C++ ExprResult::release方法代码示例

// Return true if a comma (or closing brace) is necessary after the
// __if_exists/if_not_exists statement.
bool Parser::ParseMicrosoftIfExistsBraceInitializer(ExprVector &InitExprs,
                                                    bool &InitExprsOk) {
  bool trailingComma = false;
  IfExistsCondition Result;
  if (ParseMicrosoftIfExistsCondition(Result))
    return false;
  
  BalancedDelimiterTracker Braces(*this, tok::l_brace);
  if (Braces.consumeOpen()) {
    Diag(Tok, diag::err_expected) << tok::l_brace;
    return false;
  }

  switch (Result.Behavior) {
  case IEB_Parse:
    // Parse the declarations below.
    break;
        
  case IEB_Dependent:
    Diag(Result.KeywordLoc, diag::warn_microsoft_dependent_exists)
      << Result.IsIfExists;
    // Fall through to skip.
      
  case IEB_Skip:
    Braces.skipToEnd();
    return false;
  }

  while (!isEofOrEom()) {
    trailingComma = false;
    // If we know that this cannot be a designation, just parse the nested
    // initializer directly.
    ExprResult SubElt;
    if (MayBeDesignationStart())
      SubElt = ParseInitializerWithPotentialDesignator();
    else
      SubElt = ParseInitializer();

    if (Tok.is(tok::ellipsis))
      SubElt = Actions.ActOnPackExpansion(SubElt.get(), ConsumeToken());
    
    // If we couldn't parse the subelement, bail out.
    if (!SubElt.isInvalid())
      InitExprs.push_back(SubElt.release());
    else
      InitExprsOk = false;

    if (Tok.is(tok::comma)) {
      ConsumeToken();
      trailingComma = true;
    }

    if (Tok.is(tok::r_brace))
      break;
  }

  Braces.consumeClose();

  return !trailingComma;
}

C2::StmtResult C2Sema::ActOnDoStmt(SourceLocation loc, ExprResult Cond, StmtResult Then) {
#ifdef SEMA_DEBUG
    std::cerr << COL_SEMA"SEMA: do statement at ";
    loc.dump(SourceMgr);
    std::cerr << ANSI_NORMAL"\n";
#endif
    return StmtResult(new DoStmt(loc, Cond.release(), Then.release()));
}

/// ParseTemplateArgument - Parse a C++ template argument (C++ [temp.names]).
///
///       template-argument: [C++ 14.2]
///         constant-expression
///         type-id
///         id-expression
ParsedTemplateArgument Parser::ParseTemplateArgument() {
  // C++ [temp.arg]p2:
  //   In a template-argument, an ambiguity between a type-id and an
  //   expression is resolved to a type-id, regardless of the form of
  //   the corresponding template-parameter.
  //
  // Therefore, we initially try to parse a type-id.  
  if (isCXXTypeId(TypeIdAsTemplateArgument)) {
    SourceLocation Loc = Tok.getLocation();
    TypeResult TypeArg = ParseTypeName(/*Range=*/0, 
                                       Declarator::TemplateTypeArgContext);
    if (TypeArg.isInvalid())
      return ParsedTemplateArgument();
    
    return ParsedTemplateArgument(ParsedTemplateArgument::Type,
                                  TypeArg.get().getAsOpaquePtr(), 
                                  Loc);
  }
  
  // Try to parse a template template argument.
  {
    TentativeParsingAction TPA(*this);

    ParsedTemplateArgument TemplateTemplateArgument
      = ParseTemplateTemplateArgument();
    if (!TemplateTemplateArgument.isInvalid()) {
      TPA.Commit();
      return TemplateTemplateArgument;
    }
    
    // Revert this tentative parse to parse a non-type template argument.
    TPA.Revert();
  }
  
  // Parse a non-type template argument. 
  SourceLocation Loc = Tok.getLocation();
  ExprResult ExprArg = ParseConstantExpression();
  if (ExprArg.isInvalid() || !ExprArg.get())
    return ParsedTemplateArgument();

  return ParsedTemplateArgument(ParsedTemplateArgument::NonType, 
                                ExprArg.release(), Loc);
}

/// ParseBraceInitializer - Called when parsing an initializer that has a
/// leading open brace.
///
///       initializer: [C99 6.7.8]
///         '{' initializer-list '}'
///         '{' initializer-list ',' '}'
/// [GNU]   '{' '}'
///
///       initializer-list:
///         designation[opt] initializer ...[opt]
///         initializer-list ',' designation[opt] initializer ...[opt]
///
ExprResult Parser::ParseBraceInitializer() {
  InMessageExpressionRAIIObject InMessage(*this, false);
  
