lib/Parse/ParseDeclCXX.cpp

//===--- ParseDeclCXX.cpp - C++ Declaration Parsing -----------------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
//  This file implements the C++ Declaration portions of the Parser interfaces.
//
//===----------------------------------------------------------------------===//

#include "clang/Parse/Parser.h"
#include "clang/Parse/ParseDiagnostic.h"
#include "clang/Parse/DeclSpec.h"
#include "clang/Parse/Scope.h"
#include "ExtensionRAIIObject.h"
using namespace clang;

/// ParseNamespace - We know that the current token is a namespace keyword. This
/// may either be a top level namespace or a block-level namespace alias.
///
///       namespace-definition: [C++ 7.3: basic.namespace]
///         named-namespace-definition
///         unnamed-namespace-definition
///
///       unnamed-namespace-definition:
///         'namespace' attributes[opt] '{' namespace-body '}'
///
///       named-namespace-definition:
///         original-namespace-definition
///         extension-namespace-definition
///
///       original-namespace-definition:
///         'namespace' identifier attributes[opt] '{' namespace-body '}'
///
///       extension-namespace-definition:
///         'namespace' original-namespace-name '{' namespace-body '}'
///  
///       namespace-alias-definition:  [C++ 7.3.2: namespace.alias]
///         'namespace' identifier '=' qualified-namespace-specifier ';'
///
Parser::DeclPtrTy Parser::ParseNamespace(unsigned Context,
                                         SourceLocation &DeclEnd) {
  assert(Tok.is(tok::kw_namespace) && "Not a namespace!");
  SourceLocation NamespaceLoc = ConsumeToken();  // eat the 'namespace'.
  
  SourceLocation IdentLoc;
  IdentifierInfo *Ident = 0;

  Token attrTok;
  
  if (Tok.is(tok::identifier)) {
    Ident = Tok.getIdentifierInfo();
    IdentLoc = ConsumeToken();  // eat the identifier.
  }
  
  // Read label attributes, if present.
  Action::AttrTy *AttrList = 0;
  if (Tok.is(tok::kw___attribute)) {
    attrTok = Tok;

    // FIXME: save these somewhere.
    AttrList = ParseAttributes();
  }
  
  if (Tok.is(tok::equal)) {
    if (AttrList)
      Diag(attrTok, diag::err_unexpected_namespace_attributes_alias);

    return ParseNamespaceAlias(NamespaceLoc, IdentLoc, Ident, DeclEnd);
  }
  
  if (Tok.isNot(tok::l_brace)) {
    Diag(Tok, Ident ? diag::err_expected_lbrace : 
         diag::err_expected_ident_lbrace);
    return DeclPtrTy();
  }
  
  SourceLocation LBrace = ConsumeBrace();

  // Enter a scope for the namespace.
  ParseScope NamespaceScope(this, Scope::DeclScope);

  DeclPtrTy NamespcDecl =
    Actions.ActOnStartNamespaceDef(CurScope, IdentLoc, Ident, LBrace);

  PrettyStackTraceActionsDecl CrashInfo(NamespcDecl, NamespaceLoc, Actions,
                                        PP.getSourceManager(),
                                        "parsing namespace");
  
  while (Tok.isNot(tok::r_brace) && Tok.isNot(tok::eof))
    ParseExternalDeclaration();
  
  // Leave the namespace scope.
  NamespaceScope.Exit();

  SourceLocation RBraceLoc = MatchRHSPunctuation(tok::r_brace, LBrace);
  Actions.ActOnFinishNamespaceDef(NamespcDecl, RBraceLoc);

  DeclEnd = RBraceLoc;
  return NamespcDecl;
}

/// ParseNamespaceAlias - Parse the part after the '=' in a namespace
/// alias definition.
///
Parser::DeclPtrTy Parser::ParseNamespaceAlias(SourceLocation NamespaceLoc,
                                              SourceLocation AliasLoc, 
                                              IdentifierInfo *Alias,
                                              SourceLocation &DeclEnd) {
  assert(Tok.is(tok::equal) && "Not equal token");
  
  ConsumeToken(); // eat the '='.
  
  CXXScopeSpec SS;
  // Parse (optional) nested-name-specifier.
  ParseOptionalCXXScopeSpecifier(SS);

  if (SS.isInvalid() || Tok.isNot(tok::identifier)) {
    Diag(Tok, diag::err_expected_namespace_name);
    // Skip to end of the definition and eat the ';'.
    SkipUntil(tok::semi);
    return DeclPtrTy();
  }

  // Parse identifier.
  IdentifierInfo *Ident = Tok.getIdentifierInfo();
  SourceLocation IdentLoc = ConsumeToken();
  
  // Eat the ';'.
  DeclEnd = Tok.getLocation();
  ExpectAndConsume(tok::semi, diag::err_expected_semi_after_namespace_name,
                   "", tok::semi);
  
  return Actions.ActOnNamespaceAliasDef(CurScope, NamespaceLoc, AliasLoc, Alias, 
                                        SS, IdentLoc, Ident);
}

/// ParseLinkage - We know that the current token is a string_literal
/// and just before that, that extern was seen.
///
///       linkage-specification: [C++ 7.5p2: dcl.link]
///         'extern' string-literal '{' declaration-seq[opt] '}'
///         'extern' string-literal declaration
///
Parser::DeclPtrTy Parser::ParseLinkage(unsigned Context) {
  assert(Tok.is(tok::string_literal) && "Not a string literal!");
  llvm::SmallVector<char, 8> LangBuffer;
  // LangBuffer is guaranteed to be big enough.
  LangBuffer.resize(Tok.getLength());
  const char *LangBufPtr = &LangBuffer[0];
  unsigned StrSize = PP.getSpelling(Tok, LangBufPtr);

  SourceLocation Loc = ConsumeStringToken();

  ParseScope LinkageScope(this, Scope::DeclScope);
  DeclPtrTy LinkageSpec 
    = Actions.ActOnStartLinkageSpecification(CurScope, 
                                             /*FIXME: */SourceLocation(),
                                             Loc, LangBufPtr, StrSize,
                                       Tok.is(tok::l_brace)? Tok.getLocation() 
                                                           : SourceLocation());

  if (Tok.isNot(tok::l_brace)) {
    ParseDeclarationOrFunctionDefinition();
    return Actions.ActOnFinishLinkageSpecification(CurScope, LinkageSpec, 
                                                   SourceLocation());
  } 

  SourceLocation LBrace = ConsumeBrace();
  while (Tok.isNot(tok::r_brace) && Tok.isNot(tok::eof)) {
    ParseExternalDeclaration();
  }

