truffle: src/share/vm/prims/jvmtiRedefineClasses.cpp comparison

comparison src/share/vm/prims/jvmtiRedefineClasses.cpp @ 0:a61af66fc99e jdk7-b24

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author	duke
date	Sat, 01 Dec 2007 00:00:00 +0000
parents
children	0af8b0718fc9 ea20d7ce26b0

comparison

equal deleted inserted replaced

--1:000000000000
+:a61af66fc99e
+/*
+* Copyright 2003-2007 Sun Microsystems, Inc.  All Rights Reserved.
+* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+*
+* This code is free software; you can redistribute it and/or modify it
+* under the terms of the GNU General Public License version 2 only, as
+* published by the Free Software Foundation.
+*
+* This code is distributed in the hope that it will be useful, but WITHOUT
+* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+* FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+* version 2 for more details (a copy is included in the LICENSE file that
+* accompanied this code).
+*
+* You should have received a copy of the GNU General Public License version
+* 2 along with this work; if not, write to the Free Software Foundation,
+* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+*
+* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+* CA 95054 USA or visit www.sun.com if you need additional information or
+* have any questions.
+*
+*/
+# include "incls/_precompiled.incl"
+# include "incls/_jvmtiRedefineClasses.cpp.incl"
+objArrayOop VM_RedefineClasses::_old_methods = NULL;
+objArrayOop VM_RedefineClasses::_new_methods = NULL;
+methodOop*  VM_RedefineClasses::_matching_old_methods = NULL;
+methodOop*  VM_RedefineClasses::_matching_new_methods = NULL;
+methodOop*  VM_RedefineClasses::_deleted_methods      = NULL;
+methodOop*  VM_RedefineClasses::_added_methods        = NULL;
+int         VM_RedefineClasses::_matching_methods_length = 0;
+int         VM_RedefineClasses::_deleted_methods_length  = 0;
+int         VM_RedefineClasses::_added_methods_length    = 0;
+klassOop    VM_RedefineClasses::_the_class_oop = NULL;
+VM_RedefineClasses::VM_RedefineClasses(jint class_count,
+const jvmtiClassDefinition *class_defs,
+JvmtiClassLoadKind class_load_kind) {
+_class_count = class_count;
+_class_defs = class_defs;
+_class_load_kind = class_load_kind;
+_res = JVMTI_ERROR_NONE;
+}
+bool VM_RedefineClasses::doit_prologue() {
+if (_class_count == 0) {
+_res = JVMTI_ERROR_NONE;
+return false;
+}
+if (_class_defs == NULL) {
+_res = JVMTI_ERROR_NULL_POINTER;
+return false;
+}
+for (int i = 0; i < _class_count; i++) {
+if (_class_defs[i].klass == NULL) {
+_res = JVMTI_ERROR_INVALID_CLASS;
+return false;
+}
+if (_class_defs[i].class_byte_count == 0) {
+_res = JVMTI_ERROR_INVALID_CLASS_FORMAT;
+return false;
+}
+if (_class_defs[i].class_bytes == NULL) {
+_res = JVMTI_ERROR_NULL_POINTER;
+return false;
+}
+}
+// Start timer after all the sanity checks; not quite accurate, but
+// better than adding a bunch of stop() calls.
+RC_TIMER_START(_timer_vm_op_prologue);
+// We first load new class versions in the prologue, because somewhere down the
+// call chain it is required that the current thread is a Java thread.
+_res = load_new_class_versions(Thread::current());
+if (_res != JVMTI_ERROR_NONE) {
+// Free os::malloc allocated memory in load_new_class_version.
+os::free(_scratch_classes);
+RC_TIMER_STOP(_timer_vm_op_prologue);
+return false;
+}
+RC_TIMER_STOP(_timer_vm_op_prologue);
+return true;
+}
+void VM_RedefineClasses::doit() {
+Thread *thread = Thread::current();
+if (UseSharedSpaces) {
+// Sharing is enabled so we remap the shared readonly space to
+// shared readwrite, private just in case we need to redefine
+// a shared class. We do the remap during the doit() phase of
+// the safepoint to be safer.
+if (!CompactingPermGenGen::remap_shared_readonly_as_readwrite()) {
+RC_TRACE_WITH_THREAD(0x00000001, thread,
+("failed to remap shared readonly space to readwrite, private"));
+_res = JVMTI_ERROR_INTERNAL;
+return;
+}
+}
+for (int i = 0; i < _class_count; i++) {
+redefine_single_class(_class_defs[i].klass, _scratch_classes[i], thread);
+}
+// Disable any dependent concurrent compilations
+SystemDictionary::notice_modification();
+// Set flag indicating that some invariants are no longer true.
+// See jvmtiExport.hpp for detailed explanation.
+JvmtiExport::set_has_redefined_a_class();
+#ifdef ASSERT
+SystemDictionary::classes_do(check_class, thread);
+#endif
+}
+void VM_RedefineClasses::doit_epilogue() {
+// Free os::malloc allocated memory.
+// The memory allocated in redefine will be free'ed in next VM operation.
+os::free(_scratch_classes);
+if (RC_TRACE_ENABLED(0x00000004)) {
+// Used to have separate timers for "doit" and "all", but the timer
+// overhead skewed the measurements.
+jlong doit_time = _timer_rsc_phase1.milliseconds() +
+_timer_rsc_phase2.milliseconds();
+jlong all_time = _timer_vm_op_prologue.milliseconds() + doit_time;
+RC_TRACE(0x00000004, ("vm_op: all=" UINT64_FORMAT
+"  prologue=" UINT64_FORMAT "  doit=" UINT64_FORMAT, all_time,
+_timer_vm_op_prologue.milliseconds(), doit_time));
+RC_TRACE(0x00000004,
+("redefine_single_class: phase1=" UINT64_FORMAT "  phase2=" UINT64_FORMAT,
+_timer_rsc_phase1.milliseconds(), _timer_rsc_phase2.milliseconds()));
+}
+}
+bool VM_RedefineClasses::is_modifiable_class(oop klass_mirror) {
+// classes for primitives cannot be redefined
+if (java_lang_Class::is_primitive(klass_mirror)) {
+return false;
+}
+klassOop the_class_oop = java_lang_Class::as_klassOop(klass_mirror);
+// classes for arrays cannot be redefined
+if (the_class_oop == NULL || !Klass::cast(the_class_oop)->oop_is_instance()) {
+return false;
+}
+return true;
+}
+// Append the current entry at scratch_i in scratch_cp to *merge_cp_p
+// where the end of *merge_cp_p is specified by *merge_cp_length_p. For
+// direct CP entries, there is just the current entry to append. For
+// indirect and double-indirect CP entries, there are zero or more
+// referenced CP entries along with the current entry to append.
+// Indirect and double-indirect CP entries are handled by recursive
+// calls to append_entry() as needed. The referenced CP entries are
+// always appended to *merge_cp_p before the referee CP entry. These
+// referenced CP entries may already exist in *merge_cp_p in which case
+// there is nothing extra to append and only the current entry is
+// appended.
+void VM_RedefineClasses::append_entry(constantPoolHandle scratch_cp,
+int scratch_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p,
+TRAPS) {
+// append is different depending on entry tag type
+switch (scratch_cp->tag_at(scratch_i).value()) {
+// The old verifier is implemented outside the VM. It loads classes,
+// but does not resolve constant pool entries directly so we never
+// see Class entries here with the old verifier. Similarly the old
+// verifier does not like Class entries in the input constant pool.
+// The split-verifier is implemented in the VM so it can optionally
+// and directly resolve constant pool entries to load classes. The
+// split-verifier can accept either Class entries or UnresolvedClass
+// entries in the input constant pool. We revert the appended copy
+// back to UnresolvedClass so that either verifier will be happy
+// with the constant pool entry.
+case JVM_CONSTANT_Class:
+{
+// revert the copy to JVM_CONSTANT_UnresolvedClass
+(*merge_cp_p)->unresolved_klass_at_put(*merge_cp_length_p,
+scratch_cp->klass_name_at(scratch_i));
+if (scratch_i != *merge_cp_length_p) {
+// The new entry in *merge_cp_p is at a different index than
+// the new entry in scratch_cp so we need to map the index values.
+map_index(scratch_cp, scratch_i, *merge_cp_length_p);
+}
+(*merge_cp_length_p)++;
+} break;
+// these are direct CP entries so they can be directly appended,
+// but double and long take two constant pool entries
+case JVM_CONSTANT_Double:  // fall through
+case JVM_CONSTANT_Long:
+{
+scratch_cp->copy_entry_to(scratch_i, *merge_cp_p, *merge_cp_length_p,
+THREAD);
+if (scratch_i != *merge_cp_length_p) {
+// The new entry in *merge_cp_p is at a different index than
+// the new entry in scratch_cp so we need to map the index values.
+map_index(scratch_cp, scratch_i, *merge_cp_length_p);
+}
+(*merge_cp_length_p) += 2;
+} break;
+// these are direct CP entries so they can be directly appended
+case JVM_CONSTANT_Float:   // fall through
+case JVM_CONSTANT_Integer: // fall through
+case JVM_CONSTANT_Utf8:    // fall through
+// This was an indirect CP entry, but it has been changed into
+// an interned string so this entry can be directly appended.
+case JVM_CONSTANT_String:      // fall through
+// These were indirect CP entries, but they have been changed into
+// symbolOops so these entries can be directly appended.
+case JVM_CONSTANT_UnresolvedClass:  // fall through
+case JVM_CONSTANT_UnresolvedString:
+{
+scratch_cp->copy_entry_to(scratch_i, *merge_cp_p, *merge_cp_length_p,
+THREAD);
+if (scratch_i != *merge_cp_length_p) {
+// The new entry in *merge_cp_p is at a different index than
+// the new entry in scratch_cp so we need to map the index values.
+map_index(scratch_cp, scratch_i, *merge_cp_length_p);
+}
+(*merge_cp_length_p)++;
+} break;
+// this is an indirect CP entry so it needs special handling
+case JVM_CONSTANT_NameAndType:
+{
+int name_ref_i = scratch_cp->name_ref_index_at(scratch_i);
+int new_name_ref_i = 0;
+bool match = (name_ref_i < *merge_cp_length_p) &&
+scratch_cp->compare_entry_to(name_ref_i, *merge_cp_p, name_ref_i,
+THREAD);
+if (!match) {
+// forward reference in *merge_cp_p or not a direct match
+int found_i = scratch_cp->find_matching_entry(name_ref_i, *merge_cp_p,
+THREAD);
+if (found_i != 0) {
+guarantee(found_i != name_ref_i,
+"compare_entry_to() and find_matching_entry() do not agree");
+// Found a matching entry somewhere else in *merge_cp_p so
+// just need a mapping entry.
+new_name_ref_i = found_i;
+map_index(scratch_cp, name_ref_i, found_i);
+} else {
+// no match found so we have to append this entry to *merge_cp_p
+append_entry(scratch_cp, name_ref_i, merge_cp_p, merge_cp_length_p,
+THREAD);
+// The above call to append_entry() can only append one entry
+// so the post call query of *merge_cp_length_p is only for
+// the sake of consistency.
+new_name_ref_i = *merge_cp_length_p - 1;
+}
+}
+int signature_ref_i = scratch_cp->signature_ref_index_at(scratch_i);
+int new_signature_ref_i = 0;
+match = (signature_ref_i < *merge_cp_length_p) &&
+scratch_cp->compare_entry_to(signature_ref_i, *merge_cp_p,
+signature_ref_i, THREAD);
+if (!match) {
+// forward reference in *merge_cp_p or not a direct match
+int found_i = scratch_cp->find_matching_entry(signature_ref_i,
+*merge_cp_p, THREAD);
+if (found_i != 0) {
+guarantee(found_i != signature_ref_i,
+"compare_entry_to() and find_matching_entry() do not agree");
+// Found a matching entry somewhere else in *merge_cp_p so
+// just need a mapping entry.
+new_signature_ref_i = found_i;
+map_index(scratch_cp, signature_ref_i, found_i);
+} else {
+// no match found so we have to append this entry to *merge_cp_p
+append_entry(scratch_cp, signature_ref_i, merge_cp_p,
+merge_cp_length_p, THREAD);
+// The above call to append_entry() can only append one entry
+// so the post call query of *merge_cp_length_p is only for
+// the sake of consistency.
+new_signature_ref_i = *merge_cp_length_p - 1;
+}
+}
+// If the referenced entries already exist in *merge_cp_p, then
+// both new_name_ref_i and new_signature_ref_i will both be 0.
+// In that case, all we are appending is the current entry.
+if (new_name_ref_i == 0) {
+new_name_ref_i = name_ref_i;
+} else {
+RC_TRACE(0x00080000,
+("NameAndType entry@%d name_ref_index change: %d to %d",
+*merge_cp_length_p, name_ref_i, new_name_ref_i));
+}
+if (new_signature_ref_i == 0) {
+new_signature_ref_i = signature_ref_i;
+} else {
+RC_TRACE(0x00080000,
+("NameAndType entry@%d signature_ref_index change: %d to %d",
+*merge_cp_length_p, signature_ref_i, new_signature_ref_i));
+}
+(*merge_cp_p)->name_and_type_at_put(*merge_cp_length_p,
+new_name_ref_i, new_signature_ref_i);
+if (scratch_i != *merge_cp_length_p) {
+// The new entry in *merge_cp_p is at a different index than
+// the new entry in scratch_cp so we need to map the index values.
+map_index(scratch_cp, scratch_i, *merge_cp_length_p);
+}
+(*merge_cp_length_p)++;
+} break;
+// this is a double-indirect CP entry so it needs special handling
+case JVM_CONSTANT_Fieldref:           // fall through
+case JVM_CONSTANT_InterfaceMethodref: // fall through
+case JVM_CONSTANT_Methodref:
+{
+int klass_ref_i = scratch_cp->uncached_klass_ref_index_at(scratch_i);
+int new_klass_ref_i = 0;
+bool match = (klass_ref_i < *merge_cp_length_p) &&
+scratch_cp->compare_entry_to(klass_ref_i, *merge_cp_p, klass_ref_i,
+THREAD);
+if (!match) {
+// forward reference in *merge_cp_p or not a direct match
+int found_i = scratch_cp->find_matching_entry(klass_ref_i, *merge_cp_p,
+THREAD);
+if (found_i != 0) {
+guarantee(found_i != klass_ref_i,
+"compare_entry_to() and find_matching_entry() do not agree");
+// Found a matching entry somewhere else in *merge_cp_p so
+// just need a mapping entry.
+new_klass_ref_i = found_i;
+map_index(scratch_cp, klass_ref_i, found_i);
+} else {
+// no match found so we have to append this entry to *merge_cp_p
+append_entry(scratch_cp, klass_ref_i, merge_cp_p, merge_cp_length_p,
+THREAD);
+// The above call to append_entry() can only append one entry
+// so the post call query of *merge_cp_length_p is only for
+// the sake of consistency. Without the optimization where we
+// use JVM_CONSTANT_UnresolvedClass, then up to two entries
+// could be appended.
+new_klass_ref_i = *merge_cp_length_p - 1;
+}
+}
+int name_and_type_ref_i =
+scratch_cp->uncached_name_and_type_ref_index_at(scratch_i);
+int new_name_and_type_ref_i = 0;
+match = (name_and_type_ref_i < *merge_cp_length_p) &&
+scratch_cp->compare_entry_to(name_and_type_ref_i, *merge_cp_p,
+name_and_type_ref_i, THREAD);
+if (!match) {
+// forward reference in *merge_cp_p or not a direct match
+int found_i = scratch_cp->find_matching_entry(name_and_type_ref_i,
+*merge_cp_p, THREAD);
+if (found_i != 0) {
+guarantee(found_i != name_and_type_ref_i,
+"compare_entry_to() and find_matching_entry() do not agree");
+// Found a matching entry somewhere else in *merge_cp_p so
+// just need a mapping entry.
+new_name_and_type_ref_i = found_i;
+map_index(scratch_cp, name_and_type_ref_i, found_i);
+} else {
+// no match found so we have to append this entry to *merge_cp_p
+append_entry(scratch_cp, name_and_type_ref_i, merge_cp_p,
+merge_cp_length_p, THREAD);
+// The above call to append_entry() can append more than
+// one entry so the post call query of *merge_cp_length_p
+// is required in order to get the right index for the
+// JVM_CONSTANT_NameAndType entry.