  BalancedDelimiterTracker T(*this, tok::l_brace);
  T.consumeOpen();
  SourceLocation LBraceLoc = T.getOpenLocation();

  /// InitExprs - This is the actual list of expressions contained in the
  /// initializer.
  ExprVector InitExprs;

  if (Tok.is(tok::r_brace)) {
    // Empty initializers are a C++ feature and a GNU extension to C.
    if (!getLangOpts().CPlusPlus)
      Diag(LBraceLoc, diag::ext_gnu_empty_initializer);
    // Match the '}'.
    return Actions.ActOnInitList(LBraceLoc, None, ConsumeBrace());
  }

  bool InitExprsOk = true;

  while (1) {
    // Handle Microsoft __if_exists/if_not_exists if necessary.
    if (getLangOpts().MicrosoftExt && (Tok.is(tok::kw___if_exists) ||
        Tok.is(tok::kw___if_not_exists))) {
      if (ParseMicrosoftIfExistsBraceInitializer(InitExprs, InitExprsOk)) {
        if (Tok.isNot(tok::comma)) break;
        ConsumeToken();
      }
      if (Tok.is(tok::r_brace)) break;
      continue;
    }

    // Parse: designation[opt] initializer

    // If we know that this cannot be a designation, just parse the nested
    // initializer directly.
    ExprResult SubElt;
    if (MayBeDesignationStart())
      SubElt = ParseInitializerWithPotentialDesignator();
    else
      SubElt = ParseInitializer();

    if (Tok.is(tok::ellipsis))
      SubElt = Actions.ActOnPackExpansion(SubElt.get(), ConsumeToken());
    
    // If we couldn't parse the subelement, bail out.
    if (!SubElt.isInvalid()) {
      InitExprs.push_back(SubElt.release());
    } else {
      InitExprsOk = false;

      // We have two ways to try to recover from this error: if the code looks
      // grammatically ok (i.e. we have a comma coming up) try to continue
      // parsing the rest of the initializer.  This allows us to emit
      // diagnostics for later elements that we find.  If we don't see a comma,
      // assume there is a parse error, and just skip to recover.
      // FIXME: This comment doesn't sound right. If there is a r_brace
      // immediately, it can't be an error, since there is no other way of
      // leaving this loop except through this if.
      if (Tok.isNot(tok::comma)) {
        SkipUntil(tok::r_brace, StopBeforeMatch);
        break;
      }
    }

    // If we don't have a comma continued list, we're done.
    if (Tok.isNot(tok::comma)) break;

    // TODO: save comma locations if some client cares.
    ConsumeToken();

    // Handle trailing comma.
    if (Tok.is(tok::r_brace)) break;
  }

  bool closed = !T.consumeClose();

  if (InitExprsOk && closed)
    return Actions.ActOnInitList(LBraceLoc, InitExprs,
                                 T.getCloseLocation());

  return ExprError(); // an error occurred.
}

//.........这里部分代码省略.........
                                                             0);
        ConsumeToken(); // the identifier
        if (!ReceiverType) {
          SkipUntil(tok::r_square, StopAtSemi);
          return ExprError();
        }

        return ParseAssignmentExprWithObjCMessageExprStart(StartLoc, 
                                                           SourceLocation(), 
                                                           ReceiverType, 
                                                           0);

      case Sema::ObjCInstanceMessage:
        // Fall through; we'll just parse the expression and
        // (possibly) treat this like an Objective-C message send
        // later.
        break;
      }
    }

    // Parse the index expression, if we haven't already gotten one
    // above (which can only happen in Objective-C++).
    // Note that we parse this as an assignment expression, not a constant
    // expression (allowing *=, =, etc) to handle the objc case.  Sema needs
    // to validate that the expression is a constant.
    // FIXME: We also need to tell Sema that we're in a
    // potentially-potentially evaluated context.
    if (!Idx.get()) {
      Idx = ParseAssignmentExpression();
      if (Idx.isInvalid()) {
        SkipUntil(tok::r_square, StopAtSemi);
        return Idx;
      }
    }

    // Given an expression, we could either have a designator (if the next
    // tokens are '...' or ']' or an objc message send.  If this is an objc
    // message send, handle it now.  An objc-message send is the start of
    // an assignment-expression production.
    if (getLangOpts().ObjC1 && Tok.isNot(tok::ellipsis) &&
        Tok.isNot(tok::r_square)) {
      CheckArrayDesignatorSyntax(*this, Tok.getLocation(), Desig);
      return ParseAssignmentExprWithObjCMessageExprStart(StartLoc,
                                                         SourceLocation(),
                                                         ParsedType(),
                                                         Idx.take());
    }

