30,7 +30,6 @@
 import java.lang.annotation.Target;
 import java.util.function.Function;
 
-import jdk.graal.compiler.word.Word;
 import org.graalvm.nativeimage.c.function.CEntryPoint;
 import org.graalvm.word.PointerBase;
 
@@ -39,6 +38,8 @@
 import com.oracle.svm.core.c.function.CEntryPointSetup.EnterPrologue;
 import com.oracle.svm.core.c.function.CEntryPointSetup.LeaveEpilogue;
 
+import jdk.graal.compiler.word.Word;
+
 @Retention(RetentionPolicy.RUNTIME)
 @Target(ElementType.METHOD)
 public @interface CEntryPointOptions {
@@ -151,14 +152,30 @@ final class NoEpilogue implements Epilogue {
     }
 
     /**
-     * Specifies a class with epilogue code that is executed when the entry point method returns to
-     * C in order to leave the execution context. See {@link CEntryPointSetup} for commonly used
-     * epilogues.
+     * Specifies a class with epilogue code that is executed just before the entry point method
+     * returns to C in order to leave the execution context. See {@link CEntryPointSetup} for
+     * commonly used epilogues.
      * <p>
      * The given class must have exactly one static {@link Uninterruptible} method with no
      * parameters. Within the epilogue method, {@link CEntryPointActions} can be used to leave the
      * execution context.
      */
     Class<? extends Epilogue> epilogue() default LeaveEpilogue.class;
 
+    /** Marker interface for {@linkplain #callerEpilogue caller epilogue} classes. */
+    interface CallerEpilogue {
+    }
+
+    /** Placeholder class for {@link #callerEpilogue()} to omit an epilogue at call sites. */
+    final class NoCallerEpilogue implements CallerEpilogue {
+    }
+
+    /**
+     * Specifies a class with epilogue code that is executed by a Java <em>caller</em> of the entry
+     * point after the call has returned, in the caller's isolate. This code is injected only at
+     * sites of <em>direct Java calls</em> to the {@link CEntryPoint}-annotated method, but not
+     * where it is called by its address or symbol, for example from C code. The specified class
+     * must have exactly one static method with no parameters.
+     */
+    Class<? extends CallerEpilogue> callerEpilogue() default NoCallerEpilogue.class;
 }

substratevm/src/com.oracle.svm.graal/src/com/oracle/svm/graal/isolated/IsolateAwareConstantReflectionProvider.java

@@ -26,12 +26,11 @@
 
 import java.lang.reflect.Array;
 
-import jdk.graal.compiler.core.common.CompressEncoding;
-import jdk.graal.compiler.word.Word;
 import org.graalvm.nativeimage.StackValue;
 import org.graalvm.nativeimage.c.function.CEntryPoint;
 
 import com.oracle.svm.core.SubstrateOptions;
+import com.oracle.svm.core.c.function.CEntryPointOptions;
 import com.oracle.svm.core.graal.meta.SubstrateMemoryAccessProvider;
 import com.oracle.svm.core.hub.DynamicHub;
 import com.oracle.svm.core.meta.SubstrateObjectConstant;
@@ -40,6 +39,8 @@
 import com.oracle.svm.graal.meta.SubstrateMemoryAccessProviderImpl;
 import com.oracle.svm.graal.meta.SubstrateMetaAccess;
 
+import jdk.graal.compiler.core.common.CompressEncoding;
+import jdk.graal.compiler.word.Word;
 import jdk.vm.ci.meta.Constant;
 import jdk.vm.ci.meta.JavaConstant;
 import jdk.vm.ci.meta.JavaKind;
@@ -84,7 +85,8 @@ private static JavaConstant read(JavaKind kind, Constant base, long displacement
             return ConstantDataConverter.toCompiler(resultData);
         }
 
