/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
 * vim: set ts=8 sts=2 et sw=2 tw=80:
 * 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/mips32/CodeGenerator-mips32.h"

#include "mozilla/MathAlgorithms.h"

#include "jit/CodeGenerator.h"
#include "jit/MIR.h"
#include "jit/MIRGraph.h"
#include "js/Conversions.h"
#include "vm/Shape.h"

#include "jit/MacroAssembler-inl.h"
#include "jit/shared/CodeGenerator-shared-inl.h"

using namespace js;
using namespace js::jit;

ValueOperand CodeGeneratorMIPS::ToValue(LInstruction* ins, size_t pos) {
  Register typeReg = ToRegister(ins->getOperand(pos + TYPE_INDEX));
  Register payloadReg = ToRegister(ins->getOperand(pos + PAYLOAD_INDEX));
  return ValueOperand(typeReg, payloadReg);
}

ValueOperand CodeGeneratorMIPS::ToTempValue(LInstruction* ins, size_t pos) {
  Register typeReg = ToRegister(ins->getTemp(pos + TYPE_INDEX));
  Register payloadReg = ToRegister(ins->getTemp(pos + PAYLOAD_INDEX));
  return ValueOperand(typeReg, payloadReg);
}

void CodeGenerator::visitBox(LBox* box) {
  const LDefinition* type = box->getDef(TYPE_INDEX);

  MOZ_ASSERT(!box->getOperand(0)->isConstant());

  // For NUNBOX32, the input operand and the output payload have the same
  // virtual register. All that needs to be written is the type tag for
  // the type definition.
  masm.move32(Imm32(MIRTypeToTag(box->type())), ToRegister(type));
}

void CodeGenerator::visitBoxFloatingPoint(LBoxFloatingPoint* box) {
  const AnyRegister in = ToAnyRegister(box->getOperand(0));
  const ValueOperand out = ToOutValue(box);

  masm.moveValue(TypedOrValueRegister(box->type(), in), out);
}

void CodeGenerator::visitUnbox(LUnbox* unbox) {
  // Note that for unbox, the type and payload indexes are switched on the
  // inputs.
  MUnbox* mir = unbox->mir();
  Register type = ToRegister(unbox->type());

  if (mir->fallible()) {
    bailoutCmp32(Assembler::NotEqual, type, Imm32(MIRTypeToTag(mir->type())),
                 unbox->snapshot());
  }
}

void CodeGeneratorMIPS::splitTagForTest(const ValueOperand& value,
                                        ScratchTagScope& tag) {
  MOZ_ASSERT(value.typeReg() == tag);
}

void CodeGenerator::visitCompareI64(LCompareI64* lir) {
  MCompare* mir = lir->mir();
  MOZ_ASSERT(mir->compareType() == MCompare::Compare_Int64 ||
             mir->compareType() == MCompare::Compare_UInt64);

  const LInt64Allocation lhs = lir->getInt64Operand(LCompareI64::Lhs);
  const LInt64Allocation rhs = lir->getInt64Operand(LCompareI64::Rhs);
  Register64 lhsRegs = ToRegister64(lhs);
  Register output = ToRegister(lir->output());

  bool isSigned = mir->compareType() == MCompare::Compare_Int64;
  Assembler::Condition condition = JSOpToCondition(lir->jsop(), isSigned);

  if (IsConstant(rhs)) {
    Imm64 imm = Imm64(ToInt64(rhs));
    masm.cmp64Set(condition, lhsRegs, imm, output);
  } else {
    Register64 rhsRegs = ToRegister64(rhs);
    masm.cmp64Set(condition, lhsRegs, rhsRegs, output);
  }
}

void CodeGenerator::visitCompareI64AndBranch(LCompareI64AndBranch* lir) {
  MCompare* mir = lir->cmpMir();
  MOZ_ASSERT(mir->compareType() == MCompare::Compare_Int64 ||
             mir->compareType() == MCompare::Compare_UInt64);

  const LInt64Allocation lhs = lir->getInt64Operand(LCompareI64::Lhs);
  const LInt64Allocation rhs = lir->getInt64Operand(LCompareI64::Rhs);
  Register64 lhsRegs = ToRegister64(lhs);

  bool isSigned = mir->compareType() == MCompare::Compare_Int64;
  Assembler::Condition condition = JSOpToCondition(lir->jsop(), isSigned);

