[stubs] Cleanup FixedArray copying builtin

src/builtins/builtins-internal.cc

Index: src/builtins/builtins-internal.cc
diff --git a/src/builtins/builtins-internal.cc b/src/builtins/builtins-internal.cc
index 12ab4a94963c0e1926688e6f2887ab8d86b61ace..7204410268dbecc1eb0188a0fc5f9cbc6e267b1d 100644
--- a/src/builtins/builtins-internal.cc
+++ b/src/builtins/builtins-internal.cc
@@ -57,7 +57,6 @@ void Builtins::Generate_CopyFastSmiOrObjectElements(
     CodeStubAssembler* assembler) {
   typedef CodeStubAssembler::Label Label;
   typedef compiler::Node Node;
-  typedef CodeStubAssembler::Variable Variable;
   typedef CopyFastSmiOrObjectElementsDescriptor Descriptor;
 
   Node* object = assembler->Parameter(Descriptor::kObject);
@@ -65,127 +64,39 @@ void Builtins::Generate_CopyFastSmiOrObjectElements(
   // Load the {object}s elements.
   Node* source = assembler->LoadObjectField(object, JSObject::kElementsOffset);
 
-  // Load the {source} length.
-  Node* source_length_tagged =
-      assembler->LoadObjectField(source, FixedArray::kLengthOffset);
-  Node* source_length = assembler->SmiToWord(source_length_tagged);
-
-  // Compute the size of {source} in bytes.
-  Node* source_size = assembler->IntPtrAdd(
-      assembler->WordShl(source_length,
-                         assembler->IntPtrConstant(kPointerSizeLog2)),
-      assembler->IntPtrConstant(FixedArray::kHeaderSize));
+  CodeStubAssembler::ParameterMode mode =
+      assembler->Is64() ? CodeStubAssembler::INTEGER_PARAMETERS
+                        : CodeStubAssembler::SMI_PARAMETERS;
+  Node* length = (mode == CodeStubAssembler::INTEGER_PARAMETERS)
+                     ? assembler->LoadAndUntagFixedArrayBaseLength(source)
+                     : assembler->LoadFixedArrayBaseLength(source);
 
   // Check if we can allocate in new space.
+  ElementsKind kind = FAST_ELEMENTS;
+  int max_elements = FixedArrayBase::GetMaxLengthForNewSpaceAllocation(kind);
   Label if_newspace(assembler), if_oldspace(assembler);
-  assembler->Branch(assembler->UintPtrLessThan(
-                        source_size, assembler->IntPtrConstant(
-                                         Page::kMaxRegularHeapObjectSize)),
-                    &if_newspace, &if_oldspace);
+  assembler->Branch(
+      assembler->UintPtrLessThan(
+          length, assembler->IntPtrOrSmiConstant(max_elements, mode)),
+      &if_newspace, &if_oldspace);
 
