// 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/instruction-selector.h"

#include <limits>

#include "src/base/adapters.h"
#include "src/compiler/instruction-selector-impl.h"
#include "src/compiler/node-matchers.h"
#include "src/compiler/pipeline.h"
#include "src/compiler/schedule.h"
#include "src/compiler/state-values-utils.h"

namespace v8 {
namespace internal {
namespace compiler {

InstructionSelector::InstructionSelector(
    Zone* zone, size_t node_count, Linkage* linkage,
    InstructionSequence* sequence, Schedule* schedule,
    SourcePositionTable* source_positions,
    SourcePositionMode source_position_mode, Features features)
    : zone_(zone),
      linkage_(linkage),
      sequence_(sequence),
      source_positions_(source_positions),
      source_position_mode_(source_position_mode),
      features_(features),
      schedule_(schedule),
      current_block_(NULL),
      instructions_(zone),
      defined_(node_count, false, zone),
      used_(node_count, false, zone),
      virtual_registers_(node_count,
                         InstructionOperand::kInvalidVirtualRegister, zone) {
  instructions_.reserve(node_count);
}


void InstructionSelector::SelectInstructions() {
  // Mark the inputs of all phis in loop headers as used.
  BasicBlockVector* blocks = schedule()->rpo_order();
  for (auto const block : *blocks) {
    if (!block->IsLoopHeader()) continue;
    DCHECK_LE(2u, block->PredecessorCount());
    for (Node* const phi : *block) {
      if (phi->opcode() != IrOpcode::kPhi) continue;

      // Mark all inputs as used.
      for (Node* const input : phi->inputs()) {
        MarkAsUsed(input);
      }
    }
  }

  // Visit each basic block in post order.
  for (auto i = blocks->rbegin(); i != blocks->rend(); ++i) {
    VisitBlock(*i);
  }

  // Schedule the selected instructions.
  for (auto const block : *blocks) {
    InstructionBlock* instruction_block =
        sequence()->InstructionBlockAt(RpoNumber::FromInt(block->rpo_number()));
    size_t end = instruction_block->code_end();
    size_t start = instruction_block->code_start();
    DCHECK_LE(end, start);
    sequence()->StartBlock(RpoNumber::FromInt(block->rpo_number()));
    while (start-- > end) {
      sequence()->AddInstruction(instructions_[start]);
    }
    sequence()->EndBlock(RpoNumber::FromInt(block->rpo_number()));
  }
}


Instruction* InstructionSelector::Emit(InstructionCode opcode,
                                       InstructionOperand output,
                                       size_t temp_count,
                                       InstructionOperand* temps) {
  size_t output_count = output.IsInvalid() ? 0 : 1;
  return Emit(opcode, output_count, &output, 0, NULL, temp_count, temps);
}


Instruction* InstructionSelector::Emit(InstructionCode opcode,
                                       InstructionOperand output,
                                       InstructionOperand a, size_t temp_count,
                                       InstructionOperand* temps) {
  size_t output_count = output.IsInvalid() ? 0 : 1;
  return Emit(opcode, output_count, &output, 1, &a, temp_count, temps);
}


Instruction* InstructionSelector::Emit(InstructionCode opcode,
                                       InstructionOperand output,
                                       InstructionOperand a,
                                       InstructionOperand b, size_t temp_count,
                                       InstructionOperand* temps) {
  size_t output_count = output.IsInvalid() ? 0 : 1;
  InstructionOperand inputs[] = {a, b};
  size_t input_count = arraysize(inputs);
  return Emit(opcode, output_count, &output, input_count, inputs, temp_count,
              temps);
}


Instruction* InstructionSelector::Emit(InstructionCode opcode,
                                       InstructionOperand output,
                                       InstructionOperand a,
                                       InstructionOperand b,
                                       InstructionOperand c, size_t temp_count,
                                       InstructionOperand* temps) {
  size_t output_count = output.IsInvalid() ? 0 : 1;
  InstructionOperand inputs[] = {a, b, c};
  size_t input_count = arraysize(inputs);
  return Emit(opcode, output_count, &output, input_count, inputs, temp_count,
              temps);
}


Instruction* InstructionSelector::Emit(
    InstructionCode opcode, InstructionOperand output, InstructionOperand a,
    InstructionOperand b, InstructionOperand c, InstructionOperand d,
    size_t temp_count, InstructionOperand* temps) {
  size_t output_count = output.IsInvalid() ? 0 : 1;
  InstructionOperand inputs[] = {a, b, c, d};
  size_t input_count = arraysize(inputs);
  return Emit(opcode, output_count, &output, input_count, inputs, temp_count,
              temps);
}


Instruction* InstructionSelector::Emit(
    InstructionCode opcode, InstructionOperand output, InstructionOperand a,
    InstructionOperand b, InstructionOperand c, InstructionOperand d,
    InstructionOperand e, size_t temp_count, InstructionOperand* temps) {
  size_t output_count = output.IsInvalid() ? 0 : 1;
  InstructionOperand inputs[] = {a, b, c, d, e};
  size_t input_count = arraysize(inputs);
  return Emit(opcode, output_count, &output, input_count, inputs, temp_count,
              temps);
}


Instruction* InstructionSelector::Emit(
    InstructionCode opcode, InstructionOperand output, InstructionOperand a,
    InstructionOperand b, InstructionOperand c, InstructionOperand d,
    InstructionOperand e, InstructionOperand f, size_t temp_count,
    InstructionOperand* temps) {
  size_t output_count = output.IsInvalid() ? 0 : 1;
  InstructionOperand inputs[] = {a, b, c, d, e, f};
  size_t input_count = arraysize(inputs);
  return Emit(opcode, output_count, &output, input_count, inputs, temp_count,
              temps);
}


