VectorICs: recreate feedback vector if scoping changes on recompile.

BUG=476488
LOG=N
R=jarin@chromium.org

Review URL: https://codereview.chromium.org/1080253003

Cr-Commit-Position: refs/heads/master@{#27817}

src/compiler.cc

@@ -251,7 +251,8 @@ bool CompilationInfo::ShouldSelfOptimize() {
 
 
 void CompilationInfo::EnsureFeedbackVector() {
-  if (feedback_vector_.is_null()) {
+  if (feedback_vector_.is_null() ||
+      feedback_vector_->SpecDiffersFrom(function()->feedback_vector_spec())) {
     feedback_vector_ = isolate()->factory()->NewTypeFeedbackVector(
         function()->feedback_vector_spec());
   }

src/type-feedback-vector.cc

@@ -137,6 +137,22 @@ Handle<TypeFeedbackVector> TypeFeedbackVector::Copy(
 }
 
 
+bool TypeFeedbackVector::SpecDiffersFrom(
+    const ZoneFeedbackVectorSpec* other_spec) const {
+  if (other_spec->slots() != Slots() || other_spec->ic_slots() != ICSlots()) {
+    return true;
+  }
+
+  int ic_slots = ICSlots();
+  for (int i = 0; i < ic_slots; i++) {
+    if (GetKind(FeedbackVectorICSlot(i)) != other_spec->GetKind(i)) {
+      return true;
+    }
+  }
+  return false;
+}
+
+
 // This logic is copied from
 // StaticMarkingVisitor<StaticVisitor>::VisitCodeTarget.
 static bool ClearLogic(Heap* heap) {

src/type-feedback-vector.h

@@ -134,6 +134,8 @@ class TypeFeedbackVector : public FixedArray {
 
   inline int ic_metadata_length() const;
 
+  bool SpecDiffersFrom(const ZoneFeedbackVectorSpec* other_spec) const;
+
   int Slots() const {
     if (length() == 0) return 0;
     return Max(

test/mjsunit/regress/regress-476488.js

+// Copyright 2015 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.
+
+// Flags: --always-opt --expose-gc
+
+function __f_0(message, a) {
+  eval(), message;
+  (function blue() {
+    'use strict';
+    eval(), eval(), message;
+    gc();
+  })();
+}
+__f_0();