// SPDX-License-Identifier: Apache-2.0

// SPDX-FileCopyrightText: Copyright The WasmEdge Authors

//===-- component_canon.cpp - Canonical built-in validation ---------------===//

//

// Validation of canon lift / lower / resource.* definitions.

//

//===----------------------------------------------------------------------===//

#include "common/errinfo.h"

#include "common/spdlog.h"

#include "validator/validator.h"

#include <vector>

namespace WasmEdge {

namespace Validator {

using namespace std::literals;

// canon ::= lift | lower | resource.* | async built-in, one switch per opcode.

Expect<void>

Validator::validate(const AST::Component::Canonical &Canon) noexcept {

  auto &S = CompCtx.top();

  const ValType I32V{TypeCode::I32};

  const ValType I64V{TypeCode::I64};

  // Defines the core function a canonical definition lowers to.

  auto PushCoreFunc = [&](std::vector<ValType> Params,

                          std::vector<ValType> Results) -> Expect<void> {

    S.addCoreFunc(CompTypes.addCoreFuncType(Params, Results));

    return {};

  };

  // A built-in takes its core type from the shared table, keyed on Addr.

  auto PushBuiltin = [&](const ValType &Addr) -> Expect<void> {

    auto [Params, Results] = AST::Component::Canonical::getBuiltinCoreFuncType(

        Canon.getOpCode(), Addr);

    return PushCoreFunc(std::move(Params), std::move(Results));

  };

  // The resource built-ins take no options and name a resource type.

  auto GetResourceEntry =

      [&](std::string_view What) -> Expect<const Component::TypeEntry *> {

    if (!Canon.getOptions().empty()) {

      spdlog::error(ErrCode::Value::CanonOptionOnBuiltin);

      spdlog::error("    resource built-ins take no canonical options."sv);

      return Unexpect(ErrCode::Value::CanonOptionOnBuiltin);

    }

    const auto *Entry = S.getType(Canon.getIndex());

    if (Entry == nullptr) {

      spdlog::error(ErrCode::Value::ComponentTypeIndexOutOfBounds);

      spdlog::error("    {} type index {} out of bounds."sv, What,

                    Canon.getIndex());

      return Unexpect(ErrCode::Value::ComponentTypeIndexOutOfBounds);

    }

    if (!Entry->isResource()) {

      spdlog::error(ErrCode::Value::ComponentNotResourceType);

      spdlog::error("    {} type index {} is not a resource."sv, What,

                    Canon.getIndex());

      return Unexpect(ErrCode::Value::ComponentNotResourceType);

    }

    return Entry;

  };

  // resource.new / resource.rep need a locally-defined resource and its rep.

  auto LocalResourceRep = [&](std::string_view What) -> Expect<ValType> {

    EXPECTED_TRY(const auto *Entry, GetResourceEntry(What));

    const auto &Res = CompTypes.getResource(*Entry->ResourceId);

    if (Res.RT == nullptr || Res.Origin != &S) {

      spdlog::error(ErrCode::Value::ComponentNotLocalResource);

      spdlog::error("    {} requires a locally-defined resource type."sv, What);

      return Unexpect(ErrCode::Value::ComponentNotLocalResource);

    }

    return Res.RT->isAddrI64() ? I64V : I32V;

  };

  // stream/future built-ins name their element type in the type immediate.

  auto CheckTypeImmediate =

      [&](bool WantStream) -> Expect<const Component::TypeEntry *> {

    const auto *Entry = S.getType(Canon.getIndex());

    const auto *Def = Entry != nullptr ? Entry->getDefValType() : nullptr;

    const bool Ok =

        Def != nullptr && (WantStream ? Def->isStreamTy() : Def->isFutureTy());

    if (!Ok) {

      spdlog::error(ErrCode::Value::InvalidTypeReference);

      spdlog::error("    Built-in type index {} does not refer to a {} "

                    "type."sv,

                    Canon.getIndex(), WantStream ? "stream" : "future");

      return Unexpect(ErrCode::Value::InvalidTypeReference);

    }

    return Entry;

  };

  // Option-bearing built-ins are lowerings: no post-return or callback.