Instruction* InstructionSelector::Emit(
    InstructionCode opcode, size_t output_count, InstructionOperand* outputs,
    size_t input_count, InstructionOperand* inputs, size_t temp_count,
    InstructionOperand* temps) {
  Instruction* instr =
      Instruction::New(instruction_zone(), opcode, output_count, outputs,
                       input_count, inputs, temp_count, temps);
  return Emit(instr);
}


Instruction* InstructionSelector::Emit(Instruction* instr) {
  instructions_.push_back(instr);
  return instr;
}


bool InstructionSelector::CanCover(Node* user, Node* node) const {
  return node->OwnedBy(user) &&
         schedule()->block(node) == schedule()->block(user);
}


int InstructionSelector::GetVirtualRegister(const Node* node) {
  DCHECK_NOT_NULL(node);
  size_t const id = node->id();
  DCHECK_LT(id, virtual_registers_.size());
  int virtual_register = virtual_registers_[id];
  if (virtual_register == InstructionOperand::kInvalidVirtualRegister) {
    virtual_register = sequence()->NextVirtualRegister();
    virtual_registers_[id] = virtual_register;
  }
  return virtual_register;
}


const std::map<NodeId, int> InstructionSelector::GetVirtualRegistersForTesting()
    const {
  std::map<NodeId, int> virtual_registers;
  for (size_t n = 0; n < virtual_registers_.size(); ++n) {
    if (virtual_registers_[n] != InstructionOperand::kInvalidVirtualRegister) {
      NodeId const id = static_cast<NodeId>(n);
      virtual_registers.insert(std::make_pair(id, virtual_registers_[n]));
    }
  }
  return virtual_registers;
}


bool InstructionSelector::IsDefined(Node* node) const {
  DCHECK_NOT_NULL(node);
  size_t const id = node->id();
  DCHECK_LT(id, defined_.size());
  return defined_[id];
}


void InstructionSelector::MarkAsDefined(Node* node) {
  DCHECK_NOT_NULL(node);
  size_t const id = node->id();
  DCHECK_LT(id, defined_.size());
  defined_[id] = true;
}


bool InstructionSelector::IsUsed(Node* node) const {
  DCHECK_NOT_NULL(node);
  if (!node->op()->HasProperty(Operator::kEliminatable)) return true;
  size_t const id = node->id();
  DCHECK_LT(id, used_.size());
  return used_[id];
}


void InstructionSelector::MarkAsUsed(Node* node) {
  DCHECK_NOT_NULL(node);
  size_t const id = node->id();
  DCHECK_LT(id, used_.size());
  used_[id] = true;
}


void InstructionSelector::MarkAsRepresentation(MachineType rep,
                                               const InstructionOperand& op) {
  UnallocatedOperand unalloc = UnallocatedOperand::cast(op);
  rep = RepresentationOf(rep);
  sequence()->MarkAsRepresentation(rep, unalloc.virtual_register());
}


void InstructionSelector::MarkAsRepresentation(MachineType rep, Node* node) {
  rep = RepresentationOf(rep);
  sequence()->MarkAsRepresentation(rep, GetVirtualRegister(node));
}


// TODO(bmeurer): Get rid of the CallBuffer business and make
// InstructionSelector::VisitCall platform independent instead.
CallBuffer::CallBuffer(Zone* zone, const CallDescriptor* d,
                       FrameStateDescriptor* frame_desc)
    : descriptor(d),
      frame_state_descriptor(frame_desc),
      output_nodes(zone),
      outputs(zone),
      instruction_args(zone),
      pushed_nodes(zone) {
  output_nodes.reserve(d->ReturnCount());
  outputs.reserve(d->ReturnCount());
  pushed_nodes.reserve(input_count());
  instruction_args.reserve(input_count() + frame_state_value_count());
}


// TODO(bmeurer): Get rid of the CallBuffer business and make
// InstructionSelector::VisitCall platform independent instead.
void InstructionSelector::InitializeCallBuffer(Node* call, CallBuffer* buffer,
                                               bool call_code_immediate,
                                               bool call_address_immediate) {
  OperandGenerator g(this);
  DCHECK_LE(call->op()->ValueOutputCount(),
            static_cast<int>(buffer->descriptor->ReturnCount()));
  DCHECK_EQ(
      call->op()->ValueInputCount(),
      static_cast<int>(buffer->input_count() + buffer->frame_state_count()));

  if (buffer->descriptor->ReturnCount() > 0) {
    // Collect the projections that represent multiple outputs from this call.
    if (buffer->descriptor->ReturnCount() == 1) {
      buffer->output_nodes.push_back(call);
    } else {
      buffer->output_nodes.resize(buffer->descriptor->ReturnCount(), nullptr);
      for (auto use : call->uses()) {
        if (use->opcode() != IrOpcode::kProjection) continue;
        size_t const index = ProjectionIndexOf(use->op());
        DCHECK_LT(index, buffer->output_nodes.size());
        DCHECK(!buffer->output_nodes[index]);
        buffer->output_nodes[index] = use;
      }
    }

    // Filter out the outputs that aren't live because no projection uses them.
    size_t outputs_needed_by_framestate =
        buffer->frame_state_descriptor == NULL
            ? 0
            : buffer->frame_state_descriptor->state_combine()
                  .ConsumedOutputCount();
    for (size_t i = 0; i < buffer->output_nodes.size(); i++) {
      bool output_is_live =
          buffer->output_nodes[i] != NULL || i < outputs_needed_by_framestate;
      if (output_is_live) {
        MachineType type =
            buffer->descriptor->GetReturnType(static_cast<int>(i));
        LinkageLocation location =
            buffer->descriptor->GetReturnLocation(static_cast<int>(i));

