/*

 * 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

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 *

 */

#include "precompiled.hpp"

#include "memory/heap.hpp"

#include "oops/oop.inline.hpp"

#include "runtime/os.hpp"

#include "services/memTracker.hpp"

#include "utilities/align.hpp"

size_t CodeHeap::header_size() {

  return sizeof(HeapBlock);

}

// Implementation of Heap

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

  : _code_blob_type(code_blob_type) {

  _name                         = name;

  _number_of_committed_segments = 0;

  _number_of_reserved_segments  = 0;

  _segment_size                 = 0;

  _log2_segment_size            = 0;

  _next_segment                 = 0;

  _freelist                     = NULL;

  _freelist_segments            = 0;

  _freelist_length              = 0;

  _max_allocated_capacity       = 0;

  _blob_count                   = 0;

  _nmethod_count                = 0;

  _adapter_count                = 0;

  _full_count                   = 0;

}

// The segmap is marked free for that part of the heap

// which has not been allocated yet (beyond _next_segment).

// "Allocated" space in this context means there exists a

// HeapBlock or a FreeBlock describing this space.

// This method takes segment map indices as range boundaries

void CodeHeap::mark_segmap_as_free(size_t beg, size_t end) {

  assert(             beg <  _number_of_committed_segments, "interval begin out of bounds");

  assert(beg < end && end <= _number_of_committed_segments, "interval end   out of bounds");

  // Don't do unpredictable things in PRODUCT build

  if (beg < end) {

    // setup _segmap pointers for faster indexing

    address p = (address)_segmap.low() + beg;

    address q = (address)_segmap.low() + end;

    // initialize interval

    memset(p, free_sentinel, q-p);

  }

}

// Don't get confused here.

// All existing blocks, no matter if they are used() or free(),

// have their segmap marked as used. This allows to find the

// block header (HeapBlock or FreeBlock) for any pointer

// within the allocated range (upper limit: _next_segment).

  assert(             beg <  _number_of_committed_segments, "interval begin out of bounds");

  assert(beg < end && end <= _number_of_committed_segments, "interval end   out of bounds");

  // Don't do unpredictable things in PRODUCT build

  if (beg < end) {

    // setup _segmap pointers for faster indexing

    address p = (address)_segmap.low() + beg;

    address q = (address)_segmap.low() + end;

    // initialize interval

    }

  }

}

void CodeHeap::invalidate(size_t beg, size_t end, size_t hdr_size) {

#ifndef PRODUCT

  // Fill the given range with some bad value.

  // length is expected to be in segment_size units.

  // This prevents inadvertent execution of code leftover from previous use.

  char* p = low_boundary() + segments_to_size(beg) + hdr_size;

  memset(p, badCodeHeapNewVal, segments_to_size(end-beg)-hdr_size);

#endif

}

void CodeHeap::clear(size_t beg, size_t end) {

  mark_segmap_as_free(beg, end);

  invalidate(beg, end, 0);

}

void CodeHeap::clear() {

  _next_segment = 0;

  clear(_next_segment, _number_of_committed_segments);

}

static size_t align_to_page_size(size_t size) {

  const size_t alignment = (size_t)os::vm_page_size();

  assert(is_power_of_2(alignment), "no kidding ???");

  return (size + alignment - 1) & ~(alignment - 1);

}

void CodeHeap::on_code_mapping(char* base, size_t size) {

#ifdef LINUX

  extern void linux_wrap_code(char* base, size_t size);

  linux_wrap_code(base, size);

#endif

}

bool CodeHeap::reserve(ReservedSpace rs, size_t committed_size, size_t segment_size) {

  assert(rs.size() >= committed_size, "reserved < committed");

  assert(segment_size >= sizeof(FreeBlock), "segment size is too small");

  assert(is_power_of_2(segment_size), "segment_size must be a power of 2");

  _segment_size      = segment_size;

  _log2_segment_size = exact_log2(segment_size);

  // Reserve and initialize space for _memory.

  size_t page_size = os::vm_page_size();

  if (os::can_execute_large_page_memory()) {

    const size_t min_pages = 8;

    page_size = MIN2(os::page_size_for_region_aligned(committed_size, min_pages),

                     os::page_size_for_region_aligned(rs.size(), min_pages));

