diff -r 4ebc2e2fb97c -r 71c04702a3d5 src/hotspot/share/prims/jvmtiRedefineClasses.cpp --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/hotspot/share/prims/jvmtiRedefineClasses.cpp Tue Sep 12 19:03:39 2017 +0200 @@ -0,0 +1,4226 @@ +/* + * Copyright (c) 2003, 2017, Oracle and/or its affiliates. All rights reserved. + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. + * + * This code is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2 only, as + * published by the Free Software Foundation. + * + * This code is distributed in the hope that it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License + * version 2 for more details (a copy is included in the LICENSE file that + * accompanied this code). + * + * You should have received a copy of the GNU General Public License version + * 2 along with this work; if not, write to the Free Software Foundation, + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. + * + * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA + * or visit www.oracle.com if you need additional information or have any + * questions. + * + */ + +#include "precompiled.hpp" +#include "aot/aotLoader.hpp" +#include "classfile/classFileStream.hpp" +#include "classfile/metadataOnStackMark.hpp" +#include "classfile/systemDictionary.hpp" +#include "classfile/verifier.hpp" +#include "code/codeCache.hpp" +#include "compiler/compileBroker.hpp" +#include "gc/shared/gcLocker.hpp" +#include "interpreter/oopMapCache.hpp" +#include "interpreter/rewriter.hpp" +#include "logging/logStream.hpp" +#include "memory/metadataFactory.hpp" +#include "memory/metaspaceShared.hpp" +#include "memory/resourceArea.hpp" +#include "memory/universe.inline.hpp" +#include "oops/fieldStreams.hpp" +#include "oops/klassVtable.hpp" +#include "oops/oop.inline.hpp" +#include "prims/jvmtiImpl.hpp" +#include "prims/jvmtiRedefineClasses.hpp" +#include "prims/resolvedMethodTable.hpp" +#include "prims/methodComparator.hpp" +#include "runtime/deoptimization.hpp" +#include "runtime/relocator.hpp" +#include "utilities/bitMap.inline.hpp" +#include "utilities/events.hpp" + +Array* VM_RedefineClasses::_old_methods = NULL; +Array* VM_RedefineClasses::_new_methods = NULL; +Method** VM_RedefineClasses::_matching_old_methods = NULL; +Method** VM_RedefineClasses::_matching_new_methods = NULL; +Method** VM_RedefineClasses::_deleted_methods = NULL; +Method** 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; +Klass* VM_RedefineClasses::_the_class = 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; + _any_class_has_resolved_methods = false; + _res = JVMTI_ERROR_NONE; +} + +static inline InstanceKlass* get_ik(jclass def) { + oop mirror = JNIHandles::resolve_non_null(def); + return InstanceKlass::cast(java_lang_Class::as_Klass(mirror)); +} + +// If any of the classes are being redefined, wait +// Parallel constant pool merging leads to indeterminate constant pools. +void VM_RedefineClasses::lock_classes() { + MutexLocker ml(RedefineClasses_lock); + bool has_redefined; + do { + has_redefined = false; + // Go through classes each time until none are being redefined. + for (int i = 0; i < _class_count; i++) { + if (get_ik(_class_defs[i].klass)->is_being_redefined()) { + RedefineClasses_lock->wait(); + has_redefined = true; + break; // for loop + } + } + } while (has_redefined); + for (int i = 0; i < _class_count; i++) { + get_ik(_class_defs[i].klass)->set_is_being_redefined(true); + } + RedefineClasses_lock->notify_all(); +} + +void VM_RedefineClasses::unlock_classes() { + MutexLocker ml(RedefineClasses_lock); + for (int i = 0; i < _class_count; i++) { + assert(get_ik(_class_defs[i].klass)->is_being_redefined(), + "should be being redefined to get here"); + get_ik(_class_defs[i].klass)->set_is_being_redefined(false); + } + RedefineClasses_lock->notify_all(); +} + +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; + } + + oop mirror = JNIHandles::resolve_non_null(_class_defs[i].klass); + // classes for primitives and arrays and vm anonymous classes cannot be redefined + // check here so following code can assume these classes are InstanceKlass + if (!is_modifiable_class(mirror)) { + _res = JVMTI_ERROR_UNMODIFIABLE_CLASS; + return false; + } + } + + // Start timer after all the sanity checks; not quite accurate, but + // better than adding a bunch of stop() calls. + if (log_is_enabled(Info, redefine, class, timer)) { + _timer_vm_op_prologue.start(); + } + + lock_classes(); + // 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 any successfully created classes, since none are redefined + for (int i = 0; i < _class_count; i++) { + if (_scratch_classes[i] != NULL) { + ClassLoaderData* cld = _scratch_classes[i]->class_loader_data(); + // Free the memory for this class at class unloading time. Not before + // because CMS might think this is still live. + cld->add_to_deallocate_list(InstanceKlass::cast(_scratch_classes[i])); + } + } + // Free os::malloc allocated memory in load_new_class_version. + os::free(_scratch_classes); + _timer_vm_op_prologue.stop(); + unlock_classes(); + return false; + } + + _timer_vm_op_prologue.stop(); + return true; +} + +void VM_RedefineClasses::doit() { + Thread *thread = Thread::current(); + +#if INCLUDE_CDS + if (UseSharedSpaces) { + // Sharing is enabled so we remap the shared readonly space to + // shared readwrite, private just in case we need to redefine + // a shared class. We do the remap during the doit() phase of + // the safepoint to be safer. + if (!MetaspaceShared::remap_shared_readonly_as_readwrite()) { + log_info(redefine, class, load)("failed to remap shared readonly space to readwrite, private"); + _res = JVMTI_ERROR_INTERNAL; + return; + } + } +#endif + + // Mark methods seen on stack and everywhere else so old methods are not + // cleaned up if they're on the stack. + MetadataOnStackMark md_on_stack(true); + HandleMark hm(thread); // make sure any handles created are deleted + // before the stack walk again. + + for (int i = 0; i < _class_count; i++) { + redefine_single_class(_class_defs[i].klass, _scratch_classes[i], thread); + } + + // Clean out MethodData pointing to old Method* + // Have to do this after all classes are redefined and all methods that + // are redefined are marked as old. + MethodDataCleaner clean_weak_method_links; + ClassLoaderDataGraph::classes_do(&clean_weak_method_links); + + // JSR-292 support + if (_any_class_has_resolved_methods) { + bool trace_name_printed = false; + ResolvedMethodTable::adjust_method_entries(&trace_name_printed); + } + + // 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(); + + // check_class() is optionally called for product bits, but is + // always called for non-product bits. +#ifdef PRODUCT + if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) { +#endif + log_trace(redefine, class, obsolete, metadata)("calling check_class"); + CheckClass check_class(thread); + ClassLoaderDataGraph::classes_do(&check_class); +#ifdef PRODUCT + } +#endif +} + +void VM_RedefineClasses::doit_epilogue() { + unlock_classes(); + + // Free os::malloc allocated memory. + os::free(_scratch_classes); + + // Reset the_class to null for error printing. + _the_class = NULL; + + if (log_is_enabled(Info, redefine, class, timer)) { + // Used to have separate timers for "doit" and "all", but the timer + // overhead skewed the measurements. + julong doit_time = _timer_rsc_phase1.milliseconds() + + _timer_rsc_phase2.milliseconds(); + julong all_time = _timer_vm_op_prologue.milliseconds() + doit_time; + + log_info(redefine, class, timer) + ("vm_op: all=" JULONG_FORMAT " prologue=" JULONG_FORMAT " doit=" JULONG_FORMAT, + all_time, (julong)_timer_vm_op_prologue.milliseconds(), doit_time); + log_info(redefine, class, timer) + ("redefine_single_class: phase1=" JULONG_FORMAT " phase2=" JULONG_FORMAT, + (julong)_timer_rsc_phase1.milliseconds(), (julong)_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; + } + Klass* k = java_lang_Class::as_Klass(klass_mirror); + // classes for arrays cannot be redefined + if (k == NULL || !k->is_instance_klass()) { + return false; + } + + // Cannot redefine or retransform an anonymous class. + if (InstanceKlass::cast(k)->is_anonymous()) { + 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(const 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. + // + // this is an indirect CP entry so it needs special handling + case JVM_CONSTANT_Class: + case JVM_CONSTANT_UnresolvedClass: + { + int name_i = scratch_cp->klass_name_index_at(scratch_i); + int new_name_i = find_or_append_indirect_entry(scratch_cp, name_i, merge_cp_p, + merge_cp_length_p, THREAD); + + if (new_name_i != name_i) { + log_trace(redefine, class, constantpool) + ("Class entry@%d name_index change: %d to %d", + *merge_cp_length_p, name_i, new_name_i); + } + + (*merge_cp_p)->temp_unresolved_klass_at_put(*merge_cp_length_p, new_name_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: + { + ConstantPool::copy_entry_to(scratch_cp, 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 + // Symbol*s so this entry can be directly appended. + case JVM_CONSTANT_String: // fall through + { + ConstantPool::copy_entry_to(scratch_cp, 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 = find_or_append_indirect_entry(scratch_cp, name_ref_i, merge_cp_p, + merge_cp_length_p, THREAD); + + int signature_ref_i = scratch_cp->signature_ref_index_at(scratch_i); + int new_signature_ref_i = find_or_append_indirect_entry(scratch_cp, signature_ref_i, + merge_cp_p, merge_cp_length_p, + THREAD); + + // 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 != name_ref_i) { + log_trace(redefine, class, constantpool) + ("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 != signature_ref_i) { + log_trace(redefine, class, constantpool) + ("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 = find_or_append_indirect_entry(scratch_cp, klass_ref_i, + merge_cp_p, merge_cp_length_p, THREAD); + + int name_and_type_ref_i = scratch_cp->uncached_name_and_type_ref_index_at(scratch_i); + int new_name_and_type_ref_i = find_or_append_indirect_entry(scratch_cp, name_and_type_ref_i, + merge_cp_p, merge_cp_length_p, THREAD); + + const char *entry_name = NULL; + 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) { + log_trace(redefine, class, constantpool) + ("%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) { + log_trace(redefine, class, constantpool) + ("%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; + + // this is an indirect CP entry so it needs special handling + case JVM_CONSTANT_MethodType: + { + int ref_i = scratch_cp->method_type_index_at(scratch_i); + int new_ref_i = find_or_append_indirect_entry(scratch_cp, ref_i, merge_cp_p, + merge_cp_length_p, THREAD); + if (new_ref_i != ref_i) { + log_trace(redefine, class, constantpool) + ("MethodType entry@%d ref_index change: %d to %d", *merge_cp_length_p, ref_i, new_ref_i); + } + (*merge_cp_p)->method_type_index_at_put(*merge_cp_length_p, new_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 an indirect CP entry so it needs special handling + case JVM_CONSTANT_MethodHandle: + { + int ref_kind = scratch_cp->method_handle_ref_kind_at(scratch_i); + int ref_i = scratch_cp->method_handle_index_at(scratch_i); + int new_ref_i = find_or_append_indirect_entry(scratch_cp, ref_i, merge_cp_p, + merge_cp_length_p, THREAD); + if (new_ref_i != ref_i) { + log_trace(redefine, class, constantpool) + ("MethodHandle entry@%d ref_index change: %d to %d", *merge_cp_length_p, ref_i, new_ref_i); + } + (*merge_cp_p)->method_handle_index_at_put(*merge_cp_length_p, ref_kind, new_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 an indirect CP entry so it needs special handling + case JVM_CONSTANT_InvokeDynamic: + { + // Index of the bootstrap specifier in the operands array + int old_bs_i = scratch_cp->invoke_dynamic_bootstrap_specifier_index(scratch_i); + int new_bs_i = find_or_append_operand(scratch_cp, old_bs_i, merge_cp_p, + merge_cp_length_p, THREAD); + // The bootstrap method NameAndType_info index + int old_ref_i = scratch_cp->invoke_dynamic_name_and_type_ref_index_at(scratch_i); + int new_ref_i = find_or_append_indirect_entry(scratch_cp, old_ref_i, merge_cp_p, + merge_cp_length_p, THREAD); + if (new_bs_i != old_bs_i) { + log_trace(redefine, class, constantpool) + ("InvokeDynamic entry@%d bootstrap_method_attr_index change: %d to %d", + *merge_cp_length_p, old_bs_i, new_bs_i); + } + if (new_ref_i != old_ref_i) { + log_trace(redefine, class, constantpool) + ("InvokeDynamic entry@%d name_and_type_index change: %d to %d", *merge_cp_length_p, old_ref_i, new_ref_i); + } + + (*merge_cp_p)->invoke_dynamic_at_put(*merge_cp_length_p, new_bs_i, new_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 in scratch_cp, 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 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() + + +int VM_RedefineClasses::find_or_append_indirect_entry(const constantPoolHandle& scratch_cp, + int ref_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p, TRAPS) { + + int new_ref_i = ref_i; + bool match = (ref_i < *merge_cp_length_p) && + scratch_cp->compare_entry_to(ref_i, *merge_cp_p, ref_i, THREAD); + + if (!match) { + // forward reference in *merge_cp_p or not a direct match + int found_i = scratch_cp->find_matching_entry(ref_i, *merge_cp_p, THREAD); + if (found_i != 0) { + guarantee(found_i != 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_ref_i = found_i; + map_index(scratch_cp, ref_i, found_i); + } else { + // no match found so we have to append this entry to *merge_cp_p + append_entry(scratch_cp, 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_ref_i = *merge_cp_length_p - 1; + } + } + + return new_ref_i; +} // end find_or_append_indirect_entry() + + +// Append a bootstrap specifier into the merge_cp operands that is semantically equal +// to the scratch_cp operands bootstrap specifier passed by the old_bs_i index. +// Recursively append new merge_cp entries referenced by the new bootstrap specifier. +void VM_RedefineClasses::append_operand(const constantPoolHandle& scratch_cp, int old_bs_i, + constantPoolHandle *merge_cp_p, int *merge_cp_length_p, TRAPS) { + + int old_ref_i = scratch_cp->operand_bootstrap_method_ref_index_at(old_bs_i); + int new_ref_i = find_or_append_indirect_entry(scratch_cp, old_ref_i, merge_cp_p, + merge_cp_length_p, THREAD); + if (new_ref_i != old_ref_i) { + log_trace(redefine, class, constantpool) + ("operands entry@%d bootstrap method ref_index change: %d to %d", _operands_cur_length, old_ref_i, new_ref_i); + } + + Array* merge_ops = (*merge_cp_p)->operands(); + int new_bs_i = _operands_cur_length; + // We have _operands_cur_length == 0 when the merge_cp operands is empty yet. + // However, the operand_offset_at(0) was set in the extend_operands() call. + int new_base = (new_bs_i == 0) ? (*merge_cp_p)->operand_offset_at(0) + : (*merge_cp_p)->operand_next_offset_at(new_bs_i - 1); + int argc = scratch_cp->operand_argument_count_at(old_bs_i); + + ConstantPool::operand_offset_at_put(merge_ops, _operands_cur_length, new_base); + merge_ops->at_put(new_base++, new_ref_i); + merge_ops->at_put(new_base++, argc); + + for (int i = 0; i < argc; i++) { + int old_arg_ref_i = scratch_cp->operand_argument_index_at(old_bs_i, i); + int new_arg_ref_i = find_or_append_indirect_entry(scratch_cp, old_arg_ref_i, merge_cp_p, + merge_cp_length_p, THREAD); + merge_ops->at_put(new_base++, new_arg_ref_i); + if (new_arg_ref_i != old_arg_ref_i) { + log_trace(redefine, class, constantpool) + ("operands entry@%d bootstrap method argument ref_index change: %d to %d", + _operands_cur_length, old_arg_ref_i, new_arg_ref_i); + } + } + if (old_bs_i != _operands_cur_length) { + // The bootstrap specifier in *merge_cp_p is at a different index than + // that in scratch_cp so we need to map the index values. + map_operand_index(old_bs_i, new_bs_i); + } + _operands_cur_length++; +} // end append_operand() + + +int VM_RedefineClasses::find_or_append_operand(const constantPoolHandle& scratch_cp, + int old_bs_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p, TRAPS) { + + int new_bs_i = old_bs_i; // bootstrap specifier index + bool match = (old_bs_i < _operands_cur_length) && + scratch_cp->compare_operand_to(old_bs_i, *merge_cp_p, old_bs_i, THREAD); + + if (!match) { + // forward reference in *merge_cp_p or not a direct match + int found_i = scratch_cp->find_matching_operand(old_bs_i, *merge_cp_p, + _operands_cur_length, THREAD); + if (found_i != -1) { + guarantee(found_i != old_bs_i, "compare_operand_to() and find_matching_operand() disagree"); + // found a matching operand somewhere else in *merge_cp_p so just need a mapping + new_bs_i = found_i; + map_operand_index(old_bs_i, found_i); + } else { + // no match found so we have to append this bootstrap specifier to *merge_cp_p + append_operand(scratch_cp, old_bs_i, merge_cp_p, merge_cp_length_p, THREAD); + new_bs_i = _operands_cur_length - 1; + } + } + return new_bs_i; +} // end find_or_append_operand() + + +void VM_RedefineClasses::finalize_operands_merge(const constantPoolHandle& merge_cp, TRAPS) { + if (merge_cp->operands() == NULL) { + return; + } + // Shrink the merge_cp operands + merge_cp->shrink_operands(_operands_cur_length, CHECK); + + if (log_is_enabled(Trace, redefine, class, constantpool)) { + // don't want to loop unless we are tracing + int count = 0; + for (int i = 1; i < _operands_index_map_p->length(); i++) { + int value = _operands_index_map_p->at(i); + if (value != -1) { + log_trace(redefine, class, constantpool)("operands_index_map[%d]: old=%d new=%d", count, i, value); + count++; + } + } + } + // Clean-up + _operands_index_map_p = NULL; + _operands_cur_length = 0; + _operands_index_map_count = 0; +} // end finalize_operands_merge() + + +jvmtiError VM_RedefineClasses::compare_and_normalize_class_versions( + InstanceKlass* the_class, + InstanceKlass* 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 || + the_class->super()->name() != + 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. + Array* k_interfaces = the_class->local_interfaces(); + Array* 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 (k_interfaces->at(i)->name() != + k_new_interfaces->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. + JavaFieldStream old_fs(the_class); + JavaFieldStream new_fs(scratch_class); + for (; !old_fs.done() && !new_fs.done(); old_fs.next(), new_fs.next()) { + // access + old_flags = old_fs.access_flags().as_short(); + new_flags = new_fs.access_flags().as_short(); + if ((old_flags ^ new_flags) & JVM_RECOGNIZED_FIELD_MODIFIERS) { + return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED; + } + // offset + if (old_fs.offset() != new_fs.offset()) { + return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED; + } + // name and signature + Symbol* name_sym1 = the_class->constants()->symbol_at(old_fs.name_index()); + Symbol* sig_sym1 = the_class->constants()->symbol_at(old_fs.signature_index()); + Symbol* name_sym2 = scratch_class->constants()->symbol_at(new_fs.name_index()); + Symbol* sig_sym2 = scratch_class->constants()->symbol_at(new_fs.signature_index()); + if (name_sym1 != name_sym2 || sig_sym1 != sig_sym2) { + return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED; + } + } + + // If both streams aren't done then we have a differing number of + // fields. + if (!old_fs.done() || !new_fs.done()) { + 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. + Array* k_old_methods(the_class->methods()); + Array* k_new_methods(scratch_class->methods()); + int n_old_methods = k_old_methods->length(); + int n_new_methods = k_new_methods->length(); + Thread* thread = Thread::current(); + + int ni = 0; + int oi = 0; + while (true) { + Method* k_old_method; + Method* k_new_method; + enum { matched, added, deleted, undetermined } method_was = undetermined; + + if (oi >= n_old_methods) { + if (ni >= n_new_methods) { + break; // we've looked at everything, done + } + // New method at the end + k_new_method = k_new_methods->at(ni); + method_was = added; + } else if (ni >= n_new_methods) { + // Old method, at the end, is deleted + k_old_method = k_old_methods->at(oi); + method_was = deleted; + } else { + // There are more methods in both the old and new lists + k_old_method = k_old_methods->at(oi); + k_new_method = k_new_methods->at(ni); + if (k_old_method->name() != k_new_method->name()) { + // Methods are sorted by method name, so a mismatch means added + // or deleted + if (k_old_method->name()->fast_compare(k_new_method->name()) > 0) { + method_was = added; + } else { + method_was = deleted; + } + } else if (k_old_method->signature() == k_new_method->signature()) { + // Both the name and signature match + method_was = matched; + } else { + // The name matches, but the signature doesn't, which means we have to + // search forward through the new overloaded methods. + int nj; // outside the loop for post-loop check + for (nj = ni + 1; nj < n_new_methods; nj++) { + Method* m = k_new_methods->at(nj); + if (k_old_method->name() != m->name()) { + // reached another method name so no more overloaded methods + method_was = deleted; + break; + } + if (k_old_method->signature() == m->signature()) { + // found a match so swap the methods + k_new_methods->at_put(ni, m); + k_new_methods->at_put(nj, k_new_method); + k_new_method = m; + method_was = matched; + break; + } + } + + if (nj >= n_new_methods) { + // reached the end without a match; so method was deleted + method_was = deleted; + } + } + } + + switch (method_was) { + case matched: + // methods match, be sure modifiers do too + old_flags = (jushort) k_old_method->access_flags().get_flags(); + new_flags = (jushort) k_new_method->access_flags().get_flags(); + if ((old_flags ^ new_flags) & ~(JVM_ACC_NATIVE)) { + 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) { + Method* idnum_owner = scratch_class->method_with_idnum(old_num); + if (idnum_owner != NULL) { + // There is already a method assigned this idnum -- switch them + // Take current and original idnum from the new_method + idnum_owner->set_method_idnum(new_num); + idnum_owner->set_orig_method_idnum(k_new_method->orig_method_idnum()); + } + // Take current and original idnum from the old_method + k_new_method->set_method_idnum(old_num); + k_new_method->set_orig_method_idnum(k_old_method->orig_method_idnum()); + if (thread->has_pending_exception()) { + return JVMTI_ERROR_OUT_OF_MEMORY; + } + } + } + log_trace(redefine, class, normalize) + ("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 == ConstMethod::UNSET_IDNUM) { + // cannot add any more methods + return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED; + } + u2 new_num = k_new_method->method_idnum(); + Method* idnum_owner = scratch_class->method_with_idnum(num); + if (idnum_owner != NULL) { + // There is already a method assigned this idnum -- switch them + // Take current and original idnum from the new_method + idnum_owner->set_method_idnum(new_num); + idnum_owner->set_orig_method_idnum(k_new_method->orig_method_idnum()); + } + k_new_method->set_method_idnum(num); + k_new_method->set_orig_method_idnum(num); + if (thread->has_pending_exception()) { + return JVMTI_ERROR_OUT_OF_MEMORY; + } + } + log_trace(redefine, class, normalize) + ("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; + } + log_trace(redefine, class, normalize) + ("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() + + +// Find new bootstrap specifier index value for old bootstrap specifier index +// value by seaching the index map. Returns unused index (-1) if there is +// no mapped value for the old bootstrap specifier index. +int VM_RedefineClasses::find_new_operand_index(int old_index) { + if (_operands_index_map_count == 0) { + // map is empty so nothing can be found + return -1; + } + + if (old_index == -1 || old_index >= _operands_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. + return -1; + } + + int value = _operands_index_map_p->at(old_index); + if (value == -1) { + // the old_index is not mapped + return -1; + } + + return value; +} // end find_new_operand_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(const constantPoolHandle& cp1, + int index1, const 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() + + +jvmtiError VM_RedefineClasses::load_new_class_versions(TRAPS) { + + // For consistency allocate memory using os::malloc wrapper. + _scratch_classes = (InstanceKlass**) + os::malloc(sizeof(InstanceKlass*) * _class_count, mtClass); + if (_scratch_classes == NULL) { + return JVMTI_ERROR_OUT_OF_MEMORY; + } + // Zero initialize the _scratch_classes array. + for (int i = 0; i < _class_count; i++) { + _scratch_classes[i] = NULL; + } + + ResourceMark rm(THREAD); + + JvmtiThreadState *state = JvmtiThreadState::state_for(JavaThread::current()); + // state can only be NULL if the current thread is exiting which + // should not happen since we're trying to do a RedefineClasses + guarantee(state != NULL, "exiting thread calling load_new_class_versions"); + for (int i = 0; i < _class_count; i++) { + // Create HandleMark so that any handles created while loading new class + // versions are deleted. Constant pools are deallocated while merging + // constant pools + HandleMark hm(THREAD); + InstanceKlass* the_class = get_ik(_class_defs[i].klass); + Symbol* the_class_sym = the_class->name(); + + log_debug(redefine, class, load) + ("loading name=%s kind=%d (avail_mem=" UINT64_FORMAT "K)", + the_class->external_name(), _class_load_kind, os::available_memory() >> 10); + + ClassFileStream st((u1*)_class_defs[i].class_bytes, + _class_defs[i].class_byte_count, + "__VM_RedefineClasses__", + ClassFileStream::verify); + + // 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); + + InstanceKlass* scratch_class = 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 + + // Need to clean up allocated InstanceKlass if there's an error so assign + // the result here. Caller deallocates all the scratch classes in case of + // an error. + _scratch_classes[i] = scratch_class; + + if (HAS_PENDING_EXCEPTION) { + Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); + log_info(redefine, class, load, exceptions)("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) { + Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); + log_info(redefine, class, load, exceptions)("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, true, THREAD); + } + + if (HAS_PENDING_EXCEPTION) { + Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); + log_info(redefine, class, load, exceptions)("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 (HAS_PENDING_EXCEPTION) { + Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); + log_info(redefine, class, load, exceptions)("merge_cp_and_rewrite 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; + } + } + + if (VerifyMergedCPBytecodes) { + // verify what we have done during constant pool merging + { + RedefineVerifyMark rvm(the_class, scratch_class, state); + Verifier::verify(scratch_class, Verifier::ThrowException, true, THREAD); + } + + if (HAS_PENDING_EXCEPTION) { + Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); + log_info(redefine, class, load, exceptions) + ("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) { + scratch_class->link_methods(THREAD); + } + if (HAS_PENDING_EXCEPTION) { + Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); + log_info(redefine, class, load, exceptions) + ("Rewriter::rewrite or link_methods 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; + } + } + + log_debug(redefine, class, load) + ("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 log calls. +void VM_RedefineClasses::map_index(const 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++; + + log_trace(redefine, class, constantpool) + ("mapped tag %d at index %d to %d", scratch_cp->tag_at(old_index).value(), old_index, new_index); +} // end map_index() + + +// Map old_index to new_index as needed. +void VM_RedefineClasses::map_operand_index(int old_index, int new_index) { + if (find_new_operand_index(old_index) != -1) { + // old_index is already mapped + return; + } + + if (old_index == new_index) { + // no mapping is needed + return; + } + + _operands_index_map_p->at_put(old_index, new_index); + _operands_index_map_count++; + + log_trace(redefine, class, constantpool)("mapped bootstrap specifier at index %d to %d", 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(const constantPoolHandle& old_cp, + const constantPoolHandle& scratch_cp, constantPoolHandle *merge_cp_p, + int *merge_cp_length_p, TRAPS) { + + if (merge_cp_p == NULL) { + assert(false, "caller must provide scratch constantPool"); + return false; // robustness + } + if (merge_cp_length_p == NULL) { + assert(false, "caller must provide scratch 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 + } + + log_info(redefine, class, constantpool)("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 ConstantPool*::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: + case JVM_CONSTANT_UnresolvedClass: + // revert the copy to JVM_CONSTANT_UnresolvedClass + // May be resolving while calling this so do the same for + // JVM_CONSTANT_UnresolvedClass (klass_name_at() deals with transition) + (*merge_cp_p)->temp_unresolved_klass_at_put(old_i, + old_cp->klass_name_index_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 + ConstantPool::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i, CHECK_0); + old_i++; + break; + + default: + // just copy the entry to *merge_cp_p + ConstantPool::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i, CHECK_0); + break; + } + } // end for each old_cp entry + + ConstantPool::copy_operands(old_cp, *merge_cp_p, CHECK_0); + (*merge_cp_p)->extend_operands(scratch_cp, CHECK_0); + + // 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. + log_debug(redefine, class, constantpool)("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; + } + + 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); + } + } + + log_debug(redefine, class, constantpool) + ("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); + } + + log_debug(redefine, class, constantpool) + ("after pass 1b: merge_cp_len=%d, scratch_i=%d, index_map_len=%d", + *merge_cp_length_p, scratch_i, _index_map_count); + } + finalize_operands_merge(*merge_cp_p, THREAD); + + return true; +} // end merge_constant_pools() + + +// Scoped object to clean up the constant pool(s) created for merging +class MergeCPCleaner { + ClassLoaderData* _loader_data; + ConstantPool* _cp; + ConstantPool* _scratch_cp; + public: + MergeCPCleaner(ClassLoaderData* loader_data, ConstantPool* merge_cp) : + _loader_data(loader_data), _cp(merge_cp), _scratch_cp(NULL) {} + ~MergeCPCleaner() { + _loader_data->add_to_deallocate_list(_cp); + if (_scratch_cp != NULL) { + _loader_data->add_to_deallocate_list(_scratch_cp); + } + } + void add_scratch_cp(ConstantPool* scratch_cp) { _scratch_cp = scratch_cp; } +}; + +// 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( + InstanceKlass* the_class, InstanceKlass* 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(); + + // Constant pools are not easily reused so we allocate a new one + // each time. + // merge_cp is created unsafe for concurrent GC processing. It + // should be marked safe before discarding it. Even though + // garbage, if it crosses a card boundary, it may be scanned + // in order to find the start of the first complete object on the card. + ClassLoaderData* loader_data = the_class->class_loader_data(); + ConstantPool* merge_cp_oop = + ConstantPool::allocate(loader_data, + merge_cp_length, + CHECK_(JVMTI_ERROR_OUT_OF_MEMORY)); + MergeCPCleaner cp_cleaner(loader_data, merge_cp_oop); + + HandleMark hm(THREAD); // make sure handles are cleared before + // MergeCPCleaner clears out merge_cp_oop + constantPoolHandle merge_cp(THREAD, merge_cp_oop); + + // Get constants() from the old class because it could have been rewritten + // while we were at a safepoint allocating a new constant pool. + constantPoolHandle old_cp(THREAD, the_class->constants()); + constantPoolHandle scratch_cp(THREAD, scratch_class->constants()); + + // If the length changed, the class was redefined out from under us. Return + // an error. + if (merge_cp_length != the_class->constants()->length() + + scratch_class->constants()->length()) { + return JVMTI_ERROR_INTERNAL; + } + + // Update the version number of the constant pools (may keep scratch_cp) + merge_cp->increment_and_save_version(old_cp->version()); + scratch_cp->increment_and_save_version(old_cp->version()); + + ResourceMark rm(THREAD); + _index_map_count = 0; + _index_map_p = new intArray(scratch_cp->length(), scratch_cp->length(), -1); + + _operands_cur_length = ConstantPool::operand_array_length(old_cp->operands()); + _operands_index_map_count = 0; + int operands_index_map_len = ConstantPool::operand_array_length(scratch_cp->operands()); + _operands_index_map_p = new intArray(operands_index_map_len, operands_index_map_len, -1); + + // reference to the cp holder is needed for copy_operands() + merge_cp->set_pool_holder(scratch_class); + bool result = merge_constant_pools(old_cp, scratch_cp, &merge_cp, + &merge_cp_length, THREAD); + merge_cp->set_pool_holder(NULL); + + if (!result) { + // The merge can fail due to memory allocation failure or due + // to robustness checks. + return JVMTI_ERROR_INTERNAL; + } + + log_info(redefine, class, constantpool)("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. + + // toss the merged constant pool at return + } 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. + + // toss the merged constant pool at return + } 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 + set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length, + CHECK_(JVMTI_ERROR_OUT_OF_MEMORY)); + // The new constant pool replaces scratch_cp so have cleaner clean it up. + // It can't be cleaned up while there are handles to it. + cp_cleaner.add_scratch_cp(scratch_cp()); + } + } else { + if (log_is_enabled(Trace, redefine, class, constantpool)) { + // 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) { + log_trace(redefine, class, constantpool)("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(loader_data, scratch_class, merge_cp, merge_cp_length, + CHECK_(JVMTI_ERROR_OUT_OF_MEMORY)); + // The new constant pool replaces scratch_cp so have cleaner clean it up. + // It can't be cleaned up while there are handles to