Allocation space decisions are precisely made in hydrogen.

src/hydrogen.cc

 // Copyright 2013 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 1306 matching lines @@
   HConstant* elements_size_value = Add<HConstant>(elements_size);
   HValue* mul = AddInstruction(
                     HMul::New(zone, context, capacity, elements_size_value));
   mul->ClearFlag(HValue::kCanOverflow);
 
   HConstant* header_size = Add<HConstant>(FixedArray::kHeaderSize);
   HValue* total_size = AddInstruction(
                            HAdd::New(zone, context, mul, header_size));
   total_size->ClearFlag(HValue::kCanOverflow);
 
-  HAllocate::Flags flags = HAllocate::DefaultFlags(kind);
-  if (isolate()->heap()->ShouldGloballyPretenure()) {
-    // TODO(hpayer): When pretenuring can be internalized, flags can become
-    // private to HAllocate.
-    if (IsFastDoubleElementsKind(kind)) {
-      flags = static_cast<HAllocate::Flags>(
-          flags | HAllocate::CAN_ALLOCATE_IN_OLD_DATA_SPACE);
-    } else {
-      flags = static_cast<HAllocate::Flags>(
-          flags | HAllocate::CAN_ALLOCATE_IN_OLD_POINTER_SPACE);
-    }
-  }
-
-  return Add<HAllocate>(context, total_size, HType::JSArray(), flags);
+  return Add<HAllocate>(context, total_size, HType::JSArray(),
+      isolate()->heap()->ShouldGloballyPretenure(), kind);
 }
 
 
 void HGraphBuilder::BuildInitializeElementsHeader(HValue* elements,
                                                   ElementsKind kind,
                                                   HValue* capacity) {
   Factory* factory = isolate()->factory();
   Handle<Map> map = IsFastDoubleElementsKind(kind)
       ? factory->fixed_double_array_map()
       : factory->fixed_array_map();
@@ skipping 310 matching lines @@
   if (mode == TRACK_ALLOCATION_SITE) {
     size += AllocationMemento::kSize;
   }
   int elems_offset = size;
   if (length > 0) {
     size += IsFastDoubleElementsKind(kind)
         ? FixedDoubleArray::SizeFor(length)
         : FixedArray::SizeFor(length);
   }
 
-  HAllocate::Flags allocate_flags = HAllocate::DefaultFlags(kind);
   // Allocate both the JS array and the elements array in one big
   // allocation. This avoids multiple limit checks.
   HValue* size_in_bytes = Add<HConstant>(size);
   HInstruction* object = Add<HAllocate>(context,
                                         size_in_bytes,
                                         HType::JSObject(),
-                                        allocate_flags);
+                                        false,
+                                        kind);
 
   // Copy the JS array part.
   for (int i = 0; i < JSArray::kSize; i += kPointerSize) {
     if ((i != JSArray::kElementsOffset) || (length == 0)) {
       HObjectAccess access = HObjectAccess::ForJSArrayOffset(i);
       AddStore(object, access, AddLoad(boilerplate, access));
     }
   }
 
   // Create an allocation site info if requested.
@@ skipping 261 matching lines @@
 
   // These HForceRepresentations are because we store these as fields in the
   // objects we construct, and an int32-to-smi HChange could deopt. Accept
   // the deopt possibility now, before allocation occurs.
   capacity = builder()->Add<HForceRepresentation>(capacity,
                                                   Representation::Smi());
   length_field = builder()->Add<HForceRepresentation>(length_field,
                                                       Representation::Smi());
 
   // Allocate (dealing with failure appropriately)
-  HAllocate::Flags flags = HAllocate::DefaultFlags(kind_);
   HAllocate* new_object = builder()->Add<HAllocate>(context, size_in_bytes,
-                                                    HType::JSArray(), flags);
+      HType::JSArray(), false, kind_);
 
   // Fill in the fields: map, properties, length
   HValue* map;
   if (allocation_site_payload_ == NULL) {
     map = EmitInternalMapCode();
   } else {
     map = EmitMapCode(context);
   }
   elements_location_ = builder()->BuildJSArrayHeader(new_object,
                                                      map,
@@ skipping 2624 matching lines @@
   HStoreNamedField *instr;
   if (FLAG_track_double_fields && field_access.representation().IsDouble()) {
     HObjectAccess heap_number_access =
         field_access.WithRepresentation(Representation::Tagged());
     if (transition_to_field) {
       // The store requires a mutable HeapNumber to be allocated.
       NoObservableSideEffectsScope no_side_effects(this);
       HInstruction* heap_number_size = Add<HConstant>(HeapNumber::kSize);
       HInstruction* heap_number = Add<HAllocate>(
           environment()->LookupContext(), heap_number_size,
-          HType::HeapNumber(), HAllocate::CAN_ALLOCATE_IN_NEW_SPACE);
+          HType::HeapNumber(), false);
       AddStoreMapConstant(heap_number, isolate()->factory()->heap_number_map());
       AddStore(heap_number, HObjectAccess::ForHeapNumberValue(), value);
       instr = new(zone()) HStoreNamedField(
           object, heap_number_access, heap_number);
     } else {
       // Already holds a HeapNumber; load the box and write its value field.
       HInstruction* heap_number = AddLoad(object, heap_number_access);
       heap_number->set_type(HType::HeapNumber());
       instr = new(zone()) HStoreNamedField(heap_number,
           HObjectAccess::ForHeapNumberValue(), value);
@@ skipping 2615 matching lines @@
     }
 
