tools/libclang/Indexing.cpp

//===- CIndexHigh.cpp - Higher level API functions ------------------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

#include "IndexingContext.h"
#include "CXCursor.h"
#include "CXSourceLocation.h"
#include "CXTranslationUnit.h"
#include "CXString.h"
#include "CIndexDiagnostic.h"
#include "CIndexer.h"

#include "clang/Frontend/ASTUnit.h"
#include "clang/Frontend/CompilerInvocation.h"
#include "clang/Frontend/CompilerInstance.h"
#include "clang/Frontend/FrontendAction.h"
#include "clang/Frontend/Utils.h"
#include "clang/Sema/SemaConsumer.h"
#include "clang/AST/ASTConsumer.h"
#include "clang/AST/DeclVisitor.h"
#include "clang/Lex/Preprocessor.h"
#include "clang/Lex/PPCallbacks.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/CrashRecoveryContext.h"

using namespace clang;
using namespace cxstring;
using namespace cxtu;
using namespace cxindex;

static void indexDiagnostics(CXTranslationUnit TU, IndexingContext &IdxCtx);

namespace {

//===----------------------------------------------------------------------===//
// IndexPPCallbacks
//===----------------------------------------------------------------------===//

class IndexPPCallbacks : public PPCallbacks {
  Preprocessor &PP;
  IndexingContext &IndexCtx;
  bool IsMainFileEntered;

public:
  IndexPPCallbacks(Preprocessor &PP, IndexingContext &indexCtx)
    : PP(PP), IndexCtx(indexCtx), IsMainFileEntered(false) { }

  virtual void FileChanged(SourceLocation Loc, FileChangeReason Reason,
                          SrcMgr::CharacteristicKind FileType, FileID PrevFID) {
    if (IsMainFileEntered)
      return;

    SourceManager &SM = PP.getSourceManager();
    SourceLocation MainFileLoc = SM.getLocForStartOfFile(SM.getMainFileID());

    if (Loc == MainFileLoc && Reason == PPCallbacks::EnterFile) {
      IsMainFileEntered = true;
      IndexCtx.enteredMainFile(SM.getFileEntryForID(SM.getMainFileID()));
    }
  }

  virtual void InclusionDirective(SourceLocation HashLoc,
                                  const Token &IncludeTok,
                                  StringRef FileName,
                                  bool IsAngled,
                                  CharSourceRange FilenameRange,
                                  const FileEntry *File,
                                  StringRef SearchPath,
                                  StringRef RelativePath,
                                  const Module *Imported) {
    if (Imported) {
      IndexCtx.importedModule(HashLoc, FileName, /*isIncludeDirective=*/true,
                              Imported);
      return;
    }

    bool isImport = (IncludeTok.is(tok::identifier) &&
            IncludeTok.getIdentifierInfo()->getPPKeywordID() == tok::pp_import);
    IndexCtx.ppIncludedFile(HashLoc, FileName, File, isImport, IsAngled);
  }

  /// MacroDefined - This hook is called whenever a macro definition is seen.
  virtual void MacroDefined(const Token &Id, const MacroInfo *MI) {
  }

  /// MacroUndefined - This hook is called whenever a macro #undef is seen.
  /// MI is released immediately following this callback.
  virtual void MacroUndefined(const Token &MacroNameTok, const MacroInfo *MI) {
  }

  /// MacroExpands - This is called by when a macro invocation is found.
  virtual void MacroExpands(const Token &MacroNameTok, const MacroInfo* MI,
                            SourceRange Range) {
  }
  
  /// SourceRangeSkipped - This hook is called when a source range is skipped.
  /// \param Range The SourceRange that was skipped. The range begins at the
  /// #if/#else directive and ends after the #endif/#else directive.
  virtual void SourceRangeSkipped(SourceRange Range) {
  }
};