it. + cp_cleaner.add_scratch_cp(scratch_cp()); + } + + return JVMTI_ERROR_NONE; +} // end merge_cp_and_rewrite() + + +// Rewrite constant pool references in klass scratch_class. +bool VM_RedefineClasses::rewrite_cp_refs(InstanceKlass* scratch_class, + TRAPS) { + + // rewrite constant pool references in the methods: + if (!rewrite_cp_refs_in_methods(scratch_class, THREAD)) { + // propagate failure back to caller + return false; + } + + // rewrite constant pool references in the class_annotations: + if (!rewrite_cp_refs_in_class_annotations(scratch_class, THREAD)) { + // propagate failure back to caller + return false; + } + + // rewrite constant pool references in the fields_annotations: + if (!rewrite_cp_refs_in_fields_annotations(scratch_class, THREAD)) { + // propagate failure back to caller + return false; + } + + // rewrite constant pool references in the methods_annotations: + if (!rewrite_cp_refs_in_methods_annotations(scratch_class, THREAD)) { + // propagate 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)) { + // propagate 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)) { + // propagate failure back to caller + return false; + } + + // rewrite constant pool references in the class_type_annotations: + if (!rewrite_cp_refs_in_class_type_annotations(scratch_class, THREAD)) { + // propagate failure back to caller + return false; + } + + // rewrite constant pool references in the fields_type_annotations: + if (!rewrite_cp_refs_in_fields_type_annotations(scratch_class, THREAD)) { + // propagate failure back to caller + return false; + } + + // rewrite constant pool references in the methods_type_annotations: + if (!rewrite_cp_refs_in_methods_type_annotations(scratch_class, THREAD)) { + // propagate failure back to caller + return false; + } + + // There can be type annotations in the Code part of a method_info attribute. + // These annotations are not accessible, even by reflection. + // Currently they are not even parsed by the ClassFileParser. + // If runtime access is added they will also need to be rewritten. + + // rewrite source file name index: + u2 source_file_name_idx = scratch_class->source_file_name_index(); + if (source_file_name_idx != 0) { + u2 new_source_file_name_idx = find_new_index(source_file_name_idx); + if (new_source_file_name_idx != 0) { + scratch_class->set_source_file_name_index(new_source_file_name_idx); + } + } + + // rewrite class generic signature index: + u2 generic_signature_index = scratch_class->generic_signature_index(); + if (generic_signature_index != 0) { + u2 new_generic_signature_index = find_new_index(generic_signature_index); + if (new_generic_signature_index != 0) { + scratch_class->set_generic_signature_index(new_generic_signature_index); + } + } + + return true; +} // end rewrite_cp_refs() + +// Rewrite constant pool references in the methods. +bool VM_RedefineClasses::rewrite_cp_refs_in_methods( + InstanceKlass* scratch_class, TRAPS) { + + Array* methods = scratch_class->methods(); + + if (methods == 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, methods->at(i)); + methodHandle new_method; + rewrite_cp_refs_in_method(method, &new_method, THREAD); + if (!new_method.is_null()) { + // the method has been replaced so save the new method version + // even in the case of an exception. original method is on the + // deallocation list. + methods->at_put(i, new_method()); + } + if (HAS_PENDING_EXCEPTION) { + Symbol* ex_name = PENDING_EXCEPTION->klass()->name(); + log_info(redefine, class, load, exceptions)("rewrite_cp_refs_in_method exception: '%s'", ex_name->as_C_string()); + // Need to clear pending exception here as the super caller sets + // the JVMTI_ERROR_INTERNAL if the returned value is false. + CLEAR_PENDING_EXCEPTION; + return false; + } + } + + 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 Method*, then the bytecodes will also move which + // will likely cause a crash. We create a NoSafepointVerifier + // object to detect whether we pass a possible safepoint in this + // code block. + NoSafepointVerifier 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(method(), 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 + log_trace(redefine, class, constantpool) + ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c), p2i(bcp), cp_index, new_index); + *(bcp + 1) = new_index; + } else { + log_trace(redefine, class, constantpool) + ("%s->ldc_w@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c), p2i(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; + { + PauseNoSafepointVerifier pnsv(&nsv); + + // ldc is 2 bytes and ldc_w is 3 bytes + m = rc.insert_space_at(bci, 3, inst_buffer, CHECK); + } + + // 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::_invokedynamic : // 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 + log_trace(redefine, class, constantpool) + ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c),p2i(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; + default: + break; + } + } // end for each bytecode + + // We also need to rewrite the parameter name indexes, if there is + // method parameter data present + if(method->has_method_parameters()) { + const int len = method->method_parameters_length(); + MethodParametersElement* elem = method->method_parameters_start(); + + for (int i = 0; i < len; i++) { + const u2 cp_index = elem[i].name_cp_index; + const u2 new_cp_index = find_new_index(cp_index); + if (new_cp_index != 0) { + elem[i].name_cp_index = new_cp_index; + } + } + } +} // end rewrite_cp_refs_in_method() + + +// Rewrite constant pool references in the class_annotations field. +bool VM_RedefineClasses::rewrite_cp_refs_in_class_annotations( + InstanceKlass* scratch_class, TRAPS) { + + AnnotationArray* class_annotations = scratch_class->class_annotations(); + if (class_annotations == NULL || class_annotations->length() == 0) { + // no class_annotations so nothing to do + return true; + } + + log_debug(redefine, class, annotation)("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( + AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) { + + if ((byte_i_ref + 2) > annotations_typeArray->length()) { + // not enough room for num_annotations field + log_debug(redefine, class, annotation)("length() is too small for num_annotations field"); + return false; + } + + u2 num_annotations = Bytes::get_Java_u2((address) + annotations_typeArray->adr_at(byte_i_ref)); + byte_i_ref += 2; + + log_debug(redefine, class, annotation)("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)) { + log_debug(redefine, class, annotation)("bad annotation_struct at %d", calc_num_annotations); + // propagate 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( + AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) { + if ((byte_i_ref + 2 + 2) > annotations_typeArray->length()) { + // not enough room for smallest annotation_struct + log_debug(redefine, class, annotation)("length() is too small for annotation_struct"); + return false; + } + + u2 type_index = rewrite_cp_ref_in_annotation_data(annotations_typeArray, + byte_i_ref, "type_index", THREAD); + + u2 num_element_value_pairs = Bytes::get_Java_u2((address) + annotations_typeArray->adr_at(byte_i_ref)); + byte_i_ref += 2; + + log_debug(redefine, class, annotation) + ("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 + log_debug(redefine, class, annotation)("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, + "element_name_index", THREAD); + + log_debug(redefine, class, annotation)("element_name_index=%d", element_name_index); + + if (!rewrite_cp_refs_in_element_value(annotations_typeArray, + byte_i_ref, THREAD)) { + log_debug(redefine, class, annotation)("bad element_value at %d", calc_num_element_value_pairs); + // propagate 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( + AnnotationArray* annotations_typeArray, int &byte_i_ref, + const char * trace_mesg, TRAPS) { + + address cp_index_addr = (address) + annotations_typeArray->adr_at(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) { + log_debug(redefine, class, annotation)("mapped old %s=%d", 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( + AnnotationArray* 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 + log_debug(redefine, class, annotation)("length() is too small for a tag"); + return false; + } + + u1 tag = annotations_typeArray->at(byte_i_ref); + byte_i_ref++; + log_debug(redefine, class, annotation)("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 + log_debug(redefine, class, annotation)("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, + "const_value_index", THREAD); + + log_debug(redefine, class, annotation)("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 + log_debug(redefine, class, annotation)("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, + "type_name_index", THREAD); + + u2 const_name_index = rewrite_cp_ref_in_annotation_data( + annotations_typeArray, byte_i_ref, + "const_name_index", THREAD); + + log_debug(redefine, class, annotation) + ("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 + log_debug(redefine, class, annotation)("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, + "class_info_index", THREAD); + + log_debug(redefine, class, annotation)("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)) { + // propagate failure back to caller + return false; + } + break; + + case '[': + { + if ((byte_i_ref + 2) > annotations_typeArray->length()) { + // not enough room for a num_values field + log_debug(redefine, class, annotation)("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->adr_at(byte_i_ref)); + byte_i_ref += 2; + log_debug(redefine, class, annotation)("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)) { + log_debug(redefine, class, annotation)("bad nested element_value at %d", calc_num_values); + // propagate failure back to caller + return false; + } + } + assert(num_values == calc_num_values, "sanity check"); + } break; + + default: + log_debug(redefine, class, annotation)("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( + InstanceKlass* scratch_class, TRAPS) { + + Array* fields_annotations = scratch_class->fields_annotations(); + + if (fields_annotations == NULL || fields_annotations->length() == 0) { + // no fields_annotations so nothing to do + return true; + } + + log_debug(redefine, class, annotation)("fields_annotations length=%d", fields_annotations->length()); + + for (int i = 0; i < fields_annotations->length(); i++) { + AnnotationArray* field_annotations = fields_annotations->at(i); + if (field_annotations == 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)) { + log_debug(redefine, class, annotation)("bad field_annotations at %d", i); + // propagate 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( + InstanceKlass* scratch_class, TRAPS) { + + for (int i = 0; i < scratch_class->methods()->length(); i++) { + Method* m = scratch_class->methods()->at(i); + AnnotationArray* method_annotations = m->constMethod()->method_annotations(); + + if (method_annotations == 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)) { + log_debug(redefine, class, annotation)("bad method_annotations at %d", i); + // propagate 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( + InstanceKlass* scratch_class, TRAPS) { + + for (int i = 0; i < scratch_class->methods()->length(); i++) { + Method* m = scratch_class->methods()->at(i); + AnnotationArray* method_parameter_annotations = m->constMethod()->parameter_annotations(); + if (method_parameter_annotations == 