ExternalSemaSource.h

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//===--- ExternalSemaSource.h - External Sema Interface ---------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
//  This file defines the ExternalSemaSource interface.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_CLANG_SEMA_EXTERNALSEMASOURCE_H
#define LLVM_CLANG_SEMA_EXTERNALSEMASOURCE_H
 
#include "clang/AST/ExternalASTSource.h"
#include "clang/AST/Type.h"
#include "clang/Sema/TypoCorrection.h"
#include "clang/Sema/Weak.h"
#include "llvm/ADT/MapVector.h"
#include <utility>
 
namespace llvm {
template <class T, unsigned n> class SmallSetVector;
}
 
namespace clang {
 
class CXXConstructorDecl;
class CXXRecordDecl;
class DeclaratorDecl;
class LookupResult;
class Scope;
class Sema;
class TypedefNameDecl;
class ValueDecl;
class VarDecl;
struct LateParsedTemplate;
 
/// A simple structure that captures a vtable use for the purposes of
/// the \c ExternalSemaSource.
struct ExternalVTableUse {
  CXXRecordDecl *Record;
  SourceLocation Location;
  bool DefinitionRequired;
};
 
/// An abstract interface that should be implemented by
/// external AST sources that also provide information for semantic
/// analysis.
class ExternalSemaSource : public ExternalASTSource {
  /// LLVM-style RTTI.
  static char ID;
 
public:
  ExternalSemaSource() = default;
 
  ~ExternalSemaSource() override;
 
  /// Initialize the semantic source with the Sema instance
  /// being used to perform semantic analysis on the abstract syntax
  /// tree.
  virtual void InitializeSema(Sema &S) {}
 
  /// Inform the semantic consumer that Sema is no longer available.
  virtual void ForgetSema() {}
 
  /// Load the contents of the global method pool for a given
  /// selector.
  virtual void ReadMethodPool(Selector Sel);
 
  /// Load the contents of the global method pool for a given
  /// selector if necessary.
  virtual void updateOutOfDateSelector(Selector Sel);
 
  /// Load the set of namespaces that are known to the external source,
  /// which will be used during typo correction.
  virtual void ReadKnownNamespaces(
                           SmallVectorImpl<NamespaceDecl *> &Namespaces);
 
  /// Load the set of used but not defined functions or variables with
  /// internal linkage, or used but not defined internal functions.
  virtual void
  ReadUndefinedButUsed(llvm::MapVector<NamedDecl *, SourceLocation> &Undefined);
 
  virtual void ReadMismatchingDeleteExpressions(llvm::MapVector<
      FieldDecl *, llvm::SmallVector<std::pair<SourceLocation, bool>, 4>> &);
 
  /// Do last resort, unqualified lookup on a LookupResult that
  /// Sema cannot find.
  ///
  /// \param R a LookupResult that is being recovered.
  ///
  /// \param S the Scope of the identifier occurrence.
  ///
  /// \return true to tell Sema to recover using the LookupResult.
  virtual bool LookupUnqualified(LookupResult &R, Scope *S) { return false; }
 
  /// Read the set of tentative definitions known to the external Sema
  /// source.
  ///
  /// The external source should append its own tentative definitions to the
  /// given vector of tentative definitions. Note that this routine may be
  /// invoked multiple times; the external source should take care not to
  /// introduce the same declarations repeatedly.
  virtual void ReadTentativeDefinitions(
                                  SmallVectorImpl<VarDecl *> &TentativeDefs) {}
 
  /// Read the set of unused file-scope declarations known to the
  /// external Sema source.
  ///
  /// The external source should append its own unused, filed-scope to the
  /// given vector of declarations. Note that this routine may be
  /// invoked multiple times; the external source should take care not to
  /// introduce the same declarations repeatedly.
  virtual void ReadUnusedFileScopedDecls(
                 SmallVectorImpl<const DeclaratorDecl *> &Decls) {}
 
  /// Read the set of delegating constructors known to the
  /// external Sema source.
  ///
  /// The external source should append its own delegating constructors to the
  /// given vector of declarations. Note that this routine may be
  /// invoked multiple times; the external source should take care not to
  /// introduce the same declarations repeatedly.
  virtual void ReadDelegatingConstructors(
                 SmallVectorImpl<CXXConstructorDecl *> &Decls) {}
 
