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//===--- CrossTranslationUnit.cpp - -----------------------------*- C++ -*-===//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
// This file implements the CrossTranslationUnit interface.
#include "clang/CrossTU/CrossTranslationUnit.h"
#include "clang/AST/ASTImporter.h"
#include "clang/AST/Decl.h"
#include "clang/Basic/TargetInfo.h"
#include "clang/CrossTU/CrossTUDiagnostic.h"
#include "clang/Frontend/ASTUnit.h"
#include "clang/Frontend/CompilerInstance.h"
#include "clang/Frontend/TextDiagnosticPrinter.h"
#include "clang/Index/USRGeneration.h"
#include "llvm/ADT/Triple.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/ManagedStatic.h"
#include "llvm/Support/Path.h"
#include "llvm/Support/raw_ostream.h"
#include <fstream>
#include <sstream>
namespace clang {
namespace cross_tu {
namespace {
#define DEBUG_TYPE "CrossTranslationUnit"
STATISTIC(NumGetCTUCalled, "The # of getCTUDefinition function called");
"The # of getCTUDefinition called but the function is not in any other TU");
"The # of getCTUDefinition successfully returned the "
"requested function's body");
STATISTIC(NumUnsupportedNodeFound, "The # of imports when the ASTImporter "
"encountered an unsupported AST Node");
STATISTIC(NumNameConflicts, "The # of imports when the ASTImporter "
"encountered an ODR error");
STATISTIC(NumTripleMismatch, "The # of triple mismatches");
STATISTIC(NumLangMismatch, "The # of language mismatches");
STATISTIC(NumLangDialectMismatch, "The # of language dialect mismatches");
"The # of ASTs not loaded because of threshold");
// Same as Triple's equality operator, but we check a field only if that is
// known in both instances.
bool hasEqualKnownFields(const llvm::Triple &Lhs, const llvm::Triple &Rhs) {
using llvm::Triple;
if (Lhs.getArch() != Triple::UnknownArch &&
Rhs.getArch() != Triple::UnknownArch && Lhs.getArch() != Rhs.getArch())
return false;
if (Lhs.getSubArch() != Triple::NoSubArch &&
Rhs.getSubArch() != Triple::NoSubArch &&
Lhs.getSubArch() != Rhs.getSubArch())
return false;
if (Lhs.getVendor() != Triple::UnknownVendor &&
Rhs.getVendor() != Triple::UnknownVendor &&
Lhs.getVendor() != Rhs.getVendor())
return false;
if (!Lhs.isOSUnknown() && !Rhs.isOSUnknown() &&
Lhs.getOS() != Rhs.getOS())
return false;
if (Lhs.getEnvironment() != Triple::UnknownEnvironment &&
Rhs.getEnvironment() != Triple::UnknownEnvironment &&
Lhs.getEnvironment() != Rhs.getEnvironment())
return false;
if (Lhs.getObjectFormat() != Triple::UnknownObjectFormat &&
Rhs.getObjectFormat() != Triple::UnknownObjectFormat &&
Lhs.getObjectFormat() != Rhs.getObjectFormat())
return false;
return true;
// FIXME: This class is will be removed after the transition to llvm::Error.