  Label* trueLabel = getJumpLabelForBranch(lir->ifTrue());
  Label* falseLabel = getJumpLabelForBranch(lir->ifFalse());

  if (isNextBlock(lir->ifFalse()->lir())) {
    falseLabel = nullptr;
  } else if (isNextBlock(lir->ifTrue()->lir())) {
    condition = Assembler::InvertCondition(condition);
    trueLabel = falseLabel;
    falseLabel = nullptr;
  }

  if (IsConstant(rhs)) {
    Imm64 imm = Imm64(ToInt64(rhs));
    masm.branch64(condition, lhsRegs, imm, trueLabel, falseLabel);
  } else {
    Register64 rhsRegs = ToRegister64(rhs);
    masm.branch64(condition, lhsRegs, rhsRegs, trueLabel, falseLabel);
  }
}

void CodeGenerator::visitDivOrModI64(LDivOrModI64* lir) {
  Register64 lhs = ToRegister64(lir->getInt64Operand(LDivOrModI64::Lhs));
  Register64 rhs = ToRegister64(lir->getInt64Operand(LDivOrModI64::Rhs));
  Register64 output = ToOutRegister64(lir);

  MOZ_ASSERT(output == ReturnReg64);

  Label done;

  // Handle divide by zero.
  if (lir->canBeDivideByZero()) {
    Label nonZero;
    masm.branchTest64(Assembler::NonZero, rhs, rhs, InvalidReg, &nonZero);
    masm.wasmTrap(wasm::Trap::IntegerDivideByZero, lir->bytecodeOffset());
    masm.bind(&nonZero);
  }

  // Handle an integer overflow exception from INT64_MIN / -1.
  if (lir->canBeNegativeOverflow()) {
    Label notOverflow;
    masm.branch64(Assembler::NotEqual, lhs, Imm64(INT64_MIN), &notOverflow);
    masm.branch64(Assembler::NotEqual, rhs, Imm64(-1), &notOverflow);
    if (lir->mir()->isMod()) {
      masm.xor64(output, output);
    } else {
      masm.wasmTrap(wasm::Trap::IntegerOverflow, lir->bytecodeOffset());
    }
    masm.jump(&done);
    masm.bind(&notOverflow);
  }

  masm.setupWasmABICall();
  masm.passABIArg(lhs.high);
  masm.passABIArg(lhs.low);
  masm.passABIArg(rhs.high);
  masm.passABIArg(rhs.low);

  MOZ_ASSERT(gen->compilingWasm());
  if (lir->mir()->isMod()) {
    masm.callWithABI(lir->bytecodeOffset(), wasm::SymbolicAddress::ModI64);
  } else {
    masm.callWithABI(lir->bytecodeOffset(), wasm::SymbolicAddress::DivI64);
  }
  MOZ_ASSERT(ReturnReg64 == output);

  masm.bind(&done);
}

void CodeGenerator::visitUDivOrModI64(LUDivOrModI64* lir) {
  Register64 lhs = ToRegister64(lir->getInt64Operand(LDivOrModI64::Lhs));
  Register64 rhs = ToRegister64(lir->getInt64Operand(LDivOrModI64::Rhs));

  MOZ_ASSERT(ToOutRegister64(lir) == ReturnReg64);

  // Prevent divide by zero.
  if (lir->canBeDivideByZero()) {
    Label nonZero;
    masm.branchTest64(Assembler::NonZero, rhs, rhs, InvalidReg, &nonZero);
    masm.wasmTrap(wasm::Trap::IntegerDivideByZero, lir->bytecodeOffset());
    masm.bind(&nonZero);
  }

  masm.setupWasmABICall();
  masm.passABIArg(lhs.high);
  masm.passABIArg(lhs.low);
  masm.passABIArg(rhs.high);
  masm.passABIArg(rhs.low);

  MOZ_ASSERT(gen->compilingWasm());
  if (lir->mir()->isMod()) {
    masm.callWithABI(lir->bytecodeOffset(), wasm::SymbolicAddress::UModI64);
  } else {
    masm.callWithABI(lir->bytecodeOffset(), wasm::SymbolicAddress::UDivI64);
  }
}

void CodeGeneratorMIPS::emitBigIntDiv(LBigIntDiv* ins, Register dividend,
                                      Register divisor, Register output,
                                      Label* fail) {
  // Callers handle division by zero and integer overflow.

