Reland of [ignition/turbo] Perform liveness analysis on the bytecodes

src/compiler/bytecode-liveness-map.cc

Index: src/compiler/bytecode-liveness-map.cc
diff --git a/src/compiler/bytecode-liveness-map.cc b/src/compiler/bytecode-liveness-map.cc
new file mode 100644
index 0000000000000000000000000000000000000000..899e155b888d2620962eb5c66ebffcde0520dd92
--- /dev/null
+++ b/src/compiler/bytecode-liveness-map.cc
@@ -0,0 +1,41 @@
+// Copyright 2016 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "src/compiler/bytecode-liveness-map.h"
+
+namespace v8 {
+namespace internal {
+namespace compiler {
+
+Liveness::Liveness(int size, Zone* zone)
+    : in(new (zone) BitVector(size, zone)),
+      out(new (zone) BitVector(size, zone)) {}
+
+BytecodeLivenessMap::BytecodeLivenessMap(int bytecode_size, Zone* zone)
+    : liveness_map_(base::bits::RoundUpToPowerOfTwo32(bytecode_size / 4 + 1),
+                    base::KeyEqualityMatcher<int>(),
+                    ZoneAllocationPolicy(zone)) {}
+
+uint32_t OffsetHash(int offset) { return offset; }
+
+Liveness& BytecodeLivenessMap::InitializeLiveness(int offset, int size,
+                                                  Zone* zone) {
+  return liveness_map_
+      .LookupOrInsert(offset, OffsetHash(offset),
+                      [&]() { return Liveness(size, zone); },
+                      ZoneAllocationPolicy(zone))
+      ->value;
+}
+
+Liveness& BytecodeLivenessMap::GetLiveness(int offset) {
+  return liveness_map_.Lookup(offset, OffsetHash(offset))->value;
+}
+
+const Liveness& BytecodeLivenessMap::GetLiveness(int offset) const {
+  return liveness_map_.Lookup(offset, OffsetHash(offset))->value;
+}
+
+}  // namespace compiler
+}  // namespace internal
+}  // namespace v8