path: root/lib/Sema/SemaAccess.cpp

//===---- 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 "Sema.h"
#include "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/DependentDiagnostic.h"
#include "clang/AST/ExprCXX.h"

using namespace clang;

/// 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;
}

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);
        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 llvm::SmallVectorImpl<CXXRecordDecl*>::const_iterator record_iterator;

  DeclContext *Inner;
  llvm::SmallVector<FunctionDecl*, 4> Functions;
  llvm::SmallVector<CXXRecordDecl*, 4> Records;
  bool Dependent;
};
}

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;
}

static bool MightInstantiateTo(Sema &S, DeclContext *Context,
                               DeclContext *Friend)