  SourceLocation RBrace = MatchRHSPunctuation(tok::r_brace, LBrace);
  return Actions.ActOnFinishLinkageSpecification(CurScope, LinkageSpec, RBrace);
}

/// ParseUsingDirectiveOrDeclaration - Parse C++ using using-declaration or
/// using-directive. Assumes that current token is 'using'.
Parser::DeclPtrTy Parser::ParseUsingDirectiveOrDeclaration(unsigned Context,
                                                     SourceLocation &DeclEnd) {
  assert(Tok.is(tok::kw_using) && "Not using token");

  // Eat 'using'.
  SourceLocation UsingLoc = ConsumeToken();

  if (Tok.is(tok::kw_namespace))
    // Next token after 'using' is 'namespace' so it must be using-directive
    return ParseUsingDirective(Context, UsingLoc, DeclEnd);

  // Otherwise, it must be using-declaration.
  return ParseUsingDeclaration(Context, UsingLoc, DeclEnd);
}

/// ParseUsingDirective - Parse C++ using-directive, assumes
/// that current token is 'namespace' and 'using' was already parsed.
///
///       using-directive: [C++ 7.3.p4: namespace.udir]
///        'using' 'namespace' ::[opt] nested-name-specifier[opt]
///                 namespace-name ;
/// [GNU] using-directive:
///        'using' 'namespace' ::[opt] nested-name-specifier[opt]
///                 namespace-name attributes[opt] ;
///
Parser::DeclPtrTy Parser::ParseUsingDirective(unsigned Context,
                                              SourceLocation UsingLoc,
                                              SourceLocation &DeclEnd) {
  assert(Tok.is(tok::kw_namespace) && "Not 'namespace' token");

  // Eat 'namespace'.
  SourceLocation NamespcLoc = ConsumeToken();

  CXXScopeSpec SS;
  // Parse (optional) nested-name-specifier.
  ParseOptionalCXXScopeSpecifier(SS);

  AttributeList *AttrList = 0;
  IdentifierInfo *NamespcName = 0;
  SourceLocation IdentLoc = SourceLocation();

  // Parse namespace-name.
  if (SS.isInvalid() || Tok.isNot(tok::identifier)) {
    Diag(Tok, diag::err_expected_namespace_name);
    // If there was invalid namespace name, skip to end of decl, and eat ';'.
    SkipUntil(tok::semi);
    // FIXME: Are there cases, when we would like to call ActOnUsingDirective?
    return DeclPtrTy();
  }
  
  // Parse identifier.
  NamespcName = Tok.getIdentifierInfo();
  IdentLoc = ConsumeToken();
  
  // Parse (optional) attributes (most likely GNU strong-using extension).
  if (Tok.is(tok::kw___attribute))
    AttrList = ParseAttributes();
  
  // Eat ';'.
  DeclEnd = Tok.getLocation();
  ExpectAndConsume(tok::semi,
                   AttrList ? diag::err_expected_semi_after_attribute_list :
                   diag::err_expected_semi_after_namespace_name, "", tok::semi);

  return Actions.ActOnUsingDirective(CurScope, UsingLoc, NamespcLoc, SS,
                                      IdentLoc, NamespcName, AttrList);
}

/// ParseUsingDeclaration - Parse C++ using-declaration. Assumes that
/// 'using' was already seen.
///
///     using-declaration: [C++ 7.3.p3: namespace.udecl]
///       'using' 'typename'[opt] ::[opt] nested-name-specifier
///               unqualified-id
///       'using' :: unqualified-id
///
Parser::DeclPtrTy Parser::ParseUsingDeclaration(unsigned Context,
                                                SourceLocation UsingLoc,
                                                SourceLocation &DeclEnd) {
  CXXScopeSpec SS;
  bool IsTypeName;

  // Ignore optional 'typename'.
  if (Tok.is(tok::kw_typename)) {
    ConsumeToken();
    IsTypeName = true;
  }
  else
    IsTypeName = false;

  // Parse nested-name-specifier.
  ParseOptionalCXXScopeSpecifier(SS);

  AttributeList *AttrList = 0;
  IdentifierInfo *TargetName = 0;
  SourceLocation IdentLoc = SourceLocation();

  // Check nested-name specifier.
  if (SS.isInvalid()) {
    SkipUntil(tok::semi);
    return DeclPtrTy();
  }
  if (Tok.is(tok::annot_template_id)) {
    Diag(Tok, diag::err_unexpected_template_spec_in_using);
    SkipUntil(tok::semi);
    return DeclPtrTy();
  }
  if (Tok.isNot(tok::identifier)) {
    Diag(Tok, diag::err_expected_ident_in_using);
    // If there was invalid identifier, skip to end of decl, and eat ';'.
    SkipUntil(tok::semi);
    return DeclPtrTy();
  }
  
  // Parse identifier.
  TargetName = Tok.getIdentifierInfo();
  IdentLoc = ConsumeToken();
  
  // Parse (optional) attributes (most likely GNU strong-using extension).
  if (Tok.is(tok::kw___attribute))
    AttrList = ParseAttributes();
  
  // Eat ';'.
  DeclEnd = Tok.getLocation();
  ExpectAndConsume(tok::semi, diag::err_expected_semi_after,
                   AttrList ? "attributes list" : "namespace name", tok::semi);

  return Actions.ActOnUsingDeclaration(CurScope, UsingLoc, SS,
                                      IdentLoc, TargetName, AttrList, IsTypeName);
}

/// ParseStaticAssertDeclaration - Parse C++0x static_assert-declaratoion.
///
///      static_assert-declaration:
///        static_assert ( constant-expression  ,  string-literal  ) ;
///
Parser::DeclPtrTy Parser::ParseStaticAssertDeclaration(SourceLocation &DeclEnd){
  assert(Tok.is(tok::kw_static_assert) && "Not a static_assert declaration");
  SourceLocation StaticAssertLoc = ConsumeToken();
  
  if (Tok.isNot(tok::l_paren)) {
    Diag(Tok, diag::err_expected_lparen);
    return DeclPtrTy();
  }
  
  SourceLocation LParenLoc = ConsumeParen();

  OwningExprResult AssertExpr(ParseConstantExpression());
  if (AssertExpr.isInvalid()) {
    SkipUntil(tok::semi);
    return DeclPtrTy();
  }
  
  if (ExpectAndConsume(tok::comma, diag::err_expected_comma, "", tok::semi))
    return DeclPtrTy();

  if (Tok.isNot(tok::string_literal)) {
    Diag(Tok, diag::err_expected_string_literal);
    SkipUntil(tok::semi);
    return DeclPtrTy();
  }
  
