--- a/src/hotspot/cpu/aarch64/macroAssembler_aarch64.cpp	Tue Jun 26 13:50:59 2018 -0700
+++ b/src/hotspot/cpu/aarch64/macroAssembler_aarch64.cpp	Tue Jun 26 16:59:38 2018 -0400
@@ -2127,8 +2127,7 @@
 
   bind(not_weak);
   // Resolve (untagged) jobject.
-  access_load_at(T_OBJECT, IN_CONCURRENT_ROOT, value, Address(value, 0), tmp,
-                 thread);
+  access_load_at(T_OBJECT, IN_NATIVE, value, Address(value, 0), tmp, thread);
   verify_oop(value);
   bind(done);
 }
@@ -3643,8 +3642,7 @@
 // ((OopHandle)result).resolve();
 void MacroAssembler::resolve_oop_handle(Register result, Register tmp) {
   // OopHandle::resolve is an indirection.
-  access_load_at(T_OBJECT, IN_CONCURRENT_ROOT,
-                 result, Address(result, 0), tmp, noreg);
+  access_load_at(T_OBJECT, IN_NATIVE, result, Address(result, 0), tmp, noreg);
 }
 
 void MacroAssembler::load_mirror(Register dst, Register method, Register tmp) {

--- a/src/hotspot/cpu/arm/gc/g1/g1BarrierSetAssembler_arm.cpp	Tue Jun 26 13:50:59 2018 -0700
+++ b/src/hotspot/cpu/arm/gc/g1/g1BarrierSetAssembler_arm.cpp	Tue Jun 26 16:59:38 2018 -0400
@@ -321,9 +321,10 @@
 void G1BarrierSetAssembler::oop_store_at(MacroAssembler* masm, DecoratorSet decorators, BasicType type,
                                          Address obj, Register new_val, Register tmp1, Register tmp2, Register tmp3, bool is_null) {
   bool in_heap = (decorators & IN_HEAP) != 0;
-  bool in_concurrent_root = (decorators & IN_CONCURRENT_ROOT) != 0;
+  bool as_normal = (decorators & AS_NORMAL) != 0;
+  assert((decorators & IS_DEST_UNINITIALIZED) == 0, "unsupported");
 
-  bool needs_pre_barrier = in_heap || in_concurrent_root;
+  bool needs_pre_barrier = as_normal;
   bool needs_post_barrier = (new_val != noreg) && in_heap;
 
   // flatten object address if needed
@@ -360,7 +361,7 @@
       g1_write_barrier_post(masm, store_addr, new_val, tmp1, tmp2, tmp3);
     }
   }
-};
+}
 
 #ifdef COMPILER1
 

--- a/src/hotspot/cpu/arm/macroAssembler_arm.cpp	Tue Jun 26 13:50:59 2018 -0700
+++ b/src/hotspot/cpu/arm/macroAssembler_arm.cpp	Tue Jun 26 16:59:38 2018 -0400
@@ -2140,7 +2140,7 @@
   b(done);
   bind(not_weak);
   // Resolve (untagged) jobject.
-  access_load_at(T_OBJECT, IN_CONCURRENT_ROOT,
+  access_load_at(T_OBJECT, IN_NATIVE,
                  Address(value, 0), value, tmp1, tmp2, noreg);
   verify_oop(value);
   bind(done);

--- a/src/hotspot/cpu/sparc/gc/g1/g1BarrierSetAssembler_sparc.cpp	Tue Jun 26 13:50:59 2018 -0700
+++ b/src/hotspot/cpu/sparc/gc/g1/g1BarrierSetAssembler_sparc.cpp	Tue Jun 26 16:59:38 2018 -0400
@@ -400,9 +400,10 @@
 void G1BarrierSetAssembler::oop_store_at(MacroAssembler* masm, DecoratorSet decorators, BasicType type,
                                          Register val, Address dst, Register tmp) {
   bool in_heap = (decorators & IN_HEAP) != 0;
-  bool in_concurrent_root = (decorators & IN_CONCURRENT_ROOT) != 0;
+  bool as_normal = (decorators & AS_NORMAL) != 0;
+  assert((decorators & IS_DEST_UNINITIALIZED) == 0, "unsupported");
 
