1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/src/share/vm/prims/jvmtiRedefineClasses.cpp Wed Apr 27 01:25:04 2016 +0800
1.3 @@ -0,0 +1,3658 @@
1.4 +/*
1.5 + * Copyright (c) 2003, 2014, Oracle and/or its affiliates. All rights reserved.
1.6 + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
1.7 + *
1.8 + * This code is free software; you can redistribute it and/or modify it
1.9 + * under the terms of the GNU General Public License version 2 only, as
1.10 + * published by the Free Software Foundation.
1.11 + *
1.12 + * This code is distributed in the hope that it will be useful, but WITHOUT
1.13 + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
1.14 + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
1.15 + * version 2 for more details (a copy is included in the LICENSE file that
1.16 + * accompanied this code).
1.17 + *
1.18 + * You should have received a copy of the GNU General Public License version
1.19 + * 2 along with this work; if not, write to the Free Software Foundation,
1.20 + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
1.21 + *
1.22 + * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
1.23 + * or visit www.oracle.com if you need additional information or have any
1.24 + * questions.
1.25 + *
1.26 + */
1.27 +
1.28 +#include "precompiled.hpp"
1.29 +#include "classfile/metadataOnStackMark.hpp"
1.30 +#include "classfile/systemDictionary.hpp"
1.31 +#include "classfile/verifier.hpp"
1.32 +#include "code/codeCache.hpp"
1.33 +#include "compiler/compileBroker.hpp"
1.34 +#include "interpreter/oopMapCache.hpp"
1.35 +#include "interpreter/rewriter.hpp"
1.36 +#include "memory/gcLocker.hpp"
1.37 +#include "memory/metadataFactory.hpp"
1.38 +#include "memory/metaspaceShared.hpp"
1.39 +#include "memory/universe.inline.hpp"
1.40 +#include "oops/fieldStreams.hpp"
1.41 +#include "oops/klassVtable.hpp"
1.42 +#include "prims/jvmtiImpl.hpp"
1.43 +#include "prims/jvmtiRedefineClasses.hpp"
1.44 +#include "prims/methodComparator.hpp"
1.45 +#include "runtime/deoptimization.hpp"
1.46 +#include "runtime/relocator.hpp"
1.47 +#include "utilities/bitMap.inline.hpp"
1.48 +
1.49 +PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
1.50 +
1.51 +Array<Method*>* VM_RedefineClasses::_old_methods = NULL;
1.52 +Array<Method*>* VM_RedefineClasses::_new_methods = NULL;
1.53 +Method** VM_RedefineClasses::_matching_old_methods = NULL;
1.54 +Method** VM_RedefineClasses::_matching_new_methods = NULL;
1.55 +Method** VM_RedefineClasses::_deleted_methods = NULL;
1.56 +Method** VM_RedefineClasses::_added_methods = NULL;
1.57 +int VM_RedefineClasses::_matching_methods_length = 0;
1.58 +int VM_RedefineClasses::_deleted_methods_length = 0;
1.59 +int VM_RedefineClasses::_added_methods_length = 0;
1.60 +Klass* VM_RedefineClasses::_the_class_oop = NULL;
1.61 +
1.62 +
1.63 +VM_RedefineClasses::VM_RedefineClasses(jint class_count,
1.64 + const jvmtiClassDefinition *class_defs,
1.65 + JvmtiClassLoadKind class_load_kind) {
1.66 + _class_count = class_count;
1.67 + _class_defs = class_defs;
1.68 + _class_load_kind = class_load_kind;
1.69 + _res = JVMTI_ERROR_NONE;
1.70 +}
1.71 +
1.72 +bool VM_RedefineClasses::doit_prologue() {
1.73 + if (_class_count == 0) {
1.74 + _res = JVMTI_ERROR_NONE;
1.75 + return false;
1.76 + }
1.77 + if (_class_defs == NULL) {
1.78 + _res = JVMTI_ERROR_NULL_POINTER;
1.79 + return false;
1.80 + }
1.81 + for (int i = 0; i < _class_count; i++) {
1.82 + if (_class_defs[i].klass == NULL) {
1.83 + _res = JVMTI_ERROR_INVALID_CLASS;
1.84 + return false;
1.85 + }
1.86 + if (_class_defs[i].class_byte_count == 0) {
1.87 + _res = JVMTI_ERROR_INVALID_CLASS_FORMAT;
1.88 + return false;
1.89 + }
1.90 + if (_class_defs[i].class_bytes == NULL) {
1.91 + _res = JVMTI_ERROR_NULL_POINTER;
1.92 + return false;
1.93 + }
1.94 + }
1.95 +
1.96 + // Start timer after all the sanity checks; not quite accurate, but
1.97 + // better than adding a bunch of stop() calls.
1.98 + RC_TIMER_START(_timer_vm_op_prologue);
1.99 +
1.100 + // We first load new class versions in the prologue, because somewhere down the
1.101 + // call chain it is required that the current thread is a Java thread.
1.102 + _res = load_new_class_versions(Thread::current());
1.103 + if (_res != JVMTI_ERROR_NONE) {
1.104 + // free any successfully created classes, since none are redefined
1.105 + for (int i = 0; i < _class_count; i++) {
1.106 + if (_scratch_classes[i] != NULL) {
1.107 + ClassLoaderData* cld = _scratch_classes[i]->class_loader_data();
1.108 + // Free the memory for this class at class unloading time. Not before
1.109 + // because CMS might think this is still live.
1.110 + cld->add_to_deallocate_list((InstanceKlass*)_scratch_classes[i]);
1.111 + }
1.112 + }
1.113 + // Free os::malloc allocated memory in load_new_class_version.
1.114 + os::free(_scratch_classes);
1.115 + RC_TIMER_STOP(_timer_vm_op_prologue);
1.116 + return false;
1.117 + }
1.118 +
1.119 + RC_TIMER_STOP(_timer_vm_op_prologue);
1.120 + return true;
1.121 +}
1.122 +
1.123 +void VM_RedefineClasses::doit() {
1.124 + Thread *thread = Thread::current();
1.125 +
1.126 + if (UseSharedSpaces) {
1.127 + // Sharing is enabled so we remap the shared readonly space to
1.128 + // shared readwrite, private just in case we need to redefine
1.129 + // a shared class. We do the remap during the doit() phase of
1.130 + // the safepoint to be safer.
1.131 + if (!MetaspaceShared::remap_shared_readonly_as_readwrite()) {
1.132 + RC_TRACE_WITH_THREAD(0x00000001, thread,
1.133 + ("failed to remap shared readonly space to readwrite, private"));
1.134 + _res = JVMTI_ERROR_INTERNAL;
1.135 + return;
1.136 + }
1.137 + }
1.138 +
1.139 + // Mark methods seen on stack and everywhere else so old methods are not
1.140 + // cleaned up if they're on the stack.
1.141 + MetadataOnStackMark md_on_stack;
1.142 + HandleMark hm(thread); // make sure any handles created are deleted
1.143 + // before the stack walk again.
1.144 +
1.145 + for (int i = 0; i < _class_count; i++) {
1.146 + redefine_single_class(_class_defs[i].klass, _scratch_classes[i], thread);
1.147 + ClassLoaderData* cld = _scratch_classes[i]->class_loader_data();
1.148 + // Free the memory for this class at class unloading time. Not before
1.149 + // because CMS might think this is still live.
1.150 + cld->add_to_deallocate_list((InstanceKlass*)_scratch_classes[i]);
1.151 + _scratch_classes[i] = NULL;
1.152 + }
1.153 +
1.154 + // Disable any dependent concurrent compilations
1.155 + SystemDictionary::notice_modification();
1.156 +
1.157 + // Set flag indicating that some invariants are no longer true.
1.158 + // See jvmtiExport.hpp for detailed explanation.
1.159 + JvmtiExport::set_has_redefined_a_class();
1.160 +
1.161 +// check_class() is optionally called for product bits, but is
1.162 +// always called for non-product bits.
1.163 +#ifdef PRODUCT
1.164 + if (RC_TRACE_ENABLED(0x00004000)) {
1.165 +#endif
1.166 + RC_TRACE_WITH_THREAD(0x00004000, thread, ("calling check_class"));
1.167 + CheckClass check_class(thread);
1.168 + ClassLoaderDataGraph::classes_do(&check_class);
1.169 +#ifdef PRODUCT
1.170 + }
1.171 +#endif
1.172 +}
1.173 +
1.174 +void VM_RedefineClasses::doit_epilogue() {
1.175 + // Free os::malloc allocated memory.
1.176 + os::free(_scratch_classes);
1.177 +
1.178 + if (RC_TRACE_ENABLED(0x00000004)) {
1.179 + // Used to have separate timers for "doit" and "all", but the timer
1.180 + // overhead skewed the measurements.
1.181 + jlong doit_time = _timer_rsc_phase1.milliseconds() +
1.182 + _timer_rsc_phase2.milliseconds();
1.183 + jlong all_time = _timer_vm_op_prologue.milliseconds() + doit_time;
1.184 +
1.185 + RC_TRACE(0x00000004, ("vm_op: all=" UINT64_FORMAT
1.186 + " prologue=" UINT64_FORMAT " doit=" UINT64_FORMAT, all_time,
1.187 + _timer_vm_op_prologue.milliseconds(), doit_time));
1.188 + RC_TRACE(0x00000004,
1.189 + ("redefine_single_class: phase1=" UINT64_FORMAT " phase2=" UINT64_FORMAT,
1.190 + _timer_rsc_phase1.milliseconds(), _timer_rsc_phase2.milliseconds()));
1.191 + }
1.192 +}
1.193 +
1.194 +bool VM_RedefineClasses::is_modifiable_class(oop klass_mirror) {
1.195 + // classes for primitives cannot be redefined
1.196 + if (java_lang_Class::is_primitive(klass_mirror)) {
1.197 + return false;
1.198 + }
1.199 + Klass* the_class_oop = java_lang_Class::as_Klass(klass_mirror);
1.200 + // classes for arrays cannot be redefined
1.201 + if (the_class_oop == NULL || !the_class_oop->oop_is_instance()) {
1.202 + return false;
1.203 + }
1.204 + return true;
1.205 +}
1.206 +
1.207 +// Append the current entry at scratch_i in scratch_cp to *merge_cp_p
1.208 +// where the end of *merge_cp_p is specified by *merge_cp_length_p. For
1.209 +// direct CP entries, there is just the current entry to append. For
1.210 +// indirect and double-indirect CP entries, there are zero or more
1.211 +// referenced CP entries along with the current entry to append.
1.212 +// Indirect and double-indirect CP entries are handled by recursive
1.213 +// calls to append_entry() as needed. The referenced CP entries are
1.214 +// always appended to *merge_cp_p before the referee CP entry. These
1.215 +// referenced CP entries may already exist in *merge_cp_p in which case
1.216 +// there is nothing extra to append and only the current entry is
1.217 +// appended.
1.218 +void VM_RedefineClasses::append_entry(constantPoolHandle scratch_cp,
1.219 + int scratch_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p,
1.220 + TRAPS) {
1.221 +
1.222 + // append is different depending on entry tag type
1.223 + switch (scratch_cp->tag_at(scratch_i).value()) {
1.224 +
1.225 + // The old verifier is implemented outside the VM. It loads classes,
1.226 + // but does not resolve constant pool entries directly so we never
1.227 + // see Class entries here with the old verifier. Similarly the old
1.228 + // verifier does not like Class entries in the input constant pool.
1.229 + // The split-verifier is implemented in the VM so it can optionally
1.230 + // and directly resolve constant pool entries to load classes. The
1.231 + // split-verifier can accept either Class entries or UnresolvedClass
1.232 + // entries in the input constant pool. We revert the appended copy
1.233 + // back to UnresolvedClass so that either verifier will be happy
1.234 + // with the constant pool entry.
1.235 + case JVM_CONSTANT_Class:
1.236 + {
1.237 + // revert the copy to JVM_CONSTANT_UnresolvedClass
1.238 + (*merge_cp_p)->unresolved_klass_at_put(*merge_cp_length_p,
1.239 + scratch_cp->klass_name_at(scratch_i));
1.240 +
1.241 + if (scratch_i != *merge_cp_length_p) {
1.242 + // The new entry in *merge_cp_p is at a different index than
1.243 + // the new entry in scratch_cp so we need to map the index values.
1.244 + map_index(scratch_cp, scratch_i, *merge_cp_length_p);
1.245 + }
1.246 + (*merge_cp_length_p)++;
1.247 + } break;
1.248 +
1.249 + // these are direct CP entries so they can be directly appended,
1.250 + // but double and long take two constant pool entries
1.251 + case JVM_CONSTANT_Double: // fall through
1.252 + case JVM_CONSTANT_Long:
1.253 + {
1.254 + ConstantPool::copy_entry_to(scratch_cp, scratch_i, *merge_cp_p, *merge_cp_length_p,
1.255 + THREAD);
1.256 +
1.257 + if (scratch_i != *merge_cp_length_p) {
1.258 + // The new entry in *merge_cp_p is at a different index than
1.259 + // the new entry in scratch_cp so we need to map the index values.
1.260 + map_index(scratch_cp, scratch_i, *merge_cp_length_p);
1.261 + }
1.262 + (*merge_cp_length_p) += 2;
1.263 + } break;
1.264 +
1.265 + // these are direct CP entries so they can be directly appended
1.266 + case JVM_CONSTANT_Float: // fall through
1.267 + case JVM_CONSTANT_Integer: // fall through
1.268 + case JVM_CONSTANT_Utf8: // fall through
1.269 +
1.270 + // This was an indirect CP entry, but it has been changed into
1.271 + // Symbol*s so this entry can be directly appended.
1.272 + case JVM_CONSTANT_String: // fall through
1.273 +
1.274 + // These were indirect CP entries, but they have been changed into
1.275 + // Symbol*s so these entries can be directly appended.
1.276 + case JVM_CONSTANT_UnresolvedClass: // fall through
1.277 + {
1.278 + ConstantPool::copy_entry_to(scratch_cp, scratch_i, *merge_cp_p, *merge_cp_length_p,
1.279 + THREAD);
1.280 +
1.281 + if (scratch_i != *merge_cp_length_p) {
1.282 + // The new entry in *merge_cp_p is at a different index than
1.283 + // the new entry in scratch_cp so we need to map the index values.
1.284 + map_index(scratch_cp, scratch_i, *merge_cp_length_p);
1.285 + }
1.286 + (*merge_cp_length_p)++;
1.287 + } break;
1.288 +
1.289 + // this is an indirect CP entry so it needs special handling
1.290 + case JVM_CONSTANT_NameAndType:
1.291 + {
1.292 + int name_ref_i = scratch_cp->name_ref_index_at(scratch_i);
1.293 + int new_name_ref_i = find_or_append_indirect_entry(scratch_cp, name_ref_i, merge_cp_p,
1.294 + merge_cp_length_p, THREAD);
1.295 +
1.296 + int signature_ref_i = scratch_cp->signature_ref_index_at(scratch_i);
1.297 + int new_signature_ref_i = find_or_append_indirect_entry(scratch_cp, signature_ref_i,
1.298 + merge_cp_p, merge_cp_length_p,
1.299 + THREAD);
1.300 +
1.301 + // If the referenced entries already exist in *merge_cp_p, then
1.302 + // both new_name_ref_i and new_signature_ref_i will both be 0.
1.303 + // In that case, all we are appending is the current entry.
1.304 + if (new_name_ref_i != name_ref_i) {
1.305 + RC_TRACE(0x00080000,
1.306 + ("NameAndType entry@%d name_ref_index change: %d to %d",
1.307 + *merge_cp_length_p, name_ref_i, new_name_ref_i));
1.308 + }
1.309 + if (new_signature_ref_i != signature_ref_i) {
1.310 + RC_TRACE(0x00080000,
1.311 + ("NameAndType entry@%d signature_ref_index change: %d to %d",
1.312 + *merge_cp_length_p, signature_ref_i, new_signature_ref_i));
1.313 + }
1.314 +
1.315 + (*merge_cp_p)->name_and_type_at_put(*merge_cp_length_p,
1.316 + new_name_ref_i, new_signature_ref_i);
1.317 + if (scratch_i != *merge_cp_length_p) {
1.318 + // The new entry in *merge_cp_p is at a different index than
1.319 + // the new entry in scratch_cp so we need to map the index values.
1.320 + map_index(scratch_cp, scratch_i, *merge_cp_length_p);
1.321 + }
1.322 + (*merge_cp_length_p)++;
1.323 + } break;
1.324 +
1.325 + // this is a double-indirect CP entry so it needs special handling
1.326 + case JVM_CONSTANT_Fieldref: // fall through
1.327 + case JVM_CONSTANT_InterfaceMethodref: // fall through
1.328 + case JVM_CONSTANT_Methodref:
1.329 + {
1.330 + int klass_ref_i = scratch_cp->uncached_klass_ref_index_at(scratch_i);
1.331 + int new_klass_ref_i = find_or_append_indirect_entry(scratch_cp, klass_ref_i,
1.332 + merge_cp_p, merge_cp_length_p, THREAD);
1.333 +
1.334 + int name_and_type_ref_i = scratch_cp->uncached_name_and_type_ref_index_at(scratch_i);
1.335 + int new_name_and_type_ref_i = find_or_append_indirect_entry(scratch_cp, name_and_type_ref_i,
1.336 + merge_cp_p, merge_cp_length_p, THREAD);
1.337 +
1.338 + const char *entry_name;
1.339 + switch (scratch_cp->tag_at(scratch_i).value()) {
1.340 + case JVM_CONSTANT_Fieldref:
1.341 + entry_name = "Fieldref";
1.342 + (*merge_cp_p)->field_at_put(*merge_cp_length_p, new_klass_ref_i,
1.343 + new_name_and_type_ref_i);
1.344 + break;
1.345 + case JVM_CONSTANT_InterfaceMethodref:
1.346 + entry_name = "IFMethodref";
1.347 + (*merge_cp_p)->interface_method_at_put(*merge_cp_length_p,
1.348 + new_klass_ref_i, new_name_and_type_ref_i);
1.349 + break;
1.350 + case JVM_CONSTANT_Methodref:
1.351 + entry_name = "Methodref";
1.352 + (*merge_cp_p)->method_at_put(*merge_cp_length_p, new_klass_ref_i,
1.353 + new_name_and_type_ref_i);
1.354 + break;
1.355 + default:
1.356 + guarantee(false, "bad switch");
1.357 + break;
1.358 + }
1.359 +
1.360 + if (klass_ref_i != new_klass_ref_i) {
1.361 + RC_TRACE(0x00080000, ("%s entry@%d class_index changed: %d to %d",
1.362 + entry_name, *merge_cp_length_p, klass_ref_i, new_klass_ref_i));
1.363 + }
1.364 + if (name_and_type_ref_i != new_name_and_type_ref_i) {
1.365 + RC_TRACE(0x00080000,
1.366 + ("%s entry@%d name_and_type_index changed: %d to %d",
1.367 + entry_name, *merge_cp_length_p, name_and_type_ref_i,
1.368 + new_name_and_type_ref_i));
1.369 + }
1.370 +
1.371 + if (scratch_i != *merge_cp_length_p) {
1.372 + // The new entry in *merge_cp_p is at a different index than
1.373 + // the new entry in scratch_cp so we need to map the index values.
1.374 + map_index(scratch_cp, scratch_i, *merge_cp_length_p);
1.375 + }
1.376 + (*merge_cp_length_p)++;
1.377 + } break;
1.378 +
1.379 + // this is an indirect CP entry so it needs special handling
1.380 + case JVM_CONSTANT_MethodType:
1.381 + {
1.382 + int ref_i = scratch_cp->method_type_index_at(scratch_i);
1.383 + int new_ref_i = find_or_append_indirect_entry(scratch_cp, ref_i, merge_cp_p,
1.384 + merge_cp_length_p, THREAD);
1.385 + if (new_ref_i != ref_i) {
1.386 + RC_TRACE(0x00080000,
1.387 + ("MethodType entry@%d ref_index change: %d to %d",
1.388 + *merge_cp_length_p, ref_i, new_ref_i));
1.389 + }
1.390 + (*merge_cp_p)->method_type_index_at_put(*merge_cp_length_p, new_ref_i);
1.391 + if (scratch_i != *merge_cp_length_p) {
1.392 + // The new entry in *merge_cp_p is at a different index than
1.393 + // the new entry in scratch_cp so we need to map the index values.
1.394 + map_index(scratch_cp, scratch_i, *merge_cp_length_p);
1.395 + }
1.396 + (*merge_cp_length_p)++;
1.397 + } break;
1.398 +
1.399 + // this is an indirect CP entry so it needs special handling
1.400 + case JVM_CONSTANT_MethodHandle:
1.401 + {
1.402 + int ref_kind = scratch_cp->method_handle_ref_kind_at(scratch_i);
1.403 + int ref_i = scratch_cp->method_handle_index_at(scratch_i);
1.404 + int new_ref_i = find_or_append_indirect_entry(scratch_cp, ref_i, merge_cp_p,
1.405 + merge_cp_length_p, THREAD);
1.406 + if (new_ref_i != ref_i) {
1.407 + RC_TRACE(0x00080000,
1.408 + ("MethodHandle entry@%d ref_index change: %d to %d",
1.409 + *merge_cp_length_p, ref_i, new_ref_i));
1.410 + }
1.411 + (*merge_cp_p)->method_handle_index_at_put(*merge_cp_length_p, ref_kind, new_ref_i);
1.412 + if (scratch_i != *merge_cp_length_p) {
1.413 + // The new entry in *merge_cp_p is at a different index than
1.414 + // the new entry in scratch_cp so we need to map the index values.
1.415 + map_index(scratch_cp, scratch_i, *merge_cp_length_p);
1.416 + }
1.417 + (*merge_cp_length_p)++;
1.418 + } break;
1.419 +
1.420 + // this is an indirect CP entry so it needs special handling
1.421 + case JVM_CONSTANT_InvokeDynamic:
1.422 + {
1.423 + // Index of the bootstrap specifier in the operands array
1.424 + int old_bs_i = scratch_cp->invoke_dynamic_bootstrap_specifier_index(scratch_i);
1.425 + int new_bs_i = find_or_append_operand(scratch_cp, old_bs_i, merge_cp_p,
1.426 + merge_cp_length_p, THREAD);
1.427 + // The bootstrap method NameAndType_info index
1.428 + int old_ref_i = scratch_cp->invoke_dynamic_name_and_type_ref_index_at(scratch_i);
1.429 + int new_ref_i = find_or_append_indirect_entry(scratch_cp, old_ref_i, merge_cp_p,
1.430 + merge_cp_length_p, THREAD);
1.431 + if (new_bs_i != old_bs_i) {
1.432 + RC_TRACE(0x00080000,
1.433 + ("InvokeDynamic entry@%d bootstrap_method_attr_index change: %d to %d",
1.434 + *merge_cp_length_p, old_bs_i, new_bs_i));
1.435 + }
1.436 + if (new_ref_i != old_ref_i) {
1.437 + RC_TRACE(0x00080000,
1.438 + ("InvokeDynamic entry@%d name_and_type_index change: %d to %d",
1.439 + *merge_cp_length_p, old_ref_i, new_ref_i));
1.440 + }
1.441 +
1.442 + (*merge_cp_p)->invoke_dynamic_at_put(*merge_cp_length_p, new_bs_i, new_ref_i);
1.443 + if (scratch_i != *merge_cp_length_p) {
1.444 + // The new entry in *merge_cp_p is at a different index than
1.445 + // the new entry in scratch_cp so we need to map the index values.
