Merged FeedbackSlotInterface into AstNode, removing the need for a 2nd vtable.

This tiny change shaves off 112MB from the peak memory usage in the
bug mentioned below, more to come...

BUG=417697
LOG=y
R=mvstanton@chromium.org

Review URL: https://codereview.chromium.org/611393004

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@24390 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/ast.h

@@ -11,7 +11,6 @@
 #include "src/ast-value-factory.h"
 #include "src/bailout-reason.h"
 #include "src/factory.h"
-#include "src/feedback-slots.h"
 #include "src/interface.h"
 #include "src/isolate.h"
 #include "src/jsregexp.h"
@@ -233,6 +232,17 @@ class AstNode: public ZoneObject {
   virtual IterationStatement* AsIterationStatement() { return NULL; }
   virtual MaterializedLiteral* AsMaterializedLiteral() { return NULL; }
 
+  // The interface for feedback slots, with default no-op implementations for
+  // node types which don't actually have this. Note that this is conceptually
+  // not really nice, but multiple inheritance would introduce yet another
+  // vtable entry per node, something we don't want for space reasons.
+  static const int kInvalidFeedbackSlot = -1;
+  virtual int ComputeFeedbackSlotCount() {
+    UNREACHABLE();
+    return 0;
+  }
+  virtual void SetFirstFeedbackSlot(int slot) { UNREACHABLE(); }
+
  protected:
   // Some nodes re-use bailout IDs for type feedback.
   static TypeFeedbackId reuse(BailoutId id) {
@@ -914,8 +924,7 @@ class ForEachStatement : public IterationStatement {
 };
 
 
-class ForInStatement FINAL : public ForEachStatement,
-    public FeedbackSlotInterface {
+class ForInStatement FINAL : public ForEachStatement {
  public:
   DECLARE_NODE_TYPE(ForInStatement)
 
@@ -1628,7 +1637,7 @@ class ArrayLiteral FINAL : public MaterializedLiteral {
 };
 
 
-class VariableProxy FINAL : public Expression, public FeedbackSlotInterface {
+class VariableProxy FINAL : public Expression {
  public:
   DECLARE_NODE_TYPE(VariableProxy)
 
@@ -1672,7 +1681,7 @@ class VariableProxy FINAL : public Expression, public FeedbackSlotInterface {
 };
 
 
-class Property FINAL : public Expression, public FeedbackSlotInterface {
+class Property FINAL : public Expression {
  public:
   DECLARE_NODE_TYPE(Property)
 
@@ -1741,7 +1750,7 @@ class Property FINAL : public Expression, public FeedbackSlotInterface {
 };
 
 
-class Call FINAL : public Expression, public FeedbackSlotInterface {
+class Call FINAL : public Expression {
  public:
   DECLARE_NODE_TYPE(Call)
 
@@ -1844,7 +1853,7 @@ class Call FINAL : public Expression, public FeedbackSlotInterface {
 };
 
 
-class CallNew FINAL : public Expression, public FeedbackSlotInterface {
+class CallNew FINAL : public Expression {
  public:
   DECLARE_NODE_TYPE(CallNew)
 
@@ -1907,7 +1916,7 @@ class CallNew FINAL : public Expression, public FeedbackSlotInterface {
 // language construct. Instead it is used to call a C or JS function
 // with a set of arguments. This is used from the builtins that are
 // implemented in JavaScript (see "v8natives.js").
-class CallRuntime FINAL : public Expression, public FeedbackSlotInterface {
+class CallRuntime FINAL : public Expression {
  public:
   DECLARE_NODE_TYPE(CallRuntime)
 
@@ -2223,7 +2232,7 @@ class Assignment FINAL : public Expression {
 };
 
 
-class Yield FINAL : public Expression, public FeedbackSlotInterface {
+class Yield FINAL : public Expression {
  public:
   DECLARE_NODE_TYPE(Yield)
 
@@ -3038,7 +3047,7 @@ class AstConstructionVisitor BASE_EMBEDDED {
     dont_turbofan_reason_ = reason;
   }
 