-        @CEntryPoint(include = CEntryPoint.NotIncludedAutomatically.class, publishAs = CEntryPoint.Publish.NotPublished)
+        @CEntryPoint(exceptionHandler = IsolatedCompileClient.VoidExceptionHandler.class, include = CEntryPoint.NotIncludedAutomatically.class, publishAs = CEntryPoint.Publish.NotPublished)
+        @CEntryPointOptions(callerEpilogue = IsolatedCompileClient.ExceptionRethrowCallerEpilogue.class)
         private static void read0(@SuppressWarnings("unused") ClientIsolateThread client, char kindChar, ConstantData baseData, long displacement,
                         int primitiveBits, long compressBase, int compressShift, ConstantData resultData) {
             JavaConstant base = ConstantDataConverter.toClient(baseData);
@@ -129,7 +131,8 @@ public Integer readArrayLength(JavaConstant array) {
         return Array.getLength(arrayObj);
     }
 
-    @CEntryPoint(include = CEntryPoint.NotIncludedAutomatically.class, publishAs = CEntryPoint.Publish.NotPublished)
+    @CEntryPoint(exceptionHandler = IsolatedCompileClient.IntExceptionHandler.class, include = CEntryPoint.NotIncludedAutomatically.class, publishAs = CEntryPoint.Publish.NotPublished)
+    @CEntryPointOptions(callerEpilogue = IsolatedCompileClient.ExceptionRethrowCallerEpilogue.class)
     private static int readArrayLength0(@SuppressWarnings("unused") ClientIsolateThread client, ClientHandle<?> arrayHandle) {
         Object array = IsolatedCompileClient.get().unhand(arrayHandle);
         if (!array.getClass().isArray()) {
@@ -153,7 +156,8 @@ public JavaConstant readArrayElement(JavaConstant array, int index) {
         return ConstantDataConverter.toCompiler(resultData);
     }
 
-    @CEntryPoint(include = CEntryPoint.NotIncludedAutomatically.class, publishAs = CEntryPoint.Publish.NotPublished)
+    @CEntryPoint(exceptionHandler = IsolatedCompileClient.VoidExceptionHandler.class, include = CEntryPoint.NotIncludedAutomatically.class, publishAs = CEntryPoint.Publish.NotPublished)
+    @CEntryPointOptions(callerEpilogue = IsolatedCompileClient.ExceptionRethrowCallerEpilogue.class)
     private static void readArrayElement0(@SuppressWarnings("unused") ClientIsolateThread client, ConstantData arrayData, int index, ConstantData resultData) {
         JavaConstant array = ConstantDataConverter.toClient(arrayData);
         Object a = SubstrateObjectConstant.asObject(array);
@@ -181,14 +185,16 @@ public JavaConstant readFieldValue(ResolvedJavaField field, JavaConstant receive
         return ConstantDataConverter.toCompiler(resultData);
     }
 
-    @CEntryPoint(include = CEntryPoint.NotIncludedAutomatically.class, publishAs = CEntryPoint.Publish.NotPublished)
+    @CEntryPoint(exceptionHandler = IsolatedCompileClient.VoidExceptionHandler.class, include = CEntryPoint.NotIncludedAutomatically.class, publishAs = CEntryPoint.Publish.NotPublished)
+    @CEntryPointOptions(callerEpilogue = IsolatedCompileClient.ExceptionRethrowCallerEpilogue.class)
     private static void readFieldValue0(@SuppressWarnings("unused") ClientIsolateThread client, ImageHeapRef<SubstrateField> fieldRef, ConstantData receiverData, ConstantData resultData) {
         JavaConstant receiver = ConstantDataConverter.toClient(receiverData);
         Constant result = readFieldValue(ImageHeapObjects.deref(fieldRef), receiver);
         ConstantDataConverter.fromClient(result, resultData);
     }
 
