// 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/typer.h"

#include <iomanip>

#include "src/base/flags.h"
#include "src/bootstrapper.h"
#include "src/compiler/common-operator.h"
#include "src/compiler/graph-reducer.h"
#include "src/compiler/js-operator.h"
#include "src/compiler/linkage.h"
#include "src/compiler/loop-variable-optimizer.h"
#include "src/compiler/node-properties.h"
#include "src/compiler/node.h"
#include "src/compiler/operation-typer.h"
#include "src/compiler/simplified-operator.h"
#include "src/compiler/type-cache.h"
#include "src/objects-inl.h"

namespace v8 {
namespace internal {
namespace compiler {

class Typer::Decorator final : public GraphDecorator {
 public:
  explicit Decorator(Typer* typer) : typer_(typer) {}
  void Decorate(Node* node) final;

 private:
  Typer* const typer_;
};

Typer::Typer(Isolate* isolate, Flags flags, Graph* graph)
    : isolate_(isolate),
      flags_(flags),
      graph_(graph),
      decorator_(nullptr),
      cache_(TypeCache::Get()),
      operation_typer_(isolate, zone()) {
  Zone* zone = this->zone();
  Factory* const factory = isolate->factory();

  singleton_empty_string_ = Type::HeapConstant(factory->empty_string(), zone);
  singleton_false_ = operation_typer_.singleton_false();
  singleton_true_ = operation_typer_.singleton_true();
  falsish_ = Type::Union(
      Type::Undetectable(),
      Type::Union(Type::Union(singleton_false_, cache_.kZeroish, zone),
                  Type::Union(singleton_empty_string_, Type::Hole(), zone),
                  zone),
      zone);
  truish_ = Type::Union(
      singleton_true_,
      Type::Union(Type::DetectableReceiver(), Type::Symbol(), zone), zone);

  decorator_ = new (zone) Decorator(this);
  graph_->AddDecorator(decorator_);
}


Typer::~Typer() {
  graph_->RemoveDecorator(decorator_);
}


class Typer::Visitor : public Reducer {
 public:
  explicit Visitor(Typer* typer, LoopVariableOptimizer* induction_vars)
      : typer_(typer),
        induction_vars_(induction_vars),
        weakened_nodes_(typer->zone()) {}

  const char* reducer_name() const override { return "Typer"; }

  Reduction Reduce(Node* node) override {
    if (node->op()->ValueOutputCount() == 0) return NoChange();
    switch (node->opcode()) {
#define DECLARE_CASE(x) \
  case IrOpcode::k##x:  \
    return UpdateType(node, TypeBinaryOp(node, x##Typer));
      JS_SIMPLE_BINOP_LIST(DECLARE_CASE)
#undef DECLARE_CASE

#define DECLARE_CASE(x) \
  case IrOpcode::k##x:  \
    return UpdateType(node, Type##x(node));
      DECLARE_CASE(Start)
      DECLARE_CASE(IfException)
      // VALUE_OP_LIST without JS_SIMPLE_BINOP_LIST:
      COMMON_OP_LIST(DECLARE_CASE)
      SIMPLIFIED_COMPARE_BINOP_LIST(DECLARE_CASE)
      SIMPLIFIED_OTHER_OP_LIST(DECLARE_CASE)
      JS_SIMPLE_UNOP_LIST(DECLARE_CASE)
      JS_OBJECT_OP_LIST(DECLARE_CASE)
      JS_CONTEXT_OP_LIST(DECLARE_CASE)
      JS_OTHER_OP_LIST(DECLARE_CASE)
#undef DECLARE_CASE

#define DECLARE_CASE(x) \
  case IrOpcode::k##x:  \
    return UpdateType(node, TypeBinaryOp(node, x));
      SIMPLIFIED_NUMBER_BINOP_LIST(DECLARE_CASE)
      SIMPLIFIED_SPECULATIVE_NUMBER_BINOP_LIST(DECLARE_CASE)
#undef DECLARE_CASE

#define DECLARE_CASE(x) \
  case IrOpcode::k##x:  \
    return UpdateType(node, TypeUnaryOp(node, x));
      SIMPLIFIED_NUMBER_UNOP_LIST(DECLARE_CASE)
      SIMPLIFIED_SPECULATIVE_NUMBER_UNOP_LIST(DECLARE_CASE)
#undef DECLARE_CASE

#define DECLARE_CASE(x) case IrOpcode::k##x:
      DECLARE_CASE(Loop)
      DECLARE_CASE(Branch)
      DECLARE_CASE(IfTrue)
      DECLARE_CASE(IfFalse)
      DECLARE_CASE(IfSuccess)
      DECLARE_CASE(Switch)
      DECLARE_CASE(IfValue)
      DECLARE_CASE(IfDefault)
      DECLARE_CASE(Merge)
      DECLARE_CASE(Deoptimize)
      DECLARE_CASE(DeoptimizeIf)
      DECLARE_CASE(DeoptimizeUnless)
      DECLARE_CASE(TrapIf)
      DECLARE_CASE(TrapUnless)
      DECLARE_CASE(Return)
      DECLARE_CASE(TailCall)
      DECLARE_CASE(Terminate)
      DECLARE_CASE(OsrNormalEntry)
      DECLARE_CASE(OsrLoopEntry)
      DECLARE_CASE(Throw)
      DECLARE_CASE(End)
      SIMPLIFIED_CHANGE_OP_LIST(DECLARE_CASE)
      SIMPLIFIED_CHECKED_OP_LIST(DECLARE_CASE)
      MACHINE_SIMD_OP_LIST(DECLARE_CASE)
      MACHINE_OP_LIST(DECLARE_CASE)
#undef DECLARE_CASE
      break;
    }
    return NoChange();
  }

  Type* TypeNode(Node* node) {
    switch (node->opcode()) {
#define DECLARE_CASE(x) \
      case IrOpcode::k##x: return TypeBinaryOp(node, x##Typer);
      JS_SIMPLE_BINOP_LIST(DECLARE_CASE)
#undef DECLARE_CASE

#define DECLARE_CASE(x) case IrOpcode::k##x: return Type##x(node);
      DECLARE_CASE(Start)
      DECLARE_CASE(IfException)
      // VALUE_OP_LIST without JS_SIMPLE_BINOP_LIST:
      COMMON_OP_LIST(DECLARE_CASE)
      SIMPLIFIED_COMPARE_BINOP_LIST(DECLARE_CASE)
      SIMPLIFIED_OTHER_OP_LIST(DECLARE_CASE)
      JS_SIMPLE_UNOP_LIST(DECLARE_CASE)
      JS_OBJECT_OP_LIST(DECLARE_CASE)
      JS_CONTEXT_OP_LIST(DECLARE_CASE)
      JS_OTHER_OP_LIST(DECLARE_CASE)
#undef DECLARE_CASE

#define DECLARE_CASE(x) \
  case IrOpcode::k##x:  \
    return TypeBinaryOp(node, x);
      SIMPLIFIED_NUMBER_BINOP_LIST(DECLARE_CASE)
      SIMPLIFIED_SPECULATIVE_NUMBER_BINOP_LIST(DECLARE_CASE)
#undef DECLARE_CASE

#define DECLARE_CASE(x) \
  case IrOpcode::k##x:  \
    return TypeUnaryOp(node, x);
      SIMPLIFIED_NUMBER_UNOP_LIST(DECLARE_CASE)
      SIMPLIFIED_SPECULATIVE_NUMBER_UNOP_LIST(DECLARE_CASE)
#undef DECLARE_CASE

#define DECLARE_CASE(x) case IrOpcode::k##x:
      DECLARE_CASE(Loop)
      DECLARE_CASE(Branch)
      DECLARE_CASE(IfTrue)
      DECLARE_CASE(IfFalse)
      DECLARE_CASE(IfSuccess)
      DECLARE_CASE(Switch)
      DECLARE_CASE(IfValue)
      DECLARE_CASE(IfDefault)
      DECLARE_CASE(Merge)
      DECLARE_CASE(Deoptimize)
      DECLARE_CASE(DeoptimizeIf)
      DECLARE_CASE(DeoptimizeUnless)
      DECLARE_CASE(TrapIf)
      DECLARE_CASE(TrapUnless)
      DECLARE_CASE(Return)
      DECLARE_CASE(TailCall)
      DECLARE_CASE(Terminate)
      DECLARE_CASE(OsrNormalEntry)
      DECLARE_CASE(OsrLoopEntry)
      DECLARE_CASE(Throw)
      DECLARE_CASE(End)
      SIMPLIFIED_CHANGE_OP_LIST(DECLARE_CASE)
      SIMPLIFIED_CHECKED_OP_LIST(DECLARE_CASE)
      MACHINE_SIMD_OP_LIST(DECLARE_CASE)
      MACHINE_OP_LIST(DECLARE_CASE)
#undef DECLARE_CASE
      break;
    }
    UNREACHABLE();
  }

  Type* TypeConstant(Handle<Object> value);

 private:
  Typer* typer_;
  LoopVariableOptimizer* induction_vars_;
  ZoneSet<NodeId> weakened_nodes_;

#define DECLARE_METHOD(x) inline Type* Type##x(Node* node);
  DECLARE_METHOD(Start)
  DECLARE_METHOD(IfException)
  COMMON_OP_LIST(DECLARE_METHOD)
  SIMPLIFIED_COMPARE_BINOP_LIST(DECLARE_METHOD)
  SIMPLIFIED_OTHER_OP_LIST(DECLARE_METHOD)
  JS_OP_LIST(DECLARE_METHOD)
#undef DECLARE_METHOD

  Type* TypeOrNone(Node* node) {
    return NodeProperties::IsTyped(node) ? NodeProperties::GetType(node)
                                         : Type::None();
  }

  Type* Operand(Node* node, int i) {
    Node* operand_node = NodeProperties::GetValueInput(node, i);
    return TypeOrNone(operand_node);
  }

  Type* Weaken(Node* node, Type* current_type, Type* previous_type);

