[turbofan] Live Range unit tests

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) {}
+  explicit TestRangeBuilder(Zone* zone)
+      : id_(-1), pairs_(), uses_(), 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(); }
+  TestRangeBuilder& AddUse(int pos) {
+    uses_.insert(pos);
+    return *this;
+  }
 
-  LiveRange* Build() {
+  TopLevelLiveRange* Build(int start, int end) {
+    return Add(start, end).Build();
+  }
+
+  TopLevelLiveRange* 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_);
     }
+    for (int pos : uses_) {
+      UsePosition* use_position =
+          new (zone_) UsePosition(LifetimePosition::FromInt(pos), nullptr,
+                                  nullptr, UsePositionHintType::kNone);
+      range->AddUsePosition(use_position);
+    }
 
     pairs_.clear();
     return range;
   }
 
  private:
   typedef std::pair<int, int> Interval;
   typedef std::vector<Interval> IntervalList;
   int id_;
   IntervalList pairs_;
+  std::set<int> uses_;
   Zone* zone_;
 };
 
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_LIVE_RANGE_BUILDER_H_