--- /dev/null
+diff --git a/src/share/vm/ci/ciObjectFactory.cpp b/src/share/vm/ci/ciObjectFactory.cpp
+index 079974f..6aaf349 100644
+--- a/src/share/vm/ci/ciObjectFactory.cpp
++++ b/src/share/vm/ci/ciObjectFactory.cpp
+@@ -800,3 +800,27 @@
+ _unloaded_instances->length(),
+ _unloaded_klasses->length());
+ }
++
++int ciObjectFactory::compare_cimetadata(ciMetadata** a, ciMetadata** b) {
++ Metadata* am = (*a)->constant_encoding();
++ Metadata* bm = (*b)->constant_encoding();
++ return ((am > bm) ? 1 : ((am == bm) ? 0 : -1));
++}
++
++// (DCEVM) Resoring the ciObject arrays after class redefinition
++void ciObjectFactory::resort_shared_ci_metadata() {
++ if (_shared_ci_metadata == NULL) return;
++ _shared_ci_metadata->sort(ciObjectFactory::compare_cimetadata);
++
++#ifdef ASSERT
++ if (CIObjectFactoryVerify) {
++ Metadata* last = NULL;
++ for (int j = 0; j< _shared_ci_metadata->length(); j++) {
++ Metadata* o = _shared_ci_metadata->at(j)->constant_encoding();
++ assert(last < o, "out of order");
++ last = o;
++ }
++ }
++#endif // ASSERT
++}
++
+diff --git a/src/share/vm/ci/ciObjectFactory.hpp b/src/share/vm/ci/ciObjectFactory.hpp
+index 4cdcc69..ffc2436 100644
+--- a/src/share/vm/ci/ciObjectFactory.hpp
++++ b/src/share/vm/ci/ciObjectFactory.hpp
+@@ -92,6 +92,7 @@
+
+ ciInstance* get_unloaded_instance(ciInstanceKlass* klass);
+
++ static int compare_cimetadata(ciMetadata** a, ciMetadata** b);
+ public:
+ static bool is_initialized() { return _initialized; }
+
+@@ -147,6 +148,8 @@
+
+ void print_contents();
+ void print();
++
++ static void resort_shared_ci_metadata();
+ };
+
+ #endif // SHARE_VM_CI_CIOBJECTFACTORY_HPP
+diff --git a/src/share/vm/classfile/classFileParser.cpp b/src/share/vm/classfile/classFileParser.cpp
+index 9678287..fa7986b 100644
+--- a/src/share/vm/classfile/classFileParser.cpp
++++ b/src/share/vm/classfile/classFileParser.cpp
+@@ -767,6 +767,7 @@
+ Array<Klass*>* ClassFileParser::parse_interfaces(int length,
+ Handle protection_domain,
+ Symbol* class_name,
++ bool pick_newest,
+ bool* has_default_methods,
+ TRAPS) {
+ if (length == 0) {
+@@ -785,7 +786,11 @@
+ "Interface name has bad constant pool index %u in class file %s",
+ interface_index, CHECK_NULL);
+ if (_cp->tag_at(interface_index).is_klass()) {
+- interf = KlassHandle(THREAD, _cp->resolved_klass_at(interface_index));
++ Klass* resolved_klass = _cp->resolved_klass_at(interface_index);
++ if (pick_newest) {
++ resolved_klass = resolved_klass->newest_version();
++ }
++ interf = KlassHandle(THREAD, resolved_klass);
+ } else {
+ Symbol* unresolved_klass = _cp->klass_name_at(interface_index);
+
+@@ -799,6 +804,9 @@
+ Klass* k = SystemDictionary::resolve_super_or_fail(class_name,
+ unresolved_klass, class_loader, protection_domain,
+ false, CHECK_NULL);
++ if (pick_newest) {
++ k = k->newest_version();
++ }
+ interf = KlassHandle(THREAD, k);
+ }
+
+@@ -3139,6 +3147,7 @@
+ }
+
+ instanceKlassHandle ClassFileParser::parse_super_class(int super_class_index,
++ bool pick_newest,
+ TRAPS) {
+ instanceKlassHandle super_klass;
+ if (super_class_index == 0) {
+@@ -3155,7 +3164,11 @@
+ // However, make sure it is not an array type.
+ bool is_array = false;
+ if (_cp->tag_at(super_class_index).is_klass()) {
+- super_klass = instanceKlassHandle(THREAD, _cp->resolved_klass_at(super_class_index));
++ Klass* resolved_klass = _cp->resolved_klass_at(super_class_index);
++ if (pick_newest) {
++ resolved_klass = resolved_klass->newest_version();
++ }
++ super_klass = instanceKlassHandle(THREAD, resolved_klass);
+ if (_need_verify)
+ is_array = super_klass->oop_is_array();
+ } else if (_need_verify) {
+@@ -3704,8 +3717,10 @@
+ instanceKlassHandle ClassFileParser::parseClassFile(Symbol* name,
+ ClassLoaderData* loader_data,
+ Handle protection_domain,
++ KlassHandle old_klass,
+ KlassHandle host_klass,
+ GrowableArray<Handle>* cp_patches,
++ GrowableArray<Symbol*>* parsed_super_symbols,
+ TempNewSymbol& parsed_name,
+ bool verify,
+ TRAPS) {
+@@ -3719,6 +3734,7 @@
+ Handle class_loader(THREAD, loader_data->class_loader());
+ bool has_default_methods = false;
+ bool declares_default_methods = false;
++ bool pick_newest = !old_klass.is_null();
+ ResourceMark rm(THREAD);
+
+ ClassFileStream* cfs = stream();
+@@ -3735,7 +3751,7 @@
+
+ init_parsed_class_attributes(loader_data);
+
+- if (JvmtiExport::should_post_class_file_load_hook()) {
++ if (parsed_super_symbols == NULL && JvmtiExport::should_post_class_file_load_hook()) {
+ // Get the cached class file bytes (if any) from the class that
+ // is being redefined or retransformed. We use jvmti_thread_state()
+ // instead of JvmtiThreadState::state_for(jt) so we don't allocate
+@@ -3896,6 +3912,26 @@
+ CHECK_(nullHandle));
+ }
+
++ // (DCEVM) Do not parse full class file, only get super symbols and return.
++ if (parsed_super_symbols != NULL) {
++ u2 super_class_index = cfs->get_u2_fast();
++
++ if (super_class_index != 0) {
++ parsed_super_symbols->append(cp->klass_name_at(super_class_index));
++ }
++
++ // Interfaces
++ u2 itfs_len = cfs->get_u2_fast();
++ Array<Klass*>* local_interfaces =
++ parse_interfaces(itfs_len, protection_domain, _class_name, pick_newest, &has_default_methods, CHECK_NULL);
++
++ for (int i = 0; i < local_interfaces->length(); i++) {
++ Klass* o = local_interfaces->at(i);
++ parsed_super_symbols->append(o->name());
++ }
++ return NULL;
++ }
++
+ Klass* preserve_this_klass; // for storing result across HandleMark
+
+ // release all handles when parsing is done
+@@ -3934,13 +3970,14 @@
+
+ u2 super_class_index = cfs->get_u2_fast();
+ instanceKlassHandle super_klass = parse_super_class(super_class_index,
++ pick_newest,
+ CHECK_NULL);
+
+ // Interfaces
+ u2 itfs_len = cfs->get_u2_fast();
+ Array<Klass*>* local_interfaces =
+ parse_interfaces(itfs_len, protection_domain, _class_name,
+- &has_default_methods, CHECK_(nullHandle));
++ pick_newest, &has_default_methods, CHECK_(nullHandle));
+
+ u2 java_fields_count = 0;
+ // Fields (offsets are filled in later)
+@@ -3994,6 +4031,9 @@
+ true,
+ CHECK_(nullHandle));
+
++ if (pick_newest) {
++ k = k->newest_version();
++ }
+ KlassHandle kh (THREAD, k);
+ super_klass = instanceKlassHandle(THREAD, kh());
+ }
+@@ -4159,7 +4199,7 @@
+ fill_oop_maps(this_klass, info.nonstatic_oop_map_count, info.nonstatic_oop_offsets, info.nonstatic_oop_counts);
+
+ // Fill in has_finalizer, has_vanilla_constructor, and layout_helper
+- set_precomputed_flags(this_klass);
++ set_precomputed_flags(this_klass, old_klass);
+
+ // reinitialize modifiers, using the InnerClasses attribute
+ int computed_modifiers = this_klass->compute_modifier_flags(CHECK_(nullHandle));
+@@ -4411,7 +4451,7 @@
+ }
+
+
+-void ClassFileParser::set_precomputed_flags(instanceKlassHandle k) {
++void ClassFileParser::set_precomputed_flags(instanceKlassHandle k, KlassHandle old_klass) {
+ Klass* super = k->super();
+
+ // Check if this klass has an empty finalize method (i.e. one with return bytecode only),
+@@ -4419,7 +4459,9 @@
+ if (!_has_empty_finalizer) {
+ if (_has_finalizer ||
+ (super != NULL && super->has_finalizer())) {
+- k->set_has_finalizer();
++ if (old_klass.is_null() || old_klass->has_finalizer()) {
++ k->set_has_finalizer();
++ }
+ }
+ }
+
+@@ -4441,7 +4483,7 @@
+
+ // Check if this klass supports the java.lang.Cloneable interface
+ if (SystemDictionary::Cloneable_klass_loaded()) {
+- if (k->is_subtype_of(SystemDictionary::Cloneable_klass())) {
++ if (k->is_subtype_of(SystemDictionary::Cloneable_klass()) || k->is_subtype_of(SystemDictionary::Cloneable_klass()->newest_version())) {
+ k->set_is_cloneable();
+ }
+ }
+diff --git a/src/share/vm/classfile/classFileParser.hpp b/src/share/vm/classfile/classFileParser.hpp
+index 74367f5..1e45e7f 100644
+--- a/src/share/vm/classfile/classFileParser.hpp
++++ b/src/share/vm/classfile/classFileParser.hpp
+@@ -219,11 +219,12 @@
+ Array<Klass*>* parse_interfaces(int length,
+ Handle protection_domain,
+ Symbol* class_name,
++ bool pick_newest,
+ bool* has_default_methods,
+ TRAPS);
+ void record_defined_class_dependencies(instanceKlassHandle defined_klass, TRAPS);
+
+- instanceKlassHandle parse_super_class(int super_class_index, TRAPS);
++ instanceKlassHandle parse_super_class(int super_class_index, bool pick_newest, TRAPS);
+ // Field parsing
+ void parse_field_attributes(u2 attributes_count,
+ bool is_static, u2 signature_index,
+@@ -305,7 +306,7 @@
+ unsigned int nonstatic_oop_map_count,
+ int* nonstatic_oop_offsets,
+ unsigned int* nonstatic_oop_counts);
+- void set_precomputed_flags(instanceKlassHandle k);
++ void set_precomputed_flags(instanceKlassHandle k, KlassHandle old_klass);
+ Array<Klass*>* compute_transitive_interfaces(instanceKlassHandle super,
+ Array<Klass*>* local_ifs, TRAPS);
+
+@@ -470,17 +471,20 @@
+ instanceKlassHandle parseClassFile(Symbol* name,
+ ClassLoaderData* loader_data,
+ Handle protection_domain,
++ KlassHandle old_klass,
+ TempNewSymbol& parsed_name,
+ bool verify,
+ TRAPS) {
+ KlassHandle no_host_klass;
+- return parseClassFile(name, loader_data, protection_domain, no_host_klass, NULL, parsed_name, verify, THREAD);
++ return parseClassFile(name, loader_data, protection_domain, old_klass, no_host_klass, NULL, NULL, parsed_name, verify, THREAD);
+ }
+ instanceKlassHandle parseClassFile(Symbol* name,
+ ClassLoaderData* loader_data,
+ Handle protection_domain,
++ KlassHandle old_klass,
+ KlassHandle host_klass,
+ GrowableArray<Handle>* cp_patches,
++ GrowableArray<Symbol*>* parsed_super_symbols,
+ TempNewSymbol& parsed_name,
+ bool verify,
+ TRAPS);
+diff --git a/src/share/vm/classfile/classLoader.cpp b/src/share/vm/classfile/classLoader.cpp
+index ef5766e..f74a3cd 100644
+--- a/src/share/vm/classfile/classLoader.cpp
++++ b/src/share/vm/classfile/classLoader.cpp
+@@ -1124,6 +1124,7 @@
+ instanceKlassHandle result = parser.parseClassFile(h_name,
+ loader_data,
+ protection_domain,
++ KlassHandle(),
+ parsed_name,
+ context.should_verify(classpath_index),
+ THREAD);
+diff --git a/src/share/vm/classfile/dictionary.cpp b/src/share/vm/classfile/dictionary.cpp
+index c9a43de..4e82b4e 100644
+--- a/src/share/vm/classfile/dictionary.cpp
++++ b/src/share/vm/classfile/dictionary.cpp
+@@ -156,7 +156,7 @@
+ InstanceKlass* ik = InstanceKlass::cast(e);
+
+ // Non-unloadable classes were handled in always_strong_oops_do
+- if (!is_strongly_reachable(loader_data, e)) {
++ if (!ik->is_redefining() && !is_strongly_reachable(loader_data, e)) {
+ // Entry was not visited in phase1 (negated test from phase1)
+ assert(!loader_data->is_the_null_class_loader_data(), "unloading entry with null class loader");
+ ClassLoaderData* k_def_class_loader_data = ik->class_loader_data();
+@@ -381,6 +381,32 @@
+ add_entry(index, entry);
+ }
+
++// (DCEVM) Updates the klass entry to point to the new Klass*. Necessary only for class redefinition.
++bool Dictionary::update_klass(int index, unsigned int hash, Symbol* name, ClassLoaderData* loader_data, KlassHandle k, KlassHandle old_class) {
++
++ // There are several entries for the same class in the dictionary: One extra entry for each parent classloader of the classloader of the class.
++ bool found = false;
++ for (int index = 0; index < table_size(); index++) {
++ for (DictionaryEntry* entry = bucket(index); entry != NULL; entry = entry->next()) {
++ if (entry->klass() == old_class()) {
++ entry->set_literal(k());
++ found = true;
++ }
++ }
++ }
++ return found;
++}
++
++// (DCEVM) Undo previous updates to the system dictionary
++void Dictionary::rollback_redefinition() {
++ for (int index = 0; index < table_size(); index++) {
++ for (DictionaryEntry* entry = bucket(index); entry != NULL; entry = entry->next()) {
++ if (entry->klass()->is_redefining()) {
++ entry->set_literal(entry->klass()->old_version());
++ }
++ }
++ }
++}
+
+ // This routine does not lock the system dictionary.
+ //
+@@ -411,7 +437,7 @@
+ ClassLoaderData* loader_data, Handle protection_domain, TRAPS) {
+ DictionaryEntry* entry = get_entry(index, hash, name, loader_data);
+ if (entry != NULL && entry->is_valid_protection_domain(protection_domain)) {
+- return entry->klass();
++ return intercept_for_version(entry->klass());
+ } else {
+ return NULL;
+ }
+@@ -424,7 +450,7 @@
+ assert (index == index_for(name, loader_data), "incorrect index?");
+
+ DictionaryEntry* entry = get_entry(index, hash, name, loader_data);
+- return (entry != NULL) ? entry->klass() : (Klass*)NULL;
++ return intercept_for_version((entry != NULL) ? entry->klass() : (Klass*)NULL);
+ }
+
+
+@@ -436,7 +462,7 @@
+ assert (index == index_for(name, NULL), "incorrect index?");
+
+ DictionaryEntry* entry = get_entry(index, hash, name, NULL);
+- return (entry != NULL) ? entry->klass() : (Klass*)NULL;
++ return intercept_for_version((entry != NULL) ? entry->klass() : (Klass*)NULL);
+ }
+
+
+diff --git a/src/share/vm/classfile/dictionary.hpp b/src/share/vm/classfile/dictionary.hpp
+index 504e735..c0948a6 100644
+--- a/src/share/vm/classfile/dictionary.hpp
++++ b/src/share/vm/classfile/dictionary.hpp
+@@ -81,6 +81,10 @@
+
+ void add_klass(Symbol* class_name, ClassLoaderData* loader_data,KlassHandle obj);
+
++ bool update_klass(int index, unsigned int hash, Symbol* name, ClassLoaderData* loader_data, KlassHandle k, KlassHandle old_class);
++
++ void rollback_redefinition();
++
+ Klass* find_class(int index, unsigned int hash,
+ Symbol* name, ClassLoaderData* loader_data);
+
+@@ -112,6 +116,11 @@
+ return (loader_data->is_the_null_class_loader_data() || !ClassUnloading);
+ }
+
++ // (DCEVM) During enhanced class redefinition we want old version if new is being redefined
++ static Klass* intercept_for_version(Klass* k) {
++ return (k != NULL && k->is_redefining()) ? k->old_version() : k;
++ }
++
+ // Unload (that is, break root links to) all unmarked classes and loaders.
+ void do_unloading();
+
+diff --git a/src/share/vm/classfile/javaClasses.cpp b/src/share/vm/classfile/javaClasses.cpp
+index b971d94..9848dc6 100644
+--- a/src/share/vm/classfile/javaClasses.cpp
++++ b/src/share/vm/classfile/javaClasses.cpp
+@@ -1709,6 +1709,8 @@
+ skip_throwableInit_check = true;
+ }
+ }
++ // (DCEVM): Line numbers from newest version must be used for EMCP-swapped methods
++ method = method->newest_version();
+ if (method->is_hidden()) {
+ if (skip_hidden) continue;
+ }
+diff --git a/src/share/vm/classfile/loaderConstraints.cpp b/src/share/vm/classfile/loaderConstraints.cpp
+index 8d59c00..f700f4f 100644
+--- a/src/share/vm/classfile/loaderConstraints.cpp
++++ b/src/share/vm/classfile/loaderConstraints.cpp
+@@ -98,6 +98,19 @@
+ return pp;
+ }
+
++void LoaderConstraintTable::update_after_redefinition() {
++ for (int index = 0; index < table_size(); index++) {
++ LoaderConstraintEntry** p = bucket_addr(index);
++ while(*p) {
++ LoaderConstraintEntry* probe = *p;
++ if (probe->klass() != NULL) {
++ // We swap the class with the newest version with an assumption that the hash will be the same
++ probe->set_klass(probe->klass()->newest_version());
++ }
++ p = probe->next_addr();
++ }
++ }
++}
+
+ void LoaderConstraintTable::purge_loader_constraints() {
+ assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
+@@ -446,7 +459,7 @@
+ if (k != NULL) {
+ // We found the class in the system dictionary, so we should
+ // make sure that the Klass* matches what we already have.
+- guarantee(k == probe->klass(), "klass should be in dictionary");
++ guarantee(k == probe->klass()->newest_version(), "klass should be in dictionary");
+ } else {
+ // If we don't find the class in the system dictionary, it
+ // has to be in the placeholders table.