//===----------------------------------------------------------------------===//
// IndexingConsumer
//===----------------------------------------------------------------------===//

class IndexingConsumer : public ASTConsumer {
  IndexingContext &IndexCtx;

public:
  explicit IndexingConsumer(IndexingContext &indexCtx)
    : IndexCtx(indexCtx) { }

  // ASTConsumer Implementation

  virtual void Initialize(ASTContext &Context) {
    IndexCtx.setASTContext(Context);
    IndexCtx.startedTranslationUnit();
  }

  virtual void HandleTranslationUnit(ASTContext &Ctx) {
  }

  virtual bool HandleTopLevelDecl(DeclGroupRef DG) {
    IndexCtx.indexDeclGroupRef(DG);
    return !IndexCtx.shouldAbort();
  }

  /// \brief Handle the specified top-level declaration that occurred inside
  /// and ObjC container.
  virtual void HandleTopLevelDeclInObjCContainer(DeclGroupRef D) {
    // They will be handled after the interface is seen first.
    IndexCtx.addTUDeclInObjCContainer(D);
  }

  /// \brief This is called by the AST reader when deserializing things.
  /// The default implementation forwards to HandleTopLevelDecl but we don't
  /// care about them when indexing, so have an empty definition.
  virtual void HandleInterestingDecl(DeclGroupRef D) {}

  virtual void HandleTagDeclDefinition(TagDecl *D) {
    if (!IndexCtx.shouldIndexImplicitTemplateInsts())
      return;

    if (IndexCtx.isTemplateImplicitInstantiation(D))
      IndexCtx.indexDecl(D);
  }

  virtual void HandleCXXImplicitFunctionInstantiation(FunctionDecl *D) {
    if (!IndexCtx.shouldIndexImplicitTemplateInsts())
      return;

    IndexCtx.indexDecl(D);
  }
};

//===----------------------------------------------------------------------===//
// CaptureDiagnosticConsumer
//===----------------------------------------------------------------------===//

class CaptureDiagnosticConsumer : public DiagnosticConsumer {
  SmallVector<StoredDiagnostic, 4> Errors;
public:

  virtual void HandleDiagnostic(DiagnosticsEngine::Level level,
                                const Diagnostic &Info) {
    if (level >= DiagnosticsEngine::Error)
      Errors.push_back(StoredDiagnostic(level, Info));
  }

  DiagnosticConsumer *clone(DiagnosticsEngine &Diags) const {
    return new IgnoringDiagConsumer();
  }
};

//===----------------------------------------------------------------------===//
// IndexingFrontendAction
//===----------------------------------------------------------------------===//

class IndexingFrontendAction : public ASTFrontendAction {
  IndexingContext IndexCtx;
  CXTranslationUnit CXTU;

public:
  IndexingFrontendAction(CXClientData clientData,
                         IndexerCallbacks &indexCallbacks,
                         unsigned indexOptions,
                         CXTranslationUnit cxTU)
    : IndexCtx(clientData, indexCallbacks, indexOptions, cxTU),
      CXTU(cxTU), EnablePPDetailedRecordForModules(false) { }

  bool EnablePPDetailedRecordForModules;

  virtual ASTConsumer *CreateASTConsumer(CompilerInstance &CI,
                                         StringRef InFile) {
    // We usually disable the preprocessing record for indexing even if the
    // original preprocessing options had it enabled. Now that the indexing
    // Preprocessor has been created (without a preprocessing record), re-enable
    // the option in case modules are enabled, so that the detailed record
    // option can be propagated when the module file is generated.
    if (CI.getLangOpts().Modules && EnablePPDetailedRecordForModules)
      CI.getPreprocessorOpts().DetailedRecord = true;

    IndexCtx.setASTContext(CI.getASTContext());
    Preprocessor &PP = CI.getPreprocessor();
    PP.addPPCallbacks(new IndexPPCallbacks(PP, IndexCtx));
    IndexCtx.setPreprocessor(PP);
    return new IndexingConsumer(IndexCtx);
  }

  virtual void EndSourceFileAction() {
    indexDiagnostics(CXTU, IndexCtx);
  }

  virtual TranslationUnitKind getTranslationUnitKind() {
    if (IndexCtx.shouldIndexImplicitTemplateInsts())
      return TU_Complete;
    else
      return TU_Prefix;
  }
  virtual bool hasCodeCompletionSupport() const { return false; }
};