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 + log_debug(redefine, class, annotation)("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->at(byte_i); + byte_i++; + + log_debug(redefine, class, annotation)("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)) { + log_debug(redefine, class, annotation)("bad method_parameter_annotations at %d", calc_num_parameters); + // propagate 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( + InstanceKlass* scratch_class, TRAPS) { + + for (int i = 0; i < scratch_class->methods()->length(); i++) { + Method* m = scratch_class->methods()->at(i); + AnnotationArray* method_default_annotations = m->constMethod()->default_annotations(); + if (method_default_annotations == 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)) { + log_debug(redefine, class, annotation)("bad default element_value at %d", i); + // propagate failure back to caller + return false; + } + } + + return true; +} // end rewrite_cp_refs_in_methods_default_annotations() + + +// Rewrite constant pool references in a class_type_annotations field. +bool VM_RedefineClasses::rewrite_cp_refs_in_class_type_annotations( + InstanceKlass* scratch_class, TRAPS) { + + AnnotationArray* class_type_annotations = scratch_class->class_type_annotations(); + if (class_type_annotations == NULL || class_type_annotations->length() == 0) { + // no class_type_annotations so nothing to do + return true; + } + + log_debug(redefine, class, annotation)("class_type_annotations length=%d", class_type_annotations->length()); + + int byte_i = 0; // byte index into class_type_annotations + return rewrite_cp_refs_in_type_annotations_typeArray(class_type_annotations, + byte_i, "ClassFile", THREAD); +} // end rewrite_cp_refs_in_class_type_annotations() + + +// Rewrite constant pool references in a fields_type_annotations field. +bool VM_RedefineClasses::rewrite_cp_refs_in_fields_type_annotations( + InstanceKlass* scratch_class, TRAPS) { + + Array* fields_type_annotations = scratch_class->fields_type_annotations(); + if (fields_type_annotations == NULL || fields_type_annotations->length() == 0) { + // no fields_type_annotations so nothing to do + return true; + } + + log_debug(redefine, class, annotation)("fields_type_annotations length=%d", fields_type_annotations->length()); + + for (int i = 0; i < fields_type_annotations->length(); i++) { + AnnotationArray* field_type_annotations = fields_type_annotations->at(i); + if (field_type_annotations == NULL || field_type_annotations->length() == 0) { + // this field does not have any annotations so skip it + continue; + } + + int byte_i = 0; // byte index into field_type_annotations + if (!rewrite_cp_refs_in_type_annotations_typeArray(field_type_annotations, + byte_i, "field_info", THREAD)) { + log_debug(redefine, class, annotation)("bad field_type_annotations at %d", i); + // propagate failure back to caller + return false; + } + } + + return true; +} // end rewrite_cp_refs_in_fields_type_annotations() + + +// Rewrite constant pool references in a methods_type_annotations field. +bool VM_RedefineClasses::rewrite_cp_refs_in_methods_type_annotations( + InstanceKlass* scratch_class, TRAPS) { + + for (int i = 0; i < scratch_class->methods()->length(); i++) { + Method* m = scratch_class->methods()->at(i); + AnnotationArray* method_type_annotations = m->constMethod()->type_annotations(); + + if (method_type_annotations == NULL || method_type_annotations->length() == 0) { + // this method does not have any annotations so skip it + continue; + } + + log_debug(redefine, class, annotation)("methods type_annotations length=%d", method_type_annotations->length()); + + int byte_i = 0; // byte index into method_type_annotations + if (!rewrite_cp_refs_in_type_annotations_typeArray(method_type_annotations, + byte_i, "method_info", THREAD)) { + log_debug(redefine, class, annotation)("bad method_type_annotations at %d", i); + // propagate failure back to caller + return false; + } + } + + return true; +} // end rewrite_cp_refs_in_methods_type_annotations() + + +// Rewrite constant pool references in a type_annotations +// field. This "structure" is adapted from the +// RuntimeVisibleTypeAnnotations_attribute described in +// section 4.7.20 of the Java SE 8 Edition of the VM spec: +// +// type_annotations_typeArray { +// u2 num_annotations; +// type_annotation annotations[num_annotations]; +// } +// +bool VM_RedefineClasses::rewrite_cp_refs_in_type_annotations_typeArray( + AnnotationArray* type_annotations_typeArray, int &byte_i_ref, + const char * location_mesg, TRAPS) { + + if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { + // not enough room for num_annotations field + log_debug(redefine, class, annotation)("length() is too small for num_annotations field"); + return false; + } + + u2 num_annotations = Bytes::get_Java_u2((address) + type_annotations_typeArray->adr_at(byte_i_ref)); + byte_i_ref += 2; + + log_debug(redefine, class, annotation)("num_type_annotations=%d", num_annotations); + + int calc_num_annotations = 0; + for (; calc_num_annotations < num_annotations; calc_num_annotations++) { + if (!rewrite_cp_refs_in_type_annotation_struct(type_annotations_typeArray, + byte_i_ref, location_mesg, THREAD)) { + log_debug(redefine, class, annotation)("bad type_annotation_struct at %d", calc_num_annotations); + // propagate failure back to caller + return false; + } + } + assert(num_annotations == calc_num_annotations, "sanity check"); + + if (byte_i_ref != type_annotations_typeArray->length()) { + log_debug(redefine, class, annotation) + ("read wrong amount of bytes at end of processing type_annotations_typeArray (%d of %d bytes were read)", + byte_i_ref, type_annotations_typeArray->length()); + return false; + } + + return true; +} // end rewrite_cp_refs_in_type_annotations_typeArray() + + +// Rewrite constant pool references in a type_annotation +// field. This "structure" is adapted from the +// RuntimeVisibleTypeAnnotations_attribute described in +// section 4.7.20 of the Java SE 8 Edition of the VM spec: +// +// type_annotation { +// u1 target_type; +// union { +// type_parameter_target; +// supertype_target; +// type_parameter_bound_target; +// empty_target; +// method_formal_parameter_target; +// throws_target; +// localvar_target; +// catch_target; +// offset_target; +// type_argument_target; +// } target_info; +// type_path target_path; +// annotation anno; +// } +// +bool VM_RedefineClasses::rewrite_cp_refs_in_type_annotation_struct( + AnnotationArray* type_annotations_typeArray, int &byte_i_ref, + const char * location_mesg, TRAPS) { + + if (!skip_type_annotation_target(type_annotations_typeArray, + byte_i_ref, location_mesg, THREAD)) { + return false; + } + + if (!skip_type_annotation_type_path(type_annotations_typeArray, + byte_i_ref, THREAD)) { + return false; + } + + if (!rewrite_cp_refs_in_annotation_struct(type_annotations_typeArray, + byte_i_ref, THREAD)) { + return false; + } + + return true; +} // end rewrite_cp_refs_in_type_annotation_struct() + + +// Read, verify and skip over the target_type and target_info part +// so that rewriting can continue in the later parts of the struct. +// +// u1 target_type; +// union { +// type_parameter_target; +// supertype_target; +// type_parameter_bound_target; +// empty_target; +// method_formal_parameter_target; +// throws_target; +// localvar_target; +// catch_target; +// offset_target; +// type_argument_target; +// } target_info; +// +bool VM_RedefineClasses::skip_type_annotation_target( + AnnotationArray* type_annotations_typeArray, int &byte_i_ref, + const char * location_mesg, TRAPS) { + + if ((byte_i_ref + 1) > type_annotations_typeArray->length()) { + // not enough room for a target_type let alone the rest of a type_annotation + log_debug(redefine, class, annotation)("length() is too small for a target_type"); + return false; + } + + u1 target_type = type_annotations_typeArray->at(byte_i_ref); + byte_i_ref += 1; + log_debug(redefine, class, annotation)("target_type=0x%.2x", target_type); + log_debug(redefine, class, annotation)("location=%s", location_mesg); + + // Skip over target_info + switch (target_type) { + case 0x00: + // kind: type parameter declaration of generic class or interface + // location: ClassFile + case 0x01: + // kind: type parameter declaration of generic method or constructor + // location: method_info + + { + // struct: + // type_parameter_target { + // u1 type_parameter_index; + // } + // + if ((byte_i_ref + 1) > type_annotations_typeArray->length()) { + log_debug(redefine, class, annotation)("length() is too small for a type_parameter_target"); + return false; + } + + u1 type_parameter_index = type_annotations_typeArray->at(byte_i_ref); + byte_i_ref += 1; + + log_debug(redefine, class, annotation)("type_parameter_target: type_parameter_index=%d", type_parameter_index); + } break; + + case 0x10: + // kind: type in extends clause of class or interface declaration + // (including the direct superclass of an anonymous class declaration), + // or in implements clause of interface declaration + // location: ClassFile + + { + // struct: + // supertype_target { + // u2 supertype_index; + // } + // + if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { + log_debug(redefine, class, annotation)("length() is too small for a supertype_target"); + return false; + } + + u2 supertype_index = Bytes::get_Java_u2((address) + type_annotations_typeArray->adr_at(byte_i_ref)); + byte_i_ref += 2; + + log_debug(redefine, class, annotation)("supertype_target: supertype_index=%d", supertype_index); + } break; + + case 0x11: + // kind: type in bound of type parameter declaration of generic class or interface + // location: ClassFile + case 0x12: + // kind: type in bound of type parameter declaration of generic method or constructor + // location: method_info + + { + // struct: + // type_parameter_bound_target { + // u1 type_parameter_index; + // u1 bound_index; + // } + // + if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { + log_debug(redefine, class, annotation)("length() is too small for a type_parameter_bound_target"); + return false; + } + + u1 type_parameter_index = type_annotations_typeArray->at(byte_i_ref); + byte_i_ref += 1; + u1 bound_index = type_annotations_typeArray->at(byte_i_ref); + byte_i_ref += 1; + + log_debug(redefine, class, annotation) + ("type_parameter_bound_target: type_parameter_index=%d, bound_index=%d", type_parameter_index, bound_index); + } break; + + case 0x13: + // kind: type in field declaration + // location: field_info + case 0x14: + // kind: return type of method, or type of newly constructed object + // location: method_info + case 0x15: + // kind: receiver type of method or constructor + // location: method_info + + { + // struct: + // empty_target { + // } + // + log_debug(redefine, class, annotation)("empty_target"); + } break; + + case 0x16: + // kind: type in formal parameter declaration of method, constructor, or lambda expression + // location: method_info + + { + // struct: + // formal_parameter_target { + // u1 formal_parameter_index; + // } + // + if ((byte_i_ref + 1) > type_annotations_typeArray->length()) { + log_debug(redefine, class, annotation)("length() is too small for a formal_parameter_target"); + return false; + } + + u1 formal_parameter_index = type_annotations_typeArray->at(byte_i_ref); + byte_i_ref += 1; + + log_debug(redefine, class, annotation) + ("formal_parameter_target: formal_parameter_index=%d", formal_parameter_index); + } break; + + case 0x17: + // kind: type in throws clause of method or constructor + // location: method_info + + { + // struct: + // throws_target { + // u2 throws_type_index + // } + // + if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { + log_debug(redefine, class, annotation)("length() is too small for a throws_target"); + return false; + } + + u2 throws_type_index = Bytes::get_Java_u2((address) + type_annotations_typeArray->adr_at(byte_i_ref)); + byte_i_ref += 2; + + log_debug(redefine, class, annotation)("throws_target: throws_type_index=%d", throws_type_index); + } break; + + case 0x40: + // kind: type in local variable declaration + // location: Code + case 0x41: + // kind: type in resource variable declaration + // location: Code + + { + // struct: + // localvar_target { + // u2 table_length; + // struct { + // u2 start_pc; + // u2 length; + // u2 index; + // } table[table_length]; + // } + // + if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { + // not enough room for a table_length let alone the rest of a localvar_target + log_debug(redefine, class, annotation)("length() is too small for a localvar_target table_length"); + return false; + } + + u2 table_length = Bytes::get_Java_u2((address) + type_annotations_typeArray->adr_at(byte_i_ref)); + byte_i_ref += 2; + + log_debug(redefine, class, annotation)("localvar_target: table_length=%d", table_length); + + int table_struct_size = 2 + 2 + 2; // 3 u2 variables per table entry + int table_size = table_length * table_struct_size; + + if ((byte_i_ref + table_size) > type_annotations_typeArray->length()) { + // not enough room for a table + log_debug(redefine, class, annotation)("length() is too small for a table array of length %d", table_length); + return false; + } + + // Skip over table + byte_i_ref += table_size; + } break; + + case 0x42: + // kind: type in exception parameter declaration + // location: Code + + { + // struct: + // catch_target { + // u2 exception_table_index; + // } + // + if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { + log_debug(redefine, class, annotation)("length() is too small for a catch_target"); + return false; + } + + u2 exception_table_index = Bytes::get_Java_u2((address) + type_annotations_typeArray->adr_at(byte_i_ref)); + byte_i_ref += 2; + + log_debug(redefine, class, annotation)("catch_target: exception_table_index=%d", exception_table_index); + } break; + + case 0x43: + // kind: type in instanceof expression + // location: Code + case 0x44: + // kind: type in new expression + // location: Code + case 0x45: + // kind: type in method reference expression using ::new + // location: Code + case 0x46: + // kind: type in method reference expression using ::Identifier + // location: Code + + { + // struct: + // offset_target { + // u2 offset; + // } + // + if ((byte_i_ref + 2) > type_annotations_typeArray->length()) { + log_debug(redefine, class, annotation)("length() is too small for a offset_target"); + return false; + } + + u2 offset = Bytes::get_Java_u2((address) + type_annotations_typeArray->adr_at(byte_i_ref)); + byte_i_ref += 2; + + log_debug(redefine, class, annotation)("offset_target: offset=%d", offset); + } break; + + case 0x47: + // kind: type in cast expression + // location: Code + case 0x48: + // kind: type argument for generic constructor in new expression or + // explicit constructor invocation statement + // location: Code + case 0x49: + // kind: type argument for generic method in method invocation expression + // location: Code + case 0x4A: + // kind: type argument for generic constructor in method reference expression using ::new + // location: Code + case 0x4B: + // kind: type argument for generic method in method reference expression using ::Identifier + // location: Code + + { + // struct: + // type_argument_target { + // u2 offset; + // u1 type_argument_index; + // } + // + if ((byte_i_ref + 3) > type_annotations_typeArray->length()) { + log_debug(redefine, class, annotation)("length() is too small for a type_argument_target"); + return false; + } + + u2 offset = Bytes::get_Java_u2((address) + type_annotations_typeArray->adr_at(byte_i_ref)); + byte_i_ref += 2; + u1 type_argument_index = type_annotations_typeArray->at(byte_i_ref); + byte_i_ref += 1; + + log_debug(redefine, class, annotation) + ("type_argument_target: offset=%d, type_argument_index=%d", offset, type_argument_index); + } break; + + default: + log_debug(redefine, class, annotation)("unknown target_type"); +#ifdef ASSERT + ShouldNotReachHere(); +#endif + return false; + } + + return true; +} // end skip_type_annotation_target() + + +// Read, verify and skip over the type_path part so that rewriting +// can continue in the later parts of the struct. +// +// type_path { +// u1 path_length; +// { +// u1 type_path_kind; +// u1 type_argument_index; +// } path[path_length]; +// } +// +bool VM_RedefineClasses::skip_type_annotation_type_path( + AnnotationArray* type_annotations_typeArray, int &byte_i_ref, TRAPS) { + + if ((byte_i_ref + 1) > type_annotations_typeArray->length()) { + // not enough room for a path_length let alone the rest of the type_path + log_debug(redefine, class, annotation)("length() is too small for a type_path"); + return false; + } + + u1 path_length = type_annotations_typeArray->at(byte_i_ref); + byte_i_ref += 1; + + log_debug(redefine, class, annotation)("type_path: path_length=%d", path_length); + + int calc_path_length = 0; + for (; calc_path_length < path_length; calc_path_length++) { + if ((byte_i_ref + 1 + 1) > type_annotations_typeArray->length()) { + // not enough room for a path + log_debug(redefine, class, annotation) + ("length() is too small for path entry %d of %d", calc_path_length, path_length); + return false; + } + + u1 type_path_kind = type_annotations_typeArray->at(byte_i_ref); + byte_i_ref += 1; + u1 type_argument_index = type_annotations_typeArray->at(byte_i_ref); + byte_i_ref += 1; + + log_debug(redefine, class, annotation) + ("type_path: path[%d]: type_path_kind=%d, type_argument_index=%d", + calc_path_length, type_path_kind, type_argument_index); + + if (type_path_kind > 3 || (type_path_kind != 3 && type_argument_index != 0)) { + // not enough room for a path + log_debug(redefine, class, annotation)("inconsistent type_path values"); + return false; + } + } + assert(path_length == calc_path_length, "sanity check"); + + return true; +} // end skip_type_annotation_type_path() + + +// 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( + const methodHandle& method, TRAPS) { + + if (!method->has_stackmap_table()) { + return; + } + + AnnotationArray* stackmap_data = method->stackmap_data(); + address stackmap_p = (address)stackmap_data->adr_at(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; + + log_debug(redefine, class, stackmap)("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"); + u1 frame_type = *stackmap_p; + stackmap_p++; + + // same_frame { + // u1 frame_type = SAME; /* 0-63 */ + // } + if (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) { + log_debug(redefine, class, stackmap)("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; + + log_debug(redefine, class, stackmap) + ("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: + log_debug(redefine, class, stackmap)("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( + ClassLoaderData* loader_data, + InstanceKlass* scratch_class, constantPoolHandle scratch_cp, + int scratch_cp_length, TRAPS) { + assert(scratch_cp->length() >= scratch_cp_length, "sanity check"); + + // 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. + ConstantPool* cp = ConstantPool::allocate(loader_data, scratch_cp_length, CHECK); + constantPoolHandle smaller_cp(THREAD, cp); + + // preserve version() value in the smaller copy + int version = scratch_cp->version(); + assert(version != 0, "sanity check"); + smaller_cp->set_version(version); + + // attach klass to new constant pool + // reference to the cp holder is needed for copy_operands() + smaller_cp->set_pool_holder(scratch_class); + + scratch_cp->copy_cp_to(1, scratch_cp_length - 1, smaller_cp, 1, THREAD); + if (HAS_PENDING_EXCEPTION) { + // Exception is handled in the caller + loader_data->add_to_deallocate_list(smaller_cp()); + return; + } + scratch_cp = smaller_cp; + + // attach new constant pool to klass + scratch_class->set_constants(scratch_cp()); + scratch_cp->initialize_unresolved_klasses(loader_data, CHECK); + + int i; // for portability + + // update each field in klass to use new constant pool indices as needed + for (JavaFieldStream fs(scratch_class); !fs.done(); fs.next()) { + jshort cur_index = fs.name_index(); + jshort new_index = find_new_index(cur_index); + if (new_index != 0) { + log_trace(redefine, class, constantpool)("field-name_index change: %d to %d", cur_index, new_index); + fs.set_name_index(new_index); + } + cur_index = fs.signature_index(); + new_index = find_new_index(cur_index); + if (new_index != 0) { + log_trace(redefine, class, constantpool)("field-signature_index change: %d to %d", cur_index, new_index); + fs.set_signature_index(new_index); + } + cur_index = fs.initval_index(); + new_index = find_new_index(cur_index); + if (new_index != 0) { + log_trace(redefine, class, constantpool)("field-initval_index change: %d to %d", cur_index, new_index); + fs.set_initval_index(new_index); + } + cur_index = fs.generic_signature_index(); + new_index = find_new_index(cur_index); + if (new_index != 0) { + log_trace(redefine, class, constantpool)("field-generic_signature change: %d to %d", cur_index, new_index); + fs.set_generic_signature_index(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) + InnerClassesIterator iter(scratch_class); + for (; !iter.done(); iter.next()) { + int cur_index = iter.inner_class_info_index(); + 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) { + log_trace(redefine, class, constantpool)("inner_class_info change: %d to %d", cur_index, new_index); + iter.set_inner_class_info_index(new_index); + } + cur_index = iter.outer_class_info_index(); + new_index = find_new_index(cur_index); + if (new_index != 0) { + log_trace(redefine, class, constantpool)("outer_class_info change: %d to %d", cur_index, new_index); + iter.set_outer_class_info_index(new_index); + } + cur_index = iter.inner_name_index(); + new_index = find_new_index(cur_index); + if (new_index != 0) { + log_trace(redefine, class, constantpool)("inner_name change: %d to %d", cur_index, new_index); + iter.set_inner_name_index(new_index); + } + } // end for each inner class + + // Attach each method in klass to the new constant pool and update + // to use new constant pool indices as needed: + Array* methods = scratch_class->methods(); + for (i = methods->length() - 1; i >= 0; i--) { + methodHandle method(THREAD, methods->at(i)); + method->set_constants(scratch_cp()); + + int new_index = find_new_index(method->name_index()); + if (new_index != 0) { + log_trace(redefine, class, constantpool) + ("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) { + log_trace(redefine, class, constantpool) + ("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) { + log_trace(redefine, class, constantpool) + ("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) { + log_trace(redefine, class, constantpool)("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) + + ExceptionTable ex_table(method()); + int ext_length = ex_table.length(); + + for (int j = 0; j < ext_length; j ++) { + int