r367829 - [CrossTU][NFCI] Refactor loadExternalAST function

Nico Weber via cfe-commits cfe-commits at lists.llvm.org
Mon Aug 5 07:03:56 PDT 2019


The msan bot doesn't like this, it reports an uninitialized read a
t clang/lib/CrossTU/CrossTranslationUnit.cpp :

http://lab.llvm.org:8011/builders/sanitizer-x86_64-linux-fast/builds/34087/steps/check-clang%20msan/logs/stdio

********************
Testing: 0
FAIL: Clang :: Analysis/ctu-unknown-parts-in-triples.cpp (492 of 15321)
******************** TEST 'Clang ::
Analysis/ctu-unknown-parts-in-triples.cpp' FAILED ********************
Script:
--
: 'RUN: at line 4';   rm -rf
/b/sanitizer-x86_64-linux-fast/build/llvm_build_msan/tools/clang/test/Analysis/Output/ctu-unknown-parts-in-triples.cpp.tmp
&& mkdir
/b/sanitizer-x86_64-linux-fast/build/llvm_build_msan/tools/clang/test/Analysis/Output/ctu-unknown-parts-in-triples.cpp.tmp
: 'RUN: at line 5';   mkdir -p
/b/sanitizer-x86_64-linux-fast/build/llvm_build_msan/tools/clang/test/Analysis/Output/ctu-unknown-parts-in-triples.cpp.tmp/ctudir
: 'RUN: at line 6';
/b/sanitizer-x86_64-linux-fast/build/llvm_build_msan/bin/clang -cc1
-internal-isystem
/b/sanitizer-x86_64-linux-fast/build/llvm_build_msan/lib/clang/10.0.0/include
-nostdsysteminc -triple x86_64-pc-linux-gnu    -emit-pch -o
/b/sanitizer-x86_64-linux-fast/build/llvm_build_msan/tools/clang/test/Analysis/Output/ctu-unknown-parts-in-triples.cpp.tmp/ctudir/ctu-other.cpp.ast
/b/sanitizer-x86_64-linux-fast/build/llvm/tools/clang/test/Analysis/Inputs/ctu-other.cpp
: 'RUN: at line 8';   cp
/b/sanitizer-x86_64-linux-fast/build/llvm/tools/clang/test/Analysis/Inputs/ctu-other.cpp.externalDefMap.txt
/b/sanitizer-x86_64-linux-fast/build/llvm_build_msan/tools/clang/test/Analysis/Output/ctu-unknown-parts-in-triples.cpp.tmp/ctudir/externalDefMap.txt
: 'RUN: at line 9';
/b/sanitizer-x86_64-linux-fast/build/llvm_build_msan/bin/clang -cc1
-internal-isystem
/b/sanitizer-x86_64-linux-fast/build/llvm_build_msan/lib/clang/10.0.0/include
-nostdsysteminc -analyze -analyzer-constraints=range -triple
x86_64-unknown-linux-gnu    -analyzer-checker=core,debug.ExprInspection
 -analyzer-config experimental-enable-naive-ctu-analysis=true
 -analyzer-config
ctu-dir=/b/sanitizer-x86_64-linux-fast/build/llvm_build_msan/tools/clang/test/Analysis/Output/ctu-unknown-parts-in-triples.cpp.tmp/ctudir
   -Werror=ctu    -verify
/b/sanitizer-x86_64-linux-fast/build/llvm/tools/clang/test/Analysis/ctu-unknown-parts-in-triples.cpp
--
Exit Code: 77

Command Output (stderr):
--
==5072==WARNING: MemorySanitizer: use-of-uninitialized-value
    #0 0xb05c3c4 in
clang::cross_tu::CrossTranslationUnitContext::loadExternalAST(llvm::StringRef,
llvm::StringRef, llvm::StringRef, bool)
/b/sanitizer-x86_64-linux-fast/build/llvm/tools/clang/lib/CrossTU/CrossTranslationUnit.cpp:467:7
    #1 0xb053a98 in llvm::Expected<clang::FunctionDecl const*>
clang::cross_tu::CrossTranslationUnitContext::getCrossTUDefinitionImpl<clang::FunctionDecl>(clang::FunctionDecl
