--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/src/share/vm/prims/jvmtiRedefineClasses.cpp Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,3398 @@
+/*
+ * Copyright 2003-2007 Sun Microsystems, Inc. All Rights Reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ *
+ */
+
+# include "incls/_precompiled.incl"
+# include "incls/_jvmtiRedefineClasses.cpp.incl"
+
+
+objArrayOop VM_RedefineClasses::_old_methods = NULL;
+objArrayOop VM_RedefineClasses::_new_methods = NULL;
+methodOop* VM_RedefineClasses::_matching_old_methods = NULL;
+methodOop* VM_RedefineClasses::_matching_new_methods = NULL;
+methodOop* VM_RedefineClasses::_deleted_methods = NULL;
+methodOop* VM_RedefineClasses::_added_methods = NULL;
+int VM_RedefineClasses::_matching_methods_length = 0;
+int VM_RedefineClasses::_deleted_methods_length = 0;
+int VM_RedefineClasses::_added_methods_length = 0;
+klassOop VM_RedefineClasses::_the_class_oop = NULL;
+
+
+VM_RedefineClasses::VM_RedefineClasses(jint class_count,
+ const jvmtiClassDefinition *class_defs,
+ JvmtiClassLoadKind class_load_kind) {
+ _class_count = class_count;
+ _class_defs = class_defs;
+ _class_load_kind = class_load_kind;
+ _res = JVMTI_ERROR_NONE;
+}
+
+bool VM_RedefineClasses::doit_prologue() {
+ if (_class_count == 0) {
+ _res = JVMTI_ERROR_NONE;
+ return false;
+ }
+ if (_class_defs == NULL) {
+ _res = JVMTI_ERROR_NULL_POINTER;
+ return false;
+ }
+ for (int i = 0; i < _class_count; i++) {
+ if (_class_defs[i].klass == NULL) {
+ _res = JVMTI_ERROR_INVALID_CLASS;
+ return false;
+ }
+ if (_class_defs[i].class_byte_count == 0) {
+ _res = JVMTI_ERROR_INVALID_CLASS_FORMAT;
+ return false;
+ }
+ if (_class_defs[i].class_bytes == NULL) {
+ _res = JVMTI_ERROR_NULL_POINTER;
+ return false;
+ }
+ }
+
+ // Start timer after all the sanity checks; not quite accurate, but
+ // better than adding a bunch of stop() calls.
+ RC_TIMER_START(_timer_vm_op_prologue);
+
+ // We first load new class versions in the prologue, because somewhere down the
+ // call chain it is required that the current thread is a Java thread.
+ _res = load_new_class_versions(Thread::current());
+ if (_res != JVMTI_ERROR_NONE) {
+ // Free os::malloc allocated memory in load_new_class_version.
+ os::free(_scratch_classes);
+ RC_TIMER_STOP(_timer_vm_op_prologue);
+ return false;
+ }
+
+ RC_TIMER_STOP(_timer_vm_op_prologue);
+ return true;
+}
+
+void VM_RedefineClasses::doit() {
+ Thread *thread = Thread::current();
+
+ if (UseSharedSpaces) {
+ // Sharing is enabled so we remap the shared readonly space to
+ // shared readwrite, private just in case we need to redefine
+ // a shared class. We do the remap during the doit() phase of
+ // the safepoint to be safer.
+ if (!CompactingPermGenGen::remap_shared_readonly_as_readwrite()) {
+ RC_TRACE_WITH_THREAD(0x00000001, thread,
+ ("failed to remap shared readonly space to readwrite, private"));
+ _res = JVMTI_ERROR_INTERNAL;
+ return;
+ }
+ }
+
+ for (int i = 0; i < _class_count; i++) {
+ redefine_single_class(_class_defs[i].klass, _scratch_classes[i], thread);
+ }
+ // Disable any dependent concurrent compilations
+ SystemDictionary::notice_modification();
+
+ // Set flag indicating that some invariants are no longer true.
+ // See jvmtiExport.hpp for detailed explanation.
+ JvmtiExport::set_has_redefined_a_class();
+
+#ifdef ASSERT
+ SystemDictionary::classes_do(check_class, thread);
+#endif
+}
+
+void VM_RedefineClasses::doit_epilogue() {
+ // Free os::malloc allocated memory.
+ // The memory allocated in redefine will be free'ed in next VM operation.
+ os::free(_scratch_classes);
+
+ if (RC_TRACE_ENABLED(0x00000004)) {
+ // Used to have separate timers for "doit" and "all", but the timer
+ // overhead skewed the measurements.
+ jlong doit_time = _timer_rsc_phase1.milliseconds() +
+ _timer_rsc_phase2.milliseconds();
+ jlong all_time = _timer_vm_op_prologue.milliseconds() + doit_time;
+
+ RC_TRACE(0x00000004, ("vm_op: all=" UINT64_FORMAT
+ " prologue=" UINT64_FORMAT " doit=" UINT64_FORMAT, all_time,
+ _timer_vm_op_prologue.milliseconds(), doit_time));
+ RC_TRACE(0x00000004,
+ ("redefine_single_class: phase1=" UINT64_FORMAT " phase2=" UINT64_FORMAT,
+ _timer_rsc_phase1.milliseconds(), _timer_rsc_phase2.milliseconds()));
+ }
+}
+
+bool VM_RedefineClasses::is_modifiable_class(oop klass_mirror) {
+ // classes for primitives cannot be redefined
+ if (java_lang_Class::is_primitive(klass_mirror)) {
+ return false;
+ }
+ klassOop the_class_oop = java_lang_Class::as_klassOop(klass_mirror);
+ // classes for arrays cannot be redefined
+ if (the_class_oop == NULL || !Klass::cast(the_class_oop)->oop_is_instance()) {
+ return false;
+ }
+ return true;
+}
+
+// Append the current entry at scratch_i in scratch_cp to *merge_cp_p
+// where the end of *merge_cp_p is specified by *merge_cp_length_p. For
+// direct CP entries, there is just the current entry to append. For
+// indirect and double-indirect CP entries, there are zero or more
+// referenced CP entries along with the current entry to append.
+// Indirect and double-indirect CP entries are handled by recursive
+// calls to append_entry() as needed. The referenced CP entries are
+// always appended to *merge_cp_p before the referee CP entry. These
+// referenced CP entries may already exist in *merge_cp_p in which case
+// there is nothing extra to append and only the current entry is
+// appended.
+void VM_RedefineClasses::append_entry(constantPoolHandle scratch_cp,
+ int scratch_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p,
+ TRAPS) {
+
+ // append is different depending on entry tag type
+ switch (scratch_cp->tag_at(scratch_i).value()) {
+
+ // The old verifier is implemented outside the VM. It loads classes,
+ // but does not resolve constant pool entries directly so we never
+ // see Class entries here with the old verifier. Similarly the old
+ // verifier does not like Class entries in the input constant pool.
+ // The split-verifier is implemented in the VM so it can optionally
+ // and directly resolve constant pool entries to load classes. The
+ // split-verifier can accept either Class entries or UnresolvedClass
+ // entries in the input constant pool. We revert the appended copy
+ // back to UnresolvedClass so that either verifier will be happy
+ // with the constant pool entry.
+ case JVM_CONSTANT_Class:
+ {
+ // revert the copy to JVM_CONSTANT_UnresolvedClass
+ (*merge_cp_p)->unresolved_klass_at_put(*merge_cp_length_p,
+ scratch_cp->klass_name_at(scratch_i));
+
+ if (scratch_i != *merge_cp_length_p) {
+ // The new entry in *merge_cp_p is at a different index than
+ // the new entry in scratch_cp so we need to map the index values.
+ map_index(scratch_cp, scratch_i, *merge_cp_length_p);
+ }
+ (*merge_cp_length_p)++;
+ } break;
+
+ // these are direct CP entries so they can be directly appended,
+ // but double and long take two constant pool entries
+ case JVM_CONSTANT_Double: // fall through
+ case JVM_CONSTANT_Long:
+ {
+ scratch_cp->copy_entry_to(scratch_i, *merge_cp_p, *merge_cp_length_p,
+ THREAD);
+
+ if (scratch_i != *merge_cp_length_p) {
+ // The new entry in *merge_cp_p is at a different index than
+ // the new entry in scratch_cp so we need to map the index values.
+ map_index(scratch_cp, scratch_i, *merge_cp_length_p);
+ }
+ (*merge_cp_length_p) += 2;
+ } break;
+
+ // these are direct CP entries so they can be directly appended
+ case JVM_CONSTANT_Float: // fall through
+ case JVM_CONSTANT_Integer: // fall through
+ case JVM_CONSTANT_Utf8: // fall through
+
+ // This was an indirect CP entry, but it has been changed into
+ // an interned string so this entry can be directly appended.
+ case JVM_CONSTANT_String: // fall through
+
+ // These were indirect CP entries, but they have been changed into
+ // symbolOops so these entries can be directly appended.
+ case JVM_CONSTANT_UnresolvedClass: // fall through
+ case JVM_CONSTANT_UnresolvedString:
+ {
+ scratch_cp->copy_entry_to(scratch_i, *merge_cp_p, *merge_cp_length_p,
+ THREAD);
+
+ if (scratch_i != *merge_cp_length_p) {
+ // The new entry in *merge_cp_p is at a different index than
+ // the new entry in scratch_cp so we need to map the index values.
+ map_index(scratch_cp, scratch_i, *merge_cp_length_p);
+ }
+ (*merge_cp_length_p)++;
+ } break;
+
+ // this is an indirect CP entry so it needs special handling
+ case JVM_CONSTANT_NameAndType:
+ {
+ int name_ref_i = scratch_cp->name_ref_index_at(scratch_i);
+ int new_name_ref_i = 0;
+ bool match = (name_ref_i < *merge_cp_length_p) &&
+ scratch_cp->compare_entry_to(name_ref_i, *merge_cp_p, name_ref_i,
+ THREAD);
+ if (!match) {
+ // forward reference in *merge_cp_p or not a direct match
+
+ int found_i = scratch_cp->find_matching_entry(name_ref_i, *merge_cp_p,
+ THREAD);
+ if (found_i != 0) {
+ guarantee(found_i != name_ref_i,
+ "compare_entry_to() and find_matching_entry() do not agree");
+
+ // Found a matching entry somewhere else in *merge_cp_p so
+ // just need a mapping entry.
+ new_name_ref_i = found_i;
+ map_index(scratch_cp, name_ref_i, found_i);
+ } else {
+ // no match found so we have to append this entry to *merge_cp_p
+ append_entry(scratch_cp, name_ref_i, merge_cp_p, merge_cp_length_p,
+ THREAD);
+ // The above call to append_entry() can only append one entry
+ // so the post call query of *merge_cp_length_p is only for
+ // the sake of consistency.
+ new_name_ref_i = *merge_cp_length_p - 1;
+ }
+ }
+
+ int signature_ref_i = scratch_cp->signature_ref_index_at(scratch_i);
+ int new_signature_ref_i = 0;
+ match = (signature_ref_i < *merge_cp_length_p) &&
+ scratch_cp->compare_entry_to(signature_ref_i, *merge_cp_p,
+ signature_ref_i, THREAD);
+ if (!match) {
+ // forward reference in *merge_cp_p or not a direct match
+
+ int found_i = scratch_cp->find_matching_entry(signature_ref_i,
+ *merge_cp_p, THREAD);
+ if (found_i != 0) {
+ guarantee(found_i != signature_ref_i,
+ "compare_entry_to() and find_matching_entry() do not agree");
+
+ // Found a matching entry somewhere else in *merge_cp_p so
+ // just need a mapping entry.
+ new_signature_ref_i = found_i;
+ map_index(scratch_cp, signature_ref_i, found_i);
+ } else {
+ // no match found so we have to append this entry to *merge_cp_p
+ append_entry(scratch_cp, signature_ref_i, merge_cp_p,
+ merge_cp_length_p, THREAD);
+ // The above call to append_entry() can only append one entry
+ // so the post call query of *merge_cp_length_p is only for
+ // the sake of consistency.
+ new_signature_ref_i = *merge_cp_length_p - 1;
+ }
+ }
+
+ // If the referenced entries already exist in *merge_cp_p, then
+ // both new_name_ref_i and new_signature_ref_i will both be 0.
+ // In that case, all we are appending is the current entry.
+ if (new_name_ref_i == 0) {
+ new_name_ref_i = name_ref_i;
+ } else {
+ RC_TRACE(0x00080000,
+ ("NameAndType entry@%d name_ref_index change: %d to %d",
+ *merge_cp_length_p, name_ref_i, new_name_ref_i));
+ }
+ if (new_signature_ref_i == 0) {
+ new_signature_ref_i = signature_ref_i;
+ } else {
+ RC_TRACE(0x00080000,
+ ("NameAndType entry@%d signature_ref_index change: %d to %d",
+ *merge_cp_length_p, signature_ref_i, new_signature_ref_i));
+ }
+
+ (*merge_cp_p)->name_and_type_at_put(*merge_cp_length_p,
+ new_name_ref_i, new_signature_ref_i);
+ if (scratch_i != *merge_cp_length_p) {
+ // The new entry in *merge_cp_p is at a different index than
+ // the new entry in scratch_cp so we need to map the index values.
+ map_index(scratch_cp, scratch_i, *merge_cp_length_p);
+ }
+ (*merge_cp_length_p)++;
+ } break;
+
+ // this is a double-indirect CP entry so it needs special handling
+ case JVM_CONSTANT_Fieldref: // fall through
+ case JVM_CONSTANT_InterfaceMethodref: // fall through
+ case JVM_CONSTANT_Methodref:
+ {
+ int klass_ref_i = scratch_cp->uncached_klass_ref_index_at(scratch_i);
+ int new_klass_ref_i = 0;
+ bool match = (klass_ref_i < *merge_cp_length_p) &&
+ scratch_cp->compare_entry_to(klass_ref_i, *merge_cp_p, klass_ref_i,
+ THREAD);
+ if (!match) {
+ // forward reference in *merge_cp_p or not a direct match
+
+ int found_i = scratch_cp->find_matching_entry(klass_ref_i, *merge_cp_p,
+ THREAD);
+ if (found_i != 0) {
+ guarantee(found_i != klass_ref_i,
+ "compare_entry_to() and find_matching_entry() do not agree");
+
+ // Found a matching entry somewhere else in *merge_cp_p so
+ // just need a mapping entry.
+ new_klass_ref_i = found_i;
+ map_index(scratch_cp, klass_ref_i, found_i);
+ } else {
+ // no match found so we have to append this entry to *merge_cp_p
+ append_entry(scratch_cp, klass_ref_i, merge_cp_p, merge_cp_length_p,
+ THREAD);
+ // The above call to append_entry() can only append one entry
+ // so the post call query of *merge_cp_length_p is only for
+ // the sake of consistency. Without the optimization where we
+ // use JVM_CONSTANT_UnresolvedClass, then up to two entries
+ // could be appended.
+ new_klass_ref_i = *merge_cp_length_p - 1;
+ }
+ }
+
+ int name_and_type_ref_i =
+ scratch_cp->uncached_name_and_type_ref_index_at(scratch_i);
+ int new_name_and_type_ref_i = 0;
+ match = (name_and_type_ref_i < *merge_cp_length_p) &&
+ scratch_cp->compare_entry_to(name_and_type_ref_i, *merge_cp_p,
+ name_and_type_ref_i, THREAD);
+ if (!match) {
+ // forward reference in *merge_cp_p or not a direct match
+
+ int found_i = scratch_cp->find_matching_entry(name_and_type_ref_i,
+ *merge_cp_p, THREAD);
+ if (found_i != 0) {
+ guarantee(found_i != name_and_type_ref_i,
+ "compare_entry_to() and find_matching_entry() do not agree");
+
+ // Found a matching entry somewhere else in *merge_cp_p so
+ // just need a mapping entry.
+ new_name_and_type_ref_i = found_i;
+ map_index(scratch_cp, name_and_type_ref_i, found_i);
+ } else {
+ // no match found so we have to append this entry to *merge_cp_p
+ append_entry(scratch_cp, name_and_type_ref_i, merge_cp_p,
+ merge_cp_length_p, THREAD);
+ // The above call to append_entry() can append more than
+ // one entry so the post call query of *merge_cp_length_p
+ // is required in order to get the right index for the
+ // JVM_CONSTANT_NameAndType entry.
+ new_name_and_type_ref_i = *merge_cp_length_p - 1;
+ }
+ }
+
+ // If the referenced entries already exist in *merge_cp_p, then
+ // both new_klass_ref_i and new_name_and_type_ref_i will both be
+ // 0. In that case, all we are appending is the current entry.
