SemaDeclCXX.cpp

//===------ SemaDeclCXX.cpp - Semantic Analysis for C++ Declarations ------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
//  This file implements semantic analysis for C++ declarations.
//
//===----------------------------------------------------------------------===//

#include "Sema.h"
#include "SemaInherit.h"
#include "clang/AST/ASTConsumer.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/TypeOrdering.h"
#include "clang/AST/StmtVisitor.h"
#include "clang/Lex/Preprocessor.h"
#include "clang/Basic/Diagnostic.h"
#include "clang/Parse/DeclSpec.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/Support/Compiler.h"
#include <algorithm> // for std::equal
#include <map>

using namespace clang;

//===----------------------------------------------------------------------===//
// CheckDefaultArgumentVisitor
//===----------------------------------------------------------------------===//

namespace {
  /// CheckDefaultArgumentVisitor - C++ [dcl.fct.default] Traverses
  /// the default argument of a parameter to determine whether it
  /// contains any ill-formed subexpressions. For example, this will
  /// diagnose the use of local variables or parameters within the
  /// default argument expression.
  class VISIBILITY_HIDDEN CheckDefaultArgumentVisitor 
    : public StmtVisitor<CheckDefaultArgumentVisitor, bool> {
    Expr *DefaultArg;
    Sema *S;

  public:
    CheckDefaultArgumentVisitor(Expr *defarg, Sema *s) 
      : DefaultArg(defarg), S(s) {}

    bool VisitExpr(Expr *Node);
    bool VisitDeclRefExpr(DeclRefExpr *DRE);
    bool VisitCXXThisExpr(CXXThisExpr *ThisE);
  };

  /// VisitExpr - Visit all of the children of this expression.
  bool CheckDefaultArgumentVisitor::VisitExpr(Expr *Node) {
    bool IsInvalid = false;
    for (Stmt::child_iterator I = Node->child_begin(), 
         E = Node->child_end(); I != E; ++I)
      IsInvalid |= Visit(*I);
    return IsInvalid;
  }

  /// VisitDeclRefExpr - Visit a reference to a declaration, to
  /// determine whether this declaration can be used in the default
  /// argument expression.
  bool CheckDefaultArgumentVisitor::VisitDeclRefExpr(DeclRefExpr *DRE) {
    NamedDecl *Decl = DRE->getDecl();
    if (ParmVarDecl *Param = dyn_cast<ParmVarDecl>(Decl)) {
      // C++ [dcl.fct.default]p9
      //   Default arguments are evaluated each time the function is
      //   called. The order of evaluation of function arguments is
      //   unspecified. Consequently, parameters of a function shall not
      //   be used in default argument expressions, even if they are not
      //   evaluated. Parameters of a function declared before a default
      //   argument expression are in scope and can hide namespace and
      //   class member names.
      return S->Diag(DRE->getSourceRange().getBegin(), 
                     diag::err_param_default_argument_references_param,
                     Param->getName(), DefaultArg->getSourceRange());
    } else if (VarDecl *VDecl = dyn_cast<VarDecl>(Decl)) {
      // C++ [dcl.fct.default]p7
      //   Local variables shall not be used in default argument
      //   expressions.
      if (VDecl->isBlockVarDecl())
        return S->Diag(DRE->getSourceRange().getBegin(), 
                       diag::err_param_default_argument_references_local,
                       VDecl->getName(), DefaultArg->getSourceRange());
    }

    return false;
  }

  /// VisitCXXThisExpr - Visit a C++ "this" expression.
  bool CheckDefaultArgumentVisitor::VisitCXXThisExpr(CXXThisExpr *ThisE) {
    // C++ [dcl.fct.default]p8:
    //   The keyword this shall not be used in a default argument of a
    //   member function.
    return S->Diag(ThisE->getSourceRange().getBegin(),
                   diag::err_param_default_argument_references_this,
                   ThisE->getSourceRange());
  }
}

/// ActOnParamDefaultArgument - Check whether the default argument
/// provided for a function parameter is well-formed. If so, attach it
/// to the parameter declaration.
void
Sema::ActOnParamDefaultArgument(DeclTy *param, SourceLocation EqualLoc, 
                                ExprTy *defarg) {
  ParmVarDecl *Param = (ParmVarDecl *)param;
  llvm::OwningPtr<Expr> DefaultArg((Expr *)defarg);
  QualType ParamType = Param->getType();

  // Default arguments are only permitted in C++
  if (!getLangOptions().CPlusPlus) {
    Diag(EqualLoc, diag::err_param_default_argument, 
         DefaultArg->getSourceRange());
    return;
  }

  // C++ [dcl.fct.default]p5
  //   A default argument expression is implicitly converted (clause
  //   4) to the parameter type. The default argument expression has
  //   the same semantic constraints as the initializer expression in
  //   a declaration of a variable of the parameter type, using the
  //   copy-initialization semantics (8.5).
  Expr *DefaultArgPtr = DefaultArg.get();
  bool DefaultInitFailed = PerformCopyInitialization(DefaultArgPtr, ParamType,
                                                     "in default argument");
  if (DefaultArgPtr != DefaultArg.get()) {
    DefaultArg.take();
    DefaultArg.reset(DefaultArgPtr);
  }
  if (DefaultInitFailed) {
    return;
  }