+diff --git a/src/share/vm/classfile/loaderConstraints.hpp b/src/share/vm/classfile/loaderConstraints.hpp
+index 2b6d9b5..1f65c8d 100644
+--- a/src/share/vm/classfile/loaderConstraints.hpp
++++ b/src/share/vm/classfile/loaderConstraints.hpp
+@@ -64,6 +64,9 @@
+ // Enhanced Class Redefinition support
+ void classes_do(KlassClosure* f);
+
++ // (DCEVM) update all klasses with newest version
++ void update_after_redefinition();
++
+ // Check class loader constraints
+ bool add_entry(Symbol* name, Klass* klass1, Handle loader1,
+ Klass* klass2, Handle loader2);
+diff --git a/src/share/vm/classfile/systemDictionary.cpp b/src/share/vm/classfile/systemDictionary.cpp
+index 31be14b..e40b061 100644
+--- a/src/share/vm/classfile/systemDictionary.cpp
++++ b/src/share/vm/classfile/systemDictionary.cpp
+@@ -182,6 +182,7 @@
+ // can return a null klass
+ klass = handle_resolution_exception(class_name, class_loader, protection_domain, throw_error, k_h, THREAD);
+ }
++ assert(klass == NULL || klass->is_newest_version() || klass->newest_version()->is_redefining(), "must be");
+ return klass;
+ }
+
+@@ -224,7 +225,7 @@
+ // Forwards to resolve_instance_class_or_null
+
+ Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) {
+- assert(!THREAD->is_Compiler_thread(),
++ assert(!THREAD->is_Compiler_thread() || JvmtiThreadState::state_for(JavaThread::current())->get_class_being_redefined() != NULL,
+ err_msg("can not load classes with compiler thread: class=%s, classloader=%s",
+ class_name->as_C_string(),
+ class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string()));
+@@ -997,8 +998,10 @@
+ instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name,
+ loader_data,
+ protection_domain,
++ KlassHandle(),
+ host_klass,
+ cp_patches,
++ NULL,
+ parsed_name,
+ true,
+ THREAD);
+@@ -1052,6 +1055,7 @@
+ Handle protection_domain,
+ ClassFileStream* st,
+ bool verify,
++ KlassHandle old_class,
+ TRAPS) {
+
+ // Classloaders that support parallelism, e.g. bootstrap classloader,
+@@ -1079,9 +1083,15 @@
+ instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name,
+ loader_data,
+ protection_domain,
++ old_class,
+ parsed_name,
+ verify,
+ THREAD);
++ // (DCEVM) During enhanced class redefinition, mark loaded class as being redefined
++ if (!old_class.is_null() && !k.is_null()) {
++ k->set_redefining(true);
++ k->set_old_version(old_class());
++ }
+
+ const char* pkg = "java/";
+ if (!HAS_PENDING_EXCEPTION &&
+@@ -1116,10 +1126,11 @@
+ // Add class just loaded
+ // If a class loader supports parallel classloading handle parallel define requests
+ // find_or_define_instance_class may return a different InstanceKlass
+- if (is_parallelCapable(class_loader)) {
++ // (DCEVM) TODO: for class redefinition the parallel version does not work, check if this is a problem?
++ if (is_parallelCapable(class_loader) && old_class.is_null()) {
+ k = find_or_define_instance_class(class_name, class_loader, k, THREAD);
+ } else {
+- define_instance_class(k, THREAD);
++ define_instance_class(k, old_class, THREAD);
+ }
+ }
+
+@@ -1133,7 +1144,7 @@
+ MutexLocker mu(SystemDictionary_lock, THREAD);
+
+ Klass* check = find_class(parsed_name, loader_data);
+- assert(check == k(), "should be present in the dictionary");
++ assert((check == k() && !k->is_redefining()) || (k->is_redefining() && check == k->old_version()), "should be present in the dictionary");
+
+ Klass* check2 = find_class(h_name, defining_loader_data);
+ assert(check == check2, "name inconsistancy in SystemDictionary");
+@@ -1373,7 +1384,11 @@
+ }
+ }
+
+-void SystemDictionary::define_instance_class(instanceKlassHandle k, TRAPS) {
++void SystemDictionary::rollback_redefinition() {
++ dictionary()->rollback_redefinition();
++}
++
++void SystemDictionary::define_instance_class(instanceKlassHandle k, KlassHandle old_class, TRAPS) {
+
+ ClassLoaderData* loader_data = k->class_loader_data();
+ Handle class_loader_h(THREAD, loader_data->class_loader());
+@@ -1403,7 +1418,17 @@
+ Symbol* name_h = k->name();
+ unsigned int d_hash = dictionary()->compute_hash(name_h, loader_data);
+ int d_index = dictionary()->hash_to_index(d_hash);
+- check_constraints(d_index, d_hash, k, class_loader_h, true, CHECK);
++
++ // (DCEVM) Update version of the Klass* in the system dictionary
++ // TODO: Check for thread safety!
++ if (!old_class.is_null()) {
++ bool ok = dictionary()->update_klass(d_index, d_hash, name_h, loader_data, k, old_class);
++ assert (ok, "must have found old class and updated!");
++ }
++ check_constraints(d_index, d_hash, k, class_loader_h, old_class.is_null(), CHECK);
++
++ // FIXME: (DCEVM) clean this...
++ if(!old_class.is_null() && TraceRedefineClasses >= 3){ tty->print_cr("Class has been updated!"); }
+
+ // Register class just loaded with class loader (placed in Vector)
+ // Note we do this before updating the dictionary, as this can
+@@ -1436,8 +1461,9 @@
+ }
+ k->eager_initialize(THREAD);
+
++ // (DCEVM) Only notify jvmti if not redefining a class.
+ // notify jvmti
+- if (JvmtiExport::should_post_class_load()) {
++ if (JvmtiExport::should_post_class_load() && old_class.is_null()) {
+ assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
+ JvmtiExport::post_class_load((JavaThread *) THREAD, k());
+
+@@ -1511,7 +1537,7 @@
+ }
+ }
+
+- define_instance_class(k, THREAD);
++ define_instance_class(k, KlassHandle(), THREAD);
+
+ Handle linkage_exception = Handle(); // null handle
+
+@@ -1620,6 +1646,19 @@
+ return dictionary()->try_get_next_class();
+ }
+
++// (DCEVM) Remove from hierarchy - Undo add_to_hierarchy.
++void SystemDictionary::remove_from_hierarchy(instanceKlassHandle k) {
++ assert(k.not_null(), "just checking");
++
++ // remove receiver from sibling list
++ k->remove_from_sibling_list();
++ // TODO (DCEVM): Remove from interfaces.
++}
++
++// (DCEVM) Update constraints
++void SystemDictionary::update_constraints_after_redefinition() {
++ constraints()->update_after_redefinition();
++}
+
+ // ----------------------------------------------------------------------------
+ // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
+@@ -1997,7 +2036,7 @@
+ // also holds array classes
+
+ assert(check->oop_is_instance(), "noninstance in systemdictionary");
+- if ((defining == true) || (k() != check)) {
++ if ((defining == true) && ((k() != check) && k->old_version() != check)) {
+ linkage_error = "loader (instance of %s): attempted duplicate class "
+ "definition for name: \"%s\"";
+ } else {
+diff --git a/src/share/vm/classfile/systemDictionary.hpp b/src/share/vm/classfile/systemDictionary.hpp
+index cf5688a..25599e6 100644
+--- a/src/share/vm/classfile/systemDictionary.hpp
++++ b/src/share/vm/classfile/systemDictionary.hpp
+@@ -284,7 +284,7 @@
+ // Resolve from stream (called by jni_DefineClass and JVM_DefineClass)
+ static Klass* resolve_from_stream(Symbol* class_name, Handle class_loader,
+ Handle protection_domain,
+- ClassFileStream* st, bool verify, TRAPS);
++ ClassFileStream* st, bool verify, KlassHandle old_class, TRAPS);
+
+ // Lookup an already loaded class. If not found NULL is returned.
+ static Klass* find(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS);
+@@ -358,6 +358,12 @@
+ // System loader lock
+ static oop system_loader_lock() { return _system_loader_lock_obj; }
+
++ // (DCEVM) Remove link to hierarchy
++ static void remove_from_hierarchy(instanceKlassHandle k);
++
++ // (DCEVM) Update constraints
++ static void update_constraints_after_redefinition();
++
+ protected:
+ // Extended Redefine classes support (tbi)
+ static void preloaded_classes_do(KlassClosure* f);
+@@ -423,6 +429,9 @@
+ int limit = (int)end_id + 1;
+ initialize_wk_klasses_until((WKID) limit, start_id, THREAD);
+ }
++
++ // (DCEVM) rollback class redefinition
++ static void rollback_redefinition();
+
+ public:
+ #define WK_KLASS_DECLARE(name, symbol, option) \
+@@ -629,7 +638,7 @@
+ // after waiting, but before reentering SystemDictionary_lock
+ // to preserve lock order semantics.
+ static void double_lock_wait(Handle lockObject, TRAPS);
+- static void define_instance_class(instanceKlassHandle k, TRAPS);
++ static void define_instance_class(instanceKlassHandle k, KlassHandle old_class, TRAPS);
+ static instanceKlassHandle find_or_define_instance_class(Symbol* class_name,
+ Handle class_loader,
+ instanceKlassHandle k, TRAPS);
+diff --git a/src/share/vm/classfile/verifier.cpp b/src/share/vm/classfile/verifier.cpp
+index 58bd4f7..e2bab70 100644
+--- a/src/share/vm/classfile/verifier.cpp
++++ b/src/share/vm/classfile/verifier.cpp
+@@ -189,7 +189,7 @@
+ Symbol* name = klass->name();
+ Klass* refl_magic_klass = SystemDictionary::reflect_MagicAccessorImpl_klass();
+
+- bool is_reflect = refl_magic_klass != NULL && klass->is_subtype_of(refl_magic_klass);
++ bool is_reflect = refl_magic_klass != NULL && (klass->is_subtype_of(refl_magic_klass) || klass->is_subtype_of(refl_magic_klass->newest_version()));
+
+ return (should_verify_for(klass->class_loader(), should_verify_class) &&
+ // return if the class is a bootstrapping class
+@@ -529,7 +529,7 @@
+
+ ClassVerifier::ClassVerifier(
+ instanceKlassHandle klass, TRAPS)
+- : _thread(THREAD), _exception_type(NULL), _message(NULL), _klass(klass) {
++ : _thread(THREAD), _exception_type(NULL), _message(NULL), _klass(klass->newest_version()), _klass_to_verify(klass) {
+ _this_type = VerificationType::reference_type(klass->name());
+ // Create list to hold symbols in reference area.
+ _symbols = new GrowableArray<Symbol*>(100, 0, NULL);
+@@ -559,7 +559,7 @@
+ _klass->external_name());
+ }
+
+- Array<Method*>* methods = _klass->methods();
++ Array<Method*>* methods = _klass_to_verify->methods();
+ int num_methods = methods->length();
+
+ for (int index = 0; index < num_methods; index++) {
+diff --git a/src/share/vm/classfile/verifier.hpp b/src/share/vm/classfile/verifier.hpp
+index 96b6abe..659415a 100644
+--- a/src/share/vm/classfile/verifier.hpp
++++ b/src/share/vm/classfile/verifier.hpp
+@@ -344,6 +344,7 @@
+
+ VerificationType object_type() const;
+
++ instanceKlassHandle _klass_to_verify;
+ instanceKlassHandle _klass; // the class being verified
+ methodHandle _method; // current method being verified
+ VerificationType _this_type; // the verification type of the current class
+diff --git a/src/share/vm/interpreter/linkResolver.cpp b/src/share/vm/interpreter/linkResolver.cpp
+index 5a18a50..89a2a78 100644
+--- a/src/share/vm/interpreter/linkResolver.cpp
++++ b/src/share/vm/interpreter/linkResolver.cpp
+@@ -215,8 +215,8 @@
+ // Klass resolution
+
+ void LinkResolver::check_klass_accessability(KlassHandle ref_klass, KlassHandle sel_klass, TRAPS) {
+- if (!Reflection::verify_class_access(ref_klass(),
+- sel_klass(),
++ if (!Reflection::verify_class_access(ref_klass()->newest_version(),
++ sel_klass()->newest_version(),
+ true)) {
+ ResourceMark rm(THREAD);
+ Exceptions::fthrow(
+@@ -462,7 +462,7 @@
+ // We'll check for the method name first, as that's most likely
+ // to be false (so we'll short-circuit out of these tests).
+ if (sel_method->name() == vmSymbols::clone_name() &&
+- sel_klass() == SystemDictionary::Object_klass() &&
++ sel_klass()->newest_version() == SystemDictionary::Object_klass()->newest_version() &&
+ resolved_klass->oop_is_array()) {
+ // We need to change "protected" to "public".
+ assert(flags.is_protected(), "clone not protected?");
+@@ -811,7 +811,7 @@
+ }
+
+ // Final fields can only be accessed from its own class.
+- if (is_put && fd.access_flags().is_final() && sel_klass() != current_klass()) {
++ if (is_put && fd.access_flags().is_final() && sel_klass() != current_klass() && sel_klass() != current_klass()->active_version()) {
+ THROW(vmSymbols::java_lang_IllegalAccessError());
+ }
+
+@@ -1208,6 +1208,8 @@
+ // recv_klass might be an arrayKlassOop but all vtables start at
+ // the same place. The cast is to avoid virtual call and assertion.
+ InstanceKlass* inst = (InstanceKlass*)recv_klass();
++ // (DCEVM) Check that the receiver is a subtype of the holder of the resolved method.
++ assert(inst->is_subtype_of(resolved_method->method_holder()), "receiver and resolved method holder are inconsistent");
+ selected_method = methodHandle(THREAD, inst->method_at_vtable(vtable_index));
+ }
+ }
+diff --git a/src/share/vm/memory/universe.cpp b/src/share/vm/memory/universe.cpp
+index 4b81405..02be009 100644
+--- a/src/share/vm/memory/universe.cpp
++++ b/src/share/vm/memory/universe.cpp
+@@ -169,6 +169,43 @@
+ f(doubleArrayKlassObj());
+ }
+
++// (DCEVM) This method should iterate all pointers that are not within heap objects.
++void Universe::root_oops_do(OopClosure *oopClosure) {
++
++ class AlwaysTrueClosure: public BoolObjectClosure {
++ public:
++ void do_object(oop p) { ShouldNotReachHere(); }
++ bool do_object_b(oop p) { return true; }
++ };
++ AlwaysTrueClosure always_true;
++
++ Universe::oops_do(oopClosure);
++// ReferenceProcessor::oops_do(oopClosure); (tw) check why no longer there
++ JNIHandles::oops_do(oopClosure); // Global (strong) JNI handles
++ Threads::oops_do(oopClosure, NULL, NULL);
++ ObjectSynchronizer::oops_do(oopClosure);
++ FlatProfiler::oops_do(oopClosure);
++ JvmtiExport::oops_do(oopClosure);
++
++ // Now adjust pointers in remaining weak roots. (All of which should
++ // have been cleared if they pointed to non-surviving objects.)
++ // Global (weak) JNI handles
++ JNIHandles::weak_oops_do(&always_true, oopClosure);
++
++ CodeBlobToOopClosure blobClosure(oopClosure, CodeBlobToOopClosure::FixRelocations);
++ CodeCache::blobs_do(&blobClosure);
++ StringTable::oops_do(oopClosure);
++
++ // (DCEVM) TODO: Check if this is correct?
++ //CodeCache::scavenge_root_nmethods_oops_do(oopClosure);
++ //Management::oops_do(oopClosure);
++ //ref_processor()->weak_oops_do(&oopClosure);
++ //PSScavenge::reference_processor()->weak_oops_do(&oopClosure);
++
++ // SO_AllClasses
++ SystemDictionary::oops_do(oopClosure);
++}
++
+ void Universe::oops_do(OopClosure* f, bool do_all) {
+
+ f->do_oop((oop*) &_int_mirror);
+diff --git a/src/share/vm/memory/universe.hpp b/src/share/vm/memory/universe.hpp
+index 9180901..689e403 100644
+--- a/src/share/vm/memory/universe.hpp
++++ b/src/share/vm/memory/universe.hpp
+@@ -416,6 +416,7 @@
+ static void run_finalizers_on_exit();
+
+ // Iteration
++ static void root_oops_do(OopClosure *f);
+
+ // Apply "f" to the addresses of all the direct heap pointers maintained
+ // as static fields of "Universe".
+diff --git a/src/share/vm/oops/cpCache.cpp b/src/share/vm/oops/cpCache.cpp
+index d0c7750..60f92ca 100644
+--- a/src/share/vm/oops/cpCache.cpp
++++ b/src/share/vm/oops/cpCache.cpp
+@@ -338,7 +338,8 @@
+ if (has_appendix) {
+ const int appendix_index = f2_as_index() + _indy_resolved_references_appendix_offset;
+ assert(appendix_index >= 0 && appendix_index < resolved_references->length(), "oob");
+- assert(resolved_references->obj_at(appendix_index) == NULL, "init just once");
++ // FIXME (DCEVM) relaxing for now...
++ //assert(resolved_references->obj_at(appendix_index) == NULL, "init just once");
+ resolved_references->obj_at_put(appendix_index, appendix());
+ }
+
+@@ -346,7 +347,8 @@
+ if (has_method_type) {
+ const int method_type_index = f2_as_index() + _indy_resolved_references_method_type_offset;
+ assert(method_type_index >= 0 && method_type_index < resolved_references->length(), "oob");
+- assert(resolved_references->obj_at(method_type_index) == NULL, "init just once");
++ // FIXME (DCEVM) relaxing for now...
++ //assert(resolved_references->obj_at(method_type_index) == NULL, "init just once");
+ resolved_references->obj_at_put(method_type_index, method_type());
+ }
+
+@@ -530,6 +532,22 @@
+ // the method is in the interesting class so the entry is interesting
+ return m;
+ }
++
++// Enhanced RedefineClasses() API support (DCEVM):
++// Clear cached entry, let it be re-resolved
++void ConstantPoolCacheEntry::clear_entry() {
++ _indices = constant_pool_index();
++ _f1 = NULL;
++ if (!is_resolved_reference()) {
++ _f2 = 0;
++ }
++ // FIXME: (DCEVM) we want to clear flags, but parameter size is actually used
++ // after we return from the method, before entry is re-initialized. So let's
++ // keep parameter size the same.
++ // For example, it's used in TemplateInterpreterGenerator::generate_return_entry_for
++ // Also, we need to keep flag marking entry as one containing resolved_reference
++ _flags &= parameter_size_mask | (1 << is_resolved_ref_shift);
++}
+ #endif // INCLUDE_JVMTI
+
+ void ConstantPoolCacheEntry::print(outputStream* st, int index) const {
+@@ -643,6 +661,14 @@
+ }
+ }
+ }
++
++// Enhanced RedefineClasses() API support (DCEVM):
++// Clear all entries
++void ConstantPoolCache::clear_entries() {
++ for (int i = 0; i < length(); i++) {
++ entry_at(i)->clear_entry();
++ }
++}
+ #endif // INCLUDE_JVMTI
+
+
+diff --git a/src/share/vm/oops/cpCache.hpp b/src/share/vm/oops/cpCache.hpp
+index d3bc3a2..fef14a7 100644
+--- a/src/share/vm/oops/cpCache.hpp
++++ b/src/share/vm/oops/cpCache.hpp
+@@ -179,6 +179,8 @@
+ tos_state_bits = 4,
+ tos_state_mask = right_n_bits(tos_state_bits),
+ tos_state_shift = BitsPerInt - tos_state_bits, // see verify_tos_state_shift below
++ // (DCEVM) We need to remember entries which has resolved reference indices as we don't want to clean them
++ is_resolved_ref_shift = 27,
+ // misc. option bits; can be any bit position in [16..27]
+ is_field_entry_shift = 26, // (F) is it a field or a method?
+ has_method_type_shift = 25, // (M) does the call site have a MethodType?
+@@ -211,6 +213,7 @@
+ void initialize_resolved_reference_index(int ref_index) {
+ assert(_f2 == 0, "set once"); // note: ref_index might be zero also
+ _f2 = ref_index;
++ _flags = 1 << is_resolved_ref_shift;
+ }
+
+ void set_field( // sets entry to resolved field state
+@@ -348,6 +351,7 @@
+ bool is_final() const { return (_flags & (1 << is_final_shift)) != 0; }
+ bool is_forced_virtual() const { return (_flags & (1 << is_forced_virtual_shift)) != 0; }
+ bool is_vfinal() const { return (_flags & (1 << is_vfinal_shift)) != 0; }
++ bool is_resolved_reference() const { return (_flags & (1 << is_resolved_ref_shift)) != 0; }
+ bool has_appendix() const { return (!is_f1_null()) && (_flags & (1 << has_appendix_shift)) != 0; }
+ bool has_method_type() const { return (!is_f1_null()) && (_flags & (1 << has_method_type_shift)) != 0; }
+ bool is_method_entry() const { return (_flags & (1 << is_field_entry_shift)) == 0; }
+@@ -376,6 +380,10 @@
+ bool* trace_name_printed);
+ bool check_no_old_or_obsolete_entries();
+ Method* get_interesting_method_entry(Klass* k);
++
++ // Enhanced RedefineClasses() API support (DCEVM):
++ // Clear cached entry, let it be re-resolved
++ void clear_entry();
+ #endif // INCLUDE_JVMTI
+
+ // Debugging & Printing
+@@ -474,6 +482,10 @@
+ void adjust_method_entries(InstanceKlass* holder, bool* trace_name_printed);
+ bool check_no_old_or_obsolete_entries();
+ void dump_cache();
++
++ // Enhanced RedefineClasses() API support (DCEVM):
++ // Clear all entries
++ void clear_entries();
+ #endif // INCLUDE_JVMTI
+
+ // Deallocate - no fields to deallocate
+diff --git a/src/share/vm/oops/instanceKlass.cpp b/src/share/vm/oops/instanceKlass.cpp
+index 481742d..e7fd7ba 100644
+--- a/src/share/vm/oops/instanceKlass.cpp
++++ b/src/share/vm/oops/instanceKlass.cpp
+@@ -745,7 +745,8 @@
+ }
+ #endif
+ this_oop->set_init_state(linked);
+- if (JvmtiExport::should_post_class_prepare()) {
++ // (DCEVM) Must check for old version in order to prevent infinite loops.
