src/compiler/mips64/instruction-selector-mips64.cc

// 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/base/adapters.h"
#include "src/base/bits.h"
#include "src/compiler/instruction-selector-impl.h"
#include "src/compiler/node-matchers.h"
#include "src/compiler/node-properties.h"

namespace v8 {
namespace internal {
namespace compiler {

#define TRACE_UNIMPL() \
  PrintF("UNIMPLEMENTED instr_sel: %s at line %d\n", __FUNCTION__, __LINE__)

#define TRACE() PrintF("instr_sel: %s at line %d\n", __FUNCTION__, __LINE__)


// Adds Mips-specific methods for generating InstructionOperands.
class Mips64OperandGenerator final : public OperandGenerator {
 public:
  explicit Mips64OperandGenerator(InstructionSelector* selector)
      : OperandGenerator(selector) {}

  InstructionOperand UseOperand(Node* node, InstructionCode opcode) {
    if (CanBeImmediate(node, opcode)) {
      return UseImmediate(node);
    }
    return UseRegister(node);
  }

  bool CanBeImmediate(Node* node, InstructionCode opcode) {
    int64_t value;
    if (node->opcode() == IrOpcode::kInt32Constant)
      value = OpParameter<int32_t>(node);
    else if (node->opcode() == IrOpcode::kInt64Constant)
      value = OpParameter<int64_t>(node);
    else
      return false;
    switch (ArchOpcodeField::decode(opcode)) {
      case kMips64Shl:
      case kMips64Sar:
      case kMips64Shr:
        return is_uint5(value);
      case kMips64Dshl:
      case kMips64Dsar:
      case kMips64Dshr:
        return is_uint6(value);
      case kMips64Xor:
        return is_uint16(value);
      case kMips64Ldc1:
      case kMips64Sdc1:
        return is_int16(value + kIntSize);
      default:
        return is_int16(value);
    }
  }

 private:
  bool ImmediateFitsAddrMode1Instruction(int32_t imm) const {
    TRACE_UNIMPL();
    return false;
  }
};


static void VisitRR(InstructionSelector* selector, ArchOpcode opcode,
                    Node* node) {
  Mips64OperandGenerator g(selector);
  selector->Emit(opcode, g.DefineAsRegister(node),
                 g.UseRegister(node->InputAt(0)));
}


static void VisitRRR(InstructionSelector* selector, ArchOpcode opcode,
                     Node* node) {
  Mips64OperandGenerator g(selector);
  selector->Emit(opcode, g.DefineAsRegister(node),
                 g.UseRegister(node->InputAt(0)),
                 g.UseRegister(node->InputAt(1)));
}


static void VisitRRO(InstructionSelector* selector, ArchOpcode opcode,
                     Node* node) {
  Mips64OperandGenerator g(selector);
  selector->Emit(opcode, g.DefineAsRegister(node),
                 g.UseRegister(node->InputAt(0)),
                 g.UseOperand(node->InputAt(1), opcode));
}


static void VisitBinop(InstructionSelector* selector, Node* node,
                       InstructionCode opcode, FlagsContinuation* cont) {
  Mips64OperandGenerator g(selector);
  Int32BinopMatcher m(node);
  InstructionOperand inputs[4];
  size_t input_count = 0;
  InstructionOperand outputs[2];
  size_t output_count = 0;

  inputs[input_count++] = g.UseRegister(m.left().node());
  inputs[input_count++] = g.UseOperand(m.right().node(), opcode);

  if (cont->IsBranch()) {
    inputs[input_count++] = g.Label(cont->true_block());
    inputs[input_count++] = g.Label(cont->false_block());
  }

  outputs[output_count++] = g.DefineAsRegister(node);
  if (cont->IsSet()) {
    outputs[output_count++] = g.DefineAsRegister(cont->result());
  }

  DCHECK_NE(0u, input_count);
  DCHECK_NE(0u, output_count);
  DCHECK_GE(arraysize(inputs), input_count);
  DCHECK_GE(arraysize(outputs), output_count);

  selector->Emit(cont->Encode(opcode), output_count, outputs, input_count,
                 inputs);
}


static void VisitBinop(InstructionSelector* selector, Node* node,
                       InstructionCode opcode) {
  FlagsContinuation cont;
  VisitBinop(selector, node, opcode, &cont);
}


void InstructionSelector::VisitLoad(Node* node) {
  MachineType rep = RepresentationOf(OpParameter<LoadRepresentation>(node));
  MachineType typ = TypeOf(OpParameter<LoadRepresentation>(node));
  Mips64OperandGenerator g(this);
  Node* base = node->InputAt(0);
  Node* index = node->InputAt(1);

  ArchOpcode opcode;
  switch (rep) {
    case kRepFloat32:
      opcode = kMips64Lwc1;
      break;
    case kRepFloat64:
      opcode = kMips64Ldc1;
      break;
    case kRepBit:  // Fall through.
    case kRepWord8:
      opcode = typ == kTypeUint32 ? kMips64Lbu : kMips64Lb;
      break;
    case kRepWord16:
      opcode = typ == kTypeUint32 ? kMips64Lhu : kMips64Lh;
      break;
    case kRepWord32:
      opcode = kMips64Lw;
      break;
    case kRepTagged:  // Fall through.
    case kRepWord64:
      opcode = kMips64Ld;
      break;
    default:
      UNREACHABLE();
      return;
  }

  if (g.CanBeImmediate(index, opcode)) {
    Emit(opcode | AddressingModeField::encode(kMode_MRI),
         g.DefineAsRegister(node), g.UseRegister(base), g.UseImmediate(index));
  } else {
    InstructionOperand addr_reg = g.TempRegister();
    Emit(kMips64Dadd | AddressingModeField::encode(kMode_None), addr_reg,
         g.UseRegister(index), g.UseRegister(base));
    // Emit desired load opcode, using temp addr_reg.
    Emit(opcode | AddressingModeField::encode(kMode_MRI),
         g.DefineAsRegister(node), addr_reg, g.TempImmediate(0));
  }
}


void InstructionSelector::VisitStore(Node* node) {
  Mips64OperandGenerator g(this);
  Node* base = node->InputAt(0);
  Node* index = node->InputAt(1);
  Node* value = node->InputAt(2);