+new_name_and_type_ref_i = *merge_cp_length_p - 1;
+}
+}
+// If the referenced entries already exist in *merge_cp_p, then
+// both new_klass_ref_i and new_name_and_type_ref_i will both be
+// 0. In that case, all we are appending is the current entry.
+if (new_klass_ref_i == 0) {
+new_klass_ref_i = klass_ref_i;
+}
+if (new_name_and_type_ref_i == 0) {
+new_name_and_type_ref_i = name_and_type_ref_i;
+}
+const char *entry_name;
+switch (scratch_cp->tag_at(scratch_i).value()) {
+case JVM_CONSTANT_Fieldref:
+entry_name = "Fieldref";
+(*merge_cp_p)->field_at_put(*merge_cp_length_p, new_klass_ref_i,
+new_name_and_type_ref_i);
+break;
+case JVM_CONSTANT_InterfaceMethodref:
+entry_name = "IFMethodref";
+(*merge_cp_p)->interface_method_at_put(*merge_cp_length_p,
+new_klass_ref_i, new_name_and_type_ref_i);
+break;
+case JVM_CONSTANT_Methodref:
+entry_name = "Methodref";
+(*merge_cp_p)->method_at_put(*merge_cp_length_p, new_klass_ref_i,
+new_name_and_type_ref_i);
+break;
+default:
+guarantee(false, "bad switch");
+break;
+}
+if (klass_ref_i != new_klass_ref_i) {
+RC_TRACE(0x00080000, ("%s entry@%d class_index changed: %d to %d",
+entry_name, *merge_cp_length_p, klass_ref_i, new_klass_ref_i));
+}
+if (name_and_type_ref_i != new_name_and_type_ref_i) {
+RC_TRACE(0x00080000,
+("%s entry@%d name_and_type_index changed: %d to %d",
+entry_name, *merge_cp_length_p, name_and_type_ref_i,
+new_name_and_type_ref_i));
+}
+if (scratch_i != *merge_cp_length_p) {
+// The new entry in *merge_cp_p is at a different index than
+// the new entry in scratch_cp so we need to map the index values.
+map_index(scratch_cp, scratch_i, *merge_cp_length_p);
+}
+(*merge_cp_length_p)++;
+} break;
+// At this stage, Class or UnresolvedClass could be here, but not
+// ClassIndex
+case JVM_CONSTANT_ClassIndex: // fall through
+// Invalid is used as the tag for the second constant pool entry
+// occupied by JVM_CONSTANT_Double or JVM_CONSTANT_Long. It should
+// not be seen by itself.
+case JVM_CONSTANT_Invalid: // fall through
+// At this stage, String or UnresolvedString could be here, but not
+// StringIndex
+case JVM_CONSTANT_StringIndex: // fall through
+// At this stage JVM_CONSTANT_UnresolvedClassInError should not be
+// here
+case JVM_CONSTANT_UnresolvedClassInError: // fall through
+default:
+{
+// leave a breadcrumb
+jbyte bad_value = scratch_cp->tag_at(scratch_i).value();
+ShouldNotReachHere();
+} break;
+} // end switch tag value
+} // end append_entry()
+void VM_RedefineClasses::swap_all_method_annotations(int i, int j, instanceKlassHandle scratch_class) {
+typeArrayOop save;
+save = scratch_class->get_method_annotations_of(i);
+scratch_class->set_method_annotations_of(i, scratch_class->get_method_annotations_of(j));
+scratch_class->set_method_annotations_of(j, save);
+save = scratch_class->get_method_parameter_annotations_of(i);
+scratch_class->set_method_parameter_annotations_of(i, scratch_class->get_method_parameter_annotations_of(j));
+scratch_class->set_method_parameter_annotations_of(j, save);
+save = scratch_class->get_method_default_annotations_of(i);
+scratch_class->set_method_default_annotations_of(i, scratch_class->get_method_default_annotations_of(j));
+scratch_class->set_method_default_annotations_of(j, save);
+}
+jvmtiError VM_RedefineClasses::compare_and_normalize_class_versions(
+instanceKlassHandle the_class,
+instanceKlassHandle scratch_class) {
+int i;
+// Check superclasses, or rather their names, since superclasses themselves can be
+// requested to replace.
+// Check for NULL superclass first since this might be java.lang.Object
+if (the_class->super() != scratch_class->super() &&
+(the_class->super() == NULL || scratch_class->super() == NULL ||
+Klass::cast(the_class->super())->name() !=
+Klass::cast(scratch_class->super())->name())) {
+return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
+}
+// Check if the number, names and order of directly implemented interfaces are the same.
+// I think in principle we should just check if the sets of names of directly implemented
+// interfaces are the same, i.e. the order of declaration (which, however, if changed in the
+// .java file, also changes in .class file) should not matter. However, comparing sets is
+// technically a bit more difficult, and, more importantly, I am not sure at present that the
+// order of interfaces does not matter on the implementation level, i.e. that the VM does not
+// rely on it somewhere.
+objArrayOop k_interfaces = the_class->local_interfaces();
+objArrayOop k_new_interfaces = scratch_class->local_interfaces();
+int n_intfs = k_interfaces->length();
+if (n_intfs != k_new_interfaces->length()) {
+return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
+}
+for (i = 0; i < n_intfs; i++) {
+if (Klass::cast((klassOop) k_interfaces->obj_at(i))->name() !=
+Klass::cast((klassOop) k_new_interfaces->obj_at(i))->name()) {
+return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
+}
+}
+// Check whether class is in the error init state.
+if (the_class->is_in_error_state()) {
+// TBD #5057930: special error code is needed in 1.6
+return JVMTI_ERROR_INVALID_CLASS;
+}
+// Check whether class modifiers are the same.
+jushort old_flags = (jushort) the_class->access_flags().get_flags();
+jushort new_flags = (jushort) scratch_class->access_flags().get_flags();
+if (old_flags != new_flags) {
+return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_MODIFIERS_CHANGED;
+}
+// Check if the number, names, types and order of fields declared in these classes
+// are the same.
+typeArrayOop k_old_fields = the_class->fields();
+typeArrayOop k_new_fields = scratch_class->fields();
+int n_fields = k_old_fields->length();
+if (n_fields != k_new_fields->length()) {
+return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
+}
+for (i = 0; i < n_fields; i += instanceKlass::next_offset) {
+// access
+old_flags = k_old_fields->ushort_at(i + instanceKlass::access_flags_offset);
+new_flags = k_new_fields->ushort_at(i + instanceKlass::access_flags_offset);
+if ((old_flags ^ new_flags) & JVM_RECOGNIZED_FIELD_MODIFIERS) {
+return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
+}
+// offset
+if (k_old_fields->short_at(i + instanceKlass::low_offset) !=
+k_new_fields->short_at(i + instanceKlass::low_offset) ||
+k_old_fields->short_at(i + instanceKlass::high_offset) !=
+k_new_fields->short_at(i + instanceKlass::high_offset)) {
+return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
+}
+// name and signature
+jshort name_index = k_old_fields->short_at(i + instanceKlass::name_index_offset);
+jshort sig_index = k_old_fields->short_at(i +instanceKlass::signature_index_offset);
+symbolOop name_sym1 = the_class->constants()->symbol_at(name_index);
+symbolOop sig_sym1 = the_class->constants()->symbol_at(sig_index);
+name_index = k_new_fields->short_at(i + instanceKlass::name_index_offset);
+sig_index = k_new_fields->short_at(i + instanceKlass::signature_index_offset);
+symbolOop name_sym2 = scratch_class->constants()->symbol_at(name_index);
+symbolOop sig_sym2 = scratch_class->constants()->symbol_at(sig_index);
+if (name_sym1 != name_sym2 || sig_sym1 != sig_sym2) {
+return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
+}
+}
+// Do a parallel walk through the old and new methods. Detect
+// cases where they match (exist in both), have been added in
+// the new methods, or have been deleted (exist only in the
+// old methods).  The class file parser places methods in order
+// by method name, but does not order overloaded methods by
+// signature.  In order to determine what fate befell the methods,
+// this code places the overloaded new methods that have matching
+// old methods in the same order as the old methods and places
+// new overloaded methods at the end of overloaded methods of
+// that name. The code for this order normalization is adapted
+// from the algorithm used in instanceKlass::find_method().
+// Since we are swapping out of order entries as we find them,
+// we only have to search forward through the overloaded methods.
+// Methods which are added and have the same name as an existing
+// method (but different signature) will be put at the end of
+// the methods with that name, and the name mismatch code will
+// handle them.
+objArrayHandle k_old_methods(the_class->methods());
+objArrayHandle k_new_methods(scratch_class->methods());
+int n_old_methods = k_old_methods->length();
+int n_new_methods = k_new_methods->length();
+int ni = 0;
+int oi = 0;
+while (true) {
+methodOop k_old_method;
+methodOop k_new_method;
+enum { matched, added, deleted, undetermined } method_was = undetermined;
+if (oi >= n_old_methods) {
+if (ni >= n_new_methods) {
+break; // we've looked at everything, done
+}
+// New method at the end
+k_new_method = (methodOop) k_new_methods->obj_at(ni);
+method_was = added;
+} else if (ni >= n_new_methods) {
+// Old method, at the end, is deleted
+k_old_method = (methodOop) k_old_methods->obj_at(oi);
+method_was = deleted;
+} else {
+// There are more methods in both the old and new lists
+k_old_method = (methodOop) k_old_methods->obj_at(oi);
+k_new_method = (methodOop) k_new_methods->obj_at(ni);
+if (k_old_method->name() != k_new_method->name()) {
+// Methods are sorted by method name, so a mismatch means added
+// or deleted
+if (k_old_method->name()->fast_compare(k_new_method->name()) > 0) {
+method_was = added;
+} else {
+method_was = deleted;
+}
+} else if (k_old_method->signature() == k_new_method->signature()) {
+// Both the name and signature match
+method_was = matched;
+} else {
+// The name matches, but the signature doesn't, which means we have to
+// search forward through the new overloaded methods.
+int nj;  // outside the loop for post-loop check
+for (nj = ni + 1; nj < n_new_methods; nj++) {
+methodOop m = (methodOop)k_new_methods->obj_at(nj);
+if (k_old_method->name() != m->name()) {
+// reached another method name so no more overloaded methods
+method_was = deleted;
+break;
+}
+if (k_old_method->signature() == m->signature()) {
+// found a match so swap the methods
+k_new_methods->obj_at_put(ni, m);
+k_new_methods->obj_at_put(nj, k_new_method);
+k_new_method = m;
+method_was = matched;
+break;
+}
+}
+if (nj >= n_new_methods) {
+// reached the end without a match; so method was deleted
+method_was = deleted;
+}
+}
+}
+switch (method_was) {
+case matched:
+// methods match, be sure modifiers do too
+old_flags = (jushort) k_old_method->access_flags().get_flags();
+new_flags = (jushort) k_new_method->access_flags().get_flags();
+if ((old_flags ^ new_flags) & ~(JVM_ACC_NATIVE)) {
+return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_MODIFIERS_CHANGED;
+}
+{
+u2 new_num = k_new_method->method_idnum();
+u2 old_num = k_old_method->method_idnum();
+if (new_num != old_num) {
+methodOop idnum_owner = scratch_class->method_with_idnum(old_num);
+if (idnum_owner != NULL) {
+// There is already a method assigned this idnum -- switch them
+idnum_owner->set_method_idnum(new_num);
+}
+k_new_method->set_method_idnum(old_num);
+swap_all_method_annotations(old_num, new_num, scratch_class);
+}
+}
+RC_TRACE(0x00008000, ("Method matched: new: %s [%d] == old: %s [%d]",
+k_new_method->name_and_sig_as_C_string(), ni,
+k_old_method->name_and_sig_as_C_string(), oi));
+// advance to next pair of methods
+++oi;
+++ni;
+break;
+case added:
+// method added, see if it is OK
+new_flags = (jushort) k_new_method->access_flags().get_flags();
+if ((new_flags & JVM_ACC_PRIVATE) == 0
+// hack: private should be treated as final, but alas
+|| (new_flags & (JVM_ACC_FINAL|JVM_ACC_STATIC)) == 0
+) {
+// new methods must be private
+return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED;
+}
+{
+u2 num = the_class->next_method_idnum();
+if (num == constMethodOopDesc::UNSET_IDNUM) {
+// cannot add any more methods
+return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED;
+}
+u2 new_num = k_new_method->method_idnum();
+methodOop idnum_owner = scratch_class->method_with_idnum(num);
+if (idnum_owner != NULL) {
+// There is already a method assigned this idnum -- switch them
+idnum_owner->set_method_idnum(new_num);
+}
+k_new_method->set_method_idnum(num);
+swap_all_method_annotations(new_num, num, scratch_class);
+}
+RC_TRACE(0x00008000, ("Method added: new: %s [%d]",
+k_new_method->name_and_sig_as_C_string(), ni));
+++ni; // advance to next new method
+break;
+case deleted:
+// method deleted, see if it is OK
+old_flags = (jushort) k_old_method->access_flags().get_flags();
+if ((old_flags & JVM_ACC_PRIVATE) == 0
+// hack: private should be treated as final, but alas
+|| (old_flags & (JVM_ACC_FINAL|JVM_ACC_STATIC)) == 0
+) {
+// deleted methods must be private
+return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_DELETED;
+}
+RC_TRACE(0x00008000, ("Method deleted: old: %s [%d]",
+k_old_method->name_and_sig_as_C_string(), oi));
+++oi; // advance to next old method
+break;
+default:
+ShouldNotReachHere();
+}
+}
+return JVMTI_ERROR_NONE;
+}
+// Find new constant pool index value for old constant pool index value
+// by seaching the index map. Returns zero (0) if there is no mapped
+// value for the old constant pool index.
+int VM_RedefineClasses::find_new_index(int old_index) {
+if (_index_map_count == 0) {
+// map is empty so nothing can be found
+return 0;
+}
+if (old_index < 1 || old_index >= _index_map_p->length()) {
+// The old_index is out of range so it is not mapped. This should
+// not happen in regular constant pool merging use, but it can
+// happen if a corrupt annotation is processed.
+return 0;
+}
+int value = _index_map_p->at(old_index);
+if (value == -1) {
+// the old_index is not mapped
+return 0;
+}
+return value;
+} // end find_new_index()
+// Returns true if the current mismatch is due to a resolved/unresolved
+// class pair. Otherwise, returns false.
+bool VM_RedefineClasses::is_unresolved_class_mismatch(constantPoolHandle cp1,
+int index1, constantPoolHandle cp2, int index2) {
+jbyte t1 = cp1->tag_at(index1).value();
+if (t1 != JVM_CONSTANT_Class && t1 != JVM_CONSTANT_UnresolvedClass) {
+return false;  // wrong entry type; not our special case
+}
+jbyte t2 = cp2->tag_at(index2).value();
+if (t2 != JVM_CONSTANT_Class && t2 != JVM_CONSTANT_UnresolvedClass) {
+return false;  // wrong entry type; not our special case
+}
+if (t1 == t2) {
+return false;  // not a mismatch; not our special case
+}
+char *s1 = cp1->klass_name_at(index1)->as_C_string();
+char *s2 = cp2->klass_name_at(index2)->as_C_string();
+if (strcmp(s1, s2) != 0) {
+return false;  // strings don't match; not our special case
+}
+return true;  // made it through the gauntlet; this is our special case
+} // end is_unresolved_class_mismatch()
+// Returns true if the current mismatch is due to a resolved/unresolved
+// string pair. Otherwise, returns false.
+bool VM_RedefineClasses::is_unresolved_string_mismatch(constantPoolHandle cp1,
+int index1, constantPoolHandle cp2, int index2) {
+jbyte t1 = cp1->tag_at(index1).value();
+if (t1 != JVM_CONSTANT_String && t1 != JVM_CONSTANT_UnresolvedString) {
+return false;  // wrong entry type; not our special case
+}
+jbyte t2 = cp2->tag_at(index2).value();
+if (t2 != JVM_CONSTANT_String && t2 != JVM_CONSTANT_UnresolvedString) {
+return false;  // wrong entry type; not our special case
+}
+if (t1 == t2) {
+return false;  // not a mismatch; not our special case
+}
+char *s1 = cp1->string_at_noresolve(index1);
+char *s2 = cp2->string_at_noresolve(index2);
+if (strcmp(s1, s2) != 0) {
+return false;  // strings don't match; not our special case
+}
+return true;  // made it through the gauntlet; this is our special case
+} // end is_unresolved_string_mismatch()
+jvmtiError VM_RedefineClasses::load_new_class_versions(TRAPS) {
+// For consistency allocate memory using os::malloc wrapper.