+ if (new_klass_ref_i == 0) {
+ new_klass_ref_i = klass_ref_i;
+ }
+ if (new_name_and_type_ref_i == 0) {
+ new_name_and_type_ref_i = name_and_type_ref_i;
+ }
+
+ const char *entry_name;
+ switch (scratch_cp->tag_at(scratch_i).value()) {
+ case JVM_CONSTANT_Fieldref:
+ entry_name = "Fieldref";
+ (*merge_cp_p)->field_at_put(*merge_cp_length_p, new_klass_ref_i,
+ new_name_and_type_ref_i);
+ break;
+ case JVM_CONSTANT_InterfaceMethodref:
+ entry_name = "IFMethodref";
+ (*merge_cp_p)->interface_method_at_put(*merge_cp_length_p,
+ new_klass_ref_i, new_name_and_type_ref_i);
+ break;
+ case JVM_CONSTANT_Methodref:
+ entry_name = "Methodref";
+ (*merge_cp_p)->method_at_put(*merge_cp_length_p, new_klass_ref_i,
+ new_name_and_type_ref_i);
+ break;
+ default:
+ guarantee(false, "bad switch");
+ break;
+ }
+
+ if (klass_ref_i != new_klass_ref_i) {
+ RC_TRACE(0x00080000, ("%s entry@%d class_index changed: %d to %d",
+ entry_name, *merge_cp_length_p, klass_ref_i, new_klass_ref_i));
+ }
+ if (name_and_type_ref_i != new_name_and_type_ref_i) {
+ RC_TRACE(0x00080000,
+ ("%s entry@%d name_and_type_index changed: %d to %d",
+ entry_name, *merge_cp_length_p, name_and_type_ref_i,
+ new_name_and_type_ref_i));
+ }
+
+ if (scratch_i != *merge_cp_length_p) {
+ // The new entry in *merge_cp_p is at a different index than
+ // the new entry in scratch_cp so we need to map the index values.
+ map_index(scratch_cp, scratch_i, *merge_cp_length_p);
+ }
+ (*merge_cp_length_p)++;
+ } break;
+
+ // At this stage, Class or UnresolvedClass could be here, but not
+ // ClassIndex
+ case JVM_CONSTANT_ClassIndex: // fall through
+
+ // Invalid is used as the tag for the second constant pool entry
+ // occupied by JVM_CONSTANT_Double or JVM_CONSTANT_Long. It should
+ // not be seen by itself.
+ case JVM_CONSTANT_Invalid: // fall through
+
+ // At this stage, String or UnresolvedString could be here, but not
+ // StringIndex
+ case JVM_CONSTANT_StringIndex: // fall through
+
+ // At this stage JVM_CONSTANT_UnresolvedClassInError should not be
+ // here
+ case JVM_CONSTANT_UnresolvedClassInError: // fall through
+
+ default:
+ {
+ // leave a breadcrumb
+ jbyte bad_value = scratch_cp->tag_at(scratch_i).value();
+ ShouldNotReachHere();
+ } break;
+ } // end switch tag value
+} // end append_entry()
+
+
+void VM_RedefineClasses::swap_all_method_annotations(int i, int j, instanceKlassHandle scratch_class) {
+ typeArrayOop save;
+
+ save = scratch_class->get_method_annotations_of(i);
+ scratch_class->set_method_annotations_of(i, scratch_class->get_method_annotations_of(j));
+ scratch_class->set_method_annotations_of(j, save);
+
+ save = scratch_class->get_method_parameter_annotations_of(i);
+ scratch_class->set_method_parameter_annotations_of(i, scratch_class->get_method_parameter_annotations_of(j));
+ scratch_class->set_method_parameter_annotations_of(j, save);
+
+ save = scratch_class->get_method_default_annotations_of(i);
+ scratch_class->set_method_default_annotations_of(i, scratch_class->get_method_default_annotations_of(j));
+ scratch_class->set_method_default_annotations_of(j, save);
+}
+
+
+jvmtiError VM_RedefineClasses::compare_and_normalize_class_versions(
+ instanceKlassHandle the_class,
+ instanceKlassHandle scratch_class) {
+ int i;
+
+ // Check superclasses, or rather their names, since superclasses themselves can be
+ // requested to replace.
+ // Check for NULL superclass first since this might be java.lang.Object
+ if (the_class->super() != scratch_class->super() &&
+ (the_class->super() == NULL || scratch_class->super() == NULL ||
+ Klass::cast(the_class->super())->name() !=
+ Klass::cast(scratch_class->super())->name())) {
+ return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
+ }
+
+ // Check if the number, names and order of directly implemented interfaces are the same.
+ // I think in principle we should just check if the sets of names of directly implemented
+ // interfaces are the same, i.e. the order of declaration (which, however, if changed in the
+ // .java file, also changes in .class file) should not matter. However, comparing sets is
+ // technically a bit more difficult, and, more importantly, I am not sure at present that the
+ // order of interfaces does not matter on the implementation level, i.e. that the VM does not
+ // rely on it somewhere.
+ objArrayOop k_interfaces = the_class->local_interfaces();
+ objArrayOop k_new_interfaces = scratch_class->local_interfaces();
+ int n_intfs = k_interfaces->length();
+ if (n_intfs != k_new_interfaces->length()) {
+ return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
+ }
+ for (i = 0; i < n_intfs; i++) {
+ if (Klass::cast((klassOop) k_interfaces->obj_at(i))->name() !=
+ Klass::cast((klassOop) k_new_interfaces->obj_at(i))->name()) {
+ return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
+ }
+ }
+
+ // Check whether class is in the error init state.
+ if (the_class->is_in_error_state()) {
+ // TBD #5057930: special error code is needed in 1.6
+ return JVMTI_ERROR_INVALID_CLASS;
+ }
+
+ // Check whether class modifiers are the same.
+ jushort old_flags = (jushort) the_class->access_flags().get_flags();
+ jushort new_flags = (jushort) scratch_class->access_flags().get_flags();
+ if (old_flags != new_flags) {
+ return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_MODIFIERS_CHANGED;
+ }
+
+ // Check if the number, names, types and order of fields declared in these classes
+ // are the same.
+ typeArrayOop k_old_fields = the_class->fields();
+ typeArrayOop k_new_fields = scratch_class->fields();
+ int n_fields = k_old_fields->length();
+ if (n_fields != k_new_fields->length()) {
+ return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
+ }
+
+ for (i = 0; i < n_fields; i += instanceKlass::next_offset) {
+ // access
+ old_flags = k_old_fields->ushort_at(i + instanceKlass::access_flags_offset);
+ new_flags = k_new_fields->ushort_at(i + instanceKlass::access_flags_offset);
+ if ((old_flags ^ new_flags) & JVM_RECOGNIZED_FIELD_MODIFIERS) {
+ return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
+ }
+ // offset
+ if (k_old_fields->short_at(i + instanceKlass::low_offset) !=
+ k_new_fields->short_at(i + instanceKlass::low_offset) ||
+ k_old_fields->short_at(i + instanceKlass::high_offset) !=
+ k_new_fields->short_at(i + instanceKlass::high_offset)) {
+ return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
+ }
+ // name and signature
+ jshort name_index = k_old_fields->short_at(i + instanceKlass::name_index_offset);
+ jshort sig_index = k_old_fields->short_at(i +instanceKlass::signature_index_offset);
+ symbolOop name_sym1 = the_class->constants()->symbol_at(name_index);
+ symbolOop sig_sym1 = the_class->constants()->symbol_at(sig_index);
+ name_index = k_new_fields->short_at(i + instanceKlass::name_index_offset);
+ sig_index = k_new_fields->short_at(i + instanceKlass::signature_index_offset);
+ symbolOop name_sym2 = scratch_class->constants()->symbol_at(name_index);
+ symbolOop sig_sym2 = scratch_class->constants()->symbol_at(sig_index);
+ if (name_sym1 != name_sym2 || sig_sym1 != sig_sym2) {
+ return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
+ }
+ }
+
+ // Do a parallel walk through the old and new methods. Detect
+ // cases where they match (exist in both), have been added in
+ // the new methods, or have been deleted (exist only in the
+ // old methods). The class file parser places methods in order
+ // by method name, but does not order overloaded methods by
+ // signature. In order to determine what fate befell the methods,
+ // this code places the overloaded new methods that have matching
+ // old methods in the same order as the old methods and places
+ // new overloaded methods at the end of overloaded methods of
+ // that name. The code for this order normalization is adapted
+ // from the algorithm used in instanceKlass::find_method().
+ // Since we are swapping out of order entries as we find them,
+ // we only have to search forward through the overloaded methods.
+ // Methods which are added and have the same name as an existing
+ // method (but different signature) will be put at the end of
+ // the methods with that name, and the name mismatch code will
+ // handle them.
+ objArrayHandle k_old_methods(the_class->methods());
+ objArrayHandle k_new_methods(scratch_class->methods());
+ int n_old_methods = k_old_methods->length();
+ int n_new_methods = k_new_methods->length();
+
+ int ni = 0;
+ int oi = 0;
+ while (true) {
+ methodOop k_old_method;
+ methodOop k_new_method;
+ enum { matched, added, deleted, undetermined } method_was = undetermined;
+
+ if (oi >= n_old_methods) {
+ if (ni >= n_new_methods) {
+ break; // we've looked at everything, done
+ }
+ // New method at the end
+ k_new_method = (methodOop) k_new_methods->obj_at(ni);
+ method_was = added;
+ } else if (ni >= n_new_methods) {
+ // Old method, at the end, is deleted
+ k_old_method = (methodOop) k_old_methods->obj_at(oi);
+ method_was = deleted;
+ } else {
+ // There are more methods in both the old and new lists
+ k_old_method = (methodOop) k_old_methods->obj_at(oi);
+ k_new_method = (methodOop) k_new_methods->obj_at(ni);
+ if (k_old_method->name() != k_new_method->name()) {
+ // Methods are sorted by method name, so a mismatch means added
+ // or deleted
+ if (k_old_method->name()->fast_compare(k_new_method->name()) > 0) {
+ method_was = added;
+ } else {
+ method_was = deleted;
+ }
+ } else if (k_old_method->signature() == k_new_method->signature()) {
+ // Both the name and signature match
+ method_was = matched;
+ } else {
+ // The name matches, but the signature doesn't, which means we have to
+ // search forward through the new overloaded methods.
+ int nj; // outside the loop for post-loop check
+ for (nj = ni + 1; nj < n_new_methods; nj++) {
+ methodOop m = (methodOop)k_new_methods->obj_at(nj);
+ if (k_old_method->name() != m->name()) {
+ // reached another method name so no more overloaded methods
+ method_was = deleted;
+ break;
+ }
+ if (k_old_method->signature() == m->signature()) {
+ // found a match so swap the methods
+ k_new_methods->obj_at_put(ni, m);
+ k_new_methods->obj_at_put(nj, k_new_method);
+ k_new_method = m;
+ method_was = matched;
+ break;
+ }
+ }
+
+ if (nj >= n_new_methods) {
+ // reached the end without a match; so method was deleted
+ method_was = deleted;
+ }
+ }
+ }
+
+ switch (method_was) {
+ case matched:
+ // methods match, be sure modifiers do too
+ old_flags = (jushort) k_old_method->access_flags().get_flags();
+ new_flags = (jushort) k_new_method->access_flags().get_flags();
+ if ((old_flags ^ new_flags) & ~(JVM_ACC_NATIVE)) {
+ return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_MODIFIERS_CHANGED;
+ }
+ {
+ u2 new_num = k_new_method->method_idnum();
+ u2 old_num = k_old_method->method_idnum();
+ if (new_num != old_num) {
+ methodOop idnum_owner = scratch_class->method_with_idnum(old_num);
+ if (idnum_owner != NULL) {
+ // There is already a method assigned this idnum -- switch them
+ idnum_owner->set_method_idnum(new_num);
+ }
+ k_new_method->set_method_idnum(old_num);
+ swap_all_method_annotations(old_num, new_num, scratch_class);
+ }
+ }
+ RC_TRACE(0x00008000, ("Method matched: new: %s [%d] == old: %s [%d]",
+ k_new_method->name_and_sig_as_C_string(), ni,
+ k_old_method->name_and_sig_as_C_string(), oi));
+ // advance to next pair of methods
+ ++oi;
+ ++ni;
+ break;
+ case added:
+ // method added, see if it is OK
+ new_flags = (jushort) k_new_method->access_flags().get_flags();
+ if ((new_flags & JVM_ACC_PRIVATE) == 0
+ // hack: private should be treated as final, but alas
+ || (new_flags & (JVM_ACC_FINAL|JVM_ACC_STATIC)) == 0
+ ) {
+ // new methods must be private
+ return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED;
+ }
+ {
+ u2 num = the_class->next_method_idnum();
+ if (num == constMethodOopDesc::UNSET_IDNUM) {
+ // cannot add any more methods
+ return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED;
+ }
+ u2 new_num = k_new_method->method_idnum();
+ methodOop idnum_owner = scratch_class->method_with_idnum(num);
+ if (idnum_owner != NULL) {
+ // There is already a method assigned this idnum -- switch them
+ idnum_owner->set_method_idnum(new_num);
+ }
+ k_new_method->set_method_idnum(num);
+ swap_all_method_annotations(new_num, num, scratch_class);
+ }
+ RC_TRACE(0x00008000, ("Method added: new: %s [%d]",
+ k_new_method->name_and_sig_as_C_string(), ni));
+ ++ni; // advance to next new method
+ break;
+ case deleted:
+ // method deleted, see if it is OK
+ old_flags = (jushort) k_old_method->access_flags().get_flags();
+ if ((old_flags & JVM_ACC_PRIVATE) == 0
+ // hack: private should be treated as final, but alas
+ || (old_flags & (JVM_ACC_FINAL|JVM_ACC_STATIC)) == 0
+ ) {
+ // deleted methods must be private
+ return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_DELETED;
+ }
+ RC_TRACE(0x00008000, ("Method deleted: old: %s [%d]",
+ k_old_method->name_and_sig_as_C_string(), oi));
+ ++oi; // advance to next old method
+ break;
+ default:
+ ShouldNotReachHere();
+ }
+ }
+
+ return JVMTI_ERROR_NONE;
+}
+
+
+// Find new constant pool index value for old constant pool index value
+// by seaching the index map. Returns zero (0) if there is no mapped
+// value for the old constant pool index.
+int VM_RedefineClasses::find_new_index(int old_index) {
+ if (_index_map_count == 0) {
+ // map is empty so nothing can be found
+ return 0;
+ }
+
+ if (old_index < 1 || old_index >= _index_map_p->length()) {
+ // The old_index is out of range so it is not mapped. This should
+ // not happen in regular constant pool merging use, but it can
+ // happen if a corrupt annotation is processed.
+ return 0;
+ }
+
+ int value = _index_map_p->at(old_index);
+ if (value == -1) {
+ // the old_index is not mapped
+ return 0;
+ }
+
+ return value;
+} // end find_new_index()
+
+
+// Returns true if the current mismatch is due to a resolved/unresolved
+// class pair. Otherwise, returns false.
+bool VM_RedefineClasses::is_unresolved_class_mismatch(constantPoolHandle cp1,
+ int index1, constantPoolHandle cp2, int index2) {
+
+ jbyte t1 = cp1->tag_at(index1).value();
+ if (t1 != JVM_CONSTANT_Class && t1 != JVM_CONSTANT_UnresolvedClass) {
+ return false; // wrong entry type; not our special case
+ }
+
+ jbyte t2 = cp2->tag_at(index2).value();
+ if (t2 != JVM_CONSTANT_Class && t2 != JVM_CONSTANT_UnresolvedClass) {
+ return false; // wrong entry type; not our special case
+ }
+
+ if (t1 == t2) {
+ return false; // not a mismatch; not our special case
+ }
+
+ char *s1 = cp1->klass_name_at(index1)->as_C_string();
+ char *s2 = cp2->klass_name_at(index2)->as_C_string();
+ if (strcmp(s1, s2) != 0) {
+ return false; // strings don't match; not our special case
+ }
+
+ return true; // made it through the gauntlet; this is our special case
+} // end is_unresolved_class_mismatch()
+
+
+// Returns true if the current mismatch is due to a resolved/unresolved
+// string pair. Otherwise, returns false.
+bool VM_RedefineClasses::is_unresolved_string_mismatch(constantPoolHandle cp1,
+ int index1, constantPoolHandle cp2, int index2) {
+
+ jbyte t1 = cp1->tag_at(index1).value();
+ if (t1 != JVM_CONSTANT_String && t1 != JVM_CONSTANT_UnresolvedString) {
+ return false; // wrong entry type; not our special case
+ }
+
+ jbyte t2 = cp2->tag_at(index2).value();
+ if (t2 != JVM_CONSTANT_String && t2 != JVM_CONSTANT_UnresolvedString) {
+ return false; // wrong entry type; not our special case
+ }
+
+ if (t1 == t2) {
+ return false; // not a mismatch; not our special case
+ }
+
+ char *s1 = cp1->string_at_noresolve(index1);
+ char *s2 = cp2->string_at_noresolve(index2);
+ if (strcmp(s1, s2) != 0) {
+ return false; // strings don't match; not our special case
+ }
+
+ return true; // made it through the gauntlet; this is our special case
+} // end is_unresolved_string_mismatch()
+
+
+jvmtiError VM_RedefineClasses::load_new_class_versions(TRAPS) {
+ // For consistency allocate memory using os::malloc wrapper.