cur_index = ex_table.catch_type_index(j); + int new_index = find_new_index(cur_index); + if (new_index != 0) { + log_trace(redefine, class, constantpool)("ext-klass_index change: %d to %d", cur_index, new_index); + ex_table.set_catch_type_index(j, 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) { + log_trace(redefine, class, constantpool)("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) { + log_trace(redefine, class, constantpool)("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) { + log_trace(redefine, class, constantpool)("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 ClassLoaderDataGraph::classes_do() facility and this helper +// to fix up these pointers. + +// Adjust cpools and vtables closure +void VM_RedefineClasses::AdjustCpoolCacheAndVtable::do_klass(Klass* k) { + + // This is a very busy routine. We don't want too much tracing + // printed out. + bool trace_name_printed = false; + InstanceKlass *the_class = InstanceKlass::cast(_the_class); + + // If the class being redefined is java.lang.Object, we need to fix all + // array class vtables also + if (k->is_array_klass() && _the_class == SystemDictionary::Object_klass()) { + k->vtable().adjust_method_entries(the_class, &trace_name_printed); + + } else if (k->is_instance_klass()) { + HandleMark hm(_thread); + InstanceKlass *ik = InstanceKlass::cast(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 = (_the_class->class_loader() != NULL); + if (is_user_defined && ik->class_loader() == NULL) { + return; + } + + // 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 Method*s for virtual (but not final) methods. + // Default methods, or concrete methods in interfaces are stored + // in the vtable, so if an interface changes we need to check + // adjust_method_entries() for every InstanceKlass, which will also + // adjust the default method vtable indices. + // We also need to adjust any default method entries that are + // not yet in the vtable, because the vtable setup is in progress. + // This must be done after we adjust the default_methods and + // default_vtable_indices for methods already in the vtable. + // If redefining Unsafe, walk all the vtables looking for entries. + if (ik->vtable_length() > 0 && (_the_class->is_interface() + || _the_class == SystemDictionary::internal_Unsafe_klass() + || ik->is_subtype_of(_the_class))) { + // ik->vtable() creates a wrapper object; rm cleans it up + ResourceMark rm(_thread); + + ik->vtable().adjust_method_entries(the_class, &trace_name_printed); + ik->adjust_default_methods(the_class, &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 redefining Unsafe, walk all the itables looking for entries. + if (ik->itable_length() > 0 && (_the_class->is_interface() + || _the_class == SystemDictionary::internal_Unsafe_klass() + || ik->is_subclass_of(_the_class))) { + ResourceMark rm(_thread); + ik->itable().adjust_method_entries(the_class, &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 Method*s 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; + ConstantPoolCache* cp_cache; + + if (ik != _the_class) { + // 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(the_class, &trace_name_printed); + } + } + + // the previous versions' constant pool caches may need adjustment + for (InstanceKlass* pv_node = ik->previous_versions(); + pv_node != NULL; + pv_node = pv_node->previous_versions()) { + cp_cache = pv_node->constants()->cache(); + if (cp_cache != NULL) { + cp_cache->adjust_method_entries(pv_node, &trace_name_printed); + } + } + } +} + +// Clean method data for this class +void VM_RedefineClasses::MethodDataCleaner::do_klass(Klass* k) { + if (k->is_instance_klass()) { + InstanceKlass *ik = InstanceKlass::cast(k); + // Clean MethodData of this class's methods so they don't refer to + // old methods that are no longer running. + Array* methods = ik->methods(); + int num_methods = methods->length(); + for (int index = 0; index < num_methods; ++index) { + if (methods->at(index)->method_data() != NULL) { + methods->at(index)->method_data()->clean_weak_method_links(); + } + } + } +} + +void VM_RedefineClasses::update_jmethod_ids() { + for (int j = 0; j < _matching_methods_length; ++j) { + Method* 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]); + Method::change_method_associated_with_jmethod_id(jmid, new_method_h()); + assert(Method::resolve_jmethod_id(jmid) == _matching_new_methods[j], + "should be replaced"); + } + } +} + +int VM_RedefineClasses::check_methods_and_mark_as_obsolete() { + int emcp_method_count = 0; + int obsolete_count = 0; + int old_index = 0; + for (int j = 0; j < _matching_methods_length; ++j, ++old_index) { + Method* old_method = _matching_old_methods[j]; + Method* new_method = _matching_new_methods[j]; + Method* old_array_method; + + // Maintain an old_index into the _old_methods array by skipping + // deleted methods + while ((old_array_method = _old_methods->at(old_index)) != old_method) { + ++old_index; + } + + if (MethodComparator::methods_EMCP(old_method, new_method)) { + // The EMCP definition from JSR-163 requires the bytecodes to be + // the same with the exception of constant pool indices which may + // differ. However, the constants referred to by those indices + // must be the same. + // + // We use methods_EMCP() for comparison since constant pool + // merging can remove duplicate constant pool entries that were + // present in the old method and removed from the rewritten new + // method. A faster binary comparison function would consider the + // old and new methods to be different when they are actually + // EMCP. + // + // 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 ConstMethod* and this presents another + // possible avenue to space savings. The ConstMethod* in the + // new method contains possibly new attributes (LNT, LVT, etc). + // At first glance, it seems possible to save space by replacing + // the ConstMethod* in the old method with the ConstMethod* + // from the new method. The old and new methods would share the + // same ConstMethod* and we would save the space occupied by + // the old ConstMethod*. However, the ConstMethod* contains + // a back reference to the containing method. Sharing the + // ConstMethod* 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 ConstMethod* from the new + // method to the old method and then overwrite the new method with + // the old method. Since the ConstMethod* 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 + // ConstMethod* from the old bcp in the old ConstMethod*. 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. + + // Count number of methods that are EMCP. The method will be marked + // old but not obsolete if it is EMCP. + emcp_method_count++; + + // 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 so they become new entries in + // the jmethodID cache in InstanceKlass + assert(old_method->method_idnum() == new_method->method_idnum(), "must match"); + u2 num = InstanceKlass::cast(_the_class)->next_method_idnum(); + if (num != ConstMethod::UNSET_IDNUM) { + old_method->set_method_idnum(num); + } + + // With tracing we try not to "yack" too much. The position of + // this trace assumes there are fewer obsolete methods than + // EMCP methods. + if (log_is_enabled(Trace, redefine, class, obsolete, mark)) { + ResourceMark rm; + log_trace(redefine, class, obsolete, mark) + ("mark %s(%s) as obsolete", old_method->name()->as_C_string(), old_method->signature()->as_C_string()); + } + } + old_method->set_is_old(); + } + for (int i = 0; i < _deleted_methods_length; ++i) { + Method* old_method = _deleted_methods[i]; + + assert(!old_method->has_vtable_index(), + "cannot delete methods with vtable entries");; + + // Mark all deleted methods as old, obsolete and deleted + old_method->set_is_deleted(); + 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. + if (log_is_enabled(Trace, redefine, class, obsolete, mark)) { + ResourceMark rm; + log_trace(redefine, class, obsolete, mark) + ("mark deleted %s(%s) as obsolete", old_method->name()->as_C_string(), old_method->signature()->as_C_string()); + } + } + assert((emcp_method_count + obsolete_count) == _old_methods->length(), + "sanity check"); + log_trace(redefine, class, obsolete, mark)("EMCP_cnt=%d, obsolete_cnt=%d", emcp_method_count, obsolete_count); + return emcp_method_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: + InstanceKlass* the_class; + int prefix_count; + char** prefixes; + + // Recursively search the binary tree of possibly prefixed method names. + // Iteration could be used if all agents were well behaved. Full tree walk is + // more resilent to agents not cleaning up intermediate methods. + // Branch at each depth in the binary tree is: + // (1) without the prefix. + // (2) with the prefix. + // where 'prefix' is the prefix at that 'depth' (first prefix, second prefix,...) + Method* search_prefix_name_space(int depth, char* name_str, size_t name_len, + Symbol* signature) { + TempNewSymbol name_symbol = SymbolTable::probe(name_str, (int)name_len); + if (name_symbol != NULL) { + Method* method = 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(Method* method) { + Symbol* name = method->name(); + char* name_str = name->as_utf8(); + + // Old prefixing may be defunct, strip prefixes, if any. + for (int i = prefix_count-1; i >= 0; i--) { + char* prefix = prefixes[i]; + size_t prefix_len = strlen(prefix); + if (strncmp(prefix, name_str, prefix_len) == 0) { + name_str += prefix_len; + } + } + return name_str; + } + + // Strip any prefixes off the old native method, then try to find a + // (possibly prefixed) new native that matches it. + Method* strip_and_search_for_new_native(Method* method) { + ResourceMark rm; + char* name_str = method_name_without_prefixes(method); + return search_prefix_name_space(0, name_str, strlen(name_str), + method->signature()); + } + + public: + + // Construct a native method transfer processor for this class. + TransferNativeFunctionRegistration(InstanceKlass* _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(Method** old_methods, int methods_length) { + for (int j = 0; j < methods_length; j++) { + Method* old_method = old_methods[j]; + + if (old_method->is_native() && old_method->has_native_function()) { + Method* new_method = strip_and_search_for_new_native(old_method); + if (new_method != NULL) { + // Actually set the native function in the new method. + // Redefine does not send events (except CFLH), certainly not this + // behind the scenes re-registration. + new_method->set_native_function(old_method->native_function(), + !Method::native_bind_event_is_interesting); + } + } + } + } +}; + +// Don't lose the association between a native method and its JNI function. +void VM_RedefineClasses::transfer_old_native_function_registrations(InstanceKlass* 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(InstanceKlass* ik, 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()) { + CodeCache::flush_evol_dependents_on(ik); + } 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 + 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() { + Method* old_method; + Method* new_method; + + _matching_old_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length()); + _matching_new_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length()); + _added_methods = NEW_RESOURCE_ARRAY(Method*, _new_methods->length()); + _deleted_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length()); + + _matching_methods_length = 