  Zone* zone() { return typer_->zone(); }
  Isolate* isolate() { return typer_->isolate(); }
  Graph* graph() { return typer_->graph(); }

  void SetWeakened(NodeId node_id) { weakened_nodes_.insert(node_id); }
  bool IsWeakened(NodeId node_id) {
    return weakened_nodes_.find(node_id) != weakened_nodes_.end();
  }

  typedef Type* (*UnaryTyperFun)(Type*, Typer* t);
  typedef Type* (*BinaryTyperFun)(Type*, Type*, Typer* t);

  Type* TypeUnaryOp(Node* node, UnaryTyperFun);
  Type* TypeBinaryOp(Node* node, BinaryTyperFun);

  static Type* BinaryNumberOpTyper(Type* lhs, Type* rhs, Typer* t,
                                   BinaryTyperFun f);

  enum ComparisonOutcomeFlags {
    kComparisonTrue = 1,
    kComparisonFalse = 2,
    kComparisonUndefined = 4
  };
  typedef base::Flags<ComparisonOutcomeFlags> ComparisonOutcome;

  static ComparisonOutcome Invert(ComparisonOutcome, Typer*);
  static Type* FalsifyUndefined(ComparisonOutcome, Typer*);

  static Type* BitwiseNot(Type*, Typer*);
  static Type* Decrement(Type*, Typer*);
  static Type* Increment(Type*, Typer*);
  static Type* Negate(Type*, Typer*);

  static Type* ToPrimitive(Type*, Typer*);
  static Type* ToBoolean(Type*, Typer*);
  static Type* ToInteger(Type*, Typer*);
  static Type* ToLength(Type*, Typer*);
  static Type* ToName(Type*, Typer*);
  static Type* ToNumber(Type*, Typer*);
  static Type* ToNumeric(Type*, Typer*);
  static Type* ToObject(Type*, Typer*);
  static Type* ToString(Type*, Typer*);
#define DECLARE_METHOD(Name)                \
  static Type* Name(Type* type, Typer* t) { \
    return t->operation_typer_.Name(type);  \
  }
  SIMPLIFIED_NUMBER_UNOP_LIST(DECLARE_METHOD)
  SIMPLIFIED_SPECULATIVE_NUMBER_UNOP_LIST(DECLARE_METHOD)
#undef DECLARE_METHOD
#define DECLARE_METHOD(Name)                          \
  static Type* Name(Type* lhs, Type* rhs, Typer* t) { \
    return t->operation_typer_.Name(lhs, rhs);        \
  }
  SIMPLIFIED_NUMBER_BINOP_LIST(DECLARE_METHOD)
  SIMPLIFIED_SPECULATIVE_NUMBER_BINOP_LIST(DECLARE_METHOD)
#undef DECLARE_METHOD

  static Type* ObjectIsArrayBufferView(Type*, Typer*);
  static Type* ObjectIsBigInt(Type*, Typer*);
  static Type* ObjectIsCallable(Type*, Typer*);
  static Type* ObjectIsConstructor(Type*, Typer*);
  static Type* ObjectIsDetectableCallable(Type*, Typer*);
  static Type* ObjectIsMinusZero(Type*, Typer*);
  static Type* ObjectIsNaN(Type*, Typer*);
  static Type* ObjectIsNonCallable(Type*, Typer*);
  static Type* ObjectIsNumber(Type*, Typer*);
  static Type* ObjectIsReceiver(Type*, Typer*);
  static Type* ObjectIsSmi(Type*, Typer*);
  static Type* ObjectIsString(Type*, Typer*);
  static Type* ObjectIsSymbol(Type*, Typer*);
  static Type* ObjectIsUndetectable(Type*, Typer*);

  static ComparisonOutcome JSCompareTyper(Type*, Type*, Typer*);
  static ComparisonOutcome NumberCompareTyper(Type*, Type*, Typer*);

#define DECLARE_METHOD(x) static Type* x##Typer(Type*, Type*, Typer*);
  JS_SIMPLE_BINOP_LIST(DECLARE_METHOD)
#undef DECLARE_METHOD

  static Type* JSCallTyper(Type*, Typer*);

  static Type* NumberEqualTyper(Type*, Type*, Typer*);
  static Type* NumberLessThanTyper(Type*, Type*, Typer*);
  static Type* NumberLessThanOrEqualTyper(Type*, Type*, Typer*);
  static Type* ReferenceEqualTyper(Type*, Type*, Typer*);
  static Type* SameValueTyper(Type*, Type*, Typer*);
  static Type* StringFromCharCodeTyper(Type*, Typer*);
  static Type* StringFromCodePointTyper(Type*, Typer*);

  Reduction UpdateType(Node* node, Type* current) {
    if (NodeProperties::IsTyped(node)) {
      // Widen the type of a previously typed node.
      Type* previous = NodeProperties::GetType(node);
      if (node->opcode() == IrOpcode::kPhi ||
          node->opcode() == IrOpcode::kInductionVariablePhi) {
        // Speed up termination in the presence of range types:
        current = Weaken(node, current, previous);
      }

      CHECK(previous->Is(current));

      NodeProperties::SetType(node, current);
      if (!current->Is(previous)) {
        // If something changed, revisit all uses.
        return Changed(node);
      }
      return NoChange();
    } else {
      // No previous type, simply update the type.
      NodeProperties::SetType(node, current);
      return Changed(node);
    }
  }
};

void Typer::Run() { Run(NodeVector(zone()), nullptr); }

void Typer::Run(const NodeVector& roots,
                LoopVariableOptimizer* induction_vars) {
  if (induction_vars != nullptr) {
    induction_vars->ChangeToInductionVariablePhis();
  }
  Visitor visitor(this, induction_vars);
  GraphReducer graph_reducer(zone(), graph());
  graph_reducer.AddReducer(&visitor);
  for (Node* const root : roots) graph_reducer.ReduceNode(root);
  graph_reducer.ReduceGraph();

  if (induction_vars != nullptr) {
    induction_vars->ChangeToPhisAndInsertGuards();
  }
}

void Typer::Decorator::Decorate(Node* node) {
  if (node->op()->ValueOutputCount() > 0) {
    // Only eagerly type-decorate nodes with known input types.
    // Other cases will generally require a proper fixpoint iteration with Run.
    bool is_typed = NodeProperties::IsTyped(node);
    if (is_typed || NodeProperties::AllValueInputsAreTyped(node)) {
      Visitor typing(typer_, nullptr);
      Type* type = typing.TypeNode(node);
      if (is_typed) {
        type = Type::Intersect(type, NodeProperties::GetType(node),
                               typer_->zone());
      }
      NodeProperties::SetType(node, type);
    }
  }
}


// -----------------------------------------------------------------------------

// Helper functions that lift a function f on types to a function on bounds,
// and uses that to type the given node.  Note that f is never called with None
// as an argument.


Type* Typer::Visitor::TypeUnaryOp(Node* node, UnaryTyperFun f) {
  Type* input = Operand(node, 0);
  return input->IsNone() ? Type::None() : f(input, typer_);
}

Type* Typer::Visitor::TypeBinaryOp(Node* node, BinaryTyperFun f) {
  Type* left = Operand(node, 0);
  Type* right = Operand(node, 1);
  return left->IsNone() || right->IsNone() ? Type::None()
                                           : f(left, right, typer_);
}

Type* Typer::Visitor::BinaryNumberOpTyper(Type* lhs, Type* rhs, Typer* t,
                                          BinaryTyperFun f) {
  lhs = ToNumeric(lhs, t);
  rhs = ToNumeric(rhs, t);
  bool lhs_is_number = lhs->Is(Type::Number());
  bool rhs_is_number = rhs->Is(Type::Number());
  if (lhs_is_number && rhs_is_number) {
    return f(lhs, rhs, t);
  }
  if (lhs_is_number || rhs_is_number) {
    return Type::Number();
  }
  if (lhs->Is(Type::BigInt()) || rhs->Is(Type::BigInt())) {
    return Type::BigInt();
  }
  return Type::Numeric();
}

Typer::Visitor::ComparisonOutcome Typer::Visitor::Invert(
    ComparisonOutcome outcome, Typer* t) {
  ComparisonOutcome result(0);
  if ((outcome & kComparisonUndefined) != 0) result |= kComparisonUndefined;
  if ((outcome & kComparisonTrue) != 0) result |= kComparisonFalse;
  if ((outcome & kComparisonFalse) != 0) result |= kComparisonTrue;
  return result;
}

Type* Typer::Visitor::FalsifyUndefined(ComparisonOutcome outcome, Typer* t) {
  if ((outcome & kComparisonFalse) != 0 ||
      (outcome & kComparisonUndefined) != 0) {
    return (outcome & kComparisonTrue) != 0 ? Type::Boolean()
                                            : t->singleton_false_;
  }
  // Type should be non empty, so we know it should be true.
  DCHECK_NE(0, outcome & kComparisonTrue);
  return t->singleton_true_;
}

Type* Typer::Visitor::BitwiseNot(Type* type, Typer* t) {
  type = ToNumeric(type, t);
  if (type->Is(Type::Number())) {
    return NumberBitwiseXor(type, t->cache_.kSingletonMinusOne, t);
  }
  return Type::Numeric();
}

Type* Typer::Visitor::Decrement(Type* type, Typer* t) {
  type = ToNumeric(type, t);
  if (type->Is(Type::Number())) {
    return NumberSubtract(type, t->cache_.kSingletonOne, t);
  }
  return Type::Numeric();
}

Type* Typer::Visitor::Increment(Type* type, Typer* t) {
  type = ToNumeric(type, t);
  if (type->Is(Type::Number())) {
    return NumberAdd(type, t->cache_.kSingletonOne, t);
  }
  return Type::Numeric();
}

Type* Typer::Visitor::Negate(Type* type, Typer* t) {
  type = ToNumeric(type, t);
  if (type->Is(Type::Number())) {
    return NumberMultiply(type, t->cache_.kSingletonMinusOne, t);
  }
  return Type::Numeric();
}

// Type conversion.

