// SPDX-License-Identifier: Apache-2.0

// SPDX-FileCopyrightText: Copyright The WasmEdge Authors

#include "compiler/context.h"

#include <algorithm>

#include <array>

#include <cstdint>

#include <initializer_list>

#include <string_view>

#include <utility>

#include <vector>

using namespace std::literals;

namespace WasmEdge::LLVM {

Compiler::CompileContext::CompileContext(LLVM::Context C, LLVM::Module &M,

                                         bool IsGenericBinary) noexcept

    : LLContext(C), LLModule(M),

      Cold(LLVM::Attribute::createEnum(C, LLVM::Core::Cold, 0)),

      NoAlias(LLVM::Attribute::createEnum(C, LLVM::Core::NoAlias, 0)),

      NoInline(LLVM::Attribute::createEnum(C, LLVM::Core::NoInline, 0)),

      NoReturn(LLVM::Attribute::createEnum(C, LLVM::Core::NoReturn, 0)),

      ReadOnly(LLVM::Attribute::createEnum(C, LLVM::Core::ReadOnly, 0)),

      StrictFP(LLVM::Attribute::createEnum(C, LLVM::Core::StrictFP, 0)),

      UWTable(LLVM::Attribute::createEnum(C, LLVM::Core::UWTable,

                                          LLVM::Core::UWTableDefault)),

      NoStackArgProbe(

          LLVM::Attribute::createString(C, "no-stack-arg-probe"sv, {})),

      VoidTy(LLContext.getVoidTy()), Int8Ty(LLContext.getInt8Ty()),

      Int16Ty(LLContext.getInt16Ty()), Int32Ty(LLContext.getInt32Ty()),

      Int64Ty(LLContext.getInt64Ty()), Int128Ty(LLContext.getInt128Ty()),

      FloatTy(LLContext.getFloatTy()), DoubleTy(LLContext.getDoubleTy()),

      Int8x16Ty(LLVM::Type::getVectorType(Int8Ty, 16)),

      Int16x8Ty(LLVM::Type::getVectorType(Int16Ty, 8)),

      Int32x4Ty(LLVM::Type::getVectorType(Int32Ty, 4)),

      Floatx4Ty(LLVM::Type::getVectorType(FloatTy, 4)),

      Int64x2Ty(LLVM::Type::getVectorType(Int64Ty, 2)),

      Doublex2Ty(LLVM::Type::getVectorType(DoubleTy, 2)),

      Int128x1Ty(LLVM::Type::getVectorType(Int128Ty, 1)),

      Int8PtrTy(Int8Ty.getPointerTo()), Int32PtrTy(Int32Ty.getPointerTo()),

      Int64PtrTy(Int64Ty.getPointerTo()), Int128PtrTy(Int128Ty.getPointerTo()),

      Int8PtrPtrTy(Int8PtrTy.getPointerTo()),

      ExecCtxTy(LLVM::Type::getStructType(

          "ExecCtx",

          std::initializer_list<LLVM::Type>{

              // MemoryPtrs

              Int8PtrTy.getPointerTo(),

              // MemorySizes

              Int64PtrTy.getPointerTo(),

              // TableRefs

              Int64x2Ty.getPointerTo().getPointerTo(),

              // TableSizes

              Int64PtrTy.getPointerTo(),

              // Globals

              Int128PtrTy.getPointerTo(),

              // InstrCount

              Int64PtrTy,

              // CostTable

              LLVM::Type::getArrayType(Int64Ty, UINT16_MAX + 1).getPointerTo(),

              // Gas

              Int64PtrTy,

              // GasLimit

              Int64Ty,

              // StopToken

              Int32PtrTy,

              // ModuleInst

              Int8PtrTy,

          })),

      ExecCtxPtrTy(ExecCtxTy.getPointerTo()),

      IntrinsicsTableTy(LLVM::Type::getArrayType(

          Int8Ty.getPointerTo(),

          static_cast<uint32_t>(Executable::Intrinsics::kIntrinsicMax))),

      IntrinsicsTablePtrTy(IntrinsicsTableTy.getPointerTo()),

      IntrinsicsTable(LLModule.get().addGlobal(IntrinsicsTablePtrTy, true,

                                               LLVMExternalLinkage,

                                               LLVM::Value(), "intrinsics")) {

  Trap.Ty = LLVM::Type::getFunctionType(VoidTy, {Int32Ty});

  Trap.Fn = LLModule.get().addFunction(Trap.Ty, LLVMPrivateLinkage, "trap");

  Trap.Fn.setDSOLocal(true);

  Trap.Fn.addFnAttr(NoStackArgProbe);

  Trap.Fn.addFnAttr(StrictFP);

  Trap.Fn.addFnAttr(UWTable);

  Trap.Fn.addFnAttr(NoReturn);

  Trap.Fn.addFnAttr(Cold);

  Trap.Fn.addFnAttr(NoInline);

  if (!IsGenericBinary) {

    SubtargetFeatures = LLVM::getHostCPUFeatures();

    auto Features = SubtargetFeatures.string_view();

    while (!Features.empty()) {

      std::string_view Feature;

      if (auto Pos = Features.find(','); Pos != std::string_view::npos) {

        Feature = Features.substr(0, Pos);

        Features = Features.substr(Pos + 1);

      } else {

        Feature = std::exchange(Features, std::string_view());

      }

      if (Feature[0] != '+') {

        continue;

      }

      Feature = Feature.substr(1);

#if defined(__x86_64__)

      if (!SupportXOP && Feature == "xop"sv) {

        SupportXOP = true;

      }

      if (!SupportSSE4_1 && Feature == "sse4.1"sv) {

        SupportSSE4_1 = true;