  StoreRepresentation store_rep = OpParameter<StoreRepresentation>(node);
  MachineType rep = RepresentationOf(store_rep.machine_type());
  if (store_rep.write_barrier_kind() == kFullWriteBarrier) {
    DCHECK(rep == kRepTagged);
    // TODO(dcarney): refactor RecordWrite function to take temp registers
    //                and pass them here instead of using fixed regs
    // TODO(dcarney): handle immediate indices.
    InstructionOperand temps[] = {g.TempRegister(t1), g.TempRegister(t2)};
    Emit(kMips64StoreWriteBarrier, g.NoOutput(), g.UseFixed(base, t0),
         g.UseFixed(index, t1), g.UseFixed(value, t2), arraysize(temps), temps);
    return;
  }
  DCHECK_EQ(kNoWriteBarrier, store_rep.write_barrier_kind());

  ArchOpcode opcode;
  switch (rep) {
    case kRepFloat32:
      opcode = kMips64Swc1;
      break;
    case kRepFloat64:
      opcode = kMips64Sdc1;
      break;
    case kRepBit:  // Fall through.
    case kRepWord8:
      opcode = kMips64Sb;
      break;
    case kRepWord16:
      opcode = kMips64Sh;
      break;
    case kRepWord32:
      opcode = kMips64Sw;
      break;
    case kRepTagged:  // Fall through.
    case kRepWord64:
      opcode = kMips64Sd;
      break;
    default:
      UNREACHABLE();
      return;
  }

  if (g.CanBeImmediate(index, opcode)) {
    Emit(opcode | AddressingModeField::encode(kMode_MRI), g.NoOutput(),
         g.UseRegister(base), g.UseImmediate(index), g.UseRegister(value));
  } else {
    InstructionOperand addr_reg = g.TempRegister();
    Emit(kMips64Dadd | AddressingModeField::encode(kMode_None), addr_reg,
         g.UseRegister(index), g.UseRegister(base));
    // Emit desired store opcode, using temp addr_reg.
    Emit(opcode | AddressingModeField::encode(kMode_MRI), g.NoOutput(),
         addr_reg, g.TempImmediate(0), g.UseRegister(value));
  }
}


void InstructionSelector::VisitWord32And(Node* node) {
  VisitBinop(this, node, kMips64And);
}


void InstructionSelector::VisitWord64And(Node* node) {
  VisitBinop(this, node, kMips64And);
}


void InstructionSelector::VisitWord32Or(Node* node) {
  VisitBinop(this, node, kMips64Or);
}


void InstructionSelector::VisitWord64Or(Node* node) {
  VisitBinop(this, node, kMips64Or);
}


void InstructionSelector::VisitWord32Xor(Node* node) {
  VisitBinop(this, node, kMips64Xor);
}


void InstructionSelector::VisitWord64Xor(Node* node) {
  VisitBinop(this, node, kMips64Xor);
}


void InstructionSelector::VisitWord32Shl(Node* node) {
  VisitRRO(this, kMips64Shl, node);
}


void InstructionSelector::VisitWord32Shr(Node* node) {
  VisitRRO(this, kMips64Shr, node);
}


void InstructionSelector::VisitWord32Sar(Node* node) {
  VisitRRO(this, kMips64Sar, node);
}


void InstructionSelector::VisitWord64Shl(Node* node) {
  VisitRRO(this, kMips64Dshl, node);
}


void InstructionSelector::VisitWord64Shr(Node* node) {
  VisitRRO(this, kMips64Dshr, node);
}


void InstructionSelector::VisitWord64Sar(Node* node) {
  VisitRRO(this, kMips64Dsar, node);
}


void InstructionSelector::VisitWord32Ror(Node* node) {
  VisitRRO(this, kMips64Ror, node);
}


void InstructionSelector::VisitWord32Clz(Node* node) {
  VisitRR(this, kMips64Clz, node);
}


void InstructionSelector::VisitWord64Ror(Node* node) {
  VisitRRO(this, kMips64Dror, node);
}


void InstructionSelector::VisitInt32Add(Node* node) {
  Mips64OperandGenerator g(this);
  // TODO(plind): Consider multiply & add optimization from arm port.
  VisitBinop(this, node, kMips64Add);
}


void InstructionSelector::VisitInt64Add(Node* node) {
  Mips64OperandGenerator g(this);
  // TODO(plind): Consider multiply & add optimization from arm port.
  VisitBinop(this, node, kMips64Dadd);
}


void InstructionSelector::VisitInt32Sub(Node* node) {
  VisitBinop(this, node, kMips64Sub);
}


void InstructionSelector::VisitInt64Sub(Node* node) {
  VisitBinop(this, node, kMips64Dsub);
}


void InstructionSelector::VisitInt32Mul(Node* node) {
  Mips64OperandGenerator g(this);
  Int32BinopMatcher m(node);
  if (m.right().HasValue() && m.right().Value() > 0) {
    int32_t value = m.right().Value();
    if (base::bits::IsPowerOfTwo32(value)) {
      Emit(kMips64Shl | AddressingModeField::encode(kMode_None),
           g.DefineAsRegister(node), g.UseRegister(m.left().node()),
           g.TempImmediate(WhichPowerOf2(value)));
      return;
    }
    if (base::bits::IsPowerOfTwo32(value - 1)) {
      InstructionOperand temp = g.TempRegister();
      Emit(kMips64Shl | AddressingModeField::encode(kMode_None), temp,
           g.UseRegister(m.left().node()),
           g.TempImmediate(WhichPowerOf2(value - 1)));
      Emit(kMips64Add | AddressingModeField::encode(kMode_None),
           g.DefineAsRegister(node), g.UseRegister(m.left().node()), temp);
      return;
    }
    if (base::bits::IsPowerOfTwo32(value + 1)) {
      InstructionOperand temp = g.TempRegister();
      Emit(kMips64Shl | AddressingModeField::encode(kMode_None), temp,
           g.UseRegister(m.left().node()),
           g.TempImmediate(WhichPowerOf2(value + 1)));
      Emit(kMips64Sub | AddressingModeField::encode(kMode_None),
           g.DefineAsRegister(node), temp, g.UseRegister(m.left().node()));
      return;
    }
  }
  VisitRRR(this, kMips64Mul, node);
}