Type* Typer::Visitor::ToPrimitive(Type* type, Typer* t) {
  if (type->Is(Type::Primitive()) && !type->Maybe(Type::Receiver())) {
    return type;
  }
  return Type::Primitive();
}


Type* Typer::Visitor::ToBoolean(Type* type, Typer* t) {
  if (type->Is(Type::Boolean())) return type;
  if (type->Is(t->falsish_)) return t->singleton_false_;
  if (type->Is(t->truish_)) return t->singleton_true_;
  if (type->Is(Type::Number())) {
    return t->operation_typer()->NumberToBoolean(type);
  }
  return Type::Boolean();
}


// static
Type* Typer::Visitor::ToInteger(Type* type, Typer* t) {
  // ES6 section 7.1.4 ToInteger ( argument )
  type = ToNumber(type, t);
  if (type->Is(t->cache_.kIntegerOrMinusZero)) return type;
  if (type->Is(t->cache_.kIntegerOrMinusZeroOrNaN)) {
    return Type::Union(
        Type::Intersect(type, t->cache_.kIntegerOrMinusZero, t->zone()),
        t->cache_.kSingletonZero, t->zone());
  }
  return t->cache_.kIntegerOrMinusZero;
}


// static
Type* Typer::Visitor::ToLength(Type* type, Typer* t) {
  // ES6 section 7.1.15 ToLength ( argument )
  type = ToInteger(type, t);
  if (type->IsNone()) return type;
  double min = type->Min();
  double max = type->Max();
  if (max <= 0.0) {
    return Type::NewConstant(0, t->zone());
  }
  if (min >= kMaxSafeInteger) {
    return Type::NewConstant(kMaxSafeInteger, t->zone());
  }
  if (min <= 0.0) min = 0.0;
  if (max >= kMaxSafeInteger) max = kMaxSafeInteger;
  return Type::Range(min, max, t->zone());
}


// static
Type* Typer::Visitor::ToName(Type* type, Typer* t) {
  // ES6 section 7.1.14 ToPropertyKey ( argument )
  type = ToPrimitive(type, t);
  if (type->Is(Type::Name())) return type;
  if (type->Maybe(Type::Symbol())) return Type::Name();
  return ToString(type, t);
}


// static
Type* Typer::Visitor::ToNumber(Type* type, Typer* t) {
  return t->operation_typer_.ToNumber(type);
}

// static
Type* Typer::Visitor::ToNumeric(Type* type, Typer* t) {
  return t->operation_typer_.ToNumeric(type);
}

// static
Type* Typer::Visitor::ToObject(Type* type, Typer* t) {
  // ES6 section 7.1.13 ToObject ( argument )
  if (type->Is(Type::Receiver())) return type;
  if (type->Is(Type::Primitive())) return Type::OtherObject();
  if (!type->Maybe(Type::OtherUndetectable())) {
    return Type::DetectableReceiver();
  }
  return Type::Receiver();
}


// static
Type* Typer::Visitor::ToString(Type* type, Typer* t) {
  // ES6 section 7.1.12 ToString ( argument )
  type = ToPrimitive(type, t);
  if (type->Is(Type::String())) return type;
  return Type::String();
}

// Type checks.

Type* Typer::Visitor::ObjectIsArrayBufferView(Type* type, Typer* t) {
  // TODO(turbofan): Introduce a Type::ArrayBufferView?
  if (!type->Maybe(Type::OtherObject())) return t->singleton_false_;
  return Type::Boolean();
}

Type* Typer::Visitor::ObjectIsBigInt(Type* type, Typer* t) {
  if (type->Is(Type::BigInt())) return t->singleton_true_;
  if (!type->Maybe(Type::BigInt())) return t->singleton_false_;
  return Type::Boolean();
}

Type* Typer::Visitor::ObjectIsCallable(Type* type, Typer* t) {
  if (type->Is(Type::Callable())) return t->singleton_true_;
  if (!type->Maybe(Type::Callable())) return t->singleton_false_;
  return Type::Boolean();
}

Type* Typer::Visitor::ObjectIsConstructor(Type* type, Typer* t) {
  // TODO(turbofan): Introduce a Type::Constructor?
  if (!type->Maybe(Type::Callable())) return t->singleton_false_;
  return Type::Boolean();
}

Type* Typer::Visitor::ObjectIsDetectableCallable(Type* type, Typer* t) {
  if (type->Is(Type::DetectableCallable())) return t->singleton_true_;
  if (!type->Maybe(Type::DetectableCallable())) return t->singleton_false_;
  return Type::Boolean();
}

Type* Typer::Visitor::ObjectIsMinusZero(Type* type, Typer* t) {
  if (type->Is(Type::MinusZero())) return t->singleton_true_;
  if (!type->Maybe(Type::MinusZero())) return t->singleton_false_;
  return Type::Boolean();
}

Type* Typer::Visitor::ObjectIsNaN(Type* type, Typer* t) {
  if (type->Is(Type::NaN())) return t->singleton_true_;
  if (!type->Maybe(Type::NaN())) return t->singleton_false_;
  return Type::Boolean();
}

Type* Typer::Visitor::ObjectIsNonCallable(Type* type, Typer* t) {
  if (type->Is(Type::NonCallable())) return t->singleton_true_;
  if (!type->Maybe(Type::NonCallable())) return t->singleton_false_;
  return Type::Boolean();
}

Type* Typer::Visitor::ObjectIsNumber(Type* type, Typer* t) {
  if (type->Is(Type::Number())) return t->singleton_true_;
  if (!type->Maybe(Type::Number())) return t->singleton_false_;
  return Type::Boolean();
}


Type* Typer::Visitor::ObjectIsReceiver(Type* type, Typer* t) {
  if (type->Is(Type::Receiver())) return t->singleton_true_;
  if (!type->Maybe(Type::Receiver())) return t->singleton_false_;
  return Type::Boolean();
}


Type* Typer::Visitor::ObjectIsSmi(Type* type, Typer* t) {
  if (!type->Maybe(Type::SignedSmall())) return t->singleton_false_;
  return Type::Boolean();
}

Type* Typer::Visitor::ObjectIsString(Type* type, Typer* t) {
  if (type->Is(Type::String())) return t->singleton_true_;
  if (!type->Maybe(Type::String())) return t->singleton_false_;
  return Type::Boolean();
}

Type* Typer::Visitor::ObjectIsSymbol(Type* type, Typer* t) {
  if (type->Is(Type::Symbol())) return t->singleton_true_;
  if (!type->Maybe(Type::Symbol())) return t->singleton_false_;
  return Type::Boolean();
}

Type* Typer::Visitor::ObjectIsUndetectable(Type* type, Typer* t) {
  if (type->Is(Type::Undetectable())) return t->singleton_true_;
  if (!type->Maybe(Type::Undetectable())) return t->singleton_false_;
  return Type::Boolean();
}


// -----------------------------------------------------------------------------


// Control operators.

Type* Typer::Visitor::TypeStart(Node* node) { return Type::Internal(); }

Type* Typer::Visitor::TypeIfException(Node* node) {
  return Type::NonInternal();
}

// Common operators.

Type* Typer::Visitor::TypeParameter(Node* node) {
  Node* const start = node->InputAt(0);
  DCHECK_EQ(IrOpcode::kStart, start->opcode());
  int const parameter_count = start->op()->ValueOutputCount() - 4;
  DCHECK_LE(1, parameter_count);
  int const index = ParameterIndexOf(node->op());
  if (index == Linkage::kJSCallClosureParamIndex) {
    return Type::Function();
  } else if (index == 0) {
    if (typer_->flags() & Typer::kThisIsReceiver) {
      return Type::Receiver();
    } else {
      // Parameter[this] can be the_hole for derived class constructors.
      return Type::Union(Type::Hole(), Type::NonInternal(), typer_->zone());
    }
  } else if (index == Linkage::GetJSCallNewTargetParamIndex(parameter_count)) {
    if (typer_->flags() & Typer::kNewTargetIsReceiver) {
      return Type::Receiver();
    } else {
      return Type::Union(Type::Receiver(), Type::Undefined(), typer_->zone());
    }
  } else if (index == Linkage::GetJSCallArgCountParamIndex(parameter_count)) {
    return Type::Range(0.0, Code::kMaxArguments, typer_->zone());
  } else if (index == Linkage::GetJSCallContextParamIndex(parameter_count)) {
    return Type::OtherInternal();
  }
  return Type::NonInternal();
}

Type* Typer::Visitor::TypeOsrValue(Node* node) { return Type::Any(); }

Type* Typer::Visitor::TypeRetain(Node* node) {
  UNREACHABLE();
}

Type* Typer::Visitor::TypeInt32Constant(Node* node) {
  UNREACHABLE();
}

Type* Typer::Visitor::TypeInt64Constant(Node* node) {
  UNREACHABLE();
}

Type* Typer::Visitor::TypeRelocatableInt32Constant(Node* node) {
  UNREACHABLE();
}

Type* Typer::Visitor::TypeRelocatableInt64Constant(Node* node) {
  UNREACHABLE();
}

Type* Typer::Visitor::TypeFloat32Constant(Node* node) {
  UNREACHABLE();
}

Type* Typer::Visitor::TypeFloat64Constant(Node* node) {
  UNREACHABLE();
}

Type* Typer::Visitor::TypeNumberConstant(Node* node) {
  double number = OpParameter<double>(node);
  return Type::NewConstant(number, zone());
}

Type* Typer::Visitor::TypeHeapConstant(Node* node) {
  return TypeConstant(OpParameter<Handle<HeapObject>>(node));
}

Type* Typer::Visitor::TypeExternalConstant(Node* node) {
  return Type::ExternalPointer();
}

Type* Typer::Visitor::TypePointerConstant(Node* node) {
  return Type::ExternalPointer();
}

Type* Typer::Visitor::TypeSelect(Node* node) {
  return Type::Union(Operand(node, 1), Operand(node, 2), zone());
}

Type* Typer::Visitor::TypePhi(Node* node) {
  int arity = node->op()->ValueInputCount();
  Type* type = Operand(node, 0);
  for (int i = 1; i < arity; ++i) {
    type = Type::Union(type, Operand(node, i), zone());
  }
  return type;
}

Type* Typer::Visitor::TypeInductionVariablePhi(Node* node) {
  int arity = NodeProperties::GetControlInput(node)->op()->ControlInputCount();
  DCHECK_EQ(IrOpcode::kLoop, NodeProperties::GetControlInput(node)->opcode());
  DCHECK_EQ(2, NodeProperties::GetControlInput(node)->InputCount());