  // Check that the default argument is well-formed
  CheckDefaultArgumentVisitor DefaultArgChecker(DefaultArg.get(), this);
  if (DefaultArgChecker.Visit(DefaultArg.get()))
    return;

  // Okay: add the default argument to the parameter
  Param->setDefaultArg(DefaultArg.take());
}

/// CheckExtraCXXDefaultArguments - Check for any extra default
/// arguments in the declarator, which is not a function declaration
/// or definition and therefore is not permitted to have default
/// arguments. This routine should be invoked for every declarator
/// that is not a function declaration or definition.
void Sema::CheckExtraCXXDefaultArguments(Declarator &D) {
  // C++ [dcl.fct.default]p3
  //   A default argument expression shall be specified only in the
  //   parameter-declaration-clause of a function declaration or in a
  //   template-parameter (14.1). It shall not be specified for a
  //   parameter pack. If it is specified in a
  //   parameter-declaration-clause, it shall not occur within a
  //   declarator or abstract-declarator of a parameter-declaration.
  for (unsigned i = 0; i < D.getNumTypeObjects(); ++i) {
    DeclaratorChunk &chunk = D.getTypeObject(i);
    if (chunk.Kind == DeclaratorChunk::Function) {
      for (unsigned argIdx = 0; argIdx < chunk.Fun.NumArgs; ++argIdx) {
        ParmVarDecl *Param = (ParmVarDecl *)chunk.Fun.ArgInfo[argIdx].Param;
        if (Param->getDefaultArg()) {
          Diag(Param->getLocation(), diag::err_param_default_argument_nonfunc,
               Param->getDefaultArg()->getSourceRange());
          Param->setDefaultArg(0);
        }
      }
    }
  }
}

// MergeCXXFunctionDecl - Merge two declarations of the same C++
// function, once we already know that they have the same
// type. Subroutine of MergeFunctionDecl.
FunctionDecl * 
Sema::MergeCXXFunctionDecl(FunctionDecl *New, FunctionDecl *Old) {
  // C++ [dcl.fct.default]p4:
  //
  //   For non-template functions, default arguments can be added in
  //   later declarations of a function in the same
  //   scope. Declarations in different scopes have completely
  //   distinct sets of default arguments. That is, declarations in
  //   inner scopes do not acquire default arguments from
  //   declarations in outer scopes, and vice versa. In a given
  //   function declaration, all parameters subsequent to a
  //   parameter with a default argument shall have default
  //   arguments supplied in this or previous declarations. A
  //   default argument shall not be redefined by a later
  //   declaration (not even to the same value).
  for (unsigned p = 0, NumParams = Old->getNumParams(); p < NumParams; ++p) {
    ParmVarDecl *OldParam = Old->getParamDecl(p);
    ParmVarDecl *NewParam = New->getParamDecl(p);

    if(OldParam->getDefaultArg() && NewParam->getDefaultArg()) {
      Diag(NewParam->getLocation(), 
           diag::err_param_default_argument_redefinition,
           NewParam->getDefaultArg()->getSourceRange());
      Diag(OldParam->getLocation(), diag::err_previous_definition);
    } else if (OldParam->getDefaultArg()) {
      // Merge the old default argument into the new parameter
      NewParam->setDefaultArg(OldParam->getDefaultArg());
    }
  }

  return New;  
}

/// CheckCXXDefaultArguments - Verify that the default arguments for a
/// function declaration are well-formed according to C++
/// [dcl.fct.default].
void Sema::CheckCXXDefaultArguments(FunctionDecl *FD) {
  unsigned NumParams = FD->getNumParams();
  unsigned p;

  // Find first parameter with a default argument
  for (p = 0; p < NumParams; ++p) {
    ParmVarDecl *Param = FD->getParamDecl(p);
    if (Param->getDefaultArg())
      break;
  }

  // C++ [dcl.fct.default]p4:
  //   In a given function declaration, all parameters
  //   subsequent to a parameter with a default argument shall
  //   have default arguments supplied in this or previous
  //   declarations. A default argument shall not be redefined
  //   by a later declaration (not even to the same value).
  unsigned LastMissingDefaultArg = 0;
  for(; p < NumParams; ++p) {
    ParmVarDecl *Param = FD->getParamDecl(p);
    if (!Param->getDefaultArg()) {
      if (Param->getIdentifier())
        Diag(Param->getLocation(), 
             diag::err_param_default_argument_missing_name,
             Param->getIdentifier()->getName());
      else
        Diag(Param->getLocation(), 
             diag::err_param_default_argument_missing);
    
      LastMissingDefaultArg = p;
    }
  }

  if (LastMissingDefaultArg > 0) {
    // Some default arguments were missing. Clear out all of the
    // default arguments up to (and including) the last missing
    // default argument, so that we leave the function parameters
    // in a semantically valid state.
    for (p = 0; p <= LastMissingDefaultArg; ++p) {
      ParmVarDecl *Param = FD->getParamDecl(p);
      if (Param->getDefaultArg()) {
        delete Param->getDefaultArg();
        Param->setDefaultArg(0);
      }
    }
  }
}