//===----------------------------------------------------------------------===//
// clang_indexSourceFileUnit Implementation
//===----------------------------------------------------------------------===//

struct IndexSourceFileInfo {
  CXIndexAction idxAction;
  CXClientData client_data;
  IndexerCallbacks *index_callbacks;
  unsigned index_callbacks_size;
  unsigned index_options;
  const char *source_filename;
  const char *const *command_line_args;
  int num_command_line_args;
  struct CXUnsavedFile *unsaved_files;
  unsigned num_unsaved_files;
  CXTranslationUnit *out_TU;
  unsigned TU_options;
  int result;
};

struct MemBufferOwner {
  SmallVector<const llvm::MemoryBuffer *, 8> Buffers;
  
  ~MemBufferOwner() {
    for (SmallVectorImpl<const llvm::MemoryBuffer *>::iterator
           I = Buffers.begin(), E = Buffers.end(); I != E; ++I)
      delete *I;
  }
};

} // anonymous namespace

static void clang_indexSourceFile_Impl(void *UserData) {
  IndexSourceFileInfo *ITUI =
    static_cast<IndexSourceFileInfo*>(UserData);
  CXIndex CIdx = (CXIndex)ITUI->idxAction;
  CXClientData client_data = ITUI->client_data;
  IndexerCallbacks *client_index_callbacks = ITUI->index_callbacks;
  unsigned index_callbacks_size = ITUI->index_callbacks_size;
  unsigned index_options = ITUI->index_options;
  const char *source_filename = ITUI->source_filename;
  const char * const *command_line_args = ITUI->command_line_args;
  int num_command_line_args = ITUI->num_command_line_args;
  struct CXUnsavedFile *unsaved_files = ITUI->unsaved_files;
  unsigned num_unsaved_files = ITUI->num_unsaved_files;
  CXTranslationUnit *out_TU  = ITUI->out_TU;
  unsigned TU_options = ITUI->TU_options;
  ITUI->result = 1; // init as error.
  
  if (out_TU)
    *out_TU = 0;
  bool requestedToGetTU = (out_TU != 0); 

  if (!CIdx)
    return;
  if (!client_index_callbacks || index_callbacks_size == 0)
    return;

  IndexerCallbacks CB;
  memset(&CB, 0, sizeof(CB));
  unsigned ClientCBSize = index_callbacks_size < sizeof(CB)
                                  ? index_callbacks_size : sizeof(CB);
  memcpy(&CB, client_index_callbacks, ClientCBSize);

  CIndexer *CXXIdx = static_cast<CIndexer *>(CIdx);

  if (CXXIdx->isOptEnabled(CXGlobalOpt_ThreadBackgroundPriorityForIndexing))
    setThreadBackgroundPriority();

  CaptureDiagnosticConsumer *CaptureDiag = new CaptureDiagnosticConsumer();

  // Configure the diagnostics.
  DiagnosticOptions DiagOpts;
  IntrusiveRefCntPtr<DiagnosticsEngine>
    Diags(CompilerInstance::createDiagnostics(DiagOpts, num_command_line_args, 
                                                command_line_args,
                                                CaptureDiag,
                                                /*ShouldOwnClient=*/true,
                                                /*ShouldCloneClient=*/false));

  // Recover resources if we crash before exiting this function.
  llvm::CrashRecoveryContextCleanupRegistrar<DiagnosticsEngine,
    llvm::CrashRecoveryContextReleaseRefCleanup<DiagnosticsEngine> >
    DiagCleanup(Diags.getPtr());
  
  OwningPtr<std::vector<const char *> >
    Args(new std::vector<const char*>());