const*, llvm::StringRef, llvm::StringRef, bool)
/b/sanitizer-x86_64-linux-fast/build/llvm/tools/clang/lib/CrossTU/CrossTranslationUnit.cpp:241:7
    #2 0xb053466 in
clang::cross_tu::CrossTranslationUnitContext::getCrossTUDefinition(clang::FunctionDecl
const*, llvm::StringRef, llvm::StringRef, bool)
/b/sanitizer-x86_64-linux-fast/build/llvm/tools/clang/lib/CrossTU/CrossTranslationUnit.cpp:307:10
    #3 0xadb69f5 in clang::ento::AnyFunctionCall::getRuntimeDefinition()
const
/b/sanitizer-x86_64-linux-fast/build/llvm/tools/clang/lib/StaticAnalyzer/Core/CallEvent.cpp:575:14

On Mon, Aug 5, 2019 at 7:05 AM Endre Fulop via cfe-commits <
cfe-commits at lists.llvm.org> wrote:

> Author: gamesh411
> Date: Mon Aug  5 04:06:41 2019
> New Revision: 367829
>
> URL: http://llvm.org/viewvc/llvm-project?rev=367829&view=rev
> Log:
> [CrossTU][NFCI] Refactor loadExternalAST function
>
> Summary:
> Refactor loadExternalAST method of CrossTranslationUnitContext in order to
> reduce maintenance burden and so that features are easier to add in the
> future.
>
> Reviewers: martong
>
> Subscribers: rnkovacs, dkrupp, Szelethus, cfe-commits
>
> Tags: #clang
>
> Differential Revision: https://reviews.llvm.org/D64753
>
> Modified:
>     cfe/trunk/include/clang/CrossTU/CrossTranslationUnit.h
>     cfe/trunk/lib/CrossTU/CrossTranslationUnit.cpp
>
> Modified: cfe/trunk/include/clang/CrossTU/CrossTranslationUnit.h
> URL:
> http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/CrossTU/CrossTranslationUnit.h?rev=367829&r1=367828&r2=367829&view=diff
>
> ==============================================================================
> --- cfe/trunk/include/clang/CrossTU/CrossTranslationUnit.h (original)
> +++ cfe/trunk/include/clang/CrossTU/CrossTranslationUnit.h Mon Aug  5
> 04:06:41 2019
> @@ -192,11 +192,11 @@ private:
>    template <typename T>
>    llvm::Expected<const T *> importDefinitionImpl(const T *D, ASTUnit
> *Unit);
>
> -  llvm::StringMap<std::unique_ptr<clang::ASTUnit>> FileASTUnitMap;
> -  llvm::StringMap<clang::ASTUnit *> NameASTUnitMap;
> -  llvm::StringMap<std::string> NameFileMap;
> -  llvm::DenseMap<TranslationUnitDecl *, std::unique_ptr<ASTImporter>>
> -      ASTUnitImporterMap;
> +  using ImporterMapTy =
> +      llvm::DenseMap<TranslationUnitDecl *, std::unique_ptr<ASTImporter>>;
> +
> +  ImporterMapTy ASTUnitImporterMap;
> +
>    CompilerInstance &CI;
>    ASTContext &Context;
>    std::shared_ptr<ASTImporterSharedState> ImporterSharedSt;
> @@ -209,10 +209,105 @@ private:
>    /// imported the FileID.
>    ImportedFileIDMap ImportedFileIDs;
>
> +  /// Functor for loading ASTUnits from AST-dump files.
> +  class ASTFileLoader {
> +  public:
> +    ASTFileLoader(const CompilerInstance &CI);
> +    std::unique_ptr<ASTUnit> operator()(StringRef ASTFilePath);
> +
> +  private:
> +    const CompilerInstance &CI;
> +  };
> +
> +  /// Storage for ASTUnits, cached access, and providing searchability
> are the
> +  /// concerns of ASTUnitStorage class.
