SemaAccess.cpp revision 337ec3d0e8cb24a591ecbecdc0a995a167f6af01 
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  // Whitelist accesses if there's an invalid friend declaration.
520  if (FriendD->isInvalidDecl())
521    return AR_accessible;
522
523  if (TypeSourceInfo *T = FriendD->getFriendType())
524    return MatchesFriend(S, EC, T->getType()->getCanonicalTypeUnqualified());
525
526  NamedDecl *Friend
527    = cast<NamedDecl>(FriendD->getFriendDecl()->getCanonicalDecl());
528
529  // FIXME: declarations with dependent or templated scope.
530
531  if (isa<ClassTemplateDecl>(Friend))
532    return MatchesFriend(S, EC, cast<ClassTemplateDecl>(Friend));
533
534  if (isa<FunctionTemplateDecl>(Friend))
535    return MatchesFriend(S, EC, cast<FunctionTemplateDecl>(Friend));
536
537  if (isa<CXXRecordDecl>(Friend))
538    return MatchesFriend(S, EC, cast<CXXRecordDecl>(Friend));
539
540  assert(isa<FunctionDecl>(Friend) && "unknown friend decl kind");
541  return MatchesFriend(S, EC, cast<FunctionDecl>(Friend));
542}
543
544static AccessResult GetFriendKind(Sema &S,
545                                  const EffectiveContext &EC,
546                                  const CXXRecordDecl *Class) {
547  AccessResult OnFailure = AR_inaccessible;
548
549  // Okay, check friends.
550  for (CXXRecordDecl::friend_iterator I = Class->friend_begin(),
551         E = Class->friend_end(); I != E; ++I) {
552    FriendDecl *Friend = *I;
553
554    switch (MatchesFriend(S, EC, Friend)) {
555    case AR_accessible:
556      return AR_accessible;
557
558    case AR_inaccessible:
559      continue;
560
561    case AR_dependent:
562      OnFailure = AR_dependent;
563      break;
564    }
565  }
566
567  // That's it, give up.
568  return OnFailure;
569}
570
571namespace {
572
573/// A helper class for checking for a friend which will grant access
574/// to a protected instance member.
575struct ProtectedFriendContext {
576  Sema &S;
577  const EffectiveContext &EC;
578  const CXXRecordDecl *NamingClass;
579  bool CheckDependent;
580  bool EverDependent;
581
582  /// The path down to the current base class.
583  llvm::SmallVector<const CXXRecordDecl*, 20> CurPath;
584
585  ProtectedFriendContext(Sema &S, const EffectiveContext &EC,
586                         const CXXRecordDecl *InstanceContext,
587                         const CXXRecordDecl *NamingClass)
588    : S(S), EC(EC), NamingClass(NamingClass),
589      CheckDependent(InstanceContext->isDependentContext() ||
590                     NamingClass->isDependentContext()),
591      EverDependent(false) {}
592
593  /// Check classes in the current path for friendship, starting at
594  /// the given index.
595  bool checkFriendshipAlongPath(unsigned I) {
596    assert(I < CurPath.size());
597    for (unsigned E = CurPath.size(); I != E; ++I) {
598      switch (GetFriendKind(S, EC, CurPath[I])) {
599      case AR_accessible:   return true;
600      case AR_inaccessible: continue;
601      case AR_dependent:    EverDependent = true; continue;
602      }
603    }
604    return false;
605  }
606
607  /// Perform a search starting at the given class.
608  ///
609  /// PrivateDepth is the index of the last (least derived) class
610  /// along the current path such that a notional public member of
611  /// the final class in the path would have access in that class.
612  bool findFriendship(const CXXRecordDecl *Cur, unsigned PrivateDepth) {
613    // If we ever reach the naming class, check the current path for
614    // friendship.  We can also stop recursing because we obviously
615    // won't find the naming class there again.
616    if (Cur == NamingClass)
617      return checkFriendshipAlongPath(PrivateDepth);
618
619    if (CheckDependent && MightInstantiateTo(Cur, NamingClass))
620      EverDependent = true;
621
622    // Recurse into the base classes.
623    for (CXXRecordDecl::base_class_const_iterator
624           I = Cur->bases_begin(), E = Cur->bases_end(); I != E; ++I) {
625
626      // If this is private inheritance, then a public member of the
627      // base will not have any access in classes derived from Cur.
628      unsigned BasePrivateDepth = PrivateDepth;
629      if (I->getAccessSpecifier() == AS_private)
630        BasePrivateDepth = CurPath.size() - 1;
631
632      const CXXRecordDecl *RD;
633
634      QualType T = I->getType();
635      if (const RecordType *RT = T->getAs<RecordType>()) {
636        RD = cast<CXXRecordDecl>(RT->getDecl());
637      } else if (const InjectedClassNameType *IT
638                   = T->getAs<InjectedClassNameType>()) {
639        RD = IT->getDecl();
640      } else {
641        assert(T->isDependentType() && "non-dependent base wasn't a record?");
642        EverDependent = true;
643        continue;
644      }
645
646      // Recurse.  We don't need to clean up if this returns true.
647      CurPath.push_back(RD);
648      if (findFriendship(RD->getCanonicalDecl(), BasePrivateDepth))
649        return true;
650      CurPath.pop_back();
651    }
652
653    return false;
654  }
655
656  bool findFriendship(const CXXRecordDecl *Cur) {
657    assert(CurPath.empty());
658    CurPath.push_back(Cur);
659    return findFriendship(Cur, 0);
660  }
661};
662}
663
664/// Search for a class P that EC is a friend of, under the constraint
665///   InstanceContext <= P <= NamingClass
666/// and with the additional restriction that a protected member of
667/// NamingClass would have some natural access in P.