        Node* output = buffer->output_nodes[i];
        InstructionOperand op =
            output == NULL ? g.TempLocation(location, type)
                           : g.DefineAsLocation(output, location, type);
        MarkAsRepresentation(type, op);

        buffer->outputs.push_back(op);
      }
    }
  }

  // The first argument is always the callee code.
  Node* callee = call->InputAt(0);
  switch (buffer->descriptor->kind()) {
    case CallDescriptor::kCallCodeObject:
      buffer->instruction_args.push_back(
          (call_code_immediate && callee->opcode() == IrOpcode::kHeapConstant)
              ? g.UseImmediate(callee)
              : g.UseRegister(callee));
      break;
    case CallDescriptor::kCallAddress:
      buffer->instruction_args.push_back(
          (call_address_immediate &&
           (callee->opcode() == IrOpcode::kInt32Constant ||
            callee->opcode() == IrOpcode::kInt64Constant))
              ? g.UseImmediate(callee)
              : g.UseRegister(callee));
      break;
    case CallDescriptor::kCallJSFunction:
      buffer->instruction_args.push_back(
          g.UseLocation(callee, buffer->descriptor->GetInputLocation(0),
                        buffer->descriptor->GetInputType(0)));
      break;
  }
  DCHECK_EQ(1u, buffer->instruction_args.size());

  // If the call needs a frame state, we insert the state information as
  // follows (n is the number of value inputs to the frame state):
  // arg 1               : deoptimization id.
  // arg 2 - arg (n + 1) : value inputs to the frame state.
  if (buffer->frame_state_descriptor != NULL) {
    InstructionSequence::StateId state_id =
        sequence()->AddFrameStateDescriptor(buffer->frame_state_descriptor);
    buffer->instruction_args.push_back(g.TempImmediate(state_id.ToInt()));

    Node* frame_state =
        call->InputAt(static_cast<int>(buffer->descriptor->InputCount()));
    AddFrameStateInputs(frame_state, &buffer->instruction_args,
                        buffer->frame_state_descriptor);
  }
  DCHECK(1 + buffer->frame_state_value_count() ==
         buffer->instruction_args.size());

  size_t input_count = static_cast<size_t>(buffer->input_count());

  // Split the arguments into pushed_nodes and instruction_args. Pushed
  // arguments require an explicit push instruction before the call and do
  // not appear as arguments to the call. Everything else ends up
  // as an InstructionOperand argument to the call.
  auto iter(call->inputs().begin());
  int pushed_count = 0;
  for (size_t index = 0; index < input_count; ++iter, ++index) {
    DCHECK(iter != call->inputs().end());
    DCHECK((*iter)->op()->opcode() != IrOpcode::kFrameState);
    if (index == 0) continue;  // The first argument (callee) is already done.
    InstructionOperand op =
        g.UseLocation(*iter, buffer->descriptor->GetInputLocation(index),
                      buffer->descriptor->GetInputType(index));
    if (UnallocatedOperand::cast(op).HasFixedSlotPolicy()) {
      int stack_index = -UnallocatedOperand::cast(op).fixed_slot_index() - 1;
      if (static_cast<size_t>(stack_index) >= buffer->pushed_nodes.size()) {
        buffer->pushed_nodes.resize(stack_index + 1, NULL);
      }
      DCHECK(!buffer->pushed_nodes[stack_index]);
      buffer->pushed_nodes[stack_index] = *iter;
      pushed_count++;
    } else {
      buffer->instruction_args.push_back(op);
    }
  }
  CHECK_EQ(pushed_count, static_cast<int>(buffer->pushed_nodes.size()));
  DCHECK(static_cast<size_t>(input_count) ==
         (buffer->instruction_args.size() + buffer->pushed_nodes.size() -
          buffer->frame_state_value_count()));
}


void InstructionSelector::VisitBlock(BasicBlock* block) {
  DCHECK(!current_block_);
  current_block_ = block;
  int current_block_end = static_cast<int>(instructions_.size());

  // Generate code for the block control "top down", but schedule the code
  // "bottom up".
  VisitControl(block);
  std::reverse(instructions_.begin() + current_block_end, instructions_.end());

  // Visit code in reverse control flow order, because architecture-specific
  // matching may cover more than one node at a time.
  for (auto node : base::Reversed(*block)) {
    // Skip nodes that are unused or already defined.
    if (!IsUsed(node) || IsDefined(node)) continue;
    // Generate code for this node "top down", but schedule the code "bottom
    // up".
    size_t current_node_end = instructions_.size();
    VisitNode(node);
    std::reverse(instructions_.begin() + current_node_end, instructions_.end());
    if (instructions_.size() == current_node_end) continue;
    // Mark source position on first instruction emitted.
    SourcePosition source_position = source_positions_->GetSourcePosition(node);
    if (source_position.IsUnknown()) continue;
    DCHECK(!source_position.IsInvalid());
    if (source_position_mode_ == kAllSourcePositions ||
        node->opcode() == IrOpcode::kCall) {
      sequence()->SetSourcePosition(instructions_[current_node_end],
                                    source_position);
    }
  }

  // We're done with the block.
  InstructionBlock* instruction_block =
      sequence()->InstructionBlockAt(RpoNumber::FromInt(block->rpo_number()));
  instruction_block->set_code_start(static_cast<int>(instructions_.size()));
  instruction_block->set_code_end(current_block_end);

  current_block_ = NULL;
}


void InstructionSelector::VisitControl(BasicBlock* block) {
#ifdef DEBUG
  // SSA deconstruction requires targets of branches not to have phis.
  // Edge split form guarantees this property, but is more strict.
  if (block->SuccessorCount() > 1) {
    for (BasicBlock* const successor : block->successors()) {
      for (Node* const node : *successor) {
        CHECK(!IrOpcode::IsPhiOpcode(node->opcode()));
      }
    }
  }
#endif

