src/jit/TypePolicy.cpp

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 * vim: set ts=8 sts=4 et sw=4 tw=99:
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "jit/TypePolicy.h"

#include "jit/Lowering.h"
#include "jit/MIR.h"
#include "jit/MIRGraph.h"

#include "jit/shared/Lowering-shared-inl.h"

using namespace js;
using namespace js::jit;

using JS::DoubleNaNValue;

static void EnsureOperandNotFloat32(TempAllocator& alloc, MInstruction* def,
                                    unsigned op) {
  MDefinition* in = def->getOperand(op);
  if (in->type() == MIRType::Float32) {
    MToDouble* replace = MToDouble::New(alloc, in);
    def->block()->insertBefore(def, replace);
    if (def->isRecoveredOnBailout()) replace->setRecoveredOnBailout();
    def->replaceOperand(op, replace);
  }
}

MDefinition* js::jit::AlwaysBoxAt(TempAllocator& alloc, MInstruction* at,
                                  MDefinition* operand) {
  MDefinition* boxedOperand = operand;
  // Replace Float32 by double
  if (operand->type() == MIRType::Float32) {
    MInstruction* replace = MToDouble::New(alloc, operand);
    at->block()->insertBefore(at, replace);
    boxedOperand = replace;
  }
  MBox* box = MBox::New(alloc, boxedOperand);
  at->block()->insertBefore(at, box);
  return box;
}

static MDefinition* BoxAt(TempAllocator& alloc, MInstruction* at,
                          MDefinition* operand) {
  if (operand->isUnbox()) return operand->toUnbox()->input();
  return AlwaysBoxAt(alloc, at, operand);
}

bool BoxInputsPolicy::staticAdjustInputs(TempAllocator& alloc,
                                         MInstruction* ins) {
  for (size_t i = 0, e = ins->numOperands(); i < e; i++) {
    MDefinition* in = ins->getOperand(i);
    if (in->type() == MIRType::Value) continue;
    ins->replaceOperand(i, BoxAt(alloc, ins, in));
  }
  return true;
}

bool ArithPolicy::adjustInputs(TempAllocator& alloc, MInstruction* ins) {
  MIRType specialization = ins->typePolicySpecialization();
  if (specialization == MIRType::None)
    return BoxInputsPolicy::staticAdjustInputs(alloc, ins);

  MOZ_ASSERT(ins->type() == MIRType::Double || ins->type() == MIRType::Int32 ||
             ins->type() == MIRType::Float32);

  for (size_t i = 0, e = ins->numOperands(); i < e; i++) {
    MDefinition* in = ins->getOperand(i);
    if (in->type() == ins->type()) continue;

    MInstruction* replace;

    if (ins->type() == MIRType::Double)
      replace = MToDouble::New(alloc, in);
    else if (ins->type() == MIRType::Float32)
      replace = MToFloat32::New(alloc, in);
    else
      replace = MToNumberInt32::New(alloc, in);

    ins->block()->insertBefore(ins, replace);
    ins->replaceOperand(i, replace);

    if (!replace->typePolicy()->adjustInputs(alloc, replace)) return false;
  }

  return true;
}

bool AllDoublePolicy::staticAdjustInputs(TempAllocator& alloc,
                                         MInstruction* ins) {
  for (size_t i = 0, e = ins->numOperands(); i < e; i++) {
    MDefinition* in = ins->getOperand(i);
    if (in->type() == MIRType::Double) continue;

    if (!alloc.ensureBallast()) return false;
    MInstruction* replace = MToDouble::New(alloc, in);

    ins->block()->insertBefore(ins, replace);
    ins->replaceOperand(i, replace);

    if (!replace->typePolicy()->adjustInputs(alloc, replace)) return false;
  }

  return true;
}

bool ComparePolicy::adjustInputs(TempAllocator& alloc, MInstruction* def) {
  MOZ_ASSERT(def->isCompare());
  MCompare* compare = def->toCompare();

  // Convert Float32 operands to doubles
  for (size_t i = 0; i < 2; i++) {
    MDefinition* in = def->getOperand(i);
    if (in->type() == MIRType::Float32) {
      MInstruction* replace = MToDouble::New(alloc, in);
      def->block()->insertBefore(def, replace);
      def->replaceOperand(i, replace);
    }
  }

  // Box inputs to get value
  if (compare->compareType() == MCompare::Compare_Unknown ||
      compare->compareType() == MCompare::Compare_Bitwise) {
    return BoxInputsPolicy::staticAdjustInputs(alloc, def);
  }

  // Compare_Boolean specialization is done for "Anything === Bool"
  // If the LHS is boolean, we set the specialization to Compare_Int32.
  // This matches other comparisons of the form bool === bool and
  // generated code of Compare_Int32 is more efficient.
  if (compare->compareType() == MCompare::Compare_Boolean &&
      def->getOperand(0)->type() == MIRType::Boolean) {
    compare->setCompareType(MCompare::Compare_Int32MaybeCoerceBoth);
  }

  // Compare_Boolean specialization is done for "Anything === Bool"
  // As of previous line Anything can't be Boolean
  if (compare->compareType() == MCompare::Compare_Boolean) {
    // Unbox rhs that is definitely Boolean
    MDefinition* rhs = def->getOperand(1);
    if (rhs->type() != MIRType::Boolean) {
      MInstruction* unbox =
          MUnbox::New(alloc, rhs, MIRType::Boolean, MUnbox::Infallible);
      def->block()->insertBefore(def, unbox);
      def->replaceOperand(1, unbox);
      if (!unbox->typePolicy()->adjustInputs(alloc, unbox)) return false;
    }

    MOZ_ASSERT(def->getOperand(0)->type() != MIRType::Boolean);
    MOZ_ASSERT(def->getOperand(1)->type() == MIRType::Boolean);
    return true;
  }

  // Compare_StrictString specialization is done for "Anything === String"
  // If the LHS is string, we set the specialization to Compare_String.
  if (compare->compareType() == MCompare::Compare_StrictString &&
      def->getOperand(0)->type() == MIRType::String) {
    compare->setCompareType(MCompare::Compare_String);
  }

  // Compare_StrictString specialization is done for "Anything === String"
  // As of previous line Anything can't be String
  if (compare->compareType() == MCompare::Compare_StrictString) {
    // Unbox rhs that is definitely String
    MDefinition* rhs = def->getOperand(1);
    if (rhs->type() != MIRType::String) {
      MInstruction* unbox =
          MUnbox::New(alloc, rhs, MIRType::String, MUnbox::Infallible);
      def->block()->insertBefore(def, unbox);
      def->replaceOperand(1, unbox);
      if (!unbox->typePolicy()->adjustInputs(alloc, unbox)) return false;
    }

    MOZ_ASSERT(def->getOperand(0)->type() != MIRType::String);
    MOZ_ASSERT(def->getOperand(1)->type() == MIRType::String);
    return true;
  }

  if (compare->compareType() == MCompare::Compare_Undefined ||
      compare->compareType() == MCompare::Compare_Null) {
    // Nothing to do for undefined and null, lowering handles all types.
    return true;
  }