-  bool needs_pre_barrier = in_heap || in_concurrent_root;
+  bool needs_pre_barrier = as_normal;
   // No need for post barrier if storing NULL
   bool needs_post_barrier = val != G0 && in_heap;
 

--- a/src/hotspot/cpu/sparc/macroAssembler_sparc.cpp	Tue Jun 26 13:50:59 2018 -0700
+++ b/src/hotspot/cpu/sparc/macroAssembler_sparc.cpp	Tue Jun 26 16:59:38 2018 -0400
@@ -182,8 +182,7 @@
   br (Assembler::always, true, Assembler::pt, done);
   delayed()->nop();
   bind(not_weak);
-  access_load_at(T_OBJECT, IN_CONCURRENT_ROOT,
-                 Address(value, 0), value, tmp);
+  access_load_at(T_OBJECT, IN_NATIVE, Address(value, 0), value, tmp);
   verify_oop(value);
   bind(done);
 }
@@ -3402,8 +3401,7 @@
 // ((OopHandle)result).resolve();
 void MacroAssembler::resolve_oop_handle(Register result, Register tmp) {
   // OopHandle::resolve is an indirection.
-  access_load_at(T_OBJECT, IN_CONCURRENT_ROOT,
-                 Address(result, 0), result, tmp);
+  access_load_at(T_OBJECT, IN_NATIVE, Address(result, 0), result, tmp);
 }
 
 void MacroAssembler::load_mirror(Register mirror, Register method, Register tmp) {

--- a/src/hotspot/cpu/x86/gc/g1/g1BarrierSetAssembler_x86.cpp	Tue Jun 26 13:50:59 2018 -0700
+++ b/src/hotspot/cpu/x86/gc/g1/g1BarrierSetAssembler_x86.cpp	Tue Jun 26 16:59:38 2018 -0400
@@ -349,9 +349,10 @@
 void G1BarrierSetAssembler::oop_store_at(MacroAssembler* masm, DecoratorSet decorators, BasicType type,
                                          Address dst, Register val, Register tmp1, Register tmp2) {
   bool in_heap = (decorators & IN_HEAP) != 0;
-  bool in_concurrent_root = (decorators & IN_CONCURRENT_ROOT) != 0;
+  bool as_normal = (decorators & AS_NORMAL) != 0;
+  assert((decorators & IS_DEST_UNINITIALIZED) == 0, "unsupported");
 
-  bool needs_pre_barrier = in_heap || in_concurrent_root;
+  bool needs_pre_barrier = as_normal;
   bool needs_post_barrier = val != noreg && in_heap;
 
   Register tmp3 = LP64_ONLY(r8) NOT_LP64(rsi);

--- a/src/hotspot/cpu/x86/macroAssembler_x86.cpp	Tue Jun 26 13:50:59 2018 -0700
+++ b/src/hotspot/cpu/x86/macroAssembler_x86.cpp	Tue Jun 26 16:59:38 2018 -0400
@@ -5238,8 +5238,7 @@
   jmp(done);
   bind(not_weak);
   // Resolve (untagged) jobject.
-  access_load_at(T_OBJECT, IN_CONCURRENT_ROOT,
-                 value, Address(value, 0), tmp, thread);
+  access_load_at(T_OBJECT, IN_NATIVE, value, Address(value, 0), tmp, thread);
   verify_oop(value);
   bind(done);
 }
@@ -6216,7 +6215,7 @@
   // Only 64 bit platforms support GCs that require a tmp register
   // Only IN_HEAP loads require a thread_tmp register
   // OopHandle::resolve is an indirection like jobject.
-  access_load_at(T_OBJECT, IN_CONCURRENT_ROOT,
+  access_load_at(T_OBJECT, IN_NATIVE,
                  result, Address(result, 0), tmp, /*tmp_thread*/noreg);
 }
 

--- a/src/hotspot/share/classfile/classLoaderData.cpp	Tue Jun 26 13:50:59 2018 -0700
+++ b/src/hotspot/share/classfile/classLoaderData.cpp	Tue Jun 26 16:59:38 2018 -0400
@@ -832,9 +832,7 @@
   oop* ptr = h.ptr_raw();
   if (ptr != NULL) {
     assert(_handles.owner_of(ptr), "Got unexpected handle " PTR_FORMAT, p2i(ptr));
-    // This root is not walked in safepoints, and hence requires an appropriate
-    // decorator that e.g. maintains the SATB invariant in SATB collectors.
-    NativeAccess<IN_CONCURRENT_ROOT>::oop_store(ptr, oop(NULL));
+    NativeAccess<>::oop_store(ptr, oop(NULL));
   }
 }
 

