# HG changeset patch
# User kbarrett
# Date 1518561382 18000
# Node ID e6eb66d2e7656a06ad38b4becf46b3c0426f3386
# Parent  be873d8c0114442f18b182546835fa2e87fbf7dd
8197454: Need Access decorator for storing oop into uninitialized location
Summary: Repurpose ARRAYCOPY_DEST_NOT_INITIALIZED to AS_DEST_NOT_INITIALIZED.
Reviewed-by: eosterlund, coleenp

diff -r be873d8c0114 -r e6eb66d2e765 src/hotspot/share/gc/g1/g1SATBCardTableModRefBS.inline.hpp
--- a/src/hotspot/share/gc/g1/g1SATBCardTableModRefBS.inline.hpp	Tue Feb 13 17:38:03 2018 +0100
+++ b/src/hotspot/share/gc/g1/g1SATBCardTableModRefBS.inline.hpp	Tue Feb 13 17:36:22 2018 -0500
@@ -30,7 +30,7 @@
 
 template <DecoratorSet decorators, typename T>
 inline void G1SATBCardTableModRefBS::write_ref_field_pre(T* field) {
-  if (HasDecorator<decorators, ARRAYCOPY_DEST_NOT_INITIALIZED>::value ||
+  if (HasDecorator<decorators, AS_DEST_NOT_INITIALIZED>::value ||
       HasDecorator<decorators, AS_NO_KEEPALIVE>::value) {
     return;
   }
diff -r be873d8c0114 -r e6eb66d2e765 src/hotspot/share/gc/shared/modRefBarrierSet.inline.hpp
--- a/src/hotspot/share/gc/shared/modRefBarrierSet.inline.hpp	Tue Feb 13 17:38:03 2018 +0100
+++ b/src/hotspot/share/gc/shared/modRefBarrierSet.inline.hpp	Tue Feb 13 17:36:22 2018 -0500
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2017, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2017, 2018, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -73,7 +73,7 @@
   if (!HasDecorator<decorators, ARRAYCOPY_CHECKCAST>::value) {
     // Optimized covariant case
     bs->write_ref_array_pre(dst, (int)length,
-                            HasDecorator<decorators, ARRAYCOPY_DEST_NOT_INITIALIZED>::value);
+                            HasDecorator<decorators, AS_DEST_NOT_INITIALIZED>::value);
     Raw::oop_arraycopy(src_obj, dst_obj, src, dst, length);
     bs->write_ref_array((HeapWord*)dst, length);
   } else {
diff -r be873d8c0114 -r e6eb66d2e765 src/hotspot/share/oops/access.hpp
--- a/src/hotspot/share/oops/access.hpp	Tue Feb 13 17:38:03 2018 +0100
+++ b/src/hotspot/share/oops/access.hpp	Tue Feb 13 17:36:22 2018 -0500
@@ -155,6 +155,8 @@
 //  - Accesses on narrowOop* translate to encoded/decoded memory accesses without runtime checks
 //  - Accesses on HeapWord* translate to a runtime check choosing one of the above
 //  - Accesses on other types translate to raw memory accesses without runtime checks
+// * AS_DEST_NOT_INITIALIZED: This property can be important to e.g. SATB barriers by
+//   marking that the previous value is uninitialized nonsense rather than a real value.
 // * AS_NO_KEEPALIVE: The barrier is used only on oop references and will not keep any involved objects
 //   alive, regardless of the type of reference being accessed. It will however perform the memory access
 //   in a consistent way w.r.t. e.g. concurrent compaction, so that the right field is being accessed,
@@ -164,10 +166,12 @@
 //   responsibility of performing the access and what barriers to be performed to the GC. This is the default.
 //   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) << 11;
-const DecoratorSet AS_NO_KEEPALIVE   = UCONST64(1) << 12;
-const DecoratorSet AS_NORMAL         = UCONST64(1) << 13;
-const DecoratorSet AS_DECORATOR_MASK = AS_RAW | AS_NO_KEEPALIVE | AS_NORMAL;
+const DecoratorSet AS_RAW                  = UCONST64(1) << 11;
+const DecoratorSet AS_DEST_NOT_INITIALIZED = UCONST64(1) << 12;
+const DecoratorSet AS_NO_KEEPALIVE         = UCONST64(1) << 13;
+const DecoratorSet AS_NORMAL               = UCONST64(1) << 14;
+const DecoratorSet AS_DECORATOR_MASK       = AS_RAW | AS_DEST_NOT_INITIALIZED |
+                                             AS_NO_KEEPALIVE | AS_NORMAL;
 
