Coverage Report

Created: 2021-08-24 07:12

/Users/buildslave/jenkins/workspace/coverage/llvm-project/clang/include/clang/AST/ASTImporter.h
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//===- ASTImporter.h - Importing ASTs from other Contexts -------*- 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 defines the ASTImporter class which imports AST nodes from one
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//  context into another context.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_CLANG_AST_ASTIMPORTER_H
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#define LLVM_CLANG_AST_ASTIMPORTER_H
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#include "clang/AST/APValue.h"
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#include "clang/AST/DeclBase.h"
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#include "clang/AST/DeclarationName.h"
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#include "clang/AST/ExprCXX.h"
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#include "clang/AST/NestedNameSpecifier.h"
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#include "clang/AST/TemplateName.h"
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#include "clang/AST/Type.h"
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#include "clang/Basic/Diagnostic.h"
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#include "clang/Basic/IdentifierTable.h"
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#include "clang/Basic/LLVM.h"
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#include "clang/Basic/SourceLocation.h"
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#include "llvm/ADT/DenseMap.h"
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#include "llvm/ADT/DenseSet.h"
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#include "llvm/ADT/Optional.h"
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#include "llvm/ADT/SmallVector.h"
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#include "llvm/Support/Error.h"
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#include <utility>
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namespace clang {
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class ASTContext;
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class ASTImporterSharedState;
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class Attr;
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class CXXBaseSpecifier;
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class CXXCtorInitializer;
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class Decl;
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class DeclContext;
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class Expr;
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class FileManager;
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class NamedDecl;
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class Stmt;
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class TagDecl;
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class TranslationUnitDecl;
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class TypeSourceInfo;
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  class ImportError : public llvm::ErrorInfo<ImportError> {
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  public:
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    /// \brief Kind of error when importing an AST component.
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    enum ErrorKind {
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        NameConflict, /// Naming ambiguity (likely ODR violation).
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        UnsupportedConstruct, /// Not supported node or case.
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        Unknown /// Other error.
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    };
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    ErrorKind Error;
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    static char ID;
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883
    ImportError() : Error(Unknown) {}
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4.52k
    ImportError(const ImportError &Other) : Error(Other.Error) {}
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1.00k
    ImportError &operator=(const ImportError &Other) {
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1.00k
      Error = Other.Error;
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1.00k
      return *this;
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1.00k
    }
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565
    ImportError(ErrorKind Error) : Error(Error) { }
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    std::string toString() const;
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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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  };
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  // \brief Returns with a list of declarations started from the canonical decl
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  // then followed by subsequent decls in the translation unit.
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  // This gives a canonical list for each entry in the redecl chain.
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  // `Decl::redecls()` gives a list of decls which always start from the
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  // previous decl and the next item is actually the previous item in the order
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  // of source locations.  Thus, `Decl::redecls()` gives different lists for
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  // the different entries in a given redecl chain.
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  llvm::SmallVector<Decl*, 2> getCanonicalForwardRedeclChain(Decl* D);
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  /// Imports selected nodes from one AST context into another context,
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  /// merging AST nodes where appropriate.
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  class ASTImporter {
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    friend class ASTNodeImporter;
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  public:
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    using NonEquivalentDeclSet = llvm::DenseSet<std::pair<Decl *, Decl *>>;
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    using ImportedCXXBaseSpecifierMap =
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        llvm::DenseMap<const CXXBaseSpecifier *, CXXBaseSpecifier *>;
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    enum class ODRHandlingType { Conservative, Liberal };
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    // An ImportPath is the list of the AST nodes which we visit during an
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    // Import call.
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    // If node `A` depends on node `B` then the path contains an `A`->`B` edge.
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    // From the call stack of the import functions we can read the very same
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    // path.
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    //
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    // Now imagine the following AST, where the `->` represents dependency in
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    // therms of the import.
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    // ```
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    // A->B->C->D
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    //    `->E
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    // ```
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    // We would like to import A.