+_scratch_classes = (instanceKlassHandle *)
+os::malloc(sizeof(instanceKlassHandle) * _class_count);
+if (_scratch_classes == NULL) {
+return JVMTI_ERROR_OUT_OF_MEMORY;
+}
+ResourceMark rm(THREAD);
+JvmtiThreadState *state = JvmtiThreadState::state_for(JavaThread::current());
+for (int i = 0; i < _class_count; i++) {
+oop mirror = JNIHandles::resolve_non_null(_class_defs[i].klass);
+// classes for primitives cannot be redefined
+if (!is_modifiable_class(mirror)) {
+return JVMTI_ERROR_UNMODIFIABLE_CLASS;
+}
+klassOop the_class_oop = java_lang_Class::as_klassOop(mirror);
+instanceKlassHandle the_class = instanceKlassHandle(THREAD, the_class_oop);
+symbolHandle the_class_sym = symbolHandle(THREAD, the_class->name());
+// RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
+RC_TRACE_WITH_THREAD(0x00000001, THREAD,
+("loading name=%s (avail_mem=" UINT64_FORMAT "K)",
+the_class->external_name(), os::available_memory() >> 10));
+ClassFileStream st((u1*) _class_defs[i].class_bytes,
+_class_defs[i].class_byte_count, (char *)"__VM_RedefineClasses__");
+// Parse the stream.
+Handle the_class_loader(THREAD, the_class->class_loader());
+Handle protection_domain(THREAD, the_class->protection_domain());
+// Set redefined class handle in JvmtiThreadState class.
+// This redefined class is sent to agent event handler for class file
+// load hook event.
+state->set_class_being_redefined(&the_class, _class_load_kind);
+klassOop k = SystemDictionary::parse_stream(the_class_sym,
+the_class_loader,
+protection_domain,
+&st,
+THREAD);
+// Clear class_being_redefined just to be sure.
+state->clear_class_being_redefined();
+// TODO: if this is retransform, and nothing changed we can skip it
+instanceKlassHandle scratch_class (THREAD, k);
+if (HAS_PENDING_EXCEPTION) {
+symbolOop ex_name = PENDING_EXCEPTION->klass()->klass_part()->name();
+// RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
+RC_TRACE_WITH_THREAD(0x00000002, THREAD, ("parse_stream exception: '%s'",
+ex_name->as_C_string()));
+CLEAR_PENDING_EXCEPTION;
+if (ex_name == vmSymbols::java_lang_UnsupportedClassVersionError()) {
+return JVMTI_ERROR_UNSUPPORTED_VERSION;
+} else if (ex_name == vmSymbols::java_lang_ClassFormatError()) {
+return JVMTI_ERROR_INVALID_CLASS_FORMAT;
+} else if (ex_name == vmSymbols::java_lang_ClassCircularityError()) {
+return JVMTI_ERROR_CIRCULAR_CLASS_DEFINITION;
+} else if (ex_name == vmSymbols::java_lang_NoClassDefFoundError()) {
+// The message will be "XXX (wrong name: YYY)"
+return JVMTI_ERROR_NAMES_DONT_MATCH;
+} else if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
+return JVMTI_ERROR_OUT_OF_MEMORY;
+} else {  // Just in case more exceptions can be thrown..
+return JVMTI_ERROR_FAILS_VERIFICATION;
+}
+}
+// Ensure class is linked before redefine
+if (!the_class->is_linked()) {
+the_class->link_class(THREAD);
+if (HAS_PENDING_EXCEPTION) {
+symbolOop ex_name = PENDING_EXCEPTION->klass()->klass_part()->name();
+// RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
+RC_TRACE_WITH_THREAD(0x00000002, THREAD, ("link_class exception: '%s'",
+ex_name->as_C_string()));
+CLEAR_PENDING_EXCEPTION;
+if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
+return JVMTI_ERROR_OUT_OF_MEMORY;
+} else {
+return JVMTI_ERROR_INTERNAL;
+}
+}
+}
+// Do the validity checks in compare_and_normalize_class_versions()
+// before verifying the byte codes. By doing these checks first, we
+// limit the number of functions that require redirection from
+// the_class to scratch_class. In particular, we don't have to
+// modify JNI GetSuperclass() and thus won't change its performance.
+jvmtiError res = compare_and_normalize_class_versions(the_class,
+scratch_class);
+if (res != JVMTI_ERROR_NONE) {
+return res;
+}
+// verify what the caller passed us
+{
+// The bug 6214132 caused the verification to fail.
+// Information about the_class and scratch_class is temporarily
+// recorded into jvmtiThreadState. This data is used to redirect
+// the_class to scratch_class in the JVM_* functions called by the
+// verifier. Please, refer to jvmtiThreadState.hpp for the detailed
+// description.
+RedefineVerifyMark rvm(&the_class, &scratch_class, state);
+Verifier::verify(
+scratch_class, Verifier::ThrowException, THREAD);
+}
+if (HAS_PENDING_EXCEPTION) {
+symbolOop ex_name = PENDING_EXCEPTION->klass()->klass_part()->name();
+// RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
+RC_TRACE_WITH_THREAD(0x00000002, THREAD,
+("verify_byte_codes exception: '%s'", ex_name->as_C_string()));
+CLEAR_PENDING_EXCEPTION;
+if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
+return JVMTI_ERROR_OUT_OF_MEMORY;
+} else {
+// tell the caller the bytecodes are bad
+return JVMTI_ERROR_FAILS_VERIFICATION;
+}
+}
+res = merge_cp_and_rewrite(the_class, scratch_class, THREAD);
+if (res != JVMTI_ERROR_NONE) {
+return res;
+}
+if (VerifyMergedCPBytecodes) {
+// verify what we have done during constant pool merging
+{
+RedefineVerifyMark rvm(&the_class, &scratch_class, state);
+Verifier::verify(scratch_class, Verifier::ThrowException, THREAD);
+}
+if (HAS_PENDING_EXCEPTION) {
+symbolOop ex_name = PENDING_EXCEPTION->klass()->klass_part()->name();
+// RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
+RC_TRACE_WITH_THREAD(0x00000002, THREAD,
+("verify_byte_codes post merge-CP exception: '%s'",
+ex_name->as_C_string()));
+CLEAR_PENDING_EXCEPTION;
+if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
+return JVMTI_ERROR_OUT_OF_MEMORY;
+} else {
+// tell the caller that constant pool merging screwed up
+return JVMTI_ERROR_INTERNAL;
+}
+}
+}
+Rewriter::rewrite(scratch_class, THREAD);
+if (HAS_PENDING_EXCEPTION) {
+symbolOop ex_name = PENDING_EXCEPTION->klass()->klass_part()->name();
+CLEAR_PENDING_EXCEPTION;
+if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
+return JVMTI_ERROR_OUT_OF_MEMORY;
+} else {
+return JVMTI_ERROR_INTERNAL;
+}
+}
+_scratch_classes[i] = scratch_class;
+// RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
+RC_TRACE_WITH_THREAD(0x00000001, THREAD,
+("loaded name=%s (avail_mem=" UINT64_FORMAT "K)",
+the_class->external_name(), os::available_memory() >> 10));
+}
+return JVMTI_ERROR_NONE;
+}
+// Map old_index to new_index as needed. scratch_cp is only needed
+// for RC_TRACE() calls.
+void VM_RedefineClasses::map_index(constantPoolHandle scratch_cp,
+int old_index, int new_index) {
+if (find_new_index(old_index) != 0) {
+// old_index is already mapped
+return;
+}
+if (old_index == new_index) {
+// no mapping is needed
+return;
+}
+_index_map_p->at_put(old_index, new_index);
+_index_map_count++;
+RC_TRACE(0x00040000, ("mapped tag %d at index %d to %d",
+scratch_cp->tag_at(old_index).value(), old_index, new_index));
+} // end map_index()
+// Merge old_cp and scratch_cp and return the results of the merge via
+// merge_cp_p. The number of entries in *merge_cp_p is returned via
+// merge_cp_length_p. The entries in old_cp occupy the same locations
+// in *merge_cp_p. Also creates a map of indices from entries in
+// scratch_cp to the corresponding entry in *merge_cp_p. Index map
+// entries are only created for entries in scratch_cp that occupy a
+// different location in *merged_cp_p.
+bool VM_RedefineClasses::merge_constant_pools(constantPoolHandle old_cp,
+constantPoolHandle scratch_cp, constantPoolHandle *merge_cp_p,
+int *merge_cp_length_p, TRAPS) {
+if (merge_cp_p == NULL) {
+assert(false, "caller must provide scatch constantPool");
+return false; // robustness
+}
+if (merge_cp_length_p == NULL) {
+assert(false, "caller must provide scatch CP length");
+return false; // robustness
+}
+// Worst case we need old_cp->length() + scratch_cp()->length(),
+// but the caller might be smart so make sure we have at least
+// the minimum.
+if ((*merge_cp_p)->length() < old_cp->length()) {
+assert(false, "merge area too small");
+return false; // robustness
+}
+RC_TRACE_WITH_THREAD(0x00010000, THREAD,
+("old_cp_len=%d, scratch_cp_len=%d", old_cp->length(),
+scratch_cp->length()));
+{
+// Pass 0:
+// The old_cp is copied to *merge_cp_p; this means that any code
+// using old_cp does not have to change. This work looks like a
+// perfect fit for constantPoolOop::copy_cp_to(), but we need to
+// handle one special case:
+// - revert JVM_CONSTANT_Class to JVM_CONSTANT_UnresolvedClass
+// This will make verification happy.
+int old_i;  // index into old_cp
+// index zero (0) is not used in constantPools
+for (old_i = 1; old_i < old_cp->length(); old_i++) {
+// leave debugging crumb
+jbyte old_tag = old_cp->tag_at(old_i).value();
+switch (old_tag) {
+case JVM_CONSTANT_Class:
+// revert the copy to JVM_CONSTANT_UnresolvedClass
+(*merge_cp_p)->unresolved_klass_at_put(old_i,
+old_cp->klass_name_at(old_i));
+break;
+case JVM_CONSTANT_Double:
+case JVM_CONSTANT_Long:
+// just copy the entry to *merge_cp_p, but double and long take
+// two constant pool entries
+old_cp->copy_entry_to(old_i, *merge_cp_p, old_i, CHECK_0);
+old_i++;
+break;
+default:
+// just copy the entry to *merge_cp_p
+old_cp->copy_entry_to(old_i, *merge_cp_p, old_i, CHECK_0);
+break;
+}
+} // end for each old_cp entry
+// We don't need to sanity check that *merge_cp_length_p is within
+// *merge_cp_p bounds since we have the minimum on-entry check above.
+(*merge_cp_length_p) = old_i;
+}
+// merge_cp_len should be the same as old_cp->length() at this point
+// so this trace message is really a "warm-and-breathing" message.
+RC_TRACE_WITH_THREAD(0x00020000, THREAD,
+("after pass 0: merge_cp_len=%d", *merge_cp_length_p));
+int scratch_i;  // index into scratch_cp
+{
+// Pass 1a:
+// Compare scratch_cp entries to the old_cp entries that we have
+// already copied to *merge_cp_p. In this pass, we are eliminating
+// exact duplicates (matching entry at same index) so we only
+// compare entries in the common indice range.
+int increment = 1;
+int pass1a_length = MIN2(old_cp->length(), scratch_cp->length());
+for (scratch_i = 1; scratch_i < pass1a_length; scratch_i += increment) {
+switch (scratch_cp->tag_at(scratch_i).value()) {
+case JVM_CONSTANT_Double:
+case JVM_CONSTANT_Long:
+// double and long take two constant pool entries
+increment = 2;
+break;
+default:
+increment = 1;
+break;
+}
+bool match = scratch_cp->compare_entry_to(scratch_i, *merge_cp_p,
+scratch_i, CHECK_0);
+if (match) {
+// found a match at the same index so nothing more to do
+continue;
+} else if (is_unresolved_class_mismatch(scratch_cp, scratch_i,
+*merge_cp_p, scratch_i)) {
+// The mismatch in compare_entry_to() above is because of a
+// resolved versus unresolved class entry at the same index
+// with the same string value. Since Pass 0 reverted any
+// class entries to unresolved class entries in *merge_cp_p,
+// we go with the unresolved class entry.
+continue;
+} else if (is_unresolved_string_mismatch(scratch_cp, scratch_i,
+*merge_cp_p, scratch_i)) {
+// The mismatch in compare_entry_to() above is because of a
+// resolved versus unresolved string entry at the same index
+// with the same string value. We can live with whichever
+// happens to be at scratch_i in *merge_cp_p.
+continue;
+}
+int found_i = scratch_cp->find_matching_entry(scratch_i, *merge_cp_p,
+CHECK_0);
+if (found_i != 0) {
+guarantee(found_i != scratch_i,
+"compare_entry_to() and find_matching_entry() do not agree");
+// Found a matching entry somewhere else in *merge_cp_p so
+// just need a mapping entry.
+map_index(scratch_cp, scratch_i, found_i);
+continue;
+}
+// The find_matching_entry() call above could fail to find a match
+// due to a resolved versus unresolved class or string entry situation
+// like we solved above with the is_unresolved_*_mismatch() calls.
+// However, we would have to call is_unresolved_*_mismatch() over
+// all of *merge_cp_p (potentially) and that doesn't seem to be
+// worth the time.
+// No match found so we have to append this entry and any unique
+// referenced entries to *merge_cp_p.
+append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p,
+CHECK_0);
+}
+}
+RC_TRACE_WITH_THREAD(0x00020000, THREAD,
+("after pass 1a: merge_cp_len=%d, scratch_i=%d, index_map_len=%d",
+*merge_cp_length_p, scratch_i, _index_map_count));
+if (scratch_i < scratch_cp->length()) {
+// Pass 1b:
+// old_cp is smaller than scratch_cp so there are entries in
+// scratch_cp that we have not yet processed. We take care of
+// those now.
+int increment = 1;
+for (; scratch_i < scratch_cp->length(); scratch_i += increment) {
+switch (scratch_cp->tag_at(scratch_i).value()) {
+case JVM_CONSTANT_Double:
+case JVM_CONSTANT_Long:
+// double and long take two constant pool entries
+increment = 2;
+break;
+default:
+increment = 1;
+break;
+}
+int found_i =
+scratch_cp->find_matching_entry(scratch_i, *merge_cp_p, CHECK_0);
+if (found_i != 0) {
+// Found a matching entry somewhere else in *merge_cp_p so
+// just need a mapping entry.
+map_index(scratch_cp, scratch_i, found_i);
+continue;
+}
+// No match found so we have to append this entry and any unique
+// referenced entries to *merge_cp_p.
+append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p,
+CHECK_0);
+}
+RC_TRACE_WITH_THREAD(0x00020000, THREAD,
+("after pass 1b: merge_cp_len=%d, scratch_i=%d, index_map_len=%d",
+*merge_cp_length_p, scratch_i, _index_map_count));
+}
+return true;
+} // end merge_constant_pools()
+// Merge constant pools between the_class and scratch_class and
+// potentially rewrite bytecodes in scratch_class to use the merged
+// constant pool.
+jvmtiError VM_RedefineClasses::merge_cp_and_rewrite(
+instanceKlassHandle the_class, instanceKlassHandle scratch_class,
+TRAPS) {
+// worst case merged constant pool length is old and new combined
+int merge_cp_length = the_class->constants()->length()
++ scratch_class->constants()->length();
+constantPoolHandle old_cp(THREAD, the_class->constants());
+constantPoolHandle scratch_cp(THREAD, scratch_class->constants());
+// Constant pools are not easily reused so we allocate a new one
+// each time.
+constantPoolHandle merge_cp(THREAD,
+oopFactory::new_constantPool(merge_cp_length, THREAD));
+int orig_length = old_cp->orig_length();
+if (orig_length == 0) {
+// This old_cp is an actual original constant pool. We save
+// the original length in the merged constant pool so that
+// merge_constant_pools() can be more efficient. If a constant
+// pool has a non-zero orig_length() value, then that constant
+// pool was created by a merge operation in RedefineClasses.
