Use the caller DefaultDefinee/cref for Kernel.{autoload,autoload?} like CRuby

Author: eregon

Diff for: src/main/java/org/truffleruby/core/klass/ClassNodes.java

@@ -335,6 +335,14 @@ protected Object getSuperClass(RubyClass rubyClass) {
         }
     }
 
+    @Primitive(name = "class_non_singleton_class")
+    public abstract static class NonSingletonClassNode extends PrimitiveArrayArgumentsNode {
+        @Specialization
+        protected RubyClass nonSingletonClass(RubyClass rubyClass) {
+            return rubyClass.nonSingletonClass;
+        }
+    }
+
     @CoreMethod(names = { "__allocate__", "__layout_allocate__" }, constructor = true, visibility = Visibility.PRIVATE)
     public abstract static class AllocateNode extends CoreMethodArrayArgumentsNode {
         @Specialization

Diff for: src/main/java/org/truffleruby/core/module/ModuleNodes.java

@@ -1744,6 +1744,20 @@ protected Object name(RubyModule module) {
         }
     }
 
+    @Primitive(name = "caller_declaration_context")
+    public abstract static class CallerDeclarationContextNode extends PrimitiveNode {
+        @TruffleBoundary
+        @Specialization
+        protected RubyModule callerDeclarationContext() {
+            var frame = getContext().getCallStack().getCallerFrame(FrameAccess.READ_ONLY);
+            if (frame == null) {
+                return coreLibrary().objectClass;
+            }
+            DeclarationContext declarationContext = RubyArguments.getDeclarationContext(frame.getArguments());
+            return declarationContext.getModuleToDefineMethods();
+        }
+    }
+
     @Primitive(name = "caller_nesting")
     public abstract static class CallerNestingNode extends PrimitiveArrayArgumentsNode {
         @Specialization

Diff for: src/main/ruby/truffleruby/core/kernel.rb

@@ -202,8 +202,8 @@ def abort(msg = nil)
   module_function :abort
 
   def autoload(name, file)
-    nesting = Primitive.caller_nesting
-    mod = nesting.first || Object
+    mod = Primitive.caller_declaration_context
+    mod = Primitive.class_non_singleton_class(mod) if Primitive.is_a?(mod, Class)
     if Primitive.equal?(mod, self)
       super(name, file) # Avoid recursion
     else
@@ -213,8 +213,7 @@ def autoload(name, file)
   module_function :autoload
 
   def autoload?(name)
-    nesting = Primitive.caller_nesting
-    mod = nesting.first || Object
+    mod = Primitive.caller_declaration_context
     if Primitive.equal?(mod, self)
       super(name) # Avoid recursion
     else