class IndexErrorCategory : public std::error_category {
const char *name() const noexcept override { return "clang.index"; }
std::string message(int Condition) const override {
switch (static_cast<index_error_code>(Condition)) {
case index_error_code::unspecified:
return "An unknown error has occurred.";
case index_error_code::missing_index_file:
return "The index file is missing.";
case index_error_code::invalid_index_format:
return "Invalid index file format.";
case index_error_code::multiple_definitions:
return "Multiple definitions in the index file.";
case index_error_code::missing_definition:
return "Missing definition from the index file.";
case index_error_code::failed_import:
return "Failed to import the definition.";
case index_error_code::failed_to_get_external_ast:
return "Failed to load external AST source.";
case index_error_code::failed_to_generate_usr:
return "Failed to generate USR.";
case index_error_code::triple_mismatch:
return "Triple mismatch";
case index_error_code::lang_mismatch:
return "Language mismatch";
case index_error_code::lang_dialect_mismatch:
return "Language dialect mismatch";
case index_error_code::load_threshold_reached:
return "Load threshold reached";
llvm_unreachable("Unrecognized index_error_code.");
static llvm::ManagedStatic<IndexErrorCategory> Category;
} // end anonymous namespace
char IndexError::ID;
void IndexError::log(raw_ostream &OS) const {
OS << Category->message(static_cast<int>(Code)) << '\n';
std::error_code IndexError::convertToErrorCode() const {
return std::error_code(static_cast<int>(Code), *Category);
parseCrossTUIndex(StringRef IndexPath, StringRef CrossTUDir) {
std::ifstream ExternalMapFile(IndexPath);
if (!ExternalMapFile)
return llvm::make_error<IndexError>(index_error_code::missing_index_file,
llvm::StringMap<std::string> Result;
std::string Line;
unsigned LineNo = 1;
while (std::getline(ExternalMapFile, Line)) {
const size_t Pos = Line.find(" ");
if (Pos > 0 && Pos != std::string::npos) {
StringRef LineRef{Line};
StringRef LookupName = LineRef.substr(0, Pos);
if (Result.count(LookupName))
return llvm::make_error<IndexError>(
index_error_code::multiple_definitions, IndexPath.str(), LineNo);
StringRef FileName = LineRef.substr(Pos + 1);
SmallString<256> FilePath = CrossTUDir;
llvm::sys::path::append(FilePath, FileName);
Result[LookupName] = FilePath.str().str();
} else
return llvm::make_error<IndexError>(
index_error_code::invalid_index_format, IndexPath.str(), LineNo);
return Result;
createCrossTUIndexString(const llvm::StringMap<std::string> &Index) {
std::ostringstream Result;
for (const auto &E : Index)
Result << E.getKey().str() << " " << E.getValue() << '\n';
return Result.str();
bool containsConst(const VarDecl *VD, const ASTContext &ACtx) {
CanQualType CT = ACtx.getCanonicalType(VD->getType());
if (!CT.isConstQualified()) {
const RecordType *RTy = CT->getAs<RecordType>();
if (!RTy || !RTy->hasConstFields())
return false;
return true;
static bool hasBodyOrInit(const FunctionDecl *D, const FunctionDecl *&DefD) {
return D->hasBody(DefD);
static bool hasBodyOrInit(const VarDecl *D, const VarDecl *&DefD) {
return D->getAnyInitializer(DefD);
template <typename T> static bool hasBodyOrInit(const T *D) {
const T *Unused;
return hasBodyOrInit(D, Unused);
CrossTranslationUnitContext::CrossTranslationUnitContext(CompilerInstance &CI)
: Context(CI.getASTContext()), ASTStorage(CI) {}
CrossTranslationUnitContext::~CrossTranslationUnitContext() {}
CrossTranslationUnitContext::getLookupName(const NamedDecl *ND) {
SmallString<128> DeclUSR;
bool Ret = index::generateUSRForDecl(ND, DeclUSR);
if (Ret)
return {};
return std::string(DeclUSR.str());
/// Recursively visits the decls of a DeclContext, and returns one with the
/// given USR.
