src/hotspot/share/runtime/lockStack.cpp

@@ -1,8 +1,9 @@
  /*
   * Copyright (c) 2022, Red Hat, Inc. All rights reserved.
   * Copyright Amazon.com Inc. or its affiliates. All Rights Reserved.
+  * Copyright (c) 2024, Oracle and/or its affiliates. All rights reserved.
   * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   *
   * This code is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 only, as
   * published by the Free Software Foundation.

@@ -23,24 +24,38 @@
   *
   */
  
  #include "precompiled.hpp"
  #include "memory/allocation.hpp"
+ #include "oops/markWord.hpp"
+ #include "oops/oop.inline.hpp"
+ #include "runtime/globals.hpp"
  #include "runtime/lockStack.inline.hpp"
+ #include "runtime/objectMonitor.inline.hpp"
  #include "runtime/safepoint.hpp"
  #include "runtime/stackWatermark.hpp"
  #include "runtime/stackWatermarkSet.inline.hpp"
  #include "runtime/thread.hpp"
  #include "utilities/copy.hpp"
+ #include "utilities/debug.hpp"
+ #include "utilities/globalDefinitions.hpp"
+ #include "utilities/growableArray.hpp"
  #include "utilities/ostream.hpp"
  
+ #include <type_traits>
+ 
  const int LockStack::lock_stack_offset =      in_bytes(JavaThread::lock_stack_offset());
  const int LockStack::lock_stack_top_offset =  in_bytes(JavaThread::lock_stack_top_offset());
  const int LockStack::lock_stack_base_offset = in_bytes(JavaThread::lock_stack_base_offset());
  
  LockStack::LockStack(JavaThread* jt) :
    _top(lock_stack_base_offset), _base() {
+   // Make sure the layout of the object is compatible with the emitted code's assumptions.
+   STATIC_ASSERT(sizeof(_bad_oop_sentinel) == oopSize);
+   STATIC_ASSERT(sizeof(_base[0]) == oopSize);
+   STATIC_ASSERT(std::is_standard_layout<LockStack>::value);
+   STATIC_ASSERT(offsetof(LockStack, _bad_oop_sentinel) == offsetof(LockStack, _base) - oopSize);
  #ifdef ASSERT
    for (int i = 0; i < CAPACITY; i++) {
      _base[i] = nullptr;
    }
  #endif

@@ -60,15 +75,25 @@
  
  #ifndef PRODUCT
  void LockStack::verify(const char* msg) const {
    assert(LockingMode == LM_LIGHTWEIGHT, "never use lock-stack when light weight locking is disabled");
    assert((_top <= end_offset()), "lockstack overflow: _top %d end_offset %d", _top, end_offset());
-   assert((_top >= start_offset()), "lockstack underflow: _top %d end_offset %d", _top, start_offset());
+   assert((_top >= start_offset()), "lockstack underflow: _top %d start_offset %d", _top, start_offset());
    if (SafepointSynchronize::is_at_safepoint() || (Thread::current()->is_Java_thread() && is_owning_thread())) {
      int top = to_index(_top);
      for (int i = 0; i < top; i++) {
        assert(_base[i] != nullptr, "no zapped before top");
+       if (VM_Version::supports_recursive_lightweight_locking()) {
+         oop o = _base[i];
+         for (; i < top - 1; i++) {
+           // Consecutive entries may be the same
+           if (_base[i + 1] != o) {
+             break;
+           }
+         }
+       }
+ 
        for (int j = i + 1; j < top; j++) {
          assert(_base[i] != _base[j], "entries must be unique: %s", msg);
        }
      }
      for (int i = top; i < CAPACITY; i++) {

@@ -76,10 +101,64 @@
      }
    }
  }
  #endif
  
+ #ifdef ASSERT
+ void LockStack::verify_consistent_lock_order(GrowableArray<oop>& lock_order, bool leaf_frame) const {
+   int top_index = to_index(_top);
+   int lock_index = lock_order.length();
+ 
+   if (!leaf_frame) {
+     // If the lock_order is not from the leaf frame we must search
+     // for the top_index which fits with the most recent fast_locked
+     // objects in the lock stack.
+     while (lock_index-- > 0) {
+       const oop obj = lock_order.at(lock_index);
+       if (contains(obj)) {
+         for (int index = 0; index < top_index; index++) {
+           if (_base[index] == obj) {
+             // Found top index
+             top_index = index + 1;
+             break;
+           }
+         }
+ 
+         if (VM_Version::supports_recursive_lightweight_locking()) {
+           // With recursive looks there may be more of the same object
+           while (lock_index-- > 0 && lock_order.at(lock_index) == obj) {
+             top_index++;
+           }
+           assert(top_index <= to_index(_top), "too many obj in lock_order");
+         }
+ 
+         break;
+       }
+     }
+ 
+     lock_index = lock_order.length();
+   }
+ 
+   while (lock_index-- > 0) {
+     const oop obj = lock_order.at(lock_index);
+     const markWord mark = obj->mark_acquire();
+     assert(obj->is_locked(), "must be locked");
+     if (top_index > 0 && obj == _base[top_index - 1]) {
+       assert(mark.is_fast_locked() || mark.monitor()->is_owner_anonymous(),
+              "must be fast_locked or inflated by other thread");
+       top_index--;
+     } else {
+       assert(!mark.is_fast_locked(), "must be inflated");
+       assert(mark.monitor()->owner_raw() == get_thread() ||
+              (!leaf_frame && get_thread()->current_waiting_monitor() == mark.monitor()),
+              "must be owned by (or waited on by) thread");
+       assert(!contains(obj), "must not be on lock_stack");
+     }
+   }
+ }
+ #endif
+ 
  void LockStack::print_on(outputStream* st) {
    for (int i = to_index(_top); (--i) >= 0;) {
      st->print("LockStack[%d]: ", i);
      oop o = _base[i];
      if (oopDesc::is_oop(o)) {