Refactor ArenaBitVector to create more general BitVector

Change-Id: Ib26f2884de9ce7d620048bdf5ed6dec639622e41
diff --git a/compiler/dex/arena_bit_vector.cc b/compiler/dex/arena_bit_vector.cc
index b921f61..b567ae8 100644
--- a/compiler/dex/arena_bit_vector.cc
+++ b/compiler/dex/arena_bit_vector.cc
@@ -19,119 +19,29 @@
 
 namespace art {
 
-// TODO: profile to make sure this is still a win relative to just using shifted masks.
-static uint32_t check_masks[32] = {
-  0x00000001, 0x00000002, 0x00000004, 0x00000008, 0x00000010,
-  0x00000020, 0x00000040, 0x00000080, 0x00000100, 0x00000200,
-  0x00000400, 0x00000800, 0x00001000, 0x00002000, 0x00004000,
-  0x00008000, 0x00010000, 0x00020000, 0x00040000, 0x00080000,
-  0x00100000, 0x00200000, 0x00400000, 0x00800000, 0x01000000,
-  0x02000000, 0x04000000, 0x08000000, 0x10000000, 0x20000000,
-  0x40000000, 0x80000000 };
+class ArenaBitVectorAllocator : public Allocator {
+ public:
+  explicit ArenaBitVectorAllocator(ArenaAllocator* arena) : arena_(arena) {}
+  ~ArenaBitVectorAllocator() {}
+
+  virtual void* Alloc(size_t size) {
+    return arena_->Alloc(size, ArenaAllocator::kAllocGrowableBitMap);
+  }
+
+  virtual void Free(void*) {}  // Nop.
+
+  static void* operator new(size_t size, ArenaAllocator* arena) {
+    return arena->Alloc(sizeof(ArenaBitVectorAllocator), ArenaAllocator::kAllocGrowableBitMap);
+  }
+  static void operator delete(void* p) {}  // Nop.
+
+ private:
+  ArenaAllocator* arena_;
+  DISALLOW_COPY_AND_ASSIGN(ArenaBitVectorAllocator);
+};
 
 ArenaBitVector::ArenaBitVector(ArenaAllocator* arena, unsigned int start_bits,
                                bool expandable, OatBitMapKind kind)
-  :  arena_(arena),
-     expandable_(expandable),
-     kind_(kind),
-     storage_size_((start_bits + 31) >> 5),
-     storage_(static_cast<uint32_t*>(arena_->Alloc(storage_size_ * sizeof(uint32_t),
-                                                   ArenaAllocator::kAllocGrowableBitMap))) {
-  DCHECK_EQ(sizeof(storage_[0]), 4U);    // Assuming 32-bit units.
-}
-
-/*
- * Determine whether or not the specified bit is set.
- */
-bool ArenaBitVector::IsBitSet(unsigned int num) {
-  DCHECK_LT(num, storage_size_ * sizeof(uint32_t) * 8);
-
-  unsigned int val = storage_[num >> 5] & check_masks[num & 0x1f];
-  return (val != 0);
-}
-
-// Mark all bits bit as "clear".
-void ArenaBitVector::ClearAllBits() {
-  memset(storage_, 0, storage_size_ * sizeof(uint32_t));
-}
-
-// Mark the specified bit as "set".
-/*
- * TUNING: this could have pathologically bad growth/expand behavior.  Make sure we're
- * not using it badly or change resize mechanism.
- */
-void ArenaBitVector::SetBit(unsigned int num) {
-  if (num >= storage_size_ * sizeof(uint32_t) * 8) {
-    DCHECK(expandable_) << "Attempted to expand a non-expandable bitmap to position " << num;
-
-    /* Round up to word boundaries for "num+1" bits */
-    unsigned int new_size = (num + 1 + 31) >> 5;
-    DCHECK_GT(new_size, storage_size_);
-    uint32_t *new_storage =
-        static_cast<uint32_t*>(arena_->Alloc(new_size * sizeof(uint32_t),
-                                             ArenaAllocator::kAllocGrowableBitMap));
-    memcpy(new_storage, storage_, storage_size_ * sizeof(uint32_t));
-    // Zero out the new storage words.
-    memset(&new_storage[storage_size_], 0, (new_size - storage_size_) * sizeof(uint32_t));
-    // TOTO: collect stats on space wasted because of resize.
-    storage_ = new_storage;
-    storage_size_ = new_size;
-  }
-
-  storage_[num >> 5] |= check_masks[num & 0x1f];
-}
-
-// Mark the specified bit as "unset".
-void ArenaBitVector::ClearBit(unsigned int num) {
-  DCHECK_LT(num, storage_size_ * sizeof(uint32_t) * 8);
-  storage_[num >> 5] &= ~check_masks[num & 0x1f];
-}
-
-// Intersect with another bit vector.  Sizes and expandability must be the same.
-void ArenaBitVector::Intersect(const ArenaBitVector* src) {
-  DCHECK_EQ(storage_size_, src->GetStorageSize());
-  DCHECK_EQ(expandable_, src->IsExpandable());
-  for (unsigned int idx = 0; idx < storage_size_; idx++) {
-    storage_[idx] &= src->GetRawStorageWord(idx);
-  }
-}
-
-/*
- * Union with another bit vector.  Sizes and expandability must be the same.
- */
-void ArenaBitVector::Union(const ArenaBitVector* src) {
-  DCHECK_EQ(storage_size_, src->GetStorageSize());
-  DCHECK_EQ(expandable_, src->IsExpandable());
-  for (unsigned int idx = 0; idx < storage_size_; idx++) {
-    storage_[idx] |= src->GetRawStorageWord(idx);
-  }
-}
-
-// Count the number of bits that are set.
-int ArenaBitVector::NumSetBits() {
-  unsigned int count = 0;
-
-  for (unsigned int word = 0; word < storage_size_; word++) {
-    count += __builtin_popcount(storage_[word]);
-  }
-  return count;
-}
-
-/*
- * Mark specified number of bits as "set". Cannot set all bits like ClearAll
- * since there might be unused bits - setting those to one will confuse the
- * iterator.
- */
-void ArenaBitVector::SetInitialBits(unsigned int num_bits) {
-  DCHECK_LE(((num_bits + 31) >> 5), storage_size_);
-  unsigned int idx;
-  for (idx = 0; idx < (num_bits >> 5); idx++) {
-    storage_[idx] = -1;
-  }
-  unsigned int rem_num_bits = num_bits & 0x1f;
-  if (rem_num_bits) {
-    storage_[idx] = (1 << rem_num_bits) - 1;
-  }
-}
+  :  BitVector(start_bits, expandable, new (arena) ArenaBitVectorAllocator(arena)), kind_(kind) {}
 
