Add the clang library to the repo (with some of my changes, too).

1 files changed, 1850 insertions, 0 deletions

diff --git a/clang/lib/Sema/SemaAccess.cpp b/clang/lib/Sema/SemaAccess.cpp
new file mode 100644
index 0000000..01c141e
--- /dev/null
+++ b/clang/lib/Sema/SemaAccess.cpp
@@ -0,0 +1,1850 @@
+//===---- SemaAccess.cpp - C++ Access Control -------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file provides Sema routines for C++ access control semantics.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Sema/SemaInternal.h"
+#include "clang/Sema/DelayedDiagnostic.h"
+#include "clang/Sema/Initialization.h"
+#include "clang/Sema/Lookup.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/AST/CXXInheritance.h"
+#include "clang/AST/DeclCXX.h"
+#include "clang/AST/DeclFriend.h"
+#include "clang/AST/DeclObjC.h"
+#include "clang/AST/DependentDiagnostic.h"
+#include "clang/AST/ExprCXX.h"
+
+using namespace clang;
+using namespace sema;
+
+/// A copy of Sema's enum without AR_delayed.
+enum AccessResult {
+  AR_accessible,
+  AR_inaccessible,
+  AR_dependent
+};
+
+/// SetMemberAccessSpecifier - Set the access specifier of a member.
+/// Returns true on error (when the previous member decl access specifier
+/// is different from the new member decl access specifier).
+bool Sema::SetMemberAccessSpecifier(NamedDecl *MemberDecl,
+                                    NamedDecl *PrevMemberDecl,
+                                    AccessSpecifier LexicalAS) {
+  if (!PrevMemberDecl) {
+    // Use the lexical access specifier.
+    MemberDecl->setAccess(LexicalAS);
+    return false;
+  }
+
+  // C++ [class.access.spec]p3: When a member is redeclared its access
+  // specifier must be same as its initial declaration.
+  if (LexicalAS != AS_none && LexicalAS != PrevMemberDecl->getAccess()) {
+    Diag(MemberDecl->getLocation(),
+         diag::err_class_redeclared_with_different_access)
+      << MemberDecl << LexicalAS;
+    Diag(PrevMemberDecl->getLocation(), diag::note_previous_access_declaration)
+      << PrevMemberDecl << PrevMemberDecl->getAccess();
+
+    MemberDecl->setAccess(LexicalAS);
+    return true;
+  }
+
+  MemberDecl->setAccess(PrevMemberDecl->getAccess());
+  return false;
+}
+
+static CXXRecordDecl *FindDeclaringClass(NamedDecl *D) {
+  DeclContext *DC = D->getDeclContext();
+
+  // This can only happen at top: enum decls only "publish" their
+  // immediate members.
+  if (isa<EnumDecl>(DC))
+    DC = cast<EnumDecl>(DC)->getDeclContext();
+
+  CXXRecordDecl *DeclaringClass = cast<CXXRecordDecl>(DC);
+  while (DeclaringClass->isAnonymousStructOrUnion())
+    DeclaringClass = cast<CXXRecordDecl>(DeclaringClass->getDeclContext());
+  return DeclaringClass;
+}
+
+namespace {
+struct EffectiveContext {
+  EffectiveContext() : Inner(0), Dependent(false) {}
+
+  explicit EffectiveContext(DeclContext *DC)
+    : Inner(DC),
+      Dependent(DC->isDependentContext()) {
+
+    // C++ [class.access.nest]p1:
+    //   A nested class is a member and as such has the same access
+    //   rights as any other member.
+    // C++ [class.access]p2:
+    //   A member of a class can also access all the names to which
+    //   the class has access.  A local class of a member function
+    //   may access the same names that the member function itself
+    //   may access.
+    // This almost implies that the privileges of nesting are transitive.
+    // Technically it says nothing about the local classes of non-member
+    // functions (which can gain privileges through friendship), but we
+    // take that as an oversight.
+    while (true) {
+      if (isa<CXXRecordDecl>(DC)) {
+        CXXRecordDecl *Record = cast<CXXRecordDecl>(DC)->getCanonicalDecl();
+        Records.push_back(Record);
+        DC = Record->getDeclContext();
+      } else if (isa<FunctionDecl>(DC)) {
+        FunctionDecl *Function = cast<FunctionDecl>(DC)->getCanonicalDecl();
+        Functions.push_back(Function);
+        
+        if (Function->getFriendObjectKind())
+          DC = Function->getLexicalDeclContext();
+        else
+          DC = Function->getDeclContext();
+      } else if (DC->isFileContext()) {
+        break;
+      } else {
+        DC = DC->getParent();
+      }
+    }
+  }
+
+  bool isDependent() const { return Dependent; }
+
+  bool includesClass(const CXXRecordDecl *R) const {
+    R = R->getCanonicalDecl();
+    return std::find(Records.begin(), Records.end(), R)
+             != Records.end();
+  }
+
+  /// Retrieves the innermost "useful" context.  Can be null if we're
+  /// doing access-control without privileges.
+  DeclContext *getInnerContext() const {
+    return Inner;
+  }
+
+  typedef SmallVectorImpl<CXXRecordDecl*>::const_iterator record_iterator;
+
+  DeclContext *Inner;
+  SmallVector<FunctionDecl*, 4> Functions;
+  SmallVector<CXXRecordDecl*, 4> Records;
+  bool Dependent;
+};
+
+/// Like sema::AccessedEntity, but kindly lets us scribble all over
+/// it.
+struct AccessTarget : public AccessedEntity {
+  AccessTarget(const AccessedEntity &Entity)
+    : AccessedEntity(Entity) {
+    initialize();
+  }
+    
+  AccessTarget(ASTContext &Context, 
+               MemberNonce _,
+               CXXRecordDecl *NamingClass,
+               DeclAccessPair FoundDecl,
+               QualType BaseObjectType)
+    : AccessedEntity(Context, Member, NamingClass, FoundDecl, BaseObjectType) {
+    initialize();
+  }
+
+  AccessTarget(ASTContext &Context, 
+               BaseNonce _,
+               CXXRecordDecl *BaseClass,
+               CXXRecordDecl *DerivedClass,
+               AccessSpecifier Access)
+    : AccessedEntity(Context, Base, BaseClass, DerivedClass, Access) {
+    initialize();
+  }
+
+  bool isInstanceMember() const {
+    return (isMemberAccess() && getTargetDecl()->isCXXInstanceMember());
+  }
+
+  bool hasInstanceContext() const {
+    return HasInstanceContext;
+  }
+
+  class SavedInstanceContext {
+  public:
+    ~SavedInstanceContext() {
+      Target.HasInstanceContext = Has;
+    }
+
+  private:
+    friend struct AccessTarget;
+    explicit SavedInstanceContext(AccessTarget &Target)
+      : Target(Target), Has(Target.HasInstanceContext) {}
+    AccessTarget &Target;
+    bool Has;
+  };
+
+  SavedInstanceContext saveInstanceContext() {
+    return SavedInstanceContext(*this);
+  }
+
+  void suppressInstanceContext() {
+    HasInstanceContext = false;
+  }
+
+  const CXXRecordDecl *resolveInstanceContext(Sema &S) const {
+    assert(HasInstanceContext);
+    if (CalculatedInstanceContext)
+      return InstanceContext;
+
+    CalculatedInstanceContext = true;
+    DeclContext *IC = S.computeDeclContext(getBaseObjectType());
+    InstanceContext = (IC ? cast<CXXRecordDecl>(IC)->getCanonicalDecl() : 0);
+    return InstanceContext;
+  }
+
+  const CXXRecordDecl *getDeclaringClass() const {
+    return DeclaringClass;
+  }
+
+private:
+  void initialize() {
+    HasInstanceContext = (isMemberAccess() &&
+                          !getBaseObjectType().isNull() &&
+                          getTargetDecl()->isCXXInstanceMember());
+    CalculatedInstanceContext = false;
+    InstanceContext = 0;
+
+    if (isMemberAccess())
+      DeclaringClass = FindDeclaringClass(getTargetDecl());
+    else
+      DeclaringClass = getBaseClass();
+    DeclaringClass = DeclaringClass->getCanonicalDecl();
+  }
+
+  bool HasInstanceContext : 1;
+  mutable bool CalculatedInstanceContext : 1;
+  mutable const CXXRecordDecl *InstanceContext;
+  const CXXRecordDecl *DeclaringClass;
+};
+
+}
+
+/// Checks whether one class might instantiate to the other.
+static bool MightInstantiateTo(const CXXRecordDecl *From,
+                               const CXXRecordDecl *To) {
+  // Declaration names are always preserved by instantiation.
+  if (From->getDeclName() != To->getDeclName())
+    return false;
+
+  const DeclContext *FromDC = From->getDeclContext()->getPrimaryContext();
+  const DeclContext *ToDC = To->getDeclContext()->getPrimaryContext();
+  if (FromDC == ToDC) return true;
+  if (FromDC->isFileContext() || ToDC->isFileContext()) return false;
+
+  // Be conservative.