  Node* input = block->control_input();
  switch (block->control()) {
    case BasicBlock::kGoto:
      return VisitGoto(block->SuccessorAt(0));
    case BasicBlock::kCall: {
      DCHECK_EQ(IrOpcode::kCall, input->opcode());
      BasicBlock* success = block->SuccessorAt(0);
      BasicBlock* exception = block->SuccessorAt(1);
      return VisitCall(input, exception), VisitGoto(success);
    }
    case BasicBlock::kTailCall: {
      DCHECK_EQ(IrOpcode::kTailCall, input->opcode());
      return VisitTailCall(input);
    }
    case BasicBlock::kBranch: {
      DCHECK_EQ(IrOpcode::kBranch, input->opcode());
      BasicBlock* tbranch = block->SuccessorAt(0);
      BasicBlock* fbranch = block->SuccessorAt(1);
      if (tbranch == fbranch) return VisitGoto(tbranch);
      return VisitBranch(input, tbranch, fbranch);
    }
    case BasicBlock::kSwitch: {
      DCHECK_EQ(IrOpcode::kSwitch, input->opcode());
      SwitchInfo sw;
      // Last successor must be Default.
      sw.default_branch = block->successors().back();
      DCHECK_EQ(IrOpcode::kIfDefault, sw.default_branch->front()->opcode());
      // All other successors must be cases.
      sw.case_count = block->SuccessorCount() - 1;
      DCHECK_LE(1u, sw.case_count);
      sw.case_branches = &block->successors().front();
      // Determine case values and their min/max.
      sw.case_values = zone()->NewArray<int32_t>(sw.case_count);
      sw.min_value = std::numeric_limits<int32_t>::max();
      sw.max_value = std::numeric_limits<int32_t>::min();
      for (size_t index = 0; index < sw.case_count; ++index) {
        BasicBlock* branch = sw.case_branches[index];
        int32_t value = OpParameter<int32_t>(branch->front()->op());
        sw.case_values[index] = value;
        if (sw.min_value > value) sw.min_value = value;
        if (sw.max_value < value) sw.max_value = value;
      }
      DCHECK_LE(sw.min_value, sw.max_value);
      // Note that {value_range} can be 0 if {min_value} is -2^31 and
      // {max_value}
      // is 2^31-1, so don't assume that it's non-zero below.
      sw.value_range = 1u + bit_cast<uint32_t>(sw.max_value) -
                       bit_cast<uint32_t>(sw.min_value);
      return VisitSwitch(input, sw);
    }
    case BasicBlock::kReturn: {
      DCHECK_EQ(IrOpcode::kReturn, input->opcode());
      return VisitReturn(input->InputAt(0));
    }
    case BasicBlock::kDeoptimize: {
      // If the result itself is a return, return its input.
      Node* value =
          (input != nullptr && input->opcode() == IrOpcode::kDeoptimize)
              ? input->InputAt(0)
              : input;
      return VisitDeoptimize(value);
    }
    case BasicBlock::kThrow:
      DCHECK_EQ(IrOpcode::kThrow, input->opcode());
      return VisitThrow(input->InputAt(0));
    case BasicBlock::kNone: {
      // TODO(titzer): exit block doesn't have control.
      DCHECK_NULL(input);
      break;
    }
    default:
      UNREACHABLE();
      break;
  }
}