void InstructionSelector::VisitInt32MulHigh(Node* node) {
  VisitRRR(this, kMips64MulHigh, node);
}


void InstructionSelector::VisitUint32MulHigh(Node* node) {
  Mips64OperandGenerator g(this);
  InstructionOperand const dmul_operand = g.TempRegister();
  Emit(kMips64MulHighU, dmul_operand, g.UseRegister(node->InputAt(0)),
       g.UseRegister(node->InputAt(1)));
  Emit(kMips64Ext, g.DefineAsRegister(node), dmul_operand, g.TempImmediate(0),
       g.TempImmediate(32));
}


void InstructionSelector::VisitInt64Mul(Node* node) {
  Mips64OperandGenerator g(this);
  Int64BinopMatcher m(node);
  // TODO(dusmil): Add optimization for shifts larger than 32.
  if (m.right().HasValue() && m.right().Value() > 0) {
    int32_t value = static_cast<int32_t>(m.right().Value());
    if (base::bits::IsPowerOfTwo32(value)) {
      Emit(kMips64Dshl | AddressingModeField::encode(kMode_None),
           g.DefineAsRegister(node), g.UseRegister(m.left().node()),
           g.TempImmediate(WhichPowerOf2(value)));
      return;
    }
    if (base::bits::IsPowerOfTwo32(value - 1)) {
      InstructionOperand temp = g.TempRegister();
      Emit(kMips64Dshl | AddressingModeField::encode(kMode_None), temp,
           g.UseRegister(m.left().node()),
           g.TempImmediate(WhichPowerOf2(value - 1)));
      Emit(kMips64Dadd | AddressingModeField::encode(kMode_None),
           g.DefineAsRegister(node), g.UseRegister(m.left().node()), temp);
      return;
    }
    if (base::bits::IsPowerOfTwo32(value + 1)) {
      InstructionOperand temp = g.TempRegister();
      Emit(kMips64Dshl | AddressingModeField::encode(kMode_None), temp,
           g.UseRegister(m.left().node()),
           g.TempImmediate(WhichPowerOf2(value + 1)));
      Emit(kMips64Dsub | AddressingModeField::encode(kMode_None),
           g.DefineAsRegister(node), temp, g.UseRegister(m.left().node()));
      return;
    }
  }
  Emit(kMips64Dmul, g.DefineAsRegister(node), g.UseRegister(m.left().node()),
       g.UseRegister(m.right().node()));
}


void InstructionSelector::VisitInt32Div(Node* node) {
  Mips64OperandGenerator g(this);
  Int32BinopMatcher m(node);
  Emit(kMips64Div, g.DefineAsRegister(node), g.UseRegister(m.left().node()),
       g.UseRegister(m.right().node()));
}


void InstructionSelector::VisitUint32Div(Node* node) {
  Mips64OperandGenerator g(this);
  Int32BinopMatcher m(node);
  Emit(kMips64DivU, g.DefineAsRegister(node), g.UseRegister(m.left().node()),
       g.UseRegister(m.right().node()));
}


void InstructionSelector::VisitInt32Mod(Node* node) {
  Mips64OperandGenerator g(this);
  Int32BinopMatcher m(node);
  Emit(kMips64Mod, g.DefineAsRegister(node), g.UseRegister(m.left().node()),
       g.UseRegister(m.right().node()));
}


void InstructionSelector::VisitUint32Mod(Node* node) {
  Mips64OperandGenerator g(this);
  Int32BinopMatcher m(node);
  Emit(kMips64ModU, g.DefineAsRegister(node), g.UseRegister(m.left().node()),
       g.UseRegister(m.right().node()));
}


void InstructionSelector::VisitInt64Div(Node* node) {
  Mips64OperandGenerator g(this);
  Int64BinopMatcher m(node);
  Emit(kMips64Ddiv, g.DefineAsRegister(node), g.UseRegister(m.left().node()),
       g.UseRegister(m.right().node()));
}


void InstructionSelector::VisitUint64Div(Node* node) {
  Mips64OperandGenerator g(this);
  Int64BinopMatcher m(node);
  Emit(kMips64DdivU, g.DefineAsRegister(node), g.UseRegister(m.left().node()),
       g.UseRegister(m.right().node()));
}


void InstructionSelector::VisitInt64Mod(Node* node) {
  Mips64OperandGenerator g(this);
  Int64BinopMatcher m(node);
  Emit(kMips64Dmod, g.DefineAsRegister(node), g.UseRegister(m.left().node()),
       g.UseRegister(m.right().node()));
}


void InstructionSelector::VisitUint64Mod(Node* node) {
  Mips64OperandGenerator g(this);
  Int64BinopMatcher m(node);
  Emit(kMips64DmodU, g.DefineAsRegister(node), g.UseRegister(m.left().node()),
       g.UseRegister(m.right().node()));
}


void InstructionSelector::VisitChangeFloat32ToFloat64(Node* node) {
  VisitRR(this, kMips64CvtDS, node);
}


void InstructionSelector::VisitChangeInt32ToFloat64(Node* node) {
  VisitRR(this, kMips64CvtDW, node);
}


void InstructionSelector::VisitChangeUint32ToFloat64(Node* node) {
  VisitRR(this, kMips64CvtDUw, node);
}


void InstructionSelector::VisitChangeFloat64ToInt32(Node* node) {
  VisitRR(this, kMips64TruncWD, node);
}


void InstructionSelector::VisitChangeFloat64ToUint32(Node* node) {
  VisitRR(this, kMips64TruncUwD, node);
}


