Allow catching exceptions in other languages

- Add support for InteropLibrary's isException/throwException. - Change default for headless option to true (headless should only be false if TruffleSqueak is started through its launcher). - Throw SmalltalkExceptions as SqueakInteropException in case another language has triggered the code execution. This makes it possible to catch exceptions in other languages (e.g. JS: `try { Polyglot.eval("smalltalk", "1/0") } catch (error) { console.error("Got:", error) }`) - Update in-image code to include an appropriate test Closes #117
hpi-swa · Jun 17, 2020 · ddef572 · ddef572
1 parent f3b3dcc
commit ddef572
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Showing 8 changed files with 145 additions and 6 deletions.
diff --git a/src/de.hpi.swa.trufflesqueak.test/src/de/hpi/swa/trufflesqueak/test/tests.properties b/src/de.hpi.swa.trufflesqueak.test/src/de/hpi/swa/trufflesqueak/test/tests.properties
@@ -2611,6 +2611,7 @@ IntegerTest>>testSqrtFloor=passing
 IntegerTest>>testSqrtRem=passing
 IntegerTest>>testTwoComplementBitLogicWithCarry=passing
 IntegerTest>>testTwoComplementRightShift=passing
+InteropTest>>testExceptionHandling=passing
 InteropTest>>testMetadataAPIs=passing
 InteropTest>>testSmalltalkDNU=passing
 

diff --git a/src/de.hpi.swa.trufflesqueak/src/de/hpi/swa/trufflesqueak/SqueakOptions.java b/src/de.hpi.swa.trufflesqueak/src/de/hpi/swa/trufflesqueak/SqueakOptions.java
@@ -27,7 +27,7 @@ public final class SqueakOptions {
     public static final OptionKey<String> ImageArguments = new OptionKey<>("");
 
     @Option(name = SqueakLanguageOptions.HEADLESS, category = OptionCategory.USER, stability = OptionStability.STABLE, help = SqueakLanguageOptions.HEADLESS_HELP)//
-    public static final OptionKey<Boolean> Headless = new OptionKey<>(false);
+    public static final OptionKey<Boolean> Headless = new OptionKey<>(true);
 
     @Option(name = SqueakLanguageOptions.INTERCEPT_MESSAGES, category = OptionCategory.INTERNAL, stability = OptionStability.EXPERIMENTAL, help = SqueakLanguageOptions.INTERCEPT_MESSAGES_HELP)//
     public static final OptionKey<String> InterceptMessages = new OptionKey<>("");

diff --git a/src/de.hpi.swa.trufflesqueak/src/de/hpi/swa/trufflesqueak/exceptions/SqueakExceptions.java b/src/de.hpi.swa.trufflesqueak/src/de/hpi/swa/trufflesqueak/exceptions/SqueakExceptions.java
@@ -5,6 +5,7 @@
  */
 package de.hpi.swa.trufflesqueak.exceptions;
 
+import com.oracle.truffle.api.CompilerAsserts;
 import com.oracle.truffle.api.CompilerDirectives;
 import com.oracle.truffle.api.TruffleException;
 import com.oracle.truffle.api.nodes.ControlFlowException;
@@ -14,6 +15,7 @@
 import de.hpi.swa.trufflesqueak.SqueakLanguage;
 import de.hpi.swa.trufflesqueak.model.NativeObject;
 import de.hpi.swa.trufflesqueak.model.PointersObject;
+import de.hpi.swa.trufflesqueak.model.layout.ObjectLayouts.EXCEPTION;
 import de.hpi.swa.trufflesqueak.model.layout.ObjectLayouts.SYNTAX_ERROR_NOTIFICATION;
 import de.hpi.swa.trufflesqueak.nodes.AbstractNode;
 import de.hpi.swa.trufflesqueak.util.ArrayUtils;
@@ -159,6 +161,42 @@ public boolean isExit() {
         }
     }
 
+    public static final class SqueakInteropException extends RuntimeException implements TruffleException {
+        private static final long serialVersionUID = 1L;
+        private final PointersObject squeakException;
+
+        public SqueakInteropException(final PointersObject original) {
+            squeakException = original;
+        }
+
+        @Override
+        public String getMessage() {
+            CompilerAsserts.neverPartOfCompilation();
+            final Object messageText = squeakException.instVarAt0Slow(EXCEPTION.MESSAGE_TEXT);
+            if (messageText instanceof NativeObject && ((NativeObject) messageText).isString()) {
+                return ((NativeObject) messageText).asStringUnsafe();
+            } else {
+                return squeakException.toString();
+            }
+        }
+
+        @SuppressWarnings("sync-override")
+        @Override
+        public Throwable fillInStackTrace() {
+            return this;
+        }
+
+        @Override
+        public Object getExceptionObject() {
+            return squeakException;
+        }
+
+        @Override
+        public Node getLocation() {
+            return null;
+        }
+    }
+
     public static final class SqueakInterrupt extends RuntimeException implements TruffleException {
         private static final long serialVersionUID = 1L;
 