++ if (JvmtiExport::should_post_class_prepare() && this_oop->old_version() == NULL /* JVMTI deadlock otherwise */) {
+ Thread *thread = THREAD;
+ assert(thread->is_Java_thread(), "thread->is_Java_thread()");
+ JvmtiExport::post_class_prepare((JavaThread *) thread, this_oop());
+@@ -857,7 +858,9 @@
+ // If we were to use wait() instead of waitInterruptibly() then
+ // we might end up throwing IE from link/symbol resolution sites
+ // that aren't expected to throw. This would wreak havoc. See 6320309.
+- while(this_oop->is_being_initialized() && !this_oop->is_reentrant_initialization(self)) {
++ // (DCEVM) Wait also for the old class version to be fully initialized.
++ while((this_oop->is_being_initialized() && !this_oop->is_reentrant_initialization(self))
++ || (this_oop->old_version() != NULL && InstanceKlass::cast(this_oop->old_version())->is_being_initialized())) {
+ wait = true;
+ ol.waitUninterruptibly(CHECK);
+ }
+@@ -1091,6 +1094,18 @@
+ assert(k->is_interface(), "should be an interface class");
+ for (int i = 0; i < transitive_interfaces()->length(); i++) {
+ if (transitive_interfaces()->at(i) == k) {
++ return true;
++ }
++ }
++ return false;
++}
++
++bool InstanceKlass::implements_interface_any_version(Klass* k) const {
++ k = k->newest_version();
++ if (this->newest_version() == k) return true;
++ assert(k->is_interface(), "should be an interface class");
++ for (int i = 0; i < transitive_interfaces()->length(); i++) {
++ if (transitive_interfaces()->at(i)->newest_version() == k) {
+ return true;
+ }
+ }
+@@ -1364,6 +1379,18 @@
+ }
+ }
+
++void InstanceKlass::store_update_information(GrowableArray<int> &values) {
++ int *arr = NEW_C_HEAP_ARRAY(int, values.length(), mtClass);
++ for (int i=0; i<values.length(); i++) {
++ arr[i] = values.at(i);
++ }
++ set_update_information(arr);
++}
++
++void InstanceKlass::clear_update_information() {
++ FREE_C_HEAP_ARRAY(int, update_information(), mtClass);
++ set_update_information(NULL);
++}
+
+ void InstanceKlass::do_local_static_fields(FieldClosure* cl) {
+ for (JavaFieldStream fs(this); !fs.done(); fs.next()) {
+@@ -1978,6 +2005,18 @@
+ _dependencies = new nmethodBucket(nm, _dependencies);
+ }
+
++bool InstanceKlass::update_jmethod_id(Method* method, jmethodID newMethodID) {
++ size_t idnum = (size_t)method->method_idnum();
++ jmethodID* jmeths = methods_jmethod_ids_acquire();
++ size_t length; // length assigned as debugging crumb
++ jmethodID id = NULL;
++ if (jmeths != NULL && // If there is a cache
++ (length = (size_t)jmeths[0]) > idnum) { // and if it is long enough,
++ jmeths[idnum+1] = newMethodID; // Set method id (may be NULL)
++ return true;
++ }
++ return false;
++}
+
+ //
+ // Decrement count of the nmethod in the dependency list and remove
+@@ -2011,6 +2050,13 @@
+ last = b;
+ b = b->next();
+ }
++
++ // (DCEVM) Hack as dependencies get wrong version of Klass*
++ if (this->old_version() != NULL) {
++ InstanceKlass::cast(this->old_version())->remove_dependent_nmethod(nm, true);
++ return;
++ }
++
+ #ifdef ASSERT
+ tty->print_cr("### %s can't find dependent nmethod:", this->external_name());
+ nm->print();
+@@ -3068,6 +3114,24 @@
+ assert(is_klass(), "must be klass");
+ Klass::print_on(st);
+
++ // (DCEVM) Output revision number and revision numbers of older / newer and oldest / newest version of this class.
++ if (AllowEnhancedClassRedefinition) {
++ st->print(BULLET"revision: %d", revision_number());
++ if (new_version() != NULL) {
++ st->print(" (newer=%d)", new_version()->revision_number());
++ }
++ if (newest_version() != new_version() && newest_version() != this) {
++ st->print(" (newest=%d)", newest_version()->revision_number());
++ }
++ if (old_version() != NULL) {
++ st->print(" (old=%d)", old_version()->revision_number());
++ }
++ if (oldest_version() != old_version() && oldest_version() != this) {
++ st->print(" (oldest=%d)", oldest_version()->revision_number());
++ }
++ st->cr();
++ }
++
+ st->print(BULLET"instance size: %d", size_helper()); st->cr();
+ st->print(BULLET"klass size: %d", size()); st->cr();
+ st->print(BULLET"access: "); access_flags().print_on(st); st->cr();
+@@ -3399,7 +3463,7 @@
+ }
+
+ guarantee(sib->is_klass(), "should be klass");
+- guarantee(sib->super() == super, "siblings should have same superklass");
++ guarantee(sib->super() == super || super->newest_version() == SystemDictionary::Object_klass(), "siblings should have same superklass");
+ }
+
+ // Verify implementor fields
+@@ -3564,6 +3628,7 @@
+
+ // Purge previous versions
+ static void purge_previous_versions_internal(InstanceKlass* ik, int emcp_method_count) {
++ // FIXME: (DCEVM) Should we purge something?
+ if (ik->previous_versions() != NULL) {
+ // This klass has previous versions so see what we can cleanup
+ // while it is safe to do so.
+@@ -3801,7 +3866,7 @@
+
+ // Determine if InstanceKlass has a previous version.
+ bool InstanceKlass::has_previous_version() const {
+- return (_previous_versions != NULL && _previous_versions->length() > 0);
++ return _old_version != NULL || (_previous_versions != NULL && _previous_versions->length() > 0);
+ } // end has_previous_version()
+
+
+diff --git a/src/share/vm/oops/instanceKlass.hpp b/src/share/vm/oops/instanceKlass.hpp
+index dc4a565..d6d23f8 100644
+--- a/src/share/vm/oops/instanceKlass.hpp
++++ b/src/share/vm/oops/instanceKlass.hpp
+@@ -139,6 +139,7 @@
+ friend class VMStructs;
+ friend class ClassFileParser;
+ friend class CompileReplay;
++ friend class VM_EnhancedRedefineClasses;
+
+ protected:
+ // Constructor
+@@ -651,7 +652,7 @@
+ // If the _previous_versions array is non-NULL, then this klass
+ // has been redefined at least once even if we aren't currently
+ // tracking a previous version.
+- bool has_been_redefined() const { return _previous_versions != NULL; }
++ bool has_been_redefined() const { return _old_version != NULL || _previous_versions != NULL; }
+ bool has_previous_version() const;
+ void init_previous_versions() {
+ _previous_versions = NULL;
+@@ -737,6 +738,7 @@
+ static void get_jmethod_id_length_value(jmethodID* cache, size_t idnum,
+ size_t *length_p, jmethodID* id_p);
+ jmethodID jmethod_id_or_null(Method* method);
++ bool update_jmethod_id(Method* method, jmethodID newMethodID);
+
+ // annotations support
+ Annotations* annotations() const { return _annotations; }
+@@ -807,6 +809,7 @@
+ // subclass/subinterface checks
+ bool implements_interface(Klass* k) const;
+ bool is_same_or_direct_interface(Klass* k) const;
++ bool implements_interface_any_version(Klass* k) const;
+
+ #ifdef ASSERT
+ // check whether this class or one of its superclasses was redefined
+@@ -863,6 +866,10 @@
+ void do_nonstatic_fields(FieldClosure* cl); // including inherited fields
+ void do_local_static_fields(void f(fieldDescriptor*, Handle, TRAPS), Handle, TRAPS);
+
++ // (DCEVM) instance update information to be used in GC run
++ void store_update_information(GrowableArray<int> &values);
++ void clear_update_information();
++
+ void methods_do(void f(Method* method));
+ void array_klasses_do(void f(Klass* k));
+ void array_klasses_do(void f(Klass* k, TRAPS), TRAPS);
+diff --git a/src/share/vm/oops/klass.cpp b/src/share/vm/oops/klass.cpp
+index 7b01be6..2e3d192 100644
+--- a/src/share/vm/oops/klass.cpp
++++ b/src/share/vm/oops/klass.cpp
+@@ -186,6 +186,13 @@
+ set_next_link(NULL);
+ TRACE_INIT_ID(this);
+
++ set_redefinition_flags(Klass::NoRedefinition);
++ set_redefining(false);
++ set_new_version(NULL);
++ set_old_version(NULL);
++ set_redefinition_index(-1);
++ set_revision_number(-1);
++
+ set_prototype_header(markOopDesc::prototype());
+ set_biased_lock_revocation_count(0);
+ set_last_biased_lock_bulk_revocation_time(0);
+@@ -392,6 +399,24 @@
+ debug_only(verify();)
+ }
+
++// (DCEVM)
++void Klass::remove_from_sibling_list() {
++ debug_only(verify();)
++ // remove ourselves to superklass' subklass list
++ InstanceKlass* super = superklass();
++ assert(super != NULL, "should have super");
++ if (super->subklass() == this) {
++ // first subklass
++ super->set_subklass(next_sibling());
++ } else {
++ Klass* sib = super->subklass();
++ while (sib->next_sibling() != this) {
++ sib = sib->next_sibling();
++ };
++ sib->set_next_sibling(next_sibling());
++ }
++}
++
+ bool Klass::is_loader_alive(BoolObjectClosure* is_alive) {
+ #ifdef ASSERT
+ // The class is alive iff the class loader is alive.
+diff --git a/src/share/vm/oops/klass.hpp b/src/share/vm/oops/klass.hpp
+index 3222dc9..e3fc3bd 100644
+--- a/src/share/vm/oops/klass.hpp
++++ b/src/share/vm/oops/klass.hpp
+@@ -149,6 +149,10 @@
+ oop _java_mirror;
+ // Superclass
+ Klass* _super;
++ // Old class
++ Klass* _old_version;
++ // New class
++ Klass* _new_version;
+ // First subclass (NULL if none); _subklass->next_sibling() is next one
+ Klass* _subklass;
+ // Sibling link (or NULL); links all subklasses of a klass
+@@ -163,6 +167,16 @@
+
+ jint _modifier_flags; // Processed access flags, for use by Class.getModifiers.
+ AccessFlags _access_flags; // Access flags. The class/interface distinction is stored here.
++
++ // (DCEVM) fields for enhanced class redefinition
++ jint _revision_number; // The revision number for redefined classes
++ jint _redefinition_index; // Index of this class when performing the redefinition
++ bool _subtype_changed;
++ int _redefinition_flags; // Level of class redefinition
++ bool _is_copying_backwards; // Does the class need to copy fields backwards? => possibly overwrite itself?
++ bool _original_field_offsets_changed; // Did the original field offsets of this class change during class redefinition?
++ int * _update_information; // Update information
++ bool _is_redefining;
+
+ // Biased locking implementation and statistics
+ // (the 64-bit chunk goes first, to avoid some fragmentation)
+@@ -220,6 +234,53 @@
+ Array<Klass*>* secondary_supers() const { return _secondary_supers; }
+ void set_secondary_supers(Array<Klass*>* k) { _secondary_supers = k; }
+
++ // BEGIN class redefinition utilities
++
++ // double links between new and old version of a class
++ Klass* old_version() const { return _old_version; }
++ void set_old_version(Klass* klass) { assert(_old_version == NULL || klass == NULL, "Can only be set once!"); _old_version = klass; }
++ Klass* new_version() const { return _new_version; }
++ void set_new_version(Klass* klass) { assert(_new_version == NULL || klass == NULL, "Can only be set once!"); _new_version = klass; }
++
++ // A subtype of this class is no longer a subtype
++ bool has_subtype_changed() const { return _subtype_changed; }
++ void set_subtype_changed(bool b) { assert(is_newest_version() || new_version()->is_newest_version(), "must be newest or second newest version");
++ _subtype_changed = b; }
++ // state of being redefined
++ int redefinition_index() const { return _redefinition_index; }
++ void set_redefinition_index(int index) { _redefinition_index = index; }
++ void set_redefining(bool b) { _is_redefining = b; }
++ bool is_redefining() const { return _is_redefining; }
++ int redefinition_flags() const { return _redefinition_flags; }
++ bool check_redefinition_flag(int flags) const { return (_redefinition_flags & flags) != 0; }
++ void set_redefinition_flags(int flags) { _redefinition_flags = flags; }
++ void set_redefinition_flag(int flag) { _redefinition_flags |= flag; }
++ void clear_redefinition_flag(int flag) { _redefinition_flags &= ~flag; }
++ bool is_copying_backwards() const { return _is_copying_backwards; }
++ void set_copying_backwards(bool b) { _is_copying_backwards = b; }
++
++ // update information
++ int *update_information() const { return _update_information; }
++ void set_update_information(int *info) { _update_information = info; }
++
++ // Revision number for redefined classes, -1 for originally loaded classes
++ bool was_redefined() const { return _revision_number != -1; }
++ jint revision_number() const { return _revision_number; }
++ void set_revision_number(jint number) { _revision_number = number; }
++
++ const Klass* oldest_version() const { return _old_version == NULL ? this : _old_version->oldest_version(); }
++ Klass* oldest_version() { return _old_version == NULL ? this : _old_version->oldest_version(); }
++
++ const Klass* newest_version() const { return _new_version == NULL ? this : _new_version->newest_version(); }
++ Klass* newest_version() { return _new_version == NULL ? this : _new_version->newest_version(); }
++
++ const Klass* active_version() const { return _new_version == NULL || _new_version->is_redefining() ? this : _new_version->active_version(); }
++ Klass* active_version() { return _new_version == NULL || _new_version->is_redefining() ? this : _new_version->active_version(); }
++
++ bool is_newest_version() const { return _new_version == NULL; }
++
++ // END class redefinition utilities
++
+ // Return the element of the _super chain of the given depth.
+ // If there is no such element, return either NULL or this.
+ Klass* primary_super_of_depth(juint i) const {
+@@ -273,6 +334,7 @@
+ Klass* subklass() const;
+ Klass* next_sibling() const;
+ void append_to_sibling_list(); // add newly created receiver to superklass' subklass list
++ void remove_from_sibling_list(); // (DCEVM) remove receiver from sibling list
+
+ void set_next_link(Klass* k) { _next_link = k; }
+ Klass* next_link() const { return _next_link; } // The next klass defined by the class loader.
+@@ -308,6 +370,16 @@
+ void set_next_sibling(Klass* s);
+
+ public:
++ // (DCEVM) Different class redefinition flags of code evolution.
++ enum RedefinitionFlags {
++ NoRedefinition, // This class is not redefined at all!
++ ModifyClass = 1, // There are changes to the class meta data.
++ ModifyClassSize = ModifyClass << 1, // The size of the class meta data changes.
++ ModifyInstances = ModifyClassSize << 1, // There are change to the instance format.
++ ModifyInstanceSize = ModifyInstances << 1, // The size of instances changes.
++ RemoveSuperType = ModifyInstanceSize << 1, // A super type of this class is removed.
++ MarkedAsAffected = RemoveSuperType << 1 // This class has been marked as an affected class.
++ };
+
+ // Compiler support
+ static ByteSize super_offset() { return in_ByteSize(offset_of(Klass, _super)); }
+diff --git a/src/share/vm/oops/klassVtable.cpp b/src/share/vm/oops/klassVtable.cpp
+index 639ce01..740b2f4 100644
+--- a/src/share/vm/oops/klassVtable.cpp
++++ b/src/share/vm/oops/klassVtable.cpp
+@@ -1510,6 +1510,8 @@
+
+ void klassVtable::verify_against(outputStream* st, klassVtable* vt, int index) {
+ vtableEntry* vte = &vt->table()[index];
++ // (DCEVM) FIXME-isd: do we need the following line?
++ if (vte->method() == NULL || table()[index].method() == NULL) return;
+ if (vte->method()->name() != table()[index].method()->name() ||
+ vte->method()->signature() != table()[index].method()->signature()) {
+ fatal("mismatched name/signature of vtable entries");
+@@ -1529,6 +1531,8 @@
+
+ void vtableEntry::verify(klassVtable* vt, outputStream* st) {
+ NOT_PRODUCT(FlagSetting fs(IgnoreLockingAssertions, true));
++ // FIXME: (DCEVM) does not hold?
++ if (method() != NULL) {
+ assert(method() != NULL, "must have set method");
+ method()->verify();
+ // we sub_type, because it could be a miranda method
+@@ -1536,7 +1540,9 @@
+ #ifndef PRODUCT
+ print();
+ #endif
+- fatal(err_msg("vtableEntry " PTR_FORMAT ": method is from subclass", this));
++ // (DCEVM) the following fatal does not work for old versions of classes
++ //fatal(err_msg("vtableEntry " PTR_FORMAT ": method is from subclass", this));
++ }
+ }
+ }
+
+diff --git a/src/share/vm/oops/method.cpp b/src/share/vm/oops/method.cpp
+index b1db4dc..f395654 100644
+--- a/src/share/vm/oops/method.cpp
++++ b/src/share/vm/oops/method.cpp
+@@ -1226,6 +1226,8 @@
+
+ // Reset correct method/const method, method size, and parameter info
+ newm->set_constMethod(newcm);
++ newm->set_new_version(newm->new_version());
++ newm->set_old_version(newm->old_version());
+ newm->constMethod()->set_code_size(new_code_length);
+ newm->constMethod()->set_constMethod_size(new_const_method_size);
+ newm->set_method_size(new_method_size);
+@@ -1841,6 +1843,10 @@
+
+ // Add a method id to the jmethod_ids
+ jmethodID Method::make_jmethod_id(ClassLoaderData* loader_data, Method* m) {
++ // FIXME: (DCEVM) ???
++ if (m != m->newest_version()) {
++ m = m->newest_version();
++ }
+ ClassLoaderData* cld = loader_data;
+
+ if (!SafepointSynchronize::is_at_safepoint()) {
+diff --git a/src/share/vm/oops/method.hpp b/src/share/vm/oops/method.hpp
+index 974bced..da98bf5 100644
+--- a/src/share/vm/oops/method.hpp
++++ b/src/share/vm/oops/method.hpp
+@@ -104,6 +104,9 @@
+ MethodCounters* _method_counters;
+ AccessFlags _access_flags; // Access flags
+ int _vtable_index; // vtable index of this method (see VtableIndexFlag)
++ // (DCEVM) Newer version of method available?