/// isCurrentClassName - Determine whether the identifier II is the
/// name of the class type currently being defined. In the case of
/// nested classes, this will only return true if II is the name of
/// the innermost class.
bool Sema::isCurrentClassName(const IdentifierInfo &II, Scope *,
                              const CXXScopeSpec *SS) {
  CXXRecordDecl *CurDecl;
  if (SS) {
    DeclContext *DC = static_cast<DeclContext*>(SS->getScopeRep());
    CurDecl = dyn_cast_or_null<CXXRecordDecl>(DC);
  } else
    CurDecl = dyn_cast_or_null<CXXRecordDecl>(CurContext);

  if (CurDecl)
    return &II == CurDecl->getIdentifier();
  else
    return false;
}

/// ActOnBaseSpecifier - Parsed a base specifier. A base specifier is
/// one entry in the base class list of a class specifier, for
/// example: 
///    class foo : public bar, virtual private baz { 
/// 'public bar' and 'virtual private baz' are each base-specifiers.
Sema::BaseResult 
Sema::ActOnBaseSpecifier(DeclTy *classdecl, SourceRange SpecifierRange,
                         bool Virtual, AccessSpecifier Access,
                         TypeTy *basetype, SourceLocation BaseLoc) {
  RecordDecl *Decl = (RecordDecl*)classdecl;
  QualType BaseType = Context.getTypeDeclType((TypeDecl*)basetype);

  // Base specifiers must be record types.
  if (!BaseType->isRecordType()) {
    Diag(BaseLoc, diag::err_base_must_be_class, SpecifierRange);
    return true;
  }

  // C++ [class.union]p1:
  //   A union shall not be used as a base class.
  if (BaseType->isUnionType()) {
    Diag(BaseLoc, diag::err_union_as_base_class, SpecifierRange);
    return true;
  }

  // C++ [class.union]p1:
  //   A union shall not have base classes.
  if (Decl->isUnion()) {
    Diag(Decl->getLocation(), diag::err_base_clause_on_union,
         SpecifierRange);
    return true;
  }

  // C++ [class.derived]p2:
  //   The class-name in a base-specifier shall not be an incompletely
  //   defined class.
  if (BaseType->isIncompleteType()) {
    Diag(BaseLoc, diag::err_incomplete_base_class, SpecifierRange);
    return true;
  }

  // If the base class is polymorphic, the new one is, too.
  RecordDecl *BaseDecl = BaseType->getAsRecordType()->getDecl();
  assert(BaseDecl && "Record type has no declaration");
  BaseDecl = BaseDecl->getDefinition(Context);
  assert(BaseDecl && "Base type is not incomplete, but has no definition");
  if (cast<CXXRecordDecl>(BaseDecl)->isPolymorphic()) {
    cast<CXXRecordDecl>(Decl)->setPolymorphic(true);
  }

  // Create the base specifier.
  return new CXXBaseSpecifier(SpecifierRange, Virtual, 
                              BaseType->isClassType(), Access, BaseType);
}

/// ActOnBaseSpecifiers - Attach the given base specifiers to the
/// class, after checking whether there are any duplicate base
/// classes.
void Sema::ActOnBaseSpecifiers(DeclTy *ClassDecl, BaseTy **Bases, 
                               unsigned NumBases) {
  if (NumBases == 0)
    return;

  // Used to keep track of which base types we have already seen, so
  // that we can properly diagnose redundant direct base types. Note
  // that the key is always the unqualified canonical type of the base
  // class.
  std::map<QualType, CXXBaseSpecifier*, QualTypeOrdering> KnownBaseTypes;

  // Copy non-redundant base specifiers into permanent storage.
  CXXBaseSpecifier **BaseSpecs = (CXXBaseSpecifier **)Bases;
  unsigned NumGoodBases = 0;
  for (unsigned idx = 0; idx < NumBases; ++idx) {
    QualType NewBaseType 
      = Context.getCanonicalType(BaseSpecs[idx]->getType());
    NewBaseType = NewBaseType.getUnqualifiedType();

    if (KnownBaseTypes[NewBaseType]) {
      // C++ [class.mi]p3:
      //   A class shall not be specified as a direct base class of a
      //   derived class more than once.
      Diag(BaseSpecs[idx]->getSourceRange().getBegin(),
           diag::err_duplicate_base_class, 
           KnownBaseTypes[NewBaseType]->getType().getAsString(),
           BaseSpecs[idx]->getSourceRange());

      // Delete the duplicate base class specifier; we're going to
      // overwrite its pointer later.
      delete BaseSpecs[idx];
    } else {
      // Okay, add this new base class.
      KnownBaseTypes[NewBaseType] = BaseSpecs[idx];
      BaseSpecs[NumGoodBases++] = BaseSpecs[idx];
    }
  }

  // Attach the remaining base class specifiers to the derived class.
  CXXRecordDecl *Decl = (CXXRecordDecl*)ClassDecl;
  Decl->setBases(BaseSpecs, NumGoodBases);

  // Delete the remaining (good) base class specifiers, since their
  // data has been copied into the CXXRecordDecl.
  for (unsigned idx = 0; idx < NumGoodBases; ++idx)
    delete BaseSpecs[idx];
}

