#include "code/codeCache.hpp"

#include "gc_implementation/g1/heapRegion.hpp"

#include "memory/heap.hpp"

#include "oops/oop.inline.hpp"

#include "utilities/hashtable.inline.hpp"

#include "utilities/stack.inline.hpp"

class CodeRootSetTable : public Hashtable<nmethod*, mtGC> {

  friend class G1CodeRootSetTest;

  typedef HashtableEntry<nmethod*, mtGC> Entry;

  static CodeRootSetTable* volatile _purge_list;

  CodeRootSetTable* _purge_next;

  unsigned int compute_hash(nmethod* nm) {

    uintptr_t hash = (uintptr_t)nm;

    return hash ^ (hash >> 7); // code heap blocks are 128byte aligned

  }

  Entry* new_entry(nmethod* nm);

 public:

  CodeRootSetTable(int size) : Hashtable<nmethod*, mtGC>(size, sizeof(Entry)), _purge_next(NULL) {}

  ~CodeRootSetTable();

  // Needs to be protected locks

  bool add(nmethod* nm);

  bool remove(nmethod* nm);

  // Can be called without locking

  bool contains(nmethod* nm);

  int entry_size() const { return BasicHashtable<mtGC>::entry_size(); }

  void copy_to(CodeRootSetTable* new_table);

  void nmethods_do(CodeBlobClosure* blk);

  template<typename CB>

  void remove_if(CB& should_remove);

  static void purge_list_append(CodeRootSetTable* tbl);

  static void purge();

  static size_t static_mem_size() {

    return sizeof(_purge_list);

  }

};

CodeRootSetTable* volatile CodeRootSetTable::_purge_list = NULL;

CodeRootSetTable::Entry* CodeRootSetTable::new_entry(nmethod* nm) {

  unsigned int hash = compute_hash(nm);

  Entry* entry = (Entry*) new_entry_free_list();

  if (entry == NULL) {

    entry = (Entry*) NEW_C_HEAP_ARRAY2(char, entry_size(), mtGC, CURRENT_PC);

  }

  entry->set_next(NULL);

  entry->set_hash(hash);

  entry->set_literal(nm);

  return entry;

CodeRootSetTable::~CodeRootSetTable() {

  for (int index = 0; index < table_size(); ++index) {

    for (Entry* e = bucket(index); e != NULL; ) {

      Entry* to_remove = e;

      // read next before freeing.

      e = e->next();

      unlink_entry(to_remove);

      FREE_C_HEAP_ARRAY(char, to_remove, mtGC);

  }

  assert(number_of_entries() == 0, "should have removed all entries");

  free_buckets();

  for (BasicHashtableEntry<mtGC>* e = new_entry_free_list(); e != NULL; e = new_entry_free_list()) {

    FREE_C_HEAP_ARRAY(char, e, mtGC);

bool CodeRootSetTable::add(nmethod* nm) {

  if (!contains(nm)) {

    Entry* e = new_entry(nm);

    int index = hash_to_index(e->hash());

    add_entry(index, e);

    return true;

  }

  return false;

}

bool CodeRootSetTable::contains(nmethod* nm) {

  int index = hash_to_index(compute_hash(nm));

  for (Entry* e = bucket(index); e != NULL; e = e->next()) {

    if (e->literal() == nm) {

      return true;

    }

  }

  return false;

}

bool CodeRootSetTable::remove(nmethod* nm) {

  int index = hash_to_index(compute_hash(nm));

  Entry* previous = NULL;

  for (Entry* e = bucket(index); e != NULL; previous = e, e = e->next()) {

    if (e->literal() == nm) {

      if (previous != NULL) {

        previous->set_next(e->next());

      } else {

        set_entry(index, e->next());

      }

      free_entry(e);

void CodeRootSetTable::copy_to(CodeRootSetTable* new_table) {

  for (int index = 0; index < table_size(); ++index) {

    for (Entry* e = bucket(index); e != NULL; e = e->next()) {

      new_table->add(e->literal());

    }

  }

  new_table->copy_freelist(this);

void CodeRootSetTable::nmethods_do(CodeBlobClosure* blk) {

  for (int index = 0; index < table_size(); ++index) {

    for (Entry* e = bucket(index); e != NULL; e = e->next()) {

      blk->do_code_blob(e->literal());

    }

  }

template<typename CB>

void CodeRootSetTable::remove_if(CB& should_remove) {

  for (int index = 0; index < table_size(); ++index) {

    Entry* previous = NULL;

    Entry* e = bucket(index);

    while (e != NULL) {

      Entry* next = e->next();

      if (should_remove(e->literal())) {

        if (previous != NULL) {

          previous->set_next(next);

        } else {

          set_entry(index, next);

        }

        free_entry(e);

      } else {

        previous = e;

      }

      e = next;

    }

  }

}

G1CodeRootSet::~G1CodeRootSet() {

  delete _table;

CodeRootSetTable* G1CodeRootSet::load_acquire_table() {

  return (CodeRootSetTable*) OrderAccess::load_ptr_acquire(&_table);

}

void G1CodeRootSet::allocate_small_table() {

  _table = new CodeRootSetTable(SmallSize);

}

void CodeRootSetTable::purge_list_append(CodeRootSetTable* table) {

  for (;;) {

    table->_purge_next = _purge_list;