#ifdef MIPSR6
  masm.as_div(/* result= */ dividend, dividend, divisor);
#else
  masm.as_div(dividend, divisor);
  masm.as_mflo(dividend);
#endif

  // Create and return the result.
  masm.newGCBigInt(output, divisor, initialBigIntHeap(), fail);
  masm.initializeBigInt(output, dividend);
}

void CodeGeneratorMIPS::emitBigIntMod(LBigIntMod* ins, Register dividend,
                                      Register divisor, Register output,
                                      Label* fail) {
  // Callers handle division by zero and integer overflow.

#ifdef MIPSR6
  masm.as_mod(/* result= */ dividend, dividend, divisor);
#else
  masm.as_div(dividend, divisor);
  masm.as_mfhi(dividend);
#endif

  // Create and return the result.
  masm.newGCBigInt(output, divisor, initialBigIntHeap(), fail);
  masm.initializeBigInt(output, dividend);
}

template <typename T>
void CodeGeneratorMIPS::emitWasmLoadI64(T* lir) {
  const MWasmLoad* mir = lir->mir();

  Register ptrScratch = InvalidReg;
  if (!lir->ptrCopy()->isBogusTemp()) {
    ptrScratch = ToRegister(lir->ptrCopy());
  }

  if (IsUnaligned(mir->access())) {
    masm.wasmUnalignedLoadI64(mir->access(), HeapReg, ToRegister(lir->ptr()),
                              ptrScratch, ToOutRegister64(lir),
                              ToRegister(lir->getTemp(1)));
  } else {
    masm.wasmLoadI64(mir->access(), HeapReg, ToRegister(lir->ptr()), ptrScratch,
                     ToOutRegister64(lir));
  }
}

void CodeGenerator::visitWasmLoadI64(LWasmLoadI64* lir) {
  emitWasmLoadI64(lir);
}

void CodeGenerator::visitWasmUnalignedLoadI64(LWasmUnalignedLoadI64* lir) {
  emitWasmLoadI64(lir);
}

template <typename T>
void CodeGeneratorMIPS::emitWasmStoreI64(T* lir) {
  const MWasmStore* mir = lir->mir();

  Register ptrScratch = InvalidReg;
  if (!lir->ptrCopy()->isBogusTemp()) {
    ptrScratch = ToRegister(lir->ptrCopy());
  }

  if (IsUnaligned(mir->access())) {
    masm.wasmUnalignedStoreI64(mir->access(), ToRegister64(lir->value()),
                               HeapReg, ToRegister(lir->ptr()), ptrScratch,
                               ToRegister(lir->getTemp(1)));
  } else {
    masm.wasmStoreI64(mir->access(), ToRegister64(lir->value()), HeapReg,
                      ToRegister(lir->ptr()), ptrScratch);
  }
}

void CodeGenerator::visitWasmStoreI64(LWasmStoreI64* lir) {
  emitWasmStoreI64(lir);
}

void CodeGenerator::visitWasmUnalignedStoreI64(LWasmUnalignedStoreI64* lir) {
  emitWasmStoreI64(lir);
}

void CodeGenerator::visitWasmSelectI64(LWasmSelectI64* lir) {
  MOZ_ASSERT(lir->mir()->type() == MIRType::Int64);
  Register cond = ToRegister(lir->condExpr());
  const LInt64Allocation trueExpr = lir->trueExpr();
  const LInt64Allocation falseExpr = lir->falseExpr();

