[turbofan] Greedy: split around calls heuristic.

src/compiler/greedy-allocator.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_GREEDY_ALLOCATOR_H_
 #define V8_GREEDY_ALLOCATOR_H_
 
 #include "src/compiler/coalesced-live-ranges.h"
 #include "src/compiler/register-allocator.h"
 #include "src/zone-containers.h"
@@ skipping 107 matching lines @@
   float GetAllocatedRangeWeight(float candidate_weight);
 
   // Returns kInvalidWeight if there are no conflicts, or the largest weight of
   // a range conflicting with the given range, at the given register.
   float GetMaximumConflictingWeight(unsigned reg_id,
                                     const LiveRange* range) const;
 
   // This is the extension point for splitting heuristics.
   void SplitOrSpillBlockedRange(LiveRange* range);
 
+  // Find a good position where to fill, after a range was spilled after a call.
+  LifetimePosition FindSplitPositionAfterCall(const LiveRange* range,
+                                              int call_index);
+  // Split a range around all calls it passes over. Returns true if any changes
+  // were made, or false if no calls were found.
+  bool TrySplitAroundCalls(LiveRange* range);
+
+  // Finds the first call instruction in the path of this range. Splits before
+  // and requeues that segment (if any), spills the section over the call, and
+  // returns the section after the call. The return is:
+  // - same range, if no call was found
+  // - nullptr, if the range finished at the call and there's no "after the
+  //   call" portion.
+  // - the portion after the call.
+  LiveRange* GetRemainderAfterSplittingAroundFirstCall(LiveRange* range);
+
   // Necessary heuristic: spill when all else failed.
   void SpillRangeAsLastResort(LiveRange* range);
 
   void AssignRangeToRegister(int reg_id, LiveRange* range);
 
   Zone* local_zone_;
   ZoneVector<CoalescedLiveRanges*> allocations_;
   AllocationScheduler scheduler_;
   DISALLOW_COPY_AND_ASSIGN(GreedyAllocator);
 };
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 #endif  // V8_GREEDY_ALLOCATOR_H_