--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hotspot/share/oops/access.hpp Mon Nov 20 13:07:44 2017 +0100
@@ -0,0 +1,519 @@
+/*
+ * Copyright (c) 2017, 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
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+#ifndef SHARE_VM_RUNTIME_ACCESS_HPP
+#define SHARE_VM_RUNTIME_ACCESS_HPP
+
+#include "memory/allocation.hpp"
+#include "metaprogramming/decay.hpp"
+#include "metaprogramming/integralConstant.hpp"
+#include "oops/oopsHierarchy.hpp"
+#include "utilities/debug.hpp"
+#include "utilities/globalDefinitions.hpp"
+
+// = GENERAL =
+// Access is an API for performing accesses with declarative semantics. Each access can have a number of "decorators".
+// A decorator is an attribute or property that affects the way a memory access is performed in some way.
+// There are different groups of decorators. Some have to do with memory ordering, others to do with,
+// e.g. strength of references, strength of GC barriers, or whether compression should be applied or not.
+// Some decorators are set at buildtime, such as whether primitives require GC barriers or not, others
+// at callsites such as whether an access is in the heap or not, and others are resolved at runtime
+// such as GC-specific barriers and encoding/decoding compressed oops.
+// By pipelining handling of these decorators, the design of the Access API allows separation of concern
+// over the different orthogonal concerns of decorators, while providing a powerful way of
+// expressing these orthogonal semantic properties in a unified way.
+
+// == OPERATIONS ==
+// * load: Load a value from an address.
+// * load_at: Load a value from an internal pointer relative to a base object.
+// * store: Store a value at an address.
+// * store_at: Store a value in an internal pointer relative to a base object.
+// * atomic_cmpxchg: Atomically compare-and-swap a new value at an address if previous value matched the compared value.
+// * atomic_cmpxchg_at: Atomically compare-and-swap a new value at an internal pointer address if previous value matched the compared value.
+// * atomic_xchg: Atomically swap a new value at an address if previous value matched the compared value.
+// * atomic_xchg_at: Atomically swap a new value at an internal pointer address if previous value matched the compared value.
+// * arraycopy: Copy data from one heap array to another heap array.
+// * clone: Clone the contents of an object to a newly allocated object.
+
+typedef uint64_t DecoratorSet;
+
+// == Internal Decorators - do not use ==
+// * INTERNAL_EMPTY: This is the name for the empty decorator set (in absence of other decorators).
+// * INTERNAL_CONVERT_COMPRESSED_OOPS: This is an oop access that will require converting an oop
+// to a narrowOop or vice versa, if UseCompressedOops is known to be set.
+// * INTERNAL_VALUE_IS_OOP: Remember that the involved access is on oop rather than primitive.
+const DecoratorSet INTERNAL_EMPTY = UCONST64(0);
+const DecoratorSet INTERNAL_CONVERT_COMPRESSED_OOP = UCONST64(1) << 1;
+const DecoratorSet INTERNAL_VALUE_IS_OOP = UCONST64(1) << 2;
+
+// == Internal build-time Decorators ==
+// * INTERNAL_BT_BARRIER_ON_PRIMITIVES: This is set in the barrierSetConfig.hpp file.
+const DecoratorSet INTERNAL_BT_BARRIER_ON_PRIMITIVES = UCONST64(1) << 3;
+
+// == Internal run-time Decorators ==
+// * INTERNAL_RT_USE_COMPRESSED_OOPS: This decorator will be set in runtime resolved
+// access backends iff UseCompressedOops is true.
+const DecoratorSet INTERNAL_RT_USE_COMPRESSED_OOPS = UCONST64(1) << 4;
+
+const DecoratorSet INTERNAL_DECORATOR_MASK = INTERNAL_CONVERT_COMPRESSED_OOP | INTERNAL_VALUE_IS_OOP |
+ INTERNAL_BT_BARRIER_ON_PRIMITIVES | INTERNAL_RT_USE_COMPRESSED_OOPS;
+
+// == Memory Ordering Decorators ==
+// The memory ordering decorators can be described in the following way:
+// === Decorator Rules ===
+// The different types of memory ordering guarantees have a strict order of strength.
