diff -r 000000000000 -r a61af66fc99e src/share/vm/prims/jvmtiRedefineClasses.cpp --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/share/vm/prims/jvmtiRedefineClasses.cpp Sat Dec 01 00:00:00 2007 +0000 @@ -0,0 +1,3398 @@ +/* + * Copyright 2003-2007 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, + * CA 95054 USA or visit www.sun.com if you need additional information or + * have any questions. + * + */ + +# include "incls/_precompiled.incl" +# include "incls/_jvmtiRedefineClasses.cpp.incl" + + +objArrayOop VM_RedefineClasses::_old_methods = NULL; +objArrayOop VM_RedefineClasses::_new_methods = NULL; +methodOop* VM_RedefineClasses::_matching_old_methods = NULL; +methodOop* VM_RedefineClasses::_matching_new_methods = NULL; +methodOop* VM_RedefineClasses::_deleted_methods = NULL; +methodOop* VM_RedefineClasses::_added_methods = NULL; +int VM_RedefineClasses::_matching_methods_length = 0; +int VM_RedefineClasses::_deleted_methods_length = 0; +int VM_RedefineClasses::_added_methods_length = 0; +klassOop VM_RedefineClasses::_the_class_oop = NULL; + + +VM_RedefineClasses::VM_RedefineClasses(jint class_count, + const jvmtiClassDefinition *class_defs, + JvmtiClassLoadKind class_load_kind) { + _class_count = class_count; + _class_defs = class_defs; + _class_load_kind = class_load_kind; + _res = JVMTI_ERROR_NONE; +} + +bool VM_RedefineClasses::doit_prologue() { + if (_class_count == 0) { + _res = JVMTI_ERROR_NONE; + return false; + } + if (_class_defs == NULL) { + _res = JVMTI_ERROR_NULL_POINTER; + return false; + } + for (int i = 0; i < _class_count; i++) { + if (_class_defs[i].klass == NULL) { + _res = JVMTI_ERROR_INVALID_CLASS; + return false; + } + if (_class_defs[i].class_byte_count == 0) { + _res = JVMTI_ERROR_INVALID_CLASS_FORMAT; + return false; + } + if (_class_defs[i].class_bytes == NULL) { + _res = JVMTI_ERROR_NULL_POINTER; + return false; + } + } + + // Start timer after all the sanity checks; not quite accurate, but + // better than adding a bunch of stop() calls. + RC_TIMER_START(_timer_vm_op_prologue); + + // 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. + _res = load_new_class_versions(Thread::current()); + if (_res != JVMTI_ERROR_NONE) { + // Free os::malloc allocated memory in load_new_class_version. + os::free(_scratch_classes); + RC_TIMER_STOP(_timer_vm_op_prologue); + return false; + } + + RC_TIMER_STOP(_timer_vm_op_prologue); + return true; +} + +void VM_RedefineClasses::doit() { + Thread *thread = Thread::current(); + + 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 (!CompactingPermGenGen::remap_shared_readonly_as_readwrite()) { + RC_TRACE_WITH_THREAD(0x00000001, thread, + ("failed to remap shared readonly space to readwrite, private")); + _res = JVMTI_ERROR_INTERNAL; + return; + } + } + + for (int i = 0; i < _class_count; i++) { + redefine_single_class(_class_defs[i].klass, _scratch_classes[i], thread); + } + // Disable any dependent concurrent compilations + SystemDictionary::notice_modification(); + + // Set flag indicating that some invariants are no longer true. + // See jvmtiExport.hpp for detailed explanation. + JvmtiExport::set_has_redefined_a_class(); + +#ifdef ASSERT + SystemDictionary::classes_do(check_class, thread); +#endif +} + +void VM_RedefineClasses::doit_epilogue() { + // Free os::malloc allocated memory. + // The memory allocated in redefine will be free'ed in next VM operation. + os::free(_scratch_classes); + + if (RC_TRACE_ENABLED(0x00000004)) { + // Used to have separate timers for "doit" and "all", but the timer + // overhead skewed the measurements. + jlong doit_time = _timer_rsc_phase1.milliseconds() + + _timer_rsc_phase2.milliseconds(); + jlong all_time = _timer_vm_op_prologue.milliseconds() + doit_time; + + RC_TRACE(0x00000004, ("vm_op: all=" UINT64_FORMAT + " prologue=" UINT64_FORMAT " doit=" UINT64_FORMAT, all_time, + _timer_vm_op_prologue.milliseconds(), doit_time)); + RC_TRACE(0x00000004, + ("redefine_single_class: phase1=" UINT64_FORMAT " phase2=" UINT64_FORMAT, + _timer_rsc_phase1.milliseconds(), _timer_rsc_phase2.milliseconds())); + } +} + +bool VM_RedefineClasses::is_modifiable_class(oop klass_mirror) { + // classes for primitives cannot be redefined + if (java_lang_Class::is_primitive(klass_mirror)) { + return false; + } + klassOop the_class_oop = java_lang_Class::as_klassOop(klass_mirror); + // classes for arrays cannot be redefined + if (the_class_oop == NULL || !Klass::cast(the_class_oop)->oop_is_instance()) { + return false; + } + return true; +} + +// Append the current entry at scratch_i in scratch_cp to *merge_cp_p +// where the end of *merge_cp_p is specified by *merge_cp_length_p. For +// direct CP entries, there is just the current entry to append. For +// indirect and double-indirect CP entries, there are zero or more +// referenced CP entries along with the current entry to append. +// Indirect and double-indirect CP entries are handled by recursive +// calls to append_entry() as needed. The referenced CP entries are +// always appended to *merge_cp_p before the referee CP entry. These +// referenced CP entries may already exist in *merge_cp_p in which case +// there is nothing extra to append and only the current entry is +// appended. +void VM_RedefineClasses::append_entry(constantPoolHandle scratch_cp, + int scratch_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p, + TRAPS) { + + // append is different depending on entry tag type + switch (scratch_cp->tag_at(scratch_i).value()) { + + // The old verifier is implemented outside the VM. It loads classes, + // but does not resolve constant pool entries directly so we never + // see Class entries here with the old verifier. Similarly the old + // verifier does not like Class entries in the input constant pool. + // The split-verifier is implemented in the VM so it can optionally + // and directly resolve constant pool entries to load classes. The + // split-verifier can accept either Class entries or UnresolvedClass + // entries in the input constant pool. We revert the appended copy + // back to UnresolvedClass so that either verifier will be happy + // with the constant pool entry. + case JVM_CONSTANT_Class: + { + // revert the copy to JVM_CONSTANT_UnresolvedClass + (*merge_cp_p)->unresolved_klass_at_put(*merge_cp_length_p, + scratch_cp->klass_name_at(scratch_i)); + + if (scratch_i != *merge_cp_length_p) { + // The new entry in *merge_cp_p is at a different index than + // the new entry in scratch_cp so we need to map the index values. + map_index(scratch_cp, scratch_i, *merge_cp_length_p); + } + (*merge_cp_length_p)++; + } break; + + // these are direct CP entries so they can be directly appended, + // but double and long take two constant pool entries + case JVM_CONSTANT_Double: // fall through + case JVM_CONSTANT_Long: + { + scratch_cp->copy_entry_to(scratch_i, *merge_cp_p, *merge_cp_length_p, + THREAD); + + if (scratch_i != *merge_cp_length_p) { + // The new entry in *merge_cp_p is at a different index than + // the new entry in scratch_cp so we need to map the index values. + map_index(scratch_cp, scratch_i, *merge_cp_length_p); + } + (*merge_cp_length_p) += 2; + } break; + + // these are direct CP entries so they can be directly appended + case JVM_CONSTANT_Float: // fall through + case JVM_CONSTANT_Integer: // fall through + case JVM_CONSTANT_Utf8: // fall through + + // This was an indirect CP entry, but it has been changed into + // an interned string so this entry can be directly appended. + case JVM_CONSTANT_String: // fall through + + // These were indirect CP entries, but they have been changed into + // symbolOops so these entries can be directly appended. + case JVM_CONSTANT_UnresolvedClass: // fall through + case JVM_CONSTANT_UnresolvedString: + { + scratch_cp->copy_entry_to(scratch_i, *merge_cp_p, *merge_cp_length_p, + THREAD); + + if (scratch_i != *merge_cp_length_p) { + // The new entry in *merge_cp_p is at a different index than + // the new entry in scratch_cp so we need to map the index values. + map_index(scratch_cp, scratch_i, *merge_cp_length_p); + } + (*merge_cp_length_p)++; + } break; + + // this is an indirect CP entry so it needs special handling + case JVM_CONSTANT_NameAndType: + { + int name_ref_i = scratch_cp->name_ref_index_at(scratch_i); + int new_name_ref_i = 0; + bool match = (name_ref_i < *merge_cp_length_p) && + scratch_cp->compare_entry_to(name_ref_i, *merge_cp_p, name_ref_i, + THREAD); + if (!match) { + // forward reference in *merge_cp_p or not a direct match + + int found_i = scratch_cp->find_matching_entry(name_ref_i, *merge_cp_p, + THREAD); + if (found_i != 0) { + guarantee(found_i != name_ref_i, + "compare_entry_to() and find_matching_entry() do not agree"); + + // Found a matching entry somewhere else in *merge_cp_p so + // just need a mapping entry. + new_name_ref_i = found_i; + map_index(scratch_cp, name_ref_i, found_i); + } else { + // no match found so we have to append this entry to *merge_cp_p + append_entry(scratch_cp, name_ref_i, merge_cp_p, merge_cp_length_p, + THREAD); + // The above call to append_entry() can only append one entry + // so the post call query of *merge_cp_length_p is only for + // the sake of consistency. + new_name_ref_i = *merge_cp_length_p - 1; + } + } + + int signature_ref_i = scratch_cp->signature_ref_index_at(scratch_i); + int new_signature_ref_i = 0; + match = (signature_ref_i < *merge_cp_length_p) && + scratch_cp->compare_entry_to(signature_ref_i, *merge_cp_p, + signature_ref_i, THREAD); + if (!match) { + // forward reference in *merge_cp_p or not a direct match + + int found_i = scratch_cp->find_matching_entry(signature_ref_i, + *merge_cp_p, THREAD); + if (found_i != 0) { + guarantee(found_i != signature_ref_i, + "compare_entry_to() and find_matching_entry() do not agree"); + + // Found a matching entry somewhere else in *merge_cp_p so + // just need a mapping entry. + new_signature_ref_i = found_i; + map_index(scratch_cp, signature_ref_i, found_i); + } else { + // no match found so we have to append this entry to *merge_cp_p + append_entry(scratch_cp, signature_ref_i, merge_cp_p, + merge_cp_length_p, THREAD); + // The above call to append_entry() can only append one entry + // so the post call query of *merge_cp_length_p is only for + // the sake of consistency. + new_signature_ref_i = *merge_cp_length_p - 1; + } + } + + // If the referenced entries already exist in *merge_cp_p, then + // both new_name_ref_i and new_signature_ref_i will both be 0. + // In that case, all we are appending is the current entry. + if (new_name_ref_i == 0) { + new_name_ref_i = name_ref_i; + } else { + RC_TRACE(0x00080000, + ("NameAndType entry@%d name_ref_index change: %d to %d", + *merge_cp_length_p, name_ref_i, new_name_ref_i)); + } + if (new_signature_ref_i == 0) { + new_signature_ref_i = signature_ref_i; + } else { + RC_TRACE(0x00080000, + ("NameAndType entry@%d signature_ref_index change: %d to %d", + *merge_cp_length_p, signature_ref_i, new_signature_ref_i)); + } + + (*merge_cp_p)->name_and_type_at_put(*merge_cp_length_p, + new_name_ref_i, new_signature_ref_i); + if (scratch_i != *merge_cp_length_p) { + // The new entry in *merge_cp_p is at a different index than + // the new entry in scratch_cp so we need to map the index values. + map_index(scratch_cp, scratch_i, *merge_cp_length_p); + } + (*merge_cp_length_p)++; + } break; + + // this is a double-indirect CP entry so it needs special handling + case JVM_CONSTANT_Fieldref: // fall through + case JVM_CONSTANT_InterfaceMethodref: // fall through + case JVM_CONSTANT_Methodref: + { + int klass_ref_i = scratch_cp->uncached_klass_ref_index_at(scratch_i); + int new_klass_ref_i = 0; + bool match = (klass_ref_i < *merge_cp_length_p) && + scratch_cp->compare_entry_to(klass_ref_i, *merge_cp_p, klass_ref_i, + THREAD); + if (!match) { + // forward reference in *merge_cp_p or not a direct match + + int found_i = scratch_cp->find_matching_entry(klass_ref_i, *merge_cp_p, + THREAD); + if (found_i != 0) { + guarantee(found_i != klass_ref_i, + "compare_entry_to() and find_matching_entry() do not agree"); + + // Found a matching entry somewhere else in *merge_cp_p so + // just need a mapping entry. + new_klass_ref_i = found_i; + map_index(scratch_cp, klass_ref_i, found_i); + } else { + // no match found so we have to append this entry to *merge_cp_p + append_entry(scratch_cp, klass_ref_i, merge_cp_p, merge_cp_length_p, + THREAD); + // The above call to append_entry() can only append one entry + // so the post call query of *merge_cp_length_p is only for + // the sake of consistency. Without the optimization where we + // use JVM_CONSTANT_UnresolvedClass, then up to two entries + // could be appended. + new_klass_ref_i = *merge_cp_length_p - 1; + } + } + + int name_and_type_ref_i = + scratch_cp->uncached_name_and_type_ref_index_at(scratch_i); + int new_name_and_type_ref_i = 0; + match = (name_and_type_ref_i < *merge_cp_length_p) && + scratch_cp->compare_entry_to(name_and_type_ref_i, *merge_cp_p, + name_and_type_ref_i, THREAD); + if (!match) { + // forward reference in *merge_cp_p or not a direct match + + int found_i = scratch_cp->find_matching_entry(name_and_type_ref_i, + *merge_cp_p, THREAD); + if (found_i != 0) { + guarantee(found_i != name_and_type_ref_i, + "compare_entry_to() and find_matching_entry() do not agree"); + + // Found a matching entry somewhere else in *merge_cp_p so + // just need a mapping entry. + new_name_and_type_ref_i = found_i; + map_index(scratch_cp, name_and_type_ref_i, found_i); + } else { + // no match found so we have to append this entry to *merge_cp_p + append_entry(scratch_cp, name_and_type_ref_i, merge_cp_p, + merge_cp_length_p, THREAD); + // The above call to append_entry() can append more than + // one entry so the post call query of *merge_cp_length_p + // is required in order to get the right index for the + // JVM_CONSTANT_NameAndType