-  void add_slot_node(FeedbackSlotInterface* slot_node) {
+  void add_slot_node(AstNode* slot_node) {
     int count = slot_node->ComputeFeedbackSlotCount();
     if (count > 0) {
       slot_node->SetFirstFeedbackSlot(properties_.feedback_slots());

src/feedback-slots.h

-// Copyright 2014 the V8 project authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#ifndef V8_FEEDBACK_SLOTS_H_
-#define V8_FEEDBACK_SLOTS_H_
-
-#include "src/v8.h"
-
-#include "src/isolate.h"
-
-namespace v8 {
-namespace internal {
-
-class FeedbackSlotInterface {
- public:
-  static const int kInvalidFeedbackSlot = -1;
-
-  virtual ~FeedbackSlotInterface() {}
-
-  virtual int ComputeFeedbackSlotCount() = 0;
-  virtual void SetFirstFeedbackSlot(int slot) = 0;
-};
-
-} }  // namespace v8::internal
-
-#endif  // V8_FEEDBACK_SLOTS_H_

src/hydrogen-instructions.h

@@ -15,7 +15,6 @@
 #include "src/conversions.h"
 #include "src/data-flow.h"
 #include "src/deoptimizer.h"
-#include "src/feedback-slots.h"
 #include "src/hydrogen-types.h"
 #include "src/small-pointer-list.h"
 #include "src/unique.h"
@@ -5475,8 +5474,7 @@ class HLoadGlobalGeneric FINAL : public HTemplateInstruction<2> {
   Handle<String> name() const { return name_; }
   bool for_typeof() const { return for_typeof_; }
   int slot() const {
-    DCHECK(FLAG_vector_ics &&
-           slot_ != FeedbackSlotInterface::kInvalidFeedbackSlot);
+    DCHECK(FLAG_vector_ics && slot_ != AstNode::kInvalidFeedbackSlot);
     return slot_;
   }
   Handle<FixedArray> feedback_vector() const { return feedback_vector_; }
@@ -5497,8 +5495,9 @@ class HLoadGlobalGeneric FINAL : public HTemplateInstruction<2> {
  private:
   HLoadGlobalGeneric(HValue* context, HValue* global_object,
                      Handle<String> name, bool for_typeof)
-      : name_(name), for_typeof_(for_typeof),
-        slot_(FeedbackSlotInterface::kInvalidFeedbackSlot) {
+      : name_(name),
+        for_typeof_(for_typeof),
+        slot_(AstNode::kInvalidFeedbackSlot) {
     SetOperandAt(0, context);
     SetOperandAt(1, global_object);
     set_representation(Representation::Tagged());
@@ -6478,8 +6477,7 @@ class HLoadNamedGeneric FINAL : public HTemplateInstruction<2> {
   Handle<Object> name() const { return name_; }
 
   int slot() const {
-    DCHECK(FLAG_vector_ics &&
-           slot_ != FeedbackSlotInterface::kInvalidFeedbackSlot);
+    DCHECK(FLAG_vector_ics && slot_ != AstNode::kInvalidFeedbackSlot);
     return slot_;
   }
   Handle<FixedArray> feedback_vector() const { return feedback_vector_; }
@@ -6499,8 +6497,7 @@ class HLoadNamedGeneric FINAL : public HTemplateInstruction<2> {
 
  private:
   HLoadNamedGeneric(HValue* context, HValue* object, Handle<Object> name)
-      : name_(name),
-        slot_(FeedbackSlotInterface::kInvalidFeedbackSlot) {
+      : name_(name), slot_(AstNode::kInvalidFeedbackSlot) {
     SetOperandAt(0, context);
     SetOperandAt(1, object);
     set_representation(Representation::Tagged());
@@ -6756,8 +6753,7 @@ class HLoadKeyedGeneric FINAL : public HTemplateInstruction<3> {
   HValue* key() const { return OperandAt(1); }
   HValue* context() const { return OperandAt(2); }
   int slot() const {
-    DCHECK(FLAG_vector_ics &&
-           slot_ != FeedbackSlotInterface::kInvalidFeedbackSlot);
+    DCHECK(FLAG_vector_ics && slot_ != AstNode::kInvalidFeedbackSlot);
     return slot_;
   }
   Handle<FixedArray> feedback_vector() const { return feedback_vector_; }
@@ -6780,7 +6776,7 @@ class HLoadKeyedGeneric FINAL : public HTemplateInstruction<3> {
 
  private:
   HLoadKeyedGeneric(HValue* context, HValue* obj, HValue* key)
-      : slot_(FeedbackSlotInterface::kInvalidFeedbackSlot) {
+      : slot_(AstNode::kInvalidFeedbackSlot) {
     set_representation(Representation::Tagged());
     SetOperandAt(0, obj);
     SetOperandAt(1, key);