++ Method* _new_version;
++ Method* _old_version;
+ // note: can have vtables with >2**16 elements (because of inheritance)
+ u2 _method_size; // size of this object
+ u1 _intrinsic_id; // vmSymbols::intrinsic_id (0 == _none)
+@@ -175,6 +178,23 @@
+ int name_index() const { return constMethod()->name_index(); }
+ void set_name_index(int index) { constMethod()->set_name_index(index); }
+
++ Method* new_version() const { return _new_version; }
++ void set_new_version(Method* m) { _new_version = m; }
++ Method* newest_version() { return (_new_version == NULL) ? this : _new_version->newest_version(); }
++
++ Method* old_version() const { return _old_version; }
++ void set_old_version(Method* m) {
++ /*if (m == NULL) {
++ _old_version = NULL;
++ return;
++ }*/
++
++ assert(_old_version == NULL, "may only be set once");
++ assert(this->code_size() == m->code_size(), "must have same code length");
++ _old_version = m;
++ }
++ const Method* oldest_version() const { return (_old_version == NULL) ? this : _old_version->oldest_version(); }
++
+ // signature
+ Symbol* signature() const { return constants()->symbol_at(signature_index()); }
+ int signature_index() const { return constMethod()->signature_index(); }
+diff --git a/src/share/vm/prims/jni.cpp b/src/share/vm/prims/jni.cpp
+index 8a41ca4..25d985d 100644
+--- a/src/share/vm/prims/jni.cpp
++++ b/src/share/vm/prims/jni.cpp
+@@ -399,6 +399,7 @@
+ }
+ Klass* k = SystemDictionary::resolve_from_stream(class_name, class_loader,
+ Handle(), &st, true,
++ KlassHandle(),
+ CHECK_NULL);
+
+ if (TraceClassResolution && k != NULL) {
+diff --git a/src/share/vm/prims/jvm.cpp b/src/share/vm/prims/jvm.cpp
+index b989224..d41127b 100644
+--- a/src/share/vm/prims/jvm.cpp
++++ b/src/share/vm/prims/jvm.cpp
+@@ -1029,6 +1029,7 @@
+ Klass* k = SystemDictionary::resolve_from_stream(class_name, class_loader,
+ protection_domain, &st,
+ verify != 0,
++ KlassHandle(),
+ CHECK_NULL);
+
+ if (TraceClassResolution && k != NULL) {
+diff --git a/src/share/vm/prims/jvmtiEnv.cpp b/src/share/vm/prims/jvmtiEnv.cpp
+index 0c92c88..9cafbd1 100644
+--- a/src/share/vm/prims/jvmtiEnv.cpp
++++ b/src/share/vm/prims/jvmtiEnv.cpp
+@@ -43,6 +43,7 @@
+ #include "prims/jvmtiManageCapabilities.hpp"
+ #include "prims/jvmtiRawMonitor.hpp"
+ #include "prims/jvmtiRedefineClasses.hpp"
++#include "prims/jvmtiRedefineClasses2.hpp"
+ #include "prims/jvmtiTagMap.hpp"
+ #include "prims/jvmtiThreadState.inline.hpp"
+ #include "prims/jvmtiUtil.hpp"
+@@ -207,8 +208,10 @@
+ // is_modifiable_class_ptr - pre-checked for NULL
+ jvmtiError
+ JvmtiEnv::IsModifiableClass(oop k_mirror, jboolean* is_modifiable_class_ptr) {
+- *is_modifiable_class_ptr = VM_RedefineClasses::is_modifiable_class(k_mirror)?
+- JNI_TRUE : JNI_FALSE;
++ bool is_modifiable_class = AllowEnhancedClassRedefinition ?
++ VM_EnhancedRedefineClasses::is_modifiable_class(k_mirror) :
++ VM_RedefineClasses::is_modifiable_class(k_mirror);
++ *is_modifiable_class_ptr = is_modifiable_class ? JNI_TRUE : JNI_FALSE;
+ return JVMTI_ERROR_NONE;
+ } /* end IsModifiableClass */
+
+@@ -277,6 +280,11 @@
+ }
+ class_definitions[index].klass = jcls;
+ }
++ if (AllowEnhancedClassRedefinition) {
++ VM_EnhancedRedefineClasses op(class_count, class_definitions, jvmti_class_load_kind_retransform);
++ VMThread::execute(&op);
++ return (op.check_error());
++ }
+ VM_RedefineClasses op(class_count, class_definitions, jvmti_class_load_kind_retransform);
+ VMThread::execute(&op);
+ return (op.check_error());
+@@ -288,6 +296,11 @@
+ jvmtiError
+ JvmtiEnv::RedefineClasses(jint class_count, const jvmtiClassDefinition* class_definitions) {
+ //TODO: add locking
++ if (AllowEnhancedClassRedefinition) {
++ VM_EnhancedRedefineClasses op(class_count, class_definitions, jvmti_class_load_kind_redefine);
++ VMThread::execute(&op);
++ return (op.check_error());
++ }
+ VM_RedefineClasses op(class_count, class_definitions, jvmti_class_load_kind_redefine);
+ VMThread::execute(&op);
+ return (op.check_error());
+diff --git a/src/share/vm/prims/jvmtiExport.hpp b/src/share/vm/prims/jvmtiExport.hpp
+index 4b1ff34..3f8280e 100644
+--- a/src/share/vm/prims/jvmtiExport.hpp
++++ b/src/share/vm/prims/jvmtiExport.hpp
+@@ -188,6 +188,7 @@
+ // systems as needed to relax invariant checks.
+ static bool _has_redefined_a_class;
+ friend class VM_RedefineClasses;
++ friend class VM_EnhancedRedefineClasses;
+ inline static void set_has_redefined_a_class() {
+ JVMTI_ONLY(_has_redefined_a_class = true;)
+ }
+diff --git a/src/share/vm/prims/jvmtiImpl.cpp b/src/share/vm/prims/jvmtiImpl.cpp
+index 9b308d4..aa0f08b 100644
+--- a/src/share/vm/prims/jvmtiImpl.cpp
++++ b/src/share/vm/prims/jvmtiImpl.cpp
+@@ -290,6 +290,11 @@
+ Symbol* m_name = _method->name();
+ Symbol* m_signature = _method->signature();
+
++ // (DCEVM) Go through old versions of method
++ for (Method* m = _method->old_version(); m != NULL; m = m->old_version()) {
++ (m->*meth_act)(_bci);
++ }
++
+ // search previous versions if they exist
+ PreviousVersionWalker pvw(thread, (InstanceKlass *)ikh());
+ for (PreviousVersionNode * pv_node = pvw.next_previous_version();
+diff --git a/src/share/vm/prims/jvmtiRedefineClasses2.cpp b/src/share/vm/prims/jvmtiRedefineClasses2.cpp
+new file mode 100644
+index 0000000..2519da8
+--- /dev/null
++++ b/src/share/vm/prims/jvmtiRedefineClasses2.cpp
+@@ -0,0 +1,2119 @@
++/*
++ * Copyright (c) 2003, 2011, 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
++ * under the terms of the GNU General Public License version 2 only, as
++ * published by the Free Software Foundation.
++ *
++ * This code is distributed in the hope that it will be useful, but WITHOUT
++ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
++ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
++ * version 2 for more details (a copy is included in the LICENSE file that
++ * accompanied this code).
++ *
++ * You should have received a copy of the GNU General Public License version
++ * 2 along with this work; if not, write to the Free Software Foundation,
++ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
++ *
++ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
++ * or visit www.oracle.com if you need additional information or have any
++ * questions.
++ *
++ */
++
++#include "precompiled.hpp"
++#include "classfile/systemDictionary.hpp"
++#include "classfile/verifier.hpp"
++#include "code/codeCache.hpp"
++#include "interpreter/oopMapCache.hpp"
++#include "interpreter/rewriter.hpp"
++#include "memory/gcLocker.hpp"
++#include "memory/universe.inline.hpp"
++#include "memory/metaspaceShared.hpp"
++#include "oops/fieldStreams.hpp"
++#include "oops/klassVtable.hpp"
++#include "prims/jvmtiImpl.hpp"
++#include "prims/jvmtiRedefineClasses2.hpp"
++#include "prims/methodComparator.hpp"
++#include "prims/jvmtiClassFileReconstituter.hpp"
++#include "runtime/deoptimization.hpp"
++#include "runtime/relocator.hpp"
++#include "utilities/bitMap.inline.hpp"
++#include "compiler/compileBroker.hpp"
++#include "oops/instanceMirrorKlass.hpp"
++#include "utilities/pair.hpp"
++
++
++Array<Method*>* VM_EnhancedRedefineClasses::_old_methods = NULL;
++Array<Method*>* VM_EnhancedRedefineClasses::_new_methods = NULL;
++int* VM_EnhancedRedefineClasses::_matching_old_methods = NULL;
++int* VM_EnhancedRedefineClasses::_matching_new_methods = NULL;
++int* VM_EnhancedRedefineClasses::_deleted_methods = NULL;
++int* VM_EnhancedRedefineClasses::_added_methods = NULL;
++int VM_EnhancedRedefineClasses::_matching_methods_length = 0;
++int VM_EnhancedRedefineClasses::_deleted_methods_length = 0;
++int VM_EnhancedRedefineClasses::_added_methods_length = 0;
++GrowableArray<instanceKlassHandle>* VM_EnhancedRedefineClasses::_affected_klasses = NULL;
++
++
++// Holds the revision number of the current class redefinition
++int VM_EnhancedRedefineClasses::_revision_number = -1;
++
++VM_EnhancedRedefineClasses::VM_EnhancedRedefineClasses(jint class_count, const jvmtiClassDefinition *class_defs, JvmtiClassLoadKind class_load_kind)
++ : VM_GC_Operation(Universe::heap()->total_full_collections(), GCCause::_heap_inspection) {
++ RC_TIMER_START(_timer_total);
++ _class_count = class_count;
++ _class_defs = class_defs;
++ _class_load_kind = class_load_kind;
++ _result = JVMTI_ERROR_NONE;
++}
++
++VM_EnhancedRedefineClasses::~VM_EnhancedRedefineClasses() {
++ RC_TIMER_STOP(_timer_total);
++}
++
++void VM_EnhancedRedefineClasses::add_affected_klasses( Klass* klass )
++{
++ assert(!_affected_klasses->contains(klass), "must not occur more than once!");
++ assert(klass->new_version() == NULL, "Only last version is valid entry in system dictionary");
++
++ if (klass->check_redefinition_flag(Klass::MarkedAsAffected)) {
++ _affected_klasses->append(klass);
++ return;
++ }
++
++ for (juint i = 0; i < klass->super_depth(); i++) {
++ Klass* primary = klass->primary_super_of_depth(i);
++ // super_depth returns "8" for interfaces, but they don't have primaries other than Object.
++ if (primary == NULL) {
++ break;
++ }
++ if (primary->check_redefinition_flag(Klass::MarkedAsAffected)) {
++ RC_TRACE(0x00000001, ("Found affected class: %s", klass->name()->as_C_string()));
++ klass->set_redefinition_flag(Klass::MarkedAsAffected);
++ _affected_klasses->append(klass);
++ return;
++ }
++ }
++
++ // Check secondary supers
++ int cnt = klass->secondary_supers()->length();
++ for (int i = 0; i < cnt; i++) {
++ Klass* secondary = klass->secondary_supers()->at(i);
++ if (secondary->check_redefinition_flag(Klass::MarkedAsAffected)) {
++ RC_TRACE(0x00000001, ("Found affected class: %s", klass->name()->as_C_string()));
++ klass->set_redefinition_flag(Klass::MarkedAsAffected);
++ _affected_klasses->append(klass);
++ return;
++ }
++ }
++}
++
++
++// Searches for all affected classes and performs a sorting such that a supertype is always before a subtype.
++jvmtiError VM_EnhancedRedefineClasses::find_sorted_affected_classes() {
++
++ assert(_affected_klasses, "");
++ for (int i = 0; i < _class_count; i++) {
++ oop mirror = JNIHandles::resolve_non_null(_class_defs[i].klass);
++ instanceKlassHandle klass_handle(Thread::current(), java_lang_Class::as_Klass(mirror));
++ klass_handle->set_redefinition_flag(Klass::MarkedAsAffected);
++ assert(klass_handle->new_version() == NULL, "Must be new class");
++ RC_TRACE(0x00000001, ("Class being reloaded: %s", klass_handle->name()->as_C_string()));
++ }
++
++ // Find classes not directly redefined, but affected by a redefinition (because one of its supertypes is redefined)
++ SystemDictionary::classes_do(VM_EnhancedRedefineClasses::add_affected_klasses);
++ RC_TRACE(0x00000001, ("%d classes affected", _affected_klasses->length()));
++
++ // Sort the affected klasses such that a supertype is always on a smaller array index than its subtype.
++ jvmtiError result = do_topological_class_sorting(_class_defs, _class_count, Thread::current());
++ if (RC_TRACE_ENABLED(0x00000001)) {
++ RC_TRACE(0x00000001, ("Redefine order: "));
++ for (int i = 0; i < _affected_klasses->length(); i++) {
++ RC_TRACE(0x00000001, ("%s", _affected_klasses->at(i)->name()->as_C_string()));
++ }
++ }
++
++ return result;
++}
++
++// Searches for the class bytes of the given class and returns them as a byte array.
++jvmtiError VM_EnhancedRedefineClasses::find_class_bytes(instanceKlassHandle the_class, const unsigned char **class_bytes, jint *class_byte_count, jboolean *not_changed) {
++
++ *not_changed = false;
++
++ // Search for the index in the redefinition array that corresponds to the current class
++ int j;
++ for (j=0; j<_class_count; j++) {
++ oop mirror = JNIHandles::resolve_non_null(_class_defs[j].klass);
++ Klass* the_class_oop = java_lang_Class::as_Klass(mirror);
++ if (the_class_oop == the_class()) {
++ break;
++ }
++ }
++
++ if (j == _class_count) {
++
++ *not_changed = true;
++
++ // Redefine with same bytecodes. This is a class that is only indirectly affected by redefinition,
++ // so the user did not specify a different bytecode for that class.
++
++ if (the_class->get_cached_class_file_bytes() == NULL) {
++ // not cached, we need to reconstitute the class file from VM representation
++ constantPoolHandle constants(Thread::current(), the_class->constants());
++ MonitorLockerEx ml(constants->lock()); // lock constant pool while we query it
++ //ObjectLocker ol(constants, Thread::current()); // lock constant pool while we query it
++
++ JvmtiClassFileReconstituter reconstituter(the_class);
++ if (reconstituter.get_error() != JVMTI_ERROR_NONE) {
++ return reconstituter.get_error();
++ }
++
++ *class_byte_count = (jint)reconstituter.class_file_size();
++ *class_bytes = (unsigned char*)reconstituter.class_file_bytes();
++ } else {
++
++ // it is cached, get it from the cache
++ *class_byte_count = the_class->get_cached_class_file_len();
++ *class_bytes = the_class->get_cached_class_file_bytes();
++ }
++
++ } else {
++
++ // Redefine with bytecodes at index j
++ *class_bytes = _class_defs[j].class_bytes;
++ *class_byte_count = _class_defs[j].class_byte_count;
++ }
++
++ return JVMTI_ERROR_NONE;
++}
++
++// Prologue of the VM operation, called on the Java thread in parallel to normal program execution
++bool VM_EnhancedRedefineClasses::doit_prologue() {
++
++ _revision_number++;
++ RC_TRACE(0x00000001,
++ ("Redefinition with revision number %d started!", _revision_number));
++
++ assert(Thread::current()->is_Java_thread(), "must be Java thread");
++ RC_TIMER_START(_timer_prologue);
++
++ if (!check_arguments()) {
++ RC_TIMER_STOP(_timer_prologue);
++ return false;
++ }
++
++ // We first load new class versions in the prologue, because somewhere down the
++ // call chain it is required that the current thread is a Java thread.
++ _new_classes = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<instanceKlassHandle>(5, true);
++
++ assert(_affected_klasses == NULL, "");
++ _affected_klasses = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<instanceKlassHandle>(_class_count, true);
++
++ _result = load_new_class_versions(Thread::current());
++
++ RC_TRACE(0x00000001,
++ ("Loaded new class versions!"));
++ if (_result != JVMTI_ERROR_NONE) {
++ RC_TRACE(0x00000001,
++ ("error occured: %d!", _result));
++ delete _new_classes;
++ _new_classes = NULL;
++ delete _affected_klasses;
++ _affected_klasses = NULL;
++ RC_TIMER_STOP(_timer_prologue);
++ return false;
++ }
++
++ VM_GC_Operation::doit_prologue();
++ RC_TIMER_STOP(_timer_prologue);
++
++ RC_TRACE(0x00000001, ("doit_prologue finished!"));
++ return true;
++}
++
++// Checks basic properties of the arguments of the redefinition command.
++jvmtiError VM_EnhancedRedefineClasses::check_arguments_error() {
++ if (_class_defs == NULL) return JVMTI_ERROR_NULL_POINTER;
++ for (int i = 0; i < _class_count; i++) {
++ if (_class_defs[i].klass == NULL) return JVMTI_ERROR_INVALID_CLASS;
++ if (_class_defs[i].class_byte_count == 0) return JVMTI_ERROR_INVALID_CLASS_FORMAT;
++ if (_class_defs[i].class_bytes == NULL) return JVMTI_ERROR_NULL_POINTER;
++ }
++ return JVMTI_ERROR_NONE;
++ }
++
++// Returns false and sets an result error code if the redefinition should be aborted.
++bool VM_EnhancedRedefineClasses::check_arguments() {
++ jvmtiError error = check_arguments_error();
++ if (error != JVMTI_ERROR_NONE || _class_count == 0) {
++ _result = error;
++ return false;
++ }
++ return true;
++}
++
++jvmtiError VM_EnhancedRedefineClasses::check_exception() const {
++ Thread* THREAD = Thread::current();
++ if (HAS_PENDING_EXCEPTION) {
++
++ Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
++ RC_TRACE_WITH_THREAD(0x00000002, THREAD, ("parse_stream exception: '%s'", ex_name->as_C_string()));
++ CLEAR_PENDING_EXCEPTION;
++
++ if (ex_name == vmSymbols::java_lang_UnsupportedClassVersionError()) {
++ return JVMTI_ERROR_UNSUPPORTED_VERSION;
++ } else if (ex_name == vmSymbols::java_lang_ClassFormatError()) {
++ return JVMTI_ERROR_INVALID_CLASS_FORMAT;
++ } else if (ex_name == vmSymbols::java_lang_ClassCircularityError()) {
++ return JVMTI_ERROR_CIRCULAR_CLASS_DEFINITION;
++ } else if (ex_name == vmSymbols::java_lang_NoClassDefFoundError()) {
++ // The message will be "XXX (wrong name: YYY)"
++ return JVMTI_ERROR_NAMES_DONT_MATCH;
++ } else if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
++ return JVMTI_ERROR_OUT_OF_MEMORY;
++ } else {
++ // Just in case more exceptions can be thrown..
++ return JVMTI_ERROR_FAILS_VERIFICATION;
++ }
++ }
++
++ return JVMTI_ERROR_NONE;
++}
++
++// Loads all new class versions and stores the InstanceKlass handles in an array.
++jvmtiError VM_EnhancedRedefineClasses::load_new_class_versions(TRAPS) {
++
++ ResourceMark rm(THREAD);
++
++ RC_TRACE(0x00000001,
++ ("loading new class versions (%d)", _class_count));
++
++ // Retrieve an array of all classes that need to be redefined
++ jvmtiError err = find_sorted_affected_classes();
++ if (err != JVMTI_ERROR_NONE) {
++ RC_TRACE(0x00000001,
++ ("Error finding sorted affected classes: %d", (int)err));
++ return err;
++ }
++
++
++ JvmtiThreadState *state = JvmtiThreadState::state_for(JavaThread::current());
++
++ _max_redefinition_flags = Klass::NoRedefinition;
++ jvmtiError result = JVMTI_ERROR_NONE;
++
++ for (int i = 0; i < _affected_klasses->length(); i++) {
++ instanceKlassHandle the_class = _affected_klasses->at(i);
++
++ RC_TRACE(0x00000001,
++ ("Processing affected class %s (%d of %d)",
++ the_class->name()->as_C_string(),
++ i + 1,
++ _affected_klasses->length()));
++
++ the_class->link_class(THREAD);
++ result = check_exception();
++ if (result != JVMTI_ERROR_NONE) break;
++
++ // Find new class bytes
++ const unsigned char* class_bytes;
++ jint class_byte_count;
++ jvmtiError error;
++ jboolean not_changed;
++ if ((error = find_class_bytes(the_class, &class_bytes, &class_byte_count, ¬_changed)) != JVMTI_ERROR_NONE) {
++ RC_TRACE_WITH_THREAD(0x00000002, THREAD,
++ ("Error finding class bytes: %d", (int)error));
++ result = error;
++ break;
++ }
++ assert(class_bytes != NULL && class_byte_count != 0, "Class bytes defined at this point!");
++
++
++ // Set redefined class handle in JvmtiThreadState class.
++ // This redefined class is sent to agent event handler for class file
++ // load hook event.
