Make GlobalHandle::NodeBlock deletable

R=mstarzinger@chromium.org
BUG=

Review URL: https://codereview.chromium.org/21042004

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@16040 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/global-handles.h

@@ -156,6 +156,9 @@ class GlobalHandles {
     return number_of_global_handles_;
   }
 
+  // Returns the current number of allocated blocks
+  int block_count() const { return number_of_blocks_; }
+
   // Clear the weakness of a global handle.
   static void ClearWeakness(Object** location);
 
@@ -275,11 +278,14 @@ class GlobalHandles {
 #ifdef DEBUG
   void PrintStats();
   void Print();
+  void VerifyBlockInvariants();
 #endif
 
  private:
   explicit GlobalHandles(Isolate* isolate);
 
+  void SortBlocks(bool shouldPrune);
+
   // Migrates data from the internal representation (object_group_connections_,
   // retainer_infos_ and implicit_ref_connections_) to the public and more
   // efficient representation (object_groups_ and implicit_ref_groups_).
@@ -293,20 +299,64 @@ class GlobalHandles {
   class Node;
   class NodeBlock;
   class NodeIterator;
+  class BlockListIterator;
+  // Base class for NodeBlock
+  class BlockList {
+   public:
+    BlockList();
+    ~BlockList() { ASSERT(IsDetached()); }
+    void Detach();
+    void InsertAsHead(BlockList* block) {
+      ASSERT(IsAnchor());
+      InsertAsNext(block);
+    }
+    void InsertAsTail(BlockList* block) {
+      ASSERT(IsAnchor());
+      prev_block_->InsertAsNext(block);
+    }
+    inline bool IsAnchor() { return first_free_ == NULL && used_nodes_ == 0; }
+    inline bool IsDetached() {
+      ASSERT_EQ(prev_block_ == this, next_block_ == this);
+      return prev_block_ == this;
+    }
+    bool HasAtLeastLength(int length);
+    bool IsUnused() { return used_nodes_ == 0; }
+    int used_nodes() const { return used_nodes_; }
+    BlockList* next() { return next_block_; }
+    BlockList* prev() { return prev_block_; }
+#ifdef DEBUG
+    int LengthOfFreeList();
+#endif
+    static void SortBlocks(GlobalHandles* global_handles, bool prune);
+
+   protected:
+    BlockList* prev_block_;
+    BlockList* next_block_;
+    Node* first_free_;
+    int used_nodes_;
+
+   private:
+    // Needed for quicksort
+    static int CompareBlocks(const void* a, const void* b);
+    void InsertAsNext(BlockList* block);
+    DISALLOW_COPY_AND_ASSIGN(BlockList);
+  };
 
   Isolate* isolate_;
 
+  // Field always containing the number of blocks allocated.
+  int number_of_blocks_;
   // Field always containing the number of handles to global objects.
   int number_of_global_handles_;
 
-  // List of all allocated node blocks.
-  NodeBlock* first_block_;
-
-  // List of node blocks with used nodes.
-  NodeBlock* first_used_block_;
+  // Anchors for doubly linked lists of blocks
+  BlockList full_blocks_;
+  BlockList non_full_blocks_;
 
-  // Free list of nodes.
-  Node* first_free_;
+  // An array of all the anchors held by GlobalHandles.
+  // This simplifies iteration across all blocks.
+  static const int kAllAnchorsSize = 2;
+  BlockList*  all_anchors_[kAllAnchorsSize];
 
   // Contains all nodes holding new space objects. Note: when the list
   // is accessed, some of the objects may have been promoted already.

test/cctest/cctest.h

@@ -300,4 +300,57 @@ static inline void SimulateFullSpace(v8::internal::PagedSpace* space) {
 }
 