  // Recover resources if we crash before exiting this method.
  llvm::CrashRecoveryContextCleanupRegistrar<std::vector<const char*> >
    ArgsCleanup(Args.get());
  
  Args->insert(Args->end(), command_line_args,
               command_line_args + num_command_line_args);

  // The 'source_filename' argument is optional.  If the caller does not
  // specify it then it is assumed that the source file is specified
  // in the actual argument list.
  // Put the source file after command_line_args otherwise if '-x' flag is
  // present it will be unused.
  if (source_filename)
    Args->push_back(source_filename);
  
  IntrusiveRefCntPtr<CompilerInvocation>
    CInvok(createInvocationFromCommandLine(*Args, Diags));

  if (!CInvok)
    return;

  // Recover resources if we crash before exiting this function.
  llvm::CrashRecoveryContextCleanupRegistrar<CompilerInvocation,
    llvm::CrashRecoveryContextReleaseRefCleanup<CompilerInvocation> >
    CInvokCleanup(CInvok.getPtr());

  if (CInvok->getFrontendOpts().Inputs.empty())
    return;

  OwningPtr<MemBufferOwner> BufOwner(new MemBufferOwner());

  // Recover resources if we crash before exiting this method.
  llvm::CrashRecoveryContextCleanupRegistrar<MemBufferOwner>
    BufOwnerCleanup(BufOwner.get());

  for (unsigned I = 0; I != num_unsaved_files; ++I) {
    StringRef Data(unsaved_files[I].Contents, unsaved_files[I].Length);
    const llvm::MemoryBuffer *Buffer
      = llvm::MemoryBuffer::getMemBufferCopy(Data, unsaved_files[I].Filename);
    CInvok->getPreprocessorOpts().addRemappedFile(unsaved_files[I].Filename, Buffer);
    BufOwner->Buffers.push_back(Buffer);
  }

  // Since libclang is primarily used by batch tools dealing with
  // (often very broken) source code, where spell-checking can have a
  // significant negative impact on performance (particularly when 
  // precompiled headers are involved), we disable it.
  CInvok->getLangOpts()->SpellChecking = false;

  if (index_options & CXIndexOpt_SuppressWarnings)
    CInvok->getDiagnosticOpts().IgnoreWarnings = true;

  ASTUnit *Unit = ASTUnit::create(CInvok.getPtr(), Diags,
                                  /*CaptureDiagnostics=*/true,
                                  /*UserFilesAreVolatile=*/true);
  OwningPtr<CXTUOwner> CXTU(new CXTUOwner(MakeCXTranslationUnit(CXXIdx, Unit)));

  // Recover resources if we crash before exiting this method.
  llvm::CrashRecoveryContextCleanupRegistrar<CXTUOwner>
    CXTUCleanup(CXTU.get());

  OwningPtr<IndexingFrontendAction> IndexAction;
  IndexAction.reset(new IndexingFrontendAction(client_data, CB,
                                               index_options, CXTU->getTU()));

  // Recover resources if we crash before exiting this method.
  llvm::CrashRecoveryContextCleanupRegistrar<IndexingFrontendAction>
    IndexActionCleanup(IndexAction.get());

  bool Persistent = requestedToGetTU;
  bool OnlyLocalDecls = false;
  bool PrecompilePreamble = false;
  bool CacheCodeCompletionResults = false;
  PreprocessorOptions &PPOpts = CInvok->getPreprocessorOpts(); 
  PPOpts.AllowPCHWithCompilerErrors = true;

  if (requestedToGetTU) {
    OnlyLocalDecls = CXXIdx->getOnlyLocalDecls();
    PrecompilePreamble = TU_options & CXTranslationUnit_PrecompiledPreamble;
    // FIXME: Add a flag for modules.
    CacheCodeCompletionResults
      = TU_options & CXTranslationUnit_CacheCompletionResults;
    if (TU_options & CXTranslationUnit_DetailedPreprocessingRecord) {
      PPOpts.DetailedRecord = true;
    }
  }