  Type* initial_type = Operand(node, 0);
  Type* increment_type = Operand(node, 2);

  // We only handle integer induction variables (otherwise ranges
  // do not apply and we cannot do anything).
  if (!initial_type->Is(typer_->cache_.kInteger) ||
      !increment_type->Is(typer_->cache_.kInteger)) {
    // Fallback to normal phi typing, but ensure monotonicity.
    // (Unfortunately, without baking in the previous type, monotonicity might
    // be violated because we might not yet have retyped the incrementing
    // operation even though the increment's type might been already reflected
    // in the induction variable phi.)
    Type* type = NodeProperties::IsTyped(node) ? NodeProperties::GetType(node)
                                               : Type::None();
    for (int i = 0; i < arity; ++i) {
      type = Type::Union(type, Operand(node, i), zone());
    }
    return type;
  }
  // If we do not have enough type information for the initial value or
  // the increment, just return the initial value's type.
  if (initial_type->IsNone() ||
      increment_type->Is(typer_->cache_.kSingletonZero)) {
    return initial_type;
  }

  // Now process the bounds.
  auto res = induction_vars_->induction_variables().find(node->id());
  DCHECK(res != induction_vars_->induction_variables().end());
  InductionVariable* induction_var = res->second;

  InductionVariable::ArithmeticType arithmetic_type = induction_var->Type();

  double min = -V8_INFINITY;
  double max = V8_INFINITY;

  double increment_min;
  double increment_max;
  if (arithmetic_type == InductionVariable::ArithmeticType::kAddition) {
    increment_min = increment_type->Min();
    increment_max = increment_type->Max();
  } else {
    DCHECK_EQ(InductionVariable::ArithmeticType::kSubtraction, arithmetic_type);
    increment_min = -increment_type->Max();
    increment_max = -increment_type->Min();
  }

  if (increment_min >= 0) {
    // increasing sequence
    min = initial_type->Min();
    for (auto bound : induction_var->upper_bounds()) {
      Type* bound_type = TypeOrNone(bound.bound);
      // If the type is not an integer, just skip the bound.
      if (!bound_type->Is(typer_->cache_.kInteger)) continue;
      // If the type is not inhabited, then we can take the initial value.
      if (bound_type->IsNone()) {
        max = initial_type->Max();
        break;
      }
      double bound_max = bound_type->Max();
      if (bound.kind == InductionVariable::kStrict) {
        bound_max -= 1;
      }
      max = std::min(max, bound_max + increment_max);
    }
    // The upper bound must be at least the initial value's upper bound.
    max = std::max(max, initial_type->Max());
  } else if (increment_max <= 0) {
    // decreasing sequence
    max = initial_type->Max();
    for (auto bound : induction_var->lower_bounds()) {
      Type* bound_type = TypeOrNone(bound.bound);
      // If the type is not an integer, just skip the bound.
      if (!bound_type->Is(typer_->cache_.kInteger)) continue;
      // If the type is not inhabited, then we can take the initial value.
      if (bound_type->IsNone()) {
        min = initial_type->Min();
        break;
      }
      double bound_min = bound_type->Min();
      if (bound.kind == InductionVariable::kStrict) {
        bound_min += 1;
      }
      min = std::max(min, bound_min + increment_min);
    }
    // The lower bound must be at most the initial value's lower bound.
    min = std::min(min, initial_type->Min());
  } else {
    // Shortcut: If the increment can be both positive and negative,
    // the variable can go arbitrarily far, so just return integer.
    return typer_->cache_.kInteger;
  }
  if (FLAG_trace_turbo_loop) {
    OFStream os(stdout);
    os << std::setprecision(10);
    os << "Loop (" << NodeProperties::GetControlInput(node)->id()
       << ") variable bounds in "
       << (arithmetic_type == InductionVariable::ArithmeticType::kAddition
               ? "addition"
               : "subtraction")
       << " for phi " << node->id() << ": (" << min << ", " << max << ")\n";
  }
  return Type::Range(min, max, typer_->zone());
}

Type* Typer::Visitor::TypeEffectPhi(Node* node) {
  UNREACHABLE();
}

Type* Typer::Visitor::TypeLoopExit(Node* node) {
  UNREACHABLE();
}

Type* Typer::Visitor::TypeLoopExitValue(Node* node) { return Operand(node, 0); }

Type* Typer::Visitor::TypeLoopExitEffect(Node* node) {
  UNREACHABLE();
}

Type* Typer::Visitor::TypeEnsureWritableFastElements(Node* node) {
  return Operand(node, 1);
}

Type* Typer::Visitor::TypeMaybeGrowFastElements(Node* node) {
  return Operand(node, 1);
}

Type* Typer::Visitor::TypeTransitionElementsKind(Node* node) {
  UNREACHABLE();
}

Type* Typer::Visitor::TypeCheckpoint(Node* node) {
  UNREACHABLE();
}

Type* Typer::Visitor::TypeBeginRegion(Node* node) {
  UNREACHABLE();
}


Type* Typer::Visitor::TypeFinishRegion(Node* node) { return Operand(node, 0); }


Type* Typer::Visitor::TypeFrameState(Node* node) {
  // TODO(rossberg): Ideally FrameState wouldn't have a value output.
  return Type::Internal();
}

Type* Typer::Visitor::TypeStateValues(Node* node) { return Type::Internal(); }

Type* Typer::Visitor::TypeTypedStateValues(Node* node) {
  return Type::Internal();
}

Type* Typer::Visitor::TypeObjectId(Node* node) { UNREACHABLE(); }

Type* Typer::Visitor::TypeArgumentsElementsState(Node* node) {
  return Type::Internal();
}

Type* Typer::Visitor::TypeArgumentsLengthState(Node* node) {
  return Type::Internal();
}

Type* Typer::Visitor::TypeObjectState(Node* node) { return Type::Internal(); }

Type* Typer::Visitor::TypeTypedObjectState(Node* node) {
  return Type::Internal();
}

Type* Typer::Visitor::TypeCall(Node* node) { return Type::Any(); }

Type* Typer::Visitor::TypeCallWithCallerSavedRegisters(Node* node) {
  UNREACHABLE();
}

Type* Typer::Visitor::TypeProjection(Node* node) {
  Type* const type = Operand(node, 0);
  if (type->Is(Type::None())) return Type::None();
  int const index = static_cast<int>(ProjectionIndexOf(node->op()));
  if (type->IsTuple() && index < type->AsTuple()->Arity()) {
    return type->AsTuple()->Element(index);
  }
  return Type::Any();
}

Type* Typer::Visitor::TypeMapGuard(Node* node) { UNREACHABLE(); }

Type* Typer::Visitor::TypeTypeGuard(Node* node) {
  Type* const type = Operand(node, 0);
  return typer_->operation_typer()->TypeTypeGuard(node->op(), type);
}

Type* Typer::Visitor::TypeDead(Node* node) { return Type::None(); }

Type* Typer::Visitor::TypeDeadValue(Node* node) { return Type::None(); }

Type* Typer::Visitor::TypeUnreachable(Node* node) { return Type::None(); }

// JS comparison operators.


Type* Typer::Visitor::JSEqualTyper(Type* lhs, Type* rhs, Typer* t) {
  if (lhs->Is(Type::NaN()) || rhs->Is(Type::NaN())) return t->singleton_false_;
  if (lhs->Is(Type::NullOrUndefined()) && rhs->Is(Type::NullOrUndefined())) {
    return t->singleton_true_;
  }
  if (lhs->Is(Type::Number()) && rhs->Is(Type::Number()) &&
      (lhs->Max() < rhs->Min() || lhs->Min() > rhs->Max())) {
    return t->singleton_false_;
  }
  if (lhs->IsHeapConstant() && rhs->Is(lhs)) {
    // Types are equal and are inhabited only by a single semantic value,
    // which is not nan due to the earlier check.
    return t->singleton_true_;
  }
  return Type::Boolean();
}

Type* Typer::Visitor::JSStrictEqualTyper(Type* lhs, Type* rhs, Typer* t) {
  return t->operation_typer()->StrictEqual(lhs, rhs);
}

// The EcmaScript specification defines the four relational comparison operators
// (<, <=, >=, >) with the help of a single abstract one.  It behaves like <
// but returns undefined when the inputs cannot be compared.
// We implement the typing analogously.
Typer::Visitor::ComparisonOutcome Typer::Visitor::JSCompareTyper(Type* lhs,
                                                                 Type* rhs,
                                                                 Typer* t) {
  lhs = ToPrimitive(lhs, t);
  rhs = ToPrimitive(rhs, t);
  if (lhs->Maybe(Type::String()) && rhs->Maybe(Type::String())) {
    return ComparisonOutcome(kComparisonTrue) |
           ComparisonOutcome(kComparisonFalse);
  }
  lhs = ToNumeric(lhs, t);
  rhs = ToNumeric(rhs, t);
  if (lhs->Is(Type::Number()) && rhs->Is(Type::Number())) {
    return NumberCompareTyper(lhs, rhs, t);
  }
  return ComparisonOutcome(kComparisonTrue) |
         ComparisonOutcome(kComparisonFalse) |
         ComparisonOutcome(kComparisonUndefined);
}

Typer::Visitor::ComparisonOutcome Typer::Visitor::NumberCompareTyper(Type* lhs,
                                                                     Type* rhs,
                                                                     Typer* t) {
  DCHECK(lhs->Is(Type::Number()));
  DCHECK(rhs->Is(Type::Number()));

  // Shortcut for NaNs.
  if (lhs->Is(Type::NaN()) || rhs->Is(Type::NaN())) return kComparisonUndefined;

  ComparisonOutcome result;
  if (lhs->IsHeapConstant() && rhs->Is(lhs)) {
    // Types are equal and are inhabited only by a single semantic value.
    result = kComparisonFalse;
  } else if (lhs->Min() >= rhs->Max()) {
    result = kComparisonFalse;
  } else if (lhs->Max() < rhs->Min()) {
    result = kComparisonTrue;
  } else {
    // We cannot figure out the result, return both true and false. (We do not
    // have to return undefined because that cannot affect the result of
    // FalsifyUndefined.)
    return ComparisonOutcome(kComparisonTrue) |
           ComparisonOutcome(kComparisonFalse);
  }
  // Add the undefined if we could see NaN.
  if (lhs->Maybe(Type::NaN()) || rhs->Maybe(Type::NaN())) {
    result |= kComparisonUndefined;
  }
  return result;
}


Type* Typer::Visitor::JSLessThanTyper(Type* lhs, Type* rhs, Typer* t) {
  return FalsifyUndefined(JSCompareTyper(lhs, rhs, t), t);
}


Type* Typer::Visitor::JSGreaterThanTyper(Type* lhs, Type* rhs, Typer* t) {
  return FalsifyUndefined(JSCompareTyper(rhs, lhs, t), t);
}


Type* Typer::Visitor::JSLessThanOrEqualTyper(Type* lhs, Type* rhs, Typer* t) {
  return FalsifyUndefined(Invert(JSCompareTyper(rhs, lhs, t), t), t);
}


Type* Typer::Visitor::JSGreaterThanOrEqualTyper(
    Type* lhs, Type* rhs, Typer* t) {
  return FalsifyUndefined(Invert(JSCompareTyper(lhs, rhs, t), t), t);
}

// JS bitwise operators.