    // If this is a normal array designator, remember it.
    if (Tok.isNot(tok::ellipsis)) {
      Desig.AddDesignator(Designator::getArray(Idx.release(), StartLoc));
    } else {
      // Handle the gnu array range extension.
      Diag(Tok, diag::ext_gnu_array_range);
      SourceLocation EllipsisLoc = ConsumeToken();

      ExprResult RHS(ParseConstantExpression());
      if (RHS.isInvalid()) {
        SkipUntil(tok::r_square, StopAtSemi);
        return RHS;
      }
      Desig.AddDesignator(Designator::getArrayRange(Idx.release(),
                                                    RHS.release(),
                                                    StartLoc, EllipsisLoc));
    }

    T.consumeClose();
    Desig.getDesignator(Desig.getNumDesignators() - 1).setRBracketLoc(
                                                        T.getCloseLocation());
  }

  // Okay, we're done with the designator sequence.  We know that there must be
  // at least one designator, because the only case we can get into this method
  // without a designator is when we have an objc message send.  That case is
  // handled and returned from above.
  assert(!Desig.empty() && "Designator is empty?");

  // Handle a normal designator sequence end, which is an equal.
  if (Tok.is(tok::equal)) {
    SourceLocation EqualLoc = ConsumeToken();
    return Actions.ActOnDesignatedInitializer(Desig, EqualLoc, false,
                                              ParseInitializer());
  }

  // We read some number of designators and found something that isn't an = or
  // an initializer.  If we have exactly one array designator, this
  // is the GNU 'designation: array-designator' extension.  Otherwise, it is a
  // parse error.
  if (Desig.getNumDesignators() == 1 &&
      (Desig.getDesignator(0).isArrayDesignator() ||
       Desig.getDesignator(0).isArrayRangeDesignator())) {
    Diag(Tok, diag::ext_gnu_missing_equal_designator)
      << FixItHint::CreateInsertion(Tok.getLocation(), "= ");
    return Actions.ActOnDesignatedInitializer(Desig, Tok.getLocation(),
                                              true, ParseInitializer());
  }

  Diag(Tok, diag::err_expected_equal_designator);
  return ExprError();
}

//.........这里部分代码省略.........
void PragmaPackHandler::HandlePragma(Preprocessor &PP, 
                                     PragmaIntroducerKind Introducer,
                                     Token &PackTok) {
  SourceLocation PackLoc = PackTok.getLocation();

  Token Tok;
  PP.Lex(Tok);
  if (Tok.isNot(tok::l_paren)) {
    PP.Diag(Tok.getLocation(), diag::warn_pragma_expected_lparen) << "pack";
    return;
  }

  Sema::PragmaPackKind Kind = Sema::PPK_Default;
  IdentifierInfo *Name = 0;
  ExprResult Alignment;
  SourceLocation LParenLoc = Tok.getLocation();
  PP.Lex(Tok);
  if (Tok.is(tok::numeric_constant)) {
    Alignment = Actions.ActOnNumericConstant(Tok);
    if (Alignment.isInvalid())
      return;

    PP.Lex(Tok);

    // In MSVC/gcc, #pragma pack(4) sets the alignment without affecting
    // the push/pop stack.
    // In Apple gcc, #pragma pack(4) is equivalent to #pragma pack(push, 4)
    if (PP.getLangOptions().ApplePragmaPack)
      Kind = Sema::PPK_Push;
  } else if (Tok.is(tok::identifier)) {
    const IdentifierInfo *II = Tok.getIdentifierInfo();
    if (II->isStr("show")) {
      Kind = Sema::PPK_Show;
      PP.Lex(Tok);
    } else {
      if (II->isStr("push")) {
        Kind = Sema::PPK_Push;
      } else if (II->isStr("pop")) {
        Kind = Sema::PPK_Pop;
      } else {
        PP.Diag(Tok.getLocation(), diag::warn_pragma_pack_invalid_action);
        return;
      }
      PP.Lex(Tok);

      if (Tok.is(tok::comma)) {
        PP.Lex(Tok);

        if (Tok.is(tok::numeric_constant)) {
          Alignment = Actions.ActOnNumericConstant(Tok);
          if (Alignment.isInvalid())
            return;

          PP.Lex(Tok);
        } else if (Tok.is(tok::identifier)) {
          Name = Tok.getIdentifierInfo();
          PP.Lex(Tok);

          if (Tok.is(tok::comma)) {
            PP.Lex(Tok);

            if (Tok.isNot(tok::numeric_constant)) {
              PP.Diag(Tok.getLocation(), diag::warn_pragma_pack_malformed);
              return;
            }