+  return true;
+}
+
+/// Checks whether one class is derived from another, inclusively.
+/// Properly indicates when it couldn't be determined due to
+/// dependence.
+///
+/// This should probably be donated to AST or at least Sema.
+static AccessResult IsDerivedFromInclusive(const CXXRecordDecl *Derived,
+                                           const CXXRecordDecl *Target) {
+  assert(Derived->getCanonicalDecl() == Derived);
+  assert(Target->getCanonicalDecl() == Target);
+
+  if (Derived == Target) return AR_accessible;
+
+  bool CheckDependent = Derived->isDependentContext();
+  if (CheckDependent && MightInstantiateTo(Derived, Target))
+    return AR_dependent;
+
+  AccessResult OnFailure = AR_inaccessible;
+  SmallVector<const CXXRecordDecl*, 8> Queue; // actually a stack
+
+  while (true) {
+    if (Derived->isDependentContext() && !Derived->hasDefinition())
+      return AR_dependent;
+    
+    for (CXXRecordDecl::base_class_const_iterator
+           I = Derived->bases_begin(), E = Derived->bases_end(); I != E; ++I) {
+
+      const CXXRecordDecl *RD;
+
+      QualType T = I->getType();
+      if (const RecordType *RT = T->getAs<RecordType>()) {
+        RD = cast<CXXRecordDecl>(RT->getDecl());
+      } else if (const InjectedClassNameType *IT
+                   = T->getAs<InjectedClassNameType>()) {
+        RD = IT->getDecl();
+      } else {
+        assert(T->isDependentType() && "non-dependent base wasn't a record?");
+        OnFailure = AR_dependent;
+        continue;
+      }
+
+      RD = RD->getCanonicalDecl();
+      if (RD == Target) return AR_accessible;
+      if (CheckDependent && MightInstantiateTo(RD, Target))
+        OnFailure = AR_dependent;
+
+      Queue.push_back(RD);
+    }
+
+    if (Queue.empty()) break;
+
+    Derived = Queue.back();
+    Queue.pop_back();
+  }
+
+  return OnFailure;
+}
+
+
+static bool MightInstantiateTo(Sema &S, DeclContext *Context,
+                               DeclContext *Friend) {
+  if (Friend == Context)
+    return true;
+
+  assert(!Friend->isDependentContext() &&
+         "can't handle friends with dependent contexts here");
+
+  if (!Context->isDependentContext())
+    return false;
+
+  if (Friend->isFileContext())
+    return false;
+
+  // TODO: this is very conservative
+  return true;
+}
+
+// Asks whether the type in 'context' can ever instantiate to the type
+// in 'friend'.
+static bool MightInstantiateTo(Sema &S, CanQualType Context, CanQualType Friend) {
+  if (Friend == Context)
+    return true;
+
+  if (!Friend->isDependentType() && !Context->isDependentType())
+    return false;
+
+  // TODO: this is very conservative.
+  return true;
+}
+
+static bool MightInstantiateTo(Sema &S,
+                               FunctionDecl *Context,
+                               FunctionDecl *Friend) {
+  if (Context->getDeclName() != Friend->getDeclName())
+    return false;
+
+  if (!MightInstantiateTo(S,
+                          Context->getDeclContext(),
+                          Friend->getDeclContext()))
+    return false;
+
+  CanQual<FunctionProtoType> FriendTy
+    = S.Context.getCanonicalType(Friend->getType())
+         ->getAs<FunctionProtoType>();
+  CanQual<FunctionProtoType> ContextTy
+    = S.Context.getCanonicalType(Context->getType())
+         ->getAs<FunctionProtoType>();
+
+  // There isn't any way that I know of to add qualifiers
+  // during instantiation.
+  if (FriendTy.getQualifiers() != ContextTy.getQualifiers())
+    return false;
+
+  if (FriendTy->getNumArgs() != ContextTy->getNumArgs())
+    return false;
+
+  if (!MightInstantiateTo(S,
+                          ContextTy->getResultType(),
+                          FriendTy->getResultType()))
+    return false;
+
+  for (unsigned I = 0, E = FriendTy->getNumArgs(); I != E; ++I)
+    if (!MightInstantiateTo(S,
+                            ContextTy->getArgType(I),
+                            FriendTy->getArgType(I)))
+      return false;
+
+  return true;
+}
+
+static bool MightInstantiateTo(Sema &S,
+                               FunctionTemplateDecl *Context,
+                               FunctionTemplateDecl *Friend) {
+  return MightInstantiateTo(S,
+                            Context->getTemplatedDecl(),
+                            Friend->getTemplatedDecl());
+}
+
+static AccessResult MatchesFriend(Sema &S,
+                                  const EffectiveContext &EC,
+                                  const CXXRecordDecl *Friend) {
+  if (EC.includesClass(Friend))
+    return AR_accessible;
+
+  if (EC.isDependent()) {
+    CanQualType FriendTy
+      = S.Context.getCanonicalType(S.Context.getTypeDeclType(Friend));
+
+    for (EffectiveContext::record_iterator
+           I = EC.Records.begin(), E = EC.Records.end(); I != E; ++I) {
+      CanQualType ContextTy
+        = S.Context.getCanonicalType(S.Context.getTypeDeclType(*I));
+      if (MightInstantiateTo(S, ContextTy, FriendTy))
+        return AR_dependent;
+    }
+  }
+
+  return AR_inaccessible;
+}
+
+static AccessResult MatchesFriend(Sema &S,
+                                  const EffectiveContext &EC,
+                                  CanQualType Friend) {
+  if (const RecordType *RT = Friend->getAs<RecordType>())
+    return MatchesFriend(S, EC, cast<CXXRecordDecl>(RT->getDecl()));
+
+  // TODO: we can do better than this
+  if (Friend->isDependentType())
+    return AR_dependent;
+
+  return AR_inaccessible;
+}
+
+/// Determines whether the given friend class template matches
+/// anything in the effective context.
+static AccessResult MatchesFriend(Sema &S,
+                                  const EffectiveContext &EC,
+                                  ClassTemplateDecl *Friend) {
+  AccessResult OnFailure = AR_inaccessible;
+
+  // Check whether the friend is the template of a class in the
+  // context chain.
+  for (SmallVectorImpl<CXXRecordDecl*>::const_iterator
+         I = EC.Records.begin(), E = EC.Records.end(); I != E; ++I) {
+    CXXRecordDecl *Record = *I;
+
+    // Figure out whether the current class has a template:
+    ClassTemplateDecl *CTD;
+
+    // A specialization of the template...
+    if (isa<ClassTemplateSpecializationDecl>(Record)) {
+      CTD = cast<ClassTemplateSpecializationDecl>(Record)
+        ->getSpecializedTemplate();
+
+    // ... or the template pattern itself.
+    } else {
+      CTD = Record->getDescribedClassTemplate();
+      if (!CTD) continue;
+    }
+
+    // It's a match.
+    if (Friend == CTD->getCanonicalDecl())
+      return AR_accessible;
+
+    // If the context isn't dependent, it can't be a dependent match.
+    if (!EC.isDependent())
+      continue;
+
+    // If the template names don't match, it can't be a dependent
+    // match.
+    if (CTD->getDeclName() != Friend->getDeclName())
+      continue;
+
+    // If the class's context can't instantiate to the friend's
+    // context, it can't be a dependent match.
+    if (!MightInstantiateTo(S, CTD->getDeclContext(),
+                            Friend->getDeclContext()))
+      continue;
+
+    // Otherwise, it's a dependent match.
+    OnFailure = AR_dependent;
+  }
+
+  return OnFailure;
+}
+
+/// Determines whether the given friend function matches anything in
+/// the effective context.
+static AccessResult MatchesFriend(Sema &S,
+                                  const EffectiveContext &EC,
+                                  FunctionDecl *Friend) {
+  AccessResult OnFailure = AR_inaccessible;
+
+  for (SmallVectorImpl<FunctionDecl*>::const_iterator
+         I = EC.Functions.begin(), E = EC.Functions.end(); I != E; ++I) {
+    if (Friend == *I)
+      return AR_accessible;
+
+    if (EC.isDependent() && MightInstantiateTo(S, *I, Friend))
+      OnFailure = AR_dependent;
+  }
+
+  return OnFailure;
+}
+
+/// Determines whether the given friend function template matches
+/// anything in the effective context.
+static AccessResult MatchesFriend(Sema &S,
+                                  const EffectiveContext &EC,
+                                  FunctionTemplateDecl *Friend) {
+  if (EC.Functions.empty()) return AR_inaccessible;
+
+  AccessResult OnFailure = AR_inaccessible;
+
+  for (SmallVectorImpl<FunctionDecl*>::const_iterator
+         I = EC.Functions.begin(), E = EC.Functions.end(); I != E; ++I) {
+
+    FunctionTemplateDecl *FTD = (*I)->getPrimaryTemplate();
+    if (!FTD)
+      FTD = (*I)->getDescribedFunctionTemplate();
+    if (!FTD)
+      continue;
+
+    FTD = FTD->getCanonicalDecl();
+
+    if (Friend == FTD)
+      return AR_accessible;
+
+    if (EC.isDependent() && MightInstantiateTo(S, FTD, Friend))
+      OnFailure = AR_dependent;
+  }
+
+  return OnFailure;
+}
+
+/// Determines whether the given friend declaration matches anything
+/// in the effective context.