  OwningExprResult AssertMessage(ParseStringLiteralExpression());
  if (AssertMessage.isInvalid()) 
    return DeclPtrTy();

  MatchRHSPunctuation(tok::r_paren, LParenLoc);
  
  DeclEnd = Tok.getLocation();
  ExpectAndConsume(tok::semi, diag::err_expected_semi_after_static_assert);

  return Actions.ActOnStaticAssertDeclaration(StaticAssertLoc, move(AssertExpr), 
                                              move(AssertMessage));
}

/// ParseDecltypeSpecifier - Parse a C++0x decltype specifier.
///
/// 'decltype' ( expression )
///
void Parser::ParseDecltypeSpecifier(DeclSpec &DS) {
  assert(Tok.is(tok::kw_decltype) && "Not a decltype specifier");

  SourceLocation StartLoc = ConsumeToken();
  SourceLocation LParenLoc = Tok.getLocation();
  
  if (ExpectAndConsume(tok::l_paren, diag::err_expected_lparen_after, 
                       "decltype")) {
    SkipUntil(tok::r_paren);
    return;
  }
  
  // Parse the expression
  
  // C++0x [dcl.type.simple]p4:
  //   The operand of the decltype specifier is an unevaluated operand.
  EnterExpressionEvaluationContext Unevaluated(Actions,
                                               Action::Unevaluated);
  OwningExprResult Result = ParseExpression();
  if (Result.isInvalid()) {
    SkipUntil(tok::r_paren);
    return;
  }
  
  // Match the ')'
  SourceLocation RParenLoc;
  if (Tok.is(tok::r_paren))
    RParenLoc = ConsumeParen();
  else
    MatchRHSPunctuation(tok::r_paren, LParenLoc);
  
  if (RParenLoc.isInvalid())
    return;

  const char *PrevSpec = 0;
  // Check for duplicate type specifiers (e.g. "int decltype(a)").
  if (DS.SetTypeSpecType(DeclSpec::TST_decltype, StartLoc, PrevSpec, 
                         Result.release()))
    Diag(StartLoc, diag::err_invalid_decl_spec_combination) << PrevSpec;
}

/// ParseClassName - Parse a C++ class-name, which names a class. Note
/// that we only check that the result names a type; semantic analysis
/// will need to verify that the type names a class. The result is
/// either a type or NULL, depending on whether a type name was
/// found.
///
///       class-name: [C++ 9.1]
///         identifier
///         simple-template-id
/// 
Parser::TypeResult Parser::ParseClassName(SourceLocation &EndLocation,
                                          const CXXScopeSpec *SS) {
  // Check whether we have a template-id that names a type.
  if (Tok.is(tok::annot_template_id)) {
    TemplateIdAnnotation *TemplateId 
      = static_cast<TemplateIdAnnotation *>(Tok.getAnnotationValue());
    if (TemplateId->Kind == TNK_Type_template) {
      AnnotateTemplateIdTokenAsType(SS);

      assert(Tok.is(tok::annot_typename) && "template-id -> type failed");
      TypeTy *Type = Tok.getAnnotationValue();
      EndLocation = Tok.getAnnotationEndLoc();
      ConsumeToken();

      if (Type)
        return Type;
      return true;
    }

    // Fall through to produce an error below.
  }

  if (Tok.isNot(tok::identifier)) {
    Diag(Tok, diag::err_expected_class_name);
    return true;
  }

  // We have an identifier; check whether it is actually a type.
  TypeTy *Type = Actions.getTypeName(*Tok.getIdentifierInfo(), 
                                     Tok.getLocation(), CurScope, SS);
  if (!Type) {
    Diag(Tok, diag::err_expected_class_name);
    return true;
  }

  // Consume the identifier.
  EndLocation = ConsumeToken();
  return Type;
}

/// ParseClassSpecifier - Parse a C++ class-specifier [C++ class] or
/// elaborated-type-specifier [C++ dcl.type.elab]; we can't tell which
/// until we reach the start of a definition or see a token that
/// cannot start a definition.
///
///       class-specifier: [C++ class]
///         class-head '{' member-specification[opt] '}'
///         class-head '{' member-specification[opt] '}' attributes[opt]
///       class-head:
///         class-key identifier[opt] base-clause[opt]
///         class-key nested-name-specifier identifier base-clause[opt]
///         class-key nested-name-specifier[opt] simple-template-id
///                          base-clause[opt]
/// [GNU]   class-key attributes[opt] identifier[opt] base-clause[opt]
/// [GNU]   class-key attributes[opt] nested-name-specifier 
///                          identifier base-clause[opt]
/// [GNU]   class-key attributes[opt] nested-name-specifier[opt] 
///                          simple-template-id base-clause[opt]
///       class-key:
///         'class'
///         'struct'
///         'union'
///
///       elaborated-type-specifier: [C++ dcl.type.elab]
///         class-key ::[opt] nested-name-specifier[opt] identifier 
///         class-key ::[opt] nested-name-specifier[opt] 'template'[opt] 
///                          simple-template-id 
///
///  Note that the C++ class-specifier and elaborated-type-specifier,
///  together, subsume the C99 struct-or-union-specifier:
///
///       struct-or-union-specifier: [C99 6.7.2.1]
///         struct-or-union identifier[opt] '{' struct-contents '}'
///         struct-or-union identifier
/// [GNU]   struct-or-union attributes[opt] identifier[opt] '{' struct-contents
///                                                         '}' attributes[opt]
/// [GNU]   struct-or-union attributes[opt] identifier
///       struct-or-union:
///         'struct'
///         'union'
void Parser::ParseClassSpecifier(tok::TokenKind TagTokKind,
                                 SourceLocation StartLoc, DeclSpec &DS,
                                 const ParsedTemplateInfo &TemplateInfo,
                                 AccessSpecifier AS) {
  DeclSpec::TST TagType;
  if (TagTokKind == tok::kw_struct)
    TagType = DeclSpec::TST_struct;
  else if (TagTokKind == tok::kw_class)
    TagType = DeclSpec::TST_class;
  else {
    assert(TagTokKind == tok::kw_union && "Not a class specifier");
    TagType = DeclSpec::TST_union;
  }

  AttributeList *Attr = 0;
  // If attributes exist after tag, parse them.
  if (Tok.is(tok::kw___attribute))
    Attr = ParseAttributes();

  // If declspecs exist after tag, parse them.
  if (Tok.is(tok::kw___declspec))
    Attr = ParseMicrosoftDeclSpec(Attr);
  