1.446 + map_index(scratch_cp, scratch_i, *merge_cp_length_p);
1.447 + }
1.448 + (*merge_cp_length_p)++;
1.449 + } break;
1.450 +
1.451 + // At this stage, Class or UnresolvedClass could be here, but not
1.452 + // ClassIndex
1.453 + case JVM_CONSTANT_ClassIndex: // fall through
1.454 +
1.455 + // Invalid is used as the tag for the second constant pool entry
1.456 + // occupied by JVM_CONSTANT_Double or JVM_CONSTANT_Long. It should
1.457 + // not be seen by itself.
1.458 + case JVM_CONSTANT_Invalid: // fall through
1.459 +
1.460 + // At this stage, String could be here, but not StringIndex
1.461 + case JVM_CONSTANT_StringIndex: // fall through
1.462 +
1.463 + // At this stage JVM_CONSTANT_UnresolvedClassInError should not be
1.464 + // here
1.465 + case JVM_CONSTANT_UnresolvedClassInError: // fall through
1.466 +
1.467 + default:
1.468 + {
1.469 + // leave a breadcrumb
1.470 + jbyte bad_value = scratch_cp->tag_at(scratch_i).value();
1.471 + ShouldNotReachHere();
1.472 + } break;
1.473 + } // end switch tag value
1.474 +} // end append_entry()
1.475 +
1.476 +
1.477 +int VM_RedefineClasses::find_or_append_indirect_entry(constantPoolHandle scratch_cp,
1.478 + int ref_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p, TRAPS) {
1.479 +
1.480 + int new_ref_i = ref_i;
1.481 + bool match = (ref_i < *merge_cp_length_p) &&
1.482 + scratch_cp->compare_entry_to(ref_i, *merge_cp_p, ref_i, THREAD);
1.483 +
1.484 + if (!match) {
1.485 + // forward reference in *merge_cp_p or not a direct match
1.486 + int found_i = scratch_cp->find_matching_entry(ref_i, *merge_cp_p, THREAD);
1.487 + if (found_i != 0) {
1.488 + guarantee(found_i != ref_i, "compare_entry_to() and find_matching_entry() do not agree");
1.489 + // Found a matching entry somewhere else in *merge_cp_p so just need a mapping entry.
1.490 + new_ref_i = found_i;
1.491 + map_index(scratch_cp, ref_i, found_i);
1.492 + } else {
1.493 + // no match found so we have to append this entry to *merge_cp_p
1.494 + append_entry(scratch_cp, ref_i, merge_cp_p, merge_cp_length_p, THREAD);
1.495 + // The above call to append_entry() can only append one entry
1.496 + // so the post call query of *merge_cp_length_p is only for
1.497 + // the sake of consistency.
1.498 + new_ref_i = *merge_cp_length_p - 1;
1.499 + }
1.500 + }
1.501 +
1.502 + return new_ref_i;
1.503 +} // end find_or_append_indirect_entry()
1.504 +
1.505 +
1.506 +// Append a bootstrap specifier into the merge_cp operands that is semantically equal
1.507 +// to the scratch_cp operands bootstrap specifier passed by the old_bs_i index.
1.508 +// Recursively append new merge_cp entries referenced by the new bootstrap specifier.
1.509 +void VM_RedefineClasses::append_operand(constantPoolHandle scratch_cp, int old_bs_i,
1.510 + constantPoolHandle *merge_cp_p, int *merge_cp_length_p, TRAPS) {
1.511 +
1.512 + int old_ref_i = scratch_cp->operand_bootstrap_method_ref_index_at(old_bs_i);
1.513 + int new_ref_i = find_or_append_indirect_entry(scratch_cp, old_ref_i, merge_cp_p,
1.514 + merge_cp_length_p, THREAD);
1.515 + if (new_ref_i != old_ref_i) {
1.516 + RC_TRACE(0x00080000,
1.517 + ("operands entry@%d bootstrap method ref_index change: %d to %d",
1.518 + _operands_cur_length, old_ref_i, new_ref_i));
1.519 + }
1.520 +
1.521 + Array<u2>* merge_ops = (*merge_cp_p)->operands();
1.522 + int new_bs_i = _operands_cur_length;
1.523 + // We have _operands_cur_length == 0 when the merge_cp operands is empty yet.
1.524 + // However, the operand_offset_at(0) was set in the extend_operands() call.
1.525 + int new_base = (new_bs_i == 0) ? (*merge_cp_p)->operand_offset_at(0)
1.526 + : (*merge_cp_p)->operand_next_offset_at(new_bs_i - 1);
1.527 + int argc = scratch_cp->operand_argument_count_at(old_bs_i);
1.528 +
1.529 + ConstantPool::operand_offset_at_put(merge_ops, _operands_cur_length, new_base);
1.530 + merge_ops->at_put(new_base++, new_ref_i);
1.531 + merge_ops->at_put(new_base++, argc);
1.532 +
1.533 + for (int i = 0; i < argc; i++) {
1.534 + int old_arg_ref_i = scratch_cp->operand_argument_index_at(old_bs_i, i);
1.535 + int new_arg_ref_i = find_or_append_indirect_entry(scratch_cp, old_arg_ref_i, merge_cp_p,
1.536 + merge_cp_length_p, THREAD);
1.537 + merge_ops->at_put(new_base++, new_arg_ref_i);
1.538 + if (new_arg_ref_i != old_arg_ref_i) {
1.539 + RC_TRACE(0x00080000,
1.540 + ("operands entry@%d bootstrap method argument ref_index change: %d to %d",
1.541 + _operands_cur_length, old_arg_ref_i, new_arg_ref_i));
1.542 + }
1.543 + }
1.544 + if (old_bs_i != _operands_cur_length) {
1.545 + // The bootstrap specifier in *merge_cp_p is at a different index than
1.546 + // that in scratch_cp so we need to map the index values.
1.547 + map_operand_index(old_bs_i, new_bs_i);
1.548 + }
1.549 + _operands_cur_length++;
1.550 +} // end append_operand()
1.551 +
1.552 +
1.553 +int VM_RedefineClasses::find_or_append_operand(constantPoolHandle scratch_cp,
1.554 + int old_bs_i, constantPoolHandle *merge_cp_p, int *merge_cp_length_p, TRAPS) {
1.555 +
1.556 + int new_bs_i = old_bs_i; // bootstrap specifier index
1.557 + bool match = (old_bs_i < _operands_cur_length) &&
1.558 + scratch_cp->compare_operand_to(old_bs_i, *merge_cp_p, old_bs_i, THREAD);
1.559 +
1.560 + if (!match) {
1.561 + // forward reference in *merge_cp_p or not a direct match
1.562 + int found_i = scratch_cp->find_matching_operand(old_bs_i, *merge_cp_p,
1.563 + _operands_cur_length, THREAD);
1.564 + if (found_i != -1) {
1.565 + guarantee(found_i != old_bs_i, "compare_operand_to() and find_matching_operand() disagree");
1.566 + // found a matching operand somewhere else in *merge_cp_p so just need a mapping
1.567 + new_bs_i = found_i;
1.568 + map_operand_index(old_bs_i, found_i);
1.569 + } else {
1.570 + // no match found so we have to append this bootstrap specifier to *merge_cp_p
1.571 + append_operand(scratch_cp, old_bs_i, merge_cp_p, merge_cp_length_p, THREAD);
1.572 + new_bs_i = _operands_cur_length - 1;
1.573 + }
1.574 + }
1.575 + return new_bs_i;
1.576 +} // end find_or_append_operand()
1.577 +
1.578 +
1.579 +void VM_RedefineClasses::finalize_operands_merge(constantPoolHandle merge_cp, TRAPS) {
1.580 + if (merge_cp->operands() == NULL) {
1.581 + return;
1.582 + }
1.583 + // Shrink the merge_cp operands
1.584 + merge_cp->shrink_operands(_operands_cur_length, CHECK);
1.585 +
1.586 + if (RC_TRACE_ENABLED(0x00040000)) {
1.587 + // don't want to loop unless we are tracing
1.588 + int count = 0;
1.589 + for (int i = 1; i < _operands_index_map_p->length(); i++) {
1.590 + int value = _operands_index_map_p->at(i);
1.591 + if (value != -1) {
1.592 + RC_TRACE_WITH_THREAD(0x00040000, THREAD,
1.593 + ("operands_index_map[%d]: old=%d new=%d", count, i, value));
1.594 + count++;
1.595 + }
1.596 + }
1.597 + }
1.598 + // Clean-up
1.599 + _operands_index_map_p = NULL;
1.600 + _operands_cur_length = 0;
1.601 + _operands_index_map_count = 0;
1.602 +} // end finalize_operands_merge()
1.603 +
1.604 +
1.605 +jvmtiError VM_RedefineClasses::compare_and_normalize_class_versions(
1.606 + instanceKlassHandle the_class,
1.607 + instanceKlassHandle scratch_class) {
1.608 + int i;
1.609 +
1.610 + // Check superclasses, or rather their names, since superclasses themselves can be
1.611 + // requested to replace.
1.612 + // Check for NULL superclass first since this might be java.lang.Object
1.613 + if (the_class->super() != scratch_class->super() &&
1.614 + (the_class->super() == NULL || scratch_class->super() == NULL ||
1.615 + the_class->super()->name() !=
1.616 + scratch_class->super()->name())) {
1.617 + return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
1.618 + }
1.619 +
1.620 + // Check if the number, names and order of directly implemented interfaces are the same.
1.621 + // I think in principle we should just check if the sets of names of directly implemented
1.622 + // interfaces are the same, i.e. the order of declaration (which, however, if changed in the
1.623 + // .java file, also changes in .class file) should not matter. However, comparing sets is
1.624 + // technically a bit more difficult, and, more importantly, I am not sure at present that the
1.625 + // order of interfaces does not matter on the implementation level, i.e. that the VM does not
1.626 + // rely on it somewhere.
1.627 + Array<Klass*>* k_interfaces = the_class->local_interfaces();
1.628 + Array<Klass*>* k_new_interfaces = scratch_class->local_interfaces();
1.629 + int n_intfs = k_interfaces->length();
1.630 + if (n_intfs != k_new_interfaces->length()) {
1.631 + return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
1.632 + }
1.633 + for (i = 0; i < n_intfs; i++) {
1.634 + if (k_interfaces->at(i)->name() !=
1.635 + k_new_interfaces->at(i)->name()) {
1.636 + return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_HIERARCHY_CHANGED;
1.637 + }
1.638 + }
1.639 +
1.640 + // Check whether class is in the error init state.
1.641 + if (the_class->is_in_error_state()) {
1.642 + // TBD #5057930: special error code is needed in 1.6
1.643 + return JVMTI_ERROR_INVALID_CLASS;
1.644 + }
1.645 +
1.646 + // Check whether class modifiers are the same.
1.647 + jushort old_flags = (jushort) the_class->access_flags().get_flags();
1.648 + jushort new_flags = (jushort) scratch_class->access_flags().get_flags();
1.649 + if (old_flags != new_flags) {
1.650 + return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_CLASS_MODIFIERS_CHANGED;
1.651 + }
1.652 +
1.653 + // Check if the number, names, types and order of fields declared in these classes
1.654 + // are the same.
1.655 + JavaFieldStream old_fs(the_class);
1.656 + JavaFieldStream new_fs(scratch_class);
1.657 + for (; !old_fs.done() && !new_fs.done(); old_fs.next(), new_fs.next()) {
1.658 + // access
1.659 + old_flags = old_fs.access_flags().as_short();
1.660 + new_flags = new_fs.access_flags().as_short();
1.661 + if ((old_flags ^ new_flags) & JVM_RECOGNIZED_FIELD_MODIFIERS) {
1.662 + return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
1.663 + }
1.664 + // offset
1.665 + if (old_fs.offset() != new_fs.offset()) {
1.666 + return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
1.667 + }
1.668 + // name and signature
1.669 + Symbol* name_sym1 = the_class->constants()->symbol_at(old_fs.name_index());
1.670 + Symbol* sig_sym1 = the_class->constants()->symbol_at(old_fs.signature_index());
1.671 + Symbol* name_sym2 = scratch_class->constants()->symbol_at(new_fs.name_index());
1.672 + Symbol* sig_sym2 = scratch_class->constants()->symbol_at(new_fs.signature_index());
1.673 + if (name_sym1 != name_sym2 || sig_sym1 != sig_sym2) {
1.674 + return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
1.675 + }
1.676 + }
1.677 +
1.678 + // If both streams aren't done then we have a differing number of
1.679 + // fields.
1.680 + if (!old_fs.done() || !new_fs.done()) {
1.681 + return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_SCHEMA_CHANGED;
1.682 + }
1.683 +
1.684 + // Do a parallel walk through the old and new methods. Detect
1.685 + // cases where they match (exist in both), have been added in
1.686 + // the new methods, or have been deleted (exist only in the
1.687 + // old methods). The class file parser places methods in order
1.688 + // by method name, but does not order overloaded methods by
1.689 + // signature. In order to determine what fate befell the methods,
1.690 + // this code places the overloaded new methods that have matching
1.691 + // old methods in the same order as the old methods and places
1.692 + // new overloaded methods at the end of overloaded methods of
1.693 + // that name. The code for this order normalization is adapted
1.694 + // from the algorithm used in InstanceKlass::find_method().
1.695 + // Since we are swapping out of order entries as we find them,
1.696 + // we only have to search forward through the overloaded methods.
1.697 + // Methods which are added and have the same name as an existing
1.698 + // method (but different signature) will be put at the end of
1.699 + // the methods with that name, and the name mismatch code will
1.700 + // handle them.
1.701 + Array<Method*>* k_old_methods(the_class->methods());
1.702 + Array<Method*>* k_new_methods(scratch_class->methods());
1.703 + int n_old_methods = k_old_methods->length();
1.704 + int n_new_methods = k_new_methods->length();
1.705 + Thread* thread = Thread::current();
1.706 +
1.707 + int ni = 0;
1.708 + int oi = 0;
1.709 + while (true) {
1.710 + Method* k_old_method;
1.711 + Method* k_new_method;
1.712 + enum { matched, added, deleted, undetermined } method_was = undetermined;
1.713 +
1.714 + if (oi >= n_old_methods) {
1.715 + if (ni >= n_new_methods) {
1.716 + break; // we've looked at everything, done
1.717 + }
1.718 + // New method at the end
1.719 + k_new_method = k_new_methods->at(ni);
1.720 + method_was = added;
1.721 + } else if (ni >= n_new_methods) {
1.722 + // Old method, at the end, is deleted
1.723 + k_old_method = k_old_methods->at(oi);
1.724 + method_was = deleted;
1.725 + } else {
1.726 + // There are more methods in both the old and new lists
1.727 + k_old_method = k_old_methods->at(oi);
1.728 + k_new_method = k_new_methods->at(ni);
1.729 + if (k_old_method->name() != k_new_method->name()) {
1.730 + // Methods are sorted by method name, so a mismatch means added
1.731 + // or deleted
1.732 + if (k_old_method->name()->fast_compare(k_new_method->name()) > 0) {
1.733 + method_was = added;
1.734 + } else {
1.735 + method_was = deleted;
1.736 + }
1.737 + } else if (k_old_method->signature() == k_new_method->signature()) {
1.738 + // Both the name and signature match
1.739 + method_was = matched;
1.740 + } else {
1.741 + // The name matches, but the signature doesn't, which means we have to
1.742 + // search forward through the new overloaded methods.
1.743 + int nj; // outside the loop for post-loop check
1.744 + for (nj = ni + 1; nj < n_new_methods; nj++) {
1.745 + Method* m = k_new_methods->at(nj);
1.746 + if (k_old_method->name() != m->name()) {
1.747 + // reached another method name so no more overloaded methods
1.748 + method_was = deleted;
1.749 + break;
1.750 + }
1.751 + if (k_old_method->signature() == m->signature()) {
1.752 + // found a match so swap the methods
1.753 + k_new_methods->at_put(ni, m);
1.754 + k_new_methods->at_put(nj, k_new_method);
1.755 + k_new_method = m;
1.756 + method_was = matched;
1.757 + break;
1.758 + }
1.759 + }
1.760 +
1.761 + if (nj >= n_new_methods) {
1.762 + // reached the end without a match; so method was deleted
1.763 + method_was = deleted;
1.764 + }
1.765 + }
1.766 + }
1.767 +
1.768 + switch (method_was) {
1.769 + case matched:
1.770 + // methods match, be sure modifiers do too
1.771 + old_flags = (jushort) k_old_method->access_flags().get_flags();
1.772 + new_flags = (jushort) k_new_method->access_flags().get_flags();
1.773 + if ((old_flags ^ new_flags) & ~(JVM_ACC_NATIVE)) {
1.774 + return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_MODIFIERS_CHANGED;
1.775 + }
1.776 + {
1.777 + u2 new_num = k_new_method->method_idnum();
1.778 + u2 old_num = k_old_method->method_idnum();
1.779 + if (new_num != old_num) {
1.780 + Method* idnum_owner = scratch_class->method_with_idnum(old_num);
1.781 + if (idnum_owner != NULL) {
1.782 + // There is already a method assigned this idnum -- switch them
1.783 + idnum_owner->set_method_idnum(new_num);
1.784 + }
1.785 + k_new_method->set_method_idnum(old_num);
1.786 + if (thread->has_pending_exception()) {
1.787 + return JVMTI_ERROR_OUT_OF_MEMORY;
1.788 + }
1.789 + }
1.790 + }
1.791 + RC_TRACE(0x00008000, ("Method matched: new: %s [%d] == old: %s [%d]",
1.792 + k_new_method->name_and_sig_as_C_string(), ni,
1.793 + k_old_method->name_and_sig_as_C_string(), oi));
1.794 + // advance to next pair of methods
1.795 + ++oi;
1.796 + ++ni;
1.797 + break;
1.798 + case added:
1.799 + // method added, see if it is OK
1.800 + new_flags = (jushort) k_new_method->access_flags().get_flags();
1.801 + if ((new_flags & JVM_ACC_PRIVATE) == 0
1.802 + // hack: private should be treated as final, but alas
1.803 + || (new_flags & (JVM_ACC_FINAL|JVM_ACC_STATIC)) == 0
1.804 + ) {
1.805 + // new methods must be private
1.806 + return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED;
1.807 + }
1.808 + {
1.809 + u2 num = the_class->next_method_idnum();
1.810 + if (num == ConstMethod::UNSET_IDNUM) {
1.811 + // cannot add any more methods
1.812 + return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_ADDED;
1.813 + }
1.814 + u2 new_num = k_new_method->method_idnum();
1.815 + Method* idnum_owner = scratch_class->method_with_idnum(num);
1.816 + if (idnum_owner != NULL) {
1.817 + // There is already a method assigned this idnum -- switch them
1.818 + idnum_owner->set_method_idnum(new_num);
1.819 + }
1.820 + k_new_method->set_method_idnum(num);
1.821 + if (thread->has_pending_exception()) {
1.822 + return JVMTI_ERROR_OUT_OF_MEMORY;
1.823 + }
1.824 + }
1.825 + RC_TRACE(0x00008000, ("Method added: new: %s [%d]",
1.826 + k_new_method->name_and_sig_as_C_string(), ni));
1.827 + ++ni; // advance to next new method
1.828 + break;
1.829 + case deleted:
1.830 + // method deleted, see if it is OK
1.831 + old_flags = (jushort) k_old_method->access_flags().get_flags();
1.832 + if ((old_flags & JVM_ACC_PRIVATE) == 0
1.833 + // hack: private should be treated as final, but alas
1.834 + || (old_flags & (JVM_ACC_FINAL|JVM_ACC_STATIC)) == 0
1.835 + ) {
1.836 + // deleted methods must be private
1.837 + return JVMTI_ERROR_UNSUPPORTED_REDEFINITION_METHOD_DELETED;
1.838 + }
1.839 + RC_TRACE(0x00008000, ("Method deleted: old: %s [%d]",
1.840 + k_old_method->name_and_sig_as_C_string(), oi));
1.841 + ++oi; // advance to next old method
1.842 + break;
1.843 + default:
1.844 + ShouldNotReachHere();
1.845 + }
1.846 + }
1.847 +
1.848 + return JVMTI_ERROR_NONE;
1.849 +}
1.850 +
1.851 +
1.852 +// Find new constant pool index value for old constant pool index value
1.853 +// by seaching the index map. Returns zero (0) if there is no mapped
1.854 +// value for the old constant pool index.
1.855 +int VM_RedefineClasses::find_new_index(int old_index) {
1.856 + if (_index_map_count == 0) {
1.857 + // map is empty so nothing can be found
1.858 + return 0;
1.859 + }
1.860 +
1.861 + if (old_index < 1 || old_index >= _index_map_p->length()) {
1.862 + // The old_index is out of range so it is not mapped. This should
1.863 + // not happen in regular constant pool merging use, but it can
1.864 + // happen if a corrupt annotation is processed.
1.865 + return 0;
1.866 + }
1.867 +
1.868 + int value = _index_map_p->at(old_index);
1.869 + if (value == -1) {
1.870 + // the old_index is not mapped
1.871 + return 0;
1.872 + }
1.873 +
1.874 + return value;
1.875 +} // end find_new_index()
1.876 +
1.877 +
1.878 +// Find new bootstrap specifier index value for old bootstrap specifier index
1.879 +// value by seaching the index map. Returns unused index (-1) if there is
1.880 +// no mapped value for the old bootstrap specifier index.
1.881 +int VM_RedefineClasses::find_new_operand_index(int old_index) {
1.882 + if (_operands_index_map_count == 0) {
1.883 + // map is empty so nothing can be found
1.884 + return -1;
1.885 + }
1.886 +
1.887 + if (old_index == -1 || old_index >= _operands_index_map_p->length()) {
1.888 + // The old_index is out of range so it is not mapped.
1.889 + // This should not happen in regular constant pool merging use.
1.890 + return -1;
1.891 + }
1.892 +
1.893 + int value = _operands_index_map_p->at(old_index);
1.894 + if (value == -1) {
1.895 + // the old_index is not mapped
1.896 + return -1;
1.897 + }
1.898 +
1.899 + return value;
1.900 +} // end find_new_operand_index()
1.901 +
1.902 +
1.903 +// Returns true if the current mismatch is due to a resolved/unresolved
1.904 +// class pair. Otherwise, returns false.
