8079792: GC directory structure cleanup

Reviewed-by: brutisso, stefank, david

hotspot/src/share/vm/gc/shared/barrierSet.hpp

@@ -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