//===-- WebAssemblySelectionDAGInfo.cpp - WebAssembly SelectionDAG Info ---===//
//
// 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 WebAssemblySelectionDAGInfo class.
///
//===----------------------------------------------------------------------===//

#include "WebAssemblyTargetMachine.h"
using namespace llvm;

#define DEBUG_TYPE "wasm-selectiondag-info"

WebAssemblySelectionDAGInfo::~WebAssemblySelectionDAGInfo() = default; // anchor

bool WebAssemblySelectionDAGInfo::isTargetMemoryOpcode(unsigned Opcode) const {
  switch (static_cast<WebAssemblyISD::NodeType>(Opcode)) {
  default:
    return false;
  case WebAssemblyISD::GLOBAL_GET:
  case WebAssemblyISD::GLOBAL_SET:
  case WebAssemblyISD::TABLE_GET:
  case WebAssemblyISD::TABLE_SET:
    return true;
  }
}

SDValue WebAssemblySelectionDAGInfo::EmitTargetCodeForMemcpy(
    SelectionDAG &DAG, const SDLoc &DL, SDValue Chain, SDValue Dst, SDValue Src,
    SDValue Size, Align Alignment, bool IsVolatile, bool AlwaysInline,
    MachinePointerInfo DstPtrInfo, MachinePointerInfo SrcPtrInfo) const {
  auto &ST = DAG.getMachineFunction().getSubtarget<WebAssemblySubtarget>();
  if (!ST.hasBulkMemoryOpt())
    return SDValue();

  SDValue MemIdx = DAG.getConstant(0, DL, MVT::i32);
  auto LenMVT = ST.hasAddr64() ? MVT::i64 : MVT::i32;

  // Use `MEMCPY` here instead of `MEMORY_COPY` because `memory.copy` traps
  // if the pointers are invalid even if the length is zero. `MEMCPY` gets
  // extra code to handle this in the way that LLVM IR expects.
  return DAG.getNode(
      WebAssemblyISD::MEMCPY, DL, MVT::Other,
      {Chain, MemIdx, MemIdx, Dst, Src, DAG.getZExtOrTrunc(Size, DL, LenMVT)});
}

SDValue WebAssemblySelectionDAGInfo::EmitTargetCodeForMemmove(
    SelectionDAG &DAG, const SDLoc &DL, SDValue Chain, SDValue Op1, SDValue Op2,
    SDValue Op3, Align Alignment, bool IsVolatile,
    MachinePointerInfo DstPtrInfo, MachinePointerInfo SrcPtrInfo) const {
  return EmitTargetCodeForMemcpy(DAG, DL, Chain, Op1, Op2, Op3,
                                 Alignment, IsVolatile, false,
                                 DstPtrInfo, SrcPtrInfo);
}

SDValue WebAssemblySelectionDAGInfo::EmitTargetCodeForMemset(
    SelectionDAG &DAG, const SDLoc &DL, SDValue Chain, SDValue Dst, SDValue Val,
    SDValue Size, Align Alignment, bool IsVolatile, bool AlwaysInline,
    MachinePointerInfo DstPtrInfo) const {
  auto &ST = DAG.getMachineFunction().getSubtarget<WebAssemblySubtarget>();
  if (!ST.hasBulkMemoryOpt())
    return SDValue();

  SDValue MemIdx = DAG.getConstant(0, DL, MVT::i32);
  auto LenMVT = ST.hasAddr64() ? MVT::i64 : MVT::i32;

  // Use `MEMSET` here instead of `MEMORY_FILL` because `memory.fill` traps
  // if the pointers are invalid even if the length is zero. `MEMSET` gets
  // extra code to handle this in the way that LLVM IR expects.
  //
  // Only low byte matters for val argument, so anyext the i8
  return DAG.getNode(WebAssemblyISD::MEMSET, DL, MVT::Other, Chain, MemIdx, Dst,
                     DAG.getAnyExtOrTrunc(Val, DL, MVT::i32),
                     DAG.getZExtOrTrunc(Size, DL, LenMVT));
}