+merge_cp->set_orig_length(old_cp->length());
+} else {
+// This old_cp is a merged constant pool from a previous
+// RedefineClasses() calls so just copy the orig_length()
+// value.
+merge_cp->set_orig_length(old_cp->orig_length());
+}
+ResourceMark rm(THREAD);
+_index_map_count = 0;
+_index_map_p = new intArray(scratch_cp->length(), -1);
+bool result = merge_constant_pools(old_cp, scratch_cp, &merge_cp,
+&merge_cp_length, THREAD);
+if (!result) {
+// The merge can fail due to memory allocation failure or due
+// to robustness checks.
+return JVMTI_ERROR_INTERNAL;
+}
+RC_TRACE_WITH_THREAD(0x00010000, THREAD,
+("merge_cp_len=%d, index_map_len=%d", merge_cp_length, _index_map_count));
+if (_index_map_count == 0) {
+// there is nothing to map between the new and merged constant pools
+if (old_cp->length() == scratch_cp->length()) {
+// The old and new constant pools are the same length and the
+// index map is empty. This means that the three constant pools
+// are equivalent (but not the same). Unfortunately, the new
+// constant pool has not gone through link resolution nor have
+// the new class bytecodes gone through constant pool cache
+// rewriting so we can't use the old constant pool with the new
+// class.
+merge_cp = constantPoolHandle();  // toss the merged constant pool
+} else if (old_cp->length() < scratch_cp->length()) {
+// The old constant pool has fewer entries than the new constant
+// pool and the index map is empty. This means the new constant
+// pool is a superset of the old constant pool. However, the old
+// class bytecodes have already gone through constant pool cache
+// rewriting so we can't use the new constant pool with the old
+// class.
+merge_cp = constantPoolHandle();  // toss the merged constant pool
+} else {
+// The old constant pool has more entries than the new constant
+// pool and the index map is empty. This means that both the old
+// and merged constant pools are supersets of the new constant
+// pool.
+// Replace the new constant pool with a shrunken copy of the
+// merged constant pool; the previous new constant pool will
+// get GCed.
+set_new_constant_pool(scratch_class, merge_cp, merge_cp_length, true,
+THREAD);
+// drop local ref to the merged constant pool
+merge_cp = constantPoolHandle();
+}
+} else {
+if (RC_TRACE_ENABLED(0x00040000)) {
+// don't want to loop unless we are tracing
+int count = 0;
+for (int i = 1; i < _index_map_p->length(); i++) {
+int value = _index_map_p->at(i);
+if (value != -1) {
+RC_TRACE_WITH_THREAD(0x00040000, THREAD,
+("index_map[%d]: old=%d new=%d", count, i, value));
+count++;
+}
+}
+}
+// We have entries mapped between the new and merged constant pools
+// so we have to rewrite some constant pool references.
+if (!rewrite_cp_refs(scratch_class, THREAD)) {
+return JVMTI_ERROR_INTERNAL;
+}
+// Replace the new constant pool with a shrunken copy of the
+// merged constant pool so now the rewritten bytecodes have
+// valid references; the previous new constant pool will get
+// GCed.
+set_new_constant_pool(scratch_class, merge_cp, merge_cp_length, true,
+THREAD);
+}
+return JVMTI_ERROR_NONE;
+} // end merge_cp_and_rewrite()
+// Rewrite constant pool references in klass scratch_class.
+bool VM_RedefineClasses::rewrite_cp_refs(instanceKlassHandle scratch_class,
+TRAPS) {
+// rewrite constant pool references in the methods:
+if (!rewrite_cp_refs_in_methods(scratch_class, THREAD)) {
+// propogate failure back to caller
+return false;
+}
+// rewrite constant pool references in the class_annotations:
+if (!rewrite_cp_refs_in_class_annotations(scratch_class, THREAD)) {
+// propogate failure back to caller
+return false;
+}
+// rewrite constant pool references in the fields_annotations:
+if (!rewrite_cp_refs_in_fields_annotations(scratch_class, THREAD)) {
+// propogate failure back to caller
+return false;
+}
+// rewrite constant pool references in the methods_annotations:
+if (!rewrite_cp_refs_in_methods_annotations(scratch_class, THREAD)) {
+// propogate failure back to caller
+return false;
+}
+// rewrite constant pool references in the methods_parameter_annotations:
+if (!rewrite_cp_refs_in_methods_parameter_annotations(scratch_class,
+THREAD)) {
+// propogate failure back to caller
+return false;
+}
+// rewrite constant pool references in the methods_default_annotations:
+if (!rewrite_cp_refs_in_methods_default_annotations(scratch_class,
+THREAD)) {
+// propogate failure back to caller
+return false;
+}
+return true;
+} // end rewrite_cp_refs()
+// Rewrite constant pool references in the methods.
+bool VM_RedefineClasses::rewrite_cp_refs_in_methods(
+instanceKlassHandle scratch_class, TRAPS) {
+objArrayHandle methods(THREAD, scratch_class->methods());
+if (methods.is_null() || methods->length() == 0) {
+// no methods so nothing to do
+return true;
+}
+// rewrite constant pool references in the methods:
+for (int i = methods->length() - 1; i >= 0; i--) {
+methodHandle method(THREAD, (methodOop)methods->obj_at(i));
+methodHandle new_method;
+rewrite_cp_refs_in_method(method, &new_method, CHECK_false);
+if (!new_method.is_null()) {
+// the method has been replaced so save the new method version
+methods->obj_at_put(i, new_method());
+}
+}
+return true;
+}
+// Rewrite constant pool references in the specific method. This code
+// was adapted from Rewriter::rewrite_method().
+void VM_RedefineClasses::rewrite_cp_refs_in_method(methodHandle method,
+methodHandle *new_method_p, TRAPS) {
+*new_method_p = methodHandle();  // default is no new method
+// We cache a pointer to the bytecodes here in code_base. If GC
+// moves the methodOop, then the bytecodes will also move which
+// will likely cause a crash. We create a No_Safepoint_Verifier
+// object to detect whether we pass a possible safepoint in this
+// code block.
+No_Safepoint_Verifier nsv;
+// Bytecodes and their length
+address code_base = method->code_base();
+int code_length = method->code_size();
+int bc_length;
+for (int bci = 0; bci < code_length; bci += bc_length) {
+address bcp = code_base + bci;
+Bytecodes::Code c = (Bytecodes::Code)(*bcp);
+bc_length = Bytecodes::length_for(c);
+if (bc_length == 0) {
+// More complicated bytecodes report a length of zero so
+// we have to try again a slightly different way.
+bc_length = Bytecodes::length_at(bcp);
+}
+assert(bc_length != 0, "impossible bytecode length");
+switch (c) {
+case Bytecodes::_ldc:
+{
+int cp_index = *(bcp + 1);
+int new_index = find_new_index(cp_index);
+if (StressLdcRewrite && new_index == 0) {
+// If we are stressing ldc -> ldc_w rewriting, then we
+// always need a new_index value.
+new_index = cp_index;
+}
+if (new_index != 0) {
+// the original index is mapped so we have more work to do
+if (!StressLdcRewrite && new_index <= max_jubyte) {
+// The new value can still use ldc instead of ldc_w
+// unless we are trying to stress ldc -> ldc_w rewriting
+RC_TRACE_WITH_THREAD(0x00080000, THREAD,
+("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c),
+bcp, cp_index, new_index));
+*(bcp + 1) = new_index;
+} else {
+RC_TRACE_WITH_THREAD(0x00080000, THREAD,
+("%s->ldc_w@" INTPTR_FORMAT " old=%d, new=%d",
+Bytecodes::name(c), bcp, cp_index, new_index));
+// the new value needs ldc_w instead of ldc
+u_char inst_buffer[4]; // max instruction size is 4 bytes
+bcp = (address)inst_buffer;
+// construct new instruction sequence
+*bcp = Bytecodes::_ldc_w;
+bcp++;
+// Rewriter::rewrite_method() does not rewrite ldc -> ldc_w.
+// See comment below for difference between put_Java_u2()
+// and put_native_u2().
+Bytes::put_Java_u2(bcp, new_index);
+Relocator rc(method, NULL /* no RelocatorListener needed */);
+methodHandle m;
+{
+Pause_No_Safepoint_Verifier pnsv(&nsv);
+// ldc is 2 bytes and ldc_w is 3 bytes
+m = rc.insert_space_at(bci, 3, inst_buffer, THREAD);
+if (m.is_null() || HAS_PENDING_EXCEPTION) {
+guarantee(false, "insert_space_at() failed");
+}
+}
+// return the new method so that the caller can update
+// the containing class
+*new_method_p = method = m;
+// switch our bytecode processing loop from the old method
+// to the new method
+code_base = method->code_base();
+code_length = method->code_size();
+bcp = code_base + bci;
+c = (Bytecodes::Code)(*bcp);
+bc_length = Bytecodes::length_for(c);
+assert(bc_length != 0, "sanity check");
+} // end we need ldc_w instead of ldc
+} // end if there is a mapped index
+} break;
+// these bytecodes have a two-byte constant pool index
+case Bytecodes::_anewarray      : // fall through
+case Bytecodes::_checkcast      : // fall through
+case Bytecodes::_getfield       : // fall through
+case Bytecodes::_getstatic      : // fall through
+case Bytecodes::_instanceof     : // fall through
+case Bytecodes::_invokeinterface: // fall through
+case Bytecodes::_invokespecial  : // fall through
+case Bytecodes::_invokestatic   : // fall through
+case Bytecodes::_invokevirtual  : // fall through
+case Bytecodes::_ldc_w          : // fall through
+case Bytecodes::_ldc2_w         : // fall through
+case Bytecodes::_multianewarray : // fall through
+case Bytecodes::_new            : // fall through
+case Bytecodes::_putfield       : // fall through
+case Bytecodes::_putstatic      :
+{
+address p = bcp + 1;
+int cp_index = Bytes::get_Java_u2(p);
+int new_index = find_new_index(cp_index);
+if (new_index != 0) {
+// the original index is mapped so update w/ new value
+RC_TRACE_WITH_THREAD(0x00080000, THREAD,
+("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c),
+bcp, cp_index, new_index));
+// Rewriter::rewrite_method() uses put_native_u2() in this
+// situation because it is reusing the constant pool index
+// location for a native index into the constantPoolCache.
+// Since we are updating the constant pool index prior to
+// verification and constantPoolCache initialization, we
+// need to keep the new index in Java byte order.
+Bytes::put_Java_u2(p, new_index);
+}
+} break;
+}
+} // end for each bytecode
+} // end rewrite_cp_refs_in_method()
+// Rewrite constant pool references in the class_annotations field.
+bool VM_RedefineClasses::rewrite_cp_refs_in_class_annotations(
+instanceKlassHandle scratch_class, TRAPS) {
+typeArrayHandle class_annotations(THREAD,
+scratch_class->class_annotations());
+if (class_annotations.is_null() || class_annotations->length() == 0) {
+// no class_annotations so nothing to do
+return true;
+}
+RC_TRACE_WITH_THREAD(0x02000000, THREAD,
+("class_annotations length=%d", class_annotations->length()));
+int byte_i = 0;  // byte index into class_annotations
+return rewrite_cp_refs_in_annotations_typeArray(class_annotations, byte_i,
+THREAD);
+}
+// Rewrite constant pool references in an annotations typeArray. This
+// "structure" is adapted from the RuntimeVisibleAnnotations_attribute
+// that is described in section 4.8.15 of the 2nd-edition of the VM spec:
+//
+// annotations_typeArray {
+//   u2 num_annotations;
+//   annotation annotations[num_annotations];
+// }
+//
+bool VM_RedefineClasses::rewrite_cp_refs_in_annotations_typeArray(
+typeArrayHandle annotations_typeArray, int &byte_i_ref, TRAPS) {
+if ((byte_i_ref + 2) > annotations_typeArray->length()) {
+// not enough room for num_annotations field
+RC_TRACE_WITH_THREAD(0x02000000, THREAD,
+("length() is too small for num_annotations field"));
+return false;
+}
+u2 num_annotations = Bytes::get_Java_u2((address)
+annotations_typeArray->byte_at_addr(byte_i_ref));
+byte_i_ref += 2;
+RC_TRACE_WITH_THREAD(0x02000000, THREAD,
+("num_annotations=%d", num_annotations));
+int calc_num_annotations = 0;
+for (; calc_num_annotations < num_annotations; calc_num_annotations++) {
+if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray,
+byte_i_ref, THREAD)) {
+RC_TRACE_WITH_THREAD(0x02000000, THREAD,
+("bad annotation_struct at %d", calc_num_annotations));
+// propogate failure back to caller
+return false;
+}
+}
+assert(num_annotations == calc_num_annotations, "sanity check");
+return true;
+} // end rewrite_cp_refs_in_annotations_typeArray()
+// Rewrite constant pool references in the annotation struct portion of
+// an annotations_typeArray. This "structure" is from section 4.8.15 of
+// the 2nd-edition of the VM spec:
+//
+// struct annotation {
+//   u2 type_index;
+//   u2 num_element_value_pairs;
+//   {
+//     u2 element_name_index;
+//     element_value value;
+//   } element_value_pairs[num_element_value_pairs];
+// }
+//
+bool VM_RedefineClasses::rewrite_cp_refs_in_annotation_struct(
+typeArrayHandle annotations_typeArray, int &byte_i_ref, TRAPS) {
+if ((byte_i_ref + 2 + 2) > annotations_typeArray->length()) {
+// not enough room for smallest annotation_struct
+RC_TRACE_WITH_THREAD(0x02000000, THREAD,
+("length() is too small for annotation_struct"));
+return false;
+}
+u2 type_index = rewrite_cp_ref_in_annotation_data(annotations_typeArray,
+byte_i_ref, "mapped old type_index=%d", THREAD);
+u2 num_element_value_pairs = Bytes::get_Java_u2((address)
+annotations_typeArray->byte_at_addr(
+byte_i_ref));
+byte_i_ref += 2;
+RC_TRACE_WITH_THREAD(0x02000000, THREAD,
+("type_index=%d  num_element_value_pairs=%d", type_index,
+num_element_value_pairs));
+int calc_num_element_value_pairs = 0;
+for (; calc_num_element_value_pairs < num_element_value_pairs;
+calc_num_element_value_pairs++) {
+if ((byte_i_ref + 2) > annotations_typeArray->length()) {
+// not enough room for another element_name_index, let alone
+// the rest of another component
+RC_TRACE_WITH_THREAD(0x02000000, THREAD,
+("length() is too small for element_name_index"));
+return false;
+}
+u2 element_name_index = rewrite_cp_ref_in_annotation_data(
+annotations_typeArray, byte_i_ref,
+"mapped old element_name_index=%d", THREAD);
+RC_TRACE_WITH_THREAD(0x02000000, THREAD,
+("element_name_index=%d", element_name_index));
+if (!rewrite_cp_refs_in_element_value(annotations_typeArray,
+byte_i_ref, THREAD)) {
+RC_TRACE_WITH_THREAD(0x02000000, THREAD,
+("bad element_value at %d", calc_num_element_value_pairs));
+// propogate failure back to caller
+return false;
+}
+} // end for each component
+assert(num_element_value_pairs == calc_num_element_value_pairs,
+"sanity check");
+return true;
+} // end rewrite_cp_refs_in_annotation_struct()
+// Rewrite a constant pool reference at the current position in
+// annotations_typeArray if needed. Returns the original constant
+// pool reference if a rewrite was not needed or the new constant
+// pool reference if a rewrite was needed.
