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src/hotspot/share/oops/oop.inline.hpp

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*** 32,14 ***
  #include "oops/access.inline.hpp"
  #include "oops/arrayKlass.hpp"
  #include "oops/arrayOop.hpp"
  #include "oops/compressedKlass.inline.hpp"
  #include "oops/instanceKlass.hpp"
! #include "oops/markWord.hpp"
  #include "oops/oopsHierarchy.hpp"
  #include "runtime/atomic.hpp"
  #include "runtime/globals.hpp"
  #include "utilities/align.hpp"
  #include "utilities/debug.hpp"
  #include "utilities/macros.hpp"
  #include "utilities/globalDefinitions.hpp"
  
--- 32,17 ---
  #include "oops/access.inline.hpp"
  #include "oops/arrayKlass.hpp"
  #include "oops/arrayOop.hpp"
  #include "oops/compressedKlass.inline.hpp"
  #include "oops/instanceKlass.hpp"
! #include "oops/markWord.inline.hpp"
  #include "oops/oopsHierarchy.hpp"
  #include "runtime/atomic.hpp"
  #include "runtime/globals.hpp"
+ #include "runtime/objectMonitor.inline.hpp"
+ #include "runtime/safepoint.hpp"
+ #include "runtime/synchronizer.hpp"
  #include "utilities/align.hpp"
  #include "utilities/debug.hpp"
  #include "utilities/macros.hpp"
  #include "utilities/globalDefinitions.hpp"
  

*** 80,68 ***
  
  markWord oopDesc::cas_set_mark(markWord new_mark, markWord old_mark, atomic_memory_order order) {
    return Atomic::cmpxchg(&_mark, old_mark, new_mark, order);
  }
  
  void oopDesc::init_mark() {
    set_mark(markWord::prototype());
  }
  
  Klass* oopDesc::klass() const {
!   if (UseCompressedClassPointers) {
      return CompressedKlassPointers::decode_not_null(_metadata._compressed_klass);
!   } else {
!     return _metadata._klass;
!   }
  }
  
  Klass* oopDesc::klass_or_null() const {
!   if (UseCompressedClassPointers) {
      return CompressedKlassPointers::decode(_metadata._compressed_klass);
!   } else {
!     return _metadata._klass;
!   }
  }
  
  Klass* oopDesc::klass_or_null_acquire() const {
!   if (UseCompressedClassPointers) {
!     narrowKlass nklass = Atomic::load_acquire(&_metadata._compressed_klass);
!     return CompressedKlassPointers::decode(nklass);
!   } else {
!     return Atomic::load_acquire(&_metadata._klass);
!   }
  }
  
  Klass* oopDesc::klass_raw() const {
!   if (UseCompressedClassPointers) {
-     return CompressedKlassPointers::decode_raw(_metadata._compressed_klass);
-   } else {
-     return _metadata._klass;
-   }
  }
  
  void oopDesc::set_klass(Klass* k) {
!   assert(Universe::is_bootstrapping() || (k != nullptr && k->is_klass()), "incorrect Klass");
    if (UseCompressedClassPointers) {
      _metadata._compressed_klass = CompressedKlassPointers::encode_not_null(k);
    } else {
      _metadata._klass = k;
    }
  }
  
  void oopDesc::release_set_klass(HeapWord* mem, Klass* k) {
!   assert(Universe::is_bootstrapping() || (k != nullptr && k->is_klass()), "incorrect Klass");
    char* raw_mem = ((char*)mem + klass_offset_in_bytes());
    if (UseCompressedClassPointers) {
      Atomic::release_store((narrowKlass*)raw_mem,
                            CompressedKlassPointers::encode_not_null(k));
    } else {
      Atomic::release_store((Klass**)raw_mem, k);
    }
  }
  
  void oopDesc::set_klass_gap(HeapWord* mem, int v) {
    if (UseCompressedClassPointers) {
      *(int*)(((char*)mem) + klass_gap_offset_in_bytes()) = v;
    }
  }
  
--- 83,102 ---
  
  markWord oopDesc::cas_set_mark(markWord new_mark, markWord old_mark, atomic_memory_order order) {
    return Atomic::cmpxchg(&_mark, old_mark, new_mark, order);
  }
  