  Register64 output = ToOutRegister64(lir);

  masm.move64(ToRegister64(trueExpr), output);

  if (falseExpr.low().isRegister()) {
    masm.as_movz(output.low, ToRegister(falseExpr.low()), cond);
    masm.as_movz(output.high, ToRegister(falseExpr.high()), cond);
  } else {
    Label done;
    masm.ma_b(cond, cond, &done, Assembler::NonZero, ShortJump);
    masm.loadPtr(ToAddress(falseExpr.low()), output.low);
    masm.loadPtr(ToAddress(falseExpr.high()), output.high);
    masm.bind(&done);
  }
}

void CodeGenerator::visitWasmReinterpretFromI64(LWasmReinterpretFromI64* lir) {
  MOZ_ASSERT(lir->mir()->type() == MIRType::Double);
  MOZ_ASSERT(lir->mir()->input()->type() == MIRType::Int64);
  Register64 input = ToRegister64(lir->getInt64Operand(0));
  FloatRegister output = ToFloatRegister(lir->output());

  masm.moveToDoubleLo(input.low, output);
  masm.moveToDoubleHi(input.high, output);
}

void CodeGenerator::visitWasmReinterpretToI64(LWasmReinterpretToI64* lir) {
  MOZ_ASSERT(lir->mir()->type() == MIRType::Int64);
  MOZ_ASSERT(lir->mir()->input()->type() == MIRType::Double);
  FloatRegister input = ToFloatRegister(lir->getOperand(0));
  Register64 output = ToOutRegister64(lir);

  masm.moveFromDoubleLo(input, output.low);
  masm.moveFromDoubleHi(input, output.high);
}

void CodeGenerator::visitExtendInt32ToInt64(LExtendInt32ToInt64* lir) {
  Register input = ToRegister(lir->input());
  Register64 output = ToOutRegister64(lir);

  if (input != output.low) {
    masm.move32(input, output.low);
  }
  if (lir->mir()->isUnsigned()) {
    masm.move32(Imm32(0), output.high);
  } else {
    masm.ma_sra(output.high, output.low, Imm32(31));
  }
}

void CodeGenerator::visitWrapInt64ToInt32(LWrapInt64ToInt32* lir) {
  const LInt64Allocation& input = lir->getInt64Operand(0);
  Register output = ToRegister(lir->output());

  if (lir->mir()->bottomHalf()) {
    masm.move32(ToRegister(input.low()), output);
  } else {
    masm.move32(ToRegister(input.high()), output);
  }
}

void CodeGenerator::visitSignExtendInt64(LSignExtendInt64* lir) {
  Register64 input = ToRegister64(lir->getInt64Operand(0));
  Register64 output = ToOutRegister64(lir);
  switch (lir->mode()) {
    case MSignExtendInt64::Byte:
      masm.move8SignExtend(input.low, output.low);
      break;
    case MSignExtendInt64::Half:
      masm.move16SignExtend(input.low, output.low);
      break;
    case MSignExtendInt64::Word:
      masm.move32(input.low, output.low);
      break;
  }
  masm.ma_sra(output.high, output.low, Imm32(31));
}

void CodeGenerator::visitClzI64(LClzI64* lir) {
  Register64 input = ToRegister64(lir->getInt64Operand(0));
  Register64 output = ToOutRegister64(lir);
  masm.clz64(input, output.low);
  masm.move32(Imm32(0), output.high);
}

void CodeGenerator::visitCtzI64(LCtzI64* lir) {
  Register64 input = ToRegister64(lir->getInt64Operand(0));
  Register64 output = ToOutRegister64(lir);
  masm.ctz64(input, output.low);
  masm.move32(Imm32(0), output.high);
}

void CodeGenerator::visitNotI64(LNotI64* lir) {
  Register64 input = ToRegister64(lir->getInt64Operand(0));
  Register output = ToRegister(lir->output());

  masm.as_or(output, input.low, input.high);
  masm.cmp32Set(Assembler::Equal, output, Imm32(0), output);
}

void CodeGenerator::visitWasmTruncateToInt64(LWasmTruncateToInt64* lir) {
  FloatRegister input = ToFloatRegister(lir->input());
  FloatRegister arg = input;
  Register64 output = ToOutRegister64(lir);
  MWasmTruncateToInt64* mir = lir->mir();
  MIRType fromType = mir->input()->type();

  auto* ool = new (alloc())
      OutOfLineWasmTruncateCheck(mir, input, Register64::Invalid());
  addOutOfLineCode(ool, mir);

  if (fromType == MIRType::Float32) {
    arg = ScratchDoubleReg;
    masm.convertFloat32ToDouble(input, arg);
  }

  if (!lir->mir()->isSaturating()) {
    masm.Push(input);