  // Convert all inputs to the right input type
  MIRType type = compare->inputType();
  MOZ_ASSERT(type == MIRType::Int32 || type == MIRType::Double ||
             type == MIRType::Float32 || type == MIRType::Object ||
             type == MIRType::String || type == MIRType::Symbol);
  for (size_t i = 0; i < 2; i++) {
    MDefinition* in = def->getOperand(i);
    if (in->type() == type) continue;

    MInstruction* replace;

    switch (type) {
      case MIRType::Double: {
        MToFPInstruction::ConversionKind convert =
            MToFPInstruction::NumbersOnly;
        if (compare->compareType() == MCompare::Compare_DoubleMaybeCoerceLHS &&
            i == 0)
          convert = MToFPInstruction::NonNullNonStringPrimitives;
        else if (compare->compareType() ==
                     MCompare::Compare_DoubleMaybeCoerceRHS &&
                 i == 1)
          convert = MToFPInstruction::NonNullNonStringPrimitives;
        replace = MToDouble::New(alloc, in, convert);
        break;
      }
      case MIRType::Float32: {
        MToFPInstruction::ConversionKind convert =
            MToFPInstruction::NumbersOnly;
        if (compare->compareType() == MCompare::Compare_DoubleMaybeCoerceLHS &&
            i == 0)
          convert = MToFPInstruction::NonNullNonStringPrimitives;
        else if (compare->compareType() ==
                     MCompare::Compare_DoubleMaybeCoerceRHS &&
                 i == 1)
          convert = MToFPInstruction::NonNullNonStringPrimitives;
        replace = MToFloat32::New(alloc, in, convert);
        break;
      }
      case MIRType::Int32: {
        IntConversionInputKind convert = IntConversionInputKind::NumbersOnly;
        if (compare->compareType() == MCompare::Compare_Int32MaybeCoerceBoth ||
            (compare->compareType() == MCompare::Compare_Int32MaybeCoerceLHS &&
             i == 0) ||
            (compare->compareType() == MCompare::Compare_Int32MaybeCoerceRHS &&
             i == 1)) {
          convert = IntConversionInputKind::NumbersOrBoolsOnly;
        }
        replace = MToNumberInt32::New(alloc, in, convert);
        break;
      }
      case MIRType::Object:
        replace = MUnbox::New(alloc, in, MIRType::Object, MUnbox::Infallible);
        break;
      case MIRType::String:
        replace = MUnbox::New(alloc, in, MIRType::String, MUnbox::Infallible);
        break;
      case MIRType::Symbol:
        replace = MUnbox::New(alloc, in, MIRType::Symbol, MUnbox::Infallible);
        break;
      default:
        MOZ_CRASH("Unknown compare specialization");
    }

    def->block()->insertBefore(def, replace);
    def->replaceOperand(i, replace);

    if (!replace->typePolicy()->adjustInputs(alloc, replace)) return false;
  }

  return true;
}

bool SameValuePolicy::adjustInputs(TempAllocator& alloc, MInstruction* def) {
  MOZ_ASSERT(def->isSameValue());
  MSameValue* sameValue = def->toSameValue();
  MIRType lhsType = sameValue->lhs()->type();
  MIRType rhsType = sameValue->rhs()->type();

  // If both operands are numbers, convert them to doubles.
  if (IsNumberType(lhsType) && IsNumberType(rhsType))
    return AllDoublePolicy::staticAdjustInputs(alloc, def);

  // SameValue(Anything, Double) is specialized, so convert the rhs if it's
  // not already a double.
  if (lhsType == MIRType::Value && IsNumberType(rhsType)) {
    if (rhsType != MIRType::Double) {
      MInstruction* replace = MToDouble::New(alloc, sameValue->rhs());
      def->block()->insertBefore(def, replace);
      def->replaceOperand(1, replace);

      if (!replace->typePolicy()->adjustInputs(alloc, replace)) return false;
    }

    return true;
  }

  // Otherwise box both operands.
  return BoxInputsPolicy::staticAdjustInputs(alloc, def);
}

bool TypeBarrierPolicy::adjustInputs(TempAllocator& alloc, MInstruction* def) {
  MTypeBarrier* ins = def->toTypeBarrier();
  MIRType inputType = ins->getOperand(0)->type();
  MIRType outputType = ins->type();

  // Input and output type are already in accordance.
  if (inputType == outputType) return true;

  // Output is a value, currently box the input.
  if (outputType == MIRType::Value) {
    // XXX: Possible optimization: decrease resultTypeSet to only include
    // the inputType. This will remove the need for boxing.
    MOZ_ASSERT(inputType != MIRType::Value);
    ins->replaceOperand(0, BoxAt(alloc, ins, ins->getOperand(0)));
    return true;
  }

  // Box input if needed.
  if (inputType != MIRType::Value) {
    MOZ_ASSERT(ins->alwaysBails());
    ins->replaceOperand(0, BoxAt(alloc, ins, ins->getOperand(0)));
  }

  // We can't unbox a value to null/undefined/lazyargs. So keep output
  // also a value.
  // Note: Using setResultType shouldn't be done in TypePolicies,
  //       Here it is fine, since the type barrier has no uses.
  if (IsNullOrUndefined(outputType) ||
      outputType == MIRType::MagicOptimizedArguments) {
    MOZ_ASSERT(!ins->hasDefUses());
    ins->setResultType(MIRType::Value);
    return true;
  }

  // Unbox / propagate the right type.
  MUnbox::Mode mode = MUnbox::TypeBarrier;
  MInstruction* replace =
      MUnbox::New(alloc, ins->getOperand(0), ins->type(), mode);
  if (!ins->isMovable()) replace->setNotMovable();

  ins->block()->insertBefore(ins, replace);
  ins->replaceOperand(0, replace);
  if (!replace->typePolicy()->adjustInputs(alloc, replace)) return false;

  // The TypeBarrier is equivalent to removing branches with unexpected
  // types.  The unexpected types would have changed Range Analysis
  // predictions.  As such, we need to prevent destructive optimizations.
  ins->block()->flagOperandsOfPrunedBranches(replace);

  return true;
}

bool TestPolicy::adjustInputs(TempAllocator& alloc, MInstruction* ins) {
  MDefinition* op = ins->getOperand(0);
  switch (op->type()) {
    case MIRType::Value:
    case MIRType::Null:
    case MIRType::Undefined:
    case MIRType::Boolean:
    case MIRType::Int32:
    case MIRType::Double:
    case MIRType::Float32:
    case MIRType::Symbol:
    case MIRType::Object:
      break;

    case MIRType::String: {
      MStringLength* length = MStringLength::New(alloc, op);
      ins->block()->insertBefore(ins, length);
      ins->replaceOperand(0, length);
      break;
    }

    default:
      ins->replaceOperand(0, BoxAt(alloc, ins, op));
      break;
  }
  return true;
}

bool BitwisePolicy::adjustInputs(TempAllocator& alloc, MInstruction* ins) {
  MIRType specialization = ins->typePolicySpecialization();
  if (specialization == MIRType::None)
    return BoxInputsPolicy::staticAdjustInputs(alloc, ins);