+// Explicitly specifying the stronger ordering implies that the guarantees of the weaker
+// property holds too. The names come from the C++11 atomic operations, and typically
+// have a JMM equivalent property.
+// The equivalence may be viewed like this:
+// MO_UNORDERED is equivalent to JMM plain.
+// MO_VOLATILE has no equivalence in JMM, because it's a C++ thing.
+// MO_RELAXED is equivalent to JMM opaque.
+// MO_ACQUIRE is equivalent to JMM acquire.
+// MO_RELEASE is equivalent to JMM release.
+// MO_SEQ_CST is equivalent to JMM volatile.
+//
+// === Stores ===
+// * MO_UNORDERED (Default): No guarantees.
+// - The compiler and hardware are free to reorder aggressively. And they will.
+// * MO_VOLATILE: Volatile stores (in the C++ sense).
+// - The stores are not reordered by the compiler (but possibly the HW) w.r.t. other
+// volatile accesses in program order (but possibly non-volatile accesses).
+// * MO_RELAXED: Relaxed atomic stores.
+// - The stores are atomic.
+// - Guarantees from volatile stores hold.
+// * MO_RELEASE: Releasing stores.
+// - The releasing store will make its preceding memory accesses observable to memory accesses
+// subsequent to an acquiring load observing this releasing store.
+// - Guarantees from relaxed stores hold.
+// * MO_SEQ_CST: Sequentially consistent stores.
+// - The stores are observed in the same order by MO_SEQ_CST loads on other processors
+// - Preceding loads and stores in program order are not reordered with subsequent loads and stores in program order.
+// - Guarantees from releasing stores hold.
+// === Loads ===
+// * MO_UNORDERED (Default): No guarantees
+// - The compiler and hardware are free to reorder aggressively. And they will.
+// * MO_VOLATILE: Volatile loads (in the C++ sense).
+// - The loads are not reordered by the compiler (but possibly the HW) w.r.t. other
+// volatile accesses in program order (but possibly non-volatile accesses).
+// * MO_RELAXED: Relaxed atomic loads.
+// - The stores are atomic.
+// - Guarantees from volatile loads hold.
+// * MO_ACQUIRE: Acquiring loads.
+// - An acquiring load will make subsequent memory accesses observe the memory accesses
+// preceding the releasing store that the acquiring load observed.
+// - Guarantees from relaxed loads hold.
+// * MO_SEQ_CST: Sequentially consistent loads.
+// - These loads observe MO_SEQ_CST stores in the same order on other processors
+// - Preceding loads and stores in program order are not reordered with subsequent loads and stores in program order.
+// - Guarantees from acquiring loads hold.
+// === Atomic Cmpxchg ===
+// * MO_RELAXED: Atomic but relaxed cmpxchg.
+// - Guarantees from MO_RELAXED loads and MO_RELAXED stores hold unconditionally.
+// * MO_SEQ_CST: Sequentially consistent cmpxchg.
+// - Guarantees from MO_SEQ_CST loads and MO_SEQ_CST stores hold unconditionally.
+// === Atomic Xchg ===
+// * MO_RELAXED: Atomic but relaxed atomic xchg.
+// - Guarantees from MO_RELAXED loads and MO_RELAXED stores hold.
+// * MO_SEQ_CST: Sequentially consistent xchg.
+// - Guarantees from MO_SEQ_CST loads and MO_SEQ_CST stores hold.
+const DecoratorSet MO_UNORDERED = UCONST64(1) << 5;
+const DecoratorSet MO_VOLATILE = UCONST64(1) << 6;
+const DecoratorSet MO_RELAXED = UCONST64(1) << 7;
+const DecoratorSet MO_ACQUIRE = UCONST64(1) << 8;
+const DecoratorSet MO_RELEASE = UCONST64(1) << 9;
+const DecoratorSet MO_SEQ_CST = UCONST64(1) << 10;
+const DecoratorSet MO_DECORATOR_MASK = MO_UNORDERED | MO_VOLATILE | MO_RELAXED |
+ MO_ACQUIRE | MO_RELEASE | MO_SEQ_CST;
+
+// === Barrier Strength Decorators ===
+// * AS_RAW: The access will translate into a raw memory access, hence ignoring all semantic concerns
+// except memory ordering and compressed oops. This will bypass runtime function pointer dispatching
+// in the pipeline and hardwire to raw accesses without going trough the GC access barriers.