  // Parse the (optional) nested-name-specifier.
  CXXScopeSpec SS;
  if (getLang().CPlusPlus && ParseOptionalCXXScopeSpecifier(SS))
    if (Tok.isNot(tok::identifier) && Tok.isNot(tok::annot_template_id))
      Diag(Tok, diag::err_expected_ident);

  // Parse the (optional) class name or simple-template-id.
  IdentifierInfo *Name = 0;
  SourceLocation NameLoc;
  TemplateIdAnnotation *TemplateId = 0;
  if (Tok.is(tok::identifier)) {
    Name = Tok.getIdentifierInfo();
    NameLoc = ConsumeToken();
  } else if (Tok.is(tok::annot_template_id)) {
    TemplateId = static_cast<TemplateIdAnnotation *>(Tok.getAnnotationValue());
    NameLoc = ConsumeToken();

    if (TemplateId->Kind != TNK_Type_template) {
      // The template-name in the simple-template-id refers to
      // something other than a class template. Give an appropriate
      // error message and skip to the ';'.
      SourceRange Range(NameLoc);
      if (SS.isNotEmpty())
        Range.setBegin(SS.getBeginLoc());

      Diag(TemplateId->LAngleLoc, diag::err_template_spec_syntax_non_template)
        << Name << static_cast<int>(TemplateId->Kind) << Range;
      
      DS.SetTypeSpecError();
      SkipUntil(tok::semi, false, true);
      TemplateId->Destroy();
      return;
    }
  }

  // There are three options here.  If we have 'struct foo;', then
  // this is a forward declaration.  If we have 'struct foo {...' or
  // 'struct foo :...' then this is a definition. Otherwise we have
  // something like 'struct foo xyz', a reference.
  Action::TagKind TK;
  if (Tok.is(tok::l_brace) || (getLang().CPlusPlus && Tok.is(tok::colon)))
    TK = Action::TK_Definition;
  else if (Tok.is(tok::semi) && !DS.isFriendSpecified())
    TK = Action::TK_Declaration;
  else
    TK = Action::TK_Reference;

  if (!Name && !TemplateId && TK != Action::TK_Definition) {
    // We have a declaration or reference to an anonymous class.
    Diag(StartLoc, diag::err_anon_type_definition)
      << DeclSpec::getSpecifierName(TagType);

    // Skip the rest of this declarator, up until the comma or semicolon.
    SkipUntil(tok::comma, true);

    if (TemplateId)
      TemplateId->Destroy();
    return;
  }

  // Create the tag portion of the class or class template.
  Action::DeclResult TagOrTempResult;
  TemplateParameterLists *TemplateParams = TemplateInfo.TemplateParams;

  // FIXME: When TK == TK_Reference and we have a template-id, we need
  // to turn that template-id into a type.

  bool Owned = false;
  if (TemplateId && TK != Action::TK_Reference) {
    // Explicit specialization, class template partial specialization,
    // or explicit instantiation.
    ASTTemplateArgsPtr TemplateArgsPtr(Actions, 
                                       TemplateId->getTemplateArgs(),
                                       TemplateId->getTemplateArgIsType(),
                                       TemplateId->NumArgs);
    if (TemplateInfo.Kind == ParsedTemplateInfo::ExplicitInstantiation &&
        TK == Action::TK_Declaration) {
      // This is an explicit instantiation of a class template.
      TagOrTempResult
        = Actions.ActOnExplicitInstantiation(CurScope, 
                                             TemplateInfo.TemplateLoc, 
                                             TagType,
                                             StartLoc, 
                                             SS,
                                     TemplateTy::make(TemplateId->Template), 
                                             TemplateId->TemplateNameLoc, 
                                             TemplateId->LAngleLoc, 
                                             TemplateArgsPtr,
                                      TemplateId->getTemplateArgLocations(),
                                             TemplateId->RAngleLoc, 
                                             Attr);
    } else {
      // This is an explicit specialization or a class template
      // partial specialization.
      TemplateParameterLists FakedParamLists;

      if (TemplateInfo.Kind == ParsedTemplateInfo::ExplicitInstantiation) {
        // This looks like an explicit instantiation, because we have
        // something like
        //
        //   template class Foo<X>
        //
        // but it actually has a definition. Most likely, this was
        // meant to be an explicit specialization, but the user forgot
        // the '<>' after 'template'.
        assert(TK == Action::TK_Definition && "Expected a definition here");

        SourceLocation LAngleLoc 
          = PP.getLocForEndOfToken(TemplateInfo.TemplateLoc);
        Diag(TemplateId->TemplateNameLoc, 
             diag::err_explicit_instantiation_with_definition)
          << SourceRange(TemplateInfo.TemplateLoc)
          << CodeModificationHint::CreateInsertion(LAngleLoc, "<>");

        // Create a fake template parameter list that contains only
        // "template<>", so that we treat this construct as a class
        // template specialization.
        FakedParamLists.push_back(
          Actions.ActOnTemplateParameterList(0, SourceLocation(), 
                                             TemplateInfo.TemplateLoc,
                                             LAngleLoc, 
                                             0, 0, 
                                             LAngleLoc));
        TemplateParams = &FakedParamLists;
      }

      // Build the class template specialization.
      TagOrTempResult
        = Actions.ActOnClassTemplateSpecialization(CurScope, TagType, TK,
                       StartLoc, SS,
                       TemplateTy::make(TemplateId->Template), 
                       TemplateId->TemplateNameLoc, 
                       TemplateId->LAngleLoc, 
                       TemplateArgsPtr,
                       TemplateId->getTemplateArgLocations(),
                       TemplateId->RAngleLoc, 
                       Attr,
                       Action::MultiTemplateParamsArg(Actions, 
                                    TemplateParams? &(*TemplateParams)[0] : 0,
                                 TemplateParams? TemplateParams->size() : 0));
    }
    TemplateId->Destroy();
  } else if (TemplateParams && TK != Action::TK_Reference) {
    // Class template declaration or definition.
    TagOrTempResult = Actions.ActOnClassTemplate(CurScope, TagType, TK, 
                                                 StartLoc, SS, Name, NameLoc, 
                                                 Attr,
                       Action::MultiTemplateParamsArg(Actions, 
                                                      &(*TemplateParams)[0],
                                                      TemplateParams->size()),
                                                 AS);
  } else if (TemplateInfo.Kind == ParsedTemplateInfo::ExplicitInstantiation &&
             TK == Action::TK_Declaration) {
    // Explicit instantiation of a member of a class template
    // specialization, e.g.,
    //
    //   template struct Outer<int>::Inner;
    //
    TagOrTempResult
      = Actions.ActOnExplicitInstantiation(CurScope, 
                                           TemplateInfo.TemplateLoc, 
                                           TagType, StartLoc, SS, Name, 
                                           NameLoc, Attr);
  } else {
    if (TemplateInfo.Kind == ParsedTemplateInfo::ExplicitInstantiation &&
        TK == Action::TK_Definition) {
      // FIXME: Diagnose this particular error.
    }