-    @CEntryPoint(include = CEntryPoint.NotIncludedAutomatically.class, publishAs = CEntryPoint.Publish.NotPublished)
+    @CEntryPoint(exceptionHandler = IsolatedCompileClient.VoidExceptionHandler.class, include = CEntryPoint.NotIncludedAutomatically.class, publishAs = CEntryPoint.Publish.NotPublished)
+    @CEntryPointOptions(callerEpilogue = IsolatedCompileClient.ExceptionRethrowCallerEpilogue.class)
     private static void boxPrimitive0(@SuppressWarnings("unused") ClientIsolateThread client, ConstantData primitiveData, ConstantData resultData) {
         JavaConstant primitive = ConstantDataConverter.toClient(primitiveData);
         Constant result = SubstrateObjectConstant.forObject(primitive.asBoxedPrimitive());
@@ -208,7 +214,8 @@ public JavaConstant unboxPrimitive(JavaConstant boxed) {
         return super.unboxPrimitive(boxed);
     }
 
-    @CEntryPoint(include = CEntryPoint.NotIncludedAutomatically.class, publishAs = CEntryPoint.Publish.NotPublished)
+    @CEntryPoint(exceptionHandler = IsolatedCompileClient.VoidExceptionHandler.class, include = CEntryPoint.NotIncludedAutomatically.class, publishAs = CEntryPoint.Publish.NotPublished)
+    @CEntryPointOptions(callerEpilogue = IsolatedCompileClient.ExceptionRethrowCallerEpilogue.class)
     private static void unboxPrimitive0(@SuppressWarnings("unused") ClientIsolateThread client, ConstantData boxedData, ConstantData resultData) {
         Constant boxed = ConstantDataConverter.toClient(boxedData);
         Constant result = JavaConstant.forBoxedPrimitive(SubstrateObjectConstant.asObject(boxed));
@@ -232,7 +239,8 @@ public ResolvedJavaType asJavaType(Constant hub) {
         return super.asJavaType(resolved);
     }
 
-    @CEntryPoint(include = CEntryPoint.NotIncludedAutomatically.class, publishAs = CEntryPoint.Publish.NotPublished)
+    @CEntryPoint(exceptionHandler = IsolatedCompileClient.WordExceptionHandler.class, include = CEntryPoint.NotIncludedAutomatically.class, publishAs = CEntryPoint.Publish.NotPublished)
+    @CEntryPointOptions(callerEpilogue = IsolatedCompileClient.ExceptionRethrowCallerEpilogue.class)
     private static ImageHeapRef<DynamicHub> getHubConstantAsImageHeapRef(@SuppressWarnings("unused") ClientIsolateThread client, ConstantData hubData) {
         JavaConstant hub = ConstantDataConverter.toClient(hubData);
         Object target = SubstrateObjectConstant.asObject(hub);
@@ -260,7 +268,8 @@ public int getImageHeapOffset(JavaConstant constant) {
         return super.getImageHeapOffset(constant);
     }
 
-    @CEntryPoint(include = CEntryPoint.NotIncludedAutomatically.class, publishAs = CEntryPoint.Publish.NotPublished)
+    @CEntryPoint(exceptionHandler = IsolatedCompileClient.IntExceptionHandler.class, include = CEntryPoint.NotIncludedAutomatically.class, publishAs = CEntryPoint.Publish.NotPublished)
+    @CEntryPointOptions(callerEpilogue = IsolatedCompileClient.ExceptionRethrowCallerEpilogue.class)
     private static int getImageHeapOffset0(@SuppressWarnings("unused") ClientIsolateThread client, ConstantData constantData) {
         Constant constant = ConstantDataConverter.toClient(constantData);
         return getImageHeapOffsetInternal((SubstrateObjectConstant) constant);

substratevm/src/com.oracle.svm.graal/src/com/oracle/svm/graal/isolated/IsolateAwareObjectConstantEqualityFeature.java

@@ -28,6 +28,7 @@
 import org.graalvm.nativeimage.c.function.CEntryPoint;
 
 import com.oracle.svm.core.SubstrateOptions;
+import com.oracle.svm.core.c.function.CEntryPointOptions;
 import com.oracle.svm.core.feature.AutomaticallyRegisteredFeature;
 import com.oracle.svm.core.feature.InternalFeature;
 import com.oracle.svm.core.graal.RuntimeCompilation;
@@ -65,12 +66,14 @@ private static boolean compareIsolatedConstant(IsolatedObjectConstant a, Constan
         throw VMError.shouldNotReachHere("Unknown object constant: " + b);
     }
 