> +  class ASTUnitStorage {
> +  public:
> +    ASTUnitStorage(const CompilerInstance &CI);
> +    /// Loads an ASTUnit for a function.
> +    ///
> +    /// \param FuncitionName USR name of the function.
> +    /// \param CrossTUDir Path to the directory used to store CTU related
> files.
> +    /// \param IndexName Name of the file inside \p CrossTUDir which maps
> +    /// function USR names to file paths. These files contain the
> corresponding
> +    /// AST-dumps.
> +    ///
> +    /// \return An Expected instance which contains the ASTUnit pointer
> or the
> +    /// error occured during the load.
> +    llvm::Expected<ASTUnit *> getASTUnitForFunction(StringRef
> FunctionName,
> +                                                    StringRef CrossTUDir,
> +                                                    StringRef IndexName);
> +    /// Identifies the path of the file which can be used to load the
> ASTUnit
> +    /// for a given function.
> +    ///
> +    /// \param FuncitionName USR name of the function.
> +    /// \param CrossTUDir Path to the directory used to store CTU related
> files.
> +    /// \param IndexName Name of the file inside \p CrossTUDir which maps
> +    /// function USR names to file paths. These files contain the
> corresponding
> +    /// AST-dumps.
> +    ///
> +    /// \return An Expected instance containing the filepath.
> +    llvm::Expected<std::string> getFileForFunction(StringRef FunctionName,
> +                                                   StringRef CrossTUDir,
> +                                                   StringRef IndexName);
> +
> +  private:
> +    llvm::Error ensureCTUIndexLoaded(StringRef CrossTUDir, StringRef
> IndexName);
> +    llvm::Expected<ASTUnit *> getASTUnitForFile(StringRef FileName);
> +
> +    template <typename... T> using BaseMapTy = llvm::StringMap<T...>;
> +    using OwningMapTy = BaseMapTy<std::unique_ptr<clang::ASTUnit>>;
> +    using NonOwningMapTy = BaseMapTy<clang::ASTUnit *>;
> +
> +    OwningMapTy FileASTUnitMap;
> +    NonOwningMapTy NameASTUnitMap;
> +
> +    using IndexMapTy = BaseMapTy<std::string>;
> +    IndexMapTy NameFileMap;
> +
> +    ASTFileLoader FileAccessor;
> +  };
> +
> +  ASTUnitStorage ASTStorage;
> +
>    /// \p CTULoadTreshold should serve as an upper limit to the number of
> TUs
>    /// imported in order to reduce the memory footprint of CTU analysis.
>    const unsigned CTULoadThreshold;
> -  unsigned NumASTLoaded{0u};
> +
> +  /// The number successfully loaded ASTs. Used to indicate, and  - with
> the
> +  /// appropriate threshold value - limit the  memory usage of the
> +  /// CrossTranslationUnitContext.
> +  unsigned NumASTLoaded;
> +
> +  /// RAII counter to signal 'threshold reached' condition, and to
> increment the
> +  /// NumASTLoaded counter upon a successful load.
> +  class LoadGuard {
> +  public:
> +    LoadGuard(unsigned Limit, unsigned &Counter)
> +        : Counter(Counter), Enabled(Counter < Limit){};
> +    ~LoadGuard() {
> +      if (StoreSuccess)
> +        ++Counter;
> +    }
> +    /// Flag the LoadGuard instance as successful, meaning that the load
> +    /// operation succeeded, and the memory footprint of the AST storage
> +    /// actually increased. In this case, \p Counter should be
> incremented upon
> +    /// destruction.
> +    void storedSuccessfully() { StoreSuccess = true; }
> +    /// Indicates, whether a new load operation is permitted, it is
> within the
> +    /// threshold.
> +    operator bool() const { return Enabled; };
> +
> +  private:
> +    /// The number of ASTs actually imported. LoadGuard does not own the
> +    /// counter, just uses on given to it at construction time.
