Inline array constructor.

src/code-stubs-hydrogen.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 677 matching lines @@
 HValue* CodeStubGraphBuilderBase::BuildArraySingleArgumentConstructor(
     JSArrayBuilder* array_builder) {
   // Smi check and range check on the input arg.
   HValue* constant_one = graph()->GetConstant1();
   HValue* constant_zero = graph()->GetConstant0();
 
   HInstruction* elements = Add<HArgumentsElements>(false);
   HInstruction* argument = Add<HAccessArgumentsAt>(
       elements, constant_one, constant_zero);
 
-  HConstant* max_alloc_length =
-      Add<HConstant>(JSObject::kInitialMaxFastElementArray);
-  const int initial_capacity = JSArray::kPreallocatedArrayElements;
-  HConstant* initial_capacity_node = Add<HConstant>(initial_capacity);
-
-  HInstruction* checked_arg = Add<HBoundsCheck>(argument, max_alloc_length);
-  IfBuilder if_builder(this);
-  if_builder.If<HCompareNumericAndBranch>(checked_arg, constant_zero,
-                                          Token::EQ);
-  if_builder.Then();
-  Push(initial_capacity_node);  // capacity
-  Push(constant_zero);  // length
-  if_builder.Else();
-  Push(checked_arg);  // capacity
-  Push(checked_arg);  // length
-  if_builder.End();
-
-  // Figure out total size
-  HValue* length = Pop();
-  HValue* capacity = Pop();
-  return array_builder->AllocateArray(capacity, length, true);
+  return BuildAllocateArrayFromLength(array_builder, argument);
 }
 
 
 HValue* CodeStubGraphBuilderBase::BuildArrayNArgumentsConstructor(
     JSArrayBuilder* array_builder, ElementsKind kind) {
   // We need to fill with the hole if it's a smi array in the multi-argument
   // case because we might have to bail out while copying arguments into
   // the array because they aren't compatible with a smi array.
   // If it's a double array, no problem, and if it's fast then no
   // problem either because doubles are boxed.
   HValue* length = GetArgumentsLength();
-  bool fill_with_hole = IsFastSmiElementsKind(kind);
+  JSArrayBuilder::FillMode fill_mode = IsFastSmiElementsKind(kind)
+      ? JSArrayBuilder::FILL_WITH_HOLE
+      : JSArrayBuilder::DONT_FILL_WITH_HOLE;

[Toon Verwaest, 2013/11/11 13:59:28]

Technically we don't need to fill this in with the hole. We could just fill it
in with 0 (memset).

[mvstanton, 2013/11/13 14:12:52]

I've added a TODO for this, it's a neat idea.

   HValue* new_object = array_builder->AllocateArray(length,
                                                     length,
-                                                    fill_with_hole);
+                                                    fill_mode);
   HValue* elements = array_builder->GetElementsLocation();
   ASSERT(elements != NULL);
 
   // Now populate the elements correctly.
   LoopBuilder builder(this,
                       context(),
                       LoopBuilder::kPostIncrement);
   HValue* start = graph()->GetConstant0();
   HValue* key = builder.BeginBody(start, length, Token::LT);
   HInstruction* argument_elements = Add<HArgumentsElements>(false);
@@ skipping 513 matching lines @@
   return js_function;
 }
 
 
 Handle<Code> FastNewClosureStub::GenerateCode(Isolate* isolate) {
   return DoGenerateCode(isolate, this);
 }
 
 
 } }  // namespace v8::internal