    masm.setupWasmABICall();
    masm.passABIArg(arg, MoveOp::DOUBLE);

    if (lir->mir()->isUnsigned()) {
      masm.callWithABI(mir->bytecodeOffset(),
                       wasm::SymbolicAddress::TruncateDoubleToUint64);
    } else {
      masm.callWithABI(mir->bytecodeOffset(),
                       wasm::SymbolicAddress::TruncateDoubleToInt64);
    }

    masm.Pop(input);

    masm.ma_xor(ScratchRegister, output.high, Imm32(0x80000000));
    masm.ma_or(ScratchRegister, output.low);
    masm.ma_b(ScratchRegister, Imm32(0), ool->entry(), Assembler::Equal);

    masm.bind(ool->rejoin());
  } else {
    masm.setupWasmABICall();
    masm.passABIArg(arg, MoveOp::DOUBLE);
    if (lir->mir()->isUnsigned()) {
      masm.callWithABI(mir->bytecodeOffset(),
                       wasm::SymbolicAddress::SaturatingTruncateDoubleToUint64);
    } else {
      masm.callWithABI(mir->bytecodeOffset(),
                       wasm::SymbolicAddress::SaturatingTruncateDoubleToInt64);
    }
  }

  MOZ_ASSERT(ReturnReg64 == output);
}

void CodeGenerator::visitInt64ToFloatingPoint(LInt64ToFloatingPoint* lir) {
  Register64 input = ToRegister64(lir->getInt64Operand(0));
  mozilla::DebugOnly<FloatRegister> output = ToFloatRegister(lir->output());

  MInt64ToFloatingPoint* mir = lir->mir();
  MIRType toType = mir->type();

  masm.setupWasmABICall();
  masm.passABIArg(input.high);
  masm.passABIArg(input.low);

  if (lir->mir()->isUnsigned()) {
    if (toType == MIRType::Double) {
      masm.callWithABI(mir->bytecodeOffset(),
                       wasm::SymbolicAddress::Uint64ToDouble, MoveOp::DOUBLE);
    } else {
      masm.callWithABI(mir->bytecodeOffset(),
                       wasm::SymbolicAddress::Uint64ToFloat32, MoveOp::FLOAT32);
    }
  } else {
    if (toType == MIRType::Double) {
      masm.callWithABI(mir->bytecodeOffset(),
                       wasm::SymbolicAddress::Int64ToDouble, MoveOp::DOUBLE);
    } else {
      masm.callWithABI(mir->bytecodeOffset(),
                       wasm::SymbolicAddress::Int64ToFloat32, MoveOp::FLOAT32);
    }
  }

  MOZ_ASSERT_IF(toType == MIRType::Double, *(&output) == ReturnDoubleReg);
  MOZ_ASSERT_IF(toType == MIRType::Float32, *(&output) == ReturnFloat32Reg);
}

void CodeGenerator::visitTestI64AndBranch(LTestI64AndBranch* lir) {
  Register64 input = ToRegister64(lir->getInt64Operand(0));

  branchToBlock(input.high, Imm32(0), lir->ifTrue(), Assembler::NonZero);
  emitBranch(input.low, Imm32(0), Assembler::NonZero, lir->ifTrue(),
             lir->ifFalse());
}

void CodeGenerator::visitWasmAtomicLoadI64(LWasmAtomicLoadI64* lir) {
  Register ptr = ToRegister(lir->ptr());
  Register64 output = ToOutRegister64(lir);
  uint32_t offset = lir->mir()->access().offset();

  BaseIndex addr(HeapReg, ptr, TimesOne, offset);

  masm.wasmAtomicLoad64(lir->mir()->access(), addr, Register64::Invalid(),
                        output);
}

void CodeGenerator::visitWasmAtomicStoreI64(LWasmAtomicStoreI64* lir) {
  Register ptr = ToRegister(lir->ptr());
  Register64 value = ToRegister64(lir->value());
  Register tmp = ToRegister(lir->tmp());
  uint32_t offset = lir->mir()->access().offset();

  BaseIndex addr(HeapReg, ptr, TimesOne, offset);

  masm.wasmAtomicStore64(lir->mir()->access(), addr, tmp, value);
}