void InstructionSelector::VisitChangeInt32ToInt64(Node* node) {
  Mips64OperandGenerator g(this);
  Emit(kMips64Shl, g.DefineAsRegister(node), g.UseRegister(node->InputAt(0)),
       g.TempImmediate(0));
}


void InstructionSelector::VisitChangeUint32ToUint64(Node* node) {
  Mips64OperandGenerator g(this);
  Emit(kMips64Dext, g.DefineAsRegister(node), g.UseRegister(node->InputAt(0)),
       g.TempImmediate(0), g.TempImmediate(32));
}


void InstructionSelector::VisitTruncateInt64ToInt32(Node* node) {
  Mips64OperandGenerator g(this);
  Emit(kMips64Ext, g.DefineAsRegister(node), g.UseRegister(node->InputAt(0)),
       g.TempImmediate(0), g.TempImmediate(32));
}


void InstructionSelector::VisitTruncateFloat64ToFloat32(Node* node) {
  VisitRR(this, kMips64CvtSD, node);
}


void InstructionSelector::VisitTruncateFloat64ToInt32(Node* node) {
  switch (TruncationModeOf(node->op())) {
    case TruncationMode::kJavaScript:
      return VisitRR(this, kArchTruncateDoubleToI, node);
    case TruncationMode::kRoundToZero:
      return VisitRR(this, kMips64TruncWD, node);
  }
  UNREACHABLE();
}


void InstructionSelector::VisitFloat32Add(Node* node) {
  VisitRRR(this, kMips64AddS, node);
}


void InstructionSelector::VisitFloat64Add(Node* node) {
  VisitRRR(this, kMips64AddD, node);
}


void InstructionSelector::VisitFloat32Sub(Node* node) {
  VisitRRR(this, kMips64SubS, node);
}


void InstructionSelector::VisitFloat64Sub(Node* node) {
  Mips64OperandGenerator g(this);
  Float64BinopMatcher m(node);
  if (m.left().IsMinusZero() && m.right().IsFloat64RoundDown() &&
      CanCover(m.node(), m.right().node())) {
    if (m.right().InputAt(0)->opcode() == IrOpcode::kFloat64Sub &&
        CanCover(m.right().node(), m.right().InputAt(0))) {
      Float64BinopMatcher mright0(m.right().InputAt(0));
      if (mright0.left().IsMinusZero()) {
        Emit(kMips64Float64RoundUp, g.DefineAsRegister(node),
             g.UseRegister(mright0.right().node()));
        return;
      }
    }
  }
  VisitRRR(this, kMips64SubD, node);
}


void InstructionSelector::VisitFloat32Mul(Node* node) {
  VisitRRR(this, kMips64MulS, node);
}


void InstructionSelector::VisitFloat64Mul(Node* node) {
  VisitRRR(this, kMips64MulD, node);
}


void InstructionSelector::VisitFloat32Div(Node* node) {
  VisitRRR(this, kMips64DivS, node);
}


void InstructionSelector::VisitFloat64Div(Node* node) {
  VisitRRR(this, kMips64DivD, node);
}


void InstructionSelector::VisitFloat64Mod(Node* node) {
  Mips64OperandGenerator g(this);
  Emit(kMips64ModD, g.DefineAsFixed(node, f0),
       g.UseFixed(node->InputAt(0), f12),
       g.UseFixed(node->InputAt(1), f14))->MarkAsCall();
}


void InstructionSelector::VisitFloat32Max(Node* node) { UNREACHABLE(); }


void InstructionSelector::VisitFloat64Max(Node* node) { UNREACHABLE(); }


void InstructionSelector::VisitFloat32Min(Node* node) { UNREACHABLE(); }


void InstructionSelector::VisitFloat64Min(Node* node) { UNREACHABLE(); }


void InstructionSelector::VisitFloat32Abs(Node* node) {
  VisitRR(this, kMips64AbsS, node);
}


void InstructionSelector::VisitFloat64Abs(Node* node) {
  VisitRR(this, kMips64AbsD, node);
}


void InstructionSelector::VisitFloat32Sqrt(Node* node) {
  VisitRR(this, kMips64SqrtS, node);
}


void InstructionSelector::VisitFloat64Sqrt(Node* node) {
  VisitRR(this, kMips64SqrtD, node);
}


void InstructionSelector::VisitFloat64RoundDown(Node* node) {
  VisitRR(this, kMips64Float64RoundDown, node);
}


void InstructionSelector::VisitFloat64RoundTruncate(Node* node) {
  VisitRR(this, kMips64Float64RoundTruncate, node);
}


void InstructionSelector::VisitFloat64RoundTiesAway(Node* node) {
  UNREACHABLE();
}


void InstructionSelector::VisitCall(Node* node, BasicBlock* handler) {
  Mips64OperandGenerator g(this);
  const CallDescriptor* descriptor = OpParameter<const CallDescriptor*>(node);

  FrameStateDescriptor* frame_state_descriptor = nullptr;
  if (descriptor->NeedsFrameState()) {
    frame_state_descriptor = GetFrameStateDescriptor(
        node->InputAt(static_cast<int>(descriptor->InputCount())));
  }

  CallBuffer buffer(zone(), descriptor, frame_state_descriptor);

  // Compute InstructionOperands for inputs and outputs.
  InitializeCallBuffer(node, &buffer, true, true);

  // Prepare for C function call.
  if (descriptor->IsCFunctionCall()) {
    Emit(kArchPrepareCallCFunction |
             MiscField::encode(static_cast<int>(descriptor->CParameterCount())),
         0, nullptr, 0, nullptr);