            Alignment = Actions.ActOnNumericConstant(Tok);
            if (Alignment.isInvalid())
              return;

            PP.Lex(Tok);
          }
        } else {
          PP.Diag(Tok.getLocation(), diag::warn_pragma_pack_malformed);
          return;
        }
      }
    }
  } else if (PP.getLangOptions().ApplePragmaPack) {
    // In MSVC/gcc, #pragma pack() resets the alignment without affecting
    // the push/pop stack.
    // In Apple gcc #pragma pack() is equivalent to #pragma pack(pop).
    Kind = Sema::PPK_Pop;
  }

  if (Tok.isNot(tok::r_paren)) {
    PP.Diag(Tok.getLocation(), diag::warn_pragma_expected_rparen) << "pack";
    return;
  }

  SourceLocation RParenLoc = Tok.getLocation();
  PP.Lex(Tok);
  if (Tok.isNot(tok::eod)) {
    PP.Diag(Tok.getLocation(), diag::warn_pragma_extra_tokens_at_eol) << "pack";
    return;
  }

  Actions.ActOnPragmaPack(Kind, Name, Alignment.release(), PackLoc,
                          LParenLoc, RParenLoc);
}

// #pragma pack(...) comes in the following delicious flavors:
//   pack '(' [integer] ')'
//   pack '(' 'show' ')'
//   pack '(' ('push' | 'pop') [',' identifier] [, integer] ')'
void PragmaPackHandler::HandlePragma(Preprocessor &PP, 
                                     PragmaIntroducerKind Introducer,
                                     Token &PackTok) {
  SourceLocation PackLoc = PackTok.getLocation();

  Token Tok;
  PP.Lex(Tok);
  if (Tok.isNot(tok::l_paren)) {
    PP.Diag(Tok.getLocation(), diag::warn_pragma_expected_lparen) << "pack";
    return;
  }

  Sema::PragmaPackKind Kind = Sema::PPK_Default;
  IdentifierInfo *Name = 0;
  ExprResult Alignment;
  SourceLocation LParenLoc = Tok.getLocation();
  PP.Lex(Tok);
  if (Tok.is(tok::numeric_constant)) {
    Alignment = Actions.ActOnNumericConstant(Tok);
    if (Alignment.isInvalid())
      return;

    PP.Lex(Tok);
  } else if (Tok.is(tok::identifier)) {
    const IdentifierInfo *II = Tok.getIdentifierInfo();
    if (II->isStr("show")) {
      Kind = Sema::PPK_Show;
      PP.Lex(Tok);
    } else {
      if (II->isStr("push")) {
        Kind = Sema::PPK_Push;
      } else if (II->isStr("pop")) {
        Kind = Sema::PPK_Pop;
      } else {
        PP.Diag(Tok.getLocation(), diag::warn_pragma_pack_invalid_action);
        return;
      }
      PP.Lex(Tok);

      if (Tok.is(tok::comma)) {
        PP.Lex(Tok);

        if (Tok.is(tok::numeric_constant)) {
          Alignment = Actions.ActOnNumericConstant(Tok);
          if (Alignment.isInvalid())
            return;

          PP.Lex(Tok);
        } else if (Tok.is(tok::identifier)) {
          Name = Tok.getIdentifierInfo();
          PP.Lex(Tok);

          if (Tok.is(tok::comma)) {
            PP.Lex(Tok);

            if (Tok.isNot(tok::numeric_constant)) {
              PP.Diag(Tok.getLocation(), diag::warn_pragma_pack_malformed);
              return;
            }

            Alignment = Actions.ActOnNumericConstant(Tok);
            if (Alignment.isInvalid())
              return;

            PP.Lex(Tok);
          }
        } else {
          PP.Diag(Tok.getLocation(), diag::warn_pragma_pack_malformed);
          return;
        }
      }
    }
  }

  if (Tok.isNot(tok::r_paren)) {
    PP.Diag(Tok.getLocation(), diag::warn_pragma_expected_rparen) << "pack";
    return;
  }

  SourceLocation RParenLoc = Tok.getLocation();
  PP.Lex(Tok);
  if (Tok.isNot(tok::eom)) {
    PP.Diag(Tok.getLocation(), diag::warn_pragma_extra_tokens_at_eol) << "pack";
    return;
  }

  Actions.ActOnPragmaPack(Kind, Name, Alignment.release(), PackLoc,
                          LParenLoc, RParenLoc);
}