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/*
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* Copyright 2003-2006 Sun Microsystems, Inc. All Rights Reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
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* CA 95054 USA or visit www.sun.com if you need additional information or
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* have any questions.
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*
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*/
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# include "incls/_precompiled.incl"
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# include "incls/_loaderConstraints.cpp.incl"
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LoaderConstraintTable::LoaderConstraintTable(int nof_buckets)
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: Hashtable(nof_buckets, sizeof(LoaderConstraintEntry)) {};
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LoaderConstraintEntry* LoaderConstraintTable::new_entry(
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unsigned int hash, symbolOop name,
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klassOop klass, int num_loaders,
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int max_loaders) {
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LoaderConstraintEntry* entry;
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entry = (LoaderConstraintEntry*)Hashtable::new_entry(hash, klass);
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entry->set_name(name);
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entry->set_num_loaders(num_loaders);
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entry->set_max_loaders(max_loaders);
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return entry;
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}
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void LoaderConstraintTable::oops_do(OopClosure* f) {
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for (int index = 0; index < table_size(); index++) {
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for (LoaderConstraintEntry* probe = bucket(index);
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probe != NULL;
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probe = probe->next()) {
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f->do_oop((oop*)(probe->name_addr()));
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if (probe->klass() != NULL) {
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f->do_oop((oop*)probe->klass_addr());
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}
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for (int n = 0; n < probe->num_loaders(); n++) {
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if (probe->loader(n) != NULL) {
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f->do_oop(probe->loader_addr(n));
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}
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}
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}
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}
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}
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// We must keep the symbolOop used in the name alive. We'll use the
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// loaders to decide if a particular entry can be purged.
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void LoaderConstraintTable::always_strong_classes_do(OopClosure* blk) {
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// We must keep the symbolOop used in the name alive.
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for (int cindex = 0; cindex < table_size(); cindex++) {
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for (LoaderConstraintEntry* lc_probe = bucket(cindex);
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lc_probe != NULL;
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lc_probe = lc_probe->next()) {
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assert (lc_probe->name() != NULL, "corrupted loader constraint table");
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blk->do_oop((oop*)lc_probe->name_addr());
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}
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}
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}
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// The loaderConstraintTable must always be accessed with the
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// SystemDictionary lock held. This is true even for readers as
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// entries in the table could be being dynamically resized.
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LoaderConstraintEntry** LoaderConstraintTable::find_loader_constraint(
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symbolHandle name, Handle loader) {
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unsigned int hash = compute_hash(name);
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int index = hash_to_index(hash);
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LoaderConstraintEntry** pp = bucket_addr(index);
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while (*pp) {
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LoaderConstraintEntry* p = *pp;
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if (p->hash() == hash) {
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if (p->name() == name()) {
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for (int i = p->num_loaders() - 1; i >= 0; i--) {
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if (p->loader(i) == loader()) {
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return pp;
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}
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}
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}
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}
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pp = p->next_addr();
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}
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return pp;
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}
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void LoaderConstraintTable::purge_loader_constraints(BoolObjectClosure* is_alive) {
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assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint")
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// Remove unloaded entries from constraint table
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for (int index = 0; index < table_size(); index++) {
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LoaderConstraintEntry** p = bucket_addr(index);
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while(*p) {
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LoaderConstraintEntry* probe = *p;
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klassOop klass = probe->klass();
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// Remove klass that is no longer alive
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if (klass != NULL && !is_alive->do_object_b(klass)) {
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probe->set_klass(NULL);
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if (TraceLoaderConstraints) {
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ResourceMark rm;
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tty->print_cr("[Purging class object from constraint for name %s,"
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" loader list:",
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probe->name()->as_C_string());
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for (int i = 0; i < probe->num_loaders(); i++) {
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tty->print_cr("[ [%d]: %s", i,
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SystemDictionary::loader_name(probe->loader(i)));
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}
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}
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}
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// Remove entries no longer alive from loader array
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int n = 0;
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while (n < probe->num_loaders()) {
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if (probe->loader(n) != NULL) {
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if (!is_alive->do_object_b(probe->loader(n))) {
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if (TraceLoaderConstraints) {
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ResourceMark rm;
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tty->print_cr("[Purging loader %s from constraint for name %s",
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SystemDictionary::loader_name(probe->loader(n)),
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probe->name()->as_C_string()
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);
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}
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// Compact array
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int num = probe->num_loaders() - 1;
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probe->set_num_loaders(num);
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probe->set_loader(n, probe->loader(num));
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probe->set_loader(num, NULL);
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if (TraceLoaderConstraints) {
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ResourceMark rm;
