1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/src/share/vm/memory/barrierSet.hpp Wed Apr 27 01:25:04 2016 +0800
1.3 @@ -0,0 +1,187 @@
1.4 +/*
1.5 + * Copyright (c) 2000, 2012, Oracle and/or its affiliates. All rights reserved.
1.6 + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
1.7 + *
1.8 + * This code is free software; you can redistribute it and/or modify it
1.9 + * under the terms of the GNU General Public License version 2 only, as
1.10 + * published by the Free Software Foundation.
1.11 + *
1.12 + * This code is distributed in the hope that it will be useful, but WITHOUT
1.13 + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
1.14 + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
1.15 + * version 2 for more details (a copy is included in the LICENSE file that
1.16 + * accompanied this code).
1.17 + *
1.18 + * You should have received a copy of the GNU General Public License version
1.19 + * 2 along with this work; if not, write to the Free Software Foundation,
1.20 + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
1.21 + *
1.22 + * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
1.23 + * or visit www.oracle.com if you need additional information or have any
1.24 + * questions.
1.25 + *
1.26 + */
1.27 +
1.28 +#ifndef SHARE_VM_MEMORY_BARRIERSET_HPP
1.29 +#define SHARE_VM_MEMORY_BARRIERSET_HPP
1.30 +
1.31 +#include "memory/memRegion.hpp"
1.32 +#include "oops/oopsHierarchy.hpp"
1.33 +
1.34 +// This class provides the interface between a barrier implementation and
1.35 +// the rest of the system.
1.36 +
1.37 +class BarrierSet: public CHeapObj<mtGC> {
1.38 + friend class VMStructs;
1.39 +public:
1.40 + enum Name {
1.41 + ModRef,
1.42 + CardTableModRef,
1.43 + CardTableExtension,
1.44 + G1SATBCT,
1.45 + G1SATBCTLogging,
1.46 + Other,
1.47 + Uninit
1.48 + };
1.49 +
1.50 + enum Flags {
1.51 + None = 0,
1.52 + TargetUninitialized = 1
1.53 + };
1.54 +protected:
1.55 + int _max_covered_regions;
1.56 + Name _kind;
1.57 +
1.58 +public:
1.59 +
1.60 + BarrierSet() { _kind = Uninit; }
1.61 + // To get around prohibition on RTTI.
1.62 + BarrierSet::Name kind() { return _kind; }
1.63 + virtual bool is_a(BarrierSet::Name bsn) = 0;
1.64 +
1.65 + // These operations indicate what kind of barriers the BarrierSet has.
1.66 + virtual bool has_read_ref_barrier() = 0;
1.67 + virtual bool has_read_prim_barrier() = 0;
1.68 + virtual bool has_write_ref_barrier() = 0;
1.69 + virtual bool has_write_ref_pre_barrier() = 0;
1.70 + virtual bool has_write_prim_barrier() = 0;
1.71 +
1.72 + // These functions indicate whether a particular access of the given
1.73 + // kinds requires a barrier.
1.74 + virtual bool read_ref_needs_barrier(void* field) = 0;
1.75 + virtual bool read_prim_needs_barrier(HeapWord* field, size_t bytes) = 0;
1.76 + virtual bool write_prim_needs_barrier(HeapWord* field, size_t bytes,
1.77 + juint val1, juint val2) = 0;
1.78 +
1.79 + // The first four operations provide a direct implementation of the
1.80 + // barrier set. An interpreter loop, for example, could call these
1.81 + // directly, as appropriate.
1.82 +
1.83 + // Invoke the barrier, if any, necessary when reading the given ref field.
1.84 + virtual void read_ref_field(void* field) = 0;
1.85 +
1.86 + // Invoke the barrier, if any, necessary when reading the given primitive
1.87 + // "field" of "bytes" bytes in "obj".
1.88 + virtual void read_prim_field(HeapWord* field, size_t bytes) = 0;
1.89 +
1.90 + // Invoke the barrier, if any, necessary when writing "new_val" into the
1.91 + // ref field at "offset" in "obj".
1.92 + // (For efficiency reasons, this operation is specialized for certain
1.93 + // barrier types. Semantically, it should be thought of as a call to the
1.94 + // virtual "_work" function below, which must implement the barrier.)
1.95 + // First the pre-write versions...
1.96 + template <class T> inline void write_ref_field_pre(T* field, oop new_val);
1.97 +private:
1.98 + // Keep this private so as to catch violations at build time.
1.99 + virtual void write_ref_field_pre_work( void* field, oop new_val) { guarantee(false, "Not needed"); };
1.100 +protected:
1.101 + virtual void write_ref_field_pre_work( oop* field, oop new_val) {};
1.102 + virtual void write_ref_field_pre_work(narrowOop* field, oop new_val) {};
1.103 +public:
1.104 +
1.105 + // ...then the post-write version.