668///
669/// That second condition isn't actually quite right: the condition in
670/// the standard is whether the target would have some natural access
671/// in P.  The difference is that the target might be more accessible
672/// along some path not passing through NamingClass.  Allowing that
673/// introduces two problems:
674///   - It breaks encapsulation because you can suddenly access a
675///     forbidden base class's members by subclassing it elsewhere.
676///   - It makes access substantially harder to compute because it
677///     breaks the hill-climbing algorithm: knowing that the target is
678///     accessible in some base class would no longer let you change
679///     the question solely to whether the base class is accessible,
680///     because the original target might have been more accessible
681///     because of crazy subclassing.
682/// So we don't implement that.
683static AccessResult GetProtectedFriendKind(Sema &S, const EffectiveContext &EC,
684                                           const CXXRecordDecl *InstanceContext,
685                                           const CXXRecordDecl *NamingClass) {
686  assert(InstanceContext->getCanonicalDecl() == InstanceContext);
687  assert(NamingClass->getCanonicalDecl() == NamingClass);
688
689  ProtectedFriendContext PRC(S, EC, InstanceContext, NamingClass);
690  if (PRC.findFriendship(InstanceContext)) return AR_accessible;
691  if (PRC.EverDependent) return AR_dependent;
692  return AR_inaccessible;
693}
694
695static AccessResult HasAccess(Sema &S,
696                              const EffectiveContext &EC,
697                              const CXXRecordDecl *NamingClass,
698                              AccessSpecifier Access,
699                              const AccessTarget &Target) {
700  assert(NamingClass->getCanonicalDecl() == NamingClass &&
701         "declaration should be canonicalized before being passed here");
702
703  if (Access == AS_public) return AR_accessible;
704  assert(Access == AS_private || Access == AS_protected);
705
706  AccessResult OnFailure = AR_inaccessible;
707
708  for (EffectiveContext::record_iterator
709         I = EC.Records.begin(), E = EC.Records.end(); I != E; ++I) {
710    // All the declarations in EC have been canonicalized, so pointer
711    // equality from this point on will work fine.
712    const CXXRecordDecl *ECRecord = *I;
713
714    // [B2] and [M2]
715    if (Access == AS_private) {
716      if (ECRecord == NamingClass)
717        return AR_accessible;
718
719      if (EC.isDependent() && MightInstantiateTo(ECRecord, NamingClass))
720        OnFailure = AR_dependent;
721
722    // [B3] and [M3]
723    } else {
724      assert(Access == AS_protected);
725      switch (IsDerivedFromInclusive(ECRecord, NamingClass)) {
726      case AR_accessible: break;
727      case AR_inaccessible: continue;
728      case AR_dependent: OnFailure = AR_dependent; continue;
729      }
730
731      if (!Target.hasInstanceContext())
732        return AR_accessible;
733
734      const CXXRecordDecl *InstanceContext = Target.resolveInstanceContext(S);
735      if (!InstanceContext) {
736        OnFailure = AR_dependent;
737        continue;
738      }
739
740      // C++ [class.protected]p1:
741      //   An additional access check beyond those described earlier in
742      //   [class.access] is applied when a non-static data member or
743      //   non-static member function is a protected member of its naming
744      //   class.  As described earlier, access to a protected member is
745      //   granted because the reference occurs in a friend or member of
746      //   some class C.  If the access is to form a pointer to member,
747      //   the nested-name-specifier shall name C or a class derived from
748      //   C. All other accesses involve a (possibly implicit) object
749      //   expression. In this case, the class of the object expression
750      //   shall be C or a class derived from C.
751      //
752      // We interpret this as a restriction on [M3].  Most of the
753      // conditions are encoded by not having any instance context.
754      switch (IsDerivedFromInclusive(InstanceContext, ECRecord)) {
755      case AR_accessible: return AR_accessible;
756      case AR_inaccessible: continue;
757      case AR_dependent: OnFailure = AR_dependent; continue;
758      }
759    }
760  }
761
762  // [M3] and [B3] say that, if the target is protected in N, we grant
763  // access if the access occurs in a friend or member of some class P
764  // that's a subclass of N and where the target has some natural
765  // access in P.  The 'member' aspect is easy to handle because P
766  // would necessarily be one of the effective-context records, and we
767  // address that above.  The 'friend' aspect is completely ridiculous
768  // to implement because there are no restrictions at all on P
769  // *unless* the [class.protected] restriction applies.  If it does,
770  // however, we should ignore whether the naming class is a friend,
771  // and instead rely on whether any potential P is a friend.
772  if (Access == AS_protected && Target.hasInstanceContext()) {
773    const CXXRecordDecl *InstanceContext = Target.resolveInstanceContext(S);
774    if (!InstanceContext) return AR_dependent;
775    switch (GetProtectedFriendKind(S, EC, InstanceContext, NamingClass)) {
776    case AR_accessible: return AR_accessible;
777    case AR_inaccessible: return OnFailure;
778    case AR_dependent: return AR_dependent;
779    }
780    llvm_unreachable("impossible friendship kind");
781  }
782
783  switch (GetFriendKind(S, EC, NamingClass)) {
784  case AR_accessible: return AR_accessible;
785  case AR_inaccessible: return OnFailure;
786  case AR_dependent: return AR_dependent;
787  }
788
789  // Silence bogus warnings
790  llvm_unreachable("impossible friendship kind");
791  return OnFailure;
792}
793
794/// Finds the best path from the naming class to the declaring class,
795/// taking friend declarations into account.