diff --git a/src/de.hpi.swa.trufflesqueak/src/de/hpi/swa/trufflesqueak/image/SqueakImageContext.java b/src/de.hpi.swa.trufflesqueak/src/de/hpi/swa/trufflesqueak/image/SqueakImageContext.java
@@ -138,6 +138,7 @@ public final class SqueakImageContext {
     public ContextObject lastSeenContext;
 
     @CompilationFinal private ClassObject compilerClass;
+    @CompilationFinal private ClassObject exceptionClass;
     @CompilationFinal private ClassObject parserClass;
     private PointersObject parserSharedInstance;
     @CompilationFinal private PointersObject scheduler;
@@ -381,6 +382,14 @@ public void setCompilerClass(final ClassObject classObject) {
         compilerClass = classObject;
     }
 
+    public ClassObject getExceptionClass() {
+        if (exceptionClass == null) {
+            CompilerDirectives.transferToInterpreterAndInvalidate();
+            exceptionClass = (ClassObject) evaluate("Exception");
+        }
+        return exceptionClass;
+    }
+
     public ClassObject getParserClass() {
         return parserClass;
     }

diff --git a/src/de.hpi.swa.trufflesqueak/src/de/hpi/swa/trufflesqueak/model/PointersObject.java b/src/de.hpi.swa.trufflesqueak/src/de/hpi/swa/trufflesqueak/model/PointersObject.java
@@ -6,7 +6,16 @@
 package de.hpi.swa.trufflesqueak.model;
 
 import com.oracle.truffle.api.CompilerAsserts;
-
+import com.oracle.truffle.api.dsl.Cached;
+import com.oracle.truffle.api.dsl.Cached.Shared;
+import com.oracle.truffle.api.dsl.CachedContext;
+import com.oracle.truffle.api.interop.InteropLibrary;
+import com.oracle.truffle.api.interop.UnsupportedMessageException;
+import com.oracle.truffle.api.library.ExportLibrary;
+import com.oracle.truffle.api.library.ExportMessage;
+
+import de.hpi.swa.trufflesqueak.SqueakLanguage;
+import de.hpi.swa.trufflesqueak.exceptions.SqueakExceptions.SqueakInteropException;
 import de.hpi.swa.trufflesqueak.image.SqueakImageChunk;
 import de.hpi.swa.trufflesqueak.image.SqueakImageContext;
 import de.hpi.swa.trufflesqueak.image.SqueakImageWriter;
@@ -19,11 +28,13 @@
 import de.hpi.swa.trufflesqueak.model.layout.ObjectLayouts.POINT;
 import de.hpi.swa.trufflesqueak.model.layout.ObjectLayouts.PROCESS;
 import de.hpi.swa.trufflesqueak.model.layout.ObjectLayouts.SPECIAL_OBJECT;
+import de.hpi.swa.trufflesqueak.nodes.InheritsFromNode;
 import de.hpi.swa.trufflesqueak.nodes.accessing.AbstractPointersObjectNodes.AbstractPointersObjectReadNode;
 import de.hpi.swa.trufflesqueak.nodes.accessing.AbstractPointersObjectNodes.AbstractPointersObjectWriteNode;
 import de.hpi.swa.trufflesqueak.nodes.accessing.SqueakObjectIdentityNode;
 import de.hpi.swa.trufflesqueak.util.ObjectGraphUtils.ObjectTracer;
 
+@ExportLibrary(InteropLibrary.class)
 public final class PointersObject extends AbstractPointersObject {
 