  IndexAction->EnablePPDetailedRecordForModules
    = PPOpts.DetailedRecord ||
      (TU_options & CXTranslationUnit_DetailedPreprocessingRecord);

  if (!requestedToGetTU)
    PPOpts.DetailedRecord = false;

  DiagnosticErrorTrap DiagTrap(*Diags);
  bool Success = ASTUnit::LoadFromCompilerInvocationAction(CInvok.getPtr(), Diags,
                                                       IndexAction.get(),
                                                       Unit,
                                                       Persistent,
                                                CXXIdx->getClangResourcesPath(),
                                                       OnlyLocalDecls,
                                                    /*CaptureDiagnostics=*/true,
                                                       PrecompilePreamble,
                                                    CacheCodeCompletionResults,
                                 /*IncludeBriefCommentsInCodeCompletion=*/false,
                                                 /*UserFilesAreVolatile=*/true);
  if (DiagTrap.hasErrorOccurred() && CXXIdx->getDisplayDiagnostics())
    printDiagsToStderr(Unit);

  if (!Success)
    return;

  if (out_TU)
    *out_TU = CXTU->takeTU();

  ITUI->result = 0; // success.
}

//===----------------------------------------------------------------------===//
// clang_indexTranslationUnit Implementation
//===----------------------------------------------------------------------===//

namespace {

struct IndexTranslationUnitInfo {
  CXIndexAction idxAction;
  CXClientData client_data;
  IndexerCallbacks *index_callbacks;
  unsigned index_callbacks_size;
  unsigned index_options;
  CXTranslationUnit TU;
  int result;
};

} // anonymous namespace

static void indexPreprocessingRecord(ASTUnit &Unit, IndexingContext &IdxCtx) {
  Preprocessor &PP = Unit.getPreprocessor();
  if (!PP.getPreprocessingRecord())
    return;

  // FIXME: Only deserialize inclusion directives.

  PreprocessingRecord::iterator I, E;
  llvm::tie(I, E) = Unit.getLocalPreprocessingEntities();

  for (; I != E; ++I) {
    PreprocessedEntity *PPE = *I;

    if (InclusionDirective *ID = dyn_cast<InclusionDirective>(PPE)) {
      if (!ID->importedModule())
        IdxCtx.ppIncludedFile(ID->getSourceRange().getBegin(),ID->getFileName(),
                     ID->getFile(), ID->getKind() == InclusionDirective::Import,
                     !ID->wasInQuotes());
    }
  }
}

static bool topLevelDeclVisitor(void *context, const Decl *D) {
  IndexingContext &IdxCtx = *static_cast<IndexingContext*>(context);
  IdxCtx.indexTopLevelDecl(D);
  if (IdxCtx.shouldAbort())
    return false;
  return true;
}

static void indexTranslationUnit(ASTUnit &Unit, IndexingContext &IdxCtx) {
  Unit.visitLocalTopLevelDecls(&IdxCtx, topLevelDeclVisitor);
}

static void indexDiagnostics(CXTranslationUnit TU, IndexingContext &IdxCtx) {
  if (!IdxCtx.hasDiagnosticCallback())
    return;

  CXDiagnosticSetImpl *DiagSet = cxdiag::lazyCreateDiags(TU);
  IdxCtx.handleDiagnosticSet(DiagSet);
}

static void clang_indexTranslationUnit_Impl(void *UserData) {
  IndexTranslationUnitInfo *ITUI =
    static_cast<IndexTranslationUnitInfo*>(UserData);
  CXTranslationUnit TU = ITUI->TU;
  CXClientData client_data = ITUI->client_data;
  IndexerCallbacks *client_index_callbacks = ITUI->index_callbacks;
  unsigned index_callbacks_size = ITUI->index_callbacks_size;
  unsigned index_options = ITUI->index_options;
  ITUI->result = 1; // init as error.

  if (!TU)
    return;
  if (!client_index_callbacks || index_callbacks_size == 0)
    return;