  MOZ_ASSERT(ins->type() == specialization);
  MOZ_ASSERT(specialization == MIRType::Int32 ||
             specialization == MIRType::Double);

  // This policy works for both unary and binary bitwise operations.
  for (size_t i = 0, e = ins->numOperands(); i < e; i++) {
    MDefinition* in = ins->getOperand(i);
    if (in->type() == MIRType::Int32) continue;

    MInstruction* replace = MTruncateToInt32::New(alloc, in);
    ins->block()->insertBefore(ins, replace);
    ins->replaceOperand(i, replace);

    if (!replace->typePolicy()->adjustInputs(alloc, replace)) return false;
  }

  return true;
}

bool PowPolicy::adjustInputs(TempAllocator& alloc, MInstruction* ins) {
  MIRType specialization = ins->typePolicySpecialization();
  MOZ_ASSERT(specialization == MIRType::Int32 ||
             specialization == MIRType::Double ||
             specialization == MIRType::None);

  // Inputs will be boxed if either is non-numeric.
  if (specialization == MIRType::None)
    return BoxInputsPolicy::staticAdjustInputs(alloc, ins);

  // Otherwise, input must be a double.
  if (!DoublePolicy<0>::staticAdjustInputs(alloc, ins)) return false;

  // Power may be an int32 or a double. Integers receive a faster path.
  if (specialization == MIRType::Double)
    return DoublePolicy<1>::staticAdjustInputs(alloc, ins);
  return UnboxedInt32Policy<1>::staticAdjustInputs(alloc, ins);
}

template <unsigned Op>
bool StringPolicy<Op>::staticAdjustInputs(TempAllocator& alloc,
                                          MInstruction* ins) {
  MDefinition* in = ins->getOperand(Op);
  if (in->type() == MIRType::String) return true;

  MUnbox* replace = MUnbox::New(alloc, in, MIRType::String, MUnbox::Fallible);
  ins->block()->insertBefore(ins, replace);
  ins->replaceOperand(Op, replace);

  return replace->typePolicy()->adjustInputs(alloc, replace);
}

template bool StringPolicy<0>::staticAdjustInputs(TempAllocator& alloc,
                                                  MInstruction* ins);
template bool StringPolicy<1>::staticAdjustInputs(TempAllocator& alloc,
                                                  MInstruction* ins);
template bool StringPolicy<2>::staticAdjustInputs(TempAllocator& alloc,
                                                  MInstruction* ins);

template <unsigned Op>
bool ConvertToStringPolicy<Op>::staticAdjustInputs(TempAllocator& alloc,
                                                   MInstruction* ins) {
  MDefinition* in = ins->getOperand(Op);
  if (in->type() == MIRType::String) return true;

  MToString* replace = MToString::New(alloc, in);
  ins->block()->insertBefore(ins, replace);
  ins->replaceOperand(Op, replace);

  if (!ToStringPolicy::staticAdjustInputs(alloc, replace)) return false;

  return true;
}

template bool ConvertToStringPolicy<0>::staticAdjustInputs(TempAllocator& alloc,
                                                           MInstruction* ins);
template bool ConvertToStringPolicy<1>::staticAdjustInputs(TempAllocator& alloc,
                                                           MInstruction* ins);
template bool ConvertToStringPolicy<2>::staticAdjustInputs(TempAllocator& alloc,
                                                           MInstruction* ins);

template <unsigned Op>
bool BooleanPolicy<Op>::staticAdjustInputs(TempAllocator& alloc,
                                           MInstruction* def) {
  MDefinition* in = def->getOperand(Op);
  if (in->type() == MIRType::Boolean) return true;

  MUnbox* replace = MUnbox::New(alloc, in, MIRType::Boolean, MUnbox::Fallible);
  def->block()->insertBefore(def, replace);
  def->replaceOperand(Op, replace);

  return replace->typePolicy()->adjustInputs(alloc, replace);
}

template bool BooleanPolicy<3>::staticAdjustInputs(TempAllocator& alloc,
                                                   MInstruction* def);

template <unsigned Op>
bool UnboxedInt32Policy<Op>::staticAdjustInputs(TempAllocator& alloc,
                                                MInstruction* def) {
  MDefinition* in = def->getOperand(Op);
  if (in->type() == MIRType::Int32) return true;

  MUnbox* replace = MUnbox::New(alloc, in, MIRType::Int32, MUnbox::Fallible);
  def->block()->insertBefore(def, replace);
  def->replaceOperand(Op, replace);

  return replace->typePolicy()->adjustInputs(alloc, replace);
}

template bool UnboxedInt32Policy<0>::staticAdjustInputs(TempAllocator& alloc,
                                                        MInstruction* def);
template bool UnboxedInt32Policy<1>::staticAdjustInputs(TempAllocator& alloc,
                                                        MInstruction* def);
template bool UnboxedInt32Policy<2>::staticAdjustInputs(TempAllocator& alloc,
                                                        MInstruction* def);
template bool UnboxedInt32Policy<3>::staticAdjustInputs(TempAllocator& alloc,
                                                        MInstruction* def);

template <unsigned Op>
bool ConvertToInt32Policy<Op>::staticAdjustInputs(TempAllocator& alloc,
                                                  MInstruction* def) {
  MDefinition* in = def->getOperand(Op);
  if (in->type() == MIRType::Int32) return true;

  auto* replace = MToNumberInt32::New(alloc, in);
  def->block()->insertBefore(def, replace);
  def->replaceOperand(Op, replace);

  return replace->typePolicy()->adjustInputs(alloc, replace);
}

template bool ConvertToInt32Policy<0>::staticAdjustInputs(TempAllocator& alloc,
                                                          MInstruction* def);

template <unsigned Op>
bool TruncateToInt32Policy<Op>::staticAdjustInputs(TempAllocator& alloc,
                                                   MInstruction* def) {
  MDefinition* in = def->getOperand(Op);
  if (in->type() == MIRType::Int32) return true;

  MTruncateToInt32* replace = MTruncateToInt32::New(alloc, in);
  def->block()->insertBefore(def, replace);
  def->replaceOperand(Op, replace);

  return replace->typePolicy()->adjustInputs(alloc, replace);
}

template bool TruncateToInt32Policy<2>::staticAdjustInputs(TempAllocator& alloc,
                                                           MInstruction* def);
template bool TruncateToInt32Policy<3>::staticAdjustInputs(TempAllocator& alloc,
                                                           MInstruction* def);

template <unsigned Op>
bool DoublePolicy<Op>::staticAdjustInputs(TempAllocator& alloc,
                                          MInstruction* def) {
  MDefinition* in = def->getOperand(Op);
  if (in->type() == MIRType::Double || in->type() == MIRType::SinCosDouble)
    return true;