 }  // namespace art
diff --git a/compiler/dex/arena_bit_vector.h b/compiler/dex/arena_bit_vector.h
index 53e6eb6..7d2f3ff 100644
--- a/compiler/dex/arena_bit_vector.h
+++ b/compiler/dex/arena_bit_vector.h
@@ -17,109 +17,28 @@
 #ifndef ART_COMPILER_DEX_ARENA_BIT_VECTOR_H_
 #define ART_COMPILER_DEX_ARENA_BIT_VECTOR_H_
 
-#include <stdint.h>
-#include <stddef.h>
-#include "compiler_enums.h"
 #include "arena_allocator.h"
+#include "compiler_enums.h"
+#include "utils/bit_vector.h"
 
 namespace art {
 
 /*
- * Expanding bitmap, used for tracking resources.  Bits are numbered starting
- * from zero.  All operations on a BitVector are unsynchronized.
+ * A BitVector implementation that uses Arena allocation.
  */
-class ArenaBitVector {
+class ArenaBitVector : public BitVector {
   public:
-    class Iterator {
-      public:
-        explicit Iterator(ArenaBitVector* bit_vector)
-          : p_bits_(bit_vector),
-            bit_storage_(bit_vector->GetRawStorage()),
-            bit_index_(0),
-            bit_size_(p_bits_->storage_size_ * sizeof(uint32_t) * 8) {}
-
-        // Return the position of the next set bit.  -1 means end-of-element reached.
-        int32_t Next() {
-          // Did anything obviously change since we started?
-          DCHECK_EQ(bit_size_, p_bits_->GetStorageSize() * sizeof(uint32_t) * 8);
-          DCHECK_EQ(bit_storage_, p_bits_->GetRawStorage());
-
-          if (UNLIKELY(bit_index_ >= bit_size_)) return -1;
-
-          uint32_t word_index = bit_index_ / 32;
-          uint32_t word = bit_storage_[word_index];
-          // Mask out any bits in the first word we've already considered.
-          word >>= bit_index_ & 0x1f;
-          if (word == 0) {
-            bit_index_ &= ~0x1f;
-            do {
-              word_index++;
-              if (UNLIKELY((word_index * 32) >= bit_size_)) {
-                bit_index_ = bit_size_;
-                return -1;
-              }
-              word = bit_storage_[word_index];
-              bit_index_ += 32;
-            } while (word == 0);
-          }
-          bit_index_ += CTZ(word) + 1;
-          return bit_index_ - 1;
-        }
-
-        static void* operator new(size_t size, ArenaAllocator* arena) {
-          return arena->Alloc(sizeof(ArenaBitVector::Iterator),
-                              ArenaAllocator::kAllocGrowableBitMap);
-        };
-        static void operator delete(void* p) {}  // Nop.
-
-      private:
-        ArenaBitVector* const p_bits_;
-        uint32_t* const bit_storage_;
-        uint32_t bit_index_;              // Current index (size in bits).
-        const uint32_t bit_size_;       // Size of vector in bits.
-    };
-
     ArenaBitVector(ArenaAllocator* arena, uint32_t start_bits, bool expandable,
                    OatBitMapKind kind = kBitMapMisc);
     ~ArenaBitVector() {}
 