796///
797/// C++0x [class.access.base]p5:
798///   A member m is accessible at the point R when named in class N if
799///   [M1] m as a member of N is public, or
800///   [M2] m as a member of N is private, and R occurs in a member or
801///        friend of class N, or
802///   [M3] m as a member of N is protected, and R occurs in a member or
803///        friend of class N, or in a member or friend of a class P
804///        derived from N, where m as a member of P is public, private,
805///        or protected, or
806///   [M4] there exists a base class B of N that is accessible at R, and
807///        m is accessible at R when named in class B.
808///
809/// C++0x [class.access.base]p4:
810///   A base class B of N is accessible at R, if
811///   [B1] an invented public member of B would be a public member of N, or
812///   [B2] R occurs in a member or friend of class N, and an invented public
813///        member of B would be a private or protected member of N, or
814///   [B3] R occurs in a member or friend of a class P derived from N, and an
815///        invented public member of B would be a private or protected member
816///        of P, or
817///   [B4] there exists a class S such that B is a base class of S accessible
818///        at R and S is a base class of N accessible at R.
819///
820/// Along a single inheritance path we can restate both of these
821/// iteratively:
822///
823/// First, we note that M1-4 are equivalent to B1-4 if the member is
824/// treated as a notional base of its declaring class with inheritance
825/// access equivalent to the member's access.  Therefore we need only
826/// ask whether a class B is accessible from a class N in context R.
827///
828/// Let B_1 .. B_n be the inheritance path in question (i.e. where
829/// B_1 = N, B_n = B, and for all i, B_{i+1} is a direct base class of
830/// B_i).  For i in 1..n, we will calculate ACAB(i), the access to the
831/// closest accessible base in the path:
832///   Access(a, b) = (* access on the base specifier from a to b *)
833///   Merge(a, forbidden) = forbidden
834///   Merge(a, private) = forbidden
835///   Merge(a, b) = min(a,b)
836///   Accessible(c, forbidden) = false
837///   Accessible(c, private) = (R is c) || IsFriend(c, R)
838///   Accessible(c, protected) = (R derived from c) || IsFriend(c, R)
839///   Accessible(c, public) = true
840///   ACAB(n) = public
841///   ACAB(i) =
842///     let AccessToBase = Merge(Access(B_i, B_{i+1}), ACAB(i+1)) in
843///     if Accessible(B_i, AccessToBase) then public else AccessToBase
844///
845/// B is an accessible base of N at R iff ACAB(1) = public.
846///
847/// \param FinalAccess the access of the "final step", or AS_public if
848///   there is no final step.
849/// \return null if friendship is dependent
850static CXXBasePath *FindBestPath(Sema &S,
851                                 const EffectiveContext &EC,
852                                 AccessTarget &Target,
853                                 AccessSpecifier FinalAccess,
854                                 CXXBasePaths &Paths) {
855  // Derive the paths to the desired base.
856  const CXXRecordDecl *Derived = Target.getNamingClass();
857  const CXXRecordDecl *Base = Target.getDeclaringClass();
858
859  // FIXME: fail correctly when there are dependent paths.
860  bool isDerived = Derived->isDerivedFrom(const_cast<CXXRecordDecl*>(Base),
861                                          Paths);
862  assert(isDerived && "derived class not actually derived from base");
863  (void) isDerived;
864
865  CXXBasePath *BestPath = 0;
866
867  assert(FinalAccess != AS_none && "forbidden access after declaring class");
868
869  bool AnyDependent = false;
870
871  // Derive the friend-modified access along each path.
872  for (CXXBasePaths::paths_iterator PI = Paths.begin(), PE = Paths.end();
873         PI != PE; ++PI) {
874    AccessTarget::SavedInstanceContext _ = Target.saveInstanceContext();
875
876    // Walk through the path backwards.
877    AccessSpecifier PathAccess = FinalAccess;
878    CXXBasePath::iterator I = PI->end(), E = PI->begin();
879    while (I != E) {
880      --I;
881
882      assert(PathAccess != AS_none);
883
884      // If the declaration is a private member of a base class, there
885      // is no level of friendship in derived classes that can make it
886      // accessible.
887      if (PathAccess == AS_private) {
888        PathAccess = AS_none;
889        break;
890      }
891
892      const CXXRecordDecl *NC = I->Class->getCanonicalDecl();
893
894      AccessSpecifier BaseAccess = I->Base->getAccessSpecifier();
895      PathAccess = std::max(PathAccess, BaseAccess);
896
897      switch (HasAccess(S, EC, NC, PathAccess, Target)) {
898      case AR_inaccessible: break;
899      case AR_accessible:
900        PathAccess = AS_public;
901
902        // Future tests are not against members and so do not have
903        // instance context.
904        Target.suppressInstanceContext();
905        break;
906      case AR_dependent:
907        AnyDependent = true;
908        goto Next;
909      }
910    }
911
912    // Note that we modify the path's Access field to the
913    // friend-modified access.
914    if (BestPath == 0 || PathAccess < BestPath->Access) {
915      BestPath = &*PI;
916      BestPath->Access = PathAccess;
917
918      // Short-circuit if we found a public path.