entry. + new_name_and_type_ref_i = *merge_cp_length_p - 1; + } + } + + // If the referenced entries already exist in *merge_cp_p, then + // both new_klass_ref_i and new_name_and_type_ref_i will both be + // 0. In that case, all we are appending is the current entry. + if (new_klass_ref_i == 0) { + new_klass_ref_i = klass_ref_i; + } + if (new_name_and_type_ref_i == 0) { + new_name_and_type_ref_i = name_and_type_ref_i; + } + + const char *entry_name; + switch (scratch_cp->tag_at(scratch_i).value()) { + case JVM_CONSTANT_Fieldref: + entry_name = "Fieldref"; + (*merge_cp_p)->field_at_put(*merge_cp_length_p, new_klass_ref_i, + new_name_and_type_ref_i); + break; + case JVM_CONSTANT_InterfaceMethodref: + entry_name = "IFMethodref"; + (*merge_cp_p)->interface_method_at_put(*merge_cp_length_p, + new_klass_ref_i, new_name_and_type_ref_i); + break; + case JVM_CONSTANT_Methodref: + entry_name = "Methodref"; + (*merge_cp_p)->method_at_put(*merge_cp_length_p, new_klass_ref_i, + new_name_and_type_ref_i); + break; + default: + guarantee(false, "bad switch"); + break; + } + + if (klass_ref_i != new_klass_ref_i) { + RC_TRACE(0x00080000, ("%s entry@%d class_index changed: %d to %d", + entry_name, *merge_cp_length_p, klass_ref_i, new_klass_ref_i)); + } + if (name_and_type_ref_i != new_name_and_type_ref_i) { + RC_TRACE(0x00080000, + ("%s entry@%d name_and_type_index changed: %d to %d", + entry_name, *merge_cp_length_p, name_and_type_ref_i, + new_name_and_type_ref_i)); + } + + if (scratch_i != *merge_cp_length_p) { + // The new entry in *merge_cp_p is at a different index than + // the new entry in scratch_cp so we need to map the index values. + map_index(scratch_cp, scratch_i, *merge_cp_length_p); + } + (*merge_cp_length_p)++; + } break; + + // At this stage, Class or UnresolvedClass could be here, but not + // ClassIndex + case JVM_CONSTANT_ClassIndex: // fall through + + // Invalid is used as the tag for the second constant pool entry + // occupied by JVM_CONSTANT_Double or JVM_CONSTANT_Long. It should + // not be seen by itself. + case JVM_CONSTANT_Invalid: // fall through + + // At this stage, String or UnresolvedString could be here, but not + // StringIndex + case JVM_CONSTANT_StringIndex: // fall through + + // At this stage JVM_CONSTANT_UnresolvedClassInError should not be + // here + case JVM_CONSTANT_UnresolvedClassInError: // fall through + + default: + { + // leave a breadcrumb + jbyte bad_value = scratch_cp->tag_at(scratch_i).value(); + ShouldNotReachHere(); + } break; + } // end switch tag value +} // end append_entry() + + +void VM_RedefineClasses::swap_all_method_annotations(int i, int j, instanceKlassHandle scratch_class) { + typeArrayOop save; + + save = scratch_class->get_method_annotations_of(i); + scratch_class->set_method_annotations_of(i, scratch_class->get_method_annotations_of(j)); + scratch_class->set_method_annotations_of(j, save); + + save = scratch_class->get_method_parameter_annotations_of(i); + scratch_class->set_method_parameter_annotations_of(i, scratch_class->get_method_parameter_annotations_of(j)); + scratch_class->set_method_parameter_annotations_of(j, save); + + save = scratch_class->get_method_default_annotations_of(i); + scratch_class->set_method_default_annotations_of(i, scratch_class->get_method_default_annotations_of(j)); + scratch_class->set_method_default_annotations_of(j, save); +} + + +jvmtiError VM_RedefineClasses::compare_and_normalize_class_versions( + instanceKlassHandle the_class, + instanceKlassHandle scratch_class) { + int i; + + // Check superclasses, or rather their names, since superclasses themselves can be + // requested to replace. + // Check for NULL superclass first since this might be java.lang.Object + if (the_class->super() != scratch_class->super() && + (the_class->super() == NULL || scratch_class->super() == NULL || + Klass::cast(the_class->super())->name() != + Klass::cast(scratch_class->super())->name())) { + return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED; + } + + // Check if the number, names and order of directly implemented interfaces are the same. + // I think in principle we should just check if the sets of names of directly implemented + // interfaces are the same, i.e. the order of declaration (which, however, if changed in the + // .java file, also changes in .class file) should not matter. However, comparing sets is + // technically a bit more difficult, and, more importantly, I am not sure at present that the + // order of interfaces does not matter on the implementation level, i.e. that the VM does not + // rely on it somewhere. + objArrayOop k_interfaces = the_class->local_interfaces(); + objArrayOop k_new_interfaces = scratch_class->local_interfaces(); + int n_intfs = k_interfaces->length(); + if (n_intfs != k_new_interfaces->length()) { + return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED; + } + for (i = 0; i < n_intfs; i++) { + if (Klass::cast((klassOop) k_interfaces->obj_at(i))->name() != + Klass::cast((klassOop) k_new_interfaces->obj_at(i))->name()) { + return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED; + } + } + + // 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 + return JVMTI_ERROR_INVALID_CLASS; + } + + // Check whether class modifiers are the same. + jushort old_flags = (jushort) the_class->access_flags().get_flags(); + jushort new_flags = (jushort) scratch_class->access_flags().get_flags(); + if (old_flags != new_flags) { + return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_MODIFIERS_CHANGED; + } + + // Check if the number, names, types and order of fields declared in these classes + // are the same. + typeArrayOop k_old_fields = the_class->fields(); + typeArrayOop k_new_fields = scratch_class->fields(); + int n_fields = k_old_fields->length(); + if (n_fields != k_new_fields->length()) { + return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED; + } + + for (i = 0; i < n_fields; i += instanceKlass::next_offset) { + // access + old_flags = k_old_fields->ushort_at(i + instanceKlass::access_flags_offset); + new_flags = k_new_fields->ushort_at(i + instanceKlass::access_flags_offset); + if ((old_flags ^ new_flags) & JVM_RECOGNIZED_FIELD_MODIFIERS) { + return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED; + } + // offset + if (k_old_fields->short_at(i + instanceKlass::low_offset) != + k_new_fields->short_at(i + instanceKlass::low_offset) || + k_old_fields->short_at(i + instanceKlass::high_offset) != + k_new_fields->short_at(i + instanceKlass::high_offset)) { + return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED; + } + // name and signature + jshort name_index = k_old_fields->short_at(i + instanceKlass::name_index_offset); + jshort sig_index = k_old_fields->short_at(i +instanceKlass::signature_index_offset); + symbolOop name_sym1 = the_class->constants()->symbol_at(name_index); + symbolOop sig_sym1 = the_class->constants()->symbol_at(sig_index); + name_index = k_new_fields->short_at(i + instanceKlass::name_index_offset); + sig_index = k_new_fields->short_at(i + instanceKlass::signature_index_offset); + symbolOop name_sym2 = scratch_class->constants()->symbol_at(name_index); + symbolOop sig_sym2 = scratch_class->constants()->symbol_at(sig_index); + if (name_sym1 != name_sym2 || sig_sym1 != sig_sym2) { + return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED; + } + } + + // 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. + objArrayHandle k_old_methods(the_class->methods()); + objArrayHandle k_new_methods(scratch_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) { + methodOop k_old_method; + methodOop 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 = (methodOop) k_new_methods->obj_at(ni); + method_was = added; + } else if (ni >= n_new_methods) { + // Old method, at the end, is deleted + k_old_method = (methodOop) k_old_methods->obj_at(oi); + method_was = deleted; + } else { + // There are more methods in both the old and new lists + k_old_method = (methodOop) k_old_methods->obj_at(oi); + k_new_method = (methodOop) k_new_methods->obj_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++) { + methodOop m = (methodOop)k_new_methods->obj_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->obj_at_put(ni, m); + k_new_methods->obj_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)) { + return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_MODIFIERS_CHANGED; + } + { + u2 new_num = k_new_method->method_idnum(); + u2 old_num = k_old_method->method_idnum(); + if (new_num != old_num) { + methodOop idnum_owner = scratch_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); + swap_all_method_annotations(old_num, new_num, scratch_class); + } + } + 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 + return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED; + } + { + u2 num = the_class->next_method_idnum(); + if (num == constMethodOopDesc::UNSET_IDNUM) { + // cannot add any more methods + return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED; + } + u2 new_num = k_new_method->method_idnum(); + methodOop idnum_owner = scratch_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); + swap_all_method_annotations(new_num, num, scratch_class); + } + RC_TRACE(0x00008000, ("Method added: new: %s [%d]", + k_new_method->name_and_sig_as_C_string(), ni)); + ++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 + return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_DELETED; + } + 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(); + } + } + + return JVMTI_ERROR_NONE; +} + + +// Find new constant pool index value for old constant pool index value +// by seaching the index map. Returns zero (0) if there is no mapped +// value for the old constant pool index. +int VM_RedefineClasses::find_new_index(int old_index) { + if (_index_map_count == 0) { + // map is empty so nothing can be found + return 0; + } + + if (old_index < 1 || old_index >= _index_map_p->length()) { + // The old_index is out of range so it is not mapped. This should + // not happen in regular constant pool merging use, but it can + // happen if a corrupt annotation is processed. + return 0; + } + + int value = _index_map_p->at(old_index); + if (value == -1) { + // the old_index is not mapped + return 0; + } + + return value; +} // end find_new_index() + + +// Returns true if the current mismatch is due to a resolved/unresolved +// class pair. Otherwise, returns false. +bool VM_RedefineClasses::is_unresolved_class_mismatch(constantPoolHandle cp1, + int index1, constantPoolHandle cp2, int index2) { + + jbyte t1 = cp1->tag_at(index1).value(); + if (t1 != JVM_CONSTANT_Class && t1 != JVM_CONSTANT_UnresolvedClass) { + return false; // wrong entry type; not our special case + } + + jbyte t2 = cp2->tag_at(index2).value(); + if (t2 != JVM_CONSTANT_Class && t2 != JVM_CONSTANT_UnresolvedClass) { + return false; // wrong entry type; not our special case + } + + if (t1 == t2) { + return false; // not a mismatch; not our special case + } + + char *s1 = cp1->klass_name_at(index1)->as_C_string(); + char *s2 = cp2->klass_name_at(index2)->as_C_string(); + if (strcmp(s1, s2) != 0) { + return false; // strings don't match; not our special case + } + + return true; // made it through the gauntlet; this is our special case +} // end is_unresolved_class_mismatch() + + +// Returns true if the current mismatch is due to a resolved/unresolved +// string pair. Otherwise, returns false. +bool VM_RedefineClasses::is_unresolved_string_mismatch(constantPoolHandle cp1, + int index1, constantPoolHandle cp2, int index2) { + + jbyte t1 = cp1->tag_at(index1).value(); + if (t1 != JVM_CONSTANT_String && t1 != JVM_CONSTANT_UnresolvedString) { + return false; // wrong entry type; not our special case + } + + jbyte t2 = cp2->tag_at(index2).value(); + if (t2 != JVM_CONSTANT_String && t2 != JVM_CONSTANT_UnresolvedString) { + return false; // wrong entry type; not our special case + } + + if (t1 == t2) { + return false; // not a mismatch; not our special case + } + + char *s1 = cp1->string_at_noresolve(index1); + char *s2 = cp2->string_at_noresolve(index2); + if (strcmp(s1, s2) != 0) { + return false; // strings don't match; not our special case + } + + return true; // made it through the gauntlet; this is our special case +} // end is_unresolved_string_mismatch() + + +jvmtiError VM_RedefineClasses::load_new_class_versions(TRAPS) { + // For consistency allocate memory using os::malloc wrapper. + _scratch_classes = (instanceKlassHandle *) + os::malloc(sizeof(instanceKlassHandle) * _class_count); + if (_scratch_classes == NULL) { + return JVMTI_ERROR_OUT_OF_MEMORY; + } + + ResourceMark rm(THREAD); + + JvmtiThreadState *state = JvmtiThreadState::state_for(JavaThread::current()); + for (int i = 0; i < _class_count; i++) { + oop mirror = JNIHandles::resolve_non_null(_class_defs[i].klass); + // classes for primitives cannot be redefined + if (!is_modifiable_class(mirror)) { + return JVMTI_ERROR_UNMODIFIABLE_CLASS; + } + klassOop the_class_oop = java_lang_Class::as_klassOop(mirror); + instanceKlassHandle the_class = instanceKlassHandle(THREAD, the_class_oop); + symbolHandle the_class_sym = symbolHandle(THREAD, the_class->name()); + + // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark + RC_TRACE_WITH_THREAD(0x00000001, THREAD, + ("loading name=%s (avail_mem=" UINT64_FORMAT "K)", + the_class->external_name(), os::available_memory() >> 10)); + + ClassFileStream st((u1*) _class_defs[i].class_bytes, + _class_defs[i].class_byte_count, (char *)"__VM_RedefineClasses__"); + + // Parse the stream. + Handle the_class_loader(THREAD, the_class->class_loader()); + Handle protection_domain(THREAD, the_class->protection_domain()); + // 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); + + klassOop k = SystemDictionary::parse_stream(the_class_sym, + the_class_loader, + protection_domain, + &st, + THREAD); + // Clear