 // === Reference Strength Decorators ===
 // These decorators only apply to accesses on oop-like types (oop/narrowOop).
@@ -178,10 +182,10 @@
 // * 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) << 14;
-const DecoratorSet ON_WEAK_OOP_REF    = UCONST64(1) << 15;
-const DecoratorSet ON_PHANTOM_OOP_REF = UCONST64(1) << 16;
-const DecoratorSet ON_UNKNOWN_OOP_REF = UCONST64(1) << 17;
+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;
 
@@ -196,23 +200,21 @@
 // * 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_ROOT.
-const DecoratorSet IN_HEAP            = UCONST64(1) << 18;
-const DecoratorSet IN_HEAP_ARRAY      = UCONST64(1) << 19;
-const DecoratorSet IN_ROOT            = UCONST64(1) << 20;
-const DecoratorSet IN_CONCURRENT_ROOT = UCONST64(1) << 21;
-const DecoratorSet IN_ARCHIVE_ROOT    = UCONST64(1) << 22;
+const DecoratorSet IN_HEAP            = UCONST64(1) << 19;
+const DecoratorSet IN_HEAP_ARRAY      = UCONST64(1) << 20;
+const DecoratorSet IN_ROOT            = UCONST64(1) << 21;
+const DecoratorSet IN_CONCURRENT_ROOT = UCONST64(1) << 22;
+const DecoratorSet IN_ARCHIVE_ROOT    = UCONST64(1) << 23;
 const DecoratorSet IN_DECORATOR_MASK  = IN_HEAP | IN_HEAP_ARRAY |
                                         IN_ROOT | IN_CONCURRENT_ROOT |
                                         IN_ARCHIVE_ROOT;
 
 // == Value Decorators ==
 // * OOP_NOT_NULL: This property can make certain barriers faster such as compressing oops.
-const DecoratorSet OOP_NOT_NULL       = UCONST64(1) << 23;
+const DecoratorSet OOP_NOT_NULL       = UCONST64(1) << 24;
 const DecoratorSet OOP_DECORATOR_MASK = OOP_NOT_NULL;
 
 // == Arraycopy Decorators ==
-// * ARRAYCOPY_DEST_NOT_INITIALIZED: This property can be important to e.g. SATB barriers by
-//   marking that the previous value uninitialized nonsense rather than a real value.
 // * ARRAYCOPY_CHECKCAST: This property means that the class of the objects in source
 //   are not guaranteed to be subclasses of the class of the destination array. This requires
 //   a check-cast barrier during the copying operation. If this is not set, it is assumed
@@ -222,14 +224,12 @@
 // * 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_DEST_NOT_INITIALIZED = UCONST64(1) << 24;
 const DecoratorSet ARRAYCOPY_CHECKCAST            = UCONST64(1) << 25;
 const DecoratorSet ARRAYCOPY_DISJOINT             = UCONST64(1) << 26;
 const DecoratorSet ARRAYCOPY_ARRAYOF              = UCONST64(1) << 27;
 const DecoratorSet ARRAYCOPY_ATOMIC               = UCONST64(1) << 28;
 const DecoratorSet ARRAYCOPY_ALIGNED              = UCONST64(1) << 29;
-const DecoratorSet ARRAYCOPY_DECORATOR_MASK       = ARRAYCOPY_DEST_NOT_INITIALIZED |
-                                                    ARRAYCOPY_CHECKCAST | ARRAYCOPY_DISJOINT |
+const DecoratorSet ARRAYCOPY_DECORATOR_MASK       = ARRAYCOPY_CHECKCAST | ARRAYCOPY_DISJOINT |
                                                     ARRAYCOPY_DISJOINT | ARRAYCOPY_ARRAYOF |
                                                     ARRAYCOPY_ATOMIC | ARRAYCOPY_ALIGNED;
 