1.106 + inline void write_ref_field(void* field, oop new_val, bool release = false);
1.107 +protected:
1.108 + virtual void write_ref_field_work(void* field, oop new_val, bool release = false) = 0;
1.109 +public:
1.110 +
1.111 + // Invoke the barrier, if any, necessary when writing the "bytes"-byte
1.112 + // value(s) "val1" (and "val2") into the primitive "field".
1.113 + virtual void write_prim_field(HeapWord* field, size_t bytes,
1.114 + juint val1, juint val2) = 0;
1.115 +
1.116 + // Operations on arrays, or general regions (e.g., for "clone") may be
1.117 + // optimized by some barriers.
1.118 +
1.119 + // The first six operations tell whether such an optimization exists for
1.120 + // the particular barrier.
1.121 + virtual bool has_read_ref_array_opt() = 0;
1.122 + virtual bool has_read_prim_array_opt() = 0;
1.123 + virtual bool has_write_ref_array_pre_opt() { return true; }
1.124 + virtual bool has_write_ref_array_opt() = 0;
1.125 + virtual bool has_write_prim_array_opt() = 0;
1.126 +
1.127 + virtual bool has_read_region_opt() = 0;
1.128 + virtual bool has_write_region_opt() = 0;
1.129 +
1.130 + // These operations should assert false unless the correponding operation
1.131 + // above returns true. Otherwise, they should perform an appropriate
1.132 + // barrier for an array whose elements are all in the given memory region.
1.133 + virtual void read_ref_array(MemRegion mr) = 0;
1.134 + virtual void read_prim_array(MemRegion mr) = 0;
1.135 +
1.136 + // Below length is the # array elements being written
1.137 + virtual void write_ref_array_pre(oop* dst, int length,
1.138 + bool dest_uninitialized = false) {}
1.139 + virtual void write_ref_array_pre(narrowOop* dst, int length,
1.140 + bool dest_uninitialized = false) {}
1.141 + // Below count is the # array elements being written, starting
1.142 + // at the address "start", which may not necessarily be HeapWord-aligned
1.143 + inline void write_ref_array(HeapWord* start, size_t count);
1.144 +
1.145 + // Static versions, suitable for calling from generated code;
1.146 + // count is # array elements being written, starting with "start",
1.147 + // which may not necessarily be HeapWord-aligned.
1.148 + static void static_write_ref_array_pre(HeapWord* start, size_t count);
1.149 + static void static_write_ref_array_post(HeapWord* start, size_t count);
1.150 +
1.151 +protected:
1.152 + virtual void write_ref_array_work(MemRegion mr) = 0;
1.153 +public:
1.154 + virtual void write_prim_array(MemRegion mr) = 0;
1.155 +
1.156 + virtual void read_region(MemRegion mr) = 0;
1.157 +
1.158 + // (For efficiency reasons, this operation is specialized for certain
1.159 + // barrier types. Semantically, it should be thought of as a call to the
1.160 + // virtual "_work" function below, which must implement the barrier.)
1.161 + inline void write_region(MemRegion mr);
1.162 +protected:
1.163 + virtual void write_region_work(MemRegion mr) = 0;
1.164 +public:
1.165 +
1.166 + // Some barrier sets create tables whose elements correspond to parts of
1.167 + // the heap; the CardTableModRefBS is an example. Such barrier sets will
1.168 + // normally reserve space for such tables, and commit parts of the table
1.169 + // "covering" parts of the heap that are committed. The constructor is
1.170 + // passed the maximum number of independently committable subregions to
1.171 + // be covered, and the "resize_covoered_region" function allows the
1.172 + // sub-parts of the heap to inform the barrier set of changes of their
1.173 + // sizes.
1.174 + BarrierSet(int max_covered_regions) :
1.175 + _max_covered_regions(max_covered_regions) {}
1.176 +
1.177 + // Inform the BarrierSet that the the covered heap region that starts
1.178 + // with "base" has been changed to have the given size (possibly from 0,
1.179 + // for initialization.)
1.180 + virtual void resize_covered_region(MemRegion new_region) = 0;
1.181 +
1.182 + // If the barrier set imposes any alignment restrictions on boundaries
1.183 + // within the heap, this function tells whether they are met.
1.184 + virtual bool is_aligned(HeapWord* addr) = 0;
1.185 +
1.186 + // Print a description of the memory for the barrier set
1.187 + virtual void print_on(outputStream* st) const = 0;
1.188 +};
1.189 +
1.190 +#endif // SHARE_VM_MEMORY_BARRIERSET_HPP