1.905 +bool VM_RedefineClasses::is_unresolved_class_mismatch(constantPoolHandle cp1,
1.906 + int index1, constantPoolHandle cp2, int index2) {
1.907 +
1.908 + jbyte t1 = cp1->tag_at(index1).value();
1.909 + if (t1 != JVM_CONSTANT_Class && t1 != JVM_CONSTANT_UnresolvedClass) {
1.910 + return false; // wrong entry type; not our special case
1.911 + }
1.912 +
1.913 + jbyte t2 = cp2->tag_at(index2).value();
1.914 + if (t2 != JVM_CONSTANT_Class && t2 != JVM_CONSTANT_UnresolvedClass) {
1.915 + return false; // wrong entry type; not our special case
1.916 + }
1.917 +
1.918 + if (t1 == t2) {
1.919 + return false; // not a mismatch; not our special case
1.920 + }
1.921 +
1.922 + char *s1 = cp1->klass_name_at(index1)->as_C_string();
1.923 + char *s2 = cp2->klass_name_at(index2)->as_C_string();
1.924 + if (strcmp(s1, s2) != 0) {
1.925 + return false; // strings don't match; not our special case
1.926 + }
1.927 +
1.928 + return true; // made it through the gauntlet; this is our special case
1.929 +} // end is_unresolved_class_mismatch()
1.930 +
1.931 +
1.932 +jvmtiError VM_RedefineClasses::load_new_class_versions(TRAPS) {
1.933 +
1.934 + // For consistency allocate memory using os::malloc wrapper.
1.935 + _scratch_classes = (Klass**)
1.936 + os::malloc(sizeof(Klass*) * _class_count, mtClass);
1.937 + if (_scratch_classes == NULL) {
1.938 + return JVMTI_ERROR_OUT_OF_MEMORY;
1.939 + }
1.940 + // Zero initialize the _scratch_classes array.
1.941 + for (int i = 0; i < _class_count; i++) {
1.942 + _scratch_classes[i] = NULL;
1.943 + }
1.944 +
1.945 + ResourceMark rm(THREAD);
1.946 +
1.947 + JvmtiThreadState *state = JvmtiThreadState::state_for(JavaThread::current());
1.948 + // state can only be NULL if the current thread is exiting which
1.949 + // should not happen since we're trying to do a RedefineClasses
1.950 + guarantee(state != NULL, "exiting thread calling load_new_class_versions");
1.951 + for (int i = 0; i < _class_count; i++) {
1.952 + // Create HandleMark so that any handles created while loading new class
1.953 + // versions are deleted. Constant pools are deallocated while merging
1.954 + // constant pools
1.955 + HandleMark hm(THREAD);
1.956 +
1.957 + oop mirror = JNIHandles::resolve_non_null(_class_defs[i].klass);
1.958 + // classes for primitives cannot be redefined
1.959 + if (!is_modifiable_class(mirror)) {
1.960 + return JVMTI_ERROR_UNMODIFIABLE_CLASS;
1.961 + }
1.962 + Klass* the_class_oop = java_lang_Class::as_Klass(mirror);
1.963 + instanceKlassHandle the_class = instanceKlassHandle(THREAD, the_class_oop);
1.964 + Symbol* the_class_sym = the_class->name();
1.965 +
1.966 + // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
1.967 + RC_TRACE_WITH_THREAD(0x00000001, THREAD,
1.968 + ("loading name=%s kind=%d (avail_mem=" UINT64_FORMAT "K)",
1.969 + the_class->external_name(), _class_load_kind,
1.970 + os::available_memory() >> 10));
1.971 +
1.972 + ClassFileStream st((u1*) _class_defs[i].class_bytes,
1.973 + _class_defs[i].class_byte_count, (char *)"__VM_RedefineClasses__");
1.974 +
1.975 + // Parse the stream.
1.976 + Handle the_class_loader(THREAD, the_class->class_loader());
1.977 + Handle protection_domain(THREAD, the_class->protection_domain());
1.978 + // Set redefined class handle in JvmtiThreadState class.
1.979 + // This redefined class is sent to agent event handler for class file
1.980 + // load hook event.
1.981 + state->set_class_being_redefined(&the_class, _class_load_kind);
1.982 +
1.983 + Klass* k = SystemDictionary::parse_stream(the_class_sym,
1.984 + the_class_loader,
1.985 + protection_domain,
1.986 + &st,
1.987 + THREAD);
1.988 + // Clear class_being_redefined just to be sure.
1.989 + state->clear_class_being_redefined();
1.990 +
1.991 + // TODO: if this is retransform, and nothing changed we can skip it
1.992 +
1.993 + instanceKlassHandle scratch_class (THREAD, k);
1.994 +
1.995 + // Need to clean up allocated InstanceKlass if there's an error so assign
1.996 + // the result here. Caller deallocates all the scratch classes in case of
1.997 + // an error.
1.998 + _scratch_classes[i] = k;
1.999 +
1.1000 + if (HAS_PENDING_EXCEPTION) {
1.1001 + Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1.1002 + // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
1.1003 + RC_TRACE_WITH_THREAD(0x00000002, THREAD, ("parse_stream exception: '%s'",
1.1004 + ex_name->as_C_string()));
1.1005 + CLEAR_PENDING_EXCEPTION;
1.1006 +
1.1007 + if (ex_name == vmSymbols::java_lang_UnsupportedClassVersionError()) {
1.1008 + return JVMTI_ERROR_UNSUPPORTED_VERSION;
1.1009 + } else if (ex_name == vmSymbols::java_lang_ClassFormatError()) {
1.1010 + return JVMTI_ERROR_INVALID_CLASS_FORMAT;
1.1011 + } else if (ex_name == vmSymbols::java_lang_ClassCircularityError()) {
1.1012 + return JVMTI_ERROR_CIRCULAR_CLASS_DEFINITION;
1.1013 + } else if (ex_name == vmSymbols::java_lang_NoClassDefFoundError()) {
1.1014 + // The message will be "XXX (wrong name: YYY)"
1.1015 + return JVMTI_ERROR_NAMES_DONT_MATCH;
1.1016 + } else if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1.1017 + return JVMTI_ERROR_OUT_OF_MEMORY;
1.1018 + } else { // Just in case more exceptions can be thrown..
1.1019 + return JVMTI_ERROR_FAILS_VERIFICATION;
1.1020 + }
1.1021 + }
1.1022 +
1.1023 + // Ensure class is linked before redefine
1.1024 + if (!the_class->is_linked()) {
1.1025 + the_class->link_class(THREAD);
1.1026 + if (HAS_PENDING_EXCEPTION) {
1.1027 + Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1.1028 + // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
1.1029 + RC_TRACE_WITH_THREAD(0x00000002, THREAD, ("link_class exception: '%s'",
1.1030 + ex_name->as_C_string()));
1.1031 + CLEAR_PENDING_EXCEPTION;
1.1032 + if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1.1033 + return JVMTI_ERROR_OUT_OF_MEMORY;
1.1034 + } else {
1.1035 + return JVMTI_ERROR_INTERNAL;
1.1036 + }
1.1037 + }
1.1038 + }
1.1039 +
1.1040 + // Do the validity checks in compare_and_normalize_class_versions()
1.1041 + // before verifying the byte codes. By doing these checks first, we
1.1042 + // limit the number of functions that require redirection from
1.1043 + // the_class to scratch_class. In particular, we don't have to
1.1044 + // modify JNI GetSuperclass() and thus won't change its performance.
1.1045 + jvmtiError res = compare_and_normalize_class_versions(the_class,
1.1046 + scratch_class);
1.1047 + if (res != JVMTI_ERROR_NONE) {
1.1048 + return res;
1.1049 + }
1.1050 +
1.1051 + // verify what the caller passed us
1.1052 + {
1.1053 + // The bug 6214132 caused the verification to fail.
1.1054 + // Information about the_class and scratch_class is temporarily
1.1055 + // recorded into jvmtiThreadState. This data is used to redirect
1.1056 + // the_class to scratch_class in the JVM_* functions called by the
1.1057 + // verifier. Please, refer to jvmtiThreadState.hpp for the detailed
1.1058 + // description.
1.1059 + RedefineVerifyMark rvm(&the_class, &scratch_class, state);
1.1060 + Verifier::verify(
1.1061 + scratch_class, Verifier::ThrowException, true, THREAD);
1.1062 + }
1.1063 +
1.1064 + if (HAS_PENDING_EXCEPTION) {
1.1065 + Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1.1066 + // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
1.1067 + RC_TRACE_WITH_THREAD(0x00000002, THREAD,
1.1068 + ("verify_byte_codes exception: '%s'", ex_name->as_C_string()));
1.1069 + CLEAR_PENDING_EXCEPTION;
1.1070 + if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1.1071 + return JVMTI_ERROR_OUT_OF_MEMORY;
1.1072 + } else {
1.1073 + // tell the caller the bytecodes are bad
1.1074 + return JVMTI_ERROR_FAILS_VERIFICATION;
1.1075 + }
1.1076 + }
1.1077 +
1.1078 + res = merge_cp_and_rewrite(the_class, scratch_class, THREAD);
1.1079 + if (HAS_PENDING_EXCEPTION) {
1.1080 + Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1.1081 + // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
1.1082 + RC_TRACE_WITH_THREAD(0x00000002, THREAD,
1.1083 + ("merge_cp_and_rewrite exception: '%s'", ex_name->as_C_string()));
1.1084 + CLEAR_PENDING_EXCEPTION;
1.1085 + if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1.1086 + return JVMTI_ERROR_OUT_OF_MEMORY;
1.1087 + } else {
1.1088 + return JVMTI_ERROR_INTERNAL;
1.1089 + }
1.1090 + }
1.1091 +
1.1092 + if (VerifyMergedCPBytecodes) {
1.1093 + // verify what we have done during constant pool merging
1.1094 + {
1.1095 + RedefineVerifyMark rvm(&the_class, &scratch_class, state);
1.1096 + Verifier::verify(scratch_class, Verifier::ThrowException, true, THREAD);
1.1097 + }
1.1098 +
1.1099 + if (HAS_PENDING_EXCEPTION) {
1.1100 + Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1.1101 + // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
1.1102 + RC_TRACE_WITH_THREAD(0x00000002, THREAD,
1.1103 + ("verify_byte_codes post merge-CP exception: '%s'",
1.1104 + ex_name->as_C_string()));
1.1105 + CLEAR_PENDING_EXCEPTION;
1.1106 + if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1.1107 + return JVMTI_ERROR_OUT_OF_MEMORY;
1.1108 + } else {
1.1109 + // tell the caller that constant pool merging screwed up
1.1110 + return JVMTI_ERROR_INTERNAL;
1.1111 + }
1.1112 + }
1.1113 + }
1.1114 +
1.1115 + Rewriter::rewrite(scratch_class, THREAD);
1.1116 + if (!HAS_PENDING_EXCEPTION) {
1.1117 + scratch_class->link_methods(THREAD);
1.1118 + }
1.1119 + if (HAS_PENDING_EXCEPTION) {
1.1120 + Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1.1121 + // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
1.1122 + RC_TRACE_WITH_THREAD(0x00000002, THREAD,
1.1123 + ("Rewriter::rewrite or link_methods exception: '%s'", ex_name->as_C_string()));
1.1124 + CLEAR_PENDING_EXCEPTION;
1.1125 + if (ex_name == vmSymbols::java_lang_OutOfMemoryError()) {
1.1126 + return JVMTI_ERROR_OUT_OF_MEMORY;
1.1127 + } else {
1.1128 + return JVMTI_ERROR_INTERNAL;
1.1129 + }
1.1130 + }
1.1131 +
1.1132 + // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
1.1133 + RC_TRACE_WITH_THREAD(0x00000001, THREAD,
1.1134 + ("loaded name=%s (avail_mem=" UINT64_FORMAT "K)",
1.1135 + the_class->external_name(), os::available_memory() >> 10));
1.1136 + }
1.1137 +
1.1138 + return JVMTI_ERROR_NONE;
1.1139 +}
1.1140 +
1.1141 +
1.1142 +// Map old_index to new_index as needed. scratch_cp is only needed
1.1143 +// for RC_TRACE() calls.
1.1144 +void VM_RedefineClasses::map_index(constantPoolHandle scratch_cp,
1.1145 + int old_index, int new_index) {
1.1146 + if (find_new_index(old_index) != 0) {
1.1147 + // old_index is already mapped
1.1148 + return;
1.1149 + }
1.1150 +
1.1151 + if (old_index == new_index) {
1.1152 + // no mapping is needed
1.1153 + return;
1.1154 + }
1.1155 +
1.1156 + _index_map_p->at_put(old_index, new_index);
1.1157 + _index_map_count++;
1.1158 +
1.1159 + RC_TRACE(0x00040000, ("mapped tag %d at index %d to %d",
1.1160 + scratch_cp->tag_at(old_index).value(), old_index, new_index));
1.1161 +} // end map_index()
1.1162 +
1.1163 +
1.1164 +// Map old_index to new_index as needed.
1.1165 +void VM_RedefineClasses::map_operand_index(int old_index, int new_index) {
1.1166 + if (find_new_operand_index(old_index) != -1) {
1.1167 + // old_index is already mapped
1.1168 + return;
1.1169 + }
1.1170 +
1.1171 + if (old_index == new_index) {
1.1172 + // no mapping is needed
1.1173 + return;
1.1174 + }
1.1175 +
1.1176 + _operands_index_map_p->at_put(old_index, new_index);
1.1177 + _operands_index_map_count++;
1.1178 +
1.1179 + RC_TRACE(0x00040000, ("mapped bootstrap specifier at index %d to %d", old_index, new_index));
1.1180 +} // end map_index()
1.1181 +
1.1182 +
1.1183 +// Merge old_cp and scratch_cp and return the results of the merge via
1.1184 +// merge_cp_p. The number of entries in *merge_cp_p is returned via
1.1185 +// merge_cp_length_p. The entries in old_cp occupy the same locations
1.1186 +// in *merge_cp_p. Also creates a map of indices from entries in
1.1187 +// scratch_cp to the corresponding entry in *merge_cp_p. Index map
1.1188 +// entries are only created for entries in scratch_cp that occupy a
1.1189 +// different location in *merged_cp_p.
1.1190 +bool VM_RedefineClasses::merge_constant_pools(constantPoolHandle old_cp,
1.1191 + constantPoolHandle scratch_cp, constantPoolHandle *merge_cp_p,
1.1192 + int *merge_cp_length_p, TRAPS) {
1.1193 +
1.1194 + if (merge_cp_p == NULL) {
1.1195 + assert(false, "caller must provide scratch constantPool");
1.1196 + return false; // robustness
1.1197 + }
1.1198 + if (merge_cp_length_p == NULL) {
1.1199 + assert(false, "caller must provide scratch CP length");
1.1200 + return false; // robustness
1.1201 + }
1.1202 + // Worst case we need old_cp->length() + scratch_cp()->length(),
1.1203 + // but the caller might be smart so make sure we have at least
1.1204 + // the minimum.
1.1205 + if ((*merge_cp_p)->length() < old_cp->length()) {
1.1206 + assert(false, "merge area too small");
1.1207 + return false; // robustness
1.1208 + }
1.1209 +
1.1210 + RC_TRACE_WITH_THREAD(0x00010000, THREAD,
1.1211 + ("old_cp_len=%d, scratch_cp_len=%d", old_cp->length(),
1.1212 + scratch_cp->length()));
1.1213 +
1.1214 + {
1.1215 + // Pass 0:
1.1216 + // The old_cp is copied to *merge_cp_p; this means that any code
1.1217 + // using old_cp does not have to change. This work looks like a
1.1218 + // perfect fit for ConstantPool*::copy_cp_to(), but we need to
1.1219 + // handle one special case:
1.1220 + // - revert JVM_CONSTANT_Class to JVM_CONSTANT_UnresolvedClass
1.1221 + // This will make verification happy.
1.1222 +
1.1223 + int old_i; // index into old_cp
1.1224 +
1.1225 + // index zero (0) is not used in constantPools
1.1226 + for (old_i = 1; old_i < old_cp->length(); old_i++) {
1.1227 + // leave debugging crumb
1.1228 + jbyte old_tag = old_cp->tag_at(old_i).value();
1.1229 + switch (old_tag) {
1.1230 + case JVM_CONSTANT_Class:
1.1231 + case JVM_CONSTANT_UnresolvedClass:
1.1232 + // revert the copy to JVM_CONSTANT_UnresolvedClass
1.1233 + // May be resolving while calling this so do the same for
1.1234 + // JVM_CONSTANT_UnresolvedClass (klass_name_at() deals with transition)
1.1235 + (*merge_cp_p)->unresolved_klass_at_put(old_i,
1.1236 + old_cp->klass_name_at(old_i));
1.1237 + break;
1.1238 +
1.1239 + case JVM_CONSTANT_Double:
1.1240 + case JVM_CONSTANT_Long:
1.1241 + // just copy the entry to *merge_cp_p, but double and long take
1.1242 + // two constant pool entries
1.1243 + ConstantPool::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i, CHECK_0);
1.1244 + old_i++;
1.1245 + break;
1.1246 +
1.1247 + default:
1.1248 + // just copy the entry to *merge_cp_p
1.1249 + ConstantPool::copy_entry_to(old_cp, old_i, *merge_cp_p, old_i, CHECK_0);
1.1250 + break;
1.1251 + }
1.1252 + } // end for each old_cp entry
1.1253 +
1.1254 + ConstantPool::copy_operands(old_cp, *merge_cp_p, CHECK_0);
1.1255 + (*merge_cp_p)->extend_operands(scratch_cp, CHECK_0);
1.1256 +
1.1257 + // We don't need to sanity check that *merge_cp_length_p is within
1.1258 + // *merge_cp_p bounds since we have the minimum on-entry check above.
1.1259 + (*merge_cp_length_p) = old_i;
1.1260 + }
1.1261 +
1.1262 + // merge_cp_len should be the same as old_cp->length() at this point
1.1263 + // so this trace message is really a "warm-and-breathing" message.
1.1264 + RC_TRACE_WITH_THREAD(0x00020000, THREAD,
1.1265 + ("after pass 0: merge_cp_len=%d", *merge_cp_length_p));
1.1266 +
1.1267 + int scratch_i; // index into scratch_cp
1.1268 + {
1.1269 + // Pass 1a:
1.1270 + // Compare scratch_cp entries to the old_cp entries that we have
1.1271 + // already copied to *merge_cp_p. In this pass, we are eliminating
1.1272 + // exact duplicates (matching entry at same index) so we only
1.1273 + // compare entries in the common indice range.
1.1274 + int increment = 1;
1.1275 + int pass1a_length = MIN2(old_cp->length(), scratch_cp->length());
1.1276 + for (scratch_i = 1; scratch_i < pass1a_length; scratch_i += increment) {
1.1277 + switch (scratch_cp->tag_at(scratch_i).value()) {
1.1278 + case JVM_CONSTANT_Double:
1.1279 + case JVM_CONSTANT_Long:
1.1280 + // double and long take two constant pool entries
1.1281 + increment = 2;
1.1282 + break;
1.1283 +
1.1284 + default:
1.1285 + increment = 1;
1.1286 + break;
1.1287 + }
1.1288 +
1.1289 + bool match = scratch_cp->compare_entry_to(scratch_i, *merge_cp_p,
1.1290 + scratch_i, CHECK_0);
1.1291 + if (match) {
1.1292 + // found a match at the same index so nothing more to do
1.1293 + continue;
1.1294 + } else if (is_unresolved_class_mismatch(scratch_cp, scratch_i,
1.1295 + *merge_cp_p, scratch_i)) {
1.1296 + // The mismatch in compare_entry_to() above is because of a
1.1297 + // resolved versus unresolved class entry at the same index
1.1298 + // with the same string value. Since Pass 0 reverted any
1.1299 + // class entries to unresolved class entries in *merge_cp_p,
1.1300 + // we go with the unresolved class entry.
1.1301 + continue;
1.1302 + }
1.1303 +
1.1304 + int found_i = scratch_cp->find_matching_entry(scratch_i, *merge_cp_p,
1.1305 + CHECK_0);
1.1306 + if (found_i != 0) {
1.1307 + guarantee(found_i != scratch_i,
1.1308 + "compare_entry_to() and find_matching_entry() do not agree");
1.1309 +
1.1310 + // Found a matching entry somewhere else in *merge_cp_p so
1.1311 + // just need a mapping entry.
1.1312 + map_index(scratch_cp, scratch_i, found_i);
1.1313 + continue;
1.1314 + }
1.1315 +
1.1316 + // The find_matching_entry() call above could fail to find a match
1.1317 + // due to a resolved versus unresolved class or string entry situation
1.1318 + // like we solved above with the is_unresolved_*_mismatch() calls.
1.1319 + // However, we would have to call is_unresolved_*_mismatch() over
1.1320 + // all of *merge_cp_p (potentially) and that doesn't seem to be
1.1321 + // worth the time.
1.1322 +
1.1323 + // No match found so we have to append this entry and any unique
1.1324 + // referenced entries to *merge_cp_p.
1.1325 + append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p,
1.1326 + CHECK_0);
1.1327 + }
1.1328 + }
1.1329 +
1.1330 + RC_TRACE_WITH_THREAD(0x00020000, THREAD,
1.1331 + ("after pass 1a: merge_cp_len=%d, scratch_i=%d, index_map_len=%d",
1.1332 + *merge_cp_length_p, scratch_i, _index_map_count));
1.1333 +
1.1334 + if (scratch_i < scratch_cp->length()) {
1.1335 + // Pass 1b:
1.1336 + // old_cp is smaller than scratch_cp so there are entries in
1.1337 + // scratch_cp that we have not yet processed. We take care of
1.1338 + // those now.
1.1339 + int increment = 1;
1.1340 + for (; scratch_i < scratch_cp->length(); scratch_i += increment) {
1.1341 + switch (scratch_cp->tag_at(scratch_i).value()) {
1.1342 + case JVM_CONSTANT_Double:
1.1343 + case JVM_CONSTANT_Long:
1.1344 + // double and long take two constant pool entries
1.1345 + increment = 2;
1.1346 + break;
1.1347 +
1.1348 + default:
1.1349 + increment = 1;
1.1350 + break;
1.1351 + }
1.1352 +
1.1353 + int found_i =
1.1354 + scratch_cp->find_matching_entry(scratch_i, *merge_cp_p, CHECK_0);
1.1355 + if (found_i != 0) {
1.1356 + // Found a matching entry somewhere else in *merge_cp_p so
1.1357 + // just need a mapping entry.