    // Poke any stack arguments.
    int slot = kCArgSlotCount;
    for (Node* node : buffer.pushed_nodes) {
      Emit(kMips64StoreToStackSlot, g.NoOutput(), g.UseRegister(node),
           g.TempImmediate(slot << kPointerSizeLog2));
      ++slot;
    }
  } else {
    const int32_t push_count = static_cast<int32_t>(buffer.pushed_nodes.size());
    if (push_count > 0) {
      Emit(kMips64StackClaim, g.NoOutput(),
           g.TempImmediate(push_count << kPointerSizeLog2));
    }
    int32_t slot = push_count - 1;
    for (Node* node : base::Reversed(buffer.pushed_nodes)) {
      Emit(kMips64StoreToStackSlot, g.NoOutput(), g.UseRegister(node),
           g.TempImmediate(slot << kPointerSizeLog2));
      slot--;
    }
  }

  // Pass label of exception handler block.
  CallDescriptor::Flags flags = descriptor->flags();
  if (handler) {
    DCHECK_EQ(IrOpcode::kIfException, handler->front()->opcode());
    IfExceptionHint hint = OpParameter<IfExceptionHint>(handler->front());
    if (hint == IfExceptionHint::kLocallyCaught) {
      flags |= CallDescriptor::kHasLocalCatchHandler;
    }
    flags |= CallDescriptor::kHasExceptionHandler;
    buffer.instruction_args.push_back(g.Label(handler));
  }

  // Select the appropriate opcode based on the call type.
  InstructionCode opcode;
  switch (descriptor->kind()) {
    case CallDescriptor::kCallAddress:
      opcode =
          kArchCallCFunction |
          MiscField::encode(static_cast<int>(descriptor->CParameterCount()));
      break;
    case CallDescriptor::kCallCodeObject:
      opcode = kArchCallCodeObject | MiscField::encode(flags);
      break;
    case CallDescriptor::kCallJSFunction:
      opcode = kArchCallJSFunction | MiscField::encode(flags);
      break;
    default:
      UNREACHABLE();
      return;
  }
  opcode |= MiscField::encode(flags);

  // Emit the call instruction.
  size_t const output_count = buffer.outputs.size();
  auto* outputs = output_count ? &buffer.outputs.front() : nullptr;
  Emit(opcode, output_count, outputs, buffer.instruction_args.size(),
       &buffer.instruction_args.front())->MarkAsCall();
}


void InstructionSelector::VisitTailCall(Node* node) {
  Mips64OperandGenerator g(this);
  const CallDescriptor* descriptor = OpParameter<const CallDescriptor*>(node);
  DCHECK_NE(0, descriptor->flags() & CallDescriptor::kSupportsTailCalls);
  DCHECK_EQ(0, descriptor->flags() & CallDescriptor::kPatchableCallSite);
  DCHECK_EQ(0, descriptor->flags() & CallDescriptor::kNeedsNopAfterCall);

  // TODO(turbofan): Relax restriction for stack parameters.
  if (linkage()->GetIncomingDescriptor()->CanTailCall(node)) {
    CallBuffer buffer(zone(), descriptor, nullptr);

    // Compute InstructionOperands for inputs and outputs.
    InitializeCallBuffer(node, &buffer, true, false);

    // Select the appropriate opcode based on the call type.
    InstructionCode opcode;
    switch (descriptor->kind()) {
      case CallDescriptor::kCallCodeObject:
      case CallDescriptor::kInterpreterDispatch:
        opcode = kArchTailCallCodeObject;
        break;
      case CallDescriptor::kCallJSFunction:
        opcode = kArchTailCallJSFunction;
        break;
      default:
        UNREACHABLE();
        return;
    }
    opcode |= MiscField::encode(descriptor->flags());

    // Emit the tailcall instruction.
    Emit(opcode, 0, nullptr, buffer.instruction_args.size(),
         &buffer.instruction_args.front());
  } else {
    FrameStateDescriptor* frame_state_descriptor =
        descriptor->NeedsFrameState()
            ? GetFrameStateDescriptor(
                  node->InputAt(static_cast<int>(descriptor->InputCount())))
            : nullptr;

    CallBuffer buffer(zone(), descriptor, frame_state_descriptor);

    // Compute InstructionOperands for inputs and outputs.
    InitializeCallBuffer(node, &buffer, true, false);

    const int32_t push_count = static_cast<int32_t>(buffer.pushed_nodes.size());
    if (push_count > 0) {
      Emit(kMips64StackClaim, g.NoOutput(),
           g.TempImmediate(push_count << kPointerSizeLog2));
    }
    int slot = push_count - 1;
    for (Node* node : base::Reversed(buffer.pushed_nodes)) {
      Emit(kMips64StoreToStackSlot, g.NoOutput(), g.UseRegister(node),
           g.TempImmediate(slot << kPointerSizeLog2));
      slot--;
    }

    // Select the appropriate opcode based on the call type.
    InstructionCode opcode;
    switch (descriptor->kind()) {
      case CallDescriptor::kCallCodeObject: {
        opcode = kArchCallCodeObject;
        break;
      }
      case CallDescriptor::kCallJSFunction:
        opcode = kArchCallJSFunction;
        break;
      default:
        UNREACHABLE();
        return;
    }
    opcode |= MiscField::encode(descriptor->flags());

    // Emit the call instruction.
    size_t const output_count = buffer.outputs.size();
    auto* outputs = output_count ? &buffer.outputs.front() : nullptr;
    Emit(opcode, output_count, outputs, buffer.instruction_args.size(),
         &buffer.instruction_args.front())->MarkAsCall();
    Emit(kArchRet, 0, nullptr, output_count, outputs);
  }
}


void InstructionSelector::VisitCheckedLoad(Node* node) {
  MachineType rep = RepresentationOf(OpParameter<MachineType>(node));
  MachineType typ = TypeOf(OpParameter<MachineType>(node));
  Mips64OperandGenerator g(this);
  Node* const buffer = node->InputAt(0);
  Node* const offset = node->InputAt(1);
  Node* const length = node->InputAt(2);
  ArchOpcode opcode;
  switch (rep) {
    case kRepWord8:
      opcode = typ == kTypeInt32 ? kCheckedLoadInt8 : kCheckedLoadUint8;
      break;
    case kRepWord16:
      opcode = typ == kTypeInt32 ? kCheckedLoadInt16 : kCheckedLoadUint16;
      break;
    case kRepWord32:
      opcode = kCheckedLoadWord32;
      break;
    case kRepFloat32:
      opcode = kCheckedLoadFloat32;
      break;
    case kRepFloat64:
      opcode = kCheckedLoadFloat64;
      break;
    default:
      UNREACHABLE();
      return;
  }
  InstructionOperand offset_operand = g.CanBeImmediate(offset, opcode)
                                          ? g.UseImmediate(offset)
                                          : g.UseRegister(offset);