  auto BuiltinOptions = [&](bool NeedMemory, bool NeedRealloc) -> Expect<void> {

    EXPECTED_TRY(CompCtx.checkOptions(Canon, false));

    return CompCtx.requireOptions(Canon, NeedMemory, NeedRealloc,

                                  "this canonical built-in"sv);

  };

  // Built-ins the spec restricts to synchronous use.

  auto RequireSync = [&]() -> Expect<void> {

    if (Canon.hasOption(ComponentCanonOptCode::Async)) {

      spdlog::error(ErrCode::Value::CanonAsyncOnBuiltin);

      spdlog::error("    this canonical built-in is always synchronous."sv);

      return Unexpect(ErrCode::Value::CanonAsyncOnBuiltin);

    }

    return {};

  };

  bool ParamsNeedMemory = false, ResultsNeedMemory = false;

  switch (Canon.getOpCode()) {

  case ComponentCanonOpCode::Lift: {

    const auto *Entry = S.getType(Canon.getTargetIndex());

    if (Entry == nullptr) {

      spdlog::error(ErrCode::Value::ComponentTypeIndexOutOfBounds);

      spdlog::error("    canon lift type index {} out of bounds."sv,

                    Canon.getTargetIndex());

      return Unexpect(ErrCode::Value::ComponentTypeIndexOutOfBounds);

    }

    if (Entry->getFuncType() == nullptr) {

      spdlog::error(ErrCode::Value::ComponentNotFunctionType);

      spdlog::error("    canon lift type index {} is not a function type."sv,

                    Canon.getTargetIndex());

      return Unexpect(ErrCode::Value::ComponentNotFunctionType);

    }

    const Component::FuncInfo FI{Entry->getFuncType(), Entry->Home,

                                 Entry->Remap};

    EXPECTED_TRY(CompCtx.checkOptions(Canon, true));

    const bool AsyncOpt = Canon.hasOption(ComponentCanonOptCode::Async);

    if (AsyncOpt && !FI.FT->isAsync()) {

      spdlog::error(ErrCode::Value::CanonAsyncRequiresAsyncType);

      spdlog::error("    canon lift with `async` needs `(func async ...)`."sv);

      return Unexpect(ErrCode::Value::CanonAsyncRequiresAsyncType);

    }

    if (Canon.hasOption(ComponentCanonOptCode::Callback) && !AsyncOpt) {

      spdlog::error(ErrCode::Value::CanonCallbackRequiresAsync);

      spdlog::error("    the `callback` option requires the `async` option."sv);

      return Unexpect(ErrCode::Value::CanonCallbackRequiresAsync);

    }

    if (AsyncOpt && Canon.hasOption(ComponentCanonOptCode::PostReturn)) {

      spdlog::error(ErrCode::Value::CanonPostReturnWithAsync);

      spdlog::error("    cannot specify post-return function in combination "

                    "with async."sv);

      return Unexpect(ErrCode::Value::CanonPostReturnWithAsync);

    }

    const ValType Ptr = CompCtx.getCanonPtrType(Canon);

    EXPECTED_TRY(auto Sig, CompTypes.flattenFuncType(FI, Ptr, ParamsNeedMemory,

                                                     ResultsNeedMemory));

    const bool ParamsIndirect =

        Sig.getParamTypes().size() > Component::TypeSystem::MaxFlatParams;

    const bool ResultsIndirect =

        Sig.getReturnTypes().size() > Component::TypeSystem::MaxFlatResults;

    if (ParamsIndirect) {

      Sig.getParamTypes().assign(1, Ptr);

    }

    if (AsyncOpt) {

      // Async lift returns the packed callback code, or nothing when stackful.

      Sig.getReturnTypes().clear();

      if (Canon.hasOption(ComponentCanonOptCode::Callback)) {

        Sig.getReturnTypes().push_back(I32V);

      }

    } else if (ResultsIndirect) {

      Sig.getReturnTypes().assign(1, Ptr);

    }

    // Required options: lifting params lowers them into the callee's memory.

