C++ NamedDecl::getAccess方法代码示例

/// Determines whether the accessed entity is accessible.  Public members
/// have been weeded out by this point.
static AccessResult IsAccessible(Sema &S,
                                 const EffectiveContext &EC,
                                 AccessTarget &Entity) {
  // Determine the actual naming class.
  CXXRecordDecl *NamingClass = Entity.getNamingClass();
  while (NamingClass->isAnonymousStructOrUnion())
    NamingClass = cast<CXXRecordDecl>(NamingClass->getParent());
  NamingClass = NamingClass->getCanonicalDecl();

  AccessSpecifier UnprivilegedAccess = Entity.getAccess();
  assert(UnprivilegedAccess != AS_public && "public access not weeded out");

  // Before we try to recalculate access paths, try to white-list
  // accesses which just trade in on the final step, i.e. accesses
  // which don't require [M4] or [B4]. These are by far the most
  // common forms of privileged access.
  if (UnprivilegedAccess != AS_none) {
    switch (HasAccess(S, EC, NamingClass, UnprivilegedAccess, Entity)) {
    case AR_dependent:
      // This is actually an interesting policy decision.  We don't
      // *have* to delay immediately here: we can do the full access
      // calculation in the hope that friendship on some intermediate
      // class will make the declaration accessible non-dependently.
      // But that's not cheap, and odds are very good (note: assertion
      // made without data) that the friend declaration will determine
      // access.
      return AR_dependent;

    case AR_accessible: return AR_accessible;
    case AR_inaccessible: break;
    }
  }

  AccessTarget::SavedInstanceContext _ = Entity.saveInstanceContext();

  // We lower member accesses to base accesses by pretending that the
  // member is a base class of its declaring class.
  AccessSpecifier FinalAccess;

  if (Entity.isMemberAccess()) {
    // Determine if the declaration is accessible from EC when named
    // in its declaring class.
    NamedDecl *Target = Entity.getTargetDecl();
    const CXXRecordDecl *DeclaringClass = Entity.getDeclaringClass();

    FinalAccess = Target->getAccess();
    switch (HasAccess(S, EC, DeclaringClass, FinalAccess, Entity)) {
    case AR_accessible:
      FinalAccess = AS_public;
      break;
    case AR_inaccessible: break;
    case AR_dependent: return AR_dependent; // see above
    }

    if (DeclaringClass == NamingClass)
      return (FinalAccess == AS_public ? AR_accessible : AR_inaccessible);

    Entity.suppressInstanceContext();
  } else {
    FinalAccess = AS_public;
  }

  assert(Entity.getDeclaringClass() != NamingClass);

  // Append the declaration's access if applicable.
  CXXBasePaths Paths;
  CXXBasePath *Path = FindBestPath(S, EC, Entity, FinalAccess, Paths);
  if (!Path)
    return AR_dependent;

  assert(Path->Access <= UnprivilegedAccess &&
         "access along best path worse than direct?");
  if (Path->Access == AS_public)
    return AR_accessible;
  return AR_inaccessible;
}

/// Diagnose the path which caused the given declaration or base class
/// to become inaccessible.
static void DiagnoseAccessPath(Sema &S,
                               const EffectiveContext &EC,
                               AccessTarget &Entity) {
  AccessSpecifier Access = Entity.getAccess();
  const CXXRecordDecl *NamingClass = Entity.getNamingClass();
  NamingClass = NamingClass->getCanonicalDecl();

  NamedDecl *D = (Entity.isMemberAccess() ? Entity.getTargetDecl() : 0);
  const CXXRecordDecl *DeclaringClass = Entity.getDeclaringClass();

  // Easy case: the decl's natural access determined its path access.
  // We have to check against AS_private here in case Access is AS_none,
  // indicating a non-public member of a private base class.
  if (D && (Access == D->getAccess() || D->getAccess() == AS_private)) {
    switch (HasAccess(S, EC, DeclaringClass, D->getAccess(), Entity)) {
    case AR_inaccessible: {
      S.Diag(D->getLocation(), diag::note_access_natural)
        << (unsigned) (Access == AS_protected)
        << /*FIXME: not implicitly*/ 0;
      return;
    }

    case AR_accessible: break;

    case AR_dependent:
      llvm_unreachable("can't diagnose dependent access failures");
      return;
    }
  }

  CXXBasePaths Paths;
  CXXBasePath &Path = *FindBestPath(S, EC, Entity, AS_public, Paths);

  CXXBasePath::iterator I = Path.end(), E = Path.begin();
  while (I != E) {
    --I;

    const CXXBaseSpecifier *BS = I->Base;
    AccessSpecifier BaseAccess = BS->getAccessSpecifier();

    // If this is public inheritance, or the derived class is a friend,
    // skip this step.
    if (BaseAccess == AS_public)
      continue;

    switch (GetFriendKind(S, EC, I->Class)) {
    case AR_accessible: continue;
    case AR_inaccessible: break;
    case AR_dependent:
      llvm_unreachable("can't diagnose dependent access failures");
    }

    // Check whether this base specifier is the tighest point
    // constraining access.  We have to check against AS_private for
    // the same reasons as above.
    if (BaseAccess == AS_private || BaseAccess >= Access) {

      // We're constrained by inheritance, but we want to say
      // "declared private here" if we're diagnosing a hierarchy
      // conversion and this is the final step.
      unsigned diagnostic;
      if (D) diagnostic = diag::note_access_constrained_by_path;
      else if (I + 1 == Path.end()) diagnostic = diag::note_access_natural;
      else diagnostic = diag::note_access_constrained_by_path;

      S.Diag(BS->getSourceRange().getBegin(), diagnostic)
        << BS->getSourceRange()
        << (BaseAccess == AS_protected)
        << (BS->getAccessSpecifierAsWritten() == AS_none);
      return;
    }
  }

  llvm_unreachable("access not apparently constrained by path");
}