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tty->print_cr("[New loader list:");
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for (int i = 0; i < probe->num_loaders(); i++) {
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tty->print_cr("[ [%d]: %s", i,
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SystemDictionary::loader_name(probe->loader(i)));
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}
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}
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continue; // current element replaced, so restart without
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// incrementing n
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}
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}
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n++;
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}
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// Check whether entry should be purged
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if (probe->num_loaders() < 2) {
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if (TraceLoaderConstraints) {
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ResourceMark rm;
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tty->print("[Purging complete constraint for name %s\n",
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probe->name()->as_C_string());
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}
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// Purge entry
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*p = probe->next();
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FREE_C_HEAP_ARRAY(oop, probe->loaders());
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free_entry(probe);
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} else {
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#ifdef ASSERT
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assert(is_alive->do_object_b(probe->name()), "name should be live");
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if (probe->klass() != NULL) {
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assert(is_alive->do_object_b(probe->klass()), "klass should be live");
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}
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for (n = 0; n < probe->num_loaders(); n++) {
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if (probe->loader(n) != NULL) {
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assert(is_alive->do_object_b(probe->loader(n)), "loader should be live");
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}
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}
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#endif
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// Go to next entry
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p = probe->next_addr();
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}
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}
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}
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}
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bool LoaderConstraintTable::add_entry(symbolHandle class_name,
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klassOop klass1, Handle class_loader1,
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klassOop klass2, Handle class_loader2) {
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int failure_code = 0; // encode different reasons for failing
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if (klass1 != NULL && klass2 != NULL && klass1 != klass2) {
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failure_code = 1;
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} else {
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klassOop klass = klass1 != NULL ? klass1 : klass2;
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LoaderConstraintEntry** pp1 = find_loader_constraint(class_name,
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class_loader1);
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if (*pp1 != NULL && (*pp1)->klass() != NULL) {
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if (klass != NULL) {
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if (klass != (*pp1)->klass()) {
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failure_code = 2;
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}
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} else {
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klass = (*pp1)->klass();
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}
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}
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LoaderConstraintEntry** pp2 = find_loader_constraint(class_name,
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class_loader2);
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if (*pp2 != NULL && (*pp2)->klass() != NULL) {
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if (klass != NULL) {
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if (klass != (*pp2)->klass()) {
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failure_code = 3;
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}
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} else {
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klass = (*pp2)->klass();
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}
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}
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if (failure_code == 0) {
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if (*pp1 == NULL && *pp2 == NULL) {
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unsigned int hash = compute_hash(class_name);
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int index = hash_to_index(hash);
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LoaderConstraintEntry* p;
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p = new_entry(hash, class_name(), klass, 2, 2);
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p->set_loaders(NEW_C_HEAP_ARRAY(oop, 2));
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p->set_loader(0, class_loader1());
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p->set_loader(1, class_loader2());
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p->set_klass(klass);
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p->set_next(bucket(index));
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set_entry(index, p);
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if (TraceLoaderConstraints) {
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ResourceMark rm;
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tty->print("[Adding new constraint for name: %s, loader[0]: %s,"
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" loader[1]: %s ]\n",
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class_name()->as_C_string(),
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SystemDictionary::loader_name(class_loader1()),
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SystemDictionary::loader_name(class_loader2())
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);
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}
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} else if (*pp1 == *pp2) {
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/* constraint already imposed */
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if ((*pp1)->klass() == NULL) {
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(*pp1)->set_klass(klass);
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if (TraceLoaderConstraints) {
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ResourceMark rm;
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tty->print("[Setting class object in existing constraint for"
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" name: %s and loader %s ]\n",
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class_name()->as_C_string(),
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SystemDictionary::loader_name(class_loader1())
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);
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}
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} else {
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assert((*pp1)->klass() == klass, "loader constraints corrupted");
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}
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} else if (*pp1 == NULL) {
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extend_loader_constraint(*pp2, class_loader1, klass);
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} else if (*pp2 == NULL) {
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extend_loader_constraint(*pp1, class_loader2, klass);
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} else {
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merge_loader_constraints(pp1, pp2, klass);
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}
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}
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}
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if (failure_code != 0 && TraceLoaderConstraints) {
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ResourceMark rm;
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const char* reason = "";
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switch(failure_code) {
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case 1: reason = "the class objects presented by loader[0] and loader[1]"
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" are different"; break;
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case 2: reason = "the class object presented by loader[0] does not match"
