[turbofan] Factored out the test live range builder.

test/unittests/compiler/live-range-builder.h

+// Copyright 2015 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.
+
+#ifndef V8_LIVE_RANGE_BUILDER_H_
+#define V8_LIVE_RANGE_BUILDER_H_
+
+#include "src/compiler/register-allocator.h"
+
+namespace v8 {
+namespace internal {
+namespace compiler {
+
+
+// Utility offering shorthand syntax for building up a range by providing its ID
+// and pairs (start, end) specifying intervals. Circumvents current incomplete
+// support for C++ features such as instantiation lists, on OS X and Android.
+class TestRangeBuilder {
+ public:
+  explicit TestRangeBuilder(Zone* zone) : id_(-1), pairs_(), zone_(zone) {}
+
+  TestRangeBuilder& Id(int id) {
+    id_ = id;
+    return *this;
+  }
+  TestRangeBuilder& Add(int start, int end) {
+    pairs_.push_back({start, end});
+    return *this;
+  }
+
+  LiveRange* Build(int start, int end) { return Add(start, end).Build(); }
+
+  LiveRange* Build() {
+    TopLevelLiveRange* range =
+        new (zone_) TopLevelLiveRange(id_, MachineType::kRepTagged);
+    // Traverse the provided interval specifications backwards, because that is
+    // what LiveRange expects.
+    for (int i = static_cast<int>(pairs_.size()) - 1; i >= 0; --i) {
+      Interval pair = pairs_[i];
+      LifetimePosition start = LifetimePosition::FromInt(pair.first);
+      LifetimePosition end = LifetimePosition::FromInt(pair.second);
+      CHECK(start < end);
+      range->AddUseInterval(start, end, zone_);
+    }
+
+    pairs_.clear();
+    return range;
+  }
+
+ private:
+  typedef std::pair<int, int> Interval;
+  typedef std::vector<Interval> IntervalList;
+  int id_;
+  IntervalList pairs_;
+  Zone* zone_;
+};
+
+
+}  // namespace compiler
+}  // namespace internal
+}  // namespace v8
+
+#endif  // V8_LIVE_RANGE_BUILDER_H_