+static AccessResult MatchesFriend(Sema &S,
+                                  const EffectiveContext &EC,
+                                  FriendDecl *FriendD) {
+  // Whitelist accesses if there's an invalid or unsupported friend
+  // declaration.
+  if (FriendD->isInvalidDecl() || FriendD->isUnsupportedFriend())
+    return AR_accessible;
+
+  if (TypeSourceInfo *T = FriendD->getFriendType())
+    return MatchesFriend(S, EC, T->getType()->getCanonicalTypeUnqualified());
+
+  NamedDecl *Friend
+    = cast<NamedDecl>(FriendD->getFriendDecl()->getCanonicalDecl());
+
+  // FIXME: declarations with dependent or templated scope.
+
+  if (isa<ClassTemplateDecl>(Friend))
+    return MatchesFriend(S, EC, cast<ClassTemplateDecl>(Friend));
+
+  if (isa<FunctionTemplateDecl>(Friend))
+    return MatchesFriend(S, EC, cast<FunctionTemplateDecl>(Friend));
+
+  if (isa<CXXRecordDecl>(Friend))
+    return MatchesFriend(S, EC, cast<CXXRecordDecl>(Friend));
+
+  assert(isa<FunctionDecl>(Friend) && "unknown friend decl kind");
+  return MatchesFriend(S, EC, cast<FunctionDecl>(Friend));
+}
+
+static AccessResult GetFriendKind(Sema &S,
+                                  const EffectiveContext &EC,
+                                  const CXXRecordDecl *Class) {
+  AccessResult OnFailure = AR_inaccessible;
+
+  // Okay, check friends.
+  for (CXXRecordDecl::friend_iterator I = Class->friend_begin(),
+         E = Class->friend_end(); I != E; ++I) {
+    FriendDecl *Friend = *I;
+
+    switch (MatchesFriend(S, EC, Friend)) {
+    case AR_accessible:
+      return AR_accessible;
+
+    case AR_inaccessible:
+      continue;
+
+    case AR_dependent:
+      OnFailure = AR_dependent;
+      break;
+    }
+  }
+
+  // That's it, give up.
+  return OnFailure;
+}
+
+namespace {
+
+/// A helper class for checking for a friend which will grant access
+/// to a protected instance member.
+struct ProtectedFriendContext {
+  Sema &S;
+  const EffectiveContext &EC;
+  const CXXRecordDecl *NamingClass;
+  bool CheckDependent;
+  bool EverDependent;
+
+  /// The path down to the current base class.
+  SmallVector<const CXXRecordDecl*, 20> CurPath;
+
+  ProtectedFriendContext(Sema &S, const EffectiveContext &EC,
+                         const CXXRecordDecl *InstanceContext,
+                         const CXXRecordDecl *NamingClass)
+    : S(S), EC(EC), NamingClass(NamingClass),
+      CheckDependent(InstanceContext->isDependentContext() ||
+                     NamingClass->isDependentContext()),
+      EverDependent(false) {}
+
+  /// Check classes in the current path for friendship, starting at
+  /// the given index.
+  bool checkFriendshipAlongPath(unsigned I) {
+    assert(I < CurPath.size());
+    for (unsigned E = CurPath.size(); I != E; ++I) {
+      switch (GetFriendKind(S, EC, CurPath[I])) {
+      case AR_accessible:   return true;
+      case AR_inaccessible: continue;
+      case AR_dependent:    EverDependent = true; continue;
+      }
+    }
+    return false;
+  }
+
+  /// Perform a search starting at the given class.
+  ///
+  /// PrivateDepth is the index of the last (least derived) class
+  /// along the current path such that a notional public member of
+  /// the final class in the path would have access in that class.
+  bool findFriendship(const CXXRecordDecl *Cur, unsigned PrivateDepth) {
+    // If we ever reach the naming class, check the current path for
+    // friendship.  We can also stop recursing because we obviously
+    // won't find the naming class there again.
+    if (Cur == NamingClass)
+      return checkFriendshipAlongPath(PrivateDepth);
+
+    if (CheckDependent && MightInstantiateTo(Cur, NamingClass))
+      EverDependent = true;
+
+    // Recurse into the base classes.
+    for (CXXRecordDecl::base_class_const_iterator
+           I = Cur->bases_begin(), E = Cur->bases_end(); I != E; ++I) {
+
+      // If this is private inheritance, then a public member of the
+      // base will not have any access in classes derived from Cur.
+      unsigned BasePrivateDepth = PrivateDepth;
+      if (I->getAccessSpecifier() == AS_private)
+        BasePrivateDepth = CurPath.size() - 1;
+
+      const CXXRecordDecl *RD;
+
+      QualType T = I->getType();
+      if (const RecordType *RT = T->getAs<RecordType>()) {
+        RD = cast<CXXRecordDecl>(RT->getDecl());
+      } else if (const InjectedClassNameType *IT
+                   = T->getAs<InjectedClassNameType>()) {
+        RD = IT->getDecl();
+      } else {
+        assert(T->isDependentType() && "non-dependent base wasn't a record?");
+        EverDependent = true;
+        continue;
+      }
+
+      // Recurse.  We don't need to clean up if this returns true.
+      CurPath.push_back(RD);
+      if (findFriendship(RD->getCanonicalDecl(), BasePrivateDepth))
+        return true;
+      CurPath.pop_back();
+    }
+
+    return false;
+  }
+
+  bool findFriendship(const CXXRecordDecl *Cur) {
+    assert(CurPath.empty());
+    CurPath.push_back(Cur);
+    return findFriendship(Cur, 0);
+  }
+};
+}
+
+/// Search for a class P that EC is a friend of, under the constraint
+///   InstanceContext <= P
+/// if InstanceContext exists, or else
+///   NamingClass <= P
+/// and with the additional restriction that a protected member of
+/// NamingClass would have some natural access in P, which implicitly
+/// imposes the constraint that P <= NamingClass.
+///
+/// This isn't quite the condition laid out in the standard.
+/// Instead of saying that a notional protected member of NamingClass
+/// would have to have some natural access in P, it says the actual
+/// target has to have some natural access in P, which opens up the
+/// possibility that the target (which is not necessarily a member
+/// of NamingClass) might be more accessible along some path not
+/// passing through it.  That's really a bad idea, though, because it
+/// introduces two problems:
+///   - Most importantly, it breaks encapsulation because you can
+///     access a forbidden base class's members by directly subclassing
+///     it elsewhere.
+///   - It also makes access substantially harder to compute because it
+///     breaks the hill-climbing algorithm: knowing that the target is
+///     accessible in some base class would no longer let you change
+///     the question solely to whether the base class is accessible,
+///     because the original target might have been more accessible
+///     because of crazy subclassing.
+/// So we don't implement that.
+static AccessResult GetProtectedFriendKind(Sema &S, const EffectiveContext &EC,
+                                           const CXXRecordDecl *InstanceContext,
+                                           const CXXRecordDecl *NamingClass) {
+  assert(InstanceContext == 0 ||
+         InstanceContext->getCanonicalDecl() == InstanceContext);
+  assert(NamingClass->getCanonicalDecl() == NamingClass);
+
+  // If we don't have an instance context, our constraints give us
+  // that NamingClass <= P <= NamingClass, i.e. P == NamingClass.
+  // This is just the usual friendship check.
+  if (!InstanceContext) return GetFriendKind(S, EC, NamingClass);
+
+  ProtectedFriendContext PRC(S, EC, InstanceContext, NamingClass);
+  if (PRC.findFriendship(InstanceContext)) return AR_accessible;
+  if (PRC.EverDependent) return AR_dependent;
+  return AR_inaccessible;
+}
+
+static AccessResult HasAccess(Sema &S,
+                              const EffectiveContext &EC,
+                              const CXXRecordDecl *NamingClass,
+                              AccessSpecifier Access,
+                              const AccessTarget &Target) {
+  assert(NamingClass->getCanonicalDecl() == NamingClass &&
+         "declaration should be canonicalized before being passed here");
+
+  if (Access == AS_public) return AR_accessible;
+  assert(Access == AS_private || Access == AS_protected);
+
+  AccessResult OnFailure = AR_inaccessible;
+
+  for (EffectiveContext::record_iterator
+         I = EC.Records.begin(), E = EC.Records.end(); I != E; ++I) {
+    // All the declarations in EC have been canonicalized, so pointer
+    // equality from this point on will work fine.