+ _scratch_classes = (instanceKlassHandle *)
+ os::malloc(sizeof(instanceKlassHandle) * _class_count);
+ if (_scratch_classes == NULL) {
+ return JVMTI_ERROR_OUT_OF_MEMORY;
+ }
+
+ ResourceMark rm(THREAD);
+
+ JvmtiThreadState *state = JvmtiThreadState::state_for(JavaThread::current());
+ for (int i = 0; i < _class_count; i++) {
+ oop mirror = JNIHandles::resolve_non_null(_class_defs[i].klass);
+ // classes for primitives cannot be redefined
+ if (!is_modifiable_class(mirror)) {
+ return JVMTI_ERROR_UNMODIFIABLE_CLASS;
+ }
+ klassOop the_class_oop = java_lang_Class::as_klassOop(mirror);
+ instanceKlassHandle the_class = instanceKlassHandle(THREAD, the_class_oop);
+ symbolHandle the_class_sym = symbolHandle(THREAD, the_class->name());
+
+ // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
+ RC_TRACE_WITH_THREAD(0x00000001, THREAD,
+ ("loading name=%s (avail_mem=" UINT64_FORMAT "K)",
+ the_class->external_name(), os::available_memory() >> 10));
+
+ ClassFileStream st((u1*) _class_defs[i].class_bytes,
+ _class_defs[i].class_byte_count, (char *)"__VM_RedefineClasses__");
+
+ // Parse the stream.
+ Handle the_class_loader(THREAD, the_class->class_loader());
+ Handle protection_domain(THREAD, the_class->protection_domain());
+ // Set redefined class handle in JvmtiThreadState class.
+ // This redefined class is sent to agent event handler for class file
+ // load hook event.
+ state->set_class_being_redefined(&the_class, _class_load_kind);
+
+ klassOop k = SystemDictionary::parse_stream(the_class_sym,
+ the_class_loader,
+ protection_domain,
+ &st,
+ THREAD);
+ // Clear class_being_redefined just to be sure.
+ state->clear_class_being_redefined();
+
+ // TODO: if this is retransform, and nothing changed we can skip it
+
+ instanceKlassHandle scratch_class (THREAD, k);
+
+ if (HAS_PENDING_EXCEPTION) {
+ symbolOop ex_name = PENDING_EXCEPTION->klass()->klass_part()->name();
+ // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
+ RC_TRACE_WITH_THREAD(0x00000002, THREAD, ("parse_stream exception: '%s'",
+ ex_name->as_C_string()));
+ CLEAR_PENDING_EXCEPTION;
+
+ if (ex_name == vmSymbols::java_lang_UnsupportedClassVersionError()) {
+ return JVMTI_ERROR_UNSUPPORTED_VERSION;
+ } else if (ex_name == vmSymbols::java_lang_ClassFormatError()) {
+ return JVMTI_ERROR_INVALID_CLASS_FORMAT;
+ } else if (ex_name == vmSymbols::java_lang_ClassCircularityError()) {
+ return JVMTI_ERROR_CIRCULAR_CLASS_DEFINITION;
+ } else if (ex_name == vmSymbols::java_lang_NoClassDefFoundError()) {
+ // The message will be "XXX (wrong name: YYY)"
+ return JVMTI_ERROR_NAMES_DONT_MATCH;
+ } else if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
+ return JVMTI_ERROR_OUT_OF_MEMORY;
+ } else { // Just in case more exceptions can be thrown..
+ return JVMTI_ERROR_FAILS_VERIFICATION;
+ }
+ }
+
+ // Ensure class is linked before redefine
+ if (!the_class->is_linked()) {
+ the_class->link_class(THREAD);
+ if (HAS_PENDING_EXCEPTION) {
+ symbolOop ex_name = PENDING_EXCEPTION->klass()->klass_part()->name();
+ // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
+ RC_TRACE_WITH_THREAD(0x00000002, THREAD, ("link_class exception: '%s'",
+ ex_name->as_C_string()));
+ CLEAR_PENDING_EXCEPTION;
+ if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
+ return JVMTI_ERROR_OUT_OF_MEMORY;
+ } else {
+ return JVMTI_ERROR_INTERNAL;
+ }
+ }
+ }
+
+ // Do the validity checks in compare_and_normalize_class_versions()
+ // before verifying the byte codes. By doing these checks first, we
+ // limit the number of functions that require redirection from
+ // the_class to scratch_class. In particular, we don't have to
+ // modify JNI GetSuperclass() and thus won't change its performance.
+ jvmtiError res = compare_and_normalize_class_versions(the_class,
+ scratch_class);
+ if (res != JVMTI_ERROR_NONE) {
+ return res;
+ }
+
+ // verify what the caller passed us
+ {
+ // The bug 6214132 caused the verification to fail.
+ // Information about the_class and scratch_class is temporarily
+ // recorded into jvmtiThreadState. This data is used to redirect
+ // the_class to scratch_class in the JVM_* functions called by the
+ // verifier. Please, refer to jvmtiThreadState.hpp for the detailed
+ // description.
+ RedefineVerifyMark rvm(&the_class, &scratch_class, state);
+ Verifier::verify(
+ scratch_class, Verifier::ThrowException, THREAD);
+ }
+
+ if (HAS_PENDING_EXCEPTION) {
+ symbolOop ex_name = PENDING_EXCEPTION->klass()->klass_part()->name();
+ // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
+ RC_TRACE_WITH_THREAD(0x00000002, THREAD,
+ ("verify_byte_codes exception: '%s'", ex_name->as_C_string()));
+ CLEAR_PENDING_EXCEPTION;
+ if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
+ return JVMTI_ERROR_OUT_OF_MEMORY;
+ } else {
+ // tell the caller the bytecodes are bad
+ return JVMTI_ERROR_FAILS_VERIFICATION;
+ }
+ }
+
+ res = merge_cp_and_rewrite(the_class, scratch_class, THREAD);
+ if (res != JVMTI_ERROR_NONE) {
+ return res;
+ }
+
+ if (VerifyMergedCPBytecodes) {
+ // verify what we have done during constant pool merging
+ {
+ RedefineVerifyMark rvm(&the_class, &scratch_class, state);
+ Verifier::verify(scratch_class, Verifier::ThrowException, THREAD);
+ }
+
+ if (HAS_PENDING_EXCEPTION) {
+ symbolOop ex_name = PENDING_EXCEPTION->klass()->klass_part()->name();
+ // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
+ RC_TRACE_WITH_THREAD(0x00000002, THREAD,
+ ("verify_byte_codes post merge-CP exception: '%s'",
+ ex_name->as_C_string()));
+ CLEAR_PENDING_EXCEPTION;
+ if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
+ return JVMTI_ERROR_OUT_OF_MEMORY;
+ } else {
+ // tell the caller that constant pool merging screwed up
+ return JVMTI_ERROR_INTERNAL;
+ }
+ }
+ }
+
+ Rewriter::rewrite(scratch_class, THREAD);
+ if (HAS_PENDING_EXCEPTION) {
+ symbolOop ex_name = PENDING_EXCEPTION->klass()->klass_part()->name();
+ CLEAR_PENDING_EXCEPTION;
+ if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
+ return JVMTI_ERROR_OUT_OF_MEMORY;
+ } else {
+ return JVMTI_ERROR_INTERNAL;
+ }
+ }
+
+ _scratch_classes[i] = scratch_class;
+
+ // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
+ RC_TRACE_WITH_THREAD(0x00000001, THREAD,
+ ("loaded name=%s (avail_mem=" UINT64_FORMAT "K)",
+ the_class->external_name(), os::available_memory() >> 10));
+ }
+
+ return JVMTI_ERROR_NONE;
+}
+
+
+// Map old_index to new_index as needed. scratch_cp is only needed
+// for RC_TRACE() calls.
+void VM_RedefineClasses::map_index(constantPoolHandle scratch_cp,
+ int old_index, int new_index) {
+ if (find_new_index(old_index) != 0) {
+ // old_index is already mapped
+ return;
+ }
+
+ if (old_index == new_index) {
+ // no mapping is needed
+ return;
+ }
+
+ _index_map_p->at_put(old_index, new_index);
+ _index_map_count++;
+
+ RC_TRACE(0x00040000, ("mapped tag %d at index %d to %d",
+ scratch_cp->tag_at(old_index).value(), old_index, new_index));
+} // end map_index()
+
+
+// Merge old_cp and scratch_cp and return the results of the merge via
+// merge_cp_p. The number of entries in *merge_cp_p is returned via
+// merge_cp_length_p. The entries in old_cp occupy the same locations
+// in *merge_cp_p. Also creates a map of indices from entries in
+// scratch_cp to the corresponding entry in *merge_cp_p. Index map
+// entries are only created for entries in scratch_cp that occupy a
+// different location in *merged_cp_p.
+bool VM_RedefineClasses::merge_constant_pools(constantPoolHandle old_cp,
+ constantPoolHandle scratch_cp, constantPoolHandle *merge_cp_p,
+ int *merge_cp_length_p, TRAPS) {
+
+ if (merge_cp_p == NULL) {
+ assert(false, "caller must provide scatch constantPool");
+ return false; // robustness
+ }
+ if (merge_cp_length_p == NULL) {
+ assert(false, "caller must provide scatch CP length");
+ return false; // robustness
+ }
+ // Worst case we need old_cp->length() + scratch_cp()->length(),
+ // but the caller might be smart so make sure we have at least
+ // the minimum.
+ if ((*merge_cp_p)->length() < old_cp->length()) {
+ assert(false, "merge area too small");
+ return false; // robustness
+ }
+
+ RC_TRACE_WITH_THREAD(0x00010000, THREAD,
+ ("old_cp_len=%d, scratch_cp_len=%d", old_cp->length(),
+ scratch_cp->length()));
+
+ {
+ // Pass 0:
+ // The old_cp is copied to *merge_cp_p; this means that any code
+ // using old_cp does not have to change. This work looks like a
+ // perfect fit for constantPoolOop::copy_cp_to(), but we need to
+ // handle one special case:
+ // - revert JVM_CONSTANT_Class to JVM_CONSTANT_UnresolvedClass
+ // This will make verification happy.
+
+ int old_i; // index into old_cp
+
+ // index zero (0) is not used in constantPools
+ for (old_i = 1; old_i < old_cp->length(); old_i++) {
+ // leave debugging crumb
+ jbyte old_tag = old_cp->tag_at(old_i).value();
+ switch (old_tag) {
+ case JVM_CONSTANT_Class:
+ // revert the copy to JVM_CONSTANT_UnresolvedClass
+ (*merge_cp_p)->unresolved_klass_at_put(old_i,
+ old_cp->klass_name_at(old_i));
+ break;
+
+ case JVM_CONSTANT_Double:
+ case JVM_CONSTANT_Long:
+ // just copy the entry to *merge_cp_p, but double and long take
+ // two constant pool entries
+ old_cp->copy_entry_to(old_i, *merge_cp_p, old_i, CHECK_0);
+ old_i++;
+ break;
+
+ default:
+ // just copy the entry to *merge_cp_p
+ old_cp->copy_entry_to(old_i, *merge_cp_p, old_i, CHECK_0);
+ break;
+ }
+ } // end for each old_cp entry
+
+ // We don't need to sanity check that *merge_cp_length_p is within
+ // *merge_cp_p bounds since we have the minimum on-entry check above.
+ (*merge_cp_length_p) = old_i;
+ }
+
+ // merge_cp_len should be the same as old_cp->length() at this point
+ // so this trace message is really a "warm-and-breathing" message.
+ RC_TRACE_WITH_THREAD(0x00020000, THREAD,
+ ("after pass 0: merge_cp_len=%d", *merge_cp_length_p));
+
+ int scratch_i; // index into scratch_cp
+ {
+ // Pass 1a:
+ // Compare scratch_cp entries to the old_cp entries that we have
+ // already copied to *merge_cp_p. In this pass, we are eliminating
+ // exact duplicates (matching entry at same index) so we only
+ // compare entries in the common indice range.
+ int increment = 1;
+ int pass1a_length = MIN2(old_cp->length(), scratch_cp->length());
+ for (scratch_i = 1; scratch_i < pass1a_length; scratch_i += increment) {
+ switch (scratch_cp->tag_at(scratch_i).value()) {
+ case JVM_CONSTANT_Double:
+ case JVM_CONSTANT_Long:
+ // double and long take two constant pool entries
+ increment = 2;
+ break;
+
+ default:
+ increment = 1;
+ break;
+ }
+
+ bool match = scratch_cp->compare_entry_to(scratch_i, *merge_cp_p,
+ scratch_i, CHECK_0);
+ if (match) {
+ // found a match at the same index so nothing more to do
+ continue;
+ } else if (is_unresolved_class_mismatch(scratch_cp, scratch_i,
+ *merge_cp_p, scratch_i)) {
+ // The mismatch in compare_entry_to() above is because of a
+ // resolved versus unresolved class entry at the same index
+ // with the same string value. Since Pass 0 reverted any
+ // class entries to unresolved class entries in *merge_cp_p,
+ // we go with the unresolved class entry.
+ continue;
+ } else if (is_unresolved_string_mismatch(scratch_cp, scratch_i,
+ *merge_cp_p, scratch_i)) {
+ // The mismatch in compare_entry_to() above is because of a
+ // resolved versus unresolved string entry at the same index
+ // with the same string value. We can live with whichever
+ // happens to be at scratch_i in *merge_cp_p.
+ continue;
+ }
+
+ int found_i = scratch_cp->find_matching_entry(scratch_i, *merge_cp_p,
+ CHECK_0);
+ if (found_i != 0) {
+ guarantee(found_i != scratch_i,
+ "compare_entry_to() and find_matching_entry() do not agree");
+
+ // Found a matching entry somewhere else in *merge_cp_p so
+ // just need a mapping entry.
+ map_index(scratch_cp, scratch_i, found_i);
+ continue;
+ }
+
+ // The find_matching_entry() call above could fail to find a match
+ // due to a resolved versus unresolved class or string entry situation
+ // like we solved above with the is_unresolved_*_mismatch() calls.
+ // However, we would have to call is_unresolved_*_mismatch() over
+ // all of *merge_cp_p (potentially) and that doesn't seem to be
+ // worth the time.
+
+ // No match found so we have to append this entry and any unique
+ // referenced entries to *merge_cp_p.
+ append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p,
+ CHECK_0);
+ }
+ }
+
+ RC_TRACE_WITH_THREAD(0x00020000, THREAD,
+ ("after pass 1a: merge_cp_len=%d, scratch_i=%d, index_map_len=%d",
+ *merge_cp_length_p, scratch_i, _index_map_count));
+
+ if (scratch_i < scratch_cp->length()) {
+ // Pass 1b:
+ // old_cp is smaller than scratch_cp so there are entries in
+ // scratch_cp that we have not yet processed. We take care of
+ // those now.
+ int increment = 1;
+ for (; scratch_i < scratch_cp->length(); scratch_i += increment) {
+ switch (scratch_cp->tag_at(scratch_i).value()) {
+ case JVM_CONSTANT_Double:
+ case JVM_CONSTANT_Long:
+ // double and long take two constant pool entries
+ increment = 2;
+ break;
+
+ default:
+ increment = 1;
+ break;
+ }
+
+ int found_i =
+ scratch_cp->find_matching_entry(scratch_i, *merge_cp_p, CHECK_0);
+ if (found_i != 0) {
+ // Found a matching entry somewhere else in *merge_cp_p so
+ // just need a mapping entry.
+ map_index(scratch_cp, scratch_i, found_i);
+ continue;
+ }
+
+ // No match found so we have to append this entry and any unique
+ // referenced entries to *merge_cp_p.
+ append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p,
+ CHECK_0);
+ }
+
+ RC_TRACE_WITH_THREAD(0x00020000, THREAD,
+ ("after pass 1b: merge_cp_len=%d, scratch_i=%d, index_map_len=%d",
+ *merge_cp_length_p, scratch_i, _index_map_count));
+ }
+
+ return true;
+} // end merge_constant_pools()
+
+
+// Merge constant pools between the_class and scratch_class and
+// potentially rewrite bytecodes in scratch_class to use the merged
+// constant pool.
+jvmtiError VM_RedefineClasses::merge_cp_and_rewrite(
+ instanceKlassHandle the_class, instanceKlassHandle scratch_class,
+ TRAPS) {
+ // worst case merged constant pool length is old and new combined
+ int merge_cp_length = the_class->constants()->length()
+ + scratch_class->constants()->length();
+
+ constantPoolHandle old_cp(THREAD, the_class->constants());
+ constantPoolHandle scratch_cp(THREAD, scratch_class->constants());
+
+ // Constant pools are not easily reused so we allocate a new one
+ // each time.
+ constantPoolHandle merge_cp(THREAD,
+ oopFactory::new_constantPool(merge_cp_length, THREAD));
+ int orig_length = old_cp->orig_length();
+ if (orig_length == 0) {
+ // This old_cp is an actual original constant pool. We save
+ // the original length in the merged constant pool so that
+ // merge_constant_pools() can be more efficient. If a constant
+ // pool has a non-zero orig_length() value, then that constant
+ // pool was created by a merge operation in RedefineClasses.
+ merge_cp->set_orig_length(old_cp->length());
+ } else {
+ // This old_cp is a merged constant pool from a previous
+ // RedefineClasses() calls so just copy the orig_length()
+ // value.
+ merge_cp->set_orig_length(old_cp->orig_length());
+ }
+
+ ResourceMark rm(THREAD);
+ _index_map_count = 0;
+ _index_map_p = new intArray(scratch_cp->length(), -1);
+
+ bool result = merge_constant_pools(old_cp, scratch_cp, &merge_cp,
+ &merge_cp_length, THREAD);
+ if (!result) {
+ // The merge can fail due to memory allocation failure or due
+ // to robustness checks.
