src/hotspot/share/oops/oop.hpp

@@ -26,10 +26,11 @@
  #define SHARE_OOPS_OOP_HPP
  
  #include "memory/iterator.hpp"
  #include "memory/memRegion.hpp"
  #include "oops/accessDecorators.hpp"
+ #include "oops/compressedKlass.hpp"
  #include "oops/markWord.hpp"
  #include "oops/metadata.hpp"
  #include "runtime/atomic.hpp"
  #include "utilities/globalDefinitions.hpp"
  #include "utilities/macros.hpp"

@@ -52,14 +53,13 @@
  class oopDesc {
    friend class VMStructs;
    friend class JVMCIVMStructs;
   private:
    volatile markWord _mark;
-   union _metadata {
-     Klass*      _klass;
-     narrowKlass _compressed_klass;
-   } _metadata;
+ #ifndef _LP64
+   Klass*            _klass;
+ #endif
  
    // There may be ordering constraints on the initialization of fields that
    // make use of the C++ copy/assign incorrect.
    NONCOPYABLE(oopDesc);
  

@@ -73,10 +73,11 @@
  
    inline void set_mark(markWord m);
    static inline void set_mark(HeapWord* mem, markWord m);
  
    inline void release_set_mark(markWord m);
+   static inline void release_set_mark(HeapWord* mem, markWord m);
    inline markWord cas_set_mark(markWord new_mark, markWord old_mark);
    inline markWord cas_set_mark(markWord new_mark, markWord old_mark, atomic_memory_order order);
  
    // Used only to re-initialize the mark word (e.g., of promoted
    // objects during a GC) -- requires a valid klass pointer

@@ -84,16 +85,14 @@
  
    inline Klass* klass() const;
    inline Klass* klass_or_null() const;
    inline Klass* klass_or_null_acquire() const;
  
-   void set_narrow_klass(narrowKlass nk) NOT_CDS_JAVA_HEAP_RETURN;
+ #ifndef _LP64
    inline void set_klass(Klass* k);
    static inline void release_set_klass(HeapWord* mem, Klass* k);
- 
-   // For klass field compression
-   static inline void set_klass_gap(HeapWord* mem, int z);
+ #endif
  
    // size of object header, aligned to platform wordSize
    static constexpr int header_size() { return sizeof(oopDesc)/HeapWordSize; }
  
    // Returns whether this is an instance of k or an instance of a subclass of k

@@ -252,18 +251,21 @@
    inline bool is_forwarded() const;
  
    void verify_forwardee(oop forwardee) NOT_DEBUG_RETURN;
  
    inline void forward_to(oop p);
+   inline void forward_to_self();
  
    // Like "forward_to", but inserts the forwarding pointer atomically.
    // Exactly one thread succeeds in inserting the forwarding pointer, and
    // this call returns "NULL" for that thread; any other thread has the
    // value of the forwarding pointer returned and does not modify "this".
    inline oop forward_to_atomic(oop p, markWord compare, atomic_memory_order order = memory_order_conservative);
+   inline oop forward_to_self_atomic(markWord compare, atomic_memory_order order = memory_order_conservative);
  
    inline oop forwardee() const;
+   inline oop forwardee(markWord header) const;
  
    // Age of object during scavenge
    inline uint age() const;
    inline void incr_age();
  

@@ -298,24 +300,30 @@
  
    // Checks if the mark word needs to be preserved
    inline bool mark_must_be_preserved() const;
    inline bool mark_must_be_preserved(markWord m) const;
  
-   static bool has_klass_gap();
- 
    // for code generation
    static int mark_offset_in_bytes()      { return offset_of(oopDesc, _mark); }
-   static int klass_offset_in_bytes()     { return offset_of(oopDesc, _metadata._klass); }
-   static int klass_gap_offset_in_bytes() {
-     assert(has_klass_gap(), "only applicable to compressed klass pointers");
-     return klass_offset_in_bytes() + sizeof(narrowKlass);
+   static int klass_offset_in_bytes()     {
+ #ifdef _LP64
+     STATIC_ASSERT(markWord::klass_shift % 8 == 0);
+     return mark_offset_in_bytes() + markWord::klass_shift / 8;
+ #else
+     return offset_of(oopDesc, _klass);
+ #endif
    }
  
    // for error reporting
    static void* load_klass_raw(oop obj);
    static void* load_oop_raw(oop obj, int offset);
  
+   // Runtime entry
+ #ifdef _LP64
+   static narrowKlass load_nklass_runtime(oopDesc* o);
+ #endif
+ 
    DEBUG_ONLY(bool size_might_change();)
  };
  
  // An oopDesc is not initialized via a constructor.  Space is allocated in
  // the Java heap, and static functions provided here on HeapWord* are used