     public PointersObject(final SqueakImageContext image) {
@@ -187,4 +198,26 @@ public String toString() {
     public void write(final SqueakImageWriter writer) {
         super.writeHeaderAndLayoutObjects(writer);
     }
+
+    /*
+     * INTEROPERABILITY
+     */
+
+    @ExportMessage
+    protected static boolean isException(final PointersObject receiver,
+                    @Shared("inheritsFromNode") @Cached final InheritsFromNode inheritsFromNode,
+                    @CachedContext(SqueakLanguage.class) final SqueakImageContext image) {
+        return inheritsFromNode.execute(receiver, image.getExceptionClass());
+    }
+
+    @ExportMessage
+    protected static RuntimeException throwException(final PointersObject receiver,
+                    @Shared("inheritsFromNode") @Cached final InheritsFromNode inheritsFromNode,
+                    @CachedContext(SqueakLanguage.class) final SqueakImageContext image) throws UnsupportedMessageException {
+        if (isException(receiver, inheritsFromNode, image)) {
+            throw new SqueakInteropException(receiver);
+        } else {
+            throw UnsupportedMessageException.create();
+        }
+    }
 }
diff --git a/src/de.hpi.swa.trufflesqueak/src/de/hpi/swa/trufflesqueak/nodes/InheritsFromNode.java b/src/de.hpi.swa.trufflesqueak/src/de/hpi/swa/trufflesqueak/nodes/InheritsFromNode.java
@@ -6,11 +6,13 @@
 package de.hpi.swa.trufflesqueak.nodes;
 
 import com.oracle.truffle.api.dsl.Cached;
+import com.oracle.truffle.api.dsl.GenerateUncached;
 import com.oracle.truffle.api.dsl.Specialization;
 
 import de.hpi.swa.trufflesqueak.model.ClassObject;
 import de.hpi.swa.trufflesqueak.nodes.accessing.SqueakObjectClassNode;
 
+@GenerateUncached
 public abstract class InheritsFromNode extends AbstractNode {
     protected static final int CACHE_SIZE = 3;
 

diff --git a/...a.trufflesqueak/src/de/hpi/swa/trufflesqueak/nodes/primitives/impl/ContextPrimitives.java b/...a.trufflesqueak/src/de/hpi/swa/trufflesqueak/nodes/primitives/impl/ContextPrimitives.java
@@ -8,6 +8,7 @@
 import java.util.List;
 
 import com.oracle.truffle.api.CompilerDirectives.TruffleBoundary;
+import com.oracle.truffle.api.RootCallTarget;
 import com.oracle.truffle.api.Truffle;
 import com.oracle.truffle.api.dsl.Cached;
 import com.oracle.truffle.api.dsl.GenerateNodeFactory;
@@ -19,21 +20,27 @@
 import com.oracle.truffle.api.frame.FrameInstanceVisitor;
 import com.oracle.truffle.api.nodes.NodeCost;
 import com.oracle.truffle.api.nodes.NodeInfo;
+import com.oracle.truffle.api.nodes.RootNode;
 
+import de.hpi.swa.trufflesqueak.image.SqueakImageContext;
 import de.hpi.swa.trufflesqueak.model.AbstractSqueakObject;
+import de.hpi.swa.trufflesqueak.model.BooleanObject;
 import de.hpi.swa.trufflesqueak.model.CompiledCodeObject;
+import de.hpi.swa.trufflesqueak.model.CompiledMethodObject;
 import de.hpi.swa.trufflesqueak.model.ContextObject;
 import de.hpi.swa.trufflesqueak.model.FrameMarker;
 import de.hpi.swa.trufflesqueak.model.NilObject;
 import de.hpi.swa.trufflesqueak.model.layout.ObjectLayouts.CONTEXT;
 import de.hpi.swa.trufflesqueak.nodes.accessing.ContextObjectNodes.ContextObjectReadNode;
 import de.hpi.swa.trufflesqueak.nodes.accessing.ContextObjectNodes.ContextObjectWriteNode;
+import de.hpi.swa.trufflesqueak.nodes.bytecodes.MiscellaneousBytecodes.CallPrimitiveNode;
 import de.hpi.swa.trufflesqueak.nodes.primitives.AbstractPrimitiveFactoryHolder;
 import de.hpi.swa.trufflesqueak.nodes.primitives.AbstractPrimitiveNode;
 import de.hpi.swa.trufflesqueak.nodes.primitives.PrimitiveInterfaces.BinaryPrimitive;
 import de.hpi.swa.trufflesqueak.nodes.primitives.PrimitiveInterfaces.TernaryPrimitive;
 import de.hpi.swa.trufflesqueak.nodes.primitives.PrimitiveInterfaces.UnaryPrimitive;
 import de.hpi.swa.trufflesqueak.nodes.primitives.SqueakPrimitive;
+import de.hpi.swa.trufflesqueak.shared.SqueakLanguageConfig;
 import de.hpi.swa.trufflesqueak.util.FrameAccess;
 
 public class ContextPrimitives extends AbstractPrimitiveFactoryHolder {
@@ -192,6 +199,9 @@ private void terminateBetweenRecursively(final ContextObject start, final Contex
     @GenerateNodeFactory
     @SqueakPrimitive(indices = 197)
     protected abstract static class PrimNextHandlerContextNode extends AbstractPrimitiveNode implements UnaryPrimitive {
+        private ContextObject cachedContext;
+
+        @TruffleBoundary
         @Specialization(guards = {"receiver.hasMaterializedSender()"})
         protected static final AbstractSqueakObject findNext(final ContextObject receiver) {
             ContextObject context = receiver;
@@ -210,14 +220,25 @@ protected static final AbstractSqueakObject findNext(final ContextObject receive
             }
         }
 