  MToDouble* replace = MToDouble::New(alloc, in);
  def->block()->insertBefore(def, replace);
  def->replaceOperand(Op, replace);

  return replace->typePolicy()->adjustInputs(alloc, replace);
}

template bool DoublePolicy<0>::staticAdjustInputs(TempAllocator& alloc,
                                                  MInstruction* def);
template bool DoublePolicy<1>::staticAdjustInputs(TempAllocator& alloc,
                                                  MInstruction* def);

template <unsigned Op>
bool Float32Policy<Op>::staticAdjustInputs(TempAllocator& alloc,
                                           MInstruction* def) {
  MDefinition* in = def->getOperand(Op);
  if (in->type() == MIRType::Float32) return true;

  MToFloat32* replace = MToFloat32::New(alloc, in);
  def->block()->insertBefore(def, replace);
  def->replaceOperand(Op, replace);

  return replace->typePolicy()->adjustInputs(alloc, replace);
}

template bool Float32Policy<0>::staticAdjustInputs(TempAllocator& alloc,
                                                   MInstruction* def);
template bool Float32Policy<1>::staticAdjustInputs(TempAllocator& alloc,
                                                   MInstruction* def);
template bool Float32Policy<2>::staticAdjustInputs(TempAllocator& alloc,
                                                   MInstruction* def);

template <unsigned Op>
bool FloatingPointPolicy<Op>::adjustInputs(TempAllocator& alloc,
                                           MInstruction* def) {
  MIRType policyType = def->typePolicySpecialization();
  if (policyType == MIRType::Double)
    return DoublePolicy<Op>::staticAdjustInputs(alloc, def);
  return Float32Policy<Op>::staticAdjustInputs(alloc, def);
}

template bool FloatingPointPolicy<0>::adjustInputs(TempAllocator& alloc,
                                                   MInstruction* def);

template <unsigned Op>
bool NoFloatPolicy<Op>::staticAdjustInputs(TempAllocator& alloc,
                                           MInstruction* def) {
  EnsureOperandNotFloat32(alloc, def, Op);
  return true;
}

template bool NoFloatPolicy<0>::staticAdjustInputs(TempAllocator& alloc,
                                                   MInstruction* def);
template bool NoFloatPolicy<1>::staticAdjustInputs(TempAllocator& alloc,
                                                   MInstruction* def);
template bool NoFloatPolicy<2>::staticAdjustInputs(TempAllocator& alloc,
                                                   MInstruction* def);
template bool NoFloatPolicy<3>::staticAdjustInputs(TempAllocator& alloc,
                                                   MInstruction* def);

template <unsigned FirstOp>
bool NoFloatPolicyAfter<FirstOp>::adjustInputs(TempAllocator& alloc,
                                               MInstruction* def) {
  for (size_t op = FirstOp, e = def->numOperands(); op < e; op++)
    EnsureOperandNotFloat32(alloc, def, op);
  return true;
}

template bool NoFloatPolicyAfter<0>::adjustInputs(TempAllocator& alloc,
                                                  MInstruction* def);
template bool NoFloatPolicyAfter<1>::adjustInputs(TempAllocator& alloc,
                                                  MInstruction* def);
template bool NoFloatPolicyAfter<2>::adjustInputs(TempAllocator& alloc,
                                                  MInstruction* def);

template <unsigned Op>
bool SimdScalarPolicy<Op>::staticAdjustInputs(TempAllocator& alloc,
                                              MInstruction* ins) {
  MOZ_ASSERT(IsSimdType(ins->type()));
  MIRType laneType = SimdTypeToLaneType(ins->type());

  MDefinition* in = ins->getOperand(Op);

  // A vector with boolean lanes requires Int32 inputs that have already been
  // converted to 0/-1.
  // We can't insert a MIRType::Boolean lane directly - it requires conversion.
  if (laneType == MIRType::Boolean) {
    MOZ_ASSERT(in->type() == MIRType::Int32,
               "Boolean SIMD vector requires Int32 lanes.");
    return true;
  }

  if (in->type() == laneType) return true;

  MInstruction* replace;
  if (laneType == MIRType::Int32) {
    replace = MTruncateToInt32::New(alloc, in);
  } else {
    MOZ_ASSERT(laneType == MIRType::Float32);
    replace = MToFloat32::New(alloc, in);
  }

  ins->block()->insertBefore(ins, replace);
  ins->replaceOperand(Op, replace);

  return replace->typePolicy()->adjustInputs(alloc, replace);
}

template bool SimdScalarPolicy<0>::staticAdjustInputs(TempAllocator& alloc,
                                                      MInstruction* def);
template bool SimdScalarPolicy<1>::staticAdjustInputs(TempAllocator& alloc,
                                                      MInstruction* def);
template bool SimdScalarPolicy<2>::staticAdjustInputs(TempAllocator& alloc,
                                                      MInstruction* def);
template bool SimdScalarPolicy<3>::staticAdjustInputs(TempAllocator& alloc,
                                                      MInstruction* def);

template <unsigned Op>
bool BoxPolicy<Op>::staticAdjustInputs(TempAllocator& alloc,
                                       MInstruction* ins) {
  MDefinition* in = ins->getOperand(Op);
  if (in->type() == MIRType::Value) return true;

  ins->replaceOperand(Op, BoxAt(alloc, ins, in));
  return true;
}

template bool BoxPolicy<0>::staticAdjustInputs(TempAllocator& alloc,
                                               MInstruction* ins);
template bool BoxPolicy<1>::staticAdjustInputs(TempAllocator& alloc,
                                               MInstruction* ins);
template bool BoxPolicy<2>::staticAdjustInputs(TempAllocator& alloc,
                                               MInstruction* ins);

template <unsigned Op, MIRType Type>
bool BoxExceptPolicy<Op, Type>::staticAdjustInputs(TempAllocator& alloc,
                                                   MInstruction* ins) {
  MDefinition* in = ins->getOperand(Op);
  if (in->type() == Type) return true;
  return BoxPolicy<Op>::staticAdjustInputs(alloc, ins);
}

template bool BoxExceptPolicy<0, MIRType::Object>::staticAdjustInputs(
    TempAllocator& alloc, MInstruction* ins);

template <unsigned Op>
bool CacheIdPolicy<Op>::staticAdjustInputs(TempAllocator& alloc,
                                           MInstruction* ins) {
  MDefinition* in = ins->getOperand(Op);
  switch (in->type()) {
    case MIRType::Int32:
    case MIRType::String:
    case MIRType::Symbol:
      return true;
    default:
      return BoxPolicy<Op>::staticAdjustInputs(alloc, ins);
  }
}

template bool CacheIdPolicy<0>::staticAdjustInputs(TempAllocator& alloc,
                                                   MInstruction* ins);
template bool CacheIdPolicy<1>::staticAdjustInputs(TempAllocator& alloc,
                                                   MInstruction* ins);

bool ToDoublePolicy::staticAdjustInputs(TempAllocator& alloc,
                                        MInstruction* ins) {
  MOZ_ASSERT(ins->isToDouble() || ins->isToFloat32());