//===----------------------------------------------------------------------===//
// C++ class member Handling
//===----------------------------------------------------------------------===//

/// ActOnStartCXXClassDef - This is called at the start of a class/struct/union
/// definition, when on C++.
void Sema::ActOnStartCXXClassDef(Scope *S, DeclTy *D, SourceLocation LBrace) {
  CXXRecordDecl *Dcl = cast<CXXRecordDecl>(static_cast<Decl *>(D));
  PushDeclContext(Dcl);
  FieldCollector->StartClass();

  if (Dcl->getIdentifier()) {
    // C++ [class]p2: 
    //   [...] The class-name is also inserted into the scope of the
    //   class itself; this is known as the injected-class-name. For
    //   purposes of access checking, the injected-class-name is treated
    //   as if it were a public member name.
    PushOnScopeChains(Dcl, S);
  }
}

/// ActOnCXXMemberDeclarator - This is invoked when a C++ class member
/// declarator is parsed. 'AS' is the access specifier, 'BW' specifies the
/// bitfield width if there is one and 'InitExpr' specifies the initializer if
/// any. 'LastInGroup' is non-null for cases where one declspec has multiple
/// declarators on it.
///
/// NOTE: Because of CXXFieldDecl's inability to be chained like ScopedDecls, if
/// an instance field is declared, a new CXXFieldDecl is created but the method
/// does *not* return it; it returns LastInGroup instead. The other C++ members
/// (which are all ScopedDecls) are returned after appending them to
/// LastInGroup.
Sema::DeclTy *
Sema::ActOnCXXMemberDeclarator(Scope *S, AccessSpecifier AS, Declarator &D,
                               ExprTy *BW, ExprTy *InitExpr,
                               DeclTy *LastInGroup) {
  const DeclSpec &DS = D.getDeclSpec();
  IdentifierInfo *II = D.getIdentifier();
  Expr *BitWidth = static_cast<Expr*>(BW);
  Expr *Init = static_cast<Expr*>(InitExpr);
  SourceLocation Loc = D.getIdentifierLoc();

  bool isFunc = D.isFunctionDeclarator();

  // C++ 9.2p6: A member shall not be declared to have automatic storage
  // duration (auto, register) or with the extern storage-class-specifier.
  // C++ 7.1.1p8: The mutable specifier can be applied only to names of class
  // data members and cannot be applied to names declared const or static,
  // and cannot be applied to reference members.
  switch (DS.getStorageClassSpec()) {
    case DeclSpec::SCS_unspecified:
    case DeclSpec::SCS_typedef:
    case DeclSpec::SCS_static:
      // FALL THROUGH.
      break;
    case DeclSpec::SCS_mutable:
      if (isFunc) {
        if (DS.getStorageClassSpecLoc().isValid())
          Diag(DS.getStorageClassSpecLoc(),
               diag::err_mutable_function);
        else
          Diag(DS.getThreadSpecLoc(),
               diag::err_mutable_function);
        D.getMutableDeclSpec().ClearStorageClassSpecs();
      } else {
        QualType T = GetTypeForDeclarator(D, S);
        diag::kind err = static_cast<diag::kind>(0);
        if (T->isReferenceType())
          err = diag::err_mutable_reference;
        else if (T.isConstQualified())
          err = diag::err_mutable_const;
        if (err != 0) {
          if (DS.getStorageClassSpecLoc().isValid())
            Diag(DS.getStorageClassSpecLoc(), err);
          else
            Diag(DS.getThreadSpecLoc(), err);
          D.getMutableDeclSpec().ClearStorageClassSpecs();
        }
      }
      break;
    default:
      if (DS.getStorageClassSpecLoc().isValid())
        Diag(DS.getStorageClassSpecLoc(),
             diag::err_storageclass_invalid_for_member);
      else
        Diag(DS.getThreadSpecLoc(), diag::err_storageclass_invalid_for_member);
      D.getMutableDeclSpec().ClearStorageClassSpecs();
  }

  if (!isFunc &&
      D.getDeclSpec().getTypeSpecType() == DeclSpec::TST_typedef &&
      D.getNumTypeObjects() == 0) {
    // Check also for this case:
    //
    // typedef int f();
    // f a;
    //
    Decl *TD = static_cast<Decl *>(DS.getTypeRep());
    isFunc = Context.getTypeDeclType(cast<TypeDecl>(TD))->isFunctionType();
  }

  bool isInstField = ((DS.getStorageClassSpec() == DeclSpec::SCS_unspecified ||
                       DS.getStorageClassSpec() == DeclSpec::SCS_mutable) &&
                      !isFunc);

  Decl *Member;
  bool InvalidDecl = false;

  if (isInstField)
    Member = static_cast<Decl*>(ActOnField(S, Loc, D, BitWidth));
  else
    Member = static_cast<Decl*>(ActOnDeclarator(S, D, LastInGroup));

  if (!Member) return LastInGroup;

  assert((II || isInstField) && "No identifier for non-field ?");

  // set/getAccess is not part of Decl's interface to avoid bloating it with C++
  // specific methods. Use a wrapper class that can be used with all C++ class
  // member decls.
  CXXClassMemberWrapper(Member).setAccess(AS);