    // Declaration or definition of a class type
    TagOrTempResult = Actions.ActOnTag(CurScope, TagType, TK, StartLoc, SS, 
                                       Name, NameLoc, Attr, AS, Owned);
  }

  // Parse the optional base clause (C++ only).
  if (getLang().CPlusPlus && Tok.is(tok::colon))
    ParseBaseClause(TagOrTempResult.get());

  // If there is a body, parse it and inform the actions module.
  if (Tok.is(tok::l_brace))
    if (getLang().CPlusPlus)
      ParseCXXMemberSpecification(StartLoc, TagType, TagOrTempResult.get());
    else
      ParseStructUnionBody(StartLoc, TagType, TagOrTempResult.get());
  else if (TK == Action::TK_Definition) {
    // FIXME: Complain that we have a base-specifier list but no
    // definition.
    Diag(Tok, diag::err_expected_lbrace);
  }

  const char *PrevSpec = 0;
  if (TagOrTempResult.isInvalid()) {
    DS.SetTypeSpecError();
    return;
  }
  
  if (DS.SetTypeSpecType(TagType, StartLoc, PrevSpec, 
                         TagOrTempResult.get().getAs<void>(), Owned))
    Diag(StartLoc, diag::err_invalid_decl_spec_combination) << PrevSpec;
  
  if (DS.isFriendSpecified())
    Actions.ActOnFriendDecl(CurScope, DS.getFriendSpecLoc(), 
                            TagOrTempResult.get());
}

/// ParseBaseClause - Parse the base-clause of a C++ class [C++ class.derived]. 
///
///       base-clause : [C++ class.derived]
///         ':' base-specifier-list
///       base-specifier-list:
///         base-specifier '...'[opt]
///         base-specifier-list ',' base-specifier '...'[opt]
void Parser::ParseBaseClause(DeclPtrTy ClassDecl) {
  assert(Tok.is(tok::colon) && "Not a base clause");
  ConsumeToken();

  // Build up an array of parsed base specifiers.
  llvm::SmallVector<BaseTy *, 8> BaseInfo;

  while (true) {
    // Parse a base-specifier.
    BaseResult Result = ParseBaseSpecifier(ClassDecl);
    if (Result.isInvalid()) {
      // Skip the rest of this base specifier, up until the comma or
      // opening brace.
      SkipUntil(tok::comma, tok::l_brace, true, true);
    } else {
      // Add this to our array of base specifiers.
      BaseInfo.push_back(Result.get());
    }

    // If the next token is a comma, consume it and keep reading
    // base-specifiers.
    if (Tok.isNot(tok::comma)) break;
    
    // Consume the comma.
    ConsumeToken();
  }

  // Attach the base specifiers
  Actions.ActOnBaseSpecifiers(ClassDecl, BaseInfo.data(), BaseInfo.size());
}

/// ParseBaseSpecifier - Parse a C++ 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.
///
///       base-specifier: [C++ class.derived]
///         ::[opt] nested-name-specifier[opt] class-name
///         'virtual' access-specifier[opt] ::[opt] nested-name-specifier[opt]
///                        class-name
///         access-specifier 'virtual'[opt] ::[opt] nested-name-specifier[opt]
///                        class-name
Parser::BaseResult Parser::ParseBaseSpecifier(DeclPtrTy ClassDecl) {
  bool IsVirtual = false;
  SourceLocation StartLoc = Tok.getLocation();

  // Parse the 'virtual' keyword.
  if (Tok.is(tok::kw_virtual))  {
    ConsumeToken();
    IsVirtual = true;
  }

  // Parse an (optional) access specifier.
  AccessSpecifier Access = getAccessSpecifierIfPresent();
  if (Access)
    ConsumeToken();
  
  // Parse the 'virtual' keyword (again!), in case it came after the
  // access specifier.
  if (Tok.is(tok::kw_virtual))  {
    SourceLocation VirtualLoc = ConsumeToken();
    if (IsVirtual) {
      // Complain about duplicate 'virtual'
      Diag(VirtualLoc, diag::err_dup_virtual)
        << CodeModificationHint::CreateRemoval(SourceRange(VirtualLoc));
    }

    IsVirtual = true;
  }

  // Parse optional '::' and optional nested-name-specifier.
  CXXScopeSpec SS;
  ParseOptionalCXXScopeSpecifier(SS);

  // The location of the base class itself.
  SourceLocation BaseLoc = Tok.getLocation();

  // Parse the class-name.
  SourceLocation EndLocation;
  TypeResult BaseType = ParseClassName(EndLocation, &SS);
  if (BaseType.isInvalid())
    return true;
  
  // Find the complete source range for the base-specifier.  
  SourceRange Range(StartLoc, EndLocation);
  
  // Notify semantic analysis that we have parsed a complete
  // base-specifier.
  return Actions.ActOnBaseSpecifier(ClassDecl, Range, IsVirtual, Access,
                                    BaseType.get(), BaseLoc);
}

/// getAccessSpecifierIfPresent - Determine whether the next token is
/// a C++ access-specifier.
///
///       access-specifier: [C++ class.derived]
///         'private'
///         'protected'
///         'public'
AccessSpecifier Parser::getAccessSpecifierIfPresent() const
{
  switch (Tok.getKind()) {
  default: return AS_none;
  case tok::kw_private: return AS_private;
  case tok::kw_protected: return AS_protected;
  case tok::kw_public: return AS_public;
  }
}

/// ParseCXXClassMemberDeclaration - Parse a C++ class member declaration.
///
///       member-declaration:
///         decl-specifier-seq[opt] member-declarator-list[opt] ';'
///         function-definition ';'[opt]
///         ::[opt] nested-name-specifier template[opt] unqualified-id ';'[TODO]
///         using-declaration                                            [TODO]
/// [C++0x] static_assert-declaration
///         template-declaration
/// [GNU]   '__extension__' member-declaration
///
///       member-declarator-list:
///         member-declarator
///         member-declarator-list ',' member-declarator
///
///       member-declarator:
///         declarator pure-specifier[opt]
///         declarator constant-initializer[opt]
///         identifier[opt] ':' constant-expression
///
///       pure-specifier:
///         '= 0'
///
///       constant-initializer:
///         '=' constant-expression
///
void Parser::ParseCXXClassMemberDeclaration(AccessSpecifier AS) {
  // static_assert-declaration
  if (Tok.is(tok::kw_static_assert)) {
    SourceLocation DeclEnd;
    ParseStaticAssertDeclaration(DeclEnd);
    return;
  }
      
  if (Tok.is(tok::kw_template)) {
    SourceLocation DeclEnd;
    ParseDeclarationStartingWithTemplate(Declarator::MemberContext, DeclEnd, 
                                         AS);
    return;
  }