+u2 VM_RedefineClasses::rewrite_cp_ref_in_annotation_data(
+typeArrayHandle annotations_typeArray, int &byte_i_ref,
+const char * trace_mesg, TRAPS) {
+address cp_index_addr = (address)
+annotations_typeArray->byte_at_addr(byte_i_ref);
+u2 old_cp_index = Bytes::get_Java_u2(cp_index_addr);
+u2 new_cp_index = find_new_index(old_cp_index);
+if (new_cp_index != 0) {
+RC_TRACE_WITH_THREAD(0x02000000, THREAD, (trace_mesg, old_cp_index));
+Bytes::put_Java_u2(cp_index_addr, new_cp_index);
+old_cp_index = new_cp_index;
+}
+byte_i_ref += 2;
+return old_cp_index;
+}
+// Rewrite constant pool references in the element_value portion of an
+// annotations_typeArray. This "structure" is from section 4.8.15.1 of
+// the 2nd-edition of the VM spec:
+//
+// struct element_value {
+//   u1 tag;
+//   union {
+//     u2 const_value_index;
+//     {
+//       u2 type_name_index;
+//       u2 const_name_index;
+//     } enum_const_value;
+//     u2 class_info_index;
+//     annotation annotation_value;
+//     struct {
+//       u2 num_values;
+//       element_value values[num_values];
+//     } array_value;
+//   } value;
+// }
+//
+bool VM_RedefineClasses::rewrite_cp_refs_in_element_value(
+typeArrayHandle annotations_typeArray, int &byte_i_ref, TRAPS) {
+if ((byte_i_ref + 1) > annotations_typeArray->length()) {
+// not enough room for a tag let alone the rest of an element_value
+RC_TRACE_WITH_THREAD(0x02000000, THREAD,
+("length() is too small for a tag"));
+return false;
+}
+u1 tag = annotations_typeArray->byte_at(byte_i_ref);
+byte_i_ref++;
+RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("tag='%c'", tag));
+switch (tag) {
+// These BaseType tag values are from Table 4.2 in VM spec:
+case 'B':  // byte
+case 'C':  // char
+case 'D':  // double
+case 'F':  // float
+case 'I':  // int
+case 'J':  // long
+case 'S':  // short
+case 'Z':  // boolean
+// The remaining tag values are from Table 4.8 in the 2nd-edition of
+// the VM spec:
+case 's':
+{
+// For the above tag values (including the BaseType values),
+// value.const_value_index is right union field.
+if ((byte_i_ref + 2) > annotations_typeArray->length()) {
+// not enough room for a const_value_index
+RC_TRACE_WITH_THREAD(0x02000000, THREAD,
+("length() is too small for a const_value_index"));
+return false;
+}
+u2 const_value_index = rewrite_cp_ref_in_annotation_data(
+annotations_typeArray, byte_i_ref,
+"mapped old const_value_index=%d", THREAD);
+RC_TRACE_WITH_THREAD(0x02000000, THREAD,
+("const_value_index=%d", const_value_index));
+} break;
+case 'e':
+{
+// for the above tag value, value.enum_const_value is right union field
+if ((byte_i_ref + 4) > annotations_typeArray->length()) {
+// not enough room for a enum_const_value
+RC_TRACE_WITH_THREAD(0x02000000, THREAD,
+("length() is too small for a enum_const_value"));
+return false;
+}
+u2 type_name_index = rewrite_cp_ref_in_annotation_data(
+annotations_typeArray, byte_i_ref,
+"mapped old type_name_index=%d", THREAD);
+u2 const_name_index = rewrite_cp_ref_in_annotation_data(
+annotations_typeArray, byte_i_ref,
+"mapped old const_name_index=%d", THREAD);
+RC_TRACE_WITH_THREAD(0x02000000, THREAD,
+("type_name_index=%d  const_name_index=%d", type_name_index,
+const_name_index));
+} break;
+case 'c':
+{
+// for the above tag value, value.class_info_index is right union field
+if ((byte_i_ref + 2) > annotations_typeArray->length()) {
+// not enough room for a class_info_index
+RC_TRACE_WITH_THREAD(0x02000000, THREAD,
+("length() is too small for a class_info_index"));
+return false;
+}
+u2 class_info_index = rewrite_cp_ref_in_annotation_data(
+annotations_typeArray, byte_i_ref,
+"mapped old class_info_index=%d", THREAD);
+RC_TRACE_WITH_THREAD(0x02000000, THREAD,
+("class_info_index=%d", class_info_index));
+} break;
+case '@':
+// For the above tag value, value.attr_value is the right union
+// field. This is a nested annotation.
+if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray,
+byte_i_ref, THREAD)) {
+// propogate failure back to caller
+return false;
+}
+break;
+case '[':
+{
+if ((byte_i_ref + 2) > annotations_typeArray->length()) {
+// not enough room for a num_values field
+RC_TRACE_WITH_THREAD(0x02000000, THREAD,
+("length() is too small for a num_values field"));
+return false;
+}
+// For the above tag value, value.array_value is the right union
+// field. This is an array of nested element_value.
+u2 num_values = Bytes::get_Java_u2((address)
+annotations_typeArray->byte_at_addr(byte_i_ref));
+byte_i_ref += 2;
+RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("num_values=%d", num_values));
+int calc_num_values = 0;
+for (; calc_num_values < num_values; calc_num_values++) {
+if (!rewrite_cp_refs_in_element_value(
+annotations_typeArray, byte_i_ref, THREAD)) {
+RC_TRACE_WITH_THREAD(0x02000000, THREAD,
+("bad nested element_value at %d", calc_num_values));
+// propogate failure back to caller
+return false;
+}
+}
+assert(num_values == calc_num_values, "sanity check");
+} break;
+default:
+RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("bad tag=0x%x", tag));
+return false;
+} // end decode tag field
+return true;
+} // end rewrite_cp_refs_in_element_value()
+// Rewrite constant pool references in a fields_annotations field.
+bool VM_RedefineClasses::rewrite_cp_refs_in_fields_annotations(
+instanceKlassHandle scratch_class, TRAPS) {
+objArrayHandle fields_annotations(THREAD,
+scratch_class->fields_annotations());
+if (fields_annotations.is_null() || fields_annotations->length() == 0) {
+// no fields_annotations so nothing to do
+return true;
+}
+RC_TRACE_WITH_THREAD(0x02000000, THREAD,
+("fields_annotations length=%d", fields_annotations->length()));
+for (int i = 0; i < fields_annotations->length(); i++) {
+typeArrayHandle field_annotations(THREAD,
+(typeArrayOop)fields_annotations->obj_at(i));
+if (field_annotations.is_null() || field_annotations->length() == 0) {
+// this field does not have any annotations so skip it
+continue;
+}
+int byte_i = 0;  // byte index into field_annotations
+if (!rewrite_cp_refs_in_annotations_typeArray(field_annotations, byte_i,
+THREAD)) {
+RC_TRACE_WITH_THREAD(0x02000000, THREAD,
+("bad field_annotations at %d", i));
+// propogate failure back to caller
+return false;
+}
+}
+return true;
+} // end rewrite_cp_refs_in_fields_annotations()
+// Rewrite constant pool references in a methods_annotations field.
+bool VM_RedefineClasses::rewrite_cp_refs_in_methods_annotations(
+instanceKlassHandle scratch_class, TRAPS) {
+objArrayHandle methods_annotations(THREAD,
+scratch_class->methods_annotations());
+if (methods_annotations.is_null() || methods_annotations->length() == 0) {
+// no methods_annotations so nothing to do
+return true;
+}
+RC_TRACE_WITH_THREAD(0x02000000, THREAD,
+("methods_annotations length=%d", methods_annotations->length()));
+for (int i = 0; i < methods_annotations->length(); i++) {
+typeArrayHandle method_annotations(THREAD,
+(typeArrayOop)methods_annotations->obj_at(i));
+if (method_annotations.is_null() || method_annotations->length() == 0) {
+// this method does not have any annotations so skip it
+continue;
+}
+int byte_i = 0;  // byte index into method_annotations
+if (!rewrite_cp_refs_in_annotations_typeArray(method_annotations, byte_i,
+THREAD)) {
+RC_TRACE_WITH_THREAD(0x02000000, THREAD,
+("bad method_annotations at %d", i));
+// propogate failure back to caller
+return false;
+}
+}
+return true;
+} // end rewrite_cp_refs_in_methods_annotations()
+// Rewrite constant pool references in a methods_parameter_annotations
+// field. This "structure" is adapted from the
+// RuntimeVisibleParameterAnnotations_attribute described in section
+// 4.8.17 of the 2nd-edition of the VM spec:
+//
+// methods_parameter_annotations_typeArray {
+//   u1 num_parameters;
+//   {
+//     u2 num_annotations;
+//     annotation annotations[num_annotations];
+//   } parameter_annotations[num_parameters];
+// }
+//
+bool VM_RedefineClasses::rewrite_cp_refs_in_methods_parameter_annotations(
+instanceKlassHandle scratch_class, TRAPS) {
+objArrayHandle methods_parameter_annotations(THREAD,
+scratch_class->methods_parameter_annotations());
+if (methods_parameter_annotations.is_null()
+|| methods_parameter_annotations->length() == 0) {
+// no methods_parameter_annotations so nothing to do
+return true;
+}
+RC_TRACE_WITH_THREAD(0x02000000, THREAD,
+("methods_parameter_annotations length=%d",
+methods_parameter_annotations->length()));
+for (int i = 0; i < methods_parameter_annotations->length(); i++) {
+typeArrayHandle method_parameter_annotations(THREAD,
+(typeArrayOop)methods_parameter_annotations->obj_at(i));
+if (method_parameter_annotations.is_null()
+|| method_parameter_annotations->length() == 0) {
+// this method does not have any parameter annotations so skip it
+continue;
+}
+if (method_parameter_annotations->length() < 1) {
+// not enough room for a num_parameters field
+RC_TRACE_WITH_THREAD(0x02000000, THREAD,
+("length() is too small for a num_parameters field at %d", i));
+return false;
+}
+int byte_i = 0;  // byte index into method_parameter_annotations
+u1 num_parameters = method_parameter_annotations->byte_at(byte_i);
+byte_i++;
+RC_TRACE_WITH_THREAD(0x02000000, THREAD,
+("num_parameters=%d", num_parameters));
+int calc_num_parameters = 0;
+for (; calc_num_parameters < num_parameters; calc_num_parameters++) {
+if (!rewrite_cp_refs_in_annotations_typeArray(
+method_parameter_annotations, byte_i, THREAD)) {
+RC_TRACE_WITH_THREAD(0x02000000, THREAD,
+("bad method_parameter_annotations at %d", calc_num_parameters));
+// propogate failure back to caller
+return false;
+}
+}
+assert(num_parameters == calc_num_parameters, "sanity check");
+}
+return true;
+} // end rewrite_cp_refs_in_methods_parameter_annotations()
+// Rewrite constant pool references in a methods_default_annotations
+// field. This "structure" is adapted from the AnnotationDefault_attribute
+// that is described in section 4.8.19 of the 2nd-edition of the VM spec:
+//
+// methods_default_annotations_typeArray {
+//   element_value default_value;
+// }
+//
+bool VM_RedefineClasses::rewrite_cp_refs_in_methods_default_annotations(
+instanceKlassHandle scratch_class, TRAPS) {
+objArrayHandle methods_default_annotations(THREAD,
+scratch_class->methods_default_annotations());
+if (methods_default_annotations.is_null()
+|| methods_default_annotations->length() == 0) {
+// no methods_default_annotations so nothing to do
+return true;
+}
+RC_TRACE_WITH_THREAD(0x02000000, THREAD,
+("methods_default_annotations length=%d",
+methods_default_annotations->length()));
+for (int i = 0; i < methods_default_annotations->length(); i++) {
+typeArrayHandle method_default_annotations(THREAD,
+(typeArrayOop)methods_default_annotations->obj_at(i));
+if (method_default_annotations.is_null()
+|| method_default_annotations->length() == 0) {
+// this method does not have any default annotations so skip it
+continue;
+}
+int byte_i = 0;  // byte index into method_default_annotations
+if (!rewrite_cp_refs_in_element_value(
+method_default_annotations, byte_i, THREAD)) {
+RC_TRACE_WITH_THREAD(0x02000000, THREAD,
+("bad default element_value at %d", i));
+// propogate failure back to caller
+return false;
+}
+}
+return true;
+} // end rewrite_cp_refs_in_methods_default_annotations()
+// Rewrite constant pool references in the method's stackmap table.
+// These "structures" are adapted from the StackMapTable_attribute that
+// is described in section 4.8.4 of the 6.0 version of the VM spec
+// (dated 2005.10.26):
+// file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf
+//
+// stack_map {
+//   u2 number_of_entries;
+//   stack_map_frame entries[number_of_entries];
+// }
+//
+void VM_RedefineClasses::rewrite_cp_refs_in_stack_map_table(
+methodHandle method, TRAPS) {
+if (!method->has_stackmap_table()) {
+return;
+}
+typeArrayOop stackmap_data = method->stackmap_data();
+address stackmap_p = (address)stackmap_data->byte_at_addr(0);
+address stackmap_end = stackmap_p + stackmap_data->length();
+assert(stackmap_p + 2 <= stackmap_end, "no room for number_of_entries");
+u2 number_of_entries = Bytes::get_Java_u2(stackmap_p);
+stackmap_p += 2;
+RC_TRACE_WITH_THREAD(0x04000000, THREAD,
+("number_of_entries=%u", number_of_entries));
+// walk through each stack_map_frame
+u2 calc_number_of_entries = 0;
+for (; calc_number_of_entries < number_of_entries; calc_number_of_entries++) {
+// The stack_map_frame structure is a u1 frame_type followed by
+// 0 or more bytes of data:
+//
+// union stack_map_frame {
+//   same_frame;
+//   same_locals_1_stack_item_frame;
+//   same_locals_1_stack_item_frame_extended;
+//   chop_frame;
+//   same_frame_extended;
+//   append_frame;
+//   full_frame;
+// }
+assert(stackmap_p + 1 <= stackmap_end, "no room for frame_type");
+// The Linux compiler does not like frame_type to be u1 or u2. It
+// issues the following warning for the first if-statement below:
+//
+// "warning: comparison is always true due to limited range of data type"
+//
+u4 frame_type = *stackmap_p;
+stackmap_p++;
+// same_frame {
+//   u1 frame_type = SAME; /* 0-63 */
+// }
+if (frame_type >= 0 && frame_type <= 63) {
+// nothing more to do for same_frame
+}
+// same_locals_1_stack_item_frame {
+//   u1 frame_type = SAME_LOCALS_1_STACK_ITEM; /* 64-127 */
+//   verification_type_info stack[1];
+// }
+else if (frame_type >= 64 && frame_type <= 127) {
+rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
+calc_number_of_entries, frame_type, THREAD);
+}
+// reserved for future use
+else if (frame_type >= 128 && frame_type <= 246) {
+// nothing more to do for reserved frame_types
+}
+// same_locals_1_stack_item_frame_extended {
+//   u1 frame_type = SAME_LOCALS_1_STACK_ITEM_EXTENDED; /* 247 */
+//   u2 offset_delta;
+//   verification_type_info stack[1];
+// }
+else if (frame_type == 247) {
+stackmap_p += 2;
+rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
+calc_number_of_entries, frame_type, THREAD);
+}
+// chop_frame {
+//   u1 frame_type = CHOP; /* 248-250 */
+//   u2 offset_delta;
+// }
+else if (frame_type >= 248 && frame_type <= 250) {
+stackmap_p += 2;
+}
+// same_frame_extended {
+//   u1 frame_type = SAME_FRAME_EXTENDED; /* 251*/
+//   u2 offset_delta;
+// }
+else if (frame_type == 251) {
+stackmap_p += 2;
+}
+// append_frame {
+//   u1 frame_type = APPEND; /* 252-254 */
+//   u2 offset_delta;
+//   verification_type_info locals[frame_type - 251];
+// }
+else if (frame_type >= 252 && frame_type <= 254) {
+assert(stackmap_p + 2 <= stackmap_end,
+"no room for offset_delta");
+stackmap_p += 2;
+u1 len = frame_type - 251;
+for (u1 i = 0; i < len; i++) {
+rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
+calc_number_of_entries, frame_type, THREAD);
+}
+}
+// full_frame {
+//   u1 frame_type = FULL_FRAME; /* 255 */
+//   u2 offset_delta;
+//   u2 number_of_locals;
+//   verification_type_info locals[number_of_locals];
+//   u2 number_of_stack_items;
+//   verification_type_info stack[number_of_stack_items];
+// }
+else if (frame_type == 255) {
+assert(stackmap_p + 2 + 2 <= stackmap_end,
+"no room for smallest full_frame");
+stackmap_p += 2;
+u2 number_of_locals = Bytes::get_Java_u2(stackmap_p);
+stackmap_p += 2;
+for (u2 locals_i = 0; locals_i < number_of_locals; locals_i++) {
+rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
+calc_number_of_entries, frame_type, THREAD);
+}
+// Use the largest size for the number_of_stack_items, but only get
+// the right number of bytes.