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    // The import behaves like a DFS, so we will visit the nodes in this order:
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    // ABCDE.
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    // During the visitation we will have the following ImportPaths:
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    // ```
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    // A
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    // AB
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    // ABC
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    // ABCD
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    // ABC
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    // AB
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    // ABE
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    // AB
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    // A
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    // ```
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    // If during the visit of E there is an error then we set an error for E,
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    // then as the call stack shrinks for B, then for A:
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    // ```
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    // A
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    // AB
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    // ABC
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    // ABCD
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    // ABC
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    // AB
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    // ABE // Error! Set an error to E
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    // AB  // Set an error to B
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    // A   // Set an error to A
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    // ```
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    // However, during the import we could import C and D without any error and
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    // they are independent from A,B and E.
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    // We must not set up an error for C and D.
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    // So, at the end of the import we have an entry in `ImportDeclErrors` for
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    // A,B,E but not for C,D.
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    //
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    // Now what happens if there is a cycle in the import path?
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    // Let's consider this AST:
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    // ```
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    // A->B->C->A
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    //    `->E
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    // ```
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    // During the visitation we will have the below ImportPaths and if during
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    // the visit of E there is an error then we will set up an error for E,B,A.
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    // But what's up with C?
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    // ```
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    // A
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    // AB
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    // ABC
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    // ABCA
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    // ABC
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    // AB
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    // ABE // Error! Set an error to E
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    // AB  // Set an error to B
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    // A   // Set an error to A
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    // ```
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    // This time we know that both B and C are dependent on A.
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    // This means we must set up an error for C too.
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    // As the call stack reverses back we get to A and we must set up an error
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    // to all nodes which depend on A (this includes C).
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    // But C is no longer on the import path, it just had been previously.
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    // Such situation can happen only if during the visitation we had a cycle.
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    // If we didn't have any cycle, then the normal way of passing an Error
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    // object through the call stack could handle the situation.
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    // This is why we must track cycles during the import process for each
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    // visited declaration.
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    class ImportPathTy {
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    public:
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      using VecTy = llvm::SmallVector<Decl *, 32>;
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9.27M
      void push(Decl *D) {
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9.27M
        Nodes.push_back(D);
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9.27M
        ++Aux[D];
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9.27M
      }
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9.27M
      void pop() {
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9.27M
        if (Nodes.empty())
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0
          return;
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9.27M
        --Aux[Nodes.back()];
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9.27M
        Nodes.pop_back();
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9.27M
      }
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      /// Returns true if the last element can be found earlier in the path.
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7.21M
      bool hasCycleAtBack() const {
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7.21M
        auto Pos = Aux.find(Nodes.back());
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7.21M
        return Pos != Aux.end() && Pos->second > 1;
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7.21M
      }
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      using Cycle = llvm::iterator_range<VecTy::const_reverse_iterator>;
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499k
      Cycle getCycleAtBack() const {
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499k
        assert(Nodes.size() >= 2);
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0
        return Cycle(Nodes.rbegin(),
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499k
                     std::find(Nodes.rbegin() + 1, Nodes.rend(), Nodes.back()) +
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499k
                         1);
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      }
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      /// Returns the copy of the cycle.
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      VecTy copyCycleAtBack() const {
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        auto R = getCycleAtBack();
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        return VecTy(R.begin(), R.end());
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      }
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    private:
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      // All nodes of the path.
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      VecTy Nodes;
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      // Auxiliary container to be able to answer "Do we have a cycle ending
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      // at last element?" as fast as possible.
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      // We count each Decl's occurrence over the path.
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      llvm::SmallDenseMap<Decl *, int, 32> Aux;
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    };
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  private:
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    std::shared_ptr<ASTImporterSharedState> SharedState = nullptr;
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    /// The path which we go through during the import of a given AST node.
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    ImportPathTy ImportPath;
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    /// Sometimes we have to save some part of an import path, so later we can
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    /// set up properties to the saved nodes.
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    /// We may have several of these import paths associated to one Decl.