+    const CXXRecordDecl *ECRecord = *I;
+
+    // [B2] and [M2]
+    if (Access == AS_private) {
+      if (ECRecord == NamingClass)
+        return AR_accessible;
+
+      if (EC.isDependent() && MightInstantiateTo(ECRecord, NamingClass))
+        OnFailure = AR_dependent;
+
+    // [B3] and [M3]
+    } else {
+      assert(Access == AS_protected);
+      switch (IsDerivedFromInclusive(ECRecord, NamingClass)) {
+      case AR_accessible: break;
+      case AR_inaccessible: continue;
+      case AR_dependent: OnFailure = AR_dependent; continue;
+      }
+
+      // C++ [class.protected]p1:
+      //   An additional access check beyond those described earlier in
+      //   [class.access] is applied when a non-static data member or
+      //   non-static member function is a protected member of its naming
+      //   class.  As described earlier, access to a protected member is
+      //   granted because the reference occurs in a friend or member of
+      //   some class C.  If the access is to form a pointer to member,
+      //   the nested-name-specifier shall name C or a class derived from
+      //   C. All other accesses involve a (possibly implicit) object
+      //   expression. In this case, the class of the object expression
+      //   shall be C or a class derived from C.
+      //
+      // We interpret this as a restriction on [M3].
+
+      // In this part of the code, 'C' is just our context class ECRecord.
+      
+      // These rules are different if we don't have an instance context.
+      if (!Target.hasInstanceContext()) {
+        // If it's not an instance member, these restrictions don't apply.
+        if (!Target.isInstanceMember()) return AR_accessible;
+
+        // If it's an instance member, use the pointer-to-member rule
+        // that the naming class has to be derived from the effective
+        // context.
+
+        // Emulate a MSVC bug where the creation of pointer-to-member
+        // to protected member of base class is allowed but only from
+        // a static function member functions.
+        if (S.getLangOpts().MicrosoftMode && !EC.Functions.empty())
+          if (CXXMethodDecl* MD = dyn_cast<CXXMethodDecl>(EC.Functions.front()))
+            if (MD->isStatic()) return AR_accessible;
+
+        // Despite the standard's confident wording, there is a case
+        // where you can have an instance member that's neither in a
+        // pointer-to-member expression nor in a member access:  when
+        // it names a field in an unevaluated context that can't be an
+        // implicit member.  Pending clarification, we just apply the
+        // same naming-class restriction here.
+        //   FIXME: we're probably not correctly adding the
+        //   protected-member restriction when we retroactively convert
+        //   an expression to being evaluated.
+
+        // We know that ECRecord derives from NamingClass.  The
+        // restriction says to check whether NamingClass derives from
+        // ECRecord, but that's not really necessary: two distinct
+        // classes can't be recursively derived from each other.  So
+        // along this path, we just need to check whether the classes
+        // are equal.
+        if (NamingClass == ECRecord) return AR_accessible;
+
+        // Otherwise, this context class tells us nothing;  on to the next.
+        continue;
+      }
+
+      assert(Target.isInstanceMember());
+
+      const CXXRecordDecl *InstanceContext = Target.resolveInstanceContext(S);
+      if (!InstanceContext) {
+        OnFailure = AR_dependent;
+        continue;
+      }
+
+      switch (IsDerivedFromInclusive(InstanceContext, ECRecord)) {
+      case AR_accessible: return AR_accessible;
+      case AR_inaccessible: continue;
+      case AR_dependent: OnFailure = AR_dependent; continue;
+      }
+    }
+  }
+
+  // [M3] and [B3] say that, if the target is protected in N, we grant
+  // access if the access occurs in a friend or member of some class P
+  // that's a subclass of N and where the target has some natural
+  // access in P.  The 'member' aspect is easy to handle because P
+  // would necessarily be one of the effective-context records, and we
+  // address that above.  The 'friend' aspect is completely ridiculous
+  // to implement because there are no restrictions at all on P
+  // *unless* the [class.protected] restriction applies.  If it does,
+  // however, we should ignore whether the naming class is a friend,
+  // and instead rely on whether any potential P is a friend.
+  if (Access == AS_protected && Target.isInstanceMember()) {
+    // Compute the instance context if possible.
+    const CXXRecordDecl *InstanceContext = 0;
+    if (Target.hasInstanceContext()) {
+      InstanceContext = Target.resolveInstanceContext(S);
+      if (!InstanceContext) return AR_dependent;
+    }
+
+    switch (GetProtectedFriendKind(S, EC, InstanceContext, NamingClass)) {
+    case AR_accessible: return AR_accessible;
+    case AR_inaccessible: return OnFailure;
+    case AR_dependent: return AR_dependent;
+    }
+    llvm_unreachable("impossible friendship kind");
+  }
+
+  switch (GetFriendKind(S, EC, NamingClass)) {
+  case AR_accessible: return AR_accessible;
+  case AR_inaccessible: return OnFailure;
+  case AR_dependent: return AR_dependent;
+  }
+
+  // Silence bogus warnings
+  llvm_unreachable("impossible friendship kind");
+}
+
+/// Finds the best path from the naming class to the declaring class,
+/// taking friend declarations into account.
+///
+/// C++0x [class.access.base]p5:
+///   A member m is accessible at the point R when named in class N if
+///   [M1] m as a member of N is public, or
+///   [M2] m as a member of N is private, and R occurs in a member or
+///        friend of class N, or
+///   [M3] m as a member of N is protected, and R occurs in a member or
+///        friend of class N, or in a member or friend of a class P
+///        derived from N, where m as a member of P is public, private,
+///        or protected, or
+///   [M4] there exists a base class B of N that is accessible at R, and
+///        m is accessible at R when named in class B.
+///
+/// C++0x [class.access.base]p4:
+///   A base class B of N is accessible at R, if
+///   [B1] an invented public member of B would be a public member of N, or
+///   [B2] R occurs in a member or friend of class N, and an invented public
+///        member of B would be a private or protected member of N, or
+///   [B3] R occurs in a member or friend of a class P derived from N, and an
+///        invented public member of B would be a private or protected member
+///        of P, or
+///   [B4] there exists a class S such that B is a base class of S accessible
+///        at R and S is a base class of N accessible at R.
+///
+/// Along a single inheritance path we can restate both of these
+/// iteratively:
+///
+/// First, we note that M1-4 are equivalent to B1-4 if the member is
+/// treated as a notional base of its declaring class with inheritance
+/// access equivalent to the member's access.  Therefore we need only
+/// ask whether a class B is accessible from a class N in context R.
+///
+/// Let B_1 .. B_n be the inheritance path in question (i.e. where
+/// B_1 = N, B_n = B, and for all i, B_{i+1} is a direct base class of
+/// B_i).  For i in 1..n, we will calculate ACAB(i), the access to the
+/// closest accessible base in the path:
+///   Access(a, b) = (* access on the base specifier from a to b *)
+///   Merge(a, forbidden) = forbidden
+///   Merge(a, private) = forbidden
+///   Merge(a, b) = min(a,b)
+///   Accessible(c, forbidden) = false
+///   Accessible(c, private) = (R is c) || IsFriend(c, R)
+///   Accessible(c, protected) = (R derived from c) || IsFriend(c, R)
+///   Accessible(c, public) = true
+///   ACAB(n) = public
+///   ACAB(i) =
+///     let AccessToBase = Merge(Access(B_i, B_{i+1}), ACAB(i+1)) in
+///     if Accessible(B_i, AccessToBase) then public else AccessToBase
+///
+/// B is an accessible base of N at R iff ACAB(1) = public.
+///
+/// \param FinalAccess the access of the "final step", or AS_public if
+///   there is no final step.
+/// \return null if friendship is dependent
+static CXXBasePath *FindBestPath(Sema &S,
+                                 const EffectiveContext &EC,
+                                 AccessTarget &Target,
+                                 AccessSpecifier FinalAccess,
+                                 CXXBasePaths &Paths) {
+  // Derive the paths to the desired base.
+  const CXXRecordDecl *Derived = Target.getNamingClass();
+  const CXXRecordDecl *Base = Target.getDeclaringClass();
+
+  // FIXME: fail correctly when there are dependent paths.
+  bool isDerived = Derived->isDerivedFrom(const_cast<CXXRecordDecl*>(Base),
+                                          Paths);
+  assert(isDerived && "derived class not actually derived from base");
+  (void) isDerived;
+
+  CXXBasePath *BestPath = 0;
+
+  assert(FinalAccess != AS_none && "forbidden access after declaring class");
+
+  bool AnyDependent = false;
+
+  // Derive the friend-modified access along each path.
+  for (CXXBasePaths::paths_iterator PI = Paths.begin(), PE = Paths.end();
+         PI != PE; ++PI) {
+    AccessTarget::SavedInstanceContext _ = Target.saveInstanceContext();
+
+    // Walk through the path backwards.
+    AccessSpecifier PathAccess = FinalAccess;
+    CXXBasePath::iterator I = PI->end(), E = PI->begin();
+    while (I != E) {
+      --I;
+
+      assert(PathAccess != AS_none);
+
+      // If the declaration is a private member of a base class, there
+      // is no level of friendship in derived classes that can make it
+      // accessible.