-    static void* operator new(size_t size, ArenaAllocator* arena) {
-      return arena->Alloc(sizeof(ArenaBitVector), ArenaAllocator::kAllocGrowableBitMap);
-    }
-    static void operator delete(void* p) {}  // Nop.
-
-    void SetBit(uint32_t num);
-    void ClearBit(uint32_t num);
-    void MarkAllBits(bool set);
-    void DebugBitVector(char* msg, int length);
-    bool IsBitSet(uint32_t num);
-    void ClearAllBits();
-    void SetInitialBits(uint32_t num_bits);
-    void Copy(ArenaBitVector* src) {
-      memcpy(storage_, src->GetRawStorage(), sizeof(uint32_t) * storage_size_);
-    }
-    void Intersect(const ArenaBitVector* src2);
-    void Union(const ArenaBitVector* src);
-    // Are we equal to another bit vector?  Note: expandability attributes must also match.
-    bool Equal(const ArenaBitVector* src) {
-      return (storage_size_ == src->GetStorageSize()) &&
-        (expandable_ == src->IsExpandable()) &&
-        (memcmp(storage_, src->GetRawStorage(), storage_size_ * 4) == 0);
-    }
-    int32_t NumSetBits();
-
-    uint32_t GetStorageSize() const { return storage_size_; }
-    bool IsExpandable() const { return expandable_; }
-    uint32_t GetRawStorageWord(size_t idx) const { return storage_[idx]; }
-    uint32_t* GetRawStorage() { return storage_; }
-    const uint32_t* GetRawStorage() const { return storage_; }
+  static void* operator new(size_t size, ArenaAllocator* arena) {
+     return arena->Alloc(sizeof(ArenaBitVector), ArenaAllocator::kAllocGrowableBitMap);
+  }
+  static void operator delete(void* p) {}  // Nop.
 
   private:
-    ArenaAllocator* const arena_;
-    const bool expandable_;         // expand bitmap if we run out?
-    const OatBitMapKind kind_;      // for memory use tuning.
-    uint32_t   storage_size_;       // current size, in 32-bit words.
-    uint32_t*  storage_;
+    const OatBitMapKind kind_;      // for memory use tuning. TODO: currently unused.
 };
 
 
diff --git a/compiler/dex/ssa_transformation.cc b/compiler/dex/ssa_transformation.cc
index eb0d412..b6c8922 100644
--- a/compiler/dex/ssa_transformation.cc
+++ b/compiler/dex/ssa_transformation.cc
@@ -183,7 +183,7 @@
   ClearAllVisitedFlags();
   std::vector<std::pair<BasicBlock*, ArenaBitVector::Iterator*> > work_stack;
   bb->visited = true;
-  work_stack.push_back(std::make_pair(bb, new (arena_) ArenaBitVector::Iterator(bb->i_dominated)));
+  work_stack.push_back(std::make_pair(bb, bb->i_dominated->GetIterator()));
   while (!work_stack.empty()) {
     const std::pair<BasicBlock*, ArenaBitVector::Iterator*>& curr = work_stack.back();
     BasicBlock* curr_bb = curr.first;
@@ -196,7 +196,7 @@
       BasicBlock* new_bb = GetBasicBlock(bb_idx);
       new_bb->visited = true;
       work_stack.push_back(
-          std::make_pair(new_bb, new (arena_) ArenaBitVector::Iterator(new_bb->i_dominated)));
+          std::make_pair(new_bb, new_bb->i_dominated->GetIterator()));
     } else {
       // no successor/next
       if (curr_bb->id != NullBasicBlockId) {