  CIndexer *CXXIdx = (CIndexer*)TU->CIdx;
  if (CXXIdx->isOptEnabled(CXGlobalOpt_ThreadBackgroundPriorityForIndexing))
    setThreadBackgroundPriority();

  IndexerCallbacks CB;
  memset(&CB, 0, sizeof(CB));
  unsigned ClientCBSize = index_callbacks_size < sizeof(CB)
                                  ? index_callbacks_size : sizeof(CB);
  memcpy(&CB, client_index_callbacks, ClientCBSize);

  OwningPtr<IndexingContext> IndexCtx;
  IndexCtx.reset(new IndexingContext(client_data, CB, index_options, TU));

  // Recover resources if we crash before exiting this method.
  llvm::CrashRecoveryContextCleanupRegistrar<IndexingContext>
    IndexCtxCleanup(IndexCtx.get());

  OwningPtr<IndexingConsumer> IndexConsumer;
  IndexConsumer.reset(new IndexingConsumer(*IndexCtx));

  // Recover resources if we crash before exiting this method.
  llvm::CrashRecoveryContextCleanupRegistrar<IndexingConsumer>
    IndexConsumerCleanup(IndexConsumer.get());

  ASTUnit *Unit = static_cast<ASTUnit *>(TU->TUData);
  if (!Unit)
    return;

  ASTUnit::ConcurrencyCheck Check(*Unit);

  FileManager &FileMgr = Unit->getFileManager();

  if (Unit->getOriginalSourceFileName().empty())
    IndexCtx->enteredMainFile(0);
  else
    IndexCtx->enteredMainFile(FileMgr.getFile(Unit->getOriginalSourceFileName()));

  IndexConsumer->Initialize(Unit->getASTContext());

  indexPreprocessingRecord(*Unit, *IndexCtx);
  indexTranslationUnit(*Unit, *IndexCtx);
  indexDiagnostics(TU, *IndexCtx);

  ITUI->result = 0;
}

//===----------------------------------------------------------------------===//
// libclang public APIs.
//===----------------------------------------------------------------------===//

extern "C" {

int clang_index_isEntityObjCContainerKind(CXIdxEntityKind K) {
  return CXIdxEntity_ObjCClass <= K && K <= CXIdxEntity_ObjCCategory;
}

const CXIdxObjCContainerDeclInfo *
clang_index_getObjCContainerDeclInfo(const CXIdxDeclInfo *DInfo) {
  if (!DInfo)
    return 0;

  const DeclInfo *DI = static_cast<const DeclInfo *>(DInfo);
  if (const ObjCContainerDeclInfo *
        ContInfo = dyn_cast<ObjCContainerDeclInfo>(DI))
    return &ContInfo->ObjCContDeclInfo;

  return 0;
}

const CXIdxObjCInterfaceDeclInfo *
clang_index_getObjCInterfaceDeclInfo(const CXIdxDeclInfo *DInfo) {
  if (!DInfo)
    return 0;

  const DeclInfo *DI = static_cast<const DeclInfo *>(DInfo);
  if (const ObjCInterfaceDeclInfo *
        InterInfo = dyn_cast<ObjCInterfaceDeclInfo>(DI))
    return &InterInfo->ObjCInterDeclInfo;

  return 0;
}

const CXIdxObjCCategoryDeclInfo *
clang_index_getObjCCategoryDeclInfo(const CXIdxDeclInfo *DInfo){
  if (!DInfo)
    return 0;

  const DeclInfo *DI = static_cast<const DeclInfo *>(DInfo);
  if (const ObjCCategoryDeclInfo *
        CatInfo = dyn_cast<ObjCCategoryDeclInfo>(DI))
    return &CatInfo->ObjCCatDeclInfo;

  return 0;
}

const CXIdxObjCProtocolRefListInfo *
clang_index_getObjCProtocolRefListInfo(const CXIdxDeclInfo *DInfo) {
  if (!DInfo)
    return 0;