    EXPECTED_TRY(CompCtx.requireOptions(

        Canon,

        ParamsNeedMemory || ParamsIndirect ||

            (!AsyncOpt && (ResultsNeedMemory || ResultsIndirect)),

        ParamsNeedMemory || ParamsIndirect, "canon lift"sv));

    // The callee must have exactly the flattened core type.

    const auto *Callee = S.getCoreFunc(Canon.getIndex());

    if (Callee == nullptr) {

      spdlog::error(ErrCode::Value::ComponentFunctionIndexOutOfBounds);

      spdlog::error("    canon lift core function index {} out of bounds."sv,

                    Canon.getIndex());

      return Unexpect(ErrCode::Value::ComponentFunctionIndexOutOfBounds);

    }

    const auto &CalleeType = Callee->getCompositeType();

    if (!CalleeType.isFunc() ||

        CalleeType.getFuncType().getParamTypes() != Sig.getParamTypes()) {

      spdlog::error(ErrCode::Value::CanonLoweredParamsMismatch);

      spdlog::error("    canon lift core function does not match the "

                    "flattened parameters."sv);

      return Unexpect(ErrCode::Value::CanonLoweredParamsMismatch);

    }

    if (CalleeType.getFuncType().getReturnTypes() != Sig.getReturnTypes()) {

      spdlog::error(ErrCode::Value::CanonLoweredResultsMismatch);

      spdlog::error("    canon lift core function does not match the "

                    "flattened results."sv);

      return Unexpect(ErrCode::Value::CanonLoweredResultsMismatch);

    }

    // post-return has type (func (param flat_results)).

    for (const auto &Opt : Canon.getOptions()) {

      if (Opt.getCode() != ComponentCanonOptCode::PostReturn) {

        continue;

      }

      const auto *Post = S.getCoreFunc(Opt.getIndex());

      if (Post == nullptr) {

        spdlog::error(ErrCode::Value::ComponentFunctionIndexOutOfBounds);

        spdlog::error("    post-return core function index {} out of bounds."sv,

                      Opt.getIndex());

        return Unexpect(ErrCode::Value::ComponentFunctionIndexOutOfBounds);

      }

      const auto &PT = Post->getCompositeType();

      if (!PT.isFunc() ||

          PT.getFuncType().getParamTypes() != Sig.getReturnTypes() ||

          !PT.getFuncType().getReturnTypes().empty()) {

        spdlog::error(ErrCode::Value::CanonPostReturnSignature);

        spdlog::error(

            "    post-return must take the lifted core results and return "

            "nothing."sv);

        return Unexpect(ErrCode::Value::CanonPostReturnSignature);

      }

    }

    S.addFunc(FI);

    return {};

  }

  case ComponentCanonOpCode::Lower: {

    const auto *FI = S.getFunc(Canon.getIndex());

    if (FI == nullptr) {

      spdlog::error(ErrCode::Value::ComponentFunctionIndexOutOfBounds);

      spdlog::error("    canon lower function index {} out of bounds."sv,

                    Canon.getIndex());

      return Unexpect(ErrCode::Value::ComponentFunctionIndexOutOfBounds);

    }

    EXPECTED_TRY(CompCtx.checkOptions(Canon, false));

    const bool AsyncOpt = Canon.hasOption(ComponentCanonOptCode::Async);

    if (FI->FT == nullptr) {

      spdlog::error(ErrCode::Value::InvalidTypeReference);

      return Unexpect(ErrCode::Value::InvalidTypeReference);

    }

    if (AsyncOpt && !FI->FT->isAsync()) {

      spdlog::error(ErrCode::Value::CanonAsyncRequiresAsyncType);

      spdlog::error("    canon lower with `async` needs `(func async ...)`."sv);

      return Unexpect(ErrCode::Value::CanonAsyncRequiresAsyncType);

    }

    const ValType Ptr = CompCtx.getCanonPtrType(Canon);

    EXPECTED_TRY(auto Sig, CompTypes.flattenFuncType(*FI, Ptr, ParamsNeedMemory,

                                                     ResultsNeedMemory));

    const bool ParamsIndirect =

        Sig.getParamTypes().size() >

        (AsyncOpt ? Component::TypeSystem::MaxFlatAsyncParams

                  : Component::TypeSystem::MaxFlatParams);

    const bool ResultsIndirect =

        AsyncOpt ? !Sig.getReturnTypes().empty()

                 : Sig.getReturnTypes().size() >

                       Component::TypeSystem::MaxFlatResults;

    if (ParamsIndirect) {

      Sig.getParamTypes().assign(1, Ptr);

    }

    if (ResultsIndirect) {

      // The caller passes a pointer for the results as the last parameter.