Type* Typer::Visitor::JSBitwiseOrTyper(Type* lhs, Type* rhs, Typer* t) {
  return BinaryNumberOpTyper(lhs, rhs, t, NumberBitwiseOr);
}

Type* Typer::Visitor::JSBitwiseAndTyper(Type* lhs, Type* rhs, Typer* t) {
  return BinaryNumberOpTyper(lhs, rhs, t, NumberBitwiseAnd);
}

Type* Typer::Visitor::JSBitwiseXorTyper(Type* lhs, Type* rhs, Typer* t) {
  return BinaryNumberOpTyper(lhs, rhs, t, NumberBitwiseXor);
}

Type* Typer::Visitor::JSShiftLeftTyper(Type* lhs, Type* rhs, Typer* t) {
  return BinaryNumberOpTyper(lhs, rhs, t, NumberShiftLeft);
}

Type* Typer::Visitor::JSShiftRightTyper(Type* lhs, Type* rhs, Typer* t) {
  return BinaryNumberOpTyper(lhs, rhs, t, NumberShiftRight);
}


Type* Typer::Visitor::JSShiftRightLogicalTyper(Type* lhs, Type* rhs, Typer* t) {
  return NumberShiftRightLogical(ToNumber(lhs, t), ToNumber(rhs, t), t);
}


// JS arithmetic operators.

Type* Typer::Visitor::JSAddTyper(Type* lhs, Type* rhs, Typer* t) {
  lhs = ToPrimitive(lhs, t);
  rhs = ToPrimitive(rhs, t);
  if (lhs->Maybe(Type::String()) || rhs->Maybe(Type::String())) {
    if (lhs->Is(Type::String()) || rhs->Is(Type::String())) {
      return Type::String();
    } else {
      return Type::NumericOrString();
    }
  }
  // The addition must be numeric.
  return BinaryNumberOpTyper(lhs, rhs, t, NumberAdd);
}

Type* Typer::Visitor::JSSubtractTyper(Type* lhs, Type* rhs, Typer* t) {
  return BinaryNumberOpTyper(lhs, rhs, t, NumberSubtract);
}

Type* Typer::Visitor::JSMultiplyTyper(Type* lhs, Type* rhs, Typer* t) {
  return BinaryNumberOpTyper(lhs, rhs, t, NumberMultiply);
}

Type* Typer::Visitor::JSDivideTyper(Type* lhs, Type* rhs, Typer* t) {
  return BinaryNumberOpTyper(lhs, rhs, t, NumberDivide);
}

Type* Typer::Visitor::JSModulusTyper(Type* lhs, Type* rhs, Typer* t) {
  return BinaryNumberOpTyper(lhs, rhs, t, NumberModulus);
}

Type* Typer::Visitor::JSExponentiateTyper(Type* lhs, Type* rhs, Typer* t) {
  // TODO(neis): Refine using BinaryNumberOpTyper?
  return Type::Numeric();
}

// JS unary operators.

Type* Typer::Visitor::TypeJSBitwiseNot(Node* node) {
  return TypeUnaryOp(node, BitwiseNot);
}

Type* Typer::Visitor::TypeJSDecrement(Node* node) {
  return TypeUnaryOp(node, Decrement);
}

Type* Typer::Visitor::TypeJSIncrement(Node* node) {
  return TypeUnaryOp(node, Increment);
}

Type* Typer::Visitor::TypeJSNegate(Node* node) {
  return TypeUnaryOp(node, Negate);
}

Type* Typer::Visitor::TypeClassOf(Node* node) {
  return Type::InternalizedStringOrNull();
}

Type* Typer::Visitor::TypeTypeOf(Node* node) {
  return Type::InternalizedString();
}


// JS conversion operators.

Type* Typer::Visitor::TypeToBoolean(Node* node) {
  return TypeUnaryOp(node, ToBoolean);
}

Type* Typer::Visitor::TypeJSToInteger(Node* node) {
  return TypeUnaryOp(node, ToInteger);
}

Type* Typer::Visitor::TypeJSToLength(Node* node) {
  return TypeUnaryOp(node, ToLength);
}

Type* Typer::Visitor::TypeJSToName(Node* node) {
  return TypeUnaryOp(node, ToName);
}

Type* Typer::Visitor::TypeJSToNumber(Node* node) {
  return TypeUnaryOp(node, ToNumber);
}

Type* Typer::Visitor::TypeJSToNumeric(Node* node) {
  return TypeUnaryOp(node, ToNumeric);
}

Type* Typer::Visitor::TypeJSToObject(Node* node) {
  return TypeUnaryOp(node, ToObject);
}

Type* Typer::Visitor::TypeJSToString(Node* node) {
  return TypeUnaryOp(node, ToString);
}

// JS object operators.


Type* Typer::Visitor::TypeJSCreate(Node* node) { return Type::Object(); }


Type* Typer::Visitor::TypeJSCreateArguments(Node* node) {
  switch (CreateArgumentsTypeOf(node->op())) {
    case CreateArgumentsType::kRestParameter:
      return Type::Array();
    case CreateArgumentsType::kMappedArguments:
    case CreateArgumentsType::kUnmappedArguments:
      return Type::OtherObject();
  }
  UNREACHABLE();
}

Type* Typer::Visitor::TypeJSCreateArray(Node* node) { return Type::Array(); }

Type* Typer::Visitor::TypeJSCreateBoundFunction(Node* node) {
  return Type::BoundFunction();
}

Type* Typer::Visitor::TypeJSCreateGeneratorObject(Node* node) {
  return Type::OtherObject();
}

Type* Typer::Visitor::TypeJSCreateClosure(Node* node) {
  return Type::Function();
}


Type* Typer::Visitor::TypeJSCreateIterResultObject(Node* node) {
  return Type::OtherObject();
}

Type* Typer::Visitor::TypeJSCreateKeyValueArray(Node* node) {
  return Type::OtherObject();
}

Type* Typer::Visitor::TypeJSCreateLiteralArray(Node* node) {
  return Type::Array();
}

Type* Typer::Visitor::TypeJSCreateEmptyLiteralArray(Node* node) {
  return Type::Array();
}

Type* Typer::Visitor::TypeJSCreateLiteralObject(Node* node) {
  return Type::OtherObject();
}

Type* Typer::Visitor::TypeJSCreateEmptyLiteralObject(Node* node) {
  return Type::OtherObject();
}

Type* Typer::Visitor::TypeJSCreateLiteralRegExp(Node* node) {
  return Type::OtherObject();
}


Type* Typer::Visitor::TypeJSLoadProperty(Node* node) {
  return Type::NonInternal();
}


Type* Typer::Visitor::TypeJSLoadNamed(Node* node) {
  return Type::NonInternal();
}

Type* Typer::Visitor::TypeJSLoadGlobal(Node* node) {
  return Type::NonInternal();
}

// Returns a somewhat larger range if we previously assigned
// a (smaller) range to this node. This is used  to speed up
// the fixpoint calculation in case there appears to be a loop
// in the graph. In the current implementation, we are
// increasing the limits to the closest power of two.
Type* Typer::Visitor::Weaken(Node* node, Type* current_type,
                             Type* previous_type) {
  static const double kWeakenMinLimits[] = {
      0.0, -1073741824.0, -2147483648.0, -4294967296.0, -8589934592.0,
      -17179869184.0, -34359738368.0, -68719476736.0, -137438953472.0,
      -274877906944.0, -549755813888.0, -1099511627776.0, -2199023255552.0,
      -4398046511104.0, -8796093022208.0, -17592186044416.0, -35184372088832.0,
      -70368744177664.0, -140737488355328.0, -281474976710656.0,
      -562949953421312.0};
  static const double kWeakenMaxLimits[] = {
      0.0, 1073741823.0, 2147483647.0, 4294967295.0, 8589934591.0,
      17179869183.0, 34359738367.0, 68719476735.0, 137438953471.0,
      274877906943.0, 549755813887.0, 1099511627775.0, 2199023255551.0,
      4398046511103.0, 8796093022207.0, 17592186044415.0, 35184372088831.0,
      70368744177663.0, 140737488355327.0, 281474976710655.0,
      562949953421311.0};
  STATIC_ASSERT(arraysize(kWeakenMinLimits) == arraysize(kWeakenMaxLimits));

  // If the types have nothing to do with integers, return the types.
  Type* const integer = typer_->cache_.kInteger;
  if (!previous_type->Maybe(integer)) {
    return current_type;
  }
  DCHECK(current_type->Maybe(integer));

  Type* current_integer = Type::Intersect(current_type, integer, zone());
  Type* previous_integer = Type::Intersect(previous_type, integer, zone());

