32 #include "unittest.hpp"
33
34 // Test that multiple threads calling handle_parallel_super_load don't underflow supername refcount.
35 TEST_VM(PlaceholderTable, supername) {
36 JavaThread* THREAD = JavaThread::current();
37 JavaThread* T2 = THREAD;
38 // the thread should be in vm to use locks
39 ThreadInVMfromNative tivfn(THREAD);
40
41 // Assert messages assume these symbols are unique, and the refcounts start at one.
42 Symbol* A = SymbolTable::new_symbol("abc2_8_2023_class");
43 Symbol* D = SymbolTable::new_symbol("def2_8_2023_class");
44 Symbol* super = SymbolTable::new_symbol("super2_8_2023_supername");
45 Symbol* interf = SymbolTable::new_symbol("interface2_8_2023_supername");
46
47 ClassLoaderData* loader_data = ClassLoaderData::the_null_class_loader_data();
48
49 {
50 MutexLocker ml(THREAD, SystemDictionary_lock);
51
52 PlaceholderTable::classloadAction super_action = PlaceholderTable::LOAD_SUPER;
53 PlaceholderTable::classloadAction define_action = PlaceholderTable::DEFINE_CLASS;
54
55 // DefineClass A and D
56 PlaceholderTable::find_and_add(A, loader_data, define_action, nullptr, THREAD);
57 PlaceholderTable::find_and_add(D, loader_data, define_action, nullptr, T2);
58
59 // Load interfaces first to get supername replaced
60 PlaceholderTable::find_and_add(A, loader_data, super_action, interf, THREAD);
61 PlaceholderTable::find_and_remove(A, loader_data, super_action, THREAD);
62
63 PlaceholderTable::find_and_add(D, loader_data, super_action, interf, T2);
64 PlaceholderTable::find_and_remove(D, loader_data, super_action, T2);
65
66 ASSERT_EQ(interf->refcount(), 1) << "supername is replaced with null";
67
68 // Add placeholder to the table for loading A and super, and D also loading super
69 PlaceholderTable::find_and_add(A, loader_data, super_action, super, THREAD);
70 PlaceholderTable::find_and_add(D, loader_data, super_action, super, T2);
71
72 // Another thread comes in and finds A loading Super
73 PlaceholderEntry* placeholder = PlaceholderTable::get_entry(A, loader_data);
74 SymbolHandle supername = placeholder->supername();
75
76 // Other thread is done before handle_parallel_super_load
77 PlaceholderTable::find_and_remove(A, loader_data, super_action, THREAD);
78
79 // if THREAD drops reference to supername (loading failed or class unloaded), we're left with
80 // a supername without refcount
81 super->decrement_refcount();
82
83 // handle_parallel_super_load (same thread doesn't assert)
84 PlaceholderTable::find_and_add(A, loader_data, super_action, supername, T2);
85
86 // Refcount should be 3: one in table for class A, one in table for class D
87 // and one locally with SymbolHandle keeping it alive
88 placeholder = PlaceholderTable::get_entry(A, loader_data);
89 supername = placeholder->supername();
90 EXPECT_EQ(super->refcount(), 3) << "super class name refcount should be 3";
91
92 // Second thread's done too
93 PlaceholderTable::find_and_remove(D, loader_data, super_action, T2);
94
95 // Other threads are done.
96 PlaceholderTable::find_and_remove(A, loader_data, super_action, THREAD);
97
98 // Remove A and D define_class placeholder
99 PlaceholderTable::find_and_remove(A, loader_data, define_action, THREAD);
100 PlaceholderTable::find_and_remove(D, loader_data, define_action, T2);
101
102 placeholder = PlaceholderTable::get_entry(A, loader_data);
103 ASSERT_TRUE(placeholder == nullptr) << "placeholder should be removed";
104 placeholder = PlaceholderTable::get_entry(D, loader_data);
105 ASSERT_TRUE(placeholder == nullptr) << "placeholder should be removed";
106
107 EXPECT_EQ(super->refcount(), 1) << "super class name refcount should be 1 - kept alive in this scope";
108 }
109
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32 #include "unittest.hpp"
33
34 // Test that multiple threads calling handle_parallel_super_load don't underflow supername refcount.
