Initial work on computing SSA.

runtime/vm/intermediate_language.h

 // Copyright (c) 2012, 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_INTERMEDIATE_LANGUAGE_H_
 #define VM_INTERMEDIATE_LANGUAGE_H_
 
 #include "vm/allocation.h"
 #include "vm/ast.h"
 #include "vm/growable_array.h"
@@ skipping 1345 matching lines @@
   }
 
   virtual Instruction* StraightLineSuccessor() const {
     return successor_;
   }
   virtual void SetSuccessor(Instruction* instr) {
     ASSERT(successor_ == NULL);
     successor_ = instr;
   }
 
+  void InsertPhi(intptr_t variable_index) { }

[Kevin Millikin (Google), 2012/05/16 15:33:08]

This needs an implementation that adds a Phi with PredecessorCount()
uninitialized inputs.

+
  private:
   ZoneGrowableArray<BlockEntryInstr*> predecessors_;
   Instruction* successor_;
 
   DISALLOW_COPY_AND_ASSIGN(JoinEntryInstr);
 };
 
 
 class TargetEntryInstr : public BlockEntryInstr {
  public:
@@ skipping 295 matching lines @@
   const GrowableArray<BlockEntryInstr*>& block_order_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(FlowGraphVisitor);
 };
 
 
 }  // namespace dart
 
 #endif  // VM_INTERMEDIATE_LANGUAGE_H_