SemaAccess.cpp revision 9c3087b0b0bea2fd782205c1274ebfc4290265e0 
1//===---- SemaAccess.cpp - C++ Access Control -------------------*- C++ -*-===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This file provides Sema routines for C++ access control semantics.
11//
12//===----------------------------------------------------------------------===//
13
14#include "clang/Sema/SemaInternal.h"
15#include "clang/Sema/DelayedDiagnostic.h"
16#include "clang/Sema/Initialization.h"
17#include "clang/Sema/Lookup.h"
18#include "clang/AST/ASTContext.h"
19#include "clang/AST/CXXInheritance.h"
20#include "clang/AST/DeclCXX.h"
21#include "clang/AST/DeclFriend.h"
22#include "clang/AST/DependentDiagnostic.h"
23#include "clang/AST/ExprCXX.h"
24
25using namespace clang;
26using namespace sema;
27
28/// A copy of Sema's enum without AR_delayed.
29enum AccessResult {
30  AR_accessible,
31  AR_inaccessible,
32  AR_dependent
33};
34
35/// SetMemberAccessSpecifier - Set the access specifier of a member.
36/// Returns true on error (when the previous member decl access specifier
37/// is different from the new member decl access specifier).
38bool Sema::SetMemberAccessSpecifier(NamedDecl *MemberDecl,
39                                    NamedDecl *PrevMemberDecl,
40                                    AccessSpecifier LexicalAS) {
41  if (!PrevMemberDecl) {
42    // Use the lexical access specifier.
43    MemberDecl->setAccess(LexicalAS);
44    return false;
45  }
46
47  // C++ [class.access.spec]p3: When a member is redeclared its access
48  // specifier must be same as its initial declaration.
49  if (LexicalAS != AS_none && LexicalAS != PrevMemberDecl->getAccess()) {
50    Diag(MemberDecl->getLocation(),
51         diag::err_class_redeclared_with_different_access)
52      << MemberDecl << LexicalAS;
53    Diag(PrevMemberDecl->getLocation(), diag::note_previous_access_declaration)
54      << PrevMemberDecl << PrevMemberDecl->getAccess();
55
56    MemberDecl->setAccess(LexicalAS);
57    return true;
58  }
59
60  MemberDecl->setAccess(PrevMemberDecl->getAccess());
61  return false;
62}
63
64static CXXRecordDecl *FindDeclaringClass(NamedDecl *D) {
65  DeclContext *DC = D->getDeclContext();
66
67  // This can only happen at top: enum decls only "publish" their
68  // immediate members.
69  if (isa<EnumDecl>(DC))
70    DC = cast<EnumDecl>(DC)->getDeclContext();
71
72  CXXRecordDecl *DeclaringClass = cast<CXXRecordDecl>(DC);
73  while (DeclaringClass->isAnonymousStructOrUnion())
74    DeclaringClass = cast<CXXRecordDecl>(DeclaringClass->getDeclContext());
75  return DeclaringClass;
76}
77
78namespace {
79struct EffectiveContext {
80  EffectiveContext() : Inner(0), Dependent(false) {}
81
82  explicit EffectiveContext(DeclContext *DC)
83    : Inner(DC),
84      Dependent(DC->isDependentContext()) {
85
86    // C++ [class.access.nest]p1:
87    //   A nested class is a member and as such has the same access
88    //   rights as any other member.
89    // C++ [class.access]p2:
90    //   A member of a class can also access all the names to which
91    //   the class has access.  A local class of a member function
92    //   may access the same names that the member function itself
93    //   may access.
94    // This almost implies that the privileges of nesting are transitive.
95    // Technically it says nothing about the local classes of non-member
96    // functions (which can gain privileges through friendship), but we
97    // take that as an oversight.
98    while (true) {
99      if (isa<CXXRecordDecl>(DC)) {
100        CXXRecordDecl *Record = cast<CXXRecordDecl>(DC)->getCanonicalDecl();
101        Records.push_back(Record);
102        DC = Record->getDeclContext();
103      } else if (isa<FunctionDecl>(DC)) {
104        FunctionDecl *Function = cast<FunctionDecl>(DC)->getCanonicalDecl();
105        Functions.push_back(Function);
106        DC = Function->getDeclContext();
107      } else if (DC->isFileContext()) {
108        break;
109      } else {
110        DC = DC->getParent();
111      }
112    }
113  }
114
115  bool isDependent() const { return Dependent; }
116
117  bool includesClass(const CXXRecordDecl *R) const {
118    R = R->getCanonicalDecl();
119    return std::find(Records.begin(), Records.end(), R)
120             != Records.end();
121  }
122
123  /// Retrieves the innermost "useful" context.  Can be null if we're
124  /// doing access-control without privileges.
125  DeclContext *getInnerContext() const {
126    return Inner;
127  }
128
129  typedef llvm::SmallVectorImpl<CXXRecordDecl*>::const_iterator record_iterator;
130
131  DeclContext *Inner;
132  llvm::SmallVector<FunctionDecl*, 4> Functions;
133  llvm::SmallVector<CXXRecordDecl*, 4> Records;
134  bool Dependent;
135};
136
137/// Like sema:;AccessedEntity, but kindly lets us scribble all over
138/// it.