  MDefinition* in = ins->getOperand(0);
  MToFPInstruction::ConversionKind conversion;
  if (ins->isToDouble())
    conversion = ins->toToDouble()->conversion();
  else
    conversion = ins->toToFloat32()->conversion();

  switch (in->type()) {
    case MIRType::Int32:
    case MIRType::Float32:
    case MIRType::Double:
    case MIRType::Value:
      // No need for boxing for these types.
      return true;
    case MIRType::Null:
      // No need for boxing, when we will convert.
      if (conversion == MToFPInstruction::NonStringPrimitives) return true;
      break;
    case MIRType::Undefined:
    case MIRType::Boolean:
      // No need for boxing, when we will convert.
      if (conversion == MToFPInstruction::NonStringPrimitives) return true;
      if (conversion == MToFPInstruction::NonNullNonStringPrimitives)
        return true;
      break;
    case MIRType::Object:
    case MIRType::String:
    case MIRType::Symbol:
      // Objects might be effectful. Symbols give TypeError.
      break;
    default:
      break;
  }

  in = BoxAt(alloc, ins, in);
  ins->replaceOperand(0, in);
  return true;
}

bool ToInt32Policy::staticAdjustInputs(TempAllocator& alloc,
                                       MInstruction* ins) {
  MOZ_ASSERT(ins->isToNumberInt32() || ins->isTruncateToInt32());

  IntConversionInputKind conversion = IntConversionInputKind::Any;
  if (ins->isToNumberInt32()) conversion = ins->toToNumberInt32()->conversion();

  MDefinition* in = ins->getOperand(0);
  switch (in->type()) {
    case MIRType::Int32:
    case MIRType::Float32:
    case MIRType::Double:
    case MIRType::Value:
      // No need for boxing for these types.
      return true;
    case MIRType::Undefined:
      // No need for boxing when truncating.
      if (ins->isTruncateToInt32()) return true;
      break;
    case MIRType::Null:
      // No need for boxing, when we will convert.
      if (conversion == IntConversionInputKind::Any) return true;
      break;
    case MIRType::Boolean:
      // No need for boxing, when we will convert.
      if (conversion == IntConversionInputKind::Any) return true;
      if (conversion == IntConversionInputKind::NumbersOrBoolsOnly) return true;
      break;
    case MIRType::Object:
    case MIRType::String:
    case MIRType::Symbol:
      // Objects might be effectful. Symbols give TypeError.
      break;
    default:
      break;
  }

  in = BoxAt(alloc, ins, in);
  ins->replaceOperand(0, in);
  return true;
}

bool ToStringPolicy::staticAdjustInputs(TempAllocator& alloc,
                                        MInstruction* ins) {
  MOZ_ASSERT(ins->isToString());

  MIRType type = ins->getOperand(0)->type();
  if (type == MIRType::Object || type == MIRType::Symbol) {
    ins->replaceOperand(0, BoxAt(alloc, ins, ins->getOperand(0)));
    return true;
  }

  // TODO remove the following line once 966957 has landed
  EnsureOperandNotFloat32(alloc, ins, 0);

  return true;
}

template <unsigned Op>
bool ObjectPolicy<Op>::staticAdjustInputs(TempAllocator& alloc,
                                          MInstruction* ins) {
  MDefinition* in = ins->getOperand(Op);
  if (in->type() == MIRType::Object || in->type() == MIRType::Slots ||
      in->type() == MIRType::Elements) {
    return true;
  }

  MUnbox* replace = MUnbox::New(alloc, in, MIRType::Object, MUnbox::Fallible);
  ins->block()->insertBefore(ins, replace);
  ins->replaceOperand(Op, replace);

  return replace->typePolicy()->adjustInputs(alloc, replace);
}

template bool ObjectPolicy<0>::staticAdjustInputs(TempAllocator& alloc,
                                                  MInstruction* ins);
template bool ObjectPolicy<1>::staticAdjustInputs(TempAllocator& alloc,
                                                  MInstruction* ins);
template bool ObjectPolicy<2>::staticAdjustInputs(TempAllocator& alloc,
                                                  MInstruction* ins);
template bool ObjectPolicy<3>::staticAdjustInputs(TempAllocator& alloc,
                                                  MInstruction* ins);

template <unsigned Op>
bool SimdSameAsReturnedTypePolicy<Op>::staticAdjustInputs(TempAllocator& alloc,
                                                          MInstruction* ins) {
  MOZ_ASSERT(ins->type() == ins->getOperand(Op)->type());
  return true;
}

template bool SimdSameAsReturnedTypePolicy<0>::staticAdjustInputs(
    TempAllocator& alloc, MInstruction* ins);
template bool SimdSameAsReturnedTypePolicy<1>::staticAdjustInputs(
    TempAllocator& alloc, MInstruction* ins);

bool SimdAllPolicy::adjustInputs(TempAllocator& alloc, MInstruction* ins) {
  for (unsigned i = 0, e = ins->numOperands(); i < e; i++)
    MOZ_ASSERT(ins->getOperand(i)->type() == ins->typePolicySpecialization());
  return true;
}

template <unsigned Op>
bool SimdPolicy<Op>::adjustInputs(TempAllocator& alloc, MInstruction* ins) {
  MOZ_ASSERT(ins->typePolicySpecialization() == ins->getOperand(Op)->type());
  return true;
}

template bool SimdPolicy<0>::adjustInputs(TempAllocator& alloc,
                                          MInstruction* ins);

bool SimdShufflePolicy::adjustInputs(TempAllocator& alloc, MInstruction* ins) {
  MSimdGeneralShuffle* s = ins->toSimdGeneralShuffle();

  for (unsigned i = 0; i < s->numVectors(); i++)
    MOZ_ASSERT(ins->getOperand(i)->type() == ins->typePolicySpecialization());

  // Next inputs are the lanes, which need to be int32
  for (unsigned i = 0; i < s->numLanes(); i++) {
    MDefinition* in = ins->getOperand(s->numVectors() + i);
    if (in->type() == MIRType::Int32) continue;

    auto* replace =
        MToNumberInt32::New(alloc, in, IntConversionInputKind::NumbersOnly);
    ins->block()->insertBefore(ins, replace);
    ins->replaceOperand(s->numVectors() + i, replace);
    if (!replace->typePolicy()->adjustInputs(alloc, replace)) return false;
  }

  return true;
}

bool SimdSelectPolicy::adjustInputs(TempAllocator& alloc, MInstruction* ins) {
  // First input is the mask, which has to be a boolean.
  MOZ_ASSERT(IsBooleanSimdType(ins->getOperand(0)->type()));

  // Next inputs are the two vectors of a particular type.
  for (unsigned i = 1; i < 3; i++)
    MOZ_ASSERT(ins->getOperand(i)->type() == ins->typePolicySpecialization());

  return true;
}

bool CallPolicy::adjustInputs(TempAllocator& alloc, MInstruction* ins) {
  MCall* call = ins->toCall();