template <typename T>
const T *
CrossTranslationUnitContext::findDefInDeclContext(const DeclContext *DC,
StringRef LookupName) {
assert(DC && "Declaration Context must not be null");
for (const Decl *D : DC->decls()) {
const auto *SubDC = dyn_cast<DeclContext>(D);
if (SubDC)
if (const auto *ND = findDefInDeclContext<T>(SubDC, LookupName))
return ND;
const auto *ND = dyn_cast<T>(D);
const T *ResultDecl;
if (!ND || !hasBodyOrInit(ND, ResultDecl))
llvm::Optional<std::string> ResultLookupName = getLookupName(ResultDecl);
if (!ResultLookupName || *ResultLookupName != LookupName)
return ResultDecl;
return nullptr;
template <typename T>
llvm::Expected<const T *> CrossTranslationUnitContext::getCrossTUDefinitionImpl(
const T *D, StringRef CrossTUDir, StringRef IndexName,
bool DisplayCTUProgress) {
assert(D && "D is missing, bad call to this function!");
assert(!hasBodyOrInit(D) &&
"D has a body or init in current translation unit!");
const llvm::Optional<std::string> LookupName = getLookupName(D);
if (!LookupName)
return llvm::make_error<IndexError>(
llvm::Expected<ASTUnit *> ASTUnitOrError =
loadExternalAST(*LookupName, CrossTUDir, IndexName, DisplayCTUProgress);
if (!ASTUnitOrError)
return ASTUnitOrError.takeError();
ASTUnit *Unit = *ASTUnitOrError;
assert(&Unit->getFileManager() ==
const llvm::Triple &TripleTo = Context.getTargetInfo().getTriple();
const llvm::Triple &TripleFrom =
// The imported AST had been generated for a different target.
// Some parts of the triple in the loaded ASTContext can be unknown while the
// very same parts in the target ASTContext are known. Thus we check for the
// known parts only.
if (!hasEqualKnownFields(TripleTo, TripleFrom)) {
// TODO: Pass the SourceLocation of the CallExpression for more precise
// diagnostics.
return llvm::make_error<IndexError>(index_error_code::triple_mismatch,
Unit->getMainFileName(), TripleTo.str(),
const auto &LangTo = Context.getLangOpts();
const auto &LangFrom = Unit->getASTContext().getLangOpts();
// FIXME: Currenty we do not support CTU across C++ and C and across
// different dialects of C++.
if (LangTo.CPlusPlus != LangFrom.CPlusPlus) {
return llvm::make_error<IndexError>(index_error_code::lang_mismatch);
// If CPP dialects are different then return with error.
// Consider this STL code:
// template<typename _Alloc>
// struct __alloc_traits
// #if __cplusplus >= 201103L
// : std::allocator_traits<_Alloc>
// #endif
// { // ...
// };
// This class template would create ODR errors during merging the two units,
// since in one translation unit the class template has a base class, however
// in the other unit it has none.
if (LangTo.CPlusPlus11 != LangFrom.CPlusPlus11 ||
LangTo.CPlusPlus14 != LangFrom.CPlusPlus14 ||
LangTo.CPlusPlus17 != LangFrom.CPlusPlus17 ||
LangTo.CPlusPlus2a != LangFrom.CPlusPlus2a) {
return llvm::make_error<IndexError>(
TranslationUnitDecl *TU = Unit->getASTContext().getTranslationUnitDecl();
if (const T *ResultDecl = findDefInDeclContext<T>(TU, *LookupName))
return importDefinition(ResultDecl, Unit);
return llvm::make_error<IndexError>(index_error_code::failed_import);
llvm::Expected<const FunctionDecl *>
CrossTranslationUnitContext::getCrossTUDefinition(const FunctionDecl *FD,
StringRef CrossTUDir,
StringRef IndexName,
bool DisplayCTUProgress) {
return getCrossTUDefinitionImpl(FD, CrossTUDir, IndexName,
llvm::Expected<const VarDecl *>
CrossTranslationUnitContext::getCrossTUDefinition(const VarDecl *VD,
StringRef CrossTUDir,
StringRef IndexName,
bool DisplayCTUProgress) {
return getCrossTUDefinitionImpl(VD, CrossTUDir, IndexName,
void CrossTranslationUnitContext::emitCrossTUDiagnostics(const IndexError &IE) {
switch (IE.getCode()) {
case index_error_code::missing_index_file:
<< IE.getFileName();
case index_error_code::invalid_index_format:
<< IE.getFileName() << IE.getLineNum();
case index_error_code::multiple_definitions:
<< IE.getLineNum();
case index_error_code::triple_mismatch:
<< IE.getFileName() << IE.getTripleToName() << IE.getTripleFromName();
const CompilerInstance &CI)
: CI(CI) {}
CrossTranslationUnitContext::ASTFileLoader::operator()(StringRef ASTFilePath) {
// Load AST from ast-dump.