139struct AccessTarget : public AccessedEntity {
140  AccessTarget(const AccessedEntity &Entity)
141    : AccessedEntity(Entity) {
142    initialize();
143  }
144
145  AccessTarget(ASTContext &Context,
146               MemberNonce _,
147               CXXRecordDecl *NamingClass,
148               DeclAccessPair FoundDecl,
149               QualType BaseObjectType)
150    : AccessedEntity(Context, Member, NamingClass, FoundDecl, BaseObjectType) {
151    initialize();
152  }
153
154  AccessTarget(ASTContext &Context,
155               BaseNonce _,
156               CXXRecordDecl *BaseClass,
157               CXXRecordDecl *DerivedClass,
158               AccessSpecifier Access)
159    : AccessedEntity(Context, Base, BaseClass, DerivedClass, Access) {
160    initialize();
161  }
162
163  bool hasInstanceContext() const {
164    return HasInstanceContext;
165  }
166
167  class SavedInstanceContext {
168  public:
169    ~SavedInstanceContext() {
170      Target.HasInstanceContext = Has;
171    }
172
173  private:
174    friend struct AccessTarget;
175    explicit SavedInstanceContext(AccessTarget &Target)
176      : Target(Target), Has(Target.HasInstanceContext) {}
177    AccessTarget &Target;
178    bool Has;
179  };
180
181  SavedInstanceContext saveInstanceContext() {
182    return SavedInstanceContext(*this);
183  }
184
185  void suppressInstanceContext() {
186    HasInstanceContext = false;
187  }
188
189  const CXXRecordDecl *resolveInstanceContext(Sema &S) const {
190    assert(HasInstanceContext);
191    if (CalculatedInstanceContext)
192      return InstanceContext;
193
194    CalculatedInstanceContext = true;
195    DeclContext *IC = S.computeDeclContext(getBaseObjectType());
196    InstanceContext = (IC ? cast<CXXRecordDecl>(IC)->getCanonicalDecl() : 0);
197    return InstanceContext;
198  }
199
200  const CXXRecordDecl *getDeclaringClass() const {
201    return DeclaringClass;
202  }
203
204private:
205  void initialize() {
206    HasInstanceContext = (isMemberAccess() &&
207                          !getBaseObjectType().isNull() &&
208                          getTargetDecl()->isCXXInstanceMember());
209    CalculatedInstanceContext = false;
210    InstanceContext = 0;
211
212    if (isMemberAccess())
213      DeclaringClass = FindDeclaringClass(getTargetDecl());
214    else
215      DeclaringClass = getBaseClass();
216    DeclaringClass = DeclaringClass->getCanonicalDecl();
217  }
218
219  bool HasInstanceContext : 1;
220  mutable bool CalculatedInstanceContext : 1;
221  mutable const CXXRecordDecl *InstanceContext;
222  const CXXRecordDecl *DeclaringClass;
223};
224
225}
226
227/// Checks whether one class might instantiate to the other.
228static bool MightInstantiateTo(const CXXRecordDecl *From,
229                               const CXXRecordDecl *To) {
230  // Declaration names are always preserved by instantiation.
231  if (From->getDeclName() != To->getDeclName())
232    return false;
233
234  const DeclContext *FromDC = From->getDeclContext()->getPrimaryContext();
235  const DeclContext *ToDC = To->getDeclContext()->getPrimaryContext();
236  if (FromDC == ToDC) return true;
237  if (FromDC->isFileContext() || ToDC->isFileContext()) return false;
238
239  // Be conservative.
240  return true;
241}
242
243/// Checks whether one class is derived from another, inclusively.
244/// Properly indicates when it couldn't be determined due to
245/// dependence.
246///
247/// This should probably be donated to AST or at least Sema.
248static AccessResult IsDerivedFromInclusive(const CXXRecordDecl *Derived,
249                                           const CXXRecordDecl *Target) {
250  assert(Derived->getCanonicalDecl() == Derived);
251  assert(Target->getCanonicalDecl() == Target);
252
253  if (Derived == Target) return AR_accessible;
254
255  bool CheckDependent = Derived->isDependentContext();
256  if (CheckDependent && MightInstantiateTo(Derived, Target))
257    return AR_dependent;
258
259  AccessResult OnFailure = AR_inaccessible;
260  llvm::SmallVector<const CXXRecordDecl*, 8> Queue; // actually a stack
261
262  while (true) {
263    for (CXXRecordDecl::base_class_const_iterator
264           I = Derived->bases_begin(), E = Derived->bases_end(); I != E; ++I) {
265
266      const CXXRecordDecl *RD;
267
268      QualType T = I->getType();
269      if (const RecordType *RT = T->getAs<RecordType>()) {
270        RD = cast<CXXRecordDecl>(RT->getDecl());
271      } else if (const InjectedClassNameType *IT
272                   = T->getAs<InjectedClassNameType>()) {
273        RD = IT->getDecl();
274      } else {
275        assert(T->isDependentType() && "non-dependent base wasn't a record?");
276        OnFailure = AR_dependent;
277        continue;
278      }
279
280      RD = RD->getCanonicalDecl();
281      if (RD == Target) return AR_accessible;
282      if (CheckDependent && MightInstantiateTo(RD, Target))
283        OnFailure = AR_dependent;
284
285      Queue.push_back(RD);
286    }
287
288    if (Queue.empty()) break;
289
290    Derived = Queue.back();
291    Queue.pop_back();
292  }
293
294  return OnFailure;
295}
296
297
298static bool MightInstantiateTo(Sema &S, DeclContext *Context,
299                               DeclContext *Friend) {
300  if (Friend == Context)
301    return true;
302
303  assert(!Friend->isDependentContext() &&
304         "can't handle friends with dependent contexts here");
305
306  if (!Context->isDependentContext())
307    return false;
308
309  if (Friend->isFileContext())
310    return false;
311
312  // TODO: this is very conservative
313  return true;
314}
315
316// Asks whether the type in 'context' can ever instantiate to the type
317// in 'friend'.
318static bool MightInstantiateTo(Sema &S, CanQualType Context, CanQualType Friend) {
319  if (Friend == Context)
320    return true;
321
322  if (!Friend->isDependentType() && !Context->isDependentType())
323    return false;
324
325  // TODO: this is very conservative.
326  return true;
327}
328
329static bool MightInstantiateTo(Sema &S,
330                               FunctionDecl *Context,
331                               FunctionDecl *Friend) {
332  if (Context->getDeclName() != Friend->getDeclName())
333    return false;
334
335  if (!MightInstantiateTo(S,
336                          Context->getDeclContext(),
337                          Friend->getDeclContext()))
338    return false;
339
340  CanQual<FunctionProtoType> FriendTy
341    = S.Context.getCanonicalType(Friend->getType())
342         ->getAs<FunctionProtoType>();
343  CanQual<FunctionProtoType> ContextTy
344    = S.Context.getCanonicalType(Context->getType())
345         ->getAs<FunctionProtoType>();
346
347  // There isn't any way that I know of to add qualifiers
348  // during instantiation.