> +    unsigned &Counter;
> +    /// Indicates whether a load operation can begin, which is equivalent
> to the
> +    /// 'threshold not reached' condition.
> +    bool Enabled;
> +    /// Shows the state of the current load operation.
> +    bool StoreSuccess;
> +  };
>  };
>
>  } // namespace cross_tu
>
> Modified: cfe/trunk/lib/CrossTU/CrossTranslationUnit.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CrossTU/CrossTranslationUnit.cpp?rev=367829&r1=367828&r2=367829&view=diff
>
> ==============================================================================
> --- cfe/trunk/lib/CrossTU/CrossTranslationUnit.cpp (original)
> +++ cfe/trunk/lib/CrossTU/CrossTranslationUnit.cpp Mon Aug  5 04:06:41 2019
> @@ -188,7 +188,7 @@ template <typename T> static bool hasBod
>  }
>
>  CrossTranslationUnitContext::CrossTranslationUnitContext(CompilerInstance
> &CI)
> -    : CI(CI), Context(CI.getASTContext()),
> +    : CI(CI), Context(CI.getASTContext()), ASTStorage(CI),
>        CTULoadThreshold(CI.getAnalyzerOpts()->CTUImportThreshold) {}
>
>  CrossTranslationUnitContext::~CrossTranslationUnitContext() {}
> @@ -237,8 +237,8 @@ llvm::Expected<const T *> CrossTranslati
>    if (LookupName.empty())
>      return llvm::make_error<IndexError>(
>          index_error_code::failed_to_generate_usr);
> -  llvm::Expected<ASTUnit *> ASTUnitOrError = loadExternalAST(
> -      LookupName, CrossTUDir, IndexName, DisplayCTUProgress);
> +  llvm::Expected<ASTUnit *> ASTUnitOrError =
> +      loadExternalAST(LookupName, CrossTUDir, IndexName,
> DisplayCTUProgress);
>    if (!ASTUnitOrError)
>      return ASTUnitOrError.takeError();
>    ASTUnit *Unit = *ASTUnitOrError;
> @@ -340,6 +340,118 @@ void CrossTranslationUnitContext::emitCr
>    }
>  }
>
> +CrossTranslationUnitContext::ASTFileLoader::ASTFileLoader(
> +    const CompilerInstance &CI)
> +    : CI(CI) {}
> +
> +std::unique_ptr<ASTUnit>
> +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());
> +}
> +
> +CrossTranslationUnitContext::ASTUnitStorage::ASTUnitStorage(
> +    const CompilerInstance &CI)
> +    : FileAccessor(CI) {}
> +
> +llvm::Expected<ASTUnit *>
> +CrossTranslationUnitContext::ASTUnitStorage::getASTUnitForFile(StringRef
> FileName) {
> +  // Try the cache first.
> +  auto ASTCacheEntry = FileASTUnitMap.find(FileName);
> +  if (ASTCacheEntry == FileASTUnitMap.end()) {
> +    // 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);
> +    return Unit;
> +
> +  } else {
> +    // Found in the cache.
> +    return ASTCacheEntry->second.get();
> +  }
> +}
> +
> +llvm::Expected<ASTUnit *>
> +CrossTranslationUnitContext::ASTUnitStorage::getASTUnitForFunction(
> +    StringRef FunctionName, StringRef CrossTUDir, StringRef IndexName) {
> +  // 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)) {
> +      ++NumNotInOtherTU;
> +      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])) {
> +
> +      // Update the cache.
> +      NameASTUnitMap[FunctionName] = *FoundForFile;
> +      return *FoundForFile;
> +
> +    } else {
> +      return FoundForFile.takeError();
> +    }
> +  } else {
> +    // Found in the cache.
> +    return ASTCacheEntry->second;
> +  }
> +}
> +
> +llvm::Expected<std::string>
> +CrossTranslationUnitContext::ASTUnitStorage::getFileForFunction(
> +    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;
> +  else
> +    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) {
> @@ -348,64 +460,41 @@ llvm::Expected<ASTUnit *> CrossTranslati
>    //        translation units contains decls with the same lookup name an
>    //        error will be returned.
