/*

 * Copyright (c) 1997, 2018, 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_MEMORY_HEAP_HPP

#define SHARE_VM_MEMORY_HEAP_HPP

#include "code/codeBlob.hpp"

#include "memory/allocation.hpp"

#include "memory/virtualspace.hpp"

#include "utilities/macros.hpp"

// Blocks

class HeapBlock {

  friend class VMStructs;

 public:

  struct Header {

    size_t  _length;                             // the length in segments

    bool    _used;                               // Used bit

  };

 protected:

  union {

    Header _header;

    int64_t _padding[ (sizeof(Header) + sizeof(int64_t)-1) / sizeof(int64_t) ];

                        // pad to 0 mod 8

  };

 public:

  // Initialization

  void initialize(size_t length)                 { _header._length = length; set_used(); }

  // Accessors

  void* allocated_space() const                  { return (void*)(this + 1); }

  size_t length() const                          { return _header._length; }

  // Used/free

  void set_used()                                { _header._used = true; }

  void set_free()                                { _header._used = false; }

  bool free()                                    { return !_header._used; }

};

class FreeBlock: public HeapBlock {

  friend class VMStructs;

 protected:

  FreeBlock* _link;

 public:

  // Initialization

  void initialize(size_t length)             { HeapBlock::initialize(length); _link= NULL; }

  // Merging

  void set_length(size_t l)                  { _header._length = l; }

  // Accessors

  FreeBlock* link() const                    { return _link; }

  void set_link(FreeBlock* link)             { _link = link; }

};

class CodeHeap : public CHeapObj<mtCode> {

  friend class VMStructs;

 protected:

  VirtualSpace _memory;                          // the memory holding the blocks

  VirtualSpace _segmap;                          // the memory holding the segment map

  size_t       _number_of_committed_segments;

  size_t       _number_of_reserved_segments;

  size_t       _segment_size;

  int          _log2_segment_size;

  size_t       _next_segment;

  FreeBlock*   _freelist;

  size_t       _freelist_segments;               // No. of segments in freelist

  int          _freelist_length;

  size_t       _max_allocated_capacity;          // Peak capacity that was allocated during lifetime of the heap

  const char*  _name;                            // Name of the CodeHeap

  const int    _code_blob_type;                  // CodeBlobType it contains

  int          _blob_count;                      // Number of CodeBlobs

  int          _nmethod_count;                   // Number of nmethods

  int          _adapter_count;                   // Number of adapters

  int          _full_count;                      // Number of times the code heap was full

  enum { free_sentinel = 0xFF };

  // Helper functions

  size_t   size_to_segments(size_t size) const { return (size + _segment_size - 1) >> _log2_segment_size; }

  size_t   segments_to_size(size_t number_of_segments) const { return number_of_segments << _log2_segment_size; }

  size_t   segment_for(void* p) const            { return ((char*)p - _memory.low()) >> _log2_segment_size; }

  bool     is_segment_unused(int val) const      { return val == free_sentinel; }

  HeapBlock* block_at(size_t i) const            { return (HeapBlock*)(_memory.low() + (i << _log2_segment_size)); }

  void  mark_segmap_as_free(size_t beg, size_t end);

  void  mark_segmap_as_used(size_t beg, size_t end);

  // Freelist management helpers

  FreeBlock* following_block(FreeBlock* b);

  void insert_after(FreeBlock* a, FreeBlock* b);

  bool merge_right (FreeBlock* a);

  // Toplevel freelist management

  void add_to_freelist(HeapBlock* b);

  FreeBlock* search_freelist(size_t length);

  // Iteration helpers

  void*      next_used(HeapBlock* b) const;

  HeapBlock* block_start(void* p) const;

  // to perform additional actions on creation of executable code

  void on_code_mapping(char* base, size_t size);

  void clear();                                 // clears all heap contents

 public:

  CodeHeap(const char* name, const int code_blob_type);

  // Heap extents

  bool  reserve(ReservedSpace rs, size_t committed_size, size_t segment_size);

  bool  expand_by(size_t size);                  // expands committed memory by size

  // Memory allocation

  void* allocate (size_t size); // Allocate 'size' bytes in the code cache or return NULL

  void  deallocate(void* p);    // Deallocate memory

  // Free the tail of segments allocated by the last call to 'allocate()' which exceed 'used_size'.