  // Handle:  member-declaration ::= '__extension__' member-declaration
  if (Tok.is(tok::kw___extension__)) {
    // __extension__ silences extension warnings in the subexpression.
    ExtensionRAIIObject O(Diags);  // Use RAII to do this.
    ConsumeToken();
    return ParseCXXClassMemberDeclaration(AS);
  }

  if (Tok.is(tok::kw_using)) {
    // Eat 'using'.
    SourceLocation UsingLoc = ConsumeToken();

    if (Tok.is(tok::kw_namespace)) {
      Diag(UsingLoc, diag::err_using_namespace_in_class);
      SkipUntil(tok::semi, true, true);
    }
    else {
      SourceLocation DeclEnd;
      // Otherwise, it must be using-declaration.
      ParseUsingDeclaration(Declarator::MemberContext, UsingLoc, DeclEnd);
    }
    return;
  }

  SourceLocation DSStart = Tok.getLocation();
  // decl-specifier-seq:
  // Parse the common declaration-specifiers piece.
  DeclSpec DS;
  ParseDeclarationSpecifiers(DS, ParsedTemplateInfo(), AS);

  if (Tok.is(tok::semi)) {
    ConsumeToken();
    // C++ 9.2p7: The member-declarator-list can be omitted only after a
    // class-specifier or an enum-specifier or in a friend declaration.
    // FIXME: Friend declarations.
    switch (DS.getTypeSpecType()) {
    case DeclSpec::TST_struct:
    case DeclSpec::TST_union:
    case DeclSpec::TST_class:
    case DeclSpec::TST_enum:
      Actions.ParsedFreeStandingDeclSpec(CurScope, DS);
      return;
    default:
      Diag(DSStart, diag::err_no_declarators);
      return;
    }
  }

  Declarator DeclaratorInfo(DS, Declarator::MemberContext);

  if (Tok.isNot(tok::colon)) {
    // Parse the first declarator.
    ParseDeclarator(DeclaratorInfo);
    // Error parsing the declarator?
    if (!DeclaratorInfo.hasName()) {
      // If so, skip until the semi-colon or a }.
      SkipUntil(tok::r_brace, true);
      if (Tok.is(tok::semi))
        ConsumeToken();
      return;
    }

    // function-definition:
    if (Tok.is(tok::l_brace)
        || (DeclaratorInfo.isFunctionDeclarator() &&
            (Tok.is(tok::colon) || Tok.is(tok::kw_try)))) {
      if (!DeclaratorInfo.isFunctionDeclarator()) {
        Diag(Tok, diag::err_func_def_no_params);
        ConsumeBrace();
        SkipUntil(tok::r_brace, true);
        return;
      }

      if (DS.getStorageClassSpec() == DeclSpec::SCS_typedef) {
        Diag(Tok, diag::err_function_declared_typedef);
        // This recovery skips the entire function body. It would be nice
        // to simply call ParseCXXInlineMethodDef() below, however Sema
        // assumes the declarator represents a function, not a typedef.
        ConsumeBrace();
        SkipUntil(tok::r_brace, true);
        return;
      }

      ParseCXXInlineMethodDef(AS, DeclaratorInfo);
      return;
    }
  }

  // member-declarator-list:
  //   member-declarator
  //   member-declarator-list ',' member-declarator

  llvm::SmallVector<DeclPtrTy, 8> DeclsInGroup;
  OwningExprResult BitfieldSize(Actions);
  OwningExprResult Init(Actions);
  bool Deleted = false;

  while (1) {

    // member-declarator:
    //   declarator pure-specifier[opt]
    //   declarator constant-initializer[opt]
    //   identifier[opt] ':' constant-expression

    if (Tok.is(tok::colon)) {
      ConsumeToken();
      BitfieldSize = ParseConstantExpression();
      if (BitfieldSize.isInvalid())
        SkipUntil(tok::comma, true, true);
    }
    
    // pure-specifier:
    //   '= 0'
    //
    // constant-initializer:
    //   '=' constant-expression
    //
    // defaulted/deleted function-definition:
    //   '=' 'default'                          [TODO]
    //   '=' 'delete'

    if (Tok.is(tok::equal)) {
      ConsumeToken();
      if (getLang().CPlusPlus0x && Tok.is(tok::kw_delete)) {
        ConsumeToken();
        Deleted = true;
      } else {
        Init = ParseInitializer();
        if (Init.isInvalid())
          SkipUntil(tok::comma, true, true);
      }
    }

    // If attributes exist after the declarator, parse them.
    if (Tok.is(tok::kw___attribute)) {
      SourceLocation Loc;
      AttributeList *AttrList = ParseAttributes(&Loc);
      DeclaratorInfo.AddAttributes(AttrList, Loc);
    }

    // NOTE: If Sema is the Action module and declarator is an instance field,
    // this call will *not* return the created decl; It will return null.
    // See Sema::ActOnCXXMemberDeclarator for details.
    DeclPtrTy ThisDecl = Actions.ActOnCXXMemberDeclarator(CurScope, AS,
                                                          DeclaratorInfo,
                                                          BitfieldSize.release(),
                                                          Init.release(),
                                                          Deleted);
    if (ThisDecl)
      DeclsInGroup.push_back(ThisDecl);

    if (DeclaratorInfo.isFunctionDeclarator() &&
        DeclaratorInfo.getDeclSpec().getStorageClassSpec() 
          != DeclSpec::SCS_typedef) {
      // We just declared a member function. If this member function
      // has any default arguments, we'll need to parse them later.
      LateParsedMethodDeclaration *LateMethod = 0;
      DeclaratorChunk::FunctionTypeInfo &FTI 
        = DeclaratorInfo.getTypeObject(0).Fun;
      for (unsigned ParamIdx = 0; ParamIdx < FTI.NumArgs; ++ParamIdx) {
        if (LateMethod || FTI.ArgInfo[ParamIdx].DefaultArgTokens) {
          if (!LateMethod) {
            // Push this method onto the stack of late-parsed method
            // declarations.
            getCurrentClass().MethodDecls.push_back(
                                   LateParsedMethodDeclaration(ThisDecl));
            LateMethod = &getCurrentClass().MethodDecls.back();