919      if (BestPath->Access == AS_public)
920        return BestPath;
921    }
922
923  Next: ;
924  }
925
926  assert((!BestPath || BestPath->Access != AS_public) &&
927         "fell out of loop with public path");
928
929  // We didn't find a public path, but at least one path was subject
930  // to dependent friendship, so delay the check.
931  if (AnyDependent)
932    return 0;
933
934  return BestPath;
935}
936
937/// Given that an entity has protected natural access, check whether
938/// access might be denied because of the protected member access
939/// restriction.
940///
941/// \return true if a note was emitted
942static bool TryDiagnoseProtectedAccess(Sema &S, const EffectiveContext &EC,
943                                       AccessTarget &Target) {
944  // Only applies to instance accesses.
945  if (!Target.hasInstanceContext())
946    return false;
947  assert(Target.isMemberAccess());
948  NamedDecl *D = Target.getTargetDecl();
949
950  const CXXRecordDecl *DeclaringClass = Target.getDeclaringClass();
951  DeclaringClass = DeclaringClass->getCanonicalDecl();
952
953  for (EffectiveContext::record_iterator
954         I = EC.Records.begin(), E = EC.Records.end(); I != E; ++I) {
955    const CXXRecordDecl *ECRecord = *I;
956    switch (IsDerivedFromInclusive(ECRecord, DeclaringClass)) {
957    case AR_accessible: break;
958    case AR_inaccessible: continue;
959    case AR_dependent: continue;
960    }
961
962    // The effective context is a subclass of the declaring class.
963    // If that class isn't a superclass of the instance context,
964    // then the [class.protected] restriction applies.
965
966    // To get this exactly right, this might need to be checked more
967    // holistically;  it's not necessarily the case that gaining
968    // access here would grant us access overall.
969
970    const CXXRecordDecl *InstanceContext = Target.resolveInstanceContext(S);
971    assert(InstanceContext && "diagnosing dependent access");
972
973    switch (IsDerivedFromInclusive(InstanceContext, ECRecord)) {
974    case AR_accessible: continue;
975    case AR_dependent: continue;
976    case AR_inaccessible:
977      S.Diag(D->getLocation(), diag::note_access_protected_restricted)
978        << (InstanceContext != Target.getNamingClass()->getCanonicalDecl())
979        << S.Context.getTypeDeclType(InstanceContext)
980        << S.Context.getTypeDeclType(ECRecord);
981      return true;
982    }
983  }
984
985  return false;
986}
987
988/// Diagnose the path which caused the given declaration or base class
989/// to become inaccessible.
990static void DiagnoseAccessPath(Sema &S,
991                               const EffectiveContext &EC,
992                               AccessTarget &Entity) {
993  AccessSpecifier Access = Entity.getAccess();
994  const CXXRecordDecl *NamingClass = Entity.getNamingClass();
995  NamingClass = NamingClass->getCanonicalDecl();
996
997  NamedDecl *D = (Entity.isMemberAccess() ? Entity.getTargetDecl() : 0);
998  const CXXRecordDecl *DeclaringClass = Entity.getDeclaringClass();
999
1000  // Easy case: the decl's natural access determined its path access.
1001  // We have to check against AS_private here in case Access is AS_none,
1002  // indicating a non-public member of a private base class.
1003  if (D && (Access == D->getAccess() || D->getAccess() == AS_private)) {
1004    switch (HasAccess(S, EC, DeclaringClass, D->getAccess(), Entity)) {
1005    case AR_inaccessible: {
1006      if (Access == AS_protected &&
1007          TryDiagnoseProtectedAccess(S, EC, Entity))
1008        return;
1009
1010      S.Diag(D->getLocation(), diag::note_access_natural)
1011        << (unsigned) (Access == AS_protected)
1012        << /*FIXME: not implicitly*/ 0;
1013      return;
1014    }
1015
1016    case AR_accessible: break;
1017
1018    case AR_dependent:
1019      llvm_unreachable("can't diagnose dependent access failures");
1020      return;
1021    }
1022  }
1023
1024  CXXBasePaths Paths;
1025  CXXBasePath &Path = *FindBestPath(S, EC, Entity, AS_public, Paths);
1026
1027  CXXBasePath::iterator I = Path.end(), E = Path.begin();
1028  while (I != E) {
1029    --I;
1030
1031    const CXXBaseSpecifier *BS = I->Base;
1032    AccessSpecifier BaseAccess = BS->getAccessSpecifier();
1033
1034    // If this is public inheritance, or the derived class is a friend,
1035    // skip this step.
1036    if (BaseAccess == AS_public)
1037      continue;
1038
1039    switch (GetFriendKind(S, EC, I->Class)) {
1040    case AR_accessible: continue;
1041    case AR_inaccessible: break;
1042    case AR_dependent:
1043      llvm_unreachable("can't diagnose dependent access failures");
1044    }
1045
1046    // Check whether this base specifier is the tighest point
1047    // constraining access.  We have to check against AS_private for
1048    // the same reasons as above.
1049    if (BaseAccess == AS_private || BaseAccess >= Access) {
1050
1051      // We're constrained by inheritance, but we want to say
1052      // "declared private here" if we're diagnosing a hierarchy
1053      // conversion and this is the final step.
