[turbofan] Add SimplifiedOperator::Allocate operator.

src/compiler/access-builder.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/compiler/access-builder.h"
 #include "src/types-inl.h"
 
 namespace v8 {
 namespace internal {
 namespace compiler {
@@ skipping 27 matching lines @@
 
 
 // static
 FieldAccess AccessBuilder::ForJSArrayBufferBackingStore() {
   return {kTaggedBase, JSArrayBuffer::kBackingStoreOffset, MaybeHandle<Name>(),
           Type::UntaggedPointer(), kMachPtr};
 }
 
 
 // static
+FieldAccess AccessBuilder::ForFixedArrayLength() {
+  return {kTaggedBase, FixedArray::kLengthOffset, MaybeHandle<Name>(),
+          Type::TaggedSigned(), kMachAnyTagged};
+}
+
+
+// static
 FieldAccess AccessBuilder::ForExternalArrayPointer() {
   return {kTaggedBase, ExternalArray::kExternalPointerOffset,
           MaybeHandle<Name>(), Type::UntaggedPointer(), kMachPtr};
 }
 
 
 // static
 FieldAccess AccessBuilder::ForMapInstanceType() {
   return {kTaggedBase, Map::kInstanceTypeOffset, Handle<Name>(),
           Type::UntaggedUnsigned8(), kMachUint8};
@@ skipping 81 matching lines @@
       return {kTaggedBase, SeqString::kHeaderSize, Type::Unsigned32(),
               kMachUint16};
   }
   UNREACHABLE();
   return {kUntaggedBase, 0, Type::None(), kMachNone};
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8