Coverage Report

Created: 2021-06-15 06:44

/Users/buildslave/jenkins/workspace/coverage/llvm-project/clang/include/clang/CrossTU/CrossTranslationUnit.h
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//===--- CrossTranslationUnit.h - -------------------------------*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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//  This file provides an interface to load binary AST dumps on demand. This
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//  feature can be utilized for tools that require cross translation unit
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//  support.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_CLANG_CROSSTU_CROSSTRANSLATIONUNIT_H
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#define LLVM_CLANG_CROSSTU_CROSSTRANSLATIONUNIT_H
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#include "clang/AST/ASTImporterSharedState.h"
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#include "clang/Analysis/MacroExpansionContext.h"
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#include "clang/Basic/LLVM.h"
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#include "llvm/ADT/DenseMap.h"
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#include "llvm/ADT/Optional.h"
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#include "llvm/ADT/SmallPtrSet.h"
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#include "llvm/ADT/StringMap.h"
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#include "llvm/Support/Error.h"
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#include "llvm/Support/Path.h"
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namespace clang {
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class CompilerInstance;
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class ASTContext;
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class ASTImporter;
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class ASTUnit;
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class DeclContext;
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class FunctionDecl;
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class VarDecl;
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class NamedDecl;
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class TranslationUnitDecl;
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namespace cross_tu {
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enum class index_error_code {
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  success = 0,
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  unspecified = 1,
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  missing_index_file,
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  invalid_index_format,
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  multiple_definitions,
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  missing_definition,
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  failed_import,
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  failed_to_get_external_ast,
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  failed_to_generate_usr,
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  triple_mismatch,
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  lang_mismatch,
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  lang_dialect_mismatch,
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  load_threshold_reached,
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  invocation_list_ambiguous,
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  invocation_list_file_not_found,
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  invocation_list_empty,
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  invocation_list_wrong_format,
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  invocation_list_lookup_unsuccessful
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};
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class IndexError : public llvm::ErrorInfo<IndexError> {
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public:
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  static char ID;
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  IndexError(index_error_code C) : Code(C), LineNo(0) {}
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  IndexError(index_error_code C, std::string FileName, int LineNo = 0)
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      : Code(C), FileName(std::move(FileName)), LineNo(LineNo) {}
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  IndexError(index_error_code C, std::string FileName, std::string TripleToName,
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             std::string TripleFromName)
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      : Code(C), FileName(std::move(FileName)),
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        TripleToName(std::move(TripleToName)),
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        TripleFromName(std::move(TripleFromName)) {}
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  void log(raw_ostream &OS) const override;
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  std::error_code convertToErrorCode() const override;
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  index_error_code getCode() const { return Code; }
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  int getLineNum() const { return LineNo; }
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  std::string getFileName() const { return FileName; }
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  std::string getTripleToName() const { return TripleToName; }
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  std::string getTripleFromName() const { return TripleFromName; }
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private:
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  index_error_code Code;
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  std::string FileName;
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  int LineNo;
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  std::string TripleToName;
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  std::string TripleFromName;
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};
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/// This function parses an index file that determines which
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/// translation unit contains which definition. The IndexPath is not prefixed
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/// with CTUDir, so an absolute path is expected for consistent results.
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///
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/// The index file format is the following:
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/// each line consists of an USR and a filepath separated by a space.
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///
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/// \return Returns a map where the USR is the key and the filepath is the value
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///         or an error.
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llvm::Expected<llvm::StringMap<std::string>>
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parseCrossTUIndex(StringRef IndexPath);
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std::string createCrossTUIndexString(const llvm::StringMap<std::string> &Index);
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using InvocationListTy = llvm::StringMap<llvm::SmallVector<std::string, 32>>;
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/// Parse the YAML formatted invocation list file content \p FileContent.
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/// The format is expected to be a mapping from from absolute source file
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/// paths in the filesystem to a list of command-line parts, which
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/// constitute the invocation needed to compile that file. That invocation
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/// will be used to produce the AST of the TU.
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llvm::Expected<InvocationListTy> parseInvocationList(
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    StringRef FileContent,
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    llvm::sys::path::Style PathStyle = llvm::sys::path::Style::posix);
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// Returns true if the variable or any field of a record variable is const.
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bool containsConst(const VarDecl *VD, const ASTContext &ACtx);
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/// This class is used for tools that requires cross translation
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///        unit capability.
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///
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/// This class can load definitions from external AST sources.
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/// The loaded definition will be merged back to the original AST using the
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/// AST Importer.
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/// In order to use this class, an index file is required that describes
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/// the locations of the AST files for each definition.
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///
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/// Note that this class also implements caching.
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class CrossTranslationUnitContext {
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public:
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  CrossTranslationUnitContext(CompilerInstance &CI);
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  ~CrossTranslationUnitContext();
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  /// This function loads a function or variable definition from an
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  ///        external AST file and merges it into the original AST.