  MDefinition* func = call->getFunction();
  if (func->type() != MIRType::Object) {
    MInstruction* unbox =
        MUnbox::New(alloc, func, MIRType::Object, MUnbox::Fallible);
    call->block()->insertBefore(call, unbox);
    call->replaceFunction(unbox);

    if (!unbox->typePolicy()->adjustInputs(alloc, unbox)) return false;
  }

  for (uint32_t i = 0; i < call->numStackArgs(); i++) {
    if (!alloc.ensureBallast()) return false;
    EnsureOperandNotFloat32(alloc, call, MCall::IndexOfStackArg(i));
  }

  return true;
}

bool CallSetElementPolicy::adjustInputs(TempAllocator& alloc,
                                        MInstruction* ins) {
  // The first operand should be an object.
  if (!SingleObjectPolicy::staticAdjustInputs(alloc, ins)) return false;

  // Box the index and value operands.
  for (size_t i = 1, e = ins->numOperands(); i < e; i++) {
    MDefinition* in = ins->getOperand(i);
    if (in->type() == MIRType::Value) continue;
    ins->replaceOperand(i, BoxAt(alloc, ins, in));
  }
  return true;
}

bool InstanceOfPolicy::adjustInputs(TempAllocator& alloc, MInstruction* def) {
  // Box first operand if it isn't object
  if (def->getOperand(0)->type() != MIRType::Object)
    if (!BoxPolicy<0>::staticAdjustInputs(alloc, def)) return false;

  return true;
}

bool StoreUnboxedScalarPolicy::adjustValueInput(TempAllocator& alloc,
                                                MInstruction* ins,
                                                Scalar::Type writeType,
                                                MDefinition* value,
                                                int valueOperand) {
  // Storing a SIMD value requires a valueOperand that has already been
  // SimdUnboxed. See IonBuilder::inlineSimdStore(()
  if (Scalar::isSimdType(writeType)) {
    MOZ_ASSERT(IsSimdType(value->type()));
    return true;
  }

  MDefinition* curValue = value;
  // First, ensure the value is int32, boolean, double or Value.
  // The conversion is based on TypedArrayObjectTemplate::setElementTail.
  switch (value->type()) {
    case MIRType::Int32:
    case MIRType::Double:
    case MIRType::Float32:
    case MIRType::Boolean:
    case MIRType::Value:
      break;
    case MIRType::Null:
      value->setImplicitlyUsedUnchecked();
      value = MConstant::New(alloc, Int32Value(0));
      ins->block()->insertBefore(ins, value->toInstruction());
      break;
    case MIRType::Undefined:
      value->setImplicitlyUsedUnchecked();
      value = MConstant::New(alloc, DoubleNaNValue());
      ins->block()->insertBefore(ins, value->toInstruction());
      break;
    case MIRType::Object:
    case MIRType::String:
    case MIRType::Symbol:
      value = BoxAt(alloc, ins, value);
      break;
    default:
      MOZ_CRASH("Unexpected type");
  }

  if (value != curValue) {
    ins->replaceOperand(valueOperand, value);
    curValue = value;
  }

  MOZ_ASSERT(
      value->type() == MIRType::Int32 || value->type() == MIRType::Boolean ||
      value->type() == MIRType::Double || value->type() == MIRType::Float32 ||
      value->type() == MIRType::Value);

  switch (writeType) {
    case Scalar::Int8:
    case Scalar::Uint8:
    case Scalar::Int16:
    case Scalar::Uint16:
    case Scalar::Int32:
    case Scalar::Uint32:
      if (value->type() != MIRType::Int32) {
        value = MTruncateToInt32::New(alloc, value);
        ins->block()->insertBefore(ins, value->toInstruction());
      }
      break;
    case Scalar::Uint8Clamped:
      // IonBuilder should have inserted ClampToUint8.
      MOZ_ASSERT(value->type() == MIRType::Int32);
      break;
    case Scalar::Float32:
      if (value->type() != MIRType::Float32) {
        value = MToFloat32::New(alloc, value);
        ins->block()->insertBefore(ins, value->toInstruction());
      }
      break;
    case Scalar::Float64:
      if (value->type() != MIRType::Double) {
        value = MToDouble::New(alloc, value);
        ins->block()->insertBefore(ins, value->toInstruction());
      }
      break;
    default:
      MOZ_CRASH("Invalid array type");
  }

  if (value != curValue) ins->replaceOperand(valueOperand, value);

  return true;
}

bool StoreUnboxedScalarPolicy::adjustInputs(TempAllocator& alloc,
                                            MInstruction* ins) {
  if (!SingleObjectPolicy::staticAdjustInputs(alloc, ins)) return false;

  MStoreUnboxedScalar* store = ins->toStoreUnboxedScalar();
  MOZ_ASSERT(IsValidElementsType(store->elements(), store->offsetAdjustment()));
  MOZ_ASSERT(store->index()->type() == MIRType::Int32);

  return adjustValueInput(alloc, store, store->writeType(), store->value(), 2);
}

bool StoreTypedArrayHolePolicy::adjustInputs(TempAllocator& alloc,
                                             MInstruction* ins) {
  MStoreTypedArrayElementHole* store = ins->toStoreTypedArrayElementHole();
  MOZ_ASSERT(store->elements()->type() == MIRType::Elements);
  MOZ_ASSERT(store->index()->type() == MIRType::Int32);
  MOZ_ASSERT(store->length()->type() == MIRType::Int32);

  return StoreUnboxedScalarPolicy::adjustValueInput(
      alloc, ins, store->arrayType(), store->value(), 3);
}

bool StoreUnboxedObjectOrNullPolicy::adjustInputs(TempAllocator& alloc,
                                                  MInstruction* ins) {
  if (!ObjectPolicy<0>::staticAdjustInputs(alloc, ins)) return false;

  if (!ObjectPolicy<3>::staticAdjustInputs(alloc, ins)) return false;

  // Change the value input to a ToObjectOrNull instruction if it might be
  // a non-null primitive. Insert a post barrier for the instruction's object
  // and whatever its new value is, unless the value is definitely null.
  MStoreUnboxedObjectOrNull* store = ins->toStoreUnboxedObjectOrNull();

  MOZ_ASSERT(store->typedObj()->type() == MIRType::Object);

  MDefinition* value = store->value();
  if (value->type() == MIRType::Object || value->type() == MIRType::Null ||
      value->type() == MIRType::ObjectOrNull) {
    if (value->type() != MIRType::Null) {
      MInstruction* barrier =
          MPostWriteBarrier::New(alloc, store->typedObj(), value);
      store->block()->insertBefore(store, barrier);
    }
    return true;
  }

  MToObjectOrNull* replace = MToObjectOrNull::New(alloc, value);
  store->block()->insertBefore(store, replace);
  store->setValue(replace);

  if (!BoxPolicy<0>::staticAdjustInputs(alloc, replace)) return false;