1.1358 + map_index(scratch_cp, scratch_i, found_i);
1.1359 + continue;
1.1360 + }
1.1361 +
1.1362 + // No match found so we have to append this entry and any unique
1.1363 + // referenced entries to *merge_cp_p.
1.1364 + append_entry(scratch_cp, scratch_i, merge_cp_p, merge_cp_length_p,
1.1365 + CHECK_0);
1.1366 + }
1.1367 +
1.1368 + RC_TRACE_WITH_THREAD(0x00020000, THREAD,
1.1369 + ("after pass 1b: merge_cp_len=%d, scratch_i=%d, index_map_len=%d",
1.1370 + *merge_cp_length_p, scratch_i, _index_map_count));
1.1371 + }
1.1372 + finalize_operands_merge(*merge_cp_p, THREAD);
1.1373 +
1.1374 + return true;
1.1375 +} // end merge_constant_pools()
1.1376 +
1.1377 +
1.1378 +// Scoped object to clean up the constant pool(s) created for merging
1.1379 +class MergeCPCleaner {
1.1380 + ClassLoaderData* _loader_data;
1.1381 + ConstantPool* _cp;
1.1382 + ConstantPool* _scratch_cp;
1.1383 + public:
1.1384 + MergeCPCleaner(ClassLoaderData* loader_data, ConstantPool* merge_cp) :
1.1385 + _loader_data(loader_data), _cp(merge_cp), _scratch_cp(NULL) {}
1.1386 + ~MergeCPCleaner() {
1.1387 + _loader_data->add_to_deallocate_list(_cp);
1.1388 + if (_scratch_cp != NULL) {
1.1389 + _loader_data->add_to_deallocate_list(_scratch_cp);
1.1390 + }
1.1391 + }
1.1392 + void add_scratch_cp(ConstantPool* scratch_cp) { _scratch_cp = scratch_cp; }
1.1393 +};
1.1394 +
1.1395 +// Merge constant pools between the_class and scratch_class and
1.1396 +// potentially rewrite bytecodes in scratch_class to use the merged
1.1397 +// constant pool.
1.1398 +jvmtiError VM_RedefineClasses::merge_cp_and_rewrite(
1.1399 + instanceKlassHandle the_class, instanceKlassHandle scratch_class,
1.1400 + TRAPS) {
1.1401 + // worst case merged constant pool length is old and new combined
1.1402 + int merge_cp_length = the_class->constants()->length()
1.1403 + + scratch_class->constants()->length();
1.1404 +
1.1405 + // Constant pools are not easily reused so we allocate a new one
1.1406 + // each time.
1.1407 + // merge_cp is created unsafe for concurrent GC processing. It
1.1408 + // should be marked safe before discarding it. Even though
1.1409 + // garbage, if it crosses a card boundary, it may be scanned
1.1410 + // in order to find the start of the first complete object on the card.
1.1411 + ClassLoaderData* loader_data = the_class->class_loader_data();
1.1412 + ConstantPool* merge_cp_oop =
1.1413 + ConstantPool::allocate(loader_data,
1.1414 + merge_cp_length,
1.1415 + CHECK_(JVMTI_ERROR_OUT_OF_MEMORY));
1.1416 + MergeCPCleaner cp_cleaner(loader_data, merge_cp_oop);
1.1417 +
1.1418 + HandleMark hm(THREAD); // make sure handles are cleared before
1.1419 + // MergeCPCleaner clears out merge_cp_oop
1.1420 + constantPoolHandle merge_cp(THREAD, merge_cp_oop);
1.1421 +
1.1422 + // Get constants() from the old class because it could have been rewritten
1.1423 + // while we were at a safepoint allocating a new constant pool.
1.1424 + constantPoolHandle old_cp(THREAD, the_class->constants());
1.1425 + constantPoolHandle scratch_cp(THREAD, scratch_class->constants());
1.1426 +
1.1427 + // If the length changed, the class was redefined out from under us. Return
1.1428 + // an error.
1.1429 + if (merge_cp_length != the_class->constants()->length()
1.1430 + + scratch_class->constants()->length()) {
1.1431 + return JVMTI_ERROR_INTERNAL;
1.1432 + }
1.1433 +
1.1434 + // Update the version number of the constant pool
1.1435 + merge_cp->increment_and_save_version(old_cp->version());
1.1436 +
1.1437 + ResourceMark rm(THREAD);
1.1438 + _index_map_count = 0;
1.1439 + _index_map_p = new intArray(scratch_cp->length(), -1);
1.1440 +
1.1441 + _operands_cur_length = ConstantPool::operand_array_length(old_cp->operands());
1.1442 + _operands_index_map_count = 0;
1.1443 + _operands_index_map_p = new intArray(
1.1444 + ConstantPool::operand_array_length(scratch_cp->operands()), -1);
1.1445 +
1.1446 + // reference to the cp holder is needed for copy_operands()
1.1447 + merge_cp->set_pool_holder(scratch_class());
1.1448 + bool result = merge_constant_pools(old_cp, scratch_cp, &merge_cp,
1.1449 + &merge_cp_length, THREAD);
1.1450 + merge_cp->set_pool_holder(NULL);
1.1451 +
1.1452 + if (!result) {
1.1453 + // The merge can fail due to memory allocation failure or due
1.1454 + // to robustness checks.
1.1455 + return JVMTI_ERROR_INTERNAL;
1.1456 + }
1.1457 +
1.1458 + RC_TRACE_WITH_THREAD(0x00010000, THREAD,
1.1459 + ("merge_cp_len=%d, index_map_len=%d", merge_cp_length, _index_map_count));
1.1460 +
1.1461 + if (_index_map_count == 0) {
1.1462 + // there is nothing to map between the new and merged constant pools
1.1463 +
1.1464 + if (old_cp->length() == scratch_cp->length()) {
1.1465 + // The old and new constant pools are the same length and the
1.1466 + // index map is empty. This means that the three constant pools
1.1467 + // are equivalent (but not the same). Unfortunately, the new
1.1468 + // constant pool has not gone through link resolution nor have
1.1469 + // the new class bytecodes gone through constant pool cache
1.1470 + // rewriting so we can't use the old constant pool with the new
1.1471 + // class.
1.1472 +
1.1473 + // toss the merged constant pool at return
1.1474 + } else if (old_cp->length() < scratch_cp->length()) {
1.1475 + // The old constant pool has fewer entries than the new constant
1.1476 + // pool and the index map is empty. This means the new constant
1.1477 + // pool is a superset of the old constant pool. However, the old
1.1478 + // class bytecodes have already gone through constant pool cache
1.1479 + // rewriting so we can't use the new constant pool with the old
1.1480 + // class.
1.1481 +
1.1482 + // toss the merged constant pool at return
1.1483 + } else {
1.1484 + // The old constant pool has more entries than the new constant
1.1485 + // pool and the index map is empty. This means that both the old
1.1486 + // and merged constant pools are supersets of the new constant
1.1487 + // pool.
1.1488 +
1.1489 + // Replace the new constant pool with a shrunken copy of the
1.1490 + // merged constant pool
1.1491 + set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length,
1.1492 + CHECK_(JVMTI_ERROR_OUT_OF_MEMORY));
1.1493 + // The new constant pool replaces scratch_cp so have cleaner clean it up.
1.1494 + // It can't be cleaned up while there are handles to it.
1.1495 + cp_cleaner.add_scratch_cp(scratch_cp());
1.1496 + }
1.1497 + } else {
1.1498 + if (RC_TRACE_ENABLED(0x00040000)) {
1.1499 + // don't want to loop unless we are tracing
1.1500 + int count = 0;
1.1501 + for (int i = 1; i < _index_map_p->length(); i++) {
1.1502 + int value = _index_map_p->at(i);
1.1503 +
1.1504 + if (value != -1) {
1.1505 + RC_TRACE_WITH_THREAD(0x00040000, THREAD,
1.1506 + ("index_map[%d]: old=%d new=%d", count, i, value));
1.1507 + count++;
1.1508 + }
1.1509 + }
1.1510 + }
1.1511 +
1.1512 + // We have entries mapped between the new and merged constant pools
1.1513 + // so we have to rewrite some constant pool references.
1.1514 + if (!rewrite_cp_refs(scratch_class, THREAD)) {
1.1515 + return JVMTI_ERROR_INTERNAL;
1.1516 + }
1.1517 +
1.1518 + // Replace the new constant pool with a shrunken copy of the
1.1519 + // merged constant pool so now the rewritten bytecodes have
1.1520 + // valid references; the previous new constant pool will get
1.1521 + // GCed.
1.1522 + set_new_constant_pool(loader_data, scratch_class, merge_cp, merge_cp_length,
1.1523 + CHECK_(JVMTI_ERROR_OUT_OF_MEMORY));
1.1524 + // The new constant pool replaces scratch_cp so have cleaner clean it up.
1.1525 + // It can't be cleaned up while there are handles to it.
1.1526 + cp_cleaner.add_scratch_cp(scratch_cp());
1.1527 + }
1.1528 +
1.1529 + return JVMTI_ERROR_NONE;
1.1530 +} // end merge_cp_and_rewrite()
1.1531 +
1.1532 +
1.1533 +// Rewrite constant pool references in klass scratch_class.
1.1534 +bool VM_RedefineClasses::rewrite_cp_refs(instanceKlassHandle scratch_class,
1.1535 + TRAPS) {
1.1536 +
1.1537 + // rewrite constant pool references in the methods:
1.1538 + if (!rewrite_cp_refs_in_methods(scratch_class, THREAD)) {
1.1539 + // propagate failure back to caller
1.1540 + return false;
1.1541 + }
1.1542 +
1.1543 + // rewrite constant pool references in the class_annotations:
1.1544 + if (!rewrite_cp_refs_in_class_annotations(scratch_class, THREAD)) {
1.1545 + // propagate failure back to caller
1.1546 + return false;
1.1547 + }
1.1548 +
1.1549 + // rewrite constant pool references in the fields_annotations:
1.1550 + if (!rewrite_cp_refs_in_fields_annotations(scratch_class, THREAD)) {
1.1551 + // propagate failure back to caller
1.1552 + return false;
1.1553 + }
1.1554 +
1.1555 + // rewrite constant pool references in the methods_annotations:
1.1556 + if (!rewrite_cp_refs_in_methods_annotations(scratch_class, THREAD)) {
1.1557 + // propagate failure back to caller
1.1558 + return false;
1.1559 + }
1.1560 +
1.1561 + // rewrite constant pool references in the methods_parameter_annotations:
1.1562 + if (!rewrite_cp_refs_in_methods_parameter_annotations(scratch_class,
1.1563 + THREAD)) {
1.1564 + // propagate failure back to caller
1.1565 + return false;
1.1566 + }
1.1567 +
1.1568 + // rewrite constant pool references in the methods_default_annotations:
1.1569 + if (!rewrite_cp_refs_in_methods_default_annotations(scratch_class,
1.1570 + THREAD)) {
1.1571 + // propagate failure back to caller
1.1572 + return false;
1.1573 + }
1.1574 +
1.1575 + // rewrite source file name index:
1.1576 + u2 source_file_name_idx = scratch_class->source_file_name_index();
1.1577 + if (source_file_name_idx != 0) {
1.1578 + u2 new_source_file_name_idx = find_new_index(source_file_name_idx);
1.1579 + if (new_source_file_name_idx != 0) {
1.1580 + scratch_class->set_source_file_name_index(new_source_file_name_idx);
1.1581 + }
1.1582 + }
1.1583 +
1.1584 + // rewrite class generic signature index:
1.1585 + u2 generic_signature_index = scratch_class->generic_signature_index();
1.1586 + if (generic_signature_index != 0) {
1.1587 + u2 new_generic_signature_index = find_new_index(generic_signature_index);
1.1588 + if (new_generic_signature_index != 0) {
1.1589 + scratch_class->set_generic_signature_index(new_generic_signature_index);
1.1590 + }
1.1591 + }
1.1592 +
1.1593 + return true;
1.1594 +} // end rewrite_cp_refs()
1.1595 +
1.1596 +// Rewrite constant pool references in the methods.
1.1597 +bool VM_RedefineClasses::rewrite_cp_refs_in_methods(
1.1598 + instanceKlassHandle scratch_class, TRAPS) {
1.1599 +
1.1600 + Array<Method*>* methods = scratch_class->methods();
1.1601 +
1.1602 + if (methods == NULL || methods->length() == 0) {
1.1603 + // no methods so nothing to do
1.1604 + return true;
1.1605 + }
1.1606 +
1.1607 + // rewrite constant pool references in the methods:
1.1608 + for (int i = methods->length() - 1; i >= 0; i--) {
1.1609 + methodHandle method(THREAD, methods->at(i));
1.1610 + methodHandle new_method;
1.1611 + rewrite_cp_refs_in_method(method, &new_method, THREAD);
1.1612 + if (!new_method.is_null()) {
1.1613 + // the method has been replaced so save the new method version
1.1614 + // even in the case of an exception. original method is on the
1.1615 + // deallocation list.
1.1616 + methods->at_put(i, new_method());
1.1617 + }
1.1618 + if (HAS_PENDING_EXCEPTION) {
1.1619 + Symbol* ex_name = PENDING_EXCEPTION->klass()->name();
1.1620 + // RC_TRACE_WITH_THREAD macro has an embedded ResourceMark
1.1621 + RC_TRACE_WITH_THREAD(0x00000002, THREAD,
1.1622 + ("rewrite_cp_refs_in_method exception: '%s'", ex_name->as_C_string()));
1.1623 + // Need to clear pending exception here as the super caller sets
1.1624 + // the JVMTI_ERROR_INTERNAL if the returned value is false.
1.1625 + CLEAR_PENDING_EXCEPTION;
1.1626 + return false;
1.1627 + }
1.1628 + }
1.1629 +
1.1630 + return true;
1.1631 +}
1.1632 +
1.1633 +
1.1634 +// Rewrite constant pool references in the specific method. This code
1.1635 +// was adapted from Rewriter::rewrite_method().
1.1636 +void VM_RedefineClasses::rewrite_cp_refs_in_method(methodHandle method,
1.1637 + methodHandle *new_method_p, TRAPS) {
1.1638 +
1.1639 + *new_method_p = methodHandle(); // default is no new method
1.1640 +
1.1641 + // We cache a pointer to the bytecodes here in code_base. If GC
1.1642 + // moves the Method*, then the bytecodes will also move which
1.1643 + // will likely cause a crash. We create a No_Safepoint_Verifier
1.1644 + // object to detect whether we pass a possible safepoint in this
1.1645 + // code block.
1.1646 + No_Safepoint_Verifier nsv;
1.1647 +
1.1648 + // Bytecodes and their length
1.1649 + address code_base = method->code_base();
1.1650 + int code_length = method->code_size();
1.1651 +
1.1652 + int bc_length;
1.1653 + for (int bci = 0; bci < code_length; bci += bc_length) {
1.1654 + address bcp = code_base + bci;
1.1655 + Bytecodes::Code c = (Bytecodes::Code)(*bcp);
1.1656 +
1.1657 + bc_length = Bytecodes::length_for(c);
1.1658 + if (bc_length == 0) {
1.1659 + // More complicated bytecodes report a length of zero so
1.1660 + // we have to try again a slightly different way.
1.1661 + bc_length = Bytecodes::length_at(method(), bcp);
1.1662 + }
1.1663 +
1.1664 + assert(bc_length != 0, "impossible bytecode length");
1.1665 +
1.1666 + switch (c) {
1.1667 + case Bytecodes::_ldc:
1.1668 + {
1.1669 + int cp_index = *(bcp + 1);
1.1670 + int new_index = find_new_index(cp_index);
1.1671 +
1.1672 + if (StressLdcRewrite && new_index == 0) {
1.1673 + // If we are stressing ldc -> ldc_w rewriting, then we
1.1674 + // always need a new_index value.
1.1675 + new_index = cp_index;
1.1676 + }
1.1677 + if (new_index != 0) {
1.1678 + // the original index is mapped so we have more work to do
1.1679 + if (!StressLdcRewrite && new_index <= max_jubyte) {
1.1680 + // The new value can still use ldc instead of ldc_w
1.1681 + // unless we are trying to stress ldc -> ldc_w rewriting
1.1682 + RC_TRACE_WITH_THREAD(0x00080000, THREAD,
1.1683 + ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c),
1.1684 + bcp, cp_index, new_index));
1.1685 + *(bcp + 1) = new_index;
1.1686 + } else {
1.1687 + RC_TRACE_WITH_THREAD(0x00080000, THREAD,
1.1688 + ("%s->ldc_w@" INTPTR_FORMAT " old=%d, new=%d",
1.1689 + Bytecodes::name(c), bcp, cp_index, new_index));
1.1690 + // the new value needs ldc_w instead of ldc
1.1691 + u_char inst_buffer[4]; // max instruction size is 4 bytes
1.1692 + bcp = (address)inst_buffer;
1.1693 + // construct new instruction sequence
1.1694 + *bcp = Bytecodes::_ldc_w;
1.1695 + bcp++;
1.1696 + // Rewriter::rewrite_method() does not rewrite ldc -> ldc_w.
1.1697 + // See comment below for difference between put_Java_u2()
1.1698 + // and put_native_u2().
1.1699 + Bytes::put_Java_u2(bcp, new_index);
1.1700 +
1.1701 + Relocator rc(method, NULL /* no RelocatorListener needed */);
1.1702 + methodHandle m;
1.1703 + {
1.1704 + Pause_No_Safepoint_Verifier pnsv(&nsv);
1.1705 +
1.1706 + // ldc is 2 bytes and ldc_w is 3 bytes
1.1707 + m = rc.insert_space_at(bci, 3, inst_buffer, CHECK);
1.1708 + }
1.1709 +
1.1710 + // return the new method so that the caller can update
1.1711 + // the containing class
1.1712 + *new_method_p = method = m;
1.1713 + // switch our bytecode processing loop from the old method
1.1714 + // to the new method
1.1715 + code_base = method->code_base();
1.1716 + code_length = method->code_size();
1.1717 + bcp = code_base + bci;
1.1718 + c = (Bytecodes::Code)(*bcp);
1.1719 + bc_length = Bytecodes::length_for(c);
1.1720 + assert(bc_length != 0, "sanity check");
1.1721 + } // end we need ldc_w instead of ldc
1.1722 + } // end if there is a mapped index
1.1723 + } break;
1.1724 +
1.1725 + // these bytecodes have a two-byte constant pool index
1.1726 + case Bytecodes::_anewarray : // fall through
1.1727 + case Bytecodes::_checkcast : // fall through
1.1728 + case Bytecodes::_getfield : // fall through
1.1729 + case Bytecodes::_getstatic : // fall through
1.1730 + case Bytecodes::_instanceof : // fall through
1.1731 + case Bytecodes::_invokedynamic : // fall through
1.1732 + case Bytecodes::_invokeinterface: // fall through
1.1733 + case Bytecodes::_invokespecial : // fall through
1.1734 + case Bytecodes::_invokestatic : // fall through
1.1735 + case Bytecodes::_invokevirtual : // fall through
1.1736 + case Bytecodes::_ldc_w : // fall through
1.1737 + case Bytecodes::_ldc2_w : // fall through
1.1738 + case Bytecodes::_multianewarray : // fall through
1.1739 + case Bytecodes::_new : // fall through
1.1740 + case Bytecodes::_putfield : // fall through
1.1741 + case Bytecodes::_putstatic :
1.1742 + {
1.1743 + address p = bcp + 1;
1.1744 + int cp_index = Bytes::get_Java_u2(p);
1.1745 + int new_index = find_new_index(cp_index);
1.1746 + if (new_index != 0) {
1.1747 + // the original index is mapped so update w/ new value
1.1748 + RC_TRACE_WITH_THREAD(0x00080000, THREAD,
1.1749 + ("%s@" INTPTR_FORMAT " old=%d, new=%d", Bytecodes::name(c),
1.1750 + bcp, cp_index, new_index));
1.1751 + // Rewriter::rewrite_method() uses put_native_u2() in this
1.1752 + // situation because it is reusing the constant pool index
1.1753 + // location for a native index into the ConstantPoolCache.
1.1754 + // Since we are updating the constant pool index prior to
1.1755 + // verification and ConstantPoolCache initialization, we
1.1756 + // need to keep the new index in Java byte order.
1.1757 + Bytes::put_Java_u2(p, new_index);
1.1758 + }
1.1759 + } break;
1.1760 + }
1.1761 + } // end for each bytecode
1.1762 +
1.1763 + // We also need to rewrite the parameter name indexes, if there is
1.1764 + // method parameter data present
1.1765 + if(method->has_method_parameters()) {
1.1766 + const int len = method->method_parameters_length();
1.1767 + MethodParametersElement* elem = method->method_parameters_start();
1.1768 +
1.1769 + for (int i = 0; i < len; i++) {
1.1770 + const u2 cp_index = elem[i].name_cp_index;
1.1771 + const u2 new_cp_index = find_new_index(cp_index);
1.1772 + if (new_cp_index != 0) {
1.1773 + elem[i].name_cp_index = new_cp_index;
1.1774 + }
1.1775 + }
1.1776 + }
1.1777 +} // end rewrite_cp_refs_in_method()
1.1778 +
1.1779 +
1.1780 +// Rewrite constant pool references in the class_annotations field.
