C++ ExprResult类代码示例

Parser::ExprResult Parser::ParseAddOperand() {
  ExprResult E = ParseMultOperand();
  if (E.isInvalid()) return E;

  while (true) {
    SourceLocation OpLoc = Tok.getLocation();
    BinaryExpr::Operator Op = BinaryExpr::None;
    switch (Tok.getKind()) {
    default:
      return E;
    case tok::star:
      Op = BinaryExpr::Multiply;
      break;
    case tok::slash:
      Op = BinaryExpr::Divide;
      break;
    }

    Lex();
    ExprResult MulOp = ParseMultOperand();
    if (MulOp.isInvalid()) return MulOp;
    E = Actions.ActOnBinaryExpr(Context, OpLoc, Op, E, MulOp);
  }
  return E;
}

// 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;
}

/// ParseUnaryExpression - Parse a unary-expression.
///        unary-expression:
///          inc-dec-expression
///          ++ unary-expression
///          -- unary-expression
///          unary-operator unary-expression
ExprResult Parser::ParseUnaryExpression() {
	ExprResult Res;
	tok::TokenKind SavedKind = Tok.getKind();

	switch (SavedKind) {
	case tok::DoubleAdd:
	case tok::DoubleSub:
		// unary operators
	case tok::Addition:
	case tok::Subtraction:
	case tok::Tilde:
	case tok::At: {
		SourceLocation SavedLoc = ConsumeToken();
		Res = ParsePostfixExpression();
		if (!Res.isInvalid()) {
			Res = Actions.ActOnUnaryOp(getCurScope(), SavedLoc, SavedKind,false,
					                       Res.get());
		}
		return move(Res);
	}
	default:
		break;
	}

	return ParsePostfixExpression();
}

ExprResult ParserImpl::ParseUnaryParenExpr(const Token &Name,
                                           unsigned Kind, bool IsFixed,
                                           Expr::Width ResTy) {
  if (Tok.kind == Token::RParen) {
    Error("unexpected end of arguments.", Name);
    ConsumeRParen();
    return Builder->Constant(0, ResTy);
  }

  ExprResult Arg = ParseExpr(IsFixed ? ResTy : TypeResult());
  if (!Arg.isValid())
    Arg = Builder->Constant(0, ResTy);

  ExpectRParen("unexpected argument in unary expression.");  
  ExprHandle E = Arg.get();
  switch (Kind) {
  case eMacroKind_Neg:
    return Builder->Sub(Builder->Constant(0, E->getWidth()), E);
  case Expr::Not:
    // FIXME: Type check arguments.
    return Builder->Not(E);
  case Expr::SExt:
    // FIXME: Type check arguments.
    return Builder->SExt(E, ResTy);
  case Expr::ZExt:
    // FIXME: Type check arguments.
    return Builder->ZExt(E, ResTy);
  default:
    Error("internal error, unhandled kind.", Name);
    return Builder->Constant(0, ResTy);
  }
}

static ExprResult buildCoroutineHandle(Sema &S, QualType PromiseType,
                                       SourceLocation Loc) {
  QualType CoroHandleType = lookupCoroutineHandleType(S, PromiseType, Loc);
  if (CoroHandleType.isNull())
    return ExprError();

  DeclContext *LookupCtx = S.computeDeclContext(CoroHandleType);
  LookupResult Found(S, &S.PP.getIdentifierTable().get("from_address"), Loc,
                     Sema::LookupOrdinaryName);
  if (!S.LookupQualifiedName(Found, LookupCtx)) {
    S.Diag(Loc, diag::err_coroutine_handle_missing_member)
        << "from_address";
    return ExprError();
  }

  Expr *FramePtr =
      buildBuiltinCall(S, Loc, Builtin::BI__builtin_coro_frame, {});

  CXXScopeSpec SS;
  ExprResult FromAddr =
      S.BuildDeclarationNameExpr(SS, Found, /*NeedsADL=*/false);
  if (FromAddr.isInvalid())
    return ExprError();

  return S.ActOnCallExpr(nullptr, FromAddr.get(), Loc, FramePtr, Loc);
}

/// Look up the std::nothrow object.
static Expr *buildStdNoThrowDeclRef(Sema &S, SourceLocation Loc) {
  NamespaceDecl *Std = S.getStdNamespace();
  assert(Std && "Should already be diagnosed");

  LookupResult Result(S, &S.PP.getIdentifierTable().get("nothrow"), Loc,
                      Sema::LookupOrdinaryName);
  if (!S.LookupQualifiedName(Result, Std)) {
    // FIXME: <experimental/coroutine> should have been included already.
    // If we require it to include <new> then this diagnostic is no longer
    // needed.
    S.Diag(Loc, diag::err_implicit_coroutine_std_nothrow_type_not_found);
    return nullptr;
  }