1054      unsigned diagnostic;
1055      if (D) diagnostic = diag::note_access_constrained_by_path;
1056      else if (I + 1 == Path.end()) diagnostic = diag::note_access_natural;
1057      else diagnostic = diag::note_access_constrained_by_path;
1058
1059      S.Diag(BS->getSourceRange().getBegin(), diagnostic)
1060        << BS->getSourceRange()
1061        << (BaseAccess == AS_protected)
1062        << (BS->getAccessSpecifierAsWritten() == AS_none);
1063
1064      if (D)
1065        S.Diag(D->getLocation(), diag::note_field_decl);
1066
1067      return;
1068    }
1069  }
1070
1071  llvm_unreachable("access not apparently constrained by path");
1072}
1073
1074static void DiagnoseBadAccess(Sema &S, SourceLocation Loc,
1075                              const EffectiveContext &EC,
1076                              AccessTarget &Entity) {
1077  const CXXRecordDecl *NamingClass = Entity.getNamingClass();
1078  const CXXRecordDecl *DeclaringClass = Entity.getDeclaringClass();
1079  NamedDecl *D = (Entity.isMemberAccess() ? Entity.getTargetDecl() : 0);
1080
1081  S.Diag(Loc, Entity.getDiag())
1082    << (Entity.getAccess() == AS_protected)
1083    << (D ? D->getDeclName() : DeclarationName())
1084    << S.Context.getTypeDeclType(NamingClass)
1085    << S.Context.getTypeDeclType(DeclaringClass);
1086  DiagnoseAccessPath(S, EC, Entity);
1087}
1088
1089/// Determines whether the accessed entity is accessible.  Public members
1090/// have been weeded out by this point.
1091static AccessResult IsAccessible(Sema &S,
1092                                 const EffectiveContext &EC,
1093                                 AccessTarget &Entity) {
1094  // Determine the actual naming class.
1095  CXXRecordDecl *NamingClass = Entity.getNamingClass();
1096  while (NamingClass->isAnonymousStructOrUnion())
1097    NamingClass = cast<CXXRecordDecl>(NamingClass->getParent());
1098  NamingClass = NamingClass->getCanonicalDecl();
1099
1100  AccessSpecifier UnprivilegedAccess = Entity.getAccess();
1101  assert(UnprivilegedAccess != AS_public && "public access not weeded out");
1102
1103  // Before we try to recalculate access paths, try to white-list
1104  // accesses which just trade in on the final step, i.e. accesses
1105  // which don't require [M4] or [B4]. These are by far the most
1106  // common forms of privileged access.
1107  if (UnprivilegedAccess != AS_none) {
1108    switch (HasAccess(S, EC, NamingClass, UnprivilegedAccess, Entity)) {
1109    case AR_dependent:
1110      // This is actually an interesting policy decision.  We don't
1111      // *have* to delay immediately here: we can do the full access
1112      // calculation in the hope that friendship on some intermediate
1113      // class will make the declaration accessible non-dependently.
1114      // But that's not cheap, and odds are very good (note: assertion
1115      // made without data) that the friend declaration will determine
1116      // access.
1117      return AR_dependent;
1118
1119    case AR_accessible: return AR_accessible;
1120    case AR_inaccessible: break;
1121    }
1122  }
1123
1124  AccessTarget::SavedInstanceContext _ = Entity.saveInstanceContext();
1125
1126  // We lower member accesses to base accesses by pretending that the
1127  // member is a base class of its declaring class.
1128  AccessSpecifier FinalAccess;
1129
1130  if (Entity.isMemberAccess()) {
1131    // Determine if the declaration is accessible from EC when named
1132    // in its declaring class.
1133    NamedDecl *Target = Entity.getTargetDecl();
1134    const CXXRecordDecl *DeclaringClass = Entity.getDeclaringClass();
1135
1136    FinalAccess = Target->getAccess();
1137    switch (HasAccess(S, EC, DeclaringClass, FinalAccess, Entity)) {
1138    case AR_accessible:
1139      FinalAccess = AS_public;
1140      break;
1141    case AR_inaccessible: break;
1142    case AR_dependent: return AR_dependent; // see above
1143    }
1144
1145    if (DeclaringClass == NamingClass)
1146      return (FinalAccess == AS_public ? AR_accessible : AR_inaccessible);
1147
1148    Entity.suppressInstanceContext();
1149  } else {
1150    FinalAccess = AS_public;
1151  }
1152
1153  assert(Entity.getDeclaringClass() != NamingClass);
1154
1155  // Append the declaration's access if applicable.
1156  CXXBasePaths Paths;
1157  CXXBasePath *Path = FindBestPath(S, EC, Entity, FinalAccess, Paths);
1158  if (!Path)
1159    return AR_dependent;
1160
1161  assert(Path->Access <= UnprivilegedAccess &&
1162         "access along best path worse than direct?");
1163  if (Path->Access == AS_public)
1164    return AR_accessible;
1165  return AR_inaccessible;
1166}
1167
1168static void DelayDependentAccess(Sema &S,
1169                                 const EffectiveContext &EC,
1170                                 SourceLocation Loc,
1171                                 const AccessTarget &Entity) {
1172  assert(EC.isDependent() && "delaying non-dependent access");
1173  DeclContext *DC = EC.getInnerContext();
1174  assert(DC->isDependentContext() && "delaying non-dependent access");
1175  DependentDiagnostic::Create(S.Context, DC, DependentDiagnostic::Access,
1176                              Loc,
1177                              Entity.isMemberAccess(),
1178                              Entity.getAccess(),
1179                              Entity.getTargetDecl(),
1180                              Entity.getNamingClass(),
1181                              Entity.getBaseObjectType(),
1182                              Entity.getDiag());
1183}
1184
1185/// Checks access to an entity from the given effective context.