IntrusiveRefCntPtr<DiagnosticOptions> DiagOpts = new DiagnosticOptions();
TextDiagnosticPrinter *DiagClient =
new TextDiagnosticPrinter(llvm::errs(), &*DiagOpts);
IntrusiveRefCntPtr<DiagnosticIDs> DiagID(new DiagnosticIDs());
IntrusiveRefCntPtr<DiagnosticsEngine> Diags(
new DiagnosticsEngine(DiagID, &*DiagOpts, DiagClient));
return ASTUnit::LoadFromASTFile(
ASTFilePath, CI.getPCHContainerOperations()->getRawReader(),
ASTUnit::LoadEverything, Diags, CI.getFileSystemOpts());
const CompilerInstance &CI)
: FileAccessor(CI), LoadGuard(const_cast<CompilerInstance &>(CI)
->CTUImportThreshold) {}
llvm::Expected<ASTUnit *>
StringRef FileName, bool DisplayCTUProgress) {
// Try the cache first.
auto ASTCacheEntry = FileASTUnitMap.find(FileName);
if (ASTCacheEntry == FileASTUnitMap.end()) {
// Do not load if the limit is reached.
if (!LoadGuard) {
return llvm::make_error<IndexError>(
// Load the ASTUnit from the pre-dumped AST file specified by ASTFileName.
std::unique_ptr<ASTUnit> LoadedUnit = FileAccessor(FileName);
// Need the raw pointer and the unique_ptr as well.
ASTUnit *Unit = LoadedUnit.get();
// Update the cache.
FileASTUnitMap[FileName] = std::move(LoadedUnit);
if (DisplayCTUProgress)
llvm::errs() << "CTU loaded AST file: " << FileName << "\n";
return Unit;
} else {
// Found in the cache.
return ASTCacheEntry->second.get();
llvm::Expected<ASTUnit *>
StringRef FunctionName, StringRef CrossTUDir, StringRef IndexName,
bool DisplayCTUProgress) {
// Try the cache first.
auto ASTCacheEntry = NameASTUnitMap.find(FunctionName);
if (ASTCacheEntry == NameASTUnitMap.end()) {
// Load the ASTUnit from the pre-dumped AST file specified by ASTFileName.
// Ensure that the Index is loaded, as we need to search in it.
if (llvm::Error IndexLoadError =
ensureCTUIndexLoaded(CrossTUDir, IndexName))
return std::move(IndexLoadError);
// Check if there is and entry in the index for the function.
if (!NameFileMap.count(FunctionName)) {
return llvm::make_error<IndexError>(index_error_code::missing_definition);
// Search in the index for the filename where the definition of FuncitonName
// resides.
if (llvm::Expected<ASTUnit *> FoundForFile =
getASTUnitForFile(NameFileMap[FunctionName], DisplayCTUProgress)) {
// Update the cache.
NameASTUnitMap[FunctionName] = *FoundForFile;
return *FoundForFile;
} else {
return FoundForFile.takeError();
} else {
// Found in the cache.
return ASTCacheEntry->second;
StringRef FunctionName, StringRef CrossTUDir, StringRef IndexName) {
if (llvm::Error IndexLoadError = ensureCTUIndexLoaded(CrossTUDir, IndexName))
return std::move(IndexLoadError);
return NameFileMap[FunctionName];
llvm::Error CrossTranslationUnitContext::ASTUnitStorage::ensureCTUIndexLoaded(
StringRef CrossTUDir, StringRef IndexName) {
// Dont initialize if the map is filled.
if (!NameFileMap.empty())
return llvm::Error::success();
// Get the absolute path to the index file.
SmallString<256> IndexFile = CrossTUDir;
if (llvm::sys::path::is_absolute(IndexName))
IndexFile = IndexName;
llvm::sys::path::append(IndexFile, IndexName);
if (auto IndexMapping = parseCrossTUIndex(IndexFile, CrossTUDir)) {
// Initialize member map.
