// SPDX-License-Identifier: Apache-2.0

// SPDX-FileCopyrightText: Copyright The WasmEdge Authors

#include "executor/executor.h"

#include <cstdint>

namespace WasmEdge {

namespace Executor {

// Instantiate table instance. See "include/executor/executor.h".

Expect<void> Executor::instantiate(Runtime::StackManager &StackMgr,

                                   Runtime::Instance::ModuleInstance &ModInst,

                                   const AST::TableSection &TabSec) {

  // A frame with the temporary module is pushed onto the stack by the caller.

  // Prepare the table-size and element-buffer pointers vectors for compiled

  // functions.

  ModInst.TableSizePtrs.resize(ModInst.getTableNum() +

                               TabSec.getContent().size());

  ModInst.TableRefPtrs.resize(ModInst.getTableNum() +

                              TabSec.getContent().size());

  // Set the table pointers of imported tables.

  for (uint32_t I = 0; I < ModInst.getTableNum(); ++I) {

    auto *TabInst = ModInst.unsafeGetTable(I);

    ModInst.TableSizePtrs[I] = TabInst->getSizePtr();

    ModInst.TableRefPtrs[I] = &TabInst->getDataPtr();

  }

  // Iterate through the table segments to instantiate and initialize table

  // instances.

  for (const auto &TabSeg : TabSec.getContent()) {

    if (TabSeg.getExpr().getInstrs().size() > 0) {

      // Run the initialization expression.

      EXPECTED_TRY(runExpression(StackMgr, TabSeg.getExpr().getInstrs())

                       .map_error([](auto E) {

                         spdlog::error(

                             ErrInfo::InfoAST(ASTNodeAttr::Expression));

                         return E;

                       }));

      // Pop result from the stack.

      RefVariant InitTabValue = StackMgr.pop().get<RefVariant>();

      // Create and add the table instance to the module instance.

      ModInst.addTable(TabSeg.getTableType(), InitTabValue);

    } else {

      // No init expression case. Use the null reference to initialize.

      // Normalize the type to the bottom abstract heap type so that null

      // references always carry abstract types, as ref.cast/ref.test assume.

      auto BotType = toBottomType(StackMgr, TabSeg.getTableType().getRefType());

      RefVariant InitTabValue(ValType(TypeCode::RefNull, BotType));

      ModInst.addTable(TabSeg.getTableType(), InitTabValue);

    }

    // Set the table pointers of the instantiated table.

    const auto Index = ModInst.getTableNum() - 1;

    auto *TabInst = ModInst.unsafeGetTable(Index);

    ModInst.TableSizePtrs[Index] = TabInst->getSizePtr();

    ModInst.TableRefPtrs[Index] = &TabInst->getDataPtr();

  }

  return {};

}

} // namespace Executor

} // namespace WasmEdge