Mercurial > hg > truffle
diff src/share/vm/memory/barrierSet.hpp @ 0:a61af66fc99e jdk7-b24
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author | duke |
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date | Sat, 01 Dec 2007 00:00:00 +0000 |
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children | ba764ed4b6f2 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/share/vm/memory/barrierSet.hpp Sat Dec 01 00:00:00 2007 +0000 @@ -0,0 +1,170 @@ +/* + * Copyright 2000-2002 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, + * CA 95054 USA or visit www.sun.com if you need additional information or + * have any questions. + * + */ + +// 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, + Other, + Uninit + }; + +protected: + int _max_covered_regions; + Name _kind; + +public: + + // To get around prohibition on RTTI. + virtual 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_prim_barrier() = 0; + + // These functions indicate whether a particular access of the given + // kinds requires a barrier. + virtual bool read_ref_needs_barrier(oop* field) = 0; + virtual bool read_prim_needs_barrier(HeapWord* field, size_t bytes) = 0; + virtual bool write_ref_needs_barrier(oop* field, oop new_val) = 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(oop* 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.) + inline void write_ref_field(oop* field, oop new_val); +protected: + virtual void write_ref_field_work(oop* field, oop new_val) = 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_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; + + inline void write_ref_array(MemRegion mr); +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: + + // The remaining sets of operations are called by compilers or other code + // generators to insert barriers into generated code. There may be + // several such code generators; the signatures of these + // barrier-generating functions may differ from generator to generator. + // There will be a set of four function signatures for each code + // generator, which accomplish the generation of barriers of the four + // kinds listed above. + +#ifdef TBD + // Generates code to invoke the barrier, if any, necessary when reading + // the ref field at "offset" in "obj". + virtual void gen_read_ref_field() = 0; + + // Generates code to invoke the barrier, if any, necessary when reading + // the primitive field of "bytes" bytes at offset" in "obj". + virtual void gen_read_prim_field() = 0; + + // Generates code to invoke the barrier, if any, necessary when writing + // "new_val" into the ref field at "offset" in "obj". + virtual void gen_write_ref_field() = 0; + + // Generates code to invoke the barrier, if any, necessary when writing + // the "bytes"-byte value "new_val" into the primitive field at "offset" + // in "obj". + virtual void gen_write_prim_field() = 0; +#endif + + // 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; + +};