void InstructionSelector::VisitNode(Node* node) {
  DCHECK_NOT_NULL(schedule()->block(node));  // should only use scheduled nodes.
  switch (node->opcode()) {
    case IrOpcode::kStart:
    case IrOpcode::kLoop:
    case IrOpcode::kEnd:
    case IrOpcode::kBranch:
    case IrOpcode::kIfTrue:
    case IrOpcode::kIfFalse:
    case IrOpcode::kIfSuccess:
    case IrOpcode::kSwitch:
    case IrOpcode::kIfValue:
    case IrOpcode::kIfDefault:
    case IrOpcode::kEffectPhi:
    case IrOpcode::kMerge:
    case IrOpcode::kTerminate:
      // No code needed for these graph artifacts.
      return;
    case IrOpcode::kIfException:
      return MarkAsReference(node), VisitIfException(node);
    case IrOpcode::kFinish:
      return MarkAsReference(node), VisitFinish(node);
    case IrOpcode::kParameter: {
      MachineType type =
          linkage()->GetParameterType(ParameterIndexOf(node->op()));
      MarkAsRepresentation(type, node);
      return VisitParameter(node);
    }
    case IrOpcode::kOsrValue:
      return MarkAsReference(node), VisitOsrValue(node);
    case IrOpcode::kPhi: {
      MachineType type = OpParameter<MachineType>(node);
      MarkAsRepresentation(type, node);
      return VisitPhi(node);
    }
    case IrOpcode::kProjection:
      return VisitProjection(node);
    case IrOpcode::kInt32Constant:
    case IrOpcode::kInt64Constant:
    case IrOpcode::kExternalConstant:
      return VisitConstant(node);
    case IrOpcode::kFloat32Constant:
      return MarkAsFloat32(node), VisitConstant(node);
    case IrOpcode::kFloat64Constant:
      return MarkAsFloat64(node), VisitConstant(node);
    case IrOpcode::kHeapConstant:
      return MarkAsReference(node), VisitConstant(node);
    case IrOpcode::kNumberConstant: {
      double value = OpParameter<double>(node);
      if (!IsSmiDouble(value)) MarkAsReference(node);
      return VisitConstant(node);
    }
    case IrOpcode::kCall:
      return VisitCall(node);
    case IrOpcode::kFrameState:
    case IrOpcode::kStateValues:
      return;
    case IrOpcode::kLoad: {
      LoadRepresentation rep = OpParameter<LoadRepresentation>(node);
      MarkAsRepresentation(rep, node);
      return VisitLoad(node);
    }
    case IrOpcode::kStore:
      return VisitStore(node);
    case IrOpcode::kWord32And:
      return MarkAsWord32(node), VisitWord32And(node);
    case IrOpcode::kWord32Or:
      return MarkAsWord32(node), VisitWord32Or(node);
    case IrOpcode::kWord32Xor:
      return MarkAsWord32(node), VisitWord32Xor(node);
    case IrOpcode::kWord32Shl:
      return MarkAsWord32(node), VisitWord32Shl(node);
    case IrOpcode::kWord32Shr:
      return MarkAsWord32(node), VisitWord32Shr(node);
    case IrOpcode::kWord32Sar:
      return MarkAsWord32(node), VisitWord32Sar(node);
    case IrOpcode::kWord32Ror:
      return MarkAsWord32(node), VisitWord32Ror(node);
    case IrOpcode::kWord32Equal:
      return VisitWord32Equal(node);
    case IrOpcode::kWord32Clz:
      return MarkAsWord32(node), VisitWord32Clz(node);
    case IrOpcode::kWord64And:
      return MarkAsWord64(node), VisitWord64And(node);
    case IrOpcode::kWord64Or:
      return MarkAsWord64(node), VisitWord64Or(node);
    case IrOpcode::kWord64Xor:
      return MarkAsWord64(node), VisitWord64Xor(node);
    case IrOpcode::kWord64Shl:
      return MarkAsWord64(node), VisitWord64Shl(node);
    case IrOpcode::kWord64Shr:
      return MarkAsWord64(node), VisitWord64Shr(node);
    case IrOpcode::kWord64Sar:
      return MarkAsWord64(node), VisitWord64Sar(node);
    case IrOpcode::kWord64Ror:
      return MarkAsWord64(node), VisitWord64Ror(node);
    case IrOpcode::kWord64Equal:
      return VisitWord64Equal(node);
    case IrOpcode::kInt32Add:
      return MarkAsWord32(node), VisitInt32Add(node);
    case IrOpcode::kInt32AddWithOverflow:
      return MarkAsWord32(node), VisitInt32AddWithOverflow(node);
    case IrOpcode::kInt32Sub:
      return MarkAsWord32(node), VisitInt32Sub(node);
    case IrOpcode::kInt32SubWithOverflow:
      return VisitInt32SubWithOverflow(node);
    case IrOpcode::kInt32Mul:
      return MarkAsWord32(node), VisitInt32Mul(node);
    case IrOpcode::kInt32MulHigh:
      return VisitInt32MulHigh(node);
    case IrOpcode::kInt32Div:
      return MarkAsWord32(node), VisitInt32Div(node);
    case IrOpcode::kInt32Mod:
      return MarkAsWord32(node), VisitInt32Mod(node);
    case IrOpcode::kInt32LessThan:
      return VisitInt32LessThan(node);
    case IrOpcode::kInt32LessThanOrEqual:
      return VisitInt32LessThanOrEqual(node);
    case IrOpcode::kUint32Div:
      return MarkAsWord32(node), VisitUint32Div(node);
    case IrOpcode::kUint32LessThan:
      return VisitUint32LessThan(node);
    case IrOpcode::kUint32LessThanOrEqual:
      return VisitUint32LessThanOrEqual(node);
    case IrOpcode::kUint32Mod:
      return MarkAsWord32(node), VisitUint32Mod(node);
    case IrOpcode::kUint32MulHigh:
      return VisitUint32MulHigh(node);
    case IrOpcode::kInt64Add:
      return MarkAsWord64(node), VisitInt64Add(node);
    case IrOpcode::kInt64Sub:
      return MarkAsWord64(node), VisitInt64Sub(node);
    case IrOpcode::kInt64Mul:
      return MarkAsWord64(node), VisitInt64Mul(node);
    case IrOpcode::kInt64Div:
      return MarkAsWord64(node), VisitInt64Div(node);
    case IrOpcode::kInt64Mod:
      return MarkAsWord64(node), VisitInt64Mod(node);
    case IrOpcode::kInt64LessThan:
      return VisitInt64LessThan(node);
    case IrOpcode::kInt64LessThanOrEqual:
      return VisitInt64LessThanOrEqual(node);
    case IrOpcode::kUint64Div:
      return MarkAsWord64(node), VisitUint64Div(node);
    case IrOpcode::kUint64LessThan:
      return VisitUint64LessThan(node);
    case IrOpcode::kUint64Mod:
      return MarkAsWord64(node), VisitUint64Mod(node);
    case IrOpcode::kChangeFloat32ToFloat64:
      return MarkAsFloat64(node), VisitChangeFloat32ToFloat64(node);
    case IrOpcode::kChangeInt32ToFloat64:
      return MarkAsFloat64(node), VisitChangeInt32ToFloat64(node);
    case IrOpcode::kChangeUint32ToFloat64:
      return MarkAsFloat64(node), VisitChangeUint32ToFloat64(node);
    case IrOpcode::kChangeFloat64ToInt32:
      return MarkAsWord32(node), VisitChangeFloat64ToInt32(node);
    case IrOpcode::kChangeFloat64ToUint32:
      return MarkAsWord32(node), VisitChangeFloat64ToUint32(node);
    case IrOpcode::kChangeInt32ToInt64:
      return MarkAsWord64(node), VisitChangeInt32ToInt64(node);
    case IrOpcode::kChangeUint32ToUint64:
      return MarkAsWord64(node), VisitChangeUint32ToUint64(node);
    case IrOpcode::kTruncateFloat64ToFloat32:
      return MarkAsFloat32(node), VisitTruncateFloat64ToFloat32(node);
    case IrOpcode::kTruncateFloat64ToInt32:
      return MarkAsWord32(node), VisitTruncateFloat64ToInt32(node);
    case IrOpcode::kTruncateInt64ToInt32:
      return MarkAsWord32(node), VisitTruncateInt64ToInt32(node);
    case IrOpcode::kFloat32Add:
      return MarkAsFloat32(node), VisitFloat32Add(node);
    case IrOpcode::kFloat32Sub:
      return MarkAsFloat32(node), VisitFloat32Sub(node);
    case IrOpcode::kFloat32Mul:
      return MarkAsFloat32(node), VisitFloat32Mul(node);
    case IrOpcode::kFloat32Div:
      return MarkAsFloat32(node), VisitFloat32Div(node);
    case IrOpcode::kFloat32Min:
      return MarkAsFloat32(node), VisitFloat32Min(node);
    case IrOpcode::kFloat32Max:
      return MarkAsFloat32(node), VisitFloat32Max(node);
    case IrOpcode::kFloat32Abs:
      return MarkAsFloat32(node), VisitFloat32Abs(node);
    case IrOpcode::kFloat32Sqrt:
      return MarkAsFloat32(node), VisitFloat32Sqrt(node);
    case IrOpcode::kFloat32Equal:
      return VisitFloat32Equal(node);
    case IrOpcode::kFloat32LessThan:
      return VisitFloat32LessThan(node);
    case IrOpcode::kFloat32LessThanOrEqual:
      return VisitFloat32LessThanOrEqual(node);
    case IrOpcode::kFloat64Add:
      return MarkAsFloat64(node), VisitFloat64Add(node);
    case IrOpcode::kFloat64Sub:
      return MarkAsFloat64(node), VisitFloat64Sub(node);
    case IrOpcode::kFloat64Mul:
      return MarkAsFloat64(node), VisitFloat64Mul(node);
    case IrOpcode::kFloat64Div:
      return MarkAsFloat64(node), VisitFloat64Div(node);
    case IrOpcode::kFloat64Mod:
      return MarkAsFloat64(node), VisitFloat64Mod(node);
    case IrOpcode::kFloat64Min:
      return MarkAsFloat64(node), VisitFloat64Min(node);
    case IrOpcode::kFloat64Max:
      return MarkAsFloat64(node), VisitFloat64Max(node);
    case IrOpcode::kFloat64Abs:
      return MarkAsFloat64(node), VisitFloat64Abs(node);
    case IrOpcode::kFloat64Sqrt:
      return MarkAsFloat64(node), VisitFloat64Sqrt(node);
    case IrOpcode::kFloat64Equal:
      return VisitFloat64Equal(node);
    case IrOpcode::kFloat64LessThan:
      return VisitFloat64LessThan(node);
    case IrOpcode::kFloat64LessThanOrEqual:
      return VisitFloat64LessThanOrEqual(node);
    case IrOpcode::kFloat64RoundDown:
      return MarkAsFloat64(node), VisitFloat64RoundDown(node);
    case IrOpcode::kFloat64RoundTruncate:
      return MarkAsFloat64(node), VisitFloat64RoundTruncate(node);
    case IrOpcode::kFloat64RoundTiesAway:
      return MarkAsFloat64(node), VisitFloat64RoundTiesAway(node);
    case IrOpcode::kFloat64ExtractLowWord32:
      return MarkAsWord32(node), VisitFloat64ExtractLowWord32(node);
    case IrOpcode::kFloat64ExtractHighWord32:
      return MarkAsWord32(node), VisitFloat64ExtractHighWord32(node);
    case IrOpcode::kFloat64InsertLowWord32:
      return MarkAsFloat64(node), VisitFloat64InsertLowWord32(node);
    case IrOpcode::kFloat64InsertHighWord32:
      return MarkAsFloat64(node), VisitFloat64InsertHighWord32(node);
    case IrOpcode::kLoadStackPointer:
      return VisitLoadStackPointer(node);
    case IrOpcode::kCheckedLoad: {
      MachineType rep = OpParameter<MachineType>(node);
      MarkAsRepresentation(rep, node);
      return VisitCheckedLoad(node);
    }
    case IrOpcode::kCheckedStore:
      return VisitCheckedStore(node);
    default:
      V8_Fatal(__FILE__, __LINE__, "Unexpected operator #%d:%s @ node #%d",
               node->opcode(), node->op()->mnemonic(), node->id());
      break;
  }
}