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    using SavedImportPathsForOneDecl =
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        llvm::SmallVector<ImportPathTy::VecTy, 32>;
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    using SavedImportPathsTy =
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        llvm::SmallDenseMap<Decl *, SavedImportPathsForOneDecl, 32>;
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    SavedImportPathsTy SavedImportPaths;
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    /// The contexts we're importing to and from.
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    ASTContext &ToContext, &FromContext;
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    /// The file managers we're importing to and from.
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    FileManager &ToFileManager, &FromFileManager;
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    /// Whether to perform a minimal import.
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    bool Minimal;
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    ODRHandlingType ODRHandling;
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    /// Whether the last diagnostic came from the "from" context.
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    bool LastDiagFromFrom = false;
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    /// Mapping from the already-imported types in the "from" context
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    /// to the corresponding types in the "to" context.
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    llvm::DenseMap<const Type *, const Type *> ImportedTypes;
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    /// Mapping from the already-imported declarations in the "from"
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    /// context to the corresponding declarations in the "to" context.
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    llvm::DenseMap<Decl *, Decl *> ImportedDecls;
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    /// Mapping from the already-imported declarations in the "from"
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    /// context to the error status of the import of that declaration.
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    /// This map contains only the declarations that were not correctly
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    /// imported. The same declaration may or may not be included in
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    /// ImportedDecls. This map is updated continuously during imports and never
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    /// cleared (like ImportedDecls).
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    llvm::DenseMap<Decl *, ImportError> ImportDeclErrors;
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    /// Mapping from the already-imported declarations in the "to"
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    /// context to the corresponding declarations in the "from" context.
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    llvm::DenseMap<Decl *, Decl *> ImportedFromDecls;
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    /// Mapping from the already-imported statements in the "from"
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    /// context to the corresponding statements in the "to" context.
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    llvm::DenseMap<Stmt *, Stmt *> ImportedStmts;
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    /// Mapping from the already-imported FileIDs in the "from" source
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    /// manager to the corresponding FileIDs in the "to" source manager.
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    llvm::DenseMap<FileID, FileID> ImportedFileIDs;
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    /// Mapping from the already-imported CXXBasesSpecifier in
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    ///  the "from" source manager to the corresponding CXXBasesSpecifier
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    ///  in the "to" source manager.
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    ImportedCXXBaseSpecifierMap ImportedCXXBaseSpecifiers;
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    /// Declaration (from, to) pairs that are known not to be equivalent
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    /// (which we have already complained about).
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    NonEquivalentDeclSet NonEquivalentDecls;
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    using FoundDeclsTy = SmallVector<NamedDecl *, 2>;
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    FoundDeclsTy findDeclsInToCtx(DeclContext *DC, DeclarationName Name);
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    void AddToLookupTable(Decl *ToD);
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  protected:
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    /// Can be overwritten by subclasses to implement their own import logic.
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    /// The overwritten method should call this method if it didn't import the
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    /// decl on its own.
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    virtual Expected<Decl *> ImportImpl(Decl *From);
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    /// Used only in unittests to verify the behaviour of the error handling.
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3
    virtual bool returnWithErrorInTest() { return false; };
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  public:
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    /// \param ToContext The context we'll be importing into.
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    ///
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    /// \param ToFileManager The file manager we'll be importing into.
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    ///
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    /// \param FromContext The context we'll be importing from.
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    ///
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    /// \param FromFileManager The file manager we'll be importing into.
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    ///
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    /// \param MinimalImport If true, the importer will attempt to import
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    /// as little as it can, e.g., by importing declarations as forward
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    /// declarations that can be completed at a later point.
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    ///
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    /// \param SharedState The importer specific lookup table which may be
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    /// shared amongst several ASTImporter objects.
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    /// If not set then the original C/C++ lookup is used.