NameFileMap = *IndexMapping;
return llvm::Error::success();
} else {
// Error while parsing CrossTU index file.
return IndexMapping.takeError();
llvm::Expected<ASTUnit *> CrossTranslationUnitContext::loadExternalAST(
StringRef LookupName, StringRef CrossTUDir, StringRef IndexName,
bool DisplayCTUProgress) {
// FIXME: The current implementation only supports loading decls with
// a lookup name from a single translation unit. If multiple
// translation units contains decls with the same lookup name an
// error will be returned.
// Try to get the value from the heavily cached storage.
llvm::Expected<ASTUnit *> Unit = ASTStorage.getASTUnitForFunction(
LookupName, CrossTUDir, IndexName, DisplayCTUProgress);
if (!Unit)
return Unit.takeError();
// Check whether the backing pointer of the Expected is a nullptr.
if (!*Unit)
return llvm::make_error<IndexError>(
return Unit;
template <typename T>
llvm::Expected<const T *>
CrossTranslationUnitContext::importDefinitionImpl(const T *D, ASTUnit *Unit) {
assert(hasBodyOrInit(D) && "Decls to be imported should have body or init.");
assert(&D->getASTContext() == &Unit->getASTContext() &&
"ASTContext of Decl and the unit should match.");
ASTImporter &Importer = getOrCreateASTImporter(Unit);
auto ToDeclOrError = Importer.Import(D);
if (!ToDeclOrError) {
[&](const ImportError &IE) {
switch (IE.Error) {
case ImportError::NameConflict:
case ImportError::UnsupportedConstruct:
case ImportError::Unknown:
llvm_unreachable("Unknown import error happened.");
return llvm::make_error<IndexError>(index_error_code::failed_import);
auto *ToDecl = cast<T>(*ToDeclOrError);
assert(hasBodyOrInit(ToDecl) && "Imported Decl should have body or init.");
return ToDecl;
llvm::Expected<const FunctionDecl *>
CrossTranslationUnitContext::importDefinition(const FunctionDecl *FD,
ASTUnit *Unit) {
return importDefinitionImpl(FD, Unit);
llvm::Expected<const VarDecl *>
CrossTranslationUnitContext::importDefinition(const VarDecl *VD,
ASTUnit *Unit) {
return importDefinitionImpl(VD, Unit);
void CrossTranslationUnitContext::lazyInitImporterSharedSt(
TranslationUnitDecl *ToTU) {
if (!ImporterSharedSt)
ImporterSharedSt = std::make_shared<ASTImporterSharedState>(*ToTU);
ASTImporter &
CrossTranslationUnitContext::getOrCreateASTImporter(ASTUnit *Unit) {
ASTContext &From = Unit->getASTContext();
auto I = ASTUnitImporterMap.find(From.getTranslationUnitDecl());
if (I != ASTUnitImporterMap.end())
return *I->second;
ASTImporter *NewImporter = new ASTImporter(
Context, Context.getSourceManager().getFileManager(), From,
From.getSourceManager().getFileManager(), false, ImporterSharedSt);
NewImporter->setFileIDImportHandler([this, Unit](FileID ToID, FileID FromID) {
assert(ImportedFileIDs.find(ToID) == ImportedFileIDs.end() &&
"FileID already imported, should not happen.");
ImportedFileIDs[ToID] = std::make_pair(FromID, Unit);
return *NewImporter;
llvm::Optional<std::pair<SourceLocation, ASTUnit *>>
const clang::SourceLocation &ToLoc) const {
const SourceManager &SM = Context.getSourceManager();
auto DecToLoc = SM.getDecomposedLoc(ToLoc);
auto I = ImportedFileIDs.find(DecToLoc.first);
if (I == ImportedFileIDs.end())
return {};
FileID FromID = I->second.first;
clang::ASTUnit *Unit = I->second.second;
SourceLocation FromLoc =
Unit->getSourceManager().getComposedLoc(FromID, DecToLoc.second);
return std::make_pair(FromLoc, Unit);
} // namespace cross_tu
} // namespace clang