  InstructionOperand length_operand = (!g.CanBeImmediate(offset, opcode))
                                          ? g.CanBeImmediate(length, opcode)
                                                ? g.UseImmediate(length)
                                                : g.UseRegister(length)
                                          : g.UseRegister(length);

  Emit(opcode | AddressingModeField::encode(kMode_MRI),
       g.DefineAsRegister(node), offset_operand, length_operand,
       g.UseRegister(buffer));
}


void InstructionSelector::VisitCheckedStore(Node* node) {
  MachineType rep = RepresentationOf(OpParameter<MachineType>(node));
  Mips64OperandGenerator g(this);
  Node* const buffer = node->InputAt(0);
  Node* const offset = node->InputAt(1);
  Node* const length = node->InputAt(2);
  Node* const value = node->InputAt(3);
  ArchOpcode opcode;
  switch (rep) {
    case kRepWord8:
      opcode = kCheckedStoreWord8;
      break;
    case kRepWord16:
      opcode = kCheckedStoreWord16;
      break;
    case kRepWord32:
      opcode = kCheckedStoreWord32;
      break;
    case kRepFloat32:
      opcode = kCheckedStoreFloat32;
      break;
    case kRepFloat64:
      opcode = kCheckedStoreFloat64;
      break;
    default:
      UNREACHABLE();
      return;
  }
  InstructionOperand offset_operand = g.CanBeImmediate(offset, opcode)
                                          ? g.UseImmediate(offset)
                                          : g.UseRegister(offset);

  InstructionOperand length_operand = (!g.CanBeImmediate(offset, opcode))
                                          ? g.CanBeImmediate(length, opcode)
                                                ? g.UseImmediate(length)
                                                : g.UseRegister(length)
                                          : g.UseRegister(length);

  Emit(opcode | AddressingModeField::encode(kMode_MRI), g.NoOutput(),
       offset_operand, length_operand, g.UseRegister(value),
       g.UseRegister(buffer));
}


namespace {

// Shared routine for multiple compare operations.
static void VisitCompare(InstructionSelector* selector, InstructionCode opcode,
                         InstructionOperand left, InstructionOperand right,
                         FlagsContinuation* cont) {
  Mips64OperandGenerator g(selector);
  opcode = cont->Encode(opcode);
  if (cont->IsBranch()) {
    selector->Emit(opcode, g.NoOutput(), left, right,
                   g.Label(cont->true_block()), g.Label(cont->false_block()));
  } else {
    DCHECK(cont->IsSet());
    selector->Emit(opcode, g.DefineAsRegister(cont->result()), left, right);
  }
}


// Shared routine for multiple float32 compare operations.
void VisitFloat32Compare(InstructionSelector* selector, Node* node,
                         FlagsContinuation* cont) {
  Mips64OperandGenerator g(selector);
  Node* left = node->InputAt(0);
  Node* right = node->InputAt(1);
  VisitCompare(selector, kMips64CmpS, g.UseRegister(left), g.UseRegister(right),
               cont);
}


// Shared routine for multiple float64 compare operations.
void VisitFloat64Compare(InstructionSelector* selector, Node* node,
                         FlagsContinuation* cont) {
  Mips64OperandGenerator g(selector);
  Node* left = node->InputAt(0);
  Node* right = node->InputAt(1);
  VisitCompare(selector, kMips64CmpD, g.UseRegister(left), g.UseRegister(right),
               cont);
}


// Shared routine for multiple word compare operations.
void VisitWordCompare(InstructionSelector* selector, Node* node,
                      InstructionCode opcode, FlagsContinuation* cont,
                      bool commutative) {
  Mips64OperandGenerator g(selector);
  Node* left = node->InputAt(0);
  Node* right = node->InputAt(1);

  // Match immediates on left or right side of comparison.
  if (g.CanBeImmediate(right, opcode)) {
    VisitCompare(selector, opcode, g.UseRegister(left), g.UseImmediate(right),
                 cont);
  } else if (g.CanBeImmediate(left, opcode)) {
    if (!commutative) cont->Commute();
    VisitCompare(selector, opcode, g.UseRegister(right), g.UseImmediate(left),
                 cont);
  } else {
    VisitCompare(selector, opcode, g.UseRegister(left), g.UseRegister(right),
                 cont);
  }
}


void VisitWord32Compare(InstructionSelector* selector, Node* node,
                        FlagsContinuation* cont) {
  VisitWordCompare(selector, node, kMips64Cmp, cont, false);
}


void VisitWord64Compare(InstructionSelector* selector, Node* node,
                        FlagsContinuation* cont) {
  VisitWordCompare(selector, node, kMips64Cmp, cont, false);
}

}  // namespace


void EmitWordCompareZero(InstructionSelector* selector, Node* value,
                         FlagsContinuation* cont) {
  Mips64OperandGenerator g(selector);
  InstructionCode opcode = cont->Encode(kMips64Cmp);
  InstructionOperand const value_operand = g.UseRegister(value);
  if (cont->IsBranch()) {
    selector->Emit(opcode, g.NoOutput(), value_operand, g.TempImmediate(0),
                   g.Label(cont->true_block()), g.Label(cont->false_block()));
  } else {
    selector->Emit(opcode, g.DefineAsRegister(cont->result()), value_operand,
                   g.TempImmediate(0));
  }
}