  // ATTENTION: this is only safe to use if there was no other call to 'allocate()' after

  //            'p' was allocated. Only intended for freeing memory which would be otherwise

  //            wasted after the interpreter generation because we don't know the interpreter size

  //            beforehand and we also can't easily relocate the interpreter to a new location.

  void  deallocate_tail(void* p, size_t used_size);

  // Attributes

  char* low_boundary() const                     { return _memory.low_boundary(); }

  char* high() const                             { return _memory.high(); }

  char* high_boundary() const                    { return _memory.high_boundary(); }

  bool contains(const void* p) const             { return low_boundary() <= p && p < high(); }

  bool contains_blob(const CodeBlob* blob) const {

    // AOT CodeBlobs (i.e. AOTCompiledMethod) objects aren't allocated in the AOTCodeHeap but on the C-Heap.

    // Only the code they are pointing to is located in the AOTCodeHeap. All other CodeBlobs are allocated

    // directly in their corresponding CodeHeap with their code appended to the actual C++ object.

    // So all CodeBlobs except AOTCompiledMethod are continuous in memory with their data and code while

    // AOTCompiledMethod and their code/data is distributed in the C-Heap. This means we can use the

    // address of a CodeBlob object in order to locate it in its heap while we have to use the address

    // of the actual code an AOTCompiledMethod object is pointing to in order to locate it.

    // Notice that for an ordinary CodeBlob with code size zero, code_begin() may point beyond the object!

    const void* start = AOT_ONLY( (code_blob_type() == CodeBlobType::AOT) ? blob->code_begin() : ) (void*)blob;

    return contains(start);

  }

  virtual void* find_start(void* p)     const;   // returns the block containing p or NULL

  virtual CodeBlob* find_blob_unsafe(void* start) const;

  size_t alignment_unit()       const;           // alignment of any block

  size_t alignment_offset()     const;           // offset of first byte of any block, within the enclosing alignment unit

  static size_t header_size();                   // returns the header size for each heap block

  size_t segment_size()         const { return _segment_size; }  // for CodeHeapState

  HeapBlock* first_block() const;                                // for CodeHeapState

  HeapBlock* next_block(HeapBlock* b) const;                     // for CodeHeapState

  FreeBlock* freelist()         const { return _freelist; }      // for CodeHeapState

  size_t allocated_in_freelist() const           { return _freelist_segments * CodeCacheSegmentSize; }

  int    freelist_length()       const           { return _freelist_length; } // number of elements in the freelist

  // returns the first block or NULL

  virtual void* first() const                    { return next_used(first_block()); }

  // returns the next block given a block p or NULL

  virtual void* next(void* p) const              { return next_used(next_block(block_start(p))); }

  // Statistics

  size_t capacity() const;

  size_t max_capacity() const;

  int    allocated_segments() const;

  size_t allocated_capacity() const;

  size_t max_allocated_capacity() const          { return _max_allocated_capacity; }

  size_t unallocated_capacity() const            { return max_capacity() - allocated_capacity(); }

  // Returns true if the CodeHeap contains CodeBlobs of the given type

  bool accepts(int code_blob_type) const         { return (_code_blob_type == CodeBlobType::All) ||

                                                          (_code_blob_type == code_blob_type); }

  int code_blob_type() const                     { return _code_blob_type; }

  // Debugging / Profiling

  const char* name() const                       { return _name; }

  int         blob_count()                       { return _blob_count; }

  int         nmethod_count()                    { return _nmethod_count; }

  void    set_nmethod_count(int count)           {        _nmethod_count = count; }

  int         adapter_count()                    { return _adapter_count; }

  void    set_adapter_count(int count)           {        _adapter_count = count; }

  int         full_count()                       { return _full_count; }

  void        report_full()                      {        _full_count++; }

private:

  size_t heap_unallocated_capacity() const;

public:

  // Debugging

  void verify() PRODUCT_RETURN;

  void print()  PRODUCT_RETURN;

};

#endif // SHARE_VM_MEMORY_HEAP_HPP