  }

  const size_t granularity = os::vm_allocation_granularity();

  const size_t c_size = align_up(committed_size, page_size);

  os::trace_page_sizes(_name, committed_size, rs.size(), page_size,

                       rs.base(), rs.size());

  if (!_memory.initialize(rs, c_size)) {

    return false;

  }

  on_code_mapping(_memory.low(), _memory.committed_size());

  _number_of_committed_segments = size_to_segments(_memory.committed_size());

  _number_of_reserved_segments  = size_to_segments(_memory.reserved_size());

  assert(_number_of_reserved_segments >= _number_of_committed_segments, "just checking");

  const size_t reserved_segments_alignment = MAX2((size_t)os::vm_page_size(), granularity);

  const size_t reserved_segments_size = align_up(_number_of_reserved_segments, reserved_segments_alignment);

  const size_t committed_segments_size = align_to_page_size(_number_of_committed_segments);

  // reserve space for _segmap

  if (!_segmap.initialize(reserved_segments_size, committed_segments_size)) {

    return false;

  }

  MemTracker::record_virtual_memory_type((address)_segmap.low_boundary(), mtCode);

  assert(_segmap.committed_size() >= (size_t) _number_of_committed_segments, "could not commit  enough space for segment map");

  assert(_segmap.reserved_size()  >= (size_t) _number_of_reserved_segments , "could not reserve enough space for segment map");

  assert(_segmap.reserved_size()  >= _segmap.committed_size()     , "just checking");

  // initialize remaining instance variables, heap memory and segmap

  clear();

  return true;

}

bool CodeHeap::expand_by(size_t size) {

  // expand _memory space

  size_t dm = align_to_page_size(_memory.committed_size() + size) - _memory.committed_size();

  if (dm > 0) {

    // Use at least the available uncommitted space if 'size' is larger

    if (_memory.uncommitted_size() != 0 && dm > _memory.uncommitted_size()) {

      dm = _memory.uncommitted_size();

    }

    char* base = _memory.low() + _memory.committed_size();

    if (!_memory.expand_by(dm)) return false;

    on_code_mapping(base, dm);

    size_t i = _number_of_committed_segments;

    _number_of_committed_segments = size_to_segments(_memory.committed_size());

    assert(_number_of_reserved_segments == size_to_segments(_memory.reserved_size()), "number of reserved segments should not change");

    assert(_number_of_reserved_segments >= _number_of_committed_segments, "just checking");

    // expand _segmap space

    size_t ds = align_to_page_size(_number_of_committed_segments) - _segmap.committed_size();

    if ((ds > 0) && !_segmap.expand_by(ds)) {

      return false;

    }

    assert(_segmap.committed_size() >= (size_t) _number_of_committed_segments, "just checking");

    // initialize additional space (heap memory and segmap)

    clear(i, _number_of_committed_segments);

  }

  return true;

}

void* CodeHeap::allocate(size_t instance_size) {

  size_t number_of_segments = size_to_segments(instance_size + header_size());

  assert(segments_to_size(number_of_segments) >= sizeof(FreeBlock), "not enough room for FreeList");

  // First check if we can satisfy request from freelist

  NOT_PRODUCT(verify());

  HeapBlock* block = search_freelist(number_of_segments);

  NOT_PRODUCT(verify());

  if (block != NULL) {

    guarantee((char*) block >= _memory.low_boundary() && (char*) block < _memory.high(),

              "The newly allocated block " INTPTR_FORMAT " is not within the heap "

              "starting with "  INTPTR_FORMAT " and ending with "  INTPTR_FORMAT,

              p2i(block), p2i(_memory.low_boundary()), p2i(_memory.high()));

    _max_allocated_capacity = MAX2(_max_allocated_capacity, allocated_capacity());

    _blob_count++;

    return block->allocated_space();

  }

  // Ensure minimum size for allocation to the heap.

  number_of_segments = MAX2((int)CodeCacheMinBlockLength, (int)number_of_segments);

  if (_next_segment + number_of_segments <= _number_of_committed_segments) {

    _next_segment += number_of_segments;

              "The newly allocated block " INTPTR_FORMAT " is not within the heap "

              "starting with "  INTPTR_FORMAT " and ending with " INTPTR_FORMAT,

    _max_allocated_capacity = MAX2(_max_allocated_capacity, allocated_capacity());

    _blob_count++;

  } else {

    return NULL;

  }

}

// Split the given block into two at the given segment.