            // Add all of the parameters prior to this one (they don't
            // have default arguments).
            LateMethod->DefaultArgs.reserve(FTI.NumArgs);
            for (unsigned I = 0; I < ParamIdx; ++I)
              LateMethod->DefaultArgs.push_back(
                        LateParsedDefaultArgument(FTI.ArgInfo[ParamIdx].Param));
          }

          // Add this parameter to the list of parameters (it or may
          // not have a default argument).
          LateMethod->DefaultArgs.push_back(
            LateParsedDefaultArgument(FTI.ArgInfo[ParamIdx].Param,
                                      FTI.ArgInfo[ParamIdx].DefaultArgTokens));
        }
      }
    }

    // If we don't have a comma, it is either the end of the list (a ';')
    // or an error, bail out.
    if (Tok.isNot(tok::comma))
      break;
    
    // Consume the comma.
    ConsumeToken();
    
    // Parse the next declarator.
    DeclaratorInfo.clear();
    BitfieldSize = 0;
    Init = 0;
    Deleted = false;
    
    // Attributes are only allowed on the second declarator.
    if (Tok.is(tok::kw___attribute)) {
      SourceLocation Loc;
      AttributeList *AttrList = ParseAttributes(&Loc);
      DeclaratorInfo.AddAttributes(AttrList, Loc);
    }

    if (Tok.isNot(tok::colon))
      ParseDeclarator(DeclaratorInfo);
  }

  if (Tok.is(tok::semi)) {
    ConsumeToken();
    Actions.FinalizeDeclaratorGroup(CurScope, DS, DeclsInGroup.data(),
                                    DeclsInGroup.size());
    return;
  }

  Diag(Tok, diag::err_expected_semi_decl_list);
  // Skip to end of block or statement
  SkipUntil(tok::r_brace, true, true);
  if (Tok.is(tok::semi))
    ConsumeToken();
  return;
}

/// ParseCXXMemberSpecification - Parse the class definition.
///
///       member-specification:
///         member-declaration member-specification[opt]
///         access-specifier ':' member-specification[opt]
///
void Parser::ParseCXXMemberSpecification(SourceLocation RecordLoc,
                                         unsigned TagType, DeclPtrTy TagDecl) {
  assert((TagType == DeclSpec::TST_struct ||
         TagType == DeclSpec::TST_union  ||
         TagType == DeclSpec::TST_class) && "Invalid TagType!");

  PrettyStackTraceActionsDecl CrashInfo(TagDecl, RecordLoc, Actions,
                                        PP.getSourceManager(),
                                        "parsing struct/union/class body");
  
  SourceLocation LBraceLoc = ConsumeBrace();

  // Determine whether this is a top-level (non-nested) class.
  bool TopLevelClass = ClassStack.empty() || 
    CurScope->isInCXXInlineMethodScope();

  // Enter a scope for the class.
  ParseScope ClassScope(this, Scope::ClassScope|Scope::DeclScope);

  // Note that we are parsing a new (potentially-nested) class definition.
  ParsingClassDefinition ParsingDef(*this, TagDecl, TopLevelClass);

  if (TagDecl)
    Actions.ActOnTagStartDefinition(CurScope, TagDecl);
  else {
    SkipUntil(tok::r_brace, false, false);
    return;
  }

  // C++ 11p3: Members of a class defined with the keyword class are private
  // by default. Members of a class defined with the keywords struct or union
  // are public by default.
  AccessSpecifier CurAS;
  if (TagType == DeclSpec::TST_class)
    CurAS = AS_private;
  else
    CurAS = AS_public;

  // While we still have something to read, read the member-declarations.
  while (Tok.isNot(tok::r_brace) && Tok.isNot(tok::eof)) {
    // Each iteration of this loop reads one member-declaration.
    
    // Check for extraneous top-level semicolon.
    if (Tok.is(tok::semi)) {
      Diag(Tok, diag::ext_extra_struct_semi);
      ConsumeToken();
      continue;
    }

    AccessSpecifier AS = getAccessSpecifierIfPresent();
    if (AS != AS_none) {
      // Current token is a C++ access specifier.
      CurAS = AS;
      ConsumeToken();
      ExpectAndConsume(tok::colon, diag::err_expected_colon);
      continue;
    }

    // Parse all the comma separated declarators.
    ParseCXXClassMemberDeclaration(CurAS);
  }
  
  SourceLocation RBraceLoc = MatchRHSPunctuation(tok::r_brace, LBraceLoc);
  
  AttributeList *AttrList = 0;
  // If attributes exist after class contents, parse them.
  if (Tok.is(tok::kw___attribute))
    AttrList = ParseAttributes(); // FIXME: where should I put them?

  Actions.ActOnFinishCXXMemberSpecification(CurScope, RecordLoc, TagDecl,
                                            LBraceLoc, RBraceLoc);

  // C++ 9.2p2: Within the class member-specification, the class is regarded as
  // complete within function bodies, default arguments,
  // exception-specifications, and constructor ctor-initializers (including
  // such things in nested classes).
  //
  // FIXME: Only function bodies and constructor ctor-initializers are
  // parsed correctly, fix the rest.
  if (TopLevelClass) {
    // We are not inside a nested class. This class and its nested classes
    // are complete and we can parse the delayed portions of method
    // declarations and the lexed inline method definitions.
    ParseLexedMethodDeclarations(getCurrentClass());
    ParseLexedMethodDefs(getCurrentClass());
  }

  // Leave the class scope.
  ParsingDef.Pop();
  ClassScope.Exit();

  Actions.ActOnTagFinishDefinition(CurScope, TagDecl);
}

/// ParseConstructorInitializer - Parse a C++ constructor initializer,
/// which explicitly initializes the members or base classes of a
/// class (C++ [class.base.init]). For example, the three initializers
/// after the ':' in the Derived constructor below:
///
/// @code
/// class Base { };
/// class Derived : Base {
///   int x;
///   float f;
/// public:
///   Derived(float f) : Base(), x(17), f(f) { }
/// };
/// @endcode
///
/// [C++]  ctor-initializer: 
///          ':' mem-initializer-list 
///
/// [C++]  mem-initializer-list: 
///          mem-initializer 
///          mem-initializer , mem-initializer-list 
void Parser::ParseConstructorInitializer(DeclPtrTy ConstructorDecl) {
  assert(Tok.is(tok::colon) && "Constructor initializer always starts with ':'");