+ return JVMTI_ERROR_INTERNAL;
+ }
+
+ RC_TRACE_WITH_THREAD(0x00010000, THREAD,
+ ("merge_cp_len=%d, index_map_len=%d", merge_cp_length, _index_map_count));
+
+ if (_index_map_count == 0) {
+ // there is nothing to map between the new and merged constant pools
+
+ if (old_cp->length() == scratch_cp->length()) {
+ // The old and new constant pools are the same length and the
+ // index map is empty. This means that the three constant pools
+ // are equivalent (but not the same). Unfortunately, the new
+ // constant pool has not gone through link resolution nor have
+ // the new class bytecodes gone through constant pool cache
+ // rewriting so we can't use the old constant pool with the new
+ // class.
+
+ merge_cp = constantPoolHandle(); // toss the merged constant pool
+ } else if (old_cp->length() < scratch_cp->length()) {
+ // The old constant pool has fewer entries than the new constant
+ // pool and the index map is empty. This means the new constant
+ // pool is a superset of the old constant pool. However, the old
+ // class bytecodes have already gone through constant pool cache
+ // rewriting so we can't use the new constant pool with the old
+ // class.
+
+ merge_cp = constantPoolHandle(); // toss the merged constant pool
+ } else {
+ // The old constant pool has more entries than the new constant
+ // pool and the index map is empty. This means that both the old
+ // and merged constant pools are supersets of the new constant
+ // pool.
+
+ // Replace the new constant pool with a shrunken copy of the
+ // merged constant pool; the previous new constant pool will
+ // get GCed.
+ set_new_constant_pool(scratch_class, merge_cp, merge_cp_length, true,
+ THREAD);
+ // drop local ref to the merged constant pool
+ merge_cp = constantPoolHandle();
+ }
+ } else {
+ if (RC_TRACE_ENABLED(0x00040000)) {
+ // don't want to loop unless we are tracing
+ int count = 0;
+ for (int i = 1; i < _index_map_p->length(); i++) {
+ int value = _index_map_p->at(i);
+
+ if (value != -1) {
+ RC_TRACE_WITH_THREAD(0x00040000, THREAD,
+ ("index_map[%d]: old=%d new=%d", count, i, value));
+ count++;
+ }
+ }
+ }
+
+ // We have entries mapped between the new and merged constant pools
+ // so we have to rewrite some constant pool references.
+ if (!rewrite_cp_refs(scratch_class, THREAD)) {
+ return JVMTI_ERROR_INTERNAL;
+ }
+
+ // Replace the new constant pool with a shrunken copy of the
+ // merged constant pool so now the rewritten bytecodes have
+ // valid references; the previous new constant pool will get
+ // GCed.
+ set_new_constant_pool(scratch_class, merge_cp, merge_cp_length, true,
+ THREAD);
+ }
+
+ return JVMTI_ERROR_NONE;
+} // end merge_cp_and_rewrite()
+
+
+// Rewrite constant pool references in klass scratch_class.
+bool VM_RedefineClasses::rewrite_cp_refs(instanceKlassHandle scratch_class,
+ TRAPS) {
+
+ // rewrite constant pool references in the methods:
+ if (!rewrite_cp_refs_in_methods(scratch_class, THREAD)) {
+ // propogate failure back to caller
+ return false;
+ }
+
+ // rewrite constant pool references in the class_annotations:
+ if (!rewrite_cp_refs_in_class_annotations(scratch_class, THREAD)) {
+ // propogate failure back to caller
+ return false;
+ }
+
+ // rewrite constant pool references in the fields_annotations:
+ if (!rewrite_cp_refs_in_fields_annotations(scratch_class, THREAD)) {
+ // propogate failure back to caller
+ return false;
+ }
+
+ // rewrite constant pool references in the methods_annotations:
+ if (!rewrite_cp_refs_in_methods_annotations(scratch_class, THREAD)) {
+ // propogate failure back to caller
+ return false;
+ }
+
+ // rewrite constant pool references in the methods_parameter_annotations:
+ if (!rewrite_cp_refs_in_methods_parameter_annotations(scratch_class,
+ THREAD)) {
+ // propogate failure back to caller
+ return false;
+ }
+
+ // rewrite constant pool references in the methods_default_annotations:
+ if (!rewrite_cp_refs_in_methods_default_annotations(scratch_class,
+ THREAD)) {
+ // propogate failure back to caller
+ return false;
+ }
+
+ return true;
+} // end rewrite_cp_refs()
+
+
+// Rewrite constant pool references in the methods.
+bool VM_RedefineClasses::rewrite_cp_refs_in_methods(
+ instanceKlassHandle scratch_class, TRAPS) {
+
+ objArrayHandle methods(THREAD, scratch_class->methods());
+
+ if (methods.is_null() || methods->length() == 0) {
+ // no methods so nothing to do
+ return true;
+ }
+
+ // rewrite constant pool references in the methods:
+ for (int i = methods->length() - 1; i >= 0; i--) {
+ methodHandle method(THREAD, (methodOop)methods->obj_at(i));
+ methodHandle new_method;
+ rewrite_cp_refs_in_method(method, &new_method, CHECK_false);
+ if (!new_method.is_null()) {
+ // the method has been replaced so save the new method version
+ methods->obj_at_put(i, new_method());
+ }
+ }
+
+ return true;
+}
+
+
+// Rewrite constant pool references in the specific method. This code
+// was adapted from Rewriter::rewrite_method().
+void VM_RedefineClasses::rewrite_cp_refs_in_method(methodHandle method,
+ methodHandle *new_method_p, TRAPS) {
+
+ *new_method_p = methodHandle(); // default is no new method
+
+ // We cache a pointer to the bytecodes here in code_base. If GC
+ // moves the methodOop, then the bytecodes will also move which
+ // will likely cause a crash. We create a No_Safepoint_Verifier
+ // object to detect whether we pass a possible safepoint in this
+ // code block.
+ No_Safepoint_Verifier nsv;
+
+ // Bytecodes and their length
+ address code_base = method->code_base();
+ int code_length = method->code_size();
+
+ int bc_length;
+ for (int bci = 0; bci < code_length; bci += bc_length) {
+ address bcp = code_base + bci;
+ Bytecodes::Code c = (Bytecodes::Code)(*bcp);
+
+ bc_length = Bytecodes::length_for(c);
+ if (bc_length == 0) {
+ // More complicated bytecodes report a length of zero so
+ // we have to try again a slightly different way.
+ bc_length = Bytecodes::length_at(bcp);
+ }
+
+ assert(bc_length != 0, "impossible bytecode length");
+
+ switch (c) {
+ case Bytecodes::_ldc:
+ {
+ int cp_index = *(bcp + 1);
+ int new_index = find_new_index(cp_index);
+
+ if (StressLdcRewrite && new_index == 0) {
+ // If we are stressing ldc -> ldc_w rewriting, then we
+ // always need a new_index value.
+ new_index = cp_index;
+ }
+ if (new_index != 0) {
+ // the original index is mapped so we have more work to do
+ if (!StressLdcRewrite && new_index <= max_jubyte) {
+ // The new value can still use ldc instead of ldc_w
+ // unless we are trying to stress ldc -> ldc_w rewriting
+ RC_TRACE_WITH_THREAD(0x00080000, THREAD,
+ ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c),
+ bcp, cp_index, new_index));
+ *(bcp + 1) = new_index;
+ } else {
+ RC_TRACE_WITH_THREAD(0x00080000, THREAD,
+ ("%s->ldc_w@" INTPTR_FORMAT " old=%d, new=%d",
+ Bytecodes::name(c), bcp, cp_index, new_index));
+ // the new value needs ldc_w instead of ldc
+ u_char inst_buffer[4]; // max instruction size is 4 bytes
+ bcp = (address)inst_buffer;
+ // construct new instruction sequence
+ *bcp = Bytecodes::_ldc_w;
+ bcp++;
+ // Rewriter::rewrite_method() does not rewrite ldc -> ldc_w.
+ // See comment below for difference between put_Java_u2()
+ // and put_native_u2().
+ Bytes::put_Java_u2(bcp, new_index);
+
+ Relocator rc(method, NULL /* no RelocatorListener needed */);
+ methodHandle m;
+ {
+ Pause_No_Safepoint_Verifier pnsv(&nsv);
+
+ // ldc is 2 bytes and ldc_w is 3 bytes
+ m = rc.insert_space_at(bci, 3, inst_buffer, THREAD);
+ if (m.is_null() || HAS_PENDING_EXCEPTION) {
+ guarantee(false, "insert_space_at() failed");
+ }
+ }
+
+ // return the new method so that the caller can update
+ // the containing class
+ *new_method_p = method = m;
+ // switch our bytecode processing loop from the old method
+ // to the new method
+ code_base = method->code_base();
+ code_length = method->code_size();
+ bcp = code_base + bci;
+ c = (Bytecodes::Code)(*bcp);
+ bc_length = Bytecodes::length_for(c);
+ assert(bc_length != 0, "sanity check");
+ } // end we need ldc_w instead of ldc
+ } // end if there is a mapped index
+ } break;
+
+ // these bytecodes have a two-byte constant pool index
+ case Bytecodes::_anewarray : // fall through
+ case Bytecodes::_checkcast : // fall through
+ case Bytecodes::_getfield : // fall through
+ case Bytecodes::_getstatic : // fall through
+ case Bytecodes::_instanceof : // fall through
+ case Bytecodes::_invokeinterface: // fall through
+ case Bytecodes::_invokespecial : // fall through
+ case Bytecodes::_invokestatic : // fall through
+ case Bytecodes::_invokevirtual : // fall through
+ case Bytecodes::_ldc_w : // fall through
+ case Bytecodes::_ldc2_w : // fall through
+ case Bytecodes::_multianewarray : // fall through
+ case Bytecodes::_new : // fall through
+ case Bytecodes::_putfield : // fall through
+ case Bytecodes::_putstatic :
+ {
+ address p = bcp + 1;
+ int cp_index = Bytes::get_Java_u2(p);
+ int new_index = find_new_index(cp_index);
+ if (new_index != 0) {
+ // the original index is mapped so update w/ new value
+ RC_TRACE_WITH_THREAD(0x00080000, THREAD,
+ ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c),
+ bcp, cp_index, new_index));
+ // Rewriter::rewrite_method() uses put_native_u2() in this
+ // situation because it is reusing the constant pool index
+ // location for a native index into the constantPoolCache.
+ // Since we are updating the constant pool index prior to
+ // verification and constantPoolCache initialization, we
+ // need to keep the new index in Java byte order.
+ Bytes::put_Java_u2(p, new_index);
+ }
+ } break;
+ }
+ } // end for each bytecode
+} // end rewrite_cp_refs_in_method()
+
+
+// Rewrite constant pool references in the class_annotations field.
+bool VM_RedefineClasses::rewrite_cp_refs_in_class_annotations(
+ instanceKlassHandle scratch_class, TRAPS) {
+
+ typeArrayHandle class_annotations(THREAD,
+ scratch_class->class_annotations());
+ if (class_annotations.is_null() || class_annotations->length() == 0) {
+ // no class_annotations so nothing to do
+ return true;
+ }
+
+ RC_TRACE_WITH_THREAD(0x02000000, THREAD,
+ ("class_annotations length=%d", class_annotations->length()));
+
+ int byte_i = 0; // byte index into class_annotations
+ return rewrite_cp_refs_in_annotations_typeArray(class_annotations, byte_i,
+ THREAD);
+}
+
+
+// Rewrite constant pool references in an annotations typeArray. This
+// "structure" is adapted from the RuntimeVisibleAnnotations_attribute
+// that is described in section 4.8.15 of the 2nd-edition of the VM spec:
+//
+// annotations_typeArray {
+// u2 num_annotations;
+// annotation annotations[num_annotations];
+// }
+//
+bool VM_RedefineClasses::rewrite_cp_refs_in_annotations_typeArray(
+ typeArrayHandle annotations_typeArray, int &byte_i_ref, TRAPS) {
+
+ if ((byte_i_ref + 2) > annotations_typeArray->length()) {
+ // not enough room for num_annotations field
+ RC_TRACE_WITH_THREAD(0x02000000, THREAD,
+ ("length() is too small for num_annotations field"));
+ return false;
+ }
+
+ u2 num_annotations = Bytes::get_Java_u2((address)
+ annotations_typeArray->byte_at_addr(byte_i_ref));
+ byte_i_ref += 2;
+
+ RC_TRACE_WITH_THREAD(0x02000000, THREAD,
+ ("num_annotations=%d", num_annotations));
+
+ int calc_num_annotations = 0;
+ for (; calc_num_annotations < num_annotations; calc_num_annotations++) {
+ if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray,
+ byte_i_ref, THREAD)) {
+ RC_TRACE_WITH_THREAD(0x02000000, THREAD,
+ ("bad annotation_struct at %d", calc_num_annotations));
+ // propogate failure back to caller
+ return false;
+ }
+ }
+ assert(num_annotations == calc_num_annotations, "sanity check");
+
+ return true;
+} // end rewrite_cp_refs_in_annotations_typeArray()
+
+
+// Rewrite constant pool references in the annotation struct portion of
+// an annotations_typeArray. This "structure" is from section 4.8.15 of
+// the 2nd-edition of the VM spec:
+//
+// struct annotation {
+// u2 type_index;
+// u2 num_element_value_pairs;
+// {
+// u2 element_name_index;
+// element_value value;
+// } element_value_pairs[num_element_value_pairs];
+// }
+//
+bool VM_RedefineClasses::rewrite_cp_refs_in_annotation_struct(
+ typeArrayHandle annotations_typeArray, int &byte_i_ref, TRAPS) {
+ if ((byte_i_ref + 2 + 2) > annotations_typeArray->length()) {
+ // not enough room for smallest annotation_struct
+ RC_TRACE_WITH_THREAD(0x02000000, THREAD,
+ ("length() is too small for annotation_struct"));
+ return false;
+ }
+
+ u2 type_index = rewrite_cp_ref_in_annotation_data(annotations_typeArray,
+ byte_i_ref, "mapped old type_index=%d", THREAD);
+
+ u2 num_element_value_pairs = Bytes::get_Java_u2((address)
+ annotations_typeArray->byte_at_addr(
+ byte_i_ref));
+ byte_i_ref += 2;
+
+ RC_TRACE_WITH_THREAD(0x02000000, THREAD,
+ ("type_index=%d num_element_value_pairs=%d", type_index,
+ num_element_value_pairs));
+
+ int calc_num_element_value_pairs = 0;
+ for (; calc_num_element_value_pairs < num_element_value_pairs;
+ calc_num_element_value_pairs++) {
+ if ((byte_i_ref + 2) > annotations_typeArray->length()) {
+ // not enough room for another element_name_index, let alone
+ // the rest of another component
+ RC_TRACE_WITH_THREAD(0x02000000, THREAD,
+ ("length() is too small for element_name_index"));
+ return false;
+ }
+
+ u2 element_name_index = rewrite_cp_ref_in_annotation_data(
+ annotations_typeArray, byte_i_ref,
+ "mapped old element_name_index=%d", THREAD);
+
+ RC_TRACE_WITH_THREAD(0x02000000, THREAD,
+ ("element_name_index=%d", element_name_index));
+
+ if (!rewrite_cp_refs_in_element_value(annotations_typeArray,
+ byte_i_ref, THREAD)) {
+ RC_TRACE_WITH_THREAD(0x02000000, THREAD,
+ ("bad element_value at %d", calc_num_element_value_pairs));
+ // propogate failure back to caller
+ return false;
+ }
+ } // end for each component
+ assert(num_element_value_pairs == calc_num_element_value_pairs,
+ "sanity check");
+
+ return true;
+} // end rewrite_cp_refs_in_annotation_struct()
+
+
+// Rewrite a constant pool reference at the current position in
+// annotations_typeArray if needed. Returns the original constant
+// pool reference if a rewrite was not needed or the new constant
+// pool reference if a rewrite was needed.