+        @TruffleBoundary
         @Specialization(guards = {"!receiver.hasMaterializedSender()"})
-        protected static final AbstractSqueakObject findNextAvoidingMaterialization(final ContextObject receiver) {
+        protected final AbstractSqueakObject findNextAvoidingMaterialization(final ContextObject receiver) {
             final boolean[] foundMyself = new boolean[1];
             final Object[] lastSender = new Object[1];
             final ContextObject result = Truffle.getRuntime().iterateFrames(frameInstance -> {
                 final Frame current = frameInstance.getFrame(FrameInstance.FrameAccess.READ_ONLY);
                 if (!FrameAccess.isTruffleSqueakFrame(current)) {
-                    return null; // Foreign frame cannot be handler.
+                    final RootNode rootNode = ((RootCallTarget) frameInstance.getCallTarget()).getRootNode();
+                    if (rootNode.isInternal() || rootNode.getLanguageInfo().getId().equals(SqueakLanguageConfig.ID)) {
+                        /* Skip internal and all other nodes that belong to TruffleSqueak. */
+                        return null;
+                    } else {
+                        /*
+                         * Found a frame of another language. Stop here by returning the receiver
+                         * context. This special case will be handled later on.
+                         */
+                        return receiver;
+                    }
                 }
                 final ContextObject context = FrameAccess.getContext(current);
                 if (!foundMyself[0]) {
@@ -237,7 +258,13 @@ protected static final AbstractSqueakObject findNextAvoidingMaterialization(fina
                 }
                 return null;
             });
-            if (result == null) {
+            if (result == receiver) {
+                /*
+                 * Foreign frame found during frame iteration. Inject a fake context which will
+                 * throw the Smalltalk exception as polyglot exception.
+                 */
+                return getInteropExceptionThrowingContext();
+            } else if (result == null) {
                 if (!foundMyself[0]) {
                     return findNext(receiver); // Fallback to other version.
                 }
@@ -250,6 +277,35 @@ protected static final AbstractSqueakObject findNextAvoidingMaterialization(fina
                 return result;
             }
         }
+
+        /**
+         * Returns a fake context for BlockClosure>>#on:do: that handles any exception and rethrows
+         * it through Interop. This allows Smalltalk exceptions to be thrown to other languages, so
+         * that they can catch them. The mechanism works essentially like this:
+         *
+         * <pre>
+         * <code>[ ... ] on: Exception do: [ :e | Interop throwException: e exception ]</code>
+         * </pre>
+         *
+         * (see Context>>#handleSignal:)
+         */
+        private ContextObject getInteropExceptionThrowingContext() {
+            if (cachedContext == null) {
+                final SqueakImageContext image = lookupContext();
+                assert image.evaluate("Interop") != NilObject.SINGLETON : "Interop class must be present";
+                final CompiledMethodObject onDoMethod = (CompiledMethodObject) image.evaluate("BlockClosure>>#on:do:");
+                cachedContext = ContextObject.create(image, onDoMethod.getSqueakContextSize());
+                cachedContext.setMethod(onDoMethod);
+                cachedContext.setReceiver(NilObject.SINGLETON);
+                cachedContext.atTempPut(0, image.evaluate("Exception"));
+                cachedContext.atTempPut(1, image.evaluate("[ :e | Interop throwException: e exception ]"));
+                cachedContext.atTempPut(2, BooleanObject.TRUE);
+                cachedContext.setInstructionPointer(CallPrimitiveNode.NUM_BYTECODES);
+                cachedContext.setStackPointer(onDoMethod.getNumTemps());
+                cachedContext.removeSender();
+            }
+            return cachedContext.shallowCopy();
+        }
     }
 
     @NodeInfo(cost = NodeCost.NONE)

diff --git a/src/image b/src/image
+2 −2		src/BaselineOfTruffleSqueak.package/BaselineOfTruffleSqueak.class/instance/baseline..st
+8 −0		src/TruffleSqueak-Tests.package/InteropTest.class/instance/testExceptionHandling.st
+1 −0		src/TruffleSqueak-Tests.package/InteropTest.class/methodProperties.json