jdk8-mips64-public/hotspot: src/share/vm/gc_implementation/g1/g1BiasedArray.hpp@595c0f60d50d (annotated)

src/share/vm/gc_implementation/g1/g1BiasedArray.hpp@595c0f60d50d (annotated)

src/share/vm/gc_implementation/g1/g1BiasedArray.hpp

Tue, 18 Mar 2014 19:07:22 +0100

author: pliden
date: Tue, 18 Mar 2014 19:07:22 +0100
changeset 6413: 595c0f60d50d
parent 6409: 5479cb006184
child 6680: 78bbf4d43a14
permissions: -rw-r--r--

8029075: String deduplication in G1
Summary: Implementation of JEP 192, http://openjdk.java.net/jeps/192
Reviewed-by: brutisso, tschatzl, coleenp

 /*
  * Copyright (c) 2013, 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_IMPLEMENTATION_G1_G1BIASEDARRAY_HPP
 #define SHARE_VM_GC_IMPLEMENTATION_G1_G1BIASEDARRAY_HPP
 #include "memory/allocation.hpp"
 #include "utilities/debug.hpp"
 // Implements the common base functionality for arrays that contain provisions
 // for accessing its elements using a biased index.
 // The element type is defined by the instantiating the template.
 class G1BiasedMappedArrayBase VALUE_OBJ_CLASS_SPEC {
   friend class VMStructs;
 public:
   typedef size_t idx_t;
 protected:
   address _base;          // the real base address
   size_t _length;         // the length of the array
   address _biased_base;   // base address biased by "bias" elements
   size_t _bias;           // the bias, i.e. the offset biased_base is located to the right in elements
   uint _shift_by;         // the amount of bits to shift right when mapping to an index of the array.
 protected:
   G1BiasedMappedArrayBase() : _base(NULL), _length(0), _biased_base(NULL),
     _bias(0), _shift_by(0) { }
   // Allocate a new array, generic version.
   static address create_new_base_array(size_t length, size_t elem_size);
   // Initialize the members of this class. The biased start address of this array
   // is the bias (in elements) multiplied by the element size.
   void initialize_base(address base, size_t length, size_t bias, size_t elem_size, uint shift_by) {
     assert(base != NULL, "just checking");
     assert(length > 0, "just checking");
     assert(shift_by < sizeof(uintptr_t) * 8, err_msg("Shifting by %zd, larger than word size?", shift_by));
     _base = base;
     _length = length;
     _biased_base = base - (bias * elem_size);
     _bias = bias;
     _shift_by = shift_by;
   }
   // Allocate and initialize this array to cover the heap addresses in the range
   // of [bottom, end).
   void initialize(HeapWord* bottom, HeapWord* end, size_t target_elem_size_in_bytes, size_t mapping_granularity_in_bytes) {
     assert(mapping_granularity_in_bytes > 0, "just checking");
     assert(is_power_of_2(mapping_granularity_in_bytes),
       err_msg("mapping granularity must be power of 2, is %zd", mapping_granularity_in_bytes));
     assert((uintptr_t)bottom % mapping_granularity_in_bytes == 0,
       err_msg("bottom mapping area address must be a multiple of mapping granularity %zd, is "PTR_FORMAT,
         mapping_granularity_in_bytes, bottom));
     assert((uintptr_t)end % mapping_granularity_in_bytes == 0,
       err_msg("end mapping area address must be a multiple of mapping granularity %zd, is "PTR_FORMAT,
         mapping_granularity_in_bytes, end));
     size_t num_target_elems = (end - bottom) / (mapping_granularity_in_bytes / HeapWordSize);
     idx_t bias = (uintptr_t)bottom / mapping_granularity_in_bytes;
     address base = create_new_base_array(num_target_elems, target_elem_size_in_bytes);
     initialize_base(base, num_target_elems, bias, target_elem_size_in_bytes, log2_intptr(mapping_granularity_in_bytes));
   }
   size_t bias() const { return _bias; }
   uint shift_by() const { return _shift_by; }
   void verify_index(idx_t index) const PRODUCT_RETURN;
   void verify_biased_index(idx_t biased_index) const PRODUCT_RETURN;
   void verify_biased_index_inclusive_end(idx_t biased_index) const PRODUCT_RETURN;
 public:
    // Return the length of the array in elements.
    size_t length() const { return _length; }
 };
 // Array that provides biased access and mapping from (valid) addresses in the
 // heap into this array.
 template<class T>
 class G1BiasedMappedArray : public G1BiasedMappedArrayBase {
 public:
   typedef G1BiasedMappedArrayBase::idx_t idx_t;
   T* base() const { return (T*)G1BiasedMappedArrayBase::_base; }
   // Return the element of the given array at the given index. Assume
   // the index is valid. This is a convenience method that does sanity
   // checking on the index.
   T get_by_index(idx_t index) const {
     verify_index(index);
     return this->base()[index];
   }
   // Set the element of the given array at the given index to the
   // given value. Assume the index is valid. This is a convenience
   // method that does sanity checking on the index.
   void set_by_index(idx_t index, T value) {
     verify_index(index);
     this->base()[index] = value;
   }
   // The raw biased base pointer.
   T* biased_base() const { return (T*)G1BiasedMappedArrayBase::_biased_base; }
   // Return the element of the given array that covers the given word in the
   // heap. Assumes the index is valid.
   T get_by_address(HeapWord* value) const {
     idx_t biased_index = ((uintptr_t)value) >> this->shift_by();
     this->verify_biased_index(biased_index);
     return biased_base()[biased_index];
   }
   // Set the value of the array entry that corresponds to the given array.
   void set_by_address(HeapWord * address, T value) {
     idx_t biased_index = ((uintptr_t)address) >> this->shift_by();
     this->verify_biased_index(biased_index);
     biased_base()[biased_index] = value;
   }
 protected:
   // Returns the address of the element the given address maps to
   T* address_mapped_to(HeapWord* address) {
     idx_t biased_index = ((uintptr_t)address) >> this->shift_by();
     this->verify_biased_index_inclusive_end(biased_index);
     return biased_base() + biased_index;
   }
 public:
   // Return the smallest address (inclusive) in the heap that this array covers.
   HeapWord* bottom_address_mapped() const {
     return (HeapWord*) ((uintptr_t)this->bias() << this->shift_by());
   }
   // Return the highest address (exclusive) in the heap that this array covers.
   HeapWord* end_address_mapped() const {
     return (HeapWord*) ((uintptr_t)(this->bias() + this->length()) << this->shift_by());
   }
 protected:
   virtual T default_value() const = 0;
   // Set all elements of the given array to the given value.
   void clear() {
     T value = default_value();
     for (idx_t i = 0; i < length(); i++) {
       set_by_index(i, value);
     }
   }
 public:
   G1BiasedMappedArray() {}
   // Allocate and initialize this array to cover the heap addresses in the range
   // of [bottom, end).
   void initialize(HeapWord* bottom, HeapWord* end, size_t mapping_granularity) {
     G1BiasedMappedArrayBase::initialize(bottom, end, sizeof(T), mapping_granularity);
     this->clear();
   }
 };
 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_G1BIASEDARRAY_HPP

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/gc_implementation/g1/g1BiasedArray.hpp@595c0f60d50d (annotated)

src/share/vm/gc_implementation/g1/g1BiasedArray.hpp