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  ///
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  /// This method should only be used on functions that have no definitions or
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  /// variables that have no initializer in
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  /// the current translation unit. A function definition with the same
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  /// declaration will be looked up in the index file which should be in the
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  /// \p CrossTUDir directory, called \p IndexName. In case the declaration is
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  /// found in the index the corresponding AST will be loaded and the
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  /// definition will be merged into the original AST using the AST Importer.
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  ///
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  /// \return The declaration with the definition will be returned.
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  /// If no suitable definition is found in the index file or multiple
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  /// definitions found error will be returned.
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  ///
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  /// Note that the AST files should also be in the \p CrossTUDir.
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  llvm::Expected<const FunctionDecl *>
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  getCrossTUDefinition(const FunctionDecl *FD, StringRef CrossTUDir,
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                       StringRef IndexName, bool DisplayCTUProgress = false);
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  llvm::Expected<const VarDecl *>
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  getCrossTUDefinition(const VarDecl *VD, StringRef CrossTUDir,
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                       StringRef IndexName, bool DisplayCTUProgress = false);
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  /// This function loads a definition from an external AST file.
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  ///
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  /// A definition with the same declaration will be looked up in the
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  /// index file which should be in the \p CrossTUDir directory, called
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  /// \p IndexName. In case the declaration is found in the index the
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  /// corresponding AST will be loaded. If the number of TUs imported
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  /// reaches \p CTULoadTreshold, no loading is performed.
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  ///
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  /// \return Returns a pointer to the ASTUnit that contains the definition of
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  /// the looked up name or an Error.
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  /// The returned pointer is never a nullptr.
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  ///
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  /// Note that the AST files should also be in the \p CrossTUDir.
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  llvm::Expected<ASTUnit *> loadExternalAST(StringRef LookupName,
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                                            StringRef CrossTUDir,
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                                            StringRef IndexName,
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                                            bool DisplayCTUProgress = false);
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  /// This function merges a definition from a separate AST Unit into
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  ///        the current one which was created by the compiler instance that
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  ///        was passed to the constructor.
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  ///
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  /// \return Returns the resulting definition or an error.
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  llvm::Expected<const FunctionDecl *> importDefinition(const FunctionDecl *FD,
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                                                        ASTUnit *Unit);
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  llvm::Expected<const VarDecl *> importDefinition(const VarDecl *VD,
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                                                   ASTUnit *Unit);
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  /// Get a name to identify a named decl.
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  static llvm::Optional<std::string> getLookupName(const NamedDecl *ND);
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  /// Emit diagnostics for the user for potential configuration errors.
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  void emitCrossTUDiagnostics(const IndexError &IE);
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  /// Returns the MacroExpansionContext for the imported TU to which the given
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  /// source-location corresponds.
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  /// \p ToLoc Source location in the imported-to AST.
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  /// \note If any error happens such as \p ToLoc is a non-imported
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  ///       source-location, empty is returned.
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  /// \note Macro expansion tracking for imported TUs is not implemented yet.
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  ///       It returns empty unconditionally.
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  llvm::Optional<clang::MacroExpansionContext>
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  getMacroExpansionContextForSourceLocation(
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      const clang::SourceLocation &ToLoc) const;
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private:
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  void lazyInitImporterSharedSt(TranslationUnitDecl *ToTU);
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  ASTImporter &getOrCreateASTImporter(ASTUnit *Unit);
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  template <typename T>
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  llvm::Expected<const T *> getCrossTUDefinitionImpl(const T *D,
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                                                     StringRef CrossTUDir,
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                                                     StringRef IndexName,
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                                                     bool DisplayCTUProgress);
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  template <typename T>
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  const T *findDefInDeclContext(const DeclContext *DC,
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                                StringRef LookupName);
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  template <typename T>
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  llvm::Expected<const T *> importDefinitionImpl(const T *D, ASTUnit *Unit);
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  using ImporterMapTy =
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      llvm::DenseMap<TranslationUnitDecl *, std::unique_ptr<ASTImporter>>;
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  ImporterMapTy ASTUnitImporterMap;
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  ASTContext &Context;
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  std::shared_ptr<ASTImporterSharedState> ImporterSharedSt;
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  using LoadResultTy = llvm::Expected<std::unique_ptr<ASTUnit>>;
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  /// Loads ASTUnits from AST-dumps or source-files.
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  class ASTLoader {
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  public:
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    ASTLoader(CompilerInstance &CI, StringRef CTUDir,
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              StringRef InvocationListFilePath);
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    /// Load the ASTUnit by its identifier found in the index file. If the
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    /// indentifier is suffixed with '.ast' it is considered a dump. Otherwise
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    /// it is treated as source-file, and on-demand parsed. Relative paths are
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    /// prefixed with CTUDir.