#if V8_TURBOFAN_BACKEND

void InstructionSelector::VisitTruncateFloat64ToInt32(Node* node) {
  OperandGenerator g(this);
  Emit(kArchTruncateDoubleToI, g.DefineAsRegister(node),
       g.UseRegister(node->InputAt(0)));
}


void InstructionSelector::VisitLoadStackPointer(Node* node) {
  OperandGenerator g(this);
  Emit(kArchStackPointer, g.DefineAsRegister(node));
}


void InstructionSelector::EmitTableSwitch(const SwitchInfo& sw,
                                          InstructionOperand& index_operand) {
  OperandGenerator g(this);
  size_t input_count = 2 + sw.value_range;
  auto* inputs = zone()->NewArray<InstructionOperand>(input_count);
  inputs[0] = index_operand;
  InstructionOperand default_operand = g.Label(sw.default_branch);
  std::fill(&inputs[1], &inputs[input_count], default_operand);
  for (size_t index = 0; index < sw.case_count; ++index) {
    size_t value = sw.case_values[index] - sw.min_value;
    BasicBlock* branch = sw.case_branches[index];
    DCHECK_LE(0u, value);
    DCHECK_LT(value + 2, input_count);
    inputs[value + 2] = g.Label(branch);
  }
  Emit(kArchTableSwitch, 0, nullptr, input_count, inputs, 0, nullptr);
}


void InstructionSelector::EmitLookupSwitch(const SwitchInfo& sw,
                                           InstructionOperand& value_operand) {
  OperandGenerator g(this);
  size_t input_count = 2 + sw.case_count * 2;
  auto* inputs = zone()->NewArray<InstructionOperand>(input_count);
  inputs[0] = value_operand;
  inputs[1] = g.Label(sw.default_branch);
  for (size_t index = 0; index < sw.case_count; ++index) {
    int32_t value = sw.case_values[index];
    BasicBlock* branch = sw.case_branches[index];
    inputs[index * 2 + 2 + 0] = g.TempImmediate(value);
    inputs[index * 2 + 2 + 1] = g.Label(branch);
  }
  Emit(kArchLookupSwitch, 0, nullptr, input_count, inputs, 0, nullptr);
}