1186static AccessResult CheckEffectiveAccess(Sema &S,
1187                                         const EffectiveContext &EC,
1188                                         SourceLocation Loc,
1189                                         AccessTarget &Entity) {
1190  assert(Entity.getAccess() != AS_public && "called for public access!");
1191
1192  switch (IsAccessible(S, EC, Entity)) {
1193  case AR_dependent:
1194    DelayDependentAccess(S, EC, Loc, Entity);
1195    return AR_dependent;
1196
1197  case AR_inaccessible:
1198    if (!Entity.isQuiet())
1199      DiagnoseBadAccess(S, Loc, EC, Entity);
1200    return AR_inaccessible;
1201
1202  case AR_accessible:
1203    return AR_accessible;
1204  }
1205
1206  // silence unnecessary warning
1207  llvm_unreachable("invalid access result");
1208  return AR_accessible;
1209}
1210
1211static Sema::AccessResult CheckAccess(Sema &S, SourceLocation Loc,
1212                                      AccessTarget &Entity) {
1213  // If the access path is public, it's accessible everywhere.
1214  if (Entity.getAccess() == AS_public)
1215    return Sema::AR_accessible;
1216
1217  if (S.SuppressAccessChecking)
1218    return Sema::AR_accessible;
1219
1220  // If we're currently parsing a top-level declaration, delay
1221  // diagnostics.  This is the only case where parsing a declaration
1222  // can actually change our effective context for the purposes of
1223  // access control.
1224  if (S.CurContext->isFileContext() && S.ParsingDeclDepth) {
1225    S.DelayedDiagnostics.push_back(
1226        DelayedDiagnostic::makeAccess(Loc, Entity));
1227    return Sema::AR_delayed;
1228  }
1229
1230  EffectiveContext EC(S.CurContext);
1231  switch (CheckEffectiveAccess(S, EC, Loc, Entity)) {
1232  case AR_accessible: return Sema::AR_accessible;
1233  case AR_inaccessible: return Sema::AR_inaccessible;
1234  case AR_dependent: return Sema::AR_dependent;
1235  }
1236  llvm_unreachable("falling off end");
1237  return Sema::AR_accessible;
1238}
1239
1240void Sema::HandleDelayedAccessCheck(DelayedDiagnostic &DD, Decl *Ctx) {
1241  // Pretend we did this from the context of the newly-parsed
1242  // declaration. If that declaration itself forms a declaration context,
1243  // include it in the effective context so that parameters and return types of
1244  // befriended functions have that function's access priveledges.
1245  DeclContext *DC = Ctx->getDeclContext();
1246  if (isa<FunctionDecl>(Ctx))
1247    DC = cast<DeclContext>(Ctx);
1248  else if (FunctionTemplateDecl *FnTpl = dyn_cast<FunctionTemplateDecl>(Ctx))
1249    DC = cast<DeclContext>(FnTpl->getTemplatedDecl());
1250  EffectiveContext EC(DC);
1251
1252  AccessTarget Target(DD.getAccessData());
1253
1254  if (CheckEffectiveAccess(*this, EC, DD.Loc, Target) == ::AR_inaccessible)
1255    DD.Triggered = true;
1256}
1257
1258void Sema::HandleDependentAccessCheck(const DependentDiagnostic &DD,
1259                        const MultiLevelTemplateArgumentList &TemplateArgs) {
1260  SourceLocation Loc = DD.getAccessLoc();
1261  AccessSpecifier Access = DD.getAccess();
1262
1263  Decl *NamingD = FindInstantiatedDecl(Loc, DD.getAccessNamingClass(),
1264                                       TemplateArgs);
1265  if (!NamingD) return;
1266  Decl *TargetD = FindInstantiatedDecl(Loc, DD.getAccessTarget(),
1267                                       TemplateArgs);
1268  if (!TargetD) return;
1269
1270  if (DD.isAccessToMember()) {
1271    CXXRecordDecl *NamingClass = cast<CXXRecordDecl>(NamingD);
1272    NamedDecl *TargetDecl = cast<NamedDecl>(TargetD);
1273    QualType BaseObjectType = DD.getAccessBaseObjectType();
1274    if (!BaseObjectType.isNull()) {
1275      BaseObjectType = SubstType(BaseObjectType, TemplateArgs, Loc,
1276                                 DeclarationName());
1277      if (BaseObjectType.isNull()) return;
1278    }
1279
1280    AccessTarget Entity(Context,
1281                        AccessTarget::Member,
1282                        NamingClass,
1283                        DeclAccessPair::make(TargetDecl, Access),
1284                        BaseObjectType);
1285    Entity.setDiag(DD.getDiagnostic());
1286    CheckAccess(*this, Loc, Entity);
1287  } else {
1288    AccessTarget Entity(Context,
1289                        AccessTarget::Base,
1290                        cast<CXXRecordDecl>(TargetD),
1291                        cast<CXXRecordDecl>(NamingD),
1292                        Access);
1293    Entity.setDiag(DD.getDiagnostic());
1294    CheckAccess(*this, Loc, Entity);
1295  }
1296}
1297
1298Sema::AccessResult Sema::CheckUnresolvedLookupAccess(UnresolvedLookupExpr *E,
1299                                                     DeclAccessPair Found) {
1300  if (!getLangOptions().AccessControl ||
1301      !E->getNamingClass() ||
1302      Found.getAccess() == AS_public)
1303    return AR_accessible;
1304
1305  AccessTarget Entity(Context, AccessTarget::Member, E->getNamingClass(),
1306                      Found, QualType());
1307  Entity.setDiag(diag::err_access) << E->getSourceRange();
1308
1309  return CheckAccess(*this, E->getNameLoc(), Entity);
1310}
1311
1312/// Perform access-control checking on a previously-unresolved member
1313/// access which has now been resolved to a member.