  const DeclInfo *DI = static_cast<const DeclInfo *>(DInfo);
  
  if (const ObjCInterfaceDeclInfo *
        InterInfo = dyn_cast<ObjCInterfaceDeclInfo>(DI))
    return InterInfo->ObjCInterDeclInfo.protocols;
  
  if (const ObjCProtocolDeclInfo *
        ProtInfo = dyn_cast<ObjCProtocolDeclInfo>(DI))
    return &ProtInfo->ObjCProtoRefListInfo;

  if (const ObjCCategoryDeclInfo *CatInfo = dyn_cast<ObjCCategoryDeclInfo>(DI))
    return CatInfo->ObjCCatDeclInfo.protocols;

  return 0;
}

const CXIdxObjCPropertyDeclInfo *
clang_index_getObjCPropertyDeclInfo(const CXIdxDeclInfo *DInfo) {
  if (!DInfo)
    return 0;

  const DeclInfo *DI = static_cast<const DeclInfo *>(DInfo);
  if (const ObjCPropertyDeclInfo *PropInfo = dyn_cast<ObjCPropertyDeclInfo>(DI))
    return &PropInfo->ObjCPropDeclInfo;

  return 0;
}

const CXIdxIBOutletCollectionAttrInfo *
clang_index_getIBOutletCollectionAttrInfo(const CXIdxAttrInfo *AInfo) {
  if (!AInfo)
    return 0;

  const AttrInfo *DI = static_cast<const AttrInfo *>(AInfo);
  if (const IBOutletCollectionInfo *
        IBInfo = dyn_cast<IBOutletCollectionInfo>(DI))
    return &IBInfo->IBCollInfo;

  return 0;
}

const CXIdxCXXClassDeclInfo *
clang_index_getCXXClassDeclInfo(const CXIdxDeclInfo *DInfo) {
  if (!DInfo)
    return 0;

  const DeclInfo *DI = static_cast<const DeclInfo *>(DInfo);
  if (const CXXClassDeclInfo *ClassInfo = dyn_cast<CXXClassDeclInfo>(DI))
    return &ClassInfo->CXXClassInfo;

  return 0;
}

CXIdxClientContainer
clang_index_getClientContainer(const CXIdxContainerInfo *info) {
  if (!info)
    return 0;
  const ContainerInfo *Container = static_cast<const ContainerInfo *>(info);
  return Container->IndexCtx->getClientContainerForDC(Container->DC);
}

void clang_index_setClientContainer(const CXIdxContainerInfo *info,
                                    CXIdxClientContainer client) {
  if (!info)
    return;
  const ContainerInfo *Container = static_cast<const ContainerInfo *>(info);
  Container->IndexCtx->addContainerInMap(Container->DC, client);
}

CXIdxClientEntity clang_index_getClientEntity(const CXIdxEntityInfo *info) {
  if (!info)
    return 0;
  const EntityInfo *Entity = static_cast<const EntityInfo *>(info);
  return Entity->IndexCtx->getClientEntity(Entity->Dcl);
}

void clang_index_setClientEntity(const CXIdxEntityInfo *info,
                                 CXIdxClientEntity client) {
  if (!info)
    return;
  const EntityInfo *Entity = static_cast<const EntityInfo *>(info);
  Entity->IndexCtx->setClientEntity(Entity->Dcl, client);
}

CXIndexAction clang_IndexAction_create(CXIndex CIdx) {
  // For now, CXIndexAction is featureless. 
  return CIdx;
}

void clang_IndexAction_dispose(CXIndexAction idxAction) {
  // For now, CXIndexAction is featureless. 
}

int clang_indexSourceFile(CXIndexAction idxAction,
                          CXClientData client_data,
                          IndexerCallbacks *index_callbacks,
                          unsigned index_callbacks_size,
                          unsigned index_options,
                          const char *source_filename,
                          const char * const *command_line_args,
                          int num_command_line_args,
                          struct CXUnsavedFile *unsaved_files,
                          unsigned num_unsaved_files,
                          CXTranslationUnit *out_TU,
                          unsigned TU_options) {