35 TEST_VM(PlaceholderTable, supername) {
36 JavaThread* THREAD = JavaThread::current();
37 JavaThread* T2 = THREAD;
38 // the thread should be in vm to use locks
39 ThreadInVMfromNative tivfn(THREAD);
40
41 // Assert messages assume these symbols are unique, and the refcounts start at one.
42 Symbol* A = SymbolTable::new_symbol("abc2_8_2023_class");
43 Symbol* D = SymbolTable::new_symbol("def2_8_2023_class");
44 Symbol* super = SymbolTable::new_symbol("super2_8_2023_supername");
45 Symbol* interf = SymbolTable::new_symbol("interface2_8_2023_supername");
46
47 ClassLoaderData* loader_data = ClassLoaderData::the_null_class_loader_data();
48
49 {
50 MutexLocker ml(THREAD, SystemDictionary_lock);
51
52 PlaceholderTable::classloadAction super_action = PlaceholderTable::DETECT_CIRCULARITY;
53 PlaceholderTable::classloadAction define_action = PlaceholderTable::DEFINE_CLASS;
54
55 // DefineClass A and D
56 PlaceholderTable::find_and_add(A, loader_data, define_action, nullptr, THREAD);
57 PlaceholderTable::find_and_add(D, loader_data, define_action, nullptr, T2);
58
59 // Load interfaces first to get supername replaced
60 PlaceholderTable::find_and_add(A, loader_data, super_action, interf, THREAD);
61 PlaceholderTable::find_and_remove(A, loader_data, super_action, THREAD);
62
63 PlaceholderTable::find_and_add(D, loader_data, super_action, interf, T2);
64 PlaceholderTable::find_and_remove(D, loader_data, super_action, T2);
65
66 ASSERT_EQ(interf->refcount(), 1) << "supername is replaced with null";
67
68 // Add placeholder to the table for loading A and super, and D also loading super
69 PlaceholderTable::find_and_add(A, loader_data, super_action, super, THREAD);
70 PlaceholderTable::find_and_add(D, loader_data, super_action, super, T2);
71
72 // Another thread comes in and finds A loading Super
73 PlaceholderEntry* placeholder = PlaceholderTable::get_entry(A, loader_data);
74 SymbolHandle supername = placeholder->next_klass_name();
75
76 // Other thread is done before handle_parallel_super_load
77 PlaceholderTable::find_and_remove(A, loader_data, super_action, THREAD);
78
79 // if THREAD drops reference to supername (loading failed or class unloaded), we're left with
80 // a supername without refcount
81 super->decrement_refcount();
82
83 // handle_parallel_super_load (same thread doesn't assert)
84 PlaceholderTable::find_and_add(A, loader_data, super_action, supername, T2);
85
86 // Refcount should be 3: one in table for class A, one in table for class D
87 // and one locally with SymbolHandle keeping it alive
88 placeholder = PlaceholderTable::get_entry(A, loader_data);
89 supername = placeholder->next_klass_name();
90 EXPECT_EQ(super->refcount(), 3) << "super class name refcount should be 3";
91
92 // Second thread's done too
93 PlaceholderTable::find_and_remove(D, loader_data, super_action, T2);
94
95 // Other threads are done.
96 PlaceholderTable::find_and_remove(A, loader_data, super_action, THREAD);
97
98 // Remove A and D define_class placeholder
99 PlaceholderTable::find_and_remove(A, loader_data, define_action, THREAD);
100 PlaceholderTable::find_and_remove(D, loader_data, define_action, T2);
101
102 placeholder = PlaceholderTable::get_entry(A, loader_data);
103 ASSERT_TRUE(placeholder == nullptr) << "placeholder should be removed";
104 placeholder = PlaceholderTable::get_entry(D, loader_data);
105 ASSERT_TRUE(placeholder == nullptr) << "placeholder should be removed";
106
107 EXPECT_EQ(super->refcount(), 1) << "super class name refcount should be 1 - kept alive in this scope";
108 }
109
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