+// - Accesses on oop* translate to raw memory accesses without runtime checks
+// - 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_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,
+// or maintain, e.g. intergenerational or interregional pointers if applicable. This should be used with
+// extreme caution in isolated scopes.
+// * AS_NORMAL: The accesses will be resolved to an accessor on the BarrierSet class, giving the
+// 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;
+
+// === Reference Strength Decorators ===
+// These decorators only apply to accesses on oop-like types (oop/narrowOop).
+// * ON_STRONG_OOP_REF: Memory access is performed on a strongly reachable reference.
+// * ON_WEAK_OOP_REF: The memory access is performed on a weakly reachable reference.
+// * ON_PHANTOM_OOP_REF: The memory access is performed on a phantomly reachable reference.
+// This is the same ring of strength as jweak and weak oops in the VM.
+// * 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_DECORATOR_MASK = ON_STRONG_OOP_REF | ON_WEAK_OOP_REF |
+ ON_PHANTOM_OOP_REF | ON_UNKNOWN_OOP_REF;
+
+// === Access Location ===
+// Accesses can take place in, e.g. the heap, old or young generation and different native roots.
+// The location is important to the GC as it may imply different actions. The following decorators are used:
+// * 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_HEAP_ARRAY: The access is performed on a heap allocated array. This is sometimes a special case
+// for some GCs, and implies that it is an IN_HEAP.
+// * IN_ROOT: 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_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_DECORATOR_MASK = IN_HEAP | IN_HEAP_ARRAY |
+ IN_ROOT | IN_CONCURRENT_ROOT;
+
+// == Value Decorators ==
+// * OOP_NOT_NULL: This property can make certain barriers faster such as compressing oops.
+const DecoratorSet OOP_NOT_NULL = UCONST64(1) << 22;
+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
+// that the array is covariant: (the source array type is-a destination array type)
+// * ARRAYCOPY_DISJOINT: This property means that it is known that the two array ranges
+// are disjoint.
+// * 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 |
+ ARRAYCOPY_DISJOINT | ARRAYCOPY_ARRAYOF |
+ ARRAYCOPY_ATOMIC | ARRAYCOPY_ALIGNED;
+
+// The HasDecorator trait can help at compile-time determining whether a decorator set
+// has an intersection with a certain other decorator set
+template <DecoratorSet decorators, DecoratorSet decorator>
+struct HasDecorator: public IntegralConstant<bool, (decorators & decorator) != 0> {};
+
+namespace AccessInternal {
+ template <typename T>
+ struct OopOrNarrowOopInternal: AllStatic {
+ typedef oop type;
+ };
+
+ template <>
+ struct OopOrNarrowOopInternal<narrowOop>: AllStatic {
+ typedef narrowOop type;
+ };
+
+ // This metafunction returns a canonicalized oop/narrowOop type for a passed
+ // in oop-like types passed in from oop_* overloads where the user has sworn
+ // that the passed in values should be oop-like (e.g. oop, oopDesc*, arrayOop,
+ // narrowOoop, instanceOopDesc*, and random other things).
+ // In the oop_* overloads, it must hold that if the passed in type T is not
+ // narrowOop, then it by contract has to be one of many oop-like types implicitly
+ // convertible to oop, and hence returns oop as the canonical oop type.
+ // If it turns out it was not, then the implicit conversion to oop will fail
+ // to compile, as desired.
