Implement a variation of scalar replacement for non-escaping allocations.

runtime/vm/flow_graph_allocator.h

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef VM_FLOW_GRAPH_ALLOCATOR_H_
 #define VM_FLOW_GRAPH_ALLOCATOR_H_
 
 #include "vm/flow_graph.h"
 #include "vm/growable_array.h"
 #include "vm/intermediate_language.h"
@@ skipping 48 matching lines @@
   explicit FlowGraphAllocator(const FlowGraph& flow_graph);
 
   void AllocateRegisters();
 
   // Map a virtual register number to its live range.
   LiveRange* GetLiveRange(intptr_t vreg);
 
  private:
   void CollectRepresentations();
 
-  // Eliminate unnecessary environments from the IL.
-  void EliminateEnvironments();
-
   // Visit blocks in the code generation order (reverse post order) and
   // linearly assign consequent lifetime positions to every instruction.
   // We assign position as follows:
   //
   //    2 * n     - even position corresponding to instruction's start;
   //
   //    2 * n + 1 - odd position corresponding to instruction's end;
   //
   // Having two positions per instruction allows us to capture non-trivial
   // shapes of use intervals: e.g. by placing a use at the start or the
@@ skipping 18 matching lines @@
   void DiscoverLoops();
 
   LiveRange* MakeLiveRangeForTemporary();
 
   // Visit instructions in the postorder and build live ranges for
   // all SSA values.
   void BuildLiveRanges();
   Instruction* ConnectOutgoingPhiMoves(BlockEntryInstr* block,
                                        BitVector* interference_set);
   void ProcessEnvironmentUses(BlockEntryInstr* block, Instruction* current);
+  void ProcessMaterializationUses(BlockEntryInstr* block,
+                                  const intptr_t block_start_pos,
+                                  const intptr_t use_pos,
+                                  MaterializeObjectInstr* mat);
   void ProcessOneInstruction(BlockEntryInstr* block,
                              Instruction* instr,
                              BitVector* interference_set);
   void ConnectIncomingPhiMoves(BlockEntryInstr* block);
   void BlockLocation(Location loc, intptr_t from, intptr_t to);
   void BlockRegisterLocation(Location loc,
                              intptr_t from,
                              intptr_t to,
                              bool* blocked_registers,
                              LiveRange** blocking_ranges);
@@ skipping 521 matching lines @@
 
   AllocationFinger finger_;
 
   DISALLOW_COPY_AND_ASSIGN(LiveRange);
 };
 
 
 }  // namespace dart
 
 #endif  // VM_FLOW_GRAPH_ALLOCATOR_H_