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    ASTImporter(ASTContext &ToContext, FileManager &ToFileManager,
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                ASTContext &FromContext, FileManager &FromFileManager,
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                bool MinimalImport,
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                std::shared_ptr<ASTImporterSharedState> SharedState = nullptr);
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    virtual ~ASTImporter();
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    /// Whether the importer will perform a minimal import, creating
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    /// to-be-completed forward declarations when possible.
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2.56M
    bool isMinimalImport() const { return Minimal; }
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24.0k
    void setODRHandling(ODRHandlingType T) { ODRHandling = T; }
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    /// \brief Import the given object, returns the result.
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    ///
331
    /// \param To Import the object into this variable.
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    /// \param From Object to import.
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    /// \return Error information (success or error).
334
    template <typename ImportT>
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6.80M
    LLVM_NODISCARD llvm::Error importInto(ImportT &To, const ImportT &From) {
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6.80M
      auto ToOrErr = Import(From);
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6.80M
      if (ToOrErr)
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6.80M
        To = *ToOrErr;
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6.80M
      return ToOrErr.takeError();
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6.80M
    }
llvm::Error clang::ASTImporter::importInto<clang::DeclarationName>(clang::DeclarationName&, clang::DeclarationName const&)
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Source
335
1.16M
    LLVM_NODISCARD llvm::Error importInto(ImportT &To, const ImportT &From) {
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1.16M
      auto ToOrErr = Import(From);
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1.16M
      if (ToOrErr)
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1.16M
        To = *ToOrErr;
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1.16M
      return ToOrErr.takeError();
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1.16M
    }
llvm::Error clang::ASTImporter::importInto<clang::Type const*>(clang::Type const*&, clang::Type const* const&)
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Count
Source
335
45.5k
    LLVM_NODISCARD llvm::Error importInto(ImportT &To, const ImportT &From) {
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45.5k
      auto ToOrErr = Import(From);
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45.5k
      if (ToOrErr)
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45.5k
        To = *ToOrErr;
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45.5k
      return ToOrErr.takeError();
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45.5k
    }
llvm::Error clang::ASTImporter::importInto<clang::QualType>(clang::QualType&, clang::QualType const&)
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Count
Source
335
875
    LLVM_NODISCARD llvm::Error importInto(ImportT &To, const ImportT &From) {
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875
      auto ToOrErr = Import(From);
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875
      if (ToOrErr)
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875
        To = *ToOrErr;
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875
      return ToOrErr.takeError();
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875
    }
llvm::Error clang::ASTImporter::importInto<clang::SourceRange>(clang::SourceRange&, clang::SourceRange const&)
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Count
Source
335
480k
    LLVM_NODISCARD llvm::Error importInto(ImportT &To, const ImportT &From) {
336
480k
      auto ToOrErr = Import(From);
337
480k
      if (ToOrErr)
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480k
        To = *ToOrErr;
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480k
      return ToOrErr.takeError();
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480k
    }
llvm::Error clang::ASTImporter::importInto<clang::NestedNameSpecifier*>(clang::NestedNameSpecifier*&, clang::NestedNameSpecifier* const&)
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Count
Source
335
1.02M
    LLVM_NODISCARD llvm::Error importInto(ImportT &To, const ImportT &From) {
336
1.02M
      auto ToOrErr = Import(From);
337
1.02M
      if (ToOrErr)
338
1.02M
        To = *ToOrErr;
339
1.02M
      return ToOrErr.takeError();
340
1.02M
    }
llvm::Error clang::ASTImporter::importInto<clang::SourceLocation>(clang::SourceLocation&, clang::SourceLocation const&)
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Count
Source
335
4.08M
    LLVM_NODISCARD llvm::Error importInto(ImportT &To, const ImportT &From) {
336
4.08M
      auto ToOrErr = Import(From);
337
4.08M
      if (ToOrErr)
338
4.08M
        To = *ToOrErr;
339
4.08M
      return ToOrErr.takeError();
340
4.08M
    }
341
342
    /// Import cleanup objects owned by ExprWithCleanup.
