[turbofan] Add support for deferred code.

src/compiler/common-operator.h

 // Copyright 2013 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_COMMON_OPERATOR_H_
 #define V8_COMPILER_COMMON_OPERATOR_H_
 
 #include "src/compiler/machine-type.h"
 #include "src/unique.h"
 
 namespace v8 {
 namespace internal {
 
 // Forward declarations.
 class ExternalReference;
 
 
 namespace compiler {
 
 // Forward declarations.
 class CallDescriptor;
 struct CommonOperatorBuilderImpl;
 class Operator;
 
 
+// Prediction hint for branches.
+enum class BranchHint : uint8_t { kNone, kTrue, kFalse };
+
+inline size_t hash_value(BranchHint hint) { return static_cast<size_t>(hint); }
+
+std::ostream& operator<<(std::ostream&, BranchHint);
+
+BranchHint BranchHintOf(const Operator* const);
+
+
 // Flag that describes how to combine the current environment with
 // the output of a node to obtain a framestate for lazy bailout.
 class OutputFrameStateCombine {
  public:
   enum Kind {
     kPushOutput,  // Push the output on the expression stack.
     kPokeAt       // Poke at the given environment location,
                   // counting from the top of the stack.
   };
 
@@ skipping 80 matching lines @@
 
 
 // Interface for building common operators that can be used at any level of IR,
 // including JavaScript, mid-level, and low-level.
 class CommonOperatorBuilder FINAL {
  public:
   explicit CommonOperatorBuilder(Zone* zone);
 
   const Operator* Dead();
   const Operator* End();
-  const Operator* Branch();
+  const Operator* Branch(BranchHint = BranchHint::kNone);
   const Operator* IfTrue();
   const Operator* IfFalse();
   const Operator* Throw();
   const Operator* Return();
 
   const Operator* Start(int num_formal_parameters);
   const Operator* Merge(int controls);
   const Operator* Loop(int controls);
   const Operator* Parameter(int index);
 
@@ skipping 22 matching lines @@
 
   const CommonOperatorBuilderImpl& impl_;
   Zone* const zone_;
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_COMMON_OPERATOR_H_