8264774: Implementation of Foreign Function and Memory API (Incubator)

Co-authored-by: Paul Sandoz <psandoz@openjdk.org>
Co-authored-by: Jorn Vernee <jvernee@openjdk.org>
Co-authored-by: Vladimir Ivanov <vlivanov@openjdk.org>
Co-authored-by: Athijegannathan Sundararajan <sundar@openjdk.org>
Co-authored-by: Chris Hegarty <chegar@openjdk.org>
Reviewed-by: psandoz, chegar, mchung, vlivanov

src/java.base/share/classes/java/lang/Module.java

@@ -109,6 +109,8 @@ public final class Module implements AnnotatedElement {
     // the module descriptor
     private final ModuleDescriptor descriptor;
 
+    // true, if this module allows restricted native access
+    private volatile boolean enableNativeAccess;
 
     /**
      * Creates a new named Module. The resulting Module will be defined to the
@@ -133,6 +135,10 @@ public final class Module implements AnnotatedElement {
         String loc = Objects.toString(uri, null);
         Object[] packages = descriptor.packages().toArray();
         defineModule0(this, isOpen, vs, loc, packages);
+        if (loader == null || loader == ClassLoaders.platformClassLoader()) {
+            // boot/builtin modules are always native
+            implAddEnableNativeAccess();
+        }
     }
 
 
@@ -244,6 +250,30 @@ public final class Module implements AnnotatedElement {
         return null;
     }
 
+    /**
+     * Update this module to allow access to restricted methods.
+     */
+    Module implAddEnableNativeAccess() {
+        enableNativeAccess = true;
+        return this;
+    }
+
+    /**
+     * Update all unnamed modules to allow access to restricted methods.
+     */
+    static void implAddEnableNativeAccessAllUnnamed() {
+        ALL_UNNAMED_MODULE.enableNativeAccess = true;
+    }
+
+    /**
+     * Returns true if module m can access restricted methods.
+     */
+    boolean implIsEnableNativeAccess() {
+        return isNamed() ?
+                enableNativeAccess :
+                ALL_UNNAMED_MODULE.enableNativeAccess;
+    }
+
     // --
 
     // special Module to mean "all unnamed modules"