343
    llvm::Expected<ExprWithCleanups::CleanupObject>
344
    Import(ExprWithCleanups::CleanupObject From);
345
346
    /// Import the given type from the "from" context into the "to"
347
    /// context.
348
    ///
349
    /// \returns The equivalent type in the "to" context, or the import error.
350
    llvm::Expected<const Type *> Import(const Type *FromT);
351
352
    /// Import the given qualified type from the "from" context into the "to"
353
    /// context. A null type is imported as a null type (no error).
354
    ///
355
    /// \returns The equivalent type in the "to" context, or the import error.
356
    llvm::Expected<QualType> Import(QualType FromT);
357
358
    /// Import the given type source information from the
359
    /// "from" context into the "to" context.
360
    ///
361
    /// \returns The equivalent type source information in the "to"
362
    /// context, or the import error.
363
    llvm::Expected<TypeSourceInfo *> Import(TypeSourceInfo *FromTSI);
364
365
    /// Import the given attribute from the "from" context into the
366
    /// "to" context.
367
    ///
368
    /// \returns The equivalent attribute in the "to" context, or the import
369
    /// error.
370
    llvm::Expected<Attr *> Import(const Attr *FromAttr);
371
372
    /// Import the given declaration from the "from" context into the
373
    /// "to" context.
374
    ///
375
    /// \returns The equivalent declaration in the "to" context, or the import
376
    /// error.
377
    llvm::Expected<Decl *> Import(Decl *FromD);
378
1.23k
    llvm::Expected<const Decl *> Import(const Decl *FromD) {
379
1.23k
      return Import(const_cast<Decl *>(FromD));
380
1.23k
    }
381
382
    /// Return the copy of the given declaration in the "to" context if
383
    /// it has already been imported from the "from" context.  Otherwise return
384
    /// nullptr.
385
    Decl *GetAlreadyImportedOrNull(const Decl *FromD) const;
386
387
    /// Return the translation unit from where the declaration was
388
    /// imported. If it does not exist nullptr is returned.
389
    TranslationUnitDecl *GetFromTU(Decl *ToD);
390
391
    /// Return the declaration in the "from" context from which the declaration
392
    /// in the "to" context was imported. If it was not imported or of the wrong
393
    /// type a null value is returned.
394
    template <typename DeclT>
395
2
    llvm::Optional<DeclT *> getImportedFromDecl(const DeclT *ToD) const {
396
2
      auto FromI = ImportedFromDecls.find(ToD);
397
2
      if (FromI == ImportedFromDecls.end())
398
0
        return {};
399
2
      auto *FromD = dyn_cast<DeclT>(FromI->second);
400
2
      if (!FromD)
401
0
        return {};
402
2
      return FromD;
403
2
    }
404
405
    /// Import the given declaration context from the "from"
406
    /// AST context into the "to" AST context.
407
    ///
408
    /// \returns the equivalent declaration context in the "to"
409
    /// context, or error value.
410
    llvm::Expected<DeclContext *> ImportContext(DeclContext *FromDC);
411
412
    /// Import the given expression from the "from" context into the
413
    /// "to" context.
414
    ///
415
    /// \returns The equivalent expression in the "to" context, or the import
416
    /// error.
417
    llvm::Expected<Expr *> Import(Expr *FromE);
418
419
    /// Import the given statement from the "from" context into the
420
    /// "to" context.
421
    ///
422
    /// \returns The equivalent statement in the "to" context, or the import
423
    /// error.
424
    llvm::Expected<Stmt *> Import(Stmt *FromS);
425
426
    /// Import the given nested-name-specifier from the "from"
427
    /// context into the "to" context.
428
    ///
429
    /// \returns The equivalent nested-name-specifier in the "to"
430
    /// context, or the import error.
431
    llvm::Expected<NestedNameSpecifier *> Import(NestedNameSpecifier *FromNNS);
432
433
    /// Import the given nested-name-specifier-loc from the "from"
434
    /// context into the "to" context.