  // Once we start weakening a node, we should always weaken.
  if (!IsWeakened(node->id())) {
    // Only weaken if there is range involved; we should converge quickly
    // for all other types (the exception is a union of many constants,
    // but we currently do not increase the number of constants in unions).
    Type* previous = previous_integer->GetRange();
    Type* current = current_integer->GetRange();
    if (current == nullptr || previous == nullptr) {
      return current_type;
    }
    // Range is involved => we are weakening.
    SetWeakened(node->id());
  }

  double current_min = current_integer->Min();
  double new_min = current_min;
  // Find the closest lower entry in the list of allowed
  // minima (or negative infinity if there is no such entry).
  if (current_min != previous_integer->Min()) {
    new_min = -V8_INFINITY;
    for (double const min : kWeakenMinLimits) {
      if (min <= current_min) {
        new_min = min;
        break;
      }
    }
  }

  double current_max = current_integer->Max();
  double new_max = current_max;
  // Find the closest greater entry in the list of allowed
  // maxima (or infinity if there is no such entry).
  if (current_max != previous_integer->Max()) {
    new_max = V8_INFINITY;
    for (double const max : kWeakenMaxLimits) {
      if (max >= current_max) {
        new_max = max;
        break;
      }
    }
  }

  return Type::Union(current_type,
                     Type::Range(new_min, new_max, typer_->zone()),
                     typer_->zone());
}


Type* Typer::Visitor::TypeJSStoreProperty(Node* node) {
  UNREACHABLE();
}


Type* Typer::Visitor::TypeJSStoreNamed(Node* node) {
  UNREACHABLE();
}


Type* Typer::Visitor::TypeJSStoreGlobal(Node* node) {
  UNREACHABLE();
}

Type* Typer::Visitor::TypeJSStoreNamedOwn(Node* node) {
  UNREACHABLE();
}

Type* Typer::Visitor::TypeJSStoreDataPropertyInLiteral(Node* node) {
  UNREACHABLE();
}

Type* Typer::Visitor::TypeJSDeleteProperty(Node* node) {
  return Type::Boolean();
}

Type* Typer::Visitor::TypeJSHasProperty(Node* node) { return Type::Boolean(); }

// JS instanceof operator.

Type* Typer::Visitor::JSHasInPrototypeChainTyper(Type* lhs, Type* rhs,
                                                 Typer* t) {
  return Type::Boolean();
}

Type* Typer::Visitor::JSInstanceOfTyper(Type* lhs, Type* rhs, Typer* t) {
  return Type::Boolean();
}

Type* Typer::Visitor::JSOrdinaryHasInstanceTyper(Type* lhs, Type* rhs,
                                                 Typer* t) {
  return Type::Boolean();
}

Type* Typer::Visitor::TypeJSGetSuperConstructor(Node* node) {
  return Type::Callable();
}

// JS context operators.


Type* Typer::Visitor::TypeJSLoadContext(Node* node) {
  ContextAccess const& access = ContextAccessOf(node->op());
  switch (access.index()) {
    case Context::PREVIOUS_INDEX:
    case Context::NATIVE_CONTEXT_INDEX:
      return Type::OtherInternal();
    case Context::CLOSURE_INDEX:
      return Type::Function();
    default:
      return Type::Any();
  }
}


Type* Typer::Visitor::TypeJSStoreContext(Node* node) {
  UNREACHABLE();
}


Type* Typer::Visitor::TypeJSCreateFunctionContext(Node* node) {
  return Type::OtherInternal();
}

Type* Typer::Visitor::TypeJSCreateCatchContext(Node* node) {
  return Type::OtherInternal();
}

Type* Typer::Visitor::TypeJSCreateWithContext(Node* node) {
  return Type::OtherInternal();
}

Type* Typer::Visitor::TypeJSCreateBlockContext(Node* node) {
  return Type::OtherInternal();
}

// JS other operators.

Type* Typer::Visitor::TypeJSConstructForwardVarargs(Node* node) {
  return Type::Receiver();
}

Type* Typer::Visitor::TypeJSConstruct(Node* node) { return Type::Receiver(); }

Type* Typer::Visitor::TypeJSConstructWithArrayLike(Node* node) {
  return Type::Receiver();
}

Type* Typer::Visitor::TypeJSConstructWithSpread(Node* node) {
  return Type::Receiver();
}

Type* Typer::Visitor::JSCallTyper(Type* fun, Typer* t) {
  if (fun->IsHeapConstant() && fun->AsHeapConstant()->Value()->IsJSFunction()) {
    Handle<JSFunction> function =
        Handle<JSFunction>::cast(fun->AsHeapConstant()->Value());
    if (function->shared()->HasBuiltinFunctionId()) {
      switch (function->shared()->builtin_function_id()) {
        case kMathRandom:
          return Type::PlainNumber();
        case kMathFloor:
        case kMathCeil:
        case kMathRound:
        case kMathTrunc:
          return t->cache_.kIntegerOrMinusZeroOrNaN;
        // Unary math functions.
        case kMathAbs:
        case kMathExp:
        case kMathExpm1:
          return Type::Union(Type::PlainNumber(), Type::NaN(), t->zone());
        case kMathAcos:
        case kMathAcosh:
        case kMathAsin:
        case kMathAsinh:
        case kMathAtan:
        case kMathAtanh:
        case kMathCbrt:
        case kMathCos:
        case kMathFround:
        case kMathLog:
        case kMathLog1p:
        case kMathLog10:
        case kMathLog2:
        case kMathSin:
        case kMathSqrt:
        case kMathTan:
          return Type::Number();
        case kMathSign:
          return t->cache_.kMinusOneToOneOrMinusZeroOrNaN;
        // Binary math functions.
        case kMathAtan2:
        case kMathPow:
        case kMathMax:
        case kMathMin:
          return Type::Number();
        case kMathImul:
          return Type::Signed32();
        case kMathClz32:
          return t->cache_.kZeroToThirtyTwo;
        // Date functions.
        case kDateNow:
          return t->cache_.kTimeValueType;
        case kDateGetDate:
          return t->cache_.kJSDateDayType;
        case kDateGetDay:
          return t->cache_.kJSDateWeekdayType;
        case kDateGetFullYear:
          return t->cache_.kJSDateYearType;
        case kDateGetHours:
          return t->cache_.kJSDateHourType;
        case kDateGetMilliseconds:
          return Type::Union(Type::Range(0.0, 999.0, t->zone()), Type::NaN(),
                             t->zone());
        case kDateGetMinutes:
          return t->cache_.kJSDateMinuteType;
        case kDateGetMonth:
          return t->cache_.kJSDateMonthType;
        case kDateGetSeconds:
          return t->cache_.kJSDateSecondType;
        case kDateGetTime:
          return t->cache_.kJSDateValueType;

        // Symbol functions.
        case kSymbolConstructor:
          return Type::Symbol();

        // BigInt functions.
        case kBigIntConstructor:
          return Type::BigInt();

        // Number functions.
        case kNumberConstructor:
          return Type::Number();
        case kNumberIsFinite:
        case kNumberIsInteger:
        case kNumberIsNaN:
        case kNumberIsSafeInteger:
          return Type::Boolean();
        case kNumberParseFloat:
          return Type::Number();
        case kNumberParseInt:
          return t->cache_.kIntegerOrMinusZeroOrNaN;
        case kNumberToString:
          return Type::String();

        // String functions.
        case kStringConstructor:
          return Type::String();
        case kStringCharCodeAt:
          return Type::Union(Type::Range(0, kMaxUInt16, t->zone()), Type::NaN(),
                             t->zone());
        case kStringCharAt:
          return Type::String();
        case kStringCodePointAt:
          return Type::Union(Type::Range(0.0, String::kMaxCodePoint, t->zone()),
                             Type::Undefined(), t->zone());
        case kStringConcat:
        case kStringFromCharCode:
        case kStringFromCodePoint:
          return Type::String();
        case kStringIndexOf:
        case kStringLastIndexOf:
          return Type::Range(-1.0, String::kMaxLength, t->zone());
        case kStringEndsWith:
        case kStringIncludes:
          return Type::Boolean();
        case kStringRaw:
        case kStringRepeat:
        case kStringSlice:
          return Type::String();
        case kStringStartsWith:
          return Type::Boolean();
        case kStringSubstr:
        case kStringSubstring:
        case kStringToLowerCase:
        case kStringToString:
        case kStringToUpperCase:
        case kStringTrim:
        case kStringTrimLeft:
        case kStringTrimRight:
        case kStringValueOf:
          return Type::String();

        case kStringIterator:
        case kStringIteratorNext:
          return Type::OtherObject();

        case kArrayEntries:
        case kArrayKeys:
        case kArrayValues:
        case kTypedArrayEntries:
        case kTypedArrayKeys:
        case kTypedArrayValues:
        case kArrayIteratorNext:
        case kMapIteratorNext:
        case kSetIteratorNext:
          return Type::OtherObject();
        case kTypedArrayToStringTag:
          return Type::Union(Type::InternalizedString(), Type::Undefined(),
                             t->zone());

        // Array functions.
        case kArrayIsArray:
          return Type::Boolean();
        case kArrayConcat:
          return Type::Receiver();
        case kArrayEvery:
          return Type::Boolean();
        case kArrayFill:
        case kArrayFilter:
          return Type::Receiver();
        case kArrayFindIndex:
          return Type::Range(-1, kMaxSafeInteger, t->zone());
        case kArrayForEach:
          return Type::Undefined();
        case kArrayIncludes:
          return Type::Boolean();
        case kArrayIndexOf:
          return Type::Range(-1, kMaxSafeInteger, t->zone());
        case kArrayJoin:
          return Type::String();
        case kArrayLastIndexOf:
          return Type::Range(-1, kMaxSafeInteger, t->zone());
        case kArrayMap:
          return Type::Receiver();
        case kArrayPush:
          return t->cache_.kPositiveSafeInteger;
        case kArrayReverse:
        case kArraySlice:
          return Type::Receiver();
        case kArraySome:
          return Type::Boolean();
        case kArraySplice:
          return Type::Receiver();
        case kArrayUnshift:
          return t->cache_.kPositiveSafeInteger;

        // ArrayBuffer functions.
        case kArrayBufferIsView:
          return Type::Boolean();

        // Object functions.
        case kObjectAssign:
          return Type::Receiver();
        case kObjectCreate:
          return Type::OtherObject();
        case kObjectIs:
        case kObjectHasOwnProperty:
        case kObjectIsPrototypeOf:
          return Type::Boolean();
        case kObjectToString:
          return Type::String();