349  if (FriendTy.getQualifiers() != ContextTy.getQualifiers())
350    return false;
351
352  if (FriendTy->getNumArgs() != ContextTy->getNumArgs())
353    return false;
354
355  if (!MightInstantiateTo(S,
356                          ContextTy->getResultType(),
357                          FriendTy->getResultType()))
358    return false;
359
360  for (unsigned I = 0, E = FriendTy->getNumArgs(); I != E; ++I)
361    if (!MightInstantiateTo(S,
362                            ContextTy->getArgType(I),
363                            FriendTy->getArgType(I)))
364      return false;
365
366  return true;
367}
368
369static bool MightInstantiateTo(Sema &S,
370                               FunctionTemplateDecl *Context,
371                               FunctionTemplateDecl *Friend) {
372  return MightInstantiateTo(S,
373                            Context->getTemplatedDecl(),
374                            Friend->getTemplatedDecl());
375}
376
377static AccessResult MatchesFriend(Sema &S,
378                                  const EffectiveContext &EC,
379                                  const CXXRecordDecl *Friend) {
380  if (EC.includesClass(Friend))
381    return AR_accessible;
382
383  if (EC.isDependent()) {
384    CanQualType FriendTy
385      = S.Context.getCanonicalType(S.Context.getTypeDeclType(Friend));
386
387    for (EffectiveContext::record_iterator
388           I = EC.Records.begin(), E = EC.Records.end(); I != E; ++I) {
389      CanQualType ContextTy
390        = S.Context.getCanonicalType(S.Context.getTypeDeclType(*I));
391      if (MightInstantiateTo(S, ContextTy, FriendTy))
392        return AR_dependent;
393    }
394  }
395
396  return AR_inaccessible;
397}
398
399static AccessResult MatchesFriend(Sema &S,
400                                  const EffectiveContext &EC,
401                                  CanQualType Friend) {
402  if (const RecordType *RT = Friend->getAs<RecordType>())
403    return MatchesFriend(S, EC, cast<CXXRecordDecl>(RT->getDecl()));
404
405  // TODO: we can do better than this
406  if (Friend->isDependentType())
407    return AR_dependent;
408
409  return AR_inaccessible;
410}
411
412/// Determines whether the given friend class template matches
413/// anything in the effective context.
414static AccessResult MatchesFriend(Sema &S,
415                                  const EffectiveContext &EC,
416                                  ClassTemplateDecl *Friend) {
417  AccessResult OnFailure = AR_inaccessible;
418
419  // Check whether the friend is the template of a class in the
420  // context chain.
421  for (llvm::SmallVectorImpl<CXXRecordDecl*>::const_iterator
422         I = EC.Records.begin(), E = EC.Records.end(); I != E; ++I) {
423    CXXRecordDecl *Record = *I;
424
425    // Figure out whether the current class has a template:
426    ClassTemplateDecl *CTD;
427
428    // A specialization of the template...
429    if (isa<ClassTemplateSpecializationDecl>(Record)) {
430      CTD = cast<ClassTemplateSpecializationDecl>(Record)
431        ->getSpecializedTemplate();
432
433    // ... or the template pattern itself.
434    } else {
435      CTD = Record->getDescribedClassTemplate();
436      if (!CTD) continue;
437    }
438
439    // It's a match.
440    if (Friend == CTD->getCanonicalDecl())
441      return AR_accessible;
442
443    // If the context isn't dependent, it can't be a dependent match.
444    if (!EC.isDependent())
445      continue;
446
447    // If the template names don't match, it can't be a dependent
448    // match.  This isn't true in C++0x because of template aliases.
449    if (!S.LangOpts.CPlusPlus0x && CTD->getDeclName() != Friend->getDeclName())
450      continue;
451
452    // If the class's context can't instantiate to the friend's
453    // context, it can't be a dependent match.
454    if (!MightInstantiateTo(S, CTD->getDeclContext(),
455                            Friend->getDeclContext()))
456      continue;
457
458    // Otherwise, it's a dependent match.
459    OnFailure = AR_dependent;
460  }
461
462  return OnFailure;
463}
464
465/// Determines whether the given friend function matches anything in
466/// the effective context.
467static AccessResult MatchesFriend(Sema &S,
468                                  const EffectiveContext &EC,
469                                  FunctionDecl *Friend) {
470  AccessResult OnFailure = AR_inaccessible;
471
472  for (llvm::SmallVectorImpl<FunctionDecl*>::const_iterator
473         I = EC.Functions.begin(), E = EC.Functions.end(); I != E; ++I) {
474    if (Friend == *I)
475      return AR_accessible;
476
477    if (EC.isDependent() && MightInstantiateTo(S, *I, Friend))
478      OnFailure = AR_dependent;
479  }
480
481  return OnFailure;
482}
483
484/// Determines whether the given friend function template matches
485/// anything in the effective context.
486static AccessResult MatchesFriend(Sema &S,
487                                  const EffectiveContext &EC,
488                                  FunctionTemplateDecl *Friend) {
489  if (EC.Functions.empty()) return AR_inaccessible;
490
491  AccessResult OnFailure = AR_inaccessible;
492
493  for (llvm::SmallVectorImpl<FunctionDecl*>::const_iterator
494         I = EC.Functions.begin(), E = EC.Functions.end(); I != E; ++I) {
495
496    FunctionTemplateDecl *FTD = (*I)->getPrimaryTemplate();
497    if (!FTD)
498      FTD = (*I)->getDescribedFunctionTemplate();
499    if (!FTD)
500      continue;
501
502    FTD = FTD->getCanonicalDecl();
503
504    if (Friend == FTD)
505      return AR_accessible;
506
507    if (EC.isDependent() && MightInstantiateTo(S, FTD, Friend))
508      OnFailure = AR_dependent;
509  }
510
511  return OnFailure;
512}
513
514/// Determines whether the given friend declaration matches anything
515/// in the effective context.
516static AccessResult MatchesFriend(Sema &S,
517                                  const EffectiveContext &EC,
518                                  FriendDecl *FriendD) {
519  if (TypeSourceInfo *T = FriendD->getFriendType())
520    return MatchesFriend(S, EC, T->getType()->getCanonicalTypeUnqualified());
521
522  NamedDecl *Friend
523    = cast<NamedDecl>(FriendD->getFriendDecl()->getCanonicalDecl());
524
525  // FIXME: declarations with dependent or templated scope.
526
527  if (isa<ClassTemplateDecl>(Friend))
528    return MatchesFriend(S, EC, cast<ClassTemplateDecl>(Friend));
529
530  if (isa<FunctionTemplateDecl>(Friend))
531    return MatchesFriend(S, EC, cast<FunctionTemplateDecl>(Friend));
532
533  if (isa<CXXRecordDecl>(Friend))
534    return MatchesFriend(S, EC, cast<CXXRecordDecl>(Friend));
535
536  assert(isa<FunctionDecl>(Friend) && "unknown friend decl kind");
537  return MatchesFriend(S, EC, cast<FunctionDecl>(Friend));
538}
539
540static AccessResult GetFriendKind(Sema &S,
541                                  const EffectiveContext &EC,
542                                  const CXXRecordDecl *Class) {
543  AccessResult OnFailure = AR_inaccessible;
544
545  // Okay, check friends.
546  for (CXXRecordDecl::friend_iterator I = Class->friend_begin(),
547         E = Class->friend_end(); I != E; ++I) {
548    FriendDecl *Friend = *I;
549
550    switch (MatchesFriend(S, EC, Friend)) {
551    case AR_accessible:
552      return AR_accessible;
553
554    case AR_inaccessible:
555      continue;
556
557    case AR_dependent:
558      OnFailure = AR_dependent;
559      break;
560    }
561  }
562
563  // That's it, give up.
