Always wrap AllocationSiteContext::current() in a new handle in Crankshaft.

R=mvstanton@chromium.org
BUG=

Review URL: https://codereview.chromium.org/1086863003

Cr-Commit-Position: refs/heads/master@{#27935}

src/allocation-site-scopes.h

@@ -75,7 +75,6 @@ class AllocationSiteUsageContext : public AllocationSiteContext {
       // Advance current site
       Object* nested_site = current()->nested_site();
       // Something is wrong if we advance to the end of the list here.
-      DCHECK(nested_site->IsAllocationSite());
       update_current_site(AllocationSite::cast(nested_site));
     }
     return Handle<AllocationSite>(*current(), isolate());

src/hydrogen.cc

@@ -5590,10 +5590,10 @@ void HOptimizedGraphBuilder::VisitObjectLiteral(ObjectLiteral* expr) {
 
   if (!boilerplate.is_null() &&
       IsFastLiteral(boilerplate, kMaxFastLiteralDepth, &max_properties)) {
-    AllocationSiteUsageContext usage_context(isolate(), site, false);
-    usage_context.EnterNewScope();
-    literal = BuildFastLiteral(boilerplate, &usage_context);
-    usage_context.ExitScope(site, boilerplate);
+    AllocationSiteUsageContext site_context(isolate(), site, false);
+    site_context.EnterNewScope();
+    literal = BuildFastLiteral(boilerplate, &site_context);
+    site_context.ExitScope(site, boilerplate);
   } else {
     NoObservableSideEffectsScope no_effects(this);
     Handle<FixedArray> closure_literals(closure->literals(), isolate());
@@ -5754,10 +5754,10 @@ void HOptimizedGraphBuilder::VisitArrayLiteral(ArrayLiteral* expr) {
   if (IsFastLiteral(boilerplate_object,
                     kMaxFastLiteralDepth,
                     &max_properties)) {
-    AllocationSiteUsageContext usage_context(isolate(), site, false);
-    usage_context.EnterNewScope();
-    literal = BuildFastLiteral(boilerplate_object, &usage_context);
-    usage_context.ExitScope(site, boilerplate_object);
+    AllocationSiteUsageContext site_context(isolate(), site, false);
+    site_context.EnterNewScope();
+    literal = BuildFastLiteral(boilerplate_object, &site_context);
+    site_context.ExitScope(site, boilerplate_object);
   } else {
     NoObservableSideEffectsScope no_effects(this);
     // Boilerplate already exists and constant elements are never accessed,
@@ -11081,16 +11081,16 @@ HInstruction* HOptimizedGraphBuilder::BuildFastLiteral(
       boilerplate_object->map()->instance_size());
 
   PretenureFlag pretenure_flag = NOT_TENURED;
-  Handle<AllocationSite> site(site_context->current());
+  Handle<AllocationSite> current_site(*site_context->current(), isolate());
   if (FLAG_allocation_site_pretenuring) {
-    pretenure_flag = site_context->current()->GetPretenureMode();
-    AllocationSite::RegisterForDeoptOnTenureChange(site, top_info());
+    pretenure_flag = current_site->GetPretenureMode();
+    AllocationSite::RegisterForDeoptOnTenureChange(current_site, top_info());
   }
 
-  AllocationSite::RegisterForDeoptOnTransitionChange(site, top_info());
+  AllocationSite::RegisterForDeoptOnTransitionChange(current_site, top_info());
 
-  HInstruction* object = Add<HAllocate>(object_size_constant, type,
-      pretenure_flag, instance_type, site_context->current());
+  HInstruction* object = Add<HAllocate>(
+      object_size_constant, type, pretenure_flag, instance_type, current_site);
 
   // If allocation folding reaches Page::kMaxRegularHeapObjectSize the
   // elements array may not get folded into the object. Hence, we set the
@@ -11125,9 +11125,9 @@ HInstruction* HOptimizedGraphBuilder::BuildFastLiteral(
     HValue* object_elements_size = Add<HConstant>(elements_size);
     InstanceType instance_type = boilerplate_object->HasFastDoubleElements()
         ? FIXED_DOUBLE_ARRAY_TYPE : FIXED_ARRAY_TYPE;
-    object_elements = Add<HAllocate>(
-        object_elements_size, HType::HeapObject(),
-        pretenure_flag, instance_type, site_context->current());
+    object_elements =
+        Add<HAllocate>(object_elements_size, HType::HeapObject(),
+                       pretenure_flag, instance_type, current_site);
   }
   BuildInitElementsInObjectHeader(boilerplate_object, object, object_elements);