        // RegExp functions.
        case kRegExpCompile:
          return Type::OtherObject();
        case kRegExpExec:
          return Type::Union(Type::Array(), Type::Null(), t->zone());
        case kRegExpTest:
          return Type::Boolean();
        case kRegExpToString:
          return Type::String();

        // Function functions.
        case kFunctionBind:
          return Type::BoundFunction();
        case kFunctionHasInstance:
          return Type::Boolean();

        // Global functions.
        case kGlobalDecodeURI:
        case kGlobalDecodeURIComponent:
        case kGlobalEncodeURI:
        case kGlobalEncodeURIComponent:
        case kGlobalEscape:
        case kGlobalUnescape:
          return Type::String();
        case kGlobalIsFinite:
        case kGlobalIsNaN:
          return Type::Boolean();

        // Map functions.
        case kMapClear:
        case kMapForEach:
          return Type::Undefined();
        case kMapDelete:
        case kMapHas:
          return Type::Boolean();
        case kMapEntries:
        case kMapKeys:
        case kMapSet:
        case kMapValues:
          return Type::OtherObject();

        // Set functions.
        case kSetAdd:
        case kSetEntries:
        case kSetValues:
          return Type::OtherObject();
        case kSetClear:
        case kSetForEach:
          return Type::Undefined();
        case kSetDelete:
        case kSetHas:
          return Type::Boolean();

        // WeakMap functions.
        case kWeakMapDelete:
        case kWeakMapHas:
          return Type::Boolean();
        case kWeakMapSet:
          return Type::OtherObject();

        // WeakSet functions.
        case kWeakSetAdd:
          return Type::OtherObject();
        case kWeakSetDelete:
        case kWeakSetHas:
          return Type::Boolean();
        default:
          break;
      }
    }
  }
  return Type::NonInternal();
}

Type* Typer::Visitor::TypeJSCallForwardVarargs(Node* node) {
  return TypeUnaryOp(node, JSCallTyper);
}

Type* Typer::Visitor::TypeJSCall(Node* node) {
  // TODO(bmeurer): We could infer better types if we wouldn't ignore the
  // argument types for the JSCallTyper above.
  return TypeUnaryOp(node, JSCallTyper);
}

Type* Typer::Visitor::TypeJSCallWithArrayLike(Node* node) {
  return TypeUnaryOp(node, JSCallTyper);
}

Type* Typer::Visitor::TypeJSCallWithSpread(Node* node) {
  return TypeUnaryOp(node, JSCallTyper);
}

Type* Typer::Visitor::TypeJSCallRuntime(Node* node) {
  switch (CallRuntimeParametersOf(node->op()).id()) {
    case Runtime::kInlineIsJSReceiver:
      return TypeUnaryOp(node, ObjectIsReceiver);
    case Runtime::kInlineIsSmi:
      return TypeUnaryOp(node, ObjectIsSmi);
    case Runtime::kInlineIsArray:
    case Runtime::kInlineIsDate:
    case Runtime::kInlineIsTypedArray:
    case Runtime::kInlineIsRegExp:
      return Type::Boolean();
    case Runtime::kInlineCreateIterResultObject:
      return Type::OtherObject();
    case Runtime::kInlineStringCharFromCode:
      return Type::String();
    case Runtime::kInlineToInteger:
      return TypeUnaryOp(node, ToInteger);
    case Runtime::kInlineToLength:
      return TypeUnaryOp(node, ToLength);
    case Runtime::kInlineToNumber:
      return TypeUnaryOp(node, ToNumber);
    case Runtime::kInlineToObject:
      return TypeUnaryOp(node, ToObject);
    case Runtime::kInlineToString:
      return TypeUnaryOp(node, ToString);
    case Runtime::kInlineClassOf:
      return Type::InternalizedStringOrNull();
    case Runtime::kHasInPrototypeChain:
      return Type::Boolean();
    default:
      break;
  }
  // TODO(turbofan): This should be Type::NonInternal(), but unfortunately we
  // have a few weird runtime calls that return the hole or even FixedArrays;
  // change this once those weird runtime calls have been removed.
  return Type::Any();
}


Type* Typer::Visitor::TypeJSForInEnumerate(Node* node) {
  return Type::OtherInternal();
}

Type* Typer::Visitor::TypeJSForInNext(Node* node) {
  return Type::Union(Type::String(), Type::Undefined(), zone());
}


Type* Typer::Visitor::TypeJSForInPrepare(Node* node) {
  STATIC_ASSERT(Map::EnumLengthBits::kMax <= FixedArray::kMaxLength);
  Type* const cache_type =
      Type::Union(Type::SignedSmall(), Type::OtherInternal(), zone());
  Type* const cache_array = Type::OtherInternal();
  Type* const cache_length = typer_->cache_.kFixedArrayLengthType;
  return Type::Tuple(cache_type, cache_array, cache_length, zone());
}


Type* Typer::Visitor::TypeJSLoadMessage(Node* node) { return Type::Any(); }


Type* Typer::Visitor::TypeJSStoreMessage(Node* node) {
  UNREACHABLE();
}

Type* Typer::Visitor::TypeJSLoadModule(Node* node) { return Type::Any(); }

Type* Typer::Visitor::TypeJSStoreModule(Node* node) {
  UNREACHABLE();
}

Type* Typer::Visitor::TypeJSGeneratorStore(Node* node) {
  UNREACHABLE();
}

Type* Typer::Visitor::TypeJSGeneratorRestoreContinuation(Node* node) {
  return Type::SignedSmall();
}

Type* Typer::Visitor::TypeJSGeneratorRestoreRegister(Node* node) {
  return Type::Any();
}

Type* Typer::Visitor::TypeJSGeneratorRestoreInputOrDebugPos(Node* node) {
  return Type::Any();
}

Type* Typer::Visitor::TypeJSStackCheck(Node* node) { return Type::Any(); }

Type* Typer::Visitor::TypeJSDebugger(Node* node) { return Type::Any(); }

// Simplified operators.

Type* Typer::Visitor::TypeBooleanNot(Node* node) { return Type::Boolean(); }

// static
Type* Typer::Visitor::NumberEqualTyper(Type* lhs, Type* rhs, Typer* t) {
  return JSEqualTyper(ToNumber(lhs, t), ToNumber(rhs, t), t);
}

// static
Type* Typer::Visitor::NumberLessThanTyper(Type* lhs, Type* rhs, Typer* t) {
  return FalsifyUndefined(
      NumberCompareTyper(ToNumber(lhs, t), ToNumber(rhs, t), t), t);
}

// static
Type* Typer::Visitor::NumberLessThanOrEqualTyper(Type* lhs, Type* rhs,
                                                 Typer* t) {
  return FalsifyUndefined(
      Invert(JSCompareTyper(ToNumber(rhs, t), ToNumber(lhs, t), t), t), t);
}

Type* Typer::Visitor::TypeNumberEqual(Node* node) {
  return TypeBinaryOp(node, NumberEqualTyper);
}

Type* Typer::Visitor::TypeNumberLessThan(Node* node) {
  return TypeBinaryOp(node, NumberLessThanTyper);
}

Type* Typer::Visitor::TypeNumberLessThanOrEqual(Node* node) {
  return TypeBinaryOp(node, NumberLessThanOrEqualTyper);
}

Type* Typer::Visitor::TypeSpeculativeNumberEqual(Node* node) {
  return TypeBinaryOp(node, NumberEqualTyper);
}

Type* Typer::Visitor::TypeSpeculativeNumberLessThan(Node* node) {
  return TypeBinaryOp(node, NumberLessThanTyper);
}

Type* Typer::Visitor::TypeSpeculativeNumberLessThanOrEqual(Node* node) {
  return TypeBinaryOp(node, NumberLessThanOrEqualTyper);
}

Type* Typer::Visitor::TypeStringToNumber(Node* node) {
  return TypeUnaryOp(node, ToNumber);
}

Type* Typer::Visitor::TypePlainPrimitiveToNumber(Node* node) {
  return TypeUnaryOp(node, ToNumber);
}

Type* Typer::Visitor::TypePlainPrimitiveToWord32(Node* node) {
  return Type::Integral32();
}

Type* Typer::Visitor::TypePlainPrimitiveToFloat64(Node* node) {
  return Type::Number();
}

// static
Type* Typer::Visitor::ReferenceEqualTyper(Type* lhs, Type* rhs, Typer* t) {
  if (lhs->IsHeapConstant() && rhs->Is(lhs)) {
    return t->singleton_true_;
  }
  return Type::Boolean();
}


Type* Typer::Visitor::TypeReferenceEqual(Node* node) {
  return TypeBinaryOp(node, ReferenceEqualTyper);
}

// static
Type* Typer::Visitor::SameValueTyper(Type* lhs, Type* rhs, Typer* t) {
  return t->operation_typer()->SameValue(lhs, rhs);
}

Type* Typer::Visitor::TypeSameValue(Node* node) {
  return TypeBinaryOp(node, SameValueTyper);
}

Type* Typer::Visitor::TypeStringEqual(Node* node) { return Type::Boolean(); }

Type* Typer::Visitor::TypeStringLessThan(Node* node) { return Type::Boolean(); }

Type* Typer::Visitor::TypeStringLessThanOrEqual(Node* node) {
  return Type::Boolean();
}

Type* Typer::Visitor::StringFromCharCodeTyper(Type* type, Typer* t) {
  return Type::String();
}

Type* Typer::Visitor::StringFromCodePointTyper(Type* type, Typer* t) {
  return Type::String();
}

Type* Typer::Visitor::TypeStringCharAt(Node* node) { return Type::String(); }

Type* Typer::Visitor::TypeStringToLowerCaseIntl(Node* node) { UNREACHABLE(); }

Type* Typer::Visitor::TypeStringToUpperCaseIntl(Node* node) { UNREACHABLE(); }

Type* Typer::Visitor::TypeStringCharCodeAt(Node* node) {
  return typer_->cache_.kUint16;
}

Type* Typer::Visitor::TypeSeqStringCharCodeAt(Node* node) {
  return typer_->cache_.kUint16;
}