  // C++ [dcl.init.aggr]p1:
  //   An aggregate is an array or a class (clause 9) with [...] no
  //   private or protected non-static data members (clause 11).
  if (isInstField && (AS == AS_private || AS == AS_protected))
    cast<CXXRecordDecl>(CurContext)->setAggregate(false);

  if (DS.isVirtualSpecified()) {
    if (!isFunc || DS.getStorageClassSpec() == DeclSpec::SCS_static) {
      Diag(DS.getVirtualSpecLoc(), diag::err_virtual_non_function);
      InvalidDecl = true;
    } else {
      CXXRecordDecl *CurClass = cast<CXXRecordDecl>(CurContext);
      CurClass->setAggregate(false);
      CurClass->setPolymorphic(true);
    }
  }

  if (BitWidth) {
    // C++ 9.6p2: Only when declaring an unnamed bit-field may the
    // constant-expression be a value equal to zero.
    // FIXME: Check this.

    if (D.isFunctionDeclarator()) {
      // FIXME: Emit diagnostic about only constructors taking base initializers
      // or something similar, when constructor support is in place.
      Diag(Loc, diag::err_not_bitfield_type,
           II->getName(), BitWidth->getSourceRange());
      InvalidDecl = true;

    } else if (isInstField) {
      // C++ 9.6p3: A bit-field shall have integral or enumeration type.
      if (!cast<FieldDecl>(Member)->getType()->isIntegralType()) {
        Diag(Loc, diag::err_not_integral_type_bitfield,
             II->getName(), BitWidth->getSourceRange());
        InvalidDecl = true;
      }

    } else if (isa<FunctionDecl>(Member)) {
      // A function typedef ("typedef int f(); f a;").
      // C++ 9.6p3: A bit-field shall have integral or enumeration type.
      Diag(Loc, diag::err_not_integral_type_bitfield,
           II->getName(), BitWidth->getSourceRange());
      InvalidDecl = true;

    } else if (isa<TypedefDecl>(Member)) {
      // "cannot declare 'A' to be a bit-field type"
      Diag(Loc, diag::err_not_bitfield_type, II->getName(), 
           BitWidth->getSourceRange());
      InvalidDecl = true;

    } else {
      assert(isa<CXXClassVarDecl>(Member) &&
             "Didn't we cover all member kinds?");
      // C++ 9.6p3: A bit-field shall not be a static member.
      // "static member 'A' cannot be a bit-field"
      Diag(Loc, diag::err_static_not_bitfield, II->getName(), 
           BitWidth->getSourceRange());
      InvalidDecl = true;
    }
  }

  if (Init) {
    // C++ 9.2p4: A member-declarator can contain a constant-initializer only
    // if it declares a static member of const integral or const enumeration
    // type.
    if (CXXClassVarDecl *CVD = dyn_cast<CXXClassVarDecl>(Member)) {
      // ...static member of...
      CVD->setInit(Init);
      // ...const integral or const enumeration type.
      if (Context.getCanonicalType(CVD->getType()).isConstQualified() &&
          CVD->getType()->isIntegralType()) {
        // constant-initializer
        if (CheckForConstantInitializer(Init, CVD->getType()))
          InvalidDecl = true;

      } else {
        // not const integral.
        Diag(Loc, diag::err_member_initialization,
             II->getName(), Init->getSourceRange());
        InvalidDecl = true;
      }

    } else {
      // not static member.
      Diag(Loc, diag::err_member_initialization,
           II->getName(), Init->getSourceRange());
      InvalidDecl = true;
    }
  }

  if (InvalidDecl)
    Member->setInvalidDecl();

  if (isInstField) {
    FieldCollector->Add(cast<CXXFieldDecl>(Member));
    return LastInGroup;
  }
  return Member;
}

/// ActOnMemInitializer - Handle a C++ member initializer.
Sema::MemInitResult 
Sema::ActOnMemInitializer(DeclTy *ConstructorD,
                          Scope *S,
                          IdentifierInfo *MemberOrBase,
                          SourceLocation IdLoc,
                          SourceLocation LParenLoc,
                          ExprTy **Args, unsigned NumArgs,
                          SourceLocation *CommaLocs,
                          SourceLocation RParenLoc) {
  CXXConstructorDecl *Constructor 
    = dyn_cast<CXXConstructorDecl>((Decl*)ConstructorD);
  if (!Constructor) {
    // The user wrote a constructor initializer on a function that is
    // not a C++ constructor. Ignore the error for now, because we may
    // have more member initializers coming; we'll diagnose it just
    // once in ActOnMemInitializers.
    return true;
  }

  CXXRecordDecl *ClassDecl = Constructor->getParent();

  // C++ [class.base.init]p2:
  //   Names in a mem-initializer-id are looked up in the scope of the
  //   constructor’s class and, if not found in that scope, are looked
  //   up in the scope containing the constructor’s
  //   definition. [Note: if the constructor’s class contains a member
  //   with the same name as a direct or virtual base class of the
  //   class, a mem-initializer-id naming the member or base class and
  //   composed of a single identifier refers to the class member. A
  //   mem-initializer-id for the hidden base class may be specified
  //   using a qualified name. ]
  // Look for a member, first.
  CXXFieldDecl *Member = ClassDecl->getMember(MemberOrBase);