+      if (PathAccess == AS_private) {
+        PathAccess = AS_none;
+        break;
+      }
+
+      const CXXRecordDecl *NC = I->Class->getCanonicalDecl();
+
+      AccessSpecifier BaseAccess = I->Base->getAccessSpecifier();
+      PathAccess = std::max(PathAccess, BaseAccess);
+
+      switch (HasAccess(S, EC, NC, PathAccess, Target)) {
+      case AR_inaccessible: break;
+      case AR_accessible:
+        PathAccess = AS_public;
+
+        // Future tests are not against members and so do not have
+        // instance context.
+        Target.suppressInstanceContext();
+        break;
+      case AR_dependent:
+        AnyDependent = true;
+        goto Next;
+      }
+    }
+
+    // Note that we modify the path's Access field to the
+    // friend-modified access.
+    if (BestPath == 0 || PathAccess < BestPath->Access) {
+      BestPath = &*PI;
+      BestPath->Access = PathAccess;
+
+      // Short-circuit if we found a public path.
+      if (BestPath->Access == AS_public)
+        return BestPath;
+    }
+
+  Next: ;
+  }
+
+  assert((!BestPath || BestPath->Access != AS_public) &&
+         "fell out of loop with public path");
+
+  // We didn't find a public path, but at least one path was subject
+  // to dependent friendship, so delay the check.
+  if (AnyDependent)
+    return 0;
+
+  return BestPath;
+}
+
+/// Given that an entity has protected natural access, check whether
+/// access might be denied because of the protected member access
+/// restriction.
+///
+/// \return true if a note was emitted
+static bool TryDiagnoseProtectedAccess(Sema &S, const EffectiveContext &EC,
+                                       AccessTarget &Target) {
+  // Only applies to instance accesses.
+  if (!Target.isInstanceMember())
+    return false;
+
+  assert(Target.isMemberAccess());
+
+  const CXXRecordDecl *NamingClass = Target.getNamingClass();
+  NamingClass = NamingClass->getCanonicalDecl();
+
+  for (EffectiveContext::record_iterator
+         I = EC.Records.begin(), E = EC.Records.end(); I != E; ++I) {
+    const CXXRecordDecl *ECRecord = *I;
+    switch (IsDerivedFromInclusive(ECRecord, NamingClass)) {
+    case AR_accessible: break;
+    case AR_inaccessible: continue;
+    case AR_dependent: continue;
+    }
+
+    // The effective context is a subclass of the declaring class.
+    // Check whether the [class.protected] restriction is limiting
+    // access.
+
+    // To get this exactly right, this might need to be checked more
+    // holistically;  it's not necessarily the case that gaining
+    // access here would grant us access overall.
+
+    NamedDecl *D = Target.getTargetDecl();
+
+    // If we don't have an instance context, [class.protected] says the
+    // naming class has to equal the context class.
+    if (!Target.hasInstanceContext()) {
+      // If it does, the restriction doesn't apply.
+      if (NamingClass == ECRecord) continue;
+
+      // TODO: it would be great to have a fixit here, since this is
+      // such an obvious error.
+      S.Diag(D->getLocation(), diag::note_access_protected_restricted_noobject)
+        << S.Context.getTypeDeclType(ECRecord);
+      return true;
+    }
+
+    const CXXRecordDecl *InstanceContext = Target.resolveInstanceContext(S);
+    assert(InstanceContext && "diagnosing dependent access");
+
+    switch (IsDerivedFromInclusive(InstanceContext, ECRecord)) {
+    case AR_accessible: continue;
+    case AR_dependent: continue;
+    case AR_inaccessible:
+      break;
+    }
+
+    // Okay, the restriction seems to be what's limiting us.
+
+    // Use a special diagnostic for constructors and destructors.
+    if (isa<CXXConstructorDecl>(D) || isa<CXXDestructorDecl>(D) ||
+        (isa<FunctionTemplateDecl>(D) &&
+         isa<CXXConstructorDecl>(
+                cast<FunctionTemplateDecl>(D)->getTemplatedDecl()))) {
+      S.Diag(D->getLocation(), diag::note_access_protected_restricted_ctordtor)
+        << isa<CXXDestructorDecl>(D);
+      return true;
+    }
+
+    // Otherwise, use the generic diagnostic.
+    S.Diag(D->getLocation(), diag::note_access_protected_restricted_object)
+      << S.Context.getTypeDeclType(ECRecord);
+    return true;
+  }
+
+  return false;
+}
+
+/// Diagnose the path which caused the given declaration or base class
+/// to become inaccessible.
+static void DiagnoseAccessPath(Sema &S,
+                               const EffectiveContext &EC,
+                               AccessTarget &Entity) {
+  AccessSpecifier Access = Entity.getAccess();
+
+  NamedDecl *D = (Entity.isMemberAccess() ? Entity.getTargetDecl() : 0);
+  const CXXRecordDecl *DeclaringClass = Entity.getDeclaringClass();
+
+  // Easy case: the decl's natural access determined its path access.
+  // We have to check against AS_private here in case Access is AS_none,
+  // indicating a non-public member of a private base class.
+  if (D && (Access == D->getAccess() || D->getAccess() == AS_private)) {
+    switch (HasAccess(S, EC, DeclaringClass, D->getAccess(), Entity)) {
+    case AR_inaccessible: {
+      if (Access == AS_protected &&
+          TryDiagnoseProtectedAccess(S, EC, Entity))
+        return;
+
+      // Find an original declaration.
+      while (D->isOutOfLine()) {
+        NamedDecl *PrevDecl = 0;
+        if (VarDecl *VD = dyn_cast<VarDecl>(D))
+          PrevDecl = VD->getPreviousDecl();
+        else if (FunctionDecl *FD = dyn_cast<FunctionDecl>(D))
+          PrevDecl = FD->getPreviousDecl();
+        else if (TypedefNameDecl *TND = dyn_cast<TypedefNameDecl>(D))
+          PrevDecl = TND->getPreviousDecl();
+        else if (TagDecl *TD = dyn_cast<TagDecl>(D)) {
+          if (isa<RecordDecl>(D) && cast<RecordDecl>(D)->isInjectedClassName())
+            break;
+          PrevDecl = TD->getPreviousDecl();
+        }
+        if (!PrevDecl) break;
+        D = PrevDecl;
+      }
+
+      CXXRecordDecl *DeclaringClass = FindDeclaringClass(D);
+      Decl *ImmediateChild;
+      if (D->getDeclContext() == DeclaringClass)
+        ImmediateChild = D;
+      else {
+        DeclContext *DC = D->getDeclContext();
+        while (DC->getParent() != DeclaringClass)
+          DC = DC->getParent();
+        ImmediateChild = cast<Decl>(DC);
+      }
+      
+      // Check whether there's an AccessSpecDecl preceding this in the
+      // chain of the DeclContext.
+      bool Implicit = true;
+      for (CXXRecordDecl::decl_iterator
+             I = DeclaringClass->decls_begin(), E = DeclaringClass->decls_end();
+           I != E; ++I) {
+        if (*I == ImmediateChild) break;
+        if (isa<AccessSpecDecl>(*I)) {
+          Implicit = false;
+          break;
+        }
+      }
+
+      S.Diag(D->getLocation(), diag::note_access_natural)
+        << (unsigned) (Access == AS_protected)
+        << Implicit;
+      return;
+    }
+
+    case AR_accessible: break;
+
+    case AR_dependent:
+      llvm_unreachable("can't diagnose dependent access failures");
+    }
+  }
+
+  CXXBasePaths Paths;
+  CXXBasePath &Path = *FindBestPath(S, EC, Entity, AS_public, Paths);
+
+  CXXBasePath::iterator I = Path.end(), E = Path.begin();
+  while (I != E) {
+    --I;
+
+    const CXXBaseSpecifier *BS = I->Base;
+    AccessSpecifier BaseAccess = BS->getAccessSpecifier();
+
+    // If this is public inheritance, or the derived class is a friend,
+    // skip this step.
+    if (BaseAccess == AS_public)
+      continue;
+
+    switch (GetFriendKind(S, EC, I->Class)) {
+    case AR_accessible: continue;
+    case AR_inaccessible: break;
+    case AR_dependent:
+      llvm_unreachable("can't diagnose dependent access failures");
+    }
+
+    // Check whether this base specifier is the tighest point
+    // constraining access.  We have to check against AS_private for
+    // the same reasons as above.
+    if (BaseAccess == AS_private || BaseAccess >= Access) {
+
+      // We're constrained by inheritance, but we want to say
+      // "declared private here" if we're diagnosing a hierarchy
+      // conversion and this is the final step.