  MInstruction* barrier =
      MPostWriteBarrier::New(alloc, store->typedObj(), replace);
  store->block()->insertBefore(store, barrier);

  return true;
}

bool StoreUnboxedStringPolicy::adjustInputs(TempAllocator& alloc,
                                            MInstruction* ins) {
  if (!ObjectPolicy<0>::staticAdjustInputs(alloc, ins)) return false;

  // Change the value input to a ToString instruction if it might be
  // a non-null primitive.
  if (!ConvertToStringPolicy<2>::staticAdjustInputs(alloc, ins)) return false;

  if (!ObjectPolicy<3>::staticAdjustInputs(alloc, ins)) return false;

  // Insert a post barrier for the instruction's object and whatever its new
  // value is.
  MStoreUnboxedString* store = ins->toStoreUnboxedString();

  MOZ_ASSERT(store->typedObj()->type() == MIRType::Object);

  MDefinition* value = store->value();
  MOZ_ASSERT(value->type() == MIRType::String);
  MInstruction* barrier =
      MPostWriteBarrier::New(alloc, store->typedObj(), value);
  store->block()->insertBefore(store, barrier);
  return true;
}

bool ClampPolicy::adjustInputs(TempAllocator& alloc, MInstruction* ins) {
  MDefinition* in = ins->toClampToUint8()->input();

  switch (in->type()) {
    case MIRType::Int32:
    case MIRType::Double:
    case MIRType::Value:
      break;
    default:
      ins->replaceOperand(0, BoxAt(alloc, ins, in));
      break;
  }

  return true;
}

bool FilterTypeSetPolicy::adjustInputs(TempAllocator& alloc,
                                       MInstruction* ins) {
  MOZ_ASSERT(ins->numOperands() == 1);
  MIRType inputType = ins->getOperand(0)->type();
  MIRType outputType = ins->type();

  // Special case when output is a Float32, but input isn't.
  if (outputType == MIRType::Float32 && inputType != MIRType::Float32) {
    // Create a MToFloat32 to add between the MFilterTypeSet and
    // its uses.
    MInstruction* replace = MToFloat32::New(alloc, ins);
    ins->justReplaceAllUsesWithExcept(replace);
    ins->block()->insertAfter(ins, replace);

    // Reset the type to not MIRType::Float32
    // Note: setResultType shouldn't happen in TypePolicies,
    //       Here it is fine, since there is just one use we just
    //       added ourself. And the resulting type after MToFloat32
    //       equals the original type.
    ins->setResultType(ins->resultTypeSet()->getKnownMIRType());
    outputType = ins->type();

    // Do the type analysis
    if (!replace->typePolicy()->adjustInputs(alloc, replace)) return false;

    // Fall through to let the MFilterTypeSet adjust its input based
    // on its new type.
  }

  // Input and output type are already in accordance.
  if (inputType == outputType) return true;

  // Output is a value, box the input.
  if (outputType == MIRType::Value) {
    MOZ_ASSERT(inputType != MIRType::Value);
    ins->replaceOperand(0, BoxAt(alloc, ins, ins->getOperand(0)));
    return true;
  }

  // The outputType should be a subset of the inputType else we are in code
  // that has never executed yet. Bail to see the new type (if that hasn't
  // happened yet).
  if (inputType != MIRType::Value) {
    MBail* bail = MBail::New(alloc);
    ins->block()->insertBefore(ins, bail);
    bail->setDependency(ins->dependency());
    ins->setDependency(bail);
    ins->replaceOperand(0, BoxAt(alloc, ins, ins->getOperand(0)));
  }

  // We can't unbox a value to null/undefined/lazyargs. So keep output
  // also a value.
  // Note: Using setResultType shouldn't be done in TypePolicies,
  //       Here it is fine, since the type barrier has no uses.
  if (IsNullOrUndefined(outputType) ||
      outputType == MIRType::MagicOptimizedArguments) {
    MOZ_ASSERT(!ins->hasDefUses());
    ins->setResultType(MIRType::Value);
    return true;
  }

  // Unbox / propagate the right type.
  MUnbox::Mode mode = MUnbox::Infallible;
  MInstruction* replace =
      MUnbox::New(alloc, ins->getOperand(0), ins->type(), mode);

  ins->block()->insertBefore(ins, replace);
  ins->replaceOperand(0, replace);
  if (!replace->typePolicy()->adjustInputs(alloc, replace)) return false;

  // Carry over the dependency the MFilterTypeSet had.
  replace->setDependency(ins->dependency());

  return true;
}

// Lists of all TypePolicy specializations which are used by MIR Instructions.
#define TYPE_POLICY_LIST(_)         \
  _(ArithPolicy)                    \
  _(BitwisePolicy)                  \
  _(BoxInputsPolicy)                \
  _(CallPolicy)                     \
  _(CallSetElementPolicy)           \
  _(ClampPolicy)                    \
  _(ComparePolicy)                  \
  _(FilterTypeSetPolicy)            \
  _(InstanceOfPolicy)               \
  _(PowPolicy)                      \
  _(SameValuePolicy)                \
  _(SimdAllPolicy)                  \
  _(SimdSelectPolicy)               \
  _(SimdShufflePolicy)              \
  _(StoreTypedArrayHolePolicy)      \
  _(StoreUnboxedScalarPolicy)       \
  _(StoreUnboxedObjectOrNullPolicy) \
  _(StoreUnboxedStringPolicy)       \
  _(TestPolicy)                     \
  _(AllDoublePolicy)                \
  _(ToDoublePolicy)                 \
  _(ToInt32Policy)                  \
  _(ToStringPolicy)                 \
  _(TypeBarrierPolicy)

