8348240: Remove SystemDictionaryShared::lookup_super_for_unregistered_class()

Reviewed-by: iklam
Backport-of: 7f16a0875ced8669b9d2131c67496a66e74ea36f

Author: TimPushkin

src/hotspot/share/cds/classListParser.cpp

@@ -42,6 +42,7 @@
 #include "jvm.h"
 #include "logging/log.hpp"
 #include "logging/logTag.hpp"
+#include "memory/oopFactory.hpp"
 #include "memory/resourceArea.hpp"
 #include "oops/constantPool.hpp"
 #include "runtime/atomic.hpp"
@@ -97,6 +98,12 @@ ClassListParser::~ClassListParser() {
   _instance = nullptr;
 }
 
+int ClassListParser::parse_classlist(const char* classlist_path, ParseMode parse_mode, TRAPS) {
+  UnregisteredClasses::initialize(CHECK_0);
+  ClassListParser parser(classlist_path, parse_mode);
+  return parser.parse(THREAD); // returns the number of classes loaded.
+}
+
 int ClassListParser::parse(TRAPS) {
   int class_count = 0;
 
@@ -390,6 +397,19 @@ bool ClassListParser::parse_uint_option(const char* option_name, int* value) {
   return false;
 }
 
+objArrayOop ClassListParser::get_specified_interfaces(TRAPS) {
+  const int n = _interfaces->length();
+  if (n == 0) {
+    return nullptr;
+  } else {
+    objArrayOop array = oopFactory::new_objArray(vmClasses::Class_klass(), n, CHECK_NULL);
+    for (int i = 0; i < n; i++) {
+      array->obj_at_put(i, lookup_class_by_id(_interfaces->at(i))->java_mirror());
+    }
+    return array;
+  }
+}
+
 void ClassListParser::print_specified_interfaces() {
   const int n = _interfaces->length();
   jio_fprintf(defaultStream::error_stream(), "Currently specified interfaces[%d] = {\n", n);
@@ -474,7 +494,17 @@ InstanceKlass* ClassListParser::load_class_from_source(Symbol* class_name, TRAPS
 
   ResourceMark rm;
   char * source_path = os::strdup_check_oom(ClassLoader::uri_to_path(_source));
-  InstanceKlass* k = UnregisteredClasses::load_class(class_name, source_path, CHECK_NULL);
+  InstanceKlass* specified_super = lookup_class_by_id(_super);
+  Handle super_class(THREAD, specified_super->java_mirror());
+  objArrayOop r = get_specified_interfaces(CHECK_NULL);
+  objArrayHandle interfaces(THREAD, r);
+  InstanceKlass* k = UnregisteredClasses::load_class(class_name, source_path,
+                                                     super_class, interfaces, CHECK_NULL);
+  if (k->java_super() != specified_super) {
+    error("The specified super class %s (id %d) does not match actual super class %s",
+          specified_super->external_name(), _super,
+          k->java_super()->external_name());
+  }
   if (k->local_interfaces()->length() != _interfaces->length()) {
     print_specified_interfaces();
     print_actual_interfaces(k);
@@ -682,46 +712,3 @@ InstanceKlass* ClassListParser::lookup_class_by_id(int id) {
   assert(*klass_ptr != nullptr, "must be");
   return *klass_ptr;
 }
-
-
-InstanceKlass* ClassListParser::lookup_super_for_current_class(Symbol* super_name) {
-  if (!is_loading_from_source()) {
-    return nullptr;
-  }
-
-  InstanceKlass* k = lookup_class_by_id(super());
-  if (super_name != k->name()) {
-    error("The specified super class %s (id %d) does not match actual super class %s",
-          k->name()->as_klass_external_name(), super(),
-          super_name->as_klass_external_name());
-  }
-  return k;
-}
-
-InstanceKlass* ClassListParser::lookup_interface_for_current_class(Symbol* interface_name) {
-  if (!is_loading_from_source()) {
-    return nullptr;
-  }
-
-  const int n = _interfaces->length();
-  if (n == 0) {
-    error("Class %s implements the interface %s, but no interface has been specified in the input line",
-          _class_name, interface_name->as_klass_external_name());
-    ShouldNotReachHere();
-  }
-
-  int i;
-  for (i=0; i<n; i++) {
-    InstanceKlass* k = lookup_class_by_id(_interfaces->at(i));
-    if (interface_name == k->name()) {
-      return k;
-    }
-  }
-
-  // interface_name is not specified by the "interfaces:" keyword.
-  print_specified_interfaces();
-  error("The interface %s implemented by class %s does not match any of the specified interface IDs",
-        interface_name->as_klass_external_name(), _class_name);
-  ShouldNotReachHere();
-  return nullptr;
-}

src/hotspot/share/cds/classListParser.hpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015, 2023, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2015, 2025, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -134,12 +134,10 @@ class ClassListParser : public StackObj {
 