  // FIXME: Handle members of an anonymous union.

  if (Member) {
    // FIXME: Perform direct initialization of the member.
    return new CXXBaseOrMemberInitializer(Member, (Expr **)Args, NumArgs);
  }

  // It didn't name a member, so see if it names a class.
  TypeTy *BaseTy = isTypeName(*MemberOrBase, S, 0/*SS*/);
  if (!BaseTy)
    return Diag(IdLoc, diag::err_mem_init_not_member_or_class,
                MemberOrBase->getName(), SourceRange(IdLoc, RParenLoc));
  
  QualType BaseType = Context.getTypeDeclType((TypeDecl *)BaseTy);
  if (!BaseType->isRecordType())
    return Diag(IdLoc, diag::err_base_init_does_not_name_class,
                BaseType.getAsString(), SourceRange(IdLoc, RParenLoc));

  // C++ [class.base.init]p2:
  //   [...] Unless the mem-initializer-id names a nonstatic data
  //   member of the constructor’s class or a direct or virtual base
  //   of that class, the mem-initializer is ill-formed. A
  //   mem-initializer-list can initialize a base class using any
  //   name that denotes that base class type.
  
  // First, check for a direct base class.
  const CXXBaseSpecifier *DirectBaseSpec = 0;
  for (CXXRecordDecl::base_class_const_iterator Base = ClassDecl->bases_begin();
       Base != ClassDecl->bases_end(); ++Base) {
    if (Context.getCanonicalType(BaseType).getUnqualifiedType() == 
        Context.getCanonicalType(Base->getType()).getUnqualifiedType()) {
      // We found a direct base of this type. That's what we're
      // initializing.
      DirectBaseSpec = &*Base;
      break;
    }
  }
  
  // Check for a virtual base class.
  // FIXME: We might be able to short-circuit this if we know in
  // advance that there are no virtual bases.
  const CXXBaseSpecifier *VirtualBaseSpec = 0;
  if (!DirectBaseSpec || !DirectBaseSpec->isVirtual()) {
    // We haven't found a base yet; search the class hierarchy for a
    // virtual base class.
    BasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/true,
                    /*DetectVirtual=*/false);
    if (IsDerivedFrom(Context.getTypeDeclType(ClassDecl), BaseType, Paths)) {
      for (BasePaths::paths_iterator Path = Paths.begin(); 
           Path != Paths.end(); ++Path) {
        if (Path->back().Base->isVirtual()) {
          VirtualBaseSpec = Path->back().Base;
          break;
        }
      }
    }
  }

  // C++ [base.class.init]p2:
  //   If a mem-initializer-id is ambiguous because it designates both
  //   a direct non-virtual base class and an inherited virtual base
  //   class, the mem-initializer is ill-formed.
  if (DirectBaseSpec && VirtualBaseSpec)
    return Diag(IdLoc, diag::err_base_init_direct_and_virtual,
                MemberOrBase->getName(), SourceRange(IdLoc, RParenLoc));

  return new CXXBaseOrMemberInitializer(BaseType, (Expr **)Args, NumArgs);
}


void Sema::ActOnFinishCXXMemberSpecification(Scope* S, SourceLocation RLoc,
                                             DeclTy *TagDecl,
                                             SourceLocation LBrac,
                                             SourceLocation RBrac) {
  ActOnFields(S, RLoc, TagDecl,
              (DeclTy**)FieldCollector->getCurFields(),
              FieldCollector->getCurNumFields(), LBrac, RBrac, 0);
}

/// AddImplicitlyDeclaredMembersToClass - Adds any implicitly-declared
/// special functions, such as the default constructor, copy
/// constructor, or destructor, to the given C++ class (C++
/// [special]p1).  This routine can only be executed just before the
/// definition of the class is complete.
void Sema::AddImplicitlyDeclaredMembersToClass(CXXRecordDecl *ClassDecl) {
  QualType ClassType = Context.getTypeDeclType(ClassDecl);
  ClassType = Context.getCanonicalType(ClassType);

  if (!ClassDecl->hasUserDeclaredConstructor()) {
    // C++ [class.ctor]p5:
    //   A default constructor for a class X is a constructor of class X
    //   that can be called without an argument. If there is no
    //   user-declared constructor for class X, a default constructor is
    //   implicitly declared. An implicitly-declared default constructor
    //   is an inline public member of its class.
    DeclarationName Name 
      = Context.DeclarationNames.getCXXConstructorName(ClassType);
    CXXConstructorDecl *DefaultCon = 
      CXXConstructorDecl::Create(Context, ClassDecl,
                                 ClassDecl->getLocation(), Name,
                                 Context.getFunctionType(Context.VoidTy,
                                                         0, 0, false, 0),
                                 /*isExplicit=*/false,
                                 /*isInline=*/true,
                                 /*isImplicitlyDeclared=*/true);
    DefaultCon->setAccess(AS_public);
    ClassDecl->addConstructor(Context, DefaultCon);
  }

  if (!ClassDecl->hasUserDeclaredCopyConstructor()) {
    // C++ [class.copy]p4:
    //   If the class definition does not explicitly declare a copy
    //   constructor, one is declared implicitly.

