Remove variable rewrites and the unneccesary Slot class.

src/full-codegen.h

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 270 matching lines @@
   // Type of a member function that generates inline code for a native function.
   typedef void (FullCodeGenerator::*InlineFunctionGenerator)
       (ZoneList<Expression*>*);
 
   static const InlineFunctionGenerator kInlineFunctionGenerators[];
 
   // A platform-specific utility to overwrite the accumulator register
   // with a GC-safe value.
   void ClearAccumulator();
 
-  // Compute the frame pointer relative offset for a given local or
-  // parameter slot.
-  int SlotOffset(Slot* slot);
-
   // Determine whether or not to inline the smi case for the given
   // operation.
   bool ShouldInlineSmiCase(Token::Value op);
 
   // Helper function to convert a pure value into a test context.  The value
   // is expected on the stack or the accumulator, depending on the platform.
   // See the platform-specific implementation for details.
   void DoTest(Expression* condition,
               Label* if_true,
               Label* if_false,
               Label* fall_through);
   void DoTest(const TestContext* context);
 
   // Helper function to split control flow and avoid a branch to the
   // fall-through label if it is set up.
 #ifdef V8_TARGET_ARCH_MIPS
   void Split(Condition cc,
              Register lhs,
              const Operand&  rhs,
              Label* if_true,
              Label* if_false,
              Label* fall_through);
 #else  // All non-mips arch.
   void Split(Condition cc,
              Label* if_true,
              Label* if_false,
              Label* fall_through);
 #endif  // V8_TARGET_ARCH_MIPS
 
-  void Move(Slot* dst, Register source, Register scratch1, Register scratch2);
-  void Move(Register dst, Slot* source);
+  // Load the value of a known (PARAMETER, LOCAL, or CONTEXT) variable into
+  // a register.  Emits a context chain walk if if necessary (so does
+  // SetVar) so avoid calling both on the same variable.
+  void GetVar(Register destination, Variable* var);
 
-  // Return an operand used to read/write to a known (ie, non-LOOKUP) slot.
-  // May emit code to traverse the context chain, destroying the scratch
-  // register.
-  MemOperand EmitSlotSearch(Slot* slot, Register scratch);
+  // Assign to a known (PARAMETER, LOCAL, or CONTEXT) variable.  If it's in
+  // the context, the write barrier will be emitted and source, scratch0,
+  // scratch1 will be clobbered.  Emits a context chain walk if if necessary
+  // (so does GetVar) so avoid calling both on the same variable.
+  void SetVar(Variable* var,
+              Register source,
+              Register scratch0,
+              Register scratch1);
+
+  // An operand used to read/write a stack-allocated (PARAMETER or LOCAL)
+  // variable.  Writing does not need the write barrier.
+  MemOperand StackOperand(Variable* var);
+
+  // An operand used to read/write a known (PARAMETER, LOCAL, or CONTEXT)
+  // variable.  May emit code to traverse the context chain, loading the
+  // found context into the scratch register.  Writing to this operand will
+  // need the write barrier if location is CONTEXT.
+  MemOperand VarOperand(Variable* var, Register scratch);
 
   // Forward the bailout responsibility for the given expression to
   // the next child visited (which must be in a test context).
   void ForwardBailoutToChild(Expression* expr);
 
   void VisitForEffect(Expression* expr) {
     EffectContext context(this);
     VisitInCurrentContext(expr);
   }
 
@@ skipping 57 matching lines @@
   // should_normalize, the true and false labels are ignored.
   void PrepareForBailoutBeforeSplit(State state,
                                     bool should_normalize,
                                     Label* if_true,
                                     Label* if_false);
 
   // Platform-specific code for a variable, constant, or function
   // declaration.  Functions have an initial value.
   void EmitDeclaration(VariableProxy* proxy,
                        Variable::Mode mode,
-                       FunctionLiteral* function);
+                       FunctionLiteral* function,
+                       int* global_count);
 
   // Platform-specific code for checking the stack limit at the back edge of
   // a loop.
   void EmitStackCheck(IterationStatement* stmt);
   // Record the OSR AST id corresponding to a stack check in the code.
   void RecordStackCheck(int osr_ast_id);
   // Emit a table of stack check ids and pcs into the code stream.  Return
   // the offset of the start of the table.
   unsigned EmitStackCheckTable();
 
@@ skipping 10 matching lines @@
 
   void EmitInlineRuntimeCall(CallRuntime* expr);
 
 #define EMIT_INLINE_RUNTIME_CALL(name, x, y) \
   void Emit##name(ZoneList<Expression*>* arguments);
   INLINE_FUNCTION_LIST(EMIT_INLINE_RUNTIME_CALL)
   INLINE_RUNTIME_FUNCTION_LIST(EMIT_INLINE_RUNTIME_CALL)
 #undef EMIT_INLINE_RUNTIME_CALL
 
   // Platform-specific code for loading variables.
-  void EmitLoadGlobalSlotCheckExtensions(Slot* slot,
-                                         TypeofState typeof_state,
-                                         Label* slow);
-  MemOperand ContextSlotOperandCheckExtensions(Slot* slot, Label* slow);
-  void EmitDynamicLoadFromSlotFastCase(Slot* slot,
-                                       TypeofState typeof_state,
-                                       Label* slow,
-                                       Label* done);
+  void EmitLoadGlobalCheckExtensions(Variable* var,
+                                     TypeofState typeof_state,
+                                     Label* slow);
+  MemOperand ContextSlotOperandCheckExtensions(Variable* var, Label* slow);
+  void EmitDynamicLookupFastCase(Variable* var,
+                                 TypeofState typeof_state,
+                                 Label* slow,
+                                 Label* done);
   void EmitVariableLoad(VariableProxy* proxy);
 
   enum ResolveEvalFlag {
     SKIP_CONTEXT_LOOKUP,
     PERFORM_CONTEXT_LOOKUP
   };
 