+u2 number_of_stack_items = Bytes::get_Java_u2(stackmap_p);
+stackmap_p += 2;
+for (u2 stack_i = 0; stack_i < number_of_stack_items; stack_i++) {
+rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
+calc_number_of_entries, frame_type, THREAD);
+}
+}
+} // end while there is a stack_map_frame
+assert(number_of_entries == calc_number_of_entries, "sanity check");
+} // end rewrite_cp_refs_in_stack_map_table()
+// Rewrite constant pool references in the verification type info
+// portion of the method's stackmap table. These "structures" are
+// adapted from the StackMapTable_attribute that is described in
+// section 4.8.4 of the 6.0 version of the VM spec (dated 2005.10.26):
+// file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf
+//
+// The verification_type_info structure is a u1 tag followed by 0 or
+// more bytes of data:
+//
+// union verification_type_info {
+//   Top_variable_info;
+//   Integer_variable_info;
+//   Float_variable_info;
+//   Long_variable_info;
+//   Double_variable_info;
+//   Null_variable_info;
+//   UninitializedThis_variable_info;
+//   Object_variable_info;
+//   Uninitialized_variable_info;
+// }
+//
+void VM_RedefineClasses::rewrite_cp_refs_in_verification_type_info(
+address& stackmap_p_ref, address stackmap_end, u2 frame_i,
+u1 frame_type, TRAPS) {
+assert(stackmap_p_ref + 1 <= stackmap_end, "no room for tag");
+u1 tag = *stackmap_p_ref;
+stackmap_p_ref++;
+switch (tag) {
+// Top_variable_info {
+//   u1 tag = ITEM_Top; /* 0 */
+// }
+// verificationType.hpp has zero as ITEM_Bogus instead of ITEM_Top
+case 0:  // fall through
+// Integer_variable_info {
+//   u1 tag = ITEM_Integer; /* 1 */
+// }
+case ITEM_Integer:  // fall through
+// Float_variable_info {
+//   u1 tag = ITEM_Float; /* 2 */
+// }
+case ITEM_Float:  // fall through
+// Double_variable_info {
+//   u1 tag = ITEM_Double; /* 3 */
+// }
+case ITEM_Double:  // fall through
+// Long_variable_info {
+//   u1 tag = ITEM_Long; /* 4 */
+// }
+case ITEM_Long:  // fall through
+// Null_variable_info {
+//   u1 tag = ITEM_Null; /* 5 */
+// }
+case ITEM_Null:  // fall through
+// UninitializedThis_variable_info {
+//   u1 tag = ITEM_UninitializedThis; /* 6 */
+// }
+case ITEM_UninitializedThis:
+// nothing more to do for the above tag types
+break;
+// Object_variable_info {
+//   u1 tag = ITEM_Object; /* 7 */
+//   u2 cpool_index;
+// }
+case ITEM_Object:
+{
+assert(stackmap_p_ref + 2 <= stackmap_end, "no room for cpool_index");
+u2 cpool_index = Bytes::get_Java_u2(stackmap_p_ref);
+u2 new_cp_index = find_new_index(cpool_index);
+if (new_cp_index != 0) {
+RC_TRACE_WITH_THREAD(0x04000000, THREAD,
+("mapped old cpool_index=%d", cpool_index));
+Bytes::put_Java_u2(stackmap_p_ref, new_cp_index);
+cpool_index = new_cp_index;
+}
+stackmap_p_ref += 2;
+RC_TRACE_WITH_THREAD(0x04000000, THREAD,
+("frame_i=%u, frame_type=%u, cpool_index=%d", frame_i,
+frame_type, cpool_index));
+} break;
+// Uninitialized_variable_info {
+//   u1 tag = ITEM_Uninitialized; /* 8 */
+//   u2 offset;
+// }
+case ITEM_Uninitialized:
+assert(stackmap_p_ref + 2 <= stackmap_end, "no room for offset");
+stackmap_p_ref += 2;
+break;
+default:
+RC_TRACE_WITH_THREAD(0x04000000, THREAD,
+("frame_i=%u, frame_type=%u, bad tag=0x%x", frame_i, frame_type, tag));
+ShouldNotReachHere();
+break;
+} // end switch (tag)
+} // end rewrite_cp_refs_in_verification_type_info()
+// Change the constant pool associated with klass scratch_class to
+// scratch_cp. If shrink is true, then scratch_cp_length elements
+// are copied from scratch_cp to a smaller constant pool and the
+// smaller constant pool is associated with scratch_class.
+void VM_RedefineClasses::set_new_constant_pool(
+instanceKlassHandle scratch_class, constantPoolHandle scratch_cp,
+int scratch_cp_length, bool shrink, TRAPS) {
+assert(!shrink || scratch_cp->length() >= scratch_cp_length, "sanity check");
+if (shrink) {
+// scratch_cp is a merged constant pool and has enough space for a
+// worst case merge situation. We want to associate the minimum
+// sized constant pool with the klass to save space.
+constantPoolHandle smaller_cp(THREAD,
+oopFactory::new_constantPool(scratch_cp_length, THREAD));
+// preserve orig_length() value in the smaller copy
+int orig_length = scratch_cp->orig_length();
+assert(orig_length != 0, "sanity check");
+smaller_cp->set_orig_length(orig_length);
+scratch_cp->copy_cp_to(1, scratch_cp_length - 1, smaller_cp, 1, THREAD);
+scratch_cp = smaller_cp;
+}
+// attach new constant pool to klass
+scratch_cp->set_pool_holder(scratch_class());
+// attach klass to new constant pool
+scratch_class->set_constants(scratch_cp());
+int i;  // for portability
+// update each field in klass to use new constant pool indices as needed
+typeArrayHandle fields(THREAD, scratch_class->fields());
+int n_fields = fields->length();
+for (i = 0; i < n_fields; i += instanceKlass::next_offset) {
+jshort cur_index = fields->short_at(i + instanceKlass::name_index_offset);
+jshort new_index = find_new_index(cur_index);
+if (new_index != 0) {
+RC_TRACE_WITH_THREAD(0x00080000, THREAD,
+("field-name_index change: %d to %d", cur_index, new_index));
+fields->short_at_put(i + instanceKlass::name_index_offset, new_index);
+}
+cur_index = fields->short_at(i + instanceKlass::signature_index_offset);
+new_index = find_new_index(cur_index);
+if (new_index != 0) {
+RC_TRACE_WITH_THREAD(0x00080000, THREAD,
+("field-signature_index change: %d to %d", cur_index, new_index));
+fields->short_at_put(i + instanceKlass::signature_index_offset,
+new_index);
+}
+cur_index = fields->short_at(i + instanceKlass::initval_index_offset);
+new_index = find_new_index(cur_index);
+if (new_index != 0) {
+RC_TRACE_WITH_THREAD(0x00080000, THREAD,
+("field-initval_index change: %d to %d", cur_index, new_index));
+fields->short_at_put(i + instanceKlass::initval_index_offset, new_index);
+}
+cur_index = fields->short_at(i + instanceKlass::generic_signature_offset);
+new_index = find_new_index(cur_index);
+if (new_index != 0) {
+RC_TRACE_WITH_THREAD(0x00080000, THREAD,
+("field-generic_signature change: %d to %d", cur_index, new_index));
+fields->short_at_put(i + instanceKlass::generic_signature_offset,
+new_index);
+}
+} // end for each field
+// Update constant pool indices in the inner classes info to use
+// new constant indices as needed. The inner classes info is a
+// quadruple:
+// (inner_class_info, outer_class_info, inner_name, inner_access_flags)
+typeArrayOop inner_class_list = scratch_class->inner_classes();
+int icl_length = (inner_class_list == NULL) ? 0 : inner_class_list->length();
+if (icl_length > 0) {
+typeArrayHandle inner_class_list_h(THREAD, inner_class_list);
+for (int i = 0; i < icl_length;
+i += instanceKlass::inner_class_next_offset) {
+int cur_index = inner_class_list_h->ushort_at(i
++ instanceKlass::inner_class_inner_class_info_offset);
+if (cur_index == 0) {
+continue;  // JVM spec. allows null inner class refs so skip it
+}
+int new_index = find_new_index(cur_index);
+if (new_index != 0) {
+RC_TRACE_WITH_THREAD(0x00080000, THREAD,
+("inner_class_info change: %d to %d", cur_index, new_index));
+inner_class_list_h->ushort_at_put(i
++ instanceKlass::inner_class_inner_class_info_offset, new_index);
+}
+cur_index = inner_class_list_h->ushort_at(i
++ instanceKlass::inner_class_outer_class_info_offset);
+new_index = find_new_index(cur_index);
+if (new_index != 0) {
+RC_TRACE_WITH_THREAD(0x00080000, THREAD,
+("outer_class_info change: %d to %d", cur_index, new_index));
+inner_class_list_h->ushort_at_put(i
++ instanceKlass::inner_class_outer_class_info_offset, new_index);
+}
+cur_index = inner_class_list_h->ushort_at(i
++ instanceKlass::inner_class_inner_name_offset);
+new_index = find_new_index(cur_index);
+if (new_index != 0) {
+RC_TRACE_WITH_THREAD(0x00080000, THREAD,
+("inner_name change: %d to %d", cur_index, new_index));
+inner_class_list_h->ushort_at_put(i
++ instanceKlass::inner_class_inner_name_offset, new_index);
+}
+} // end for each inner class
+} // end if we have inner classes
+// Attach each method in klass to the new constant pool and update
+// to use new constant pool indices as needed:
+objArrayHandle methods(THREAD, scratch_class->methods());
+for (i = methods->length() - 1; i >= 0; i--) {
+methodHandle method(THREAD, (methodOop)methods->obj_at(i));
+method->set_constants(scratch_cp());
+int new_index = find_new_index(method->name_index());
+if (new_index != 0) {
+RC_TRACE_WITH_THREAD(0x00080000, THREAD,
+("method-name_index change: %d to %d", method->name_index(),
+new_index));
+method->set_name_index(new_index);
+}
+new_index = find_new_index(method->signature_index());
+if (new_index != 0) {
+RC_TRACE_WITH_THREAD(0x00080000, THREAD,
+("method-signature_index change: %d to %d",
+method->signature_index(), new_index));
+method->set_signature_index(new_index);
+}
+new_index = find_new_index(method->generic_signature_index());
+if (new_index != 0) {
+RC_TRACE_WITH_THREAD(0x00080000, THREAD,
+("method-generic_signature_index change: %d to %d",
+method->generic_signature_index(), new_index));
+method->set_generic_signature_index(new_index);
+}
+// Update constant pool indices in the method's checked exception
+// table to use new constant indices as needed.
+int cext_length = method->checked_exceptions_length();
+if (cext_length > 0) {
+CheckedExceptionElement * cext_table =
+method->checked_exceptions_start();
+for (int j = 0; j < cext_length; j++) {
+int cur_index = cext_table[j].class_cp_index;
+int new_index = find_new_index(cur_index);
+if (new_index != 0) {
+RC_TRACE_WITH_THREAD(0x00080000, THREAD,
+("cext-class_cp_index change: %d to %d", cur_index, new_index));
+cext_table[j].class_cp_index = (u2)new_index;
+}
+} // end for each checked exception table entry
+} // end if there are checked exception table entries
+// Update each catch type index in the method's exception table
+// to use new constant pool indices as needed. The exception table
+// holds quadruple entries of the form:
+//   (beg_bci, end_bci, handler_bci, klass_index)
+const int beg_bci_offset     = 0;
+const int end_bci_offset     = 1;
+const int handler_bci_offset = 2;
+const int klass_index_offset = 3;
+const int entry_size         = 4;
+typeArrayHandle ex_table (THREAD, method->exception_table());
+int ext_length = ex_table->length();
+assert(ext_length % entry_size == 0, "exception table format has changed");
+for (int j = 0; j < ext_length; j += entry_size) {
+int cur_index = ex_table->int_at(j + klass_index_offset);
+int new_index = find_new_index(cur_index);
+if (new_index != 0) {
+RC_TRACE_WITH_THREAD(0x00080000, THREAD,
+("ext-klass_index change: %d to %d", cur_index, new_index));
+ex_table->int_at_put(j + klass_index_offset, new_index);
+}
+} // end for each exception table entry
+// Update constant pool indices in the method's local variable
+// table to use new constant indices as needed. The local variable
+// table hold sextuple entries of the form:
+// (start_pc, length, name_index, descriptor_index, signature_index, slot)
+int lvt_length = method->localvariable_table_length();
+if (lvt_length > 0) {
+LocalVariableTableElement * lv_table =
+method->localvariable_table_start();
+for (int j = 0; j < lvt_length; j++) {
+int cur_index = lv_table[j].name_cp_index;
+int new_index = find_new_index(cur_index);
+if (new_index != 0) {
+RC_TRACE_WITH_THREAD(0x00080000, THREAD,
+("lvt-name_cp_index change: %d to %d", cur_index, new_index));
+lv_table[j].name_cp_index = (u2)new_index;
+}
+cur_index = lv_table[j].descriptor_cp_index;
+new_index = find_new_index(cur_index);
+if (new_index != 0) {
+RC_TRACE_WITH_THREAD(0x00080000, THREAD,
+("lvt-descriptor_cp_index change: %d to %d", cur_index,
+new_index));
+lv_table[j].descriptor_cp_index = (u2)new_index;
+}
+cur_index = lv_table[j].signature_cp_index;
+new_index = find_new_index(cur_index);
+if (new_index != 0) {
+RC_TRACE_WITH_THREAD(0x00080000, THREAD,
+("lvt-signature_cp_index change: %d to %d", cur_index, new_index));
+lv_table[j].signature_cp_index = (u2)new_index;
+}
+} // end for each local variable table entry
+} // end if there are local variable table entries
+rewrite_cp_refs_in_stack_map_table(method, THREAD);
+} // end for each method
+} // end set_new_constant_pool()
+// Unevolving classes may point to methods of the_class directly
+// from their constant pool caches, itables, and/or vtables. We
+// use the SystemDictionary::classes_do() facility and this helper
+// to fix up these pointers.
+//
+// Note: We currently don't support updating the vtable in
+// arrayKlassOops. See Open Issues in jvmtiRedefineClasses.hpp.
+void VM_RedefineClasses::adjust_cpool_cache_and_vtable(klassOop k_oop,
+oop initiating_loader, TRAPS) {
+Klass *k = k_oop->klass_part();
+if (k->oop_is_instance()) {
+HandleMark hm(THREAD);
+instanceKlass *ik = (instanceKlass *) k;
+// HotSpot specific optimization! HotSpot does not currently
+// support delegation from the bootstrap class loader to a
+// user-defined class loader. This means that if the bootstrap
+// class loader is the initiating class loader, then it will also
+// be the defining class loader. This also means that classes
+// loaded by the bootstrap class loader cannot refer to classes
+// loaded by a user-defined class loader. Note: a user-defined
+// class loader can delegate to the bootstrap class loader.
+//
+// If the current class being redefined has a user-defined class
+// loader as its defining class loader, then we can skip all
+// classes loaded by the bootstrap class loader.
+bool is_user_defined =
+instanceKlass::cast(_the_class_oop)->class_loader() != NULL;
+if (is_user_defined && ik->class_loader() == NULL) {
+return;
+}
+// This is a very busy routine. We don't want too much tracing
+// printed out.
+bool trace_name_printed = false;
+// Very noisy: only enable this call if you are trying to determine
+// that a specific class gets found by this routine.
+// RC_TRACE macro has an embedded ResourceMark
+// RC_TRACE_WITH_THREAD(0x00100000, THREAD,
+//   ("adjust check: name=%s", ik->external_name()));
+// trace_name_printed = true;
+// Fix the vtable embedded in the_class and subclasses of the_class,
+// if one exists. We discard scratch_class and we don't keep an
+// instanceKlass around to hold obsolete methods so we don't have
+// any other instanceKlass embedded vtables to update. The vtable
+// holds the methodOops for virtual (but not final) methods.
+if (ik->vtable_length() > 0 && ik->is_subtype_of(_the_class_oop)) {
+// ik->vtable() creates a wrapper object; rm cleans it up
+ResourceMark rm(THREAD);
+ik->vtable()->adjust_method_entries(_matching_old_methods,
+_matching_new_methods,
+_matching_methods_length,
+&trace_name_printed);
+}
+// If the current class has an itable and we are either redefining an
+// interface or if the current class is a subclass of the_class, then
+// we potentially have to fix the itable. If we are redefining an
+// interface, then we have to call adjust_method_entries() for
+// every instanceKlass that has an itable since there isn't a
+// subclass relationship between an interface and an instanceKlass.