+ template <typename T>
+ struct OopOrNarrowOop: AllStatic {
+ typedef typename OopOrNarrowOopInternal<typename Decay<T>::type>::type type;
+ };
+
+ inline void* field_addr(oop base, ptrdiff_t byte_offset) {
+ return reinterpret_cast<void*>(reinterpret_cast<intptr_t>((void*)base) + byte_offset);
+ }
+
+ template <DecoratorSet decorators, typename T>
+ void store_at(oop base, ptrdiff_t offset, T value);
+
+ template <DecoratorSet decorators, typename T>
+ T load_at(oop base, ptrdiff_t offset);
+
+ template <DecoratorSet decorators, typename T>
+ T atomic_cmpxchg_at(T new_value, oop base, ptrdiff_t offset, T compare_value);
+
+ template <DecoratorSet decorators, typename T>
+ T atomic_xchg_at(T new_value, oop base, ptrdiff_t offset);
+
+ template <DecoratorSet decorators, typename P, typename T>
+ void store(P* addr, T value);
+
+ template <DecoratorSet decorators, typename P, typename T>
+ T load(P* addr);
+
+ template <DecoratorSet decorators, typename P, typename T>
+ T atomic_cmpxchg(T new_value, P* addr, T compare_value);
+
+ template <DecoratorSet decorators, typename P, typename T>
+ T atomic_xchg(T new_value, P* addr);
+
+ template <DecoratorSet decorators, typename T>
+ bool arraycopy(arrayOop src_obj, arrayOop dst_obj, T *src, T *dst, size_t length);
+
+ template <DecoratorSet decorators>
+ void clone(oop src, oop dst, size_t size);
+
+ // Infer the type that should be returned from a load.
+ template <typename P, DecoratorSet decorators>
+ class LoadProxy: public StackObj {
+ private:
+ P *const _addr;
+ public:
+ LoadProxy(P* addr) : _addr(addr) {}
+
+ template <typename T>
+ inline operator T() {
+ return load<decorators, P, T>(_addr);
+ }
+
+ inline operator P() {
+ return load<decorators, P, P>(_addr);
+ }
+ };
+
+ // Infer the type that should be returned from a load_at.
+ template <DecoratorSet decorators>
+ class LoadAtProxy: public StackObj {
+ private:
+ const oop _base;
+ const ptrdiff_t _offset;
+ public:
+ LoadAtProxy(oop base, ptrdiff_t offset) : _base(base), _offset(offset) {}
+
+ template <typename T>
+ inline operator T() const {
+ return load_at<decorators, T>(_base, _offset);
+ }
+ };
+}
+
+template <DecoratorSet decorators = INTERNAL_EMPTY>
+class Access: public AllStatic {
+ // This function asserts that if an access gets passed in a decorator outside
+ // of the expected_decorators, then something is wrong. It additionally checks
+ // the consistency of the decorators so that supposedly disjoint decorators are indeed
+ // disjoint. For example, an access can not be both in heap and on root at the
+ // same time.
+ template <DecoratorSet expected_decorators>
+ static void verify_decorators();
+
+ 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 | MO_DECORATOR_MASK;
+ verify_decorators<expected_mo_decorators | primitive_decorators>();
+ }
+
+ template <DecoratorSet expected_mo_decorators>
+ static void verify_oop_decorators() {
+ const DecoratorSet oop_decorators = AS_DECORATOR_MASK | IN_DECORATOR_MASK |
+ (ON_DECORATOR_MASK ^ ON_UNKNOWN_OOP_REF) | // no unknown oop refs outside of the heap
+ OOP_DECORATOR_MASK | MO_DECORATOR_MASK;
+ verify_decorators<expected_mo_decorators | oop_decorators>();
+ }
+
+ template <DecoratorSet expected_mo_decorators>
+ static void verify_heap_oop_decorators() {
+ const DecoratorSet heap_oop_decorators = AS_DECORATOR_MASK | ON_DECORATOR_MASK |
+ OOP_DECORATOR_MASK | (IN_DECORATOR_MASK ^
