diff -r 000000000000 -r f90c822e73f8 src/share/vm/memory/barrierSet.hpp --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/share/vm/memory/barrierSet.hpp Wed Apr 27 01:25:04 2016 +0800 @@ -0,0 +1,187 @@ +/* + * Copyright (c) 2000, 2012, 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_MEMORY_BARRIERSET_HPP +#define SHARE_VM_MEMORY_BARRIERSET_HPP + +#include "memory/memRegion.hpp" +#include "oops/oopsHierarchy.hpp" + +// This class provides the interface between a barrier implementation and +// the rest of the system. + +class BarrierSet: public CHeapObj { + friend class VMStructs; +public: + enum Name { + ModRef, + CardTableModRef, + CardTableExtension, + G1SATBCT, + G1SATBCTLogging, + Other, + Uninit + }; + + enum Flags { + None = 0, + TargetUninitialized = 1 + }; +protected: + int _max_covered_regions; + Name _kind; + +public: + + BarrierSet() { _kind = Uninit; } + // To get around prohibition on RTTI. + BarrierSet::Name kind() { return _kind; } + virtual bool is_a(BarrierSet::Name bsn) = 0; + + // These operations indicate what kind of barriers the BarrierSet has. + virtual bool has_read_ref_barrier() = 0; + virtual bool has_read_prim_barrier() = 0; + virtual bool has_write_ref_barrier() = 0; + virtual bool has_write_ref_pre_barrier() = 0; + virtual bool has_write_prim_barrier() = 0; + + // These functions indicate whether a particular access of the given + // kinds requires a barrier. + virtual bool read_ref_needs_barrier(void* field) = 0; + virtual bool read_prim_needs_barrier(HeapWord* field, size_t bytes) = 0; + virtual bool write_prim_needs_barrier(HeapWord* field, size_t bytes, + juint val1, juint val2) = 0; + + // The first four operations provide a direct implementation of the + // barrier set. An interpreter loop, for example, could call these + // directly, as appropriate. + + // Invoke the barrier, if any, necessary when reading the given ref field. + virtual void read_ref_field(void* field) = 0; + + // Invoke the barrier, if any, necessary when reading the given primitive + // "field" of "bytes" bytes in "obj". + virtual void read_prim_field(HeapWord* field, size_t bytes) = 0; + + // Invoke the barrier, if any, necessary when writing "new_val" into the + // ref field at "offset" in "obj". + // (For efficiency reasons, this operation is specialized for certain + // barrier types. Semantically, it should be thought of as a call to the + // virtual "_work" function below, which must implement the barrier.) + // First the pre-write versions... + template inline void write_ref_field_pre(T* field, oop new_val); +private: + // Keep this private so as to catch violations at build time. + virtual void write_ref_field_pre_work( void* field, oop new_val) { guarantee(false, "Not needed"); }; +protected: + virtual void write_ref_field_pre_work( oop* field, oop new_val) {}; + virtual void write_ref_field_pre_work(narrowOop* field, oop new_val) {}; +public: + + // ...then the post-write version. + inline void write_ref_field(void* field, oop new_val, bool release = false); +protected: + virtual void write_ref_field_work(void* field, oop new_val, bool release = false) = 0; +public: + + // Invoke the barrier, if any, necessary when writing the "bytes"-byte + // value(s) "val1" (and "val2") into the primitive "field". + virtual void write_prim_field(HeapWord* field, size_t bytes, + juint val1, juint val2) = 0; + + // Operations on arrays, or general regions (e.g., for "clone") may be + // optimized by some barriers. + + // The first six operations tell whether such an optimization exists for + // the particular barrier. + virtual bool has_read_ref_array_opt() = 0; + virtual bool has_read_prim_array_opt() = 0; + virtual bool has_write_ref_array_pre_opt() { return true; } + virtual bool has_write_ref_array_opt() = 0; + virtual bool has_write_prim_array_opt() = 0; + + virtual bool has_read_region_opt() = 0; + virtual bool has_write_region_opt() = 0; + + // These operations should assert false unless the correponding operation + // above returns true. Otherwise, they should perform an appropriate + // barrier for an array whose elements are all in the given memory region. + virtual void read_ref_array(MemRegion mr) = 0; + virtual void read_prim_array(MemRegion mr) = 0; + + // Below length is the # array elements being written + virtual void write_ref_array_pre(oop* dst, int length, + bool dest_uninitialized = false) {} + virtual void write_ref_array_pre(narrowOop* dst, int length, + bool dest_uninitialized = false) {} + // Below count is the # array elements being written, starting + // at the address "start", which may not necessarily be HeapWord-aligned + inline void write_ref_array(HeapWord* start, size_t count); + + // Static versions, suitable for calling from generated code; + // count is # array elements being written, starting with "start", + // which may not necessarily be HeapWord-aligned. + static void static_write_ref_array_pre(HeapWord* start, size_t count); + static void static_write_ref_array_post(HeapWord* start, size_t count); + +protected: + virtual void write_ref_array_work(MemRegion mr) = 0; +public: + virtual void write_prim_array(MemRegion mr) = 0; + + virtual void read_region(MemRegion mr) = 0; + + // (For efficiency reasons, this operation is specialized for certain + // barrier types. Semantically, it should be thought of as a call to the + // virtual "_work" function below, which must implement the barrier.) + inline void write_region(MemRegion mr); +protected: + virtual void write_region_work(MemRegion mr) = 0; +public: + + // Some barrier sets create tables whose elements correspond to parts of + // the heap; the CardTableModRefBS is an example. Such barrier sets will + // normally reserve space for such tables, and commit parts of the table + // "covering" parts of the heap that are committed. The constructor is + // passed the maximum number of independently committable subregions to + // be covered, and the "resize_covoered_region" function allows the + // sub-parts of the heap to inform the barrier set of changes of their + // sizes. + BarrierSet(int max_covered_regions) : + _max_covered_regions(max_covered_regions) {} + + // Inform the BarrierSet that the the covered heap region that starts + // with "base" has been changed to have the given size (possibly from 0, + // for initialization.) + virtual void resize_covered_region(MemRegion new_region) = 0; + + // If the barrier set imposes any alignment restrictions on boundaries + // within the heap, this function tells whether they are met. + virtual bool is_aligned(HeapWord* addr) = 0; + + // Print a description of the memory for the barrier set + virtual void print_on(outputStream* st) const = 0; +}; + +#endif // SHARE_VM_MEMORY_BARRIERSET_HPP