Automatically assign temporary indices to definitions in the IL.

runtime/vm/flow_graph_builder.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_BUILDER_H_
 #define VM_FLOW_GRAPH_BUILDER_H_
 
 #include "vm/allocation.h"
 #include "vm/ast.h"
 #include "vm/growable_array.h"
@@ skipping 97 matching lines @@
 
   // Append a 'while loop' test and back edge to this graph, depending on
   // which parts are reachable.  Afterward, the graph exit is the false
   // successor of the loop condition.
   void TieLoop(const TestGraphVisitor& test_fragment,
                const EffectGraphVisitor& body_fragment);
 
  protected:
   // Helpers for translating parts of the AST.
   void TranslateArgumentList(const ArgumentListNode& node,
-                             intptr_t next_temp_index,
                              ZoneGrowableArray<Value*>* values);
 
   // Build the load part of a instance field increment.  Translates the
   // receiver and loads the value.  The receiver will be returned in the
   // output parameter 'receiver'.
   Definition* BuildIncrOpFieldLoad(IncrOpInstanceFieldNode* node,
                                    Value** receiver);
 
   // Build the load part of an indexed increment.  Translates the receiver
   // and index and loads the value.  The receiver will be returned in the
@@ skipping 15 matching lines @@
   Definition* BuildFactoryTypeArguments(ConstructorCallNode* node);
 
   // Creates a possibly uninstantiated type argument vector and the type
   // argument vector of the instantiator (two values in 'args') used in
   // preparation of a constructor call.
   // May be called only if allocating an object of a parameterized class.
   void BuildConstructorTypeArguments(ConstructorCallNode* node,
                                      ZoneGrowableArray<Value*>* args);
 
   // Returns the value of the type arguments of the instantiator.
-  Value* BuildInstantiatorTypeArguments(intptr_t token_index,
-                                        intptr_t start_index);
+  Value* BuildInstantiatorTypeArguments(intptr_t token_index);
 
   // Perform a type check on the given value.
   void BuildAssertAssignable(intptr_t token_index,
                              Value* value,
                              const AbstractType& dst_type,
-                             const String& dst_name,
-                             intptr_t start_index);
+                             const String& dst_name);
 
   // Perform a type check on the given value and return it.
   Value* BuildAssignableValue(AstNode* value_node,
                               Value* value,
                               const AbstractType& dst_type,
-                              const String& dst_name,
-                              intptr_t start_index);
+                              const String& dst_name);
 
   virtual void BuildInstanceOf(ComparisonNode* node);
 
   bool MustSaveRestoreContext(SequenceNode* node) const;
 
   // Moves parent context into the context register.
   void UnchainContext();
 
   void CloseFragment() { exit_ = NULL; }
   intptr_t AllocateTempIndex() { return temp_index_++; }
-  void DeallocateTempIndex() { --temp_index_; }
+  void DeallocateTempIndex(intptr_t n) {
+    ASSERT(temp_index_ >= n);
+    temp_index_ -= n;
+  }
 
   virtual void CompiletimeStringInterpolation(const Function& interpol_func,
                                               const Array& literals);
 
   Definition* BuildObjectAllocation(ConstructorCallNode* node);
   void BuildConstructorCall(ConstructorCallNode* node, Value* alloc_value);
 
   void BuildStoreContext(const LocalVariable& variable);
   void BuildLoadContext(const LocalVariable& variable);
 
@@ skipping 50 matching lines @@
   // Helper to set the output state to return a Value.
   virtual void ReturnValue(Value* value) {
     ASSERT(value->IsUse() || value->IsTemp());
     value_ = value;
   }
 
   // Specify a computation as the final result.  Adds a Bind instruction to
   // the graph and returns its temporary value (i.e., set the output
   // parameters).
   virtual void ReturnComputation(Computation* computation) {
-    BindInstr* defn = new BindInstr(temp_index(), computation);
+    BindInstr* defn = new BindInstr(computation);
     AddInstruction(defn);
-    AllocateTempIndex();
-    value_ = new UseVal(defn);
+    ReturnValue(new UseVal(defn));
   }
 
   virtual void CompiletimeStringInterpolation(const Function& interpol_func,
                                               const Array& literals);
 
   virtual void BuildInstanceOf(ComparisonNode* node);
 };
 
 
 // Translate an AstNode to a control-flow graph fragment for both its
@@ skipping 33 matching lines @@
     return false_successor_address_;
   }
 
   intptr_t condition_token_index() const { return condition_token_index_; }
 
  private:
   // Construct and concatenate a Branch instruction to this graph fragment.
   // Closes the fragment and sets the output parameters.
   virtual void ReturnValue(Value* value);
 
-  // Specify a computation as the final result.  Adds a Bind instruction to
-  // the graph and branches on its value.
-  virtual void ReturnComputation(Computation* computation) {
-    BindInstr* defn = new BindInstr(temp_index(), computation);
-    AddInstruction(defn);
-    ReturnValue(new UseVal(defn));
-  }
-
   // Output parameters.
   TargetEntryInstr** true_successor_address_;
   TargetEntryInstr** false_successor_address_;
 
   intptr_t condition_token_index_;
 };
 
 }  // namespace dart
 
 #endif  // VM_FLOW_GRAPH_BUILDER_H_