#endif  // V8_TURBOFAN_BACKEND

// 32 bit targets do not implement the following instructions.
#if V8_TARGET_ARCH_32_BIT && !V8_TARGET_ARCH_X64 && V8_TURBOFAN_BACKEND

void InstructionSelector::VisitWord64And(Node* node) { UNIMPLEMENTED(); }


void InstructionSelector::VisitWord64Or(Node* node) { UNIMPLEMENTED(); }


void InstructionSelector::VisitWord64Xor(Node* node) { UNIMPLEMENTED(); }


void InstructionSelector::VisitWord64Shl(Node* node) { UNIMPLEMENTED(); }


void InstructionSelector::VisitWord64Shr(Node* node) { UNIMPLEMENTED(); }


void InstructionSelector::VisitWord64Sar(Node* node) { UNIMPLEMENTED(); }


void InstructionSelector::VisitWord64Ror(Node* node) { UNIMPLEMENTED(); }


void InstructionSelector::VisitWord64Equal(Node* node) { UNIMPLEMENTED(); }


void InstructionSelector::VisitInt64Add(Node* node) { UNIMPLEMENTED(); }


void InstructionSelector::VisitInt64Sub(Node* node) { UNIMPLEMENTED(); }


void InstructionSelector::VisitInt64Mul(Node* node) { UNIMPLEMENTED(); }


void InstructionSelector::VisitInt64Div(Node* node) { UNIMPLEMENTED(); }


void InstructionSelector::VisitInt64LessThan(Node* node) { UNIMPLEMENTED(); }


void InstructionSelector::VisitInt64LessThanOrEqual(Node* node) {
  UNIMPLEMENTED();
}


void InstructionSelector::VisitUint64Div(Node* node) { UNIMPLEMENTED(); }


void InstructionSelector::VisitInt64Mod(Node* node) { UNIMPLEMENTED(); }


void InstructionSelector::VisitUint64LessThan(Node* node) { UNIMPLEMENTED(); }


void InstructionSelector::VisitUint64Mod(Node* node) { UNIMPLEMENTED(); }


void InstructionSelector::VisitChangeInt32ToInt64(Node* node) {
  UNIMPLEMENTED();
}


void InstructionSelector::VisitChangeUint32ToUint64(Node* node) {
  UNIMPLEMENTED();
}


void InstructionSelector::VisitTruncateInt64ToInt32(Node* node) {
  UNIMPLEMENTED();
}

#endif  // V8_TARGET_ARCH_32_BIT && !V8_TARGET_ARCH_X64 && V8_TURBOFAN_BACKEND


void InstructionSelector::VisitFinish(Node* node) {
  OperandGenerator g(this);
  Node* value = node->InputAt(0);
  Emit(kArchNop, g.DefineSameAsFirst(node), g.Use(value));
}


void InstructionSelector::VisitParameter(Node* node) {
  OperandGenerator g(this);
  int index = ParameterIndexOf(node->op());
  Emit(kArchNop,
       g.DefineAsLocation(node, linkage()->GetParameterLocation(index),
                          linkage()->GetParameterType(index)));
}


void InstructionSelector::VisitIfException(Node* node) {
  OperandGenerator g(this);
  Node* call = node->InputAt(0);
  DCHECK_EQ(IrOpcode::kCall, call->opcode());
  const CallDescriptor* descriptor = OpParameter<const CallDescriptor*>(call);
  Emit(kArchNop, g.DefineAsLocation(node, descriptor->GetReturnLocation(0),
                                    descriptor->GetReturnType(0)));
}


void InstructionSelector::VisitOsrValue(Node* node) {
  OperandGenerator g(this);
  int index = OpParameter<int>(node);
  Emit(kArchNop, g.DefineAsLocation(node, linkage()->GetOsrValueLocation(index),
                                    kMachAnyTagged));
}


void InstructionSelector::VisitPhi(Node* node) {
  const int input_count = node->op()->ValueInputCount();
  PhiInstruction* phi = new (instruction_zone())
      PhiInstruction(instruction_zone(), GetVirtualRegister(node),
                     static_cast<size_t>(input_count));
  sequence()
      ->InstructionBlockAt(RpoNumber::FromInt(current_block_->rpo_number()))
      ->AddPhi(phi);
  for (int i = 0; i < input_count; ++i) {
    Node* const input = node->InputAt(i);
    MarkAsUsed(input);
    phi->SetInput(static_cast<size_t>(i), GetVirtualRegister(input));
  }
}


void InstructionSelector::VisitProjection(Node* node) {
  OperandGenerator g(this);
  Node* value = node->InputAt(0);
  switch (value->opcode()) {
    case IrOpcode::kInt32AddWithOverflow:
    case IrOpcode::kInt32SubWithOverflow:
      if (ProjectionIndexOf(node->op()) == 0u) {
        Emit(kArchNop, g.DefineSameAsFirst(node), g.Use(value));
      } else {
        DCHECK(ProjectionIndexOf(node->op()) == 1u);
        MarkAsUsed(value);
      }
      break;
    default:
      break;
  }
}


void InstructionSelector::VisitConstant(Node* node) {
  // We must emit a NOP here because every live range needs a defining
  // instruction in the register allocator.
  OperandGenerator g(this);
  Emit(kArchNop, g.DefineAsConstant(node));
}


void InstructionSelector::VisitGoto(BasicBlock* target) {
  // jump to the next block.
  OperandGenerator g(this);
  Emit(kArchJmp, g.NoOutput(), g.Label(target));
}


void InstructionSelector::VisitReturn(Node* value) {
  DCHECK_NOT_NULL(value);
  OperandGenerator g(this);
  Emit(kArchRet, g.NoOutput(),
       g.UseLocation(value, linkage()->GetReturnLocation(),
                     linkage()->GetReturnType()));
}


void InstructionSelector::VisitDeoptimize(Node* value) {
  OperandGenerator g(this);

  FrameStateDescriptor* desc = GetFrameStateDescriptor(value);
  size_t arg_count = desc->GetTotalSize() + 1;  // Include deopt id.