// This is helpful when a block was allocated too large

// to trim off the unused space at the end (interpreter).

// It also helps with splitting a large free block during allocation.

// Usage state (used or free) must be set by caller since

// we don't know if the resulting blocks will be used or free.

// split_at is the segment number (relative to segment_for(b))

//          where the split happens. The segment with relative

//          number split_at is the first segment of the split-off block.

HeapBlock* CodeHeap::split_block(HeapBlock *b, size_t split_at) {

  if (b == NULL) return NULL;

  // After the split, both blocks must have a size of at least CodeCacheMinBlockLength

  assert((split_at >= CodeCacheMinBlockLength) && (split_at + CodeCacheMinBlockLength <= b->length()),

         "split position(%d) out of range [0..%d]", (int)split_at, (int)b->length());

  size_t split_segment = segment_for(b) + split_at;

  size_t b_size        = b->length();

  size_t newb_size     = b_size - split_at;

  HeapBlock* newb = block_at(split_segment);

  newb->set_length(newb_size);

  b->set_length(split_at);

  return newb;

}

void CodeHeap::deallocate_tail(void* p, size_t used_size) {

  assert(p == find_start(p), "illegal deallocation");

  // Find start of HeapBlock

  HeapBlock* b = (((HeapBlock *)p) - 1);

  assert(b->allocated_space() == p, "sanity check");

  size_t actual_number_of_segments = b->length();

  size_t used_number_of_segments   = size_to_segments(used_size + header_size());

  size_t unused_number_of_segments = actual_number_of_segments - used_number_of_segments;

  guarantee(used_number_of_segments <= actual_number_of_segments, "Must be!");

  HeapBlock* f = split_block(b, used_number_of_segments);

  add_to_freelist(f);

  NOT_PRODUCT(verify());

}

void CodeHeap::deallocate(void* p) {

  assert(p == find_start(p), "illegal deallocation");

  // Find start of HeapBlock

  HeapBlock* b = (((HeapBlock *)p) - 1);

  assert(b->allocated_space() == p, "sanity check");

  guarantee((char*) b >= _memory.low_boundary() && (char*) b < _memory.high(),

            "The block to be deallocated " INTPTR_FORMAT " is not within the heap "

            "starting with "  INTPTR_FORMAT " and ending with " INTPTR_FORMAT,

            p2i(b), p2i(_memory.low_boundary()), p2i(_memory.high()));

  add_to_freelist(b);

  NOT_PRODUCT(verify());

}

/**

 *

 *          code cache          segmap

 *         -----------        ---------

 * seg 1   | nm 1    |   ->   | 0     |

 * seg 2   | nm 1    |   ->   | 1     |

 * ...     | nm 1    |   ->   | ..    |

 * seg m   | nm 2    |   ->   | 0     |

 * seg m+1 | nm 2    |   ->   | 1     |

 * ...     | nm 2    |   ->   | 2     |

 * ...     | nm 2    |   ->   | ..    |

 * ...     | nm 2    |   ->   |       |

 *

 */

  if (!contains(p)) {

    return NULL;

  }

  address seg_map = (address)_segmap.low();

  if (is_segment_unused(seg_map[seg_idx])) {

    return NULL;

  }

  while (seg_map[seg_idx] > 0) {

    seg_idx -= (int)seg_map[seg_idx];

  }

}

CodeBlob* CodeHeap::find_blob_unsafe(void* start) const {

  CodeBlob* result = (CodeBlob*)CodeHeap::find_start(start);

}

size_t CodeHeap::alignment_unit() const {

  // this will be a power of two

  return _segment_size;

}

size_t CodeHeap::alignment_offset() const {