--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/src/share/vm/gc/shared/barrierSet.hpp Wed May 13 15:16:06 2015 +0200
@@ -0,0 +1,221 @@
+/*
+ * Copyright (c) 2000, 2015, 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_GC_SHARED_BARRIERSET_HPP
+#define SHARE_VM_GC_SHARED_BARRIERSET_HPP
+
+#include "memory/memRegion.hpp"
+#include "oops/oopsHierarchy.hpp"
+#include "utilities/fakeRttiSupport.hpp"
+
+// This class provides the interface between a barrier implementation and
+// the rest of the system.
+
+class BarrierSet: public CHeapObj<mtGC> {
+ friend class VMStructs;
+public:
+ // Fake RTTI support. For a derived class T to participate
+ // - T must have a corresponding Name entry.
+ // - GetName<T> must be specialized to return the corresponding Name
+ // entry.
+ // - If T is a base class, the constructor must have a FakeRtti
+ // parameter and pass it up to its base class, with the tag set
+ // augmented with the corresponding Name entry.
+ // - If T is a concrete class, the constructor must create a
+ // FakeRtti object whose tag set includes the corresponding Name
+ // entry, and pass it up to its base class.
+
+ enum Name { // associated class
+ ModRef, // ModRefBarrierSet
+ CardTableModRef, // CardTableModRefBS
+ CardTableForRS, // CardTableModRefBSForCTRS
+ CardTableExtension, // CardTableExtension
+ G1SATBCT, // G1SATBCardTableModRefBS
+ G1SATBCTLogging // G1SATBCardTableLoggingModRefBS
+ };
+
+protected:
+ typedef FakeRttiSupport<BarrierSet, Name> FakeRtti;
+
+private:
+ FakeRtti _fake_rtti;
+
+ // Metafunction mapping a class derived from BarrierSet to the
+ // corresponding Name enum tag.
+ template<typename T> struct GetName;
+
+ // Downcast argument to a derived barrier set type.
+ // The cast is checked in a debug build.
+ // T must have a specialization for BarrierSet::GetName<T>.
+ template<typename T> friend T* barrier_set_cast(BarrierSet* bs);
+
+public:
+ // Note: This is not presently the Name corresponding to the
+ // concrete class of this object.
+ BarrierSet::Name kind() const { return _fake_rtti.concrete_tag(); }
+
+ // Test whether this object is of the type corresponding to bsn.
+ bool is_a(BarrierSet::Name bsn) const { return _fake_rtti.has_tag(bsn); }
+
+ // End of fake RTTI support.
+
+public:
+ enum Flags {
+ None = 0,
+ TargetUninitialized = 1
+ };
+
+protected:
+ // 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. At most one covered
+ // region per generation is needed.
+ static const int _max_covered_regions = 2;
+
+ BarrierSet(const FakeRtti& fake_rtti) : _fake_rtti(fake_rtti) { }
+ ~BarrierSet() { }
+
+public:
+
+ // 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 <class T> 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 corresponding 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.)
+ void write_region(MemRegion mr);
+protected:
+ virtual void write_region_work(MemRegion mr) = 0;
+public:
+ // 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;
+};
+
+template<typename T>
+inline T* barrier_set_cast(BarrierSet* bs) {
+ assert(bs->is_a(BarrierSet::GetName<T>::value), "wrong type of barrier set");
+ return static_cast<T*>(bs);
+}
+
+#endif // SHARE_VM_GC_SHARED_BARRIERSET_HPP