--- a/src/hotspot/share/gc/g1/c1/g1BarrierSetC1.cpp	Tue Jun 26 13:50:59 2018 -0700
+++ b/src/hotspot/share/gc/g1/c1/g1BarrierSetC1.cpp	Tue Jun 26 16:59:38 2018 -0400
@@ -52,11 +52,6 @@
                                  LIR_Opr pre_val, CodeEmitInfo* info) {
   LIRGenerator* gen = access.gen();
   DecoratorSet decorators = access.decorators();
-  bool in_heap = (decorators & IN_HEAP) != 0;
-  bool in_conc_root = (decorators & IN_CONCURRENT_ROOT) != 0;
-  if (!in_heap && !in_conc_root) {
-    return;
-  }
 
   // First we test whether marking is in progress.
   BasicType flag_type;

--- a/src/hotspot/share/gc/g1/g1BarrierSet.inline.hpp	Tue Jun 26 13:50:59 2018 -0700
+++ b/src/hotspot/share/gc/g1/g1BarrierSet.inline.hpp	Tue Jun 26 16:59:38 2018 -0400
@@ -98,12 +98,10 @@
 template <typename T>
 inline void G1BarrierSet::AccessBarrier<decorators, BarrierSetT>::
 oop_store_not_in_heap(T* addr, oop new_value) {
-  if (HasDecorator<decorators, IN_CONCURRENT_ROOT>::value) {
-    // For roots not scanned in a safepoint, we have to apply SATB barriers
-    // even for roots.
-    G1BarrierSet *bs = barrier_set_cast<G1BarrierSet>(BarrierSet::barrier_set());
-    bs->write_ref_field_pre<decorators>(addr);
-  }
+  // Apply SATB barriers for all non-heap references, to allow
+  // concurrent scanning of such references.
+  G1BarrierSet *bs = barrier_set_cast<G1BarrierSet>(BarrierSet::barrier_set());
+  bs->write_ref_field_pre<decorators>(addr);
   Raw::oop_store(addr, new_value);
 }
 

--- a/src/hotspot/share/gc/shared/stringdedup/stringDedupTable.cpp	Tue Jun 26 13:50:59 2018 -0700
+++ b/src/hotspot/share/gc/shared/stringdedup/stringDedupTable.cpp	Tue Jun 26 16:59:38 2018 -0400
@@ -281,13 +281,11 @@
                                       StringDedupEntry** list, uintx &count) {
   for (StringDedupEntry* entry = *list; entry != NULL; entry = entry->next()) {
     if (entry->hash() == hash && entry->latin1() == latin1) {
-      typeArrayOop existing_value = entry->obj();
-      if (equals(value, existing_value)) {
-        // Apply proper barrier to make sure it is kept alive. Concurrent mark might
-        // otherwise declare it dead if there are no other strong references to this object.
-        oop* obj_addr = (oop*)entry->obj_addr();
-        oop obj = NativeAccess<IN_CONCURRENT_ROOT | ON_WEAK_OOP_REF>::oop_load(obj_addr);
-        return typeArrayOop(obj);
+      oop* obj_addr = (oop*)entry->obj_addr();
+      oop obj = NativeAccess<ON_PHANTOM_OOP_REF | AS_NO_KEEPALIVE>::oop_load(obj_addr);
+      if (equals(value, static_cast<typeArrayOop>(obj))) {
+        obj = NativeAccess<ON_PHANTOM_OOP_REF>::oop_load(obj_addr);
+        return static_cast<typeArrayOop>(obj);
       }
     }
     count++;

--- a/src/hotspot/share/gc/z/c2/zBarrierSetC2.cpp	Tue Jun 26 13:50:59 2018 -0700
+++ b/src/hotspot/share/gc/z/c2/zBarrierSetC2.cpp	Tue Jun 26 16:59:38 2018 -0400
@@ -653,7 +653,6 @@
     return p;
   }
 