 
+// Adapted from http://en.wikipedia.org/wiki/Multiply-with-carry
+class RandomNumberGenerator {
+ public:
+  RandomNumberGenerator() {
+    init();
+  }
+
+  void init(uint32_t seed = 0x5688c73e) {
+    static const uint32_t phi = 0x9e3779b9;
+    c = 362436;
+    i = kQSize-1;
+    Q[0] = seed;
+    Q[1] = seed + phi;
+    Q[2] = seed + phi + phi;
+    for (unsigned j = 3; j < kQSize; j++) {
+      Q[j] = Q[j - 3] ^ Q[j - 2] ^ phi ^ j;
+    }
+  }
+
+  uint32_t next() {
+    uint64_t a = 18782;
+    uint32_t r = 0xfffffffe;
+    i = (i + 1) & (kQSize-1);
+    uint64_t t = a * Q[i] + c;
+    c = (t >> 32);
+    uint32_t x = static_cast<uint32_t>(t + c);
+    if (x < c) {
+      x++;
+      c++;
+    }
+    return (Q[i] = r - x);
+  }
+
+  uint32_t next(int max) {
+    return next() % max;
+  }
+
+  bool next(double threshold) {
+    ASSERT(threshold >= 0.0 && threshold <= 1.0);
+    if (threshold == 1.0) return true;
+    if (threshold == 0.0) return false;
+    uint32_t value = next() % 100000;
+    return threshold > static_cast<double>(value)/100000.0;
+  }
+
+ private:
+  static const uint32_t kQSize = 4096;
+  uint32_t Q[kQSize];
+  uint32_t c;
+  uint32_t i;
+};
+
+
 #endif  // ifndef CCTEST_H_

test/cctest/test-global-handles.cc

@@ -25,6 +25,9 @@
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
+#include <map>
+#include <vector>
+
 #include "global-handles.h"
 
 #include "cctest.h"
@@ -315,3 +318,154 @@ TEST(ImplicitReferences) {
   ASSERT(implicit_refs->at(1)->length == 1);
   ASSERT(implicit_refs->at(1)->children[0] == g2c1.location());
 }
+
+
+static const int kBlockSize = 256;
+
+
+TEST(BlockCollection) {
+  v8::V8::Initialize();
+  Isolate* isolate = Isolate::Current();
+  GlobalHandles* global_handles = isolate->global_handles();
+  CHECK_EQ(0, global_handles->block_count());
+  CHECK_EQ(0, global_handles->global_handles_count());
+  Object* object = isolate->heap()->undefined_value();
+  const int kNumberOfBlocks = 5;
+  typedef Handle<Object> Block[kBlockSize];
+  for (int round = 0; round < 3; round++) {
+    Block blocks[kNumberOfBlocks];
+    for (int i = 0; i < kNumberOfBlocks; i++) {
+      for (int j = 0; j < kBlockSize; j++) {
+        blocks[i][j] = global_handles->Create(object);
+      }
+    }
+    CHECK_EQ(kNumberOfBlocks, global_handles->block_count());
+    for (int i = 0; i < kNumberOfBlocks; i++) {
+      for (int j = 0; j < kBlockSize; j++) {
+        global_handles->Destroy(blocks[i][j].location());
+      }
+    }
+    isolate->heap()->CollectAllAvailableGarbage("BlockCollection");
+    CHECK_EQ(0, global_handles->global_handles_count());
+    CHECK_EQ(1, global_handles->block_count());
+  }
+}
+
+
+class RandomMutationData {
+ public:
+  explicit RandomMutationData(Isolate* isolate)
+      : isolate_(isolate), weak_offset_(0) {}
+
+  void Mutate(double strong_growth_tendency,
+              double weak_growth_tendency = 0.05) {
+    for (int i = 0; i < kBlockSize * 100; i++) {
+      if (rng_.next(strong_growth_tendency)) {
+        AddStrong();
+      } else if (strong_nodes_.size() != 0) {
+        size_t to_remove = rng_.next(static_cast<int>(strong_nodes_.size()));
+        RemoveStrong(to_remove);
+      }
+      if (rng_.next(weak_growth_tendency)) AddWeak();
+      if (rng_.next(0.05)) {
+#ifdef DEBUG
+        isolate_->global_handles()->VerifyBlockInvariants();
+#endif
+      }
+      if (rng_.next(0.0001)) {
+        isolate_->heap()->PerformScavenge();
+      } else if (rng_.next(0.00003)) {
+        isolate_->heap()->CollectAllAvailableGarbage();
+      }
+      CheckSizes();
+    }
+  }
+
+  void RemoveAll() {
+    while (strong_nodes_.size() != 0) {
+      RemoveStrong(strong_nodes_.size() - 1);
+    }
+    isolate_->heap()->PerformScavenge();
+    isolate_->heap()->CollectAllAvailableGarbage();
+    CheckSizes();
+  }
+
+ private:
+  typedef std::vector<Object**> NodeVector;
+  typedef std::map<int32_t, Object**> NodeMap;
+
+  void CheckSizes() {
+    int stored_sizes =
+        static_cast<int>(strong_nodes_.size() + weak_nodes_.size());
+    CHECK_EQ(isolate_->global_handles()->global_handles_count(), stored_sizes);
+  }
+
+  void AddStrong() {
+    Object* object = isolate_->heap()->undefined_value();
+    Object** location = isolate_->global_handles()->Create(object).location();
+    strong_nodes_.push_back(location);
+  }
+
+  void RemoveStrong(size_t offset) {
+    isolate_->global_handles()->Destroy(strong_nodes_.at(offset));
+    strong_nodes_.erase(strong_nodes_.begin() + offset);
+  }
+
+  void AddWeak() {
+    v8::Isolate* isolate = reinterpret_cast<v8::Isolate*>(isolate_);
+    v8::HandleScope scope(isolate);
+    v8::Local<v8::Object> object = v8::Object::New();
+    int32_t offset = ++weak_offset_;
+    object->Set(7, v8::Integer::New(offset, isolate));
+    v8::Persistent<v8::Object> persistent(isolate, object);
+    persistent.MakeWeak(isolate, this, WeakCallback);
+    persistent.MarkIndependent();
+    Object** location = v8::Utils::OpenPersistent(persistent).location();
+    bool inserted =
+        weak_nodes_.insert(std::make_pair(offset, location)).second;
+    CHECK(inserted);
+  }
+
+  static void WeakCallback(v8::Isolate* isolate,
+                           v8::Persistent<v8::Object>* persistent,
+                           RandomMutationData* data) {
+    v8::Local<v8::Object> object =
+        v8::Local<v8::Object>::New(isolate, *persistent);
+    int32_t offset =
+        v8::Local<v8::Integer>::Cast(object->Get(7))->Int32Value();
+    Object** location = v8::Utils::OpenPersistent(persistent).location();
+    NodeMap& weak_nodes = data->weak_nodes_;
+    NodeMap::iterator it = weak_nodes.find(offset);
+    CHECK(it != weak_nodes.end());
+    CHECK(it->second == location);
+    weak_nodes.erase(it);
+    persistent->Dispose();
+  }
+
+  Isolate* isolate_;
+  RandomNumberGenerator rng_;
+  NodeVector strong_nodes_;
+  NodeMap weak_nodes_;
+  int32_t weak_offset_;
+};
+
+
+TEST(RandomMutation) {
+  v8::V8::Initialize();
+  Isolate* isolate = Isolate::Current();
+  CHECK_EQ(0, isolate->global_handles()->block_count());
+  HandleScope handle_scope(isolate);
+  v8::Context::Scope context_scope(
+      v8::Context::New(reinterpret_cast<v8::Isolate*>(isolate)));
+  RandomMutationData data(isolate);
+  // grow some
+  data.Mutate(0.65);
+  data.Mutate(0.55);
+  // balanced mutation
+  for (int i = 0; i < 3; i++) data.Mutate(0.50);
+  // shrink some
+  data.Mutate(0.45);
+  data.Mutate(0.35);
+  // clear everything
+  data.RemoveAll();
+}