// Shared routine for word comparisons against zero.
void VisitWordCompareZero(InstructionSelector* selector, Node* user,
                          Node* value, FlagsContinuation* cont) {
  while (selector->CanCover(user, value)) {
    switch (value->opcode()) {
      case IrOpcode::kWord32Equal: {
        // Combine with comparisons against 0 by simply inverting the
        // continuation.
        Int32BinopMatcher m(value);
        if (m.right().Is(0)) {
          user = value;
          value = m.left().node();
          cont->Negate();
          continue;
        }
        cont->OverwriteAndNegateIfEqual(kEqual);
        return VisitWord32Compare(selector, value, cont);
      }
      case IrOpcode::kInt32LessThan:
        cont->OverwriteAndNegateIfEqual(kSignedLessThan);
        return VisitWord32Compare(selector, value, cont);
      case IrOpcode::kInt32LessThanOrEqual:
        cont->OverwriteAndNegateIfEqual(kSignedLessThanOrEqual);
        return VisitWord32Compare(selector, value, cont);
      case IrOpcode::kUint32LessThan:
        cont->OverwriteAndNegateIfEqual(kUnsignedLessThan);
        return VisitWord32Compare(selector, value, cont);
      case IrOpcode::kUint32LessThanOrEqual:
        cont->OverwriteAndNegateIfEqual(kUnsignedLessThanOrEqual);
        return VisitWord32Compare(selector, value, cont);
      case IrOpcode::kWord64Equal: {
        // Combine with comparisons against 0 by simply inverting the
        // continuation.
        Int64BinopMatcher m(value);
        if (m.right().Is(0)) {
          user = value;
          value = m.left().node();
          cont->Negate();
          continue;
        }
        cont->OverwriteAndNegateIfEqual(kEqual);
        return VisitWord64Compare(selector, value, cont);
      }
      case IrOpcode::kInt64LessThan:
        cont->OverwriteAndNegateIfEqual(kSignedLessThan);
        return VisitWord64Compare(selector, value, cont);
      case IrOpcode::kInt64LessThanOrEqual:
        cont->OverwriteAndNegateIfEqual(kSignedLessThanOrEqual);
        return VisitWord64Compare(selector, value, cont);
      case IrOpcode::kUint64LessThan:
        cont->OverwriteAndNegateIfEqual(kUnsignedLessThan);
        return VisitWord64Compare(selector, value, cont);
      case IrOpcode::kUint64LessThanOrEqual:
        cont->OverwriteAndNegateIfEqual(kUnsignedLessThanOrEqual);
        return VisitWord64Compare(selector, value, cont);
      case IrOpcode::kFloat32Equal:
        cont->OverwriteAndNegateIfEqual(kEqual);
        return VisitFloat32Compare(selector, value, cont);
      case IrOpcode::kFloat32LessThan:
        cont->OverwriteAndNegateIfEqual(kUnsignedLessThan);
        return VisitFloat32Compare(selector, value, cont);
      case IrOpcode::kFloat32LessThanOrEqual:
        cont->OverwriteAndNegateIfEqual(kUnsignedLessThanOrEqual);
        return VisitFloat32Compare(selector, value, cont);
      case IrOpcode::kFloat64Equal:
        cont->OverwriteAndNegateIfEqual(kEqual);
        return VisitFloat64Compare(selector, value, cont);
      case IrOpcode::kFloat64LessThan:
        cont->OverwriteAndNegateIfEqual(kUnsignedLessThan);
        return VisitFloat64Compare(selector, value, cont);
      case IrOpcode::kFloat64LessThanOrEqual:
        cont->OverwriteAndNegateIfEqual(kUnsignedLessThanOrEqual);
        return VisitFloat64Compare(selector, value, cont);
      case IrOpcode::kProjection:
        // Check if this is the overflow output projection of an
        // <Operation>WithOverflow node.
        if (ProjectionIndexOf(value->op()) == 1u) {
          // We cannot combine the <Operation>WithOverflow with this branch
          // unless the 0th projection (the use of the actual value of the
          // <Operation> is either NULL, which means there's no use of the
          // actual value, or was already defined, which means it is scheduled
          // *AFTER* this branch).
          Node* const node = value->InputAt(0);
          Node* const result = NodeProperties::FindProjection(node, 0);
          if (result == NULL || selector->IsDefined(result)) {
            switch (node->opcode()) {
              case IrOpcode::kInt32AddWithOverflow:
                cont->OverwriteAndNegateIfEqual(kOverflow);
                return VisitBinop(selector, node, kMips64Dadd, cont);
              case IrOpcode::kInt32SubWithOverflow:
                cont->OverwriteAndNegateIfEqual(kOverflow);
                return VisitBinop(selector, node, kMips64Dsub, cont);
              default:
                break;
            }
          }
        }
        break;
      case IrOpcode::kWord32And:
      case IrOpcode::kWord64And:
        return VisitWordCompare(selector, value, kMips64Tst, cont, true);
      default:
        break;
    }
    break;
  }

  // Continuation could not be combined with a compare, emit compare against 0.
  EmitWordCompareZero(selector, value, cont);
}


void InstructionSelector::VisitBranch(Node* branch, BasicBlock* tbranch,
                                      BasicBlock* fbranch) {
  FlagsContinuation cont(kNotEqual, tbranch, fbranch);
  VisitWordCompareZero(this, branch, branch->InputAt(0), &cont);
}


void InstructionSelector::VisitSwitch(Node* node, const SwitchInfo& sw) {
  Mips64OperandGenerator g(this);
  InstructionOperand value_operand = g.UseRegister(node->InputAt(0));

  // Emit either ArchTableSwitch or ArchLookupSwitch.
  size_t table_space_cost = 10 + 2 * sw.value_range;
  size_t table_time_cost = 3;
  size_t lookup_space_cost = 2 + 2 * sw.case_count;
  size_t lookup_time_cost = sw.case_count;
  if (sw.case_count > 0 &&
      table_space_cost + 3 * table_time_cost <=
          lookup_space_cost + 3 * lookup_time_cost &&
      sw.min_value > std::numeric_limits<int32_t>::min()) {
    InstructionOperand index_operand = value_operand;
    if (sw.min_value) {
      index_operand = g.TempRegister();
      Emit(kMips64Sub, index_operand, value_operand,
           g.TempImmediate(sw.min_value));
    }
    // Generate a table lookup.
    return EmitTableSwitch(sw, index_operand);
  }