  IndexSourceFileInfo ITUI = { idxAction, client_data, index_callbacks,
                               index_callbacks_size, index_options,
                               source_filename, command_line_args,
                               num_command_line_args, unsaved_files,
                               num_unsaved_files, out_TU, TU_options, 0 };

  if (getenv("LIBCLANG_NOTHREADS")) {
    clang_indexSourceFile_Impl(&ITUI);
    return ITUI.result;
  }

  llvm::CrashRecoveryContext CRC;

  if (!RunSafely(CRC, clang_indexSourceFile_Impl, &ITUI)) {
    fprintf(stderr, "libclang: crash detected during indexing source file: {\n");
    fprintf(stderr, "  'source_filename' : '%s'\n", source_filename);
    fprintf(stderr, "  'command_line_args' : [");
    for (int i = 0; i != num_command_line_args; ++i) {
      if (i)
        fprintf(stderr, ", ");
      fprintf(stderr, "'%s'", command_line_args[i]);
    }
    fprintf(stderr, "],\n");
    fprintf(stderr, "  'unsaved_files' : [");
    for (unsigned i = 0; i != num_unsaved_files; ++i) {
      if (i)
        fprintf(stderr, ", ");
      fprintf(stderr, "('%s', '...', %ld)", unsaved_files[i].Filename,
              unsaved_files[i].Length);
    }
    fprintf(stderr, "],\n");
    fprintf(stderr, "  'options' : %d,\n", TU_options);
    fprintf(stderr, "}\n");
    
    return 1;
  } else if (getenv("LIBCLANG_RESOURCE_USAGE")) {
    if (out_TU)
      PrintLibclangResourceUsage(*out_TU);
  }
  
  return ITUI.result;
}

int clang_indexTranslationUnit(CXIndexAction idxAction,
                               CXClientData client_data,
                               IndexerCallbacks *index_callbacks,
                               unsigned index_callbacks_size,
                               unsigned index_options,
                               CXTranslationUnit TU) {

  IndexTranslationUnitInfo ITUI = { idxAction, client_data, index_callbacks,
                                    index_callbacks_size, index_options, TU,
                                    0 };

  if (getenv("LIBCLANG_NOTHREADS")) {
    clang_indexTranslationUnit_Impl(&ITUI);
    return ITUI.result;
  }

  llvm::CrashRecoveryContext CRC;

  if (!RunSafely(CRC, clang_indexTranslationUnit_Impl, &ITUI)) {
    fprintf(stderr, "libclang: crash detected during indexing TU\n");
    
    return 1;
  }

  return ITUI.result;
}

void clang_indexLoc_getFileLocation(CXIdxLoc location,
                                    CXIdxClientFile *indexFile,
                                    CXFile *file,
                                    unsigned *line,
                                    unsigned *column,
                                    unsigned *offset) {
  if (indexFile) *indexFile = 0;
  if (file)   *file = 0;
  if (line)   *line = 0;
  if (column) *column = 0;
  if (offset) *offset = 0;

  SourceLocation Loc = SourceLocation::getFromRawEncoding(location.int_data);
  if (!location.ptr_data[0] || Loc.isInvalid())
    return;

  IndexingContext &IndexCtx =
      *static_cast<IndexingContext*>(location.ptr_data[0]);
  IndexCtx.translateLoc(Loc, indexFile, file, line, column, offset);
}

CXSourceLocation clang_indexLoc_getCXSourceLocation(CXIdxLoc location) {
  SourceLocation Loc = SourceLocation::getFromRawEncoding(location.int_data);
  if (!location.ptr_data[0] || Loc.isInvalid())
    return clang_getNullLocation();

  IndexingContext &IndexCtx =
      *static_cast<IndexingContext*>(location.ptr_data[0]);
  return cxloc::translateSourceLocation(IndexCtx.getASTContext(), Loc);
}

} // end: extern "C"