aoqi@0: /*
aoqi@0:  * Copyright (c) 2013, 2014, Oracle and/or its affiliates. All rights reserved.
aoqi@0:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
aoqi@0:  *
aoqi@0:  * This code is free software; you can redistribute it and/or modify it
aoqi@0:  * under the terms of the GNU General Public License version 2 only, as
aoqi@0:  * published by the Free Software Foundation.
aoqi@0:  *
aoqi@0:  * This code is distributed in the hope that it will be useful, but WITHOUT
aoqi@0:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
aoqi@0:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
aoqi@0:  * version 2 for more details (a copy is included in the LICENSE file that
aoqi@0:  * accompanied this code).
aoqi@0:  *
aoqi@0:  * You should have received a copy of the GNU General Public License version
aoqi@0:  * 2 along with this work; if not, write to the Free Software Foundation,
aoqi@0:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
aoqi@0:  *
aoqi@0:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
aoqi@0:  * or visit www.oracle.com if you need additional information or have any
aoqi@0:  * questions.
aoqi@0:  *
aoqi@0:  */
aoqi@0: 
aoqi@0: #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_G1BIASEDARRAY_HPP
aoqi@0: #define SHARE_VM_GC_IMPLEMENTATION_G1_G1BIASEDARRAY_HPP
aoqi@0: 
aoqi@0: #include "memory/allocation.hpp"
aoqi@0: #include "utilities/debug.hpp"
aoqi@0: 
aoqi@0: // Implements the common base functionality for arrays that contain provisions
aoqi@0: // for accessing its elements using a biased index.
aoqi@0: // The element type is defined by the instantiating the template.
aoqi@0: class G1BiasedMappedArrayBase VALUE_OBJ_CLASS_SPEC {
aoqi@0:   friend class VMStructs;
aoqi@0: public:
aoqi@0:   typedef size_t idx_t;
aoqi@0: protected:
aoqi@0:   address _base;          // the real base address
aoqi@0:   size_t _length;         // the length of the array
aoqi@0:   address _biased_base;   // base address biased by "bias" elements
aoqi@0:   size_t _bias;           // the bias, i.e. the offset biased_base is located to the right in elements
aoqi@0:   uint _shift_by;         // the amount of bits to shift right when mapping to an index of the array.
aoqi@0: 
aoqi@0: protected:
aoqi@0: 
aoqi@0:   G1BiasedMappedArrayBase() : _base(NULL), _length(0), _biased_base(NULL),
aoqi@0:     _bias(0), _shift_by(0) { }
aoqi@0: 
aoqi@0:   // Allocate a new array, generic version.
aoqi@0:   static address create_new_base_array(size_t length, size_t elem_size);
aoqi@0: 
aoqi@0:   // Initialize the members of this class. The biased start address of this array
aoqi@0:   // is the bias (in elements) multiplied by the element size.
aoqi@0:   void initialize_base(address base, size_t length, size_t bias, size_t elem_size, uint shift_by) {
aoqi@0:     assert(base != NULL, "just checking");
aoqi@0:     assert(length > 0, "just checking");
aoqi@0:     assert(shift_by < sizeof(uintptr_t) * 8, err_msg("Shifting by " SSIZE_FORMAT ", larger than word size?", (size_t) shift_by));
aoqi@0:     _base = base;
aoqi@0:     _length = length;
aoqi@0:     _biased_base = base - (bias * elem_size);
aoqi@0:     _bias = bias;
aoqi@0:     _shift_by = shift_by;
aoqi@0:   }
aoqi@0: 
aoqi@0:   // Allocate and initialize this array to cover the heap addresses in the range
aoqi@0:   // of [bottom, end).
aoqi@0:   void initialize(HeapWord* bottom, HeapWord* end, size_t target_elem_size_in_bytes, size_t mapping_granularity_in_bytes) {
aoqi@0:     assert(mapping_granularity_in_bytes > 0, "just checking");
aoqi@0:     assert(is_power_of_2(mapping_granularity_in_bytes),
aoqi@0:       err_msg("mapping granularity must be power of 2, is %zd", mapping_granularity_in_bytes));
aoqi@0:     assert((uintptr_t)bottom % mapping_granularity_in_bytes == 0,
aoqi@0:       err_msg("bottom mapping area address must be a multiple of mapping granularity %zd, is " PTR_FORMAT,
aoqi@0:         mapping_granularity_in_bytes, p2i(bottom)));
aoqi@0:     assert((uintptr_t)end % mapping_granularity_in_bytes == 0,
aoqi@0:       err_msg("end mapping area address must be a multiple of mapping granularity %zd, is " PTR_FORMAT,
aoqi@0:         mapping_granularity_in_bytes, p2i(end)));
aoqi@0:     size_t num_target_elems = (end - bottom) / (mapping_granularity_in_bytes / HeapWordSize);
aoqi@0:     idx_t bias = (uintptr_t)bottom / mapping_granularity_in_bytes;
aoqi@0:     address base = create_new_base_array(num_target_elems, target_elem_size_in_bytes);
aoqi@0:     initialize_base(base, num_target_elems, bias, target_elem_size_in_bytes, log2_intptr(mapping_granularity_in_bytes));
aoqi@0:   }
aoqi@0: 
aoqi@0:   size_t bias() const { return _bias; }
aoqi@0:   uint shift_by() const { return _shift_by; }
aoqi@0: 
aoqi@0:   void verify_index(idx_t index) const PRODUCT_RETURN;
aoqi@0:   void verify_biased_index(idx_t biased_index) const PRODUCT_RETURN;
aoqi@0:   void verify_biased_index_inclusive_end(idx_t biased_index) const PRODUCT_RETURN;
aoqi@0: 
aoqi@0: public:
aoqi@0:    // Return the length of the array in elements.