1.1781 +bool VM_RedefineClasses::rewrite_cp_refs_in_class_annotations(
1.1782 + instanceKlassHandle scratch_class, TRAPS) {
1.1783 +
1.1784 + AnnotationArray* class_annotations = scratch_class->class_annotations();
1.1785 + if (class_annotations == NULL || class_annotations->length() == 0) {
1.1786 + // no class_annotations so nothing to do
1.1787 + return true;
1.1788 + }
1.1789 +
1.1790 + RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1.1791 + ("class_annotations length=%d", class_annotations->length()));
1.1792 +
1.1793 + int byte_i = 0; // byte index into class_annotations
1.1794 + return rewrite_cp_refs_in_annotations_typeArray(class_annotations, byte_i,
1.1795 + THREAD);
1.1796 +}
1.1797 +
1.1798 +
1.1799 +// Rewrite constant pool references in an annotations typeArray. This
1.1800 +// "structure" is adapted from the RuntimeVisibleAnnotations_attribute
1.1801 +// that is described in section 4.8.15 of the 2nd-edition of the VM spec:
1.1802 +//
1.1803 +// annotations_typeArray {
1.1804 +// u2 num_annotations;
1.1805 +// annotation annotations[num_annotations];
1.1806 +// }
1.1807 +//
1.1808 +bool VM_RedefineClasses::rewrite_cp_refs_in_annotations_typeArray(
1.1809 + AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) {
1.1810 +
1.1811 + if ((byte_i_ref + 2) > annotations_typeArray->length()) {
1.1812 + // not enough room for num_annotations field
1.1813 + RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1.1814 + ("length() is too small for num_annotations field"));
1.1815 + return false;
1.1816 + }
1.1817 +
1.1818 + u2 num_annotations = Bytes::get_Java_u2((address)
1.1819 + annotations_typeArray->adr_at(byte_i_ref));
1.1820 + byte_i_ref += 2;
1.1821 +
1.1822 + RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1.1823 + ("num_annotations=%d", num_annotations));
1.1824 +
1.1825 + int calc_num_annotations = 0;
1.1826 + for (; calc_num_annotations < num_annotations; calc_num_annotations++) {
1.1827 + if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray,
1.1828 + byte_i_ref, THREAD)) {
1.1829 + RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1.1830 + ("bad annotation_struct at %d", calc_num_annotations));
1.1831 + // propagate failure back to caller
1.1832 + return false;
1.1833 + }
1.1834 + }
1.1835 + assert(num_annotations == calc_num_annotations, "sanity check");
1.1836 +
1.1837 + return true;
1.1838 +} // end rewrite_cp_refs_in_annotations_typeArray()
1.1839 +
1.1840 +
1.1841 +// Rewrite constant pool references in the annotation struct portion of
1.1842 +// an annotations_typeArray. This "structure" is from section 4.8.15 of
1.1843 +// the 2nd-edition of the VM spec:
1.1844 +//
1.1845 +// struct annotation {
1.1846 +// u2 type_index;
1.1847 +// u2 num_element_value_pairs;
1.1848 +// {
1.1849 +// u2 element_name_index;
1.1850 +// element_value value;
1.1851 +// } element_value_pairs[num_element_value_pairs];
1.1852 +// }
1.1853 +//
1.1854 +bool VM_RedefineClasses::rewrite_cp_refs_in_annotation_struct(
1.1855 + AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) {
1.1856 + if ((byte_i_ref + 2 + 2) > annotations_typeArray->length()) {
1.1857 + // not enough room for smallest annotation_struct
1.1858 + RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1.1859 + ("length() is too small for annotation_struct"));
1.1860 + return false;
1.1861 + }
1.1862 +
1.1863 + u2 type_index = rewrite_cp_ref_in_annotation_data(annotations_typeArray,
1.1864 + byte_i_ref, "mapped old type_index=%d", THREAD);
1.1865 +
1.1866 + u2 num_element_value_pairs = Bytes::get_Java_u2((address)
1.1867 + annotations_typeArray->adr_at(byte_i_ref));
1.1868 + byte_i_ref += 2;
1.1869 +
1.1870 + RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1.1871 + ("type_index=%d num_element_value_pairs=%d", type_index,
1.1872 + num_element_value_pairs));
1.1873 +
1.1874 + int calc_num_element_value_pairs = 0;
1.1875 + for (; calc_num_element_value_pairs < num_element_value_pairs;
1.1876 + calc_num_element_value_pairs++) {
1.1877 + if ((byte_i_ref + 2) > annotations_typeArray->length()) {
1.1878 + // not enough room for another element_name_index, let alone
1.1879 + // the rest of another component
1.1880 + RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1.1881 + ("length() is too small for element_name_index"));
1.1882 + return false;
1.1883 + }
1.1884 +
1.1885 + u2 element_name_index = rewrite_cp_ref_in_annotation_data(
1.1886 + annotations_typeArray, byte_i_ref,
1.1887 + "mapped old element_name_index=%d", THREAD);
1.1888 +
1.1889 + RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1.1890 + ("element_name_index=%d", element_name_index));
1.1891 +
1.1892 + if (!rewrite_cp_refs_in_element_value(annotations_typeArray,
1.1893 + byte_i_ref, THREAD)) {
1.1894 + RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1.1895 + ("bad element_value at %d", calc_num_element_value_pairs));
1.1896 + // propagate failure back to caller
1.1897 + return false;
1.1898 + }
1.1899 + } // end for each component
1.1900 + assert(num_element_value_pairs == calc_num_element_value_pairs,
1.1901 + "sanity check");
1.1902 +
1.1903 + return true;
1.1904 +} // end rewrite_cp_refs_in_annotation_struct()
1.1905 +
1.1906 +
1.1907 +// Rewrite a constant pool reference at the current position in
1.1908 +// annotations_typeArray if needed. Returns the original constant
1.1909 +// pool reference if a rewrite was not needed or the new constant
1.1910 +// pool reference if a rewrite was needed.
1.1911 +PRAGMA_DIAG_PUSH
1.1912 +PRAGMA_FORMAT_NONLITERAL_IGNORED
1.1913 +u2 VM_RedefineClasses::rewrite_cp_ref_in_annotation_data(
1.1914 + AnnotationArray* annotations_typeArray, int &byte_i_ref,
1.1915 + const char * trace_mesg, TRAPS) {
1.1916 +
1.1917 + address cp_index_addr = (address)
1.1918 + annotations_typeArray->adr_at(byte_i_ref);
1.1919 + u2 old_cp_index = Bytes::get_Java_u2(cp_index_addr);
1.1920 + u2 new_cp_index = find_new_index(old_cp_index);
1.1921 + if (new_cp_index != 0) {
1.1922 + RC_TRACE_WITH_THREAD(0x02000000, THREAD, (trace_mesg, old_cp_index));
1.1923 + Bytes::put_Java_u2(cp_index_addr, new_cp_index);
1.1924 + old_cp_index = new_cp_index;
1.1925 + }
1.1926 + byte_i_ref += 2;
1.1927 + return old_cp_index;
1.1928 +}
1.1929 +PRAGMA_DIAG_POP
1.1930 +
1.1931 +
1.1932 +// Rewrite constant pool references in the element_value portion of an
1.1933 +// annotations_typeArray. This "structure" is from section 4.8.15.1 of
1.1934 +// the 2nd-edition of the VM spec:
1.1935 +//
1.1936 +// struct element_value {
1.1937 +// u1 tag;
1.1938 +// union {
1.1939 +// u2 const_value_index;
1.1940 +// {
1.1941 +// u2 type_name_index;
1.1942 +// u2 const_name_index;
1.1943 +// } enum_const_value;
1.1944 +// u2 class_info_index;
1.1945 +// annotation annotation_value;
1.1946 +// struct {
1.1947 +// u2 num_values;
1.1948 +// element_value values[num_values];
1.1949 +// } array_value;
1.1950 +// } value;
1.1951 +// }
1.1952 +//
1.1953 +bool VM_RedefineClasses::rewrite_cp_refs_in_element_value(
1.1954 + AnnotationArray* annotations_typeArray, int &byte_i_ref, TRAPS) {
1.1955 +
1.1956 + if ((byte_i_ref + 1) > annotations_typeArray->length()) {
1.1957 + // not enough room for a tag let alone the rest of an element_value
1.1958 + RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1.1959 + ("length() is too small for a tag"));
1.1960 + return false;
1.1961 + }
1.1962 +
1.1963 + u1 tag = annotations_typeArray->at(byte_i_ref);
1.1964 + byte_i_ref++;
1.1965 + RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("tag='%c'", tag));
1.1966 +
1.1967 + switch (tag) {
1.1968 + // These BaseType tag values are from Table 4.2 in VM spec:
1.1969 + case 'B': // byte
1.1970 + case 'C': // char
1.1971 + case 'D': // double
1.1972 + case 'F': // float
1.1973 + case 'I': // int
1.1974 + case 'J': // long
1.1975 + case 'S': // short
1.1976 + case 'Z': // boolean
1.1977 +
1.1978 + // The remaining tag values are from Table 4.8 in the 2nd-edition of
1.1979 + // the VM spec:
1.1980 + case 's':
1.1981 + {
1.1982 + // For the above tag values (including the BaseType values),
1.1983 + // value.const_value_index is right union field.
1.1984 +
1.1985 + if ((byte_i_ref + 2) > annotations_typeArray->length()) {
1.1986 + // not enough room for a const_value_index
1.1987 + RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1.1988 + ("length() is too small for a const_value_index"));
1.1989 + return false;
1.1990 + }
1.1991 +
1.1992 + u2 const_value_index = rewrite_cp_ref_in_annotation_data(
1.1993 + annotations_typeArray, byte_i_ref,
1.1994 + "mapped old const_value_index=%d", THREAD);
1.1995 +
1.1996 + RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1.1997 + ("const_value_index=%d", const_value_index));
1.1998 + } break;
1.1999 +
1.2000 + case 'e':
1.2001 + {
1.2002 + // for the above tag value, value.enum_const_value is right union field
1.2003 +
1.2004 + if ((byte_i_ref + 4) > annotations_typeArray->length()) {
1.2005 + // not enough room for a enum_const_value
1.2006 + RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1.2007 + ("length() is too small for a enum_const_value"));
1.2008 + return false;
1.2009 + }
1.2010 +
1.2011 + u2 type_name_index = rewrite_cp_ref_in_annotation_data(
1.2012 + annotations_typeArray, byte_i_ref,
1.2013 + "mapped old type_name_index=%d", THREAD);
1.2014 +
1.2015 + u2 const_name_index = rewrite_cp_ref_in_annotation_data(
1.2016 + annotations_typeArray, byte_i_ref,
1.2017 + "mapped old const_name_index=%d", THREAD);
1.2018 +
1.2019 + RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1.2020 + ("type_name_index=%d const_name_index=%d", type_name_index,
1.2021 + const_name_index));
1.2022 + } break;
1.2023 +
1.2024 + case 'c':
1.2025 + {
1.2026 + // for the above tag value, value.class_info_index is right union field
1.2027 +
1.2028 + if ((byte_i_ref + 2) > annotations_typeArray->length()) {
1.2029 + // not enough room for a class_info_index
1.2030 + RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1.2031 + ("length() is too small for a class_info_index"));
1.2032 + return false;
1.2033 + }
1.2034 +
1.2035 + u2 class_info_index = rewrite_cp_ref_in_annotation_data(
1.2036 + annotations_typeArray, byte_i_ref,
1.2037 + "mapped old class_info_index=%d", THREAD);
1.2038 +
1.2039 + RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1.2040 + ("class_info_index=%d", class_info_index));
1.2041 + } break;
1.2042 +
1.2043 + case '@':
1.2044 + // For the above tag value, value.attr_value is the right union
1.2045 + // field. This is a nested annotation.
1.2046 + if (!rewrite_cp_refs_in_annotation_struct(annotations_typeArray,
1.2047 + byte_i_ref, THREAD)) {
1.2048 + // propagate failure back to caller
1.2049 + return false;
1.2050 + }
1.2051 + break;
1.2052 +
1.2053 + case '[':
1.2054 + {
1.2055 + if ((byte_i_ref + 2) > annotations_typeArray->length()) {
1.2056 + // not enough room for a num_values field
1.2057 + RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1.2058 + ("length() is too small for a num_values field"));
1.2059 + return false;
1.2060 + }
1.2061 +
1.2062 + // For the above tag value, value.array_value is the right union
1.2063 + // field. This is an array of nested element_value.
1.2064 + u2 num_values = Bytes::get_Java_u2((address)
1.2065 + annotations_typeArray->adr_at(byte_i_ref));
1.2066 + byte_i_ref += 2;
1.2067 + RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("num_values=%d", num_values));
1.2068 +
1.2069 + int calc_num_values = 0;
1.2070 + for (; calc_num_values < num_values; calc_num_values++) {
1.2071 + if (!rewrite_cp_refs_in_element_value(
1.2072 + annotations_typeArray, byte_i_ref, THREAD)) {
1.2073 + RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1.2074 + ("bad nested element_value at %d", calc_num_values));
1.2075 + // propagate failure back to caller
1.2076 + return false;
1.2077 + }
1.2078 + }
1.2079 + assert(num_values == calc_num_values, "sanity check");
1.2080 + } break;
1.2081 +
1.2082 + default:
1.2083 + RC_TRACE_WITH_THREAD(0x02000000, THREAD, ("bad tag=0x%x", tag));
1.2084 + return false;
1.2085 + } // end decode tag field
1.2086 +
1.2087 + return true;
1.2088 +} // end rewrite_cp_refs_in_element_value()
1.2089 +
1.2090 +
1.2091 +// Rewrite constant pool references in a fields_annotations field.
1.2092 +bool VM_RedefineClasses::rewrite_cp_refs_in_fields_annotations(
1.2093 + instanceKlassHandle scratch_class, TRAPS) {
1.2094 +
1.2095 + Array<AnnotationArray*>* fields_annotations = scratch_class->fields_annotations();
1.2096 +
1.2097 + if (fields_annotations == NULL || fields_annotations->length() == 0) {
1.2098 + // no fields_annotations so nothing to do
1.2099 + return true;
1.2100 + }
1.2101 +
1.2102 + RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1.2103 + ("fields_annotations length=%d", fields_annotations->length()));
1.2104 +
1.2105 + for (int i = 0; i < fields_annotations->length(); i++) {
1.2106 + AnnotationArray* field_annotations = fields_annotations->at(i);
1.2107 + if (field_annotations == NULL || field_annotations->length() == 0) {
1.2108 + // this field does not have any annotations so skip it
1.2109 + continue;
1.2110 + }
1.2111 +
1.2112 + int byte_i = 0; // byte index into field_annotations
1.2113 + if (!rewrite_cp_refs_in_annotations_typeArray(field_annotations, byte_i,
1.2114 + THREAD)) {
1.2115 + RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1.2116 + ("bad field_annotations at %d", i));
1.2117 + // propagate failure back to caller
1.2118 + return false;
1.2119 + }
1.2120 + }
1.2121 +
1.2122 + return true;
1.2123 +} // end rewrite_cp_refs_in_fields_annotations()
1.2124 +
1.2125 +
1.2126 +// Rewrite constant pool references in a methods_annotations field.
1.2127 +bool VM_RedefineClasses::rewrite_cp_refs_in_methods_annotations(
1.2128 + instanceKlassHandle scratch_class, TRAPS) {
1.2129 +
1.2130 + for (int i = 0; i < scratch_class->methods()->length(); i++) {
1.2131 + Method* m = scratch_class->methods()->at(i);
1.2132 + AnnotationArray* method_annotations = m->constMethod()->method_annotations();
1.2133 +
1.2134 + if (method_annotations == NULL || method_annotations->length() == 0) {
1.2135 + // this method does not have any annotations so skip it
1.2136 + continue;
1.2137 + }
1.2138 +
1.2139 + int byte_i = 0; // byte index into method_annotations
1.2140 + if (!rewrite_cp_refs_in_annotations_typeArray(method_annotations, byte_i,
1.2141 + THREAD)) {
1.2142 + RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1.2143 + ("bad method_annotations at %d", i));
1.2144 + // propagate failure back to caller
1.2145 + return false;
1.2146 + }
1.2147 + }
1.2148 +
1.2149 + return true;
1.2150 +} // end rewrite_cp_refs_in_methods_annotations()
1.2151 +
1.2152 +
1.2153 +// Rewrite constant pool references in a methods_parameter_annotations
1.2154 +// field. This "structure" is adapted from the
1.2155 +// RuntimeVisibleParameterAnnotations_attribute described in section
1.2156 +// 4.8.17 of the 2nd-edition of the VM spec:
1.2157 +//
1.2158 +// methods_parameter_annotations_typeArray {
1.2159 +// u1 num_parameters;
1.2160 +// {
1.2161 +// u2 num_annotations;
1.2162 +// annotation annotations[num_annotations];
1.2163 +// } parameter_annotations[num_parameters];
1.2164 +// }
1.2165 +//
1.2166 +bool VM_RedefineClasses::rewrite_cp_refs_in_methods_parameter_annotations(
1.2167 + instanceKlassHandle scratch_class, TRAPS) {
1.2168 +
1.2169 + for (int i = 0; i < scratch_class->methods()->length(); i++) {
1.2170 + Method* m = scratch_class->methods()->at(i);
1.2171 + AnnotationArray* method_parameter_annotations = m->constMethod()->parameter_annotations();
1.2172 + if (method_parameter_annotations == NULL
1.2173 + || method_parameter_annotations->length() == 0) {
1.2174 + // this method does not have any parameter annotations so skip it
1.2175 + continue;
1.2176 + }
1.2177 +
1.2178 + if (method_parameter_annotations->length() < 1) {
1.2179 + // not enough room for a num_parameters field
1.2180 + RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1.2181 + ("length() is too small for a num_parameters field at %d", i));
1.2182 + return false;
1.2183 + }
1.2184 +
1.2185 + int byte_i = 0; // byte index into method_parameter_annotations
1.2186 +
1.2187 + u1 num_parameters = method_parameter_annotations->at(byte_i);
1.2188 + byte_i++;
1.2189 +
1.2190 + RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1.2191 + ("num_parameters=%d", num_parameters));
1.2192 +
1.2193 + int calc_num_parameters = 0;
1.2194 + for (; calc_num_parameters < num_parameters; calc_num_parameters++) {
1.2195 + if (!rewrite_cp_refs_in_annotations_typeArray(
1.2196 + method_parameter_annotations, byte_i, THREAD)) {
1.2197 + RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1.2198 + ("bad method_parameter_annotations at %d", calc_num_parameters));
1.2199 + // propagate failure back to caller
1.2200 + return false;
1.2201 + }
1.2202 + }
1.2203 + assert(num_parameters == calc_num_parameters, "sanity check");
1.2204 + }
1.2205 +
1.2206 + return true;
1.2207 +} // end rewrite_cp_refs_in_methods_parameter_annotations()
1.2208 +
1.2209 +
1.2210 +// Rewrite constant pool references in a methods_default_annotations
1.2211 +// field. This "structure" is adapted from the AnnotationDefault_attribute
1.2212 +// that is described in section 4.8.19 of the 2nd-edition of the VM spec:
1.2213 +//
1.2214 +// methods_default_annotations_typeArray {
1.2215 +// element_value default_value;
1.2216 +// }
1.2217 +//
1.2218 +bool VM_RedefineClasses::rewrite_cp_refs_in_methods_default_annotations(
1.2219 + instanceKlassHandle scratch_class, TRAPS) {
1.2220 +
1.2221 + for (int i = 0; i < scratch_class->methods()->length(); i++) {
1.2222 + Method* m = scratch_class->methods()->at(i);
1.2223 + AnnotationArray* method_default_annotations = m->constMethod()->default_annotations();
1.2224 + if (method_default_annotations == NULL
1.2225 + || method_default_annotations->length() == 0) {
1.2226 + // this method does not have any default annotations so skip it
1.2227 + continue;
1.2228 + }
1.2229 +
1.2230 + int byte_i = 0; // byte index into method_default_annotations
1.2231 +
1.2232 + if (!rewrite_cp_refs_in_element_value(
1.2233 + method_default_annotations, byte_i, THREAD)) {
1.2234 + RC_TRACE_WITH_THREAD(0x02000000, THREAD,
1.2235 + ("bad default element_value at %d", i));
1.2236 + // propagate failure back to caller
1.2237 + return false;
1.2238 + }
1.2239 + }
1.2240 +
1.2241 + return true;
1.2242 +} // end rewrite_cp_refs_in_methods_default_annotations()
1.2243 +
1.2244 +
1.2245 +// Rewrite constant pool references in the method's stackmap table.
1.2246 +// These "structures" are adapted from the StackMapTable_attribute that
1.2247 +// is described in section 4.8.4 of the 6.0 version of the VM spec
1.2248 +// (dated 2005.10.26):
1.2249 +// file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf
1.2250 +//
1.2251 +// stack_map {
1.2252 +// u2 number_of_entries;
1.2253 +// stack_map_frame entries[number_of_entries];
1.2254 +// }
1.2255 +//
1.2256 +void VM_RedefineClasses::rewrite_cp_refs_in_stack_map_table(
1.2257 + methodHandle method, TRAPS) {
1.2258 +
1.2259 + if (!method->has_stackmap_table()) {
1.2260 + return;
1.2261 + }
1.2262 +
1.2263 + AnnotationArray* stackmap_data = method->stackmap_data();
1.2264 + address stackmap_p = (address)stackmap_data->adr_at(0);
1.2265 + address stackmap_end = stackmap_p + stackmap_data->length();
1.2266 +
1.2267 + assert(stackmap_p + 2 <= stackmap_end, "no room for number_of_entries");
1.2268 + u2 number_of_entries = Bytes::get_Java_u2(stackmap_p);
1.2269 + stackmap_p += 2;
1.2270 +
1.2271 + RC_TRACE_WITH_THREAD(0x04000000, THREAD,
1.2272 + ("number_of_entries=%u", number_of_entries));
1.2273 +
1.2274 + // walk through each stack_map_frame
1.2275 + u2 calc_number_of_entries = 0;
1.2276 + for (; calc_number_of_entries < number_of_entries; calc_number_of_entries++) {
1.2277 + // The stack_map_frame structure is a u1 frame_type followed by
1.2278 + // 0 or more bytes of data:
1.2279 + //
1.2280 + // union stack_map_frame {
1.2281 + // same_frame;
1.2282 + // same_locals_1_stack_item_frame;
1.2283 + // same_locals_1_stack_item_frame_extended;
1.2284 + // chop_frame;
1.2285 + // same_frame_extended;
1.2286 + // append_frame;
1.2287 + // full_frame;
1.2288 + // }
1.2289 +
1.2290 + assert(stackmap_p + 1 <= stackmap_end, "no room for frame_type");
1.2291 + // The Linux compiler does not like frame_type to be u1 or u2. It
1.2292 + // issues the following warning for the first if-statement below:
1.2293 + //
1.2294 + // "warning: comparison is always true due to limited range of data type"
1.2295 + //
1.2296 + u4 frame_type = *stackmap_p;
1.2297 + stackmap_p++;
1.2298 +
1.2299 + // same_frame {
1.2300 + // u1 frame_type = SAME; /* 0-63 */
1.2301 + // }
1.2302 + if (frame_type >= 0 && frame_type <= 63) {
1.2303 + // nothing more to do for same_frame
1.2304 + }
1.2305 +
1.2306 + // same_locals_1_stack_item_frame {
1.2307 + // u1 frame_type = SAME_LOCALS_1_STACK_ITEM; /* 64-127 */
1.2308 + // verification_type_info stack[1];
1.2309 + // }
1.2310 + else if (frame_type >= 64 && frame_type <= 127) {
1.2311 + rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
1.2312 + calc_number_of_entries, frame_type, THREAD);
1.2313 + }
1.2314 +
1.2315 + // reserved for future use
1.2316 + else if (frame_type >= 128 && frame_type <= 246) {
1.2317 + // nothing more to do for reserved frame_types
1.2318 + }
1.2319 +
1.2320 + // same_locals_1_stack_item_frame_extended {
1.2321 + // u1 frame_type = SAME_LOCALS_1_STACK_ITEM_EXTENDED; /* 247 */
1.2322 + // u2 offset_delta;
1.2323 + // verification_type_info stack[1];
1.2324 + // }
1.2325 + else if (frame_type == 247) {
1.2326 + stackmap_p += 2;
1.2327 + rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
1.2328 + calc_number_of_entries, frame_type, THREAD);
1.2329 + }
1.2330 +
1.2331 + // chop_frame {
1.2332 + // u1 frame_type = CHOP; /* 248-250 */
1.2333 + // u2 offset_delta;
1.2334 + // }
1.2335 + else if (frame_type >= 248 && frame_type <= 250) {
1.2336 + stackmap_p += 2;
1.2337 + }
1.2338 +
1.2339 + // same_frame_extended {
1.2340 + // u1 frame_type = SAME_FRAME_EXTENDED; /* 251*/
1.2341 + // u2 offset_delta;
1.2342 + // }
1.2343 + else if (frame_type == 251) {
1.2344 + stackmap_p += 2;
1.2345 + }
1.2346 +
1.2347 + // append_frame {
1.2348 + // u1 frame_type = APPEND; /* 252-254 */
1.2349 + // u2 offset_delta;
1.2350 + // verification_type_info locals[frame_type - 251];
1.2351 + // }
1.2352 + else if (frame_type >= 252 && frame_type <= 254) {
1.2353 + assert(stackmap_p + 2 <= stackmap_end,
1.2354 + "no room for offset_delta");
1.2355 + stackmap_p += 2;
1.2356 + u1 len = frame_type - 251;
1.2357 + for (u1 i = 0; i < len; i++) {
1.2358 + rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
1.2359 + calc_number_of_entries, frame_type, THREAD);
1.2360 + }
1.2361 + }
1.2362 +
1.2363 + // full_frame {
1.2364 + // u1 frame_type = FULL_FRAME; /* 255 */
1.2365 + // u2 offset_delta;
1.2366 + // u2 number_of_locals;
1.2367 + // verification_type_info locals[number_of_locals];
1.2368 + // u2 number_of_stack_items;
1.2369 + // verification_type_info stack[number_of_stack_items];
1.2370 + // }
1.2371 + else if (frame_type == 255) {
1.2372 + assert(stackmap_p + 2 + 2 <= stackmap_end,
1.2373 + "no room for smallest full_frame");
1.2374 + stackmap_p += 2;
1.2375 +
1.2376 + u2 number_of_locals = Bytes::get_Java_u2(stackmap_p);
1.2377 + stackmap_p += 2;
1.2378 +
1.2379 + for (u2 locals_i = 0; locals_i < number_of_locals; locals_i++) {
1.2380 + rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
1.2381 + calc_number_of_entries, frame_type, THREAD);
1.2382 + }
1.2383 +
1.2384 + // Use the largest size for the number_of_stack_items, but only get
1.2385 + // the right number of bytes.