    // C++ [class.copy]p5:
    //   The implicitly-declared copy constructor for a class X will
    //   have the form
    //
    //       X::X(const X&)
    //
    //   if
    bool HasConstCopyConstructor = true;

    //     -- each direct or virtual base class B of X has a copy
    //        constructor whose first parameter is of type const B& or
    //        const volatile B&, and
    for (CXXRecordDecl::base_class_iterator Base = ClassDecl->bases_begin();
         HasConstCopyConstructor && Base != ClassDecl->bases_end(); ++Base) {
      const CXXRecordDecl *BaseClassDecl
        = cast<CXXRecordDecl>(Base->getType()->getAsRecordType()->getDecl());
      HasConstCopyConstructor 
        = BaseClassDecl->hasConstCopyConstructor(Context);
    }

    //     -- for all the nonstatic data members of X that are of a
    //        class type M (or array thereof), each such class type
    //        has a copy constructor whose first parameter is of type
    //        const M& or const volatile M&.
    for (CXXRecordDecl::field_iterator Field = ClassDecl->field_begin();
         HasConstCopyConstructor && Field != ClassDecl->field_end(); ++Field) {
      QualType FieldType = (*Field)->getType();
      if (const ArrayType *Array = Context.getAsArrayType(FieldType))
        FieldType = Array->getElementType();
      if (const RecordType *FieldClassType = FieldType->getAsRecordType()) {
        const CXXRecordDecl *FieldClassDecl 
          = cast<CXXRecordDecl>(FieldClassType->getDecl());
        HasConstCopyConstructor 
          = FieldClassDecl->hasConstCopyConstructor(Context);
      }
    }

    //  Otherwise, the implicitly declared copy constructor will have
    //  the form
    //
    //       X::X(X&)
    QualType ArgType = Context.getTypeDeclType(ClassDecl);
    if (HasConstCopyConstructor)
      ArgType = ArgType.withConst();
    ArgType = Context.getReferenceType(ArgType);

    //  An implicitly-declared copy constructor is an inline public
    //  member of its class.
    DeclarationName Name 
      = Context.DeclarationNames.getCXXConstructorName(ClassType);
    CXXConstructorDecl *CopyConstructor
      = CXXConstructorDecl::Create(Context, ClassDecl,
                                   ClassDecl->getLocation(), Name,
                                   Context.getFunctionType(Context.VoidTy,
                                                           &ArgType, 1,
                                                           false, 0),
                                   /*isExplicit=*/false,
                                   /*isInline=*/true,
                                   /*isImplicitlyDeclared=*/true);
    CopyConstructor->setAccess(AS_public);

    // Add the parameter to the constructor.
    ParmVarDecl *FromParam = ParmVarDecl::Create(Context, CopyConstructor,
                                                 ClassDecl->getLocation(),
                                                 /*IdentifierInfo=*/0,
                                                 ArgType, VarDecl::None, 0, 0);
    CopyConstructor->setParams(&FromParam, 1);

    ClassDecl->addConstructor(Context, CopyConstructor);
  }

  if (!ClassDecl->getDestructor()) {
    // C++ [class.dtor]p2:
    //   If a class has no user-declared destructor, a destructor is
    //   declared implicitly. An implicitly-declared destructor is an
    //   inline public member of its class.
    DeclarationName Name 
      = Context.DeclarationNames.getCXXDestructorName(ClassType);
    CXXDestructorDecl *Destructor 
      = CXXDestructorDecl::Create(Context, ClassDecl,
                                  ClassDecl->getLocation(), Name,
                                  Context.getFunctionType(Context.VoidTy,
                                                          0, 0, false, 0),
                                  /*isInline=*/true,
                                  /*isImplicitlyDeclared=*/true);
    Destructor->setAccess(AS_public);
    ClassDecl->setDestructor(Destructor);
  }

  // FIXME: Implicit copy assignment operator
}

void Sema::ActOnFinishCXXClassDef(DeclTy *D) {
  CXXRecordDecl *Rec = cast<CXXRecordDecl>(static_cast<Decl *>(D));
  FieldCollector->FinishClass();
  AddImplicitlyDeclaredMembersToClass(Rec);
  PopDeclContext();

  // Everything, including inline method definitions, have been parsed.
  // Let the consumer know of the new TagDecl definition.
  Consumer.HandleTagDeclDefinition(Rec);
}

/// CheckConstructorDeclarator - Called by ActOnDeclarator to check
/// the well-formednes of the constructor declarator @p D with type @p
/// R. If there are any errors in the declarator, this routine will
/// emit diagnostics and return true. Otherwise, it will return
/// false. Either way, the type @p R will be updated to reflect a
/// well-formed type for the constructor.
bool Sema::CheckConstructorDeclarator(Declarator &D, QualType &R,
                                      FunctionDecl::StorageClass& SC) {
  bool isVirtual = D.getDeclSpec().isVirtualSpecified();
  bool isInvalid = false;