+u2 VM_RedefineClasses::rewrite_cp_ref_in_annotation_data(
+ typeArrayHandle annotations_typeArray, int &byte_i_ref,
+ const char * trace_mesg, TRAPS) {
+
+ address cp_index_addr = (address)
+ annotations_typeArray->byte_at_addr(byte_i_ref);
+ u2 old_cp_index = Bytes::get_Java_u2(cp_index_addr);
+ u2 new_cp_index = find_new_index(old_cp_index);
+ if (new_cp_index != 0) {
+ RC_TRACE_WITH_THREAD(0x02000000, THREAD, (trace_mesg, old_cp_index));
+ Bytes::put_Java_u2(cp_index_addr, new_cp_index);
+ old_cp_index = new_cp_index;
+ }
+ byte_i_ref += 2;
+ return old_cp_index;
+}
+
+
+// Rewrite constant pool references in the element_value portion of an
+// annotations_typeArray. This "structure" is from section 4.8.15.1 of
+// the 2nd-edition of the VM spec:
+//
+// struct element_value {
+// u1 tag;
+// union {
+// u2 const_value_index;
+// {
+// u2 type_name_index;
+// u2 const_name_index;
+// } enum_const_value;
+// u2 class_info_index;
+// annotation annotation_value;
+// struct {
+// u2 num_values;
+// element_value values[num_values];
+// } array_value;
+// } value;
+// }
+//
+bool VM_RedefineClasses::rewrite_cp_refs_in_element_value(
+ typeArrayHandle annotations_typeArray, int &byte_i_ref, TRAPS) {
+
+ if ((byte_i_ref + 1) > annotations_typeArray->length()) {
+ // not enough room for a tag let alone the rest of an element_value
+ RC_TRACE_WITH_THREAD(0x02000000, THREAD,
+ ("length() is too small for a tag"));
+ return false;
+ }
+
+ u1 tag = annotations_typeArray->byte_at(byte_i_ref);
+ byte_i_ref++;
+ RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("tag='%c'", tag));
+
+ switch (tag) {
+ // These BaseType tag values are from Table 4.2 in VM spec:
+ case 'B': // byte
+ case 'C': // char
+ case 'D': // double
+ case 'F': // float
+ case 'I': // int
+ case 'J': // long
+ case 'S': // short
+ case 'Z': // boolean
+
+ // The remaining tag values are from Table 4.8 in the 2nd-edition of
+ // the VM spec:
+ case 's':
+ {
+ // For the above tag values (including the BaseType values),
+ // value.const_value_index is right union field.
+
+ if ((byte_i_ref + 2) > annotations_typeArray->length()) {
+ // not enough room for a const_value_index
+ RC_TRACE_WITH_THREAD(0x02000000, THREAD,
+ ("length() is too small for a const_value_index"));
+ return false;
+ }
+
+ u2 const_value_index = rewrite_cp_ref_in_annotation_data(
+ annotations_typeArray, byte_i_ref,
+ "mapped old const_value_index=%d", THREAD);
+
+ RC_TRACE_WITH_THREAD(0x02000000, THREAD,
+ ("const_value_index=%d", const_value_index));
+ } break;
+
+ case 'e':
+ {
+ // for the above tag value, value.enum_const_value is right union field
+
+ if ((byte_i_ref + 4) > annotations_typeArray->length()) {
+ // not enough room for a enum_const_value
+ RC_TRACE_WITH_THREAD(0x02000000, THREAD,
+ ("length() is too small for a enum_const_value"));
+ return false;
+ }
+
+ u2 type_name_index = rewrite_cp_ref_in_annotation_data(
+ annotations_typeArray, byte_i_ref,
+ "mapped old type_name_index=%d", THREAD);
+
+ u2 const_name_index = rewrite_cp_ref_in_annotation_data(
+ annotations_typeArray, byte_i_ref,
+ "mapped old const_name_index=%d", THREAD);
+
+ RC_TRACE_WITH_THREAD(0x02000000, THREAD,
+ ("type_name_index=%d const_name_index=%d", type_name_index,
+ const_name_index));
+ } break;
+
+ case 'c':
+ {
+ // for the above tag value, value.class_info_index is right union field
+
+ if ((byte_i_ref + 2) > annotations_typeArray->length()) {
+ // not enough room for a class_info_index
+ RC_TRACE_WITH_THREAD(0x02000000, THREAD,
+ ("length() is too small for a class_info_index"));
+ return false;
+ }
+
+ u2 class_info_index = rewrite_cp_ref_in_annotation_data(
+ annotations_typeArray, byte_i_ref,
+ "mapped old class_info_index=%d", THREAD);
+
+ RC_TRACE_WITH_THREAD(0x02000000, THREAD,
+ ("class_info_index=%d", class_info_index));
+ } break;
+
+ case '@':
+ // For the above tag value, value.attr_value is the right union
+ // field. This is a nested annotation.
+ if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray,
+ byte_i_ref, THREAD)) {
+ // propogate failure back to caller
+ return false;
+ }
+ break;
+
+ case '[':
+ {
+ if ((byte_i_ref + 2) > annotations_typeArray->length()) {
+ // not enough room for a num_values field
+ RC_TRACE_WITH_THREAD(0x02000000, THREAD,
+ ("length() is too small for a num_values field"));
+ return false;
+ }
+
+ // For the above tag value, value.array_value is the right union
+ // field. This is an array of nested element_value.
+ u2 num_values = Bytes::get_Java_u2((address)
+ annotations_typeArray->byte_at_addr(byte_i_ref));
+ byte_i_ref += 2;
+ RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("num_values=%d", num_values));
+
+ int calc_num_values = 0;
+ for (; calc_num_values < num_values; calc_num_values++) {
+ if (!rewrite_cp_refs_in_element_value(
+ annotations_typeArray, byte_i_ref, THREAD)) {
+ RC_TRACE_WITH_THREAD(0x02000000, THREAD,
+ ("bad nested element_value at %d", calc_num_values));
+ // propogate failure back to caller
+ return false;
+ }
+ }
+ assert(num_values == calc_num_values, "sanity check");
+ } break;
+
+ default:
+ RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("bad tag=0x%x", tag));
+ return false;
+ } // end decode tag field
+
+ return true;
+} // end rewrite_cp_refs_in_element_value()
+
+
+// Rewrite constant pool references in a fields_annotations field.
+bool VM_RedefineClasses::rewrite_cp_refs_in_fields_annotations(
+ instanceKlassHandle scratch_class, TRAPS) {
+
+ objArrayHandle fields_annotations(THREAD,
+ scratch_class->fields_annotations());
+
+ if (fields_annotations.is_null() || fields_annotations->length() == 0) {
+ // no fields_annotations so nothing to do
+ return true;
+ }
+
+ RC_TRACE_WITH_THREAD(0x02000000, THREAD,
+ ("fields_annotations length=%d", fields_annotations->length()));
+
+ for (int i = 0; i < fields_annotations->length(); i++) {
+ typeArrayHandle field_annotations(THREAD,
+ (typeArrayOop)fields_annotations->obj_at(i));
+ if (field_annotations.is_null() || field_annotations->length() == 0) {
+ // this field does not have any annotations so skip it
+ continue;
+ }
+
+ int byte_i = 0; // byte index into field_annotations
+ if (!rewrite_cp_refs_in_annotations_typeArray(field_annotations, byte_i,
+ THREAD)) {
+ RC_TRACE_WITH_THREAD(0x02000000, THREAD,
+ ("bad field_annotations at %d", i));
+ // propogate failure back to caller
+ return false;
+ }
+ }
+
+ return true;
+} // end rewrite_cp_refs_in_fields_annotations()
+
+
+// Rewrite constant pool references in a methods_annotations field.
+bool VM_RedefineClasses::rewrite_cp_refs_in_methods_annotations(
+ instanceKlassHandle scratch_class, TRAPS) {
+
+ objArrayHandle methods_annotations(THREAD,
+ scratch_class->methods_annotations());
+
+ if (methods_annotations.is_null() || methods_annotations->length() == 0) {
+ // no methods_annotations so nothing to do
+ return true;
+ }
+
+ RC_TRACE_WITH_THREAD(0x02000000, THREAD,
+ ("methods_annotations length=%d", methods_annotations->length()));
+
+ for (int i = 0; i < methods_annotations->length(); i++) {
+ typeArrayHandle method_annotations(THREAD,
+ (typeArrayOop)methods_annotations->obj_at(i));
+ if (method_annotations.is_null() || method_annotations->length() == 0) {
+ // this method does not have any annotations so skip it
+ continue;
+ }
+
+ int byte_i = 0; // byte index into method_annotations
+ if (!rewrite_cp_refs_in_annotations_typeArray(method_annotations, byte_i,
+ THREAD)) {
+ RC_TRACE_WITH_THREAD(0x02000000, THREAD,
+ ("bad method_annotations at %d", i));
+ // propogate failure back to caller
+ return false;
+ }
+ }
+
+ return true;
+} // end rewrite_cp_refs_in_methods_annotations()
+
+
+// Rewrite constant pool references in a methods_parameter_annotations
+// field. This "structure" is adapted from the
+// RuntimeVisibleParameterAnnotations_attribute described in section
+// 4.8.17 of the 2nd-edition of the VM spec:
+//
+// methods_parameter_annotations_typeArray {
+// u1 num_parameters;
+// {
+// u2 num_annotations;
+// annotation annotations[num_annotations];
+// } parameter_annotations[num_parameters];
+// }
+//
+bool VM_RedefineClasses::rewrite_cp_refs_in_methods_parameter_annotations(
+ instanceKlassHandle scratch_class, TRAPS) {
+
+ objArrayHandle methods_parameter_annotations(THREAD,
+ scratch_class->methods_parameter_annotations());
+
+ if (methods_parameter_annotations.is_null()
+ || methods_parameter_annotations->length() == 0) {
+ // no methods_parameter_annotations so nothing to do
+ return true;
+ }
+
+ RC_TRACE_WITH_THREAD(0x02000000, THREAD,
+ ("methods_parameter_annotations length=%d",
+ methods_parameter_annotations->length()));
+
+ for (int i = 0; i < methods_parameter_annotations->length(); i++) {
+ typeArrayHandle method_parameter_annotations(THREAD,
+ (typeArrayOop)methods_parameter_annotations->obj_at(i));
+ if (method_parameter_annotations.is_null()
+ || method_parameter_annotations->length() == 0) {
+ // this method does not have any parameter annotations so skip it
+ continue;
+ }
+
+ if (method_parameter_annotations->length() < 1) {
+ // not enough room for a num_parameters field
+ RC_TRACE_WITH_THREAD(0x02000000, THREAD,
+ ("length() is too small for a num_parameters field at %d", i));
+ return false;
+ }
+
+ int byte_i = 0; // byte index into method_parameter_annotations
+
+ u1 num_parameters = method_parameter_annotations->byte_at(byte_i);
+ byte_i++;
+
+ RC_TRACE_WITH_THREAD(0x02000000, THREAD,
+ ("num_parameters=%d", num_parameters));
+
+ int calc_num_parameters = 0;
+ for (; calc_num_parameters < num_parameters; calc_num_parameters++) {
+ if (!rewrite_cp_refs_in_annotations_typeArray(
+ method_parameter_annotations, byte_i, THREAD)) {
+ RC_TRACE_WITH_THREAD(0x02000000, THREAD,
+ ("bad method_parameter_annotations at %d", calc_num_parameters));
+ // propogate failure back to caller
+ return false;
+ }
+ }
+ assert(num_parameters == calc_num_parameters, "sanity check");
+ }
+
+ return true;
+} // end rewrite_cp_refs_in_methods_parameter_annotations()
+
+
+// Rewrite constant pool references in a methods_default_annotations
+// field. This "structure" is adapted from the AnnotationDefault_attribute
+// that is described in section 4.8.19 of the 2nd-edition of the VM spec:
+//
+// methods_default_annotations_typeArray {
+// element_value default_value;
+// }
+//
+bool VM_RedefineClasses::rewrite_cp_refs_in_methods_default_annotations(
+ instanceKlassHandle scratch_class, TRAPS) {
+
+ objArrayHandle methods_default_annotations(THREAD,
+ scratch_class->methods_default_annotations());
+
+ if (methods_default_annotations.is_null()
+ || methods_default_annotations->length() == 0) {
+ // no methods_default_annotations so nothing to do
+ return true;
+ }
+
+ RC_TRACE_WITH_THREAD(0x02000000, THREAD,
+ ("methods_default_annotations length=%d",
+ methods_default_annotations->length()));
+
+ for (int i = 0; i < methods_default_annotations->length(); i++) {
+ typeArrayHandle method_default_annotations(THREAD,
+ (typeArrayOop)methods_default_annotations->obj_at(i));
+ if (method_default_annotations.is_null()
+ || method_default_annotations->length() == 0) {
+ // this method does not have any default annotations so skip it
+ continue;
+ }
+
+ int byte_i = 0; // byte index into method_default_annotations
+
+ if (!rewrite_cp_refs_in_element_value(
+ method_default_annotations, byte_i, THREAD)) {
+ RC_TRACE_WITH_THREAD(0x02000000, THREAD,
+ ("bad default element_value at %d", i));
+ // propogate failure back to caller
+ return false;
+ }
+ }
+
+ return true;
+} // end rewrite_cp_refs_in_methods_default_annotations()
+
+
+// Rewrite constant pool references in the method's stackmap table.
+// These "structures" are adapted from the StackMapTable_attribute that
+// is described in section 4.8.4 of the 6.0 version of the VM spec
+// (dated 2005.10.26):
+// file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf
+//
+// stack_map {
+// u2 number_of_entries;
+// stack_map_frame entries[number_of_entries];
+// }
+//
+void VM_RedefineClasses::rewrite_cp_refs_in_stack_map_table(
+ methodHandle method, TRAPS) {
+
+ if (!method->has_stackmap_table()) {
+ return;
+ }
+
+ typeArrayOop stackmap_data = method->stackmap_data();
+ address stackmap_p = (address)stackmap_data->byte_at_addr(0);
+ address stackmap_end = stackmap_p + stackmap_data->length();
+
+ assert(stackmap_p + 2 <= stackmap_end, "no room for number_of_entries");
+ u2 number_of_entries = Bytes::get_Java_u2(stackmap_p);
+ stackmap_p += 2;
+
+ RC_TRACE_WITH_THREAD(0x04000000, THREAD,
+ ("number_of_entries=%u", number_of_entries));
+
+ // walk through each stack_map_frame
+ u2 calc_number_of_entries = 0;
+ for (; calc_number_of_entries < number_of_entries; calc_number_of_entries++) {
+ // The stack_map_frame structure is a u1 frame_type followed by
+ // 0 or more bytes of data:
+ //
+ // union stack_map_frame {
+ // same_frame;
+ // same_locals_1_stack_item_frame;
+ // same_locals_1_stack_item_frame_extended;
+ // chop_frame;
+ // same_frame_extended;
+ // append_frame;
+ // full_frame;
+ // }
+
+ assert(stackmap_p + 1 <= stackmap_end, "no room for frame_type");
+ // The Linux compiler does not like frame_type to be u1 or u2. It
+ // issues the following warning for the first if-statement below:
+ //
+ // "warning: comparison is always true due to limited range of data type"
+ //
+ u4 frame_type = *stackmap_p;
+ stackmap_p++;
+
+ // same_frame {
+ // u1 frame_type = SAME; /* 0-63 */
+ // }
+ if (frame_type >= 0 && frame_type <= 63) {
+ // nothing more to do for same_frame
+ }
+
+ // same_locals_1_stack_item_frame {
+ // u1 frame_type = SAME_LOCALS_1_STACK_ITEM; /* 64-127 */
+ // verification_type_info stack[1];
+ // }
+ else if (frame_type >= 64 && frame_type <= 127) {
+ rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
+ calc_number_of_entries, frame_type, THREAD);
+ }
+
+ // reserved for future use
+ else if (frame_type >= 128 && frame_type <= 246) {
+ // nothing more to do for reserved frame_types
+ }
+
+ // same_locals_1_stack_item_frame_extended {
+ // u1 frame_type = SAME_LOCALS_1_STACK_ITEM_EXTENDED; /* 247 */
+ // u2 offset_delta;
+ // verification_type_info stack[1];
+ // }
+ else if (frame_type == 247) {
+ stackmap_p += 2;
+ rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
+ calc_number_of_entries, frame_type, THREAD);
+ }
+
+ // chop_frame {
+ // u1 frame_type = CHOP; /* 248-250 */
+ // u2 offset_delta;
+ // }
+ else if (frame_type >= 248 && frame_type <= 250) {
+ stackmap_p += 2;
+ }
+
+ // same_frame_extended {
+ // u1 frame_type = SAME_FRAME_EXTENDED; /* 251*/
+ // u2 offset_delta;
+ // }
+ else if (frame_type == 251) {
+ stackmap_p += 2;
+ }
+
+ // append_frame {
+ // u1 frame_type = APPEND; /* 252-254 */
+ // u2 offset_delta;
+ // verification_type_info locals[frame_type - 251];
+ // }
+ else if (frame_type >= 252 && frame_type <= 254) {
+ assert(stackmap_p + 2 <= stackmap_end,
+ "no room for offset_delta");
+ stackmap_p += 2;
+ u1 len = frame_type - 251;
+ for (u1 i = 0; i < len; i++) {
+ rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
+ calc_number_of_entries, frame_type, THREAD);
+ }
+ }
+
+ // full_frame {
+ // u1 frame_type = FULL_FRAME; /* 255 */
+ // u2 offset_delta;
+ // u2 number_of_locals;
+ // verification_type_info locals[number_of_locals];
+ // u2 number_of_stack_items;
+ // verification_type_info stack[number_of_stack_items];
+ // }
+ else if (frame_type == 255) {
+ assert(stackmap_p + 2 + 2 <= stackmap_end,
+ "no room for smallest full_frame");
+ stackmap_p += 2;
+
+ u2 number_of_locals = Bytes::get_Java_u2(stackmap_p);
+ stackmap_p += 2;
+
+ for (u2 locals_i = 0; locals_i < number_of_locals; locals_i++) {
+ rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
+ calc_number_of_entries, frame_type, THREAD);
+ }
+
+ // Use the largest size for the number_of_stack_items, but only get
+ // the right number of bytes.