1.2386 + u2 number_of_stack_items = Bytes::get_Java_u2(stackmap_p);
1.2387 + stackmap_p += 2;
1.2388 +
1.2389 + for (u2 stack_i = 0; stack_i < number_of_stack_items; stack_i++) {
1.2390 + rewrite_cp_refs_in_verification_type_info(stackmap_p, stackmap_end,
1.2391 + calc_number_of_entries, frame_type, THREAD);
1.2392 + }
1.2393 + }
1.2394 + } // end while there is a stack_map_frame
1.2395 + assert(number_of_entries == calc_number_of_entries, "sanity check");
1.2396 +} // end rewrite_cp_refs_in_stack_map_table()
1.2397 +
1.2398 +
1.2399 +// Rewrite constant pool references in the verification type info
1.2400 +// portion of the method's stackmap table. These "structures" are
1.2401 +// adapted from the StackMapTable_attribute that is described in
1.2402 +// section 4.8.4 of the 6.0 version of the VM spec (dated 2005.10.26):
1.2403 +// file:///net/quincunx.sfbay/export/gbracha/ClassFile-Java6.pdf
1.2404 +//
1.2405 +// The verification_type_info structure is a u1 tag followed by 0 or
1.2406 +// more bytes of data:
1.2407 +//
1.2408 +// union verification_type_info {
1.2409 +// Top_variable_info;
1.2410 +// Integer_variable_info;
1.2411 +// Float_variable_info;
1.2412 +// Long_variable_info;
1.2413 +// Double_variable_info;
1.2414 +// Null_variable_info;
1.2415 +// UninitializedThis_variable_info;
1.2416 +// Object_variable_info;
1.2417 +// Uninitialized_variable_info;
1.2418 +// }
1.2419 +//
1.2420 +void VM_RedefineClasses::rewrite_cp_refs_in_verification_type_info(
1.2421 + address& stackmap_p_ref, address stackmap_end, u2 frame_i,
1.2422 + u1 frame_type, TRAPS) {
1.2423 +
1.2424 + assert(stackmap_p_ref + 1 <= stackmap_end, "no room for tag");
1.2425 + u1 tag = *stackmap_p_ref;
1.2426 + stackmap_p_ref++;
1.2427 +
1.2428 + switch (tag) {
1.2429 + // Top_variable_info {
1.2430 + // u1 tag = ITEM_Top; /* 0 */
1.2431 + // }
1.2432 + // verificationType.hpp has zero as ITEM_Bogus instead of ITEM_Top
1.2433 + case 0: // fall through
1.2434 +
1.2435 + // Integer_variable_info {
1.2436 + // u1 tag = ITEM_Integer; /* 1 */
1.2437 + // }
1.2438 + case ITEM_Integer: // fall through
1.2439 +
1.2440 + // Float_variable_info {
1.2441 + // u1 tag = ITEM_Float; /* 2 */
1.2442 + // }
1.2443 + case ITEM_Float: // fall through
1.2444 +
1.2445 + // Double_variable_info {
1.2446 + // u1 tag = ITEM_Double; /* 3 */
1.2447 + // }
1.2448 + case ITEM_Double: // fall through
1.2449 +
1.2450 + // Long_variable_info {
1.2451 + // u1 tag = ITEM_Long; /* 4 */
1.2452 + // }
1.2453 + case ITEM_Long: // fall through
1.2454 +
1.2455 + // Null_variable_info {
1.2456 + // u1 tag = ITEM_Null; /* 5 */
1.2457 + // }
1.2458 + case ITEM_Null: // fall through
1.2459 +
1.2460 + // UninitializedThis_variable_info {
1.2461 + // u1 tag = ITEM_UninitializedThis; /* 6 */
1.2462 + // }
1.2463 + case ITEM_UninitializedThis:
1.2464 + // nothing more to do for the above tag types
1.2465 + break;
1.2466 +
1.2467 + // Object_variable_info {
1.2468 + // u1 tag = ITEM_Object; /* 7 */
1.2469 + // u2 cpool_index;
1.2470 + // }
1.2471 + case ITEM_Object:
1.2472 + {
1.2473 + assert(stackmap_p_ref + 2 <= stackmap_end, "no room for cpool_index");
1.2474 + u2 cpool_index = Bytes::get_Java_u2(stackmap_p_ref);
1.2475 + u2 new_cp_index = find_new_index(cpool_index);
1.2476 + if (new_cp_index != 0) {
1.2477 + RC_TRACE_WITH_THREAD(0x04000000, THREAD,
1.2478 + ("mapped old cpool_index=%d", cpool_index));
1.2479 + Bytes::put_Java_u2(stackmap_p_ref, new_cp_index);
1.2480 + cpool_index = new_cp_index;
1.2481 + }
1.2482 + stackmap_p_ref += 2;
1.2483 +
1.2484 + RC_TRACE_WITH_THREAD(0x04000000, THREAD,
1.2485 + ("frame_i=%u, frame_type=%u, cpool_index=%d", frame_i,
1.2486 + frame_type, cpool_index));
1.2487 + } break;
1.2488 +
1.2489 + // Uninitialized_variable_info {
1.2490 + // u1 tag = ITEM_Uninitialized; /* 8 */
1.2491 + // u2 offset;
1.2492 + // }
1.2493 + case ITEM_Uninitialized:
1.2494 + assert(stackmap_p_ref + 2 <= stackmap_end, "no room for offset");
1.2495 + stackmap_p_ref += 2;
1.2496 + break;
1.2497 +
1.2498 + default:
1.2499 + RC_TRACE_WITH_THREAD(0x04000000, THREAD,
1.2500 + ("frame_i=%u, frame_type=%u, bad tag=0x%x", frame_i, frame_type, tag));
1.2501 + ShouldNotReachHere();
1.2502 + break;
1.2503 + } // end switch (tag)
1.2504 +} // end rewrite_cp_refs_in_verification_type_info()
1.2505 +
1.2506 +
1.2507 +// Change the constant pool associated with klass scratch_class to
1.2508 +// scratch_cp. If shrink is true, then scratch_cp_length elements
1.2509 +// are copied from scratch_cp to a smaller constant pool and the
1.2510 +// smaller constant pool is associated with scratch_class.
1.2511 +void VM_RedefineClasses::set_new_constant_pool(
1.2512 + ClassLoaderData* loader_data,
1.2513 + instanceKlassHandle scratch_class, constantPoolHandle scratch_cp,
1.2514 + int scratch_cp_length, TRAPS) {
1.2515 + assert(scratch_cp->length() >= scratch_cp_length, "sanity check");
1.2516 +
1.2517 + // scratch_cp is a merged constant pool and has enough space for a
1.2518 + // worst case merge situation. We want to associate the minimum
1.2519 + // sized constant pool with the klass to save space.
1.2520 + ConstantPool* cp = ConstantPool::allocate(loader_data, scratch_cp_length, CHECK);
1.2521 + constantPoolHandle smaller_cp(THREAD, cp);
1.2522 +
1.2523 + // preserve version() value in the smaller copy
1.2524 + int version = scratch_cp->version();
1.2525 + assert(version != 0, "sanity check");
1.2526 + smaller_cp->set_version(version);
1.2527 +
1.2528 + // attach klass to new constant pool
1.2529 + // reference to the cp holder is needed for copy_operands()
1.2530 + smaller_cp->set_pool_holder(scratch_class());
1.2531 +
1.2532 + scratch_cp->copy_cp_to(1, scratch_cp_length - 1, smaller_cp, 1, THREAD);
1.2533 + if (HAS_PENDING_EXCEPTION) {
1.2534 + // Exception is handled in the caller
1.2535 + loader_data->add_to_deallocate_list(smaller_cp());
1.2536 + return;
1.2537 + }
1.2538 + scratch_cp = smaller_cp;
1.2539 +
1.2540 + // attach new constant pool to klass
1.2541 + scratch_class->set_constants(scratch_cp());
1.2542 +
1.2543 + int i; // for portability
1.2544 +
1.2545 + // update each field in klass to use new constant pool indices as needed
1.2546 + for (JavaFieldStream fs(scratch_class); !fs.done(); fs.next()) {
1.2547 + jshort cur_index = fs.name_index();
1.2548 + jshort new_index = find_new_index(cur_index);
1.2549 + if (new_index != 0) {
1.2550 + RC_TRACE_WITH_THREAD(0x00080000, THREAD,
1.2551 + ("field-name_index change: %d to %d", cur_index, new_index));
1.2552 + fs.set_name_index(new_index);
1.2553 + }
1.2554 + cur_index = fs.signature_index();
1.2555 + new_index = find_new_index(cur_index);
1.2556 + if (new_index != 0) {
1.2557 + RC_TRACE_WITH_THREAD(0x00080000, THREAD,
1.2558 + ("field-signature_index change: %d to %d", cur_index, new_index));
1.2559 + fs.set_signature_index(new_index);
1.2560 + }
1.2561 + cur_index = fs.initval_index();
1.2562 + new_index = find_new_index(cur_index);
1.2563 + if (new_index != 0) {
1.2564 + RC_TRACE_WITH_THREAD(0x00080000, THREAD,
1.2565 + ("field-initval_index change: %d to %d", cur_index, new_index));
1.2566 + fs.set_initval_index(new_index);
1.2567 + }
1.2568 + cur_index = fs.generic_signature_index();
1.2569 + new_index = find_new_index(cur_index);
1.2570 + if (new_index != 0) {
1.2571 + RC_TRACE_WITH_THREAD(0x00080000, THREAD,
1.2572 + ("field-generic_signature change: %d to %d", cur_index, new_index));
1.2573 + fs.set_generic_signature_index(new_index);
1.2574 + }
1.2575 + } // end for each field
1.2576 +
1.2577 + // Update constant pool indices in the inner classes info to use
1.2578 + // new constant indices as needed. The inner classes info is a
1.2579 + // quadruple:
1.2580 + // (inner_class_info, outer_class_info, inner_name, inner_access_flags)
1.2581 + InnerClassesIterator iter(scratch_class);
1.2582 + for (; !iter.done(); iter.next()) {
1.2583 + int cur_index = iter.inner_class_info_index();
1.2584 + if (cur_index == 0) {
1.2585 + continue; // JVM spec. allows null inner class refs so skip it
1.2586 + }
1.2587 + int new_index = find_new_index(cur_index);
1.2588 + if (new_index != 0) {
1.2589 + RC_TRACE_WITH_THREAD(0x00080000, THREAD,
1.2590 + ("inner_class_info change: %d to %d", cur_index, new_index));
1.2591 + iter.set_inner_class_info_index(new_index);
1.2592 + }
1.2593 + cur_index = iter.outer_class_info_index();
1.2594 + new_index = find_new_index(cur_index);
1.2595 + if (new_index != 0) {
1.2596 + RC_TRACE_WITH_THREAD(0x00080000, THREAD,
1.2597 + ("outer_class_info change: %d to %d", cur_index, new_index));
1.2598 + iter.set_outer_class_info_index(new_index);
1.2599 + }
1.2600 + cur_index = iter.inner_name_index();
1.2601 + new_index = find_new_index(cur_index);
1.2602 + if (new_index != 0) {
1.2603 + RC_TRACE_WITH_THREAD(0x00080000, THREAD,
1.2604 + ("inner_name change: %d to %d", cur_index, new_index));
1.2605 + iter.set_inner_name_index(new_index);
1.2606 + }
1.2607 + } // end for each inner class
1.2608 +
1.2609 + // Attach each method in klass to the new constant pool and update
1.2610 + // to use new constant pool indices as needed:
1.2611 + Array<Method*>* methods = scratch_class->methods();
1.2612 + for (i = methods->length() - 1; i >= 0; i--) {
1.2613 + methodHandle method(THREAD, methods->at(i));
1.2614 + method->set_constants(scratch_cp());
1.2615 +
1.2616 + int new_index = find_new_index(method->name_index());
1.2617 + if (new_index != 0) {
1.2618 + RC_TRACE_WITH_THREAD(0x00080000, THREAD,
1.2619 + ("method-name_index change: %d to %d", method->name_index(),
1.2620 + new_index));
1.2621 + method->set_name_index(new_index);
1.2622 + }
1.2623 + new_index = find_new_index(method->signature_index());
1.2624 + if (new_index != 0) {
1.2625 + RC_TRACE_WITH_THREAD(0x00080000, THREAD,
1.2626 + ("method-signature_index change: %d to %d",
1.2627 + method->signature_index(), new_index));
1.2628 + method->set_signature_index(new_index);
1.2629 + }
1.2630 + new_index = find_new_index(method->generic_signature_index());
1.2631 + if (new_index != 0) {
1.2632 + RC_TRACE_WITH_THREAD(0x00080000, THREAD,
1.2633 + ("method-generic_signature_index change: %d to %d",
1.2634 + method->generic_signature_index(), new_index));
1.2635 + method->set_generic_signature_index(new_index);
1.2636 + }
1.2637 +
1.2638 + // Update constant pool indices in the method's checked exception
1.2639 + // table to use new constant indices as needed.
1.2640 + int cext_length = method->checked_exceptions_length();
1.2641 + if (cext_length > 0) {
1.2642 + CheckedExceptionElement * cext_table =
1.2643 + method->checked_exceptions_start();
1.2644 + for (int j = 0; j < cext_length; j++) {
1.2645 + int cur_index = cext_table[j].class_cp_index;
1.2646 + int new_index = find_new_index(cur_index);
1.2647 + if (new_index != 0) {
1.2648 + RC_TRACE_WITH_THREAD(0x00080000, THREAD,
1.2649 + ("cext-class_cp_index change: %d to %d", cur_index, new_index));
1.2650 + cext_table[j].class_cp_index = (u2)new_index;
1.2651 + }
1.2652 + } // end for each checked exception table entry
1.2653 + } // end if there are checked exception table entries
1.2654 +
1.2655 + // Update each catch type index in the method's exception table
1.2656 + // to use new constant pool indices as needed. The exception table
1.2657 + // holds quadruple entries of the form:
1.2658 + // (beg_bci, end_bci, handler_bci, klass_index)
1.2659 +
1.2660 + ExceptionTable ex_table(method());
1.2661 + int ext_length = ex_table.length();
1.2662 +
1.2663 + for (int j = 0; j < ext_length; j ++) {
1.2664 + int cur_index = ex_table.catch_type_index(j);
1.2665 + int new_index = find_new_index(cur_index);
1.2666 + if (new_index != 0) {
1.2667 + RC_TRACE_WITH_THREAD(0x00080000, THREAD,
1.2668 + ("ext-klass_index change: %d to %d", cur_index, new_index));
1.2669 + ex_table.set_catch_type_index(j, new_index);
1.2670 + }
1.2671 + } // end for each exception table entry
1.2672 +
1.2673 + // Update constant pool indices in the method's local variable
1.2674 + // table to use new constant indices as needed. The local variable
1.2675 + // table hold sextuple entries of the form:
1.2676 + // (start_pc, length, name_index, descriptor_index, signature_index, slot)
1.2677 + int lvt_length = method->localvariable_table_length();
1.2678 + if (lvt_length > 0) {
1.2679 + LocalVariableTableElement * lv_table =
1.2680 + method->localvariable_table_start();
1.2681 + for (int j = 0; j < lvt_length; j++) {
1.2682 + int cur_index = lv_table[j].name_cp_index;
1.2683 + int new_index = find_new_index(cur_index);
1.2684 + if (new_index != 0) {
1.2685 + RC_TRACE_WITH_THREAD(0x00080000, THREAD,
1.2686 + ("lvt-name_cp_index change: %d to %d", cur_index, new_index));
1.2687 + lv_table[j].name_cp_index = (u2)new_index;
1.2688 + }
1.2689 + cur_index = lv_table[j].descriptor_cp_index;
1.2690 + new_index = find_new_index(cur_index);
1.2691 + if (new_index != 0) {
1.2692 + RC_TRACE_WITH_THREAD(0x00080000, THREAD,
1.2693 + ("lvt-descriptor_cp_index change: %d to %d", cur_index,
1.2694 + new_index));
1.2695 + lv_table[j].descriptor_cp_index = (u2)new_index;
1.2696 + }
1.2697 + cur_index = lv_table[j].signature_cp_index;
1.2698 + new_index = find_new_index(cur_index);
1.2699 + if (new_index != 0) {
1.2700 + RC_TRACE_WITH_THREAD(0x00080000, THREAD,
1.2701 + ("lvt-signature_cp_index change: %d to %d", cur_index, new_index));
1.2702 + lv_table[j].signature_cp_index = (u2)new_index;
1.2703 + }
1.2704 + } // end for each local variable table entry
1.2705 + } // end if there are local variable table entries
1.2706 +
1.2707 + rewrite_cp_refs_in_stack_map_table(method, THREAD);
1.2708 + } // end for each method
1.2709 +} // end set_new_constant_pool()
1.2710 +
1.2711 +
1.2712 +// Unevolving classes may point to methods of the_class directly
1.2713 +// from their constant pool caches, itables, and/or vtables. We
1.2714 +// use the ClassLoaderDataGraph::classes_do() facility and this helper
1.2715 +// to fix up these pointers.
1.2716 +
1.2717 +// Adjust cpools and vtables closure
1.2718 +void VM_RedefineClasses::AdjustCpoolCacheAndVtable::do_klass(Klass* k) {
1.2719 +
1.2720 + // This is a very busy routine. We don't want too much tracing
1.2721 + // printed out.
1.2722 + bool trace_name_printed = false;
1.2723 +
1.2724 + // Very noisy: only enable this call if you are trying to determine
1.2725 + // that a specific class gets found by this routine.
1.2726 + // RC_TRACE macro has an embedded ResourceMark
1.2727 + // RC_TRACE_WITH_THREAD(0x00100000, THREAD,
1.2728 + // ("adjust check: name=%s", k->external_name()));
1.2729 + // trace_name_printed = true;
1.2730 +
1.2731 + // If the class being redefined is java.lang.Object, we need to fix all
1.2732 + // array class vtables also
1.2733 + if (k->oop_is_array() && _the_class_oop == SystemDictionary::Object_klass()) {
1.2734 + k->vtable()->adjust_method_entries(_matching_old_methods,
1.2735 + _matching_new_methods,
1.2736 + _matching_methods_length,
1.2737 + &trace_name_printed);
1.2738 + } else if (k->oop_is_instance()) {
1.2739 + HandleMark hm(_thread);
1.2740 + InstanceKlass *ik = InstanceKlass::cast(k);
1.2741 +
1.2742 + // HotSpot specific optimization! HotSpot does not currently
1.2743 + // support delegation from the bootstrap class loader to a
1.2744 + // user-defined class loader. This means that if the bootstrap
1.2745 + // class loader is the initiating class loader, then it will also
1.2746 + // be the defining class loader. This also means that classes
1.2747 + // loaded by the bootstrap class loader cannot refer to classes
1.2748 + // loaded by a user-defined class loader. Note: a user-defined
1.2749 + // class loader can delegate to the bootstrap class loader.
1.2750 + //
1.2751 + // If the current class being redefined has a user-defined class
1.2752 + // loader as its defining class loader, then we can skip all
1.2753 + // classes loaded by the bootstrap class loader.
1.2754 + bool is_user_defined =
1.2755 + InstanceKlass::cast(_the_class_oop)->class_loader() != NULL;
1.2756 + if (is_user_defined && ik->class_loader() == NULL) {
1.2757 + return;
1.2758 + }
1.2759 +
1.2760 + // Fix the vtable embedded in the_class and subclasses of the_class,
1.2761 + // if one exists. We discard scratch_class and we don't keep an
1.2762 + // InstanceKlass around to hold obsolete methods so we don't have
1.2763 + // any other InstanceKlass embedded vtables to update. The vtable
1.2764 + // holds the Method*s for virtual (but not final) methods.
1.2765 + // Default methods, or concrete methods in interfaces are stored
1.2766 + // in the vtable, so if an interface changes we need to check
1.2767 + // adjust_method_entries() for every InstanceKlass, which will also
1.2768 + // adjust the default method vtable indices.
1.2769 + // We also need to adjust any default method entries that are
1.2770 + // not yet in the vtable, because the vtable setup is in progress.
1.2771 + // This must be done after we adjust the default_methods and
1.2772 + // default_vtable_indices for methods already in the vtable.
