WebAssemblyRegisterBankInfo.cpp

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//===-- WebAssemblyRegisterBankInfo.cpp -------------------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
/// \file
/// This file implements the targeting of the RegisterBankInfo class for
/// WebAssembly.
/// \todo This should be generated by TableGen.
//===----------------------------------------------------------------------===//
 
#include "WebAssemblyRegisterBankInfo.h"
#include "MCTargetDesc/WebAssemblyMCTargetDesc.h"
#include "WebAssemblyRegisterInfo.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/TargetRegisterInfo.h"
 
#define GET_TARGET_REGBANK_IMPL
 
#include "WebAssemblyGenRegisterBank.inc"
 
namespace llvm {
namespace WebAssembly {
enum PartialMappingIdx {
  PMI_None = -1,
  PMI_I32 = 1,
  PMI_I64,
  PMI_Min = PMI_I32,
};
 
enum ValueMappingIdx {
  InvalidIdx = 0,
  I32Idx = 1,
  I64Idx = 5,
};
 
const RegisterBankInfo::PartialMapping PartMappings[]{{0, 32, I32RegBank},
                                                      {0, 64, I64RegBank}};
 
const RegisterBankInfo::ValueMapping ValueMappings[] = {
    // invalid
    {nullptr, 0},
    // up to 4 operands as I32
    {&PartMappings[PMI_I32 - PMI_Min], 1},
    {&PartMappings[PMI_I32 - PMI_Min], 1},
    {&PartMappings[PMI_I32 - PMI_Min], 1},
    {&PartMappings[PMI_I32 - PMI_Min], 1},
    // up to 4 operands as I64
    {&PartMappings[PMI_I64 - PMI_Min], 1},
    {&PartMappings[PMI_I64 - PMI_Min], 1},
    {&PartMappings[PMI_I64 - PMI_Min], 1},
    {&PartMappings[PMI_I64 - PMI_Min], 1},
};
} // namespace WebAssembly
} // namespace llvm
 
using namespace llvm;
 
WebAssemblyRegisterBankInfo::WebAssemblyRegisterBankInfo(
    const TargetRegisterInfo &TRI) {}
 
const RegisterBankInfo::InstructionMapping &
WebAssemblyRegisterBankInfo::getInstrMapping(const MachineInstr &MI) const {
  unsigned Opc = MI.getOpcode();
  const MachineFunction &MF = *MI.getParent()->getParent();
  const MachineRegisterInfo &MRI = MF.getRegInfo();
 
  if ((Opc != TargetOpcode::COPY && !isPreISelGenericOpcode(Opc)) ||
      Opc == TargetOpcode::G_PHI) {
    const RegisterBankInfo::InstructionMapping &Mapping =
        getInstrMappingImpl(MI);
    if (Mapping.isValid())
      return Mapping;
  }
 
  const unsigned NumOperands = MI.getNumOperands();
  const ValueMapping *OperandsMapping = nullptr;
  unsigned MappingID = DefaultMappingID;
 
  const LLT Op0Ty = MRI.getType(MI.getOperand(0).getReg());
  unsigned Op0Size = Op0Ty.getSizeInBits();
 
  auto &Op0IntValueMapping =
      WebAssembly::ValueMappings[Op0Size == 64 ? WebAssembly::I64Idx
                                               : WebAssembly::I32Idx];
 
  using namespace TargetOpcode;
  switch (Opc) {
  case G_ADD:
  case G_AND:
  case G_ASHR:
  case G_SHL:
    OperandsMapping = &Op0IntValueMapping;
    break;
  case G_CONSTANT:
    OperandsMapping = getOperandsMapping({&Op0IntValueMapping, nullptr});
    break;
  }
 
  if (!OperandsMapping)
    return getInvalidInstructionMapping();
 
  return getInstructionMapping(MappingID, /*Cost=*/1, OperandsMapping,
                               NumOperands);
}