Re-land FastAccessorBuilder.

src/compiler/fast-accessor-assembler.h

+// Copyright 2015 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_FAST_ACCESSOR_ASSEMBLER_H_
+#define V8_COMPILER_FAST_ACCESSOR_ASSEMBLER_H_
+
+#include <stdint.h>
+#include <vector>
+
+// Clients of this interface shouldn't depend on lots of compiler internals.
+// Do not include anything from src/compiler here!
+#include "include/v8-experimental.h"
+#include "src/base/macros.h"
+#include "src/base/smart-pointers.h"
+#include "src/handles.h"
+
+
+namespace v8 {
+namespace internal {
+
+class Code;
+class Isolate;
+class Zone;
+
+namespace compiler {
+
+class Node;
+class RawMachineAssembler;
+class RawMachineLabel;
+
+
+// This interface "exports" an aggregated subset of RawMachineAssembler, for
+// use by the API to implement Fast Dom Accessors.
+//
+// This interface is made for this single purpose only and does not attempt
+// to implement a general purpose solution. If you need one, please look at
+// RawMachineAssembler instead.
+//
+// The life cycle of a FastAccessorAssembler has two phases:
+// - After creating the instance, you can call an arbitrary sequence of
+//   builder functions to build the desired function.
+// - When done, you can Build() the accessor and query for the build results.
+//
+// You cannot call any result getters before Build() was called & successful;
+// and you cannot call any builder functions after Build() was called.
+class FastAccessorAssembler {
+ public:
+  typedef v8::experimental::FastAccessorBuilder::ValueId ValueId;
+  typedef v8::experimental::FastAccessorBuilder::LabelId LabelId;
+
+  explicit FastAccessorAssembler(Isolate* isolate);
+  ~FastAccessorAssembler();
+
+  // Builder / assembler functions:
+  ValueId IntegerConstant(int int_constant);
+  ValueId GetReceiver();
+  ValueId LoadInternalField(ValueId value_id, int field_no);
+  ValueId LoadValue(ValueId value_id, int offset);
+  ValueId LoadObject(ValueId value_id, int offset);
+
+  // Builder / assembler functions for control flow.
+  void ReturnValue(ValueId value_id);
+  void CheckFlagSetOrReturnNull(ValueId value_id, int mask);
+  void CheckNotZeroOrReturnNull(ValueId value_id);
+
+  // TODO(vogelheim): Implement a C++ callback.
+  //  void CheckNotNullOrCallback(ValueId value_id, ..c++-callback type...,
+  //     ValueId arg1, ValueId arg2, ...);
+
+  LabelId MakeLabel();
+  void SetLabel(LabelId label_id);
+  void CheckNotZeroOrJump(ValueId value_id, LabelId label_id);
+
+  // Assemble the code.
+  MaybeHandle<Code> Build();
+
+ private:
+  ValueId FromRaw(Node* node);
+  LabelId FromRaw(RawMachineLabel* label);
+  Node* FromId(ValueId value) const;
+  RawMachineLabel* FromId(LabelId value) const;
+
+  Zone* zone() { return &zone_; }
+
+  Zone zone_;
+  base::SmartPointer<RawMachineAssembler> assembler_;
+
+  // To prevent exposing the RMA internals to the outside world, we'll map
+  // Node + Label pointers integers wrapped in ValueId and LabelId instances.
+  // These vectors maintain this mapping.
+  std::vector<Node*> nodes_;
+  std::vector<RawMachineLabel*> labels_;
+
+  // Remember the current state for easy error checking. (We prefer to be
+  // strict as this class will be exposed at the API.)
+  enum { kBuilding, kBuilt, kError } state_;
+
+  DISALLOW_COPY_AND_ASSIGN(FastAccessorAssembler);
+};
+
+}  // namespace compiler
+}  // namespace internal
+}  // namespace v8
+
+#endif  // V8_COMPILER_FAST_ACCESSOR_ASSEMBLER_H_