   ClassListParser(const char* file, ParseMode _parse_mode);
   ~ClassListParser();
+  objArrayOop get_specified_interfaces(TRAPS);
 
 public:
-  static int parse_classlist(const char* classlist_path, ParseMode parse_mode, TRAPS) {
-    ClassListParser parser(classlist_path, parse_mode);
-    return parser.parse(THREAD); // returns the number of classes loaded.
-  }
+  static int parse_classlist(const char* classlist_path, ParseMode parse_mode, TRAPS);
 
   static bool is_parsing_thread();
   static ClassListParser* instance() {
@@ -192,11 +190,6 @@ class ClassListParser : public StackObj {
 
   bool lambda_form_line() { return _lambda_form_line; }
 
-  // Look up the super or interface of the current class being loaded
-  // (in this->load_current_class()).
-  InstanceKlass* lookup_super_for_current_class(Symbol* super_name);
-  InstanceKlass* lookup_interface_for_current_class(Symbol* interface_name);
-
   static void populate_cds_indy_info(const constantPoolHandle &pool, int cp_index, CDSIndyInfo* cii, TRAPS);
 };
 #endif // SHARE_CDS_CLASSLISTPARSER_HPP

src/hotspot/share/cds/unregisteredClasses.cpp

@@ -29,7 +29,7 @@
 #include "classfile/classLoaderExt.hpp"
 #include "classfile/javaClasses.inline.hpp"
 #include "classfile/symbolTable.hpp"
-#include "classfile/systemDictionaryShared.hpp"
+#include "classfile/systemDictionary.hpp"
 #include "classfile/vmSymbols.hpp"
 #include "memory/oopFactory.hpp"
 #include "memory/resourceArea.hpp"
@@ -39,76 +39,82 @@
 #include "runtime/javaCalls.hpp"
 #include "services/threadService.hpp"
 
+InstanceKlass* UnregisteredClasses::_UnregisteredClassLoader_klass = nullptr;
+
+void UnregisteredClasses::initialize(TRAPS) {
+  if (_UnregisteredClassLoader_klass == nullptr) {
+    // no need for synchronization as this function is called single-threaded.
+    Symbol* klass_name = SymbolTable::new_symbol("jdk/internal/misc/CDS$UnregisteredClassLoader");
+    Klass* k = SystemDictionary::resolve_or_fail(klass_name, true, CHECK);
+    _UnregisteredClassLoader_klass = InstanceKlass::cast(k);
+  }
+}
+
 // Load the class of the given name from the location given by path. The path is specified by
 // the "source:" in the class list file (see classListParser.cpp), and can be a directory or
 // a JAR file.
-InstanceKlass* UnregisteredClasses::load_class(Symbol* name, const char* path, TRAPS) {
+InstanceKlass* UnregisteredClasses::load_class(Symbol* name, const char* path,
+                                               Handle super_class, objArrayHandle interfaces, TRAPS) {
   assert(name != nullptr, "invariant");
   assert(DumpSharedSpaces, "this function is only used with -Xshare:dump");
 
   PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(),
                              THREAD->get_thread_stat()->perf_timers_addr(),
                              PerfClassTraceTime::CLASS_LOAD);
 
+  // Call CDS$UnregisteredClassLoader::load(String name, Class<?> superClass, Class<?>[] interfaces)
+  Symbol* methodName = SymbolTable::new_symbol("load");
+  Symbol* methodSignature = SymbolTable::new_symbol("(Ljava/lang/String;Ljava/lang/Class;[Ljava/lang/Class;)Ljava/lang/Class;");
   Symbol* path_symbol = SymbolTable::new_symbol(path);
-  Handle url_classloader = get_url_classloader(path_symbol, CHECK_NULL);
+  Handle classloader = get_classloader(path_symbol, CHECK_NULL);
   Handle ext_class_name = java_lang_String::externalize_classname(name, CHECK_NULL);
 