564  return OnFailure;
565}
566
567static AccessResult HasAccess(Sema &S,
568                              const EffectiveContext &EC,
569                              const CXXRecordDecl *NamingClass,
570                              AccessSpecifier Access,
571                              const AccessTarget &Target) {
572  assert(NamingClass->getCanonicalDecl() == NamingClass &&
573         "declaration should be canonicalized before being passed here");
574
575  if (Access == AS_public) return AR_accessible;
576  assert(Access == AS_private || Access == AS_protected);
577
578  AccessResult OnFailure = AR_inaccessible;
579
580  for (EffectiveContext::record_iterator
581         I = EC.Records.begin(), E = EC.Records.end(); I != E; ++I) {
582    // All the declarations in EC have been canonicalized, so pointer
583    // equality from this point on will work fine.
584    const CXXRecordDecl *ECRecord = *I;
585
586    // [B2] and [M2]
587    if (Access == AS_private) {
588      if (ECRecord == NamingClass)
589        return AR_accessible;
590
591      if (EC.isDependent() && MightInstantiateTo(ECRecord, NamingClass))
592        OnFailure = AR_dependent;
593
594    // [B3] and [M3]
595    } else {
596      assert(Access == AS_protected);
597      switch (IsDerivedFromInclusive(ECRecord, NamingClass)) {
598      case AR_accessible: break;
599      case AR_inaccessible: continue;
600      case AR_dependent: OnFailure = AR_dependent; continue;
601      }
602
603      if (!Target.hasInstanceContext())
604        return AR_accessible;
605
606      const CXXRecordDecl *InstanceContext = Target.resolveInstanceContext(S);
607      if (!InstanceContext) {
608        OnFailure = AR_dependent;
609        continue;
610      }
611
612      // C++ [class.protected]p1:
613      //   An additional access check beyond those described earlier in
614      //   [class.access] is applied when a non-static data member or
615      //   non-static member function is a protected member of its naming
616      //   class.  As described earlier, access to a protected member is
617      //   granted because the reference occurs in a friend or member of
618      //   some class C.  If the access is to form a pointer to member,
619      //   the nested-name-specifier shall name C or a class derived from
620      //   C. All other accesses involve a (possibly implicit) object
621      //   expression. In this case, the class of the object expression
622      //   shall be C or a class derived from C.
623      //
624      // We interpret this as a restriction on [M3].  Most of the
625      // conditions are encoded by not having any instance context.
626      switch (IsDerivedFromInclusive(InstanceContext, ECRecord)) {
627      case AR_accessible: return AR_accessible;
628      case AR_inaccessible: continue;
629      case AR_dependent: OnFailure = AR_dependent; continue;
630      }
631    }
632  }
633
634  if (!NamingClass->hasFriends())
635    return OnFailure;
636
637  // Don't consider friends if we're under the [class.protected]
638  // restriction, above.
639  if (Access == AS_protected && Target.hasInstanceContext()) {
640    const CXXRecordDecl *InstanceContext = Target.resolveInstanceContext(S);
641    if (!InstanceContext) return AR_dependent;
642
643    switch (IsDerivedFromInclusive(InstanceContext, NamingClass)) {
644    case AR_accessible: break;
645    case AR_inaccessible: return OnFailure;
646    case AR_dependent: return AR_dependent;
647    }
648  }
649
650  switch (GetFriendKind(S, EC, NamingClass)) {
651  case AR_accessible: return AR_accessible;
652  case AR_inaccessible: return OnFailure;
653  case AR_dependent: return AR_dependent;
654  }
655
656  // Silence bogus warnings
657  llvm_unreachable("impossible friendship kind");
658  return OnFailure;
659}
660
661/// Finds the best path from the naming class to the declaring class,
662/// taking friend declarations into account.
663///
664/// C++0x [class.access.base]p5:
665///   A member m is accessible at the point R when named in class N if
666///   [M1] m as a member of N is public, or
667///   [M2] m as a member of N is private, and R occurs in a member or
668///        friend of class N, or
669///   [M3] m as a member of N is protected, and R occurs in a member or
670///        friend of class N, or in a member or friend of a class P
671///        derived from N, where m as a member of P is public, private,
672///        or protected, or
673///   [M4] there exists a base class B of N that is accessible at R, and
674///        m is accessible at R when named in class B.
675///
676/// C++0x [class.access.base]p4:
677///   A base class B of N is accessible at R, if
678///   [B1] an invented public member of B would be a public member of N, or
679///   [B2] R occurs in a member or friend of class N, and an invented public
680///        member of B would be a private or protected member of N, or
681///   [B3] R occurs in a member or friend of a class P derived from N, and an
682///        invented public member of B would be a private or protected member
683///        of P, or
684///   [B4] there exists a class S such that B is a base class of S accessible
685///        at R and S is a base class of N accessible at R.
686///
687/// Along a single inheritance path we can restate both of these
688/// iteratively:
689///
690/// First, we note that M1-4 are equivalent to B1-4 if the member is
691/// treated as a notional base of its declaring class with inheritance
692/// access equivalent to the member's access.  Therefore we need only
693/// ask whether a class B is accessible from a class N in context R.
694///
695/// Let B_1 .. B_n be the inheritance path in question (i.e. where
696/// B_1 = N, B_n = B, and for all i, B_{i+1} is a direct base class of
697/// B_i).  For i in 1..n, we will calculate ACAB(i), the access to the
698/// closest accessible base in the path:
699///   Access(a, b) = (* access on the base specifier from a to b *)
700///   Merge(a, forbidden) = forbidden
701///   Merge(a, private) = forbidden
702///   Merge(a, b) = min(a,b)
703///   Accessible(c, forbidden) = false
704///   Accessible(c, private) = (R is c) || IsFriend(c, R)
705///   Accessible(c, protected) = (R derived from c) || IsFriend(c, R)
706///   Accessible(c, public) = true
707///   ACAB(n) = public
708///   ACAB(i) =
709///     let AccessToBase = Merge(Access(B_i, B_{i+1}), ACAB(i+1)) in
710///     if Accessible(B_i, AccessToBase) then public else AccessToBase
711///
712/// B is an accessible base of N at R iff ACAB(1) = public.
713///
714/// \param FinalAccess the access of the "final step", or AS_public if
715///   there is no final step.
716/// \return null if friendship is dependent
717static CXXBasePath *FindBestPath(Sema &S,
718                                 const EffectiveContext &EC,
719                                 AccessTarget &Target,
720                                 AccessSpecifier FinalAccess,
721                                 CXXBasePaths &Paths) {
722  // Derive the paths to the desired base.