  // FIXME: Mark the variable as ODR used. This currently does not work
  // likely due to the scope at in which this function is called.
  auto *VD = Result.getAsSingle<VarDecl>();
  if (!VD) {
    Result.suppressDiagnostics();
    // We found something weird. Complain about the first thing we found.
    NamedDecl *Found = *Result.begin();
    S.Diag(Found->getLocation(), diag::err_malformed_std_nothrow);
    return nullptr;
  }

  ExprResult DR = S.BuildDeclRefExpr(VD, VD->getType(), VK_LValue, Loc);
  if (DR.isInvalid())
    return nullptr;

  return DR.get();
}

ExprResult Sema::BuildCoyieldExpr(SourceLocation Loc, Expr *E) {
  auto *Coroutine = checkCoroutineContext(*this, Loc, "co_yield");
  if (!Coroutine)
    return ExprError();

  if (E->getType()->isPlaceholderType()) {
    ExprResult R = CheckPlaceholderExpr(E);
    if (R.isInvalid()) return ExprError();
    E = R.get();
  }

  if (E->getType()->isDependentType()) {
    Expr *Res = new (Context) CoyieldExpr(Loc, Context.DependentTy, E);
    return Res;
  }

  // If the expression is a temporary, materialize it as an lvalue so that we
  // can use it multiple times.
  if (E->getValueKind() == VK_RValue)
    E = CreateMaterializeTemporaryExpr(E->getType(), E, true);

  // Build the await_ready, await_suspend, await_resume calls.
  ReadySuspendResumeResult RSS =
      buildCoawaitCalls(*this, Coroutine->CoroutinePromise, Loc, E);
  if (RSS.IsInvalid)
    return ExprError();

  Expr *Res = new (Context) CoyieldExpr(Loc, E, RSS.Results[0], RSS.Results[1],
                                        RSS.Results[2], RSS.OpaqueValue);

  return Res;
}

// FIXME: Rewrite to only accept binary form. Make type optional.
ExprResult ParserImpl::ParseConcatParenExpr(const Token &Name,
                                            Expr::Width ResTy) {
  std::vector<ExprHandle> Kids;
  
  unsigned Width = 0;
  while (Tok.kind != Token::RParen) {
    ExprResult E = ParseExpr(TypeResult());

    // Skip to end of expr on error.
    if (!E.isValid()) {
      SkipUntilRParen();
      return Builder->Constant(0, ResTy);
    }
    
    Kids.push_back(E.get());
    Width += E.get()->getWidth();
  }
  
  ConsumeRParen();

  if (Width != ResTy) {
    Error("concat does not match expected result size.");
    return Builder->Constant(0, ResTy);
  }

  // FIXME: Use builder!
  return ConcatExpr::createN(Kids.size(), &Kids[0]);
}

ExprResult LogOrOpNode::eval()
{
	ExprResult left = mLeft->eval();
	ExprResult right = mRight->eval();
	ExprResult result("bool", (Val*)new BoolVal(left.getBoolVal() || right.getBoolVal()));
	return result;
}

static ExprResult buildOperatorCoawaitCall(Sema &SemaRef, Scope *S,
                                           SourceLocation Loc, Expr *E) {
  ExprResult R = buildOperatorCoawaitLookupExpr(SemaRef, S, Loc);
  if (R.isInvalid())
    return ExprError();
  return buildOperatorCoawaitCall(SemaRef, Loc, E,
                                  cast<UnresolvedLookupExpr>(R.get()));
}

C2::ExprResult C2Sema::ActOnArrayDesignatorExpr(SourceLocation left, ExprResult Designator, ExprResult InitValue) {
#ifdef SEMA_DEBUG
    std::cerr << COL_SEMA"SEMA: ArrayDesignatorExpr at ";
    left_.dump(SourceMgr);
    std::cerr << ANSI_NORMAL"\n";
#endif
    return ExprResult(new DesignatedInitExpr(left, Designator.get(), InitValue.get()));
}

IntegerResult ParserImpl::ParseIntegerConstant(Expr::Width Type) {
  ExprResult Res = ParseNumber(Type);

  if (!Res.isValid())
    return IntegerResult();

  return cast<ConstantExpr>(Res.get())->getZExtValue(Type);
}

ExprResult Sema::ActOnCoyieldExpr(SourceLocation Loc, Expr *E) {
  auto *Context = checkCoroutineContext(*this, Loc, "co_yield");
  ExprResult Res = ExprError();

  if (Context && !Res.isInvalid())
    Context->CoroutineStmts.push_back(Res.get());
  return Res;
}

static ExprResult
BuildFieldReferenceExpr(Sema &S, Expr *BaseExpr, bool IsArrow,
                        const CXXScopeSpec &SS, FieldDecl *Field,
                        DeclAccessPair FoundDecl,
                        const DeclarationNameInfo &MemberNameInfo) {
  // x.a is an l-value if 'a' has a reference type. Otherwise:
  // x.a is an l-value/x-value/pr-value if the base is (and note
  //   that *x is always an l-value), except that if the base isn't
  //   an ordinary object then we must have an rvalue.
  ExprValueKind VK = VK_LValue;
  ExprObjectKind OK = OK_Ordinary;
  if (!IsArrow) {
    if (BaseExpr->getObjectKind() == OK_Ordinary)
      VK = BaseExpr->getValueKind();
    else
      VK = VK_RValue;
  }
  if (VK != VK_RValue && Field->isBitField())
    OK = OK_BitField;
  
