First implementation of allocation elimination in Hydrogen.

src/heap.cc

 // Copyright 2012 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 4457 matching lines @@
     // We might want to shrink the object later.
     ASSERT(obj->GetInternalFieldCount() == 0);
     filler = Heap::one_pointer_filler_map();
   } else {
     filler = Heap::undefined_value();
   }
   obj->InitializeBody(map, Heap::undefined_value(), filler);
 }
 
 
-MaybeObject* Heap::AllocateJSObjectFromMap(Map* map, PretenureFlag pretenure) {
+MaybeObject* Heap::AllocateJSObjectFromMap(
+    Map* map, PretenureFlag pretenure, bool allocate_properties) {
   // JSFunctions should be allocated using AllocateFunction to be
   // properly initialized.
   ASSERT(map->instance_type() != JS_FUNCTION_TYPE);
 
   // Both types of global objects should be allocated using
   // AllocateGlobalObject to be properly initialized.
   ASSERT(map->instance_type() != JS_GLOBAL_OBJECT_TYPE);
   ASSERT(map->instance_type() != JS_BUILTINS_OBJECT_TYPE);
 
   // Allocate the backing storage for the properties.
-  int prop_size = map->InitialPropertiesLength();
-  ASSERT(prop_size >= 0);
-  Object* properties;
-  { MaybeObject* maybe_properties = AllocateFixedArray(prop_size, pretenure);
-    if (!maybe_properties->ToObject(&properties)) return maybe_properties;
+  FixedArray* properties;
+  if (allocate_properties) {
+    int prop_size = map->InitialPropertiesLength();
+    ASSERT(prop_size >= 0);
+    { MaybeObject* maybe_properties = AllocateFixedArray(prop_size, pretenure);
+      if (!maybe_properties->To(&properties)) return maybe_properties;
+    }
+  } else {
+    properties = empty_fixed_array();
   }
 
   // Allocate the JSObject.
   AllocationSpace space =
       (pretenure == TENURED) ? OLD_POINTER_SPACE : NEW_SPACE;
   if (map->instance_size() > Page::kMaxNonCodeHeapObjectSize) space = LO_SPACE;
   Object* obj;
   MaybeObject* maybe_obj = Allocate(map, space);
   if (!maybe_obj->To(&obj)) return maybe_obj;
 
   // Initialize the JSObject.
-  InitializeJSObjectFromMap(JSObject::cast(obj),
-                            FixedArray::cast(properties),
-                            map);
+  InitializeJSObjectFromMap(JSObject::cast(obj), properties, map);
   ASSERT(JSObject::cast(obj)->HasFastElements() ||
          JSObject::cast(obj)->HasExternalArrayElements());
   return obj;
 }
 
 
-MaybeObject* Heap::AllocateJSObjectFromMapWithAllocationSite(Map* map,
-    Handle<AllocationSite> allocation_site) {
+MaybeObject* Heap::AllocateJSObjectFromMapWithAllocationSite(
+    Map* map, Handle<AllocationSite> allocation_site) {
   // JSFunctions should be allocated using AllocateFunction to be
   // properly initialized.
   ASSERT(map->instance_type() != JS_FUNCTION_TYPE);
 
   // Both types of global objects should be allocated using
   // AllocateGlobalObject to be properly initialized.
   ASSERT(map->instance_type() != JS_GLOBAL_OBJECT_TYPE);
   ASSERT(map->instance_type() != JS_BUILTINS_OBJECT_TYPE);
 
   // Allocate the backing storage for the properties.
   int prop_size = map->InitialPropertiesLength();
   ASSERT(prop_size >= 0);
-  Object* properties;
+  FixedArray* properties;
   { MaybeObject* maybe_properties = AllocateFixedArray(prop_size);
-    if (!maybe_properties->ToObject(&properties)) return maybe_properties;
+    if (!maybe_properties->To(&properties)) return maybe_properties;
   }
 
   // Allocate the JSObject.
   AllocationSpace space = NEW_SPACE;
   if (map->instance_size() > Page::kMaxNonCodeHeapObjectSize) space = LO_SPACE;
   Object* obj;
   MaybeObject* maybe_obj =
       AllocateWithAllocationSite(map, space, allocation_site);
   if (!maybe_obj->To(&obj)) return maybe_obj;
 
   // Initialize the JSObject.
-  InitializeJSObjectFromMap(JSObject::cast(obj),
-                            FixedArray::cast(properties),
-                            map);
+  InitializeJSObjectFromMap(JSObject::cast(obj), properties, map);
   ASSERT(JSObject::cast(obj)->HasFastElements());
   return obj;
 }
 
 
 MaybeObject* Heap::AllocateJSObject(JSFunction* constructor,
                                     PretenureFlag pretenure) {
   // Allocate the initial map if absent.
   if (!constructor->has_initial_map()) {
     Object* initial_map;
@@ skipping 3483 matching lines @@
   if (FLAG_parallel_recompilation) {
     heap_->relocation_mutex_->Lock();
 #ifdef DEBUG
     heap_->relocation_mutex_locked_by_optimizer_thread_ =
         heap_->isolate()->optimizing_compiler_thread()->IsOptimizerThread();
 #endif  // DEBUG
   }
 }
 
 } }  // namespace v8::internal