  /// Read the set of ext_vector type declarations known to the
  /// external Sema source.
  ///
  /// The external source should append its own ext_vector type declarations to
  /// the given vector of declarations. Note that this routine may be
  /// invoked multiple times; the external source should take care not to
  /// introduce the same declarations repeatedly.
  virtual void ReadExtVectorDecls(SmallVectorImpl<TypedefNameDecl *> &Decls) {}
 
  /// Read the set of potentially unused typedefs known to the source.
  ///
  /// The external source should append its own potentially unused local
  /// typedefs to the given vector of declarations. Note that this routine may
  /// be invoked multiple times; the external source should take care not to
  /// introduce the same declarations repeatedly.
  virtual void ReadUnusedLocalTypedefNameCandidates(
      llvm::SmallPtrSetImpl<const TypedefNameDecl *> &Decls) {}
 
  /// Read the set of referenced selectors known to the
  /// external Sema source.
  ///
  /// The external source should append its own referenced selectors to the
  /// given vector of selectors. Note that this routine
  /// may be invoked multiple times; the external source should take care not
  /// to introduce the same selectors repeatedly.
  virtual void ReadReferencedSelectors(
                 SmallVectorImpl<std::pair<Selector, SourceLocation> > &Sels) {}
 
  /// Read the set of weak, undeclared identifiers known to the
  /// external Sema source.
  ///
  /// The external source should append its own weak, undeclared identifiers to
  /// the given vector. Note that this routine may be invoked multiple times;
  /// the external source should take care not to introduce the same identifiers
  /// repeatedly.
  virtual void ReadWeakUndeclaredIdentifiers(
                 SmallVectorImpl<std::pair<IdentifierInfo *, WeakInfo> > &WI) {}
 
  /// Read the set of #pragma redefine_extname'd, undeclared identifiers known
  /// to the external Sema source.
  ///
  /// The external source should append its own #pragma redefine_extname'd,
  /// undeclared identifiers to the given vector. Note that this routine may be
  /// invoked multiple times; the external source should take care not to
  /// introduce the same identifiers repeatedly.
  virtual void ReadExtnameUndeclaredIdentifiers(
      SmallVectorImpl<std::pair<IdentifierInfo *, AsmLabelAttr *>> &EI) {}
 
  /// Read the set of used vtables known to the external Sema source.
  ///
  /// The external source should append its own used vtables to the given
  /// vector. Note that this routine may be invoked multiple times; the external
  /// source should take care not to introduce the same vtables repeatedly.
  virtual void ReadUsedVTables(SmallVectorImpl<ExternalVTableUse> &VTables) {}
 
  /// Read the set of pending instantiations known to the external
  /// Sema source.
  ///
  /// The external source should append its own pending instantiations to the
  /// given vector. Note that this routine may be invoked multiple times; the
  /// external source should take care not to introduce the same instantiations
  /// repeatedly.
  virtual void ReadPendingInstantiations(
                 SmallVectorImpl<std::pair<ValueDecl *,
                                           SourceLocation> > &Pending) {}
 
  /// Read the set of late parsed template functions for this source.
  ///
  /// The external source should insert its own late parsed template functions
  /// into the map. Note that this routine may be invoked multiple times; the
  /// external source should take care not to introduce the same map entries
  /// repeatedly.
  virtual void ReadLateParsedTemplates(
      llvm::MapVector<const FunctionDecl *, std::unique_ptr<LateParsedTemplate>>
          &LPTMap) {}
 
  /// Read the set of decls to be checked for deferred diags.
  ///
  /// The external source should append its own potentially emitted function
  /// and variable decls which may cause deferred diags. Note that this routine
  /// may be invoked multiple times; the external source should take care not to
  /// introduce the same declarations repeatedly.
  virtual void
  ReadDeclsToCheckForDeferredDiags(llvm::SmallSetVector<Decl *, 4> &Decls) {}
 
