Implementation of a fixed-size bit vector.

This is a basic implementation bit vector containing an fixed 
arbitrary number of bits.

Review URL: http://codereview.chromium.org/660321

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@3991 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/data-flow.h

@@ -28,12 +28,73 @@
 #ifndef V8_DATAFLOW_H_
 #define V8_DATAFLOW_H_
 
+#include "v8.h"
+
 #include "ast.h"
 #include "compiler.h"
 
 namespace v8 {
 namespace internal {
 
+class BitVector {
+ public:
+  explicit BitVector(int length) : length_(length) {
+    ASSERT(length > 0);
+    bits_ = Vector<uint32_t>::New(1 + length / 32);
+    for (int i = 0; i < bits_.length(); i++) {
+      bits_[i] = 0;
+    }
+  }
+
+  ~BitVector() { bits_.Dispose(); }
+
+  void CopyFrom(const BitVector& other) {
+    ASSERT(other.length() == length());
+    for (int i = 0; i < bits_.length(); i++) {
+      bits_[i] = other.bits_[i];
+    }
+  }
+
+  bool Contains(int i) {
+    ASSERT(i >= 0 && i < length());
+    uint32_t block = bits_[i / 32];
+    return (block & (1U << (i % 32))) != 0;
+  }
+
+  void Add(int i) {
+    ASSERT(i >= 0 && i < length());
+    bits_[i / 32] |= (1U << (i % 32));
+  }
+
+  void Remove(int i) {
+    ASSERT(i >= 0 && i < length());
+    bits_[i / 32] &= ~(1U << (i % 32));
+  }
+
+  void Union(const BitVector& other) {
+    ASSERT(other.length() == length());
+    for (int i = 0; i < bits_.length(); i++) {
+      bits_[i] |= other.bits_[i];
+    }
+  }
+
+  void Intersect(const BitVector& other) {
+    ASSERT(other.length() == length());
+    for (int i = 0; i < bits_.length(); i++) {
+      bits_[i] &= other.bits_[i];
+    }
+  }
+
+  int length() const { return length_; }
+
+ private:
+  int length_;
+  Vector<uint32_t> bits_;
+
+  DISALLOW_COPY_AND_ASSIGN(BitVector);
+};
+
+
 // This class is used to number all expressions in the AST according to
 // their evaluation order (post-order left-to-right traversal).
 class AstLabeler: public AstVisitor {

test/cctest/SConscript

@@ -40,6 +40,7 @@ SOURCES = {
     'test-ast.cc',
     'test-compiler.cc',
     'test-conversions.cc',
+    'test-dataflow.cc',
     'test-debug.cc',
     'test-decls.cc',
     'test-flags.cc',

test/cctest/test-dataflow.cc

+// Copyright 2010 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+//       notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+//       copyright notice, this list of conditions and the following
+//       disclaimer in the documentation and/or other materials provided
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (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 <stdlib.h>
+
+#include "v8.h"
+
+#include "data-flow.h"
+#include "cctest.h"
+
+using namespace v8::internal;
+
+TEST(BitVector) {
+  {
+    BitVector v(15);
+    v.Add(1);
+    CHECK(v.Contains(1));
+    v.Remove(0);
+    CHECK(!v.Contains(0));
+    v.Add(0);
+    v.Add(1);
+    BitVector w(15);
+    w.Add(1);
+    v.Intersect(w);
+    CHECK(!v.Contains(0));
+    CHECK(v.Contains(1));
+  }
+
+  {
+    BitVector v(15);
+    v.Add(0);
+    BitVector w(15);
+    w.Add(1);
+    v.Union(w);
+    CHECK(v.Contains(0));
+    CHECK(v.Contains(1));
+  }
+
+  {
+    BitVector v(35);
+    v.Add(0);
+    BitVector w(35);
+    w.Add(33);
+    v.Union(w);
+    CHECK(v.Contains(0));
+    CHECK(v.Contains(33));
+  }
+
+  {
+    BitVector v(35);
+    v.Add(32);
+    v.Add(33);
+    BitVector w(35);
+    w.Add(33);
+    v.Intersect(w);
+    CHECK(!v.Contains(32));
+    CHECK(v.Contains(33));
+    BitVector r(35);
+    r.CopyFrom(v);
+    CHECK(!r.Contains(32));
+    CHECK(r.Contains(33));
+  }
+}