      Sig.getParamTypes().push_back(Ptr);

      Sig.getReturnTypes().clear();

    }

    if (AsyncOpt) {

      // Async lower: the core function returns the packed subtask state.

      Sig.getReturnTypes().assign(1, I32V);

    }

    EXPECTED_TRY(CompCtx.requireOptions(Canon,

                                        ParamsNeedMemory || ResultsNeedMemory ||

                                            ParamsIndirect || ResultsIndirect,

                                        ResultsNeedMemory, "canon lower"sv));

    return PushCoreFunc(Sig.getParamTypes(), Sig.getReturnTypes());

  }

  case ComponentCanonOpCode::Resource__new: {

    EXPECTED_TRY(const auto Rep, LocalResourceRep("resource.new"sv));

    return PushCoreFunc({Rep}, {I32V});

  }

  case ComponentCanonOpCode::Resource__rep: {

    EXPECTED_TRY(const auto Rep, LocalResourceRep("resource.rep"sv));

    return PushCoreFunc({I32V}, {Rep});

  }

  case ComponentCanonOpCode::Resource__drop:

    EXPECTED_TRY(GetResourceEntry("resource.drop"sv));

    return PushCoreFunc({I32V}, {});

  // Async built-ins take their core signatures from the shared table.

  case ComponentCanonOpCode::Backpressure__inc:

  case ComponentCanonOpCode::Backpressure__dec:

    return PushBuiltin(I32V);

  case ComponentCanonOpCode::Thread__index:

    return PushBuiltin(I32V);

  case ComponentCanonOpCode::Task__return: {

    // The results lower as the core parameters; task.return never reallocates.

    EXPECTED_TRY(CompCtx.checkOptions(Canon, false));

    if (Canon.hasOption(ComponentCanonOptCode::Realloc)) {

      spdlog::error(ErrCode::Value::CanonReallocOnBuiltin);

      spdlog::error("    realloc cannot be specified for task.return."sv);

      return Unexpect(ErrCode::Value::CanonReallocOnBuiltin);

    }

    EXPECTED_TRY(RequireSync());

    const ValType Ptr = CompCtx.getCanonPtrType(Canon);

    std::vector<ValType> Params;

    for (const auto &R : Canon.getResultList()) {

      const Component::QualValType Q{R.getValType(), &S, nullptr};

      if (!CompTypes.flattenValType(Q, Params, Ptr)) {

        spdlog::error(ErrCode::Value::InvalidTypeReference);

        return Unexpect(ErrCode::Value::InvalidTypeReference);

      }

      ParamsNeedMemory = ParamsNeedMemory || CompTypes.needsMemory(Q);

    }

    if (Params.size() > Component::TypeSystem::MaxFlatParams) {

      Params.assign(1, Ptr);

      ParamsNeedMemory = true;

    }

    EXPECTED_TRY(CompCtx.requireOptions(Canon, ParamsNeedMemory, false,

                                        "task.return"sv));

    return PushCoreFunc(std::move(Params), {});

  }

  case ComponentCanonOpCode::Task__cancel:

    return PushBuiltin(I32V);

  case ComponentCanonOpCode::Context__get:

  case ComponentCanonOpCode::Context__set: {

    const bool IsGet = Canon.getOpCode() == ComponentCanonOpCode::Context__get;

    const std::string_view Name = IsGet ? "context.get"sv : "context.set"sv;

    // The slot immediate is stored as the constant value, not as an index.

    if (Canon.getConstVal() >= Component::TypeSystem::MaxContextSlots) {

      spdlog::error(ErrCode::Value::ComponentContextSlotOutOfBounds);

      spdlog::error(

          "    Context slot {} out of bounds, must be less than {}."sv,

          Canon.getConstVal(), Component::TypeSystem::MaxContextSlots);

      return Unexpect(ErrCode::Value::ComponentContextSlotOutOfBounds);