++ state->set_class_being_redefined(&the_class, _class_load_kind);
++
++ RC_TIMER_STOP(_timer_prologue);
++ RC_TIMER_START(_timer_class_loading);
++
++ // Parse the stream.
++ Handle the_class_loader(THREAD, the_class->class_loader());
++ Handle protection_domain(THREAD, the_class->protection_domain());
++ ClassFileStream st((u1*) class_bytes, class_byte_count, (char *)"__VM_EhnancedRedefineClasses__");
++
++ Klass* klass =
++ SystemDictionary::resolve_from_stream(
++ the_class->name(),
++ the_class_loader,
++ protection_domain,
++ &st,
++ true,
++ the_class,
++ THREAD);
++ instanceKlassHandle new_class(THREAD, klass);
++
++ RC_TIMER_STOP(_timer_class_loading);
++ RC_TIMER_START(_timer_prologue);
++
++ // Clear class_being_redefined just to be sure.
++ state->clear_class_being_redefined();
++
++ result = check_exception();
++ if (result != JVMTI_ERROR_NONE) break;
++
++ not_changed = false;
++
++#ifdef ASSERT
++
++ assert(new_class() != NULL, "Class could not be loaded!");
++ assert(new_class() != the_class(), "must be different");
++ assert(new_class->new_version() == NULL && new_class->old_version() != NULL, "");
++
++
++ Array<Klass*>* k_interfaces = new_class->local_interfaces();
++ for (int j = 0; j < k_interfaces->length(); j++) {
++ assert(k_interfaces->at(j)->is_newest_version(), "just checking");
++ }
++
++ if (!THREAD->is_Compiler_thread()) {
++ RC_TRACE(0x00000001, ("name=%s loader="INTPTR_FORMAT" protection_domain="INTPTR_FORMAT,
++ the_class->name()->as_C_string(),
++ (intptr_t) (oopDesc*) the_class->class_loader(),
++ (intptr_t) (oopDesc*) the_class->protection_domain()));
++ // If we are on the compiler thread, we must not try to resolve a class.
++ Klass* systemLookup = SystemDictionary::resolve_or_null(the_class->name(), the_class->class_loader(), the_class->protection_domain(), THREAD);
++
++ if (systemLookup != NULL) {
++ assert(systemLookup == new_class->old_version(), "Old class must be in system dictionary!");
++ Klass *subklass = new_class()->subklass();
++ while (subklass != NULL) {
++ assert(subklass->new_version() == NULL, "Most recent version of class!");
++ subklass = subklass->next_sibling();
++ }
++ } else {
++ // This can happen for reflection generated classes.. ?
++ CLEAR_PENDING_EXCEPTION;
++ }
++ }
++
++#endif
++
++ if (RC_TRACE_ENABLED(0x00000001)) {
++ if (new_class->layout_helper() != the_class->layout_helper()) {
++ RC_TRACE(0x00000001,
++ ("Instance size change for class %s: new=%d old=%d",
++ new_class->name()->as_C_string(),
++ new_class->layout_helper(),
++ the_class->layout_helper()));
++ }
++ }
++
++ // Set the new version of the class
++ new_class->set_revision_number(_revision_number);
++ new_class->set_redefinition_index(i);
++ the_class->set_new_version(new_class());
++ _new_classes->append(new_class);
++
++ assert(new_class->new_version() == NULL, "");
++
++ int redefinition_flags = Klass::NoRedefinition;
++
++ if (not_changed) {
++ redefinition_flags = Klass::NoRedefinition;
++ } else {
++ redefinition_flags = calculate_redefinition_flags(new_class);
++ if (redefinition_flags >= Klass::RemoveSuperType) {
++ result = JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
++ break;
++ }
++ }
++
++ if (new_class->super() != NULL) {
++ redefinition_flags = redefinition_flags | new_class->super()->redefinition_flags();
++ }
++
++ for (int j = 0; j<new_class->local_interfaces()->length(); j++) {
++ redefinition_flags = redefinition_flags | (new_class->local_interfaces()->at(j))->redefinition_flags();
++ }
++
++ new_class->set_redefinition_flags(redefinition_flags);
++
++ _max_redefinition_flags = _max_redefinition_flags | redefinition_flags;
++
++ if ((redefinition_flags & Klass::ModifyInstances) != 0) {
++ // TODO: Check if watch access flags of static fields are updated correctly.
++ calculate_instance_update_information(_new_classes->at(i)());
++ } else {
++ // Fields were not changed, transfer special flags only
++ assert(new_class->layout_helper() >> 1 == new_class->old_version()->layout_helper() >> 1, "must be equal");
++ assert(new_class->fields()->length() == InstanceKlass::cast(new_class->old_version())->fields()->length(), "must be equal");
++
++ JavaFieldStream old_fs(the_class);
++ JavaFieldStream new_fs(new_class);
++ for (; !old_fs.done() && !new_fs.done(); old_fs.next(), new_fs.next()) {
++ AccessFlags flags = new_fs.access_flags();
++ flags.set_is_field_modification_watched(old_fs.access_flags().is_field_modification_watched());
++ flags.set_is_field_access_watched(old_fs.access_flags().is_field_access_watched());
++ new_fs.set_access_flags(flags);
++ }
++ }
++
++ if (RC_TRACE_ENABLED(0x00000001)) {
++ RC_TRACE(0x00000001,
++ ("Super class is %s", new_class->super()->name()->as_C_string()));
++ }
++
++#ifdef ASSERT
++ assert(new_class->super() == NULL || new_class->super()->new_version() == NULL, "Super klass must be newest version!");
++
++ the_class->vtable()->verify(tty);
++ new_class->vtable()->verify(tty);
++#endif
++
++ if (i == _affected_klasses->length() - 1) {
++ // This was the last class processed => check if additional classes have been loaded in the meantime
++ for (int j = 0; j<_affected_klasses->length(); j++) {
++
++ Klass* initial_klass = _affected_klasses->at(j)();
++ Klass *initial_subklass = initial_klass->subklass();
++ Klass *cur_klass = initial_subklass;
++ while(cur_klass != NULL) {
++
++ if(cur_klass->oop_is_instance() && cur_klass->is_newest_version() && !cur_klass->is_redefining()) {
++ instanceKlassHandle handle(THREAD, cur_klass);
++ if (!_affected_klasses->contains(handle)) {
++
++ int k = i + 1;
++ for (; k<_affected_klasses->length(); k++) {
++ if (_affected_klasses->at(k)->is_subtype_of(cur_klass)) {
++ break;
++ }
++ }
++ _affected_klasses->insert_before(k, handle);
++ RC_TRACE(0x00000001,
++ ("Adding newly loaded class to affected classes: %s", cur_klass->name()->as_C_string()));
++ }
++ }
++
++ cur_klass = cur_klass->next_sibling();
++ }
++ }
++
++ int new_count = _affected_klasses->length() - 1 - i;
++ if (new_count != 0) {
++ RC_TRACE(0x00000001,
++ ("Found new number of affected classes: %d", new_count));
++ }
++ }
++ }
++
++ if (result != JVMTI_ERROR_NONE) {
++ rollback();
++ return result;
++ }
++
++ RC_TIMER_STOP(_timer_prologue);
++ RC_TIMER_START(_timer_class_linking);
++ // Link and verify new classes _after_ all classes have been updated in the system dictionary!
++ for (int i=0; i<_affected_klasses->length(); i++) {
++ instanceKlassHandle the_class = _affected_klasses->at(i);
++ instanceKlassHandle new_class(the_class->new_version());
++
++ RC_TRACE(0x00000001,
++ ("Linking class %d/%d %s", i, _affected_klasses->length(), the_class->name()->as_C_string()));
++ new_class->link_class(THREAD);
++
++ result = check_exception();
++ if (result != JVMTI_ERROR_NONE) break;
++ }
++ RC_TIMER_STOP(_timer_class_linking);
++ RC_TIMER_START(_timer_prologue);
++
++ if (result != JVMTI_ERROR_NONE) {
++ rollback();
++ return result;
++ }
++
++ RC_TRACE(0x00000001, ("All classes loaded!"));
++
++#ifdef ASSERT
++ for (int i=0; i<_affected_klasses->length(); i++) {
++ instanceKlassHandle the_class = _affected_klasses->at(i);
++ assert(the_class->new_version() != NULL, "Must have been redefined");
++ instanceKlassHandle new_version = instanceKlassHandle(THREAD, the_class->new_version());
++ assert(new_version->new_version() == NULL, "Must be newest version");
++
++ if (!(new_version->super() == NULL || new_version->super()->new_version() == NULL)) {
++ new_version()->print();
++ new_version->super()->print();
++ }
++ assert(new_version->super() == NULL || new_version->super()->new_version() == NULL, "Super class must be newest version");
++ }
++
++ SystemDictionary::classes_do(check_class, THREAD);
++
++#endif
++
++ RC_TRACE(0x00000001, ("Finished verification!"));
++ return JVMTI_ERROR_NONE;
++}
++
++int VM_EnhancedRedefineClasses::calculate_redefinition_flags(instanceKlassHandle new_class) {
++
++ int result = Klass::NoRedefinition;
++ RC_TRACE(0x00000001,
++ ("Comparing different class versions of class %s", new_class->name()->as_C_string()));
++
++ assert(new_class->old_version() != NULL, "must have old version");
++ instanceKlassHandle the_class(new_class->old_version());
++
++ // Check whether class is in the error init state.
++ if (the_class->is_in_error_state()) {
++ // TBD #5057930: special error code is needed in 1.6
++ //result = Klass::union_redefinition_level(result, Klass::Invalid);
++ }
++
++ int i;
++
++ //////////////////////////////////////////////////////////////////////////////////////////////////////////
++ // Check superclasses
++ assert(new_class->super() == NULL || new_class->super()->is_newest_version(), "");
++ if (the_class->super() != new_class->super()) {
++ // Super class changed
++ Klass* cur_klass = the_class->super();
++ while (cur_klass != NULL) {
++ if (!new_class->is_subclass_of(cur_klass->newest_version())) {
++ RC_TRACE(0x00000001,
++ ("Removed super class %s", cur_klass->name()->as_C_string()));
++ result = result | Klass::RemoveSuperType | Klass::ModifyInstances | Klass::ModifyClass;
++
++ if (!cur_klass->has_subtype_changed()) {
++ RC_TRACE(0x00000001,
++ ("Subtype changed of class %s", cur_klass->name()->as_C_string()));
++ cur_klass->set_subtype_changed(true);
++ }
++ }
++
++ cur_klass = cur_klass->super();
++ }
++
++ cur_klass = new_class->super();
++ while (cur_klass != NULL) {
++ if (!the_class->is_subclass_of(cur_klass->old_version())) {
++ RC_TRACE(0x00000001,
++ ("Added super class %s", cur_klass->name()->as_C_string()));
++ result = result | Klass::ModifyClass | Klass::ModifyInstances;
++ }
++ cur_klass = cur_klass->super();
++ }
++ }
++
++ //////////////////////////////////////////////////////////////////////////////////////////////////////////
++ // Check interfaces
++
++ // Interfaces removed?
++ Array<Klass*>* old_interfaces = the_class->transitive_interfaces();
++ for (i = 0; i<old_interfaces->length(); i++) {
++ instanceKlassHandle old_interface(old_interfaces->at(i));
++ if (!new_class->implements_interface_any_version(old_interface())) {
++ result = result | Klass::RemoveSuperType | Klass::ModifyClass;
++ RC_TRACE(0x00000001,
++ ("Removed interface %s", old_interface->name()->as_C_string()));
++
++ if (!old_interface->has_subtype_changed()) {
++ RC_TRACE(0x00000001,
++ ("Subtype changed of interface %s", old_interface->name()->as_C_string()));
++ old_interface->set_subtype_changed(true);
++ }
++ }
++ }
++
++ // Interfaces added?
++ Array<Klass*>* new_interfaces = new_class->transitive_interfaces();
++ for (i = 0; i<new_interfaces->length(); i++) {
++ if (!the_class->implements_interface_any_version(new_interfaces->at(i))) {
++ result = result | Klass::ModifyClass;
++ RC_TRACE(0x00000001,
++ ("Added interface %s", new_interfaces->at(i)->name()->as_C_string()));
++ }
++ }
++
++
++ // Check whether class modifiers are the same.
++ jushort old_flags = (jushort) the_class->access_flags().get_flags();
++ jushort new_flags = (jushort) new_class->access_flags().get_flags();
++ if (old_flags != new_flags) {
++ // TODO Can this have any effects?
++ }
++
++ // Check if the number, names, types and order of fields declared in these classes
++ // are the same.
++ JavaFieldStream old_fs(the_class);
++ JavaFieldStream new_fs(new_class);
++ for (; !old_fs.done() && !new_fs.done(); old_fs.next(), new_fs.next()) {
++ // access
++ old_flags = old_fs.access_flags().as_short();
++ new_flags = new_fs.access_flags().as_short();
++ if ((old_flags ^ new_flags) & JVM_RECOGNIZED_FIELD_MODIFIERS) {
++ // TODO can this have any effect?
++ }
++ // offset
++ if (old_fs.offset() != new_fs.offset()) {
++ result = result | Klass::ModifyInstances;
++ }
++ // name and signature
++ Symbol* name_sym1 = the_class->constants()->symbol_at(old_fs.name_index());
++ Symbol* sig_sym1 = the_class->constants()->symbol_at(old_fs.signature_index());
++ Symbol* name_sym2 = new_class->constants()->symbol_at(new_fs.name_index());
++ Symbol* sig_sym2 = new_class->constants()->symbol_at(new_fs.signature_index());
++ if (name_sym1 != name_sym2 || sig_sym1 != sig_sym2) {
++ result = result | Klass::ModifyInstances;
++ }
++ }
++
++ // If both streams aren't done then we have a differing number of
++ // fields.
++ if (!old_fs.done() || !new_fs.done()) {
++ result = result | Klass::ModifyInstances;
++ }
++
++ // Do a parallel walk through the old and new methods. Detect
++ // cases where they match (exist in both), have been added in
++ // the new methods, or have been deleted (exist only in the
++ // old methods). The class file parser places methods in order
++ // by method name, but does not order overloaded methods by
++ // signature. In order to determine what fate befell the methods,
++ // this code places the overloaded new methods that have matching
++ // old methods in the same order as the old methods and places
++ // new overloaded methods at the end of overloaded methods of
++ // that name. The code for this order normalization is adapted
++ // from the algorithm used in InstanceKlass::find_method().
++ // Since we are swapping out of order entries as we find them,
++ // we only have to search forward through the overloaded methods.
++ // Methods which are added and have the same name as an existing
++ // method (but different signature) will be put at the end of
++ // the methods with that name, and the name mismatch code will
++ // handle them.
++ Array<Method*>* k_old_methods(the_class->methods()); // FIXME-isd: handles???
++ Array<Method*>* k_new_methods(new_class->methods());
++ int n_old_methods = k_old_methods->length();
++ int n_new_methods = k_new_methods->length();
++
++ int ni = 0;
++ int oi = 0;
++ while (true) {
++ Method* k_old_method;
++ Method* k_new_method;
++ enum { matched, added, deleted, undetermined } method_was = undetermined;
++
++ if (oi >= n_old_methods) {
++ if (ni >= n_new_methods) {
++ break; // we've looked at everything, done
++ }
++ // New method at the end
++ k_new_method = k_new_methods->at(ni);
++ method_was = added;
++ } else if (ni >= n_new_methods) {
++ // Old method, at the end, is deleted
++ k_old_method = k_old_methods->at(oi);
++ method_was = deleted;
++ } else {
++ // There are more methods in both the old and new lists
++ k_old_method = k_old_methods->at(oi);
++ k_new_method = k_new_methods->at(ni);
++ if (k_old_method->name() != k_new_method->name()) {
++ // Methods are sorted by method name, so a mismatch means added
++ // or deleted
++ if (k_old_method->name()->fast_compare(k_new_method->name()) > 0) {
++ method_was = added;
++ } else {
++ method_was = deleted;
++ }
++ } else if (k_old_method->signature() == k_new_method->signature()) {
++ // Both the name and signature match
++ method_was = matched;
++ } else {
++ // The name matches, but the signature doesn't, which means we have to
++ // search forward through the new overloaded methods.
++ int nj; // outside the loop for post-loop check
++ for (nj = ni + 1; nj < n_new_methods; nj++) {
++ Method* m = k_new_methods->at(nj);
++ if (k_old_method->name() != m->name()) {
++ // reached another method name so no more overloaded methods
++ method_was = deleted;
++ break;
++ }
++ if (k_old_method->signature() == m->signature()) {
++ // found a match so swap the methods
++ k_new_methods->at_put(ni, m);
++ k_new_methods->at_put(nj, k_new_method);
++ k_new_method = m;
++ method_was = matched;
++ break;
++ }
++ }
++
++ if (nj >= n_new_methods) {
++ // reached the end without a match; so method was deleted
++ method_was = deleted;
++ }
++ }
++ }
++
++ switch (method_was) {
++ case matched:
++ // methods match, be sure modifiers do too
++ old_flags = (jushort) k_old_method->access_flags().get_flags();
++ new_flags = (jushort) k_new_method->access_flags().get_flags();
++ if ((old_flags ^ new_flags) & ~(JVM_ACC_NATIVE)) {
++ // TODO Can this have any effects? Probably yes on vtables?
++ result = result | Klass::ModifyClass;
++ }
++ {
++ u2 new_num = k_new_method->method_idnum();
++ u2 old_num = k_old_method->method_idnum();
++ if (new_num != old_num) {
++ Method* idnum_owner = new_class->method_with_idnum(old_num);
++ if (idnum_owner != NULL) {
++ // There is already a method assigned this idnum -- switch them
++ idnum_owner->set_method_idnum(new_num);
++ }
++ k_new_method->set_method_idnum(old_num);
++ RC_TRACE(0x00008000,
++ ("swapping idnum of new and old method %d / %d!", new_num, old_num));
++ }
++ }
++ RC_TRACE(0x00008000, ("Method matched: new: %s [%d] == old: %s [%d]",
++ k_new_method->name_and_sig_as_C_string(), ni,
++ k_old_method->name_and_sig_as_C_string(), oi));
++ // advance to next pair of methods
++ ++oi;
++ ++ni;
++ break;
++ case added:
++ // method added, see if it is OK
++ new_flags = (jushort) k_new_method->access_flags().get_flags();
++ if ((new_flags & JVM_ACC_PRIVATE) == 0
++ // hack: private should be treated as final, but alas
++ || (new_flags & (JVM_ACC_FINAL|JVM_ACC_STATIC)) == 0) {
++ // new methods must be private
++ result = result | Klass::ModifyClass;
++ }
++ {
++ u2 num = new_class->next_method_idnum();
++ if (num == ConstMethod::UNSET_IDNUM) {
++ // cannot add any more methods
++ result = result | Klass::ModifyClass;
++ }
++ u2 new_num = k_new_method->method_idnum();
++ Method* idnum_owner = new_class->method_with_idnum(num);
++ if (idnum_owner != NULL) {
++ // There is already a method assigned this idnum -- switch them
++ idnum_owner->set_method_idnum(new_num);
++ }
++ k_new_method->set_method_idnum(num);
++ }
++ RC_TRACE(0x00008000, ("Method added: new: %s [%d], idnum %d",
++ k_new_method->name_and_sig_as_C_string(), ni, k_new_method->method_idnum()));
++ ++ni; // advance to next new method
++ break;
++ case deleted:
++ // method deleted, see if it is OK
++ old_flags = (jushort) k_old_method->access_flags().get_flags();
++ if ((old_flags & JVM_ACC_PRIVATE) == 0
++ // hack: private should be treated as final, but alas
++ || (old_flags & (JVM_ACC_FINAL|JVM_ACC_STATIC)) == 0
++ ) {
++ // deleted methods must be private
++ result = result | Klass::ModifyClass;
++ }
++ RC_TRACE(0x00008000, ("Method deleted: old: %s [%d]",
++ k_old_method->name_and_sig_as_C_string(), oi));
++ ++oi; // advance to next old method
++ break;
++ default:
++ ShouldNotReachHere();
++ }
++ }
++
++ if (new_class()->size() != new_class->old_version()->size()) {
++ result |= Klass::ModifyClassSize;
++ }
++
++ if (new_class->size_helper() != ((InstanceKlass*)(new_class->old_version()))->size_helper()) {
++ result |= Klass::ModifyInstanceSize;
++ }
++
++ // TODO Check method bodies to be able to return NoChange?
