//===- ModuleDepCollector.cpp - Callbacks to collect deps -------*- C++ -*-===//

//

//                     The LLVM Compiler Infrastructure

//

// This file is distributed under the University of Illinois Open Source

// License. See LICENSE.TXT for details.

//

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

#include "clang/Tooling/DependencyScanning/ModuleDepCollector.h"

#include "clang/Frontend/CompilerInstance.h"

#include "clang/Lex/Preprocessor.h"

#include "clang/Tooling/DependencyScanning/DependencyScanningWorker.h"

using namespace clang;

using namespace tooling;

using namespace dependencies;

std::vector<std::string> ModuleDeps::getFullCommandLine(

    std::function<StringRef(ClangModuleDep)> LookupPCMPath,

    std::function<const ModuleDeps &(ClangModuleDep)> LookupModuleDeps) const {

  std::vector<std::string> Ret = NonPathCommandLine;

  // TODO: Build full command line. That also means capturing the original

  //       command line into NonPathCommandLine.

  dependencies::detail::appendCommonModuleArguments(

      ClangModuleDeps, LookupPCMPath, LookupModuleDeps, Ret);

  return Ret;

}

void dependencies::detail::appendCommonModuleArguments(

    llvm::ArrayRef<ClangModuleDep> Modules,

    std::function<StringRef(ClangModuleDep)> LookupPCMPath,

    std::function<const ModuleDeps &(ClangModuleDep)> LookupModuleDeps,

    std::vector<std::string> &Result) {

  llvm::StringSet<> AlreadyAdded;

  std::function<void(llvm::ArrayRef<ClangModuleDep>)> AddArgs =

      [&](llvm::ArrayRef<ClangModuleDep> Modules) {

        for (const ClangModuleDep &CMD : Modules) {

          if (!AlreadyAdded.insert(CMD.ModuleName + CMD.ContextHash).second)

            continue;

          const ModuleDeps &M = LookupModuleDeps(CMD);

          // Depth first traversal.

          AddArgs(M.ClangModuleDeps);

          Result.push_back(("-fmodule-file=" + LookupPCMPath(CMD)).str());

          if (!M.ClangModuleMapFile.empty()) {

            Result.push_back("-fmodule-map-file=" + M.ClangModuleMapFile);

          }

        }

      };

  Result.push_back("-fno-implicit-modules");

  Result.push_back("-fno-implicit-module-maps");

  AddArgs(Modules);

}

void ModuleDepCollectorPP::FileChanged(SourceLocation Loc,

                                       FileChangeReason Reason,

                                       SrcMgr::CharacteristicKind FileType,

                                       FileID PrevFID) {

  if (Reason != PPCallbacks::EnterFile)

    return;

  // This has to be delayed as the context hash can change at the start of

  // `CompilerInstance::ExecuteAction`.

  if (MDC.ContextHash.empty()) {

    MDC.ContextHash = Instance.getInvocation().getModuleHash();

    MDC.Consumer.handleContextHash(MDC.ContextHash);

  }

  SourceManager &SM = Instance.getSourceManager();

  // Dependency generation really does want to go all the way to the

  // file entry for a source location to find out what is depended on.

  // We do not want #line markers to affect dependency generation!

  if (Optional<StringRef> Filename =

          SM.getNonBuiltinFilenameForID(SM.getFileID(SM.getExpansionLoc(Loc))))

    MDC.MainDeps.push_back(

        std::string(llvm::sys::path::remove_leading_dotslash(*Filename)));

}

void ModuleDepCollectorPP::InclusionDirective(

    SourceLocation HashLoc, const Token &IncludeTok, StringRef FileName,

    bool IsAngled, CharSourceRange FilenameRange, const FileEntry *File,

    StringRef SearchPath, StringRef RelativePath, const Module *Imported,

    SrcMgr::CharacteristicKind FileType) {

  if (!File && 
!Imported0
) {

    // This is a non-modular include that HeaderSearch failed to find. Add it

    // here as `FileChanged` will never see it.