      }

      if (!SupportSSSE3 && Feature == "ssse3"sv) {

        SupportSSSE3 = true;

      }

      if (!SupportSSE2 && Feature == "sse2"sv) {

        SupportSSE2 = true;

      }

#elif defined(__aarch64__)

      if (!SupportNEON && Feature == "neon"sv) {

        SupportNEON = true;

      }

#endif

    }

  }

  compileTrap();

}

bool isVoidReturn(Span<const ValType> ValTypes) noexcept {

  return ValTypes.empty();

}

LLVM::Type toLLVMType(LLVM::Context LLContext,

                      const ValType &ValType) noexcept {

  switch (ValType.getCode()) {

  case TypeCode::I32:

    return LLContext.getInt32Ty();

  case TypeCode::I64:

    return LLContext.getInt64Ty();

  case TypeCode::Ref:

  case TypeCode::RefNull:

  case TypeCode::V128:

    return LLVM::Type::getVectorType(LLContext.getInt64Ty(), 2);

  case TypeCode::F32:

    return LLContext.getFloatTy();

  case TypeCode::F64:

    return LLContext.getDoubleTy();

  default:

    assumingUnreachable();

  }

}

LLVM::Type toLLVMType(LLVM::Context LLContext,

                      const AddressType AddrType) noexcept {

  switch (AddrType) {

  case AddressType::I32:

    return LLContext.getInt32Ty();

  case AddressType::I64:

    return LLContext.getInt64Ty();

  default:

    assumingUnreachable();

  }

}

std::vector<LLVM::Type>

toLLVMTypeVector(LLVM::Context LLContext,

                 Span<const ValType> ValTypes) noexcept {

  std::vector<LLVM::Type> Result;

  Result.reserve(ValTypes.size());

  for (const auto &Type : ValTypes) {

    Result.push_back(toLLVMType(LLContext, Type));

  }

  return Result;

}

std::vector<LLVM::Type> toLLVMArgsType(LLVM::Context LLContext,

                                       LLVM::Type ExecCtxPtrTy,

                                       Span<const ValType> ValTypes) noexcept {

  auto Result = toLLVMTypeVector(LLContext, ValTypes);

  Result.insert(Result.begin(), ExecCtxPtrTy);

  return Result;

}

LLVM::Type toLLVMRetsType(LLVM::Context LLContext,

                          Span<const ValType> ValTypes) noexcept {

  if (isVoidReturn(ValTypes)) {

    return LLContext.getVoidTy();

  }

  if (ValTypes.size() == 1) {

    return toLLVMType(LLContext, ValTypes.front());

  }

  std::vector<LLVM::Type> Result;

  Result.reserve(ValTypes.size());

  for (const auto &Type : ValTypes) {

    Result.push_back(toLLVMType(LLContext, Type));

  }

  return LLVM::Type::getStructType(Result);

}

LLVM::Type toLLVMType(LLVM::Context LLContext, LLVM::Type ExecCtxPtrTy,

                      const AST::FunctionType &FuncType) noexcept {

  auto ArgsTy =

      toLLVMArgsType(LLContext, ExecCtxPtrTy, FuncType.getParamTypes());

  auto RetTy = toLLVMRetsType(LLContext, FuncType.getReturnTypes());

  return LLVM::Type::getFunctionType(RetTy, ArgsTy);

}

LLVM::Value toLLVMConstantZero(

    LLVM::Context LLContext, const ValType &ValType,

    Span<const AST::CompositeType *const> CompositeTypes) noexcept {

  switch (ValType.getCode()) {

  case TypeCode::I32:

    return LLVM::Value::getConstNull(LLContext.getInt32Ty());

  case TypeCode::I64:

    return LLVM::Value::getConstNull(LLContext.getInt64Ty());

  case TypeCode::Ref:

  case TypeCode::RefNull: {

    std::array<uint8_t, 16> Data{};

    if (ValType.isAbsHeapType()) {

      // Abstract heap types are already fine for null refs.

      const auto Raw = ValType.getRawData();

      std::copy(Raw.begin(), Raw.end(), Data.begin());

    } else {

      // For non-abstract heap types (concrete type indices), convert to the

      // abstract heap type so that ref.cast/ref.test won't dereference a null

      // pointer when checking the type.

      assuming(ValType.getTypeIndex() < CompositeTypes.size());

      const auto *CompType = CompositeTypes[ValType.getTypeIndex()];

      assuming(CompType != nullptr);

      WasmEdge::ValType VType =

          CompType->isFunc() ? TypeCode::NullFuncRef : TypeCode::NullRef;

      std::copy_n(VType.getRawData().cbegin(), 8, Data.begin());

    }

    return LLVM::Value::getConstVector8(LLContext, Data);

  }

  case TypeCode::V128:

    return LLVM::Value::getConstNull(

        LLVM::Type::getVectorType(LLContext.getInt64Ty(), 2));

  case TypeCode::F32:

    return LLVM::Value::getConstNull(LLContext.getFloatTy());

  case TypeCode::F64:

    return LLVM::Value::getConstNull(LLContext.getDoubleTy());

  default:

    assumingUnreachable();

  }

}

std::vector<LLVM::Value> unpackStruct(LLVM::Builder &Builder,

                                      LLVM::Value Struct) noexcept {

  const auto N = Struct.getType().getStructNumElements();

  std::vector<LLVM::Value> Ret;

  Ret.reserve(N);

  for (unsigned I = 0; I < N; ++I) {

    Ret.push_back(Builder.createExtractValue(Struct, I));

  }

  return Ret;

}

} // namespace WasmEdge::LLVM