author | xdono |
Wed, 02 Jul 2008 12:55:16 -0700 | |
changeset 670 | ddf3e9583f2f |
parent 360 | 21d113ecbf6a |
child 1388 | 3677f5f3d66b |
permissions | -rw-r--r-- |
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/* |
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* Copyright 2000-2008 Sun Microsystems, Inc. All Rights Reserved. |
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
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* |
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* This code is free software; you can redistribute it and/or modify it |
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* under the terms of the GNU General Public License version 2 only, as |
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* published by the Free Software Foundation. |
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* |
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* This code is distributed in the hope that it will be useful, but WITHOUT |
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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* version 2 for more details (a copy is included in the LICENSE file that |
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* accompanied this code). |
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* |
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* You should have received a copy of the GNU General Public License version |
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* 2 along with this work; if not, write to the Free Software Foundation, |
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
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* |
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* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
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* CA 95054 USA or visit www.sun.com if you need additional information or |
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* have any questions. |
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* |
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*/ |
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// This class provides the interface between a barrier implementation and |
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// the rest of the system. |
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class BarrierSet: public CHeapObj { |
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friend class VMStructs; |
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public: |
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enum Name { |
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ModRef, |
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CardTableModRef, |
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CardTableExtension, |
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Other, |
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Uninit |
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}; |
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protected: |
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int _max_covered_regions; |
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Name _kind; |
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public: |
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// To get around prohibition on RTTI. |
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virtual BarrierSet::Name kind() { return _kind; } |
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virtual bool is_a(BarrierSet::Name bsn) = 0; |
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// These operations indicate what kind of barriers the BarrierSet has. |
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virtual bool has_read_ref_barrier() = 0; |
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virtual bool has_read_prim_barrier() = 0; |
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virtual bool has_write_ref_barrier() = 0; |
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virtual bool has_write_prim_barrier() = 0; |
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// These functions indicate whether a particular access of the given |
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// kinds requires a barrier. |
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virtual bool read_ref_needs_barrier(void* field) = 0; |
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virtual bool read_prim_needs_barrier(HeapWord* field, size_t bytes) = 0; |
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virtual bool write_ref_needs_barrier(void* field, oop new_val) = 0; |
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virtual bool write_prim_needs_barrier(HeapWord* field, size_t bytes, juint val1, juint val2) = 0; |
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// The first four operations provide a direct implementation of the |
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// barrier set. An interpreter loop, for example, could call these |
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// directly, as appropriate. |
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// Invoke the barrier, if any, necessary when reading the given ref field. |
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coleenp
parents:
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virtual void read_ref_field(void* field) = 0; |
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// Invoke the barrier, if any, necessary when reading the given primitive |
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// "field" of "bytes" bytes in "obj". |
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virtual void read_prim_field(HeapWord* field, size_t bytes) = 0; |
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// Invoke the barrier, if any, necessary when writing "new_val" into the |
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// ref field at "offset" in "obj". |
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// (For efficiency reasons, this operation is specialized for certain |
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// barrier types. Semantically, it should be thought of as a call to the |
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// virtual "_work" function below, which must implement the barrier.) |
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inline void write_ref_field(void* field, oop new_val); |
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protected: |
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virtual void write_ref_field_work(void* field, oop new_val) = 0; |
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public: |
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// Invoke the barrier, if any, necessary when writing the "bytes"-byte |
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// value(s) "val1" (and "val2") into the primitive "field". |
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virtual void write_prim_field(HeapWord* field, size_t bytes, |
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juint val1, juint val2) = 0; |
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// Operations on arrays, or general regions (e.g., for "clone") may be |
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// optimized by some barriers. |
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// The first six operations tell whether such an optimization exists for |
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// the particular barrier. |
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virtual bool has_read_ref_array_opt() = 0; |
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virtual bool has_read_prim_array_opt() = 0; |
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virtual bool has_write_ref_array_opt() = 0; |
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virtual bool has_write_prim_array_opt() = 0; |
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virtual bool has_read_region_opt() = 0; |
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virtual bool has_write_region_opt() = 0; |
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// These operations should assert false unless the correponding operation |
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// above returns true. Otherwise, they should perform an appropriate |
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// barrier for an array whose elements are all in the given memory region. |
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virtual void read_ref_array(MemRegion mr) = 0; |
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virtual void read_prim_array(MemRegion mr) = 0; |
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inline void write_ref_array(MemRegion mr); |
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protected: |
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virtual void write_ref_array_work(MemRegion mr) = 0; |
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public: |
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virtual void write_prim_array(MemRegion mr) = 0; |
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virtual void read_region(MemRegion mr) = 0; |
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// (For efficiency reasons, this operation is specialized for certain |
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// barrier types. Semantically, it should be thought of as a call to the |
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// virtual "_work" function below, which must implement the barrier.) |
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inline void write_region(MemRegion mr); |
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protected: |
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virtual void write_region_work(MemRegion mr) = 0; |
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public: |
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// The remaining sets of operations are called by compilers or other code |
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// generators to insert barriers into generated code. There may be |
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// several such code generators; the signatures of these |
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// barrier-generating functions may differ from generator to generator. |
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// There will be a set of four function signatures for each code |
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// generator, which accomplish the generation of barriers of the four |
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// kinds listed above. |
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#ifdef TBD |
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// Generates code to invoke the barrier, if any, necessary when reading |
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// the ref field at "offset" in "obj". |
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virtual void gen_read_ref_field() = 0; |
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// Generates code to invoke the barrier, if any, necessary when reading |
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// the primitive field of "bytes" bytes at offset" in "obj". |
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virtual void gen_read_prim_field() = 0; |
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// Generates code to invoke the barrier, if any, necessary when writing |
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// "new_val" into the ref field at "offset" in "obj". |
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virtual void gen_write_ref_field() = 0; |
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// Generates code to invoke the barrier, if any, necessary when writing |
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// the "bytes"-byte value "new_val" into the primitive field at "offset" |
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// in "obj". |
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virtual void gen_write_prim_field() = 0; |
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#endif |
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// Some barrier sets create tables whose elements correspond to parts of |
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// the heap; the CardTableModRefBS is an example. Such barrier sets will |
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// normally reserve space for such tables, and commit parts of the table |
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// "covering" parts of the heap that are committed. The constructor is |
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// passed the maximum number of independently committable subregions to |
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// be covered, and the "resize_covoered_region" function allows the |
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// sub-parts of the heap to inform the barrier set of changes of their |
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// sizes. |
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BarrierSet(int max_covered_regions) : |
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_max_covered_regions(max_covered_regions) {} |
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// Inform the BarrierSet that the the covered heap region that starts |
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// with "base" has been changed to have the given size (possibly from 0, |
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// for initialization.) |
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virtual void resize_covered_region(MemRegion new_region) = 0; |
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// If the barrier set imposes any alignment restrictions on boundaries |
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// within the heap, this function tells whether they are met. |
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virtual bool is_aligned(HeapWord* addr) = 0; |
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}; |