| /* |
| * 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 |
| * 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_OOPS_ACCESS_HPP |
| #define SHARE_OOPS_ACCESS_HPP |
| |
| #include "memory/allocation.hpp" |
| #include "oops/accessBackend.hpp" |
| #include "oops/accessDecorators.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. For more information about what |
| // decorators are available, cf. oops/accessDecorators.hpp. |
| // 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. The ArrayAccess class has convenience functions for this. |
| // * clone: Clone the contents of an object to a newly allocated object. |
| // * resolve: Resolve a stable to-space invariant oop that is guaranteed not to relocate its payload until a subsequent thread transition. |
| // |
| // == IMPLEMENTATION == |
| // Each access goes through the following steps in a template pipeline. |
| // There are essentially 5 steps for each access: |
| // * Step 1: Set default decorators and decay types. This step gets rid of CV qualifiers |
| // and sets default decorators to sensible values. |
| // * Step 2: Reduce types. This step makes sure there is only a single T type and not |
| // multiple types. The P type of the address and T type of the value must |
| // match. |
| // * Step 3: Pre-runtime dispatch. This step checks whether a runtime call can be |
| // avoided, and in that case avoids it (calling raw accesses or |
| // primitive accesses in a build that does not require primitive GC barriers) |
| // * Step 4: Runtime-dispatch. This step performs a runtime dispatch to the corresponding |
| // BarrierSet::AccessBarrier accessor that attaches GC-required barriers |
| // to the access. |
| // * Step 5.a: Barrier resolution. This step is invoked the first time a runtime-dispatch |
| // happens for an access. The appropriate BarrierSet::AccessBarrier accessor |
| // is resolved, then the function pointer is updated to that accessor for |
| // future invocations. |
| // * Step 5.b: Post-runtime dispatch. This step now casts previously unknown types such |
| // as the address type of an oop on the heap (is it oop* or narrowOop*) to |
| // the appropriate type. It also splits sufficiently orthogonal accesses into |
| // different functions, such as whether the access involves oops or primitives |
| // and whether the access is performed on the heap or outside. Then the |
| // appropriate BarrierSet::AccessBarrier is called to perform the access. |
| // |
| // The implementation of step 1-4 resides in in accessBackend.hpp, to allow selected |
| // accesses to be accessible from only access.hpp, as opposed to access.inline.hpp. |
| // Steps 5.a and 5.b require knowledge about the GC backends, and therefore needs to |
| // include the various GC backend .inline.hpp headers. Their implementation resides in |
| // access.inline.hpp. The accesses that are allowed through the access.hpp file |
| // must be instantiated in access.cpp using the INSTANTIATE_HPP_ACCESS macro. |
| |
| 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 | IS_ARRAY; |
| 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 |
| IS_ARRAY | IS_NOT_NULL | IS_DEST_UNINITIALIZED; |
| 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 | |
| IN_HEAP | IS_ARRAY | IS_NOT_NULL; |
| 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; |
| |
| protected: |
| template <typename T> |
| static inline bool oop_arraycopy(arrayOop src_obj, size_t src_offset_in_bytes, const T* src_raw, |
| arrayOop dst_obj, size_t dst_offset_in_bytes, T* dst_raw, |
| size_t length) { |
| verify_decorators<ARRAYCOPY_DECORATOR_MASK | IN_HEAP | |
| AS_DECORATOR_MASK | IS_ARRAY | IS_DEST_UNINITIALIZED>(); |
| return AccessInternal::arraycopy<decorators | INTERNAL_VALUE_IS_OOP>(src_obj, src_offset_in_bytes, src_raw, |
| dst_obj, dst_offset_in_bytes, dst_raw, |
| length); |
| } |
| |
| template <typename T> |
| static inline void arraycopy(arrayOop src_obj, size_t src_offset_in_bytes, const T* src_raw, |
| arrayOop dst_obj, size_t dst_offset_in_bytes, T* dst_raw, |
| size_t length) { |
| verify_decorators<ARRAYCOPY_DECORATOR_MASK | IN_HEAP | |
| AS_DECORATOR_MASK | IS_ARRAY>(); |