  InstructionOperandVector args(instruction_zone());
  args.reserve(arg_count);

  InstructionSequence::StateId state_id =
      sequence()->AddFrameStateDescriptor(desc);
  args.push_back(g.TempImmediate(state_id.ToInt()));

  AddFrameStateInputs(value, &args, desc);

  DCHECK_EQ(args.size(), arg_count);

  Emit(kArchDeoptimize, 0, nullptr, arg_count, &args.front(), 0, nullptr);
}


void InstructionSelector::VisitThrow(Node* value) {
  OperandGenerator g(this);
  Emit(kArchNop, g.NoOutput());  // TODO(titzer)
}


FrameStateDescriptor* InstructionSelector::GetFrameStateDescriptor(
    Node* state) {
  DCHECK(state->opcode() == IrOpcode::kFrameState);
  DCHECK_EQ(5, state->InputCount());
  DCHECK_EQ(IrOpcode::kTypedStateValues, state->InputAt(0)->opcode());
  DCHECK_EQ(IrOpcode::kTypedStateValues, state->InputAt(1)->opcode());
  DCHECK_EQ(IrOpcode::kTypedStateValues, state->InputAt(2)->opcode());
  FrameStateCallInfo state_info = OpParameter<FrameStateCallInfo>(state);

  int parameters =
      static_cast<int>(StateValuesAccess(state->InputAt(0)).size());
  int locals = static_cast<int>(StateValuesAccess(state->InputAt(1)).size());
  int stack = static_cast<int>(StateValuesAccess(state->InputAt(2)).size());

  FrameStateDescriptor* outer_state = NULL;
  Node* outer_node = state->InputAt(4);
  if (outer_node->opcode() == IrOpcode::kFrameState) {
    outer_state = GetFrameStateDescriptor(outer_node);
  }

  return new (instruction_zone()) FrameStateDescriptor(
      instruction_zone(), state_info, parameters, locals, stack, outer_state);
}


static InstructionOperand SlotOrImmediate(OperandGenerator* g, Node* input) {
  switch (input->opcode()) {
    case IrOpcode::kInt32Constant:
    case IrOpcode::kNumberConstant:
    case IrOpcode::kFloat64Constant:
    case IrOpcode::kHeapConstant:
      return g->UseImmediate(input);
    default:
      return g->UseUniqueSlot(input);
  }
}


void InstructionSelector::AddFrameStateInputs(
    Node* state, InstructionOperandVector* inputs,
    FrameStateDescriptor* descriptor) {
  DCHECK_EQ(IrOpcode::kFrameState, state->op()->opcode());

  if (descriptor->outer_state() != NULL) {
    AddFrameStateInputs(state->InputAt(4), inputs, descriptor->outer_state());
  }

  Node* parameters = state->InputAt(0);
  Node* locals = state->InputAt(1);
  Node* stack = state->InputAt(2);
  Node* context = state->InputAt(3);

  DCHECK_EQ(IrOpcode::kTypedStateValues, parameters->op()->opcode());
  DCHECK_EQ(IrOpcode::kTypedStateValues, locals->op()->opcode());
  DCHECK_EQ(IrOpcode::kTypedStateValues, stack->op()->opcode());

  DCHECK_EQ(descriptor->parameters_count(),
            StateValuesAccess(parameters).size());
  DCHECK_EQ(descriptor->locals_count(), StateValuesAccess(locals).size());
  DCHECK_EQ(descriptor->stack_count(), StateValuesAccess(stack).size());

  ZoneVector<MachineType> types(instruction_zone());
  types.reserve(descriptor->GetSize());

  OperandGenerator g(this);
  size_t value_index = 0;
  for (StateValuesAccess::TypedNode input_node :
       StateValuesAccess(parameters)) {
    inputs->push_back(SlotOrImmediate(&g, input_node.node));
    descriptor->SetType(value_index++, input_node.type);
  }
  if (descriptor->HasContext()) {
    inputs->push_back(SlotOrImmediate(&g, context));
    descriptor->SetType(value_index++, kMachAnyTagged);
  }
  for (StateValuesAccess::TypedNode input_node : StateValuesAccess(locals)) {
    inputs->push_back(SlotOrImmediate(&g, input_node.node));
    descriptor->SetType(value_index++, input_node.type);
  }
  for (StateValuesAccess::TypedNode input_node : StateValuesAccess(stack)) {
    inputs->push_back(SlotOrImmediate(&g, input_node.node));
    descriptor->SetType(value_index++, input_node.type);
  }
  DCHECK(value_index == descriptor->GetSize());
}


#if !V8_TURBOFAN_BACKEND

#define DECLARE_UNIMPLEMENTED_SELECTOR(x) \
  void InstructionSelector::Visit##x(Node* node) { UNIMPLEMENTED(); }
MACHINE_OP_LIST(DECLARE_UNIMPLEMENTED_SELECTOR)
#undef DECLARE_UNIMPLEMENTED_SELECTOR


void InstructionSelector::VisitCall(Node* node, BasicBlock* handler) {
  UNIMPLEMENTED();
}


void InstructionSelector::VisitTailCall(Node* node) { UNIMPLEMENTED(); }


void InstructionSelector::VisitBranch(Node* branch, BasicBlock* tbranch,
                                      BasicBlock* fbranch) {
  UNIMPLEMENTED();
}


void InstructionSelector::VisitSwitch(Node* node, const SwitchInfo& sw) {
  UNIMPLEMENTED();
}


// static
MachineOperatorBuilder::Flags
InstructionSelector::SupportedMachineOperatorFlags() {
  return MachineOperatorBuilder::Flag::kNoFlags;
}

#endif  // !V8_TURBOFAN_BACKEND

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