Optimize code loading and trigger const_added callback only if it's defined

Author: andrykonchin

src/main/java/org/truffleruby/RubyContext.java

@@ -159,6 +159,11 @@ public final class RubyContext {
     public long nativeArgv = 0L;
     public long nativeArgvLength = -1L;
 
+    // Whether or not a custom Module.const_added callback was defined.
+    // Optimization to avoid calling a default (empty) callback if there
+    // are no user-defined callbacks.
+    private volatile boolean constAddedDefined = false;
+
     private final AssumedValue<Boolean> warningCategoryDeprecated;
     private final AssumedValue<Boolean> warningCategoryExperimental;
 
@@ -444,7 +449,7 @@ private TruffleNFIPlatform createNativePlatform() {
 
     @TruffleBoundary
     public static Object send(Node currentNode, Object receiver, String methodName, Object... arguments) {
-        if (currentNode.isAdoptable()) {
+        if (currentNode != null && currentNode.isAdoptable()) {
             final EncapsulatingNodeReference callNodeRef = EncapsulatingNodeReference.getCurrent();
             final Node prev = callNodeRef.set(currentNode);
             try {
@@ -779,4 +784,12 @@ public void initializeMainScriptName(String mainScriptName) {
     public ImmutableRubyString getMainScriptName() {
         return this.mainScriptName;
     }
+
+    public boolean isConstAddedEverDefined() {
+        return constAddedDefined;
+    }
+
+    public void constAddedIsDefined() {
+        constAddedDefined = true;
+    }
 }

src/main/java/org/truffleruby/core/module/ModuleFields.java

@@ -30,7 +30,6 @@
 import org.truffleruby.RubyLanguage;
 import org.truffleruby.collections.ConcurrentOperations;
 import org.truffleruby.collections.ConcurrentWeakSet;
-import org.truffleruby.core.CoreLibrary;
 import org.truffleruby.core.encoding.Encodings;
 import org.truffleruby.core.encoding.TStringUtils;
 import org.truffleruby.core.kernel.KernelNodes;
@@ -496,8 +495,7 @@ private RubyConstant setConstantInternal(RubyContext context, Node currentNode,
             invalidateConstantIncludedBy(name);
         }
 
-        final CoreLibrary coreLibrary = context.getCoreLibrary();
-        if (currentNode != null && coreLibrary != null && coreLibrary.isLoaded()) {
+        if (context.isConstAddedEverDefined()) {
             final RubySymbol nameSymbol = context.getLanguageSlow().getSymbol(name);
             RubyContext.send(currentNode, rubyModule, "const_added", nameSymbol);
         }
@@ -579,6 +577,11 @@ public void addMethod(RubyContext context, Node currentNode, InternalMethod meth
                 }
             }
         }
+
+        // track if ever a custom Module.const_add callback is defined and ignore a default one
+        if (context.getCoreLibrary().isLoaded() && method.getName().equals("const_added")) {
+            RubyLanguage.getCurrentContext().constAddedIsDefined();
+        }
     }
 
     @TruffleBoundary