-  bool conc_root = (access.decorators() & IN_CONCURRENT_ROOT) != 0;
   bool weak = (access.decorators() & ON_WEAK_OOP_REF) != 0;
 
   GraphKit* kit = access.kit();

--- a/src/hotspot/share/gc/z/zBarrierSet.cpp	Tue Jun 26 13:50:59 2018 -0700
+++ b/src/hotspot/share/gc/z/zBarrierSet.cpp	Tue Jun 26 16:59:38 2018 -0400
@@ -48,12 +48,9 @@
   //assert((decorators & ON_UNKNOWN_OOP_REF) == 0, "Unexpected decorator");
 
   if (type == T_OBJECT || type == T_ARRAY) {
-    if (((decorators & IN_HEAP) != 0) ||
-        ((decorators & IN_CONCURRENT_ROOT) != 0) ||
-        ((decorators & ON_PHANTOM_OOP_REF) != 0)) {
-      // Barrier needed
-      return true;
-    }
+    assert((decorators & (IN_HEAP | IN_NATIVE)) != 0, "Where is reference?");
+    // Barrier needed even when IN_NATIVE, to allow concurrent scanning.
+    return true;
   }
 
   // Barrier not neeed

--- a/src/hotspot/share/oops/access.hpp	Tue Jun 26 13:50:59 2018 -0700
+++ b/src/hotspot/share/oops/access.hpp	Tue Jun 26 16:59:38 2018 -0400
@@ -375,8 +375,7 @@
   const DecoratorSet location_decorators = decorators & IN_DECORATOR_MASK;
   STATIC_ASSERT(location_decorators == 0 || ( // make sure location decorators are disjoint if set
     (location_decorators ^ IN_NATIVE) == 0 ||
-    (location_decorators ^ IN_HEAP) == 0 ||
-    (location_decorators ^ (IN_NATIVE | IN_CONCURRENT_ROOT)) == 0
+    (location_decorators ^ IN_HEAP) == 0
   ));
 }
 

--- a/src/hotspot/share/oops/accessDecorators.hpp	Tue Jun 26 13:50:59 2018 -0700
+++ b/src/hotspot/share/oops/accessDecorators.hpp	Tue Jun 26 16:59:38 2018 -0400
@@ -153,8 +153,8 @@
 //   Note that primitive accesses will only be resolved on the barrier set if the appropriate build-time
 //   decorator for enabling primitive barriers is enabled for the build.
 const DecoratorSet AS_RAW                  = UCONST64(1) << 12;
-const DecoratorSet AS_NO_KEEPALIVE         = UCONST64(1) << 14;
-const DecoratorSet AS_NORMAL               = UCONST64(1) << 15;
+const DecoratorSet AS_NO_KEEPALIVE         = UCONST64(1) << 13;
+const DecoratorSet AS_NORMAL               = UCONST64(1) << 14;
 const DecoratorSet AS_DECORATOR_MASK       = AS_RAW | AS_NO_KEEPALIVE | AS_NORMAL;
 
 // === Reference Strength Decorators ===
@@ -166,10 +166,10 @@
 // * ON_UNKNOWN_OOP_REF: The memory access is performed on a reference of unknown strength.
 //   This could for example come from the unsafe API.
 // * Default (no explicit reference strength specified): ON_STRONG_OOP_REF
-const DecoratorSet ON_STRONG_OOP_REF  = UCONST64(1) << 16;
-const DecoratorSet ON_WEAK_OOP_REF    = UCONST64(1) << 17;
-const DecoratorSet ON_PHANTOM_OOP_REF = UCONST64(1) << 18;
-const DecoratorSet ON_UNKNOWN_OOP_REF = UCONST64(1) << 19;
+const DecoratorSet ON_STRONG_OOP_REF  = UCONST64(1) << 15;
+const DecoratorSet ON_WEAK_OOP_REF    = UCONST64(1) << 16;
+const DecoratorSet ON_PHANTOM_OOP_REF = UCONST64(1) << 17;
+const DecoratorSet ON_UNKNOWN_OOP_REF = UCONST64(1) << 18;
 const DecoratorSet ON_DECORATOR_MASK  = ON_STRONG_OOP_REF | ON_WEAK_OOP_REF |
                                         ON_PHANTOM_OOP_REF | ON_UNKNOWN_OOP_REF;
 