aoqi@0:    size_t length() const { return _length; }
aoqi@0: };
aoqi@0: 
aoqi@0: // Array that provides biased access and mapping from (valid) addresses in the
aoqi@0: // heap into this array.
aoqi@0: template<class T>
aoqi@0: class G1BiasedMappedArray : public G1BiasedMappedArrayBase {
aoqi@0: public:
aoqi@0:   typedef G1BiasedMappedArrayBase::idx_t idx_t;
aoqi@0: 
aoqi@0:   T* base() const { return (T*)G1BiasedMappedArrayBase::_base; }
aoqi@0:   // Return the element of the given array at the given index. Assume
aoqi@0:   // the index is valid. This is a convenience method that does sanity
aoqi@0:   // checking on the index.
aoqi@0:   T get_by_index(idx_t index) const {
aoqi@0:     verify_index(index);
aoqi@0:     return this->base()[index];
aoqi@0:   }
aoqi@0: 
aoqi@0:   // Set the element of the given array at the given index to the
aoqi@0:   // given value. Assume the index is valid. This is a convenience
aoqi@0:   // method that does sanity checking on the index.
aoqi@0:   void set_by_index(idx_t index, T value) {
aoqi@0:     verify_index(index);
aoqi@0:     this->base()[index] = value;
aoqi@0:   }
aoqi@0: 
aoqi@0:   // The raw biased base pointer.
aoqi@0:   T* biased_base() const { return (T*)G1BiasedMappedArrayBase::_biased_base; }
aoqi@0: 
aoqi@0:   // Return the element of the given array that covers the given word in the
aoqi@0:   // heap. Assumes the index is valid.
aoqi@0:   T get_by_address(HeapWord* value) const {
aoqi@0:     idx_t biased_index = ((uintptr_t)value) >> this->shift_by();
aoqi@0:     this->verify_biased_index(biased_index);
aoqi@0:     return biased_base()[biased_index];
aoqi@0:   }
aoqi@0: 
aoqi@0:   // Set the value of the array entry that corresponds to the given array.
aoqi@0:   void set_by_address(HeapWord * address, T value) {
aoqi@0:     idx_t biased_index = ((uintptr_t)address) >> this->shift_by();
aoqi@0:     this->verify_biased_index(biased_index);
aoqi@0:     biased_base()[biased_index] = value;
aoqi@0:   }
aoqi@0: 
aoqi@0: protected:
aoqi@0:   // Returns the address of the element the given address maps to
aoqi@0:   T* address_mapped_to(HeapWord* address) {
aoqi@0:     idx_t biased_index = ((uintptr_t)address) >> this->shift_by();
aoqi@0:     this->verify_biased_index_inclusive_end(biased_index);
aoqi@0:     return biased_base() + biased_index;
aoqi@0:   }
aoqi@0: 
aoqi@0: public:
aoqi@0:   // Return the smallest address (inclusive) in the heap that this array covers.
aoqi@0:   HeapWord* bottom_address_mapped() const {
aoqi@0:     return (HeapWord*) ((uintptr_t)this->bias() << this->shift_by());
aoqi@0:   }
aoqi@0: 
aoqi@0:   // Return the highest address (exclusive) in the heap that this array covers.
aoqi@0:   HeapWord* end_address_mapped() const {
aoqi@0:     return (HeapWord*) ((uintptr_t)(this->bias() + this->length()) << this->shift_by());
aoqi@0:   }
aoqi@0: 
aoqi@0: protected:
aoqi@0:   virtual T default_value() const = 0;
aoqi@0:   // Set all elements of the given array to the given value.
aoqi@0:   void clear() {
aoqi@0:     T value = default_value();
aoqi@0:     for (idx_t i = 0; i < length(); i++) {
aoqi@0:       set_by_index(i, value);
aoqi@0:     }
aoqi@0:   }
aoqi@0: public:
aoqi@0:   G1BiasedMappedArray() {}
aoqi@0: 
aoqi@0:   // Allocate and initialize this array to cover the heap addresses in the range
aoqi@0:   // of [bottom, end).
aoqi@0:   void initialize(HeapWord* bottom, HeapWord* end, size_t mapping_granularity) {
aoqi@0:     G1BiasedMappedArrayBase::initialize(bottom, end, sizeof(T), mapping_granularity);
aoqi@0:     this->clear();
aoqi@0:   }
aoqi@0: };
aoqi@0: 
aoqi@0: #endif // SHARE_VM_GC_IMPLEMENTATION_G1_G1BIASEDARRAY_HPP