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24 
25 #ifndef SHARE_CLASSFILE_METADATAONSTACKMARK_HPP
26 #define SHARE_CLASSFILE_METADATAONSTACKMARK_HPP
27 
28 #include "memory/allocation.hpp"
29 #include "utilities/chunkedList.hpp"
30 
31 class Metadata;
32 
33 typedef ChunkedList<Metadata*, mtInternal> MetadataOnStackBuffer;
34 
35 // Helper class to mark and unmark metadata used on the stack as either handles
36 // or executing methods, so that it can't be deleted during class redefinition
37 // and class unloading.
38 // This is also used for other things that can be deallocated, like class
39 // metadata during parsing if errors occur, relocated methods, and temporary
40 // constant pools.
41 class MetadataOnStackMark : public StackObj {
42   NOT_PRODUCT(static bool _is_active;)
43   static MetadataOnStackBuffer* _used_buffers;
44   static MetadataOnStackBuffer* _free_buffers;
45   static MetadataOnStackBuffer* _current_buffer;
46 
47   static MetadataOnStackBuffer* allocate_buffer();
48   static void retire_buffer(MetadataOnStackBuffer* buffer);
49 
50  public:
51   MetadataOnStackMark(bool walk_all_metadata, bool redefinition_walk);
52    ~MetadataOnStackMark();
53 
54   static void record(Metadata* m);
55   static void retire_current_buffer();
56 };
57 
58 #endif // SHARE_CLASSFILE_METADATAONSTACKMARK_HPP
59