+ (IN_ROOT ^ IN_CONCURRENT_ROOT)) | // no root accesses in the heap
+ MO_DECORATOR_MASK;
+ verify_decorators<expected_mo_decorators | heap_oop_decorators>();
+ }
+
+ static const DecoratorSet load_mo_decorators = MO_UNORDERED | MO_VOLATILE | MO_RELAXED | MO_ACQUIRE | MO_SEQ_CST;
+ static const DecoratorSet store_mo_decorators = MO_UNORDERED | MO_VOLATILE | MO_RELAXED | MO_RELEASE | MO_SEQ_CST;
+ static const DecoratorSet atomic_xchg_mo_decorators = MO_SEQ_CST;
+ static const DecoratorSet atomic_cmpxchg_mo_decorators = MO_RELAXED | MO_SEQ_CST;
+
+public:
+ // Primitive heap accesses
+ static inline AccessInternal::LoadAtProxy<decorators> load_at(oop base, ptrdiff_t offset) {
+ verify_primitive_decorators<load_mo_decorators>();
+ return AccessInternal::LoadAtProxy<decorators>(base, offset);
+ }
+
+ template <typename T>
+ static inline void store_at(oop base, ptrdiff_t offset, T value) {
+ verify_primitive_decorators<store_mo_decorators>();
+ AccessInternal::store_at<decorators>(base, offset, value);
+ }
+
+ template <typename T>
+ static inline T atomic_cmpxchg_at(T new_value, oop base, ptrdiff_t offset, T compare_value) {
+ verify_primitive_decorators<atomic_cmpxchg_mo_decorators>();
+ return AccessInternal::atomic_cmpxchg_at<decorators>(new_value, base, offset, compare_value);
+ }
+
+ template <typename T>
+ static inline T atomic_xchg_at(T new_value, oop base, ptrdiff_t offset) {
+ verify_primitive_decorators<atomic_xchg_mo_decorators>();
+ return AccessInternal::atomic_xchg_at<decorators>(new_value, base, offset);
+ }
+
+ template <typename T>
+ static inline bool arraycopy(arrayOop src_obj, arrayOop dst_obj, T *src, T *dst, size_t length) {
+ verify_decorators<ARRAYCOPY_DECORATOR_MASK | IN_HEAP |
+ AS_DECORATOR_MASK>();
+ return AccessInternal::arraycopy<decorators>(src_obj, dst_obj, src, dst, length);
+ }
+
+ // Oop heap accesses
+ static inline AccessInternal::LoadAtProxy<decorators | INTERNAL_VALUE_IS_OOP> oop_load_at(oop base, ptrdiff_t offset) {
+ verify_heap_oop_decorators<load_mo_decorators>();
+ return AccessInternal::LoadAtProxy<decorators | INTERNAL_VALUE_IS_OOP>(base, offset);
+ }
+
+ template <typename T>
+ static inline void oop_store_at(oop base, ptrdiff_t offset, T value) {
+ verify_heap_oop_decorators<store_mo_decorators>();
+ typedef typename AccessInternal::OopOrNarrowOop<T>::type OopType;
+ OopType oop_value = value;
+ AccessInternal::store_at<decorators | INTERNAL_VALUE_IS_OOP>(base, offset, oop_value);
+ }
+
+ template <typename T>
+ static inline T oop_atomic_cmpxchg_at(T new_value, oop base, ptrdiff_t offset, T compare_value) {
+ verify_heap_oop_decorators<atomic_cmpxchg_mo_decorators>();
+ typedef typename AccessInternal::OopOrNarrowOop<T>::type OopType;
+ OopType new_oop_value = new_value;
+ OopType compare_oop_value = compare_value;
+ return AccessInternal::atomic_cmpxchg_at<decorators | INTERNAL_VALUE_IS_OOP>(new_oop_value, base, offset, compare_oop_value);
+ }
+
+ template <typename T>
+ static inline T oop_atomic_xchg_at(T new_value, oop base, ptrdiff_t offset) {
+ verify_heap_oop_decorators<atomic_xchg_mo_decorators>();
+ typedef typename AccessInternal::OopOrNarrowOop<T>::type OopType;
+ OopType new_oop_value = new_value;
+ return AccessInternal::atomic_xchg_at<decorators | INTERNAL_VALUE_IS_OOP>(new_oop_value, base, offset);
+ }
+
+ template <typename T>
+ static inline bool oop_arraycopy(arrayOop src_obj, arrayOop dst_obj, T *src, T *dst, size_t length) {
