[Interpreter] Reduce temporary register usage in generated bytecode.

src/interpreter/bytecode-generator.h

Index: src/interpreter/bytecode-generator.h
diff --git a/src/interpreter/bytecode-generator.h b/src/interpreter/bytecode-generator.h
index e79ff787e9246ba278bddfa09a3e48daf21a7fc2..a9ee53aee7e61b85a6875668b7a93e24fbc9b262 100644
--- a/src/interpreter/bytecode-generator.h
+++ b/src/interpreter/bytecode-generator.h
@@ -31,14 +31,17 @@ class BytecodeGenerator : public AstVisitor {
   class ContextScope;
   class ControlScope;
   class ControlScopeForIteration;
+  class ExpressionResultScope;
+  class EffectResultScope;
+  class AccumulatorResultScope;
+  class RegisterResultScope;
 
   void MakeBytecodeBody();
   Register NextContextRegister() const;
 
   DEFINE_AST_VISITOR_SUBCLASS_MEMBERS();
 
-  Register VisitArguments(ZoneList<Expression*>* arguments,
-                          TemporaryRegisterScope* caller_scope);
+  Register VisitArguments(ZoneList<Expression*>* arguments);
   void VisitArithmeticExpression(BinaryOperation* binop);
   void VisitCommaExpression(BinaryOperation* binop);
   void VisitLogicalOrExpression(BinaryOperation* binop);
@@ -61,6 +64,18 @@ class BytecodeGenerator : public AstVisitor {
   void VisitTypeOf(UnaryOperation* expr);
   void VisitNot(UnaryOperation* expr);
 
+  // Visitors for obtaining expression result in the accumulator, in a
+  // register, or just getting the effect.
+  void VisitForAccumulatorValue(Expression* expression);
+  MUST_USE_RESULT Register VisitForRegisterValue(Expression* expression);
+  void VisitForEffect(Expression* node);
+
+  // Binary expression state machine and load-store tracking.
+  void PrepareForBinaryExpression();
+  void RecordStoreToRegister(Register reg);
+  Register LoadFromAliasedRegister(Register reg);

[rmcilroy, 2015/10/20 16:39:20]

nit - move these into a seperate block from PrepareForBinaryExpression /
CompleteBinaryExpression and update comments

[oth, 2015/10/20 20:58:42]

Done.

+  void CompleteBinaryExpression();
+
   inline BytecodeArrayBuilder* builder() { return &builder_; }
 
   inline Isolate* isolate() const { return isolate_; }
@@ -79,6 +94,10 @@ class BytecodeGenerator : public AstVisitor {
   inline void set_execution_context(ContextScope* context) {
     execution_context_ = context;
   }
+  inline void set_result_scope(ExpressionResultScope* result_scope) {
+    result_scope_ = result_scope;
+  }
+  ExpressionResultScope* result_scope() const { return result_scope_; }

[rmcilroy, 2015/10/20 16:39:20]

optional nit - should we call this execution_result() to tie in with the scopes
above?

[oth, 2015/10/20 20:58:42]

Done.

 
   ZoneVector<Handle<Object>>* globals() { return &globals_; }
   inline LanguageMode language_mode() const;
@@ -93,6 +112,10 @@ class BytecodeGenerator : public AstVisitor {
   ZoneVector<Handle<Object>> globals_;
   ControlScope* execution_control_;
   ContextScope* execution_context_;
+  ExpressionResultScope* result_scope_;
+
+  int binary_expression_depth_;
+  ZoneSet<int> binary_expression_hazard_set_;
 };
 
 }  // namespace interpreter