Convert some compiler passes to preserve valid def-use chains.

runtime/vm/flow_graph_optimizer.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_FLOW_GRAPH_OPTIMIZER_H_
 #define VM_FLOW_GRAPH_OPTIMIZER_H_
 
 #include "vm/intermediate_language.h"
 #include "vm/flow_graph.h"
 
@@ skipping 29 matching lines @@
   virtual void VisitStaticCall(StaticCallInstr* instr);
   virtual void VisitInstanceCall(InstanceCallInstr* instr);
   virtual void VisitRelationalOp(RelationalOpInstr* instr);
   virtual void VisitEqualityCompare(EqualityCompareInstr* instr);
   virtual void VisitBranch(BranchInstr* instr);
   virtual void VisitStrictCompare(StrictCompareInstr* instr);
 
   void InsertBefore(Instruction* next,
                     Instruction* instr,
                     Environment* env,
-                    Definition::UseKind use_kind);
+                    Definition::UseKind use_kind) {
+    flow_graph_->InsertBefore(next, instr, env, use_kind);
+  }
 
  private:
   // Attempt to build ICData for call using propagated class-ids.
   bool TryCreateICData(InstanceCallInstr* call);
 
   void SpecializePolymorphicInstanceCall(PolymorphicInstanceCallInstr* call);
 
   intptr_t PrepareIndexedOp(InstanceCallInstr* call,
                             intptr_t class_id,
-                            Value** array,
-                            Value** index);
+                            Definition** array,
+                            Definition** index);
   bool TryReplaceWithStoreIndexed(InstanceCallInstr* call);
   bool TryReplaceWithLoadIndexed(InstanceCallInstr* call);
 
   bool TryReplaceWithBinaryOp(InstanceCallInstr* call, Token::Kind op_kind);
   bool TryReplaceWithUnaryOp(InstanceCallInstr* call, Token::Kind op_kind);
 
   bool TryInlineInstanceGetter(InstanceCallInstr* call);
   bool TryInlineInstanceSetter(InstanceCallInstr* call,
                                const ICData& unary_ic_data);
 
   bool TryInlineInstanceMethod(InstanceCallInstr* call);
   void ReplaceWithInstanceOf(InstanceCallInstr* instr);
 
   LoadIndexedInstr* BuildStringCharCodeAt(InstanceCallInstr* call,
                                           intptr_t cid);
 
   LoadIndexedInstr* BuildByteArrayViewLoad(InstanceCallInstr* call,
                                            intptr_t receiver_cid,
                                            intptr_t view_cid);
 
-  void AddCheckClass(InstanceCallInstr* call, Value* value);
+  // Insert a check of 'to_check' determined by 'unary_checks'.  If the
+  // check fails it will deoptimize to 'deopt_id' using the deoptimization
+  // environment 'deopt_environment'.  The check is inserted immediately
+  // before 'insert_before'.
+  void AddCheckClass(Definition* to_check,
+                     const ICData& unary_checks,
+                     intptr_t deopt_id,
+                     Environment* deopt_environment,
+                     Instruction* insert_before);
 
-  void InsertAfter(Instruction* prev,
-                   Instruction* instr,
-                   Environment* env,
-                   Definition::UseKind use_kind);
+  // Add a class check for a call's first argument immediately before the
+  // call, using the call's IC data to determine the check, and the call's
+  // deopt ID and deoptimization environment if the check fails.
+  void AddReceiverCheck(InstanceCallInstr* call);
+
+  void ReplaceCall(Definition* call, Definition* replacement);
 
   void InsertConversionsFor(Definition* def);
 
   void InsertConversion(Representation from,
                         Representation to,
                         Value* use,
                         Instruction* insert_before,
                         Instruction* deopt_target);
 
   bool InstanceCallNeedsClassCheck(InstanceCallInstr* call) const;
   bool MethodExtractorNeedsClassCheck(InstanceCallInstr* call) const;
 
   void InlineImplicitInstanceGetter(InstanceCallInstr* call);
   void InlineArrayLengthGetter(InstanceCallInstr* call,
                                intptr_t length_offset,
                                bool is_immutable,
                                MethodRecognizer::Kind kind);
   void InlineGrowableArrayCapacityGetter(InstanceCallInstr* call);
   void InlineStringLengthGetter(InstanceCallInstr* call);
   void InlineStringIsEmptyGetter(InstanceCallInstr* call);
 
   RawBool* InstanceOfAsBool(const ICData& ic_data,
                             const AbstractType& type) const;
 
   void ReplaceWithMathCFunction(InstanceCallInstr* call,
                                 MethodRecognizer::Kind recognized_kind);
 
+  void HandleRelationalOp(RelationalOpInstr* comp);
+
+  // Visit an equality compare.  The current instruction can be the
+  // comparison itself or a branch on the comparison.
+  template <typename T>
+  void HandleEqualityCompare(EqualityCompareInstr* comp,
+                             T current_instruction);
+
   FlowGraph* flow_graph_;
 
   DISALLOW_COPY_AND_ASSIGN(FlowGraphOptimizer);
 };
 
 
 class ParsedFunction;
 
 
 // Loop invariant code motion.
@@ skipping 85 matching lines @@
 
   // Worklists of blocks and definitions.
   GrowableArray<BlockEntryInstr*> block_worklist_;
   GrowableArray<Definition*> definition_worklist_;
 };
 
 
 }  // namespace dart
 
 #endif  // VM_FLOW_GRAPH_OPTIMIZER_H_