A64: Implement and use FillFields

src/a64/lithium-codegen-a64.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 1499 matching lines @@
     __ Allocate(size, result, temp1, temp2, deferred->entry(), flags);
   } else {
     Register size = ToRegister32(instr->size());
     __ Sxtw(size.X(), size);
     __ Allocate(size.X(), result, temp1, temp2, deferred->entry(), flags);
   }
 
   __ Bind(deferred->exit());
 
   if (instr->hydrogen()->MustPrefillWithFiller()) {
+    Register filler_count = temp1;
+    Register filler = temp2;
+    Register untagged_result = ToRegister(instr->temp3());
+
     if (instr->size()->IsConstantOperand()) {
       int32_t size = ToInteger32(LConstantOperand::cast(instr->size()));
-      __ Mov(temp1, size - kPointerSize);
+      __ Mov(filler_count, size / kPointerSize);
     } else {
-      __ Sub(temp1.W(), ToRegister32(instr->size()), kPointerSize);
+      __ Lsr(filler_count.W(), ToRegister32(instr->size()), kPointerSizeLog2);
     }
-    __ Sub(result, result, kHeapObjectTag);
 
-    // TODO(jbramley): Optimize this loop using stp.
-    Label loop;
-    __ Bind(&loop);
-    __ Mov(temp2, Operand(isolate()->factory()->one_pointer_filler_map()));
-    __ Str(temp2, MemOperand(result, temp1));
-    __ Subs(temp1, temp1, kPointerSize);
-    __ B(ge, &loop);
-
-    __ Add(result, result, kHeapObjectTag);
+    __ Sub(untagged_result, result, kHeapObjectTag);
+    __ Mov(filler, Operand(isolate()->factory()->one_pointer_filler_map()));
+    __ FillFields(untagged_result, filler_count, filler);
+  } else {
+    ASSERT(instr->temp3() == NULL);
   }
 }
 
 
 void LCodeGen::DoDeferredAllocate(LAllocate* instr) {
   // TODO(3095996): Get rid of this. For now, we need to make the
   // result register contain a valid pointer because it is already
   // contained in the register pointer map.
   __ Mov(ToRegister(instr->result()), Operand(Smi::FromInt(0)));
 
@@ skipping 4305 matching lines @@
   __ Bind(&out_of_object);
   __ Ldr(result, FieldMemOperand(object, JSObject::kPropertiesOffset));
   // Index is equal to negated out of object property index plus 1.
   __ Sub(result, result, Operand::UntagSmiAndScale(index, kPointerSizeLog2));
   __ Ldr(result, FieldMemOperand(result,
                                  FixedArray::kHeaderSize - kPointerSize));
   __ Bind(&done);
 }
 
 } }  // namespace v8::internal