test/cctest/test-strings.cc

@@ -40,58 +40,6 @@
 #include "cctest.h"
 #include "zone-inl.h"
 
-// Adapted from http://en.wikipedia.org/wiki/Multiply-with-carry
-class RandomNumberGenerator {
- public:
-  RandomNumberGenerator() {
-    init();
-  }
-
-  void init(uint32_t seed = 0x5688c73e) {
-    static const uint32_t phi = 0x9e3779b9;
-    c = 362436;
-    i = kQSize-1;
-    Q[0] = seed;
-    Q[1] = seed + phi;
-    Q[2] = seed + phi + phi;
-    for (unsigned j = 3; j < kQSize; j++) {
-      Q[j] = Q[j - 3] ^ Q[j - 2] ^ phi ^ j;
-    }
-  }
-
-  uint32_t next() {
-    uint64_t a = 18782;
-    uint32_t r = 0xfffffffe;
-    i = (i + 1) & (kQSize-1);
-    uint64_t t = a * Q[i] + c;
-    c = (t >> 32);
-    uint32_t x = static_cast<uint32_t>(t + c);
-    if (x < c) {
-      x++;
-      c++;
-    }
-    return (Q[i] = r - x);
-  }
-
-  uint32_t next(int max) {
-    return next() % max;
-  }
-
-  bool next(double threshold) {
-    ASSERT(threshold >= 0.0 && threshold <= 1.0);
-    if (threshold == 1.0) return true;
-    if (threshold == 0.0) return false;
-    uint32_t value = next() % 100000;
-    return threshold > static_cast<double>(value)/100000.0;
-  }
-
- private:
-  static const uint32_t kQSize = 4096;
-  uint32_t Q[kQSize];
-  uint32_t c;
-  uint32_t i;
-};
-
 
 using namespace v8::internal;