+ u2 number_of_stack_items = Bytes::get_Java_u2(stackmap_p);
+ stackmap_p += 2;
+
+ for (u2 stack_i = 0; stack_i < number_of_stack_items; stack_i++) {
+ rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
+ calc_number_of_entries, frame_type, THREAD);
+ }
+ }
+ } // end while there is a stack_map_frame
+ assert(number_of_entries == calc_number_of_entries, "sanity check");
+} // end rewrite_cp_refs_in_stack_map_table()
+
+
+// Rewrite constant pool references in the verification type info
+// portion of the method's stackmap table. These "structures" are
+// adapted from the StackMapTable_attribute that is described in
+// section 4.8.4 of the 6.0 version of the VM spec (dated 2005.10.26):
+// file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf
+//
+// The verification_type_info structure is a u1 tag followed by 0 or
+// more bytes of data:
+//
+// union verification_type_info {
+// Top_variable_info;
+// Integer_variable_info;
+// Float_variable_info;
+// Long_variable_info;
+// Double_variable_info;
+// Null_variable_info;
+// UninitializedThis_variable_info;
+// Object_variable_info;
+// Uninitialized_variable_info;
+// }
+//
+void VM_RedefineClasses::rewrite_cp_refs_in_verification_type_info(
+ address& stackmap_p_ref, address stackmap_end, u2 frame_i,
+ u1 frame_type, TRAPS) {
+
+ assert(stackmap_p_ref + 1 <= stackmap_end, "no room for tag");
+ u1 tag = *stackmap_p_ref;
+ stackmap_p_ref++;
+
+ switch (tag) {
+ // Top_variable_info {
+ // u1 tag = ITEM_Top; /* 0 */
+ // }
+ // verificationType.hpp has zero as ITEM_Bogus instead of ITEM_Top
+ case 0: // fall through
+
+ // Integer_variable_info {
+ // u1 tag = ITEM_Integer; /* 1 */
+ // }
+ case ITEM_Integer: // fall through
+
+ // Float_variable_info {
+ // u1 tag = ITEM_Float; /* 2 */
+ // }
+ case ITEM_Float: // fall through
+
+ // Double_variable_info {
+ // u1 tag = ITEM_Double; /* 3 */
+ // }
+ case ITEM_Double: // fall through
+
+ // Long_variable_info {
+ // u1 tag = ITEM_Long; /* 4 */
+ // }
+ case ITEM_Long: // fall through
+
+ // Null_variable_info {
+ // u1 tag = ITEM_Null; /* 5 */
+ // }
+ case ITEM_Null: // fall through
+
+ // UninitializedThis_variable_info {
+ // u1 tag = ITEM_UninitializedThis; /* 6 */
+ // }
+ case ITEM_UninitializedThis:
+ // nothing more to do for the above tag types
+ break;
+
+ // Object_variable_info {
+ // u1 tag = ITEM_Object; /* 7 */
+ // u2 cpool_index;
+ // }
+ case ITEM_Object:
+ {
+ assert(stackmap_p_ref + 2 <= stackmap_end, "no room for cpool_index");
+ u2 cpool_index = Bytes::get_Java_u2(stackmap_p_ref);
+ u2 new_cp_index = find_new_index(cpool_index);
+ if (new_cp_index != 0) {
+ RC_TRACE_WITH_THREAD(0x04000000, THREAD,
+ ("mapped old cpool_index=%d", cpool_index));
+ Bytes::put_Java_u2(stackmap_p_ref, new_cp_index);
+ cpool_index = new_cp_index;
+ }
+ stackmap_p_ref += 2;
+
+ RC_TRACE_WITH_THREAD(0x04000000, THREAD,
+ ("frame_i=%u, frame_type=%u, cpool_index=%d", frame_i,
+ frame_type, cpool_index));
+ } break;
+
+ // Uninitialized_variable_info {
+ // u1 tag = ITEM_Uninitialized; /* 8 */
+ // u2 offset;
+ // }
+ case ITEM_Uninitialized:
+ assert(stackmap_p_ref + 2 <= stackmap_end, "no room for offset");
+ stackmap_p_ref += 2;
+ break;
+
+ default:
+ RC_TRACE_WITH_THREAD(0x04000000, THREAD,
+ ("frame_i=%u, frame_type=%u, bad tag=0x%x", frame_i, frame_type, tag));
+ ShouldNotReachHere();
+ break;
+ } // end switch (tag)
+} // end rewrite_cp_refs_in_verification_type_info()
+
+
+// Change the constant pool associated with klass scratch_class to
+// scratch_cp. If shrink is true, then scratch_cp_length elements
+// are copied from scratch_cp to a smaller constant pool and the
+// smaller constant pool is associated with scratch_class.
+void VM_RedefineClasses::set_new_constant_pool(
+ instanceKlassHandle scratch_class, constantPoolHandle scratch_cp,
+ int scratch_cp_length, bool shrink, TRAPS) {
+ assert(!shrink || scratch_cp->length() >= scratch_cp_length, "sanity check");
+
+ if (shrink) {
+ // scratch_cp is a merged constant pool and has enough space for a
+ // worst case merge situation. We want to associate the minimum
+ // sized constant pool with the klass to save space.
+ constantPoolHandle smaller_cp(THREAD,
+ oopFactory::new_constantPool(scratch_cp_length, THREAD));
+ // preserve orig_length() value in the smaller copy
+ int orig_length = scratch_cp->orig_length();
+ assert(orig_length != 0, "sanity check");
+ smaller_cp->set_orig_length(orig_length);
+ scratch_cp->copy_cp_to(1, scratch_cp_length - 1, smaller_cp, 1, THREAD);
+ scratch_cp = smaller_cp;
+ }
+
+ // attach new constant pool to klass
+ scratch_cp->set_pool_holder(scratch_class());
+
+ // attach klass to new constant pool
+ scratch_class->set_constants(scratch_cp());
+
+ int i; // for portability
+
+ // update each field in klass to use new constant pool indices as needed
+ typeArrayHandle fields(THREAD, scratch_class->fields());
+ int n_fields = fields->length();
+ for (i = 0; i < n_fields; i += instanceKlass::next_offset) {
+ jshort cur_index = fields->short_at(i + instanceKlass::name_index_offset);
+ jshort new_index = find_new_index(cur_index);
+ if (new_index != 0) {
+ RC_TRACE_WITH_THREAD(0x00080000, THREAD,
+ ("field-name_index change: %d to %d", cur_index, new_index));
+ fields->short_at_put(i + instanceKlass::name_index_offset, new_index);
+ }
+ cur_index = fields->short_at(i + instanceKlass::signature_index_offset);
+ new_index = find_new_index(cur_index);
+ if (new_index != 0) {
+ RC_TRACE_WITH_THREAD(0x00080000, THREAD,
+ ("field-signature_index change: %d to %d", cur_index, new_index));
+ fields->short_at_put(i + instanceKlass::signature_index_offset,
+ new_index);
+ }
+ cur_index = fields->short_at(i + instanceKlass::initval_index_offset);
+ new_index = find_new_index(cur_index);
+ if (new_index != 0) {
+ RC_TRACE_WITH_THREAD(0x00080000, THREAD,
+ ("field-initval_index change: %d to %d", cur_index, new_index));
+ fields->short_at_put(i + instanceKlass::initval_index_offset, new_index);
+ }
+ cur_index = fields->short_at(i + instanceKlass::generic_signature_offset);
+ new_index = find_new_index(cur_index);
+ if (new_index != 0) {
+ RC_TRACE_WITH_THREAD(0x00080000, THREAD,
+ ("field-generic_signature change: %d to %d", cur_index, new_index));
+ fields->short_at_put(i + instanceKlass::generic_signature_offset,
+ new_index);
+ }
+ } // end for each field
+
+ // Update constant pool indices in the inner classes info to use
+ // new constant indices as needed. The inner classes info is a
+ // quadruple:
+ // (inner_class_info, outer_class_info, inner_name, inner_access_flags)
+ typeArrayOop inner_class_list = scratch_class->inner_classes();
+ int icl_length = (inner_class_list == NULL) ? 0 : inner_class_list->length();
+ if (icl_length > 0) {
+ typeArrayHandle inner_class_list_h(THREAD, inner_class_list);
+ for (int i = 0; i < icl_length;
+ i += instanceKlass::inner_class_next_offset) {
+ int cur_index = inner_class_list_h->ushort_at(i
+ + instanceKlass::inner_class_inner_class_info_offset);
+ if (cur_index == 0) {
+ continue; // JVM spec. allows null inner class refs so skip it
+ }
+ int new_index = find_new_index(cur_index);
+ if (new_index != 0) {
+ RC_TRACE_WITH_THREAD(0x00080000, THREAD,
+ ("inner_class_info change: %d to %d", cur_index, new_index));
+ inner_class_list_h->ushort_at_put(i
+ + instanceKlass::inner_class_inner_class_info_offset, new_index);
+ }
+ cur_index = inner_class_list_h->ushort_at(i
+ + instanceKlass::inner_class_outer_class_info_offset);
+ new_index = find_new_index(cur_index);
+ if (new_index != 0) {
+ RC_TRACE_WITH_THREAD(0x00080000, THREAD,
+ ("outer_class_info change: %d to %d", cur_index, new_index));
+ inner_class_list_h->ushort_at_put(i
+ + instanceKlass::inner_class_outer_class_info_offset, new_index);
+ }
+ cur_index = inner_class_list_h->ushort_at(i
+ + instanceKlass::inner_class_inner_name_offset);
+ new_index = find_new_index(cur_index);
+ if (new_index != 0) {
+ RC_TRACE_WITH_THREAD(0x00080000, THREAD,
+ ("inner_name change: %d to %d", cur_index, new_index));
+ inner_class_list_h->ushort_at_put(i
+ + instanceKlass::inner_class_inner_name_offset, new_index);
+ }
+ } // end for each inner class
+ } // end if we have inner classes
+
+ // Attach each method in klass to the new constant pool and update
+ // to use new constant pool indices as needed:
+ objArrayHandle methods(THREAD, scratch_class->methods());
+ for (i = methods->length() - 1; i >= 0; i--) {
+ methodHandle method(THREAD, (methodOop)methods->obj_at(i));
+ method->set_constants(scratch_cp());
+
+ int new_index = find_new_index(method->name_index());
+ if (new_index != 0) {
+ RC_TRACE_WITH_THREAD(0x00080000, THREAD,
+ ("method-name_index change: %d to %d", method->name_index(),
+ new_index));
+ method->set_name_index(new_index);
+ }
+ new_index = find_new_index(method->signature_index());
+ if (new_index != 0) {
+ RC_TRACE_WITH_THREAD(0x00080000, THREAD,
+ ("method-signature_index change: %d to %d",
+ method->signature_index(), new_index));
+ method->set_signature_index(new_index);
+ }
+ new_index = find_new_index(method->generic_signature_index());
+ if (new_index != 0) {
+ RC_TRACE_WITH_THREAD(0x00080000, THREAD,
+ ("method-generic_signature_index change: %d to %d",
+ method->generic_signature_index(), new_index));
+ method->set_generic_signature_index(new_index);
+ }
+
+ // Update constant pool indices in the method's checked exception
+ // table to use new constant indices as needed.
+ int cext_length = method->checked_exceptions_length();
+ if (cext_length > 0) {
+ CheckedExceptionElement * cext_table =
+ method->checked_exceptions_start();
+ for (int j = 0; j < cext_length; j++) {
+ int cur_index = cext_table[j].class_cp_index;
+ int new_index = find_new_index(cur_index);
+ if (new_index != 0) {
+ RC_TRACE_WITH_THREAD(0x00080000, THREAD,
+ ("cext-class_cp_index change: %d to %d", cur_index, new_index));
+ cext_table[j].class_cp_index = (u2)new_index;
+ }
+ } // end for each checked exception table entry
+ } // end if there are checked exception table entries
+
+ // Update each catch type index in the method's exception table
+ // to use new constant pool indices as needed. The exception table
+ // holds quadruple entries of the form:
+ // (beg_bci, end_bci, handler_bci, klass_index)
+ const int beg_bci_offset = 0;
+ const int end_bci_offset = 1;
+ const int handler_bci_offset = 2;
+ const int klass_index_offset = 3;
+ const int entry_size = 4;
+
+ typeArrayHandle ex_table (THREAD, method->exception_table());
+ int ext_length = ex_table->length();
+ assert(ext_length % entry_size == 0, "exception table format has changed");
+
+ for (int j = 0; j < ext_length; j += entry_size) {
+ int cur_index = ex_table->int_at(j + klass_index_offset);
+ int new_index = find_new_index(cur_index);
+ if (new_index != 0) {
+ RC_TRACE_WITH_THREAD(0x00080000, THREAD,
+ ("ext-klass_index change: %d to %d", cur_index, new_index));
+ ex_table->int_at_put(j + klass_index_offset, new_index);
+ }
+ } // end for each exception table entry
+
+ // Update constant pool indices in the method's local variable
+ // table to use new constant indices as needed. The local variable
+ // table hold sextuple entries of the form:
+ // (start_pc, length, name_index, descriptor_index, signature_index, slot)
+ int lvt_length = method->localvariable_table_length();
+ if (lvt_length > 0) {
+ LocalVariableTableElement * lv_table =
+ method->localvariable_table_start();
+ for (int j = 0; j < lvt_length; j++) {
+ int cur_index = lv_table[j].name_cp_index;
+ int new_index = find_new_index(cur_index);
+ if (new_index != 0) {
+ RC_TRACE_WITH_THREAD(0x00080000, THREAD,
+ ("lvt-name_cp_index change: %d to %d", cur_index, new_index));
+ lv_table[j].name_cp_index = (u2)new_index;
+ }
+ cur_index = lv_table[j].descriptor_cp_index;
+ new_index = find_new_index(cur_index);
+ if (new_index != 0) {
+ RC_TRACE_WITH_THREAD(0x00080000, THREAD,
+ ("lvt-descriptor_cp_index change: %d to %d", cur_index,
+ new_index));
+ lv_table[j].descriptor_cp_index = (u2)new_index;
+ }
+ cur_index = lv_table[j].signature_cp_index;
+ new_index = find_new_index(cur_index);
+ if (new_index != 0) {
+ RC_TRACE_WITH_THREAD(0x00080000, THREAD,
+ ("lvt-signature_cp_index change: %d to %d", cur_index, new_index));
+ lv_table[j].signature_cp_index = (u2)new_index;
+ }
+ } // end for each local variable table entry
+ } // end if there are local variable table entries
+
+ rewrite_cp_refs_in_stack_map_table(method, THREAD);
+ } // end for each method
+} // end set_new_constant_pool()
+
+
+// Unevolving classes may point to methods of the_class directly
+// from their constant pool caches, itables, and/or vtables. We
+// use the SystemDictionary::classes_do() facility and this helper
+// to fix up these pointers.
+//
+// Note: We currently don't support updating the vtable in
+// arrayKlassOops. See Open Issues in jvmtiRedefineClasses.hpp.
+void VM_RedefineClasses::adjust_cpool_cache_and_vtable(klassOop k_oop,
+ oop initiating_loader, TRAPS) {
+ Klass *k = k_oop->klass_part();
+ if (k->oop_is_instance()) {
+ HandleMark hm(THREAD);
+ instanceKlass *ik = (instanceKlass *) k;
+
+ // HotSpot specific optimization! HotSpot does not currently
+ // support delegation from the bootstrap class loader to a
+ // user-defined class loader. This means that if the bootstrap
+ // class loader is the initiating class loader, then it will also
+ // be the defining class loader. This also means that classes
+ // loaded by the bootstrap class loader cannot refer to classes
+ // loaded by a user-defined class loader. Note: a user-defined
+ // class loader can delegate to the bootstrap class loader.
+ //
+ // If the current class being redefined has a user-defined class
+ // loader as its defining class loader, then we can skip all
+ // classes loaded by the bootstrap class loader.
+ bool is_user_defined =
+ instanceKlass::cast(_the_class_oop)->class_loader() != NULL;
+ if (is_user_defined && ik->class_loader() == NULL) {
+ return;
+ }
+
+ // This is a very busy routine. We don't want too much tracing
+ // printed out.
+ bool trace_name_printed = false;
+
+ // Very noisy: only enable this call if you are trying to determine
+ // that a specific class gets found by this routine.
+ // RC_TRACE macro has an embedded ResourceMark
+ // RC_TRACE_WITH_THREAD(0x00100000, THREAD,
+ // ("adjust check: name=%s", ik->external_name()));
+ // trace_name_printed = true;
+
+ // Fix the vtable embedded in the_class and subclasses of the_class,
+ // if one exists. We discard scratch_class and we don't keep an
+ // instanceKlass around to hold obsolete methods so we don't have
+ // any other instanceKlass embedded vtables to update. The vtable
+ // holds the methodOops for virtual (but not final) methods.
+ if (ik->vtable_length() > 0 && ik->is_subtype_of(_the_class_oop)) {
+ // ik->vtable() creates a wrapper object; rm cleans it up
+ ResourceMark rm(THREAD);
+ ik->vtable()->adjust_method_entries(_matching_old_methods,
+ _matching_new_methods,
+ _matching_methods_length,
+ &trace_name_printed);
+ }
+
+ // If the current class has an itable and we are either redefining an
+ // interface or if the current class is a subclass of the_class, then
+ // we potentially have to fix the itable. If we are redefining an
+ // interface, then we have to call adjust_method_entries() for
+ // every instanceKlass that has an itable since there isn't a
+ // subclass relationship between an interface and an instanceKlass.