+      unsigned diagnostic;
+      if (D) diagnostic = diag::note_access_constrained_by_path;
+      else if (I + 1 == Path.end()) diagnostic = diag::note_access_natural;
+      else diagnostic = diag::note_access_constrained_by_path;
+
+      S.Diag(BS->getSourceRange().getBegin(), diagnostic)
+        << BS->getSourceRange()
+        << (BaseAccess == AS_protected)
+        << (BS->getAccessSpecifierAsWritten() == AS_none);
+      
+      if (D)
+        S.Diag(D->getLocation(), diag::note_field_decl);
+      
+      return;
+    }
+  }
+
+  llvm_unreachable("access not apparently constrained by path");
+}
+
+static void DiagnoseBadAccess(Sema &S, SourceLocation Loc,
+                              const EffectiveContext &EC,
+                              AccessTarget &Entity) {
+  const CXXRecordDecl *NamingClass = Entity.getNamingClass();
+  const CXXRecordDecl *DeclaringClass = Entity.getDeclaringClass();
+  NamedDecl *D = (Entity.isMemberAccess() ? Entity.getTargetDecl() : 0);
+
+  S.Diag(Loc, Entity.getDiag())
+    << (Entity.getAccess() == AS_protected)
+    << (D ? D->getDeclName() : DeclarationName())
+    << S.Context.getTypeDeclType(NamingClass)
+    << S.Context.getTypeDeclType(DeclaringClass);
+  DiagnoseAccessPath(S, EC, Entity);
+}
+
+/// MSVC has a bug where if during an using declaration name lookup, 
+/// the declaration found is unaccessible (private) and that declaration 
+/// was bring into scope via another using declaration whose target
+/// declaration is accessible (public) then no error is generated.
+/// Example:
+///   class A {
+///   public:
+///     int f();
+///   };
+///   class B : public A {
+///   private:
+///     using A::f;
+///   };
+///   class C : public B {
+///   private:
+///     using B::f;
+///   };
+///
+/// Here, B::f is private so this should fail in Standard C++, but 
+/// because B::f refers to A::f which is public MSVC accepts it.
+static bool IsMicrosoftUsingDeclarationAccessBug(Sema& S, 
+                                                 SourceLocation AccessLoc,
+                                                 AccessTarget &Entity) {
+  if (UsingShadowDecl *Shadow =
+                         dyn_cast<UsingShadowDecl>(Entity.getTargetDecl())) {
+    const NamedDecl *OrigDecl = Entity.getTargetDecl()->getUnderlyingDecl();
+    if (Entity.getTargetDecl()->getAccess() == AS_private && 
+        (OrigDecl->getAccess() == AS_public ||
+         OrigDecl->getAccess() == AS_protected)) {
+      S.Diag(AccessLoc, diag::ext_ms_using_declaration_inaccessible)
+        << Shadow->getUsingDecl()->getQualifiedNameAsString()
+        << OrigDecl->getQualifiedNameAsString();
+      return true;
+    }
+  }
+  return false;
+}
+
+/// Determines whether the accessed entity is accessible.  Public members
+/// have been weeded out by this point.
+static AccessResult IsAccessible(Sema &S,
+                                 const EffectiveContext &EC,
+                                 AccessTarget &Entity) {
+  // Determine the actual naming class.
+  CXXRecordDecl *NamingClass = Entity.getNamingClass();
+  while (NamingClass->isAnonymousStructOrUnion())
+    NamingClass = cast<CXXRecordDecl>(NamingClass->getParent());
+  NamingClass = NamingClass->getCanonicalDecl();
+
+  AccessSpecifier UnprivilegedAccess = Entity.getAccess();
+  assert(UnprivilegedAccess != AS_public && "public access not weeded out");
+
+  // Before we try to recalculate access paths, try to white-list
+  // accesses which just trade in on the final step, i.e. accesses
+  // which don't require [M4] or [B4]. These are by far the most
+  // common forms of privileged access.
+  if (UnprivilegedAccess != AS_none) {
+    switch (HasAccess(S, EC, NamingClass, UnprivilegedAccess, Entity)) {
+    case AR_dependent:
+      // This is actually an interesting policy decision.  We don't
+      // *have* to delay immediately here: we can do the full access
+      // calculation in the hope that friendship on some intermediate
+      // class will make the declaration accessible non-dependently.
+      // But that's not cheap, and odds are very good (note: assertion
+      // made without data) that the friend declaration will determine
+      // access.
+      return AR_dependent;
+
+    case AR_accessible: return AR_accessible;
+    case AR_inaccessible: break;
+    }
+  }
+
+  AccessTarget::SavedInstanceContext _ = Entity.saveInstanceContext();
+
+  // We lower member accesses to base accesses by pretending that the
+  // member is a base class of its declaring class.
+  AccessSpecifier FinalAccess;
+
+  if (Entity.isMemberAccess()) {
+    // Determine if the declaration is accessible from EC when named
+    // in its declaring class.
+    NamedDecl *Target = Entity.getTargetDecl();
+    const CXXRecordDecl *DeclaringClass = Entity.getDeclaringClass();
+
+    FinalAccess = Target->getAccess();
+    switch (HasAccess(S, EC, DeclaringClass, FinalAccess, Entity)) {
+    case AR_accessible:
+      FinalAccess = AS_public;
+      break;
+    case AR_inaccessible: break;
+    case AR_dependent: return AR_dependent; // see above
+    }
+
+    if (DeclaringClass == NamingClass)
+      return (FinalAccess == AS_public ? AR_accessible : AR_inaccessible);
+
+    Entity.suppressInstanceContext();
+  } else {
+    FinalAccess = AS_public;
+  }
+
+  assert(Entity.getDeclaringClass() != NamingClass);
+
+  // Append the declaration's access if applicable.
+  CXXBasePaths Paths;
+  CXXBasePath *Path = FindBestPath(S, EC, Entity, FinalAccess, Paths);
+  if (!Path)
+    return AR_dependent;
+
+  assert(Path->Access <= UnprivilegedAccess &&
+         "access along best path worse than direct?");
+  if (Path->Access == AS_public)
+    return AR_accessible;
+  return AR_inaccessible;
+}
+
+static void DelayDependentAccess(Sema &S,
+                                 const EffectiveContext &EC,
+                                 SourceLocation Loc,
+                                 const AccessTarget &Entity) {
+  assert(EC.isDependent() && "delaying non-dependent access");
+  DeclContext *DC = EC.getInnerContext();
+  assert(DC->isDependentContext() && "delaying non-dependent access");
+  DependentDiagnostic::Create(S.Context, DC, DependentDiagnostic::Access,
+                              Loc,
+                              Entity.isMemberAccess(),
+                              Entity.getAccess(),
+                              Entity.getTargetDecl(),
+                              Entity.getNamingClass(),
+                              Entity.getBaseObjectType(),
+                              Entity.getDiag());
+}
+
+/// Checks access to an entity from the given effective context.
+static AccessResult CheckEffectiveAccess(Sema &S,
+                                         const EffectiveContext &EC,
+                                         SourceLocation Loc,
+                                         AccessTarget &Entity) {
+  assert(Entity.getAccess() != AS_public && "called for public access!");
+
+  if (S.getLangOpts().MicrosoftMode &&
+      IsMicrosoftUsingDeclarationAccessBug(S, Loc, Entity))
+    return AR_accessible;
+
+  switch (IsAccessible(S, EC, Entity)) {
+  case AR_dependent:
+    DelayDependentAccess(S, EC, Loc, Entity);
+    return AR_dependent;
+
+  case AR_inaccessible:
+    if (!Entity.isQuiet())
+      DiagnoseBadAccess(S, Loc, EC, Entity);
+    return AR_inaccessible;
+
+  case AR_accessible:
+    return AR_accessible;
+  }
+
+  // silence unnecessary warning
+  llvm_unreachable("invalid access result");
+}
+
+static Sema::AccessResult CheckAccess(Sema &S, SourceLocation Loc,
+                                      AccessTarget &Entity) {
+  // If the access path is public, it's accessible everywhere.
+  if (Entity.getAccess() == AS_public)
+    return Sema::AR_accessible;
+
+  if (S.SuppressAccessChecking)
+    return Sema::AR_accessible;
+
+  // If we're currently parsing a declaration, we may need to delay
+  // access control checking, because our effective context might be
+  // different based on what the declaration comes out as.
+  //
+  // For example, we might be parsing a declaration with a scope
+  // specifier, like this:
+  //   A::private_type A::foo() { ... }
+  //
+  // Or we might be parsing something that will turn out to be a friend:
+  //   void foo(A::private_type);
+  //   void B::foo(A::private_type);
+  if (S.DelayedDiagnostics.shouldDelayDiagnostics()) {
+    S.DelayedDiagnostics.add(DelayedDiagnostic::makeAccess(Loc, Entity));
+    return Sema::AR_delayed;
+  }
+
+  EffectiveContext EC(S.CurContext);
+  switch (CheckEffectiveAccess(S, EC, Loc, Entity)) {
+  case AR_accessible: return Sema::AR_accessible;
+  case AR_inaccessible: return Sema::AR_inaccessible;
+  case AR_dependent: return Sema::AR_dependent;
+  }
+  llvm_unreachable("falling off end");
+}
+
+void Sema::HandleDelayedAccessCheck(DelayedDiagnostic &DD, Decl *decl) {
+  // Access control for names used in the declarations of functions
+  // and function templates should normally be evaluated in the context
+  // of the declaration, just in case it's a friend of something.
+  // However, this does not apply to local extern declarations.
