metadataOnStackMark.hpp

/*
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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
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 * 2 along with this work; if not, write to the Free Software Foundation,
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#ifndef SHARE_VM_CLASSFILE_METADATAONSTACKMARK_HPP
#define SHARE_VM_CLASSFILE_METADATAONSTACKMARK_HPP

#include "memory/allocation.hpp"
#include "utilities/chunkedList.hpp"

class Metadata;

typedef ChunkedList<Metadata*, mtInternal> MetadataOnStackBuffer;

// Helper class to mark and unmark metadata used on the stack as either handles
// or executing methods, so that it can't be deleted during class redefinition
// and class unloading.
// This is also used for other things that can be deallocated, like class
// metadata during parsing, relocated methods, and methods in backtraces.
class MetadataOnStackMark : public StackObj {
  NOT_PRODUCT(static bool _is_active;)

  static volatile MetadataOnStackBuffer* _used_buffers;
  static volatile MetadataOnStackBuffer* _free_buffers;

  static MetadataOnStackBuffer* allocate_buffer();
  static void retire_buffer(MetadataOnStackBuffer* buffer);

 public:
  MetadataOnStackMark(bool has_redefined_a_class);
   ~MetadataOnStackMark();

  static void record(Metadata* m, Thread* thread);
  static void retire_buffer_for_thread(Thread* thread);
  static bool has_buffer_for_thread(Thread* thread);
};

#endif // SHARE_VM_CLASSFILE_METADATAONSTACKMARK_HPP