  // C++ [class.ctor]p3:
  //   A constructor shall not be virtual (10.3) or static (9.4). A
  //   constructor can be invoked for a const, volatile or const
  //   volatile object. A constructor shall not be declared const,
  //   volatile, or const volatile (9.3.2).
  if (isVirtual) {
    Diag(D.getIdentifierLoc(),
         diag::err_constructor_cannot_be,
         "virtual",
         SourceRange(D.getDeclSpec().getVirtualSpecLoc()),
         SourceRange(D.getIdentifierLoc()));
    isInvalid = true;
  }
  if (SC == FunctionDecl::Static) {
    Diag(D.getIdentifierLoc(),
         diag::err_constructor_cannot_be,
         "static",
         SourceRange(D.getDeclSpec().getStorageClassSpecLoc()),
         SourceRange(D.getIdentifierLoc()));
    isInvalid = true;
    SC = FunctionDecl::None;
  }
  if (D.getDeclSpec().hasTypeSpecifier()) {
    // Constructors don't have return types, but the parser will
    // happily parse something like:
    //
    //   class X {
    //     float X(float);
    //   };
    //
    // The return type will be eliminated later.
    Diag(D.getIdentifierLoc(),
         diag::err_constructor_return_type,
         SourceRange(D.getDeclSpec().getTypeSpecTypeLoc()),
         SourceRange(D.getIdentifierLoc()));
  } 
  if (R->getAsFunctionTypeProto()->getTypeQuals() != 0) {
    DeclaratorChunk::FunctionTypeInfo &FTI = D.getTypeObject(0).Fun;
    if (FTI.TypeQuals & QualType::Const)
      Diag(D.getIdentifierLoc(),
           diag::err_invalid_qualified_constructor,
           "const",
           SourceRange(D.getIdentifierLoc()));
    if (FTI.TypeQuals & QualType::Volatile)
      Diag(D.getIdentifierLoc(),
           diag::err_invalid_qualified_constructor,
           "volatile",
           SourceRange(D.getIdentifierLoc()));
    if (FTI.TypeQuals & QualType::Restrict)
      Diag(D.getIdentifierLoc(),
           diag::err_invalid_qualified_constructor,
           "restrict",
           SourceRange(D.getIdentifierLoc()));
  }
      
  // Rebuild the function type "R" without any type qualifiers (in
  // case any of the errors above fired) and with "void" as the
  // return type, since constructors don't have return types. We
  // *always* have to do this, because GetTypeForDeclarator will
  // put in a result type of "int" when none was specified.
  const FunctionTypeProto *Proto = R->getAsFunctionTypeProto();
  R = Context.getFunctionType(Context.VoidTy, Proto->arg_type_begin(),
                              Proto->getNumArgs(),
                              Proto->isVariadic(),
                              0);

  return isInvalid;
}

/// CheckDestructorDeclarator - Called by ActOnDeclarator to check
/// the well-formednes of the destructor declarator @p D with type @p
/// R. If there are any errors in the declarator, this routine will
/// emit diagnostics and return true. Otherwise, it will return
/// false. Either way, the type @p R will be updated to reflect a
/// well-formed type for the destructor.
bool Sema::CheckDestructorDeclarator(Declarator &D, QualType &R,
                                     FunctionDecl::StorageClass& SC) {
  bool isInvalid = false;

  // C++ [class.dtor]p1:
  //   [...] A typedef-name that names a class is a class-name
  //   (7.1.3); however, a typedef-name that names a class shall not
  //   be used as the identifier in the declarator for a destructor
  //   declaration.
  TypeDecl *DeclaratorTypeD = (TypeDecl *)D.getDeclaratorIdType();
  if (const TypedefDecl *TypedefD = dyn_cast<TypedefDecl>(DeclaratorTypeD)) {
    Diag(D.getIdentifierLoc(), 
         diag::err_destructor_typedef_name,
         TypedefD->getName());
    isInvalid = true;
  }

  // C++ [class.dtor]p2:
  //   A destructor is used to destroy objects of its class type. A
  //   destructor takes no parameters, and no return type can be
  //   specified for it (not even void). The address of a destructor
  //   shall not be taken. A destructor shall not be static. A
  //   destructor can be invoked for a const, volatile or const
  //   volatile object. A destructor shall not be declared const,
  //   volatile or const volatile (9.3.2).
  if (SC == FunctionDecl::Static) {
    Diag(D.getIdentifierLoc(),
         diag::err_destructor_cannot_be,
         "static",
         SourceRange(D.getDeclSpec().getStorageClassSpecLoc()),
         SourceRange(D.getIdentifierLoc()));
    isInvalid = true;
    SC = FunctionDecl::None;
  }
  if (D.getDeclSpec().hasTypeSpecifier()) {
    // Destructors don't have return types, but the parser will
    // happily parse something like:
    //
    //   class X {
    //     float ~X();
    //   };
    //
    // The return type will be eliminated later.
    Diag(D.getIdentifierLoc(),
         diag::err_destructor_return_type,
         SourceRange(D.getDeclSpec().getTypeSpecTypeLoc()),
         SourceRange(D.getIdentifierLoc()));
  }
  if (R->getAsFunctionTypeProto()->getTypeQuals() != 0) {
    DeclaratorChunk::FunctionTypeInfo &FTI = D.getTypeObject(0).Fun;
    if (FTI.TypeQuals & QualType::Const)
      Diag(D.getIdentifierLoc(),
           diag::err_invalid_qualified_destructor,
           "const",