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    LoadResultTy load(StringRef Identifier);
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    /// Lazily initialize the invocation list information, which is needed for
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    /// on-demand parsing.
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    llvm::Error lazyInitInvocationList();
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  private:
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    /// The style used for storage and lookup of filesystem paths.
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    /// Defaults to posix.
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    const llvm::sys::path::Style PathStyle = llvm::sys::path::Style::posix;
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    /// Loads an AST from a pch-dump.
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    LoadResultTy loadFromDump(StringRef Identifier);
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    /// Loads an AST from a source-file.
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    LoadResultTy loadFromSource(StringRef Identifier);
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    CompilerInstance &CI;
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    StringRef CTUDir;
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    /// The path to the file containing the invocation list, which is in YAML
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    /// format, and contains a mapping from source files to compiler invocations
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    /// that produce the AST used for analysis.
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    StringRef InvocationListFilePath;
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    /// In case of on-demand parsing, the invocations for parsing the source
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    /// files is stored.
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    llvm::Optional<InvocationListTy> InvocationList;
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    index_error_code PreviousParsingResult = index_error_code::success;
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  };
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  /// Maintain number of AST loads and check for reaching the load limit.
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  class ASTLoadGuard {
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  public:
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    ASTLoadGuard(unsigned Limit) : Limit(Limit) {}
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    /// Indicates, whether a new load operation is permitted, it is within the
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    /// threshold.
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    operator bool() const { return Count < Limit; }
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    /// Tell that a new AST was loaded successfully.
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    void indicateLoadSuccess() { ++Count; }
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  private:
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    /// The number of ASTs actually imported.
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    unsigned Count{0u};
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    /// The limit (threshold) value for number of loaded ASTs.
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    const unsigned Limit;
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  };
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  /// Storage and load of ASTUnits, cached access, and providing searchability
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  /// are the concerns of ASTUnitStorage class.
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  class ASTUnitStorage {
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  public:
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    ASTUnitStorage(CompilerInstance &CI);
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    /// Loads an ASTUnit for a function.
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    ///
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    /// \param FunctionName USR name of the function.
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    /// \param CrossTUDir Path to the directory used to store CTU related files.
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    /// \param IndexName Name of the file inside \p CrossTUDir which maps
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    /// function USR names to file paths. These files contain the corresponding
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    /// AST-dumps.
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    /// \param DisplayCTUProgress Display a message about loading new ASTs.
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    ///
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    /// \return An Expected instance which contains the ASTUnit pointer or the
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    /// error occured during the load.
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    llvm::Expected<ASTUnit *> getASTUnitForFunction(StringRef FunctionName,
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                                                    StringRef CrossTUDir,
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                                                    StringRef IndexName,
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                                                    bool DisplayCTUProgress);
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    /// Identifies the path of the file which can be used to load the ASTUnit
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    /// for a given function.
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    ///
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    /// \param FunctionName USR name of the function.
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    /// \param CrossTUDir Path to the directory used to store CTU related files.
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    /// \param IndexName Name of the file inside \p CrossTUDir which maps
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    /// function USR names to file paths. These files contain the corresponding
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    /// AST-dumps.
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    ///
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    /// \return An Expected instance containing the filepath.
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    llvm::Expected<std::string> getFileForFunction(StringRef FunctionName,
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                                                   StringRef CrossTUDir,
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                                                   StringRef IndexName);
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  private:
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    llvm::Error ensureCTUIndexLoaded(StringRef CrossTUDir, StringRef IndexName);
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    llvm::Expected<ASTUnit *> getASTUnitForFile(StringRef FileName,
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                                                bool DisplayCTUProgress);
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    template <typename... T> using BaseMapTy = llvm::StringMap<T...>;
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    using OwningMapTy = BaseMapTy<std::unique_ptr<clang::ASTUnit>>;
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    using NonOwningMapTy = BaseMapTy<clang::ASTUnit *>;
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    OwningMapTy FileASTUnitMap;
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    NonOwningMapTy NameASTUnitMap;
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    using IndexMapTy = BaseMapTy<std::string>;
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    IndexMapTy NameFileMap;
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    /// Loads the AST based on the identifier found in the index.
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    ASTLoader Loader;
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    /// Limit the number of loaded ASTs. It is used to limit the  memory usage
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    /// of the CrossTranslationUnitContext. The ASTUnitStorage has the
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    /// information whether the AST to load is actually loaded or returned from
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    /// cache. This information is needed to maintain the counter.
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    ASTLoadGuard LoadGuard;
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  };
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  ASTUnitStorage ASTStorage;
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};
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} // namespace cross_tu
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} // namespace clang
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#endif // LLVM_CLANG_CROSSTU_CROSSTRANSLATIONUNIT_H