435
    ///
436
    /// \returns The equivalent nested-name-specifier-loc in the "to"
437
    /// context, or the import error.
438
    llvm::Expected<NestedNameSpecifierLoc>
439
    Import(NestedNameSpecifierLoc FromNNS);
440
441
    /// Import the given template name from the "from" context into the
442
    /// "to" context, or the import error.
443
    llvm::Expected<TemplateName> Import(TemplateName From);
444
445
    /// Import the given source location from the "from" context into
446
    /// the "to" context.
447
    ///
448
    /// \returns The equivalent source location in the "to" context, or the
449
    /// import error.
450
    llvm::Expected<SourceLocation> Import(SourceLocation FromLoc);
451
452
    /// Import the given source range from the "from" context into
453
    /// the "to" context.
454
    ///
455
    /// \returns The equivalent source range in the "to" context, or the import
456
    /// error.
457
    llvm::Expected<SourceRange> Import(SourceRange FromRange);
458
459
    /// Import the given declaration name from the "from"
460
    /// context into the "to" context.
461
    ///
462
    /// \returns The equivalent declaration name in the "to" context, or the
463
    /// import error.
464
    llvm::Expected<DeclarationName> Import(DeclarationName FromName);
465
466
    /// Import the given identifier from the "from" context
467
    /// into the "to" context.
468
    ///
469
    /// \returns The equivalent identifier in the "to" context. Note: It
470
    /// returns nullptr only if the FromId was nullptr.
471
    IdentifierInfo *Import(const IdentifierInfo *FromId);
472
473
    /// Import the given Objective-C selector from the "from"
474
    /// context into the "to" context.
475
    ///
476
    /// \returns The equivalent selector in the "to" context, or the import
477
    /// error.
478
    llvm::Expected<Selector> Import(Selector FromSel);
479
480
    /// Import the given file ID from the "from" context into the
481
    /// "to" context.
482
    ///
483
    /// \returns The equivalent file ID in the source manager of the "to"
484
    /// context, or the import error.
485
    llvm::Expected<FileID> Import(FileID, bool IsBuiltin = false);
486
487
    /// Import the given C++ constructor initializer from the "from"
488
    /// context into the "to" context.
489
    ///
490
    /// \returns The equivalent initializer in the "to" context, or the import
491
    /// error.
492
    llvm::Expected<CXXCtorInitializer *> Import(CXXCtorInitializer *FromInit);
493
494
    /// Import the given CXXBaseSpecifier from the "from" context into
495
    /// the "to" context.
496
    ///
497
    /// \returns The equivalent CXXBaseSpecifier in the source manager of the
498
    /// "to" context, or the import error.
499
    llvm::Expected<CXXBaseSpecifier *> Import(const CXXBaseSpecifier *FromSpec);
500
501
    /// Import the given APValue from the "from" context into
502
    /// the "to" context.
503
    ///
504
    /// \return the equivalent APValue in the "to" context or the import
505
    /// error.
506
    llvm::Expected<APValue> Import(const APValue &FromValue);
507
508
    /// Import the definition of the given declaration, including all of
509
    /// the declarations it contains.
510
    LLVM_NODISCARD llvm::Error ImportDefinition(Decl *From);
511
512
    /// Cope with a name conflict when importing a declaration into the
513
    /// given context.
514
    ///
515
    /// This routine is invoked whenever there is a name conflict while
516
    /// importing a declaration. The returned name will become the name of the
517
    /// imported declaration. By default, the returned name is the same as the
518
    /// original name, leaving the conflict unresolve such that name lookup
519
    /// for this name is likely to find an ambiguity later.
520
    ///
521
    /// Subclasses may override this routine to resolve the conflict, e.g., by
522
    /// renaming the declaration being imported.
523
    ///
524
    /// \param Name the name of the declaration being imported, which conflicts
525
    /// with other declarations.
526
    ///
527
    /// \param DC the declaration context (in the "to" AST context) in which
528
    /// the name is being imported.
529
    ///
530
    /// \param IDNS the identifier namespace in which the name will be found.