     // Calculate instance size from initial map of constructor.
     ASSERT(constructor->has_initial_map());
     Handle<Map> initial_map(constructor->initial_map());
     int instance_size = initial_map->instance_size();
     ASSERT(initial_map->InitialPropertiesLength() == 0);
 
     // Allocate an instance of the implicit receiver object.
     HValue* size_in_bytes = Add<HConstant>(instance_size);
-    HAllocate::Flags flags = HAllocate::DefaultFlags();
-    if (FLAG_pretenuring_call_new &&
-        isolate()->heap()->ShouldGloballyPretenure()) {
-      flags = static_cast<HAllocate::Flags>(
-          flags | HAllocate::CAN_ALLOCATE_IN_OLD_POINTER_SPACE);
-    }
+    bool pretenure = FLAG_pretenuring_call_new &&
+        isolate()->heap()->ShouldGloballyPretenure();
     HAllocate* receiver =
-        Add<HAllocate>(context, size_in_bytes, HType::JSObject(), flags);
+        Add<HAllocate>(context, size_in_bytes, HType::JSObject(), pretenure);
     receiver->set_known_initial_map(initial_map);
 
     // Load the initial map from the constructor.
     HValue* constructor_value = Add<HConstant>(constructor);
     HValue* initial_map_value =
         AddLoad(constructor_value, HObjectAccess::ForJSObjectOffset(
             JSFunction::kPrototypeOrInitialMapOffset));
 
     // Initialize map and fields of the newly allocated object.
     { NoObservableSideEffectsScope no_effects(this);
@@ skipping 1061 matching lines @@
     AllocationSiteMode mode) {
   NoObservableSideEffectsScope no_effects(this);
 
   HInstruction* target = NULL;
   HInstruction* data_target = NULL;
 
   ElementsKind kind = boilerplate_object->map()->elements_kind();
 
   if (isolate()->heap()->ShouldGloballyPretenure()) {
     if (data_size != 0) {
-      HAllocate::Flags data_flags =
-          static_cast<HAllocate::Flags>(HAllocate::DefaultFlags(kind) |
-              HAllocate::CAN_ALLOCATE_IN_OLD_DATA_SPACE);
       HValue* size_in_bytes = Add<HConstant>(data_size);
       data_target = Add<HAllocate>(context, size_in_bytes, HType::JSObject(),
-          data_flags);
+          true, FAST_DOUBLE_ELEMENTS);
       Handle<Map> free_space_map = isolate()->factory()->free_space_map();
       AddStoreMapConstant(data_target, free_space_map);
       HObjectAccess access =
           HObjectAccess::ForJSObjectOffset(FreeSpace::kSizeOffset);
       AddStore(data_target, access, size_in_bytes);
     }
     if (pointer_size != 0) {
-      HAllocate::Flags pointer_flags =
-          static_cast<HAllocate::Flags>(HAllocate::DefaultFlags() |
-              HAllocate::CAN_ALLOCATE_IN_OLD_POINTER_SPACE);
       HValue* size_in_bytes = Add<HConstant>(pointer_size);
       target = Add<HAllocate>(context, size_in_bytes, HType::JSObject(),
-          pointer_flags);
+          true);
     }
   } else {
-    HAllocate::Flags flags = HAllocate::DefaultFlags(kind);
     HValue* size_in_bytes = Add<HConstant>(data_size + pointer_size);
-    target = Add<HAllocate>(context, size_in_bytes, HType::JSObject(), flags);
+    target = Add<HAllocate>(context, size_in_bytes, HType::JSObject(), false,
+        kind);
   }
 
   int offset = 0;
   int data_offset = 0;
   BuildEmitDeepCopy(boilerplate_object, original_boilerplate_object,
                     allocation_site, target, &offset, data_target,
                     &data_offset, mode);
   return target;
 }
 
@@ skipping 1575 matching lines @@
   if (ShouldProduceTraceOutput()) {
     isolate()->GetHTracer()->TraceHydrogen(name(), graph_);
   }
 
 #ifdef DEBUG
   graph_->Verify(false);  // No full verify.
 #endif
 }
 
 } }  // namespace v8::internal