+ markWord oopDesc::resolve_mark() const {
+   assert(LockingMode != LM_LEGACY, "Not safe with legacy stack-locking");
+   markWord hdr = mark();
+   if (hdr.has_monitor()) {
+     ObjectMonitor* monitor = hdr.monitor();
+     return monitor->header();
+   }
+   return hdr;
+ }
+ 
  void oopDesc::init_mark() {
+ #ifdef _LP64
+   if (UseCompactObjectHeaders) {
+     markWord header = resolve_mark();
+     assert(UseCompressedClassPointers, "expect compressed klass pointers");
+     set_mark(markWord((header.value() & markWord::klass_mask_in_place) | markWord::prototype().value()));
+   } else
+ #endif
    set_mark(markWord::prototype());
  }
  
  Klass* oopDesc::klass() const {
! #ifdef _LP64
+   if (UseCompactObjectHeaders) {
+     assert(UseCompressedClassPointers, "only with compressed class pointers");
+     markWord header = resolve_mark();
+     return header.klass();
+   } else if (UseCompressedClassPointers) {
      return CompressedKlassPointers::decode_not_null(_metadata._compressed_klass);
!   } else
! #endif
!   return _metadata._klass;
  }
  
  Klass* oopDesc::klass_or_null() const {
! #ifdef _LP64
+   if (UseCompactObjectHeaders) {
+     assert(UseCompressedClassPointers, "only with compressed class pointers");
+     markWord header = resolve_mark();
+     return header.klass_or_null();
+   } else if (UseCompressedClassPointers) {
      return CompressedKlassPointers::decode(_metadata._compressed_klass);
!   } else
! #endif
!   return _metadata._klass;
  }
  
  Klass* oopDesc::klass_or_null_acquire() const {
! #ifdef _LP64
!   if (UseCompactObjectHeaders) {
!     assert(UseCompressedClassPointers, "only with compressed class pointers");
!     markWord header = mark_acquire();
!     if (header.has_monitor()) {
!       header = header.monitor()->header();
+     }
+     return header.klass_or_null();
+   } else if (UseCompressedClassPointers) {
+      narrowKlass nklass = Atomic::load_acquire(&_metadata._compressed_klass);
+      return CompressedKlassPointers::decode(nklass);
+   } else
+ #endif
+   return Atomic::load_acquire(&_metadata._klass);
  }
  
  Klass* oopDesc::klass_raw() const {
!   return klass();
  }
  
  void oopDesc::set_klass(Klass* k) {
!   assert(Universe::is_bootstrapping() || (k != NULL && k->is_klass()), "incorrect Klass");
+   assert(!UseCompactObjectHeaders, "don't set Klass* with compact headers");
    if (UseCompressedClassPointers) {
      _metadata._compressed_klass = CompressedKlassPointers::encode_not_null(k);
    } else {
      _metadata._klass = k;
    }
  }
  
  void oopDesc::release_set_klass(HeapWord* mem, Klass* k) {
!   assert(Universe::is_bootstrapping() || (k != NULL && k->is_klass()), "incorrect Klass");
+   assert(!UseCompactObjectHeaders, "don't set Klass* with compact headers");
    char* raw_mem = ((char*)mem + klass_offset_in_bytes());
    if (UseCompressedClassPointers) {
      Atomic::release_store((narrowKlass*)raw_mem,
                            CompressedKlassPointers::encode_not_null(k));
    } else {
      Atomic::release_store((Klass**)raw_mem, k);
    }
  }
  
  void oopDesc::set_klass_gap(HeapWord* mem, int v) {
+   assert(!UseCompactObjectHeaders, "don't set Klass* gap with compact headers");
    if (UseCompressedClassPointers) {
      *(int*)(((char*)mem) + klass_gap_offset_in_bytes()) = v;
    }
  }
  

*** 269,31 ***
  }
  
  // Used by scavengers
  void oopDesc::forward_to(oop p) {
    markWord m = markWord::encode_pointer_as_mark(p);
!   assert(m.decode_pointer() == p, "encoding must be reversible");
    set_mark(m);
  }
  
  oop oopDesc::forward_to_atomic(oop p, markWord compare, atomic_memory_order order) {
    markWord m = markWord::encode_pointer_as_mark(p);
!   assert(m.decode_pointer() == p, "encoding must be reversible");
    markWord old_mark = cas_set_mark(m, compare, order);
    if (old_mark == compare) {
      return nullptr;
    } else {
!     return cast_to_oop(old_mark.decode_pointer());
    }
  }
  