  // Generate a sequence of conditional jumps.
  return EmitLookupSwitch(sw, value_operand);
}


void InstructionSelector::VisitWord32Equal(Node* const node) {
  FlagsContinuation cont(kEqual, node);
  Int32BinopMatcher m(node);
  if (m.right().Is(0)) {
    return VisitWordCompareZero(this, m.node(), m.left().node(), &cont);
  }

  VisitWord32Compare(this, node, &cont);
}


void InstructionSelector::VisitInt32LessThan(Node* node) {
  FlagsContinuation cont(kSignedLessThan, node);
  VisitWord32Compare(this, node, &cont);
}


void InstructionSelector::VisitInt32LessThanOrEqual(Node* node) {
  FlagsContinuation cont(kSignedLessThanOrEqual, node);
  VisitWord32Compare(this, node, &cont);
}


void InstructionSelector::VisitUint32LessThan(Node* node) {
  FlagsContinuation cont(kUnsignedLessThan, node);
  VisitWord32Compare(this, node, &cont);
}


void InstructionSelector::VisitUint32LessThanOrEqual(Node* node) {
  FlagsContinuation cont(kUnsignedLessThanOrEqual, node);
  VisitWord32Compare(this, node, &cont);
}


void InstructionSelector::VisitInt32AddWithOverflow(Node* node) {
  if (Node* ovf = NodeProperties::FindProjection(node, 1)) {
    FlagsContinuation cont(kOverflow, ovf);
    return VisitBinop(this, node, kMips64Dadd, &cont);
  }
  FlagsContinuation cont;
  VisitBinop(this, node, kMips64Dadd, &cont);
}


void InstructionSelector::VisitInt32SubWithOverflow(Node* node) {
  if (Node* ovf = NodeProperties::FindProjection(node, 1)) {
    FlagsContinuation cont(kOverflow, ovf);
    return VisitBinop(this, node, kMips64Dsub, &cont);
  }
  FlagsContinuation cont;
  VisitBinop(this, node, kMips64Dsub, &cont);
}


void InstructionSelector::VisitWord64Equal(Node* const node) {
  FlagsContinuation cont(kEqual, node);
  Int64BinopMatcher m(node);
  if (m.right().Is(0)) {
    return VisitWordCompareZero(this, m.node(), m.left().node(), &cont);
  }

  VisitWord64Compare(this, node, &cont);
}


void InstructionSelector::VisitInt64LessThan(Node* node) {
  FlagsContinuation cont(kSignedLessThan, node);
  VisitWord64Compare(this, node, &cont);
}


void InstructionSelector::VisitInt64LessThanOrEqual(Node* node) {
  FlagsContinuation cont(kSignedLessThanOrEqual, node);
  VisitWord64Compare(this, node, &cont);
}


void InstructionSelector::VisitUint64LessThan(Node* node) {
  FlagsContinuation cont(kUnsignedLessThan, node);
  VisitWord64Compare(this, node, &cont);
}


void InstructionSelector::VisitUint64LessThanOrEqual(Node* node) {
  FlagsContinuation cont(kUnsignedLessThanOrEqual, node);
  VisitWord64Compare(this, node, &cont);
}


void InstructionSelector::VisitFloat32Equal(Node* node) {
  FlagsContinuation cont(kEqual, node);
  VisitFloat32Compare(this, node, &cont);
}


void InstructionSelector::VisitFloat32LessThan(Node* node) {
  FlagsContinuation cont(kUnsignedLessThan, node);
  VisitFloat32Compare(this, node, &cont);
}


void InstructionSelector::VisitFloat32LessThanOrEqual(Node* node) {
  FlagsContinuation cont(kUnsignedLessThanOrEqual, node);
  VisitFloat32Compare(this, node, &cont);
}


void InstructionSelector::VisitFloat64Equal(Node* node) {
  FlagsContinuation cont(kEqual, node);
  VisitFloat64Compare(this, node, &cont);
}


void InstructionSelector::VisitFloat64LessThan(Node* node) {
  FlagsContinuation cont(kUnsignedLessThan, node);
  VisitFloat64Compare(this, node, &cont);
}


void InstructionSelector::VisitFloat64LessThanOrEqual(Node* node) {
  FlagsContinuation cont(kUnsignedLessThanOrEqual, node);
  VisitFloat64Compare(this, node, &cont);
}


void InstructionSelector::VisitFloat64ExtractLowWord32(Node* node) {
  Mips64OperandGenerator g(this);
  Emit(kMips64Float64ExtractLowWord32, g.DefineAsRegister(node),
       g.UseRegister(node->InputAt(0)));
}


void InstructionSelector::VisitFloat64ExtractHighWord32(Node* node) {
  Mips64OperandGenerator g(this);
  Emit(kMips64Float64ExtractHighWord32, g.DefineAsRegister(node),
       g.UseRegister(node->InputAt(0)));
}


void InstructionSelector::VisitFloat64InsertLowWord32(Node* node) {
  Mips64OperandGenerator g(this);
  Node* left = node->InputAt(0);
  Node* right = node->InputAt(1);
  Emit(kMips64Float64InsertLowWord32, g.DefineSameAsFirst(node),
       g.UseRegister(left), g.UseRegister(right));
}


void InstructionSelector::VisitFloat64InsertHighWord32(Node* node) {
  Mips64OperandGenerator g(this);
  Node* left = node->InputAt(0);
  Node* right = node->InputAt(1);
  Emit(kMips64Float64InsertHighWord32, g.DefineSameAsFirst(node),
       g.UseRegister(left), g.UseRegister(right));
}


// static
MachineOperatorBuilder::Flags
InstructionSelector::SupportedMachineOperatorFlags() {
  return MachineOperatorBuilder::kFloat64RoundDown |
         MachineOperatorBuilder::kFloat64RoundTruncate;
}

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