/*

 * Copyright (c) 1997, 2019, 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

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 */

#ifndef SHARE_MEMORY_VIRTUALSPACE_HPP

#define SHARE_MEMORY_VIRTUALSPACE_HPP

#include "utilities/globalDefinitions.hpp"

class outputStream;

// ReservedSpace is a data structure for reserving a contiguous address range.

class ReservedSpace {

  friend class VMStructs;

 protected:

  char*  _base;

  size_t _size;

  size_t _noaccess_prefix;

  size_t _alignment;

  bool   _special;

  int    _fd_for_heap;

 private:

  bool   _executable;

  // ReservedSpace

  ReservedSpace(char* base, size_t size, size_t alignment, bool special,

                bool executable);

 protected:

  void initialize(size_t size, size_t alignment, bool large,

                  char* requested_address,

                  bool executable);

 public:

  // Constructor

  ReservedSpace();

  // Initialize the reserved space with the given size. If preferred_page_size

  // is set, use this as minimum page size/alignment. This may waste some space

  // if the given size is not aligned to that value, as the reservation will be

  // aligned up to the final alignment in this case.

  ReservedSpace(size_t size, size_t preferred_page_size = 0);

  ReservedSpace(size_t size, size_t alignment, bool large,

                char* requested_address = NULL);

  ReservedSpace(size_t size, size_t alignment, bool large, bool executable);

  // Accessors

  char*  base()            const { return _base;      }

  size_t size()            const { return _size;      }

  char*  end()             const { return _base + _size; }

  size_t alignment()       const { return _alignment; }

  bool   special()         const { return _special;   }

  bool   executable()      const { return _executable;   }

  size_t noaccess_prefix() const { return _noaccess_prefix;   }

  bool is_reserved()       const { return _base != NULL; }

  void release();

  // Splitting

  ReservedSpace first_part(size_t partition_size, size_t alignment,

                           bool split = false, bool realloc = true);

  ReservedSpace last_part (size_t partition_size, size_t alignment);

  // These simply call the above using the default alignment.

  inline ReservedSpace first_part(size_t partition_size,

                                  bool split = false, bool realloc = true);

  inline ReservedSpace last_part (size_t partition_size);

  // Alignment

  static size_t page_align_size_up(size_t size);

  static size_t page_align_size_down(size_t size);

  static size_t allocation_align_size_up(size_t size);

  bool contains(const void* p) const {

    return (base() <= ((char*)p)) && (((char*)p) < (base() + size()));

  }

};

ReservedSpace

ReservedSpace::first_part(size_t partition_size, bool split, bool realloc)

{

  return first_part(partition_size, alignment(), split, realloc);

}

ReservedSpace ReservedSpace::last_part(size_t partition_size)

{

  return last_part(partition_size, alignment());

}

// Class encapsulating behavior specific of memory space reserved for Java heap.

class ReservedHeapSpace : public ReservedSpace {

 private:

  void try_reserve_heap(size_t size, size_t alignment, bool large,

                        char *requested_address);

  void try_reserve_range(char *highest_start, char *lowest_start,

                         size_t attach_point_alignment, char *aligned_HBMA,

                         char *upper_bound, size_t size, size_t alignment, bool large);

  void initialize_compressed_heap(const size_t size, size_t alignment, bool large);

  // Create protection page at the beginning of the space.

  void establish_noaccess_prefix();

 public:

  // Constructor. Tries to find a heap that is good for compressed oops.

  // heap_allocation_directory is the path to the backing memory for Java heap. When set, Java heap will be allocated

  // on the device which is managed by the file system where the directory resides.

  ReservedHeapSpace(size_t size, size_t forced_base_alignment, bool large, const char* heap_allocation_directory = NULL);

  // Returns the base to be used for compression, i.e. so that null can be

  // encoded safely and implicit null checks can work.

  char *compressed_oop_base() { return _base - _noaccess_prefix; }

};

// Class encapsulating behavior specific memory space for Code

class ReservedCodeSpace : public ReservedSpace {

 public:

  // Constructor

  ReservedCodeSpace(size_t r_size, size_t rs_align, bool large);

};

// VirtualSpace is data structure for committing a previously reserved address range in smaller chunks.

class VirtualSpace {

  friend class VMStructs;

 private:

  // Reserved area

  char* _low_boundary;

  char* _high_boundary;

  // Committed area

  char* _low;

  char* _high;

  // The entire space has been committed and pinned in memory, no

  // os::commit_memory() or os::uncommit_memory().

  bool _special;

  // Need to know if commit should be executable.

  bool   _executable;

  // MPSS Support

  // Each virtualspace region has a lower, middle, and upper region.

  // Each region has an end boundary and a high pointer which is the

  // high water mark for the last allocated byte.

  // The lower and upper unaligned to LargePageSizeInBytes uses default page.

  // size.  The middle region uses large page size.

  char* _lower_high;

  char* _middle_high;

  char* _upper_high;

  char* _lower_high_boundary;

  char* _middle_high_boundary;

  char* _upper_high_boundary;

  size_t _lower_alignment;

  size_t _middle_alignment;

  size_t _upper_alignment;

  // MPSS Accessors

  char* lower_high() const { return _lower_high; }

  char* middle_high() const { return _middle_high; }

  char* upper_high() const { return _upper_high; }

  char* lower_high_boundary() const { return _lower_high_boundary; }

  char* middle_high_boundary() const { return _middle_high_boundary; }

  char* upper_high_boundary() const { return _upper_high_boundary; }

  size_t lower_alignment() const { return _lower_alignment; }

  size_t middle_alignment() const { return _middle_alignment; }

  size_t upper_alignment() const { return _upper_alignment; }

 public:

  // Committed area

  char* low()  const { return _low; }

  char* high() const { return _high; }

  // Reserved area

  char* low_boundary()  const { return _low_boundary; }

  char* high_boundary() const { return _high_boundary; }

#if INCLUDE_AOT

  // Set boundaries for code section in AOT library.

  void set_low_boundary(char *p)  { _low_boundary = p; }

  void set_high_boundary(char *p) { _high_boundary = p; }

  void set_low(char *p)           { _low = p; }

  void set_high(char *p)          { _high = p; }

#endif

  bool special() const { return _special; }

 public:

  // Initialization

  VirtualSpace();

  bool initialize_with_granularity(ReservedSpace rs, size_t committed_byte_size, size_t max_commit_ganularity);

  bool initialize(ReservedSpace rs, size_t committed_byte_size);

  // Destruction

  ~VirtualSpace();

  // Reserved memory

  size_t reserved_size() const;

  // Actually committed OS memory

  size_t actual_committed_size() const;

  // Memory used/expanded in this virtual space

  size_t committed_size() const;

  // Memory left to use/expand in this virtual space

  size_t uncommitted_size() const;

  bool   contains(const void* p) const;

  // Operations

  // returns true on success, false otherwise

  bool expand_by(size_t bytes, bool pre_touch = false);

  void shrink_by(size_t bytes);

  void release();

  void check_for_contiguity() PRODUCT_RETURN;

  // Debugging

  void print_on(outputStream* out) PRODUCT_RETURN;

  void print();

};

#endif // SHARE_MEMORY_VIRTUALSPACE_HPP