-    @CEntryPoint(include = CEntryPoint.NotIncludedAutomatically.class, publishAs = CEntryPoint.Publish.NotPublished)
+    @CEntryPoint(exceptionHandler = IsolatedCompileClient.BooleanExceptionHandler.class, include = CEntryPoint.NotIncludedAutomatically.class, publishAs = CEntryPoint.Publish.NotPublished)
+    @CEntryPointOptions(callerEpilogue = IsolatedCompileClient.ExceptionRethrowCallerEpilogue.class)
     static boolean isolatedConstantHandleTargetsEqual(@SuppressWarnings("unused") ClientIsolateThread client, ClientHandle<?> x, ClientHandle<?> y) {
         return IsolatedCompileClient.get().unhand(x) == IsolatedCompileClient.get().unhand(y);
     }
 
-    @CEntryPoint(include = CEntryPoint.NotIncludedAutomatically.class, publishAs = CEntryPoint.Publish.NotPublished)
+    @CEntryPoint(exceptionHandler = IsolatedCompileClient.BooleanExceptionHandler.class, include = CEntryPoint.NotIncludedAutomatically.class, publishAs = CEntryPoint.Publish.NotPublished)
+    @CEntryPointOptions(callerEpilogue = IsolatedCompileClient.ExceptionRethrowCallerEpilogue.class)
     private static boolean isolatedHandleTargetEqualImageObject(@SuppressWarnings("unused") ClientIsolateThread client, ClientHandle<?> x, ImageHeapRef<?> y) {
         return IsolatedCompileClient.get().unhand(x) == ImageHeapObjects.deref(y);
     }

substratevm/src/com.oracle.svm.graal/src/com/oracle/svm/graal/isolated/IsolatedCompilationExceptionDispatch.java

