8f039b5629
Co-authored-by: Frederic Parain <fparain@openjdk.org> Reviewed-by: iklam, fparain, dholmes
119 lines
5.2 KiB
C++
119 lines
5.2 KiB
C++
/*
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* Copyright (c) 2023, 2024, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*/
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#include "precompiled.hpp"
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#include "classfile/classLoaderData.hpp"
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#include "classfile/placeholders.hpp"
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#include "classfile/symbolTable.hpp"
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#include "oops/symbol.hpp"
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#include "runtime/interfaceSupport.inline.hpp"
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#include "runtime/mutexLocker.hpp"
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#include "threadHelper.inline.hpp"
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#include "unittest.hpp"
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// Test that multiple threads calling handle_parallel_super_load don't underflow supername refcount.
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TEST_VM(PlaceholderTable, supername) {
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JavaThread* THREAD = JavaThread::current();
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JavaThread* T2 = THREAD;
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// the thread should be in vm to use locks
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ThreadInVMfromNative tivfn(THREAD);
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// Assert messages assume these symbols are unique, and the refcounts start at one.
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Symbol* A = SymbolTable::new_symbol("abc2_8_2023_class");
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Symbol* D = SymbolTable::new_symbol("def2_8_2023_class");
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Symbol* super = SymbolTable::new_symbol("super2_8_2023_supername");
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Symbol* interf = SymbolTable::new_symbol("interface2_8_2023_supername");
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ClassLoaderData* loader_data = ClassLoaderData::the_null_class_loader_data();
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{
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MutexLocker ml(THREAD, SystemDictionary_lock);
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PlaceholderTable::classloadAction super_action = PlaceholderTable::DETECT_CIRCULARITY;
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PlaceholderTable::classloadAction define_action = PlaceholderTable::DEFINE_CLASS;
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// DefineClass A and D
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PlaceholderTable::find_and_add(A, loader_data, define_action, nullptr, THREAD);
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PlaceholderTable::find_and_add(D, loader_data, define_action, nullptr, T2);
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// Load interfaces first to get supername replaced
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PlaceholderTable::find_and_add(A, loader_data, super_action, interf, THREAD);
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PlaceholderTable::find_and_remove(A, loader_data, super_action, THREAD);
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PlaceholderTable::find_and_add(D, loader_data, super_action, interf, T2);
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PlaceholderTable::find_and_remove(D, loader_data, super_action, T2);
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ASSERT_EQ(interf->refcount(), 1) << "supername is replaced with null";
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// Add placeholder to the table for loading A and super, and D also loading super
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PlaceholderTable::find_and_add(A, loader_data, super_action, super, THREAD);
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PlaceholderTable::find_and_add(D, loader_data, super_action, super, T2);
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// Another thread comes in and finds A loading Super
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PlaceholderEntry* placeholder = PlaceholderTable::get_entry(A, loader_data);
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SymbolHandle supername = placeholder->next_klass_name();
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// Other thread is done before handle_parallel_super_load
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PlaceholderTable::find_and_remove(A, loader_data, super_action, THREAD);
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// if THREAD drops reference to supername (loading failed or class unloaded), we're left with
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// a supername without refcount
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super->decrement_refcount();
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// handle_parallel_super_load (same thread doesn't assert)
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PlaceholderTable::find_and_add(A, loader_data, super_action, supername, T2);
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// Refcount should be 3: one in table for class A, one in table for class D
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// and one locally with SymbolHandle keeping it alive
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placeholder = PlaceholderTable::get_entry(A, loader_data);
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supername = placeholder->next_klass_name();
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EXPECT_EQ(super->refcount(), 3) << "super class name refcount should be 3";
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// Second thread's done too
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PlaceholderTable::find_and_remove(D, loader_data, super_action, T2);
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// Other threads are done.
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PlaceholderTable::find_and_remove(A, loader_data, super_action, THREAD);
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// Remove A and D define_class placeholder
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PlaceholderTable::find_and_remove(A, loader_data, define_action, THREAD);
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PlaceholderTable::find_and_remove(D, loader_data, define_action, T2);
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placeholder = PlaceholderTable::get_entry(A, loader_data);
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ASSERT_TRUE(placeholder == nullptr) << "placeholder should be removed";
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placeholder = PlaceholderTable::get_entry(D, loader_data);
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ASSERT_TRUE(placeholder == nullptr) << "placeholder should be removed";
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EXPECT_EQ(super->refcount(), 1) << "super class name refcount should be 1 - kept alive in this scope";
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}
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EXPECT_EQ(A->refcount(), 1) << "first lass name refcount should be 1";
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EXPECT_EQ(D->refcount(), 1) << "second class name refcount should be 1";
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EXPECT_EQ(super->refcount(), 0) << "super class name refcount should be 0 - was unloaded.";
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// clean up temporary symbols
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A->decrement_refcount();
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D->decrement_refcount();
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interf->decrement_refcount();
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}
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