1314Sema::AccessResult Sema::CheckUnresolvedMemberAccess(UnresolvedMemberExpr *E,
1315                                                     DeclAccessPair Found) {
1316  if (!getLangOptions().AccessControl ||
1317      Found.getAccess() == AS_public)
1318    return AR_accessible;
1319
1320  QualType BaseType = E->getBaseType();
1321  if (E->isArrow())
1322    BaseType = BaseType->getAs<PointerType>()->getPointeeType();
1323
1324  AccessTarget Entity(Context, AccessTarget::Member, E->getNamingClass(),
1325                      Found, BaseType);
1326  Entity.setDiag(diag::err_access) << E->getSourceRange();
1327
1328  return CheckAccess(*this, E->getMemberLoc(), Entity);
1329}
1330
1331Sema::AccessResult Sema::CheckDestructorAccess(SourceLocation Loc,
1332                                               CXXDestructorDecl *Dtor,
1333                                               const PartialDiagnostic &PDiag) {
1334  if (!getLangOptions().AccessControl)
1335    return AR_accessible;
1336
1337  // There's never a path involved when checking implicit destructor access.
1338  AccessSpecifier Access = Dtor->getAccess();
1339  if (Access == AS_public)
1340    return AR_accessible;
1341
1342  CXXRecordDecl *NamingClass = Dtor->getParent();
1343  AccessTarget Entity(Context, AccessTarget::Member, NamingClass,
1344                      DeclAccessPair::make(Dtor, Access),
1345                      QualType());
1346  Entity.setDiag(PDiag); // TODO: avoid copy
1347
1348  return CheckAccess(*this, Loc, Entity);
1349}
1350
1351/// Checks access to a constructor.
1352Sema::AccessResult Sema::CheckConstructorAccess(SourceLocation UseLoc,
1353                                                CXXConstructorDecl *Constructor,
1354                                                const InitializedEntity &Entity,
1355                                                AccessSpecifier Access,
1356                                                bool IsCopyBindingRefToTemp) {
1357  if (!getLangOptions().AccessControl ||
1358      Access == AS_public)
1359    return AR_accessible;
1360
1361  CXXRecordDecl *NamingClass = Constructor->getParent();
1362  AccessTarget AccessEntity(Context, AccessTarget::Member, NamingClass,
1363                            DeclAccessPair::make(Constructor, Access),
1364                            QualType());
1365  switch (Entity.getKind()) {
1366  default:
1367    AccessEntity.setDiag(IsCopyBindingRefToTemp
1368                         ? diag::ext_rvalue_to_reference_access_ctor
1369                         : diag::err_access_ctor);
1370    break;
1371
1372  case InitializedEntity::EK_Base:
1373    AccessEntity.setDiag(PDiag(diag::err_access_base)
1374                          << Entity.isInheritedVirtualBase()
1375                          << Entity.getBaseSpecifier()->getType()
1376                          << getSpecialMember(Constructor));
1377    break;
1378
1379  case InitializedEntity::EK_Member: {
1380    const FieldDecl *Field = cast<FieldDecl>(Entity.getDecl());
1381    AccessEntity.setDiag(PDiag(diag::err_access_field)
1382                          << Field->getType()
1383                          << getSpecialMember(Constructor));
1384    break;
1385  }
1386
1387  }
1388
1389  return CheckAccess(*this, UseLoc, AccessEntity);
1390}
1391
1392/// Checks direct (i.e. non-inherited) access to an arbitrary class
1393/// member.
1394Sema::AccessResult Sema::CheckDirectMemberAccess(SourceLocation UseLoc,
1395                                                 NamedDecl *Target,
1396                                           const PartialDiagnostic &Diag) {
1397  AccessSpecifier Access = Target->getAccess();
1398  if (!getLangOptions().AccessControl ||
1399      Access == AS_public)
1400    return AR_accessible;
1401
1402  CXXRecordDecl *NamingClass = cast<CXXRecordDecl>(Target->getDeclContext());
1403  AccessTarget Entity(Context, AccessTarget::Member, NamingClass,
1404                      DeclAccessPair::make(Target, Access),
1405                      QualType());
1406  Entity.setDiag(Diag);
1407  return CheckAccess(*this, UseLoc, Entity);
1408}
1409
1410
1411/// Checks access to an overloaded operator new or delete.
1412Sema::AccessResult Sema::CheckAllocationAccess(SourceLocation OpLoc,
1413                                               SourceRange PlacementRange,
1414                                               CXXRecordDecl *NamingClass,
1415                                               DeclAccessPair Found) {
1416  if (!getLangOptions().AccessControl ||
1417      !NamingClass ||
1418      Found.getAccess() == AS_public)
1419    return AR_accessible;
1420
1421  AccessTarget Entity(Context, AccessTarget::Member, NamingClass, Found,
1422                      QualType());
1423  Entity.setDiag(diag::err_access)
1424    << PlacementRange;
1425
1426  return CheckAccess(*this, OpLoc, Entity);
1427}
1428
1429/// Checks access to an overloaded member operator, including
1430/// conversion operators.