+ if (ik->itable_length() > 0 && (Klass::cast(_the_class_oop)->is_interface()
+ || ik->is_subclass_of(_the_class_oop))) {
+ // ik->itable() creates a wrapper object; rm cleans it up
+ ResourceMark rm(THREAD);
+ ik->itable()->adjust_method_entries(_matching_old_methods,
+ _matching_new_methods,
+ _matching_methods_length,
+ &trace_name_printed);
+ }
+
+ // The constant pools in other classes (other_cp) can refer to
+ // methods in the_class. We have to update method information in
+ // other_cp's cache. If other_cp has a previous version, then we
+ // have to repeat the process for each previous version. The
+ // constant pool cache holds the methodOops for non-virtual
+ // methods and for virtual, final methods.
+ //
+ // Special case: if the current class is the_class, then new_cp
+ // has already been attached to the_class and old_cp has already
+ // been added as a previous version. The new_cp doesn't have any
+ // cached references to old methods so it doesn't need to be
+ // updated. We can simply start with the previous version(s) in
+ // that case.
+ constantPoolHandle other_cp;
+ constantPoolCacheOop cp_cache;
+
+ if (k_oop != _the_class_oop) {
+ // this klass' constant pool cache may need adjustment
+ other_cp = constantPoolHandle(ik->constants());
+ cp_cache = other_cp->cache();
+ if (cp_cache != NULL) {
+ cp_cache->adjust_method_entries(_matching_old_methods,
+ _matching_new_methods,
+ _matching_methods_length,
+ &trace_name_printed);
+ }
+ }
+ {
+ ResourceMark rm(THREAD);
+ // PreviousVersionInfo objects returned via PreviousVersionWalker
+ // contain a GrowableArray of handles. We have to clean up the
+ // GrowableArray _after_ the PreviousVersionWalker destructor
+ // has destroyed the handles.
+ {
+ // the previous versions' constant pool caches may need adjustment
+ PreviousVersionWalker pvw(ik);
+ for (PreviousVersionInfo * pv_info = pvw.next_previous_version();
+ pv_info != NULL; pv_info = pvw.next_previous_version()) {
+ other_cp = pv_info->prev_constant_pool_handle();
+ cp_cache = other_cp->cache();
+ if (cp_cache != NULL) {
+ cp_cache->adjust_method_entries(_matching_old_methods,
+ _matching_new_methods,
+ _matching_methods_length,
+ &trace_name_printed);
+ }
+ }
+ } // pvw is cleaned up
+ } // rm is cleaned up
+ }
+}
+
+void VM_RedefineClasses::update_jmethod_ids() {
+ for (int j = 0; j < _matching_methods_length; ++j) {
+ methodOop old_method = _matching_old_methods[j];
+ jmethodID jmid = old_method->find_jmethod_id_or_null();
+ if (jmid != NULL) {
+ // There is a jmethodID, change it to point to the new method
+ methodHandle new_method_h(_matching_new_methods[j]);
+ JNIHandles::change_method_associated_with_jmethod_id(jmid, new_method_h);
+ assert(JNIHandles::resolve_jmethod_id(jmid) == _matching_new_methods[j],
+ "should be replaced");
+ }
+ }
+}
+
+void VM_RedefineClasses::check_methods_and_mark_as_obsolete(
+ BitMap *emcp_methods, int * emcp_method_count_p) {
+ *emcp_method_count_p = 0;
+ int obsolete_count = 0;
+ int old_index = 0;
+ for (int j = 0; j < _matching_methods_length; ++j, ++old_index) {
+ methodOop old_method = _matching_old_methods[j];
+ methodOop new_method = _matching_new_methods[j];
+ methodOop old_array_method;
+
+ // Maintain an old_index into the _old_methods array by skipping
+ // deleted methods
+ while ((old_array_method = (methodOop) _old_methods->obj_at(old_index))
+ != old_method) {
+ ++old_index;
+ }
+
+ if (MethodComparator::methods_EMCP(old_method, new_method)) {
+ // The EMCP definition from JSR-163 requires the bytecodes to be
+ // the same with the exception of constant pool indices which may
+ // differ. However, the constants referred to by those indices
+ // must be the same.
+ //
+ // We use methods_EMCP() for comparison since constant pool
+ // merging can remove duplicate constant pool entries that were
+ // present in the old method and removed from the rewritten new
+ // method. A faster binary comparison function would consider the
+ // old and new methods to be different when they are actually
+ // EMCP.
+ //
+ // The old and new methods are EMCP and you would think that we
+ // could get rid of one of them here and now and save some space.
+ // However, the concept of EMCP only considers the bytecodes and
+ // the constant pool entries in the comparison. Other things,
+ // e.g., the line number table (LNT) or the local variable table
+ // (LVT) don't count in the comparison. So the new (and EMCP)
+ // method can have a new LNT that we need so we can't just
+ // overwrite the new method with the old method.
+ //
+ // When this routine is called, we have already attached the new
+ // methods to the_class so the old methods are effectively
+ // overwritten. However, if an old method is still executing,
+ // then the old method cannot be collected until sometime after
+ // the old method call has returned. So the overwriting of old
+ // methods by new methods will save us space except for those
+ // (hopefully few) old methods that are still executing.
+ //
+ // A method refers to a constMethodOop and this presents another
+ // possible avenue to space savings. The constMethodOop in the
+ // new method contains possibly new attributes (LNT, LVT, etc).
+ // At first glance, it seems possible to save space by replacing
+ // the constMethodOop in the old method with the constMethodOop
+ // from the new method. The old and new methods would share the
+ // same constMethodOop and we would save the space occupied by
+ // the old constMethodOop. However, the constMethodOop contains
+ // a back reference to the containing method. Sharing the
+ // constMethodOop between two methods could lead to confusion in
+ // the code that uses the back reference. This would lead to
+ // brittle code that could be broken in non-obvious ways now or
+ // in the future.
+ //
+ // Another possibility is to copy the constMethodOop from the new
+ // method to the old method and then overwrite the new method with
+ // the old method. Since the constMethodOop contains the bytecodes
+ // for the method embedded in the oop, this option would change
+ // the bytecodes out from under any threads executing the old
+ // method and make the thread's bcp invalid. Since EMCP requires
+ // that the bytecodes be the same modulo constant pool indices, it
+ // is straight forward to compute the correct new bcp in the new
+ // constMethodOop from the old bcp in the old constMethodOop. The
+ // time consuming part would be searching all the frames in all
+ // of the threads to find all of the calls to the old method.
+ //
+ // It looks like we will have to live with the limited savings
+ // that we get from effectively overwriting the old methods
+ // when the new methods are attached to the_class.
+
+ // track which methods are EMCP for add_previous_version() call
+ emcp_methods->set_bit(old_index);
+ (*emcp_method_count_p)++;
+
+ // An EMCP method is _not_ obsolete. An obsolete method has a
+ // different jmethodID than the current method. An EMCP method
+ // has the same jmethodID as the current method. Having the
+ // same jmethodID for all EMCP versions of a method allows for
+ // a consistent view of the EMCP methods regardless of which
+ // EMCP method you happen to have in hand. For example, a
+ // breakpoint set in one EMCP method will work for all EMCP
+ // versions of the method including the current one.
+ } else {
+ // mark obsolete methods as such
+ old_method->set_is_obsolete();
+ obsolete_count++;
+
+ // obsolete methods need a unique idnum
+ u2 num = instanceKlass::cast(_the_class_oop)->next_method_idnum();
+ if (num != constMethodOopDesc::UNSET_IDNUM) {
+// u2 old_num = old_method->method_idnum();
+ old_method->set_method_idnum(num);
+// TO DO: attach obsolete annotations to obsolete method's new idnum
+ }
+ // With tracing we try not to "yack" too much. The position of
+ // this trace assumes there are fewer obsolete methods than
+ // EMCP methods.
+ RC_TRACE(0x00000100, ("mark %s(%s) as obsolete",
+ old_method->name()->as_C_string(),
+ old_method->signature()->as_C_string()));
+ }
+ old_method->set_is_old();
+ }
+ for (int i = 0; i < _deleted_methods_length; ++i) {
+ methodOop old_method = _deleted_methods[i];
+
+ assert(old_method->vtable_index() < 0,
+ "cannot delete methods with vtable entries");;
+
+ // Mark all deleted methods as old and obsolete
+ old_method->set_is_old();
+ old_method->set_is_obsolete();
+ ++obsolete_count;
+ // With tracing we try not to "yack" too much. The position of
+ // this trace assumes there are fewer obsolete methods than
+ // EMCP methods.
+ RC_TRACE(0x00000100, ("mark deleted %s(%s) as obsolete",
+ old_method->name()->as_C_string(),
+ old_method->signature()->as_C_string()));
+ }
+ assert((*emcp_method_count_p + obsolete_count) == _old_methods->length(),
+ "sanity check");
+ RC_TRACE(0x00000100, ("EMCP_cnt=%d, obsolete_cnt=%d", *emcp_method_count_p,
+ obsolete_count));
+}
+
+// This internal class transfers the native function registration from old methods
+// to new methods. It is designed to handle both the simple case of unchanged
+// native methods and the complex cases of native method prefixes being added and/or
+// removed.
+// It expects only to be used during the VM_RedefineClasses op (a safepoint).
+//
+// This class is used after the new methods have been installed in "the_class".
+//
+// So, for example, the following must be handled. Where 'm' is a method and
+// a number followed by an underscore is a prefix.
+//
+// Old Name New Name
+// Simple transfer to new method m -> m
+// Add prefix m -> 1_m
+// Remove prefix 1_m -> m
+// Simultaneous add of prefixes m -> 3_2_1_m
+// Simultaneous removal of prefixes 3_2_1_m -> m
+// Simultaneous add and remove 1_m -> 2_m
+// Same, caused by prefix removal only 3_2_1_m -> 3_2_m
+//
+class TransferNativeFunctionRegistration {
+ private:
+ instanceKlassHandle the_class;
+ int prefix_count;
+ char** prefixes;
+
+ // Recursively search the binary tree of possibly prefixed method names.
+ // Iteration could be used if all agents were well behaved. Full tree walk is
+ // more resilent to agents not cleaning up intermediate methods.
+ // Branch at each depth in the binary tree is:
+ // (1) without the prefix.
+ // (2) with the prefix.
+ // where 'prefix' is the prefix at that 'depth' (first prefix, second prefix,...)
+ methodOop search_prefix_name_space(int depth, char* name_str, size_t name_len,
+ symbolOop signature) {
+ symbolOop name_symbol = SymbolTable::probe(name_str, (int)name_len);
+ if (name_symbol != NULL) {
+ methodOop method = Klass::cast(the_class())->lookup_method(name_symbol, signature);
+ if (method != NULL) {
+ // Even if prefixed, intermediate methods must exist.
+ if (method->is_native()) {
+ // Wahoo, we found a (possibly prefixed) version of the method, return it.
+ return method;
+ }
+ if (depth < prefix_count) {
+ // Try applying further prefixes (other than this one).
+ method = search_prefix_name_space(depth+1, name_str, name_len, signature);
+ if (method != NULL) {
+ return method; // found
+ }
+
+ // Try adding this prefix to the method name and see if it matches
+ // another method name.
+ char* prefix = prefixes[depth];
+ size_t prefix_len = strlen(prefix);
+ size_t trial_len = name_len + prefix_len;
+ char* trial_name_str = NEW_RESOURCE_ARRAY(char, trial_len + 1);
+ strcpy(trial_name_str, prefix);
+ strcat(trial_name_str, name_str);
+ method = search_prefix_name_space(depth+1, trial_name_str, trial_len,
+ signature);
+ if (method != NULL) {
+ // If found along this branch, it was prefixed, mark as such
+ method->set_is_prefixed_native();
+ return method; // found
+ }
+ }
+ }
+ }
+ return NULL; // This whole branch bore nothing
+ }
+
+ // Return the method name with old prefixes stripped away.
+ char* method_name_without_prefixes(methodOop method) {
+ symbolOop name = method->name();
+ char* name_str = name->as_utf8();
+
+ // Old prefixing may be defunct, strip prefixes, if any.
+ for (int i = prefix_count-1; i >= 0; i--) {
+ char* prefix = prefixes[i];
+ size_t prefix_len = strlen(prefix);
+ if (strncmp(prefix, name_str, prefix_len) == 0) {
+ name_str += prefix_len;
+ }
+ }
+ return name_str;
+ }
+
+ // Strip any prefixes off the old native method, then try to find a
+ // (possibly prefixed) new native that matches it.
+ methodOop strip_and_search_for_new_native(methodOop method) {
+ ResourceMark rm;
+ char* name_str = method_name_without_prefixes(method);
+ return search_prefix_name_space(0, name_str, strlen(name_str),
+ method->signature());
+ }
+
+ public:
+
+ // Construct a native method transfer processor for this class.
+ TransferNativeFunctionRegistration(instanceKlassHandle _the_class) {
+ assert(SafepointSynchronize::is_at_safepoint(), "sanity check");
+
+ the_class = _the_class;
+ prefixes = JvmtiExport::get_all_native_method_prefixes(&prefix_count);
+ }
+
+ // Attempt to transfer any of the old or deleted methods that are native
+ void transfer_registrations(methodOop* old_methods, int methods_length) {
+ for (int j = 0; j < methods_length; j++) {
+ methodOop old_method = old_methods[j];
+
+ if (old_method->is_native() && old_method->has_native_function()) {
+ methodOop new_method = strip_and_search_for_new_native(old_method);
+ if (new_method != NULL) {
+ // Actually set the native function in the new method.
+ // Redefine does not send events (except CFLH), certainly not this
+ // behind the scenes re-registration.
+ new_method->set_native_function(old_method->native_function(),
+ !methodOopDesc::native_bind_event_is_interesting);
+ }
+ }
+ }
+ }
+};
+
+// Don't lose the association between a native method and its JNI function.
+void VM_RedefineClasses::transfer_old_native_function_registrations(instanceKlassHandle the_class) {
+ TransferNativeFunctionRegistration transfer(the_class);
+ transfer.transfer_registrations(_deleted_methods, _deleted_methods_length);
+ transfer.transfer_registrations(_matching_old_methods, _matching_methods_length);
+}
+
+// Deoptimize all compiled code that depends on this class.
+//
+// If the can_redefine_classes capability is obtained in the onload
+// phase then the compiler has recorded all dependencies from startup.
+// In that case we need only deoptimize and throw away all compiled code
+// that depends on the class.
+//
+// If can_redefine_classes is obtained sometime after the onload
+// phase then the dependency information may be incomplete. In that case
+// the first call to RedefineClasses causes all compiled code to be
+// thrown away. As can_redefine_classes has been obtained then
+// all future compilations will record dependencies so second and
+// subsequent calls to RedefineClasses need only throw away code
+// that depends on the class.
+//
+void VM_RedefineClasses::flush_dependent_code(instanceKlassHandle k_h, TRAPS) {
+ assert_locked_or_safepoint(Compile_lock);
+
+ // All dependencies have been recorded from startup or this is a second or
+ // subsequent use of RedefineClasses
+ if (JvmtiExport::all_dependencies_are_recorded()) {
+ Universe::flush_evol_dependents_on(k_h);
+ } else {
+ CodeCache::mark_all_nmethods_for_deoptimization();
+
+ ResourceMark rm(THREAD);
+ DeoptimizationMarker dm;
+
+ // Deoptimize all activations depending on marked nmethods
+ Deoptimization::deoptimize_dependents();
+
+ // Make the dependent methods not entrant (in VM_Deoptimize they are made zombies)
+ CodeCache::make_marked_nmethods_not_entrant();
+
+ // From now on we know that the dependency information is complete
+ JvmtiExport::set_all_dependencies_are_recorded(true);
+ }
+}
+
+void VM_RedefineClasses::compute_added_deleted_matching_methods() {
+ methodOop old_method;
+ methodOop new_method;
+
+ _matching_old_methods = NEW_RESOURCE_ARRAY(methodOop, _old_methods->length());
+ _matching_new_methods = NEW_RESOURCE_ARRAY(methodOop, _old_methods->length());
+ _added_methods = NEW_RESOURCE_ARRAY(methodOop, _new_methods->length());
+ _deleted_methods = NEW_RESOURCE_ARRAY(methodOop, _old_methods->length());
+
+ _matching_methods_length = 0;
+ _deleted_methods_length = 0;
+ _added_methods_length = 0;
+
+ int nj = 0;
+ int oj = 0;
+ while (true) {
+ if (oj >= _old_methods->length()) {
+ if (nj >= _new_methods->length()) {
+ break; // we've looked at everything, done
+ }
+ // New method at the end
+ new_method = (methodOop) _new_methods->obj_at(nj);
+ _added_methods[_added_methods_length++] = new_method;
+ ++nj;
+ } else if (nj >= _new_methods->length()) {
+ // Old method, at the end, is deleted
+ old_method = (methodOop) _old_methods->obj_at(oj);
+ _deleted_methods[_deleted_methods_length++] = old_method;
+ ++oj;
+ } else {
+ old_method = (methodOop) _old_methods->obj_at(oj);
+ new_method = (methodOop) _new_methods->obj_at(nj);
+ if (old_method->name() == new_method->name()) {
+ if (old_method->signature() == new_method->signature()) {
+ _matching_old_methods[_matching_methods_length ] = old_method;
+ _matching_new_methods[_matching_methods_length++] = new_method;
+ ++nj;
+ ++oj;
+ } else {
+ // added overloaded have already been moved to the end,
+ // so this is a deleted overloaded method
+ _deleted_methods[_deleted_methods_length++] = old_method;
+ ++oj;
+ }
+ } else { // names don't match
+ if (old_method->name()->fast_compare(new_method->name()) > 0) {
+ // new method
+ _added_methods[_added_methods_length++] = new_method;
+ ++nj;
+ } else {
+ // deleted method
+ _deleted_methods[_deleted_methods_length++] = old_method;
+ ++oj;
+ }
+ }
+ }
+ }
+ assert(_matching_methods_length + _deleted_methods_length == _old_methods->length(), "sanity");
+ assert(_matching_methods_length + _added_methods_length == _new_methods->length(), "sanity");
+}
+
+
+
+// Install the redefinition of a class:
+// - house keeping (flushing breakpoints and caches, deoptimizing
+// dependent compiled code)
+// - replacing parts in the_class with parts from scratch_class
+// - adding a weak reference to track the obsolete but interesting
+// parts of the_class
+// - adjusting constant pool caches and vtables in other classes
+// that refer to methods in the_class. These adjustments use the
+// SystemDictionary::classes_do() facility which only allows
+// a helper method to be specified. The interesting parameters
+// that we would like to pass to the helper method are saved in
+// static global fields in the VM operation.