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" the stored class object in the constraint"; break;
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case 3: reason = "the class object presented by loader[1] does not match"
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" the stored class object in the constraint"; break;
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default: reason = "unknown reason code";
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}
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tty->print("[Failed to add constraint for name: %s, loader[0]: %s,"
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" loader[1]: %s, Reason: %s ]\n",
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class_name()->as_C_string(),
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SystemDictionary::loader_name(class_loader1()),
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SystemDictionary::loader_name(class_loader2()),
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reason
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);
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}
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return failure_code == 0;
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}
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// return true if the constraint was updated, false if the constraint is
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// violated
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bool LoaderConstraintTable::check_or_update(instanceKlassHandle k,
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Handle loader,
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symbolHandle name) {
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LoaderConstraintEntry* p = *(find_loader_constraint(name, loader));
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if (p && p->klass() != NULL && p->klass() != k()) {
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if (TraceLoaderConstraints) {
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ResourceMark rm;
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tty->print("[Constraint check failed for name %s, loader %s: "
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"the presented class object differs from that stored ]\n",
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name()->as_C_string(),
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SystemDictionary::loader_name(loader()));
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}
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return false;
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} else {
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if (p && p->klass() == NULL) {
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p->set_klass(k());
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if (TraceLoaderConstraints) {
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ResourceMark rm;
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tty->print("[Updating constraint for name %s, loader %s, "
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"by setting class object ]\n",
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name()->as_C_string(),
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SystemDictionary::loader_name(loader()));
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}
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}
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return true;
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}
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}
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klassOop LoaderConstraintTable::find_constrained_klass(symbolHandle name,
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Handle loader) {
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LoaderConstraintEntry *p = *(find_loader_constraint(name, loader));
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if (p != NULL && p->klass() != NULL)
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return p->klass();
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// No constraints, or else no klass loaded yet.
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return NULL;
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}
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void LoaderConstraintTable::ensure_loader_constraint_capacity(
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LoaderConstraintEntry *p,
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int nfree) {
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if (p->max_loaders() - p->num_loaders() < nfree) {
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int n = nfree + p->num_loaders();
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oop* new_loaders = NEW_C_HEAP_ARRAY(oop, n);
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memcpy(new_loaders, p->loaders(), sizeof(oop) * p->num_loaders());
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p->set_max_loaders(n);
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FREE_C_HEAP_ARRAY(oop, p->loaders());
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p->set_loaders(new_loaders);
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}
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}
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void LoaderConstraintTable::extend_loader_constraint(LoaderConstraintEntry* p,
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Handle loader,
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klassOop klass) {
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ensure_loader_constraint_capacity(p, 1);
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int num = p->num_loaders();
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p->set_loader(num, loader());
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p->set_num_loaders(num + 1);
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if (TraceLoaderConstraints) {
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ResourceMark rm;
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tty->print("[Extending constraint for name %s by adding loader[%d]: %s %s",
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p->name()->as_C_string(),
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num,
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SystemDictionary::loader_name(loader()),
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(p->klass() == NULL ? " and setting class object ]\n" : " ]\n")
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);
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}
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if (p->klass() == NULL) {
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p->set_klass(klass);
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} else {
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assert(klass == NULL || p->klass() == klass, "constraints corrupted");
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}
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}
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void LoaderConstraintTable::merge_loader_constraints(
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LoaderConstraintEntry** pp1,
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LoaderConstraintEntry** pp2,
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klassOop klass) {
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// make sure *pp1 has higher capacity
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if ((*pp1)->max_loaders() < (*pp2)->max_loaders()) {
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LoaderConstraintEntry** tmp = pp2;
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pp2 = pp1;
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pp1 = tmp;
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}
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LoaderConstraintEntry* p1 = *pp1;
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LoaderConstraintEntry* p2 = *pp2;
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ensure_loader_constraint_capacity(p1, p2->num_loaders());
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for (int i = 0; i < p2->num_loaders(); i++) {
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int num = p1->num_loaders();
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p1->set_loader(num, p2->loader(i));
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p1->set_num_loaders(num + 1);
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}
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if (TraceLoaderConstraints) {
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ResourceMark rm;
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tty->print_cr("[Merged constraints for name %s, new loader list:",
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p1->name()->as_C_string()
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);
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403 |
for (int i = 0; i < p1->num_loaders(); i++) {
|
|
404 |
tty->print_cr("[ [%d]: %s", i,
|
|
405 |
SystemDictionary::loader_name(p1->loader(i)));
|
|
406 |
}
|
|
407 |
if (p1->klass() == NULL) {
|
|
408 |
tty->print_cr("[... and setting class object]");
|
|
409 |
}
|
|
410 |
}
|
|
411 |
|
|
412 |
// p1->klass() will hold NULL if klass, p2->klass(), and old
|
|
413 |
// p1->klass() are all NULL. In addition, all three must have
|
|
414 |
// matching non-NULL values, otherwise either the constraints would
|
|
415 |
// have been violated, or the constraints had been corrupted (and an
|
|
416 |
// assertion would fail).