++ return result;
++}
++
++void VM_EnhancedRedefineClasses::calculate_instance_update_information(Klass* new_version) {
++
++ class CalculateFieldUpdates : public FieldClosure {
++
++ private:
++ InstanceKlass* _old_ik;
++ GrowableArray<int> _update_info;
++ int _position;
++ bool _copy_backwards;
++
++ public:
++
++ bool does_copy_backwards() {
++ return _copy_backwards;
++ }
++
++ CalculateFieldUpdates(InstanceKlass* old_ik) :
++ _old_ik(old_ik), _position(instanceOopDesc::base_offset_in_bytes()), _copy_backwards(false) {
++ _update_info.append(_position);
++ _update_info.append(0);
++ }
++
++ GrowableArray<int> &finish() {
++ _update_info.append(0);
++ return _update_info;
++ }
++
++ void do_field(fieldDescriptor* fd) {
++ int alignment = fd->offset() - _position;
++ if (alignment > 0) {
++ // This field was aligned, so we need to make sure that we fill the gap
++ fill(alignment);
++ }
++
++ assert(_position == fd->offset(), "must be correct offset!");
++
++ fieldDescriptor old_fd;
++ if (_old_ik->find_field(fd->name(), fd->signature(), false, &old_fd) != NULL) {
++ // Found field in the old class, copy
++ copy(old_fd.offset(), type2aelembytes(fd->field_type()));
++
++ if (old_fd.offset() < fd->offset()) {
++ _copy_backwards = true;
++ }
++
++ // Transfer special flags
++ fd->set_is_field_modification_watched(old_fd.is_field_modification_watched());
++ fd->set_is_field_access_watched(old_fd.is_field_access_watched());
++ } else {
++ // New field, fill
++ fill(type2aelembytes(fd->field_type()));
++ }
++ }
++
++ private:
++
++ void fill(int size) {
++ if (_update_info.length() > 0 && _update_info.at(_update_info.length() - 1) < 0) {
++ (*_update_info.adr_at(_update_info.length() - 1)) -= size;
++ } else {
++ _update_info.append(-size);
++ }
++ _position += size;
++ }
++
++ void copy(int offset, int size) {
++ int prev_end = -1;
++ if (_update_info.length() > 0 && _update_info.at(_update_info.length() - 1) > 0) {
++ prev_end = _update_info.at(_update_info.length() - 2) + _update_info.at(_update_info.length() - 1);
++ }
++
++ if (prev_end == offset) {
++ (*_update_info.adr_at(_update_info.length() - 2)) += size;
++ } else {
++ _update_info.append(size);
++ _update_info.append(offset);
++ }
++
++ _position += size;
++ }
++ };
++
++ InstanceKlass* ik = InstanceKlass::cast(new_version);
++ InstanceKlass* old_ik = InstanceKlass::cast(new_version->old_version());
++ CalculateFieldUpdates cl(old_ik);
++ ik->do_nonstatic_fields(&cl);
++
++ GrowableArray<int> result = cl.finish();
++ ik->store_update_information(result);
++ ik->set_copying_backwards(cl.does_copy_backwards());
++
++
++ if (RC_TRACE_ENABLED(0x00000001)) {
++ RC_TRACE(0x00000001, ("Instance update information for %s:", new_version->name()->as_C_string()));
++ if (cl.does_copy_backwards()) {
++ RC_TRACE(0x00000001, ("\tDoes copy backwards!"));
++ }
++ for (int i=0; i<result.length(); i++) {
++ int curNum = result.at(i);
++ if (curNum < 0) {
++ RC_TRACE(0x00000001, ("\t%d CLEAN", curNum));
++ } else if (curNum > 0) {
++ RC_TRACE(0x00000001, ("\t%d COPY from %d", curNum, result.at(i + 1)));
++ i++;
++ } else {
++ RC_TRACE(0x00000001, ("\tEND"));
++ }
++ }
++ }
++}
++
++void VM_EnhancedRedefineClasses::rollback() {
++ RC_TRACE(0x00000001, ("Rolling back redefinition!"));
++ SystemDictionary::rollback_redefinition();
++
++ for (int i=0; i<_new_classes->length(); i++) {
++ SystemDictionary::remove_from_hierarchy(_new_classes->at(i));
++ }
++
++ for (int i=0; i<_new_classes->length(); i++) {
++ instanceKlassHandle new_class = _new_classes->at(i);
++ new_class->set_redefining(false);
++ new_class->old_version()->set_new_version(NULL);
++ new_class->set_old_version(NULL);
++ }
++
++}
++
++void VM_EnhancedRedefineClasses::swap_marks(oop first, oop second) {
++ markOop first_mark = first->mark();
++ markOop second_mark = second->mark();
++ first->set_mark(second_mark);
++ second->set_mark(first_mark);
++}
++
++class FieldCopier : public FieldClosure {
++ public:
++ void do_field(fieldDescriptor* fd) {
++ InstanceKlass* cur = InstanceKlass::cast(fd->field_holder());
++ oop cur_oop = cur->java_mirror();
++
++ InstanceKlass* old = InstanceKlass::cast(cur->old_version());
++ oop old_oop = old->java_mirror();
++
++ fieldDescriptor result;
++ bool found = old->find_local_field(fd->name(), fd->signature(), &result);
++ if (found && result.is_static()) {
++ RC_TRACE(0x00000001, ("Copying static field value for field %s old_offset=%d new_offset=%d",
++ fd->name()->as_C_string(), result.offset(), fd->offset()));
++ memcpy(cur_oop->obj_field_addr<HeapWord>(fd->offset()),
++ old_oop->obj_field_addr<HeapWord>(result.offset()),
++ type2aelembytes(fd->field_type()));
++
++ // Static fields may have references to java.lang.Class
++ if (fd->field_type() == T_OBJECT) {
++ oop oop = cur_oop->obj_field(fd->offset());
++ if (oop != NULL && oop->is_instanceMirror()) {
++ Klass* klass = java_lang_Class::as_Klass(oop);
++ if (klass != NULL && klass->oop_is_instance()) {
++ assert(oop == InstanceKlass::cast(klass)->java_mirror(), "just checking");
++ if (klass->new_version() != NULL) {
++ oop = InstanceKlass::cast(klass->new_version())->java_mirror();
++ cur_oop->obj_field_put(fd->offset(), oop);
++ }
++ }
++ }
++ }
++ }
++ }
++};
++
++void VM_EnhancedRedefineClasses::mark_as_scavengable(nmethod* nm) {
++ if (!nm->on_scavenge_root_list()) {
++ CodeCache::add_scavenge_root_nmethod(nm);
++ }
++}
++
++struct StoreBarrier {
++ template <class T> static void oop_store(T* p, oop v) { ::oop_store(p, v); }
++};
++
++struct StoreNoBarrier {
++ template <class T> static void oop_store(T* p, oop v) { oopDesc::encode_store_heap_oop_not_null(p, v); }
++};
++
++template <class S>
++class ChangePointersOopClosure : public ExtendedOopClosure {
++ // import java_lang_invoke_MemberName.*
++ enum {
++ REFERENCE_KIND_SHIFT = java_lang_invoke_MemberName::MN_REFERENCE_KIND_SHIFT,
++ REFERENCE_KIND_MASK = java_lang_invoke_MemberName::MN_REFERENCE_KIND_MASK,
++ };
++
++
++ bool update_member_name(oop obj) {
++ int flags = java_lang_invoke_MemberName::flags(obj);
++ int ref_kind = (flags >> REFERENCE_KIND_SHIFT) & REFERENCE_KIND_MASK;
++ if (MethodHandles::ref_kind_is_method(ref_kind)) {
++ Method* m = (Method*) java_lang_invoke_MemberName::vmtarget(obj);
++ if (m != NULL && !m->method_holder()->is_newest_version()) {
++ // Let's try to re-resolve method
++ InstanceKlass* newest = InstanceKlass::cast(m->method_holder()->newest_version());
++ Method* new_method = newest->find_method(m->name(), m->signature());
++
++ if (new_method != NULL) {
++ // Note: we might set NULL at this point, which should force AbstractMethodError at runtime
++ CallInfo info(new_method, newest);
++ MethodHandles::init_method_MemberName(obj, info, true);
++ } else {
++ java_lang_invoke_MemberName::set_vmtarget(obj, NULL);
++ }
++ }
++ } else if (MethodHandles::ref_kind_is_field(ref_kind)) {
++ Klass* k = (Klass*) java_lang_invoke_MemberName::vmtarget(obj);
++ if (k == NULL) {
++ return false; // Was cleared before, this MemberName is invalid.
++ }
++
++ if (k != NULL && !k->is_newest_version()) {
++ // Let's try to re-resolve field
++ fieldDescriptor fd;
++ int offset = java_lang_invoke_MemberName::vmindex(obj);
++ bool is_static = MethodHandles::ref_kind_is_static(ref_kind);
++ InstanceKlass* ik = InstanceKlass::cast(k);
++ if (ik->find_local_field_from_offset(offset, is_static, &fd)) {
++ InstanceKlass* newest = InstanceKlass::cast(k->newest_version());
++ fieldDescriptor fd_new;
++ if (newest->find_local_field(fd.name(), fd.signature(), &fd_new)) {
++ MethodHandles::init_field_MemberName(obj, fd_new, MethodHandles::ref_kind_is_setter(ref_kind));
++ } else {
++ // Matching field is not found in new version, not much we can do here.
++ // JVM will crash once faulty MH is invoked.
++ // However, to avoid that all DMH's using this faulty MH are cleared (set to NULL)
++ // Eventually, we probably want to replace them with something more meaningful,
++ // like instance throwing NoSuchFieldError or DMH that will resort to dynamic
++ // field resolution (with possibility of type conversion)
++ java_lang_invoke_MemberName::set_vmtarget(obj, NULL);
++ java_lang_invoke_MemberName::set_vmindex(obj, 0);
++ return false;
++ }
++ }
++ }
++ }
++ return true;
++ }
++
++ bool update_direct_method_handle(oop obj) {
++ // Always update member name first.
++ oop mem_name = java_lang_invoke_DirectMethodHandle::member(obj);
++ if (!update_member_name(mem_name)) {
++ return false;
++ }
++
++ // Here we rely on DirectMethodHandle implementation.
++ // The current implementation caches field offset in $StaticAccessor/$Accessor
++ int flags = java_lang_invoke_MemberName::flags(mem_name);
++ int ref_kind = (flags >> REFERENCE_KIND_SHIFT) & REFERENCE_KIND_MASK;
++ if (MethodHandles::ref_kind_is_field(ref_kind)) {
++ // Note: we don't care about staticBase field (which is java.lang.Class)
++ // It should be processed during normal object update.
++ // Update offset in StaticAccessor
++ int offset = java_lang_invoke_MemberName::vmindex(mem_name);
++ if (offset != 0) { // index of 0 means that field no longer exist
++ if (java_lang_invoke_DirectMethodHandle_StaticAccessor::is_instance(obj)) {
++ java_lang_invoke_DirectMethodHandle_StaticAccessor::set_static_offset(obj, offset);
++ } else if (java_lang_invoke_DirectMethodHandle_Accessor::is_instance(obj)) {
++ java_lang_invoke_DirectMethodHandle_Accessor::set_field_offset(obj, offset);
++ }
++ }
++ }
++ return true;
++ }
++
++ // Forward pointers to InstanceKlass and mirror class to new versions
++ template <class T>
++ inline void do_oop_work(T* p) {
++ oop obj = oopDesc::load_decode_heap_oop(p);
++ if (obj == NULL) {
++ return;
++ }
++ if (obj->is_instanceMirror()) {
++ Klass* klass = java_lang_Class::as_Klass(obj);
++ if (klass != NULL && klass->oop_is_instance()) {
++ assert(obj == InstanceKlass::cast(klass)->java_mirror(), "just checking");
++ if (klass->new_version() != NULL) {
++ obj = InstanceKlass::cast(klass->new_version())->java_mirror();
++ S::oop_store(p, obj);
++ }
++ }
++ }
++
++ // JSR 292 support, uptade java.lang.invoke.MemberName instances
++ if (java_lang_invoke_MemberName::is_instance(obj)) {
++ update_member_name(obj);
++ } else if (java_lang_invoke_DirectMethodHandle::is_instance(obj)) {
++ if (!update_direct_method_handle(obj)) {
++ // DMH is no longer valid, replace it with null reference.
++ // See note above. We probably want to replace this with something more meaningful.
++ S::oop_store(p, NULL);
++ }
++ }
++ }
++
++ virtual void do_oop(oop* o) {
++ do_oop_work(o);
++ }
++
++ virtual void do_oop(narrowOop* o) {
++ do_oop_work(o);
++ }
++};
++
++class ChangePointersObjectClosure : public ObjectClosure {
++ private:
++
++ OopClosure *_closure;
++ bool _needs_instance_update;
++ oop _tmp_obj;
++ int _tmp_obj_size;
++
++public:
++ ChangePointersObjectClosure(OopClosure *closure) : _closure(closure), _needs_instance_update(false), _tmp_obj(NULL), _tmp_obj_size(0) {}
++
++ bool needs_instance_update() {
++ return _needs_instance_update;
++ }
++
++ void copy_to_tmp(oop o) {
++ int size = o->size();
++ if (_tmp_obj_size < size) {
++ _tmp_obj_size = size;
++ _tmp_obj = (oop)resource_allocate_bytes(size * HeapWordSize);
++ }
++ Copy::aligned_disjoint_words((HeapWord*)o, (HeapWord*)_tmp_obj, size);
++ }
++
++ virtual void do_object(oop obj) {
++ // FIXME: if (obj->is_instanceKlass()) return;
++ if (obj->is_instanceMirror()) {
++ // static fields may have references to old java.lang.Class instances, update them
++ // at the same time, we don't want to update other oops in the java.lang.Class
++ // Causes SIGSEGV?
++ //instanceMirrorKlass::oop_fields_iterate(obj, _closure);
++ } else {
++ obj->oop_iterate_no_header(_closure);
++ }
++
++ if (obj->klass()->new_version() != NULL) {
++ Klass* new_klass = obj->klass()->new_version();
++ /* FIXME: if (obj->is_perm()) {
++ _needs_instance_update = true;
++ } else */if(new_klass->update_information() != NULL) {
++ int size_diff = obj->size() - obj->size_given_klass(new_klass);
++
++ // Either new size is bigger or gap is to small to be filled
++ if (size_diff < 0 || (size_diff > 0 && (size_t) size_diff < CollectedHeap::min_fill_size())) {
++ // We need an instance update => set back to old klass
++ _needs_instance_update = true;
++ } else {
++ oop src = obj;
++ if (new_klass->is_copying_backwards()) {
++ copy_to_tmp(obj);
++ src = _tmp_obj;
++ }
++ src->set_klass(obj->klass()->new_version());
++ MarkSweep::update_fields(obj, src, new_klass->update_information());
++
++ if (size_diff > 0) {
++ HeapWord* dead_space = ((HeapWord *)obj) + obj->size();
++ CollectedHeap::fill_with_object(dead_space, size_diff);
++ }
++ }
++ } else {
++ obj->set_klass(obj->klass()->new_version());
++ }
++ }
++ }
++};
++
++
++void VM_EnhancedRedefineClasses::doit() {
++
++ Thread *thread = Thread::current();
++
++ assert((_max_redefinition_flags & Klass::RemoveSuperType) == 0, "removing super types not allowed");
++
++ if (UseSharedSpaces) {
++ // Sharing is enabled so we remap the shared readonly space to
++ // shared readwrite, private just in case we need to redefine
++ // a shared class. We do the remap during the doit() phase of
++ // the safepoint to be safer.
++ if (!MetaspaceShared::remap_shared_readonly_as_readwrite()) {
++ RC_TRACE(0x00000001,
++ ("failed to remap shared readonly space to readwrite, private"));
++ _result = JVMTI_ERROR_INTERNAL;
++ return;
++ }
++ }
++
++ RC_TIMER_START(_timer_prepare_redefinition);
++ for (int i = 0; i < _new_classes->length(); i++) {
++ redefine_single_class(_new_classes->at(i), thread);
++ }
++
++ // Deoptimize all compiled code that depends on this class
++ flush_dependent_code(instanceKlassHandle(Thread::current(), (Klass*)NULL), Thread::current());
++
++ // Adjust constantpool caches for all classes
++ // that reference methods of the evolved class.
++ ClearCpoolCacheAndUnpatch clear_cpool_cache(Thread::current());
++ ClassLoaderDataGraph::classes_do(&clear_cpool_cache);
++
++ RC_TIMER_STOP(_timer_prepare_redefinition);
++ RC_TIMER_START(_timer_heap_iteration);
++
++ ChangePointersOopClosure<StoreNoBarrier> oopClosureNoBarrier;
++ ChangePointersOopClosure<StoreBarrier> oopClosure;
++ ChangePointersObjectClosure objectClosure(&oopClosure);
++
++ RC_TRACE(0x00000001, ("Before updating instances"));
++ {
++ // Since we may update oops inside nmethod's code blob to point to java.lang.Class in new generation, we need to
++ // make sure such references are properly recognized by GC. For that, If ScavengeRootsInCode is true, we need to
++ // mark such nmethod's as "scavengable".
++ // For now, mark all nmethod's as scavengable that are not scavengable already
++ if (ScavengeRootsInCode) {
++ CodeCache::nmethods_do(mark_as_scavengable);
++ }
++
++ SharedHeap::heap()->gc_prologue(true);
++ Universe::heap()->object_iterate(&objectClosure);
++ Universe::root_oops_do(&oopClosureNoBarrier);
++ SharedHeap::heap()->gc_epilogue(false);
++ }
++ RC_TRACE(0x00000001, ("After updating instances"));
++
++ for (int i = 0; i < _new_classes->length(); i++) {
++ InstanceKlass* cur = InstanceKlass::cast(_new_classes->at(i)());
++ InstanceKlass* old = InstanceKlass::cast(cur->old_version());
++
++ // Swap marks to have same hashcodes
++ markOop cur_mark = cur->prototype_header();
++ markOop old_mark = old->prototype_header();
++ cur->set_prototype_header(old_mark);
++ old->set_prototype_header(cur_mark);
++
++ //swap_marks(cur, old);
++ swap_marks(cur->java_mirror(), old->java_mirror());
++
++ // Revert pool holder for old version of klass (it was updated by one of ours closure!)
++ old->constants()->set_pool_holder(old);
++
++ Klass* array_klasses = old->array_klasses();
++ if (array_klasses != NULL) {
++ assert(cur->array_klasses() == NULL, "just checking");
++
++ // Transfer the array classes, otherwise we might get cast exceptions when casting array types.
++ // Also, set array klasses element klass.
++ cur->set_array_klasses(array_klasses);
++ ObjArrayKlass::cast(array_klasses)->set_element_klass(cur);
++ ArrayKlass::cast(array_klasses)->set_component_mirror(cur->java_mirror());
++ }
++
++ // Initialize the new class! Special static initialization that does not execute the
++ // static constructor but copies static field values from the old class if name
++ // and signature of a static field match.
++ FieldCopier copier;
++ cur->do_local_static_fields(&copier); // TODO (tw): What about internal static fields??
++ //java_lang_Class::set_klass(old->java_mirror(), cur); // FIXME-isd: is that correct?
++ //FIXME-isd: do we need this: ??? old->set_java_mirror(cur->java_mirror());
++
++ // Transfer init state
++ InstanceKlass::ClassState state = old->init_state();
++ if (state > InstanceKlass::linked) {
++ cur->set_init_state(state);
++ }
++ }
++
++ RC_TIMER_STOP(_timer_heap_iteration);
++ RC_TIMER_START(_timer_redefinition);
++ if (objectClosure.needs_instance_update()) {
++ // Do a full garbage collection to update the instance sizes accordingly
++ RC_TRACE(0x00000001, ("Before performing full GC!"));
++ Universe::set_redefining_gc_run(true);
++ notify_gc_begin(true);
++ Universe::heap()->collect_as_vm_thread(GCCause::_heap_inspection);
++ notify_gc_end();
++ Universe::set_redefining_gc_run(false);
++ RC_TRACE(0x00000001, ("GC done!"));
++ }
++
++ // Unmark Klass*s as "redefining"
++ for (int i=0; i<_new_classes->length(); i++) {
++ Klass* cur_klass = _new_classes->at(i)();
++ InstanceKlass* cur = (InstanceKlass*)cur_klass;
++ cur->set_redefining(false);
++ cur->clear_update_information();
++ }
++
++ // Disable any dependent concurrent compilations
++ SystemDictionary::notice_modification();
++
++ // Update klass pointers
++ SystemDictionary::update_constraints_after_redefinition();
++
++ // Set flag indicating that some invariants are no longer true.