class_being_redefined just to be sure. + state->clear_class_being_redefined(); + + // TODO: if this is retransform, and nothing changed we can skip it + + instanceKlassHandle scratch_class (THREAD, k); + + if (HAS_PENDING_EXCEPTION) { + symbolOop ex_name = PENDING_EXCEPTION->klass()->klass_part()->name(); + // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark + 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; + } + } + + // Ensure class is linked before redefine + if (!the_class->is_linked()) { + the_class->link_class(THREAD); + if (HAS_PENDING_EXCEPTION) { + symbolOop ex_name = PENDING_EXCEPTION->klass()->klass_part()->name(); + // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark + RC_TRACE_WITH_THREAD(0x00000002, THREAD, ("link_class exception: '%s'", + ex_name->as_C_string())); + CLEAR_PENDING_EXCEPTION; + if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { + return JVMTI_ERROR_OUT_OF_MEMORY; + } else { + return JVMTI_ERROR_INTERNAL; + } + } + } + + // Do the validity checks in compare_and_normalize_class_versions() + // before verifying the byte codes. By doing these checks first, we + // limit the number of functions that require redirection from + // the_class to scratch_class. In particular, we don't have to + // modify JNI GetSuperclass() and thus won't change its performance. + jvmtiError res = compare_and_normalize_class_versions(the_class, + scratch_class); + if (res != JVMTI_ERROR_NONE) { + return res; + } + + // verify what the caller passed us + { + // The bug 6214132 caused the verification to fail. + // Information about the_class and scratch_class is temporarily + // recorded into jvmtiThreadState. This data is used to redirect + // the_class to scratch_class in the JVM_* functions called by the + // verifier. Please, refer to jvmtiThreadState.hpp for the detailed + // description. + RedefineVerifyMark rvm(&the_class, &scratch_class, state); + Verifier::verify( + scratch_class, Verifier::ThrowException, THREAD); + } + + if (HAS_PENDING_EXCEPTION) { + symbolOop ex_name = PENDING_EXCEPTION->klass()->klass_part()->name(); + // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark + RC_TRACE_WITH_THREAD(0x00000002, THREAD, + ("verify_byte_codes exception: '%s'", ex_name->as_C_string())); + CLEAR_PENDING_EXCEPTION; + if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { + return JVMTI_ERROR_OUT_OF_MEMORY; + } else { + // tell the caller the bytecodes are bad + return JVMTI_ERROR_FAILS_VERIFICATION; + } + } + + res = merge_cp_and_rewrite(the_class, scratch_class, THREAD); + if (res != JVMTI_ERROR_NONE) { + return res; + } + + if (VerifyMergedCPBytecodes) { + // verify what we have done during constant pool merging + { + RedefineVerifyMark rvm(&the_class, &scratch_class, state); + Verifier::verify(scratch_class, Verifier::ThrowException, THREAD); + } + + if (HAS_PENDING_EXCEPTION) { + symbolOop ex_name = PENDING_EXCEPTION->klass()->klass_part()->name(); + // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark + RC_TRACE_WITH_THREAD(0x00000002, THREAD, + ("verify_byte_codes post merge-CP exception: '%s'", + ex_name->as_C_string())); + CLEAR_PENDING_EXCEPTION; + if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { + return JVMTI_ERROR_OUT_OF_MEMORY; + } else { + // tell the caller that constant pool merging screwed up + return JVMTI_ERROR_INTERNAL; + } + } + } + + Rewriter::rewrite(scratch_class, THREAD); + if (HAS_PENDING_EXCEPTION) { + symbolOop ex_name = PENDING_EXCEPTION->klass()->klass_part()->name(); + CLEAR_PENDING_EXCEPTION; + if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) { + return JVMTI_ERROR_OUT_OF_MEMORY; + } else { + return JVMTI_ERROR_INTERNAL; + } + } + + _scratch_classes[i] = scratch_class; + + // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark + RC_TRACE_WITH_THREAD(0x00000001, THREAD, + ("loaded name=%s (avail_mem=" UINT64_FORMAT "K)", + the_class->external_name(), os::available_memory() >> 10)); + } + + return JVMTI_ERROR_NONE; +} + + +// Map old_index to new_index as needed. scratch_cp is only needed +// for RC_TRACE() calls. +void VM_RedefineClasses::map_index(constantPoolHandle scratch_cp, + int old_index, int new_index) { + if (find_new_index(old_index) != 0) { + // old_index is already mapped + return; + } + + if (old_index == new_index) { + // no mapping is needed + return; + } + + _index_map_p->at_put(old_index, new_index); + _index_map_count++; + + RC_TRACE(0x00040000, ("mapped tag %d at index %d to %d", + scratch_cp->tag_at(old_index).value(), old_index, new_index)); +} // end map_index() + + +// Merge old_cp and scratch_cp and return the results of the merge via +// merge_cp_p. The number of entries in *merge_cp_p is returned via +// merge_cp_length_p. The entries in old_cp occupy the same locations +// in *merge_cp_p. Also creates a map of indices from entries in +// scratch_cp to the corresponding entry in *merge_cp_p. Index map +// entries are only created for entries in scratch_cp that occupy a +// different location in *merged_cp_p. +bool VM_RedefineClasses::merge_constant_pools(constantPoolHandle old_cp, + constantPoolHandle scratch_cp, constantPoolHandle *merge_cp_p, + int *merge_cp_length_p, TRAPS) { + + if (merge_cp_p == NULL) { + assert(false, "caller must provide scatch constantPool"); + return false; // robustness + } + if (merge_cp_length_p == NULL) { + assert(false, "caller must provide scatch CP length"); + return false; // robustness + } + // Worst case we need old_cp->length() + scratch_cp()->length(), + // but the caller might be smart so make sure we have at least + // the minimum. + if ((*merge_cp_p)->length() < old_cp->length()) { + assert(false, "merge area too small"); + return false; // robustness + } + + RC_TRACE_WITH_THREAD(0x00010000, THREAD, + ("old_cp_len=%d, scratch_cp_len=%d", old_cp->length(), + scratch_cp->length())); + + { + // Pass 0: + // The old_cp is copied to *merge_cp_p; this means that any code + // using old_cp does not have to change. This work looks like a + // perfect fit for constantPoolOop::copy_cp_to(), but we need to + // handle one special case: + // - revert JVM_CONSTANT_Class to JVM_CONSTANT_UnresolvedClass + // This will make verification happy. + + int old_i; // index into old_cp + + // index zero (0) is not used in constantPools + for (old_i = 1; old_i < old_cp->length(); old_i++) { + // leave debugging crumb + jbyte old_tag = old_cp->tag_at(old_i).value(); + switch (old_tag) { + case JVM_CONSTANT_Class: + // revert the copy to JVM_CONSTANT_UnresolvedClass + (*merge_cp_p)->unresolved_klass_at_put(old_i, + old_cp->klass_name_at(old_i)); + break; + + case JVM_CONSTANT_Double: + case JVM_CONSTANT_Long: + // just copy the entry to *merge_cp_p, but double and long take + // two constant pool entries + old_cp->copy_entry_to(old_i, *merge_cp_p, old_i, CHECK_0); + old_i++; + break; + + default: + // just copy the entry to *merge_cp_p + old_cp->copy_entry_to(old_i, *merge_cp_p, old_i, CHECK_0); + break; + } + } // end for each old_cp entry + + // We don't need to sanity check that *merge_cp_length_p is within + // *merge_cp_p bounds since we have the minimum on-entry check above. + (*merge_cp_length_p) = old_i; + } + + // merge_cp_len should be the same as old_cp->length() at this point + // so this trace message is really a "warm-and-breathing" message. + RC_TRACE_WITH_THREAD(0x00020000, THREAD, + ("after pass 0: merge_cp_len=%d", *merge_cp_length_p)); + + int scratch_i; // index into scratch_cp + { + // Pass 1a: + // Compare scratch_cp entries to the old_cp entries that we have + // already copied to *merge_cp_p. In this pass, we are eliminating + // exact duplicates (matching entry at same index) so we only + // compare entries in the common indice range. + int increment = 1; + int pass1a_length = MIN2(old_cp->length(), scratch_cp->length()); + for (scratch_i = 1; scratch_i < pass1a_length; scratch_i += increment) { + switch (scratch_cp->tag_at(scratch_i).value()) { + case JVM_CONSTANT_Double: + case JVM_CONSTANT_Long: + // double and long take two constant pool entries + increment = 2; + break; + + default: + increment = 1; + break; + } + + bool match = scratch_cp->compare_entry_to(scratch_i, *merge_cp_p, + scratch_i, CHECK_0); + if (match) { + // found a match at the same index so nothing more to do + continue; + } else if (is_unresolved_class_mismatch(scratch_cp, scratch_i, + *merge_cp_p, scratch_i)) { + // The mismatch in compare_entry_to() above is because of a + // resolved versus unresolved class entry at the same index + // with the same string value. Since Pass 0 reverted any + // class entries to unresolved class entries in *merge_cp_p, + // we go with the unresolved class entry. + continue; + } else if (is_unresolved_string_mismatch(scratch_cp, scratch_i, + *merge_cp_p, scratch_i)) { + // The mismatch in compare_entry_to() above is because of a + // resolved versus unresolved string entry at the same index + // with the same string value. We can live with whichever + // happens to be at scratch_i in *merge_cp_p. + continue; + } + + int found_i = scratch_cp->find_matching_entry(scratch_i, *merge_cp_p, + CHECK_0); + if (found_i != 0) { + guarantee(found_i != scratch_i, + "compare_entry_to() and find_matching_entry() do not agree"); + + // Found a matching entry somewhere else in *merge_cp_p so + // just need a mapping entry. + map_index(scratch_cp, scratch_i, found_i); + continue; + } + + // The find_matching_entry() call above could fail to find a match + // due to a resolved versus unresolved class or string entry situation + // like we solved above with the is_unresolved_*_mismatch() calls. + // However, we would have to call is_unresolved_*_mismatch() over + // all of *merge_cp_p (potentially) and that doesn't seem to be + // worth the time. + + // No match found so we have to append this entry and any unique + // referenced entries to *merge_cp_p. + append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p, + CHECK_0); + } + } + + RC_TRACE_WITH_THREAD(0x00020000, THREAD, + ("after pass 1a: merge_cp_len=%d, scratch_i=%d, index_map_len=%d", + *merge_cp_length_p, scratch_i, _index_map_count)); + + if (scratch_i < scratch_cp->length()) { + // Pass 1b: + // old_cp is smaller than scratch_cp so there are entries in + // scratch_cp that we have not yet processed. We take care of + // those now. + int increment = 1; + for (; scratch_i < scratch_cp->length(); scratch_i += increment) { + switch (scratch_cp->tag_at(scratch_i).value()) { + case JVM_CONSTANT_Double: + case JVM_CONSTANT_Long: + // double and long take two constant pool entries + increment = 2; + break; + + default: + increment = 1; + break; + } + + int found_i = + scratch_cp->find_matching_entry(scratch_i, *merge_cp_p, CHECK_0); + if (found_i != 0) { + // Found a matching entry somewhere else in *merge_cp_p so + // just need a mapping entry. + map_index(scratch_cp, scratch_i, found_i); + continue; + } + + // No match found so we have to append this entry and any unique + // referenced entries to *merge_cp_p. + append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p, + CHECK_0); + } + + RC_TRACE_WITH_THREAD(0x00020000, THREAD, + ("after pass 1b: merge_cp_len=%d, scratch_i=%d, index_map_len=%d", + *merge_cp_length_p, scratch_i, _index_map_count)); + } + + return true; +} // end merge_constant_pools() + + +// Merge constant pools between the_class and scratch_class and +// potentially rewrite bytecodes in scratch_class to use the merged +// constant pool. +jvmtiError VM_RedefineClasses::merge_cp_and_rewrite( + instanceKlassHandle the_class, instanceKlassHandle scratch_class, + TRAPS) { + // worst case merged constant pool length is old and new combined + int merge_cp_length = the_class->constants()->length() + + scratch_class->constants()->length(); + + constantPoolHandle old_cp(THREAD, the_class->constants()); + constantPoolHandle scratch_cp(THREAD, scratch_class->constants()); + + // Constant pools are not easily reused so we allocate a new one + // each time. + constantPoolHandle merge_cp(THREAD, + oopFactory::new_constantPool(merge_cp_length, THREAD)); + int orig_length = old_cp->orig_length(); + if (orig_length == 0) { + // This old_cp is an actual original constant pool. We save + // the original length in the merged constant pool so that + // merge_constant_pools() can be more efficient. If a constant + // pool has a non-zero orig_length() value, then that constant + // pool was created by a merge operation in RedefineClasses. + merge_cp->set_orig_length(old_cp->length()); + } else { + // This old_cp is a merged constant pool from a previous + // RedefineClasses() calls so just copy the orig_length() + // value. + merge_cp->set_orig_length(old_cp->orig_length()); + } + + ResourceMark rm(THREAD); + _index_map_count = 0; + _index_map_p = new intArray(scratch_cp->length(), -1); + + bool result = merge_constant_pools(old_cp, scratch_cp, &merge_cp, + &merge_cp_length, THREAD); + if (!result) { + // The merge can fail due to memory allocation failure or due + // to robustness checks. + return JVMTI_ERROR_INTERNAL; + } + + RC_TRACE_WITH_THREAD(0x00010000, THREAD, + ("merge_cp_len=%d, index_map_len=%d", merge_cp_length, _index_map_count)); + + if (_index_map_count == 0) { + // there is nothing to map between the new and merged constant pools + + if (old_cp->length() == scratch_cp->length()) { + // The old and new constant pools are the same length and the + // index map is empty. This means that the three constant pools + // are equivalent (but not the same). Unfortunately, the new + // constant pool has not gone through link resolution nor have + // the new class bytecodes gone through constant pool cache + // rewriting so we can't use the old constant pool with the new + // class. + + merge_cp = constantPoolHandle(); // toss the merged constant pool + } else if (old_cp->length() < scratch_cp->length()) { + // The