   assembler->Bind(&if_newspace);
   {
-    // Allocate the targeting FixedArray in new space.
-    Node* target = assembler->Allocate(source_size);
-    assembler->StoreMapNoWriteBarrier(
-        target, assembler->LoadRoot(Heap::kFixedArrayMapRootIndex));
-    assembler->StoreObjectFieldNoWriteBarrier(target, FixedArray::kLengthOffset,
-                                              source_length_tagged);
-
-    // Compute the limit.
-    Node* limit = assembler->IntPtrSub(
-        source_size, assembler->IntPtrConstant(kHeapObjectTag));
-
-    // Copy the {source} to the {target}.
-    Variable var_offset(assembler, MachineType::PointerRepresentation());
-    Label loop(assembler, &var_offset), done_loop(assembler);
-    var_offset.Bind(
-        assembler->IntPtrConstant(FixedArray::kHeaderSize - kHeapObjectTag));
-    assembler->Goto(&loop);
-    assembler->Bind(&loop);
-    {
-      // Determine the current {offset}.
-      Node* offset = var_offset.value();
-
-      // Check if we are done.
-      assembler->GotoUnless(assembler->UintPtrLessThan(offset, limit),
-                            &done_loop);
-
-      // Load the value from {source}.
-      Node* value = assembler->Load(MachineType::AnyTagged(), source, offset);
-
-      // Store the {value} to the {target} without a write barrier, since we
-      // know that the {target} is allocated in new space.
-      assembler->StoreNoWriteBarrier(MachineRepresentation::kTagged, target,
-                                     offset, value);
-
-      // Increment {offset} and continue.
-      var_offset.Bind(assembler->IntPtrAdd(
-          offset, assembler->IntPtrConstant(kPointerSize)));
-      assembler->Goto(&loop);
-    }
-
-    assembler->Bind(&done_loop);
-    {
-      // Update the {object}s element to {target}.
-      assembler->StoreObjectField(object, JSObject::kElementsOffset, target);
-      assembler->Return(target);
-    }
+    Node* target = assembler->AllocateFixedArray(kind, length, mode);
+    assembler->CopyFixedArrayElements(kind, source, target, length,
+                                      SKIP_WRITE_BARRIER, mode);
+    assembler->StoreObjectField(object, JSObject::kElementsOffset, target);
+    assembler->Return(target);
   }
 
   assembler->Bind(&if_oldspace);
   {
-    // Allocate the targeting FixedArray in old space
-    // (maybe even in large object space).
-    Node* flags = assembler->SmiConstant(
-        Smi::FromInt(AllocateDoubleAlignFlag::encode(false) |
-                     AllocateTargetSpace::encode(AllocationSpace::OLD_SPACE)));
-    Node* source_size_tagged = assembler->SmiFromWord(source_size);
-    Node* target = assembler->CallRuntime(Runtime::kAllocateInTargetSpace,
-                                          assembler->NoContextConstant(),
-                                          source_size_tagged, flags);
-    assembler->StoreMapNoWriteBarrier(
-        target, assembler->LoadRoot(Heap::kFixedArrayMapRootIndex));
-    assembler->StoreObjectFieldNoWriteBarrier(target, FixedArray::kLengthOffset,
-                                              source_length_tagged);
-
-    // Compute the limit.
-    Node* limit = assembler->IntPtrSub(
-        source_size, assembler->IntPtrConstant(kHeapObjectTag));
-
-    // Copy the {source} to the {target}.
-    Variable var_offset(assembler, MachineType::PointerRepresentation());
-    Label loop(assembler, &var_offset), done_loop(assembler);
-    var_offset.Bind(
-        assembler->IntPtrConstant(FixedArray::kHeaderSize - kHeapObjectTag));
-    assembler->Goto(&loop);
-    assembler->Bind(&loop);
-    {
-      // Determine the current {offset}.
-      Node* offset = var_offset.value();
-
-      // Check if we are done.
-      assembler->GotoUnless(assembler->UintPtrLessThan(offset, limit),
-                            &done_loop);
-
-      // Load the value from {source}.
-      Node* value = assembler->Load(MachineType::AnyTagged(), source, offset);
-
-      // Store the {value} to the {target} with a proper write barrier.
-      assembler->Store(MachineRepresentation::kTagged, target, offset, value);
-
-      // Increment {offset} and continue.
-      var_offset.Bind(assembler->IntPtrAdd(
-          offset, assembler->IntPtrConstant(kPointerSize)));
-      assembler->Goto(&loop);
-    }
-
-    assembler->Bind(&done_loop);
-    {
-      // Update the {object}s element to {target}.
-      assembler->StoreObjectField(object, JSObject::kElementsOffset, target);
-      assembler->Return(target);
-    }
+    Node* target = assembler->AllocateFixedArray(
+        kind, length, mode, compiler::CodeAssembler::kPretenured);
+    assembler->CopyFixedArrayElements(kind, source, target, length,
+                                      UPDATE_WRITE_BARRIER, mode);
+    assembler->StoreObjectField(object, JSObject::kElementsOffset, target);
+    assembler->Return(target);
   }
 }