C++ Sema::RequireCompleteType方法代码示例

/// Look up the std::experimental::coroutine_handle<PromiseType>.
static QualType lookupCoroutineHandleType(Sema &S, QualType PromiseType,
                                          SourceLocation Loc) {
  if (PromiseType.isNull())
    return QualType();

  NamespaceDecl *StdExp = S.lookupStdExperimentalNamespace();
  assert(StdExp && "Should already be diagnosed");

  LookupResult Result(S, &S.PP.getIdentifierTable().get("coroutine_handle"),
                      Loc, Sema::LookupOrdinaryName);
  if (!S.LookupQualifiedName(Result, StdExp)) {
    S.Diag(Loc, diag::err_implied_coroutine_type_not_found)
        << "std::experimental::coroutine_handle";
    return QualType();
  }

  ClassTemplateDecl *CoroHandle = Result.getAsSingle<ClassTemplateDecl>();
  if (!CoroHandle) {
    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_coroutine_handle);
    return QualType();
  }

  // Form template argument list for coroutine_handle<Promise>.
  TemplateArgumentListInfo Args(Loc, Loc);
  Args.addArgument(TemplateArgumentLoc(
      TemplateArgument(PromiseType),
      S.Context.getTrivialTypeSourceInfo(PromiseType, Loc)));

  // Build the template-id.
  QualType CoroHandleType =
      S.CheckTemplateIdType(TemplateName(CoroHandle), Loc, Args);
  if (CoroHandleType.isNull())
    return QualType();
  if (S.RequireCompleteType(Loc, CoroHandleType,
                            diag::err_coroutine_type_missing_specialization))
    return QualType();

  return CoroHandleType;
}

/// Look up the std::coroutine_traits<...>::promise_type for the given
/// function type.
static QualType lookupPromiseType(Sema &S, const FunctionProtoType *FnType,
                                  SourceLocation KwLoc,
                                  SourceLocation FuncLoc) {
  // FIXME: Cache std::coroutine_traits once we've found it.
  NamespaceDecl *StdExp = S.lookupStdExperimentalNamespace();
  if (!StdExp) {
    S.Diag(KwLoc, diag::err_implied_coroutine_type_not_found)
        << "std::experimental::coroutine_traits";
    return QualType();
  }

  LookupResult Result(S, &S.PP.getIdentifierTable().get("coroutine_traits"),
                      FuncLoc, Sema::LookupOrdinaryName);
  if (!S.LookupQualifiedName(Result, StdExp)) {
    S.Diag(KwLoc, diag::err_implied_coroutine_type_not_found)
        << "std::experimental::coroutine_traits";
    return QualType();
  }

  ClassTemplateDecl *CoroTraits = Result.getAsSingle<ClassTemplateDecl>();
  if (!CoroTraits) {
    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_coroutine_traits);
    return QualType();
  }

  // Form template argument list for coroutine_traits<R, P1, P2, ...>.
  TemplateArgumentListInfo Args(KwLoc, KwLoc);
  Args.addArgument(TemplateArgumentLoc(
      TemplateArgument(FnType->getReturnType()),
      S.Context.getTrivialTypeSourceInfo(FnType->getReturnType(), KwLoc)));
  // FIXME: If the function is a non-static member function, add the type
  // of the implicit object parameter before the formal parameters.
  for (QualType T : FnType->getParamTypes())
    Args.addArgument(TemplateArgumentLoc(
        TemplateArgument(T), S.Context.getTrivialTypeSourceInfo(T, KwLoc)));

  // Build the template-id.
  QualType CoroTrait =
      S.CheckTemplateIdType(TemplateName(CoroTraits), KwLoc, Args);
  if (CoroTrait.isNull())
    return QualType();
  if (S.RequireCompleteType(KwLoc, CoroTrait,
                            diag::err_coroutine_type_missing_specialization))
    return QualType();

  auto *RD = CoroTrait->getAsCXXRecordDecl();
  assert(RD && "specialization of class template is not a class?");

  // Look up the ::promise_type member.
  LookupResult R(S, &S.PP.getIdentifierTable().get("promise_type"), KwLoc,
                 Sema::LookupOrdinaryName);
  S.LookupQualifiedName(R, RD);
  auto *Promise = R.getAsSingle<TypeDecl>();
  if (!Promise) {
    S.Diag(FuncLoc,
           diag::err_implied_std_coroutine_traits_promise_type_not_found)
        << RD;
    return QualType();
  }
  // The promise type is required to be a class type.
  QualType PromiseType = S.Context.getTypeDeclType(Promise);

  auto buildElaboratedType = [&]() {
    auto *NNS = NestedNameSpecifier::Create(S.Context, nullptr, StdExp);
    NNS = NestedNameSpecifier::Create(S.Context, NNS, false,
                                      CoroTrait.getTypePtr());
    return S.Context.getElaboratedType(ETK_None, NNS, PromiseType);
  };