1431Sema::AccessResult Sema::CheckMemberOperatorAccess(SourceLocation OpLoc,
1432                                                   Expr *ObjectExpr,
1433                                                   Expr *ArgExpr,
1434                                                   DeclAccessPair Found) {
1435  if (!getLangOptions().AccessControl ||
1436      Found.getAccess() == AS_public)
1437    return AR_accessible;
1438
1439  const RecordType *RT = ObjectExpr->getType()->getAs<RecordType>();
1440  assert(RT && "found member operator but object expr not of record type");
1441  CXXRecordDecl *NamingClass = cast<CXXRecordDecl>(RT->getDecl());
1442
1443  AccessTarget Entity(Context, AccessTarget::Member, NamingClass, Found,
1444                      ObjectExpr->getType());
1445  Entity.setDiag(diag::err_access)
1446    << ObjectExpr->getSourceRange()
1447    << (ArgExpr ? ArgExpr->getSourceRange() : SourceRange());
1448
1449  return CheckAccess(*this, OpLoc, Entity);
1450}
1451
1452Sema::AccessResult Sema::CheckAddressOfMemberAccess(Expr *OvlExpr,
1453                                                    DeclAccessPair Found) {
1454  if (!getLangOptions().AccessControl ||
1455      Found.getAccess() == AS_none ||
1456      Found.getAccess() == AS_public)
1457    return AR_accessible;
1458
1459  OverloadExpr *Ovl = OverloadExpr::find(OvlExpr).Expression;
1460  CXXRecordDecl *NamingClass = Ovl->getNamingClass();
1461
1462  AccessTarget Entity(Context, AccessTarget::Member, NamingClass, Found,
1463                      Context.getTypeDeclType(NamingClass));
1464  Entity.setDiag(diag::err_access)
1465    << Ovl->getSourceRange();
1466
1467  return CheckAccess(*this, Ovl->getNameLoc(), Entity);
1468}
1469
1470/// Checks access for a hierarchy conversion.
1471///
1472/// \param IsBaseToDerived whether this is a base-to-derived conversion (true)
1473///     or a derived-to-base conversion (false)
1474/// \param ForceCheck true if this check should be performed even if access
1475///     control is disabled;  some things rely on this for semantics
1476/// \param ForceUnprivileged true if this check should proceed as if the
1477///     context had no special privileges
1478/// \param ADK controls the kind of diagnostics that are used
1479Sema::AccessResult Sema::CheckBaseClassAccess(SourceLocation AccessLoc,
1480                                              QualType Base,
1481                                              QualType Derived,
1482                                              const CXXBasePath &Path,
1483                                              unsigned DiagID,
1484                                              bool ForceCheck,
1485                                              bool ForceUnprivileged) {
1486  if (!ForceCheck && !getLangOptions().AccessControl)
1487    return AR_accessible;
1488
1489  if (Path.Access == AS_public)
1490    return AR_accessible;
1491
1492  CXXRecordDecl *BaseD, *DerivedD;
1493  BaseD = cast<CXXRecordDecl>(Base->getAs<RecordType>()->getDecl());
1494  DerivedD = cast<CXXRecordDecl>(Derived->getAs<RecordType>()->getDecl());
1495
1496  AccessTarget Entity(Context, AccessTarget::Base, BaseD, DerivedD,
1497                      Path.Access);
1498  if (DiagID)
1499    Entity.setDiag(DiagID) << Derived << Base;
1500
1501  if (ForceUnprivileged) {
1502    switch (CheckEffectiveAccess(*this, EffectiveContext(),
1503                                 AccessLoc, Entity)) {
1504    case ::AR_accessible: return Sema::AR_accessible;
1505    case ::AR_inaccessible: return Sema::AR_inaccessible;
1506    case ::AR_dependent: return Sema::AR_dependent;
1507    }
1508    llvm_unreachable("unexpected result from CheckEffectiveAccess");
1509  }
1510  return CheckAccess(*this, AccessLoc, Entity);
1511}
1512
1513/// Checks access to all the declarations in the given result set.
1514void Sema::CheckLookupAccess(const LookupResult &R) {
1515  assert(getLangOptions().AccessControl
1516         && "performing access check without access control");
1517  assert(R.getNamingClass() && "performing access check without naming class");
1518
1519  for (LookupResult::iterator I = R.begin(), E = R.end(); I != E; ++I) {
1520    if (I.getAccess() != AS_public) {
1521      AccessTarget Entity(Context, AccessedEntity::Member,
1522                          R.getNamingClass(), I.getPair(),
1523                          R.getBaseObjectType());
1524      Entity.setDiag(diag::err_access);
1525
1526      CheckAccess(*this, R.getNameLoc(), Entity);
1527    }
1528  }
1529}
1530
1531void Sema::ActOnStartSuppressingAccessChecks() {
1532  assert(!SuppressAccessChecking &&
1533         "Tried to start access check suppression when already started.");
1534  SuppressAccessChecking = true;
1535}
1536
1537void Sema::ActOnStopSuppressingAccessChecks() {
1538  assert(SuppressAccessChecking &&
1539         "Tried to stop access check suprression when already stopped.");
1540  SuppressAccessChecking = false;
1541}
1542