723  const CXXRecordDecl *Derived = Target.getNamingClass();
724  const CXXRecordDecl *Base = Target.getDeclaringClass();
725
726  // FIXME: fail correctly when there are dependent paths.
727  bool isDerived = Derived->isDerivedFrom(const_cast<CXXRecordDecl*>(Base),
728                                          Paths);
729  assert(isDerived && "derived class not actually derived from base");
730  (void) isDerived;
731
732  CXXBasePath *BestPath = 0;
733
734  assert(FinalAccess != AS_none && "forbidden access after declaring class");
735
736  bool AnyDependent = false;
737
738  // Derive the friend-modified access along each path.
739  for (CXXBasePaths::paths_iterator PI = Paths.begin(), PE = Paths.end();
740         PI != PE; ++PI) {
741    AccessTarget::SavedInstanceContext _ = Target.saveInstanceContext();
742
743    // Walk through the path backwards.
744    AccessSpecifier PathAccess = FinalAccess;
745    CXXBasePath::iterator I = PI->end(), E = PI->begin();
746    while (I != E) {
747      --I;
748
749      assert(PathAccess != AS_none);
750
751      // If the declaration is a private member of a base class, there
752      // is no level of friendship in derived classes that can make it
753      // accessible.
754      if (PathAccess == AS_private) {
755        PathAccess = AS_none;
756        break;
757      }
758
759      const CXXRecordDecl *NC = I->Class->getCanonicalDecl();
760
761      AccessSpecifier BaseAccess = I->Base->getAccessSpecifier();
762      PathAccess = std::max(PathAccess, BaseAccess);
763
764      switch (HasAccess(S, EC, NC, PathAccess, Target)) {
765      case AR_inaccessible: break;
766      case AR_accessible:
767        PathAccess = AS_public;
768
769        // Future tests are not against members and so do not have
770        // instance context.
771        Target.suppressInstanceContext();
772        break;
773      case AR_dependent:
774        AnyDependent = true;
775        goto Next;
776      }
777    }
778
779    // Note that we modify the path's Access field to the
780    // friend-modified access.
781    if (BestPath == 0 || PathAccess < BestPath->Access) {
782      BestPath = &*PI;
783      BestPath->Access = PathAccess;
784
785      // Short-circuit if we found a public path.
786      if (BestPath->Access == AS_public)
787        return BestPath;
788    }
789
790  Next: ;
791  }
792
793  assert((!BestPath || BestPath->Access != AS_public) &&
794         "fell out of loop with public path");
795
796  // We didn't find a public path, but at least one path was subject
797  // to dependent friendship, so delay the check.
798  if (AnyDependent)
799    return 0;
800
801  return BestPath;
802}
803
804/// Diagnose the path which caused the given declaration or base class
805/// to become inaccessible.
806static void DiagnoseAccessPath(Sema &S,
807                               const EffectiveContext &EC,
808                               AccessTarget &Entity) {
809  AccessSpecifier Access = Entity.getAccess();
810  const CXXRecordDecl *NamingClass = Entity.getNamingClass();
811  NamingClass = NamingClass->getCanonicalDecl();
812
813  NamedDecl *D = (Entity.isMemberAccess() ? Entity.getTargetDecl() : 0);
814  const CXXRecordDecl *DeclaringClass = Entity.getDeclaringClass();
815
816  // Easy case: the decl's natural access determined its path access.
817  // We have to check against AS_private here in case Access is AS_none,
818  // indicating a non-public member of a private base class.
819  if (D && (Access == D->getAccess() || D->getAccess() == AS_private)) {
820    switch (HasAccess(S, EC, DeclaringClass, D->getAccess(), Entity)) {
821    case AR_inaccessible: {
822      S.Diag(D->getLocation(), diag::note_access_natural)
823        << (unsigned) (Access == AS_protected)
824        << /*FIXME: not implicitly*/ 0;
825      return;
826    }
827
828    case AR_accessible: break;
829
830    case AR_dependent:
831      llvm_unreachable("can't diagnose dependent access failures");
832      return;
833    }
834  }
835
836  CXXBasePaths Paths;
837  CXXBasePath &Path = *FindBestPath(S, EC, Entity, AS_public, Paths);
838
839  CXXBasePath::iterator I = Path.end(), E = Path.begin();
840  while (I != E) {
841    --I;
842
843    const CXXBaseSpecifier *BS = I->Base;
844    AccessSpecifier BaseAccess = BS->getAccessSpecifier();
845
846    // If this is public inheritance, or the derived class is a friend,
847    // skip this step.
848    if (BaseAccess == AS_public)
849      continue;
850
851    switch (GetFriendKind(S, EC, I->Class)) {
852    case AR_accessible: continue;
853    case AR_inaccessible: break;
854    case AR_dependent:
855      llvm_unreachable("can't diagnose dependent access failures");
856    }
857
858    // Check whether this base specifier is the tighest point
859    // constraining access.  We have to check against AS_private for
860    // the same reasons as above.
861    if (BaseAccess == AS_private || BaseAccess >= Access) {
862
863      // We're constrained by inheritance, but we want to say
864      // "declared private here" if we're diagnosing a hierarchy
865      // conversion and this is the final step.
866      unsigned diagnostic;
867      if (D) diagnostic = diag::note_access_constrained_by_path;
868      else if (I + 1 == Path.end()) diagnostic = diag::note_access_natural;
869      else diagnostic = diag::note_access_constrained_by_path;
870
871      S.Diag(BS->getSourceRange().getBegin(), diagnostic)
872        << BS->getSourceRange()
873        << (BaseAccess == AS_protected)
874        << (BS->getAccessSpecifierAsWritten() == AS_none);
875
876      if (D)
877        S.Diag(D->getLocation(), diag::note_field_decl);
878
879      return;
880    }
881  }
882
883  llvm_unreachable("access not apparently constrained by path");
884}
885
886static void DiagnoseBadAccess(Sema &S, SourceLocation Loc,
887                              const EffectiveContext &EC,
888                              AccessTarget &Entity) {
889  const CXXRecordDecl *NamingClass = Entity.getNamingClass();
890  const CXXRecordDecl *DeclaringClass = Entity.getDeclaringClass();
891  NamedDecl *D = (Entity.isMemberAccess() ? Entity.getTargetDecl() : 0);
892
893  S.Diag(Loc, Entity.getDiag())
894    << (Entity.getAccess() == AS_protected)
895    << (D ? D->getDeclName() : DeclarationName())
896    << S.Context.getTypeDeclType(NamingClass)
897    << S.Context.getTypeDeclType(DeclaringClass);
898  DiagnoseAccessPath(S, EC, Entity);
899}
900
901/// Determines whether the accessed entity is accessible.  Public members
902/// have been weeded out by this point.