++ // See jvmtiExport.hpp for detailed explanation.
++ JvmtiExport::set_has_redefined_a_class();
++
++ // Clean up caches in the compiler interface and compiler threads
++ ciObjectFactory::resort_shared_ci_metadata();
++
++#ifdef ASSERT
++
++ // Universe::verify();
++ // JNIHandles::verify();
++
++ SystemDictionary::classes_do(check_class, thread);
++#endif
++
++ RC_TIMER_STOP(_timer_redefinition);
++
++ if (TraceRedefineClasses > 0) {
++ tty->flush();
++ }
++}
++
++void VM_EnhancedRedefineClasses::doit_epilogue() {
++
++ RC_TIMER_START(_timer_vm_op_epilogue);
++
++ ResourceMark mark;
++
++ VM_GC_Operation::doit_epilogue();
++ RC_TRACE(0x00000001, ("GC Operation epilogue finished!"));
++
++ // Free the array of scratch classes
++ delete _new_classes;
++ _new_classes = NULL;
++
++ // Free the array of affected classes
++ delete _affected_klasses;
++ _affected_klasses = NULL;
++
++ RC_TRACE(0x00000001, ("Redefinition finished!"));
++
++ RC_TIMER_STOP(_timer_vm_op_epilogue);
++}
++
++bool VM_EnhancedRedefineClasses::is_modifiable_class(oop klass_mirror) {
++ // classes for primitives cannot be redefined
++ if (java_lang_Class::is_primitive(klass_mirror)) {
++ return false;
++ }
++ Klass* klass = java_lang_Class::as_Klass(klass_mirror);
++ // classes for arrays cannot be redefined
++ if (klass == NULL || !klass->oop_is_instance()) {
++ return false;
++ }
++ return true;
++}
++
++#ifdef ASSERT
++
++void VM_EnhancedRedefineClasses::verify_classes(Klass* k_oop_latest, oop initiating_loader, TRAPS) {
++ Klass* k_oop = k_oop_latest;
++ while (k_oop != NULL) {
++
++ instanceKlassHandle k_handle(THREAD, k_oop);
++ Verifier::verify(k_handle, Verifier::ThrowException, true, THREAD);
++ k_oop = k_oop->old_version();
++ }
++}
++
++#endif
++
++// Rewrite faster byte-codes back to their slower equivalent. Undoes rewriting happening in templateTable_xxx.cpp
++// The reason is that once we zero cpool caches, we need to re-resolve all entries again. Faster bytecodes do not
++// do that, they assume that cache entry is resolved already.
++void VM_EnhancedRedefineClasses::unpatch_bytecode(Method* method) {
++ RawBytecodeStream bcs(method);
++ Bytecodes::Code code;
++ Bytecodes::Code java_code;
++ while (!bcs.is_last_bytecode()) {
++ code = bcs.raw_next();
++
++ // dcevm : workaround check _illegal in case of lambda methods etc.
++ // TODO: skip lambda/intrinsic before while loop? (method()->is_method_handle_intrinsic() || method()->is_compiled_lambda_form())
++ if (code == Bytecodes::_illegal) {
++ return;
++ }
++
++ address bcp = bcs.bcp();
++
++ if (code == Bytecodes::_breakpoint) {
++ int bci = method->bci_from(bcp);
++ code = method->orig_bytecode_at(bci);
++ java_code = Bytecodes::java_code(code);
++ if (code != java_code &&
++ (java_code == Bytecodes::_getfield ||
++ java_code == Bytecodes::_putfield ||
++ java_code == Bytecodes::_aload_0)) {
++ // Let breakpoint table handling unpatch bytecode
++ method->set_orig_bytecode_at(bci, java_code);
++ }
++ } else {
++ java_code = Bytecodes::java_code(code);
++ if (code != java_code &&
++ (java_code == Bytecodes::_getfield ||
++ java_code == Bytecodes::_putfield ||
++ java_code == Bytecodes::_aload_0)) {
++ *bcp = java_code;
++ }
++ }
++
++ // Additionally, we need to unpatch bytecode at bcp+1 for fast_xaccess (which would be fast field access)
++ if (code == Bytecodes::_fast_iaccess_0 || code == Bytecodes::_fast_aaccess_0 || code == Bytecodes::_fast_faccess_0) {
++ Bytecodes::Code code2 = Bytecodes::code_or_bp_at(bcp + 1);
++ assert(code2 == Bytecodes::_fast_igetfield ||
++ code2 == Bytecodes::_fast_agetfield ||
++ code2 == Bytecodes::_fast_fgetfield, "");
++ *(bcp + 1) = Bytecodes::java_code(code2);
++ }
++ }
++ }
++
++// Unevolving classes may point to old methods directly
++// from their constant pool caches, itables, and/or vtables. We
++// use the SystemDictionary::classes_do() facility and this helper
++// to fix up these pointers. Additional field offsets and vtable indices
++// in the constant pool cache entries are fixed.
++//
++// Note: We currently don't support updating the vtable in
++// arrayKlassOops. See Open Issues in jvmtiRedefineClasses.hpp.
++void VM_EnhancedRedefineClasses::ClearCpoolCacheAndUnpatch::do_klass(Klass* klass) {
++ if (!klass->oop_is_instance()) {
++ return;
++ }
++ HandleMark hm(_thread);
++ InstanceKlass *ik = InstanceKlass::cast(klass);
++ constantPoolHandle other_cp = constantPoolHandle(ik->constants());
++
++ // Update host klass of anonymous classes (for example, produced by lambdas) to newest version.
++ if (ik->is_anonymous() && !ik->host_klass()->is_newest_version()) {
++ ik->set_host_klass(ik->host_klass()->newest_version());
++ }
++
++ for (int i = 0; i < other_cp->length(); i++) {
++ if (other_cp->tag_at(i).is_klass()) {
++ Klass* klass = other_cp->klass_at(i, _thread);
++ if (klass->new_version() != NULL) {
++ // (DCEVM) TODO: check why/if this is necessary
++ other_cp->klass_at_put(i, klass->new_version());
++ }
++ klass = other_cp->klass_at(i, _thread);
++ assert(klass->new_version() == NULL, "Must be new klass!");
++ }
++ }
++
++ ConstantPoolCache* cp_cache = other_cp->cache();
++ if (cp_cache != NULL) {
++ cp_cache->clear_entries();
++ }
++
++ // If bytecode rewriting is enabled, we also need to unpatch bytecode to force resolution of zeroed entries
++ if (RewriteBytecodes) {
++ ik->methods_do(unpatch_bytecode);
++ }
++}
++
++void VM_EnhancedRedefineClasses::update_jmethod_ids() {
++ for (int j = 0; j < _matching_methods_length; ++j) {
++ Method* old_method = _old_methods->at(_matching_old_methods[j]);
++ jmethodID jmid = old_method->find_jmethod_id_or_null();
++ RC_TRACE(0x00008000, ("matching method %s, jmid %d", old_method->name_and_sig_as_C_string(), *((int *)&jmid)));
++ if (old_method->new_version() != NULL && jmid == NULL) {
++ // (DCEVM) Have to create jmethodID in this case
++ jmid = old_method->jmethod_id();
++ }
++
++ if (jmid != NULL) {
++ // There is a jmethodID, change it to point to the new method
++ methodHandle new_method_h(_new_methods->at(_matching_new_methods[j]));
++ if (old_method->new_version() == NULL) {
++ methodHandle old_method_h(_old_methods->at(_matching_old_methods[j]));
++ jmethodID new_jmethod_id = Method::make_jmethod_id(old_method_h->method_holder()->class_loader_data(), old_method_h());
++ bool result = InstanceKlass::cast(old_method_h->method_holder())->update_jmethod_id(old_method_h(), new_jmethod_id);
++ } else {
++ jmethodID mid = new_method_h->jmethod_id();
++ bool result = InstanceKlass::cast(new_method_h->method_holder())->update_jmethod_id(new_method_h(), jmid);
++ }
++ Method::change_method_associated_with_jmethod_id(jmid, new_method_h());
++ assert(Method::resolve_jmethod_id(jmid) == _new_methods->at(_matching_new_methods[j]), "should be replaced");
++ jmethodID mid = (_new_methods->at(_matching_new_methods[j]))->jmethod_id();
++ //assert(JNIHandles::resolve_non_null((jobject)mid) == new_method_h(), "must match!");
++ }
++ }
++}
++
++
++// Deoptimize all compiled code that depends on this class.
++//
++// If the can_redefine_classes capability is obtained in the onload
++// phase then the compiler has recorded all dependencies from startup.
++// In that case we need only deoptimize and throw away all compiled code
++// that depends on the class.
++//
++// If can_redefine_classes is obtained sometime after the onload
++// phase then the dependency information may be incomplete. In that case
++// the first call to RedefineClasses causes all compiled code to be
++// thrown away. As can_redefine_classes has been obtained then
++// all future compilations will record dependencies so second and
++// subsequent calls to RedefineClasses need only throw away code
++// that depends on the class.
++//
++void VM_EnhancedRedefineClasses::flush_dependent_code(instanceKlassHandle k_h, TRAPS) {
++ assert_locked_or_safepoint(Compile_lock);
++
++ // All dependencies have been recorded from startup or this is a second or
++ // subsequent use of RedefineClasses
++
++ // For now deopt all
++ // (tw) TODO: Improve the dependency system such that we can safely deopt only a subset of the methods
++ if (0 && JvmtiExport::all_dependencies_are_recorded()) {
++ Universe::flush_evol_dependents_on(k_h);
++ } else {
++ CodeCache::mark_all_nmethods_for_deoptimization();
++
++ ResourceMark rm(THREAD);
++ DeoptimizationMarker dm;
++
++ // Deoptimize all activations depending on marked nmethods
++ Deoptimization::deoptimize_dependents();
++
++ // Make the dependent methods not entrant (in VM_Deoptimize they are made zombies)
++ CodeCache::make_marked_nmethods_not_entrant();
++
++ // From now on we know that the dependency information is complete
++ JvmtiExport::set_all_dependencies_are_recorded(true);
++ }
++}
++
++void VM_EnhancedRedefineClasses::compute_added_deleted_matching_methods() {
++ Method* old_method;
++ Method* new_method;
++
++ _matching_old_methods = NEW_RESOURCE_ARRAY(int, _old_methods->length());
++ _matching_new_methods = NEW_RESOURCE_ARRAY(int, _old_methods->length());
++ _added_methods = NEW_RESOURCE_ARRAY(int, _new_methods->length());
++ _deleted_methods = NEW_RESOURCE_ARRAY(int, _old_methods->length());
++
++ _matching_methods_length = 0;
++ _deleted_methods_length = 0;
++ _added_methods_length = 0;
++
++ int nj = 0;
++ int oj = 0;
++ while (true) {
++ if (oj >= _old_methods->length()) {
++ if (nj >= _new_methods->length()) {
++ break; // we've looked at everything, done
++ }
++ // New method at the end
++ new_method = _new_methods->at(nj);
++ _added_methods[_added_methods_length++] = nj;
++ ++nj;
++ } else if (nj >= _new_methods->length()) {
++ // Old method, at the end, is deleted
++ old_method = _old_methods->at(oj);
++ _deleted_methods[_deleted_methods_length++] = oj;
++ ++oj;
++ } else {
++ old_method = _old_methods->at(oj);
++ new_method = _new_methods->at(nj);
++ if (old_method->name() == new_method->name()) {
++ if (old_method->signature() == new_method->signature()) {
++ _matching_old_methods[_matching_methods_length] = oj;//old_method;
++ _matching_new_methods[_matching_methods_length] = nj;//new_method;
++ _matching_methods_length++;
++ ++nj;
++ ++oj;
++ } else {
++ // added overloaded have already been moved to the end,
++ // so this is a deleted overloaded method
++ _deleted_methods[_deleted_methods_length++] = oj;//old_method;
++ ++oj;
++ }
++ } else { // names don't match
++ if (old_method->name()->fast_compare(new_method->name()) > 0) {
++ // new method
++ _added_methods[_added_methods_length++] = nj;//new_method;
++ ++nj;
++ } else {
++ // deleted method
++ _deleted_methods[_deleted_methods_length++] = oj;//old_method;
++ ++oj;
++ }
++ }
++ }
++ }
++ assert(_matching_methods_length + _deleted_methods_length == _old_methods->length(), "sanity");
++ assert(_matching_methods_length + _added_methods_length == _new_methods->length(), "sanity");
++ RC_TRACE(0x00008000, ("Matching methods = %d / deleted methods = %d / added methods = %d",
++ _matching_methods_length, _deleted_methods_length, _added_methods_length));
++}
++
++
++
++// Install the redefinition of a class:
++// - house keeping (flushing breakpoints and caches, deoptimizing
++// dependent compiled code)
++// - adjusting constant pool caches and vtables in other classes
++void VM_EnhancedRedefineClasses::redefine_single_class(instanceKlassHandle the_new_class, TRAPS) {
++
++ ResourceMark rm(THREAD);
++
++ assert(the_new_class->old_version() != NULL, "Must not be null");
++ assert(the_new_class->old_version()->new_version() == the_new_class(), "Must equal");
++
++ instanceKlassHandle the_old_class = instanceKlassHandle(THREAD, the_new_class->old_version());
++
++#ifndef JVMTI_KERNEL
++ // Remove all breakpoints in methods of this class
++ JvmtiBreakpoints& jvmti_breakpoints = JvmtiCurrentBreakpoints::get_jvmti_breakpoints();
++ jvmti_breakpoints.clearall_in_class_at_safepoint(the_old_class());
++#endif // !JVMTI_KERNEL
++
++ /* FIXME
++ if (the_old_class() == Universe::reflect_invoke_cache()->klass()) {
++ // We are redefining java.lang.reflect.Method. Method.invoke() is
++ // cached and users of the cache care about each active version of
++ // the method so we have to track this previous version.
++ // Do this before methods get switched
++ Universe::reflect_invoke_cache()->add_previous_version(
++ the_old_class->method_with_idnum(Universe::reflect_invoke_cache()->method_idnum()));
++ }*/
++
++ _old_methods = the_old_class->methods();
++ _new_methods = the_new_class->methods();
++ compute_added_deleted_matching_methods();
++
++ // track which methods are EMCP for add_previous_version() call below
++
++ // TODO: Check if we need the concept of EMCP?
++ BitMap emcp_methods(_old_methods->length());
++ int emcp_method_count = 0;
++ emcp_methods.clear(); // clears 0..(length() - 1)
++
++ // We need to mark methods as old!!
++ check_methods_and_mark_as_obsolete(&emcp_methods, &emcp_method_count);
++ update_jmethod_ids();
++
++ // TODO:
++ transfer_old_native_function_registrations(the_old_class);
++
++ // JSR-292 support
++
++ // Swap method handles
++ MemberNameTable* mnt = the_old_class->member_names();
++ assert(the_new_class->member_names() == NULL, "");
++ the_new_class->set_member_names(mnt);
++ the_old_class->set_member_names(NULL);
++
++ // FIXME: should we add field MemberName's in this list and process all of them here?
++// if (mnt != NULL) {
++// for (int i = 0; i < mnt->length(); i++) {
++// oop mem_name = mnt->get_member_name(i);
++// if (mem_name != NULL) {
++// Method* method = (Method*) java_lang_invoke_MemberName::vmtarget(mem_name);
++//
++// // Replace the method with matching one from the new class
++// Method* new_method = the_new_class->find_method(method->name(), method->signature());
++// java_lang_invoke_MemberName::set_vmtarget(mem_name, new_method);
++// }
++// }
++// }
++
++#ifdef ASSERT
++
++// Klass* systemLookup1 = SystemDictionary::resolve_or_null(the_old_class->name(), the_old_class->class_loader(), the_old_class->protection_domain(), THREAD);
++// assert(systemLookup1 == the_new_class(), "New class must be in system dictionary!");
++
++ //JNIHandles::verify();
++
++// Klass* systemLookup = SystemDictionary::resolve_or_null(the_old_class->name(), the_old_class->class_loader(), the_old_class->protection_domain(), THREAD);
++
++// assert(systemLookup == the_new_class(), "New class must be in system dictionary!");
++ assert(the_new_class->old_version() != NULL, "Must not be null");
++ assert(the_new_class->old_version()->new_version() == the_new_class(), "Must equal");
++
++ for (int i=0; i<the_new_class->methods()->length(); i++) {
++ assert((the_new_class->methods()->at(i))->method_holder() == the_new_class(), "method holder must match!");
++ }
++
++ // FIXME:
++ //_old_methods->verify();
++ //_new_methods->verify();
++
++ the_new_class->vtable()->verify(tty);
++ the_old_class->vtable()->verify(tty);
++
++#endif
++
++ // increment the classRedefinedCount field in the_class and in any
++ // direct and indirect subclasses of the_class
++ increment_class_counter((InstanceKlass *)the_old_class(), THREAD);
++
++}
++
++
++void VM_EnhancedRedefineClasses::check_methods_and_mark_as_obsolete(BitMap *emcp_methods, int * emcp_method_count_p) {
++ RC_TRACE(0x00000100, ("Checking matching methods for EMCP"));
++ *emcp_method_count_p = 0;
++ int obsolete_count = 0;
++ int old_index = 0;
++ for (int j = 0; j < _matching_methods_length; ++j, ++old_index) {
++ Method* old_method = _old_methods->at(_matching_old_methods[j]);
++ Method* new_method = _new_methods->at(_matching_new_methods[j]);
++ Method* old_array_method;
++
++ // Maintain an old_index into the _old_methods array by skipping
++ // deleted methods
++ while ((old_array_method = _old_methods->at(old_index)) != old_method) {
++ ++old_index;
++ }
++
++ if (MethodComparator::methods_EMCP(old_method, new_method)) {
++ // The EMCP definition from JSR-163 requires the bytecodes to be
++ // the same with the exception of constant pool indices which may
++ // differ. However, the constants referred to by those indices
++ // must be the same.
++ //
++ // We use methods_EMCP() for comparison since constant pool
++ // merging can remove duplicate constant pool entries that were
++ // present in the old method and removed from the rewritten new
++ // method. A faster binary comparison function would consider the
++ // old and new methods to be different when they are actually
++ // EMCP.
++
++ // track which methods are EMCP for add_previous_version() call
++ emcp_methods->set_bit(old_index);
++ (*emcp_method_count_p)++;
++
++ // An EMCP method is _not_ obsolete. An obsolete method has a
++ // different jmethodID than the current method. An EMCP method
++ // has the same jmethodID as the current method. Having the
++ // same jmethodID for all EMCP versions of a method allows for
++ // a consistent view of the EMCP methods regardless of which
++ // EMCP method you happen to have in hand. For example, a
++ // breakpoint set in one EMCP method will work for all EMCP
++ // versions of the method including the current one.
++
++ old_method->set_new_version(new_method);
++ new_method->set_old_version(old_method);
++
++ RC_TRACE(0x00000100, ("Found EMCP method %s", old_method->name_and_sig_as_C_string()));
++
++ // Transfer breakpoints
++ InstanceKlass *ik = InstanceKlass::cast(old_method->method_holder());
++ for (BreakpointInfo* bp = ik->breakpoints(); bp != NULL; bp = bp->next()) {
++ RC_TRACE(0x00000100, ("Checking breakpoint: %d / %d",
++ bp->match(old_method), bp->match(new_method)));
++ if (bp->match(old_method)) {
++ assert(bp->match(new_method), "if old method is method, then new method must match too");
++ RC_TRACE(0x00000100, ("Found a breakpoint in an old EMCP method"));
++ new_method->set_breakpoint(bp->bci());
++ }
++ }
++ } else {
++ // mark obsolete methods as such
++ old_method->set_is_obsolete();
++ obsolete_count++;
++
++ // With tracing we try not to "yack" too much. The position of
++ // this trace assumes there are fewer obsolete methods than
++ // EMCP methods.