   JavaValue result(T_OBJECT);
-  JavaCallArguments args(2);
-  args.set_receiver(url_classloader);
+  JavaCallArguments args(3);
+  args.set_receiver(classloader);
   args.push_oop(ext_class_name);
-  args.push_int(JNI_FALSE);
+  args.push_oop(super_class);
+  args.push_oop(interfaces);
   JavaCalls::call_virtual(&result,
-                          vmClasses::URLClassLoader_klass(),
-                          vmSymbols::loadClass_name(),
-                          vmSymbols::string_boolean_class_signature(),
+                          UnregisteredClassLoader_klass(),
+                          methodName,
+                          methodSignature,
                           &args,
                           CHECK_NULL);
   assert(result.get_type() == T_OBJECT, "just checking");
   oop obj = result.get_oop();
   return InstanceKlass::cast(java_lang_Class::as_Klass(obj));
 }
 
-class URLClassLoaderTable : public ResourceHashtable<
+class UnregisteredClasses::ClassLoaderTable : public ResourceHashtable<
   Symbol*, OopHandle,
   137, // prime number
   AnyObj::C_HEAP> {};
 
-static URLClassLoaderTable* _url_classloader_table = nullptr;
+static UnregisteredClasses::ClassLoaderTable* _classloader_table = nullptr;
 
-Handle UnregisteredClasses::create_url_classloader(Symbol* path, TRAPS) {
+Handle UnregisteredClasses::create_classloader(Symbol* path, TRAPS) {
   ResourceMark rm(THREAD);
   JavaValue result(T_OBJECT);
   Handle path_string = java_lang_String::create_from_str(path->as_C_string(), CHECK_NH);
-  JavaCalls::call_static(&result,
-                         vmClasses::jdk_internal_loader_ClassLoaders_klass(),
-                         vmSymbols::toFileURL_name(),
-                         vmSymbols::toFileURL_signature(),
-                         path_string, CHECK_NH);
-  assert(result.get_type() == T_OBJECT, "just checking");
-  oop url_h = result.get_oop();
-  objArrayHandle urls = oopFactory::new_objArray_handle(vmClasses::URL_klass(), 1, CHECK_NH);
-  urls->obj_at_put(0, url_h);
-
-  Handle url_classloader = JavaCalls::construct_new_instance(
-                             vmClasses::URLClassLoader_klass(),
-                             vmSymbols::url_array_classloader_void_signature(),
-                             urls, Handle(), CHECK_NH);
-  return url_classloader;
+  Handle classloader = JavaCalls::construct_new_instance(
+                           UnregisteredClassLoader_klass(),
+                           vmSymbols::string_void_signature(),
+                           path_string, CHECK_NH);
+  return classloader;
 }
 
-Handle UnregisteredClasses::get_url_classloader(Symbol* path, TRAPS) {
-  if (_url_classloader_table == nullptr) {
-    _url_classloader_table = new (mtClass)URLClassLoaderTable();
+Handle UnregisteredClasses::get_classloader(Symbol* path, TRAPS) {
+  if (_classloader_table == nullptr) {
+    _classloader_table = new (mtClass)ClassLoaderTable();
   }
-  OopHandle* url_classloader_ptr = _url_classloader_table->get(path);
-  if (url_classloader_ptr != nullptr) {
-    return Handle(THREAD, (*url_classloader_ptr).resolve());
+  OopHandle* classloader_ptr = _classloader_table->get(path);
+  if (classloader_ptr != nullptr) {
+    return Handle(THREAD, (*classloader_ptr).resolve());
   } else {
-    Handle url_classloader = create_url_classloader(path, CHECK_NH);
-    _url_classloader_table->put(path, OopHandle(Universe::vm_global(), url_classloader()));
+    Handle classloader = create_classloader(path, CHECK_NH);
+    _classloader_table->put(path, OopHandle(Universe::vm_global(), classloader()));
     path->increment_refcount();
-    return url_classloader;
+    return classloader;
   }
 }

src/hotspot/share/cds/unregisteredClasses.hpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2021, 2025, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -25,15 +25,30 @@
 #ifndef SHARE_CDS_UNREGISTEREDCLASSES_HPP
 #define SHARE_CDS_UNREGISTEREDCLASSES_HPP
 
+#include "memory/allStatic.hpp"
 #include "runtime/handles.hpp"
 