old constant pool has fewer entries than the new constant + // pool and the index map is empty. This means the new constant + // pool is a superset of the old constant pool. However, the old + // class bytecodes have already gone through constant pool cache + // rewriting so we can't use the new constant pool with the old + // class. + + merge_cp = constantPoolHandle(); // toss the merged constant pool + } else { + // The old constant pool has more entries than the new constant + // pool and the index map is empty. This means that both the old + // and merged constant pools are supersets of the new constant + // pool. + + // Replace the new constant pool with a shrunken copy of the + // merged constant pool; the previous new constant pool will + // get GCed. + set_new_constant_pool(scratch_class, merge_cp, merge_cp_length, true, + THREAD); + // drop local ref to the merged constant pool + merge_cp = constantPoolHandle(); + } + } else { + if (RC_TRACE_ENABLED(0x00040000)) { + // don't want to loop unless we are tracing + int count = 0; + for (int i = 1; i < _index_map_p->length(); i++) { + int value = _index_map_p->at(i); + + if (value != -1) { + RC_TRACE_WITH_THREAD(0x00040000, THREAD, + ("index_map[%d]: old=%d new=%d", count, i, value)); + count++; + } + } + } + + // We have entries mapped between the new and merged constant pools + // so we have to rewrite some constant pool references. + if (!rewrite_cp_refs(scratch_class, THREAD)) { + return JVMTI_ERROR_INTERNAL; + } + + // Replace the new constant pool with a shrunken copy of the + // merged constant pool so now the rewritten bytecodes have + // valid references; the previous new constant pool will get + // GCed. + set_new_constant_pool(scratch_class, merge_cp, merge_cp_length, true, + THREAD); + } + + return JVMTI_ERROR_NONE; +} // end merge_cp_and_rewrite() + + +// Rewrite constant pool references in klass scratch_class. +bool VM_RedefineClasses::rewrite_cp_refs(instanceKlassHandle scratch_class, + TRAPS) { + + // rewrite constant pool references in the methods: + if (!rewrite_cp_refs_in_methods(scratch_class, THREAD)) { + // propogate failure back to caller + return false; + } + + // rewrite constant pool references in the class_annotations: + if (!rewrite_cp_refs_in_class_annotations(scratch_class, THREAD)) { + // propogate failure back to caller + return false; + } + + // rewrite constant pool references in the fields_annotations: + if (!rewrite_cp_refs_in_fields_annotations(scratch_class, THREAD)) { + // propogate failure back to caller + return false; + } + + // rewrite constant pool references in the methods_annotations: + if (!rewrite_cp_refs_in_methods_annotations(scratch_class, THREAD)) { + // propogate failure back to caller + return false; + } + + // rewrite constant pool references in the methods_parameter_annotations: + if (!rewrite_cp_refs_in_methods_parameter_annotations(scratch_class, + THREAD)) { + // propogate failure back to caller + return false; + } + + // rewrite constant pool references in the methods_default_annotations: + if (!rewrite_cp_refs_in_methods_default_annotations(scratch_class, + THREAD)) { + // propogate failure back to caller + return false; + } + + return true; +} // end rewrite_cp_refs() + + +// Rewrite constant pool references in the methods. +bool VM_RedefineClasses::rewrite_cp_refs_in_methods( + instanceKlassHandle scratch_class, TRAPS) { + + objArrayHandle methods(THREAD, scratch_class->methods()); + + if (methods.is_null() || methods->length() == 0) { + // no methods so nothing to do + return true; + } + + // rewrite constant pool references in the methods: + for (int i = methods->length() - 1; i >= 0; i--) { + methodHandle method(THREAD, (methodOop)methods->obj_at(i)); + methodHandle new_method; + rewrite_cp_refs_in_method(method, &new_method, CHECK_false); + if (!new_method.is_null()) { + // the method has been replaced so save the new method version + methods->obj_at_put(i, new_method()); + } + } + + return true; +} + + +// Rewrite constant pool references in the specific method. This code +// was adapted from Rewriter::rewrite_method(). +void VM_RedefineClasses::rewrite_cp_refs_in_method(methodHandle method, + methodHandle *new_method_p, TRAPS) { + + *new_method_p = methodHandle(); // default is no new method + + // We cache a pointer to the bytecodes here in code_base. If GC + // moves the methodOop, then the bytecodes will also move which + // will likely cause a crash. We create a No_Safepoint_Verifier + // object to detect whether we pass a possible safepoint in this + // code block. + No_Safepoint_Verifier nsv; + + // Bytecodes and their length + address code_base = method->code_base(); + int code_length = method->code_size(); + + int bc_length; + for (int bci = 0; bci < code_length; bci += bc_length) { + address bcp = code_base + bci; + Bytecodes::Code c = (Bytecodes::Code)(*bcp); + + bc_length = Bytecodes::length_for(c); + if (bc_length == 0) { + // More complicated bytecodes report a length of zero so + // we have to try again a slightly different way. + bc_length = Bytecodes::length_at(bcp); + } + + assert(bc_length != 0, "impossible bytecode length"); + + switch (c) { + case Bytecodes::_ldc: + { + int cp_index = *(bcp + 1); + int new_index = find_new_index(cp_index); + + if (StressLdcRewrite && new_index == 0) { + // If we are stressing ldc -> ldc_w rewriting, then we + // always need a new_index value. + new_index = cp_index; + } + if (new_index != 0) { + // the original index is mapped so we have more work to do + if (!StressLdcRewrite && new_index <= max_jubyte) { + // The new value can still use ldc instead of ldc_w + // unless we are trying to stress ldc -> ldc_w rewriting + RC_TRACE_WITH_THREAD(0x00080000, THREAD, + ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c), + bcp, cp_index, new_index)); + *(bcp + 1) = new_index; + } else { + RC_TRACE_WITH_THREAD(0x00080000, THREAD, + ("%s->ldc_w@" INTPTR_FORMAT " old=%d, new=%d", + Bytecodes::name(c), bcp, cp_index, new_index)); + // the new value needs ldc_w instead of ldc + u_char inst_buffer[4]; // max instruction size is 4 bytes + bcp = (address)inst_buffer; + // construct new instruction sequence + *bcp = Bytecodes::_ldc_w; + bcp++; + // Rewriter::rewrite_method() does not rewrite ldc -> ldc_w. + // See comment below for difference between put_Java_u2() + // and put_native_u2(). + Bytes::put_Java_u2(bcp, new_index); + + Relocator rc(method, NULL /* no RelocatorListener needed */); + methodHandle m; + { + Pause_No_Safepoint_Verifier pnsv(&nsv); + + // ldc is 2 bytes and ldc_w is 3 bytes + m = rc.insert_space_at(bci, 3, inst_buffer, THREAD); + if (m.is_null() || HAS_PENDING_EXCEPTION) { + guarantee(false, "insert_space_at() failed"); + } + } + + // return the new method so that the caller can update + // the containing class + *new_method_p = method = m; + // switch our bytecode processing loop from the old method + // to the new method + code_base = method->code_base(); + code_length = method->code_size(); + bcp = code_base + bci; + c = (Bytecodes::Code)(*bcp); + bc_length = Bytecodes::length_for(c); + assert(bc_length != 0, "sanity check"); + } // end we need ldc_w instead of ldc + } // end if there is a mapped index + } break; + + // these bytecodes have a two-byte constant pool index + case Bytecodes::_anewarray : // fall through + case Bytecodes::_checkcast : // fall through + case Bytecodes::_getfield : // fall through + case Bytecodes::_getstatic : // fall through + case Bytecodes::_instanceof : // fall through + case Bytecodes::_invokeinterface: // fall through + case Bytecodes::_invokespecial : // fall through + case Bytecodes::_invokestatic : // fall through + case Bytecodes::_invokevirtual : // fall through + case Bytecodes::_ldc_w : // fall through + case Bytecodes::_ldc2_w : // fall through + case Bytecodes::_multianewarray : // fall through + case Bytecodes::_new : // fall through + case Bytecodes::_putfield : // fall through + case Bytecodes::_putstatic : + { + address p = bcp + 1; + int cp_index = Bytes::get_Java_u2(p); + int new_index = find_new_index(cp_index); + if (new_index != 0) { + // the original index is mapped so update w/ new value + RC_TRACE_WITH_THREAD(0x00080000, THREAD, + ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c), + bcp, cp_index, new_index)); + // Rewriter::rewrite_method() uses put_native_u2() in this + // situation because it is reusing the constant pool index + // location for a native index into the constantPoolCache. + // Since we are updating the constant pool index prior to + // verification and constantPoolCache initialization, we + // need to keep the new index in Java byte order. + Bytes::put_Java_u2(p, new_index); + } + } break; + } + } // end for each bytecode +} // end rewrite_cp_refs_in_method() + + +// Rewrite constant pool references in the class_annotations field. +bool VM_RedefineClasses::rewrite_cp_refs_in_class_annotations( + instanceKlassHandle scratch_class, TRAPS) { + + typeArrayHandle class_annotations(THREAD, + scratch_class->class_annotations()); + if (class_annotations.is_null() || class_annotations->length() == 0) { + // no class_annotations so nothing to do + return true; + } + + RC_TRACE_WITH_THREAD(0x02000000, THREAD, + ("class_annotations length=%d", class_annotations->length())); + + int byte_i = 0; // byte index into class_annotations + return rewrite_cp_refs_in_annotations_typeArray(class_annotations, byte_i, + THREAD); +} + + +// Rewrite constant pool references in an annotations typeArray. This +// "structure" is adapted from the RuntimeVisibleAnnotations_attribute +// that is described in section 4.8.15 of the 2nd-edition of the VM spec: +// +// annotations_typeArray { +// u2 num_annotations; +// annotation annotations[num_annotations]; +// } +// +bool VM_RedefineClasses::rewrite_cp_refs_in_annotations_typeArray( + typeArrayHandle annotations_typeArray, int &byte_i_ref, TRAPS) { + + if ((byte_i_ref + 2) > annotations_typeArray->length()) { + // not enough room for num_annotations field + RC_TRACE_WITH_THREAD(0x02000000, THREAD, + ("length() is too small for num_annotations field")); + return false; + } + + u2 num_annotations = Bytes::get_Java_u2((address) + annotations_typeArray->byte_at_addr(byte_i_ref)); + byte_i_ref += 2; + + RC_TRACE_WITH_THREAD(0x02000000, THREAD, + ("num_annotations=%d", num_annotations)); + + int calc_num_annotations = 0; + for (; calc_num_annotations < num_annotations; calc_num_annotations++) { + if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray, + byte_i_ref, THREAD)) { + RC_TRACE_WITH_THREAD(0x02000000, THREAD, + ("bad annotation_struct at %d", calc_num_annotations)); + // propogate failure back to caller + return false; + } + } + assert(num_annotations == calc_num_annotations, "sanity check"); + + return true; +} // end rewrite_cp_refs_in_annotations_typeArray() + + +// Rewrite constant pool references in the annotation struct portion of +// an annotations_typeArray. This "structure" is from section 4.8.15 of +// the 2nd-edition of the VM spec: +// +// struct annotation { +// u2 type_index; +// u2 num_element_value_pairs; +// { +// u2 element_name_index; +// element_value value; +// } element_value_pairs[num_element_value_pairs]; +// } +// +bool VM_RedefineClasses::rewrite_cp_refs_in_annotation_struct( + typeArrayHandle annotations_typeArray, int &byte_i_ref, TRAPS) { + if ((byte_i_ref + 2 + 2) > annotations_typeArray->length()) { + // not enough room for smallest annotation_struct + RC_TRACE_WITH_THREAD(0x02000000, THREAD, + ("length() is too small for annotation_struct")); + return false; + } + + u2 type_index = rewrite_cp_ref_in_annotation_data(annotations_typeArray, + byte_i_ref, "mapped old type_index=%d", THREAD); + + u2 num_element_value_pairs = Bytes::get_Java_u2((address) + annotations_typeArray->byte_at_addr( + byte_i_ref)); + byte_i_ref += 2; + + RC_TRACE_WITH_THREAD(0x02000000, THREAD, + ("type_index=%d num_element_value_pairs=%d", type_index, + num_element_value_pairs)); + + int calc_num_element_value_pairs = 0; + for (; calc_num_element_value_pairs < num_element_value_pairs; + calc_num_element_value_pairs++) { + if ((byte_i_ref + 2) > annotations_typeArray->length()) { + // not enough room for another element_name_index, let alone + // the rest of another component + RC_TRACE_WITH_THREAD(0x02000000, THREAD, + ("length() is too small for element_name_index")); + return false; + } + + u2 element_name_index = rewrite_cp_ref_in_annotation_data( + annotations_typeArray, byte_i_ref, + "mapped old element_name_index=%d", THREAD); + + RC_TRACE_WITH_THREAD(0x02000000, THREAD, + ("element_name_index=%d", element_name_index)); + + if (!rewrite_cp_refs_in_element_value(annotations_typeArray, + byte_i_ref, THREAD)) { + RC_TRACE_WITH_THREAD(0x02000000, THREAD, + ("bad element_value at %d", calc_num_element_value_pairs)); + // propogate failure back to caller + return false; + } + } // end for each component + assert(num_element_value_pairs == calc_num_element_value_pairs, + "sanity check"); + + return true; +} // end rewrite_cp_refs_in_annotation_struct() + + +// Rewrite a constant pool reference at the current position in +// annotations_typeArray if needed. Returns the original constant +// pool reference if a rewrite was not needed or the new constant +// pool reference if a rewrite was needed. +u2 VM_RedefineClasses::rewrite_cp_ref_in_annotation_data( + typeArrayHandle annotations_typeArray, int &byte_i_ref, + const char * trace_mesg, TRAPS) { + + address cp_index_addr = (address) + annotations_typeArray->byte_at_addr(byte_i_ref); + u2 old_cp_index = Bytes::get_Java_u2(cp_index_addr); + u2 new_cp_index = find_new_index(old_cp_index); + if (new_cp_index != 0) { + RC_TRACE_WITH_THREAD(0x02000000, THREAD, (trace_mesg, old_cp_index)); + Bytes::put_Java_u2(cp_index_addr, new_cp_index); + old_cp_index = new_cp_index; + } + byte_i_ref += 2; + return old_cp_index; +} + + +// Rewrite constant pool references in the element_value portion of an +// annotations_typeArray. This "structure" is from section 4.8.15.1 of +// the 2nd-edition of the VM spec: +// +// struct element_value { +// u1 tag; +// union { +// u2 const_value_index; +// { +// u2 type_name_index; +// u2 const_name_index; +// } enum_const_value; +// u2 class_info_index; +// annotation annotation_value; +// struct { +// u2 num_values; +// element_value values[num_values]; +// } array_value; +// } value; +// } +// +bool VM_RedefineClasses::rewrite_cp_refs_in_element_value( + typeArrayHandle annotations_typeArray, int &byte_i_ref, TRAPS) { + + if ((byte_i_ref + 1) > annotations_typeArray->length()) { + // not enough room for a tag let alone the rest of an element_value + RC_TRACE_WITH_THREAD(0x02000000, THREAD, + ("length() is too small for a tag")); + return false; + } + + u1 tag = annotations_typeArray->byte_at(byte_i_ref); + byte_i_ref++; + RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("tag='%c'", tag)); + + switch (tag) { + // These BaseType tag values are from Table 4.2 in VM spec: + case 'B': // byte + case 'C': // char + case 'D': // double + case 'F': // float + case 'I': // int + case 'J': // long + case 'S': // short + case 'Z': // boolean + + // The remaining tag values are from Table 4.8 in the 2nd-edition of + // the VM spec: + case 's': + { + // For the above tag values (including the BaseType values), + // value.const_value_index is right union field. + + if ((byte_i_ref + 2) > annotations_typeArray->length()) { + // not enough room for a const_value_index + RC_TRACE_WITH_THREAD(0x02000000, THREAD, + ("length() is too small for a const_value_index")); + return false; + } + + u2 const_value_index = rewrite_cp_ref_in_annotation_data( + annotations_typeArray, byte_i_ref, + "mapped old const_value_index=%d", THREAD); + + RC_TRACE_WITH_THREAD(0x02000000, THREAD, + ("const_value_index=%d", const_value_index)); + } break; + + case 'e': + { + // for the above tag value, value.enum_const_value is right union field + + if ((byte_i_ref + 4) > annotations_typeArray->length()) { + // not enough room for a enum_const_value + RC_TRACE_WITH_THREAD(0x02000000, THREAD, + ("length() is too small for a enum_const_value")); + return false; + } + + u2 type_name_index = rewrite_cp_ref_in_annotation_data( + annotations_typeArray, byte_i_ref, + "mapped old type_name_index=%d", THREAD); + + u2 const_name_index = rewrite_cp_ref_in_annotation_data( + annotations_typeArray, byte_i_ref, + "mapped old const_name_index=%d", THREAD); + + RC_TRACE_WITH_THREAD(0x02000000, THREAD, + ("type_name_index=%d const_name_index=%d", type_name_index, + const_name_index)); + } break; + + case 'c': + { + // for the above tag value, value.class_info_index is right union field + + if ((byte_i_ref + 2) > annotations_typeArray->length()) { + // not enough room for a class_info_index + RC_TRACE_WITH_THREAD(0x02000000, THREAD, + ("length() is too small for a class_info_index")); + return false; + } + + u2 class_info_index = rewrite_cp_ref_in_annotation_data( + annotations_typeArray, byte_i_ref, + "mapped old class_info_index=%d", THREAD); + + RC_TRACE_WITH_THREAD(0x02000000, THREAD, + ("class_info_index=%d", class_info_index)); + } break; + + case '@': + // For the above tag value, value.attr_value is the right union + // field. This is a nested annotation. + if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray, + byte_i_ref, THREAD)) { + // propogate failure back to caller + return false; + } + break; + + case '[': + { + if ((byte_i_ref + 2) > annotations_typeArray->length()) { + // not enough room for a num_values field + RC_TRACE_WITH_THREAD(0x02000000, THREAD, + ("length() is too small for a num_values field")); + return false; + } + + // For the above tag value, value.array_value is the right union + // field. This is an array of nested element_value. + u2 num_values = Bytes::get_Java_u2((address) + annotations_typeArray->byte_at_addr(byte_i_ref)); + byte_i_ref += 2; + RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("num_values=%d", num_values)); + + int calc_num_values = 0; + for (; calc_num_values < num_values; calc_num_values++) { + if (!rewrite_cp_refs_in_element_value( + annotations_typeArray, byte_i_ref, THREAD)) { + RC_TRACE_WITH_THREAD(0x02000000, THREAD, + ("bad nested element_value at %d", calc_num_values)); + // propogate failure back to caller + return false; + } + } + assert(num_values == calc_num_values, "sanity check"); + } break; + + default: + RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("bad tag=0x%x", tag)); + return false; + } // end decode tag field + + return true; +} // end rewrite_cp_refs_in_element_value() + + +// Rewrite constant pool references in a fields_annotations field. +bool VM_RedefineClasses::rewrite_cp_refs_in_fields_annotations( + instanceKlassHandle scratch_class, TRAPS) { + + objArrayHandle fields_annotations(THREAD, + scratch_class->fields_annotations()); + + if (fields_annotations.is_null() || fields_annotations->length() == 0) { + // no fields_annotations so nothing to do + return true; + } + + RC_TRACE_WITH_THREAD(0x02000000, THREAD, + ("fields_annotations length=%d", fields_annotations->length())); + + for (int i = 0; i < fields_annotations->length(); i++) { + typeArrayHandle field_annotations(THREAD, + (typeArrayOop)fields_annotations->obj_at(i)); + if (field_annotations.is_null() || field_annotations->length() == 0) { + // this field does not have any annotations so skip it + continue; + } + + int byte_i = 0; // byte index into field_annotations + if (!rewrite_cp_refs_in_annotations_typeArray(field_annotations, byte_i, + THREAD)) { + RC_TRACE_WITH_THREAD(0x02000000, THREAD, + ("bad field_annotations at %d", i)); + // propogate failure back to caller + return false; + } + } + + return true; +} // end rewrite_cp_refs_in_fields_annotations() + + +// Rewrite constant pool references in a methods_annotations field. +bool VM_RedefineClasses::rewrite_cp_refs_in_methods_annotations( + instanceKlassHandle scratch_class, TRAPS) { + + objArrayHandle methods_annotations(THREAD, + scratch_class->methods_annotations()); + + if (methods_annotations.is_null() || methods_annotations->length() == 0) { + // no methods_annotations so nothing to do + return true; + } + + RC_TRACE_WITH_THREAD(0x02000000, THREAD, + ("methods_annotations length=%d", methods_annotations->length())); + + for (int i = 0; i < methods_annotations->length(); i++) { + typeArrayHandle method_annotations(THREAD, + (typeArrayOop)methods_annotations->obj_at(i)); + if (method_annotations.is_null() || method_annotations->length() == 0) { + // this method does not have any annotations so skip it + continue; + } + + int byte_i = 0; // byte index into method_annotations + if (!rewrite_cp_refs_in_annotations_typeArray(method_annotations, byte_i, + THREAD)) { + RC_TRACE_WITH_THREAD(0x02000000, THREAD, + ("bad method_annotations at %d", i)); + // propogate failure back to caller + return false; + } + } + + return true; +} // end rewrite_cp_refs_in_methods_annotations() + + +// Rewrite constant pool references in a methods_parameter_annotations +// field. This "structure" is adapted from the +// RuntimeVisibleParameterAnnotations_attribute described in section +// 4.8.17 of the 2nd-edition of the VM spec: +// +// methods_parameter_annotations_typeArray { +// u1 num_parameters; +// { +// u2 num_annotations; +// annotation annotations[num_annotations]; +// } parameter_annotations[num_parameters]; +// } +// +bool VM_RedefineClasses::rewrite_cp_refs_in_methods_parameter_annotations( + instanceKlassHandle scratch_class, TRAPS) { + + objArrayHandle methods_parameter_annotations(THREAD, + scratch_class->methods_parameter_annotations()); + + if (methods_parameter_annotations.is_null() + || methods_parameter_annotations->length() == 0) { + // no methods_parameter_annotations so nothing to do + return true; + } + + RC_TRACE_WITH_THREAD(0x02000000, THREAD, + ("methods_parameter_annotations length=%d", + methods_parameter_annotations->length())); + + for (int i = 0; i < methods_parameter_annotations->length(); i++) { + typeArrayHandle method_parameter_annotations(THREAD, + (typeArrayOop)methods_parameter_annotations->obj_at(i)); + if (method_parameter_annotations.is_null() + || method_parameter_annotations->length() == 0) { + // this method does not have any parameter annotations so skip it + continue; + } + + if (method_parameter_annotations->length() < 1) { + // not enough room for a num_parameters field + RC_TRACE_WITH_THREAD(0x02000000, THREAD, + ("length() is too small for a num_parameters field at %d", i)); + return false; + } + + int byte_i = 0; // byte index into method_parameter_annotations + + u1 num_parameters = method_parameter_annotations->byte_at(byte_i); + byte_i++; + + RC_TRACE_WITH_THREAD(0x02000000, THREAD, + ("num_parameters=%d", num_parameters)); + + int calc_num_parameters = 0; + for (; calc_num_parameters < num_parameters; calc_num_parameters++) { + if (!rewrite_cp_refs_in_annotations_typeArray( + method_parameter_annotations, byte_i, THREAD)) { + RC_TRACE_WITH_THREAD(0x02000000, THREAD, + ("bad method_parameter_annotations at %d", calc_num_parameters)); + // propogate failure back to caller + return false; + } + } + assert(num_parameters == calc_num_parameters, "sanity check"); + } + + return true; +} // end rewrite_cp_refs_in_methods_parameter_annotations() + + +// Rewrite constant pool references in a methods_default_annotations +// field. This "structure" is adapted from the AnnotationDefault_attribute +// that is described in section 4.8.19 of the 2nd-edition of the VM spec: +// +// methods_default_annotations_typeArray { +// element_value default_value; +// } +// +bool VM_RedefineClasses::rewrite_cp_refs_in_methods_default_annotations( + instanceKlassHandle scratch_class, TRAPS) { + + objArrayHandle methods_default_annotations(THREAD, + scratch_class->methods_default_annotations()); + + if (methods_default_annotations.is_null() + || methods_default_annotations->length() == 0) { + // no methods_default_annotations so nothing to do + return true; + } + + RC_TRACE_WITH_THREAD(0x02000000, THREAD, + ("methods_default_annotations length=%d", + methods_default_annotations->length())); + + for (int i = 0; i < methods_default_annotations->length(); i++) { + typeArrayHandle method_default_annotations(THREAD, + (typeArrayOop)methods_default_annotations->obj_at(i)); + if (method_default_annotations.is_null() + || method_default_annotations->length() == 0) { + // this method does not have any default annotations so skip it + continue; + } + + int byte_i = 0; // byte index into method_default_annotations + + if (!rewrite_cp_refs_in_element_value( + method_default_annotations, byte_i, THREAD)) { + RC_TRACE_WITH_THREAD(0x02000000, THREAD, + ("bad default element_value at %d", i)); + // propogate failure back to caller + return false; + } + } + + return true; +} // end rewrite_cp_refs_in_methods_default_annotations() + + +// Rewrite constant pool references in the method's stackmap table. +// These "structures" are adapted from the StackMapTable_attribute that +// is described in section 4.8.4 of the 6.0 version of the VM spec +// (dated 2005.10.26): +// file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf +// +// stack_map { +// u2 number_of_entries; +// stack_map_frame entries[number_of_entries]; +// } +// +void VM_RedefineClasses::rewrite_cp_refs_in_stack_map_table( + methodHandle method, TRAPS) { + + if (!method->has_stackmap_table()) { + return; + } + + typeArrayOop stackmap_data = method->stackmap_data(); + address stackmap_p = (address)stackmap_data->byte_at_addr(0); + address stackmap_end = stackmap_p + stackmap_data->length(); + + assert(stackmap_p + 2 <= stackmap_end, "no room for number_of_entries"); + u2 number_of_entries = Bytes::get_Java_u2(stackmap_p); + stackmap_p += 2; + + RC_TRACE_WITH_THREAD(0x04000000, THREAD, + ("number_of_entries=%u", number_of_entries)); + + // walk through each stack_map_frame + u2 calc_number_of_entries = 0; + for (; calc_number_of_entries < number_of_entries; calc_number_of_entries++) { + // The stack_map_frame structure is a u1 frame_type followed by + // 0 or more bytes of data: + // + // union stack_map_frame { + // same_frame; + // same_locals_1_stack_item_frame; + // same_locals_1_stack_item_frame_extended; + // chop_frame; + // same_frame_extended; + // append_frame; + // full_frame; + // } + + assert(stackmap_p + 1 <= stackmap_end, "no room for frame_type"); + // The Linux compiler does not like frame_type to be u1 or u2. It + // issues the following warning for the first if-statement below: + // + // "warning: comparison is always true due to limited range of data type" + // + u4 frame_type = *stackmap_p; + stackmap_p++; + + // same_frame { + // u1 frame_type = SAME; /* 0-63 */ + // } + if (frame_type >= 0 && frame_type <= 63) { + // nothing more to do for same_frame + } + + // same_locals_1_stack_item_frame { + // u1 frame_type = SAME_LOCALS_1_STACK_ITEM; /* 64-127 */ + // verification_type_info stack[1]; + // } + else if (frame_type >= 64 && frame_type <= 127) { + rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end, + calc_number_of_entries, frame_type, THREAD); + } + + // reserved for future use + else if (frame_type >= 128 && frame_type <= 246) { + // nothing more to do for reserved frame_types + } + + // same_locals_1_stack_item_frame_extended { + // u1 frame_type = SAME_LOCALS_1_STACK_ITEM_EXTENDED; /* 247 */ + // u2 offset_delta; + // verification_type_info stack[1]; + // } + else if (frame_type == 247) { + stackmap_p += 2; + rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end, + calc_number_of_entries, frame_type, THREAD); + } + + // chop_frame { + // u1 frame_type = CHOP; /* 248-250 */ + // u2 offset_delta; + // } + else