//===---------------- EPCDynamicLibrarySearchGenerator.cpp ----------------===//
//
// 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
//
//===----------------------------------------------------------------------===//

#include "llvm/ExecutionEngine/Orc/EPCDynamicLibrarySearchGenerator.h"

namespace llvm {
namespace orc {

Expected<std::unique_ptr<EPCDynamicLibrarySearchGenerator>>
EPCDynamicLibrarySearchGenerator::Load(
    ExecutionSession &ES, const char *LibraryPath, SymbolPredicate Allow,
    AddAbsoluteSymbolsFn AddAbsoluteSymbols) {
  auto Handle = ES.getExecutorProcessControl().loadDylib(LibraryPath);
  if (!Handle)
    return Handle.takeError();

  return std::make_unique<EPCDynamicLibrarySearchGenerator>(
      ES, *Handle, std::move(Allow), std::move(AddAbsoluteSymbols));
}

Error EPCDynamicLibrarySearchGenerator::tryToGenerate(
    LookupState &LS, LookupKind K, JITDylib &JD,
    JITDylibLookupFlags JDLookupFlags, const SymbolLookupSet &Symbols) {

  if (Symbols.empty())
    return Error::success();

  SymbolLookupSet LookupSymbols;

  for (auto &KV : Symbols) {
    // Skip symbols that don't match the filter.
    if (Allow && !Allow(KV.first))
      continue;
    LookupSymbols.add(KV.first, SymbolLookupFlags::WeaklyReferencedSymbol);
  }

  SymbolMap NewSymbols;

  ExecutorProcessControl::LookupRequest Request(H, LookupSymbols);
  auto Result = EPC.lookupSymbols(Request);
  if (!Result)
    return Result.takeError();

  assert(Result->size() == 1 && "Results for more than one library returned");
  assert(Result->front().size() == LookupSymbols.size() &&
         "Result has incorrect number of elements");

  auto ResultI = Result->front().begin();
  for (auto &KV : LookupSymbols) {
    if (ResultI->getAddress())
      NewSymbols[KV.first] = *ResultI;
    ++ResultI;
  }

  // If there were no resolved symbols bail out.
  if (NewSymbols.empty())
    return Error::success();

  // Define resolved symbols.
  if (AddAbsoluteSymbols)
    return AddAbsoluteSymbols(JD, std::move(NewSymbols));
  return JD.define(absoluteSymbols(std::move(NewSymbols)));
}

} // end namespace orc
} // end namespace llvm