    CodeRootSetTable* old = (CodeRootSetTable*) Atomic::cmpxchg_ptr(table, &_purge_list, table->_purge_next);

    if (old == table->_purge_next) {

      break;

    }

  }

}

void CodeRootSetTable::purge() {

  CodeRootSetTable* table = _purge_list;

  _purge_list = NULL;

  while (table != NULL) {

    CodeRootSetTable* to_purge = table;

    table = table->_purge_next;

    delete to_purge;

void G1CodeRootSet::move_to_large() {

  CodeRootSetTable* temp = new CodeRootSetTable(LargeSize);

  _table->copy_to(temp);

  CodeRootSetTable::purge_list_append(_table);

  OrderAccess::release_store_ptr(&_table, temp);

void G1CodeRootSet::purge() {

  CodeRootSetTable::purge();

}

size_t G1CodeRootSet::static_mem_size() {

  return CodeRootSetTable::static_mem_size();

}

void G1CodeRootSet::add(nmethod* method) {

  bool added = false;

  if (is_empty()) {

    allocate_small_table();

  }

  added = _table->add(method);

  if (_length == Threshold) {

    move_to_large();

  }

  if (added) {

    ++_length;

  }

}

bool G1CodeRootSet::remove(nmethod* method) {

  bool removed = false;

  if (_table != NULL) {

    removed = _table->remove(method);

  }

  if (removed) {

    _length--;

    if (_length == 0) {

      clear();

    }

  }

  return removed;

}

bool G1CodeRootSet::contains(nmethod* method) {

  CodeRootSetTable* table = load_acquire_table();

  if (table != NULL) {

    return table->contains(method);

  return false;

}

void G1CodeRootSet::clear() {

  delete _table;

  _table = NULL;

  _length = 0;

}

size_t G1CodeRootSet::mem_size() {

  return sizeof(*this) +

      (_table != NULL ? sizeof(CodeRootSetTable) + _table->entry_size() * _length : 0);

}

void G1CodeRootSet::nmethods_do(CodeBlobClosure* blk) const {

  if (_table != NULL) {

    _table->nmethods_do(blk);

  }

}

class CleanCallback : public StackObj {

  class PointsIntoHRDetectionClosure : public OopClosure {

    HeapRegion* _hr;

   public:

    bool _points_into;

    PointsIntoHRDetectionClosure(HeapRegion* hr) : _hr(hr), _points_into(false) {}

    void do_oop(narrowOop* o) {

      do_oop_work(o);

    }

    void do_oop(oop* o) {

      do_oop_work(o);

    }

    template <typename T>

    void do_oop_work(T* p) {

      if (_hr->is_in(oopDesc::load_decode_heap_oop(p))) {

        _points_into = true;

      }

    }

  };

  PointsIntoHRDetectionClosure _detector;

  CodeBlobToOopClosure _blobs;

 public:

  CleanCallback(HeapRegion* hr) : _detector(hr), _blobs(&_detector, !CodeBlobToOopClosure::FixRelocations) {}

  bool operator() (nmethod* nm) {

    _detector._points_into = false;

    _blobs.do_code_blob(nm);

    return _detector._points_into;

  }

};

void G1CodeRootSet::clean(HeapRegion* owner) {

  CleanCallback should_clean(owner);

  if (_table != NULL) {

    _table->remove_if(should_clean);

  }

class G1CodeRootSetTest {

 public:

  static void test() {

    {

      G1CodeRootSet set1;

      assert(set1.is_empty(), "Code root set must be initially empty but is not.");

      assert(G1CodeRootSet::static_mem_size() == sizeof(void*),

          err_msg("The code root set's static memory usage is incorrect, "SIZE_FORMAT" bytes", G1CodeRootSet::static_mem_size()));

      set1.add((nmethod*)1);

      assert(set1.length() == 1, err_msg("Added exactly one element, but set contains "

          SIZE_FORMAT" elements", set1.length()));

      const size_t num_to_add = (size_t)G1CodeRootSet::Threshold + 1;

      for (size_t i = 1; i <= num_to_add; i++) {

        set1.add((nmethod*)1);

      }

      assert(set1.length() == 1,

          err_msg("Duplicate detection should not have increased the set size but "

              "is "SIZE_FORMAT, set1.length()));

      for (size_t i = 2; i <= num_to_add; i++) {

        set1.add((nmethod*)(uintptr_t)(i));

      }

      assert(set1.length() == num_to_add,

          err_msg("After adding in total "SIZE_FORMAT" distinct code roots, they "

              "need to be in the set, but there are only "SIZE_FORMAT,

              num_to_add, set1.length()));

      assert(CodeRootSetTable::_purge_list != NULL, "should have grown to large hashtable");

      size_t num_popped = 0;

      for (size_t i = 1; i <= num_to_add; i++) {

        bool removed = set1.remove((nmethod*)i);

        if (removed) {

          num_popped += 1;

        } else {

          break;

        }

      }

      assert(num_popped == num_to_add,

          err_msg("Managed to pop "SIZE_FORMAT" code roots, but only "SIZE_FORMAT" "

              "were added", num_popped, num_to_add));

      assert(CodeRootSetTable::_purge_list != NULL, "should have grown to large hashtable");

      G1CodeRootSet::purge();

      assert(CodeRootSetTable::_purge_list == NULL, "should have purged old small tables");

    }

  }

};

void TestCodeCacheRemSet_test() {

  G1CodeRootSetTest::test();