[not for landing] Re-shuffle AllocationSite members

src/crankshaft/hydrogen.cc

 // Copyright 2013 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.
 
 #include "src/crankshaft/hydrogen.h"
 
 #include <sstream>
 
 #include "src/allocation-site-scopes.h"
 #include "src/ast/ast-numbering.h"
@@ skipping 3228 matching lines @@
   DCHECK(allocation_site != NULL);
   HInnerAllocatedObject* allocation_memento = Add<HInnerAllocatedObject>(
       previous_object, previous_object_size, HType::HeapObject());
   AddStoreMapConstant(
       allocation_memento, isolate()->factory()->allocation_memento_map());
   Add<HStoreNamedField>(
       allocation_memento,
       HObjectAccess::ForAllocationMementoSite(),
       allocation_site);
   if (FLAG_allocation_site_pretenuring) {
-    HValue* memento_create_count =
-        Add<HLoadNamedField>(allocation_site, nullptr,
-                             HObjectAccess::ForAllocationSiteOffset(
-                                 AllocationSite::kPretenureCreateCountOffset));
+    // The memento created counter is embedded in the first 26 bits of pretenure
+    // data. The value itself is bounded by new space size and cleared after
+    // every GC cycle. Overflow into the higher bits is thus not an issue.
+    HValue* memento_create_count = Add<HLoadNamedField>(
+        allocation_site, nullptr, HObjectAccess::ForAllocationSiteOffset(
+                                      AllocationSite::kPretenureDataOffset));
     memento_create_count = AddUncasted<HAdd>(
         memento_create_count, graph()->GetConstant1());
-    // This smi value is reset to zero after every gc, overflow isn't a problem
-    // since the counter is bounded by the new space size.
     memento_create_count->ClearFlag(HValue::kCanOverflow);
-    Add<HStoreNamedField>(
-        allocation_site, HObjectAccess::ForAllocationSiteOffset(
-            AllocationSite::kPretenureCreateCountOffset), memento_create_count);
+    Add<HStoreNamedField>(allocation_site,
+                          HObjectAccess::ForAllocationSiteOffset(
+                              AllocationSite::kPretenureDataOffset),
+                          memento_create_count);
   }
 }
 
 
 HInstruction* HGraphBuilder::BuildGetNativeContext() {
   return Add<HLoadNamedField>(
       context(), nullptr,
       HObjectAccess::ForContextSlot(Context::NATIVE_CONTEXT_INDEX));
 }
 
@@ skipping 10349 matching lines @@
     isolate()->GetHTracer()->TraceHydrogen(name(), graph_);
   }
 
 #ifdef DEBUG
   graph_->Verify(false);  // No full verify.
 #endif
 }
 
 }  // namespace internal
 }  // namespace v8