  // Figure out the type of the member; see C99 6.5.2.3p3, C++ [expr.ref]
  QualType MemberType = Field->getType();
  if (const ReferenceType *Ref = MemberType->getAs<ReferenceType>()) {
    MemberType = Ref->getPointeeType();
    VK = VK_LValue;
  } else {
    QualType BaseType = BaseExpr->getType();
    if (IsArrow) BaseType = BaseType->getAs<PointerType>()->getPointeeType();

    Qualifiers BaseQuals = BaseType.getQualifiers();

    // CVR attributes from the base are picked up by members,
    // except that 'mutable' members don't pick up 'const'.
    if (Field->isMutable()) BaseQuals.removeConst();

    Qualifiers MemberQuals
    = S.Context.getCanonicalType(MemberType).getQualifiers();

    assert(!MemberQuals.hasAddressSpace());


    Qualifiers Combined = BaseQuals + MemberQuals;
    if (Combined != MemberQuals)
      MemberType = S.Context.getQualifiedType(MemberType, Combined);
  }

  S.UnusedPrivateFields.remove(Field);

  ExprResult Base =
  S.PerformObjectMemberConversion(BaseExpr, SS.getScopeRep(),
                                  FoundDecl, Field);
  if (Base.isInvalid())
    return ExprError();
  return S.Owned(BuildMemberExpr(S, S.Context, Base.take(), IsArrow,
                                 Field, FoundDecl, MemberNameInfo,
                                 MemberType, VK, OK));
}

/// \brief Parsing of OpenMP clauses with single expressions and some additional
/// argument like 'schedule' or 'dist_schedule'.
///
///    schedule-clause:
///      'schedule' '(' kind [',' expression ] ')'
///
///    if-clause:
///      'if' '(' [ directive-name-modifier ':' ] expression ')'
///
OMPClause *Parser::ParseOpenMPSingleExprWithArgClause(OpenMPClauseKind Kind) {
  SourceLocation Loc = ConsumeToken();
  SourceLocation DelimLoc;
  // Parse '('.
  BalancedDelimiterTracker T(*this, tok::l_paren, tok::annot_pragma_openmp_end);
  if (T.expectAndConsume(diag::err_expected_lparen_after,
                         getOpenMPClauseName(Kind)))
    return nullptr;

  ExprResult Val;
  unsigned Arg;
  SourceLocation KLoc;
  if (Kind == OMPC_schedule) {
    Arg = getOpenMPSimpleClauseType(
        Kind, Tok.isAnnotation() ? "" : PP.getSpelling(Tok));
    KLoc = Tok.getLocation();
    if (Tok.isNot(tok::r_paren) && Tok.isNot(tok::comma) &&
        Tok.isNot(tok::annot_pragma_openmp_end))
      ConsumeAnyToken();
    if ((Arg == OMPC_SCHEDULE_static || Arg == OMPC_SCHEDULE_dynamic ||
         Arg == OMPC_SCHEDULE_guided) &&
        Tok.is(tok::comma))
      DelimLoc = ConsumeAnyToken();
  } else {
    assert(Kind == OMPC_if);
    KLoc = Tok.getLocation();
    Arg = ParseOpenMPDirectiveKind(*this);
    if (Arg != OMPD_unknown) {
      ConsumeToken();
      if (Tok.is(tok::colon))
        DelimLoc = ConsumeToken();
      else
        Diag(Tok, diag::warn_pragma_expected_colon)
            << "directive name modifier";
    }
  }

  bool NeedAnExpression =
      (Kind == OMPC_schedule && DelimLoc.isValid()) || Kind == OMPC_if;
  if (NeedAnExpression) {
    SourceLocation ELoc = Tok.getLocation();
    ExprResult LHS(ParseCastExpression(false, false, NotTypeCast));
    Val = ParseRHSOfBinaryExpression(LHS, prec::Conditional);
    Val = Actions.ActOnFinishFullExpr(Val.get(), ELoc);
  }

  // Parse ')'.
  T.consumeClose();

  if (NeedAnExpression && Val.isInvalid())
    return nullptr;

  return Actions.ActOnOpenMPSingleExprWithArgClause(
      Kind, Arg, Val.get(), Loc, T.getOpenLocation(), KLoc, DelimLoc,
      T.getCloseLocation());
}