+
+  DeclContext *DC = decl->getDeclContext();
+  if (FunctionDecl *fn = dyn_cast<FunctionDecl>(decl)) {
+    if (!DC->isFunctionOrMethod()) DC = fn;
+  } else if (FunctionTemplateDecl *fnt = dyn_cast<FunctionTemplateDecl>(decl)) {
+    // Never a local declaration.
+    DC = fnt->getTemplatedDecl();
+  }
+
+  EffectiveContext EC(DC);
+
+  AccessTarget Target(DD.getAccessData());
+
+  if (CheckEffectiveAccess(*this, EC, DD.Loc, Target) == ::AR_inaccessible)
+    DD.Triggered = true;
+}
+
+void Sema::HandleDependentAccessCheck(const DependentDiagnostic &DD,
+                        const MultiLevelTemplateArgumentList &TemplateArgs) {
+  SourceLocation Loc = DD.getAccessLoc();
+  AccessSpecifier Access = DD.getAccess();
+
+  Decl *NamingD = FindInstantiatedDecl(Loc, DD.getAccessNamingClass(),
+                                       TemplateArgs);
+  if (!NamingD) return;
+  Decl *TargetD = FindInstantiatedDecl(Loc, DD.getAccessTarget(),
+                                       TemplateArgs);
+  if (!TargetD) return;
+
+  if (DD.isAccessToMember()) {
+    CXXRecordDecl *NamingClass = cast<CXXRecordDecl>(NamingD);
+    NamedDecl *TargetDecl = cast<NamedDecl>(TargetD);
+    QualType BaseObjectType = DD.getAccessBaseObjectType();
+    if (!BaseObjectType.isNull()) {
+      BaseObjectType = SubstType(BaseObjectType, TemplateArgs, Loc,
+                                 DeclarationName());
+      if (BaseObjectType.isNull()) return;
+    }
+
+    AccessTarget Entity(Context,
+                        AccessTarget::Member,
+                        NamingClass,
+                        DeclAccessPair::make(TargetDecl, Access),
+                        BaseObjectType);
+    Entity.setDiag(DD.getDiagnostic());
+    CheckAccess(*this, Loc, Entity);
+  } else {
+    AccessTarget Entity(Context,
+                        AccessTarget::Base,
+                        cast<CXXRecordDecl>(TargetD),
+                        cast<CXXRecordDecl>(NamingD),
+                        Access);
+    Entity.setDiag(DD.getDiagnostic());
+    CheckAccess(*this, Loc, Entity);
+  }
+}
+
+Sema::AccessResult Sema::CheckUnresolvedLookupAccess(UnresolvedLookupExpr *E,
+                                                     DeclAccessPair Found) {
+  if (!getLangOpts().AccessControl ||
+      !E->getNamingClass() ||
+      Found.getAccess() == AS_public)
+    return AR_accessible;
+
+  AccessTarget Entity(Context, AccessTarget::Member, E->getNamingClass(), 
+                      Found, QualType());
+  Entity.setDiag(diag::err_access) << E->getSourceRange();
+
+  return CheckAccess(*this, E->getNameLoc(), Entity);
+}
+
+/// Perform access-control checking on a previously-unresolved member
+/// access which has now been resolved to a member.
+Sema::AccessResult Sema::CheckUnresolvedMemberAccess(UnresolvedMemberExpr *E,
+                                                     DeclAccessPair Found) {
+  if (!getLangOpts().AccessControl ||
+      Found.getAccess() == AS_public)
+    return AR_accessible;
+
+  QualType BaseType = E->getBaseType();
+  if (E->isArrow())
+    BaseType = BaseType->getAs<PointerType>()->getPointeeType();
+
+  AccessTarget Entity(Context, AccessTarget::Member, E->getNamingClass(),
+                      Found, BaseType);
+  Entity.setDiag(diag::err_access) << E->getSourceRange();
+
+  return CheckAccess(*this, E->getMemberLoc(), Entity);
+}
+
+/// Is the given special member function accessible for the purposes of
+/// deciding whether to define a special member function as deleted?
+bool Sema::isSpecialMemberAccessibleForDeletion(CXXMethodDecl *decl,
+                                                AccessSpecifier access,
+                                                QualType objectType) {
+  // Fast path.
+  if (access == AS_public || !getLangOpts().AccessControl) return true;
+
+  AccessTarget entity(Context, AccessTarget::Member, decl->getParent(),
+                      DeclAccessPair::make(decl, access), objectType);
+
+  // Suppress diagnostics.
+  entity.setDiag(PDiag());
+
+  switch (CheckAccess(*this, SourceLocation(), entity)) {
+  case AR_accessible: return true;
+  case AR_inaccessible: return false;
+  case AR_dependent: llvm_unreachable("dependent for =delete computation");
+  case AR_delayed: llvm_unreachable("cannot delay =delete computation");
+  }
+  llvm_unreachable("bad access result");
+}
+
+Sema::AccessResult Sema::CheckDestructorAccess(SourceLocation Loc,
+                                               CXXDestructorDecl *Dtor,
+                                               const PartialDiagnostic &PDiag,
+                                               QualType ObjectTy) {
+  if (!getLangOpts().AccessControl)
+    return AR_accessible;
+
+  // There's never a path involved when checking implicit destructor access.
+  AccessSpecifier Access = Dtor->getAccess();
+  if (Access == AS_public)
+    return AR_accessible;
+
+  CXXRecordDecl *NamingClass = Dtor->getParent();
+  if (ObjectTy.isNull()) ObjectTy = Context.getTypeDeclType(NamingClass);
+
+  AccessTarget Entity(Context, AccessTarget::Member, NamingClass,
+                      DeclAccessPair::make(Dtor, Access),
+                      ObjectTy);
+  Entity.setDiag(PDiag); // TODO: avoid copy
+
+  return CheckAccess(*this, Loc, Entity);
+}
+
+/// Checks access to a constructor.
+Sema::AccessResult Sema::CheckConstructorAccess(SourceLocation UseLoc,
+                                                CXXConstructorDecl *Constructor,
+                                                const InitializedEntity &Entity,
+                                                AccessSpecifier Access,
+                                                bool IsCopyBindingRefToTemp) {
+  if (!getLangOpts().AccessControl || Access == AS_public)
+    return AR_accessible;
+
+  PartialDiagnostic PD(PDiag());
+  switch (Entity.getKind()) {
+  default:
+    PD = PDiag(IsCopyBindingRefToTemp
+                 ? diag::ext_rvalue_to_reference_access_ctor
+                 : diag::err_access_ctor);
+
+    break;
+
+  case InitializedEntity::EK_Base:
+    PD = PDiag(diag::err_access_base_ctor);
+    PD << Entity.isInheritedVirtualBase()
+       << Entity.getBaseSpecifier()->getType() << getSpecialMember(Constructor);
+    break;
+
+  case InitializedEntity::EK_Member: {
+    const FieldDecl *Field = cast<FieldDecl>(Entity.getDecl());
+    PD = PDiag(diag::err_access_field_ctor);
+    PD << Field->getType() << getSpecialMember(Constructor);
+    break;
+  }
+
+  case InitializedEntity::EK_LambdaCapture: {
+    const VarDecl *Var = Entity.getCapturedVar();
+    PD = PDiag(diag::err_access_lambda_capture);
+    PD << Var->getName() << Entity.getType() << getSpecialMember(Constructor);
+    break;
+  }
+
+  }
+
+  return CheckConstructorAccess(UseLoc, Constructor, Entity, Access, PD);
+}
+
+/// Checks access to a constructor.
+Sema::AccessResult Sema::CheckConstructorAccess(SourceLocation UseLoc,
+                                                CXXConstructorDecl *Constructor,
+                                                const InitializedEntity &Entity,
+                                                AccessSpecifier Access,
+                                                const PartialDiagnostic &PD) {
+  if (!getLangOpts().AccessControl ||
+      Access == AS_public)
+    return AR_accessible;
+
+  CXXRecordDecl *NamingClass = Constructor->getParent();
+
+  // Initializing a base sub-object is an instance method call on an
+  // object of the derived class.  Otherwise, we have an instance method
+  // call on an object of the constructed type.
+  CXXRecordDecl *ObjectClass;
+  if (Entity.getKind() == InitializedEntity::EK_Base) {
+    ObjectClass = cast<CXXConstructorDecl>(CurContext)->getParent();
+  } else {
+    ObjectClass = NamingClass;
+  }
+
+  AccessTarget AccessEntity(Context, AccessTarget::Member, NamingClass,
+                            DeclAccessPair::make(Constructor, Access),
+                            Context.getTypeDeclType(ObjectClass));
+  AccessEntity.setDiag(PD);
+
+  return CheckAccess(*this, UseLoc, AccessEntity);
+} 
+
+/// Checks direct (i.e. non-inherited) access to an arbitrary class
+/// member.