+class InstanceKlass;
+class Symbol;
+
 class UnregisteredClasses: AllStatic {
 public:
-  static InstanceKlass* load_class(Symbol* h_name, const char* path, TRAPS);
+  static InstanceKlass* load_class(Symbol* h_name, const char* path,
+                                   Handle super_class, objArrayHandle interfaces,
+                                   TRAPS);
+  static void initialize(TRAPS);
+  static InstanceKlass* UnregisteredClassLoader_klass() {
+    return _UnregisteredClassLoader_klass;
+  }
+
+  class ClassLoaderTable;
 
 private:
-  static Handle create_url_classloader(Symbol* path, TRAPS);
-  static Handle get_url_classloader(Symbol* path, TRAPS);
+  // Don't put this in vmClasses as it's used only with CDS dumping.
+  static InstanceKlass* _UnregisteredClassLoader_klass;
+
+  static Handle create_classloader(Symbol* path, TRAPS);
+  static Handle get_classloader(Symbol* path, TRAPS);
 };
 
 #endif // SHARE_CDS_UNREGISTEREDCLASSES_HPP

src/hotspot/share/classfile/systemDictionary.cpp

@@ -412,16 +412,6 @@ InstanceKlass* SystemDictionary::resolve_super_or_fail(Symbol* class_name,
 
   assert(super_name != nullptr, "null superclass for resolving");
   assert(!Signature::is_array(super_name), "invalid superclass name");
-#if INCLUDE_CDS
-  if (DumpSharedSpaces) {
-    // Special processing for handling UNREGISTERED shared classes.
-    InstanceKlass* k = SystemDictionaryShared::lookup_super_for_unregistered_class(class_name,
-                           super_name, is_superclass);
-    if (k) {
-      return k;
-    }
-  }
-#endif // INCLUDE_CDS
 
   // If klass is already loaded, just return the superclass or superinterface.
   // Make sure there's a placeholder for the class_name before resolving.

src/hotspot/share/classfile/systemDictionaryShared.cpp

@@ -34,6 +34,7 @@
 #include "cds/dumpTimeClassInfo.inline.hpp"
 #include "cds/metaspaceShared.hpp"
 #include "cds/runTimeClassInfo.hpp"
+#include "cds/unregisteredClasses.hpp"
 #include "classfile/classFileStream.hpp"
 #include "classfile/classLoader.hpp"
 #include "classfile/classLoaderData.inline.hpp"
@@ -331,6 +332,12 @@ bool SystemDictionaryShared::check_for_exclusion_impl(InstanceKlass* k) {
     }
   }
 
+  if (k == UnregisteredClasses::UnregisteredClassLoader_klass()) {
+    ResourceMark rm;
+    log_info(cds)("Skipping %s: used only when dumping CDS archive", k->name()->as_C_string());
+    return true;
+  }
+
   return false; // false == k should NOT be excluded
 }
 
@@ -449,45 +456,6 @@ bool SystemDictionaryShared::add_unregistered_class(Thread* current, InstanceKla
   return (klass == *v);
 }
 
-// This function is called to lookup the super/interfaces of shared classes for
-// unregistered loaders. E.g., SharedClass in the below example
-// where "super:" (and optionally "interface:") have been specified.
-//
-// java/lang/Object id: 0
-// Interface    id: 2 super: 0 source: cust.jar
-// SharedClass  id: 4 super: 0 interfaces: 2 source: cust.jar
-InstanceKlass* SystemDictionaryShared::lookup_super_for_unregistered_class(
-    Symbol* class_name, Symbol* super_name, bool is_superclass) {
-
-  assert(DumpSharedSpaces, "only when static dumping");
-
-  if (!ClassListParser::is_parsing_thread()) {
-    // Unregistered classes can be created only by ClassListParser::_parsing_thread.
-
-    return nullptr;
-  }
-
-  ClassListParser* parser = ClassListParser::instance();
-  if (parser == nullptr) {
-    // We're still loading the well-known classes, before the ClassListParser is created.
-    return nullptr;
-  }
-  if (class_name->equals(parser->current_class_name())) {
-    // When this function is called, all the numbered super and interface types
-    // must have already been loaded. Hence this function is never recursively called.
-    if (is_superclass) {
-      return parser->lookup_super_for_current_class(super_name);
-    } else {
-      return parser->lookup_interface_for_current_class(super_name);
-    }
-  } else {
-    // The VM is not trying to resolve a super type of parser->current_class_name().
-    // Instead, it's resolving an error class (because parser->current_class_name() has
-    // failed parsing or verification). Don't do anything here.
-    return nullptr;
-  }
-}
-
 void SystemDictionaryShared::set_shared_class_misc_info(InstanceKlass* k, ClassFileStream* cfs) {
   Arguments::assert_is_dumping_archive();
   assert(!is_builtin(k), "must be unregistered class");