1.2773 + if (ik->vtable_length() > 0 && (_the_class_oop->is_interface()
1.2774 + || ik->is_subtype_of(_the_class_oop))) {
1.2775 + // ik->vtable() creates a wrapper object; rm cleans it up
1.2776 + ResourceMark rm(_thread);
1.2777 + ik->vtable()->adjust_method_entries(_matching_old_methods,
1.2778 + _matching_new_methods,
1.2779 + _matching_methods_length,
1.2780 + &trace_name_printed);
1.2781 + ik->adjust_default_methods(_matching_old_methods,
1.2782 + _matching_new_methods,
1.2783 + _matching_methods_length,
1.2784 + &trace_name_printed);
1.2785 + }
1.2786 +
1.2787 + // If the current class has an itable and we are either redefining an
1.2788 + // interface or if the current class is a subclass of the_class, then
1.2789 + // we potentially have to fix the itable. If we are redefining an
1.2790 + // interface, then we have to call adjust_method_entries() for
1.2791 + // every InstanceKlass that has an itable since there isn't a
1.2792 + // subclass relationship between an interface and an InstanceKlass.
1.2793 + if (ik->itable_length() > 0 && (_the_class_oop->is_interface()
1.2794 + || ik->is_subclass_of(_the_class_oop))) {
1.2795 + // ik->itable() creates a wrapper object; rm cleans it up
1.2796 + ResourceMark rm(_thread);
1.2797 + ik->itable()->adjust_method_entries(_matching_old_methods,
1.2798 + _matching_new_methods,
1.2799 + _matching_methods_length,
1.2800 + &trace_name_printed);
1.2801 + }
1.2802 +
1.2803 + // The constant pools in other classes (other_cp) can refer to
1.2804 + // methods in the_class. We have to update method information in
1.2805 + // other_cp's cache. If other_cp has a previous version, then we
1.2806 + // have to repeat the process for each previous version. The
1.2807 + // constant pool cache holds the Method*s for non-virtual
1.2808 + // methods and for virtual, final methods.
1.2809 + //
1.2810 + // Special case: if the current class is the_class, then new_cp
1.2811 + // has already been attached to the_class and old_cp has already
1.2812 + // been added as a previous version. The new_cp doesn't have any
1.2813 + // cached references to old methods so it doesn't need to be
1.2814 + // updated. We can simply start with the previous version(s) in
1.2815 + // that case.
1.2816 + constantPoolHandle other_cp;
1.2817 + ConstantPoolCache* cp_cache;
1.2818 +
1.2819 + if (ik != _the_class_oop) {
1.2820 + // this klass' constant pool cache may need adjustment
1.2821 + other_cp = constantPoolHandle(ik->constants());
1.2822 + cp_cache = other_cp->cache();
1.2823 + if (cp_cache != NULL) {
1.2824 + cp_cache->adjust_method_entries(_matching_old_methods,
1.2825 + _matching_new_methods,
1.2826 + _matching_methods_length,
1.2827 + &trace_name_printed);
1.2828 + }
1.2829 + }
1.2830 +
1.2831 + // the previous versions' constant pool caches may need adjustment
1.2832 + PreviousVersionWalker pvw(_thread, ik);
1.2833 + for (PreviousVersionNode * pv_node = pvw.next_previous_version();
1.2834 + pv_node != NULL; pv_node = pvw.next_previous_version()) {
1.2835 + other_cp = pv_node->prev_constant_pool();
1.2836 + cp_cache = other_cp->cache();
1.2837 + if (cp_cache != NULL) {
1.2838 + cp_cache->adjust_method_entries(_matching_old_methods,
1.2839 + _matching_new_methods,
1.2840 + _matching_methods_length,
1.2841 + &trace_name_printed);
1.2842 + }
1.2843 + }
1.2844 + }
1.2845 +}
1.2846 +
1.2847 +void VM_RedefineClasses::update_jmethod_ids() {
1.2848 + for (int j = 0; j < _matching_methods_length; ++j) {
1.2849 + Method* old_method = _matching_old_methods[j];
1.2850 + jmethodID jmid = old_method->find_jmethod_id_or_null();
1.2851 + if (jmid != NULL) {
1.2852 + // There is a jmethodID, change it to point to the new method
1.2853 + methodHandle new_method_h(_matching_new_methods[j]);
1.2854 + Method::change_method_associated_with_jmethod_id(jmid, new_method_h());
1.2855 + assert(Method::resolve_jmethod_id(jmid) == _matching_new_methods[j],
1.2856 + "should be replaced");
1.2857 + }
1.2858 + }
1.2859 +}
1.2860 +
1.2861 +void VM_RedefineClasses::check_methods_and_mark_as_obsolete(
1.2862 + BitMap *emcp_methods, int * emcp_method_count_p) {
1.2863 + *emcp_method_count_p = 0;
1.2864 + int obsolete_count = 0;
1.2865 + int old_index = 0;
1.2866 + for (int j = 0; j < _matching_methods_length; ++j, ++old_index) {
1.2867 + Method* old_method = _matching_old_methods[j];
1.2868 + Method* new_method = _matching_new_methods[j];
1.2869 + Method* old_array_method;
1.2870 +
1.2871 + // Maintain an old_index into the _old_methods array by skipping
1.2872 + // deleted methods
1.2873 + while ((old_array_method = _old_methods->at(old_index)) != old_method) {
1.2874 + ++old_index;
1.2875 + }
1.2876 +
1.2877 + if (MethodComparator::methods_EMCP(old_method, new_method)) {
1.2878 + // The EMCP definition from JSR-163 requires the bytecodes to be
1.2879 + // the same with the exception of constant pool indices which may
1.2880 + // differ. However, the constants referred to by those indices
1.2881 + // must be the same.
1.2882 + //
1.2883 + // We use methods_EMCP() for comparison since constant pool
1.2884 + // merging can remove duplicate constant pool entries that were
1.2885 + // present in the old method and removed from the rewritten new
1.2886 + // method. A faster binary comparison function would consider the
1.2887 + // old and new methods to be different when they are actually
1.2888 + // EMCP.
1.2889 + //
1.2890 + // The old and new methods are EMCP and you would think that we
1.2891 + // could get rid of one of them here and now and save some space.
1.2892 + // However, the concept of EMCP only considers the bytecodes and
1.2893 + // the constant pool entries in the comparison. Other things,
1.2894 + // e.g., the line number table (LNT) or the local variable table
1.2895 + // (LVT) don't count in the comparison. So the new (and EMCP)
1.2896 + // method can have a new LNT that we need so we can't just
1.2897 + // overwrite the new method with the old method.
1.2898 + //
1.2899 + // When this routine is called, we have already attached the new
1.2900 + // methods to the_class so the old methods are effectively
1.2901 + // overwritten. However, if an old method is still executing,
1.2902 + // then the old method cannot be collected until sometime after
1.2903 + // the old method call has returned. So the overwriting of old
1.2904 + // methods by new methods will save us space except for those
1.2905 + // (hopefully few) old methods that are still executing.
1.2906 + //
1.2907 + // A method refers to a ConstMethod* and this presents another
1.2908 + // possible avenue to space savings. The ConstMethod* in the
1.2909 + // new method contains possibly new attributes (LNT, LVT, etc).
1.2910 + // At first glance, it seems possible to save space by replacing
1.2911 + // the ConstMethod* in the old method with the ConstMethod*
1.2912 + // from the new method. The old and new methods would share the
1.2913 + // same ConstMethod* and we would save the space occupied by
1.2914 + // the old ConstMethod*. However, the ConstMethod* contains
1.2915 + // a back reference to the containing method. Sharing the
1.2916 + // ConstMethod* between two methods could lead to confusion in
1.2917 + // the code that uses the back reference. This would lead to
1.2918 + // brittle code that could be broken in non-obvious ways now or
1.2919 + // in the future.
1.2920 + //
1.2921 + // Another possibility is to copy the ConstMethod* from the new
1.2922 + // method to the old method and then overwrite the new method with
1.2923 + // the old method. Since the ConstMethod* contains the bytecodes
1.2924 + // for the method embedded in the oop, this option would change
1.2925 + // the bytecodes out from under any threads executing the old
1.2926 + // method and make the thread's bcp invalid. Since EMCP requires
1.2927 + // that the bytecodes be the same modulo constant pool indices, it
1.2928 + // is straight forward to compute the correct new bcp in the new
1.2929 + // ConstMethod* from the old bcp in the old ConstMethod*. The
1.2930 + // time consuming part would be searching all the frames in all
1.2931 + // of the threads to find all of the calls to the old method.
1.2932 + //
1.2933 + // It looks like we will have to live with the limited savings
1.2934 + // that we get from effectively overwriting the old methods
1.2935 + // when the new methods are attached to the_class.
1.2936 +
1.2937 + // track which methods are EMCP for add_previous_version() call
1.2938 + emcp_methods->set_bit(old_index);
1.2939 + (*emcp_method_count_p)++;
1.2940 +
1.2941 + // An EMCP method is _not_ obsolete. An obsolete method has a
1.2942 + // different jmethodID than the current method. An EMCP method
1.2943 + // has the same jmethodID as the current method. Having the
1.2944 + // same jmethodID for all EMCP versions of a method allows for
1.2945 + // a consistent view of the EMCP methods regardless of which
1.2946 + // EMCP method you happen to have in hand. For example, a
1.2947 + // breakpoint set in one EMCP method will work for all EMCP
1.2948 + // versions of the method including the current one.
1.2949 + } else {
1.2950 + // mark obsolete methods as such
1.2951 + old_method->set_is_obsolete();
1.2952 + obsolete_count++;
1.2953 +
1.2954 + // obsolete methods need a unique idnum so they become new entries in
1.2955 + // the jmethodID cache in InstanceKlass
1.2956 + u2 num = InstanceKlass::cast(_the_class_oop)->next_method_idnum();
1.2957 + if (num != ConstMethod::UNSET_IDNUM) {
1.2958 + old_method->set_method_idnum(num);
1.2959 + }
1.2960 +
1.2961 + // With tracing we try not to "yack" too much. The position of
1.2962 + // this trace assumes there are fewer obsolete methods than
1.2963 + // EMCP methods.
1.2964 + RC_TRACE(0x00000100, ("mark %s(%s) as obsolete",
1.2965 + old_method->name()->as_C_string(),
1.2966 + old_method->signature()->as_C_string()));
1.2967 + }
1.2968 + old_method->set_is_old();
1.2969 + }
1.2970 + for (int i = 0; i < _deleted_methods_length; ++i) {
1.2971 + Method* old_method = _deleted_methods[i];
1.2972 +
1.2973 + assert(!old_method->has_vtable_index(),
1.2974 + "cannot delete methods with vtable entries");;
1.2975 +
1.2976 + // Mark all deleted methods as old and obsolete
1.2977 + old_method->set_is_old();
1.2978 + old_method->set_is_obsolete();
1.2979 + ++obsolete_count;
1.2980 + // With tracing we try not to "yack" too much. The position of
1.2981 + // this trace assumes there are fewer obsolete methods than
1.2982 + // EMCP methods.
1.2983 + RC_TRACE(0x00000100, ("mark deleted %s(%s) as obsolete",
1.2984 + old_method->name()->as_C_string(),
1.2985 + old_method->signature()->as_C_string()));
1.2986 + }
1.2987 + assert((*emcp_method_count_p + obsolete_count) == _old_methods->length(),
1.2988 + "sanity check");
1.2989 + RC_TRACE(0x00000100, ("EMCP_cnt=%d, obsolete_cnt=%d", *emcp_method_count_p,
1.2990 + obsolete_count));
1.2991 +}
1.2992 +
1.2993 +// This internal class transfers the native function registration from old methods
1.2994 +// to new methods. It is designed to handle both the simple case of unchanged
1.2995 +// native methods and the complex cases of native method prefixes being added and/or
1.2996 +// removed.
1.2997 +// It expects only to be used during the VM_RedefineClasses op (a safepoint).
1.2998 +//
1.2999 +// This class is used after the new methods have been installed in "the_class".
1.3000 +//
1.3001 +// So, for example, the following must be handled. Where 'm' is a method and
1.3002 +// a number followed by an underscore is a prefix.
1.3003 +//
1.3004 +// Old Name New Name
1.3005 +// Simple transfer to new method m -> m
1.3006 +// Add prefix m -> 1_m
1.3007 +// Remove prefix 1_m -> m
1.3008 +// Simultaneous add of prefixes m -> 3_2_1_m
1.3009 +// Simultaneous removal of prefixes 3_2_1_m -> m
1.3010 +// Simultaneous add and remove 1_m -> 2_m
1.3011 +// Same, caused by prefix removal only 3_2_1_m -> 3_2_m
1.3012 +//
1.3013 +class TransferNativeFunctionRegistration {
1.3014 + private:
1.3015 + instanceKlassHandle the_class;
1.3016 + int prefix_count;
1.3017 + char** prefixes;
1.3018 +
1.3019 + // Recursively search the binary tree of possibly prefixed method names.
1.3020 + // Iteration could be used if all agents were well behaved. Full tree walk is
1.3021 + // more resilent to agents not cleaning up intermediate methods.
1.3022 + // Branch at each depth in the binary tree is:
1.3023 + // (1) without the prefix.
1.3024 + // (2) with the prefix.
1.3025 + // where 'prefix' is the prefix at that 'depth' (first prefix, second prefix,...)
1.3026 + Method* search_prefix_name_space(int depth, char* name_str, size_t name_len,
1.3027 + Symbol* signature) {
1.3028 + TempNewSymbol name_symbol = SymbolTable::probe(name_str, (int)name_len);
1.3029 + if (name_symbol != NULL) {
1.3030 + Method* method = the_class()->lookup_method(name_symbol, signature);
1.3031 + if (method != NULL) {
1.3032 + // Even if prefixed, intermediate methods must exist.
1.3033 + if (method->is_native()) {
1.3034 + // Wahoo, we found a (possibly prefixed) version of the method, return it.
1.3035 + return method;
1.3036 + }
1.3037 + if (depth < prefix_count) {
1.3038 + // Try applying further prefixes (other than this one).
1.3039 + method = search_prefix_name_space(depth+1, name_str, name_len, signature);
1.3040 + if (method != NULL) {
1.3041 + return method; // found
1.3042 + }
1.3043 +
1.3044 + // Try adding this prefix to the method name and see if it matches
1.3045 + // another method name.
1.3046 + char* prefix = prefixes[depth];
1.3047 + size_t prefix_len = strlen(prefix);
1.3048 + size_t trial_len = name_len + prefix_len;
1.3049 + char* trial_name_str = NEW_RESOURCE_ARRAY(char, trial_len + 1);
1.3050 + strcpy(trial_name_str, prefix);
1.3051 + strcat(trial_name_str, name_str);
1.3052 + method = search_prefix_name_space(depth+1, trial_name_str, trial_len,
1.3053 + signature);
1.3054 + if (method != NULL) {
1.3055 + // If found along this branch, it was prefixed, mark as such
1.3056 + method->set_is_prefixed_native();
1.3057 + return method; // found
1.3058 + }
1.3059 + }
1.3060 + }
1.3061 + }
1.3062 + return NULL; // This whole branch bore nothing
1.3063 + }
1.3064 +
1.3065 + // Return the method name with old prefixes stripped away.
1.3066 + char* method_name_without_prefixes(Method* method) {
1.3067 + Symbol* name = method->name();
1.3068 + char* name_str = name->as_utf8();
1.3069 +
1.3070 + // Old prefixing may be defunct, strip prefixes, if any.
1.3071 + for (int i = prefix_count-1; i >= 0; i--) {
1.3072 + char* prefix = prefixes[i];
1.3073 + size_t prefix_len = strlen(prefix);
1.3074 + if (strncmp(prefix, name_str, prefix_len) == 0) {
1.3075 + name_str += prefix_len;
1.3076 + }
1.3077 + }
1.3078 + return name_str;
1.3079 + }
1.3080 +
1.3081 + // Strip any prefixes off the old native method, then try to find a
1.3082 + // (possibly prefixed) new native that matches it.
1.3083 + Method* strip_and_search_for_new_native(Method* method) {
1.3084 + ResourceMark rm;
1.3085 + char* name_str = method_name_without_prefixes(method);
1.3086 + return search_prefix_name_space(0, name_str, strlen(name_str),
1.3087 + method->signature());
1.3088 + }
1.3089 +
1.3090 + public:
1.3091 +
1.3092 + // Construct a native method transfer processor for this class.
1.3093 + TransferNativeFunctionRegistration(instanceKlassHandle _the_class) {
1.3094 + assert(SafepointSynchronize::is_at_safepoint(), "sanity check");
1.3095 +
1.3096 + the_class = _the_class;
1.3097 + prefixes = JvmtiExport::get_all_native_method_prefixes(&prefix_count);
1.3098 + }
1.3099 +
1.3100 + // Attempt to transfer any of the old or deleted methods that are native
1.3101 + void transfer_registrations(Method** old_methods, int methods_length) {
1.3102 + for (int j = 0; j < methods_length; j++) {
1.3103 + Method* old_method = old_methods[j];
1.3104 +
1.3105 + if (old_method->is_native() && old_method->has_native_function()) {
1.3106 + Method* new_method = strip_and_search_for_new_native(old_method);
1.3107 + if (new_method != NULL) {
1.3108 + // Actually set the native function in the new method.
1.3109 + // Redefine does not send events (except CFLH), certainly not this
1.3110 + // behind the scenes re-registration.
1.3111 + new_method->set_native_function(old_method->native_function(),
1.3112 + !Method::native_bind_event_is_interesting);
1.3113 + }
1.3114 + }
1.3115 + }
1.3116 + }
1.3117 +};
1.3118 +
1.3119 +// Don't lose the association between a native method and its JNI function.
1.3120 +void VM_RedefineClasses::transfer_old_native_function_registrations(instanceKlassHandle the_class) {
1.3121 + TransferNativeFunctionRegistration transfer(the_class);
1.3122 + transfer.transfer_registrations(_deleted_methods, _deleted_methods_length);
1.3123 + transfer.transfer_registrations(_matching_old_methods, _matching_methods_length);
1.3124 +}
1.3125 +
1.3126 +// Deoptimize all compiled code that depends on this class.
1.3127 +//
1.3128 +// If the can_redefine_classes capability is obtained in the onload
1.3129 +// phase then the compiler has recorded all dependencies from startup.
1.3130 +// In that case we need only deoptimize and throw away all compiled code
1.3131 +// that depends on the class.
1.3132 +//
1.3133 +// If can_redefine_classes is obtained sometime after the onload
1.3134 +// phase then the dependency information may be incomplete. In that case
1.3135 +// the first call to RedefineClasses causes all compiled code to be
1.3136 +// thrown away. As can_redefine_classes has been obtained then
1.3137 +// all future compilations will record dependencies so second and
1.3138 +// subsequent calls to RedefineClasses need only throw away code
1.3139 +// that depends on the class.
1.3140 +//
1.3141 +void VM_RedefineClasses::flush_dependent_code(instanceKlassHandle k_h, TRAPS) {
1.3142 + assert_locked_or_safepoint(Compile_lock);
1.3143 +
1.3144 + // All dependencies have been recorded from startup or this is a second or
1.3145 + // subsequent use of RedefineClasses
1.3146 + if (JvmtiExport::all_dependencies_are_recorded()) {
1.3147 + Universe::flush_evol_dependents_on(k_h);
1.3148 + } else {
1.3149 + CodeCache::mark_all_nmethods_for_deoptimization();
1.3150 +
1.3151 + ResourceMark rm(THREAD);
1.3152 + DeoptimizationMarker dm;
1.3153 +
1.3154 + // Deoptimize all activations depending on marked nmethods
1.3155 + Deoptimization::deoptimize_dependents();
1.3156 +
1.3157 + // Make the dependent methods not entrant (in VM_Deoptimize they are made zombies)
1.3158 + CodeCache::make_marked_nmethods_not_entrant();
1.3159 +
1.3160 + // From now on we know that the dependency information is complete
1.3161 + JvmtiExport::set_all_dependencies_are_recorded(true);
1.3162 + }
1.3163 +}
1.3164 +
1.3165 +void VM_RedefineClasses::compute_added_deleted_matching_methods() {
1.3166 + Method* old_method;
1.3167 + Method* new_method;
1.3168 +
1.3169 + _matching_old_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
1.3170 + _matching_new_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
1.3171 + _added_methods = NEW_RESOURCE_ARRAY(Method*, _new_methods->length());
1.3172 + _deleted_methods = NEW_RESOURCE_ARRAY(Method*, _old_methods->length());
1.3173 +
1.3174 + _matching_methods_length = 0;
1.3175 + _deleted_methods_length = 0;
1.3176 + _added_methods_length = 0;
1.3177 +
1.3178 + int nj = 0;
1.3179 + int oj = 0;
1.3180 + while (true) {
1.3181 + if (oj >= _old_methods->length()) {
1.3182 + if (nj >= _new_methods->length()) {
1.3183 + break; // we've looked at everything, done
1.3184 + }
1.3185 + // New method at the end
1.3186 + new_method = _new_methods->at(nj);
1.3187 + _added_methods[_added_methods_length++] = new_method;
1.3188 + ++nj;
1.3189 + } else if (nj >= _new_methods->length()) {
1.3190 + // Old method, at the end, is deleted
1.3191 + old_method = _old_methods->at(oj);
1.3192 + _deleted_methods[_deleted_methods_length++] = old_method;
1.3193 + ++oj;
1.3194 + } else {
1.3195 + old_method = _old_methods->at(oj);
1.3196 + new_method = _new_methods->at(nj);
1.3197 + if (old_method->name() == new_method->name()) {
1.3198 + if (old_method->signature() == new_method->signature()) {
1.3199 + _matching_old_methods[_matching_methods_length ] = old_method;
1.3200 + _matching_new_methods[_matching_methods_length++] = new_method;
1.3201 + ++nj;
1.3202 + ++oj;
1.3203 + } else {
1.3204 + // added overloaded have already been moved to the end,
1.3205 + // so this is a deleted overloaded method
1.3206 + _deleted_methods[_deleted_methods_length++] = old_method;
1.3207 + ++oj;
1.3208 + }
1.3209 + } else { // names don't match
1.3210 + if (old_method->name()->fast_compare(new_method->name()) > 0) {
1.3211 + // new method
1.3212 + _added_methods[_added_methods_length++] = new_method;
1.3213 + ++nj;
1.3214 + } else {
1.3215 + // deleted method
1.3216 + _deleted_methods[_deleted_methods_length++] = old_method;
1.3217 + ++oj;
1.3218 + }
1.3219 + }
1.3220 + }
1.3221 + }
1.3222 + assert(_matching_methods_length + _deleted_methods_length == _old_methods->length(), "sanity");
1.3223 + assert(_matching_methods_length + _added_methods_length == _new_methods->length(), "sanity");
1.3224 +}
1.3225 +
1.3226 +
1.3227 +void VM_RedefineClasses::swap_annotations(instanceKlassHandle the_class,
1.3228 + instanceKlassHandle scratch_class) {
1.3229 + // Since there is currently no rewriting of type annotations indexes
1.3230 + // into the CP, we null out type annotations on scratch_class before
1.3231 + // we swap annotations with the_class rather than facing the
1.3232 + // possibility of shipping annotations with broken indexes to
1.3233 + // Java-land.