@@ -179,13 +179,9 @@
 // * IN_HEAP: The access is performed in the heap. Many barriers such as card marking will
 //   be omitted if this decorator is not set.
 // * IN_NATIVE: The access is performed in an off-heap data structure pointing into the Java heap.
-// * IN_CONCURRENT_ROOT: The access is performed in an off-heap data structure pointing into the Java heap,
-//   but is notably not scanned during safepoints. This is sometimes a special case for some GCs and
-//   implies that it is also an IN_NATIVE.
-const DecoratorSet IN_HEAP            = UCONST64(1) << 20;
-const DecoratorSet IN_NATIVE          = UCONST64(1) << 22;
-const DecoratorSet IN_CONCURRENT_ROOT = UCONST64(1) << 23;
-const DecoratorSet IN_DECORATOR_MASK  = IN_HEAP | IN_NATIVE | IN_CONCURRENT_ROOT;
+const DecoratorSet IN_HEAP            = UCONST64(1) << 19;
+const DecoratorSet IN_NATIVE          = UCONST64(1) << 20;
+const DecoratorSet IN_DECORATOR_MASK  = IN_HEAP | IN_NATIVE;
 
 // == Boolean Flag Decorators ==
 // * IS_ARRAY: The access is performed on a heap allocated array. This is sometimes a special case
@@ -194,8 +190,8 @@
 //   marking that the previous value is uninitialized nonsense rather than a real value.
 // * IS_NOT_NULL: This property can make certain barriers faster such as compressing oops.
 const DecoratorSet IS_ARRAY              = UCONST64(1) << 21;
-const DecoratorSet IS_DEST_UNINITIALIZED = UCONST64(1) << 13;
-const DecoratorSet IS_NOT_NULL           = UCONST64(1) << 25;
+const DecoratorSet IS_DEST_UNINITIALIZED = UCONST64(1) << 22;
+const DecoratorSet IS_NOT_NULL           = UCONST64(1) << 23;
 
 // == Arraycopy Decorators ==
 // * ARRAYCOPY_CHECKCAST: This property means that the class of the objects in source
@@ -207,17 +203,17 @@
 // * ARRAYCOPY_ARRAYOF: The copy is in the arrayof form.
 // * ARRAYCOPY_ATOMIC: The accesses have to be atomic over the size of its elements.
 // * ARRAYCOPY_ALIGNED: The accesses have to be aligned on a HeapWord.
-const DecoratorSet ARRAYCOPY_CHECKCAST            = UCONST64(1) << 26;
-const DecoratorSet ARRAYCOPY_DISJOINT             = UCONST64(1) << 27;
-const DecoratorSet ARRAYCOPY_ARRAYOF              = UCONST64(1) << 28;
-const DecoratorSet ARRAYCOPY_ATOMIC               = UCONST64(1) << 29;
-const DecoratorSet ARRAYCOPY_ALIGNED              = UCONST64(1) << 30;
+const DecoratorSet ARRAYCOPY_CHECKCAST            = UCONST64(1) << 24;
+const DecoratorSet ARRAYCOPY_DISJOINT             = UCONST64(1) << 25;
+const DecoratorSet ARRAYCOPY_ARRAYOF              = UCONST64(1) << 26;
+const DecoratorSet ARRAYCOPY_ATOMIC               = UCONST64(1) << 27;
+const DecoratorSet ARRAYCOPY_ALIGNED              = UCONST64(1) << 28;
 const DecoratorSet ARRAYCOPY_DECORATOR_MASK       = ARRAYCOPY_CHECKCAST | ARRAYCOPY_DISJOINT |
                                                     ARRAYCOPY_DISJOINT | ARRAYCOPY_ARRAYOF |
                                                     ARRAYCOPY_ATOMIC | ARRAYCOPY_ALIGNED;
 