0; + _deleted_methods_length = 0; + _added_methods_length = 0; + + int nj = 0; + int oj = 0; + while (true) { + if (oj >= _old_methods->length()) { + if (nj >= _new_methods->length()) { + break; // we've looked at everything, done + } + // New method at the end + new_method = _new_methods->at(nj); + _added_methods[_added_methods_length++] = new_method; + ++nj; + } else if (nj >= _new_methods->length()) { + // Old method, at the end, is deleted + old_method = _old_methods->at(oj); + _deleted_methods[_deleted_methods_length++] = old_method; + ++oj; + } else { + old_method = _old_methods->at(oj); + new_method = _new_methods->at(nj); + if (old_method->name() == new_method->name()) { + if (old_method->signature() == new_method->signature()) { + _matching_old_methods[_matching_methods_length ] = 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"); +} + + +void VM_RedefineClasses::swap_annotations(InstanceKlass* the_class, + InstanceKlass* scratch_class) { + // Swap annotation fields values + Annotations* old_annotations = the_class->annotations(); + the_class->set_annotations(scratch_class->annotations()); + scratch_class->set_annotations(old_annotations); +} + + +// 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 +// ClassLoaderDataGraph::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, + InstanceKlass* scratch_class, TRAPS) { + + HandleMark hm(THREAD); // make sure handles from this call are freed + + if (log_is_enabled(Info, redefine, class, timer)) { + _timer_rsc_phase1.start(); + } + + InstanceKlass* the_class = get_ik(the_jclass); + + // Remove all breakpoints in methods of this class + JvmtiBreakpoints& jvmti_breakpoints = JvmtiCurrentBreakpoints::get_jvmti_breakpoints(); + jvmti_breakpoints.clearall_in_class_at_safepoint(the_class); + + // 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 = the_class; + compute_added_deleted_matching_methods(); + update_jmethod_ids(); + + _any_class_has_resolved_methods = the_class->has_resolved_methods() || _any_class_has_resolved_methods; + + // 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--) { + Method* method = _old_methods->at(i); + method->set_constants(scratch_class->constants()); + } + + // NOTE: this doesn't work because you can redefine the same class in two + // threads, each getting their own constant pool data appended to the + // original constant pool. In order for the new methods to work when they + // become old methods, they need to keep their updated copy of the constant pool. + + { + // walk all previous versions of the klass + InstanceKlass *ik = the_class; + PreviousVersionWalker pvw(ik); + do { + ik = pvw.next_previous_version(); + if (ik != NULL) { + + // 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 + Array* prev_methods = ik->methods(); + for (int i = prev_methods->length() - 1; i >= 0; i--) { + Method* method = prev_methods->at(i); + method->set_constants(scratch_class->constants()); + } + } + } while (ik != 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. + + Array* old_ordering = the_class->method_ordering(); + the_class->set_method_ordering(scratch_class->method_ordering()); + scratch_class->set_method_ordering(old_ordering); + + ConstantPool* 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 number of methods that are EMCP for add_previous_version() call below + int emcp_method_count = check_methods_and_mark_as_obsolete(); + 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. + if (the_class->get_cached_class_file_bytes() == 0) { + // the_class doesn't have a cache yet so copy it + the_class->set_cached_class_file(scratch_class->get_cached_class_file()); + } + else if (scratch_class->get_cached_class_file_bytes() != + the_class->get_cached_class_file_bytes()) { + // The same class can be present twice in the scratch classes list or there + // are multiple concurrent RetransformClasses calls on different threads. + // In such cases we have to deallocate scratch_class cached_class_file. + os::free(scratch_class->get_cached_class_file()); + } + + // NULL out in scratch class to not delete twice. The class to be redefined + // always owns these bytes. + scratch_class->set_cached_class_file(NULL); + + // Replace inner_classes + Array* 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_index( + scratch_class->source_file_name_index()); + + // Copy the "source debug extension" attribute from new class version + the_class->set_source_debug_extension( + scratch_class->source_debug_extension(), + scratch_class->source_debug_extension() == NULL ? 0 : + (int)strlen(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); + } + + swap_annotations(the_class, scratch_class); + + // 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); + + // Replace fingerprint data + the_class->set_has_passed_fingerprint_check(scratch_class->has_passed_fingerprint_check()); + the_class->store_fingerprint(scratch_class->get_stored_fingerprint()); + + the_class->set_has_been_redefined(); + + if (!the_class->should_be_initialized()) { + // Class was already initialized, so AOT has only seen the original version. + // We need to let AOT look at it again. + AOTLoader::load_for_klass(the_class, THREAD); + } + + // keep track of previous versions of this class + the_class->add_previous_version(scratch_class, emcp_method_count); + + _timer_rsc_phase1.stop(); + if (log_is_enabled(Info, redefine, class, timer)) { + _timer_rsc_phase2.start(); + } + + // Adjust constantpool caches and vtables for all classes + // that reference methods of the evolved class. + AdjustCpoolCacheAndVtable adjust_cpool_cache_and_vtable(THREAD); + ClassLoaderDataGraph::classes_do(&adjust_cpool_cache_and_vtable); + + 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_class_counter((InstanceKlass *)the_class, THREAD); + { + ResourceMark rm(THREAD); + // increment the classRedefinedCount field in the_class and in any + // direct and indirect subclasses of the_class + log_info(redefine, class, load) + ("redefined name=%s, count=%d (avail_mem=" UINT64_FORMAT "K)", + the_class->external_name(), java_lang_Class::classRedefinedCount(the_class->java_mirror()), os::available_memory() >> 10); + Events::log_redefinition(THREAD, "redefined class name=%s, count=%d", + the_class->external_name(), + java_lang_Class::classRedefinedCount(the_class->java_mirror())); + + } + _timer_rsc_phase2.stop(); +} // 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(); + Klass* class_oop = java_lang_Class::as_Klass(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) { + // _the_class count is printed at end of redefine_single_class() + log_debug(redefine, class, subclass)("updated count in subclass=%s to %d", ik->external_name(), new_count); + } + + for (Klass *subk = ik->subklass(); subk != NULL; + subk = subk->next_sibling()) { + if (subk->is_instance_klass()) { + // Only update instanceKlasses + InstanceKlass *subik = InstanceKlass::cast(subk); + // recursively do subclasses of the current subclass + increment_class_counter(subik, THREAD); + } + } +} + +void VM_RedefineClasses::CheckClass::do_klass(Klass* k) { + bool no_old_methods = true; // be optimistic + + // Both array and instance classes have vtables. + // a vtable should never contain old or obsolete methods + ResourceMark rm(_thread); + if (k->vtable_length() > 0 && + !k->vtable().check_no_old_or_obsolete_entries()) { + if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) { + log_trace(redefine, class, obsolete, metadata) + ("klassVtable::check_no_old_or_obsolete_entries failure -- OLD or OBSOLETE method found -- class: %s", + k->signature_name()); + k->vtable().dump_vtable(); + } + no_old_methods = false; + } + + if (k->is_instance_klass()) { + HandleMark hm(_thread); + InstanceKlass *ik = InstanceKlass::cast(k); + + // an itable should never contain old or obsolete methods + if (ik->itable_length() > 0 && + !ik->itable().check_no_old_or_obsolete_entries()) { + if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) { + log_trace(redefine, class, obsolete, metadata) + ("klassItable::check_no_old_or_obsolete_entries failure -- OLD or OBSOLETE method found -- class: %s", + ik->signature_name()); + ik->itable().dump_itable(); + } + no_old_methods = false; + } + + // the constant pool cache should never contain non-deleted old or obsolete methods + if (ik->constants() != NULL && + ik->constants()->cache() != NULL && + !ik->constants()->cache()->check_no_old_or_obsolete_entries()) { + if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) { + log_trace(redefine, class, obsolete, metadata) + ("cp-cache::check_no_old_or_obsolete_entries failure -- OLD or OBSOLETE method found -- class: %s", + ik->signature_name()); + ik->constants()->cache()->dump_cache(); + } + no_old_methods = false; + } + } + + // print and fail guarantee if old methods are found. + if (!no_old_methods) { + if (log_is_enabled(Trace, redefine, class, obsolete, metadata)) { + dump_methods(); + } else { + log_trace(redefine, class)("Use the '-Xlog:redefine+class*:' option " + "to see more info about the following guarantee() failure."); + } + guarantee(false, "OLD and/or OBSOLETE method(s) found"); + } +} + + +void VM_RedefineClasses::dump_methods() { + int j; + log_trace(redefine, class, dump)("_old_methods --"); + for (j = 0; j < _old_methods->length(); ++j) { + LogStreamHandle(Trace, redefine, class, dump) log_stream; + Method* m = _old_methods->at(j); + log_stream.print("%4d (%5d) ", j, m->vtable_index()); + m->access_flags().print_on(&log_stream); + log_stream.print(" -- "); + m->print_name(&log_stream); + log_stream.cr(); + } + log_trace(redefine, class, dump)("_new_methods --"); + for (j = 0; j < _new_methods->length(); ++j) { + LogStreamHandle(Trace, redefine, class, dump) log_stream; + Method* m = _new_methods->at(j); + log_stream.print("%4d (%5d) ", j, m->vtable_index()); + m->access_flags().print_on(&log_stream); + log_stream.print(" -- "); + m->print_name(&log_stream); + log_stream.cr(); + } + log_trace(redefine, class, dump)("_matching_methods --"); + for (j = 0; j < _matching_methods_length; ++j) { + LogStreamHandle(Trace, redefine, class, dump) log_stream; + Method* m = _matching_old_methods[j]; + log_stream.print("%4d (%5d) ", j, m->vtable_index()); + m->access_flags().print_on(&log_stream); + log_stream.print(" -- "); + m->print_name(); + log_stream.cr(); + + m = _matching_new_methods[j]; + log_stream.print(" (%5d) ", m->vtable_index()); + m->access_flags().print_on(&log_stream); + log_stream.cr(); + } + log_trace(redefine, class, dump)("_deleted_methods --"); + for (j = 0; j < _deleted_methods_length; ++j) { + LogStreamHandle(Trace, redefine, class, dump) log_stream; + Method* m = _deleted_methods[j]; + log_stream.print("%4d (%5d) ", j, m->vtable_index()); + m->access_flags().print_on(&log_stream); + log_stream.print(" -- "); + m->print_name(&log_stream); + log_stream.cr(); + } + log_trace(redefine, class, dump)("_added_methods --"); + for (j = 0; j < _added_methods_length; ++j) { + LogStreamHandle(Trace, redefine, class, dump) log_stream; + Method* m = _added_methods[j]; + log_stream.print("%4d (%5d) ", j, m->vtable_index()); + m->access_flags().print_on(&log_stream); + log_stream.print(" -- "); + m->print_name(&log_stream); + log_stream.cr(); + } +} + +void VM_RedefineClasses::print_on_error(outputStream* st) const { + VM_Operation::print_on_error(st); + if (_the_class != NULL) { + ResourceMark rm; + st->print_cr(", redefining class %s", _the_class->external_name()); + } +}