+void VM_RedefineClasses::redefine_single_class(jclass the_jclass,
+ instanceKlassHandle scratch_class, TRAPS) {
+
+ RC_TIMER_START(_timer_rsc_phase1);
+
+ oop the_class_mirror = JNIHandles::resolve_non_null(the_jclass);
+ klassOop the_class_oop = java_lang_Class::as_klassOop(the_class_mirror);
+ instanceKlassHandle the_class = instanceKlassHandle(THREAD, the_class_oop);
+
+#ifndef JVMTI_KERNEL
+ // Remove all breakpoints in methods of this class
+ JvmtiBreakpoints& jvmti_breakpoints = JvmtiCurrentBreakpoints::get_jvmti_breakpoints();
+ jvmti_breakpoints.clearall_in_class_at_safepoint(the_class_oop);
+#endif // !JVMTI_KERNEL
+
+ if (the_class_oop == Universe::reflect_invoke_cache()->klass()) {
+ // We are redefining java.lang.reflect.Method. Method.invoke() is
+ // cached and users of the cache care about each active version of
+ // the method so we have to track this previous version.
+ // Do this before methods get switched
+ Universe::reflect_invoke_cache()->add_previous_version(
+ the_class->method_with_idnum(Universe::reflect_invoke_cache()->method_idnum()));
+ }
+
+ // Deoptimize all compiled code that depends on this class
+ flush_dependent_code(the_class, THREAD);
+
+ _old_methods = the_class->methods();
+ _new_methods = scratch_class->methods();
+ _the_class_oop = the_class_oop;
+ compute_added_deleted_matching_methods();
+ update_jmethod_ids();
+
+ // Attach new constant pool to the original klass. The original
+ // klass still refers to the old constant pool (for now).
+ scratch_class->constants()->set_pool_holder(the_class());
+
+#if 0
+ // In theory, with constant pool merging in place we should be able
+ // to save space by using the new, merged constant pool in place of
+ // the old constant pool(s). By "pool(s)" I mean the constant pool in
+ // the klass version we are replacing now and any constant pool(s) in
+ // previous versions of klass. Nice theory, doesn't work in practice.
+ // When this code is enabled, even simple programs throw NullPointer
+ // exceptions. I'm guessing that this is caused by some constant pool
+ // cache difference between the new, merged constant pool and the
+ // constant pool that was just being used by the klass. I'm keeping
+ // this code around to archive the idea, but the code has to remain
+ // disabled for now.
+
+ // Attach each old method to the new constant pool. This can be
+ // done here since we are past the bytecode verification and
+ // constant pool optimization phases.
+ for (int i = _old_methods->length() - 1; i >= 0; i--) {
+ methodOop method = (methodOop)_old_methods->obj_at(i);
+ method->set_constants(scratch_class->constants());
+ }
+
+ {
+ // walk all previous versions of the klass
+ instanceKlass *ik = (instanceKlass *)the_class()->klass_part();
+ PreviousVersionWalker pvw(ik);
+ instanceKlassHandle ikh;
+ do {
+ ikh = pvw.next_previous_version();
+ if (!ikh.is_null()) {
+ ik = ikh();
+
+ // attach previous version of klass to the new constant pool
+ ik->set_constants(scratch_class->constants());
+
+ // Attach each method in the previous version of klass to the
+ // new constant pool
+ objArrayOop prev_methods = ik->methods();
+ for (int i = prev_methods->length() - 1; i >= 0; i--) {
+ methodOop method = (methodOop)prev_methods->obj_at(i);
+ method->set_constants(scratch_class->constants());
+ }
+ }
+ } while (!ikh.is_null());
+ }
+#endif
+
+ // Replace methods and constantpool
+ the_class->set_methods(_new_methods);
+ scratch_class->set_methods(_old_methods); // To prevent potential GCing of the old methods,
+ // and to be able to undo operation easily.
+
+ constantPoolOop old_constants = the_class->constants();
+ the_class->set_constants(scratch_class->constants());
+ scratch_class->set_constants(old_constants); // See the previous comment.
+#if 0
+ // We are swapping the guts of "the new class" with the guts of "the
+ // class". Since the old constant pool has just been attached to "the
+ // new class", it seems logical to set the pool holder in the old
+ // constant pool also. However, doing this will change the observable
+ // class hierarchy for any old methods that are still executing. A
+ // method can query the identity of its "holder" and this query uses
+ // the method's constant pool link to find the holder. The change in
+ // holding class from "the class" to "the new class" can confuse
+ // things.
+ //
+ // Setting the old constant pool's holder will also cause
+ // verification done during vtable initialization below to fail.
+ // During vtable initialization, the vtable's class is verified to be
+ // a subtype of the method's holder. The vtable's class is "the
+ // class" and the method's holder is gotten from the constant pool
+ // link in the method itself. For "the class"'s directly implemented
+ // methods, the method holder is "the class" itself (as gotten from
+ // the new constant pool). The check works fine in this case. The
+ // check also works fine for methods inherited from super classes.
+ //
+ // Miranda methods are a little more complicated. A miranda method is
+ // provided by an interface when the class implementing the interface
+ // does not provide its own method. These interfaces are implemented
+ // internally as an instanceKlass. These special instanceKlasses
+ // share the constant pool of the class that "implements" the
+ // interface. By sharing the constant pool, the method holder of a
+ // miranda method is the class that "implements" the interface. In a
+ // non-redefine situation, the subtype check works fine. However, if
+ // the old constant pool's pool holder is modified, then the check
+ // fails because there is no class hierarchy relationship between the
+ // vtable's class and "the new class".
+
+ old_constants->set_pool_holder(scratch_class());
+#endif
+
+ // track which methods are EMCP for add_previous_version() call below
+ BitMap emcp_methods(_old_methods->length());
+ int emcp_method_count = 0;
+ emcp_methods.clear(); // clears 0..(length() - 1)
+ check_methods_and_mark_as_obsolete(&emcp_methods, &emcp_method_count);
+ transfer_old_native_function_registrations(the_class);
+
+ // The class file bytes from before any retransformable agents mucked
+ // with them was cached on the scratch class, move to the_class.
+ // Note: we still want to do this if nothing needed caching since it
+ // should get cleared in the_class too.
+ the_class->set_cached_class_file(scratch_class->get_cached_class_file_bytes(),
+ scratch_class->get_cached_class_file_len());
+
+ // Replace inner_classes
+ typeArrayOop old_inner_classes = the_class->inner_classes();
+ the_class->set_inner_classes(scratch_class->inner_classes());
+ scratch_class->set_inner_classes(old_inner_classes);
+
+ // Initialize the vtable and interface table after
+ // methods have been rewritten
+ {
+ ResourceMark rm(THREAD);
+ // no exception should happen here since we explicitly
+ // do not check loader constraints.
+ // compare_and_normalize_class_versions has already checked:
+ // - classloaders unchanged, signatures unchanged
+ // - all instanceKlasses for redefined classes reused & contents updated
+ the_class->vtable()->initialize_vtable(false, THREAD);
+ the_class->itable()->initialize_itable(false, THREAD);
+ assert(!HAS_PENDING_EXCEPTION || (THREAD->pending_exception()->is_a(SystemDictionary::threaddeath_klass())), "redefine exception");
+ }
+
+ // Leave arrays of jmethodIDs and itable index cache unchanged
+
+ // Copy the "source file name" attribute from new class version
+ the_class->set_source_file_name(scratch_class->source_file_name());
+
+ // Copy the "source debug extension" attribute from new class version
+ the_class->set_source_debug_extension(
+ scratch_class->source_debug_extension());
+
+ // Use of javac -g could be different in the old and the new
+ if (scratch_class->access_flags().has_localvariable_table() !=
+ the_class->access_flags().has_localvariable_table()) {
+
+ AccessFlags flags = the_class->access_flags();
+ if (scratch_class->access_flags().has_localvariable_table()) {
+ flags.set_has_localvariable_table();
+ } else {
+ flags.clear_has_localvariable_table();
+ }
+ the_class->set_access_flags(flags);
+ }
+
+ // Replace class annotation fields values
+ typeArrayOop old_class_annotations = the_class->class_annotations();
+ the_class->set_class_annotations(scratch_class->class_annotations());
+ scratch_class->set_class_annotations(old_class_annotations);
+
+ // Replace fields annotation fields values
+ objArrayOop old_fields_annotations = the_class->fields_annotations();
+ the_class->set_fields_annotations(scratch_class->fields_annotations());
+ scratch_class->set_fields_annotations(old_fields_annotations);
+
+ // Replace methods annotation fields values
+ objArrayOop old_methods_annotations = the_class->methods_annotations();
+ the_class->set_methods_annotations(scratch_class->methods_annotations());
+ scratch_class->set_methods_annotations(old_methods_annotations);
+
+ // Replace methods parameter annotation fields values
+ objArrayOop old_methods_parameter_annotations =
+ the_class->methods_parameter_annotations();
+ the_class->set_methods_parameter_annotations(
+ scratch_class->methods_parameter_annotations());
+ scratch_class->set_methods_parameter_annotations(old_methods_parameter_annotations);
+
+ // Replace methods default annotation fields values
+ objArrayOop old_methods_default_annotations =
+ the_class->methods_default_annotations();
+ the_class->set_methods_default_annotations(
+ scratch_class->methods_default_annotations());
+ scratch_class->set_methods_default_annotations(old_methods_default_annotations);
+
+ // Replace minor version number of class file
+ u2 old_minor_version = the_class->minor_version();
+ the_class->set_minor_version(scratch_class->minor_version());
+ scratch_class->set_minor_version(old_minor_version);
+
+ // Replace major version number of class file
+ u2 old_major_version = the_class->major_version();
+ the_class->set_major_version(scratch_class->major_version());
+ scratch_class->set_major_version(old_major_version);
+
+ // Replace CP indexes for class and name+type of enclosing method
+ u2 old_class_idx = the_class->enclosing_method_class_index();
+ u2 old_method_idx = the_class->enclosing_method_method_index();
+ the_class->set_enclosing_method_indices(
+ scratch_class->enclosing_method_class_index(),
+ scratch_class->enclosing_method_method_index());
+ scratch_class->set_enclosing_method_indices(old_class_idx, old_method_idx);
+
+ // keep track of previous versions of this class
+ the_class->add_previous_version(scratch_class, &emcp_methods,
+ emcp_method_count);
+
+ RC_TIMER_STOP(_timer_rsc_phase1);
+ RC_TIMER_START(_timer_rsc_phase2);
+
+ // Adjust constantpool caches and vtables for all classes
+ // that reference methods of the evolved class.
+ SystemDictionary::classes_do(adjust_cpool_cache_and_vtable, THREAD);
+
+ if (the_class->oop_map_cache() != NULL) {
+ // Flush references to any obsolete methods from the oop map cache
+ // so that obsolete methods are not pinned.
+ the_class->oop_map_cache()->flush_obsolete_entries();
+ }
+
+ // increment the classRedefinedCount field in the_class and in any
+ // direct and indirect subclasses of the_class
+ increment_class_counter((instanceKlass *)the_class()->klass_part(), THREAD);
+
+ // RC_TRACE macro has an embedded ResourceMark
+ RC_TRACE_WITH_THREAD(0x00000001, THREAD,
+ ("redefined name=%s, count=%d (avail_mem=" UINT64_FORMAT "K)",
+ the_class->external_name(),
+ java_lang_Class::classRedefinedCount(the_class_mirror),
+ os::available_memory() >> 10));
+
+ RC_TIMER_STOP(_timer_rsc_phase2);
+} // end redefine_single_class()
+
+
+// Increment the classRedefinedCount field in the specific instanceKlass
+// and in all direct and indirect subclasses.
+void VM_RedefineClasses::increment_class_counter(instanceKlass *ik, TRAPS) {
+ oop class_mirror = ik->java_mirror();
+ klassOop class_oop = java_lang_Class::as_klassOop(class_mirror);
+ int new_count = java_lang_Class::classRedefinedCount(class_mirror) + 1;
+ java_lang_Class::set_classRedefinedCount(class_mirror, new_count);
+
+ if (class_oop != _the_class_oop) {
+ // _the_class_oop count is printed at end of redefine_single_class()
+ RC_TRACE_WITH_THREAD(0x00000008, THREAD,
+ ("updated count in subclass=%s to %d", ik->external_name(), new_count));
+ }
+
+ for (Klass *subk = ik->subklass(); subk != NULL;
+ subk = subk->next_sibling()) {
+ klassOop sub = subk->as_klassOop();
+ instanceKlass *subik = (instanceKlass *)sub->klass_part();
+
+ // recursively do subclasses of the current subclass
+ increment_class_counter(subik, THREAD);
+ }
+}
+
+#ifndef PRODUCT
+void VM_RedefineClasses::check_class(klassOop k_oop,
+ oop initiating_loader, TRAPS) {
+ Klass *k = k_oop->klass_part();
+ if (k->oop_is_instance()) {
+ HandleMark hm(THREAD);
+ instanceKlass *ik = (instanceKlass *) k;
+
+ if (ik->vtable_length() > 0) {
+ ResourceMark rm(THREAD);
+ if (!ik->vtable()->check_no_old_entries()) {
+ tty->print_cr("klassVtable::check_no_old_entries failure -- OLD method found -- class: %s", ik->signature_name());
+ ik->vtable()->dump_vtable();
+ dump_methods();
+ assert(false, "OLD method found");
+ }
+ }
+ }
+}
+
+void VM_RedefineClasses::dump_methods() {
+ int j;
+ tty->print_cr("_old_methods --");
+ for (j = 0; j < _old_methods->length(); ++j) {
+ methodOop m = (methodOop) _old_methods->obj_at(j);
+ tty->print("%4d (%5d) ", j, m->vtable_index());
+ m->access_flags().print_on(tty);
+ tty->print(" -- ");
+ m->print_name(tty);
+ tty->cr();
+ }
+ tty->print_cr("_new_methods --");
+ for (j = 0; j < _new_methods->length(); ++j) {
+ methodOop m = (methodOop) _new_methods->obj_at(j);
+ tty->print("%4d (%5d) ", j, m->vtable_index());
+ m->access_flags().print_on(tty);
+ tty->print(" -- ");
+ m->print_name(tty);
+ tty->cr();
+ }
+ tty->print_cr("_matching_(old/new)_methods --");
+ for (j = 0; j < _matching_methods_length; ++j) {
+ methodOop m = _matching_old_methods[j];
+ tty->print("%4d (%5d) ", j, m->vtable_index());
+ m->access_flags().print_on(tty);
+ tty->print(" -- ");
+ m->print_name(tty);
+ tty->cr();
+ m = _matching_new_methods[j];
+ tty->print(" (%5d) ", m->vtable_index());
+ m->access_flags().print_on(tty);
+ tty->cr();
+ }
+ tty->print_cr("_deleted_methods --");
+ for (j = 0; j < _deleted_methods_length; ++j) {
+ methodOop m = _deleted_methods[j];
+ tty->print("%4d (%5d) ", j, m->vtable_index());
+ m->access_flags().print_on(tty);
+ tty->print(" -- ");
+ m->print_name(tty);
+ tty->cr();
+ }
+ tty->print_cr("_added_methods --");
+ for (j = 0; j < _added_methods_length; ++j) {
+ methodOop m = _added_methods[j];
+ tty->print("%4d (%5d) ", j, m->vtable_index());
+ m->access_flags().print_on(tty);
+ tty->print(" -- ");
+ m->print_name(tty);
+ tty->cr();
+ }
+}
+#endif