| AccessInternal::arraycopy<decorators>(src_obj, src_offset_in_bytes, src_raw, |
| dst_obj, dst_offset_in_bytes, dst_raw, |
| length); |
| } |
| |
| 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); |
| } |
| |
| // Oop heap accesses |
| static inline AccessInternal::OopLoadAtProxy<decorators> oop_load_at(oop base, ptrdiff_t offset) { |
| verify_heap_oop_decorators<load_mo_decorators>(); |
| return AccessInternal::OopLoadAtProxy<decorators>(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); |
| } |
| |
| // 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::OopLoadProxy<P, decorators> oop_load(P* addr) { |
| verify_oop_decorators<load_mo_decorators>(); |
| return AccessInternal::OopLoadProxy<P, decorators>(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); |
| } |
| |
| static oop resolve(oop obj) { |
| verify_decorators<INTERNAL_EMPTY>(); |
| return AccessInternal::resolve<decorators>(obj); |
| } |
| }; |
| |
| // 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 NativeAccess: public Access<IN_NATIVE | decorators> {}; |
| |
| // Helper for array access. |
| template <DecoratorSet decorators = INTERNAL_EMPTY> |
| class ArrayAccess: public HeapAccess<IS_ARRAY | decorators> { |
| typedef HeapAccess<IS_ARRAY | decorators> AccessT; |
| public: |
| template <typename T> |
| static inline void arraycopy(arrayOop src_obj, size_t src_offset_in_bytes, |
| arrayOop dst_obj, size_t dst_offset_in_bytes, |
| size_t length) { |
| AccessT::arraycopy(src_obj, src_offset_in_bytes, reinterpret_cast<const T*>(NULL), |
| dst_obj, dst_offset_in_bytes, reinterpret_cast<T*>(NULL), |
| length); |
| } |
| |
| template <typename T> |
| static inline void arraycopy_to_native(arrayOop src_obj, size_t src_offset_in_bytes, |
| T* dst, |
| size_t length) { |
| AccessT::arraycopy(src_obj, src_offset_in_bytes, reinterpret_cast<const T*>(NULL), |
| NULL, 0, dst, |
| length); |
| } |
| |
| template <typename T> |
| static inline void arraycopy_from_native(const T* src, |
| arrayOop dst_obj, size_t dst_offset_in_bytes, |
| size_t length) { |
| AccessT::arraycopy(NULL, 0, src, |
| dst_obj, dst_offset_in_bytes, reinterpret_cast<T*>(NULL), |
| length); |
| } |
| |
| static inline bool oop_arraycopy(arrayOop src_obj, size_t src_offset_in_bytes, |
| arrayOop dst_obj, size_t dst_offset_in_bytes, |
| size_t length) { |
| return AccessT::oop_arraycopy(src_obj, src_offset_in_bytes, reinterpret_cast<const HeapWord*>(NULL), |
| dst_obj, dst_offset_in_bytes, reinterpret_cast<HeapWord*>(NULL), |
| length); |
| } |
| |
| template <typename T> |
| static inline bool oop_arraycopy_raw(T* src, T* dst, size_t length) { |
| return AccessT::oop_arraycopy(NULL, 0, src, |
| NULL, 0, dst, |
| length); |
| } |
| |
| }; |
| |
| template <DecoratorSet decorators> |
| template <DecoratorSet expected_decorators> |
| void Access<decorators>::verify_decorators() { |
| STATIC_ASSERT((~expected_decorators & decorators) == 0); // unexpected decorator used |
| 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_RAW) == 0 || |
| (barrier_strength_decorators ^ AS_NORMAL) == 0 |
| )); |
| const DecoratorSet ref_strength_decorators = decorators & ON_DECORATOR_MASK; |
| STATIC_ASSERT(ref_strength_decorators == 0 || ( // make sure ref strength decorators are disjoint if set |
| (ref_strength_decorators ^ ON_STRONG_OOP_REF) == 0 || |
| (ref_strength_decorators ^ ON_WEAK_OOP_REF) == 0 || |
| (ref_strength_decorators ^ ON_PHANTOM_OOP_REF) == 0 || |
| (ref_strength_decorators ^ ON_UNKNOWN_OOP_REF) == 0 |
| )); |
| const DecoratorSet memory_ordering_decorators = decorators & MO_DECORATOR_MASK; |
| STATIC_ASSERT(memory_ordering_decorators == 0 || ( // make sure memory ordering decorators are disjoint if set |
| (memory_ordering_decorators ^ MO_UNORDERED) == 0 || |
| (memory_ordering_decorators ^ MO_VOLATILE) == 0 || |
| (memory_ordering_decorators ^ MO_RELAXED) == 0 || |
| (memory_ordering_decorators ^ MO_ACQUIRE) == 0 || |
| (memory_ordering_decorators ^ MO_RELEASE) == 0 || |
| (memory_ordering_decorators ^ MO_SEQ_CST) == 0 |
| )); |
| 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 |
| )); |
| } |
| |
| #endif // SHARE_OOPS_ACCESS_HPP |