convert BitVector to use pointer size blocks

src/data-flow.h

Index: src/data-flow.h
diff --git a/src/data-flow.h b/src/data-flow.h
index bfd238d24ee326d52bdc902792f2d71a0ab8c59f..ac8220d22680037107626d3afe4f03bbe6d8c67b 100644
--- a/src/data-flow.h
+++ b/src/data-flow.h
@@ -39,14 +39,14 @@ class BitVector: public ZoneObject {
     }
 
    private:
-    uint32_t SkipZeroBytes(uint32_t val) {
+    uintptr_t SkipZeroBytes(uintptr_t val) {
       while ((val & 0xFF) == 0) {
         val >>= 8;
         current_ += 8;
       }
       return val;
     }
-    uint32_t SkipZeroBits(uint32_t val) {
+    uintptr_t SkipZeroBits(uintptr_t val) {
       while ((val & 0x1) == 0) {
         val >>= 1;
         current_++;
@@ -56,16 +56,20 @@ class BitVector: public ZoneObject {
 
     BitVector* target_;
     int current_index_;
-    uint32_t current_value_;
+    uintptr_t current_value_;
     int current_;
 
     friend class BitVector;
   };
 
+  static const int kDataBits = kPointerSize * 8;
+  static const int kDataBitShift = kPointerSize == 8 ? 6 : 5;
+  static const uintptr_t kOne = 1;  // This saves some static_casts.
+
   BitVector(int length, Zone* zone)
       : length_(length),
         data_length_(SizeFor(length)),
-        data_(zone->NewArray<uint32_t>(data_length_)) {
+        data_(zone->NewArray<uintptr_t>(data_length_)) {
     DCHECK(length > 0);
     Clear();
   }
@@ -73,18 +77,11 @@ class BitVector: public ZoneObject {
   BitVector(const BitVector& other, Zone* zone)
       : length_(other.length()),
         data_length_(SizeFor(length_)),
-        data_(zone->NewArray<uint32_t>(data_length_)) {
+        data_(zone->NewArray<uintptr_t>(data_length_)) {
     CopyFrom(other);
   }
 
-  static int SizeFor(int length) {
-    return 1 + ((length - 1) / 32);
-  }
-
-  BitVector& operator=(const BitVector& rhs) {
-    if (this != &rhs) CopyFrom(rhs);
-    return *this;
-  }
+  static int SizeFor(int length) { return 1 + ((length - 1) / kDataBits); }
 
   void CopyFrom(const BitVector& other) {
     DCHECK(other.length() <= length());
@@ -98,18 +95,18 @@ class BitVector: public ZoneObject {
 
   bool Contains(int i) const {
     DCHECK(i >= 0 && i < length());
-    uint32_t block = data_[i / 32];
-    return (block & (1U << (i % 32))) != 0;
+    uintptr_t block = data_[i / kDataBits];
+    return (block & (kOne << (i % kDataBits))) != 0;
   }
 
   void Add(int i) {
     DCHECK(i >= 0 && i < length());
-    data_[i / 32] |= (1U << (i % 32));
+    data_[i / kDataBits] |= (kOne << (i % kDataBits));
   }
 
   void Remove(int i) {
     DCHECK(i >= 0 && i < length());
-    data_[i / 32] &= ~(1U << (i % 32));
+    data_[i / kDataBits] &= ~(kOne << (i % kDataBits));
   }
 
   void Union(const BitVector& other) {
@@ -123,7 +120,7 @@ class BitVector: public ZoneObject {
     DCHECK(other.length() == length());
     bool changed = false;
     for (int i = 0; i < data_length_; i++) {
-      uint32_t old_data = data_[i];
+      uintptr_t old_data = data_[i];
       data_[i] |= other.data_[i];
       if (data_[i] != old_data) changed = true;
     }
@@ -141,7 +138,7 @@ class BitVector: public ZoneObject {
     DCHECK(other.length() == length());
     bool changed = false;
     for (int i = 0; i < data_length_; i++) {
-      uint32_t old_data = data_[i];
+      uintptr_t old_data = data_[i];
       data_[i] &= other.data_[i];
       if (data_[i] != old_data) changed = true;
     }
@@ -184,9 +181,11 @@ class BitVector: public ZoneObject {
 #endif
 
  private:
-  int length_;
-  int data_length_;
-  uint32_t* data_;
+  const int length_;
+  const int data_length_;
+  uintptr_t* const data_;
+
+  DISALLOW_COPY_AND_ASSIGN(BitVector);
 };