903static AccessResult IsAccessible(Sema &S,
904                                 const EffectiveContext &EC,
905                                 AccessTarget &Entity) {
906  // Determine the actual naming class.
907  CXXRecordDecl *NamingClass = Entity.getNamingClass();
908  while (NamingClass->isAnonymousStructOrUnion())
909    NamingClass = cast<CXXRecordDecl>(NamingClass->getParent());
910  NamingClass = NamingClass->getCanonicalDecl();
911
912  AccessSpecifier UnprivilegedAccess = Entity.getAccess();
913  assert(UnprivilegedAccess != AS_public && "public access not weeded out");
914
915  // Before we try to recalculate access paths, try to white-list
916  // accesses which just trade in on the final step, i.e. accesses
917  // which don't require [M4] or [B4]. These are by far the most
918  // common forms of privileged access.
919  if (UnprivilegedAccess != AS_none) {
920    switch (HasAccess(S, EC, NamingClass, UnprivilegedAccess, Entity)) {
921    case AR_dependent:
922      // This is actually an interesting policy decision.  We don't
923      // *have* to delay immediately here: we can do the full access
924      // calculation in the hope that friendship on some intermediate
925      // class will make the declaration accessible non-dependently.
926      // But that's not cheap, and odds are very good (note: assertion
927      // made without data) that the friend declaration will determine
928      // access.
929      return AR_dependent;
930
931    case AR_accessible: return AR_accessible;
932    case AR_inaccessible: break;
933    }
934  }
935
936  AccessTarget::SavedInstanceContext _ = Entity.saveInstanceContext();
937
938  // We lower member accesses to base accesses by pretending that the
939  // member is a base class of its declaring class.
940  AccessSpecifier FinalAccess;
941
942  if (Entity.isMemberAccess()) {
943    // Determine if the declaration is accessible from EC when named
944    // in its declaring class.
945    NamedDecl *Target = Entity.getTargetDecl();
946    const CXXRecordDecl *DeclaringClass = Entity.getDeclaringClass();
947
948    FinalAccess = Target->getAccess();
949    switch (HasAccess(S, EC, DeclaringClass, FinalAccess, Entity)) {
950    case AR_accessible:
951      FinalAccess = AS_public;
952      break;
953    case AR_inaccessible: break;
954    case AR_dependent: return AR_dependent; // see above
955    }
956
957    if (DeclaringClass == NamingClass)
958      return (FinalAccess == AS_public ? AR_accessible : AR_inaccessible);
959
960    Entity.suppressInstanceContext();
961  } else {
962    FinalAccess = AS_public;
963  }
964
965  assert(Entity.getDeclaringClass() != NamingClass);
966
967  // Append the declaration's access if applicable.
968  CXXBasePaths Paths;
969  CXXBasePath *Path = FindBestPath(S, EC, Entity, FinalAccess, Paths);
970  if (!Path)
971    return AR_dependent;
972
973  assert(Path->Access <= UnprivilegedAccess &&
974         "access along best path worse than direct?");
975  if (Path->Access == AS_public)
976    return AR_accessible;
977  return AR_inaccessible;
978}
979
980static void DelayDependentAccess(Sema &S,
981                                 const EffectiveContext &EC,
982                                 SourceLocation Loc,
983                                 const AccessTarget &Entity) {
984  assert(EC.isDependent() && "delaying non-dependent access");
985  DeclContext *DC = EC.getInnerContext();
986  assert(DC->isDependentContext() && "delaying non-dependent access");
987  DependentDiagnostic::Create(S.Context, DC, DependentDiagnostic::Access,
988                              Loc,
989                              Entity.isMemberAccess(),
990                              Entity.getAccess(),
991                              Entity.getTargetDecl(),
992                              Entity.getNamingClass(),
993                              Entity.getBaseObjectType(),
994                              Entity.getDiag());
995}
996
997/// Checks access to an entity from the given effective context.
998static AccessResult CheckEffectiveAccess(Sema &S,
999                                         const EffectiveContext &EC,
1000                                         SourceLocation Loc,
1001                                         AccessTarget &Entity) {
1002  assert(Entity.getAccess() != AS_public && "called for public access!");
1003
1004  switch (IsAccessible(S, EC, Entity)) {
1005  case AR_dependent:
1006    DelayDependentAccess(S, EC, Loc, Entity);
1007    return AR_dependent;
1008
1009  case AR_inaccessible:
1010    if (!Entity.isQuiet())
1011      DiagnoseBadAccess(S, Loc, EC, Entity);
1012    return AR_inaccessible;
1013
1014  case AR_accessible:
1015    return AR_accessible;
1016  }
1017
1018  // silence unnecessary warning
1019  llvm_unreachable("invalid access result");
1020  return AR_accessible;
1021}
1022
1023static Sema::AccessResult CheckAccess(Sema &S, SourceLocation Loc,
1024                                      AccessTarget &Entity) {
1025  // If the access path is public, it's accessible everywhere.
1026  if (Entity.getAccess() == AS_public)
1027    return Sema::AR_accessible;
1028
1029  if (S.SuppressAccessChecking)
1030    return Sema::AR_accessible;
1031
1032  // If we're currently parsing a top-level declaration, delay
1033  // diagnostics.  This is the only case where parsing a declaration
1034  // can actually change our effective context for the purposes of
1035  // access control.
1036  if (S.CurContext->isFileContext() && S.ParsingDeclDepth) {
1037    S.DelayedDiagnostics.push_back(
1038        DelayedDiagnostic::makeAccess(Loc, Entity));
1039    return Sema::AR_delayed;
1040  }
1041
1042  EffectiveContext EC(S.CurContext);
1043  switch (CheckEffectiveAccess(S, EC, Loc, Entity)) {
1044  case AR_accessible: return Sema::AR_accessible;
1045  case AR_inaccessible: return Sema::AR_inaccessible;
1046  case AR_dependent: return Sema::AR_dependent;
1047  }
1048  llvm_unreachable("falling off end");
1049  return Sema::AR_accessible;
1050}
1051
1052void Sema::HandleDelayedAccessCheck(DelayedDiagnostic &DD, Decl *Ctx) {
1053  // Pretend we did this from the context of the newly-parsed
1054  // declaration. If that declaration itself forms a declaration context,
1055  // include it in the effective context so that parameters and return types of
1056  // befriended functions have that function's access priveledges.