531
    ///
532
    /// \param Decls the set of declarations with the same name as the
533
    /// declaration being imported.
534
    ///
535
    /// \param NumDecls the number of conflicting declarations in \p Decls.
536
    ///
537
    /// \returns the name that the newly-imported declaration should have. Or
538
    /// an error if we can't handle the name conflict.
539
    virtual Expected<DeclarationName>
540
    HandleNameConflict(DeclarationName Name, DeclContext *DC, unsigned IDNS,
541
                       NamedDecl **Decls, unsigned NumDecls);
542
543
    /// Retrieve the context that AST nodes are being imported into.
544
16.0M
    ASTContext &getToContext() const { return ToContext; }
545
546
    /// Retrieve the context that AST nodes are being imported from.
547
4.72M
    ASTContext &getFromContext() const { return FromContext; }
548
549
    /// Retrieve the file manager that AST nodes are being imported into.
550
0
    FileManager &getToFileManager() const { return ToFileManager; }
551
552
    /// Retrieve the file manager that AST nodes are being imported from.
553
0
    FileManager &getFromFileManager() const { return FromFileManager; }
554
555
    /// Report a diagnostic in the "to" context.
556
    DiagnosticBuilder ToDiag(SourceLocation Loc, unsigned DiagID);
557
558
    /// Report a diagnostic in the "from" context.
559
    DiagnosticBuilder FromDiag(SourceLocation Loc, unsigned DiagID);
560
561
    /// Return the set of declarations that we know are not equivalent.
562
1.67M
    NonEquivalentDeclSet &getNonEquivalentDecls() { return NonEquivalentDecls; }
563
564
    /// Called for ObjCInterfaceDecl, ObjCProtocolDecl, and TagDecl.
565
    /// Mark the Decl as complete, filling it in as much as possible.
566
    ///
567
    /// \param D A declaration in the "to" context.
568
    virtual void CompleteDecl(Decl* D);
569
570
    /// Subclasses can override this function to observe all of the \c From ->
571
    /// \c To declaration mappings as they are imported.
572
76.2k
    virtual void Imported(Decl *From, Decl *To) {}
573
574
    void RegisterImportedDecl(Decl *FromD, Decl *ToD);
575
576
    /// Store and assign the imported declaration to its counterpart.
577
    /// It may happen that several decls from the 'from' context are mapped to
578
    /// the same decl in the 'to' context.
579
    Decl *MapImported(Decl *From, Decl *To);
580
581
    /// Called by StructuralEquivalenceContext.  If a RecordDecl is
582
    /// being compared to another RecordDecl as part of import, completing the
583
    /// other RecordDecl may trigger importation of the first RecordDecl. This
584
    /// happens especially for anonymous structs.  If the original of the second
585
    /// RecordDecl can be found, we can complete it without the need for
586
    /// importation, eliminating this loop.
587
748
    virtual Decl *GetOriginalDecl(Decl *To) { return nullptr; }
588
589
    /// Return if import of the given declaration has failed and if yes
590
    /// the kind of the problem. This gives the first error encountered with
591
    /// the node.
592
    llvm::Optional<ImportError> getImportDeclErrorIfAny(Decl *FromD) const;
593
594
    /// Mark (newly) imported declaration with error.
595
    void setImportDeclError(Decl *From, ImportError Error);
596
597
    /// Determine whether the given types are structurally
598
    /// equivalent.
599
    bool IsStructurallyEquivalent(QualType From, QualType To,
600
                                  bool Complain = true);
601
602
    /// Determine the index of a field in its parent record.
603
    /// F should be a field (or indirect field) declaration.
604
    /// \returns The index of the field in its parent context (starting from 0).
605
    /// On error `None` is returned (parent context is non-record).
606
    static llvm::Optional<unsigned> getFieldIndex(Decl *F);
607
  };
608
609
} // namespace clang
610
611
#endif // LLVM_CLANG_AST_ASTIMPORTER_H