//===-- 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 "WebAssemblySelectionDAGInfo.h"
#include "WebAssemblyTargetMachine.h"

#define GET_SDNODE_DESC
#include "WebAssemblyGenSDNodeInfo.inc"

using namespace llvm;

#define DEBUG_TYPE "wasm-selectiondag-info"

WebAssemblySelectionDAGInfo::WebAssemblySelectionDAGInfo()
    : SelectionDAGGenTargetInfo(WebAssemblyGenSDNodeInfo) {}

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

const char *
WebAssemblySelectionDAGInfo::getTargetNodeName(unsigned Opcode) const {
  switch (static_cast<WebAssemblyISD::NodeType>(Opcode)) {
  case WebAssemblyISD::CALL:
    return "WebAssemblyISD::CALL";
  case WebAssemblyISD::RET_CALL:
    return "WebAssemblyISD::RET_CALL";
  }

  return SelectionDAGGenTargetInfo::getTargetNodeName(Opcode);
}

SDValue WebAssemblySelectionDAGInfo::EmitTargetCodeForMemcpy(
    SelectionDAG &DAG, const SDLoc &DL, SDValue Chain, SDValue Dst, SDValue Src,
    SDValue Size, Align DstAlign, Align SrcAlign, 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 DstAlign, Align SrcAlign, bool IsVolatile,
    MachinePointerInfo DstPtrInfo, MachinePointerInfo SrcPtrInfo) const {
  return EmitTargetCodeForMemcpy(DAG, DL, Chain, Op1, Op2, Op3, DstAlign,
                                 SrcAlign, 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));
}