  /// \copydoc Sema::CorrectTypo
  /// \note LookupKind must correspond to a valid Sema::LookupNameKind
  ///
  /// ExternalSemaSource::CorrectTypo is always given the first chance to
  /// correct a typo (really, to offer suggestions to repair a failed lookup).
  /// It will even be called when SpellChecking is turned off or after a
  /// fatal error has already been detected.
  virtual TypoCorrection CorrectTypo(const DeclarationNameInfo &Typo,
                                     int LookupKind, Scope *S, CXXScopeSpec *SS,
                                     CorrectionCandidateCallback &CCC,
                                     DeclContext *MemberContext,
                                     bool EnteringContext,
                                     const ObjCObjectPointerType *OPT) {
    return TypoCorrection();
  }
 
  /// Produces a diagnostic note if the external source contains a
  /// complete definition for \p T.
  ///
  /// \param Loc the location at which a complete type was required but not
  /// provided
  ///
  /// \param T the \c QualType that should have been complete at \p Loc
  ///
  /// \return true if a diagnostic was produced, false otherwise.
  virtual bool MaybeDiagnoseMissingCompleteType(SourceLocation Loc,
                                                QualType T) {
    return false;
  }
 
  /// LLVM-style RTTI.
  /// \{
  bool isA(const void *ClassID) const override {
    return ClassID == &ID || ExternalASTSource::isA(ClassID);
  }
  static bool classof(const ExternalASTSource *S) { return S->isA(&ID); }
  /// \}
};
 
/// Represents a lazily-loaded vector of data.
///
/// The lazily-loaded vector of data contains data that is partially loaded
/// from an external source and partially added by local translation. The
/// items loaded from the external source are loaded lazily, when needed for
/// iteration over the complete vector.
template <typename T, void (ExternalSemaSource::*Loader)(SmallVectorImpl<T> &),
          unsigned LoadedStorage = 2, unsigned LocalStorage = 4>
class LazyVector {
  SmallVector<T, LoadedStorage> Loaded;
  SmallVector<T, LocalStorage> Local;
 
public:
  /// Iteration over the elements in the vector.
  ///
  /// In a complete iteration, the iterator walks the range [-M, N),
  /// where negative values are used to indicate elements
  /// loaded from the external source while non-negative values are used to
  /// indicate elements added via \c push_back().
  /// However, to provide iteration in source order (for, e.g., chained
  /// precompiled headers), dereferencing the iterator flips the negative
  /// values (corresponding to loaded entities), so that position -M
  /// corresponds to element 0 in the loaded entities vector, position -M+1
  /// corresponds to element 1 in the loaded entities vector, etc. This
  /// gives us a reasonably efficient, source-order walk.
  ///
  /// We define this as a wrapping iterator around an int. The
  /// iterator_adaptor_base class forwards the iterator methods to basic integer
  /// arithmetic.
  class iterator
      : public llvm::iterator_adaptor_base<
            iterator, int, std::random_access_iterator_tag, T, int, T *, T &> {
    friend class LazyVector;
 
    LazyVector *Self;
 
    iterator(LazyVector *Self, int Position)
        : iterator::iterator_adaptor_base(Position), Self(Self) {}
 
    bool isLoaded() const { return this->I < 0; }
 
  public:
    iterator() : iterator(nullptr, 0) {}
 
    typename iterator::reference operator*() const {
      if (isLoaded())
        return Self->Loaded.end()[this->I];
      return Self->Local.begin()[this->I];
    }
  };
 
  iterator begin(ExternalSemaSource *source, bool LocalOnly = false) {
    if (LocalOnly)
      return iterator(this, 0);
 
    if (source)
      (source->*Loader)(Loaded);
    return iterator(this, -(int)Loaded.size());
  }
 
  iterator end() { return iterator(this, Local.size()); }
 
  void push_back(const T &LocalValue) { Local.push_back(LocalValue); }
 
  void erase(iterator From, iterator To) {
    if (From.isLoaded() && To.isLoaded()) {
      Loaded.erase(&*From, &*To);
      return;
    }
 
    if (From.isLoaded()) {
      Loaded.erase(&*From, Loaded.end());
      From = begin(nullptr, true);
    }
 
    Local.erase(&*From, &*To);
  }
};
 
} // end namespace clang
 
#endif