[GR-9387] AssertionError in ContextProfile with multiple null contexts.

PullRequest: graal/1340
argan · Apr 17, 2018 · 595a0c6 · 595a0c6
2 parents 6a5f9e6 + e9d4aa3
commit 595a0c6
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Showing 3 changed files with 31 additions and 13 deletions.
diff --git a/...com.oracle.truffle.api.test/src/com/oracle/truffle/api/test/polyglot/LanguageSPITest.java b/...com.oracle.truffle.api.test/src/com/oracle/truffle/api/test/polyglot/LanguageSPITest.java
@@ -901,6 +901,23 @@ protected void disposeContext(LanguageContext context) {
         c.close();
     }
 
+    @Test
+    public void testNullContext() {
+        ProxyLanguage.setDelegate(new ProxyLanguage() {
+            @Override
+            protected LanguageContext createContext(TruffleLanguage.Env env) {
+                return null;
+            }
+        });
+        try (Engine engine = Engine.create()) {
+            for (int i = 0; i < 2; i++) {
+                try (Context context = Context.newBuilder(ProxyLanguage.ID).engine(engine).build()) {
+                    context.initialize(ProxyLanguage.ID);
+                }
+            }
+        }
+    }
+
     @Test
     public void testExceptionGetSourceLocation() {
         try (Context context = Context.create(LanguageSPITestLanguage.ID)) {

diff --git a/truffle/src/com.oracle.truffle.api.vm/src/com/oracle/truffle/api/vm/PolyglotLanguage.java b/truffle/src/com.oracle.truffle.api.vm/src/com/oracle/truffle/api/vm/PolyglotLanguage.java
@@ -142,8 +142,7 @@ void ensureInitialized() {
     ContextProfile requireProfile() {
         if (profile == null) {
             CompilerDirectives.transferToInterpreter();
-            throw new AssertionError(
-                            "No language context is active on this thread.");
+            throw new AssertionError("No language context is active on this thread.");
         }
         return profile;
     }
@@ -245,16 +244,15 @@ private Object lookupLanguageContext(PolyglotContextImpl context) {
             Env env = context.contexts[language.index].env;
             if (env == null) {
                 CompilerDirectives.transferToInterpreter();
-                throw new IllegalStateException(
-                                "The language context is not yet initialized or already disposed. ");
+                throw new IllegalStateException("The language context is not yet initialized or already disposed.");
             }
             return LANGUAGE.getContext(env);
         }
 
         void notifyContextCreate(Env env) {
             if (singleContext.isValid()) {
                 Object cachedSingle = this.cachedSingleContext;
-                assert cachedSingle != LANGUAGE.getContext(env);
+                assert cachedSingle != LANGUAGE.getContext(env) || cachedSingle == null : "Non-null context objects should be distinct";
                 if (cachedSingle == UNSET_CONTEXT) {
                     if (singleContext.isValid()) {
                         cachedSingleContext = LANGUAGE.getContext(env);

diff --git a/truffle/src/com.oracle.truffle.api/src/com/oracle/truffle/api/TruffleLanguage.java b/truffle/src/com.oracle.truffle.api/src/com/oracle/truffle/api/TruffleLanguage.java
@@ -31,6 +31,8 @@
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
+import java.net.URI;
+import java.nio.file.FileSystemNotFoundException;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.LinkedHashSet;
@@ -44,6 +46,7 @@
 import org.graalvm.options.OptionValues;
 import org.graalvm.polyglot.Context;
 import org.graalvm.polyglot.Value;
+import org.graalvm.polyglot.io.FileSystem;
 
 import com.oracle.truffle.api.CompilerDirectives.CompilationFinal;
 import com.oracle.truffle.api.CompilerDirectives.TruffleBoundary;
@@ -62,9 +65,6 @@
 import com.oracle.truffle.api.nodes.RootNode;
 import com.oracle.truffle.api.source.Source;
 import com.oracle.truffle.api.source.SourceSection;
-import java.net.URI;
-import java.nio.file.FileSystemNotFoundException;
-import org.graalvm.polyglot.io.FileSystem;
 
 /**
  * A Truffle language implementation contains all the services a language should provide to make it
@@ -90,7 +90,7 @@
  * that is created using the {@linkplain org.graalvm.polyglot.Engine.Builder#build() engine builder}
  * . If a {@linkplain org.graalvm.polyglot.Context context} is created without a
  * {@linkplain org.graalvm.polyglot.Engine engine} then the language implementation instance is
- * created for each context implicitely.
+ * created for each context implicitly.
  * <p>
  * Global state can be shared between multiple language context instances by saving them as in a
  * field of the {@link TruffleLanguage} subclass. The implementation needs to ensure data isolation
@@ -317,12 +317,15 @@ protected TruffleLanguage() {
      * {@link Env#parse(com.oracle.truffle.api.source.Source, java.lang.String...) calls into other
      * languages} and assuming your language is already initialized and others can see it would be
      * wrong - until you return from this method, the initialization isn't over. The same is true
-     * for instrumentation, the instruments can not receive any meta data about code executed during
+     * for instrumentation, the instruments cannot receive any meta data about code executed during
      * context creation. Should there be a need to perform complex initialization, do it by
      * overriding the {@link #initializeContext(java.lang.Object)} method.
+     * <p>
+     * May return {@code null} if the language does not need any per-{@linkplain Context context}
+     * state. Otherwise it should return a new object instance every time it is called.
      *
      * @param env the environment the language is supposed to operate in
-     * @return internal data of the language in given environment
+     * @return internal data of the language in given environment or {@code null}
      * @since 0.8 or earlier
      */
     protected abstract C createContext(Env env);
@@ -1307,7 +1310,7 @@ public Object getPolyglotBindings() {
         }
 
         /**
-         * Explicitely imports a symbol from the polyglot bindings. The behavior of this method is
+         * Explicitly imports a symbol from the polyglot bindings. The behavior of this method is
          * equivalent to sending a READ message to the {@link #getPolyglotBindings() polyglot
          * bindings} object. Reading a symbol that does not exist will return <code>null</code>.
          * <p>
@@ -1327,7 +1330,7 @@ public Object importSymbol(String symbolName) {
         }
 
         /**
-         * Explicitely exports a symbol to the polyglot bindings object. The behavior of this method
+         * Explicitly exports a symbol to the polyglot bindings object. The behavior of this method
          * is equivalent to sending a WRITE message to the {@link #getPolyglotBindings() polyglot
          * bindings} object. Exporting a symbol with a <code>null</code> value will remove the
          * symbol from the polyglot object.