Preliminary lowering of typed array loads in TF.

src/compiler/access-builder.h

Index: src/compiler/access-builder.h
diff --git a/src/compiler/access-builder.h b/src/compiler/access-builder.h
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+++ b/src/compiler/access-builder.h
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+// 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.
+
+#ifndef V8_COMPILER_ACCESS_BUILDER_H_
+#define V8_COMPILER_ACCESS_BUILDER_H_
+
+#include "src/compiler/simplified-operator.h"
+
+namespace v8 {
+namespace internal {
+namespace compiler {
+
+// This access builder provides a set of static methods constructing commonly
+// used FieldAccess and ElementAccess descriptors. These descriptors server as
+// parameters to simplified load/store operators.
+class AccessBuilder : public AllStatic {
+ public:
+  // Provides access to JSObject::elements() field.
+  static FieldAccess ForJSObjectElements() {
+    return {kTaggedBase, JSObject::kElementsOffset, Handle<Name>(),
+            Type::Internal(), kMachAnyTagged};
+  }
+
+  // Provides access to ExternalArray::external_pointer() field.
+  static FieldAccess ForExternalArrayPointer() {
+    return {kTaggedBase, ExternalArray::kExternalPointerOffset, Handle<Name>(),
+            Type::UntaggedPtr(), kMachPtr};
+  }
+
+  // Provides access to Fixed{type}TypedArray and External{type}Array elements.
+  static ElementAccess ForTypedArrayElement(ExternalArrayType type,
+                                            bool is_external) {
+    BaseTaggedness taggedness = is_external ? kUntaggedBase : kTaggedBase;
+    int header_size = is_external ? 0 : FixedTypedArrayBase::kDataOffset;
+    switch (type) {
+      case kExternalInt8Array:
+        return {taggedness, header_size, Type::Signed32(), kMachInt8};
+      case kExternalUint8Array:
+      case kExternalUint8ClampedArray:
+        return {taggedness, header_size, Type::Unsigned32(), kMachUint8};
+      case kExternalInt16Array:
+        return {taggedness, header_size, Type::Signed32(), kMachInt16};
+      case kExternalUint16Array:
+        return {taggedness, header_size, Type::Unsigned32(), kMachUint16};
+      case kExternalInt32Array:
+        return {taggedness, header_size, Type::Signed32(), kMachInt32};
+      case kExternalUint32Array:
+        return {taggedness, header_size, Type::Unsigned32(), kMachUint32};
+      case kExternalFloat32Array:
+        return {taggedness, header_size, Type::Number(), kRepFloat32};
+      case kExternalFloat64Array:
+        return {taggedness, header_size, Type::Number(), kRepFloat64};
+    }
+    UNREACHABLE();
+    return {kUntaggedBase, 0, Type::None(), kMachNone};
+  }
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(AccessBuilder);
+};
+
+}  // namespace compiler
+}  // namespace internal
+}  // namespace v8
+
+#endif  // V8_COMPILER_ACCESS_BUILDER_H_