++ RC_TRACE(0x00000100, ("mark %s(%s) as obsolete",
++ old_method->name()->as_C_string(),
++ old_method->signature()->as_C_string()));
++ }
++ old_method->set_is_old();
++ }
++ for (int i = 0; i < _deleted_methods_length; ++i) {
++ Method* old_method = _old_methods->at(_deleted_methods[i]);
++
++ //assert(old_method->vtable_index() < 0,
++ // "cannot delete methods with vtable entries");;
++
++ // Mark all deleted methods as old and obsolete
++ old_method->set_is_old();
++ old_method->set_is_obsolete();
++ ++obsolete_count;
++ // With tracing we try not to "yack" too much. The position of
++ // this trace assumes there are fewer obsolete methods than
++ // EMCP methods.
++ RC_TRACE(0x00000100, ("mark deleted %s(%s) as obsolete",
++ old_method->name()->as_C_string(),
++ old_method->signature()->as_C_string()));
++ }
++ //assert((*emcp_method_count_p + obsolete_count) == _old_methods->length(), "sanity check");
++ RC_TRACE(0x00000100, ("EMCP_cnt=%d, obsolete_cnt=%d !",
++ *emcp_method_count_p, obsolete_count));
++}
++
++// Increment the classRedefinedCount field in the specific InstanceKlass
++// and in all direct and indirect subclasses.
++void VM_EnhancedRedefineClasses::increment_class_counter(Klass* klass, TRAPS) {
++ oop class_mirror = klass->java_mirror();
++ int new_count = java_lang_Class::classRedefinedCount(class_mirror) + 1;
++ java_lang_Class::set_classRedefinedCount(class_mirror, new_count);
++ RC_TRACE(0x00000008, ("updated count for class=%s to %d", klass->external_name(), new_count));
++}
++
++#ifndef PRODUCT
++void VM_EnhancedRedefineClasses::check_class(Klass* k_oop, TRAPS) {
++ Klass *k = k_oop;
++ if (k->oop_is_instance()) {
++ HandleMark hm(THREAD);
++ InstanceKlass *ik = (InstanceKlass *) k;
++ assert(ik->is_newest_version(), "must be latest version in system dictionary");
++
++ if (ik->vtable_length() > 0) {
++ ResourceMark rm(THREAD);
++ assert(ik->vtable()->check_no_old_or_obsolete_entries(), "old method found");
++ ik->vtable()->verify(tty, true);
++ }
++ }
++}
++
++#endif
++
++static bool match_second(void* value, Pair<Klass*, Klass*> elem) {
++ return elem.second == value;
++}
++
++jvmtiError VM_EnhancedRedefineClasses::do_topological_class_sorting( const jvmtiClassDefinition *class_defs, int class_count, TRAPS) {
++ ResourceMark mark(THREAD);
++ GrowableArray<Pair<Klass*, Klass*> > links;
++
++ for (int i=0; i<class_count; i++) {
++
++ oop mirror = JNIHandles::resolve_non_null(class_defs[i].klass);
++ instanceKlassHandle the_class(THREAD, java_lang_Class::as_Klass(mirror));
++ Handle the_class_loader(THREAD, the_class->class_loader());
++ Handle protection_domain(THREAD, the_class->protection_domain());
++
++ ClassFileStream st((u1*) class_defs[i].class_bytes,
++ class_defs[i].class_byte_count, (char *)"__VM_EnhancedRedefineClasses__");
++ ClassFileParser cfp(&st);
++
++
++
++ TempNewSymbol parsed_name;
++ GrowableArray<Symbol*>* super_symbols = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<Symbol*>(0, true);
++ cfp.parseClassFile(the_class->name(),
++ the_class->class_loader_data(),
++ protection_domain,
++ the_class, KlassHandle(),
++ NULL,
++ super_symbols,
++ parsed_name,
++ false,
++ THREAD);
++
++ for (int j = 0; j < super_symbols->length(); j++) {
++ Symbol* sym = super_symbols->at(j);
++ Klass* super_klass = SystemDictionary::resolve_or_null(sym, the_class_loader, protection_domain, THREAD);
++ if (super_klass != NULL) {
++ instanceKlassHandle the_super_class(THREAD, super_klass);
++ if (_affected_klasses->contains(the_super_class)) {
++ links.append(Pair<Klass*, Klass*>(super_klass, the_class()));
++ }
++ }
++ }
++ delete super_symbols;
++
++ assert(the_class->check_redefinition_flag(Klass::MarkedAsAffected), "");
++ the_class->clear_redefinition_flag(Klass::MarkedAsAffected);
++ }
++
++ for (int i=0; i < _affected_klasses->length(); i++) {
++ instanceKlassHandle klass = _affected_klasses->at(i);
++
++ if (klass->check_redefinition_flag(Klass::MarkedAsAffected)) {
++ klass->clear_redefinition_flag(Klass::MarkedAsAffected);
++ Klass* superKlass = klass->super();
++ if (_affected_klasses->contains(superKlass)) {
++ links.append(Pair<Klass*, Klass*>(superKlass, klass()));
++ }
++
++ Array<Klass*>* superInterfaces = klass->local_interfaces();
++ for (int j=0; j<superInterfaces->length(); j++) {
++ Klass* interfaceKlass = superInterfaces->at(j);
++ if (_affected_klasses->contains(interfaceKlass)) {
++ links.append(Pair<Klass*, Klass*>(interfaceKlass, klass()));
++ }
++ }
++ }
++ }
++
++ for (int i = 0; i < _affected_klasses->length(); i++) {
++ int j;
++ for (j = i; j < _affected_klasses->length(); j++) {
++ // Search for node with no incoming edges
++ Klass* oop = _affected_klasses->at(j)();
++ int k = links.find(oop, match_second);
++ if (k == -1) break;
++ }
++ if (j == _affected_klasses->length()) {
++ return JVMTI_ERROR_CIRCULAR_CLASS_DEFINITION;
++ }
++
++ // Remove all links from this node
++ Klass* oop = _affected_klasses->at(j)();
++ int k = 0;
++ while (k < links.length()) {
++ if (links.adr_at(k)->first == oop) {
++ links.delete_at(k);
++ } else {
++ k++;
++ }
++ }
++
++ // Swap node
++ instanceKlassHandle tmp = _affected_klasses->at(j);
++ _affected_klasses->at_put(j, _affected_klasses->at(i));
++ _affected_klasses->at_put(i, tmp);
++ }
++
++ return JVMTI_ERROR_NONE;
++}
++
++// This internal class transfers the native function registration from old methods
++// to new methods. It is designed to handle both the simple case of unchanged
++// native methods and the complex cases of native method prefixes being added and/or
++// removed.
++// It expects only to be used during the VM_EnhancedRedefineClasses op (a safepoint).
++//
++// This class is used after the new methods have been installed in "the_class".
++//
++// So, for example, the following must be handled. Where 'm' is a method and
++// a number followed by an underscore is a prefix.
++//
++// Old Name New Name
++// Simple transfer to new method m -> m
++// Add prefix m -> 1_m
++// Remove prefix 1_m -> m
++// Simultaneous add of prefixes m -> 3_2_1_m
++// Simultaneous removal of prefixes 3_2_1_m -> m
++// Simultaneous add and remove 1_m -> 2_m
++// Same, caused by prefix removal only 3_2_1_m -> 3_2_m
++//
++class TransferNativeFunctionRegistration {
++ private:
++ instanceKlassHandle the_class;
++ int prefix_count;
++ char** prefixes;
++
++ // Recursively search the binary tree of possibly prefixed method names.
++ // Iteration could be used if all agents were well behaved. Full tree walk is
++ // more resilent to agents not cleaning up intermediate methods.
++ // Branch at each depth in the binary tree is:
++ // (1) without the prefix.
++ // (2) with the prefix.
++ // where 'prefix' is the prefix at that 'depth' (first prefix, second prefix,...)
++ Method* search_prefix_name_space(int depth, char* name_str, size_t name_len,
++ Symbol* signature) {
++ Symbol* name_symbol = SymbolTable::probe(name_str, (int)name_len);
++ if (name_symbol != NULL) {
++ Method* method = the_class()->new_version()->lookup_method(name_symbol, signature);
++ if (method != NULL) {
++ // Even if prefixed, intermediate methods must exist.
++ if (method->is_native()) {
++ // Wahoo, we found a (possibly prefixed) version of the method, return it.
++ return method;
++ }
++ if (depth < prefix_count) {
++ // Try applying further prefixes (other than this one).
++ method = search_prefix_name_space(depth+1, name_str, name_len, signature);
++ if (method != NULL) {
++ return method; // found
++ }
++
++ // Try adding this prefix to the method name and see if it matches
++ // another method name.
++ char* prefix = prefixes[depth];
++ size_t prefix_len = strlen(prefix);
++ size_t trial_len = name_len + prefix_len;
++ char* trial_name_str = NEW_RESOURCE_ARRAY(char, trial_len + 1);
++ strcpy(trial_name_str, prefix);
++ strcat(trial_name_str, name_str);
++ method = search_prefix_name_space(depth+1, trial_name_str, trial_len,
++ signature);
++ if (method != NULL) {
++ // If found along this branch, it was prefixed, mark as such
++ method->set_is_prefixed_native();
++ return method; // found
++ }
++ }
++ }
++ }
++ return NULL; // This whole branch bore nothing
++ }
++
++ // Return the method name with old prefixes stripped away.
++ char* method_name_without_prefixes(Method* method) {
++ Symbol* name = method->name();
++ char* name_str = name->as_utf8();
++
++ // Old prefixing may be defunct, strip prefixes, if any.
++ for (int i = prefix_count-1; i >= 0; i--) {
++ char* prefix = prefixes[i];
++ size_t prefix_len = strlen(prefix);
++ if (strncmp(prefix, name_str, prefix_len) == 0) {
++ name_str += prefix_len;
++ }
++ }
++ return name_str;
++ }
++
++ // Strip any prefixes off the old native method, then try to find a
++ // (possibly prefixed) new native that matches it.
++ Method* strip_and_search_for_new_native(Method* method) {
++ ResourceMark rm;
++ char* name_str = method_name_without_prefixes(method);
++ return search_prefix_name_space(0, name_str, strlen(name_str),
++ method->signature());
++ }
++
++ public:
++
++ // Construct a native method transfer processor for this class.
++ TransferNativeFunctionRegistration(instanceKlassHandle _the_class) {
++ assert(SafepointSynchronize::is_at_safepoint(), "sanity check");
++
++ the_class = _the_class;
++ prefixes = JvmtiExport::get_all_native_method_prefixes(&prefix_count);
++ }
++
++ // Attempt to transfer any of the old or deleted methods that are native
++ void transfer_registrations(instanceKlassHandle old_klass, int* old_methods, int methods_length) {
++ for (int j = 0; j < methods_length; j++) {
++ Method* old_method = old_klass->methods()->at(old_methods[j]);
++
++ if (old_method->is_native() && old_method->has_native_function()) {
++ Method* new_method = strip_and_search_for_new_native(old_method);
++ if (new_method != NULL) {
++ // Actually set the native function in the new method.
++ // Redefine does not send events (except CFLH), certainly not this
++ // behind the scenes re-registration.
++ new_method->set_native_function(old_method->native_function(),
++ !Method::native_bind_event_is_interesting);
++ }
++ }
++ }
++ }
++};
++
++// Don't lose the association between a native method and its JNI function.
++void VM_EnhancedRedefineClasses::transfer_old_native_function_registrations(instanceKlassHandle old_klass) {
++ TransferNativeFunctionRegistration transfer(old_klass);
++ transfer.transfer_registrations(old_klass, _deleted_methods, _deleted_methods_length);
++ transfer.transfer_registrations(old_klass, _matching_old_methods, _matching_methods_length);
++}
+diff --git a/src/share/vm/prims/jvmtiRedefineClasses2.hpp b/src/share/vm/prims/jvmtiRedefineClasses2.hpp
+new file mode 100644
+index 0000000..09a5842
+--- /dev/null
++++ b/src/share/vm/prims/jvmtiRedefineClasses2.hpp
+@@ -0,0 +1,159 @@
++/*
++ * Copyright (c) 2003, 2011, 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
++ * under the terms of the GNU General Public License version 2 only, as
++ * published by the Free Software Foundation.
++ *
++ * This code is distributed in the hope that it will be useful, but WITHOUT
++ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
++ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
++ * version 2 for more details (a copy is included in the LICENSE file that
++ * accompanied this code).
++ *
++ * You should have received a copy of the GNU General Public License version
++ * 2 along with this work; if not, write to the Free Software Foundation,
++ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
++ *
++ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
++ * or visit www.oracle.com if you need additional information or have any
++ * questions.
++ *
++ */
++
++#ifndef SHARE_VM_PRIMS_JVMTIENHANCEDREDEFINECLASSES_HPP
++#define SHARE_VM_PRIMS_JVMTIENHANCEDREDEFINECLASSES_HPP
++
++#include "jvmtifiles/jvmtiEnv.hpp"
++#include "memory/oopFactory.hpp"
++#include "memory/resourceArea.hpp"
++#include "oops/objArrayKlass.hpp"
++#include "oops/objArrayOop.hpp"
++#include "oops/fieldStreams.hpp"
++#include "prims/jvmtiRedefineClassesTrace.hpp"
++#include "gc_implementation/shared/vmGCOperations.hpp"
++
++// New version that allows arbitrary changes to already loaded classes.
++class VM_EnhancedRedefineClasses: public VM_GC_Operation {
++ private:
++
++ // These static fields are needed by SystemDictionary::classes_do()
++ // facility and the adjust_cpool_cache_and_vtable() helper:
++ static Array<Method*>* _old_methods;
++ static Array<Method*>* _new_methods;
++ static int* _matching_old_methods;
++ static int* _matching_new_methods;
++ static int* _deleted_methods;
++ static int* _added_methods;
++ static int _matching_methods_length;
++ static int _deleted_methods_length;
++ static int _added_methods_length;
++
++ static int _revision_number;
++
++ static GrowableArray<instanceKlassHandle>* _affected_klasses;
++
++ // The instance fields are used to pass information from
++ // doit_prologue() to doit() and doit_epilogue().
++ jint _class_count;
++ const jvmtiClassDefinition *_class_defs; // ptr to _class_count defs
++
++ // This operation is used by both RedefineClasses and
++ // RetransformClasses. Indicate which.
++ JvmtiClassLoadKind _class_load_kind;
++
++ GrowableArray<instanceKlassHandle>* _new_classes;
++ jvmtiError _result;
++ int _max_redefinition_flags;
++
++ // Performance measurement support. These timers do not cover all
++ // the work done for JVM/TI RedefineClasses() but they do cover
++ // the heavy lifting.
++ elapsedTimer _timer_total;
++ elapsedTimer _timer_prologue;
++ elapsedTimer _timer_class_linking;
++ elapsedTimer _timer_class_loading;
++ elapsedTimer _timer_prepare_redefinition;
++ elapsedTimer _timer_heap_iteration;
++ elapsedTimer _timer_redefinition;
++ elapsedTimer _timer_vm_op_epilogue;
++
++ jvmtiError find_sorted_affected_classes( );
++ jvmtiError find_class_bytes(instanceKlassHandle the_class, const unsigned char **class_bytes, jint *class_byte_count, jboolean *not_changed);
++ jvmtiError load_new_class_versions(TRAPS);
++
++ // Figure out which new methods match old methods in name and signature,
++ // which methods have been added, and which are no longer present
++ void compute_added_deleted_matching_methods();
++
++ // Change jmethodIDs to point to the new methods
++ void update_jmethod_ids();
++
++ static void add_affected_klasses( Klass* obj );
++
++ static jvmtiError do_topological_class_sorting(const jvmtiClassDefinition *class_definitions, int class_count, TRAPS);
++
++ // Install the redefinition of a class
++ void redefine_single_class(instanceKlassHandle the_new_class, TRAPS);
++
++ // Increment the classRedefinedCount field in the specific instanceKlass
++ // and in all direct and indirect subclasses.
++ void increment_class_counter(Klass* klass, TRAPS);
++
++
++ void flush_dependent_code(instanceKlassHandle k_h, TRAPS);
++
++ static void check_class(Klass* k_oop,/* oop initiating_loader,*/ TRAPS) PRODUCT_RETURN;
++
++ static void unpatch_bytecode(Method* method);
++
++#ifdef ASSERT
++ static void verify_classes(Klass* k_oop, oop initiating_loader, TRAPS);
++#endif
++
++ int calculate_redefinition_flags(instanceKlassHandle new_version);
++ void calculate_instance_update_information(Klass* new_version);
++ void check_methods_and_mark_as_obsolete(BitMap *emcp_methods, int * emcp_method_count_p);
++ static void mark_as_scavengable(nmethod* nm);
++
++ bool check_arguments();
++ jvmtiError check_arguments_error();
++
++ class ClearCpoolCacheAndUnpatch : public KlassClosure {
++ Thread* _thread;
++ public:
++ ClearCpoolCacheAndUnpatch(Thread* t) : _thread(t) {}
++ void do_klass(Klass* k);
++ };
++
++ public:
++ VM_EnhancedRedefineClasses(jint class_count, const jvmtiClassDefinition *class_defs, JvmtiClassLoadKind class_load_kind);
++ virtual ~VM_EnhancedRedefineClasses();
++
++ bool doit_prologue();
++ void doit();
++ void doit_epilogue();
++ void rollback();
++
++ jvmtiError check_exception() const;
++ VMOp_Type type() const { return VMOp_RedefineClasses; }
++ bool skip_operation() const { return false; }
++ bool allow_nested_vm_operations() const { return true; }
++ jvmtiError check_error() { return _result; }
++
++ // Modifiable test must be shared between IsModifiableClass query
++ // and redefine implementation
++ static bool is_modifiable_class(oop klass_mirror);
++
++ // Utility methods for transferring field access flags
++
++ static void transfer_special_access_flags(JavaFieldStream *from, JavaFieldStream *to);
++ static void transfer_special_access_flags(fieldDescriptor *from, fieldDescriptor *to);
++
++ void transfer_old_native_function_registrations(instanceKlassHandle the_class);
++
++ static void swap_marks(oop first, oop second);
++};
++
++#endif // SHARE_VM_PRIMS_JVMTIENHANCEDREDEFINECLASSES_HPP
+diff --git a/src/share/vm/runtime/reflection.cpp b/src/share/vm/runtime/reflection.cpp
+index e2f282e..d959921 100644
+--- a/src/share/vm/runtime/reflection.cpp
++++ b/src/share/vm/runtime/reflection.cpp
+@@ -520,6 +520,12 @@
+ AccessFlags access,
+ bool classloader_only,
+ bool protected_restriction) {
++
++ // (DCEVM) Decide accessibility based on active version
++ if (current_class != NULL) {
++ current_class = current_class->active_version();
++ }
++
+ // Verify that current_class can access a field of field_class, where that
+ // field's access bits are "access". We assume that we've already verified
+ // that current_class can access field_class.
+diff -r 98b4b0661837 src/share/vm/runtime/mutexLocker.cpp
+--- a/src/share/vm/runtime/mutexLocker.cpp Wed Sep 06 00:35:24 2017 -0700
++++ b/src/share/vm/runtime/mutexLocker.cpp Tue Dec 12 12:59:26 2017 +0100
+@@ -259,7 +259,7 @@
+ }
+ def(Heap_lock , Monitor, nonleaf+1, false);
+ def(JfieldIdCreation_lock , Mutex , nonleaf+1, true ); // jfieldID, Used in VM_Operation
+- def(MemberNameTable_lock , Mutex , nonleaf+1, false); // Used to protect MemberNameTable
++ def(MemberNameTable_lock , Mutex , nonleaf+1, true); // Used to protect MemberNameTable
+
+ def(CompiledIC_lock , Mutex , nonleaf+2, false); // locks VtableStubs_lock, InlineCacheBuffer_lock
+ def(CompileTaskAlloc_lock , Mutex , nonleaf+2, true );
+
projects / dcevm.git / commitdiff