   // Expects the arguments and the function already pushed.
   void EmitResolvePossiblyDirectEval(ResolveEvalFlag flag, int arg_count);
 
@@ skipping 156 matching lines @@
         codegen()->verify_stack_height();
       }
     }
 
     Isolate* isolate() const { return codegen_->isolate(); }
 
     // Convert constant control flow (true or false) to the result expected for
     // this expression context.
     virtual void Plug(bool flag) const = 0;
 
-    // Emit code to convert a pure value (in a register, slot, as a literal,
-    // or on top of the stack) into the result expected according to this
-    // expression context.
+    // Emit code to convert a pure value (in a register, known variable
+    // location, as a literal, or on top of the stack) into the result
+    // expected according to this expression context.
     virtual void Plug(Register reg) const = 0;
-    virtual void Plug(Slot* slot) const = 0;
+    virtual void Plug(Variable* var) const = 0;
     virtual void Plug(Handle<Object> lit) const = 0;
     virtual void Plug(Heap::RootListIndex index) const = 0;
     virtual void PlugTOS() const = 0;
 
     // Emit code to convert pure control flow to a pair of unbound labels into
     // the result expected according to this expression context.  The
     // implementation will bind both labels unless it's a TestContext, which
     // won't bind them at this point.
     virtual void Plug(Label* materialize_true,
                       Label* materialize_false) const = 0;
@@ skipping 37 matching lines @@
   class AccumulatorValueContext : public ExpressionContext {
    public:
     explicit AccumulatorValueContext(FullCodeGenerator* codegen)
         : ExpressionContext(codegen) {
       expected_stack_height_ = codegen->stack_height();
     }
 
     virtual void Plug(bool flag) const;
     virtual void Plug(Register reg) const;
     virtual void Plug(Label* materialize_true, Label* materialize_false) const;
-    virtual void Plug(Slot* slot) const;
+    virtual void Plug(Variable* var) const;
     virtual void Plug(Handle<Object> lit) const;
     virtual void Plug(Heap::RootListIndex) const;
     virtual void PlugTOS() const;
     virtual void DropAndPlug(int count, Register reg) const;
     virtual void PrepareTest(Label* materialize_true,
                              Label* materialize_false,
                              Label** if_true,
                              Label** if_false,
                              Label** fall_through) const;
     virtual bool IsAccumulatorValue() const { return true; }
   };
 
   class StackValueContext : public ExpressionContext {
    public:
     explicit StackValueContext(FullCodeGenerator* codegen)
         : ExpressionContext(codegen) {
       expected_stack_height_ = codegen->stack_height() + 1;
     }
 
     virtual void Plug(bool flag) const;
     virtual void Plug(Register reg) const;
     virtual void Plug(Label* materialize_true, Label* materialize_false) const;
-    virtual void Plug(Slot* slot) const;
+    virtual void Plug(Variable* var) const;
     virtual void Plug(Handle<Object> lit) const;
     virtual void Plug(Heap::RootListIndex) const;
     virtual void PlugTOS() const;
     virtual void DropAndPlug(int count, Register reg) const;
     virtual void PrepareTest(Label* materialize_true,
                              Label* materialize_false,
                              Label** if_true,
                              Label** if_false,
                              Label** fall_through) const;
     virtual bool IsStackValue() const { return true; }
@@ skipping 20 matching lines @@
     }
 
     Expression* condition() const { return condition_; }
     Label* true_label() const { return true_label_; }
     Label* false_label() const { return false_label_; }
     Label* fall_through() const { return fall_through_; }
 
     virtual void Plug(bool flag) const;
     virtual void Plug(Register reg) const;
     virtual void Plug(Label* materialize_true, Label* materialize_false) const;
-    virtual void Plug(Slot* slot) const;
+    virtual void Plug(Variable* var) const;
     virtual void Plug(Handle<Object> lit) const;
     virtual void Plug(Heap::RootListIndex) const;
     virtual void PlugTOS() const;
     virtual void DropAndPlug(int count, Register reg) const;
     virtual void PrepareTest(Label* materialize_true,
                              Label* materialize_false,
                              Label** if_true,
                              Label** if_false,
                              Label** fall_through) const;
     virtual bool IsTest() const { return true; }
 
    private:
     Expression* condition_;
     Label* true_label_;
     Label* false_label_;
     Label* fall_through_;
   };
 
   class EffectContext : public ExpressionContext {
    public:
     explicit EffectContext(FullCodeGenerator* codegen)
         : ExpressionContext(codegen) {
       expected_stack_height_ = codegen->stack_height();
     }
 
 
     virtual void Plug(bool flag) const;
     virtual void Plug(Register reg) const;
     virtual void Plug(Label* materialize_true, Label* materialize_false) const;
-    virtual void Plug(Slot* slot) const;
+    virtual void Plug(Variable* var) const;
     virtual void Plug(Handle<Object> lit) const;
     virtual void Plug(Heap::RootListIndex) const;
     virtual void PlugTOS() const;
     virtual void DropAndPlug(int count, Register reg) const;
     virtual void PrepareTest(Label* materialize_true,
                              Label* materialize_false,
                              Label** if_true,
                              Label** if_false,
                              Label** fall_through) const;
     virtual bool IsEffect() const { return true; }
@@ skipping 14 matching lines @@
 
   friend class NestedStatement;
 
   DISALLOW_COPY_AND_ASSIGN(FullCodeGenerator);
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_FULL_CODEGEN_H_