Add code comments for clarification

Author: olpaw

substratevm/src/com.oracle.svm.driver/src/com/oracle/svm/driver/DefaultOptionHandler.java

@@ -269,6 +269,10 @@ public boolean consume(ArgumentQueue args) {
             NativeImage.showWarning("Ignoring server-mode native-image argument " + headArg + ".");
             String serverOptionCommand = headArg.substring(serverOptionPrefix.length());
             if (!serverOptionCommand.startsWith("session=")) {
+                /*
+                 * All but the --server-session=... option used to exit(0). We want to simulate that
+                 * behaviour for proper backward compatibility.
+                 */
                 System.exit(0);
             }
             return true;

substratevm/src/com.oracle.svm.hosted/src/com/oracle/svm/hosted/phases/AnalysisGraphBuilderPhase.java

@@ -74,6 +74,13 @@ protected boolean tryInvocationPlugin(InvokeKind invokeKind, ValueNode[] args, R
         @Override
         protected boolean applyInvocationPlugin(InvokeKind invokeKind, ValueNode[] args, ResolvedJavaMethod targetMethod, JavaKind resultType, InvocationPlugin plugin) {
             Class<? extends InvocationPlugin> accessingClass = plugin.getClass();
+            /*
+             * The annotation-processor creates InvocationPlugins in classes in modules that e.g.
+             * use the @Fold annotation. This way InvocationPlugins can be in various classes in
+             * various modules. For these InvocationPlugins to do their work they need access to
+             * bits of graal. Thus the modules that contain such plugins need to be allowed such
+             * access.
+             */
             ModuleSupport.exportAndOpenPackageToClass("jdk.internal.vm.ci", "jdk.vm.ci.meta", false, accessingClass);
             ModuleSupport.exportAndOpenPackageToClass("jdk.internal.vm.compiler", "org.graalvm.compiler.nodes", false, accessingClass);
             return super.applyInvocationPlugin(invokeKind, args, targetMethod, resultType, plugin);