|
|
417 |
if (p2->klass() != NULL) {
|
|
418 |
assert(p2->klass() == klass, "constraints corrupted");
|
|
419 |
}
|
|
420 |
if (p1->klass() == NULL) {
|
|
421 |
p1->set_klass(klass);
|
|
422 |
} else {
|
|
423 |
assert(p1->klass() == klass, "constraints corrupted");
|
|
424 |
}
|
|
425 |
|
|
426 |
*pp2 = p2->next();
|
|
427 |
FREE_C_HEAP_ARRAY(oop, p2->loaders());
|
|
428 |
free_entry(p2);
|
|
429 |
return;
|
|
430 |
}
|
|
431 |
|
|
432 |
|
|
433 |
void LoaderConstraintTable::verify(Dictionary* dictionary) {
|
|
434 |
Thread *thread = Thread::current();
|
|
435 |
for (int cindex = 0; cindex < _loader_constraint_size; cindex++) {
|
|
436 |
for (LoaderConstraintEntry* probe = bucket(cindex);
|
|
437 |
probe != NULL;
|
|
438 |
probe = probe->next()) {
|
|
439 |
guarantee(probe->name()->is_symbol(), "should be symbol");
|
|
440 |
if (probe->klass() != NULL) {
|
|
441 |
instanceKlass* ik = instanceKlass::cast(probe->klass());
|
|
442 |
guarantee(ik->name() == probe->name(), "name should match");
|
|
443 |
symbolHandle name (thread, ik->name());
|
|
444 |
Handle loader(thread, ik->class_loader());
|
|
445 |
unsigned int d_hash = dictionary->compute_hash(name, loader);
|
|
446 |
int d_index = dictionary->hash_to_index(d_hash);
|
|
447 |
klassOop k = dictionary->find_class(d_index, d_hash, name, loader);
|
|
448 |
guarantee(k == probe->klass(), "klass should be in dictionary");
|
|
449 |
}
|
|
450 |
for (int n = 0; n< probe->num_loaders(); n++) {
|
|
451 |
guarantee(probe->loader(n)->is_oop_or_null(), "should be oop");
|
|
452 |
}
|
|
453 |
}
|
|
454 |
}
|
|
455 |
}
|
|
456 |
|
|
457 |
#ifndef PRODUCT
|
|
458 |
|
|
459 |
// Called with the system dictionary lock held
|
|
460 |
void LoaderConstraintTable::print() {
|
|
461 |
ResourceMark rm;
|
|
462 |
|
|
463 |
assert_locked_or_safepoint(SystemDictionary_lock);
|
|
464 |
tty->print_cr("Java loader constraints (entries=%d)", _loader_constraint_size);
|
|
465 |
for (int cindex = 0; cindex < _loader_constraint_size; cindex++) {
|
|
466 |
for (LoaderConstraintEntry* probe = bucket(cindex);
|
|
467 |
probe != NULL;
|
|
468 |
probe = probe->next()) {
|
|
469 |
tty->print("%4d: ", cindex);
|
|
470 |
probe->name()->print();
|
|
471 |
tty->print(" , loaders:");
|
|
472 |
for (int n = 0; n < probe->num_loaders(); n++) {
|
|
473 |
probe->loader(n)->print_value();
|
|
474 |
tty->print(", ");
|
|
475 |
}
|
|
476 |
tty->cr();
|
|
477 |
}
|
|
478 |
}
|
|
479 |
}
|
|
480 |
#endif
|