 // Keep track of the last decorator.
-const DecoratorSet DECORATOR_LAST = UCONST64(1) << 30;
+const DecoratorSet DECORATOR_LAST = UCONST64(1) << 28;
 
 namespace AccessInternal {
   // This class adds implied decorators that follow according to decorator rules.
@@ -235,9 +231,7 @@
     // If no barrier strength has been picked, normal will be used
     static const DecoratorSet barrier_strength_default = memory_ordering_default |
       ((AS_DECORATOR_MASK & memory_ordering_default) == 0 ? AS_NORMAL : INTERNAL_EMPTY);
-    static const DecoratorSet conc_root_is_root = barrier_strength_default |
-      ((IN_CONCURRENT_ROOT & barrier_strength_default) != 0 ? IN_NATIVE : INTERNAL_EMPTY);
-    static const DecoratorSet value = conc_root_is_root | BT_BUILDTIME_DECORATORS;
+    static const DecoratorSet value = barrier_strength_default | BT_BUILDTIME_DECORATORS;
   };
 
   // This function implements the above DecoratorFixup rules, but without meta
@@ -253,9 +247,7 @@
     // If no barrier strength has been picked, normal will be used
     DecoratorSet barrier_strength_default = memory_ordering_default |
       ((AS_DECORATOR_MASK & memory_ordering_default) == 0 ? AS_NORMAL : INTERNAL_EMPTY);
-    DecoratorSet conc_root_is_root = barrier_strength_default |
-      ((IN_CONCURRENT_ROOT & barrier_strength_default) != 0 ? IN_NATIVE : INTERNAL_EMPTY);
-    DecoratorSet value = conc_root_is_root | BT_BUILDTIME_DECORATORS;
+    DecoratorSet value = barrier_strength_default | BT_BUILDTIME_DECORATORS;
     return value;
   }
 }

--- a/src/hotspot/share/oops/oopHandle.inline.hpp	Tue Jun 26 13:50:59 2018 -0700
+++ b/src/hotspot/share/oops/oopHandle.inline.hpp	Tue Jun 26 16:59:38 2018 -0400
@@ -29,7 +29,7 @@
 #include "oops/oopHandle.hpp"
 
 inline oop OopHandle::resolve() const {
-  return (_obj == NULL) ? (oop)NULL : NativeAccess<IN_CONCURRENT_ROOT>::oop_load(_obj);
+  return (_obj == NULL) ? (oop)NULL : NativeAccess<>::oop_load(_obj);
 }
 
 #endif //  SHARE_VM_OOPS_OOPHANDLE_INLINE_HPP

--- a/src/hotspot/share/runtime/jniHandles.cpp	Tue Jun 26 13:50:59 2018 -0700
+++ b/src/hotspot/share/runtime/jniHandles.cpp	Tue Jun 26 16:59:38 2018 -0400
@@ -109,7 +109,7 @@
     // Return NULL on allocation failure.
     if (ptr != NULL) {
       assert(*ptr == NULL, "invariant");
-      NativeAccess<IN_CONCURRENT_ROOT>::oop_store(ptr, obj());
+      NativeAccess<>::oop_store(ptr, obj());
       res = reinterpret_cast<jobject>(ptr);
     } else {
       report_handle_allocation_failure(alloc_failmode, "global");
@@ -175,7 +175,7 @@
   if (handle != NULL) {
     assert(!is_jweak(handle), "wrong method for detroying jweak");
     oop* oop_ptr = jobject_ptr(handle);
-    NativeAccess<IN_CONCURRENT_ROOT>::oop_store(oop_ptr, (oop)NULL);
+    NativeAccess<>::oop_store(oop_ptr, (oop)NULL);
     global_handles()->release(oop_ptr);
   }
 }

--- a/src/hotspot/share/runtime/jniHandles.inline.hpp	Tue Jun 26 13:50:59 2018 -0700
+++ b/src/hotspot/share/runtime/jniHandles.inline.hpp	Tue Jun 26 16:59:38 2018 -0400
@@ -57,7 +57,7 @@
   if (is_jweak(handle)) {       // Unlikely
     result = resolve_jweak(handle);
   } else {
-    result = NativeAccess<IN_CONCURRENT_ROOT>::oop_load(jobject_ptr(handle));
+    result = NativeAccess<>::oop_load(jobject_ptr(handle));
     // Construction of jobjects canonicalize a null value into a null
     // jobject, so for non-jweak the pointee should never be null.
     assert(external_guard || result != NULL, "Invalid JNI handle");