#define TEMPLATE_TYPE_POLICY_LIST(_)                                          \
  _(BoxExceptPolicy<0, MIRType::Object>)                                      \
  _(BoxPolicy<0>)                                                             \
  _(ConvertToInt32Policy<0>)                                                  \
  _(ConvertToStringPolicy<0>)                                                 \
  _(ConvertToStringPolicy<2>)                                                 \
  _(DoublePolicy<0>)                                                          \
  _(FloatingPointPolicy<0>)                                                   \
  _(UnboxedInt32Policy<0>)                                                    \
  _(UnboxedInt32Policy<1>)                                                    \
  _(MixPolicy<ObjectPolicy<0>, StringPolicy<1>, BoxPolicy<2>>)                \
  _(MixPolicy<ObjectPolicy<0>, BoxPolicy<1>, BoxPolicy<2>>)                   \
  _(MixPolicy<ObjectPolicy<0>, BoxPolicy<1>, ObjectPolicy<2>>)                \
  _(MixPolicy<ObjectPolicy<0>, UnboxedInt32Policy<1>, BoxPolicy<2>>)          \
  _(MixPolicy<ObjectPolicy<0>, UnboxedInt32Policy<1>, UnboxedInt32Policy<2>>) \
  _(MixPolicy<ObjectPolicy<0>, UnboxedInt32Policy<1>,                         \
              TruncateToInt32Policy<2>>)                                      \
  _(MixPolicy<ObjectPolicy<0>, ObjectPolicy<1>, BoxPolicy<2>>)                \
  _(MixPolicy<ObjectPolicy<0>, ObjectPolicy<1>, UnboxedInt32Policy<2>>)       \
  _(MixPolicy<ObjectPolicy<0>, ObjectPolicy<1>, ObjectPolicy<2>>)             \
  _(MixPolicy<StringPolicy<0>, UnboxedInt32Policy<1>, UnboxedInt32Policy<2>>) \
  _(MixPolicy<StringPolicy<0>, ObjectPolicy<1>, StringPolicy<2>>)             \
  _(MixPolicy<StringPolicy<0>, StringPolicy<1>, StringPolicy<2>>)             \
  _(MixPolicy<ObjectPolicy<0>, StringPolicy<1>, UnboxedInt32Policy<2>>)       \
  _(MixPolicy<ObjectPolicy<0>, UnboxedInt32Policy<1>, UnboxedInt32Policy<2>,  \
              UnboxedInt32Policy<3>>)                                         \
  _(MixPolicy<ObjectPolicy<0>, UnboxedInt32Policy<1>,                         \
              TruncateToInt32Policy<2>, TruncateToInt32Policy<3>>)            \
  _(MixPolicy<ObjectPolicy<0>, CacheIdPolicy<1>, NoFloatPolicy<2>>)           \
  _(MixPolicy<SimdScalarPolicy<0>, SimdScalarPolicy<1>, SimdScalarPolicy<2>,  \
              SimdScalarPolicy<3>>)                                           \
  _(MixPolicy<ObjectPolicy<0>, BoxExceptPolicy<1, MIRType::Object>,           \
              CacheIdPolicy<2>>)                                              \
  _(MixPolicy<BoxPolicy<0>, ObjectPolicy<1>>)                                 \
  _(MixPolicy<ConvertToStringPolicy<0>, ConvertToStringPolicy<1>>)            \
  _(MixPolicy<ConvertToStringPolicy<0>, ObjectPolicy<1>>)                     \
  _(MixPolicy<DoublePolicy<0>, DoublePolicy<1>>)                              \
  _(MixPolicy<UnboxedInt32Policy<0>, UnboxedInt32Policy<1>>)                  \
  _(MixPolicy<ObjectPolicy<0>, BoxPolicy<1>>)                                 \
  _(MixPolicy<BoxExceptPolicy<0, MIRType::Object>, CacheIdPolicy<1>>)         \
  _(MixPolicy<CacheIdPolicy<0>, ObjectPolicy<1>>)                             \
  _(MixPolicy<ObjectPolicy<0>, ConvertToStringPolicy<1>>)                     \
  _(MixPolicy<ObjectPolicy<0>, UnboxedInt32Policy<1>>)                        \
  _(MixPolicy<ObjectPolicy<0>, UnboxedInt32Policy<2>>)                        \
  _(MixPolicy<ObjectPolicy<0>, NoFloatPolicy<1>>)                             \
  _(MixPolicy<ObjectPolicy<0>, NoFloatPolicy<2>>)                             \
  _(MixPolicy<ObjectPolicy<0>, NoFloatPolicy<3>>)                             \
  _(MixPolicy<ObjectPolicy<0>, ObjectPolicy<1>>)                              \
  _(MixPolicy<ObjectPolicy<0>, StringPolicy<1>>)                              \
  _(MixPolicy<ObjectPolicy<0>, ConvertToStringPolicy<2>>)                     \
  _(MixPolicy<ObjectPolicy<1>, ConvertToStringPolicy<0>>)                     \
  _(MixPolicy<SimdSameAsReturnedTypePolicy<0>,                                \
              SimdSameAsReturnedTypePolicy<1>>)                               \
  _(MixPolicy<SimdSameAsReturnedTypePolicy<0>, SimdScalarPolicy<1>>)          \
  _(MixPolicy<StringPolicy<0>, UnboxedInt32Policy<1>>)                        \
  _(MixPolicy<StringPolicy<0>, StringPolicy<1>>)                              \
  _(MixPolicy<BoxPolicy<0>, BoxPolicy<1>>)                                    \
  _(NoFloatPolicy<0>)                                                         \
  _(NoFloatPolicyAfter<0>)                                                    \
  _(NoFloatPolicyAfter<1>)                                                    \
  _(NoFloatPolicyAfter<2>)                                                    \
  _(ObjectPolicy<0>)                                                          \
  _(ObjectPolicy<1>)                                                          \
  _(ObjectPolicy<3>)                                                          \
  _(SimdPolicy<0>)                                                            \
  _(SimdSameAsReturnedTypePolicy<0>)                                          \
  _(SimdScalarPolicy<0>)                                                      \
  _(StringPolicy<0>)

namespace js {
namespace jit {

// Define for all used TypePolicy specialization, the definition for
// |TypePolicy::Data::thisTypePolicy|.  This function returns one constant
// instance of the TypePolicy which is shared among all MIR Instructions of the
// same type.
//
// This Macro use __VA_ARGS__ to account for commas of template parameters.
#define DEFINE_TYPE_POLICY_SINGLETON_INSTANCES_(...) \
  TypePolicy* __VA_ARGS__::Data::thisTypePolicy() {  \
    static __VA_ARGS__ singletonType;                \
    return &singletonType;                           \
  }

TYPE_POLICY_LIST(DEFINE_TYPE_POLICY_SINGLETON_INSTANCES_)
TEMPLATE_TYPE_POLICY_LIST(template <> DEFINE_TYPE_POLICY_SINGLETON_INSTANCES_)
#undef DEFINE_TYPE_POLICY_SINGLETON_INSTANCES_

}  // namespace jit
}  // namespace js

namespace {

// For extra-good measure in case an unqualified use is ever introduced.  (The
// main use in the macro below is explicitly qualified so as not to consult
// this scope and find this function.)
inline TypePolicy* thisTypePolicy() = delete;

static MIRType thisTypeSpecialization() {
  MOZ_CRASH("TypeSpecialization lacks definition of thisTypeSpecialization.");
}

}  // namespace

// For each MIR Instruction, this macro define the |typePolicy| method which is
// using the |thisTypePolicy| method.  The |thisTypePolicy| method is either a
// member of the MIR Instruction, such as with MGetElementCache, a member
// inherited from the TypePolicy::Data structure, or a member inherited from
// NoTypePolicy if the MIR instruction has no type policy.
#define DEFINE_MIR_TYPEPOLICY_MEMBERS_(op)                                     \
  TypePolicy* js::jit::M##op::typePolicy() { return M##op::thisTypePolicy(); } \
                                                                               \
  MIRType js::jit::M##op::typePolicySpecialization() {                         \
    return thisTypeSpecialization();                                           \
  }

MIR_OPCODE_LIST(DEFINE_MIR_TYPEPOLICY_MEMBERS_)
#undef DEFINE_MIR_TYPEPOLICY_MEMBERS_