1 /* 2 * Copyright (c) 2022, Red Hat, Inc. All rights reserved. 3 * Copyright Amazon.com Inc. or its affiliates. All Rights Reserved. 4 * Copyright (c) 2024, Oracle and/or its affiliates. All rights reserved. 5 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 6 * 7 * This code is free software; you can redistribute it and/or modify it 8 * under the terms of the GNU General Public License version 2 only, as 9 * published by the Free Software Foundation. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 * 25 */ 26 27 #ifndef SHARE_RUNTIME_LOCKSTACK_HPP 28 #define SHARE_RUNTIME_LOCKSTACK_HPP 29 30 #include "oops/oopsHierarchy.hpp" 31 #include "utilities/globalDefinitions.hpp" 32 #include "utilities/sizes.hpp" 33 34 class JavaThread; 35 class ObjectMonitor; 36 class OopClosure; 37 class outputStream; 38 template<typename> 39 class GrowableArray; 40 class Thread; 41 42 class LockStack { 43 friend class LockStackTest; 44 friend class VMStructs; 45 JVMCI_ONLY(friend class JVMCIVMStructs;) 46 public: 47 static const int CAPACITY = 8; 48 private: 49 50 // TODO: It would be very useful if JavaThread::lock_stack_offset() and friends were constexpr, 51 // but this is currently not the case because we're using offset_of() which is non-constexpr, 52 // GCC would warn about non-standard-layout types if we were using offsetof() (which *is* constexpr). 53 static const int lock_stack_offset; 54 static const int lock_stack_top_offset; 55 static const int lock_stack_base_offset; 56 57 // The offset of the next element, in bytes, relative to the JavaThread structure. 58 // We do this instead of a simple index into the array because this allows for 59 // efficient addressing in generated code. 60 uint32_t _top; 61 // The _bad_oop_sentinel acts as a sentinel value to elide underflow checks in generated code. 62 // The correct layout is statically asserted in the constructor. 63 const uintptr_t _bad_oop_sentinel = badOopVal; 64 oop _base[CAPACITY]; 65 66 // Get the owning thread of this lock-stack. 67 inline JavaThread* get_thread() const; 68 69 // Tests if the calling thread is the thread that owns this lock-stack. 70 bool is_owning_thread() const; 71 72 // Verifies consistency of the lock-stack. 73 void verify(const char* msg) const PRODUCT_RETURN; 74 75 // Given an offset (in bytes) calculate the index into the lock-stack. 76 static inline int to_index(uint32_t offset); 77 78 public: 79 static ByteSize top_offset() { return byte_offset_of(LockStack, _top); } 80 static ByteSize base_offset() { return byte_offset_of(LockStack, _base); } 81 82 LockStack(JavaThread* jt); 83 84 // The boundary indicies of the lock-stack. 85 static uint32_t start_offset(); 86 static uint32_t end_offset(); 87 88 // Returns true if the lock-stack is full. False otherwise. 89 inline bool is_full() const; 90 91 // Pushes an oop on this lock-stack. 92 inline void push(oop o); 93 94 // Get the oldest oop from this lock-stack. 95 // Precondition: This lock-stack must not be empty. 96 inline oop bottom() const; 97 98 // Is the lock-stack empty. 99 inline bool is_empty() const; 100 101 // Check if object is recursive. 102 // Precondition: This lock-stack must contain the oop. 103 inline bool is_recursive(oop o) const; 104 105 // Try recursive enter. 106 // Precondition: This lock-stack must not be full. 107 inline bool try_recursive_enter(oop o); 108 109 // Try recursive exit. 110 // Precondition: This lock-stack must contain the oop. 111 inline bool try_recursive_exit(oop o); 112 113 // Removes an oop from an arbitrary location of this lock-stack. 114 // Precondition: This lock-stack must contain the oop. 115 // Returns the number of oops removed. 116 inline size_t remove(oop o); 117 118 // Tests whether the oop is on this lock-stack. 119 inline bool contains(oop o) const; 120 121 inline int monitor_count() const; 122 inline void move_to_address(oop* start); 123 inline void move_from_address(oop* start, int count); 124 inline int unique_count() const NOT_DEBUG_RETURN0; 125 126 // GC support 127 inline void oops_do(OopClosure* cl); 128 129 // Printing 130 void print_on(outputStream* st); 131 }; 132 133 class OMCache { 134 friend class VMStructs; 135 public: 136 static constexpr int CAPACITY = 8; 137 138 private: 139 struct OMCacheEntry { 140 oop _oop = nullptr; 141 ObjectMonitor* _monitor = nullptr; 142 } _entries[CAPACITY]; 143 const oop _null_sentinel = nullptr; 144 145 public: 146 static ByteSize entries_offset() { return byte_offset_of(OMCache, _entries); } 147 static constexpr ByteSize oop_to_oop_difference() { return in_ByteSize(sizeof(OMCacheEntry)); } 148 static constexpr ByteSize oop_to_monitor_difference() { return in_ByteSize(sizeof(oop)); } 149 150 explicit OMCache(JavaThread* jt); 151 152 inline ObjectMonitor* get_monitor(oop o); 153 inline void set_monitor(ObjectMonitor* monitor); 154 inline void clear(); 155 156 }; 157 158 #endif // SHARE_RUNTIME_LOCKSTACK_HPP