+if (ik->itable_length() > 0 && (Klass::cast(_the_class_oop)->is_interface()
+|| ik->is_subclass_of(_the_class_oop))) {
+// ik->itable() creates a wrapper object; rm cleans it up
+ResourceMark rm(THREAD);
+ik->itable()->adjust_method_entries(_matching_old_methods,
+_matching_new_methods,
+_matching_methods_length,
+&trace_name_printed);
+}
+// The constant pools in other classes (other_cp) can refer to
+// methods in the_class. We have to update method information in
+// other_cp's cache. If other_cp has a previous version, then we
+// have to repeat the process for each previous version. The
+// constant pool cache holds the methodOops for non-virtual
+// methods and for virtual, final methods.
+//
+// Special case: if the current class is the_class, then new_cp
+// has already been attached to the_class and old_cp has already
+// been added as a previous version. The new_cp doesn't have any
+// cached references to old methods so it doesn't need to be
+// updated. We can simply start with the previous version(s) in
+// that case.
+constantPoolHandle other_cp;
+constantPoolCacheOop cp_cache;
+if (k_oop != _the_class_oop) {
+// this klass' constant pool cache may need adjustment
+other_cp = constantPoolHandle(ik->constants());
+cp_cache = other_cp->cache();
+if (cp_cache != NULL) {
+cp_cache->adjust_method_entries(_matching_old_methods,
+_matching_new_methods,
+_matching_methods_length,
+&trace_name_printed);
+}
+}
+{
+ResourceMark rm(THREAD);
+// PreviousVersionInfo objects returned via PreviousVersionWalker
+// contain a GrowableArray of handles. We have to clean up the
+// GrowableArray _after_ the PreviousVersionWalker destructor
+// has destroyed the handles.
+{
+// the previous versions' constant pool caches may need adjustment
+PreviousVersionWalker pvw(ik);
+for (PreviousVersionInfo * pv_info = pvw.next_previous_version();
+pv_info != NULL; pv_info = pvw.next_previous_version()) {
+other_cp = pv_info->prev_constant_pool_handle();
+cp_cache = other_cp->cache();
+if (cp_cache != NULL) {
+cp_cache->adjust_method_entries(_matching_old_methods,
+_matching_new_methods,
+_matching_methods_length,
+&trace_name_printed);
+}
+}
+} // pvw is cleaned up
+} // rm is cleaned up
+}
+}
+void VM_RedefineClasses::update_jmethod_ids() {
+for (int j = 0; j < _matching_methods_length; ++j) {
+methodOop old_method = _matching_old_methods[j];
+jmethodID jmid = old_method->find_jmethod_id_or_null();
+if (jmid != NULL) {
+// There is a jmethodID, change it to point to the new method
+methodHandle new_method_h(_matching_new_methods[j]);
+JNIHandles::change_method_associated_with_jmethod_id(jmid, new_method_h);
+assert(JNIHandles::resolve_jmethod_id(jmid) == _matching_new_methods[j],
+"should be replaced");
+}
+}
+}
+void VM_RedefineClasses::check_methods_and_mark_as_obsolete(
+BitMap *emcp_methods, int * emcp_method_count_p) {
+*emcp_method_count_p = 0;
+int obsolete_count = 0;
+int old_index = 0;
+for (int j = 0; j < _matching_methods_length; ++j, ++old_index) {
+methodOop old_method = _matching_old_methods[j];
+methodOop new_method = _matching_new_methods[j];
+methodOop old_array_method;
+// Maintain an old_index into the _old_methods array by skipping
+// deleted methods
+while ((old_array_method = (methodOop) _old_methods->obj_at(old_index))
+!= old_method) {
+++old_index;
+}
+if (MethodComparator::methods_EMCP(old_method, new_method)) {
+// The EMCP definition from JSR-163 requires the bytecodes to be
+// the same with the exception of constant pool indices which may
+// differ. However, the constants referred to by those indices
+// must be the same.
+//
+// We use methods_EMCP() for comparison since constant pool
+// merging can remove duplicate constant pool entries that were
+// present in the old method and removed from the rewritten new
+// method. A faster binary comparison function would consider the
+// old and new methods to be different when they are actually
+// EMCP.
+//
+// The old and new methods are EMCP and you would think that we
+// could get rid of one of them here and now and save some space.
+// However, the concept of EMCP only considers the bytecodes and
+// the constant pool entries in the comparison. Other things,
+// e.g., the line number table (LNT) or the local variable table
+// (LVT) don't count in the comparison. So the new (and EMCP)
+// method can have a new LNT that we need so we can't just
+// overwrite the new method with the old method.
+//
+// When this routine is called, we have already attached the new
+// methods to the_class so the old methods are effectively
+// overwritten. However, if an old method is still executing,
+// then the old method cannot be collected until sometime after
+// the old method call has returned. So the overwriting of old
+// methods by new methods will save us space except for those
+// (hopefully few) old methods that are still executing.
+//
+// A method refers to a constMethodOop and this presents another
+// possible avenue to space savings. The constMethodOop in the
+// new method contains possibly new attributes (LNT, LVT, etc).
+// At first glance, it seems possible to save space by replacing
+// the constMethodOop in the old method with the constMethodOop
+// from the new method. The old and new methods would share the
+// same constMethodOop and we would save the space occupied by
+// the old constMethodOop. However, the constMethodOop contains
+// a back reference to the containing method. Sharing the
+// constMethodOop between two methods could lead to confusion in
+// the code that uses the back reference. This would lead to
+// brittle code that could be broken in non-obvious ways now or
+// in the future.
+//
+// Another possibility is to copy the constMethodOop from the new
+// method to the old method and then overwrite the new method with
+// the old method. Since the constMethodOop contains the bytecodes
+// for the method embedded in the oop, this option would change
+// the bytecodes out from under any threads executing the old
+// method and make the thread's bcp invalid. Since EMCP requires
+// that the bytecodes be the same modulo constant pool indices, it
+// is straight forward to compute the correct new bcp in the new
+// constMethodOop from the old bcp in the old constMethodOop. The
+// time consuming part would be searching all the frames in all
+// of the threads to find all of the calls to the old method.
+//
+// It looks like we will have to live with the limited savings
+// that we get from effectively overwriting the old methods
+// when the new methods are attached to the_class.
+// track which methods are EMCP for add_previous_version() call
+emcp_methods->set_bit(old_index);
+(*emcp_method_count_p)++;
+// An EMCP method is _not_ obsolete. An obsolete method has a
+// different jmethodID than the current method. An EMCP method
+// has the same jmethodID as the current method. Having the
+// same jmethodID for all EMCP versions of a method allows for
+// a consistent view of the EMCP methods regardless of which
+// EMCP method you happen to have in hand. For example, a
+// breakpoint set in one EMCP method will work for all EMCP
+// versions of the method including the current one.
+} else {
+// mark obsolete methods as such
+old_method->set_is_obsolete();
+obsolete_count++;
+// obsolete methods need a unique idnum
+u2 num = instanceKlass::cast(_the_class_oop)->next_method_idnum();
+if (num != constMethodOopDesc::UNSET_IDNUM) {
+//      u2 old_num = old_method->method_idnum();
+old_method->set_method_idnum(num);
+// TO DO: attach obsolete annotations to obsolete method's new idnum
+}
+// With tracing we try not to "yack" too much. The position of
+// this trace assumes there are fewer obsolete methods than
+// EMCP methods.
+RC_TRACE(0x00000100, ("mark %s(%s) as obsolete",
+old_method->name()->as_C_string(),
+old_method->signature()->as_C_string()));
+}
+old_method->set_is_old();
+}
+for (int i = 0; i < _deleted_methods_length; ++i) {
+methodOop old_method = _deleted_methods[i];
+assert(old_method->vtable_index() < 0,
+"cannot delete methods with vtable entries");;
+// Mark all deleted methods as old and obsolete
+old_method->set_is_old();
+old_method->set_is_obsolete();
+++obsolete_count;
+// With tracing we try not to "yack" too much. The position of
+// this trace assumes there are fewer obsolete methods than
+// EMCP methods.
+RC_TRACE(0x00000100, ("mark deleted %s(%s) as obsolete",
+old_method->name()->as_C_string(),
+old_method->signature()->as_C_string()));
+}
+assert((*emcp_method_count_p + obsolete_count) == _old_methods->length(),
+"sanity check");
+RC_TRACE(0x00000100, ("EMCP_cnt=%d, obsolete_cnt=%d", *emcp_method_count_p,
+obsolete_count));
+}
+// This internal class transfers the native function registration from old methods
+// to new methods.  It is designed to handle both the simple case of unchanged
+// native methods and the complex cases of native method prefixes being added and/or
+// removed.
+// It expects only to be used during the VM_RedefineClasses op (a safepoint).
+//
+// This class is used after the new methods have been installed in "the_class".
+//
+// So, for example, the following must be handled.  Where 'm' is a method and
+// a number followed by an underscore is a prefix.
+//
+//                                      Old Name    New Name
+// Simple transfer to new method        m       ->  m
+// Add prefix                           m       ->  1_m
+// Remove prefix                        1_m     ->  m
+// Simultaneous add of prefixes         m       ->  3_2_1_m
+// Simultaneous removal of prefixes     3_2_1_m ->  m
+// Simultaneous add and remove          1_m     ->  2_m
+// Same, caused by prefix removal only  3_2_1_m ->  3_2_m
+//
+class TransferNativeFunctionRegistration {
+private:
+instanceKlassHandle the_class;
+int prefix_count;
+char** prefixes;
+// Recursively search the binary tree of possibly prefixed method names.
+// Iteration could be used if all agents were well behaved. Full tree walk is
+// more resilent to agents not cleaning up intermediate methods.
+// Branch at each depth in the binary tree is:
+//    (1) without the prefix.
+//    (2) with the prefix.
+// where 'prefix' is the prefix at that 'depth' (first prefix, second prefix,...)
+methodOop search_prefix_name_space(int depth, char* name_str, size_t name_len,
+symbolOop signature) {
+symbolOop name_symbol = SymbolTable::probe(name_str, (int)name_len);
+if (name_symbol != NULL) {
+methodOop method = Klass::cast(the_class())->lookup_method(name_symbol, signature);
+if (method != NULL) {
+// Even if prefixed, intermediate methods must exist.
+if (method->is_native()) {
+// Wahoo, we found a (possibly prefixed) version of the method, return it.
+return method;
+}
+if (depth < prefix_count) {
+// Try applying further prefixes (other than this one).
+method = search_prefix_name_space(depth+1, name_str, name_len, signature);
+if (method != NULL) {
+return method; // found
+}
+// Try adding this prefix to the method name and see if it matches
+// another method name.
+char* prefix = prefixes[depth];
+size_t prefix_len = strlen(prefix);
+size_t trial_len = name_len + prefix_len;
+char* trial_name_str = NEW_RESOURCE_ARRAY(char, trial_len + 1);
+strcpy(trial_name_str, prefix);
+strcat(trial_name_str, name_str);
+method = search_prefix_name_space(depth+1, trial_name_str, trial_len,
+signature);
+if (method != NULL) {
+// If found along this branch, it was prefixed, mark as such
+method->set_is_prefixed_native();
+return method; // found
+}
+}
+}
+}
+return NULL;  // This whole branch bore nothing
+}
+// Return the method name with old prefixes stripped away.
+char* method_name_without_prefixes(methodOop method) {
+symbolOop name = method->name();
+char* name_str = name->as_utf8();
+// Old prefixing may be defunct, strip prefixes, if any.
+for (int i = prefix_count-1; i >= 0; i--) {
+char* prefix = prefixes[i];
+size_t prefix_len = strlen(prefix);
+if (strncmp(prefix, name_str, prefix_len) == 0) {
+name_str += prefix_len;
+}
+}
+return name_str;
+}
+// Strip any prefixes off the old native method, then try to find a
+// (possibly prefixed) new native that matches it.
+methodOop strip_and_search_for_new_native(methodOop method) {
+ResourceMark rm;
+char* name_str = method_name_without_prefixes(method);
+return search_prefix_name_space(0, name_str, strlen(name_str),
+method->signature());
+}
+public:
+// Construct a native method transfer processor for this class.
+TransferNativeFunctionRegistration(instanceKlassHandle _the_class) {
+assert(SafepointSynchronize::is_at_safepoint(), "sanity check");
+the_class = _the_class;
+prefixes = JvmtiExport::get_all_native_method_prefixes(&prefix_count);
+}
+// Attempt to transfer any of the old or deleted methods that are native
+void transfer_registrations(methodOop* old_methods, int methods_length) {
+for (int j = 0; j < methods_length; j++) {
+methodOop old_method = old_methods[j];
+if (old_method->is_native() && old_method->has_native_function()) {
+methodOop new_method = strip_and_search_for_new_native(old_method);
+if (new_method != NULL) {
+// Actually set the native function in the new method.
+// Redefine does not send events (except CFLH), certainly not this
+// behind the scenes re-registration.
+new_method->set_native_function(old_method->native_function(),
+!methodOopDesc::native_bind_event_is_interesting);
+}
+}
+}
+}
+};
+// Don't lose the association between a native method and its JNI function.
+void VM_RedefineClasses::transfer_old_native_function_registrations(instanceKlassHandle the_class) {
+TransferNativeFunctionRegistration transfer(the_class);
+transfer.transfer_registrations(_deleted_methods, _deleted_methods_length);
+transfer.transfer_registrations(_matching_old_methods, _matching_methods_length);
+}
+// Deoptimize all compiled code that depends on this class.
+//
+// If the can_redefine_classes capability is obtained in the onload
+// phase then the compiler has recorded all dependencies from startup.
+// In that case we need only deoptimize and throw away all compiled code
+// that depends on the class.
+//
+// If can_redefine_classes is obtained sometime after the onload
+// phase then the dependency information may be incomplete. In that case
+// the first call to RedefineClasses causes all compiled code to be
+// thrown away. As can_redefine_classes has been obtained then
+// all future compilations will record dependencies so second and
+// subsequent calls to RedefineClasses need only throw away code
+// that depends on the class.
+//
+void VM_RedefineClasses::flush_dependent_code(instanceKlassHandle k_h, TRAPS) {
+assert_locked_or_safepoint(Compile_lock);
+// All dependencies have been recorded from startup or this is a second or
+// subsequent use of RedefineClasses
+if (JvmtiExport::all_dependencies_are_recorded()) {
+Universe::flush_evol_dependents_on(k_h);
+} else {
+CodeCache::mark_all_nmethods_for_deoptimization();
+ResourceMark rm(THREAD);
+DeoptimizationMarker dm;
+// Deoptimize all activations depending on marked nmethods
+Deoptimization::deoptimize_dependents();
+// Make the dependent methods not entrant (in VM_Deoptimize they are made zombies)
+CodeCache::make_marked_nmethods_not_entrant();
+// From now on we know that the dependency information is complete
+JvmtiExport::set_all_dependencies_are_recorded(true);
+}
+}
+void VM_RedefineClasses::compute_added_deleted_matching_methods() {
+methodOop old_method;
+methodOop new_method;
+_matching_old_methods = NEW_RESOURCE_ARRAY(methodOop, _old_methods->length());
+_matching_new_methods = NEW_RESOURCE_ARRAY(methodOop, _old_methods->length());
+_added_methods        = NEW_RESOURCE_ARRAY(methodOop, _new_methods->length());
+_deleted_methods      = NEW_RESOURCE_ARRAY(methodOop, _old_methods->length());
+_matching_methods_length = 0;
+_deleted_methods_length  = 0;
+_added_methods_length    = 0;
+int nj = 0;
+int oj = 0;
+while (true) {
+if (oj >= _old_methods->length()) {
+if (nj >= _new_methods->length()) {
+break; // we've looked at everything, done
+}
+// New method at the end
+new_method = (methodOop) _new_methods->obj_at(nj);
+_added_methods[_added_methods_length++] = new_method;
+++nj;
+} else if (nj >= _new_methods->length()) {
+// Old method, at the end, is deleted
+old_method = (methodOop) _old_methods->obj_at(oj);
+_deleted_methods[_deleted_methods_length++] = old_method;
+++oj;
+} else {
+old_method = (methodOop) _old_methods->obj_at(oj);
+new_method = (methodOop) _new_methods->obj_at(nj);
+if (old_method->name() == new_method->name()) {
+if (old_method->signature() == new_method->signature()) {
+_matching_old_methods[_matching_methods_length  ] = old_method;
+_matching_new_methods[_matching_methods_length++] = new_method;
+++nj;
+++oj;
+} else {
+// added overloaded have already been moved to the end,
+// so this is a deleted overloaded method
+_deleted_methods[_deleted_methods_length++] = old_method;
+++oj;
+}
+} else { // names don't match
+if (old_method->name()->fast_compare(new_method->name()) > 0) {
+// new method
+_added_methods[_added_methods_length++] = new_method;
+++nj;
+} else {
+// deleted method
+_deleted_methods[_deleted_methods_length++] = old_method;
+++oj;
+}
+}
+}
+}
+assert(_matching_methods_length + _deleted_methods_length == _old_methods->length(), "sanity");
+assert(_matching_methods_length + _added_methods_length == _new_methods->length(), "sanity");
+}
+// Install the redefinition of a class:
+//    - house keeping (flushing breakpoints and caches, deoptimizing
+//      dependent compiled code)
+//    - replacing parts in the_class with parts from scratch_class
+//    - adding a weak reference to track the obsolete but interesting
+//      parts of the_class
+//    - adjusting constant pool caches and vtables in other classes
+//      that refer to methods in the_class. These adjustments use the
+//      SystemDictionary::classes_do() facility which only allows
+//      a helper method to be specified. The interesting parameters
+//      that we would like to pass to the helper method are saved in
+//      static global fields in the VM operation.