@@ -343,8 +343,8 @@
 
   template <DecoratorSet expected_mo_decorators>
   static void verify_primitive_decorators() {
-    const DecoratorSet primitive_decorators = (AS_DECORATOR_MASK ^ AS_NO_KEEPALIVE) | IN_HEAP |
-                                               IN_HEAP_ARRAY;
+    const DecoratorSet primitive_decorators = (AS_DECORATOR_MASK ^ AS_NO_KEEPALIVE ^ AS_DEST_NOT_INITIALIZED) |
+                                              IN_HEAP | IN_HEAP_ARRAY;
     verify_decorators<expected_mo_decorators | primitive_decorators>();
   }
 
diff -r be873d8c0114 -r e6eb66d2e765 src/hotspot/share/oops/access.inline.hpp
--- a/src/hotspot/share/oops/access.inline.hpp	Tue Feb 13 17:38:03 2018 +0100
+++ b/src/hotspot/share/oops/access.inline.hpp	Tue Feb 13 17:36:22 2018 -0500
@@ -1060,6 +1060,7 @@
   const DecoratorSet barrier_strength_decorators = decorators & AS_DECORATOR_MASK;
   STATIC_ASSERT(barrier_strength_decorators == 0 || ( // make sure barrier strength decorators are disjoint if set
     (barrier_strength_decorators ^ AS_NO_KEEPALIVE) == 0 ||
+    (barrier_strength_decorators ^ AS_DEST_NOT_INITIALIZED) == 0 ||
     (barrier_strength_decorators ^ AS_RAW) == 0 ||
     (barrier_strength_decorators ^ AS_NORMAL) == 0
   ));
diff -r be873d8c0114 -r e6eb66d2e765 src/hotspot/share/runtime/stubRoutines.cpp
--- a/src/hotspot/share/runtime/stubRoutines.cpp	Tue Feb 13 17:38:03 2018 +0100
+++ b/src/hotspot/share/runtime/stubRoutines.cpp	Tue Feb 13 17:36:22 2018 -0500
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1997, 2017, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2018, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -418,7 +418,7 @@
   SharedRuntime::_oop_array_copy_ctr++;        // Slow-path oop array copy
 #endif // !PRODUCT
   assert(count != 0, "count should be non-zero");
-  HeapAccess<ARRAYCOPY_DEST_NOT_INITIALIZED>::oop_arraycopy(NULL, NULL, (HeapWord*)src, (HeapWord*)dest, count);
+  HeapAccess<AS_DEST_NOT_INITIALIZED>::oop_arraycopy(NULL, NULL, (HeapWord*)src, (HeapWord*)dest, count);
 JRT_END
 
 JRT_LEAF(void, StubRoutines::arrayof_jbyte_copy(HeapWord* src, HeapWord* dest, size_t count))
@@ -462,7 +462,7 @@
   SharedRuntime::_oop_array_copy_ctr++;        // Slow-path oop array copy
 #endif // !PRODUCT
   assert(count != 0, "count should be non-zero");
-  HeapAccess<ARRAYCOPY_ARRAYOF | ARRAYCOPY_DEST_NOT_INITIALIZED>::oop_arraycopy(NULL, NULL, src, dest, count);
+  HeapAccess<ARRAYCOPY_ARRAYOF | AS_DEST_NOT_INITIALIZED>::oop_arraycopy(NULL, NULL, src, dest, count);
 JRT_END
 
 address StubRoutines::select_fill_function(BasicType t, bool aligned, const char* &name) {