@@ -0,0 +1,148 @@
+/*
+ * 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.graal.isolated;
+
+import java.io.ByteArrayOutputStream;
+import java.io.PrintWriter;
+
+import org.graalvm.nativeimage.IsolateThread;
+import org.graalvm.nativeimage.c.function.CEntryPoint;
+import org.graalvm.nativeimage.c.type.CCharPointer;
+import org.graalvm.nativeimage.c.type.CTypeConversion;
+
+import com.oracle.svm.core.NeverInline;
+import com.oracle.svm.core.Uninterruptible;
+import com.oracle.svm.core.c.function.CEntryPointOptions;
+import com.oracle.svm.core.threadlocal.FastThreadLocalFactory;
+import com.oracle.svm.core.threadlocal.FastThreadLocalObject;
+import com.oracle.svm.hosted.code.CEntryPointCallStubMethod;
+import com.oracle.svm.hosted.code.CEntryPointJavaCallStubMethod;
+
+import jdk.graal.compiler.core.common.GraalBailoutException;
+
+/**
+ * Mechanism for dispatching exceptions across isolates with isolated compilation.
+ * <p>
+ * It relies on entry points having a {@link CEntryPoint#exceptionHandler} that invokes
+ * {@link #handleException}, which then calls into the other isolate (the entry point's caller
+ * isolate) to record that an exception has occurred. The entry point must further have a
+ * {@link CEntryPointOptions#callerEpilogue()} which executes in the caller isolate after the
+ * (original) call has returned and calls {@link #throwPendingException} to check whether an
+ * exception has been recorded, and if so, throw it. When no exception occurs, this comes at almost
+ * no extra cost.
+ * <p>
+ * Because objects cannot transcend isolate boundaries, exceptions are "rethrown" using a generic
+ * exception type with most information preserved in string form in their message.
+ */
+public abstract class IsolatedCompilationExceptionDispatch {
+    private static final RuntimeException EXCEPTION_WITHOUT_MESSAGE = new GraalBailoutException("[no details because exception allocation failed]");
+
+    /**
+     * An exception to be thrown in the current isolate as a result of it calling another isolate
+     * during which an exception has been caught.
+     */
+    private static final FastThreadLocalObject<RuntimeException> pendingException = FastThreadLocalFactory.createObject(RuntimeException.class,
+                    "IsolatedCompilationExceptionDispatch.pendingException");
+
+    protected static void throwPendingException() {
+        RuntimeException pending = pendingException.get();
+        if (pending != null) {
+            pendingException.set(null);
+            throw pending;
+        }
+    }
+
+    /** Provides the isolate to which an exception in the current isolate should be dispatched. */
+    @Uninterruptible(reason = "Called from uninterruptible code.", mayBeInlined = true)
+    protected abstract IsolateThread getOtherIsolate();
+
+    /**
+     * Dispatches an exception that was caught in an entry point to the isolate which called that
+     * entry point.
+     * <p>
+     * Note that the caller isolate cannot have called from uninterruptible code because
+     * {@link CEntryPointJavaCallStubMethod} does thread state transitions that require a safepoint
+     * check, so this method calling it back to dispatch the exception in interruptible code is
+     * considered acceptable.
+     * <p>
+     * Our (callee) entry point might intend to execute only uninterruptible code save for this
+     * exception handler, but as of writing this, isolated compilation nowhere requires relying on
+     * that and {@link CEntryPointCallStubMethod} also does state transitions and safepoint checks.
+     * <p>
+     * Also note that an exception's stack trace contains all its isolate's frames up until the last
+     * entry frame, but not another isolate's frames in between. When an exception is propagated
+     * through several entry points, this can make the output look confusing at first, but it is not
+     * too difficult to make sense of it.
+     */
+    @Uninterruptible(reason = "Called in exception handler.", calleeMustBe = false)
+    protected final int handleException(Throwable t) {
+        boolean done;
+        try {
+            done = dispatchExceptionToOtherIsolate(t);
+        } catch (Throwable another) {
+            done = false;
+        }
+        if (!done) {
+            // Being uninterruptible, this should never fail:
+            dispatchExceptionWithoutMessage(getOtherIsolate());
+        }
+        return 0;
+    }
+
+    @NeverInline("Ensure that an exception thrown from this method can always be caught.")
+    private boolean dispatchExceptionToOtherIsolate(Throwable t) {
+        ByteArrayOutputStream os = new ByteArrayOutputStream();
+        try (PrintWriter pw = new PrintWriter(os)) {
+            pw.print("{ ");
+            t.printStackTrace(pw); // trailing newline
+            pw.print("}");
+        }
+        try (CTypeConversion.CCharPointerHolder cstr = CTypeConversion.toCString(os.toString())) {
+            return dispatchException(getOtherIsolate(), cstr.get());
+        }
+    }
+
+    @CEntryPoint(exceptionHandler = ReturnFalseExceptionHandler.class, include = CEntryPoint.NotIncludedAutomatically.class, publishAs = CEntryPoint.Publish.NotPublished)
+    private static boolean dispatchException(@SuppressWarnings("unused") IsolateThread other, CCharPointer cstr) {
+        String message = CTypeConversion.toJavaString(cstr);
+        GraalBailoutException exception = new GraalBailoutException(message);
+        pendingException.set(exception);
+        return true;
+    }
+
+    private static final class ReturnFalseExceptionHandler implements CEntryPoint.ExceptionHandler {
+        @Uninterruptible(reason = "Exception handler")
+        @SuppressWarnings("unused")
+        static boolean handle(Throwable t) {
+            return false;
+        }
+    }
+
+    @CEntryPoint(include = CEntryPoint.NotIncludedAutomatically.class, publishAs = CEntryPoint.Publish.NotPublished)
+    @Uninterruptible(reason = "Called from exception handler, should not raise an exception.")
+    private static void dispatchExceptionWithoutMessage(@SuppressWarnings("unused") IsolateThread other) {
+        pendingException.set(EXCEPTION_WITHOUT_MESSAGE);
+    }
+}