    }

    const ValType Ty = Canon.getContextType();

    if (Ty != I32V && Ty != I64V) {

      spdlog::error(ErrCode::Value::ComponentContextTypeInvalid);

      spdlog::error("    `{}` only supports `i32` or `i64`."sv, Name);

      return Unexpect(ErrCode::Value::ComponentContextTypeInvalid);

    }

    // A 64-bit slot is gated the same way a 64-bit resource rep is.

    if (Ty == I64V && !Conf.hasProposal(Proposal::Memory64)) {

      spdlog::error(ErrCode::Value::ComponentContextTypeInvalid);

      spdlog::error(ErrInfo::InfoProposal(Proposal::Memory64));

      spdlog::error("    a 64-bit `{}` needs the memory64 proposal."sv, Name);

      return Unexpect(ErrCode::Value::ComponentContextTypeInvalid);

    }

    // The whole component shares one thread-local slot type.

    auto &Shared = CompCtx.top().ContextType;

    if (Shared.has_value() && *Shared != Ty) {

      spdlog::error(ErrCode::Value::ComponentContextTypeMismatch);

      spdlog::error("    `{}` type must match previous context type."sv, Name);

      return Unexpect(ErrCode::Value::ComponentContextTypeMismatch);

    }

    Shared = Ty;

    if (IsGet) {

      return PushCoreFunc({}, {Ty});

    }

    return PushCoreFunc({Ty}, {});

  }

  case ComponentCanonOpCode::Yield:

    return PushBuiltin(I32V);

  case ComponentCanonOpCode::Subtask__cancel:

    return PushBuiltin(I32V);

  case ComponentCanonOpCode::Subtask__drop:

    return PushBuiltin(I32V);

  case ComponentCanonOpCode::Stream__new:

    EXPECTED_TRY(CheckTypeImmediate(true));

    return PushBuiltin(I32V);

  case ComponentCanonOpCode::Stream__read:

  case ComponentCanonOpCode::Stream__write: {

    EXPECTED_TRY(const auto *Entry, CheckTypeImmediate(true));

    const auto &Elem = Entry->getDefValType()->getStream().ValTy;

    // Reading a payload that allocates needs realloc; writing never does.

    const bool NeedRealloc =

        Canon.getOpCode() == ComponentCanonOpCode::Stream__read &&

        Elem.has_value() &&

        CompTypes.needsMemory({*Elem, Entry->Home, Entry->Remap});

    EXPECTED_TRY(BuiltinOptions(Elem.has_value(), NeedRealloc));

    return PushBuiltin(CompCtx.getCanonPtrType(Canon));

  }

  case ComponentCanonOpCode::Stream__cancel_read:

  case ComponentCanonOpCode::Stream__cancel_write:

    EXPECTED_TRY(CheckTypeImmediate(true));

    return PushBuiltin(I32V);

  case ComponentCanonOpCode::Stream__drop_readable:

  case ComponentCanonOpCode::Stream__drop_writable:

    EXPECTED_TRY(CheckTypeImmediate(true));

    return PushBuiltin(I32V);

  case ComponentCanonOpCode::Future__new:

    EXPECTED_TRY(CheckTypeImmediate(false));

    return PushBuiltin(I32V);

  case ComponentCanonOpCode::Future__read:

  case ComponentCanonOpCode::Future__write: {

    EXPECTED_TRY(const auto *Entry, CheckTypeImmediate(false));

    const auto &Elem = Entry->getDefValType()->getFuture().ValTy;

    // Reading a payload that allocates needs realloc; writing never does.

    const bool NeedRealloc =

        Canon.getOpCode() == ComponentCanonOpCode::Future__read &&

        Elem.has_value() &&

        CompTypes.needsMemory({*Elem, Entry->Home, Entry->Remap});

    EXPECTED_TRY(BuiltinOptions(Elem.has_value(), NeedRealloc));

    return PushBuiltin(CompCtx.getCanonPtrType(Canon));

  }

  case ComponentCanonOpCode::Future__cancel_read:

  case ComponentCanonOpCode::Future__cancel_write:

    EXPECTED_TRY(CheckTypeImmediate(false));

    return PushBuiltin(I32V);

  case ComponentCanonOpCode::Future__drop_readable:

  case ComponentCanonOpCode::Future__drop_writable:

    EXPECTED_TRY(CheckTypeImmediate(false));

    return PushBuiltin(I32V);

  case ComponentCanonOpCode::Error_context__new:

    EXPECTED_TRY(BuiltinOptions(true, false));

    EXPECTED_TRY(RequireSync());

    return PushBuiltin(CompCtx.getCanonPtrType(Canon));

  case ComponentCanonOpCode::Error_context__debug_message:

    EXPECTED_TRY(BuiltinOptions(true, true));

    EXPECTED_TRY(RequireSync());

    return PushBuiltin(CompCtx.getCanonPtrType(Canon));

  case ComponentCanonOpCode::Error_context__drop:

    return PushBuiltin(I32V);

  case ComponentCanonOpCode::Waitable_set__new:

    return PushBuiltin(I32V);

  case ComponentCanonOpCode::Waitable_set__wait:

  case ComponentCanonOpCode::Waitable_set__poll: {

    if (Canon.getIndex() >= S.CoreMemories.size()) {

      spdlog::error(ErrCode::Value::ComponentMemoryIndexOutOfBounds);

      spdlog::error("    Canonical built-in memory index {} out of bounds."sv,

                    Canon.getIndex());

      return Unexpect(ErrCode::Value::ComponentMemoryIndexOutOfBounds);

    }

    // The payload address carries the address type of the given memory.

    const auto *Mem = S.CoreMemories[Canon.getIndex()];

    const ValType Addr =

        ValType(Mem != nullptr && Mem->getLimit().is64() ? TypeCode::I64

                                                         : TypeCode::I32);

    return PushBuiltin(Addr);

  }

  case ComponentCanonOpCode::Waitable_set__drop:

    return PushBuiltin(I32V);

  case ComponentCanonOpCode::Waitable__join:

    return PushBuiltin(I32V);

  case ComponentCanonOpCode::Thread__new_indirect: {

    // The start type must be (func (param i32)) and the target a core table.

    const auto *CT = S.getCoreType(Canon.getIndex());

    const bool TypeOk =

        CT != nullptr && CT->Func != nullptr &&

        CT->Func->getCompositeType().isFunc() &&

        CT->Func->getCompositeType().getFuncType().getParamTypes() ==

            std::vector<ValType>{I32V} &&

        CT->Func->getCompositeType().getFuncType().getReturnTypes().empty();

    if (!TypeOk) {

      spdlog::error(ErrCode::Value::InvalidTypeReference);

      spdlog::error(

          "    thread.new-indirect start type must be (func (param i32))."sv);

      return Unexpect(ErrCode::Value::InvalidTypeReference);

    }

    if (Canon.getTargetIndex() >= S.CoreTables.size()) {

      spdlog::error(ErrCode::Value::DefTypeIndexOutOfBounds);

      spdlog::error("    thread.new-indirect table index {} out of bounds."sv,

                    Canon.getTargetIndex());

      return Unexpect(ErrCode::Value::DefTypeIndexOutOfBounds);

    }

    // The thread index carries the address type of the table.

    const auto *Tab = S.CoreTables[Canon.getTargetIndex()];

    return PushBuiltin(ValType(Tab != nullptr && Tab->getLimit().is64()

                                   ? TypeCode::I64

                                   : TypeCode::I32));

  }

  case ComponentCanonOpCode::Thread__resume_later:

    return PushBuiltin(I32V);

  case ComponentCanonOpCode::Thread__suspend:

    return PushBuiltin(I32V);

  case ComponentCanonOpCode::Thread__suspend_then_resume:

  case ComponentCanonOpCode::Thread__yield_then_resume:

  case ComponentCanonOpCode::Thread__suspend_then_promote:

  case ComponentCanonOpCode::Thread__yield_then_promote:

    return PushBuiltin(I32V);

  default:

    spdlog::error(ErrCode::Value::ComponentNotImplValidator);

    spdlog::error("    canonical built-in {} is not supported yet."sv,

                  static_cast<uint32_t>(Canon.getOpCode()));

    return Unexpect(ErrCode::Value::ComponentNotImplValidator);

  }

}

} // namespace Validator

} // namespace WasmEdge