  if (!PromiseType->getAsCXXRecordDecl()) {
    S.Diag(FuncLoc,
           diag::err_implied_std_coroutine_traits_promise_type_not_class)
        << buildElaboratedType();
    return QualType();
  }
  if (S.RequireCompleteType(FuncLoc, buildElaboratedType(),
                            diag::err_coroutine_promise_type_incomplete))
    return QualType();

  return PromiseType;
}

/// CheckDynamicCast - Check that a dynamic_cast\<DestType\>(SrcExpr) is valid.
/// Refer to C++ 5.2.7 for details. Dynamic casts are used mostly for runtime-
/// checked downcasts in class hierarchies.
void
CheckDynamicCast(Sema &Self, Expr *&SrcExpr, QualType DestType,
                 const SourceRange &OpRange,
                 const SourceRange &DestRange)
{
  QualType OrigDestType = DestType, OrigSrcType = SrcExpr->getType();
  DestType = Self.Context.getCanonicalType(DestType);

  // C++ 5.2.7p1: T shall be a pointer or reference to a complete class type,
  //   or "pointer to cv void".

  QualType DestPointee;
  const PointerType *DestPointer = DestType->getAsPointerType();
  const ReferenceType *DestReference = DestType->getAsReferenceType();
  if (DestPointer) {
    DestPointee = DestPointer->getPointeeType();
  } else if (DestReference) {
    DestPointee = DestReference->getPointeeType();
  } else {
    Self.Diag(OpRange.getBegin(), diag::err_bad_dynamic_cast_not_ref_or_ptr)
      << OrigDestType << DestRange;
    return;
  }

  const RecordType *DestRecord = DestPointee->getAsRecordType();
  if (DestPointee->isVoidType()) {
    assert(DestPointer && "Reference to void is not possible");
  } else if (DestRecord) {
    if (Self.RequireCompleteType(OpRange.getBegin(), DestPointee, 
                                    diag::err_bad_dynamic_cast_incomplete,
                                    DestRange))
      return;
  } else {
    Self.Diag(OpRange.getBegin(), diag::err_bad_dynamic_cast_not_class)
      << DestPointee.getUnqualifiedType() << DestRange;
    return;
  }

  // C++0x 5.2.7p2: If T is a pointer type, v shall be an rvalue of a pointer to
  //   complete class type, [...]. If T is an lvalue reference type, v shall be
  //   an lvalue of a complete class type, [...]. If T is an rvalue reference
  //   type, v shall be an expression having a complete effective class type,
  //   [...]

  QualType SrcType = Self.Context.getCanonicalType(OrigSrcType);
  QualType SrcPointee;
  if (DestPointer) {
    if (const PointerType *SrcPointer = SrcType->getAsPointerType()) {
      SrcPointee = SrcPointer->getPointeeType();
    } else {
      Self.Diag(OpRange.getBegin(), diag::err_bad_dynamic_cast_not_ptr)
        << OrigSrcType << SrcExpr->getSourceRange();
      return;
    }
  } else if (DestReference->isLValueReferenceType()) {
    if (SrcExpr->isLvalue(Self.Context) != Expr::LV_Valid) {
      Self.Diag(OpRange.getBegin(), diag::err_bad_cxx_cast_rvalue)
        << "dynamic_cast" << OrigDestType << OpRange;
    }
    SrcPointee = SrcType;
  } else {
    SrcPointee = SrcType;
  }

  const RecordType *SrcRecord = SrcPointee->getAsRecordType();
  if (SrcRecord) {
    if (Self.RequireCompleteType(OpRange.getBegin(), SrcPointee,
                                    diag::err_bad_dynamic_cast_incomplete,
                                    SrcExpr->getSourceRange()))
      return;
  } else {
    Self.Diag(OpRange.getBegin(), diag::err_bad_dynamic_cast_not_class)
      << SrcPointee.getUnqualifiedType() << SrcExpr->getSourceRange();
    return;
  }

  assert((DestPointer || DestReference) &&
    "Bad destination non-ptr/ref slipped through.");
  assert((DestRecord || DestPointee->isVoidType()) &&
    "Bad destination pointee slipped through.");
  assert(SrcRecord && "Bad source pointee slipped through.");

  // C++ 5.2.7p1: The dynamic_cast operator shall not cast away constness.
  if (!DestPointee.isAtLeastAsQualifiedAs(SrcPointee)) {
    Self.Diag(OpRange.getBegin(), diag::err_bad_cxx_cast_const_away)
      << "dynamic_cast" << OrigDestType << OrigSrcType << OpRange;
    return;
  }

  // C++ 5.2.7p3: If the type of v is the same as the required result type,
  //   [except for cv].
  if (DestRecord == SrcRecord) {
    return;
  }

  // C++ 5.2.7p5
  // Upcasts are resolved statically.
//.........这里部分代码省略.........