1.3234 + ClassLoaderData* loader_data = scratch_class->class_loader_data();
1.3235 + AnnotationArray* new_class_type_annotations = scratch_class->class_type_annotations();
1.3236 + if (new_class_type_annotations != NULL) {
1.3237 + MetadataFactory::free_array<u1>(loader_data, new_class_type_annotations);
1.3238 + scratch_class->annotations()->set_class_type_annotations(NULL);
1.3239 + }
1.3240 + Array<AnnotationArray*>* new_field_type_annotations = scratch_class->fields_type_annotations();
1.3241 + if (new_field_type_annotations != NULL) {
1.3242 + Annotations::free_contents(loader_data, new_field_type_annotations);
1.3243 + scratch_class->annotations()->set_fields_type_annotations(NULL);
1.3244 + }
1.3245 +
1.3246 + // Swap annotation fields values
1.3247 + Annotations* old_annotations = the_class->annotations();
1.3248 + the_class->set_annotations(scratch_class->annotations());
1.3249 + scratch_class->set_annotations(old_annotations);
1.3250 +}
1.3251 +
1.3252 +
1.3253 +// Install the redefinition of a class:
1.3254 +// - house keeping (flushing breakpoints and caches, deoptimizing
1.3255 +// dependent compiled code)
1.3256 +// - replacing parts in the_class with parts from scratch_class
1.3257 +// - adding a weak reference to track the obsolete but interesting
1.3258 +// parts of the_class
1.3259 +// - adjusting constant pool caches and vtables in other classes
1.3260 +// that refer to methods in the_class. These adjustments use the
1.3261 +// ClassLoaderDataGraph::classes_do() facility which only allows
1.3262 +// a helper method to be specified. The interesting parameters
1.3263 +// that we would like to pass to the helper method are saved in
1.3264 +// static global fields in the VM operation.
1.3265 +void VM_RedefineClasses::redefine_single_class(jclass the_jclass,
1.3266 + Klass* scratch_class_oop, TRAPS) {
1.3267 +
1.3268 + HandleMark hm(THREAD); // make sure handles from this call are freed
1.3269 + RC_TIMER_START(_timer_rsc_phase1);
1.3270 +
1.3271 + instanceKlassHandle scratch_class(scratch_class_oop);
1.3272 +
1.3273 + oop the_class_mirror = JNIHandles::resolve_non_null(the_jclass);
1.3274 + Klass* the_class_oop = java_lang_Class::as_Klass(the_class_mirror);
1.3275 + instanceKlassHandle the_class = instanceKlassHandle(THREAD, the_class_oop);
1.3276 +
1.3277 + // Remove all breakpoints in methods of this class
1.3278 + JvmtiBreakpoints& jvmti_breakpoints = JvmtiCurrentBreakpoints::get_jvmti_breakpoints();
1.3279 + jvmti_breakpoints.clearall_in_class_at_safepoint(the_class_oop);
1.3280 +
1.3281 + // Deoptimize all compiled code that depends on this class
1.3282 + flush_dependent_code(the_class, THREAD);
1.3283 +
1.3284 + _old_methods = the_class->methods();
1.3285 + _new_methods = scratch_class->methods();
1.3286 + _the_class_oop = the_class_oop;
1.3287 + compute_added_deleted_matching_methods();
1.3288 + update_jmethod_ids();
1.3289 +
1.3290 + // Attach new constant pool to the original klass. The original
1.3291 + // klass still refers to the old constant pool (for now).
1.3292 + scratch_class->constants()->set_pool_holder(the_class());
1.3293 +
1.3294 +#if 0
1.3295 + // In theory, with constant pool merging in place we should be able
1.3296 + // to save space by using the new, merged constant pool in place of
1.3297 + // the old constant pool(s). By "pool(s)" I mean the constant pool in
1.3298 + // the klass version we are replacing now and any constant pool(s) in
1.3299 + // previous versions of klass. Nice theory, doesn't work in practice.
1.3300 + // When this code is enabled, even simple programs throw NullPointer
1.3301 + // exceptions. I'm guessing that this is caused by some constant pool
1.3302 + // cache difference between the new, merged constant pool and the
1.3303 + // constant pool that was just being used by the klass. I'm keeping
1.3304 + // this code around to archive the idea, but the code has to remain
1.3305 + // disabled for now.
1.3306 +
1.3307 + // Attach each old method to the new constant pool. This can be
1.3308 + // done here since we are past the bytecode verification and
1.3309 + // constant pool optimization phases.
1.3310 + for (int i = _old_methods->length() - 1; i >= 0; i--) {
1.3311 + Method* method = _old_methods->at(i);
1.3312 + method->set_constants(scratch_class->constants());
1.3313 + }
1.3314 +
1.3315 + {
1.3316 + // walk all previous versions of the klass
1.3317 + InstanceKlass *ik = (InstanceKlass *)the_class();
1.3318 + PreviousVersionWalker pvw(ik);
1.3319 + instanceKlassHandle ikh;
1.3320 + do {
1.3321 + ikh = pvw.next_previous_version();
1.3322 + if (!ikh.is_null()) {
1.3323 + ik = ikh();
1.3324 +
1.3325 + // attach previous version of klass to the new constant pool
1.3326 + ik->set_constants(scratch_class->constants());
1.3327 +
1.3328 + // Attach each method in the previous version of klass to the
1.3329 + // new constant pool
1.3330 + Array<Method*>* prev_methods = ik->methods();
1.3331 + for (int i = prev_methods->length() - 1; i >= 0; i--) {
1.3332 + Method* method = prev_methods->at(i);
1.3333 + method->set_constants(scratch_class->constants());
1.3334 + }
1.3335 + }
1.3336 + } while (!ikh.is_null());
1.3337 + }
1.3338 +#endif
1.3339 +
1.3340 + // Replace methods and constantpool
1.3341 + the_class->set_methods(_new_methods);
1.3342 + scratch_class->set_methods(_old_methods); // To prevent potential GCing of the old methods,
1.3343 + // and to be able to undo operation easily.
1.3344 +
1.3345 + ConstantPool* old_constants = the_class->constants();
1.3346 + the_class->set_constants(scratch_class->constants());
1.3347 + scratch_class->set_constants(old_constants); // See the previous comment.
1.3348 +#if 0
1.3349 + // We are swapping the guts of "the new class" with the guts of "the
1.3350 + // class". Since the old constant pool has just been attached to "the
1.3351 + // new class", it seems logical to set the pool holder in the old
1.3352 + // constant pool also. However, doing this will change the observable
1.3353 + // class hierarchy for any old methods that are still executing. A
1.3354 + // method can query the identity of its "holder" and this query uses
1.3355 + // the method's constant pool link to find the holder. The change in
1.3356 + // holding class from "the class" to "the new class" can confuse
1.3357 + // things.
1.3358 + //
1.3359 + // Setting the old constant pool's holder will also cause
1.3360 + // verification done during vtable initialization below to fail.
1.3361 + // During vtable initialization, the vtable's class is verified to be
1.3362 + // a subtype of the method's holder. The vtable's class is "the
1.3363 + // class" and the method's holder is gotten from the constant pool
1.3364 + // link in the method itself. For "the class"'s directly implemented
1.3365 + // methods, the method holder is "the class" itself (as gotten from
1.3366 + // the new constant pool). The check works fine in this case. The
1.3367 + // check also works fine for methods inherited from super classes.
1.3368 + //
1.3369 + // Miranda methods are a little more complicated. A miranda method is
1.3370 + // provided by an interface when the class implementing the interface
1.3371 + // does not provide its own method. These interfaces are implemented
1.3372 + // internally as an InstanceKlass. These special instanceKlasses
1.3373 + // share the constant pool of the class that "implements" the
1.3374 + // interface. By sharing the constant pool, the method holder of a
1.3375 + // miranda method is the class that "implements" the interface. In a
1.3376 + // non-redefine situation, the subtype check works fine. However, if
1.3377 + // the old constant pool's pool holder is modified, then the check
1.3378 + // fails because there is no class hierarchy relationship between the
1.3379 + // vtable's class and "the new class".
1.3380 +
1.3381 + old_constants->set_pool_holder(scratch_class());
1.3382 +#endif
1.3383 +
1.3384 + // track which methods are EMCP for add_previous_version() call below
1.3385 + BitMap emcp_methods(_old_methods->length());
1.3386 + int emcp_method_count = 0;
1.3387 + emcp_methods.clear(); // clears 0..(length() - 1)
1.3388 + check_methods_and_mark_as_obsolete(&emcp_methods, &emcp_method_count);
1.3389 + transfer_old_native_function_registrations(the_class);
1.3390 +
1.3391 + // The class file bytes from before any retransformable agents mucked
1.3392 + // with them was cached on the scratch class, move to the_class.
1.3393 + // Note: we still want to do this if nothing needed caching since it
1.3394 + // should get cleared in the_class too.
1.3395 + if (the_class->get_cached_class_file_bytes() == 0) {
1.3396 + // the_class doesn't have a cache yet so copy it
1.3397 + the_class->set_cached_class_file(scratch_class->get_cached_class_file());
1.3398 + }
1.3399 +#ifndef PRODUCT
1.3400 + else {
1.3401 + assert(the_class->get_cached_class_file_bytes() ==
1.3402 + scratch_class->get_cached_class_file_bytes(), "cache ptrs must match");
1.3403 + assert(the_class->get_cached_class_file_len() ==
1.3404 + scratch_class->get_cached_class_file_len(), "cache lens must match");
1.3405 + }
1.3406 +#endif
1.3407 +
1.3408 + // NULL out in scratch class to not delete twice. The class to be redefined
1.3409 + // always owns these bytes.
1.3410 + scratch_class->set_cached_class_file(NULL);
1.3411 +
1.3412 + // Replace inner_classes
1.3413 + Array<u2>* old_inner_classes = the_class->inner_classes();
1.3414 + the_class->set_inner_classes(scratch_class->inner_classes());
1.3415 + scratch_class->set_inner_classes(old_inner_classes);
1.3416 +
1.3417 + // Initialize the vtable and interface table after
1.3418 + // methods have been rewritten
1.3419 + {
1.3420 + ResourceMark rm(THREAD);
1.3421 + // no exception should happen here since we explicitly
1.3422 + // do not check loader constraints.
1.3423 + // compare_and_normalize_class_versions has already checked:
1.3424 + // - classloaders unchanged, signatures unchanged
1.3425 + // - all instanceKlasses for redefined classes reused & contents updated
1.3426 + the_class->vtable()->initialize_vtable(false, THREAD);
1.3427 + the_class->itable()->initialize_itable(false, THREAD);
1.3428 + assert(!HAS_PENDING_EXCEPTION || (THREAD->pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())), "redefine exception");
1.3429 + }
1.3430 +
1.3431 + // Leave arrays of jmethodIDs and itable index cache unchanged
1.3432 +
1.3433 + // Copy the "source file name" attribute from new class version
1.3434 + the_class->set_source_file_name_index(
1.3435 + scratch_class->source_file_name_index());
1.3436 +
1.3437 + // Copy the "source debug extension" attribute from new class version
1.3438 + the_class->set_source_debug_extension(
1.3439 + scratch_class->source_debug_extension(),
1.3440 + scratch_class->source_debug_extension() == NULL ? 0 :
1.3441 + (int)strlen(scratch_class->source_debug_extension()));
1.3442 +
1.3443 + // Use of javac -g could be different in the old and the new
1.3444 + if (scratch_class->access_flags().has_localvariable_table() !=
1.3445 + the_class->access_flags().has_localvariable_table()) {
1.3446 +
1.3447 + AccessFlags flags = the_class->access_flags();
1.3448 + if (scratch_class->access_flags().has_localvariable_table()) {
1.3449 + flags.set_has_localvariable_table();
1.3450 + } else {
1.3451 + flags.clear_has_localvariable_table();
1.3452 + }
1.3453 + the_class->set_access_flags(flags);
1.3454 + }
1.3455 +
1.3456 + swap_annotations(the_class, scratch_class);
1.3457 +
1.3458 + // Replace minor version number of class file
1.3459 + u2 old_minor_version = the_class->minor_version();
1.3460 + the_class->set_minor_version(scratch_class->minor_version());
1.3461 + scratch_class->set_minor_version(old_minor_version);
1.3462 +
1.3463 + // Replace major version number of class file
1.3464 + u2 old_major_version = the_class->major_version();
1.3465 + the_class->set_major_version(scratch_class->major_version());
1.3466 + scratch_class->set_major_version(old_major_version);
1.3467 +
1.3468 + // Replace CP indexes for class and name+type of enclosing method
1.3469 + u2 old_class_idx = the_class->enclosing_method_class_index();
1.3470 + u2 old_method_idx = the_class->enclosing_method_method_index();
1.3471 + the_class->set_enclosing_method_indices(
1.3472 + scratch_class->enclosing_method_class_index(),
1.3473 + scratch_class->enclosing_method_method_index());
1.3474 + scratch_class->set_enclosing_method_indices(old_class_idx, old_method_idx);
1.3475 +
1.3476 + // keep track of previous versions of this class
1.3477 + the_class->add_previous_version(scratch_class, &emcp_methods,
1.3478 + emcp_method_count);
1.3479 +
1.3480 + RC_TIMER_STOP(_timer_rsc_phase1);
1.3481 + RC_TIMER_START(_timer_rsc_phase2);
1.3482 +
1.3483 + // Adjust constantpool caches and vtables for all classes
1.3484 + // that reference methods of the evolved class.
1.3485 + AdjustCpoolCacheAndVtable adjust_cpool_cache_and_vtable(THREAD);
1.3486 + ClassLoaderDataGraph::classes_do(&adjust_cpool_cache_and_vtable);
1.3487 +
1.3488 + // JSR-292 support
1.3489 + MemberNameTable* mnt = the_class->member_names();
1.3490 + if (mnt != NULL) {
1.3491 + bool trace_name_printed = false;
1.3492 + mnt->adjust_method_entries(_matching_old_methods,
1.3493 + _matching_new_methods,
1.3494 + _matching_methods_length,
1.3495 + &trace_name_printed);
1.3496 + }
1.3497 +
1.3498 + // Fix Resolution Error table also to remove old constant pools
1.3499 + SystemDictionary::delete_resolution_error(old_constants);
1.3500 +
1.3501 + if (the_class->oop_map_cache() != NULL) {
1.3502 + // Flush references to any obsolete methods from the oop map cache
1.3503 + // so that obsolete methods are not pinned.
1.3504 + the_class->oop_map_cache()->flush_obsolete_entries();
1.3505 + }
1.3506 +
1.3507 + // increment the classRedefinedCount field in the_class and in any
1.3508 + // direct and indirect subclasses of the_class
1.3509 + increment_class_counter((InstanceKlass *)the_class(), THREAD);
1.3510 +
1.3511 + // RC_TRACE macro has an embedded ResourceMark
1.3512 + RC_TRACE_WITH_THREAD(0x00000001, THREAD,
1.3513 + ("redefined name=%s, count=%d (avail_mem=" UINT64_FORMAT "K)",
1.3514 + the_class->external_name(),
1.3515 + java_lang_Class::classRedefinedCount(the_class_mirror),
1.3516 + os::available_memory() >> 10));
1.3517 +
1.3518 + RC_TIMER_STOP(_timer_rsc_phase2);
1.3519 +} // end redefine_single_class()
1.3520 +
1.3521 +
1.3522 +// Increment the classRedefinedCount field in the specific InstanceKlass
1.3523 +// and in all direct and indirect subclasses.
1.3524 +void VM_RedefineClasses::increment_class_counter(InstanceKlass *ik, TRAPS) {
1.3525 + oop class_mirror = ik->java_mirror();
1.3526 + Klass* class_oop = java_lang_Class::as_Klass(class_mirror);
1.3527 + int new_count = java_lang_Class::classRedefinedCount(class_mirror) + 1;
1.3528 + java_lang_Class::set_classRedefinedCount(class_mirror, new_count);
1.3529 +
1.3530 + if (class_oop != _the_class_oop) {
1.3531 + // _the_class_oop count is printed at end of redefine_single_class()
1.3532 + RC_TRACE_WITH_THREAD(0x00000008, THREAD,
1.3533 + ("updated count in subclass=%s to %d", ik->external_name(), new_count));
1.3534 + }
1.3535 +
1.3536 + for (Klass *subk = ik->subklass(); subk != NULL;
1.3537 + subk = subk->next_sibling()) {
1.3538 + if (subk->oop_is_instance()) {
1.3539 + // Only update instanceKlasses
1.3540 + InstanceKlass *subik = (InstanceKlass*)subk;
1.3541 + // recursively do subclasses of the current subclass
1.3542 + increment_class_counter(subik, THREAD);
1.3543 + }
1.3544 + }
1.3545 +}
1.3546 +
1.3547 +void VM_RedefineClasses::CheckClass::do_klass(Klass* k) {
1.3548 + bool no_old_methods = true; // be optimistic
1.3549 +
1.3550 + // Both array and instance classes have vtables.
1.3551 + // a vtable should never contain old or obsolete methods
1.3552 + ResourceMark rm(_thread);
1.3553 + if (k->vtable_length() > 0 &&
1.3554 + !k->vtable()->check_no_old_or_obsolete_entries()) {
1.3555 + if (RC_TRACE_ENABLED(0x00004000)) {
1.3556 + RC_TRACE_WITH_THREAD(0x00004000, _thread,
1.3557 + ("klassVtable::check_no_old_or_obsolete_entries failure"
1.3558 + " -- OLD or OBSOLETE method found -- class: %s",
1.3559 + k->signature_name()));
1.3560 + k->vtable()->dump_vtable();
1.3561 + }
1.3562 + no_old_methods = false;
1.3563 + }
1.3564 +
1.3565 + if (k->oop_is_instance()) {
1.3566 + HandleMark hm(_thread);
1.3567 + InstanceKlass *ik = InstanceKlass::cast(k);
1.3568 +
1.3569 + // an itable should never contain old or obsolete methods
1.3570 + if (ik->itable_length() > 0 &&
1.3571 + !ik->itable()->check_no_old_or_obsolete_entries()) {
1.3572 + if (RC_TRACE_ENABLED(0x00004000)) {
1.3573 + RC_TRACE_WITH_THREAD(0x00004000, _thread,
1.3574 + ("klassItable::check_no_old_or_obsolete_entries failure"
1.3575 + " -- OLD or OBSOLETE method found -- class: %s",
1.3576 + ik->signature_name()));
1.3577 + ik->itable()->dump_itable();
1.3578 + }
1.3579 + no_old_methods = false;
1.3580 + }
1.3581 +
1.3582 + // the constant pool cache should never contain old or obsolete methods
1.3583 + if (ik->constants() != NULL &&
1.3584 + ik->constants()->cache() != NULL &&
1.3585 + !ik->constants()->cache()->check_no_old_or_obsolete_entries()) {
1.3586 + if (RC_TRACE_ENABLED(0x00004000)) {
1.3587 + RC_TRACE_WITH_THREAD(0x00004000, _thread,
1.3588 + ("cp-cache::check_no_old_or_obsolete_entries failure"
1.3589 + " -- OLD or OBSOLETE method found -- class: %s",
1.3590 + ik->signature_name()));
1.3591 + ik->constants()->cache()->dump_cache();
1.3592 + }
1.3593 + no_old_methods = false;
1.3594 + }
1.3595 + }
1.3596 +
1.3597 + // print and fail guarantee if old methods are found.
1.3598 + if (!no_old_methods) {
1.3599 + if (RC_TRACE_ENABLED(0x00004000)) {
1.3600 + dump_methods();
1.3601 + } else {
1.3602 + tty->print_cr("INFO: use the '-XX:TraceRedefineClasses=16384' option "
1.3603 + "to see more info about the following guarantee() failure.");
1.3604 + }
1.3605 + guarantee(false, "OLD and/or OBSOLETE method(s) found");
1.3606 + }
1.3607 +}
1.3608 +
1.3609 +
1.3610 +void VM_RedefineClasses::dump_methods() {
1.3611 + int j;
1.3612 + RC_TRACE(0x00004000, ("_old_methods --"));
1.3613 + for (j = 0; j < _old_methods->length(); ++j) {
1.3614 + Method* m = _old_methods->at(j);
1.3615 + RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index()));
1.3616 + m->access_flags().print_on(tty);
1.3617 + tty->print(" -- ");
1.3618 + m->print_name(tty);
1.3619 + tty->cr();
1.3620 + }
1.3621 + RC_TRACE(0x00004000, ("_new_methods --"));
1.3622 + for (j = 0; j < _new_methods->length(); ++j) {
1.3623 + Method* m = _new_methods->at(j);
1.3624 + RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index()));
1.3625 + m->access_flags().print_on(tty);
1.3626 + tty->print(" -- ");
1.3627 + m->print_name(tty);
1.3628 + tty->cr();
1.3629 + }
1.3630 + RC_TRACE(0x00004000, ("_matching_(old/new)_methods --"));
1.3631 + for (j = 0; j < _matching_methods_length; ++j) {
1.3632 + Method* m = _matching_old_methods[j];
1.3633 + RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index()));
1.3634 + m->access_flags().print_on(tty);
1.3635 + tty->print(" -- ");
1.3636 + m->print_name(tty);
1.3637 + tty->cr();
1.3638 + m = _matching_new_methods[j];
1.3639 + RC_TRACE_NO_CR(0x00004000, (" (%5d) ", m->vtable_index()));
1.3640 + m->access_flags().print_on(tty);
1.3641 + tty->cr();
1.3642 + }
1.3643 + RC_TRACE(0x00004000, ("_deleted_methods --"));
1.3644 + for (j = 0; j < _deleted_methods_length; ++j) {
1.3645 + Method* m = _deleted_methods[j];
1.3646 + RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index()));
1.3647 + m->access_flags().print_on(tty);
1.3648 + tty->print(" -- ");
1.3649 + m->print_name(tty);
1.3650 + tty->cr();
1.3651 + }
1.3652 + RC_TRACE(0x00004000, ("_added_methods --"));
1.3653 + for (j = 0; j < _added_methods_length; ++j) {
1.3654 + Method* m = _added_methods[j];
1.3655 + RC_TRACE_NO_CR(0x00004000, ("%4d (%5d) ", j, m->vtable_index()));
1.3656 + m->access_flags().print_on(tty);
1.3657 + tty->print(" -- ");
1.3658 + m->print_name(tty);
1.3659 + tty->cr();
1.3660 + }
1.3661 +}