+ verify_decorators<ARRAYCOPY_DECORATOR_MASK | IN_HEAP | AS_DECORATOR_MASK>();
+ return AccessInternal::arraycopy<decorators | INTERNAL_VALUE_IS_OOP>(src_obj, dst_obj, src, dst, length);
+ }
+
+ // Clone an object from src to dst
+ static inline void clone(oop src, oop dst, size_t size) {
+ verify_decorators<IN_HEAP>();
+ AccessInternal::clone<decorators>(src, dst, size);
+ }
+
+ // Primitive accesses
+ template <typename P>
+ static inline P load(P* addr) {
+ verify_primitive_decorators<load_mo_decorators>();
+ return AccessInternal::load<decorators, P, P>(addr);
+ }
+
+ template <typename P, typename T>
+ static inline void store(P* addr, T value) {
+ verify_primitive_decorators<store_mo_decorators>();
+ AccessInternal::store<decorators>(addr, value);
+ }
+
+ template <typename P, typename T>
+ static inline T atomic_cmpxchg(T new_value, P* addr, T compare_value) {
+ verify_primitive_decorators<atomic_cmpxchg_mo_decorators>();
+ return AccessInternal::atomic_cmpxchg<decorators>(new_value, addr, compare_value);
+ }
+
+ template <typename P, typename T>
+ static inline T atomic_xchg(T new_value, P* addr) {
+ verify_primitive_decorators<atomic_xchg_mo_decorators>();
+ return AccessInternal::atomic_xchg<decorators>(new_value, addr);
+ }
+
+ // Oop accesses
+ template <typename P>
+ static inline AccessInternal::LoadProxy<P, decorators | INTERNAL_VALUE_IS_OOP> oop_load(P* addr) {
+ verify_oop_decorators<load_mo_decorators>();
+ return AccessInternal::LoadProxy<P, decorators | INTERNAL_VALUE_IS_OOP>(addr);
+ }
+
+ template <typename P, typename T>
+ static inline void oop_store(P* addr, T value) {
+ verify_oop_decorators<store_mo_decorators>();
+ typedef typename AccessInternal::OopOrNarrowOop<T>::type OopType;
+ OopType oop_value = value;
+ AccessInternal::store<decorators | INTERNAL_VALUE_IS_OOP>(addr, oop_value);
+ }
+
+ template <typename P, typename T>
+ static inline T oop_atomic_cmpxchg(T new_value, P* addr, T compare_value) {
+ verify_oop_decorators<atomic_cmpxchg_mo_decorators>();
+ typedef typename AccessInternal::OopOrNarrowOop<T>::type OopType;
+ OopType new_oop_value = new_value;
+ OopType compare_oop_value = compare_value;
+ return AccessInternal::atomic_cmpxchg<decorators | INTERNAL_VALUE_IS_OOP>(new_oop_value, addr, compare_oop_value);
+ }
+
+ template <typename P, typename T>
+ static inline T oop_atomic_xchg(T new_value, P* addr) {
+ verify_oop_decorators<atomic_xchg_mo_decorators>();
+ typedef typename AccessInternal::OopOrNarrowOop<T>::type OopType;
+ OopType new_oop_value = new_value;
+ return AccessInternal::atomic_xchg<decorators | INTERNAL_VALUE_IS_OOP>(new_oop_value, addr);
+ }
+};
+
+// Helper for performing raw accesses (knows only of memory ordering
+// atomicity decorators as well as compressed oops)
+template <DecoratorSet decorators = INTERNAL_EMPTY>
+class RawAccess: public Access<AS_RAW | decorators> {};
+
+// Helper for performing normal accesses on the heap. These accesses
+// may resolve an accessor on a GC barrier set
+template <DecoratorSet decorators = INTERNAL_EMPTY>
+class HeapAccess: public Access<IN_HEAP | decorators> {};
+
+// Helper for performing normal accesses in roots. These accesses
+// may resolve an accessor on a GC barrier set
+template <DecoratorSet decorators = INTERNAL_EMPTY>
+class RootAccess: public Access<IN_ROOT | decorators> {};
+
+#endif // SHARE_VM_RUNTIME_ACCESS_HPP