+Sema::AccessResult Sema::CheckDirectMemberAccess(SourceLocation UseLoc,
+                                                 NamedDecl *Target,
+                                           const PartialDiagnostic &Diag) {
+  AccessSpecifier Access = Target->getAccess();
+  if (!getLangOpts().AccessControl ||
+      Access == AS_public)
+    return AR_accessible;
+
+  CXXRecordDecl *NamingClass = cast<CXXRecordDecl>(Target->getDeclContext());
+  AccessTarget Entity(Context, AccessTarget::Member, NamingClass,
+                      DeclAccessPair::make(Target, Access),
+                      QualType());
+  Entity.setDiag(Diag);
+  return CheckAccess(*this, UseLoc, Entity);
+}
+                                           
+
+/// Checks access to an overloaded operator new or delete.
+Sema::AccessResult Sema::CheckAllocationAccess(SourceLocation OpLoc,
+                                               SourceRange PlacementRange,
+                                               CXXRecordDecl *NamingClass,
+                                               DeclAccessPair Found,
+                                               bool Diagnose) {
+  if (!getLangOpts().AccessControl ||
+      !NamingClass ||
+      Found.getAccess() == AS_public)
+    return AR_accessible;
+
+  AccessTarget Entity(Context, AccessTarget::Member, NamingClass, Found,
+                      QualType());
+  if (Diagnose)
+    Entity.setDiag(diag::err_access)
+      << PlacementRange;
+
+  return CheckAccess(*this, OpLoc, Entity);
+}
+
+/// Checks access to an overloaded member operator, including
+/// conversion operators.
+Sema::AccessResult Sema::CheckMemberOperatorAccess(SourceLocation OpLoc,
+                                                   Expr *ObjectExpr,
+                                                   Expr *ArgExpr,
+                                                   DeclAccessPair Found) {
+  if (!getLangOpts().AccessControl ||
+      Found.getAccess() == AS_public)
+    return AR_accessible;
+
+  const RecordType *RT = ObjectExpr->getType()->castAs<RecordType>();
+  CXXRecordDecl *NamingClass = cast<CXXRecordDecl>(RT->getDecl());
+
+  AccessTarget Entity(Context, AccessTarget::Member, NamingClass, Found,
+                      ObjectExpr->getType());
+  Entity.setDiag(diag::err_access)
+    << ObjectExpr->getSourceRange()
+    << (ArgExpr ? ArgExpr->getSourceRange() : SourceRange());
+
+  return CheckAccess(*this, OpLoc, Entity);
+}
+
+Sema::AccessResult Sema::CheckAddressOfMemberAccess(Expr *OvlExpr,
+                                                    DeclAccessPair Found) {
+  if (!getLangOpts().AccessControl ||
+      Found.getAccess() == AS_none ||
+      Found.getAccess() == AS_public)
+    return AR_accessible;
+
+  OverloadExpr *Ovl = OverloadExpr::find(OvlExpr).Expression;
+  CXXRecordDecl *NamingClass = Ovl->getNamingClass();
+
+  AccessTarget Entity(Context, AccessTarget::Member, NamingClass, Found,
+                      /*no instance context*/ QualType());
+  Entity.setDiag(diag::err_access)
+    << Ovl->getSourceRange();
+
+  return CheckAccess(*this, Ovl->getNameLoc(), Entity);
+}
+
+/// Checks access for a hierarchy conversion.
+///
+/// \param IsBaseToDerived whether this is a base-to-derived conversion (true)
+///     or a derived-to-base conversion (false)
+/// \param ForceCheck true if this check should be performed even if access
+///     control is disabled;  some things rely on this for semantics
+/// \param ForceUnprivileged true if this check should proceed as if the
+///     context had no special privileges
+/// \param ADK controls the kind of diagnostics that are used
+Sema::AccessResult Sema::CheckBaseClassAccess(SourceLocation AccessLoc,
+                                              QualType Base,
+                                              QualType Derived,
+                                              const CXXBasePath &Path,
+                                              unsigned DiagID,
+                                              bool ForceCheck,
+                                              bool ForceUnprivileged) {
+  if (!ForceCheck && !getLangOpts().AccessControl)
+    return AR_accessible;
+
+  if (Path.Access == AS_public)
+    return AR_accessible;
+
+  CXXRecordDecl *BaseD, *DerivedD;
+  BaseD = cast<CXXRecordDecl>(Base->getAs<RecordType>()->getDecl());
+  DerivedD = cast<CXXRecordDecl>(Derived->getAs<RecordType>()->getDecl());
+
+  AccessTarget Entity(Context, AccessTarget::Base, BaseD, DerivedD, 
+                      Path.Access);
+  if (DiagID)
+    Entity.setDiag(DiagID) << Derived << Base;
+
+  if (ForceUnprivileged) {
+    switch (CheckEffectiveAccess(*this, EffectiveContext(),
+                                 AccessLoc, Entity)) {
+    case ::AR_accessible: return Sema::AR_accessible;
+    case ::AR_inaccessible: return Sema::AR_inaccessible;
+    case ::AR_dependent: return Sema::AR_dependent;
+    }
+    llvm_unreachable("unexpected result from CheckEffectiveAccess");
+  }
+  return CheckAccess(*this, AccessLoc, Entity);
+}
+
+/// Checks access to all the declarations in the given result set.
+void Sema::CheckLookupAccess(const LookupResult &R) {
+  assert(getLangOpts().AccessControl
+         && "performing access check without access control");
+  assert(R.getNamingClass() && "performing access check without naming class");
+
+  for (LookupResult::iterator I = R.begin(), E = R.end(); I != E; ++I) {
+    if (I.getAccess() != AS_public) {
+      AccessTarget Entity(Context, AccessedEntity::Member,
+                          R.getNamingClass(), I.getPair(),
+                          R.getBaseObjectType());
+      Entity.setDiag(diag::err_access);
+      CheckAccess(*this, R.getNameLoc(), Entity);
+    }
+  }
+}
+
+/// Checks access to Decl from the given class. The check will take access
+/// specifiers into account, but no member access expressions and such.
+///
+/// \param Decl the declaration to check if it can be accessed
+/// \param Class the class/context from which to start the search
+/// \return true if the Decl is accessible from the Class, false otherwise.
+bool Sema::IsSimplyAccessible(NamedDecl *Decl, DeclContext *Ctx) {
+  if (CXXRecordDecl *Class = dyn_cast<CXXRecordDecl>(Ctx)) {
+    if (!Decl->isCXXClassMember())
+      return true;
+
+    QualType qType = Class->getTypeForDecl()->getCanonicalTypeInternal();
+    AccessTarget Entity(Context, AccessedEntity::Member, Class,
+                        DeclAccessPair::make(Decl, Decl->getAccess()),
+                        qType);
+    if (Entity.getAccess() == AS_public)
+      return true;
+
+    EffectiveContext EC(CurContext);
+    return ::IsAccessible(*this, EC, Entity) != ::AR_inaccessible;
+  }
+  
+  if (ObjCIvarDecl *Ivar = dyn_cast<ObjCIvarDecl>(Decl)) {
+    // @public and @package ivars are always accessible.
+    if (Ivar->getCanonicalAccessControl() == ObjCIvarDecl::Public ||
+        Ivar->getCanonicalAccessControl() == ObjCIvarDecl::Package)
+      return true;
+    
+    
+    
+    // If we are inside a class or category implementation, determine the
+    // interface we're in.
+    ObjCInterfaceDecl *ClassOfMethodDecl = 0;
+    if (ObjCMethodDecl *MD = getCurMethodDecl())
+      ClassOfMethodDecl =  MD->getClassInterface();
+    else if (FunctionDecl *FD = getCurFunctionDecl()) {
+      if (ObjCImplDecl *Impl 
+            = dyn_cast<ObjCImplDecl>(FD->getLexicalDeclContext())) {
+        if (ObjCImplementationDecl *IMPD
+              = dyn_cast<ObjCImplementationDecl>(Impl))
+          ClassOfMethodDecl = IMPD->getClassInterface();
+        else if (ObjCCategoryImplDecl* CatImplClass
+                   = dyn_cast<ObjCCategoryImplDecl>(Impl))
+          ClassOfMethodDecl = CatImplClass->getClassInterface();
+      }
+    }
+    
+    // If we're not in an interface, this ivar is inaccessible.
+    if (!ClassOfMethodDecl)
+      return false;
+    
+    // If we're inside the same interface that owns the ivar, we're fine.
+    if (declaresSameEntity(ClassOfMethodDecl, Ivar->getContainingInterface()))
+      return true;
+    
+    // If the ivar is private, it's inaccessible.
+    if (Ivar->getCanonicalAccessControl() == ObjCIvarDecl::Private)
+      return false;
+    
+    return Ivar->getContainingInterface()->isSuperClassOf(ClassOfMethodDecl);
+  }
+  
+  return true;
+}
+
+void Sema::ActOnStartSuppressingAccessChecks() {
+  assert(!SuppressAccessChecking &&
+         "Tried to start access check suppression when already started.");
+  SuppressAccessChecking = true;
+}
+
+void Sema::ActOnStopSuppressingAccessChecks() {
+  assert(SuppressAccessChecking &&
+         "Tried to stop access check suprression when already stopped.");
+  SuppressAccessChecking = false;
+}