>
> -  if (NumASTLoaded >= CTULoadThreshold) {
> +  // RAII incrementing counter is used to count successful loads.
> +  LoadGuard LoadOperation(CTULoadThreshold, NumASTLoaded);
> +
> +  // If import threshold is reached, don't import anything.
> +  if (!LoadOperation) {
>      ++NumASTLoadThresholdReached;
>      return llvm::make_error<IndexError>(
>          index_error_code::load_threshold_reached);
>    }
>
> -  ASTUnit *Unit = nullptr;
> -  auto NameUnitCacheEntry = NameASTUnitMap.find(LookupName);
> -  if (NameUnitCacheEntry == NameASTUnitMap.end()) {
> -    if (NameFileMap.empty()) {
> -      SmallString<256> IndexFile = CrossTUDir;
> -      if (llvm::sys::path::is_absolute(IndexName))
> -        IndexFile = IndexName;
> -      else
> -        llvm::sys::path::append(IndexFile, IndexName);
> -      llvm::Expected<llvm::StringMap<std::string>> IndexOrErr =
> -          parseCrossTUIndex(IndexFile, CrossTUDir);
> -      if (IndexOrErr)
> -        NameFileMap = *IndexOrErr;
> -      else
> -        return IndexOrErr.takeError();
> -    }
> +  // Try to get the value from the heavily cached storage.
> +  llvm::Expected<ASTUnit *> Unit =
> +      ASTStorage.getASTUnitForFunction(LookupName, CrossTUDir, IndexName);
>
> -    auto It = NameFileMap.find(LookupName);
> -    if (It == NameFileMap.end()) {
> -      ++NumNotInOtherTU;
> -      return
> llvm::make_error<IndexError>(index_error_code::missing_definition);
> -    }
> -    StringRef ASTFileName = It->second;
> -    auto ASTCacheEntry = FileASTUnitMap.find(ASTFileName);
> -    if (ASTCacheEntry == FileASTUnitMap.end()) {
> -      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));
> -
> -      std::unique_ptr<ASTUnit> LoadedUnit(ASTUnit::LoadFromASTFile(
> -          ASTFileName, CI.getPCHContainerOperations()->getRawReader(),
> -          ASTUnit::LoadEverything, Diags, CI.getFileSystemOpts()));
> -      Unit = LoadedUnit.get();
> -      FileASTUnitMap[ASTFileName] = std::move(LoadedUnit);
> -      ++NumASTLoaded;
> -      if (DisplayCTUProgress) {
> -        llvm::errs() << "CTU loaded AST file: "
> -                     << ASTFileName << "\n";
> -      }
> -    } else {
> -      Unit = ASTCacheEntry->second.get();
> -    }
> -    NameASTUnitMap[LookupName] = Unit;
> -  } else {
> -    Unit = NameUnitCacheEntry->second;
> -  }
>    if (!Unit)
> +    return Unit.takeError();
> +
> +  // Check whether the backing pointer of the Expected is a nullptr.
> +  if (!*Unit)
>      return llvm::make_error<IndexError>(
>          index_error_code::failed_to_get_external_ast);
> +
> +  // The backing pointer is not null, loading was successful. If anything
> goes
> +  // wrong from this point on, the AST is already stored, so the load
> part is
> +  // finished.
> +  LoadOperation.storedSuccessfully();
> +
> +  if (DisplayCTUProgress) {
> +    if (llvm::Expected<std::string> FileName =
> +            ASTStorage.getFileForFunction(LookupName, CrossTUDir,
> IndexName))
> +      llvm::errs() << "CTU loaded AST file: " << *FileName << "\n";
> +    else
> +      return FileName.takeError();
> +  }
> +
>    return Unit;
>  }
>
>
>
> _______________________________________________
> cfe-commits mailing list
> cfe-commits at lists.llvm.org
> https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
>
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