Type* Typer::Visitor::TypeStringCodePointAt(Node* node) {
  return Type::Range(0.0, String::kMaxCodePoint, zone());
}

Type* Typer::Visitor::TypeSeqStringCodePointAt(Node* node) {
  return Type::Range(0.0, String::kMaxCodePoint, zone());
}

Type* Typer::Visitor::TypeStringFromCharCode(Node* node) {
  return TypeUnaryOp(node, StringFromCharCodeTyper);
}

Type* Typer::Visitor::TypeStringFromCodePoint(Node* node) {
  return TypeUnaryOp(node, StringFromCodePointTyper);
}

Type* Typer::Visitor::TypeStringIndexOf(Node* node) {
  return Type::Range(-1.0, String::kMaxLength, zone());
}

Type* Typer::Visitor::TypeStringLength(Node* node) {
  return typer_->cache_.kStringLengthType;
}

Type* Typer::Visitor::TypeMaskIndexWithBound(Node* node) {
  return Type::Union(Operand(node, 0), typer_->cache_.kSingletonZero, zone());
}

Type* Typer::Visitor::TypeCheckBounds(Node* node) {
  Type* index = Operand(node, 0);
  Type* length = Operand(node, 1);
  DCHECK(length->Is(Type::Unsigned31()));
  if (index->Maybe(Type::MinusZero())) {
    index = Type::Union(index, typer_->cache_.kSingletonZero, zone());
  }
  index = Type::Intersect(index, Type::Integral32(), zone());
  if (index->IsNone() || length->IsNone()) return Type::None();
  double min = std::max(index->Min(), 0.0);
  double max = std::min(index->Max(), length->Max() - 1);
  if (max < min) return Type::None();
  return Type::Range(min, max, zone());
}

Type* Typer::Visitor::TypeCheckHeapObject(Node* node) {
  Type* type = Operand(node, 0);
  return type;
}

Type* Typer::Visitor::TypeCheckIf(Node* node) {
  UNREACHABLE();
}

Type* Typer::Visitor::TypeCheckInternalizedString(Node* node) {
  Type* arg = Operand(node, 0);
  return Type::Intersect(arg, Type::InternalizedString(), zone());
}

Type* Typer::Visitor::TypeCheckMaps(Node* node) {
  UNREACHABLE();
}

Type* Typer::Visitor::TypeCompareMaps(Node* node) { return Type::Boolean(); }

Type* Typer::Visitor::TypeCheckNumber(Node* node) {
  return typer_->operation_typer_.CheckNumber(Operand(node, 0));
}

Type* Typer::Visitor::TypeCheckReceiver(Node* node) {
  Type* arg = Operand(node, 0);
  return Type::Intersect(arg, Type::Receiver(), zone());
}

Type* Typer::Visitor::TypeCheckSmi(Node* node) {
  Type* arg = Operand(node, 0);
  return Type::Intersect(arg, Type::SignedSmall(), zone());
}

Type* Typer::Visitor::TypeCheckString(Node* node) {
  Type* arg = Operand(node, 0);
  return Type::Intersect(arg, Type::String(), zone());
}

Type* Typer::Visitor::TypeCheckSeqString(Node* node) {
  Type* arg = Operand(node, 0);
  return Type::Intersect(arg, Type::SeqString(), zone());
}

Type* Typer::Visitor::TypeCheckSymbol(Node* node) {
  Type* arg = Operand(node, 0);
  return Type::Intersect(arg, Type::Symbol(), zone());
}

Type* Typer::Visitor::TypeCheckFloat64Hole(Node* node) {
  return typer_->operation_typer_.CheckFloat64Hole(Operand(node, 0));
}

Type* Typer::Visitor::TypeCheckNotTaggedHole(Node* node) {
  Type* type = Operand(node, 0);
  type = Type::Intersect(type, Type::NonInternal(), zone());
  return type;
}

Type* Typer::Visitor::TypeConvertReceiver(Node* node) {
  Type* arg = Operand(node, 0);
  return typer_->operation_typer_.ConvertReceiver(arg);
}

Type* Typer::Visitor::TypeConvertTaggedHoleToUndefined(Node* node) {
  Type* type = Operand(node, 0);
  return typer_->operation_typer()->ConvertTaggedHoleToUndefined(type);
}

Type* Typer::Visitor::TypeCheckEqualsInternalizedString(Node* node) {
  UNREACHABLE();
}

Type* Typer::Visitor::TypeCheckEqualsSymbol(Node* node) { UNREACHABLE(); }

Type* Typer::Visitor::TypeAllocate(Node* node) {
  return AllocateTypeOf(node->op());
}

Type* Typer::Visitor::TypeAllocateRaw(Node* node) { UNREACHABLE(); }

Type* Typer::Visitor::TypeLoadFieldByIndex(Node* node) {
  return Type::NonInternal();
}

Type* Typer::Visitor::TypeLoadField(Node* node) {
  return FieldAccessOf(node->op()).type;
}

Type* Typer::Visitor::TypeLoadElement(Node* node) {
  return ElementAccessOf(node->op()).type;
}

Type* Typer::Visitor::TypeLoadTypedElement(Node* node) {
  switch (ExternalArrayTypeOf(node->op())) {
#define TYPED_ARRAY_CASE(ElemType, type, TYPE, ctype, size) \
  case kExternal##ElemType##Array:                          \
    return typer_->cache_.k##ElemType;
    TYPED_ARRAYS(TYPED_ARRAY_CASE)
#undef TYPED_ARRAY_CASE
  }
  UNREACHABLE();
}

Type* Typer::Visitor::TypeStoreField(Node* node) {
  UNREACHABLE();
}

Type* Typer::Visitor::TypeStoreElement(Node* node) {
  UNREACHABLE();
}

Type* Typer::Visitor::TypeTransitionAndStoreElement(Node* node) {
  UNREACHABLE();
}

Type* Typer::Visitor::TypeTransitionAndStoreNumberElement(Node* node) {
  UNREACHABLE();
}

Type* Typer::Visitor::TypeTransitionAndStoreNonNumberElement(Node* node) {
  UNREACHABLE();
}

Type* Typer::Visitor::TypeStoreSignedSmallElement(Node* node) { UNREACHABLE(); }

Type* Typer::Visitor::TypeStoreTypedElement(Node* node) {
  UNREACHABLE();
}

Type* Typer::Visitor::TypeObjectIsArrayBufferView(Node* node) {
  return TypeUnaryOp(node, ObjectIsArrayBufferView);
}

Type* Typer::Visitor::TypeObjectIsBigInt(Node* node) {
  return TypeUnaryOp(node, ObjectIsBigInt);
}

Type* Typer::Visitor::TypeObjectIsCallable(Node* node) {
  return TypeUnaryOp(node, ObjectIsCallable);
}

Type* Typer::Visitor::TypeObjectIsConstructor(Node* node) {
  return TypeUnaryOp(node, ObjectIsConstructor);
}

Type* Typer::Visitor::TypeObjectIsDetectableCallable(Node* node) {
  return TypeUnaryOp(node, ObjectIsDetectableCallable);
}

Type* Typer::Visitor::TypeObjectIsMinusZero(Node* node) {
  return TypeUnaryOp(node, ObjectIsMinusZero);
}

Type* Typer::Visitor::TypeNumberIsFloat64Hole(Node* node) {
  return Type::Boolean();
}

Type* Typer::Visitor::TypeObjectIsNaN(Node* node) {
  return TypeUnaryOp(node, ObjectIsNaN);
}

Type* Typer::Visitor::TypeObjectIsNonCallable(Node* node) {
  return TypeUnaryOp(node, ObjectIsNonCallable);
}

Type* Typer::Visitor::TypeObjectIsNumber(Node* node) {
  return TypeUnaryOp(node, ObjectIsNumber);
}


Type* Typer::Visitor::TypeObjectIsReceiver(Node* node) {
  return TypeUnaryOp(node, ObjectIsReceiver);
}


Type* Typer::Visitor::TypeObjectIsSmi(Node* node) {
  return TypeUnaryOp(node, ObjectIsSmi);
}

Type* Typer::Visitor::TypeObjectIsString(Node* node) {
  return TypeUnaryOp(node, ObjectIsString);
}

Type* Typer::Visitor::TypeObjectIsSymbol(Node* node) {
  return TypeUnaryOp(node, ObjectIsSymbol);
}

Type* Typer::Visitor::TypeObjectIsUndetectable(Node* node) {
  return TypeUnaryOp(node, ObjectIsUndetectable);
}

Type* Typer::Visitor::TypeArgumentsLength(Node* node) {
  return TypeCache::Get().kArgumentsLengthType;
}

Type* Typer::Visitor::TypeArgumentsFrame(Node* node) {
  return Type::ExternalPointer();
}

Type* Typer::Visitor::TypeNewDoubleElements(Node* node) {
  return Type::OtherInternal();
}

Type* Typer::Visitor::TypeNewSmiOrObjectElements(Node* node) {
  return Type::OtherInternal();
}

Type* Typer::Visitor::TypeNewArgumentsElements(Node* node) {
  return Type::OtherInternal();
}

Type* Typer::Visitor::TypeNewConsString(Node* node) {
  return Type::OtherNonSeqString();
}

Type* Typer::Visitor::TypeArrayBufferWasNeutered(Node* node) {
  return Type::Boolean();
}

Type* Typer::Visitor::TypeFindOrderedHashMapEntry(Node* node) {
  return Type::Range(-1.0, FixedArray::kMaxLength, zone());
}

Type* Typer::Visitor::TypeFindOrderedHashMapEntryForInt32Key(Node* node) {
  return Type::Range(-1.0, FixedArray::kMaxLength, zone());
}

Type* Typer::Visitor::TypeRuntimeAbort(Node* node) { UNREACHABLE(); }

// Heap constants.

Type* Typer::Visitor::TypeConstant(Handle<Object> value) {
  if (Type::IsInteger(*value)) {
    return Type::Range(value->Number(), value->Number(), zone());
  }
  return Type::NewConstant(value, zone());
}

}  // namespace compiler
}  // namespace internal
}  // namespace v8