if (frame_type >= 248 && frame_type <= 250) { + stackmap_p += 2; + } + + // same_frame_extended { + // u1 frame_type = SAME_FRAME_EXTENDED; /* 251*/ + // u2 offset_delta; + // } + else if (frame_type == 251) { + stackmap_p += 2; + } + + // append_frame { + // u1 frame_type = APPEND; /* 252-254 */ + // u2 offset_delta; + // verification_type_info locals[frame_type - 251]; + // } + else if (frame_type >= 252 && frame_type <= 254) { + assert(stackmap_p + 2 <= stackmap_end, + "no room for offset_delta"); + stackmap_p += 2; + u1 len = frame_type - 251; + for (u1 i = 0; i < len; i++) { + rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end, + calc_number_of_entries, frame_type, THREAD); + } + } + + // full_frame { + // u1 frame_type = FULL_FRAME; /* 255 */ + // u2 offset_delta; + // u2 number_of_locals; + // verification_type_info locals[number_of_locals]; + // u2 number_of_stack_items; + // verification_type_info stack[number_of_stack_items]; + // } + else if (frame_type == 255) { + assert(stackmap_p + 2 + 2 <= stackmap_end, + "no room for smallest full_frame"); + stackmap_p += 2; + + u2 number_of_locals = Bytes::get_Java_u2(stackmap_p); + stackmap_p += 2; + + for (u2 locals_i = 0; locals_i < number_of_locals; locals_i++) { + rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end, + calc_number_of_entries, frame_type, THREAD); + } + + // Use the largest size for the number_of_stack_items, but only get + // the right number of bytes. + u2 number_of_stack_items = Bytes::get_Java_u2(stackmap_p); + stackmap_p += 2; + + for (u2 stack_i = 0; stack_i < number_of_stack_items; stack_i++) { + rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end, + calc_number_of_entries, frame_type, THREAD); + } + } + } // end while there is a stack_map_frame + assert(number_of_entries == calc_number_of_entries, "sanity check"); +} // end rewrite_cp_refs_in_stack_map_table() + + +// Rewrite constant pool references in the verification type info +// portion of the method's stackmap table. These "structures" are +// adapted from the StackMapTable_attribute that is described in +// section 4.8.4 of the 6.0 version of the VM spec (dated 2005.10.26): +// file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf +// +// The verification_type_info structure is a u1 tag followed by 0 or +// more bytes of data: +// +// union verification_type_info { +// Top_variable_info; +// Integer_variable_info; +// Float_variable_info; +// Long_variable_info; +// Double_variable_info; +// Null_variable_info; +// UninitializedThis_variable_info; +// Object_variable_info; +// Uninitialized_variable_info; +// } +// +void VM_RedefineClasses::rewrite_cp_refs_in_verification_type_info( + address& stackmap_p_ref, address stackmap_end, u2 frame_i, + u1 frame_type, TRAPS) { + + assert(stackmap_p_ref + 1 <= stackmap_end, "no room for tag"); + u1 tag = *stackmap_p_ref; + stackmap_p_ref++; + + switch (tag) { + // Top_variable_info { + // u1 tag = ITEM_Top; /* 0 */ + // } + // verificationType.hpp has zero as ITEM_Bogus instead of ITEM_Top + case 0: // fall through + + // Integer_variable_info { + // u1 tag = ITEM_Integer; /* 1 */ + // } + case ITEM_Integer: // fall through + + // Float_variable_info { + // u1 tag = ITEM_Float; /* 2 */ + // } + case ITEM_Float: // fall through + + // Double_variable_info { + // u1 tag = ITEM_Double; /* 3 */ + // } + case ITEM_Double: // fall through + + // Long_variable_info { + // u1 tag = ITEM_Long; /* 4 */ + // } + case ITEM_Long: // fall through + + // Null_variable_info { + // u1 tag = ITEM_Null; /* 5 */ + // } + case ITEM_Null: // fall through + + // UninitializedThis_variable_info { + // u1 tag = ITEM_UninitializedThis; /* 6 */ + // } + case ITEM_UninitializedThis: + // nothing more to do for the above tag types + break; + + // Object_variable_info { + // u1 tag = ITEM_Object; /* 7 */ + // u2 cpool_index; + // } + case ITEM_Object: + { + assert(stackmap_p_ref + 2 <= stackmap_end, "no room for cpool_index"); + u2 cpool_index = Bytes::get_Java_u2(stackmap_p_ref); + u2 new_cp_index = find_new_index(cpool_index); + if (new_cp_index != 0) { + RC_TRACE_WITH_THREAD(0x04000000, THREAD, + ("mapped old cpool_index=%d", cpool_index)); + Bytes::put_Java_u2(stackmap_p_ref, new_cp_index); + cpool_index = new_cp_index; + } + stackmap_p_ref += 2; + + RC_TRACE_WITH_THREAD(0x04000000, THREAD, + ("frame_i=%u, frame_type=%u, cpool_index=%d", frame_i, + frame_type, cpool_index)); + } break; + + // Uninitialized_variable_info { + // u1 tag = ITEM_Uninitialized; /* 8 */ + // u2 offset; + // } + case ITEM_Uninitialized: + assert(stackmap_p_ref + 2 <= stackmap_end, "no room for offset"); + stackmap_p_ref += 2; + break; + + default: + RC_TRACE_WITH_THREAD(0x04000000, THREAD, + ("frame_i=%u, frame_type=%u, bad tag=0x%x", frame_i, frame_type, tag)); + ShouldNotReachHere(); + break; + } // end switch (tag) +} // end rewrite_cp_refs_in_verification_type_info() + + +// Change the constant pool associated with klass scratch_class to +// scratch_cp. If shrink is true, then scratch_cp_length elements +// are copied from scratch_cp to a smaller constant pool and the +// smaller constant pool is associated with scratch_class. +void VM_RedefineClasses::set_new_constant_pool( + instanceKlassHandle scratch_class, constantPoolHandle scratch_cp, + int scratch_cp_length, bool shrink, TRAPS) { + assert(!shrink || scratch_cp->length() >= scratch_cp_length, "sanity check"); + + if (shrink) { + // scratch_cp is a merged constant pool and has enough space for a + // worst case merge situation. We want to associate the minimum + // sized constant pool with the klass to save space. + constantPoolHandle smaller_cp(THREAD, + oopFactory::new_constantPool(scratch_cp_length, THREAD)); + // preserve orig_length() value in the smaller copy + int orig_length = scratch_cp->orig_length(); + assert(orig_length != 0, "sanity check"); + smaller_cp->set_orig_length(orig_length); + scratch_cp->copy_cp_to(1, scratch_cp_length - 1, smaller_cp, 1, THREAD); + scratch_cp = smaller_cp; + } + + // attach new constant pool to klass + scratch_cp->set_pool_holder(scratch_class()); + + // attach klass to new constant pool + scratch_class->set_constants(scratch_cp()); + + int i; // for portability + + // update each field in klass to use new constant pool indices as needed + typeArrayHandle fields(THREAD, scratch_class->fields()); + int n_fields = fields->length(); + for (i = 0; i < n_fields; i += instanceKlass::next_offset) { + jshort cur_index = fields->short_at(i + instanceKlass::name_index_offset); + jshort new_index = find_new_index(cur_index); + if (new_index != 0) { + RC_TRACE_WITH_THREAD(0x00080000, THREAD, + ("field-name_index change: %d to %d", cur_index, new_index)); + fields->short_at_put(i + instanceKlass::name_index_offset, new_index); + } + cur_index = fields->short_at(i + instanceKlass::signature_index_offset); + new_index = find_new_index(cur_index); + if (new_index != 0) { + RC_TRACE_WITH_THREAD(0x00080000, THREAD, + ("field-signature_index change: %d to %d", cur_index, new_index)); + fields->short_at_put(i + instanceKlass::signature_index_offset, + new_index); + } + cur_index = fields->short_at(i + instanceKlass::initval_index_offset); + new_index = find_new_index(cur_index); + if (new_index != 0) { + RC_TRACE_WITH_THREAD(0x00080000, THREAD, + ("field-initval_index change: %d to %d", cur_index, new_index)); + fields->short_at_put(i + instanceKlass::initval_index_offset, new_index); + } + cur_index = fields->short_at(i + instanceKlass::generic_signature_offset); + new_index = find_new_index(cur_index); + if (new_index != 0) { + RC_TRACE_WITH_THREAD(0x00080000, THREAD, + ("field-generic_signature change: %d to %d", cur_index, new_index)); + fields->short_at_put(i + instanceKlass::generic_signature_offset, + new_index); + } + } // end for each field + + // Update constant pool indices in the inner classes info to use + // new constant indices as needed. The inner classes info is a + // quadruple: + // (inner_class_info, outer_class_info, inner_name, inner_access_flags) + typeArrayOop inner_class_list = scratch_class->inner_classes(); + int icl_length = (inner_class_list == NULL) ? 0 : inner_class_list->length(); + if (icl_length > 0) { + typeArrayHandle inner_class_list_h(THREAD, inner_class_list); + for (int i = 0; i < icl_length; + i += instanceKlass::inner_class_next_offset) { + int cur_index = inner_class_list_h->ushort_at(i + + instanceKlass::inner_class_inner_class_info_offset); + if (cur_index == 0) { + continue; // JVM spec. allows null inner class refs so skip it + } + int new_index = find_new_index(cur_index); + if (new_index != 0) { + RC_TRACE_WITH_THREAD(0x00080000, THREAD, + ("inner_class_info change: %d to %d", cur_index, new_index)); + inner_class_list_h->ushort_at_put(i + + instanceKlass::inner_class_inner_class_info_offset, new_index); + } + cur_index = inner_class_list_h->ushort_at(i + + instanceKlass::inner_class_outer_class_info_offset); + new_index = find_new_index(cur_index); + if (new_index != 0) { + RC_TRACE_WITH_THREAD(0x00080000, THREAD, + ("outer_class_info change: %d to %d", cur_index, new_index)); + inner_class_list_h->ushort_at_put(i + + instanceKlass::inner_class_outer_class_info_offset, new_index); + } + cur_index = inner_class_list_h->ushort_at(i + + instanceKlass::inner_class_inner_name_offset); + new_index = find_new_index(cur_index); + if (new_index != 0) { + RC_TRACE_WITH_THREAD(0x00080000, THREAD, + ("inner_name change: %d to %d", cur_index, new_index)); + inner_class_list_h->ushort_at_put(i + + instanceKlass::inner_class_inner_name_offset, new_index); + } + } // end for each inner class + } // end if we have inner classes + + // Attach each method in klass to the new constant pool and update + // to use new constant pool indices as needed: + objArrayHandle methods(THREAD, scratch_class->methods()); + for (i = methods->length() - 1; i >= 0; i--) { + methodHandle method(THREAD, (methodOop)methods->obj_at(i)); + method->set_constants(scratch_cp()); + + int new_index = find_new_index(method->name_index()); + if (new_index != 0) { + RC_TRACE_WITH_THREAD(0x00080000, THREAD, + ("method-name_index change: %d to %d", method->name_index(), + new_index)); + method->set_name_index(new_index); + } + new_index = find_new_index(method->signature_index()); + if (new_index != 0) { + RC_TRACE_WITH_THREAD(0x00080000, THREAD, + ("method-signature_index change: %d to %d", + method->signature_index(), new_index)); + method->set_signature_index(new_index); + } + new_index = find_new_index(method->generic_signature_index()); + if (new_index != 0) { + RC_TRACE_WITH_THREAD(0x00080000, THREAD, + ("method-generic_signature_index change: %d to %d", + method->generic_signature_index(), new_index)); + method->set_generic_signature_index(new_index); + } + + // Update constant pool indices in the method's checked exception + // table to use new constant indices as needed. + int cext_length = method->checked_exceptions_length(); + if (cext_length > 0) { + CheckedExceptionElement * cext_table = + method->checked_exceptions_start(); + for (int j = 0; j < cext_length; j++) { + int cur_index = cext_table[j].class_cp_index; + int new_index = find_new_index(cur_index); + if (new_index != 0) { + RC_TRACE_WITH_THREAD(0x00080000, THREAD, + ("cext-class_cp_index change: %d to %d", cur_index, new_index)); + cext_table[j].class_cp_index = (u2)new_index; + } + } // end for each checked exception table entry + } // end if there are checked exception table entries + + // Update each catch type index in the method's exception table + // to use new constant pool indices as needed. The exception table + // holds quadruple entries of the form: + // (beg_bci, end_bci, handler_bci, klass_index) + const int beg_bci_offset = 0; + const int end_bci_offset = 1; + const int handler_bci_offset = 2; + const int klass_index_offset = 3; + const int entry_size = 4; + + typeArrayHandle ex_table (THREAD, method->exception_table()); + int ext_length = ex_table->length(); + assert(ext_length % entry_size == 0, "exception table format has changed"); + + for (int j = 0; j < ext_length; j += entry_size) { + int cur_index = ex_table->int_at(j + klass_index_offset); + int new_index = find_new_index(cur_index); + if (new_index != 0) { + RC_TRACE_WITH_THREAD(0x00080000, THREAD, + ("ext-klass_index change: %d to %d", cur_index, new_index)); + ex_table->int_at_put(j + klass_index_offset, new_index); + } + } // end for each exception table entry + + // Update constant pool indices in the method's local variable + // table to use new constant indices as needed. The local variable + // table hold sextuple entries of the form: + // (start_pc, length, name_index, descriptor_index, signature_index, slot) + int lvt_length = method->localvariable_table_length(); + if (lvt_length > 0) { + LocalVariableTableElement * lv_table = + method->localvariable_table_start(); + for (int j = 0; j < lvt_length; j++) { + int cur_index = lv_table[j].name_cp_index; + int new_index = find_new_index(cur_index); + if (new_index != 0) { + RC_TRACE_WITH_THREAD(0x00080000, THREAD, + ("lvt-name_cp_index change: %d to %d", cur_index, new_index)); + lv_table[j].name_cp_index = (u2)new_index; + } + cur_index = lv_table[j].descriptor_cp_index; + new_index = find_new_index(cur_index); + if (new_index != 0) { + RC_TRACE_WITH_THREAD(0x00080000, THREAD, + ("lvt-descriptor_cp_index change: %d to %d", cur_index, + new_index)); + lv_table[j].descriptor_cp_index = (u2)new_index; + } + cur_index = lv_table[j].signature_cp_index; + new_index = find_new_index(cur_index); + if (new_index != 0) { + RC_TRACE_WITH_THREAD(0x00080000, THREAD, + ("lvt-signature_cp_index change: %d to %d", cur_index, new_index)); + lv_table[j].signature_cp_index = (u2)new_index; + } + } // end for each local variable table entry + } // end if there are local variable table entries + + rewrite_cp_refs_in_stack_map_table(method, THREAD); + } // end for each method +} // end set_new_constant_pool() + + +// Unevolving classes may point to methods of the_class 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. +// +// Note: We currently don't support updating the vtable in +// arrayKlassOops. See Open Issues in jvmtiRedefineClasses.hpp. +void VM_RedefineClasses::adjust_cpool_cache_and_vtable(klassOop k_oop, + oop initiating_loader, TRAPS) { + Klass *k = k_oop->klass_part(); + if (k->oop_is_instance()) { + HandleMark hm(THREAD); + instanceKlass *ik = (instanceKlass *) k; + + // HotSpot specific optimization! HotSpot does not currently + // support delegation from the bootstrap class loader to a + // user-defined class loader. This means that if the bootstrap + // class loader is the initiating class loader, then it will also + // be the defining class loader. This also means that classes + // loaded by the bootstrap class loader cannot refer to classes + // loaded by a user-defined class loader. Note: a user-defined + // class loader can delegate to the bootstrap class loader. + // + // If the current class being redefined has a user-defined class + // loader as its defining class loader, then we can skip all + // classes loaded by the bootstrap class loader. + bool is_user_defined = + instanceKlass::cast(_the_class_oop)->class_loader() != NULL; + if (is_user_defined && ik->class_loader() == NULL) { + return; + } + + // This is a very busy routine. We don't want too much tracing + // printed out. + bool trace_name_printed = false; + + // Very noisy: only enable this call if you are trying to determine + // that a specific class gets found by this routine. + // RC_TRACE macro has an embedded ResourceMark + // RC_TRACE_WITH_THREAD(0x00100000, THREAD, + // ("adjust check: name=%s", ik->external_name())); + // trace_name_printed = true; + + // Fix the vtable embedded in the_class and subclasses of the_class, + // if one exists. We discard scratch_class and we don't keep an + // instanceKlass around to hold obsolete methods so we don't have + // any other instanceKlass embedded vtables to update. The vtable + // holds the methodOops for virtual (but not final) methods. + if (ik->vtable_length() > 0 && ik->is_subtype_of(_the_class_oop)) { + // ik->vtable() creates a wrapper object; rm cleans it up + ResourceMark rm(THREAD); + ik->vtable()->adjust_method_entries(_matching_old_methods, + _matching_new_methods, + _matching_methods_length, + &trace_name_printed); + } + + // If the current class has an itable and we are either redefining an + // interface or if the current class is a subclass of the_class, then + // we potentially have to fix the itable. If we are redefining an + // interface, then we have to call adjust_method_entries() for + // every instanceKlass that has an itable since there isn't a + // subclass relationship between an interface and an instanceKlass. + if (ik->itable_length() > 0 && (Klass::cast(_the_class_oop)->is_interface() + || ik->is_subclass_of(_the_class_oop))) { + // ik->itable() creates a wrapper object; rm cleans it up + ResourceMark rm(THREAD); + ik->itable()->adjust_method_entries(_matching_old_methods, + _matching_new_methods, + _matching_methods_length, + &trace_name_printed); + } + + // The constant pools in other classes (other_cp) can refer to + // methods in the_class. We have to update method information in + // other_cp's cache. If other_cp has a previous version, then we + // have to repeat the process for each previous version. The + // constant pool cache holds the methodOops for non-virtual + // methods and for virtual, final methods. + // + // Special case: if the current class is the_class, then new_cp + // has already been attached to the_class and old_cp has already + // been added as a previous version. The new_cp doesn't have any + // cached references to old methods so it doesn't need to be + // updated. We can simply start with the previous version(s) in + // that case. + constantPoolHandle other_cp; + constantPoolCacheOop cp_cache; + + if (k_oop != _the_class_oop) { + // this klass' constant pool cache may need adjustment + other_cp = constantPoolHandle(ik->constants()); + cp_cache = other_cp->cache(); + if (cp_cache != NULL) { + cp_cache->adjust_method_entries(_matching_old_methods, + _matching_new_methods, + _matching_methods_length, + &trace_name_printed); + } + } + { + ResourceMark rm(THREAD); + // PreviousVersionInfo objects returned via PreviousVersionWalker + // contain a GrowableArray of handles. We have to clean up the + // GrowableArray _after_ the PreviousVersionWalker destructor + // has destroyed the handles. + { + // the previous versions' constant pool caches may need adjustment + PreviousVersionWalker pvw(ik); + for (PreviousVersionInfo * pv_info = pvw.next_previous_version(); + pv_info != NULL; pv_info = pvw.next_previous_version()) { + other_cp = pv_info->prev_constant_pool_handle(); + cp_cache = other_cp->cache(); + if (cp_cache != NULL) { + cp_cache->adjust_method_entries(_matching_old_methods, + _matching_new_methods, + _matching_methods_length, + &trace_name_printed); + } + } + } // pvw is cleaned up + } // rm is cleaned up + } +} + +void VM_RedefineClasses::update_jmethod_ids() { + for (int j = 0; j < _matching_methods_length; ++j) { + methodOop old_method = _matching_old_methods[j]; + jmethodID jmid = old_method->find_jmethod_id_or_null(); + if (jmid != NULL) { + // There is a jmethodID, change it to point to the new method + methodHandle new_method_h(_matching_new_methods[j]); + JNIHandles::change_method_associated_with_jmethod_id(jmid, new_method_h); + assert(JNIHandles::resolve_jmethod_id(jmid) == _matching_new_methods[j], + "should be replaced"); + } + } +} + +void VM_RedefineClasses::check_methods_and_mark_as_obsolete( + BitMap *emcp_methods, int * emcp_method_count_p) { + *emcp_method_count_p = 0; + int obsolete_count = 0; + int old_index = 0; + for (int j = 0; j < _matching_methods_length; ++j, ++old_index) { + methodOop old_method = _matching_old_methods[j]; + methodOop new_method = _matching_new_methods[j]; + methodOop old_array_method; + + // Maintain an old_index into the _old_methods array by skipping + // deleted methods + while ((old_array_method = (methodOop) _old_methods->obj_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. + // + // The old and new methods are EMCP and you would think that we + // could get rid of one of them here and now and save some space. + // However, the concept of EMCP only considers the bytecodes and + // the constant pool entries in the comparison. Other things, + // e.g., the line number table (LNT) or the local variable table + // (LVT) don't count in the comparison. So the new (and EMCP) + // method can have a new LNT that we need so we can't just + // overwrite the new method with the old method. + // + // When this routine is called, we have already attached the new + // methods to the_class so the old methods are effectively + // overwritten. However, if an old method is still executing, + // then the old method cannot be collected until sometime after + // the old method call has returned. So the overwriting of old + // methods by new methods will save us space except for those + // (hopefully few) old methods that are still executing. + // + // A method refers to a constMethodOop and this presents another + // possible avenue to space savings. The constMethodOop in the + // new method contains possibly new attributes (LNT, LVT, etc). + // At first glance, it seems possible to save space by replacing + // the constMethodOop in the old method with the constMethodOop + // from the new method. The old and new methods would share the + // same constMethodOop and we would save the space occupied by + // the old constMethodOop. However, the constMethodOop contains + // a back reference to the containing method. Sharing the + // constMethodOop between two methods could lead to confusion in + // the code that uses the back reference. This would lead to + // brittle code that could be broken in non-obvious ways now or + // in the future. + // + // Another possibility is to copy the constMethodOop from the new + // method to the old method and then overwrite the new method with + // the old method. Since the constMethodOop contains the bytecodes + // for the method embedded in the oop, this option would change + // the bytecodes out from under any threads executing the old + // method and make the thread's bcp invalid. Since EMCP requires + // that the bytecodes be the same modulo constant pool indices, it + // is straight forward to compute the correct new bcp in the new + // constMethodOop from the old bcp in the old constMethodOop. The + // time consuming part would be searching all the frames in all + // of the threads to find all of the calls to the old method. + // + // It looks like we will have to live with the limited savings + // that we get from effectively overwriting the old methods + // when the new methods are attached to the_class. + + // 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. + } else { + // mark obsolete methods as such + old_method->set_is_obsolete(); + obsolete_count++; + + // obsolete methods need a unique idnum + u2 num = instanceKlass::cast(_the_class_oop)->next_method_idnum(); + if (num != constMethodOopDesc::UNSET_IDNUM) { +// u2 old_num = old_method->method_idnum(); + old_method->set_method_idnum(num); +// TO DO: attach obsolete annotations to obsolete method's new idnum + } + // 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) { + methodOop old_method = _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)); +} + +// 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_RedefineClasses 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,...) + methodOop search_prefix_name_space(int depth, char* name_str, size_t name_len, + symbolOop signature) { + symbolOop name_symbol = SymbolTable::probe(name_str, (int)name_len); + if (name_symbol != NULL) { + methodOop method = Klass::cast(the_class())->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(methodOop method) { + symbolOop 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. + methodOop strip_and_search_for_new_native(methodOop 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(methodOop* old_methods, int methods_length) { + for (int j = 0; j < methods_length; j++) { + methodOop old_method = old_methods[j]; + + if (old_method->is_native() && old_method->has_native_function()) { + methodOop 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(), + !methodOopDesc::native_bind_event_is_interesting); + } + } + } + } +}; + +// Don't lose the association between a native method and its JNI function. +void VM_RedefineClasses::transfer_old_native_function_registrations(instanceKlassHandle the_class) { + TransferNativeFunctionRegistration transfer(the_class); + transfer.transfer_registrations(_deleted_methods, _deleted_methods_length); + transfer.transfer_registrations(_matching_old_methods, _matching_methods_length); +} + +// 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_RedefineClasses::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 + if (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_RedefineClasses::compute_added_deleted_matching_methods() { + methodOop old_method; + methodOop new_method; + + _matching_old_methods = NEW_RESOURCE_ARRAY(methodOop, _old_methods->length()); + _matching_new_methods = NEW_RESOURCE_ARRAY(methodOop, _old_methods->length()); + _added_methods = NEW_RESOURCE_ARRAY(methodOop, _new_methods->length()); + _deleted_methods = NEW_RESOURCE_ARRAY(methodOop, _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 = (methodOop) _new_methods->obj_at(nj); + _added_methods[_added_methods_length++] = new_method; + ++nj; + } else if (nj >= _new_methods->length()) { + // Old method, at the end, is deleted + old_method = (methodOop) _old_methods->obj_at(oj); + _deleted_methods[_deleted_methods_length++] = old_method; + ++oj; + } else { + old_method = (methodOop) _old_methods->obj_at(oj); + new_method = (methodOop) _new_methods->obj_at(nj); + if (old_method->name() == new_method->name()) { + if (old_method->signature() == new_method->signature()) { + _matching_old_methods[_matching_methods_length ] = old_method; + _matching_new_methods[_matching_methods_length++] = new_method; + ++nj; + ++oj; + } else { + // added overloaded have already been moved to the end, + // so this is a deleted overloaded method + _deleted_methods[_deleted_methods_length++] = 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++] = new_method; + ++nj; + } else { + // deleted method + _deleted_methods[_deleted_methods_length++] = 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"); +} + + + +// Install the redefinition of a class: +// - house keeping (flushing breakpoints and caches, deoptimizing +// dependent compiled code) +// - replacing parts in the_class with parts from scratch_class +// - adding a weak reference to track the obsolete but interesting +// parts of the_class +// - adjusting constant pool caches and vtables in other classes +// that refer to methods in the_class. These adjustments use the +// SystemDictionary::classes_do() facility which only allows +// a helper method to be specified. The interesting parameters +// that we would like to pass to the helper method are saved in +// static global fields in the VM operation. +void VM_RedefineClasses::redefine_single_class(jclass the_jclass, + instanceKlassHandle scratch_class, TRAPS) { + + RC_TIMER_START(_timer_rsc_phase1); + + oop the_class_mirror = JNIHandles::resolve_non_null(the_jclass); + klassOop the_class_oop = java_lang_Class::as_klassOop(the_class_mirror); + instanceKlassHandle the_class = instanceKlassHandle(THREAD, the_class_oop); + +#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_class_oop); +#endif // !JVMTI_KERNEL + + if (the_class_oop == 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_class->method_with_idnum(Universe::reflect_invoke_cache()->method_idnum())); + } + + // Deoptimize all compiled code that depends on this class + flush_dependent_code(the_class, THREAD); + + _old_methods = the_class->methods(); + _new_methods = scratch_class->methods(); + _the_class_oop = the_class_oop; + compute_added_deleted_matching_methods(); + update_jmethod_ids(); + + // Attach new constant pool to the original klass. The original + // klass still refers to the old constant pool (for now). + scratch_class->constants()->set_pool_holder(the_class()); + +#if 0 + // In theory, with constant pool merging in place we should be able + // to save space by using the new, merged constant pool in place of + // the old constant pool(s). By "pool(s)" I mean the constant pool in + // the klass version we are replacing now and any constant pool(s) in + // previous versions of klass. Nice theory, doesn't work in practice. + // When this code is enabled, even simple programs throw NullPointer + // exceptions. I'm guessing that this is caused by some constant pool + // cache difference between the new, merged constant pool and the + // constant pool that was just being used by the klass. I'm keeping + // this code around to archive the idea, but the code has to remain + // disabled for now. + + // Attach each old method to the new constant pool. This can be + // done here since we are past the bytecode verification and + // constant pool optimization phases. + for (int i = _old_methods->length() - 1; i >= 0; i--) { + methodOop method = (methodOop)_old_methods->obj_at(i); + method->set_constants(scratch_class->constants()); + } + + { + // walk all previous versions of the klass + instanceKlass *ik = (instanceKlass *)the_class()->klass_part(); + PreviousVersionWalker pvw(ik); + instanceKlassHandle ikh; + do { + ikh = pvw.next_previous_version(); + if (!ikh.is_null()) { + ik = ikh(); + + // attach previous version of klass to the new constant pool + ik->set_constants(scratch_class->constants()); + + // Attach each method in the previous version of klass to the + // new constant pool + objArrayOop prev_methods = ik->methods(); + for (int i = prev_methods->length() - 1; i >= 0; i--) { + methodOop method = (methodOop)prev_methods->obj_at(i); + method->set_constants(scratch_class->constants()); + } + } + } while (!ikh.is_null()); + } +#endif + + // Replace methods and constantpool + the_class->set_methods(_new_methods); + scratch_class->set_methods(_old_methods); // To prevent potential GCing of the old methods, + // and to be able to undo operation easily. + + constantPoolOop old_constants = the_class->constants(); + the_class->set_constants(scratch_class->constants()); + scratch_class->set_constants(old_constants); // See the previous comment. +#if 0 + // We are swapping the guts of "the new class" with the guts of "the + // class". Since the old constant pool has just been attached to "the + // new class", it seems logical to set the pool holder in the old + // constant pool also. However, doing this will change the observable + // class hierarchy for any old methods that are still executing. A + // method can query the identity of its "holder" and this query uses + // the method's constant pool link to find the holder. The change in + // holding class from "the class" to "the new class" can confuse + // things. + // + // Setting the old constant pool's holder will also cause + // verification done during vtable initialization below to fail. + // During vtable initialization, the vtable's class is verified to be + // a subtype of the method's holder. The vtable's class is "the + // class" and the method's holder is gotten from the constant pool + // link in the method itself. For "the class"'s directly implemented + // methods, the method holder is "the class" itself (as gotten from + // the new constant pool). The check works fine in this case. The + // check also works fine for methods inherited from super classes. + // + // Miranda methods are a little more complicated. A miranda method is + // provided by an interface when the class implementing the interface + // does not provide its own method. These interfaces are implemented + // internally as an instanceKlass. These special instanceKlasses + // share the constant pool of the class that "implements" the + // interface. By sharing the constant pool, the method holder of a + // miranda method is the class that "implements" the interface. In a + // non-redefine situation, the subtype check works fine. However, if + // the old constant pool's pool holder is modified, then the check + // fails because there is no class hierarchy relationship between the + // vtable's class and "the new class". + + old_constants->set_pool_holder(scratch_class()); +#endif + + // track which methods are EMCP for add_previous_version() call below + BitMap emcp_methods(_old_methods->length()); + int emcp_method_count = 0; + emcp_methods.clear(); // clears 0..(length() - 1) + check_methods_and_mark_as_obsolete(&emcp_methods, &emcp_method_count); + transfer_old_native_function_registrations(the_class); + + // The class file bytes from before any retransformable agents mucked + // with them was cached on the scratch class, move to the_class. + // Note: we still want to do this if nothing needed caching since it + // should get cleared in the_class too. + the_class->set_cached_class_file(scratch_class->get_cached_class_file_bytes(), + scratch_class->get_cached_class_file_len()); + + // Replace inner_classes + typeArrayOop old_inner_classes = the_class->inner_classes(); + the_class->set_inner_classes(scratch_class->inner_classes()); + scratch_class->set_inner_classes(old_inner_classes); + + // Initialize the vtable and interface table after + // methods have been rewritten + { + ResourceMark rm(THREAD); + // no exception should happen here since we explicitly + // do not check loader constraints. + // compare_and_normalize_class_versions has already checked: + // - classloaders unchanged, signatures unchanged + // - all instanceKlasses for redefined classes reused & contents updated + the_class->vtable()->initialize_vtable(false, THREAD); + the_class->itable()->initialize_itable(false, THREAD); + assert(!HAS_PENDING_EXCEPTION || (THREAD->pending_exception()->is_a(SystemDictionary::threaddeath_klass())), "redefine exception"); + } + + // Leave arrays of jmethodIDs and itable index cache unchanged + + // Copy the "source file name" attribute from new class version + the_class->set_source_file_name(scratch_class->source_file_name()); + + // Copy the "source debug extension" attribute from new class version + the_class->set_source_debug_extension( + scratch_class->source_debug_extension()); + + // Use of javac -g could be different in the old and the new + if (scratch_class->access_flags().has_localvariable_table() != + the_class->access_flags().has_localvariable_table()) { + + AccessFlags flags = the_class->access_flags(); + if (scratch_class->access_flags().has_localvariable_table()) { + flags.set_has_localvariable_table(); + } else { + flags.clear_has_localvariable_table(); + } + the_class->set_access_flags(flags); + } + + // Replace class annotation fields values + typeArrayOop old_class_annotations = the_class->class_annotations(); + the_class->set_class_annotations(scratch_class->class_annotations()); + scratch_class->set_class_annotations(old_class_annotations); + + // Replace fields annotation fields values + objArrayOop old_fields_annotations = the_class->fields_annotations(); + the_class->set_fields_annotations(scratch_class->fields_annotations()); + scratch_class->set_fields_annotations(old_fields_annotations); + + // Replace methods annotation fields values + objArrayOop old_methods_annotations = the_class->methods_annotations(); + the_class->set_methods_annotations(scratch_class->methods_annotations()); + scratch_class->set_methods_annotations(old_methods_annotations); + + // Replace methods parameter annotation fields values + objArrayOop old_methods_parameter_annotations = + the_class->methods_parameter_annotations(); + the_class->set_methods_parameter_annotations( + scratch_class->methods_parameter_annotations()); + scratch_class->set_methods_parameter_annotations(old_methods_parameter_annotations); + + // Replace methods default annotation fields values + objArrayOop old_methods_default_annotations = + the_class->methods_default_annotations(); + the_class->set_methods_default_annotations( + scratch_class->methods_default_annotations()); + scratch_class->set_methods_default_annotations(old_methods_default_annotations); + + // Replace minor version number of class file + u2 old_minor_version = the_class->minor_version(); + the_class->set_minor_version(scratch_class->minor_version()); + scratch_class->set_minor_version(old_minor_version); + + // Replace major version number of class file + u2 old_major_version = the_class->major_version(); + the_class->set_major_version(scratch_class->major_version()); + scratch_class->set_major_version(old_major_version); + + // Replace CP indexes for class and name+type of enclosing method + u2 old_class_idx = the_class->enclosing_method_class_index(); + u2 old_method_idx = the_class->enclosing_method_method_index(); + the_class->set_enclosing_method_indices( + scratch_class->enclosing_method_class_index(), + scratch_class->enclosing_method_method_index()); + scratch_class->set_enclosing_method_indices(old_class_idx, old_method_idx); + + // keep track of previous versions of this class + the_class->add_previous_version(scratch_class, &emcp_methods, + emcp_method_count); + + RC_TIMER_STOP(_timer_rsc_phase1); + RC_TIMER_START(_timer_rsc_phase2); + + // Adjust constantpool caches and vtables for all classes + // that reference methods of the evolved class. + SystemDictionary::classes_do(adjust_cpool_cache_and_vtable, THREAD); + + if (the_class->oop_map_cache() != NULL) { + // Flush references to any obsolete methods from the oop map cache + // so that obsolete methods are not pinned. + the_class->oop_map_cache()->flush_obsolete_entries(); + } + + // increment the classRedefinedCount field in the_class and in any + // direct and indirect subclasses of the_class + increment_class_counter((instanceKlass *)the_class()->klass_part(), THREAD); + + // RC_TRACE macro has an embedded ResourceMark + RC_TRACE_WITH_THREAD(0x00000001, THREAD, + ("redefined name=%s, count=%d (avail_mem=" UINT64_FORMAT "K)", + the_class->external_name(), + java_lang_Class::classRedefinedCount(the_class_mirror), + os::available_memory() >> 10)); + + RC_TIMER_STOP(_timer_rsc_phase2); +} // end redefine_single_class() + + +// Increment the classRedefinedCount field in the specific instanceKlass +// and in all direct and indirect subclasses. +void VM_RedefineClasses::increment_class_counter(instanceKlass *ik, TRAPS) { + oop class_mirror = ik->java_mirror(); + klassOop class_oop = java_lang_Class::as_klassOop(class_mirror); + int new_count = java_lang_Class::classRedefinedCount(class_mirror) + 1; + java_lang_Class::set_classRedefinedCount(class_mirror, new_count); + + if (class_oop != _the_class_oop) { + // _the_class_oop count is printed at end of redefine_single_class() + RC_TRACE_WITH_THREAD(0x00000008, THREAD, + ("updated count in subclass=%s to %d", ik->external_name(), new_count)); + } + + for (Klass *subk = ik->subklass(); subk != NULL; + subk = subk->next_sibling()) { + klassOop sub = subk->as_klassOop(); + instanceKlass *subik = (instanceKlass *)sub->klass_part(); + + // recursively do subclasses of the current subclass + increment_class_counter(subik, THREAD); + } +} + +#ifndef PRODUCT +void VM_RedefineClasses::check_class(klassOop k_oop, + oop initiating_loader, TRAPS) { + Klass *k = k_oop->klass_part(); + if (k->oop_is_instance()) { + HandleMark hm(THREAD); + instanceKlass *ik = (instanceKlass *) k; + + if (ik->vtable_length() > 0) { + ResourceMark rm(THREAD); + if (!ik->vtable()->check_no_old_entries()) { + tty->print_cr("klassVtable::check_no_old_entries failure -- OLD method found -- class: %s", ik->signature_name()); + ik->vtable()->dump_vtable(); + dump_methods(); + assert(false, "OLD method found"); + } + } + } +} + +void VM_RedefineClasses::dump_methods() { + int j; + tty->print_cr("_old_methods --"); + for (j = 0; j < _old_methods->length(); ++j) { + methodOop m = (methodOop) _old_methods->obj_at(j); + tty->print("%4d (%5d) ", j, m->vtable_index()); + m->access_flags().print_on(tty); + tty->print(" -- "); + m->print_name(tty); + tty->cr(); + } + tty->print_cr("_new_methods --"); + for (j = 0; j < _new_methods->length(); ++j) { + methodOop m = (methodOop) _new_methods->obj_at(j); + tty->print("%4d (%5d) ", j, m->vtable_index()); + m->access_flags().print_on(tty); + tty->print(" -- "); + m->print_name(tty); + tty->cr(); + } + tty->print_cr("_matching_(old/new)_methods --"); + for (j = 0; j < _matching_methods_length; ++j) { + methodOop m = _matching_old_methods[j]; + tty->print("%4d (%5d) ", j, m->vtable_index()); + m->access_flags().print_on(tty); + tty->print(" -- "); + m->print_name(tty); + tty->cr(); + m = _matching_new_methods[j]; + tty->print(" (%5d) ", m->vtable_index()); + m->access_flags().print_on(tty); + tty->cr(); + } + tty->print_cr("_deleted_methods --"); + for (j = 0; j < _deleted_methods_length; ++j) { + methodOop m = _deleted_methods[j]; + tty->print("%4d (%5d) ", j, m->vtable_index()); + m->access_flags().print_on(tty); + tty->print(" -- "); + m->print_name(tty); + tty->cr(); + } + tty->print_cr("_added_methods --"); + for (j = 0; j < _added_methods_length; ++j) { + methodOop m = _added_methods[j]; + tty->print("%4d (%5d) ", j, m->vtable_index()); + m->access_flags().print_on(tty); + tty->print(" -- "); + m->print_name(tty); + tty->cr(); + } +} +#endif