+void VM_RedefineClasses::redefine_single_class(jclass the_jclass,
+instanceKlassHandle scratch_class, TRAPS) {
+RC_TIMER_START(_timer_rsc_phase1);
+oop the_class_mirror = JNIHandles::resolve_non_null(the_jclass);
+klassOop the_class_oop = java_lang_Class::as_klassOop(the_class_mirror);
+instanceKlassHandle the_class = instanceKlassHandle(THREAD, the_class_oop);
+#ifndef JVMTI_KERNEL
+// Remove all breakpoints in methods of this class
+JvmtiBreakpoints& jvmti_breakpoints = JvmtiCurrentBreakpoints::get_jvmti_breakpoints();
+jvmti_breakpoints.clearall_in_class_at_safepoint(the_class_oop);
+#endif // !JVMTI_KERNEL
+if (the_class_oop == Universe::reflect_invoke_cache()->klass()) {
+// We are redefining java.lang.reflect.Method. Method.invoke() is
+// cached and users of the cache care about each active version of
+// the method so we have to track this previous version.
+// Do this before methods get switched
+Universe::reflect_invoke_cache()->add_previous_version(
+the_class->method_with_idnum(Universe::reflect_invoke_cache()->method_idnum()));
+}
+// Deoptimize all compiled code that depends on this class
+flush_dependent_code(the_class, THREAD);
+_old_methods = the_class->methods();
+_new_methods = scratch_class->methods();
+_the_class_oop = the_class_oop;
+compute_added_deleted_matching_methods();
+update_jmethod_ids();
+// Attach new constant pool to the original klass. The original
+// klass still refers to the old constant pool (for now).
+scratch_class->constants()->set_pool_holder(the_class());
+#if 0
+// In theory, with constant pool merging in place we should be able
+// to save space by using the new, merged constant pool in place of
+// the old constant pool(s). By "pool(s)" I mean the constant pool in
+// the klass version we are replacing now and any constant pool(s) in
+// previous versions of klass. Nice theory, doesn't work in practice.
+// When this code is enabled, even simple programs throw NullPointer
+// exceptions. I'm guessing that this is caused by some constant pool
+// cache difference between the new, merged constant pool and the
+// constant pool that was just being used by the klass. I'm keeping
+// this code around to archive the idea, but the code has to remain
+// disabled for now.
+// Attach each old method to the new constant pool. This can be
+// done here since we are past the bytecode verification and
+// constant pool optimization phases.
+for (int i = _old_methods->length() - 1; i >= 0; i--) {
+methodOop method = (methodOop)_old_methods->obj_at(i);
+method->set_constants(scratch_class->constants());
+}
+{
+// walk all previous versions of the klass
+instanceKlass *ik = (instanceKlass *)the_class()->klass_part();
+PreviousVersionWalker pvw(ik);
+instanceKlassHandle ikh;
+do {
+ikh = pvw.next_previous_version();
+if (!ikh.is_null()) {
+ik = ikh();
+// attach previous version of klass to the new constant pool
+ik->set_constants(scratch_class->constants());
+// Attach each method in the previous version of klass to the
+// new constant pool
+objArrayOop prev_methods = ik->methods();
+for (int i = prev_methods->length() - 1; i >= 0; i--) {
+methodOop method = (methodOop)prev_methods->obj_at(i);
+method->set_constants(scratch_class->constants());
+}
+}
+} while (!ikh.is_null());
+}
+#endif
+// Replace methods and constantpool
+the_class->set_methods(_new_methods);
+scratch_class->set_methods(_old_methods);     // To prevent potential GCing of the old methods,
+// and to be able to undo operation easily.
+constantPoolOop old_constants = the_class->constants();
+the_class->set_constants(scratch_class->constants());
+scratch_class->set_constants(old_constants);  // See the previous comment.
+#if 0
+// We are swapping the guts of "the new class" with the guts of "the
+// class". Since the old constant pool has just been attached to "the
+// new class", it seems logical to set the pool holder in the old
+// constant pool also. However, doing this will change the observable
+// class hierarchy for any old methods that are still executing. A
+// method can query the identity of its "holder" and this query uses
+// the method's constant pool link to find the holder. The change in
+// holding class from "the class" to "the new class" can confuse
+// things.
+//
+// Setting the old constant pool's holder will also cause
+// verification done during vtable initialization below to fail.
+// During vtable initialization, the vtable's class is verified to be
+// a subtype of the method's holder. The vtable's class is "the
+// class" and the method's holder is gotten from the constant pool
+// link in the method itself. For "the class"'s directly implemented
+// methods, the method holder is "the class" itself (as gotten from
+// the new constant pool). The check works fine in this case. The
+// check also works fine for methods inherited from super classes.
+//
+// Miranda methods are a little more complicated. A miranda method is
+// provided by an interface when the class implementing the interface
+// does not provide its own method.  These interfaces are implemented
+// internally as an instanceKlass. These special instanceKlasses
+// share the constant pool of the class that "implements" the
+// interface. By sharing the constant pool, the method holder of a
+// miranda method is the class that "implements" the interface. In a
+// non-redefine situation, the subtype check works fine. However, if
+// the old constant pool's pool holder is modified, then the check
+// fails because there is no class hierarchy relationship between the
+// vtable's class and "the new class".
+old_constants->set_pool_holder(scratch_class());
+#endif
+// track which methods are EMCP for add_previous_version() call below
+BitMap emcp_methods(_old_methods->length());
+int emcp_method_count = 0;
+emcp_methods.clear();  // clears 0..(length() - 1)
+check_methods_and_mark_as_obsolete(&emcp_methods, &emcp_method_count);
+transfer_old_native_function_registrations(the_class);
+// The class file bytes from before any retransformable agents mucked
+// with them was cached on the scratch class, move to the_class.
+// Note: we still want to do this if nothing needed caching since it
+// should get cleared in the_class too.
+the_class->set_cached_class_file(scratch_class->get_cached_class_file_bytes(),
+scratch_class->get_cached_class_file_len());
+// Replace inner_classes
+typeArrayOop old_inner_classes = the_class->inner_classes();
+the_class->set_inner_classes(scratch_class->inner_classes());
+scratch_class->set_inner_classes(old_inner_classes);
+// Initialize the vtable and interface table after
+// methods have been rewritten
+{
+ResourceMark rm(THREAD);
+// no exception should happen here since we explicitly
+// do not check loader constraints.
+// compare_and_normalize_class_versions has already checked:
+//  - classloaders unchanged, signatures unchanged
+//  - all instanceKlasses for redefined classes reused & contents updated
+the_class->vtable()->initialize_vtable(false, THREAD);
+the_class->itable()->initialize_itable(false, THREAD);
+assert(!HAS_PENDING_EXCEPTION || (THREAD->pending_exception()->is_a(SystemDictionary::threaddeath_klass())), "redefine exception");
+}
+// Leave arrays of jmethodIDs and itable index cache unchanged
+// Copy the "source file name" attribute from new class version
+the_class->set_source_file_name(scratch_class->source_file_name());
+// Copy the "source debug extension" attribute from new class version
+the_class->set_source_debug_extension(
+scratch_class->source_debug_extension());
+// Use of javac -g could be different in the old and the new
+if (scratch_class->access_flags().has_localvariable_table() !=
+the_class->access_flags().has_localvariable_table()) {
+AccessFlags flags = the_class->access_flags();
+if (scratch_class->access_flags().has_localvariable_table()) {
+flags.set_has_localvariable_table();
+} else {
+flags.clear_has_localvariable_table();
+}
+the_class->set_access_flags(flags);
+}
+// Replace class annotation fields values
+typeArrayOop old_class_annotations = the_class->class_annotations();
+the_class->set_class_annotations(scratch_class->class_annotations());
+scratch_class->set_class_annotations(old_class_annotations);
+// Replace fields annotation fields values
+objArrayOop old_fields_annotations = the_class->fields_annotations();
+the_class->set_fields_annotations(scratch_class->fields_annotations());
+scratch_class->set_fields_annotations(old_fields_annotations);
+// Replace methods annotation fields values
+objArrayOop old_methods_annotations = the_class->methods_annotations();
+the_class->set_methods_annotations(scratch_class->methods_annotations());
+scratch_class->set_methods_annotations(old_methods_annotations);
+// Replace methods parameter annotation fields values
+objArrayOop old_methods_parameter_annotations =
+the_class->methods_parameter_annotations();
+the_class->set_methods_parameter_annotations(
+scratch_class->methods_parameter_annotations());
+scratch_class->set_methods_parameter_annotations(old_methods_parameter_annotations);
+// Replace methods default annotation fields values
+objArrayOop old_methods_default_annotations =
+the_class->methods_default_annotations();
+the_class->set_methods_default_annotations(
+scratch_class->methods_default_annotations());
+scratch_class->set_methods_default_annotations(old_methods_default_annotations);
+// Replace minor version number of class file
+u2 old_minor_version = the_class->minor_version();
+the_class->set_minor_version(scratch_class->minor_version());
+scratch_class->set_minor_version(old_minor_version);
+// Replace major version number of class file
+u2 old_major_version = the_class->major_version();
+the_class->set_major_version(scratch_class->major_version());
+scratch_class->set_major_version(old_major_version);
+// Replace CP indexes for class and name+type of enclosing method
+u2 old_class_idx  = the_class->enclosing_method_class_index();
+u2 old_method_idx = the_class->enclosing_method_method_index();
+the_class->set_enclosing_method_indices(
+scratch_class->enclosing_method_class_index(),
+scratch_class->enclosing_method_method_index());
+scratch_class->set_enclosing_method_indices(old_class_idx, old_method_idx);
+// keep track of previous versions of this class
+the_class->add_previous_version(scratch_class, &emcp_methods,
+emcp_method_count);
+RC_TIMER_STOP(_timer_rsc_phase1);
+RC_TIMER_START(_timer_rsc_phase2);
+// Adjust constantpool caches and vtables for all classes
+// that reference methods of the evolved class.
+SystemDictionary::classes_do(adjust_cpool_cache_and_vtable, THREAD);
+if (the_class->oop_map_cache() != NULL) {
+// Flush references to any obsolete methods from the oop map cache
+// so that obsolete methods are not pinned.
+the_class->oop_map_cache()->flush_obsolete_entries();
+}
+// increment the classRedefinedCount field in the_class and in any
+// direct and indirect subclasses of the_class
+increment_class_counter((instanceKlass *)the_class()->klass_part(), THREAD);
+// RC_TRACE macro has an embedded ResourceMark
+RC_TRACE_WITH_THREAD(0x00000001, THREAD,
+("redefined name=%s, count=%d (avail_mem=" UINT64_FORMAT "K)",
+the_class->external_name(),
+java_lang_Class::classRedefinedCount(the_class_mirror),
+os::available_memory() >> 10));
+RC_TIMER_STOP(_timer_rsc_phase2);
+} // end redefine_single_class()
+// Increment the classRedefinedCount field in the specific instanceKlass
+// and in all direct and indirect subclasses.
+void VM_RedefineClasses::increment_class_counter(instanceKlass *ik, TRAPS) {
+oop class_mirror = ik->java_mirror();
+klassOop class_oop = java_lang_Class::as_klassOop(class_mirror);
+int new_count = java_lang_Class::classRedefinedCount(class_mirror) + 1;
+java_lang_Class::set_classRedefinedCount(class_mirror, new_count);
+if (class_oop != _the_class_oop) {
+// _the_class_oop count is printed at end of redefine_single_class()
+RC_TRACE_WITH_THREAD(0x00000008, THREAD,
+("updated count in subclass=%s to %d", ik->external_name(), new_count));
+}
+for (Klass *subk = ik->subklass(); subk != NULL;
+subk = subk->next_sibling()) {
+klassOop sub = subk->as_klassOop();
+instanceKlass *subik = (instanceKlass *)sub->klass_part();
+// recursively do subclasses of the current subclass
+increment_class_counter(subik, THREAD);
+}
+}
+#ifndef PRODUCT
+void VM_RedefineClasses::check_class(klassOop k_oop,
+oop initiating_loader, TRAPS) {
+Klass *k = k_oop->klass_part();
+if (k->oop_is_instance()) {
+HandleMark hm(THREAD);
+instanceKlass *ik = (instanceKlass *) k;
+if (ik->vtable_length() > 0) {
+ResourceMark rm(THREAD);
+if (!ik->vtable()->check_no_old_entries()) {
+tty->print_cr("klassVtable::check_no_old_entries failure -- OLD method found -- class: %s", ik->signature_name());
+ik->vtable()->dump_vtable();
+dump_methods();
+assert(false, "OLD method found");
+}
+}
+}
+}
+void VM_RedefineClasses::dump_methods() {
+int j;
+tty->print_cr("_old_methods --");
+for (j = 0; j < _old_methods->length(); ++j) {
+methodOop m = (methodOop) _old_methods->obj_at(j);
+tty->print("%4d  (%5d)  ", j, m->vtable_index());
+m->access_flags().print_on(tty);
+tty->print(" --  ");
+m->print_name(tty);
+tty->cr();
+}
+tty->print_cr("_new_methods --");
+for (j = 0; j < _new_methods->length(); ++j) {
+methodOop m = (methodOop) _new_methods->obj_at(j);
+tty->print("%4d  (%5d)  ", j, m->vtable_index());
+m->access_flags().print_on(tty);
+tty->print(" --  ");
+m->print_name(tty);
+tty->cr();
+}
+tty->print_cr("_matching_(old/new)_methods --");
+for (j = 0; j < _matching_methods_length; ++j) {
+methodOop m = _matching_old_methods[j];
+tty->print("%4d  (%5d)  ", j, m->vtable_index());
+m->access_flags().print_on(tty);
+tty->print(" --  ");
+m->print_name(tty);
+tty->cr();
+m = _matching_new_methods[j];
+tty->print("      (%5d)  ", m->vtable_index());
+m->access_flags().print_on(tty);
+tty->cr();
+}
+tty->print_cr("_deleted_methods --");
+for (j = 0; j < _deleted_methods_length; ++j) {
+methodOop m = _deleted_methods[j];
+tty->print("%4d  (%5d)  ", j, m->vtable_index());
+m->access_flags().print_on(tty);
+tty->print(" --  ");
+m->print_name(tty);
+tty->cr();
+}
+tty->print_cr("_added_methods --");
+for (j = 0; j < _added_methods_length; ++j) {
+methodOop m = _added_methods[j];
+tty->print("%4d  (%5d)  ", j, m->vtable_index());
+m->access_flags().print_on(tty);
+tty->print(" --  ");
+m->print_name(tty);
+tty->cr();
+}
+}
+#endif

Mercurial > hg > truffle

comparison src/share/vm/prims/jvmtiRedefineClasses.cpp @ 0:a61af66fc99e jdk7-b24