1057  DeclContext *DC = Ctx->getDeclContext();
1058  if (isa<FunctionDecl>(Ctx))
1059    DC = cast<DeclContext>(Ctx);
1060  else if (FunctionTemplateDecl *FnTpl = dyn_cast<FunctionTemplateDecl>(Ctx))
1061    DC = cast<DeclContext>(FnTpl->getTemplatedDecl());
1062  EffectiveContext EC(DC);
1063
1064  AccessTarget Target(DD.getAccessData());
1065
1066  if (CheckEffectiveAccess(*this, EC, DD.Loc, Target) == ::AR_inaccessible)
1067    DD.Triggered = true;
1068}
1069
1070void Sema::HandleDependentAccessCheck(const DependentDiagnostic &DD,
1071                        const MultiLevelTemplateArgumentList &TemplateArgs) {
1072  SourceLocation Loc = DD.getAccessLoc();
1073  AccessSpecifier Access = DD.getAccess();
1074
1075  Decl *NamingD = FindInstantiatedDecl(Loc, DD.getAccessNamingClass(),
1076                                       TemplateArgs);
1077  if (!NamingD) return;
1078  Decl *TargetD = FindInstantiatedDecl(Loc, DD.getAccessTarget(),
1079                                       TemplateArgs);
1080  if (!TargetD) return;
1081
1082  if (DD.isAccessToMember()) {
1083    CXXRecordDecl *NamingClass = cast<CXXRecordDecl>(NamingD);
1084    NamedDecl *TargetDecl = cast<NamedDecl>(TargetD);
1085    QualType BaseObjectType = DD.getAccessBaseObjectType();
1086    if (!BaseObjectType.isNull()) {
1087      BaseObjectType = SubstType(BaseObjectType, TemplateArgs, Loc,
1088                                 DeclarationName());
1089      if (BaseObjectType.isNull()) return;
1090    }
1091
1092    AccessTarget Entity(Context,
1093                        AccessTarget::Member,
1094                        NamingClass,
1095                        DeclAccessPair::make(TargetDecl, Access),
1096                        BaseObjectType);
1097    Entity.setDiag(DD.getDiagnostic());
1098    CheckAccess(*this, Loc, Entity);
1099  } else {
1100    AccessTarget Entity(Context,
1101                        AccessTarget::Base,
1102                        cast<CXXRecordDecl>(TargetD),
1103                        cast<CXXRecordDecl>(NamingD),
1104                        Access);
1105    Entity.setDiag(DD.getDiagnostic());
1106    CheckAccess(*this, Loc, Entity);
1107  }
1108}
1109
1110Sema::AccessResult Sema::CheckUnresolvedLookupAccess(UnresolvedLookupExpr *E,
1111                                                     DeclAccessPair Found) {
1112  if (!getLangOptions().AccessControl ||
1113      !E->getNamingClass() ||
1114      Found.getAccess() == AS_public)
1115    return AR_accessible;
1116
1117  AccessTarget Entity(Context, AccessTarget::Member, E->getNamingClass(),
1118                      Found, QualType());
1119  Entity.setDiag(diag::err_access) << E->getSourceRange();
1120
1121  return CheckAccess(*this, E->getNameLoc(), Entity);
1122}
1123
1124/// Perform access-control checking on a previously-unresolved member
1125/// access which has now been resolved to a member.
1126Sema::AccessResult Sema::CheckUnresolvedMemberAccess(UnresolvedMemberExpr *E,
1127                                                     DeclAccessPair Found) {
1128  if (!getLangOptions().AccessControl ||
1129      Found.getAccess() == AS_public)
1130    return AR_accessible;
1131
1132  QualType BaseType = E->getBaseType();
1133  if (E->isArrow())
1134    BaseType = BaseType->getAs<PointerType>()->getPointeeType();
1135
1136  AccessTarget Entity(Context, AccessTarget::Member, E->getNamingClass(),
1137                      Found, BaseType);
1138  Entity.setDiag(diag::err_access) << E->getSourceRange();
1139
1140  return CheckAccess(*this, E->getMemberLoc(), Entity);
1141}
1142
1143Sema::AccessResult Sema::CheckDestructorAccess(SourceLocation Loc,
1144                                               CXXDestructorDecl *Dtor,
1145                                               const PartialDiagnostic &PDiag) {
1146  if (!getLangOptions().AccessControl)
1147    return AR_accessible;
1148
1149  // There's never a path involved when checking implicit destructor access.
1150  AccessSpecifier Access = Dtor->getAccess();
1151  if (Access == AS_public)
1152    return AR_accessible;
1153
1154  CXXRecordDecl *NamingClass = Dtor->getParent();
1155  AccessTarget Entity(Context, AccessTarget::Member, NamingClass,
1156                      DeclAccessPair::make(Dtor, Access),
1157                      QualType());
1158  Entity.setDiag(PDiag); // TODO: avoid copy
1159
1160  return CheckAccess(*this, Loc, Entity);
1161}
1162
1163/// Checks access to a constructor.
1164Sema::AccessResult Sema::CheckConstructorAccess(SourceLocation UseLoc,
1165                                                CXXConstructorDecl *Constructor,
1166                                                const InitializedEntity &Entity,
1167                                                AccessSpecifier Access,
1168                                                bool IsCopyBindingRefToTemp) {
1169  if (!getLangOptions().AccessControl ||
1170      Access == AS_public)
1171    return AR_accessible;
1172
1173  CXXRecordDecl *NamingClass = Constructor->getParent();
1174  AccessTarget AccessEntity(Context, AccessTarget::Member, NamingClass,
1175                            DeclAccessPair::make(Constructor, Access),
1176                            QualType());
1177  switch (Entity.getKind()) {
1178  default:
1179    AccessEntity.setDiag(IsCopyBindingRefToTemp
1180                         ? diag::ext_rvalue_to_reference_access_ctor
1181                         : diag::err_access_ctor);
1182    break;
1183
1184  case InitializedEntity::EK_Base:
1185    AccessEntity.setDiag(PDiag(diag::err_access_base)
1186                          << Entity.isInheritedVirtualBase()
1187                          << Entity.getBaseSpecifier()->getType()
1188                          << getSpecialMember(Constructor));
1189    break;
1190
1191  case InitializedEntity::EK_Member: {
1192    const FieldDecl *Field = cast<FieldDecl>(Entity.getDecl());
1193    AccessEntity.setDiag(PDiag(diag::err_access_field)
1194                          << Field->getType()
1195                          << getSpecialMember(Constructor));
1196    break;
1197  }
1198
1199  }
1200
1201  return CheckAccess(*this, UseLoc, AccessEntity);
1202}
1203
1204/// Checks direct (i.e. non-inherited) access to an arbitrary class
1205/// member.