  // Note that the forwardee is not the same thing as the displaced_mark.
  // The forwardee is used when copying during scavenge and mark-sweep.
  // It does need to clear the low two locking- and GC-related bits.
  oop oopDesc::forwardee() const {
!   assert(is_forwarded(), "only decode when actually forwarded");
!   return cast_to_oop(mark().decode_pointer());
  }
  
  // The following method needs to be MT safe.
  uint oopDesc::age() const {
    markWord m = mark();
--- 306,81 ---
  }
  
  // Used by scavengers
  void oopDesc::forward_to(oop p) {
    markWord m = markWord::encode_pointer_as_mark(p);
!   assert(forwardee(m) == p, "encoding must be reversable");
    set_mark(m);
  }
  
+ void oopDesc::forward_to_self() {
+ #ifdef _LP64
+   markWord m = mark();
+   // If mark is displaced, we need to preserve the Klass* from real header.
+   assert(SafepointSynchronize::is_at_safepoint(), "we can only safely fetch the displaced header at safepoint");
+   if (m.has_displaced_mark_helper()) {
+     m = m.displaced_mark_helper();
+   }
+   m = m.set_self_forwarded();
+   assert(forwardee(m) == cast_to_oop(this), "encoding must be reversable");
+   set_mark(m);
+ #else
+   forward_to(oop(this));
+ #endif
+ }
+ 
  oop oopDesc::forward_to_atomic(oop p, markWord compare, atomic_memory_order order) {
    markWord m = markWord::encode_pointer_as_mark(p);
!   assert(forwardee(m) == p, "encoding must be reversable");
    markWord old_mark = cas_set_mark(m, compare, order);
    if (old_mark == compare) {
      return nullptr;
    } else {
!     return forwardee(old_mark);
    }
  }
  
+ oop oopDesc::forward_to_self_atomic(markWord compare, atomic_memory_order order) {
+ #ifdef _LP64
+   markWord m = compare;
+   // If mark is displaced, we need to preserve the Klass* from real header.
+   assert(SafepointSynchronize::is_at_safepoint(), "we can only safely fetch the displaced header at safepoint");
+   if (m.has_displaced_mark_helper()) {
+     m = m.displaced_mark_helper();
+   }
+   m = m.set_self_forwarded();
+   assert(forwardee(m) == cast_to_oop(this), "encoding must be reversable");
+   markWord old_mark = cas_set_mark(m, compare, order);
+   if (old_mark == compare) {
+     return NULL;
+   } else {
+     assert(old_mark.is_marked(), "must be marked here");
+     return forwardee(old_mark);
+   }
+ #else
+   return forward_to_atomic(oop(this), compare, order);
+ #endif
+ }
+ 
  // Note that the forwardee is not the same thing as the displaced_mark.
  // The forwardee is used when copying during scavenge and mark-sweep.
  // It does need to clear the low two locking- and GC-related bits.
  oop oopDesc::forwardee() const {
!   return forwardee(mark());
! }
+ 
+ oop oopDesc::forwardee(markWord header) const {
+   assert(header.is_marked(), "must be forwarded");
+ #ifdef _LP64
+   if (header.self_forwarded()) {
+     return cast_to_oop(this);
+   } else
+ #endif
+   {
+     assert(header.is_marked(), "only decode when actually forwarded");
+     return cast_to_oop(header.decode_pointer());
+   }
  }
  
  // The following method needs to be MT safe.
  uint oopDesc::age() const {
    markWord m = mark();

*** 346,11 ***
    oop_iterate_backwards(cl, klass());
  }
  
  template <typename OopClosureType>
  void oopDesc::oop_iterate_backwards(OopClosureType* cl, Klass* k) {
-   assert(k == klass(), "wrong klass");
    OopIteratorClosureDispatch::oop_oop_iterate_backwards(cl, this, k);
  }
  
  bool oopDesc::is_instanceof_or_null(oop obj, Klass* klass) {
    return obj == nullptr || obj->klass()->is_subtype_of(klass);
--- 433,10 ---
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