    MDC.MainDeps.push_back(std::string(FileName));

  }

  handleImport(Imported);

}

void ModuleDepCollectorPP::moduleImport(SourceLocation ImportLoc,

                                        ModuleIdPath Path,

                                        const Module *Imported) {

  handleImport(Imported);

}

void ModuleDepCollectorPP::handleImport(const Module *Imported) {

  if (!Imported)

    return;

  MDC.Deps[MDC.ContextHash + Imported->getTopLevelModule()->getFullModuleName()]

      .ImportedByMainFile = true;

  DirectDeps.insert(Imported->getTopLevelModule());

}

void ModuleDepCollectorPP::EndOfMainFile() {

  FileID MainFileID = Instance.getSourceManager().getMainFileID();

  MDC.MainFile = std::string(

      Instance.getSourceManager().getFileEntryForID(MainFileID)->getName());

  for (const Module *M : DirectDeps) {

    handleTopLevelModule(M);

  }

  for (auto &&I : MDC.Deps)

    MDC.Consumer.handleModuleDependency(I.second);

  for (auto &&I : MDC.MainDeps)

    MDC.Consumer.handleFileDependency(*MDC.Opts, I);

}

void ModuleDepCollectorPP::handleTopLevelModule(const Module *M) {

  assert(M == M->getTopLevelModule() && "Expected top level module!");

  auto ModI = MDC.Deps.insert(

      std::make_pair(MDC.ContextHash + M->getFullModuleName(), ModuleDeps{}));

  if (!ModI.first->second.ModuleName.empty())

    return;

  ModuleDeps &MD = ModI.first->second;

  const FileEntry *ModuleMap = Instance.getPreprocessor()

                                   .getHeaderSearchInfo()

                                   .getModuleMap()

                                   .getContainingModuleMapFile(M);

  MD.ClangModuleMapFile = std::string(ModuleMap ? ModuleMap->getName() : 
""0
);

  MD.ModuleName = M->getFullModuleName();

  MD.ImplicitModulePCMPath = std::string(M->getASTFile()->getName());

  MD.ContextHash = MDC.ContextHash;

  serialization::ModuleFile *MF =

      MDC.Instance.getASTReader()->getModuleManager().lookup(M->getASTFile());

  MDC.Instance.getASTReader()->visitInputFiles(

      *MF, true, true, [&](const serialization::InputFile &IF, bool isSystem) {

        MD.FileDeps.insert(IF.getFile()->getName());

      });

  llvm::DenseSet<const Module *> AddedModules;

  addAllSubmoduleDeps(M, MD, AddedModules);

}

void ModuleDepCollectorPP::addAllSubmoduleDeps(

    const Module *M, ModuleDeps &MD,

    llvm::DenseSet<const Module *> &AddedModules) {

  addModuleDep(M, MD, AddedModules);

  for (const Module *SubM : M->submodules())

    addAllSubmoduleDeps(SubM, MD, AddedModules);

}

void ModuleDepCollectorPP::addModuleDep(

    const Module *M, ModuleDeps &MD,

    llvm::DenseSet<const Module *> &AddedModules) {

  for (const Module *Import : M->Imports) {

    if (Import->getTopLevelModule() != M->getTopLevelModule()) {

      if (AddedModules.insert(Import->getTopLevelModule()).second)

        MD.ClangModuleDeps.push_back(

            {std::string(Import->getTopLevelModuleName()),

             Instance.getInvocation().getModuleHash()});

      handleTopLevelModule(Import->getTopLevelModule());

    }

  }

}

ModuleDepCollector::ModuleDepCollector(

    std::unique_ptr<DependencyOutputOptions> Opts, CompilerInstance &I,

    DependencyConsumer &C)

    : Instance(I), Consumer(C), Opts(std::move(Opts)) {}

void ModuleDepCollector::attachToPreprocessor(Preprocessor &PP) {

  PP.addPPCallbacks(std::make_unique<ModuleDepCollectorPP>(Instance, *this));

}

void ModuleDepCollector::attachToASTReader(ASTReader &R) {}