1206Sema::AccessResult Sema::CheckDirectMemberAccess(SourceLocation UseLoc,
1207                                                 NamedDecl *Target,
1208                                           const PartialDiagnostic &Diag) {
1209  AccessSpecifier Access = Target->getAccess();
1210  if (!getLangOptions().AccessControl ||
1211      Access == AS_public)
1212    return AR_accessible;
1213
1214  CXXRecordDecl *NamingClass = cast<CXXRecordDecl>(Target->getDeclContext());
1215  AccessTarget Entity(Context, AccessTarget::Member, NamingClass,
1216                      DeclAccessPair::make(Target, Access),
1217                      QualType());
1218  Entity.setDiag(Diag);
1219  return CheckAccess(*this, UseLoc, Entity);
1220}
1221
1222
1223/// Checks access to an overloaded operator new or delete.
1224Sema::AccessResult Sema::CheckAllocationAccess(SourceLocation OpLoc,
1225                                               SourceRange PlacementRange,
1226                                               CXXRecordDecl *NamingClass,
1227                                               DeclAccessPair Found) {
1228  if (!getLangOptions().AccessControl ||
1229      !NamingClass ||
1230      Found.getAccess() == AS_public)
1231    return AR_accessible;
1232
1233  AccessTarget Entity(Context, AccessTarget::Member, NamingClass, Found,
1234                      QualType());
1235  Entity.setDiag(diag::err_access)
1236    << PlacementRange;
1237
1238  return CheckAccess(*this, OpLoc, Entity);
1239}
1240
1241/// Checks access to an overloaded member operator, including
1242/// conversion operators.
1243Sema::AccessResult Sema::CheckMemberOperatorAccess(SourceLocation OpLoc,
1244                                                   Expr *ObjectExpr,
1245                                                   Expr *ArgExpr,
1246                                                   DeclAccessPair Found) {
1247  if (!getLangOptions().AccessControl ||
1248      Found.getAccess() == AS_public)
1249    return AR_accessible;
1250
1251  const RecordType *RT = ObjectExpr->getType()->getAs<RecordType>();
1252  assert(RT && "found member operator but object expr not of record type");
1253  CXXRecordDecl *NamingClass = cast<CXXRecordDecl>(RT->getDecl());
1254
1255  AccessTarget Entity(Context, AccessTarget::Member, NamingClass, Found,
1256                      ObjectExpr->getType());
1257  Entity.setDiag(diag::err_access)
1258    << ObjectExpr->getSourceRange()
1259    << (ArgExpr ? ArgExpr->getSourceRange() : SourceRange());
1260
1261  return CheckAccess(*this, OpLoc, Entity);
1262}
1263
1264Sema::AccessResult Sema::CheckAddressOfMemberAccess(Expr *OvlExpr,
1265                                                    DeclAccessPair Found) {
1266  if (!getLangOptions().AccessControl ||
1267      Found.getAccess() == AS_none ||
1268      Found.getAccess() == AS_public)
1269    return AR_accessible;
1270
1271  OverloadExpr *Ovl = OverloadExpr::find(OvlExpr).getPointer();
1272  CXXRecordDecl *NamingClass = Ovl->getNamingClass();
1273
1274  AccessTarget Entity(Context, AccessTarget::Member, NamingClass, Found,
1275                      Context.getTypeDeclType(NamingClass));
1276  Entity.setDiag(diag::err_access)
1277    << Ovl->getSourceRange();
1278
1279  return CheckAccess(*this, Ovl->getNameLoc(), Entity);
1280}
1281
1282/// Checks access for a hierarchy conversion.
1283///
1284/// \param IsBaseToDerived whether this is a base-to-derived conversion (true)
1285///     or a derived-to-base conversion (false)
1286/// \param ForceCheck true if this check should be performed even if access
1287///     control is disabled;  some things rely on this for semantics
1288/// \param ForceUnprivileged true if this check should proceed as if the
1289///     context had no special privileges
1290/// \param ADK controls the kind of diagnostics that are used
1291Sema::AccessResult Sema::CheckBaseClassAccess(SourceLocation AccessLoc,
1292                                              QualType Base,
1293                                              QualType Derived,
1294                                              const CXXBasePath &Path,
1295                                              unsigned DiagID,
1296                                              bool ForceCheck,
1297                                              bool ForceUnprivileged) {
1298  if (!ForceCheck && !getLangOptions().AccessControl)
1299    return AR_accessible;
1300
1301  if (Path.Access == AS_public)
1302    return AR_accessible;
1303
1304  CXXRecordDecl *BaseD, *DerivedD;
1305  BaseD = cast<CXXRecordDecl>(Base->getAs<RecordType>()->getDecl());
1306  DerivedD = cast<CXXRecordDecl>(Derived->getAs<RecordType>()->getDecl());
1307
1308  AccessTarget Entity(Context, AccessTarget::Base, BaseD, DerivedD,
1309                      Path.Access);
1310  if (DiagID)
1311    Entity.setDiag(DiagID) << Derived << Base;
1312
1313  if (ForceUnprivileged) {
1314    switch (CheckEffectiveAccess(*this, EffectiveContext(),
1315                                 AccessLoc, Entity)) {
1316    case ::AR_accessible: return Sema::AR_accessible;
1317    case ::AR_inaccessible: return Sema::AR_inaccessible;
1318    case ::AR_dependent: return Sema::AR_dependent;
1319    }
1320    llvm_unreachable("unexpected result from CheckEffectiveAccess");
1321  }
1322  return CheckAccess(*this, AccessLoc, Entity);
1323}
1324
1325/// Checks access to all the declarations in the given result set.
1326void Sema::CheckLookupAccess(const LookupResult &R) {
1327  assert(getLangOptions().AccessControl
1328         && "performing access check without access control");
1329  assert(R.getNamingClass() && "performing access check without naming class");
1330
1331  for (LookupResult::iterator I = R.begin(), E = R.end(); I != E; ++I) {
1332    if (I.getAccess() != AS_public) {
1333      AccessTarget Entity(Context, AccessedEntity::Member,
1334                          R.getNamingClass(), I.getPair(),
1335                          R.getBaseObjectType());
1336      Entity.setDiag(diag::err_access);
1337
1338      CheckAccess(*this, R.getNameLoc(), Entity);
1339    }
1340  }
1341}
1342
1343void Sema::ActOnStartSuppressingAccessChecks() {
1344  assert(!SuppressAccessChecking &&
1345         "Tried to start access check suppression when already started.");
1346  SuppressAccessChecking = true;
1347}
1348
1349void Sema::ActOnStopSuppressingAccessChecks() {
1350  assert(SuppressAccessChecking &&
1351         "Tried to stop access check suprression when already stopped.");
1352  SuppressAccessChecking = false;
1353}
1354