  SourceLocation ColonLoc = ConsumeToken();
  
  llvm::SmallVector<MemInitTy*, 4> MemInitializers;
  
  do {
    MemInitResult MemInit = ParseMemInitializer(ConstructorDecl);
    if (!MemInit.isInvalid())
      MemInitializers.push_back(MemInit.get());

    if (Tok.is(tok::comma))
      ConsumeToken();
    else if (Tok.is(tok::l_brace))
      break;
    else {
      // Skip over garbage, until we get to '{'.  Don't eat the '{'.
      Diag(Tok.getLocation(), diag::err_expected_lbrace_or_comma);
      SkipUntil(tok::l_brace, true, true);
      break;
    }
  } while (true);

  Actions.ActOnMemInitializers(ConstructorDecl, ColonLoc, 
                               MemInitializers.data(), MemInitializers.size());
}

/// ParseMemInitializer - Parse a C++ member initializer, which is
/// part of a constructor initializer that explicitly initializes one
/// member or base class (C++ [class.base.init]). See
/// ParseConstructorInitializer for an example.
///
/// [C++] mem-initializer:
///         mem-initializer-id '(' expression-list[opt] ')'
/// 
/// [C++] mem-initializer-id:
///         '::'[opt] nested-name-specifier[opt] class-name
///         identifier
Parser::MemInitResult Parser::ParseMemInitializer(DeclPtrTy ConstructorDecl) {
  // FIXME: parse '::'[opt] nested-name-specifier[opt]

  if (Tok.isNot(tok::identifier)) {
    Diag(Tok, diag::err_expected_member_or_base_name);
    return true;
  }

  // Get the identifier. This may be a member name or a class name,
  // but we'll let the semantic analysis determine which it is.
  IdentifierInfo *II = Tok.getIdentifierInfo();
  SourceLocation IdLoc = ConsumeToken();

  // Parse the '('.
  if (Tok.isNot(tok::l_paren)) {
    Diag(Tok, diag::err_expected_lparen);
    return true;
  }
  SourceLocation LParenLoc = ConsumeParen();

  // Parse the optional expression-list.
  ExprVector ArgExprs(Actions);
  CommaLocsTy CommaLocs;
  if (Tok.isNot(tok::r_paren) && ParseExpressionList(ArgExprs, CommaLocs)) {
    SkipUntil(tok::r_paren);
    return true;
  }

  SourceLocation RParenLoc = MatchRHSPunctuation(tok::r_paren, LParenLoc);

  return Actions.ActOnMemInitializer(ConstructorDecl, CurScope, II, IdLoc,
                                     LParenLoc, ArgExprs.take(),
                                     ArgExprs.size(), CommaLocs.data(),
                                     RParenLoc);
}

/// ParseExceptionSpecification - Parse a C++ exception-specification
/// (C++ [except.spec]).
///
///       exception-specification:
///         'throw' '(' type-id-list [opt] ')'
/// [MS]    'throw' '(' '...' ')'
///      
///       type-id-list:
///         type-id
///         type-id-list ',' type-id
///
bool Parser::ParseExceptionSpecification(SourceLocation &EndLoc,
                                         llvm::SmallVector<TypeTy*, 2>
                                             &Exceptions,
                                         llvm::SmallVector<SourceRange, 2>
                                             &Ranges,
                                         bool &hasAnyExceptionSpec) {
  assert(Tok.is(tok::kw_throw) && "expected throw");
  
  SourceLocation ThrowLoc = ConsumeToken();
  
  if (!Tok.is(tok::l_paren)) {
    return Diag(Tok, diag::err_expected_lparen_after) << "throw";
  }
  SourceLocation LParenLoc = ConsumeParen();

  // Parse throw(...), a Microsoft extension that means "this function
  // can throw anything".
  if (Tok.is(tok::ellipsis)) {
    hasAnyExceptionSpec = true;
    SourceLocation EllipsisLoc = ConsumeToken();
    if (!getLang().Microsoft)
      Diag(EllipsisLoc, diag::ext_ellipsis_exception_spec);
    EndLoc = MatchRHSPunctuation(tok::r_paren, LParenLoc);
    return false;
  }

  // Parse the sequence of type-ids.
  SourceRange Range;
  while (Tok.isNot(tok::r_paren)) {
    TypeResult Res(ParseTypeName(&Range));
    if (!Res.isInvalid()) {
      Exceptions.push_back(Res.get());
      Ranges.push_back(Range);
    }
    if (Tok.is(tok::comma))
      ConsumeToken();
    else
      break;
  }

  EndLoc = MatchRHSPunctuation(tok::r_paren, LParenLoc);
  return false;
}

/// \brief We have just started parsing the definition of a new class,
/// so push that class onto our stack of classes that is currently
/// being parsed.
void Parser::PushParsingClass(DeclPtrTy ClassDecl, bool TopLevelClass) {
  assert((TopLevelClass || !ClassStack.empty()) && 
         "Nested class without outer class");
  ClassStack.push(new ParsingClass(ClassDecl, TopLevelClass));
}

/// \brief Deallocate the given parsed class and all of its nested
/// classes.
void Parser::DeallocateParsedClasses(Parser::ParsingClass *Class) {
  for (unsigned I = 0, N = Class->NestedClasses.size(); I != N; ++I)
    DeallocateParsedClasses(Class->NestedClasses[I]);
  delete Class;
}

/// \brief Pop the top class of the stack of classes that are
/// currently being parsed.
///
/// This routine should be called when we have finished parsing the
/// definition of a class, but have not yet popped the Scope
/// associated with the class's definition.
///
/// \returns true if the class we've popped is a top-level class,
/// false otherwise.
void Parser::PopParsingClass() {
  assert(!ClassStack.empty() && "Mismatched push/pop for class parsing");
  
  ParsingClass *Victim = ClassStack.top();
  ClassStack.pop();
  if (Victim->TopLevelClass) {
    // Deallocate all of the nested classes of this class,
    // recursively: we don't need to keep any of this information.
    DeallocateParsedClasses(Victim);
    return;
  } 
  assert(!ClassStack.empty() && "Missing top-level class?");

  if (Victim->MethodDecls.empty() && Victim->MethodDefs.empty() &&
      Victim->NestedClasses.empty()) {
    // The victim is a nested class, but we will not need to perform
    // any processing after the definition of this class since it has
    // no members whose handling was delayed. Therefore, we can just
    // remove this nested class.
    delete Victim;
    return;
  }

  // This nested class has some members that will need to be processed
  // after the top-level class is completely defined. Therefore, add
  // it to the list of nested classes within its parent.
  assert(CurScope->isClassScope() && "Nested class outside of class scope?");
  ClassStack.top()->NestedClasses.push_back(Victim);
  Victim->TemplateScope = CurScope->getParent()->isTemplateParamScope();
}